Merge of 'misc-fixes' branch from
[linux-2.6] / drivers / ide / ide-tape.c
1 /*
2  * linux/drivers/ide/ide-tape.c         Version 1.19    Nov, 2003
3  *
4  * Copyright (C) 1995 - 1999 Gadi Oxman <gadio@netvision.net.il>
5  *
6  * $Header$
7  *
8  * This driver was constructed as a student project in the software laboratory
9  * of the faculty of electrical engineering in the Technion - Israel's
10  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
11  *
12  * It is hereby placed under the terms of the GNU general public license.
13  * (See linux/COPYING).
14  */
15  
16 /*
17  * IDE ATAPI streaming tape driver.
18  *
19  * This driver is a part of the Linux ide driver and works in co-operation
20  * with linux/drivers/block/ide.c.
21  *
22  * The driver, in co-operation with ide.c, basically traverses the 
23  * request-list for the block device interface. The character device
24  * interface, on the other hand, creates new requests, adds them
25  * to the request-list of the block device, and waits for their completion.
26  *
27  * Pipelined operation mode is now supported on both reads and writes.
28  *
29  * The block device major and minor numbers are determined from the
30  * tape's relative position in the ide interfaces, as explained in ide.c.
31  *
32  * The character device interface consists of the following devices:
33  *
34  * ht0          major 37, minor 0       first  IDE tape, rewind on close.
35  * ht1          major 37, minor 1       second IDE tape, rewind on close.
36  * ...
37  * nht0         major 37, minor 128     first  IDE tape, no rewind on close.
38  * nht1         major 37, minor 129     second IDE tape, no rewind on close.
39  * ...
40  *
41  * Run linux/scripts/MAKEDEV.ide to create the above entries.
42  *
43  * The general magnetic tape commands compatible interface, as defined by
44  * include/linux/mtio.h, is accessible through the character device.
45  *
46  * General ide driver configuration options, such as the interrupt-unmask
47  * flag, can be configured by issuing an ioctl to the block device interface,
48  * as any other ide device.
49  *
50  * Our own ide-tape ioctl's can be issued to either the block device or
51  * the character device interface.
52  *
53  * Maximal throughput with minimal bus load will usually be achieved in the
54  * following scenario:
55  *
56  *      1.      ide-tape is operating in the pipelined operation mode.
57  *      2.      No buffering is performed by the user backup program.
58  *
59  * Testing was done with a 2 GB CONNER CTMA 4000 IDE ATAPI Streaming Tape Drive.
60  * 
61  * Ver 0.1   Nov  1 95   Pre-working code :-)
62  * Ver 0.2   Nov 23 95   A short backup (few megabytes) and restore procedure
63  *                        was successful ! (Using tar cvf ... on the block
64  *                        device interface).
65  *                       A longer backup resulted in major swapping, bad
66  *                        overall Linux performance and eventually failed as
67  *                        we received non serial read-ahead requests from the
68  *                        buffer cache.
69  * Ver 0.3   Nov 28 95   Long backups are now possible, thanks to the
70  *                        character device interface. Linux's responsiveness
71  *                        and performance doesn't seem to be much affected
72  *                        from the background backup procedure.
73  *                       Some general mtio.h magnetic tape operations are
74  *                        now supported by our character device. As a result,
75  *                        popular tape utilities are starting to work with
76  *                        ide tapes :-)
77  *                       The following configurations were tested:
78  *                              1. An IDE ATAPI TAPE shares the same interface
79  *                                 and irq with an IDE ATAPI CDROM.
80  *                              2. An IDE ATAPI TAPE shares the same interface
81  *                                 and irq with a normal IDE disk.
82  *                        Both configurations seemed to work just fine !
83  *                        However, to be on the safe side, it is meanwhile
84  *                        recommended to give the IDE TAPE its own interface
85  *                        and irq.
86  *                       The one thing which needs to be done here is to
87  *                        add a "request postpone" feature to ide.c,
88  *                        so that we won't have to wait for the tape to finish
89  *                        performing a long media access (DSC) request (such
90  *                        as a rewind) before we can access the other device
91  *                        on the same interface. This effect doesn't disturb
92  *                        normal operation most of the time because read/write
93  *                        requests are relatively fast, and once we are
94  *                        performing one tape r/w request, a lot of requests
95  *                        from the other device can be queued and ide.c will
96  *                        service all of them after this single tape request.
97  * Ver 1.0   Dec 11 95   Integrated into Linux 1.3.46 development tree.
98  *                       On each read / write request, we now ask the drive
99  *                        if we can transfer a constant number of bytes
100  *                        (a parameter of the drive) only to its buffers,
101  *                        without causing actual media access. If we can't,
102  *                        we just wait until we can by polling the DSC bit.
103  *                        This ensures that while we are not transferring
104  *                        more bytes than the constant referred to above, the
105  *                        interrupt latency will not become too high and
106  *                        we won't cause an interrupt timeout, as happened
107  *                        occasionally in the previous version.
108  *                       While polling for DSC, the current request is
109  *                        postponed and ide.c is free to handle requests from
110  *                        the other device. This is handled transparently to
111  *                        ide.c. The hwgroup locking method which was used
112  *                        in the previous version was removed.
113  *                       Use of new general features which are provided by
114  *                        ide.c for use with atapi devices.
115  *                        (Programming done by Mark Lord)
116  *                       Few potential bug fixes (Again, suggested by Mark)
117  *                       Single character device data transfers are now
118  *                        not limited in size, as they were before.
119  *                       We are asking the tape about its recommended
120  *                        transfer unit and send a larger data transfer
121  *                        as several transfers of the above size.
122  *                        For best results, use an integral number of this
123  *                        basic unit (which is shown during driver
124  *                        initialization). I will soon add an ioctl to get
125  *                        this important parameter.
126  *                       Our data transfer buffer is allocated on startup,
127  *                        rather than before each data transfer. This should
128  *                        ensure that we will indeed have a data buffer.
129  * Ver 1.1   Dec 14 95   Fixed random problems which occurred when the tape
130  *                        shared an interface with another device.
131  *                        (poll_for_dsc was a complete mess).
132  *                       Removed some old (non-active) code which had
133  *                        to do with supporting buffer cache originated
134  *                        requests.
135  *                       The block device interface can now be opened, so
136  *                        that general ide driver features like the unmask
137  *                        interrupts flag can be selected with an ioctl.
138  *                        This is the only use of the block device interface.
139  *                       New fast pipelined operation mode (currently only on
140  *                        writes). When using the pipelined mode, the
141  *                        throughput can potentially reach the maximum
142  *                        tape supported throughput, regardless of the
143  *                        user backup program. On my tape drive, it sometimes
144  *                        boosted performance by a factor of 2. Pipelined
145  *                        mode is enabled by default, but since it has a few
146  *                        downfalls as well, you may want to disable it.
147  *                        A short explanation of the pipelined operation mode
148  *                        is available below.
149  * Ver 1.2   Jan  1 96   Eliminated pipelined mode race condition.
150  *                       Added pipeline read mode. As a result, restores
151  *                        are now as fast as backups.
152  *                       Optimized shared interface behavior. The new behavior
153  *                        typically results in better IDE bus efficiency and
154  *                        higher tape throughput.
155  *                       Pre-calculation of the expected read/write request
156  *                        service time, based on the tape's parameters. In
157  *                        the pipelined operation mode, this allows us to
158  *                        adjust our polling frequency to a much lower value,
159  *                        and thus to dramatically reduce our load on Linux,
160  *                        without any decrease in performance.
161  *                       Implemented additional mtio.h operations.
162  *                       The recommended user block size is returned by
163  *                        the MTIOCGET ioctl.
164  *                       Additional minor changes.
165  * Ver 1.3   Feb  9 96   Fixed pipelined read mode bug which prevented the
166  *                        use of some block sizes during a restore procedure.
167  *                       The character device interface will now present a
168  *                        continuous view of the media - any mix of block sizes
169  *                        during a backup/restore procedure is supported. The
170  *                        driver will buffer the requests internally and
171  *                        convert them to the tape's recommended transfer
172  *                        unit, making performance almost independent of the
173  *                        chosen user block size.
174  *                       Some improvements in error recovery.
175  *                       By cooperating with ide-dma.c, bus mastering DMA can
176  *                        now sometimes be used with IDE tape drives as well.
177  *                        Bus mastering DMA has the potential to dramatically
178  *                        reduce the CPU's overhead when accessing the device,
179  *                        and can be enabled by using hdparm -d1 on the tape's
180  *                        block device interface. For more info, read the
181  *                        comments in ide-dma.c.
182  * Ver 1.4   Mar 13 96   Fixed serialize support.
183  * Ver 1.5   Apr 12 96   Fixed shared interface operation, broken in 1.3.85.
184  *                       Fixed pipelined read mode inefficiency.
185  *                       Fixed nasty null dereferencing bug.
186  * Ver 1.6   Aug 16 96   Fixed FPU usage in the driver.
187  *                       Fixed end of media bug.
188  * Ver 1.7   Sep 10 96   Minor changes for the CONNER CTT8000-A model.
189  * Ver 1.8   Sep 26 96   Attempt to find a better balance between good
190  *                        interactive response and high system throughput.
191  * Ver 1.9   Nov  5 96   Automatically cross encountered filemarks rather
192  *                        than requiring an explicit FSF command.
193  *                       Abort pending requests at end of media.
194  *                       MTTELL was sometimes returning incorrect results.
195  *                       Return the real block size in the MTIOCGET ioctl.
196  *                       Some error recovery bug fixes.
197  * Ver 1.10  Nov  5 96   Major reorganization.
198  *                       Reduced CPU overhead a bit by eliminating internal
199  *                        bounce buffers.
200  *                       Added module support.
201  *                       Added multiple tape drives support.
202  *                       Added partition support.
203  *                       Rewrote DSC handling.
204  *                       Some portability fixes.
205  *                       Removed ide-tape.h.
206  *                       Additional minor changes.
207  * Ver 1.11  Dec  2 96   Bug fix in previous DSC timeout handling.
208  *                       Use ide_stall_queue() for DSC overlap.
209  *                       Use the maximum speed rather than the current speed
210  *                        to compute the request service time.
211  * Ver 1.12  Dec  7 97   Fix random memory overwriting and/or last block data
212  *                        corruption, which could occur if the total number
213  *                        of bytes written to the tape was not an integral
214  *                        number of tape blocks.
215  *                       Add support for INTERRUPT DRQ devices.
216  * Ver 1.13  Jan  2 98   Add "speed == 0" work-around for HP COLORADO 5GB
217  * Ver 1.14  Dec 30 98   Partial fixes for the Sony/AIWA tape drives.
218  *                       Replace cli()/sti() with hwgroup spinlocks.
219  * Ver 1.15  Mar 25 99   Fix SMP race condition by replacing hwgroup
220  *                        spinlock with private per-tape spinlock.
221  * Ver 1.16  Sep  1 99   Add OnStream tape support.
222  *                       Abort read pipeline on EOD.
223  *                       Wait for the tape to become ready in case it returns
224  *                        "in the process of becoming ready" on open().
225  *                       Fix zero padding of the last written block in
226  *                        case the tape block size is larger than PAGE_SIZE.
227  *                       Decrease the default disconnection time to tn.
228  * Ver 1.16e Oct  3 99   Minor fixes.
229  * Ver 1.16e1 Oct 13 99  Patches by Arnold Niessen,
230  *                          niessen@iae.nl / arnold.niessen@philips.com
231  *                   GO-1)  Undefined code in idetape_read_position
232  *                              according to Gadi's email
233  *                   AJN-1) Minor fix asc == 11 should be asc == 0x11
234  *                               in idetape_issue_packet_command (did effect
235  *                               debugging output only)
236  *                   AJN-2) Added more debugging output, and
237  *                              added ide-tape: where missing. I would also
238  *                              like to add tape->name where possible
239  *                   AJN-3) Added different debug_level's 
240  *                              via /proc/ide/hdc/settings
241  *                              "debug_level" determines amount of debugging output;
242  *                              can be changed using /proc/ide/hdx/settings
243  *                              0 : almost no debugging output
244  *                              1 : 0+output errors only
245  *                              2 : 1+output all sensekey/asc
246  *                              3 : 2+follow all chrdev related procedures
247  *                              4 : 3+follow all procedures
248  *                              5 : 4+include pc_stack rq_stack info
249  *                              6 : 5+USE_COUNT updates
250  *                   AJN-4) Fixed timeout for retension in idetape_queue_pc_tail
251  *                              from 5 to 10 minutes
252  *                   AJN-5) Changed maximum number of blocks to skip when
253  *                              reading tapes with multiple consecutive write
254  *                              errors from 100 to 1000 in idetape_get_logical_blk
255  *                   Proposed changes to code:
256  *                   1) output "logical_blk_num" via /proc
257  *                   2) output "current_operation" via /proc
258  *                   3) Either solve or document the fact that `mt rewind' is
259  *                      required after reading from /dev/nhtx to be
260  *                      able to rmmod the idetape module;
261  *                      Also, sometimes an application finishes but the
262  *                      device remains `busy' for some time. Same cause ?
263  *                   Proposed changes to release-notes:
264  *                   4) write a simple `quickstart' section in the
265  *                      release notes; I volunteer if you don't want to
266  *                   5) include a pointer to video4linux in the doc
267  *                      to stimulate video applications
268  *                   6) release notes lines 331 and 362: explain what happens
269  *                      if the application data rate is higher than 1100 KB/s; 
270  *                      similar approach to lower-than-500 kB/s ?
271  *                   7) 6.6 Comparison; wouldn't it be better to allow different 
272  *                      strategies for read and write ?
273  *                      Wouldn't it be better to control the tape buffer
274  *                      contents instead of the bandwidth ?
275  *                   8) line 536: replace will by would (if I understand
276  *                      this section correctly, a hypothetical and unwanted situation
277  *                       is being described)
278  * Ver 1.16f Dec 15 99   Change place of the secondary OnStream header frames.
279  * Ver 1.17  Nov 2000 / Jan 2001  Marcel Mol, marcel@mesa.nl
280  *                      - Add idetape_onstream_mode_sense_tape_parameter_page
281  *                        function to get tape capacity in frames: tape->capacity.
282  *                      - Add support for DI-50 drives( or any DI- drive).
283  *                      - 'workaround' for read error/blank block around block 3000.
284  *                      - Implement Early warning for end of media for Onstream.
285  *                      - Cosmetic code changes for readability.
286  *                      - Idetape_position_tape should not use SKIP bit during
287  *                        Onstream read recovery.
288  *                      - Add capacity, logical_blk_num and first/last_frame_position
289  *                        to /proc/ide/hd?/settings.
290  *                      - Module use count was gone in the Linux 2.4 driver.
291  * Ver 1.17a Apr 2001 Willem Riede osst@riede.org
292  *                      - Get drive's actual block size from mode sense block descriptor
293  *                      - Limit size of pipeline
294  * Ver 1.17b Oct 2002   Alan Stern <stern@rowland.harvard.edu>
295  *                      Changed IDETAPE_MIN_PIPELINE_STAGES to 1 and actually used
296  *                       it in the code!
297  *                      Actually removed aborted stages in idetape_abort_pipeline
298  *                       instead of just changing the command code.
299  *                      Made the transfer byte count for Request Sense equal to the
300  *                       actual length of the data transfer.
301  *                      Changed handling of partial data transfers: they do not
302  *                       cause DMA errors.
303  *                      Moved initiation of DMA transfers to the correct place.
304  *                      Removed reference to unallocated memory.
305  *                      Made __idetape_discard_read_pipeline return the number of
306  *                       sectors skipped, not the number of stages.
307  *                      Replaced errant kfree() calls with __idetape_kfree_stage().
308  *                      Fixed off-by-one error in testing the pipeline length.
309  *                      Fixed handling of filemarks in the read pipeline.
310  *                      Small code optimization for MTBSF and MTBSFM ioctls.
311  *                      Don't try to unlock the door during device close if is
312  *                       already unlocked!
313  *                      Cosmetic fixes to miscellaneous debugging output messages.
314  *                      Set the minimum /proc/ide/hd?/settings values for "pipeline",
315  *                       "pipeline_min", and "pipeline_max" to 1.
316  *
317  * Here are some words from the first releases of hd.c, which are quoted
318  * in ide.c and apply here as well:
319  *
320  * | Special care is recommended.  Have Fun!
321  *
322  */
323
324 /*
325  * An overview of the pipelined operation mode.
326  *
327  * In the pipelined write mode, we will usually just add requests to our
328  * pipeline and return immediately, before we even start to service them. The
329  * user program will then have enough time to prepare the next request while
330  * we are still busy servicing previous requests. In the pipelined read mode,
331  * the situation is similar - we add read-ahead requests into the pipeline,
332  * before the user even requested them.
333  *
334  * The pipeline can be viewed as a "safety net" which will be activated when
335  * the system load is high and prevents the user backup program from keeping up
336  * with the current tape speed. At this point, the pipeline will get
337  * shorter and shorter but the tape will still be streaming at the same speed.
338  * Assuming we have enough pipeline stages, the system load will hopefully
339  * decrease before the pipeline is completely empty, and the backup program
340  * will be able to "catch up" and refill the pipeline again.
341  * 
342  * When using the pipelined mode, it would be best to disable any type of
343  * buffering done by the user program, as ide-tape already provides all the
344  * benefits in the kernel, where it can be done in a more efficient way.
345  * As we will usually not block the user program on a request, the most
346  * efficient user code will then be a simple read-write-read-... cycle.
347  * Any additional logic will usually just slow down the backup process.
348  *
349  * Using the pipelined mode, I get a constant over 400 KBps throughput,
350  * which seems to be the maximum throughput supported by my tape.
351  *
352  * However, there are some downfalls:
353  *
354  *      1.      We use memory (for data buffers) in proportional to the number
355  *              of pipeline stages (each stage is about 26 KB with my tape).
356  *      2.      In the pipelined write mode, we cheat and postpone error codes
357  *              to the user task. In read mode, the actual tape position
358  *              will be a bit further than the last requested block.
359  *
360  * Concerning (1):
361  *
362  *      1.      We allocate stages dynamically only when we need them. When
363  *              we don't need them, we don't consume additional memory. In
364  *              case we can't allocate stages, we just manage without them
365  *              (at the expense of decreased throughput) so when Linux is
366  *              tight in memory, we will not pose additional difficulties.
367  *
368  *      2.      The maximum number of stages (which is, in fact, the maximum
369  *              amount of memory) which we allocate is limited by the compile
370  *              time parameter IDETAPE_MAX_PIPELINE_STAGES.
371  *
372  *      3.      The maximum number of stages is a controlled parameter - We
373  *              don't start from the user defined maximum number of stages
374  *              but from the lower IDETAPE_MIN_PIPELINE_STAGES (again, we
375  *              will not even allocate this amount of stages if the user
376  *              program can't handle the speed). We then implement a feedback
377  *              loop which checks if the pipeline is empty, and if it is, we
378  *              increase the maximum number of stages as necessary until we
379  *              reach the optimum value which just manages to keep the tape
380  *              busy with minimum allocated memory or until we reach
381  *              IDETAPE_MAX_PIPELINE_STAGES.
382  *
383  * Concerning (2):
384  *
385  *      In pipelined write mode, ide-tape can not return accurate error codes
386  *      to the user program since we usually just add the request to the
387  *      pipeline without waiting for it to be serviced. In case an error
388  *      occurs, I will report it on the next user request.
389  *
390  *      In the pipelined read mode, subsequent read requests or forward
391  *      filemark spacing will perform correctly, as we preserve all blocks
392  *      and filemarks which we encountered during our excess read-ahead.
393  * 
394  *      For accurate tape positioning and error reporting, disabling
395  *      pipelined mode might be the best option.
396  *
397  * You can enable/disable/tune the pipelined operation mode by adjusting
398  * the compile time parameters below.
399  */
400
401 /*
402  *      Possible improvements.
403  *
404  *      1.      Support for the ATAPI overlap protocol.
405  *
406  *              In order to maximize bus throughput, we currently use the DSC
407  *              overlap method which enables ide.c to service requests from the
408  *              other device while the tape is busy executing a command. The
409  *              DSC overlap method involves polling the tape's status register
410  *              for the DSC bit, and servicing the other device while the tape
411  *              isn't ready.
412  *
413  *              In the current QIC development standard (December 1995),
414  *              it is recommended that new tape drives will *in addition* 
415  *              implement the ATAPI overlap protocol, which is used for the
416  *              same purpose - efficient use of the IDE bus, but is interrupt
417  *              driven and thus has much less CPU overhead.
418  *
419  *              ATAPI overlap is likely to be supported in most new ATAPI
420  *              devices, including new ATAPI cdroms, and thus provides us
421  *              a method by which we can achieve higher throughput when
422  *              sharing a (fast) ATA-2 disk with any (slow) new ATAPI device.
423  */
424
425 #define IDETAPE_VERSION "1.19"
426
427 #include <linux/config.h>
428 #include <linux/module.h>
429 #include <linux/types.h>
430 #include <linux/string.h>
431 #include <linux/kernel.h>
432 #include <linux/delay.h>
433 #include <linux/timer.h>
434 #include <linux/mm.h>
435 #include <linux/interrupt.h>
436 #include <linux/major.h>
437 #include <linux/devfs_fs_kernel.h>
438 #include <linux/errno.h>
439 #include <linux/genhd.h>
440 #include <linux/slab.h>
441 #include <linux/pci.h>
442 #include <linux/ide.h>
443 #include <linux/smp_lock.h>
444 #include <linux/completion.h>
445 #include <linux/bitops.h>
446
447 #include <asm/byteorder.h>
448 #include <asm/irq.h>
449 #include <asm/uaccess.h>
450 #include <asm/io.h>
451 #include <asm/unaligned.h>
452
453 /*
454  * partition
455  */
456 typedef struct os_partition_s {
457         __u8    partition_num;
458         __u8    par_desc_ver;
459         __u16   wrt_pass_cntr;
460         __u32   first_frame_addr;
461         __u32   last_frame_addr;
462         __u32   eod_frame_addr;
463 } os_partition_t;
464
465 /*
466  * DAT entry
467  */
468 typedef struct os_dat_entry_s {
469         __u32   blk_sz;
470         __u16   blk_cnt;
471         __u8    flags;
472         __u8    reserved;
473 } os_dat_entry_t;
474
475 /*
476  * DAT
477  */
478 #define OS_DAT_FLAGS_DATA       (0xc)
479 #define OS_DAT_FLAGS_MARK       (0x1)
480
481 typedef struct os_dat_s {
482         __u8            dat_sz;
483         __u8            reserved1;
484         __u8            entry_cnt;
485         __u8            reserved3;
486         os_dat_entry_t  dat_list[16];
487 } os_dat_t;
488
489 #include <linux/mtio.h>
490
491 /**************************** Tunable parameters *****************************/
492
493
494 /*
495  *      Pipelined mode parameters.
496  *
497  *      We try to use the minimum number of stages which is enough to
498  *      keep the tape constantly streaming. To accomplish that, we implement
499  *      a feedback loop around the maximum number of stages:
500  *
501  *      We start from MIN maximum stages (we will not even use MIN stages
502  *      if we don't need them), increment it by RATE*(MAX-MIN)
503  *      whenever we sense that the pipeline is empty, until we reach
504  *      the optimum value or until we reach MAX.
505  *
506  *      Setting the following parameter to 0 is illegal: the pipelined mode
507  *      cannot be disabled (calculate_speeds() divides by tape->max_stages.)
508  */
509 #define IDETAPE_MIN_PIPELINE_STAGES       1
510 #define IDETAPE_MAX_PIPELINE_STAGES     400
511 #define IDETAPE_INCREASE_STAGES_RATE     20
512
513 /*
514  *      The following are used to debug the driver:
515  *
516  *      Setting IDETAPE_DEBUG_INFO to 1 will report device capabilities.
517  *      Setting IDETAPE_DEBUG_LOG to 1 will log driver flow control.
518  *      Setting IDETAPE_DEBUG_BUGS to 1 will enable self-sanity checks in
519  *      some places.
520  *
521  *      Setting them to 0 will restore normal operation mode:
522  *
523  *              1.      Disable logging normal successful operations.
524  *              2.      Disable self-sanity checks.
525  *              3.      Errors will still be logged, of course.
526  *
527  *      All the #if DEBUG code will be removed some day, when the driver
528  *      is verified to be stable enough. This will make it much more
529  *      esthetic.
530  */
531 #define IDETAPE_DEBUG_INFO              0
532 #define IDETAPE_DEBUG_LOG               0
533 #define IDETAPE_DEBUG_BUGS              1
534
535 /*
536  *      After each failed packet command we issue a request sense command
537  *      and retry the packet command IDETAPE_MAX_PC_RETRIES times.
538  *
539  *      Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
540  */
541 #define IDETAPE_MAX_PC_RETRIES          3
542
543 /*
544  *      With each packet command, we allocate a buffer of
545  *      IDETAPE_PC_BUFFER_SIZE bytes. This is used for several packet
546  *      commands (Not for READ/WRITE commands).
547  */
548 #define IDETAPE_PC_BUFFER_SIZE          256
549
550 /*
551  *      In various places in the driver, we need to allocate storage
552  *      for packet commands and requests, which will remain valid while
553  *      we leave the driver to wait for an interrupt or a timeout event.
554  */
555 #define IDETAPE_PC_STACK                (10 + IDETAPE_MAX_PC_RETRIES)
556
557 /*
558  * Some drives (for example, Seagate STT3401A Travan) require a very long
559  * timeout, because they don't return an interrupt or clear their busy bit
560  * until after the command completes (even retension commands).
561  */
562 #define IDETAPE_WAIT_CMD                (900*HZ)
563
564 /*
565  *      The following parameter is used to select the point in the internal
566  *      tape fifo in which we will start to refill the buffer. Decreasing
567  *      the following parameter will improve the system's latency and
568  *      interactive response, while using a high value might improve sytem
569  *      throughput.
570  */
571 #define IDETAPE_FIFO_THRESHOLD          2
572
573 /*
574  *      DSC polling parameters.
575  *
576  *      Polling for DSC (a single bit in the status register) is a very
577  *      important function in ide-tape. There are two cases in which we
578  *      poll for DSC:
579  *
580  *      1.      Before a read/write packet command, to ensure that we
581  *              can transfer data from/to the tape's data buffers, without
582  *              causing an actual media access. In case the tape is not
583  *              ready yet, we take out our request from the device
584  *              request queue, so that ide.c will service requests from
585  *              the other device on the same interface meanwhile.
586  *
587  *      2.      After the successful initialization of a "media access
588  *              packet command", which is a command which can take a long
589  *              time to complete (it can be several seconds or even an hour).
590  *
591  *              Again, we postpone our request in the middle to free the bus
592  *              for the other device. The polling frequency here should be
593  *              lower than the read/write frequency since those media access
594  *              commands are slow. We start from a "fast" frequency -
595  *              IDETAPE_DSC_MA_FAST (one second), and if we don't receive DSC
596  *              after IDETAPE_DSC_MA_THRESHOLD (5 minutes), we switch it to a
597  *              lower frequency - IDETAPE_DSC_MA_SLOW (1 minute).
598  *
599  *      We also set a timeout for the timer, in case something goes wrong.
600  *      The timeout should be longer then the maximum execution time of a
601  *      tape operation.
602  */
603  
604 /*
605  *      DSC timings.
606  */
607 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
608 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
609 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
610 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
611 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
612 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
613 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
614
615 /*************************** End of tunable parameters ***********************/
616
617 /*
618  *      Debugging/Performance analysis
619  *
620  *      I/O trace support
621  */
622 #define USE_IOTRACE     0
623 #if USE_IOTRACE
624 #include <linux/io_trace.h>
625 #define IO_IDETAPE_FIFO 500
626 #endif
627
628 /*
629  *      Read/Write error simulation
630  */
631 #define SIMULATE_ERRORS                 0
632
633 /*
634  *      For general magnetic tape device compatibility.
635  */
636 typedef enum {
637         idetape_direction_none,
638         idetape_direction_read,
639         idetape_direction_write
640 } idetape_chrdev_direction_t;
641
642 struct idetape_bh {
643         unsigned short b_size;
644         atomic_t b_count;
645         struct idetape_bh *b_reqnext;
646         char *b_data;
647 };
648
649 /*
650  *      Our view of a packet command.
651  */
652 typedef struct idetape_packet_command_s {
653         u8 c[12];                               /* Actual packet bytes */
654         int retries;                            /* On each retry, we increment retries */
655         int error;                              /* Error code */
656         int request_transfer;                   /* Bytes to transfer */
657         int actually_transferred;               /* Bytes actually transferred */
658         int buffer_size;                        /* Size of our data buffer */
659         struct idetape_bh *bh;
660         char *b_data;
661         int b_count;
662         u8 *buffer;                             /* Data buffer */
663         u8 *current_position;                   /* Pointer into the above buffer */
664         ide_startstop_t (*callback) (ide_drive_t *);    /* Called when this packet command is completed */
665         u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE];   /* Temporary buffer */
666         unsigned long flags;                    /* Status/Action bit flags: long for set_bit */
667 } idetape_pc_t;
668
669 /*
670  *      Packet command flag bits.
671  */
672 /* Set when an error is considered normal - We won't retry */
673 #define PC_ABORT                        0
674 /* 1 When polling for DSC on a media access command */
675 #define PC_WAIT_FOR_DSC                 1
676 /* 1 when we prefer to use DMA if possible */
677 #define PC_DMA_RECOMMENDED              2
678 /* 1 while DMA in progress */
679 #define PC_DMA_IN_PROGRESS              3
680 /* 1 when encountered problem during DMA */
681 #define PC_DMA_ERROR                    4
682 /* Data direction */
683 #define PC_WRITING                      5
684
685 /*
686  *      Capabilities and Mechanical Status Page
687  */
688 typedef struct {
689         unsigned        page_code       :6;     /* Page code - Should be 0x2a */
690         __u8            reserved0_6     :1;
691         __u8            ps              :1;     /* parameters saveable */
692         __u8            page_length;            /* Page Length - Should be 0x12 */
693         __u8            reserved2, reserved3;
694         unsigned        ro              :1;     /* Read Only Mode */
695         unsigned        reserved4_1234  :4;
696         unsigned        sprev           :1;     /* Supports SPACE in the reverse direction */
697         unsigned        reserved4_67    :2;
698         unsigned        reserved5_012   :3;
699         unsigned        efmt            :1;     /* Supports ERASE command initiated formatting */
700         unsigned        reserved5_4     :1;
701         unsigned        qfa             :1;     /* Supports the QFA two partition formats */
702         unsigned        reserved5_67    :2;
703         unsigned        lock            :1;     /* Supports locking the volume */
704         unsigned        locked          :1;     /* The volume is locked */
705         unsigned        prevent         :1;     /* The device defaults in the prevent state after power up */   
706         unsigned        eject           :1;     /* The device can eject the volume */
707         __u8            disconnect      :1;     /* The device can break request > ctl */        
708         __u8            reserved6_5     :1;
709         unsigned        ecc             :1;     /* Supports error correction */
710         unsigned        cmprs           :1;     /* Supports data compression */
711         unsigned        reserved7_0     :1;
712         unsigned        blk512          :1;     /* Supports 512 bytes block size */
713         unsigned        blk1024         :1;     /* Supports 1024 bytes block size */
714         unsigned        reserved7_3_6   :4;
715         unsigned        blk32768        :1;     /* slowb - the device restricts the byte count for PIO */
716                                                 /* transfers for slow buffer memory ??? */
717                                                 /* Also 32768 block size in some cases */
718         __u16           max_speed;              /* Maximum speed supported in KBps */
719         __u8            reserved10, reserved11;
720         __u16           ctl;                    /* Continuous Transfer Limit in blocks */
721         __u16           speed;                  /* Current Speed, in KBps */
722         __u16           buffer_size;            /* Buffer Size, in 512 bytes */
723         __u8            reserved18, reserved19;
724 } idetape_capabilities_page_t;
725
726 /*
727  *      Block Size Page
728  */
729 typedef struct {
730         unsigned        page_code       :6;     /* Page code - Should be 0x30 */
731         unsigned        reserved1_6     :1;
732         unsigned        ps              :1;
733         __u8            page_length;            /* Page Length - Should be 2 */
734         __u8            reserved2;
735         unsigned        play32          :1;
736         unsigned        play32_5        :1;
737         unsigned        reserved2_23    :2;
738         unsigned        record32        :1;
739         unsigned        record32_5      :1;
740         unsigned        reserved2_6     :1;
741         unsigned        one             :1;
742 } idetape_block_size_page_t;
743
744 /*
745  *      A pipeline stage.
746  */
747 typedef struct idetape_stage_s {
748         struct request rq;                      /* The corresponding request */
749         struct idetape_bh *bh;                  /* The data buffers */
750         struct idetape_stage_s *next;           /* Pointer to the next stage */
751 } idetape_stage_t;
752
753 /*
754  *      REQUEST SENSE packet command result - Data Format.
755  */
756 typedef struct {
757         unsigned        error_code      :7;     /* Current of deferred errors */
758         unsigned        valid           :1;     /* The information field conforms to QIC-157C */
759         __u8            reserved1       :8;     /* Segment Number - Reserved */
760         unsigned        sense_key       :4;     /* Sense Key */
761         unsigned        reserved2_4     :1;     /* Reserved */
762         unsigned        ili             :1;     /* Incorrect Length Indicator */
763         unsigned        eom             :1;     /* End Of Medium */
764         unsigned        filemark        :1;     /* Filemark */
765         __u32           information __attribute__ ((packed));
766         __u8            asl;                    /* Additional sense length (n-7) */
767         __u32           command_specific;       /* Additional command specific information */
768         __u8            asc;                    /* Additional Sense Code */
769         __u8            ascq;                   /* Additional Sense Code Qualifier */
770         __u8            replaceable_unit_code;  /* Field Replaceable Unit Code */
771         unsigned        sk_specific1    :7;     /* Sense Key Specific */
772         unsigned        sksv            :1;     /* Sense Key Specific information is valid */
773         __u8            sk_specific2;           /* Sense Key Specific */
774         __u8            sk_specific3;           /* Sense Key Specific */
775         __u8            pad[2];                 /* Padding to 20 bytes */
776 } idetape_request_sense_result_t;
777
778
779 /*
780  *      Most of our global data which we need to save even as we leave the
781  *      driver due to an interrupt or a timer event is stored in a variable
782  *      of type idetape_tape_t, defined below.
783  */
784 typedef struct ide_tape_obj {
785         ide_drive_t     *drive;
786         ide_driver_t    *driver;
787         struct gendisk  *disk;
788         struct kref     kref;
789
790         /*
791          *      Since a typical character device operation requires more
792          *      than one packet command, we provide here enough memory
793          *      for the maximum of interconnected packet commands.
794          *      The packet commands are stored in the circular array pc_stack.
795          *      pc_stack_index points to the last used entry, and warps around
796          *      to the start when we get to the last array entry.
797          *
798          *      pc points to the current processed packet command.
799          *
800          *      failed_pc points to the last failed packet command, or contains
801          *      NULL if we do not need to retry any packet command. This is
802          *      required since an additional packet command is needed before the
803          *      retry, to get detailed information on what went wrong.
804          */
805         /* Current packet command */
806         idetape_pc_t *pc;
807         /* Last failed packet command */
808         idetape_pc_t *failed_pc;
809         /* Packet command stack */
810         idetape_pc_t pc_stack[IDETAPE_PC_STACK];
811         /* Next free packet command storage space */
812         int pc_stack_index;
813         struct request rq_stack[IDETAPE_PC_STACK];
814         /* We implement a circular array */
815         int rq_stack_index;
816
817         /*
818          *      DSC polling variables.
819          *
820          *      While polling for DSC we use postponed_rq to postpone the
821          *      current request so that ide.c will be able to service
822          *      pending requests on the other device. Note that at most
823          *      we will have only one DSC (usually data transfer) request
824          *      in the device request queue. Additional requests can be
825          *      queued in our internal pipeline, but they will be visible
826          *      to ide.c only one at a time.
827          */
828         struct request *postponed_rq;
829         /* The time in which we started polling for DSC */
830         unsigned long dsc_polling_start;
831         /* Timer used to poll for dsc */
832         struct timer_list dsc_timer;
833         /* Read/Write dsc polling frequency */
834         unsigned long best_dsc_rw_frequency;
835         /* The current polling frequency */
836         unsigned long dsc_polling_frequency;
837         /* Maximum waiting time */
838         unsigned long dsc_timeout;
839
840         /*
841          *      Read position information
842          */
843         u8 partition;
844         /* Current block */
845         unsigned int first_frame_position;
846         unsigned int last_frame_position;
847         unsigned int blocks_in_buffer;
848
849         /*
850          *      Last error information
851          */
852         u8 sense_key, asc, ascq;
853
854         /*
855          *      Character device operation
856          */
857         unsigned int minor;
858         /* device name */
859         char name[4];
860         /* Current character device data transfer direction */
861         idetape_chrdev_direction_t chrdev_direction;
862
863         /*
864          *      Device information
865          */
866         /* Usually 512 or 1024 bytes */
867         unsigned short tape_block_size;
868         int user_bs_factor;
869         /* Copy of the tape's Capabilities and Mechanical Page */
870         idetape_capabilities_page_t capabilities;
871
872         /*
873          *      Active data transfer request parameters.
874          *
875          *      At most, there is only one ide-tape originated data transfer
876          *      request in the device request queue. This allows ide.c to
877          *      easily service requests from the other device when we
878          *      postpone our active request. In the pipelined operation
879          *      mode, we use our internal pipeline structure to hold
880          *      more data requests.
881          *
882          *      The data buffer size is chosen based on the tape's
883          *      recommendation.
884          */
885         /* Pointer to the request which is waiting in the device request queue */
886         struct request *active_data_request;
887         /* Data buffer size (chosen based on the tape's recommendation */
888         int stage_size;
889         idetape_stage_t *merge_stage;
890         int merge_stage_size;
891         struct idetape_bh *bh;
892         char *b_data;
893         int b_count;
894         
895         /*
896          *      Pipeline parameters.
897          *
898          *      To accomplish non-pipelined mode, we simply set the following
899          *      variables to zero (or NULL, where appropriate).
900          */
901         /* Number of currently used stages */
902         int nr_stages;
903         /* Number of pending stages */
904         int nr_pending_stages;
905         /* We will not allocate more than this number of stages */
906         int max_stages, min_pipeline, max_pipeline;
907         /* The first stage which will be removed from the pipeline */
908         idetape_stage_t *first_stage;
909         /* The currently active stage */
910         idetape_stage_t *active_stage;
911         /* Will be serviced after the currently active request */
912         idetape_stage_t *next_stage;
913         /* New requests will be added to the pipeline here */
914         idetape_stage_t *last_stage;
915         /* Optional free stage which we can use */
916         idetape_stage_t *cache_stage;
917         int pages_per_stage;
918         /* Wasted space in each stage */
919         int excess_bh_size;
920
921         /* Status/Action flags: long for set_bit */
922         unsigned long flags;
923         /* protects the ide-tape queue */
924         spinlock_t spinlock;
925
926         /*
927          * Measures average tape speed
928          */
929         unsigned long avg_time;
930         int avg_size;
931         int avg_speed;
932
933         /* last sense information */
934         idetape_request_sense_result_t sense;
935
936         char vendor_id[10];
937         char product_id[18];
938         char firmware_revision[6];
939         int firmware_revision_num;
940
941         /* the door is currently locked */
942         int door_locked;
943         /* the tape hardware is write protected */
944         char drv_write_prot;
945         /* the tape is write protected (hardware or opened as read-only) */
946         char write_prot;
947
948         /*
949          * Limit the number of times a request can
950          * be postponed, to avoid an infinite postpone
951          * deadlock.
952          */
953         /* request postpone count limit */
954         int postpone_cnt;
955
956         /*
957          * Measures number of frames:
958          *
959          * 1. written/read to/from the driver pipeline (pipeline_head).
960          * 2. written/read to/from the tape buffers (idetape_bh).
961          * 3. written/read by the tape to/from the media (tape_head).
962          */
963         int pipeline_head;
964         int buffer_head;
965         int tape_head;
966         int last_tape_head;
967
968         /*
969          * Speed control at the tape buffers input/output
970          */
971         unsigned long insert_time;
972         int insert_size;
973         int insert_speed;
974         int max_insert_speed;
975         int measure_insert_time;
976
977         /*
978          * Measure tape still time, in milliseconds
979          */
980         unsigned long tape_still_time_begin;
981         int tape_still_time;
982
983         /*
984          * Speed regulation negative feedback loop
985          */
986         int speed_control;
987         int pipeline_head_speed;
988         int controlled_pipeline_head_speed;
989         int uncontrolled_pipeline_head_speed;
990         int controlled_last_pipeline_head;
991         int uncontrolled_last_pipeline_head;
992         unsigned long uncontrolled_pipeline_head_time;
993         unsigned long controlled_pipeline_head_time;
994         int controlled_previous_pipeline_head;
995         int uncontrolled_previous_pipeline_head;
996         unsigned long controlled_previous_head_time;
997         unsigned long uncontrolled_previous_head_time;
998         int restart_speed_control_req;
999
1000         /*
1001          * Debug_level determines amount of debugging output;
1002          * can be changed using /proc/ide/hdx/settings
1003          * 0 : almost no debugging output
1004          * 1 : 0+output errors only
1005          * 2 : 1+output all sensekey/asc
1006          * 3 : 2+follow all chrdev related procedures
1007          * 4 : 3+follow all procedures
1008          * 5 : 4+include pc_stack rq_stack info
1009          * 6 : 5+USE_COUNT updates
1010          */
1011          int debug_level; 
1012 } idetape_tape_t;
1013
1014 static DECLARE_MUTEX(idetape_ref_sem);
1015
1016 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
1017
1018 #define ide_tape_g(disk) \
1019         container_of((disk)->private_data, struct ide_tape_obj, driver)
1020
1021 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
1022 {
1023         struct ide_tape_obj *tape = NULL;
1024
1025         down(&idetape_ref_sem);
1026         tape = ide_tape_g(disk);
1027         if (tape)
1028                 kref_get(&tape->kref);
1029         up(&idetape_ref_sem);
1030         return tape;
1031 }
1032
1033 static void ide_tape_release(struct kref *);
1034
1035 static void ide_tape_put(struct ide_tape_obj *tape)
1036 {
1037         down(&idetape_ref_sem);
1038         kref_put(&tape->kref, ide_tape_release);
1039         up(&idetape_ref_sem);
1040 }
1041
1042 /*
1043  *      Tape door status
1044  */
1045 #define DOOR_UNLOCKED                   0
1046 #define DOOR_LOCKED                     1
1047 #define DOOR_EXPLICITLY_LOCKED          2
1048
1049 /*
1050  *      Tape flag bits values.
1051  */
1052 #define IDETAPE_IGNORE_DSC              0
1053 #define IDETAPE_ADDRESS_VALID           1       /* 0 When the tape position is unknown */
1054 #define IDETAPE_BUSY                    2       /* Device already opened */
1055 #define IDETAPE_PIPELINE_ERROR          3       /* Error detected in a pipeline stage */
1056 #define IDETAPE_DETECT_BS               4       /* Attempt to auto-detect the current user block size */
1057 #define IDETAPE_FILEMARK                5       /* Currently on a filemark */
1058 #define IDETAPE_DRQ_INTERRUPT           6       /* DRQ interrupt device */
1059 #define IDETAPE_READ_ERROR              7
1060 #define IDETAPE_PIPELINE_ACTIVE         8       /* pipeline active */
1061 /* 0 = no tape is loaded, so we don't rewind after ejecting */
1062 #define IDETAPE_MEDIUM_PRESENT          9
1063
1064 /*
1065  *      Supported ATAPI tape drives packet commands
1066  */
1067 #define IDETAPE_TEST_UNIT_READY_CMD     0x00
1068 #define IDETAPE_REWIND_CMD              0x01
1069 #define IDETAPE_REQUEST_SENSE_CMD       0x03
1070 #define IDETAPE_READ_CMD                0x08
1071 #define IDETAPE_WRITE_CMD               0x0a
1072 #define IDETAPE_WRITE_FILEMARK_CMD      0x10
1073 #define IDETAPE_SPACE_CMD               0x11
1074 #define IDETAPE_INQUIRY_CMD             0x12
1075 #define IDETAPE_ERASE_CMD               0x19
1076 #define IDETAPE_MODE_SENSE_CMD          0x1a
1077 #define IDETAPE_MODE_SELECT_CMD         0x15
1078 #define IDETAPE_LOAD_UNLOAD_CMD         0x1b
1079 #define IDETAPE_PREVENT_CMD             0x1e
1080 #define IDETAPE_LOCATE_CMD              0x2b
1081 #define IDETAPE_READ_POSITION_CMD       0x34
1082 #define IDETAPE_READ_BUFFER_CMD         0x3c
1083 #define IDETAPE_SET_SPEED_CMD           0xbb
1084
1085 /*
1086  *      Some defines for the READ BUFFER command
1087  */
1088 #define IDETAPE_RETRIEVE_FAULTY_BLOCK   6
1089
1090 /*
1091  *      Some defines for the SPACE command
1092  */
1093 #define IDETAPE_SPACE_OVER_FILEMARK     1
1094 #define IDETAPE_SPACE_TO_EOD            3
1095
1096 /*
1097  *      Some defines for the LOAD UNLOAD command
1098  */
1099 #define IDETAPE_LU_LOAD_MASK            1
1100 #define IDETAPE_LU_RETENSION_MASK       2
1101 #define IDETAPE_LU_EOT_MASK             4
1102
1103 /*
1104  *      Special requests for our block device strategy routine.
1105  *
1106  *      In order to service a character device command, we add special
1107  *      requests to the tail of our block device request queue and wait
1108  *      for their completion.
1109  */
1110
1111 enum {
1112         REQ_IDETAPE_PC1         = (1 << 0), /* packet command (first stage) */
1113         REQ_IDETAPE_PC2         = (1 << 1), /* packet command (second stage) */
1114         REQ_IDETAPE_READ        = (1 << 2),
1115         REQ_IDETAPE_WRITE       = (1 << 3),
1116         REQ_IDETAPE_READ_BUFFER = (1 << 4),
1117 };
1118
1119 /*
1120  *      Error codes which are returned in rq->errors to the higher part
1121  *      of the driver.
1122  */
1123 #define IDETAPE_ERROR_GENERAL           101
1124 #define IDETAPE_ERROR_FILEMARK          102
1125 #define IDETAPE_ERROR_EOD               103
1126
1127 /*
1128  *      The following is used to format the general configuration word of
1129  *      the ATAPI IDENTIFY DEVICE command.
1130  */
1131 struct idetape_id_gcw { 
1132         unsigned packet_size            :2;     /* Packet Size */
1133         unsigned reserved234            :3;     /* Reserved */
1134         unsigned drq_type               :2;     /* Command packet DRQ type */
1135         unsigned removable              :1;     /* Removable media */
1136         unsigned device_type            :5;     /* Device type */
1137         unsigned reserved13             :1;     /* Reserved */
1138         unsigned protocol               :2;     /* Protocol type */
1139 };
1140
1141 /*
1142  *      INQUIRY packet command - Data Format (From Table 6-8 of QIC-157C)
1143  */
1144 typedef struct {
1145         unsigned        device_type     :5;     /* Peripheral Device Type */
1146         unsigned        reserved0_765   :3;     /* Peripheral Qualifier - Reserved */
1147         unsigned        reserved1_6t0   :7;     /* Reserved */
1148         unsigned        rmb             :1;     /* Removable Medium Bit */
1149         unsigned        ansi_version    :3;     /* ANSI Version */
1150         unsigned        ecma_version    :3;     /* ECMA Version */
1151         unsigned        iso_version     :2;     /* ISO Version */
1152         unsigned        response_format :4;     /* Response Data Format */
1153         unsigned        reserved3_45    :2;     /* Reserved */
1154         unsigned        reserved3_6     :1;     /* TrmIOP - Reserved */
1155         unsigned        reserved3_7     :1;     /* AENC - Reserved */
1156         __u8            additional_length;      /* Additional Length (total_length-4) */
1157         __u8            rsv5, rsv6, rsv7;       /* Reserved */
1158         __u8            vendor_id[8];           /* Vendor Identification */
1159         __u8            product_id[16];         /* Product Identification */
1160         __u8            revision_level[4];      /* Revision Level */
1161         __u8            vendor_specific[20];    /* Vendor Specific - Optional */
1162         __u8            reserved56t95[40];      /* Reserved - Optional */
1163                                                 /* Additional information may be returned */
1164 } idetape_inquiry_result_t;
1165
1166 /*
1167  *      READ POSITION packet command - Data Format (From Table 6-57)
1168  */
1169 typedef struct {
1170         unsigned        reserved0_10    :2;     /* Reserved */
1171         unsigned        bpu             :1;     /* Block Position Unknown */    
1172         unsigned        reserved0_543   :3;     /* Reserved */
1173         unsigned        eop             :1;     /* End Of Partition */
1174         unsigned        bop             :1;     /* Beginning Of Partition */
1175         u8              partition;              /* Partition Number */
1176         u8              reserved2, reserved3;   /* Reserved */
1177         u32             first_block;            /* First Block Location */
1178         u32             last_block;             /* Last Block Location (Optional) */
1179         u8              reserved12;             /* Reserved */
1180         u8              blocks_in_buffer[3];    /* Blocks In Buffer - (Optional) */
1181         u32             bytes_in_buffer;        /* Bytes In Buffer (Optional) */
1182 } idetape_read_position_result_t;
1183
1184 /*
1185  *      Follows structures which are related to the SELECT SENSE / MODE SENSE
1186  *      packet commands. Those packet commands are still not supported
1187  *      by ide-tape.
1188  */
1189 #define IDETAPE_BLOCK_DESCRIPTOR        0
1190 #define IDETAPE_CAPABILITIES_PAGE       0x2a
1191 #define IDETAPE_PARAMTR_PAGE            0x2b   /* Onstream DI-x0 only */
1192 #define IDETAPE_BLOCK_SIZE_PAGE         0x30
1193 #define IDETAPE_BUFFER_FILLING_PAGE     0x33
1194
1195 /*
1196  *      Mode Parameter Header for the MODE SENSE packet command
1197  */
1198 typedef struct {
1199         __u8    mode_data_length;       /* Length of the following data transfer */
1200         __u8    medium_type;            /* Medium Type */
1201         __u8    dsp;                    /* Device Specific Parameter */
1202         __u8    bdl;                    /* Block Descriptor Length */
1203 #if 0
1204         /* data transfer page */
1205         __u8    page_code       :6;
1206         __u8    reserved0_6     :1;
1207         __u8    ps              :1;     /* parameters saveable */
1208         __u8    page_length;            /* page Length == 0x02 */
1209         __u8    reserved2;
1210         __u8    read32k         :1;     /* 32k blk size (data only) */
1211         __u8    read32k5        :1;     /* 32.5k blk size (data&AUX) */
1212         __u8    reserved3_23    :2;
1213         __u8    write32k        :1;     /* 32k blk size (data only) */
1214         __u8    write32k5       :1;     /* 32.5k blk size (data&AUX) */
1215         __u8    reserved3_6     :1;
1216         __u8    streaming       :1;     /* streaming mode enable */
1217 #endif
1218 } idetape_mode_parameter_header_t;
1219
1220 /*
1221  *      Mode Parameter Block Descriptor the MODE SENSE packet command
1222  *
1223  *      Support for block descriptors is optional.
1224  */
1225 typedef struct {
1226         __u8            density_code;           /* Medium density code */
1227         __u8            blocks[3];              /* Number of blocks */
1228         __u8            reserved4;              /* Reserved */
1229         __u8            length[3];              /* Block Length */
1230 } idetape_parameter_block_descriptor_t;
1231
1232 /*
1233  *      The Data Compression Page, as returned by the MODE SENSE packet command.
1234  */
1235 typedef struct {
1236         unsigned        page_code       :6;     /* Page Code - Should be 0xf */
1237         unsigned        reserved0       :1;     /* Reserved */
1238         unsigned        ps              :1;
1239         __u8            page_length;            /* Page Length - Should be 14 */
1240         unsigned        reserved2       :6;     /* Reserved */
1241         unsigned        dcc             :1;     /* Data Compression Capable */
1242         unsigned        dce             :1;     /* Data Compression Enable */
1243         unsigned        reserved3       :5;     /* Reserved */
1244         unsigned        red             :2;     /* Report Exception on Decompression */
1245         unsigned        dde             :1;     /* Data Decompression Enable */
1246         __u32           ca;                     /* Compression Algorithm */
1247         __u32           da;                     /* Decompression Algorithm */
1248         __u8            reserved[4];            /* Reserved */
1249 } idetape_data_compression_page_t;
1250
1251 /*
1252  *      The Medium Partition Page, as returned by the MODE SENSE packet command.
1253  */
1254 typedef struct {
1255         unsigned        page_code       :6;     /* Page Code - Should be 0x11 */
1256         unsigned        reserved1_6     :1;     /* Reserved */
1257         unsigned        ps              :1;
1258         __u8            page_length;            /* Page Length - Should be 6 */
1259         __u8            map;                    /* Maximum Additional Partitions - Should be 0 */
1260         __u8            apd;                    /* Additional Partitions Defined - Should be 0 */
1261         unsigned        reserved4_012   :3;     /* Reserved */
1262         unsigned        psum            :2;     /* Should be 0 */
1263         unsigned        idp             :1;     /* Should be 0 */
1264         unsigned        sdp             :1;     /* Should be 0 */
1265         unsigned        fdp             :1;     /* Fixed Data Partitions */
1266         __u8            mfr;                    /* Medium Format Recognition */
1267         __u8            reserved[2];            /* Reserved */
1268 } idetape_medium_partition_page_t;
1269
1270 /*
1271  *      Run time configurable parameters.
1272  */
1273 typedef struct {
1274         int     dsc_rw_frequency;
1275         int     dsc_media_access_frequency;
1276         int     nr_stages;
1277 } idetape_config_t;
1278
1279 /*
1280  *      The variables below are used for the character device interface.
1281  *      Additional state variables are defined in our ide_drive_t structure.
1282  */
1283 static struct ide_tape_obj * idetape_devs[MAX_HWIFS * MAX_DRIVES];
1284
1285 #define ide_tape_f(file) ((file)->private_data)
1286
1287 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
1288 {
1289         struct ide_tape_obj *tape = NULL;
1290
1291         down(&idetape_ref_sem);
1292         tape = idetape_devs[i];
1293         if (tape)
1294                 kref_get(&tape->kref);
1295         up(&idetape_ref_sem);
1296         return tape;
1297 }
1298
1299 /*
1300  *      Function declarations
1301  *
1302  */
1303 static int idetape_chrdev_release (struct inode *inode, struct file *filp);
1304 static void idetape_write_release (ide_drive_t *drive, unsigned int minor);
1305
1306 /*
1307  * Too bad. The drive wants to send us data which we are not ready to accept.
1308  * Just throw it away.
1309  */
1310 static void idetape_discard_data (ide_drive_t *drive, unsigned int bcount)
1311 {
1312         while (bcount--)
1313                 (void) HWIF(drive)->INB(IDE_DATA_REG);
1314 }
1315
1316 static void idetape_input_buffers (ide_drive_t *drive, idetape_pc_t *pc, unsigned int bcount)
1317 {
1318         struct idetape_bh *bh = pc->bh;
1319         int count;
1320
1321         while (bcount) {
1322 #if IDETAPE_DEBUG_BUGS
1323                 if (bh == NULL) {
1324                         printk(KERN_ERR "ide-tape: bh == NULL in "
1325                                 "idetape_input_buffers\n");
1326                         idetape_discard_data(drive, bcount);
1327                         return;
1328                 }
1329 #endif /* IDETAPE_DEBUG_BUGS */
1330                 count = min((unsigned int)(bh->b_size - atomic_read(&bh->b_count)), bcount);
1331                 HWIF(drive)->atapi_input_bytes(drive, bh->b_data + atomic_read(&bh->b_count), count);
1332                 bcount -= count;
1333                 atomic_add(count, &bh->b_count);
1334                 if (atomic_read(&bh->b_count) == bh->b_size) {
1335                         bh = bh->b_reqnext;
1336                         if (bh)
1337                                 atomic_set(&bh->b_count, 0);
1338                 }
1339         }
1340         pc->bh = bh;
1341 }
1342
1343 static void idetape_output_buffers (ide_drive_t *drive, idetape_pc_t *pc, unsigned int bcount)
1344 {
1345         struct idetape_bh *bh = pc->bh;
1346         int count;
1347
1348         while (bcount) {
1349 #if IDETAPE_DEBUG_BUGS
1350                 if (bh == NULL) {
1351                         printk(KERN_ERR "ide-tape: bh == NULL in "
1352                                 "idetape_output_buffers\n");
1353                         return;
1354                 }
1355 #endif /* IDETAPE_DEBUG_BUGS */
1356                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
1357                 HWIF(drive)->atapi_output_bytes(drive, pc->b_data, count);
1358                 bcount -= count;
1359                 pc->b_data += count;
1360                 pc->b_count -= count;
1361                 if (!pc->b_count) {
1362                         pc->bh = bh = bh->b_reqnext;
1363                         if (bh) {
1364                                 pc->b_data = bh->b_data;
1365                                 pc->b_count = atomic_read(&bh->b_count);
1366                         }
1367                 }
1368         }
1369 }
1370
1371 static void idetape_update_buffers (idetape_pc_t *pc)
1372 {
1373         struct idetape_bh *bh = pc->bh;
1374         int count;
1375         unsigned int bcount = pc->actually_transferred;
1376
1377         if (test_bit(PC_WRITING, &pc->flags))
1378                 return;
1379         while (bcount) {
1380 #if IDETAPE_DEBUG_BUGS
1381                 if (bh == NULL) {
1382                         printk(KERN_ERR "ide-tape: bh == NULL in "
1383                                 "idetape_update_buffers\n");
1384                         return;
1385                 }
1386 #endif /* IDETAPE_DEBUG_BUGS */
1387                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
1388                 atomic_set(&bh->b_count, count);
1389                 if (atomic_read(&bh->b_count) == bh->b_size)
1390                         bh = bh->b_reqnext;
1391                 bcount -= count;
1392         }
1393         pc->bh = bh;
1394 }
1395
1396 /*
1397  *      idetape_next_pc_storage returns a pointer to a place in which we can
1398  *      safely store a packet command, even though we intend to leave the
1399  *      driver. A storage space for a maximum of IDETAPE_PC_STACK packet
1400  *      commands is allocated at initialization time.
1401  */
1402 static idetape_pc_t *idetape_next_pc_storage (ide_drive_t *drive)
1403 {
1404         idetape_tape_t *tape = drive->driver_data;
1405
1406 #if IDETAPE_DEBUG_LOG
1407         if (tape->debug_level >= 5)
1408                 printk(KERN_INFO "ide-tape: pc_stack_index=%d\n",
1409                         tape->pc_stack_index);
1410 #endif /* IDETAPE_DEBUG_LOG */
1411         if (tape->pc_stack_index == IDETAPE_PC_STACK)
1412                 tape->pc_stack_index=0;
1413         return (&tape->pc_stack[tape->pc_stack_index++]);
1414 }
1415
1416 /*
1417  *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
1418  *      Since we queue packet commands in the request queue, we need to
1419  *      allocate a request, along with the allocation of a packet command.
1420  */
1421  
1422 /**************************************************************
1423  *                                                            *
1424  *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
1425  *  followed later on by kfree().   -ml                       *
1426  *                                                            *
1427  **************************************************************/
1428  
1429 static struct request *idetape_next_rq_storage (ide_drive_t *drive)
1430 {
1431         idetape_tape_t *tape = drive->driver_data;
1432
1433 #if IDETAPE_DEBUG_LOG
1434         if (tape->debug_level >= 5)
1435                 printk(KERN_INFO "ide-tape: rq_stack_index=%d\n",
1436                         tape->rq_stack_index);
1437 #endif /* IDETAPE_DEBUG_LOG */
1438         if (tape->rq_stack_index == IDETAPE_PC_STACK)
1439                 tape->rq_stack_index=0;
1440         return (&tape->rq_stack[tape->rq_stack_index++]);
1441 }
1442
1443 /*
1444  *      idetape_init_pc initializes a packet command.
1445  */
1446 static void idetape_init_pc (idetape_pc_t *pc)
1447 {
1448         memset(pc->c, 0, 12);
1449         pc->retries = 0;
1450         pc->flags = 0;
1451         pc->request_transfer = 0;
1452         pc->buffer = pc->pc_buffer;
1453         pc->buffer_size = IDETAPE_PC_BUFFER_SIZE;
1454         pc->bh = NULL;
1455         pc->b_data = NULL;
1456 }
1457
1458 /*
1459  *      idetape_analyze_error is called on each failed packet command retry
1460  *      to analyze the request sense. We currently do not utilize this
1461  *      information.
1462  */
1463 static void idetape_analyze_error (ide_drive_t *drive, idetape_request_sense_result_t *result)
1464 {
1465         idetape_tape_t *tape = drive->driver_data;
1466         idetape_pc_t *pc = tape->failed_pc;
1467
1468         tape->sense     = *result;
1469         tape->sense_key = result->sense_key;
1470         tape->asc       = result->asc;
1471         tape->ascq      = result->ascq;
1472 #if IDETAPE_DEBUG_LOG
1473         /*
1474          *      Without debugging, we only log an error if we decided to
1475          *      give up retrying.
1476          */
1477         if (tape->debug_level >= 1)
1478                 printk(KERN_INFO "ide-tape: pc = %x, sense key = %x, "
1479                         "asc = %x, ascq = %x\n",
1480                         pc->c[0], result->sense_key,
1481                         result->asc, result->ascq);
1482 #endif /* IDETAPE_DEBUG_LOG */
1483
1484         /*
1485          *      Correct pc->actually_transferred by asking the tape.
1486          */
1487         if (test_bit(PC_DMA_ERROR, &pc->flags)) {
1488                 pc->actually_transferred = pc->request_transfer - tape->tape_block_size * ntohl(get_unaligned(&result->information));
1489                 idetape_update_buffers(pc);
1490         }
1491
1492         /*
1493          * If error was the result of a zero-length read or write command,
1494          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
1495          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
1496          */
1497         if ((pc->c[0] == IDETAPE_READ_CMD || pc->c[0] == IDETAPE_WRITE_CMD)
1498             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) { /* length==0 */
1499                 if (result->sense_key == 5) {
1500                         /* don't report an error, everything's ok */
1501                         pc->error = 0;
1502                         /* don't retry read/write */
1503                         set_bit(PC_ABORT, &pc->flags);
1504                 }
1505         }
1506         if (pc->c[0] == IDETAPE_READ_CMD && result->filemark) {
1507                 pc->error = IDETAPE_ERROR_FILEMARK;
1508                 set_bit(PC_ABORT, &pc->flags);
1509         }
1510         if (pc->c[0] == IDETAPE_WRITE_CMD) {
1511                 if (result->eom ||
1512                     (result->sense_key == 0xd && result->asc == 0x0 &&
1513                      result->ascq == 0x2)) {
1514                         pc->error = IDETAPE_ERROR_EOD;
1515                         set_bit(PC_ABORT, &pc->flags);
1516                 }
1517         }
1518         if (pc->c[0] == IDETAPE_READ_CMD || pc->c[0] == IDETAPE_WRITE_CMD) {
1519                 if (result->sense_key == 8) {
1520                         pc->error = IDETAPE_ERROR_EOD;
1521                         set_bit(PC_ABORT, &pc->flags);
1522                 }
1523                 if (!test_bit(PC_ABORT, &pc->flags) &&
1524                     pc->actually_transferred)
1525                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
1526         }
1527 }
1528
1529 /*
1530  * idetape_active_next_stage will declare the next stage as "active".
1531  */
1532 static void idetape_active_next_stage (ide_drive_t *drive)
1533 {
1534         idetape_tape_t *tape = drive->driver_data;
1535         idetape_stage_t *stage = tape->next_stage;
1536         struct request *rq = &stage->rq;
1537
1538 #if IDETAPE_DEBUG_LOG
1539         if (tape->debug_level >= 4)
1540                 printk(KERN_INFO "ide-tape: Reached idetape_active_next_stage\n");
1541 #endif /* IDETAPE_DEBUG_LOG */
1542 #if IDETAPE_DEBUG_BUGS
1543         if (stage == NULL) {
1544                 printk(KERN_ERR "ide-tape: bug: Trying to activate a non existing stage\n");
1545                 return;
1546         }
1547 #endif /* IDETAPE_DEBUG_BUGS */ 
1548
1549         rq->rq_disk = tape->disk;
1550         rq->buffer = NULL;
1551         rq->special = (void *)stage->bh;
1552         tape->active_data_request = rq;
1553         tape->active_stage = stage;
1554         tape->next_stage = stage->next;
1555 }
1556
1557 /*
1558  *      idetape_increase_max_pipeline_stages is a part of the feedback
1559  *      loop which tries to find the optimum number of stages. In the
1560  *      feedback loop, we are starting from a minimum maximum number of
1561  *      stages, and if we sense that the pipeline is empty, we try to
1562  *      increase it, until we reach the user compile time memory limit.
1563  */
1564 static void idetape_increase_max_pipeline_stages (ide_drive_t *drive)
1565 {
1566         idetape_tape_t *tape = drive->driver_data;
1567         int increase = (tape->max_pipeline - tape->min_pipeline) / 10;
1568         
1569 #if IDETAPE_DEBUG_LOG
1570         if (tape->debug_level >= 4)
1571                 printk (KERN_INFO "ide-tape: Reached idetape_increase_max_pipeline_stages\n");
1572 #endif /* IDETAPE_DEBUG_LOG */
1573
1574         tape->max_stages += max(increase, 1);
1575         tape->max_stages = max(tape->max_stages, tape->min_pipeline);
1576         tape->max_stages = min(tape->max_stages, tape->max_pipeline);
1577 }
1578
1579 /*
1580  *      idetape_kfree_stage calls kfree to completely free a stage, along with
1581  *      its related buffers.
1582  */
1583 static void __idetape_kfree_stage (idetape_stage_t *stage)
1584 {
1585         struct idetape_bh *prev_bh, *bh = stage->bh;
1586         int size;
1587
1588         while (bh != NULL) {
1589                 if (bh->b_data != NULL) {
1590                         size = (int) bh->b_size;
1591                         while (size > 0) {
1592                                 free_page((unsigned long) bh->b_data);
1593                                 size -= PAGE_SIZE;
1594                                 bh->b_data += PAGE_SIZE;
1595                         }
1596                 }
1597                 prev_bh = bh;
1598                 bh = bh->b_reqnext;
1599                 kfree(prev_bh);
1600         }
1601         kfree(stage);
1602 }
1603
1604 static void idetape_kfree_stage (idetape_tape_t *tape, idetape_stage_t *stage)
1605 {
1606         __idetape_kfree_stage(stage);
1607 }
1608
1609 /*
1610  *      idetape_remove_stage_head removes tape->first_stage from the pipeline.
1611  *      The caller should avoid race conditions.
1612  */
1613 static void idetape_remove_stage_head (ide_drive_t *drive)
1614 {
1615         idetape_tape_t *tape = drive->driver_data;
1616         idetape_stage_t *stage;
1617         
1618 #if IDETAPE_DEBUG_LOG
1619         if (tape->debug_level >= 4)
1620                 printk(KERN_INFO "ide-tape: Reached idetape_remove_stage_head\n");
1621 #endif /* IDETAPE_DEBUG_LOG */
1622 #if IDETAPE_DEBUG_BUGS
1623         if (tape->first_stage == NULL) {
1624                 printk(KERN_ERR "ide-tape: bug: tape->first_stage is NULL\n");
1625                 return;         
1626         }
1627         if (tape->active_stage == tape->first_stage) {
1628                 printk(KERN_ERR "ide-tape: bug: Trying to free our active pipeline stage\n");
1629                 return;
1630         }
1631 #endif /* IDETAPE_DEBUG_BUGS */
1632         stage = tape->first_stage;
1633         tape->first_stage = stage->next;
1634         idetape_kfree_stage(tape, stage);
1635         tape->nr_stages--;
1636         if (tape->first_stage == NULL) {
1637                 tape->last_stage = NULL;
1638 #if IDETAPE_DEBUG_BUGS
1639                 if (tape->next_stage != NULL)
1640                         printk(KERN_ERR "ide-tape: bug: tape->next_stage != NULL\n");
1641                 if (tape->nr_stages)
1642                         printk(KERN_ERR "ide-tape: bug: nr_stages should be 0 now\n");
1643 #endif /* IDETAPE_DEBUG_BUGS */
1644         }
1645 }
1646
1647 /*
1648  * This will free all the pipeline stages starting from new_last_stage->next
1649  * to the end of the list, and point tape->last_stage to new_last_stage.
1650  */
1651 static void idetape_abort_pipeline(ide_drive_t *drive,
1652                                    idetape_stage_t *new_last_stage)
1653 {
1654         idetape_tape_t *tape = drive->driver_data;
1655         idetape_stage_t *stage = new_last_stage->next;
1656         idetape_stage_t *nstage;
1657
1658 #if IDETAPE_DEBUG_LOG
1659         if (tape->debug_level >= 4)
1660                 printk(KERN_INFO "ide-tape: %s: idetape_abort_pipeline called\n", tape->name);
1661 #endif
1662         while (stage) {
1663                 nstage = stage->next;
1664                 idetape_kfree_stage(tape, stage);
1665                 --tape->nr_stages;
1666                 --tape->nr_pending_stages;
1667                 stage = nstage;
1668         }
1669         if (new_last_stage)
1670                 new_last_stage->next = NULL;
1671         tape->last_stage = new_last_stage;
1672         tape->next_stage = NULL;
1673 }
1674
1675 /*
1676  *      idetape_end_request is used to finish servicing a request, and to
1677  *      insert a pending pipeline request into the main device queue.
1678  */
1679 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
1680 {
1681         struct request *rq = HWGROUP(drive)->rq;
1682         idetape_tape_t *tape = drive->driver_data;
1683         unsigned long flags;
1684         int error;
1685         int remove_stage = 0;
1686         idetape_stage_t *active_stage;
1687
1688 #if IDETAPE_DEBUG_LOG
1689         if (tape->debug_level >= 4)
1690         printk(KERN_INFO "ide-tape: Reached idetape_end_request\n");
1691 #endif /* IDETAPE_DEBUG_LOG */
1692
1693         switch (uptodate) {
1694                 case 0: error = IDETAPE_ERROR_GENERAL; break;
1695                 case 1: error = 0; break;
1696                 default: error = uptodate;
1697         }
1698         rq->errors = error;
1699         if (error)
1700                 tape->failed_pc = NULL;
1701
1702         spin_lock_irqsave(&tape->spinlock, flags);
1703
1704         /* The request was a pipelined data transfer request */
1705         if (tape->active_data_request == rq) {
1706                 active_stage = tape->active_stage;
1707                 tape->active_stage = NULL;
1708                 tape->active_data_request = NULL;
1709                 tape->nr_pending_stages--;
1710                 if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
1711                         remove_stage = 1;
1712                         if (error) {
1713                                 set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
1714                                 if (error == IDETAPE_ERROR_EOD)
1715                                         idetape_abort_pipeline(drive, active_stage);
1716                         }
1717                 } else if (rq->cmd[0] & REQ_IDETAPE_READ) {
1718                         if (error == IDETAPE_ERROR_EOD) {
1719                                 set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
1720                                 idetape_abort_pipeline(drive, active_stage);
1721                         }
1722                 }
1723                 if (tape->next_stage != NULL) {
1724                         idetape_active_next_stage(drive);
1725
1726                         /*
1727                          * Insert the next request into the request queue.
1728                          */
1729                         (void) ide_do_drive_cmd(drive, tape->active_data_request, ide_end);
1730                 } else if (!error) {
1731                                 idetape_increase_max_pipeline_stages(drive);
1732                 }
1733         }
1734         ide_end_drive_cmd(drive, 0, 0);
1735 //      blkdev_dequeue_request(rq);
1736 //      drive->rq = NULL;
1737 //      end_that_request_last(rq);
1738
1739         if (remove_stage)
1740                 idetape_remove_stage_head(drive);
1741         if (tape->active_data_request == NULL)
1742                 clear_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
1743         spin_unlock_irqrestore(&tape->spinlock, flags);
1744         return 0;
1745 }
1746
1747 static ide_startstop_t idetape_request_sense_callback (ide_drive_t *drive)
1748 {
1749         idetape_tape_t *tape = drive->driver_data;
1750
1751 #if IDETAPE_DEBUG_LOG
1752         if (tape->debug_level >= 4)
1753                 printk(KERN_INFO "ide-tape: Reached idetape_request_sense_callback\n");
1754 #endif /* IDETAPE_DEBUG_LOG */
1755         if (!tape->pc->error) {
1756                 idetape_analyze_error(drive, (idetape_request_sense_result_t *) tape->pc->buffer);
1757                 idetape_end_request(drive, 1, 0);
1758         } else {
1759                 printk(KERN_ERR "ide-tape: Error in REQUEST SENSE itself - Aborting request!\n");
1760                 idetape_end_request(drive, 0, 0);
1761         }
1762         return ide_stopped;
1763 }
1764
1765 static void idetape_create_request_sense_cmd (idetape_pc_t *pc)
1766 {
1767         idetape_init_pc(pc);    
1768         pc->c[0] = IDETAPE_REQUEST_SENSE_CMD;
1769         pc->c[4] = 20;
1770         pc->request_transfer = 20;
1771         pc->callback = &idetape_request_sense_callback;
1772 }
1773
1774 static void idetape_init_rq(struct request *rq, u8 cmd)
1775 {
1776         memset(rq, 0, sizeof(*rq));
1777         rq->flags = REQ_SPECIAL;
1778         rq->cmd[0] = cmd;
1779 }
1780
1781 /*
1782  *      idetape_queue_pc_head generates a new packet command request in front
1783  *      of the request queue, before the current request, so that it will be
1784  *      processed immediately, on the next pass through the driver.
1785  *
1786  *      idetape_queue_pc_head is called from the request handling part of
1787  *      the driver (the "bottom" part). Safe storage for the request should
1788  *      be allocated with idetape_next_pc_storage and idetape_next_rq_storage
1789  *      before calling idetape_queue_pc_head.
1790  *
1791  *      Memory for those requests is pre-allocated at initialization time, and
1792  *      is limited to IDETAPE_PC_STACK requests. We assume that we have enough
1793  *      space for the maximum possible number of inter-dependent packet commands.
1794  *
1795  *      The higher level of the driver - The ioctl handler and the character
1796  *      device handling functions should queue request to the lower level part
1797  *      and wait for their completion using idetape_queue_pc_tail or
1798  *      idetape_queue_rw_tail.
1799  */
1800 static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq)
1801 {
1802         struct ide_tape_obj *tape = drive->driver_data;
1803
1804         idetape_init_rq(rq, REQ_IDETAPE_PC1);
1805         rq->buffer = (char *) pc;
1806         rq->rq_disk = tape->disk;
1807         (void) ide_do_drive_cmd(drive, rq, ide_preempt);
1808 }
1809
1810 /*
1811  *      idetape_retry_pc is called when an error was detected during the
1812  *      last packet command. We queue a request sense packet command in
1813  *      the head of the request list.
1814  */
1815 static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
1816 {
1817         idetape_tape_t *tape = drive->driver_data;
1818         idetape_pc_t *pc;
1819         struct request *rq;
1820         atapi_error_t error;
1821
1822         error.all = HWIF(drive)->INB(IDE_ERROR_REG);
1823         pc = idetape_next_pc_storage(drive);
1824         rq = idetape_next_rq_storage(drive);
1825         idetape_create_request_sense_cmd(pc);
1826         set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
1827         idetape_queue_pc_head(drive, pc, rq);
1828         return ide_stopped;
1829 }
1830
1831 /*
1832  *      idetape_postpone_request postpones the current request so that
1833  *      ide.c will be able to service requests from another device on
1834  *      the same hwgroup while we are polling for DSC.
1835  */
1836 static void idetape_postpone_request (ide_drive_t *drive)
1837 {
1838         idetape_tape_t *tape = drive->driver_data;
1839
1840 #if IDETAPE_DEBUG_LOG
1841         if (tape->debug_level >= 4)
1842                 printk(KERN_INFO "ide-tape: idetape_postpone_request\n");
1843 #endif
1844         tape->postponed_rq = HWGROUP(drive)->rq;
1845         ide_stall_queue(drive, tape->dsc_polling_frequency);
1846 }
1847
1848 /*
1849  *      idetape_pc_intr is the usual interrupt handler which will be called
1850  *      during a packet command. We will transfer some of the data (as
1851  *      requested by the drive) and will re-point interrupt handler to us.
1852  *      When data transfer is finished, we will act according to the
1853  *      algorithm described before idetape_issue_packet_command.
1854  *
1855  */
1856 static ide_startstop_t idetape_pc_intr (ide_drive_t *drive)
1857 {
1858         ide_hwif_t *hwif = drive->hwif;
1859         idetape_tape_t *tape = drive->driver_data;
1860         atapi_status_t status;
1861         atapi_bcount_t bcount;
1862         atapi_ireason_t ireason;
1863         idetape_pc_t *pc = tape->pc;
1864
1865         unsigned int temp;
1866 #if SIMULATE_ERRORS
1867         static int error_sim_count = 0;
1868 #endif
1869
1870 #if IDETAPE_DEBUG_LOG
1871         if (tape->debug_level >= 4)
1872                 printk(KERN_INFO "ide-tape: Reached idetape_pc_intr "
1873                                 "interrupt handler\n");
1874 #endif /* IDETAPE_DEBUG_LOG */  
1875
1876         /* Clear the interrupt */
1877         status.all = HWIF(drive)->INB(IDE_STATUS_REG);
1878
1879         if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
1880                 if (HWIF(drive)->ide_dma_end(drive) || status.b.check) {
1881                         /*
1882                          * A DMA error is sometimes expected. For example,
1883                          * if the tape is crossing a filemark during a
1884                          * READ command, it will issue an irq and position
1885                          * itself before the filemark, so that only a partial
1886                          * data transfer will occur (which causes the DMA
1887                          * error). In that case, we will later ask the tape
1888                          * how much bytes of the original request were
1889                          * actually transferred (we can't receive that
1890                          * information from the DMA engine on most chipsets).
1891                          */
1892
1893                         /*
1894                          * On the contrary, a DMA error is never expected;
1895                          * it usually indicates a hardware error or abort.
1896                          * If the tape crosses a filemark during a READ
1897                          * command, it will issue an irq and position itself
1898                          * after the filemark (not before). Only a partial
1899                          * data transfer will occur, but no DMA error.
1900                          * (AS, 19 Apr 2001)
1901                          */
1902                         set_bit(PC_DMA_ERROR, &pc->flags);
1903                 } else {
1904                         pc->actually_transferred = pc->request_transfer;
1905                         idetape_update_buffers(pc);
1906                 }
1907 #if IDETAPE_DEBUG_LOG
1908                 if (tape->debug_level >= 4)
1909                         printk(KERN_INFO "ide-tape: DMA finished\n");
1910 #endif /* IDETAPE_DEBUG_LOG */
1911         }
1912
1913         /* No more interrupts */
1914         if (!status.b.drq) {
1915 #if IDETAPE_DEBUG_LOG
1916                 if (tape->debug_level >= 2)
1917                         printk(KERN_INFO "ide-tape: Packet command completed, %d bytes transferred\n", pc->actually_transferred);
1918 #endif /* IDETAPE_DEBUG_LOG */
1919                 clear_bit(PC_DMA_IN_PROGRESS, &pc->flags);
1920
1921                 local_irq_enable();
1922
1923 #if SIMULATE_ERRORS
1924                 if ((pc->c[0] == IDETAPE_WRITE_CMD ||
1925                      pc->c[0] == IDETAPE_READ_CMD) &&
1926                     (++error_sim_count % 100) == 0) {
1927                         printk(KERN_INFO "ide-tape: %s: simulating error\n",
1928                                 tape->name);
1929                         status.b.check = 1;
1930                 }
1931 #endif
1932                 if (status.b.check && pc->c[0] == IDETAPE_REQUEST_SENSE_CMD)
1933                         status.b.check = 0;
1934                 if (status.b.check || test_bit(PC_DMA_ERROR, &pc->flags)) {     /* Error detected */
1935 #if IDETAPE_DEBUG_LOG
1936                         if (tape->debug_level >= 1)
1937                                 printk(KERN_INFO "ide-tape: %s: I/O error\n",
1938                                         tape->name);
1939 #endif /* IDETAPE_DEBUG_LOG */
1940                         if (pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
1941                                 printk(KERN_ERR "ide-tape: I/O error in request sense command\n");
1942                                 return ide_do_reset(drive);
1943                         }
1944 #if IDETAPE_DEBUG_LOG
1945                         if (tape->debug_level >= 1)
1946                                 printk(KERN_INFO "ide-tape: [cmd %x]: check condition\n", pc->c[0]);
1947 #endif
1948                         /* Retry operation */
1949                         return idetape_retry_pc(drive);
1950                 }
1951                 pc->error = 0;
1952                 if (test_bit(PC_WAIT_FOR_DSC, &pc->flags) &&
1953                     !status.b.dsc) {
1954                         /* Media access command */
1955                         tape->dsc_polling_start = jiffies;
1956                         tape->dsc_polling_frequency = IDETAPE_DSC_MA_FAST;
1957                         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
1958                         /* Allow ide.c to handle other requests */
1959                         idetape_postpone_request(drive);
1960                         return ide_stopped;
1961                 }
1962                 if (tape->failed_pc == pc)
1963                         tape->failed_pc = NULL;
1964                 /* Command finished - Call the callback function */
1965                 return pc->callback(drive);
1966         }
1967         if (test_and_clear_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
1968                 printk(KERN_ERR "ide-tape: The tape wants to issue more "
1969                                 "interrupts in DMA mode\n");
1970                 printk(KERN_ERR "ide-tape: DMA disabled, reverting to PIO\n");
1971                 (void)__ide_dma_off(drive);
1972                 return ide_do_reset(drive);
1973         }
1974         /* Get the number of bytes to transfer on this interrupt. */
1975         bcount.b.high = hwif->INB(IDE_BCOUNTH_REG);
1976         bcount.b.low = hwif->INB(IDE_BCOUNTL_REG);
1977
1978         ireason.all = hwif->INB(IDE_IREASON_REG);
1979
1980         if (ireason.b.cod) {
1981                 printk(KERN_ERR "ide-tape: CoD != 0 in idetape_pc_intr\n");
1982                 return ide_do_reset(drive);
1983         }
1984         if (ireason.b.io == test_bit(PC_WRITING, &pc->flags)) {
1985                 /* Hopefully, we will never get here */
1986                 printk(KERN_ERR "ide-tape: We wanted to %s, ",
1987                         ireason.b.io ? "Write":"Read");
1988                 printk(KERN_ERR "ide-tape: but the tape wants us to %s !\n",
1989                         ireason.b.io ? "Read":"Write");
1990                 return ide_do_reset(drive);
1991         }
1992         if (!test_bit(PC_WRITING, &pc->flags)) {
1993                 /* Reading - Check that we have enough space */
1994                 temp = pc->actually_transferred + bcount.all;
1995                 if (temp > pc->request_transfer) {
1996                         if (temp > pc->buffer_size) {
1997                                 printk(KERN_ERR "ide-tape: The tape wants to send us more data than expected - discarding data\n");
1998                                 idetape_discard_data(drive, bcount.all);
1999                                 ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2000                                 return ide_started;
2001                         }
2002 #if IDETAPE_DEBUG_LOG
2003                         if (tape->debug_level >= 2)
2004                                 printk(KERN_NOTICE "ide-tape: The tape wants to send us more data than expected - allowing transfer\n");
2005 #endif /* IDETAPE_DEBUG_LOG */
2006                 }
2007         }
2008         if (test_bit(PC_WRITING, &pc->flags)) {
2009                 if (pc->bh != NULL)
2010                         idetape_output_buffers(drive, pc, bcount.all);
2011                 else
2012                         /* Write the current buffer */
2013                         HWIF(drive)->atapi_output_bytes(drive, pc->current_position, bcount.all);
2014         } else {
2015                 if (pc->bh != NULL)
2016                         idetape_input_buffers(drive, pc, bcount.all);
2017                 else
2018                         /* Read the current buffer */
2019                         HWIF(drive)->atapi_input_bytes(drive, pc->current_position, bcount.all);
2020         }
2021         /* Update the current position */
2022         pc->actually_transferred += bcount.all;
2023         pc->current_position += bcount.all;
2024 #if IDETAPE_DEBUG_LOG
2025         if (tape->debug_level >= 2)
2026                 printk(KERN_INFO "ide-tape: [cmd %x] transferred %d bytes on that interrupt\n", pc->c[0], bcount.all);
2027 #endif
2028         /* And set the interrupt handler again */
2029         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2030         return ide_started;
2031 }
2032
2033 /*
2034  *      Packet Command Interface
2035  *
2036  *      The current Packet Command is available in tape->pc, and will not
2037  *      change until we finish handling it. Each packet command is associated
2038  *      with a callback function that will be called when the command is
2039  *      finished.
2040  *
2041  *      The handling will be done in three stages:
2042  *
2043  *      1.      idetape_issue_packet_command will send the packet command to the
2044  *              drive, and will set the interrupt handler to idetape_pc_intr.
2045  *
2046  *      2.      On each interrupt, idetape_pc_intr will be called. This step
2047  *              will be repeated until the device signals us that no more
2048  *              interrupts will be issued.
2049  *
2050  *      3.      ATAPI Tape media access commands have immediate status with a
2051  *              delayed process. In case of a successful initiation of a
2052  *              media access packet command, the DSC bit will be set when the
2053  *              actual execution of the command is finished. 
2054  *              Since the tape drive will not issue an interrupt, we have to
2055  *              poll for this event. In this case, we define the request as
2056  *              "low priority request" by setting rq_status to
2057  *              IDETAPE_RQ_POSTPONED,   set a timer to poll for DSC and exit
2058  *              the driver.
2059  *
2060  *              ide.c will then give higher priority to requests which
2061  *              originate from the other device, until will change rq_status
2062  *              to RQ_ACTIVE.
2063  *
2064  *      4.      When the packet command is finished, it will be checked for errors.
2065  *
2066  *      5.      In case an error was found, we queue a request sense packet
2067  *              command in front of the request queue and retry the operation
2068  *              up to IDETAPE_MAX_PC_RETRIES times.
2069  *
2070  *      6.      In case no error was found, or we decided to give up and not
2071  *              to retry again, the callback function will be called and then
2072  *              we will handle the next request.
2073  *
2074  */
2075 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
2076 {
2077         ide_hwif_t *hwif = drive->hwif;
2078         idetape_tape_t *tape = drive->driver_data;
2079         idetape_pc_t *pc = tape->pc;
2080         atapi_ireason_t ireason;
2081         int retries = 100;
2082         ide_startstop_t startstop;
2083
2084         if (ide_wait_stat(&startstop,drive,DRQ_STAT,BUSY_STAT,WAIT_READY)) {
2085                 printk(KERN_ERR "ide-tape: Strange, packet command initiated yet DRQ isn't asserted\n");
2086                 return startstop;
2087         }
2088         ireason.all = hwif->INB(IDE_IREASON_REG);
2089         while (retries-- && (!ireason.b.cod || ireason.b.io)) {
2090                 printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while issuing "
2091                                 "a packet command, retrying\n");
2092                 udelay(100);
2093                 ireason.all = hwif->INB(IDE_IREASON_REG);
2094                 if (retries == 0) {
2095                         printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while "
2096                                         "issuing a packet command, ignoring\n");
2097                         ireason.b.cod = 1;
2098                         ireason.b.io = 0;
2099                 }
2100         }
2101         if (!ireason.b.cod || ireason.b.io) {
2102                 printk(KERN_ERR "ide-tape: (IO,CoD) != (0,1) while issuing "
2103                                 "a packet command\n");
2104                 return ide_do_reset(drive);
2105         }
2106         /* Set the interrupt routine */
2107         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2108 #ifdef CONFIG_BLK_DEV_IDEDMA
2109         /* Begin DMA, if necessary */
2110         if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags))
2111                 hwif->dma_start(drive);
2112 #endif
2113         /* Send the actual packet */
2114         HWIF(drive)->atapi_output_bytes(drive, pc->c, 12);
2115         return ide_started;
2116 }
2117
2118 static ide_startstop_t idetape_issue_packet_command (ide_drive_t *drive, idetape_pc_t *pc)
2119 {
2120         ide_hwif_t *hwif = drive->hwif;
2121         idetape_tape_t *tape = drive->driver_data;
2122         atapi_bcount_t bcount;
2123         int dma_ok = 0;
2124
2125 #if IDETAPE_DEBUG_BUGS
2126         if (tape->pc->c[0] == IDETAPE_REQUEST_SENSE_CMD &&
2127             pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
2128                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
2129                         "Two request sense in serial were issued\n");
2130         }
2131 #endif /* IDETAPE_DEBUG_BUGS */
2132
2133         if (tape->failed_pc == NULL && pc->c[0] != IDETAPE_REQUEST_SENSE_CMD)
2134                 tape->failed_pc = pc;
2135         /* Set the current packet command */
2136         tape->pc = pc;
2137
2138         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
2139             test_bit(PC_ABORT, &pc->flags)) {
2140                 /*
2141                  *      We will "abort" retrying a packet command in case
2142                  *      a legitimate error code was received (crossing a
2143                  *      filemark, or end of the media, for example).
2144                  */
2145                 if (!test_bit(PC_ABORT, &pc->flags)) {
2146                         if (!(pc->c[0] == IDETAPE_TEST_UNIT_READY_CMD &&
2147                               tape->sense_key == 2 && tape->asc == 4 &&
2148                              (tape->ascq == 1 || tape->ascq == 8))) {
2149                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
2150                                                 "pc = %2x, key = %2x, "
2151                                                 "asc = %2x, ascq = %2x\n",
2152                                                 tape->name, pc->c[0],
2153                                                 tape->sense_key, tape->asc,
2154                                                 tape->ascq);
2155                         }
2156                         /* Giving up */
2157                         pc->error = IDETAPE_ERROR_GENERAL;
2158                 }
2159                 tape->failed_pc = NULL;
2160                 return pc->callback(drive);
2161         }
2162 #if IDETAPE_DEBUG_LOG
2163         if (tape->debug_level >= 2)
2164                 printk(KERN_INFO "ide-tape: Retry number - %d, cmd = %02X\n", pc->retries, pc->c[0]);
2165 #endif /* IDETAPE_DEBUG_LOG */
2166
2167         pc->retries++;
2168         /* We haven't transferred any data yet */
2169         pc->actually_transferred = 0;
2170         pc->current_position = pc->buffer;
2171         /* Request to transfer the entire buffer at once */
2172         bcount.all = pc->request_transfer;
2173
2174         if (test_and_clear_bit(PC_DMA_ERROR, &pc->flags)) {
2175                 printk(KERN_WARNING "ide-tape: DMA disabled, "
2176                                 "reverting to PIO\n");
2177                 (void)__ide_dma_off(drive);
2178         }
2179         if (test_bit(PC_DMA_RECOMMENDED, &pc->flags) && drive->using_dma)
2180                 dma_ok = !hwif->dma_setup(drive);
2181
2182         if (IDE_CONTROL_REG)
2183                 hwif->OUTB(drive->ctl, IDE_CONTROL_REG);
2184         hwif->OUTB(dma_ok ? 1 : 0, IDE_FEATURE_REG);    /* Use PIO/DMA */
2185         hwif->OUTB(bcount.b.high, IDE_BCOUNTH_REG);
2186         hwif->OUTB(bcount.b.low, IDE_BCOUNTL_REG);
2187         hwif->OUTB(drive->select.all, IDE_SELECT_REG);
2188         if (dma_ok)                     /* Will begin DMA later */
2189                 set_bit(PC_DMA_IN_PROGRESS, &pc->flags);
2190         if (test_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags)) {
2191                 ide_set_handler(drive, &idetape_transfer_pc, IDETAPE_WAIT_CMD, NULL);
2192                 hwif->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
2193                 return ide_started;
2194         } else {
2195                 hwif->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
2196                 return idetape_transfer_pc(drive);
2197         }
2198 }
2199
2200 /*
2201  *      General packet command callback function.
2202  */
2203 static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
2204 {
2205         idetape_tape_t *tape = drive->driver_data;
2206         
2207 #if IDETAPE_DEBUG_LOG
2208         if (tape->debug_level >= 4)
2209                 printk(KERN_INFO "ide-tape: Reached idetape_pc_callback\n");
2210 #endif /* IDETAPE_DEBUG_LOG */
2211
2212         idetape_end_request(drive, tape->pc->error ? 0 : 1, 0);
2213         return ide_stopped;
2214 }
2215
2216 /*
2217  *      A mode sense command is used to "sense" tape parameters.
2218  */
2219 static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
2220 {
2221         idetape_init_pc(pc);
2222         pc->c[0] = IDETAPE_MODE_SENSE_CMD;
2223         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
2224                 pc->c[1] = 8;   /* DBD = 1 - Don't return block descriptors */
2225         pc->c[2] = page_code;
2226         /*
2227          * Changed pc->c[3] to 0 (255 will at best return unused info).
2228          *
2229          * For SCSI this byte is defined as subpage instead of high byte
2230          * of length and some IDE drives seem to interpret it this way
2231          * and return an error when 255 is used.
2232          */
2233         pc->c[3] = 0;
2234         pc->c[4] = 255;         /* (We will just discard data in that case) */
2235         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
2236                 pc->request_transfer = 12;
2237         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
2238                 pc->request_transfer = 24;
2239         else
2240                 pc->request_transfer = 50;
2241         pc->callback = &idetape_pc_callback;
2242 }
2243
2244 static void calculate_speeds(ide_drive_t *drive)
2245 {
2246         idetape_tape_t *tape = drive->driver_data;
2247         int full = 125, empty = 75;
2248
2249         if (time_after(jiffies, tape->controlled_pipeline_head_time + 120 * HZ)) {
2250                 tape->controlled_previous_pipeline_head = tape->controlled_last_pipeline_head;
2251                 tape->controlled_previous_head_time = tape->controlled_pipeline_head_time;
2252                 tape->controlled_last_pipeline_head = tape->pipeline_head;
2253                 tape->controlled_pipeline_head_time = jiffies;
2254         }
2255         if (time_after(jiffies, tape->controlled_pipeline_head_time + 60 * HZ))
2256                 tape->controlled_pipeline_head_speed = (tape->pipeline_head - tape->controlled_last_pipeline_head) * 32 * HZ / (jiffies - tape->controlled_pipeline_head_time);
2257         else if (time_after(jiffies, tape->controlled_previous_head_time))
2258                 tape->controlled_pipeline_head_speed = (tape->pipeline_head - tape->controlled_previous_pipeline_head) * 32 * HZ / (jiffies - tape->controlled_previous_head_time);
2259
2260         if (tape->nr_pending_stages < tape->max_stages /*- 1 */) {
2261                 /* -1 for read mode error recovery */
2262                 if (time_after(jiffies, tape->uncontrolled_previous_head_time + 10 * HZ)) {
2263                         tape->uncontrolled_pipeline_head_time = jiffies;
2264                         tape->uncontrolled_pipeline_head_speed = (tape->pipeline_head - tape->uncontrolled_previous_pipeline_head) * 32 * HZ / (jiffies - tape->uncontrolled_previous_head_time);
2265                 }
2266         } else {
2267                 tape->uncontrolled_previous_head_time = jiffies;
2268                 tape->uncontrolled_previous_pipeline_head = tape->pipeline_head;
2269                 if (time_after(jiffies, tape->uncontrolled_pipeline_head_time + 30 * HZ)) {
2270                         tape->uncontrolled_pipeline_head_time = jiffies;
2271                 }
2272         }
2273         tape->pipeline_head_speed = max(tape->uncontrolled_pipeline_head_speed, tape->controlled_pipeline_head_speed);
2274         if (tape->speed_control == 0) {
2275                 tape->max_insert_speed = 5000;
2276         } else if (tape->speed_control == 1) {
2277                 if (tape->nr_pending_stages >= tape->max_stages / 2)
2278                         tape->max_insert_speed = tape->pipeline_head_speed +
2279                                 (1100 - tape->pipeline_head_speed) * 2 * (tape->nr_pending_stages - tape->max_stages / 2) / tape->max_stages;
2280                 else
2281                         tape->max_insert_speed = 500 +
2282                                 (tape->pipeline_head_speed - 500) * 2 * tape->nr_pending_stages / tape->max_stages;
2283                 if (tape->nr_pending_stages >= tape->max_stages * 99 / 100)
2284                         tape->max_insert_speed = 5000;
2285         } else if (tape->speed_control == 2) {
2286                 tape->max_insert_speed = tape->pipeline_head_speed * empty / 100 +
2287                         (tape->pipeline_head_speed * full / 100 - tape->pipeline_head_speed * empty / 100) * tape->nr_pending_stages / tape->max_stages;
2288         } else
2289                 tape->max_insert_speed = tape->speed_control;
2290         tape->max_insert_speed = max(tape->max_insert_speed, 500);
2291 }
2292
2293 static ide_startstop_t idetape_media_access_finished (ide_drive_t *drive)
2294 {
2295         idetape_tape_t *tape = drive->driver_data;
2296         idetape_pc_t *pc = tape->pc;
2297         atapi_status_t status;
2298
2299         status.all = HWIF(drive)->INB(IDE_STATUS_REG);
2300         if (status.b.dsc) {
2301                 if (status.b.check) {
2302                         /* Error detected */
2303                         if (pc->c[0] != IDETAPE_TEST_UNIT_READY_CMD)
2304                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
2305                                                 tape->name);
2306                         /* Retry operation */
2307                         return idetape_retry_pc(drive);
2308                 }
2309                 pc->error = 0;
2310                 if (tape->failed_pc == pc)
2311                         tape->failed_pc = NULL;
2312         } else {
2313                 pc->error = IDETAPE_ERROR_GENERAL;
2314                 tape->failed_pc = NULL;
2315         }
2316         return pc->callback(drive);
2317 }
2318
2319 static ide_startstop_t idetape_rw_callback (ide_drive_t *drive)
2320 {
2321         idetape_tape_t *tape = drive->driver_data;
2322         struct request *rq = HWGROUP(drive)->rq;
2323         int blocks = tape->pc->actually_transferred / tape->tape_block_size;
2324
2325         tape->avg_size += blocks * tape->tape_block_size;
2326         tape->insert_size += blocks * tape->tape_block_size;
2327         if (tape->insert_size > 1024 * 1024)
2328                 tape->measure_insert_time = 1;
2329         if (tape->measure_insert_time) {
2330                 tape->measure_insert_time = 0;
2331                 tape->insert_time = jiffies;
2332                 tape->insert_size = 0;
2333         }
2334         if (time_after(jiffies, tape->insert_time))
2335                 tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
2336         if (jiffies - tape->avg_time >= HZ) {
2337                 tape->avg_speed = tape->avg_size * HZ / (jiffies - tape->avg_time) / 1024;
2338                 tape->avg_size = 0;
2339                 tape->avg_time = jiffies;
2340         }
2341
2342 #if IDETAPE_DEBUG_LOG   
2343         if (tape->debug_level >= 4)
2344                 printk(KERN_INFO "ide-tape: Reached idetape_rw_callback\n");
2345 #endif /* IDETAPE_DEBUG_LOG */
2346
2347         tape->first_frame_position += blocks;
2348         rq->current_nr_sectors -= blocks;
2349
2350         if (!tape->pc->error)
2351                 idetape_end_request(drive, 1, 0);
2352         else
2353                 idetape_end_request(drive, tape->pc->error, 0);
2354         return ide_stopped;
2355 }
2356
2357 static void idetape_create_read_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2358 {
2359         idetape_init_pc(pc);
2360         pc->c[0] = IDETAPE_READ_CMD;
2361         put_unaligned(htonl(length), (unsigned int *) &pc->c[1]);
2362         pc->c[1] = 1;
2363         pc->callback = &idetape_rw_callback;
2364         pc->bh = bh;
2365         atomic_set(&bh->b_count, 0);
2366         pc->buffer = NULL;
2367         pc->request_transfer = pc->buffer_size = length * tape->tape_block_size;
2368         if (pc->request_transfer == tape->stage_size)
2369                 set_bit(PC_DMA_RECOMMENDED, &pc->flags);
2370 }
2371
2372 static void idetape_create_read_buffer_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2373 {
2374         int size = 32768;
2375         struct idetape_bh *p = bh;
2376
2377         idetape_init_pc(pc);
2378         pc->c[0] = IDETAPE_READ_BUFFER_CMD;
2379         pc->c[1] = IDETAPE_RETRIEVE_FAULTY_BLOCK;
2380         pc->c[7] = size >> 8;
2381         pc->c[8] = size & 0xff;
2382         pc->callback = &idetape_pc_callback;
2383         pc->bh = bh;
2384         atomic_set(&bh->b_count, 0);
2385         pc->buffer = NULL;
2386         while (p) {
2387                 atomic_set(&p->b_count, 0);
2388                 p = p->b_reqnext;
2389         }
2390         pc->request_transfer = pc->buffer_size = size;
2391 }
2392
2393 static void idetape_create_write_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2394 {
2395         idetape_init_pc(pc);
2396         pc->c[0] = IDETAPE_WRITE_CMD;
2397         put_unaligned(htonl(length), (unsigned int *) &pc->c[1]);
2398         pc->c[1] = 1;
2399         pc->callback = &idetape_rw_callback;
2400         set_bit(PC_WRITING, &pc->flags);
2401         pc->bh = bh;
2402         pc->b_data = bh->b_data;
2403         pc->b_count = atomic_read(&bh->b_count);
2404         pc->buffer = NULL;
2405         pc->request_transfer = pc->buffer_size = length * tape->tape_block_size;
2406         if (pc->request_transfer == tape->stage_size)
2407                 set_bit(PC_DMA_RECOMMENDED, &pc->flags);
2408 }
2409
2410 /*
2411  * idetape_do_request is our request handling function. 
2412  */
2413 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
2414                                           struct request *rq, sector_t block)
2415 {
2416         idetape_tape_t *tape = drive->driver_data;
2417         idetape_pc_t *pc = NULL;
2418         struct request *postponed_rq = tape->postponed_rq;
2419         atapi_status_t status;
2420
2421 #if IDETAPE_DEBUG_LOG
2422 #if 0
2423         if (tape->debug_level >= 5)
2424                 printk(KERN_INFO "ide-tape: rq_status: %d, "
2425                         "dev: %s, cmd: %ld, errors: %d\n", rq->rq_status,
2426                          rq->rq_disk->disk_name, rq->cmd[0], rq->errors);
2427 #endif
2428         if (tape->debug_level >= 2)
2429                 printk(KERN_INFO "ide-tape: sector: %ld, "
2430                         "nr_sectors: %ld, current_nr_sectors: %d\n",
2431                         rq->sector, rq->nr_sectors, rq->current_nr_sectors);
2432 #endif /* IDETAPE_DEBUG_LOG */
2433
2434         if ((rq->flags & REQ_SPECIAL) == 0) {
2435                 /*
2436                  * We do not support buffer cache originated requests.
2437                  */
2438                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
2439                         "request queue (%ld)\n", drive->name, rq->flags);
2440                 ide_end_request(drive, 0, 0);
2441                 return ide_stopped;
2442         }
2443
2444         /*
2445          *      Retry a failed packet command
2446          */
2447         if (tape->failed_pc != NULL &&
2448             tape->pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
2449                 return idetape_issue_packet_command(drive, tape->failed_pc);
2450         }
2451 #if IDETAPE_DEBUG_BUGS
2452         if (postponed_rq != NULL)
2453                 if (rq != postponed_rq) {
2454                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
2455                                         "Two DSC requests were queued\n");
2456                         idetape_end_request(drive, 0, 0);
2457                         return ide_stopped;
2458                 }
2459 #endif /* IDETAPE_DEBUG_BUGS */
2460
2461         tape->postponed_rq = NULL;
2462
2463         /*
2464          * If the tape is still busy, postpone our request and service
2465          * the other device meanwhile.
2466          */
2467         status.all = HWIF(drive)->INB(IDE_STATUS_REG);
2468
2469         if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
2470                 set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
2471
2472         if (drive->post_reset == 1) {
2473                 set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
2474                 drive->post_reset = 0;
2475         }
2476
2477         if (tape->tape_still_time > 100 && tape->tape_still_time < 200)
2478                 tape->measure_insert_time = 1;
2479         if (time_after(jiffies, tape->insert_time))
2480                 tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
2481         calculate_speeds(drive);
2482         if (!test_and_clear_bit(IDETAPE_IGNORE_DSC, &tape->flags) &&
2483             !status.b.dsc) {
2484                 if (postponed_rq == NULL) {
2485                         tape->dsc_polling_start = jiffies;
2486                         tape->dsc_polling_frequency = tape->best_dsc_rw_frequency;
2487                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
2488                 } else if (time_after(jiffies, tape->dsc_timeout)) {
2489                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
2490                                 tape->name);
2491                         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
2492                                 idetape_media_access_finished(drive);
2493                                 return ide_stopped;
2494                         } else {
2495                                 return ide_do_reset(drive);
2496                         }
2497                 } else if (jiffies - tape->dsc_polling_start > IDETAPE_DSC_MA_THRESHOLD)
2498                         tape->dsc_polling_frequency = IDETAPE_DSC_MA_SLOW;
2499                 idetape_postpone_request(drive);
2500                 return ide_stopped;
2501         }
2502         if (rq->cmd[0] & REQ_IDETAPE_READ) {
2503                 tape->buffer_head++;
2504 #if USE_IOTRACE
2505                 IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
2506 #endif
2507                 tape->postpone_cnt = 0;
2508                 pc = idetape_next_pc_storage(drive);
2509                 idetape_create_read_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2510                 goto out;
2511         }
2512         if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
2513                 tape->buffer_head++;
2514 #if USE_IOTRACE
2515                 IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
2516 #endif
2517                 tape->postpone_cnt = 0;
2518                 pc = idetape_next_pc_storage(drive);
2519                 idetape_create_write_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2520                 goto out;
2521         }
2522         if (rq->cmd[0] & REQ_IDETAPE_READ_BUFFER) {
2523                 tape->postpone_cnt = 0;
2524                 pc = idetape_next_pc_storage(drive);
2525                 idetape_create_read_buffer_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2526                 goto out;
2527         }
2528         if (rq->cmd[0] & REQ_IDETAPE_PC1) {
2529                 pc = (idetape_pc_t *) rq->buffer;
2530                 rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
2531                 rq->cmd[0] |= REQ_IDETAPE_PC2;
2532                 goto out;
2533         }
2534         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
2535                 idetape_media_access_finished(drive);
2536                 return ide_stopped;
2537         }
2538         BUG();
2539 out:
2540         return idetape_issue_packet_command(drive, pc);
2541 }
2542
2543 /*
2544  *      Pipeline related functions
2545  */
2546 static inline int idetape_pipeline_active (idetape_tape_t *tape)
2547 {
2548         int rc1, rc2;
2549
2550         rc1 = test_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
2551         rc2 = (tape->active_data_request != NULL);
2552         return rc1;
2553 }
2554
2555 /*
2556  *      idetape_kmalloc_stage uses __get_free_page to allocate a pipeline
2557  *      stage, along with all the necessary small buffers which together make
2558  *      a buffer of size tape->stage_size (or a bit more). We attempt to
2559  *      combine sequential pages as much as possible.
2560  *
2561  *      Returns a pointer to the new allocated stage, or NULL if we
2562  *      can't (or don't want to) allocate a stage.
2563  *
2564  *      Pipeline stages are optional and are used to increase performance.
2565  *      If we can't allocate them, we'll manage without them.
2566  */
2567 static idetape_stage_t *__idetape_kmalloc_stage (idetape_tape_t *tape, int full, int clear)
2568 {
2569         idetape_stage_t *stage;
2570         struct idetape_bh *prev_bh, *bh;
2571         int pages = tape->pages_per_stage;
2572         char *b_data = NULL;
2573
2574         if ((stage = (idetape_stage_t *) kmalloc (sizeof (idetape_stage_t),GFP_KERNEL)) == NULL)
2575                 return NULL;
2576         stage->next = NULL;
2577
2578         bh = stage->bh = (struct idetape_bh *)kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
2579         if (bh == NULL)
2580                 goto abort;
2581         bh->b_reqnext = NULL;
2582         if ((bh->b_data = (char *) __get_free_page (GFP_KERNEL)) == NULL)
2583                 goto abort;
2584         if (clear)
2585                 memset(bh->b_data, 0, PAGE_SIZE);
2586         bh->b_size = PAGE_SIZE;
2587         atomic_set(&bh->b_count, full ? bh->b_size : 0);
2588
2589         while (--pages) {
2590                 if ((b_data = (char *) __get_free_page (GFP_KERNEL)) == NULL)
2591                         goto abort;
2592                 if (clear)
2593                         memset(b_data, 0, PAGE_SIZE);
2594                 if (bh->b_data == b_data + PAGE_SIZE) {
2595                         bh->b_size += PAGE_SIZE;
2596                         bh->b_data -= PAGE_SIZE;
2597                         if (full)
2598                                 atomic_add(PAGE_SIZE, &bh->b_count);
2599                         continue;
2600                 }
2601                 if (b_data == bh->b_data + bh->b_size) {
2602                         bh->b_size += PAGE_SIZE;
2603                         if (full)
2604                                 atomic_add(PAGE_SIZE, &bh->b_count);
2605                         continue;
2606                 }
2607                 prev_bh = bh;
2608                 if ((bh = (struct idetape_bh *)kmalloc(sizeof(struct idetape_bh), GFP_KERNEL)) == NULL) {
2609                         free_page((unsigned long) b_data);
2610                         goto abort;
2611                 }
2612                 bh->b_reqnext = NULL;
2613                 bh->b_data = b_data;
2614                 bh->b_size = PAGE_SIZE;
2615                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
2616                 prev_bh->b_reqnext = bh;
2617         }
2618         bh->b_size -= tape->excess_bh_size;
2619         if (full)
2620                 atomic_sub(tape->excess_bh_size, &bh->b_count);
2621         return stage;
2622 abort:
2623         __idetape_kfree_stage(stage);
2624         return NULL;
2625 }
2626
2627 static idetape_stage_t *idetape_kmalloc_stage (idetape_tape_t *tape)
2628 {
2629         idetape_stage_t *cache_stage = tape->cache_stage;
2630
2631 #if IDETAPE_DEBUG_LOG
2632         if (tape->debug_level >= 4)
2633                 printk(KERN_INFO "ide-tape: Reached idetape_kmalloc_stage\n");
2634 #endif /* IDETAPE_DEBUG_LOG */
2635
2636         if (tape->nr_stages >= tape->max_stages)
2637                 return NULL;
2638         if (cache_stage != NULL) {
2639                 tape->cache_stage = NULL;
2640                 return cache_stage;
2641         }
2642         return __idetape_kmalloc_stage(tape, 0, 0);
2643 }
2644
2645 static void idetape_copy_stage_from_user (idetape_tape_t *tape, idetape_stage_t *stage, const char __user *buf, int n)
2646 {
2647         struct idetape_bh *bh = tape->bh;
2648         int count;
2649
2650         while (n) {
2651 #if IDETAPE_DEBUG_BUGS
2652                 if (bh == NULL) {
2653                         printk(KERN_ERR "ide-tape: bh == NULL in "
2654                                 "idetape_copy_stage_from_user\n");
2655                         return;
2656                 }
2657 #endif /* IDETAPE_DEBUG_BUGS */
2658                 count = min((unsigned int)(bh->b_size - atomic_read(&bh->b_count)), (unsigned int)n);
2659                 copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf, count);
2660                 n -= count;
2661                 atomic_add(count, &bh->b_count);
2662                 buf += count;
2663                 if (atomic_read(&bh->b_count) == bh->b_size) {
2664                         bh = bh->b_reqnext;
2665                         if (bh)
2666                                 atomic_set(&bh->b_count, 0);
2667                 }
2668         }
2669         tape->bh = bh;
2670 }
2671
2672 static void idetape_copy_stage_to_user (idetape_tape_t *tape, char __user *buf, idetape_stage_t *stage, int n)
2673 {
2674         struct idetape_bh *bh = tape->bh;
2675         int count;
2676
2677         while (n) {
2678 #if IDETAPE_DEBUG_BUGS
2679                 if (bh == NULL) {
2680                         printk(KERN_ERR "ide-tape: bh == NULL in "
2681                                 "idetape_copy_stage_to_user\n");
2682                         return;
2683                 }
2684 #endif /* IDETAPE_DEBUG_BUGS */
2685                 count = min(tape->b_count, n);
2686                 copy_to_user(buf, tape->b_data, count);
2687                 n -= count;
2688                 tape->b_data += count;
2689                 tape->b_count -= count;
2690                 buf += count;
2691                 if (!tape->b_count) {
2692                         tape->bh = bh = bh->b_reqnext;
2693                         if (bh) {
2694                                 tape->b_data = bh->b_data;
2695                                 tape->b_count = atomic_read(&bh->b_count);
2696                         }
2697                 }
2698         }
2699 }
2700
2701 static void idetape_init_merge_stage (idetape_tape_t *tape)
2702 {
2703         struct idetape_bh *bh = tape->merge_stage->bh;
2704         
2705         tape->bh = bh;
2706         if (tape->chrdev_direction == idetape_direction_write)
2707                 atomic_set(&bh->b_count, 0);
2708         else {
2709                 tape->b_data = bh->b_data;
2710                 tape->b_count = atomic_read(&bh->b_count);
2711         }
2712 }
2713
2714 static void idetape_switch_buffers (idetape_tape_t *tape, idetape_stage_t *stage)
2715 {
2716         struct idetape_bh *tmp;
2717
2718         tmp = stage->bh;
2719         stage->bh = tape->merge_stage->bh;
2720         tape->merge_stage->bh = tmp;
2721         idetape_init_merge_stage(tape);
2722 }
2723
2724 /*
2725  *      idetape_add_stage_tail adds a new stage at the end of the pipeline.
2726  */
2727 static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
2728 {
2729         idetape_tape_t *tape = drive->driver_data;
2730         unsigned long flags;
2731         
2732 #if IDETAPE_DEBUG_LOG
2733         if (tape->debug_level >= 4)
2734                 printk (KERN_INFO "ide-tape: Reached idetape_add_stage_tail\n");
2735 #endif /* IDETAPE_DEBUG_LOG */
2736         spin_lock_irqsave(&tape->spinlock, flags);
2737         stage->next = NULL;
2738         if (tape->last_stage != NULL)
2739                 tape->last_stage->next=stage;
2740         else
2741                 tape->first_stage = tape->next_stage=stage;
2742         tape->last_stage = stage;
2743         if (tape->next_stage == NULL)
2744                 tape->next_stage = tape->last_stage;
2745         tape->nr_stages++;
2746         tape->nr_pending_stages++;
2747         spin_unlock_irqrestore(&tape->spinlock, flags);
2748 }
2749
2750 /*
2751  *      idetape_wait_for_request installs a completion in a pending request
2752  *      and sleeps until it is serviced.
2753  *
2754  *      The caller should ensure that the request will not be serviced
2755  *      before we install the completion (usually by disabling interrupts).
2756  */
2757 static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq)
2758 {
2759         DECLARE_COMPLETION(wait);
2760         idetape_tape_t *tape = drive->driver_data;
2761
2762 #if IDETAPE_DEBUG_BUGS
2763         if (rq == NULL || (rq->flags & REQ_SPECIAL) == 0) {
2764                 printk (KERN_ERR "ide-tape: bug: Trying to sleep on non-valid request\n");
2765                 return;
2766         }
2767 #endif /* IDETAPE_DEBUG_BUGS */
2768         rq->waiting = &wait;
2769         rq->end_io = blk_end_sync_rq;
2770         spin_unlock_irq(&tape->spinlock);
2771         wait_for_completion(&wait);
2772         /* The stage and its struct request have been deallocated */
2773         spin_lock_irq(&tape->spinlock);
2774 }
2775
2776 static ide_startstop_t idetape_read_position_callback (ide_drive_t *drive)
2777 {
2778         idetape_tape_t *tape = drive->driver_data;
2779         idetape_read_position_result_t *result;
2780         
2781 #if IDETAPE_DEBUG_LOG
2782         if (tape->debug_level >= 4)
2783                 printk(KERN_INFO "ide-tape: Reached idetape_read_position_callback\n");
2784 #endif /* IDETAPE_DEBUG_LOG */
2785
2786         if (!tape->pc->error) {
2787                 result = (idetape_read_position_result_t *) tape->pc->buffer;
2788 #if IDETAPE_DEBUG_LOG
2789                 if (tape->debug_level >= 2)
2790                         printk(KERN_INFO "ide-tape: BOP - %s\n",result->bop ? "Yes":"No");
2791                 if (tape->debug_level >= 2)
2792                         printk(KERN_INFO "ide-tape: EOP - %s\n",result->eop ? "Yes":"No");
2793 #endif /* IDETAPE_DEBUG_LOG */
2794                 if (result->bpu) {
2795                         printk(KERN_INFO "ide-tape: Block location is unknown to the tape\n");
2796                         clear_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
2797                         idetape_end_request(drive, 0, 0);
2798                 } else {
2799 #if IDETAPE_DEBUG_LOG
2800                         if (tape->debug_level >= 2)
2801                                 printk(KERN_INFO "ide-tape: Block Location - %u\n", ntohl(result->first_block));
2802 #endif /* IDETAPE_DEBUG_LOG */
2803                         tape->partition = result->partition;
2804                         tape->first_frame_position = ntohl(result->first_block);
2805                         tape->last_frame_position = ntohl(result->last_block);
2806                         tape->blocks_in_buffer = result->blocks_in_buffer[2];
2807                         set_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
2808                         idetape_end_request(drive, 1, 0);
2809                 }
2810         } else {
2811                 idetape_end_request(drive, 0, 0);
2812         }
2813         return ide_stopped;
2814 }
2815
2816 /*
2817  *      idetape_create_write_filemark_cmd will:
2818  *
2819  *              1.      Write a filemark if write_filemark=1.
2820  *              2.      Flush the device buffers without writing a filemark
2821  *                      if write_filemark=0.
2822  *
2823  */
2824 static void idetape_create_write_filemark_cmd (ide_drive_t *drive, idetape_pc_t *pc,int write_filemark)
2825 {
2826         idetape_init_pc(pc);
2827         pc->c[0] = IDETAPE_WRITE_FILEMARK_CMD;
2828         pc->c[4] = write_filemark;
2829         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2830         pc->callback = &idetape_pc_callback;
2831 }
2832
2833 static void idetape_create_test_unit_ready_cmd(idetape_pc_t *pc)
2834 {
2835         idetape_init_pc(pc);
2836         pc->c[0] = IDETAPE_TEST_UNIT_READY_CMD;
2837         pc->callback = &idetape_pc_callback;
2838 }
2839
2840 /*
2841  *      idetape_queue_pc_tail is based on the following functions:
2842  *
2843  *      ide_do_drive_cmd from ide.c
2844  *      cdrom_queue_request and cdrom_queue_packet_command from ide-cd.c
2845  *
2846  *      We add a special packet command request to the tail of the request
2847  *      queue, and wait for it to be serviced.
2848  *
2849  *      This is not to be called from within the request handling part
2850  *      of the driver ! We allocate here data in the stack, and it is valid
2851  *      until the request is finished. This is not the case for the bottom
2852  *      part of the driver, where we are always leaving the functions to wait
2853  *      for an interrupt or a timer event.
2854  *
2855  *      From the bottom part of the driver, we should allocate safe memory
2856  *      using idetape_next_pc_storage and idetape_next_rq_storage, and add
2857  *      the request to the request list without waiting for it to be serviced !
2858  *      In that case, we usually use idetape_queue_pc_head.
2859  */
2860 static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc)
2861 {
2862         struct ide_tape_obj *tape = drive->driver_data;
2863         struct request rq;
2864
2865         idetape_init_rq(&rq, REQ_IDETAPE_PC1);
2866         rq.buffer = (char *) pc;
2867         rq.rq_disk = tape->disk;
2868         return ide_do_drive_cmd(drive, &rq, ide_wait);
2869 }
2870
2871 static void idetape_create_load_unload_cmd (ide_drive_t *drive, idetape_pc_t *pc,int cmd)
2872 {
2873         idetape_init_pc(pc);
2874         pc->c[0] = IDETAPE_LOAD_UNLOAD_CMD;
2875         pc->c[4] = cmd;
2876         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2877         pc->callback = &idetape_pc_callback;
2878 }
2879
2880 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
2881 {
2882         idetape_tape_t *tape = drive->driver_data;
2883         idetape_pc_t pc;
2884         int load_attempted = 0;
2885
2886         /*
2887          * Wait for the tape to become ready
2888          */
2889         set_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
2890         timeout += jiffies;
2891         while (time_before(jiffies, timeout)) {
2892                 idetape_create_test_unit_ready_cmd(&pc);
2893                 if (!__idetape_queue_pc_tail(drive, &pc))
2894                         return 0;
2895                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
2896                     || (tape->asc == 0x3A)) {   /* no media */
2897                         if (load_attempted)
2898                                 return -ENOMEDIUM;
2899                         idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
2900                         __idetape_queue_pc_tail(drive, &pc);
2901                         load_attempted = 1;
2902                 /* not about to be ready */
2903                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
2904                              (tape->ascq == 1 || tape->ascq == 8)))
2905                         return -EIO;
2906                 current->state = TASK_INTERRUPTIBLE;
2907                 schedule_timeout(HZ / 10);
2908         }
2909         return -EIO;
2910 }
2911
2912 static int idetape_queue_pc_tail (ide_drive_t *drive,idetape_pc_t *pc)
2913 {
2914         return __idetape_queue_pc_tail(drive, pc);
2915 }
2916
2917 static int idetape_flush_tape_buffers (ide_drive_t *drive)
2918 {
2919         idetape_pc_t pc;
2920         int rc;
2921
2922         idetape_create_write_filemark_cmd(drive, &pc, 0);
2923         if ((rc = idetape_queue_pc_tail(drive, &pc)))
2924                 return rc;
2925         idetape_wait_ready(drive, 60 * 5 * HZ);
2926         return 0;
2927 }
2928
2929 static void idetape_create_read_position_cmd (idetape_pc_t *pc)
2930 {
2931         idetape_init_pc(pc);
2932         pc->c[0] = IDETAPE_READ_POSITION_CMD;
2933         pc->request_transfer = 20;
2934         pc->callback = &idetape_read_position_callback;
2935 }
2936
2937 static int idetape_read_position (ide_drive_t *drive)
2938 {
2939         idetape_tape_t *tape = drive->driver_data;
2940         idetape_pc_t pc;
2941         int position;
2942
2943 #if IDETAPE_DEBUG_LOG
2944         if (tape->debug_level >= 4)
2945                 printk(KERN_INFO "ide-tape: Reached idetape_read_position\n");
2946 #endif /* IDETAPE_DEBUG_LOG */
2947
2948         idetape_create_read_position_cmd(&pc);
2949         if (idetape_queue_pc_tail(drive, &pc))
2950                 return -1;
2951         position = tape->first_frame_position;
2952         return position;
2953 }
2954
2955 static void idetape_create_locate_cmd (ide_drive_t *drive, idetape_pc_t *pc, unsigned int block, u8 partition, int skip)
2956 {
2957         idetape_init_pc(pc);
2958         pc->c[0] = IDETAPE_LOCATE_CMD;
2959         pc->c[1] = 2;
2960         put_unaligned(htonl(block), (unsigned int *) &pc->c[3]);
2961         pc->c[8] = partition;
2962         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2963         pc->callback = &idetape_pc_callback;
2964 }
2965
2966 static int idetape_create_prevent_cmd (ide_drive_t *drive, idetape_pc_t *pc, int prevent)
2967 {
2968         idetape_tape_t *tape = drive->driver_data;
2969
2970         if (!tape->capabilities.lock)
2971                 return 0;
2972
2973         idetape_init_pc(pc);
2974         pc->c[0] = IDETAPE_PREVENT_CMD;
2975         pc->c[4] = prevent;
2976         pc->callback = &idetape_pc_callback;
2977         return 1;
2978 }
2979
2980 static int __idetape_discard_read_pipeline (ide_drive_t *drive)
2981 {
2982         idetape_tape_t *tape = drive->driver_data;
2983         unsigned long flags;
2984         int cnt;
2985
2986         if (tape->chrdev_direction != idetape_direction_read)
2987                 return 0;
2988
2989         /* Remove merge stage. */
2990         cnt = tape->merge_stage_size / tape->tape_block_size;
2991         if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
2992                 ++cnt;          /* Filemarks count as 1 sector */
2993         tape->merge_stage_size = 0;
2994         if (tape->merge_stage != NULL) {
2995                 __idetape_kfree_stage(tape->merge_stage);
2996                 tape->merge_stage = NULL;
2997         }
2998
2999         /* Clear pipeline flags. */
3000         clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
3001         tape->chrdev_direction = idetape_direction_none;
3002
3003         /* Remove pipeline stages. */
3004         if (tape->first_stage == NULL)
3005                 return 0;
3006
3007         spin_lock_irqsave(&tape->spinlock, flags);
3008         tape->next_stage = NULL;
3009         if (idetape_pipeline_active(tape))
3010                 idetape_wait_for_request(drive, tape->active_data_request);
3011         spin_unlock_irqrestore(&tape->spinlock, flags);
3012
3013         while (tape->first_stage != NULL) {
3014                 struct request *rq_ptr = &tape->first_stage->rq;
3015
3016                 cnt += rq_ptr->nr_sectors - rq_ptr->current_nr_sectors; 
3017                 if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
3018                         ++cnt;
3019                 idetape_remove_stage_head(drive);
3020         }
3021         tape->nr_pending_stages = 0;
3022         tape->max_stages = tape->min_pipeline;
3023         return cnt;
3024 }
3025
3026 /*
3027  *      idetape_position_tape positions the tape to the requested block
3028  *      using the LOCATE packet command. A READ POSITION command is then
3029  *      issued to check where we are positioned.
3030  *
3031  *      Like all higher level operations, we queue the commands at the tail
3032  *      of the request queue and wait for their completion.
3033  *      
3034  */
3035 static int idetape_position_tape (ide_drive_t *drive, unsigned int block, u8 partition, int skip)
3036 {
3037         idetape_tape_t *tape = drive->driver_data;
3038         int retval;
3039         idetape_pc_t pc;
3040
3041         if (tape->chrdev_direction == idetape_direction_read)
3042                 __idetape_discard_read_pipeline(drive);
3043         idetape_wait_ready(drive, 60 * 5 * HZ);
3044         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
3045         retval = idetape_queue_pc_tail(drive, &pc);
3046         if (retval)
3047                 return (retval);
3048
3049         idetape_create_read_position_cmd(&pc);
3050         return (idetape_queue_pc_tail(drive, &pc));
3051 }
3052
3053 static void idetape_discard_read_pipeline (ide_drive_t *drive, int restore_position)
3054 {
3055         idetape_tape_t *tape = drive->driver_data;
3056         int cnt;
3057         int seek, position;
3058
3059         cnt = __idetape_discard_read_pipeline(drive);
3060         if (restore_position) {
3061                 position = idetape_read_position(drive);
3062                 seek = position > cnt ? position - cnt : 0;
3063                 if (idetape_position_tape(drive, seek, 0, 0)) {
3064                         printk(KERN_INFO "ide-tape: %s: position_tape failed in discard_pipeline()\n", tape->name);
3065                         return;
3066                 }
3067         }
3068 }
3069
3070 /*
3071  * idetape_queue_rw_tail generates a read/write request for the block
3072  * device interface and wait for it to be serviced.
3073  */
3074 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh)
3075 {
3076         idetape_tape_t *tape = drive->driver_data;
3077         struct request rq;
3078
3079 #if IDETAPE_DEBUG_LOG
3080         if (tape->debug_level >= 2)
3081                 printk(KERN_INFO "ide-tape: idetape_queue_rw_tail: cmd=%d\n",cmd);
3082 #endif /* IDETAPE_DEBUG_LOG */
3083 #if IDETAPE_DEBUG_BUGS
3084         if (idetape_pipeline_active(tape)) {
3085                 printk(KERN_ERR "ide-tape: bug: the pipeline is active in idetape_queue_rw_tail\n");
3086                 return (0);
3087         }
3088 #endif /* IDETAPE_DEBUG_BUGS */ 
3089
3090         idetape_init_rq(&rq, cmd);
3091         rq.rq_disk = tape->disk;
3092         rq.special = (void *)bh;
3093         rq.sector = tape->first_frame_position;
3094         rq.nr_sectors = rq.current_nr_sectors = blocks;
3095         (void) ide_do_drive_cmd(drive, &rq, ide_wait);
3096
3097         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
3098                 return 0;
3099
3100         if (tape->merge_stage)
3101                 idetape_init_merge_stage(tape);
3102         if (rq.errors == IDETAPE_ERROR_GENERAL)
3103                 return -EIO;
3104         return (tape->tape_block_size * (blocks-rq.current_nr_sectors));
3105 }
3106
3107 /*
3108  *      idetape_insert_pipeline_into_queue is used to start servicing the
3109  *      pipeline stages, starting from tape->next_stage.
3110  */
3111 static void idetape_insert_pipeline_into_queue (ide_drive_t *drive)
3112 {
3113         idetape_tape_t *tape = drive->driver_data;
3114
3115         if (tape->next_stage == NULL)
3116                 return;
3117         if (!idetape_pipeline_active(tape)) {
3118                 set_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
3119                 idetape_active_next_stage(drive);
3120                 (void) ide_do_drive_cmd(drive, tape->active_data_request, ide_end);
3121         }
3122 }
3123
3124 static void idetape_create_inquiry_cmd (idetape_pc_t *pc)
3125 {
3126         idetape_init_pc(pc);
3127         pc->c[0] = IDETAPE_INQUIRY_CMD;
3128         pc->c[4] = pc->request_transfer = 254;
3129         pc->callback = &idetape_pc_callback;
3130 }
3131
3132 static void idetape_create_rewind_cmd (ide_drive_t *drive, idetape_pc_t *pc)
3133 {
3134         idetape_init_pc(pc);
3135         pc->c[0] = IDETAPE_REWIND_CMD;
3136         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3137         pc->callback = &idetape_pc_callback;
3138 }
3139
3140 #if 0
3141 static void idetape_create_mode_select_cmd (idetape_pc_t *pc, int length)
3142 {
3143         idetape_init_pc(pc);
3144         set_bit(PC_WRITING, &pc->flags);
3145         pc->c[0] = IDETAPE_MODE_SELECT_CMD;
3146         pc->c[1] = 0x10;
3147         put_unaligned(htons(length), (unsigned short *) &pc->c[3]);
3148         pc->request_transfer = 255;
3149         pc->callback = &idetape_pc_callback;
3150 }
3151 #endif
3152
3153 static void idetape_create_erase_cmd (idetape_pc_t *pc)
3154 {
3155         idetape_init_pc(pc);
3156         pc->c[0] = IDETAPE_ERASE_CMD;
3157         pc->c[1] = 1;
3158         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3159         pc->callback = &idetape_pc_callback;
3160 }
3161
3162 static void idetape_create_space_cmd (idetape_pc_t *pc,int count, u8 cmd)
3163 {
3164         idetape_init_pc(pc);
3165         pc->c[0] = IDETAPE_SPACE_CMD;
3166         put_unaligned(htonl(count), (unsigned int *) &pc->c[1]);
3167         pc->c[1] = cmd;
3168         set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3169         pc->callback = &idetape_pc_callback;
3170 }
3171
3172 static void idetape_wait_first_stage (ide_drive_t *drive)
3173 {
3174         idetape_tape_t *tape = drive->driver_data;
3175         unsigned long flags;
3176
3177         if (tape->first_stage == NULL)
3178                 return;
3179         spin_lock_irqsave(&tape->spinlock, flags);
3180         if (tape->active_stage == tape->first_stage)
3181                 idetape_wait_for_request(drive, tape->active_data_request);
3182         spin_unlock_irqrestore(&tape->spinlock, flags);
3183 }
3184
3185 /*
3186  *      idetape_add_chrdev_write_request tries to add a character device
3187  *      originated write request to our pipeline. In case we don't succeed,
3188  *      we revert to non-pipelined operation mode for this request.
3189  *
3190  *      1.      Try to allocate a new pipeline stage.
3191  *      2.      If we can't, wait for more and more requests to be serviced
3192  *              and try again each time.
3193  *      3.      If we still can't allocate a stage, fallback to
3194  *              non-pipelined operation mode for this request.
3195  */
3196 static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
3197 {
3198         idetape_tape_t *tape = drive->driver_data;
3199         idetape_stage_t *new_stage;
3200         unsigned long flags;
3201         struct request *rq;
3202
3203 #if IDETAPE_DEBUG_LOG
3204         if (tape->debug_level >= 3)
3205                 printk(KERN_INFO "ide-tape: Reached idetape_add_chrdev_write_request\n");
3206 #endif /* IDETAPE_DEBUG_LOG */
3207
3208         /*
3209          *      Attempt to allocate a new stage.
3210          *      Pay special attention to possible race conditions.
3211          */
3212         while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
3213                 spin_lock_irqsave(&tape->spinlock, flags);
3214                 if (idetape_pipeline_active(tape)) {
3215                         idetape_wait_for_request(drive, tape->active_data_request);
3216                         spin_unlock_irqrestore(&tape->spinlock, flags);
3217                 } else {
3218                         spin_unlock_irqrestore(&tape->spinlock, flags);
3219                         idetape_insert_pipeline_into_queue(drive);
3220                         if (idetape_pipeline_active(tape))
3221                                 continue;
3222                         /*
3223                          *      Linux is short on memory. Fallback to
3224                          *      non-pipelined operation mode for this request.
3225                          */
3226                         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
3227                 }
3228         }
3229         rq = &new_stage->rq;
3230         idetape_init_rq(rq, REQ_IDETAPE_WRITE);
3231         /* Doesn't actually matter - We always assume sequential access */
3232         rq->sector = tape->first_frame_position;
3233         rq->nr_sectors = rq->current_nr_sectors = blocks;
3234
3235         idetape_switch_buffers(tape, new_stage);
3236         idetape_add_stage_tail(drive, new_stage);
3237         tape->pipeline_head++;
3238 #if USE_IOTRACE
3239         IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
3240 #endif
3241         calculate_speeds(drive);
3242
3243         /*
3244          *      Estimate whether the tape has stopped writing by checking
3245          *      if our write pipeline is currently empty. If we are not
3246          *      writing anymore, wait for the pipeline to be full enough
3247          *      (90%) before starting to service requests, so that we will
3248          *      be able to keep up with the higher speeds of the tape.
3249          */
3250         if (!idetape_pipeline_active(tape)) {
3251                 if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
3252                     tape->nr_stages >= tape->max_stages - tape->uncontrolled_pipeline_head_speed * 3 * 1024 / tape->tape_block_size) {
3253                         tape->measure_insert_time = 1;
3254                         tape->insert_time = jiffies;
3255                         tape->insert_size = 0;
3256                         tape->insert_speed = 0;
3257                         idetape_insert_pipeline_into_queue(drive);
3258                 }
3259         }
3260         if (test_and_clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
3261                 /* Return a deferred error */
3262                 return -EIO;
3263         return blocks;
3264 }
3265
3266 /*
3267  *      idetape_wait_for_pipeline will wait until all pending pipeline
3268  *      requests are serviced. Typically called on device close.
3269  */
3270 static void idetape_wait_for_pipeline (ide_drive_t *drive)
3271 {
3272         idetape_tape_t *tape = drive->driver_data;
3273         unsigned long flags;
3274
3275         while (tape->next_stage || idetape_pipeline_active(tape)) {
3276                 idetape_insert_pipeline_into_queue(drive);
3277                 spin_lock_irqsave(&tape->spinlock, flags);
3278                 if (idetape_pipeline_active(tape))
3279                         idetape_wait_for_request(drive, tape->active_data_request);
3280                 spin_unlock_irqrestore(&tape->spinlock, flags);
3281         }
3282 }
3283
3284 static void idetape_empty_write_pipeline (ide_drive_t *drive)
3285 {
3286         idetape_tape_t *tape = drive->driver_data;
3287         int blocks, min;
3288         struct idetape_bh *bh;
3289         
3290 #if IDETAPE_DEBUG_BUGS
3291         if (tape->chrdev_direction != idetape_direction_write) {
3292                 printk(KERN_ERR "ide-tape: bug: Trying to empty write pipeline, but we are not writing.\n");
3293                 return;
3294         }
3295         if (tape->merge_stage_size > tape->stage_size) {
3296                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
3297                 tape->merge_stage_size = tape->stage_size;
3298         }
3299 #endif /* IDETAPE_DEBUG_BUGS */
3300         if (tape->merge_stage_size) {
3301                 blocks = tape->merge_stage_size / tape->tape_block_size;
3302                 if (tape->merge_stage_size % tape->tape_block_size) {
3303                         unsigned int i;
3304
3305                         blocks++;
3306                         i = tape->tape_block_size - tape->merge_stage_size % tape->tape_block_size;
3307                         bh = tape->bh->b_reqnext;
3308                         while (bh) {
3309                                 atomic_set(&bh->b_count, 0);
3310                                 bh = bh->b_reqnext;
3311                         }
3312                         bh = tape->bh;
3313                         while (i) {
3314                                 if (bh == NULL) {
3315
3316                                         printk(KERN_INFO "ide-tape: bug, bh NULL\n");
3317                                         break;
3318                                 }
3319                                 min = min(i, (unsigned int)(bh->b_size - atomic_read(&bh->b_count)));
3320                                 memset(bh->b_data + atomic_read(&bh->b_count), 0, min);
3321                                 atomic_add(min, &bh->b_count);
3322                                 i -= min;
3323                                 bh = bh->b_reqnext;
3324                         }
3325                 }
3326                 (void) idetape_add_chrdev_write_request(drive, blocks);
3327                 tape->merge_stage_size = 0;
3328         }
3329         idetape_wait_for_pipeline(drive);
3330         if (tape->merge_stage != NULL) {
3331                 __idetape_kfree_stage(tape->merge_stage);
3332                 tape->merge_stage = NULL;
3333         }
3334         clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
3335         tape->chrdev_direction = idetape_direction_none;
3336
3337         /*
3338          *      On the next backup, perform the feedback loop again.
3339          *      (I don't want to keep sense information between backups,
3340          *       as some systems are constantly on, and the system load
3341          *       can be totally different on the next backup).
3342          */
3343         tape->max_stages = tape->min_pipeline;
3344 #if IDETAPE_DEBUG_BUGS
3345         if (tape->first_stage != NULL ||
3346             tape->next_stage != NULL ||
3347             tape->last_stage != NULL ||
3348             tape->nr_stages != 0) {
3349                 printk(KERN_ERR "ide-tape: ide-tape pipeline bug, "
3350                         "first_stage %p, next_stage %p, "
3351                         "last_stage %p, nr_stages %d\n",
3352                         tape->first_stage, tape->next_stage,
3353                         tape->last_stage, tape->nr_stages);
3354         }
3355 #endif /* IDETAPE_DEBUG_BUGS */
3356 }
3357
3358 static void idetape_restart_speed_control (ide_drive_t *drive)
3359 {
3360         idetape_tape_t *tape = drive->driver_data;
3361
3362         tape->restart_speed_control_req = 0;
3363         tape->pipeline_head = 0;
3364         tape->controlled_last_pipeline_head = tape->uncontrolled_last_pipeline_head = 0;
3365         tape->controlled_previous_pipeline_head = tape->uncontrolled_previous_pipeline_head = 0;
3366         tape->pipeline_head_speed = tape->controlled_pipeline_head_speed = 5000;
3367         tape->uncontrolled_pipeline_head_speed = 0;
3368         tape->controlled_pipeline_head_time = tape->uncontrolled_pipeline_head_time = jiffies;
3369         tape->controlled_previous_head_time = tape->uncontrolled_previous_head_time = jiffies;
3370 }
3371
3372 static int idetape_initiate_read (ide_drive_t *drive, int max_stages)
3373 {
3374         idetape_tape_t *tape = drive->driver_data;
3375         idetape_stage_t *new_stage;
3376         struct request rq;
3377         int bytes_read;
3378         int blocks = tape->capabilities.ctl;
3379
3380         /* Initialize read operation */
3381         if (tape->chrdev_direction != idetape_direction_read) {
3382                 if (tape->chrdev_direction == idetape_direction_write) {
3383                         idetape_empty_write_pipeline(drive);
3384                         idetape_flush_tape_buffers(drive);
3385                 }
3386 #if IDETAPE_DEBUG_BUGS
3387                 if (tape->merge_stage || tape->merge_stage_size) {
3388                         printk (KERN_ERR "ide-tape: merge_stage_size should be 0 now\n");
3389                         tape->merge_stage_size = 0;
3390                 }
3391 #endif /* IDETAPE_DEBUG_BUGS */
3392                 if ((tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0)) == NULL)
3393                         return -ENOMEM;
3394                 tape->chrdev_direction = idetape_direction_read;
3395
3396                 /*
3397                  *      Issue a read 0 command to ensure that DSC handshake
3398                  *      is switched from completion mode to buffer available
3399                  *      mode.
3400                  *      No point in issuing this if DSC overlap isn't supported,
3401                  *      some drives (Seagate STT3401A) will return an error.
3402                  */
3403                 if (drive->dsc_overlap) {
3404                         bytes_read = idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 0, tape->merge_stage->bh);
3405                         if (bytes_read < 0) {
3406                                 __idetape_kfree_stage(tape->merge_stage);
3407                                 tape->merge_stage = NULL;
3408                                 tape->chrdev_direction = idetape_direction_none;
3409                                 return bytes_read;
3410                         }
3411                 }
3412         }
3413         if (tape->restart_speed_control_req)
3414                 idetape_restart_speed_control(drive);
3415         idetape_init_rq(&rq, REQ_IDETAPE_READ);
3416         rq.sector = tape->first_frame_position;
3417         rq.nr_sectors = rq.current_nr_sectors = blocks;
3418         if (!test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags) &&
3419             tape->nr_stages < max_stages) {
3420                 new_stage = idetape_kmalloc_stage(tape);
3421                 while (new_stage != NULL) {
3422                         new_stage->rq = rq;
3423                         idetape_add_stage_tail(drive, new_stage);
3424                         if (tape->nr_stages >= max_stages)
3425                                 break;
3426                         new_stage = idetape_kmalloc_stage(tape);
3427                 }
3428         }
3429         if (!idetape_pipeline_active(tape)) {
3430                 if (tape->nr_pending_stages >= 3 * max_stages / 4) {
3431                         tape->measure_insert_time = 1;
3432                         tape->insert_time = jiffies;
3433                         tape->insert_size = 0;
3434                         tape->insert_speed = 0;
3435                         idetape_insert_pipeline_into_queue(drive);
3436                 }
3437         }
3438         return 0;
3439 }
3440
3441 /*
3442  *      idetape_add_chrdev_read_request is called from idetape_chrdev_read
3443  *      to service a character device read request and add read-ahead
3444  *      requests to our pipeline.
3445  */
3446 static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
3447 {
3448         idetape_tape_t *tape = drive->driver_data;
3449         unsigned long flags;
3450         struct request *rq_ptr;
3451         int bytes_read;
3452
3453 #if IDETAPE_DEBUG_LOG
3454         if (tape->debug_level >= 4)
3455                 printk(KERN_INFO "ide-tape: Reached idetape_add_chrdev_read_request, %d blocks\n", blocks);
3456 #endif /* IDETAPE_DEBUG_LOG */
3457
3458         /*
3459          * If we are at a filemark, return a read length of 0
3460          */
3461         if (test_bit(IDETAPE_FILEMARK, &tape->flags))
3462                 return 0;
3463
3464         /*
3465          * Wait for the next block to be available at the head
3466          * of the pipeline
3467          */
3468         idetape_initiate_read(drive, tape->max_stages);
3469         if (tape->first_stage == NULL) {
3470                 if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
3471                         return 0;
3472                 return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks, tape->merge_stage->bh);
3473         }
3474         idetape_wait_first_stage(drive);
3475         rq_ptr = &tape->first_stage->rq;
3476         bytes_read = tape->tape_block_size * (rq_ptr->nr_sectors - rq_ptr->current_nr_sectors);
3477         rq_ptr->nr_sectors = rq_ptr->current_nr_sectors = 0;
3478
3479
3480         if (rq_ptr->errors == IDETAPE_ERROR_EOD)
3481                 return 0;
3482         else {
3483                 idetape_switch_buffers(tape, tape->first_stage);
3484                 if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
3485                         set_bit(IDETAPE_FILEMARK, &tape->flags);
3486                 spin_lock_irqsave(&tape->spinlock, flags);
3487                 idetape_remove_stage_head(drive);
3488                 spin_unlock_irqrestore(&tape->spinlock, flags);
3489                 tape->pipeline_head++;
3490 #if USE_IOTRACE
3491                 IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
3492 #endif
3493                 calculate_speeds(drive);
3494         }
3495 #if IDETAPE_DEBUG_BUGS
3496         if (bytes_read > blocks * tape->tape_block_size) {
3497                 printk(KERN_ERR "ide-tape: bug: trying to return more bytes than requested\n");
3498                 bytes_read = blocks * tape->tape_block_size;
3499         }
3500 #endif /* IDETAPE_DEBUG_BUGS */
3501         return (bytes_read);
3502 }
3503
3504 static void idetape_pad_zeros (ide_drive_t *drive, int bcount)
3505 {
3506         idetape_tape_t *tape = drive->driver_data;
3507         struct idetape_bh *bh;
3508         int blocks;
3509         
3510         while (bcount) {
3511                 unsigned int count;
3512
3513                 bh = tape->merge_stage->bh;
3514                 count = min(tape->stage_size, bcount);
3515                 bcount -= count;
3516                 blocks = count / tape->tape_block_size;
3517                 while (count) {
3518                         atomic_set(&bh->b_count, min(count, (unsigned int)bh->b_size));
3519                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
3520                         count -= atomic_read(&bh->b_count);
3521                         bh = bh->b_reqnext;
3522                 }
3523                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
3524         }
3525 }
3526
3527 static int idetape_pipeline_size (ide_drive_t *drive)
3528 {
3529         idetape_tape_t *tape = drive->driver_data;
3530         idetape_stage_t *stage;
3531         struct request *rq;
3532         int size = 0;
3533
3534         idetape_wait_for_pipeline(drive);
3535         stage = tape->first_stage;
3536         while (stage != NULL) {
3537                 rq = &stage->rq;
3538                 size += tape->tape_block_size * (rq->nr_sectors-rq->current_nr_sectors);
3539                 if (rq->errors == IDETAPE_ERROR_FILEMARK)
3540                         size += tape->tape_block_size;
3541                 stage = stage->next;
3542         }
3543         size += tape->merge_stage_size;
3544         return size;
3545 }
3546
3547 /*
3548  *      Rewinds the tape to the Beginning Of the current Partition (BOP).
3549  *
3550  *      We currently support only one partition.
3551  */ 
3552 static int idetape_rewind_tape (ide_drive_t *drive)
3553 {
3554         int retval;
3555         idetape_pc_t pc;
3556 #if IDETAPE_DEBUG_LOG
3557         idetape_tape_t *tape = drive->driver_data;
3558         if (tape->debug_level >= 2)
3559                 printk(KERN_INFO "ide-tape: Reached idetape_rewind_tape\n");
3560 #endif /* IDETAPE_DEBUG_LOG */  
3561         
3562         idetape_create_rewind_cmd(drive, &pc);
3563         retval = idetape_queue_pc_tail(drive, &pc);
3564         if (retval)
3565                 return retval;
3566
3567         idetape_create_read_position_cmd(&pc);
3568         retval = idetape_queue_pc_tail(drive, &pc);
3569         if (retval)
3570                 return retval;
3571         return 0;
3572 }
3573
3574 /*
3575  *      Our special ide-tape ioctl's.
3576  *
3577  *      Currently there aren't any ioctl's.
3578  *      mtio.h compatible commands should be issued to the character device
3579  *      interface.
3580  */
3581 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned long arg)
3582 {
3583         idetape_tape_t *tape = drive->driver_data;
3584         idetape_config_t config;
3585         void __user *argp = (void __user *)arg;
3586
3587 #if IDETAPE_DEBUG_LOG   
3588         if (tape->debug_level >= 4)
3589                 printk(KERN_INFO "ide-tape: Reached idetape_blkdev_ioctl\n");
3590 #endif /* IDETAPE_DEBUG_LOG */
3591         switch (cmd) {
3592                 case 0x0340:
3593                         if (copy_from_user(&config, argp, sizeof (idetape_config_t)))
3594                                 return -EFAULT;
3595                         tape->best_dsc_rw_frequency = config.dsc_rw_frequency;
3596                         tape->max_stages = config.nr_stages;
3597                         break;
3598                 case 0x0350:
3599                         config.dsc_rw_frequency = (int) tape->best_dsc_rw_frequency;
3600                         config.nr_stages = tape->max_stages; 
3601                         if (copy_to_user(argp, &config, sizeof (idetape_config_t)))
3602                                 return -EFAULT;
3603                         break;
3604                 default:
3605                         return -EIO;
3606         }
3607         return 0;
3608 }
3609
3610 /*
3611  *      idetape_space_over_filemarks is now a bit more complicated than just
3612  *      passing the command to the tape since we may have crossed some
3613  *      filemarks during our pipelined read-ahead mode.
3614  *
3615  *      As a minor side effect, the pipeline enables us to support MTFSFM when
3616  *      the filemark is in our internal pipeline even if the tape doesn't
3617  *      support spacing over filemarks in the reverse direction.
3618  */
3619 static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_count)
3620 {
3621         idetape_tape_t *tape = drive->driver_data;
3622         idetape_pc_t pc;
3623         unsigned long flags;
3624         int retval,count=0;
3625
3626         if (mt_count == 0)
3627                 return 0;
3628         if (MTBSF == mt_op || MTBSFM == mt_op) {
3629                 if (!tape->capabilities.sprev)
3630                         return -EIO;
3631                 mt_count = - mt_count;
3632         }
3633
3634         if (tape->chrdev_direction == idetape_direction_read) {
3635                 /*
3636                  *      We have a read-ahead buffer. Scan it for crossed
3637                  *      filemarks.
3638                  */
3639                 tape->merge_stage_size = 0;
3640                 if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
3641                         ++count;
3642                 while (tape->first_stage != NULL) {
3643                         if (count == mt_count) {
3644                                 if (mt_op == MTFSFM)
3645                                         set_bit(IDETAPE_FILEMARK, &tape->flags);
3646                                 return 0;
3647                         }
3648                         spin_lock_irqsave(&tape->spinlock, flags);
3649                         if (tape->first_stage == tape->active_stage) {
3650                                 /*
3651                                  *      We have reached the active stage in the read pipeline.
3652                                  *      There is no point in allowing the drive to continue
3653                                  *      reading any farther, so we stop the pipeline.
3654                                  *
3655                                  *      This section should be moved to a separate subroutine,
3656                                  *      because a similar function is performed in
3657                                  *      __idetape_discard_read_pipeline(), for example.
3658                                  */
3659                                 tape->next_stage = NULL;
3660                                 spin_unlock_irqrestore(&tape->spinlock, flags);
3661                                 idetape_wait_first_stage(drive);
3662                                 tape->next_stage = tape->first_stage->next;
3663                         } else
3664                                 spin_unlock_irqrestore(&tape->spinlock, flags);
3665                         if (tape->first_stage->rq.errors == IDETAPE_ERROR_FILEMARK)
3666                                 ++count;
3667                         idetape_remove_stage_head(drive);
3668                 }
3669                 idetape_discard_read_pipeline(drive, 0);
3670         }
3671
3672         /*
3673          *      The filemark was not found in our internal pipeline.
3674          *      Now we can issue the space command.
3675          */
3676         switch (mt_op) {
3677                 case MTFSF:
3678                 case MTBSF:
3679                         idetape_create_space_cmd(&pc,mt_count-count,IDETAPE_SPACE_OVER_FILEMARK);
3680                         return (idetape_queue_pc_tail(drive, &pc));
3681                 case MTFSFM:
3682                 case MTBSFM:
3683                         if (!tape->capabilities.sprev)
3684                                 return (-EIO);
3685                         retval = idetape_space_over_filemarks(drive, MTFSF, mt_count-count);
3686                         if (retval) return (retval);
3687                         count = (MTBSFM == mt_op ? 1 : -1);
3688                         return (idetape_space_over_filemarks(drive, MTFSF, count));
3689                 default:
3690                         printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",mt_op);
3691                         return (-EIO);
3692         }
3693 }
3694
3695
3696 /*
3697  *      Our character device read / write functions.
3698  *
3699  *      The tape is optimized to maximize throughput when it is transferring
3700  *      an integral number of the "continuous transfer limit", which is
3701  *      a parameter of the specific tape (26 KB on my particular tape).
3702  *      (32 kB for Onstream)
3703  *
3704  *      As of version 1.3 of the driver, the character device provides an
3705  *      abstract continuous view of the media - any mix of block sizes (even 1
3706  *      byte) on the same backup/restore procedure is supported. The driver
3707  *      will internally convert the requests to the recommended transfer unit,
3708  *      so that an unmatch between the user's block size to the recommended
3709  *      size will only result in a (slightly) increased driver overhead, but
3710  *      will no longer hit performance.
3711  *      This is not applicable to Onstream.
3712  */
3713 static ssize_t idetape_chrdev_read (struct file *file, char __user *buf,
3714                                     size_t count, loff_t *ppos)
3715 {
3716         struct ide_tape_obj *tape = ide_tape_f(file);
3717         ide_drive_t *drive = tape->drive;
3718         ssize_t bytes_read,temp, actually_read = 0, rc;
3719
3720 #if IDETAPE_DEBUG_LOG
3721         if (tape->debug_level >= 3)
3722                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_read, count %Zd\n", count);
3723 #endif /* IDETAPE_DEBUG_LOG */
3724
3725         if (tape->chrdev_direction != idetape_direction_read) {
3726                 if (test_bit(IDETAPE_DETECT_BS, &tape->flags))
3727                         if (count > tape->tape_block_size &&
3728                             (count % tape->tape_block_size) == 0)
3729                                 tape->user_bs_factor = count / tape->tape_block_size;
3730         }
3731         if ((rc = idetape_initiate_read(drive, tape->max_stages)) < 0)
3732                 return rc;
3733         if (count == 0)
3734                 return (0);
3735         if (tape->merge_stage_size) {
3736                 actually_read = min((unsigned int)(tape->merge_stage_size), (unsigned int)count);
3737                 idetape_copy_stage_to_user(tape, buf, tape->merge_stage, actually_read);
3738                 buf += actually_read;
3739                 tape->merge_stage_size -= actually_read;
3740                 count -= actually_read;
3741         }
3742         while (count >= tape->stage_size) {
3743                 bytes_read = idetape_add_chrdev_read_request(drive, tape->capabilities.ctl);
3744                 if (bytes_read <= 0)
3745                         goto finish;
3746                 idetape_copy_stage_to_user(tape, buf, tape->merge_stage, bytes_read);
3747                 buf += bytes_read;
3748                 count -= bytes_read;
3749                 actually_read += bytes_read;
3750         }
3751         if (count) {
3752                 bytes_read = idetape_add_chrdev_read_request(drive, tape->capabilities.ctl);
3753                 if (bytes_read <= 0)
3754                         goto finish;
3755                 temp = min((unsigned long)count, (unsigned long)bytes_read);
3756                 idetape_copy_stage_to_user(tape, buf, tape->merge_stage, temp);
3757                 actually_read += temp;
3758                 tape->merge_stage_size = bytes_read-temp;
3759         }
3760 finish:
3761         if (!actually_read && test_bit(IDETAPE_FILEMARK, &tape->flags)) {
3762 #if IDETAPE_DEBUG_LOG
3763                 if (tape->debug_level >= 2)
3764                         printk(KERN_INFO "ide-tape: %s: spacing over filemark\n", tape->name);
3765 #endif
3766                 idetape_space_over_filemarks(drive, MTFSF, 1);
3767                 return 0;
3768         }
3769         return actually_read;
3770 }
3771
3772 static ssize_t idetape_chrdev_write (struct file *file, const char __user *buf,
3773                                      size_t count, loff_t *ppos)
3774 {
3775         struct ide_tape_obj *tape = ide_tape_f(file);
3776         ide_drive_t *drive = tape->drive;
3777         ssize_t retval, actually_written = 0;
3778
3779         /* The drive is write protected. */
3780         if (tape->write_prot)
3781                 return -EACCES;
3782
3783 #if IDETAPE_DEBUG_LOG
3784         if (tape->debug_level >= 3)
3785                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_write, "
3786                         "count %Zd\n", count);
3787 #endif /* IDETAPE_DEBUG_LOG */
3788
3789         /* Initialize write operation */
3790         if (tape->chrdev_direction != idetape_direction_write) {
3791                 if (tape->chrdev_direction == idetape_direction_read)
3792                         idetape_discard_read_pipeline(drive, 1);
3793 #if IDETAPE_DEBUG_BUGS
3794                 if (tape->merge_stage || tape->merge_stage_size) {
3795                         printk(KERN_ERR "ide-tape: merge_stage_size "
3796                                 "should be 0 now\n");
3797                         tape->merge_stage_size = 0;
3798                 }
3799 #endif /* IDETAPE_DEBUG_BUGS */
3800                 if ((tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0)) == NULL)
3801                         return -ENOMEM;
3802                 tape->chrdev_direction = idetape_direction_write;
3803                 idetape_init_merge_stage(tape);
3804
3805                 /*
3806                  *      Issue a write 0 command to ensure that DSC handshake
3807                  *      is switched from completion mode to buffer available
3808                  *      mode.
3809                  *      No point in issuing this if DSC overlap isn't supported,
3810                  *      some drives (Seagate STT3401A) will return an error.
3811                  */
3812                 if (drive->dsc_overlap) {
3813                         retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh);
3814                         if (retval < 0) {
3815                                 __idetape_kfree_stage(tape->merge_stage);
3816                                 tape->merge_stage = NULL;
3817                                 tape->chrdev_direction = idetape_direction_none;
3818                                 return retval;
3819                         }
3820                 }
3821         }
3822         if (count == 0)
3823                 return (0);
3824         if (tape->restart_speed_control_req)
3825                 idetape_restart_speed_control(drive);
3826         if (tape->merge_stage_size) {
3827 #if IDETAPE_DEBUG_BUGS
3828                 if (tape->merge_stage_size >= tape->stage_size) {
3829                         printk(KERN_ERR "ide-tape: bug: merge buffer too big\n");
3830                         tape->merge_stage_size = 0;
3831                 }
3832 #endif /* IDETAPE_DEBUG_BUGS */
3833                 actually_written = min((unsigned int)(tape->stage_size - tape->merge_stage_size), (unsigned int)count);
3834                 idetape_copy_stage_from_user(tape, tape->merge_stage, buf, actually_written);
3835                 buf += actually_written;
3836                 tape->merge_stage_size += actually_written;
3837                 count -= actually_written;
3838
3839                 if (tape->merge_stage_size == tape->stage_size) {
3840                         tape->merge_stage_size = 0;
3841                         retval = idetape_add_chrdev_write_request(drive, tape->capabilities.ctl);
3842                         if (retval <= 0)
3843                                 return (retval);
3844                 }
3845         }
3846         while (count >= tape->stage_size) {
3847                 idetape_copy_stage_from_user(tape, tape->merge_stage, buf, tape->stage_size);
3848                 buf += tape->stage_size;
3849                 count -= tape->stage_size;
3850                 retval = idetape_add_chrdev_write_request(drive, tape->capabilities.ctl);
3851                 actually_written += tape->stage_size;
3852                 if (retval <= 0)
3853                         return (retval);
3854         }
3855         if (count) {
3856                 actually_written += count;
3857                 idetape_copy_stage_from_user(tape, tape->merge_stage, buf, count);
3858                 tape->merge_stage_size += count;
3859         }
3860         return (actually_written);
3861 }
3862
3863 static int idetape_write_filemark (ide_drive_t *drive)
3864 {
3865         idetape_pc_t pc;
3866
3867         /* Write a filemark */
3868         idetape_create_write_filemark_cmd(drive, &pc, 1);
3869         if (idetape_queue_pc_tail(drive, &pc)) {
3870                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
3871                 return -EIO;
3872         }
3873         return 0;
3874 }
3875
3876 /*
3877  *      idetape_mtioctop is called from idetape_chrdev_ioctl when
3878  *      the general mtio MTIOCTOP ioctl is requested.
3879  *
3880  *      We currently support the following mtio.h operations:
3881  *
3882  *      MTFSF   -       Space over mt_count filemarks in the positive direction.
3883  *                      The tape is positioned after the last spaced filemark.
3884  *
3885  *      MTFSFM  -       Same as MTFSF, but the tape is positioned before the
3886  *                      last filemark.
3887  *
3888  *      MTBSF   -       Steps background over mt_count filemarks, tape is
3889  *                      positioned before the last filemark.
3890  *
3891  *      MTBSFM  -       Like MTBSF, only tape is positioned after the last filemark.
3892  *
3893  *      Note:
3894  *
3895  *              MTBSF and MTBSFM are not supported when the tape doesn't
3896  *              support spacing over filemarks in the reverse direction.
3897  *              In this case, MTFSFM is also usually not supported (it is
3898  *              supported in the rare case in which we crossed the filemark
3899  *              during our read-ahead pipelined operation mode).
3900  *              
3901  *      MTWEOF  -       Writes mt_count filemarks. Tape is positioned after
3902  *                      the last written filemark.
3903  *
3904  *      MTREW   -       Rewinds tape.
3905  *
3906  *      MTLOAD  -       Loads the tape.
3907  *
3908  *      MTOFFL  -       Puts the tape drive "Offline": Rewinds the tape and
3909  *      MTUNLOAD        prevents further access until the media is replaced.
3910  *
3911  *      MTNOP   -       Flushes tape buffers.
3912  *
3913  *      MTRETEN -       Retension media. This typically consists of one end
3914  *                      to end pass on the media.
3915  *
3916  *      MTEOM   -       Moves to the end of recorded data.
3917  *
3918  *      MTERASE -       Erases tape.
3919  *
3920  *      MTSETBLK -      Sets the user block size to mt_count bytes. If
3921  *                      mt_count is 0, we will attempt to autodetect
3922  *                      the block size.
3923  *
3924  *      MTSEEK  -       Positions the tape in a specific block number, where
3925  *                      each block is assumed to contain which user_block_size
3926  *                      bytes.
3927  *
3928  *      MTSETPART -     Switches to another tape partition.
3929  *
3930  *      MTLOCK -        Locks the tape door.
3931  *
3932  *      MTUNLOCK -      Unlocks the tape door.
3933  *
3934  *      The following commands are currently not supported:
3935  *
3936  *      MTFSS, MTBSS, MTWSM, MTSETDENSITY,
3937  *      MTSETDRVBUFFER, MT_ST_BOOLEANS, MT_ST_WRITE_THRESHOLD.
3938  */
3939 static int idetape_mtioctop (ide_drive_t *drive,short mt_op,int mt_count)
3940 {
3941         idetape_tape_t *tape = drive->driver_data;
3942         idetape_pc_t pc;
3943         int i,retval;
3944
3945 #if IDETAPE_DEBUG_LOG
3946         if (tape->debug_level >= 1)
3947                 printk(KERN_INFO "ide-tape: Handling MTIOCTOP ioctl: "
3948                         "mt_op=%d, mt_count=%d\n", mt_op, mt_count);
3949 #endif /* IDETAPE_DEBUG_LOG */
3950         /*
3951          *      Commands which need our pipelined read-ahead stages.
3952          */
3953         switch (mt_op) {
3954                 case MTFSF:
3955                 case MTFSFM:
3956                 case MTBSF:
3957                 case MTBSFM:
3958                         if (!mt_count)
3959                                 return (0);
3960                         return (idetape_space_over_filemarks(drive,mt_op,mt_count));
3961                 default:
3962                         break;
3963         }
3964         switch (mt_op) {
3965                 case MTWEOF:
3966                         if (tape->write_prot)
3967                                 return -EACCES;
3968                         idetape_discard_read_pipeline(drive, 1);
3969                         for (i = 0; i < mt_count; i++) {
3970                                 retval = idetape_write_filemark(drive);
3971                                 if (retval)
3972                                         return retval;
3973                         }
3974                         return (0);
3975                 case MTREW:
3976                         idetape_discard_read_pipeline(drive, 0);
3977                         if (idetape_rewind_tape(drive))
3978                                 return -EIO;
3979                         return 0;
3980                 case MTLOAD:
3981                         idetape_discard_read_pipeline(drive, 0);
3982                         idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
3983                         return (idetape_queue_pc_tail(drive, &pc));
3984                 case MTUNLOAD:
3985                 case MTOFFL:
3986                         /*
3987                          * If door is locked, attempt to unlock before
3988                          * attempting to eject.
3989                          */
3990                         if (tape->door_locked) {
3991                                 if (idetape_create_prevent_cmd(drive, &pc, 0))
3992                                         if (!idetape_queue_pc_tail(drive, &pc))
3993                                                 tape->door_locked = DOOR_UNLOCKED;
3994                         }
3995                         idetape_discard_read_pipeline(drive, 0);
3996                         idetape_create_load_unload_cmd(drive, &pc,!IDETAPE_LU_LOAD_MASK);
3997                         retval = idetape_queue_pc_tail(drive, &pc);
3998                         if (!retval)
3999                                 clear_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
4000                         return retval;
4001                 case MTNOP:
4002                         idetape_discard_read_pipeline(drive, 0);
4003                         return (idetape_flush_tape_buffers(drive));
4004                 case MTRETEN:
4005                         idetape_discard_read_pipeline(drive, 0);
4006                         idetape_create_load_unload_cmd(drive, &pc,IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
4007                         return (idetape_queue_pc_tail(drive, &pc));
4008                 case MTEOM:
4009                         idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
4010                         return (idetape_queue_pc_tail(drive, &pc));
4011                 case MTERASE:
4012                         (void) idetape_rewind_tape(drive);
4013                         idetape_create_erase_cmd(&pc);
4014                         return (idetape_queue_pc_tail(drive, &pc));
4015                 case MTSETBLK:
4016                         if (mt_count) {
4017                                 if (mt_count < tape->tape_block_size || mt_count % tape->tape_block_size)
4018                                         return -EIO;
4019                                 tape->user_bs_factor = mt_count / tape->tape_block_size;
4020                                 clear_bit(IDETAPE_DETECT_BS, &tape->flags);
4021                         } else
4022                                 set_bit(IDETAPE_DETECT_BS, &tape->flags);
4023                         return 0;
4024                 case MTSEEK:
4025                         idetape_discard_read_pipeline(drive, 0);
4026                         return idetape_position_tape(drive, mt_count * tape->user_bs_factor, tape->partition, 0);
4027                 case MTSETPART:
4028                         idetape_discard_read_pipeline(drive, 0);
4029                         return (idetape_position_tape(drive, 0, mt_count, 0));
4030                 case MTFSR:
4031                 case MTBSR:
4032                 case MTLOCK:
4033                         if (!idetape_create_prevent_cmd(drive, &pc, 1))
4034                                 return 0;
4035                         retval = idetape_queue_pc_tail(drive, &pc);
4036                         if (retval) return retval;
4037                         tape->door_locked = DOOR_EXPLICITLY_LOCKED;
4038                         return 0;
4039                 case MTUNLOCK:
4040                         if (!idetape_create_prevent_cmd(drive, &pc, 0))
4041                                 return 0;
4042                         retval = idetape_queue_pc_tail(drive, &pc);
4043                         if (retval) return retval;
4044                         tape->door_locked = DOOR_UNLOCKED;
4045                         return 0;
4046                 default:
4047                         printk(KERN_ERR "ide-tape: MTIO operation %d not "
4048                                 "supported\n", mt_op);
4049                         return (-EIO);
4050         }
4051 }
4052
4053 /*
4054  *      Our character device ioctls.
4055  *
4056  *      General mtio.h magnetic io commands are supported here, and not in
4057  *      the corresponding block interface.
4058  *
4059  *      The following ioctls are supported:
4060  *
4061  *      MTIOCTOP -      Refer to idetape_mtioctop for detailed description.
4062  *
4063  *      MTIOCGET -      The mt_dsreg field in the returned mtget structure
4064  *                      will be set to (user block size in bytes <<
4065  *                      MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK.
4066  *
4067  *                      The mt_blkno is set to the current user block number.
4068  *                      The other mtget fields are not supported.
4069  *
4070  *      MTIOCPOS -      The current tape "block position" is returned. We
4071  *                      assume that each block contains user_block_size
4072  *                      bytes.
4073  *
4074  *      Our own ide-tape ioctls are supported on both interfaces.
4075  */
4076 static int idetape_chrdev_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
4077 {
4078         struct ide_tape_obj *tape = ide_tape_f(file);
4079         ide_drive_t *drive = tape->drive;
4080         struct mtop mtop;
4081         struct mtget mtget;
4082         struct mtpos mtpos;
4083         int block_offset = 0, position = tape->first_frame_position;
4084         void __user *argp = (void __user *)arg;
4085
4086 #if IDETAPE_DEBUG_LOG
4087         if (tape->debug_level >= 3)
4088                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_ioctl, "
4089                         "cmd=%u\n", cmd);
4090 #endif /* IDETAPE_DEBUG_LOG */
4091
4092         tape->restart_speed_control_req = 1;
4093         if (tape->chrdev_direction == idetape_direction_write) {
4094                 idetape_empty_write_pipeline(drive);
4095                 idetape_flush_tape_buffers(drive);
4096         }
4097         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
4098                 block_offset = idetape_pipeline_size(drive) / (tape->tape_block_size * tape->user_bs_factor);
4099                 if ((position = idetape_read_position(drive)) < 0)
4100                         return -EIO;
4101         }
4102         switch (cmd) {
4103                 case MTIOCTOP:
4104                         if (copy_from_user(&mtop, argp, sizeof (struct mtop)))
4105                                 return -EFAULT;
4106                         return (idetape_mtioctop(drive,mtop.mt_op,mtop.mt_count));
4107                 case MTIOCGET:
4108                         memset(&mtget, 0, sizeof (struct mtget));
4109                         mtget.mt_type = MT_ISSCSI2;
4110                         mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
4111                         mtget.mt_dsreg = ((tape->tape_block_size * tape->user_bs_factor) << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
4112                         if (tape->drv_write_prot) {
4113                                 mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
4114                         }
4115                         if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
4116                                 return -EFAULT;
4117                         return 0;
4118                 case MTIOCPOS:
4119                         mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
4120                         if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
4121                                 return -EFAULT;
4122                         return 0;
4123                 default:
4124                         if (tape->chrdev_direction == idetape_direction_read)
4125                                 idetape_discard_read_pipeline(drive, 1);
4126                         return idetape_blkdev_ioctl(drive, cmd, arg);
4127         }
4128 }
4129
4130 static void idetape_get_blocksize_from_block_descriptor(ide_drive_t *drive);
4131
4132 /*
4133  *      Our character device open function.
4134  */
4135 static int idetape_chrdev_open (struct inode *inode, struct file *filp)
4136 {
4137         unsigned int minor = iminor(inode), i = minor & ~0xc0;
4138         ide_drive_t *drive;
4139         idetape_tape_t *tape;
4140         idetape_pc_t pc;
4141         int retval;
4142
4143         /*
4144          * We really want to do nonseekable_open(inode, filp); here, but some
4145          * versions of tar incorrectly call lseek on tapes and bail out if that
4146          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
4147          */
4148         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
4149
4150 #if IDETAPE_DEBUG_LOG
4151         printk(KERN_INFO "ide-tape: Reached idetape_chrdev_open\n");
4152 #endif /* IDETAPE_DEBUG_LOG */
4153         
4154         if (i >= MAX_HWIFS * MAX_DRIVES)
4155                 return -ENXIO;
4156
4157         if (!(tape = ide_tape_chrdev_get(i)))
4158                 return -ENXIO;
4159
4160         drive = tape->drive;
4161
4162         filp->private_data = tape;
4163
4164         if (test_and_set_bit(IDETAPE_BUSY, &tape->flags)) {
4165                 retval = -EBUSY;
4166                 goto out_put_tape;
4167         }
4168
4169         retval = idetape_wait_ready(drive, 60 * HZ);
4170         if (retval) {
4171                 clear_bit(IDETAPE_BUSY, &tape->flags);
4172                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
4173                 goto out_put_tape;
4174         }
4175
4176         idetape_read_position(drive);
4177         if (!test_bit(IDETAPE_ADDRESS_VALID, &tape->flags))
4178                 (void)idetape_rewind_tape(drive);
4179
4180         if (tape->chrdev_direction != idetape_direction_read)
4181                 clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
4182
4183         /* Read block size and write protect status from drive. */
4184         idetape_get_blocksize_from_block_descriptor(drive);
4185
4186         /* Set write protect flag if device is opened as read-only. */
4187         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
4188                 tape->write_prot = 1;
4189         else
4190                 tape->write_prot = tape->drv_write_prot;
4191
4192         /* Make sure drive isn't write protected if user wants to write. */
4193         if (tape->write_prot) {
4194                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
4195                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
4196                         clear_bit(IDETAPE_BUSY, &tape->flags);
4197                         retval = -EROFS;
4198                         goto out_put_tape;
4199                 }
4200         }
4201
4202         /*
4203          * Lock the tape drive door so user can't eject.
4204          */
4205         if (tape->chrdev_direction == idetape_direction_none) {
4206                 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
4207                         if (!idetape_queue_pc_tail(drive, &pc)) {
4208                                 if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
4209                                         tape->door_locked = DOOR_LOCKED;
4210                         }
4211                 }
4212         }
4213         idetape_restart_speed_control(drive);
4214         tape->restart_speed_control_req = 0;
4215         return 0;
4216
4217 out_put_tape:
4218         ide_tape_put(tape);
4219         return retval;
4220 }
4221
4222 static void idetape_write_release (ide_drive_t *drive, unsigned int minor)
4223 {
4224         idetape_tape_t *tape = drive->driver_data;
4225
4226         idetape_empty_write_pipeline(drive);
4227         tape->merge_stage = __idetape_kmalloc_stage(tape, 1, 0);
4228         if (tape->merge_stage != NULL) {
4229                 idetape_pad_zeros(drive, tape->tape_block_size * (tape->user_bs_factor - 1));
4230                 __idetape_kfree_stage(tape->merge_stage);
4231                 tape->merge_stage = NULL;
4232         }
4233         idetape_write_filemark(drive);
4234         idetape_flush_tape_buffers(drive);
4235         idetape_flush_tape_buffers(drive);
4236 }
4237
4238 /*
4239  *      Our character device release function.
4240  */
4241 static int idetape_chrdev_release (struct inode *inode, struct file *filp)
4242 {
4243         struct ide_tape_obj *tape = ide_tape_f(filp);
4244         ide_drive_t *drive = tape->drive;
4245         idetape_pc_t pc;
4246         unsigned int minor = iminor(inode);
4247
4248         lock_kernel();
4249         tape = drive->driver_data;
4250 #if IDETAPE_DEBUG_LOG
4251         if (tape->debug_level >= 3)
4252                 printk(KERN_INFO "ide-tape: Reached idetape_chrdev_release\n");
4253 #endif /* IDETAPE_DEBUG_LOG */
4254
4255         if (tape->chrdev_direction == idetape_direction_write)
4256                 idetape_write_release(drive, minor);
4257         if (tape->chrdev_direction == idetape_direction_read) {
4258                 if (minor < 128)
4259                         idetape_discard_read_pipeline(drive, 1);
4260                 else
4261                         idetape_wait_for_pipeline(drive);
4262         }
4263         if (tape->cache_stage != NULL) {
4264                 __idetape_kfree_stage(tape->cache_stage);
4265                 tape->cache_stage = NULL;
4266         }
4267         if (minor < 128 && test_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags))
4268                 (void) idetape_rewind_tape(drive);
4269         if (tape->chrdev_direction == idetape_direction_none) {
4270                 if (tape->door_locked == DOOR_LOCKED) {
4271                         if (idetape_create_prevent_cmd(drive, &pc, 0)) {
4272                                 if (!idetape_queue_pc_tail(drive, &pc))
4273                                         tape->door_locked = DOOR_UNLOCKED;
4274                         }
4275                 }
4276         }
4277         clear_bit(IDETAPE_BUSY, &tape->flags);
4278         ide_tape_put(tape);
4279         unlock_kernel();
4280         return 0;
4281 }
4282
4283 /*
4284  *      idetape_identify_device is called to check the contents of the
4285  *      ATAPI IDENTIFY command results. We return:
4286  *
4287  *      1       If the tape can be supported by us, based on the information
4288  *              we have so far.
4289  *
4290  *      0       If this tape driver is not currently supported by us.
4291  */
4292 static int idetape_identify_device (ide_drive_t *drive)
4293 {
4294         struct idetape_id_gcw gcw;
4295         struct hd_driveid *id = drive->id;
4296 #if IDETAPE_DEBUG_INFO
4297         unsigned short mask,i;
4298 #endif /* IDETAPE_DEBUG_INFO */
4299
4300         if (drive->id_read == 0)
4301                 return 1;
4302
4303         *((unsigned short *) &gcw) = id->config;
4304
4305 #if IDETAPE_DEBUG_INFO
4306         printk(KERN_INFO "ide-tape: Dumping ATAPI Identify Device tape parameters\n");
4307         printk(KERN_INFO "ide-tape: Protocol Type: ");
4308         switch (gcw.protocol) {
4309                 case 0: case 1: printk("ATA\n");break;
4310                 case 2: printk("ATAPI\n");break;
4311                 case 3: printk("Reserved (Unknown to ide-tape)\n");break;
4312         }
4313         printk(KERN_INFO "ide-tape: Device Type: %x - ",gcw.device_type);       
4314         switch (gcw.device_type) {
4315                 case 0: printk("Direct-access Device\n");break;
4316                 case 1: printk("Streaming Tape Device\n");break;
4317                 case 2: case 3: case 4: printk("Reserved\n");break;
4318                 case 5: printk("CD-ROM Device\n");break;
4319                 case 6: printk("Reserved\n");
4320                 case 7: printk("Optical memory Device\n");break;
4321                 case 0x1f: printk("Unknown or no Device type\n");break;
4322                 default: printk("Reserved\n");
4323         }
4324         printk(KERN_INFO "ide-tape: Removable: %s",gcw.removable ? "Yes\n":"No\n");     
4325         printk(KERN_INFO "ide-tape: Command Packet DRQ Type: ");
4326         switch (gcw.drq_type) {
4327                 case 0: printk("Microprocessor DRQ\n");break;
4328                 case 1: printk("Interrupt DRQ\n");break;
4329                 case 2: printk("Accelerated DRQ\n");break;
4330                 case 3: printk("Reserved\n");break;
4331         }
4332         printk(KERN_INFO "ide-tape: Command Packet Size: ");
4333         switch (gcw.packet_size) {
4334                 case 0: printk("12 bytes\n");break;
4335                 case 1: printk("16 bytes\n");break;
4336                 default: printk("Reserved\n");break;
4337         }
4338         printk(KERN_INFO "ide-tape: Model: %.40s\n",id->model);
4339         printk(KERN_INFO "ide-tape: Firmware Revision: %.8s\n",id->fw_rev);
4340         printk(KERN_INFO "ide-tape: Serial Number: %.20s\n",id->serial_no);
4341         printk(KERN_INFO "ide-tape: Write buffer size: %d bytes\n",id->buf_size*512);
4342         printk(KERN_INFO "ide-tape: DMA: %s",id->capability & 0x01 ? "Yes\n":"No\n");
4343         printk(KERN_INFO "ide-tape: LBA: %s",id->capability & 0x02 ? "Yes\n":"No\n");
4344         printk(KERN_INFO "ide-tape: IORDY can be disabled: %s",id->capability & 0x04 ? "Yes\n":"No\n");
4345         printk(KERN_INFO "ide-tape: IORDY supported: %s",id->capability & 0x08 ? "Yes\n":"Unknown\n");
4346         printk(KERN_INFO "ide-tape: ATAPI overlap supported: %s",id->capability & 0x20 ? "Yes\n":"No\n");
4347         printk(KERN_INFO "ide-tape: PIO Cycle Timing Category: %d\n",id->tPIO);
4348         printk(KERN_INFO "ide-tape: DMA Cycle Timing Category: %d\n",id->tDMA);
4349         printk(KERN_INFO "ide-tape: Single Word DMA supported modes: ");
4350         for (i=0,mask=1;i<8;i++,mask=mask << 1) {
4351                 if (id->dma_1word & mask)
4352                         printk("%d ",i);
4353                 if (id->dma_1word & (mask << 8))
4354                         printk("(active) ");
4355         }
4356         printk("\n");
4357         printk(KERN_INFO "ide-tape: Multi Word DMA supported modes: ");
4358         for (i=0,mask=1;i<8;i++,mask=mask << 1) {
4359                 if (id->dma_mword & mask)
4360                         printk("%d ",i);
4361                 if (id->dma_mword & (mask << 8))
4362                         printk("(active) ");
4363         }
4364         printk("\n");
4365         if (id->field_valid & 0x0002) {
4366                 printk(KERN_INFO "ide-tape: Enhanced PIO Modes: %s\n",
4367                         id->eide_pio_modes & 1 ? "Mode 3":"None");
4368                 printk(KERN_INFO "ide-tape: Minimum Multi-word DMA cycle per word: ");
4369                 if (id->eide_dma_min == 0)
4370                         printk("Not supported\n");
4371                 else
4372                         printk("%d ns\n",id->eide_dma_min);
4373
4374                 printk(KERN_INFO "ide-tape: Manufacturer\'s Recommended Multi-word cycle: ");
4375                 if (id->eide_dma_time == 0)
4376                         printk("Not supported\n");
4377                 else
4378                         printk("%d ns\n",id->eide_dma_time);
4379
4380                 printk(KERN_INFO "ide-tape: Minimum PIO cycle without IORDY: ");
4381                 if (id->eide_pio == 0)
4382                         printk("Not supported\n");
4383                 else
4384                         printk("%d ns\n",id->eide_pio);
4385
4386                 printk(KERN_INFO "ide-tape: Minimum PIO cycle with IORDY: ");
4387                 if (id->eide_pio_iordy == 0)
4388                         printk("Not supported\n");
4389                 else
4390                         printk("%d ns\n",id->eide_pio_iordy);
4391                 
4392         } else
4393                 printk(KERN_INFO "ide-tape: According to the device, fields 64-70 are not valid.\n");
4394 #endif /* IDETAPE_DEBUG_INFO */
4395
4396         /* Check that we can support this device */
4397
4398         if (gcw.protocol !=2 )
4399                 printk(KERN_ERR "ide-tape: Protocol is not ATAPI\n");
4400         else if (gcw.device_type != 1)
4401                 printk(KERN_ERR "ide-tape: Device type is not set to tape\n");
4402         else if (!gcw.removable)
4403                 printk(KERN_ERR "ide-tape: The removable flag is not set\n");
4404         else if (gcw.packet_size != 0) {
4405                 printk(KERN_ERR "ide-tape: Packet size is not 12 bytes long\n");
4406                 if (gcw.packet_size == 1)
4407                         printk(KERN_ERR "ide-tape: Sorry, padding to 16 bytes is still not supported\n");
4408         } else
4409                 return 1;
4410         return 0;
4411 }
4412
4413 /*
4414  * Use INQUIRY to get the firmware revision
4415  */
4416 static void idetape_get_inquiry_results (ide_drive_t *drive)
4417 {
4418         char *r;
4419         idetape_tape_t *tape = drive->driver_data;
4420         idetape_pc_t pc;
4421         idetape_inquiry_result_t *inquiry;
4422         
4423         idetape_create_inquiry_cmd(&pc);
4424         if (idetape_queue_pc_tail(drive, &pc)) {
4425                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n", tape->name);
4426                 return;
4427         }
4428         inquiry = (idetape_inquiry_result_t *) pc.buffer;
4429         memcpy(tape->vendor_id, inquiry->vendor_id, 8);
4430         memcpy(tape->product_id, inquiry->product_id, 16);
4431         memcpy(tape->firmware_revision, inquiry->revision_level, 4);
4432         ide_fixstring(tape->vendor_id, 10, 0);
4433         ide_fixstring(tape->product_id, 18, 0);
4434         ide_fixstring(tape->firmware_revision, 6, 0);
4435         r = tape->firmware_revision;
4436         if (*(r + 1) == '.')
4437                 tape->firmware_revision_num = (*r - '0') * 100 + (*(r + 2) - '0') * 10 + *(r + 3) - '0';
4438         printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n", drive->name, tape->name, tape->vendor_id, tape->product_id, tape->firmware_revision);
4439 }
4440
4441 /*
4442  *      idetape_get_mode_sense_results asks the tape about its various
4443  *      parameters. In particular, we will adjust our data transfer buffer
4444  *      size to the recommended value as returned by the tape.
4445  */
4446 static void idetape_get_mode_sense_results (ide_drive_t *drive)
4447 {
4448         idetape_tape_t *tape = drive->driver_data;
4449         idetape_pc_t pc;
4450         idetape_mode_parameter_header_t *header;
4451         idetape_capabilities_page_t *capabilities;
4452         
4453         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
4454         if (idetape_queue_pc_tail(drive, &pc)) {
4455                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming some default values\n");
4456                 tape->tape_block_size = 512;
4457                 tape->capabilities.ctl = 52;
4458                 tape->capabilities.speed = 450;
4459                 tape->capabilities.buffer_size = 6 * 52;
4460                 return;
4461         }
4462         header = (idetape_mode_parameter_header_t *) pc.buffer;
4463         capabilities = (idetape_capabilities_page_t *) (pc.buffer + sizeof(idetape_mode_parameter_header_t) + header->bdl);
4464
4465         capabilities->max_speed = ntohs(capabilities->max_speed);
4466         capabilities->ctl = ntohs(capabilities->ctl);
4467         capabilities->speed = ntohs(capabilities->speed);
4468         capabilities->buffer_size = ntohs(capabilities->buffer_size);
4469
4470         if (!capabilities->speed) {
4471                 printk(KERN_INFO "ide-tape: %s: overriding capabilities->speed (assuming 650KB/sec)\n", drive->name);
4472                 capabilities->speed = 650;
4473         }
4474         if (!capabilities->max_speed) {
4475                 printk(KERN_INFO "ide-tape: %s: overriding capabilities->max_speed (assuming 650KB/sec)\n", drive->name);
4476                 capabilities->max_speed = 650;
4477         }
4478
4479         tape->capabilities = *capabilities;             /* Save us a copy */
4480         if (capabilities->blk512)
4481                 tape->tape_block_size = 512;
4482         else if (capabilities->blk1024)
4483                 tape->tape_block_size = 1024;
4484
4485 #if IDETAPE_DEBUG_INFO
4486         printk(KERN_INFO "ide-tape: Dumping the results of the MODE SENSE packet command\n");
4487         printk(KERN_INFO "ide-tape: Mode Parameter Header:\n");
4488         printk(KERN_INFO "ide-tape: Mode Data Length - %d\n",header->mode_data_length);
4489         printk(KERN_INFO "ide-tape: Medium Type - %d\n",header->medium_type);
4490         printk(KERN_INFO "ide-tape: Device Specific Parameter - %d\n",header->dsp);
4491         printk(KERN_INFO "ide-tape: Block Descriptor Length - %d\n",header->bdl);
4492         
4493         printk(KERN_INFO "ide-tape: Capabilities and Mechanical Status Page:\n");
4494         printk(KERN_INFO "ide-tape: Page code - %d\n",capabilities->page_code);
4495         printk(KERN_INFO "ide-tape: Page length - %d\n",capabilities->page_length);
4496         printk(KERN_INFO "ide-tape: Read only - %s\n",capabilities->ro ? "Yes":"No");
4497         printk(KERN_INFO "ide-tape: Supports reverse space - %s\n",capabilities->sprev ? "Yes":"No");
4498         printk(KERN_INFO "ide-tape: Supports erase initiated formatting - %s\n",capabilities->efmt ? "Yes":"No");
4499         printk(KERN_INFO "ide-tape: Supports QFA two Partition format - %s\n",capabilities->qfa ? "Yes":"No");
4500         printk(KERN_INFO "ide-tape: Supports locking the medium - %s\n",capabilities->lock ? "Yes":"No");
4501         printk(KERN_INFO "ide-tape: The volume is currently locked - %s\n",capabilities->locked ? "Yes":"No");
4502         printk(KERN_INFO "ide-tape: The device defaults in the prevent state - %s\n",capabilities->prevent ? "Yes":"No");
4503         printk(KERN_INFO "ide-tape: Supports ejecting the medium - %s\n",capabilities->eject ? "Yes":"No");
4504         printk(KERN_INFO "ide-tape: Supports error correction - %s\n",capabilities->ecc ? "Yes":"No");
4505         printk(KERN_INFO "ide-tape: Supports data compression - %s\n",capabilities->cmprs ? "Yes":"No");
4506         printk(KERN_INFO "ide-tape: Supports 512 bytes block size - %s\n",capabilities->blk512 ? "Yes":"No");
4507         printk(KERN_INFO "ide-tape: Supports 1024 bytes block size - %s\n",capabilities->blk1024 ? "Yes":"No");
4508         printk(KERN_INFO "ide-tape: Supports 32768 bytes block size / Restricted byte count for PIO transfers - %s\n",capabilities->blk32768 ? "Yes":"No");
4509         printk(KERN_INFO "ide-tape: Maximum supported speed in KBps - %d\n",capabilities->max_speed);
4510         printk(KERN_INFO "ide-tape: Continuous transfer limits in blocks - %d\n",capabilities->ctl);
4511         printk(KERN_INFO "ide-tape: Current speed in KBps - %d\n",capabilities->speed); 
4512         printk(KERN_INFO "ide-tape: Buffer size - %d\n",capabilities->buffer_size*512);
4513 #endif /* IDETAPE_DEBUG_INFO */
4514 }
4515
4516 /*
4517  *      ide_get_blocksize_from_block_descriptor does a mode sense page 0 with block descriptor
4518  *      and if it succeeds sets the tape block size with the reported value
4519  */
4520 static void idetape_get_blocksize_from_block_descriptor(ide_drive_t *drive)
4521 {
4522
4523         idetape_tape_t *tape = drive->driver_data;
4524         idetape_pc_t pc;
4525         idetape_mode_parameter_header_t *header;
4526         idetape_parameter_block_descriptor_t *block_descrp;
4527         
4528         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
4529         if (idetape_queue_pc_tail(drive, &pc)) {
4530                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
4531                 if (tape->tape_block_size == 0) {
4532                         printk(KERN_WARNING "ide-tape: Cannot deal with zero block size, assume 32k\n");
4533                         tape->tape_block_size =  32768;
4534                 }
4535                 return;
4536         }
4537         header = (idetape_mode_parameter_header_t *) pc.buffer;
4538         block_descrp = (idetape_parameter_block_descriptor_t *) (pc.buffer + sizeof(idetape_mode_parameter_header_t));
4539         tape->tape_block_size =( block_descrp->length[0]<<16) + (block_descrp->length[1]<<8) + block_descrp->length[2];
4540         tape->drv_write_prot = (header->dsp & 0x80) >> 7;
4541
4542 #if IDETAPE_DEBUG_INFO
4543         printk(KERN_INFO "ide-tape: Adjusted block size - %d\n", tape->tape_block_size);
4544 #endif /* IDETAPE_DEBUG_INFO */
4545 }
4546 static void idetape_add_settings (ide_drive_t *drive)
4547 {
4548         idetape_tape_t *tape = drive->driver_data;
4549
4550 /*
4551  *                      drive   setting name    read/write      ioctl   ioctl           data type       min                     max                     mul_factor                      div_factor                      data pointer                            set function
4552  */
4553         ide_add_setting(drive,  "buffer",       SETTING_READ,   -1,     -1,             TYPE_SHORT,     0,                      0xffff,                 1,                              2,                              &tape->capabilities.buffer_size,        NULL);
4554         ide_add_setting(drive,  "pipeline_min", SETTING_RW,     -1,     -1,             TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,                              &tape->min_pipeline,                    NULL);
4555         ide_add_setting(drive,  "pipeline",     SETTING_RW,     -1,     -1,             TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,                              &tape->max_stages,                      NULL);
4556         ide_add_setting(drive,  "pipeline_max", SETTING_RW,     -1,     -1,             TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,                              &tape->max_pipeline,                    NULL);
4557         ide_add_setting(drive,  "pipeline_used",SETTING_READ,   -1,     -1,             TYPE_INT,       0,                      0xffff,                 tape->stage_size / 1024,        1,                              &tape->nr_stages,                       NULL);
4558         ide_add_setting(drive,  "pipeline_pending",SETTING_READ,-1,     -1,             TYPE_INT,       0,                      0xffff,                 tape->stage_size / 1024,        1,                              &tape->nr_pending_stages,               NULL);
4559         ide_add_setting(drive,  "speed",        SETTING_READ,   -1,     -1,             TYPE_SHORT,     0,                      0xffff,                 1,                              1,                              &tape->capabilities.speed,              NULL);
4560         ide_add_setting(drive,  "stage",        SETTING_READ,   -1,     -1,             TYPE_INT,       0,                      0xffff,                 1,                              1024,                           &tape->stage_size,                      NULL);
4561         ide_add_setting(drive,  "tdsc",         SETTING_RW,     -1,     -1,             TYPE_INT,       IDETAPE_DSC_RW_MIN,     IDETAPE_DSC_RW_MAX,     1000,                           HZ,                             &tape->best_dsc_rw_frequency,           NULL);
4562         ide_add_setting(drive,  "dsc_overlap",  SETTING_RW,     -1,     -1,             TYPE_BYTE,      0,                      1,                      1,                              1,                              &drive->dsc_overlap,                    NULL);
4563         ide_add_setting(drive,  "pipeline_head_speed_c",SETTING_READ,   -1,     -1,     TYPE_INT,       0,                      0xffff,                 1,                              1,                              &tape->controlled_pipeline_head_speed,  NULL);
4564         ide_add_setting(drive,  "pipeline_head_speed_u",SETTING_READ,   -1,     -1,     TYPE_INT,       0,                      0xffff,                 1,                              1,                              &tape->uncontrolled_pipeline_head_speed,        NULL);
4565         ide_add_setting(drive,  "avg_speed",    SETTING_READ,   -1,     -1,             TYPE_INT,       0,                      0xffff,                 1,                              1,                              &tape->avg_speed,               NULL);
4566         ide_add_setting(drive,  "debug_level",SETTING_RW,       -1,     -1,             TYPE_INT,       0,                      0xffff,                 1,                              1,                              &tape->debug_level,             NULL);
4567 }
4568
4569 /*
4570  *      ide_setup is called to:
4571  *
4572  *              1.      Initialize our various state variables.
4573  *              2.      Ask the tape for its capabilities.
4574  *              3.      Allocate a buffer which will be used for data
4575  *                      transfer. The buffer size is chosen based on
4576  *                      the recommendation which we received in step (2).
4577  *
4578  *      Note that at this point ide.c already assigned us an irq, so that
4579  *      we can queue requests here and wait for their completion.
4580  */
4581 static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
4582 {
4583         unsigned long t1, tmid, tn, t;
4584         int speed;
4585         struct idetape_id_gcw gcw;
4586         int stage_size;
4587         struct sysinfo si;
4588
4589         spin_lock_init(&tape->spinlock);
4590         drive->dsc_overlap = 1;
4591 #ifdef CONFIG_BLK_DEV_IDEPCI
4592         if (HWIF(drive)->pci_dev != NULL) {
4593                 /*
4594                  * These two ide-pci host adapters appear to need DSC overlap disabled.
4595                  * This probably needs further analysis.
4596                  */
4597                 if ((HWIF(drive)->pci_dev->device == PCI_DEVICE_ID_ARTOP_ATP850UF) ||
4598                     (HWIF(drive)->pci_dev->device == PCI_DEVICE_ID_TTI_HPT343)) {
4599                         printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n", tape->name);
4600                         drive->dsc_overlap = 0;
4601                 }
4602         }
4603 #endif /* CONFIG_BLK_DEV_IDEPCI */
4604         /* Seagate Travan drives do not support DSC overlap. */
4605         if (strstr(drive->id->model, "Seagate STT3401"))
4606                 drive->dsc_overlap = 0;
4607         tape->minor = minor;
4608         tape->name[0] = 'h';
4609         tape->name[1] = 't';
4610         tape->name[2] = '0' + minor;
4611         tape->chrdev_direction = idetape_direction_none;
4612         tape->pc = tape->pc_stack;
4613         tape->max_insert_speed = 10000;
4614         tape->speed_control = 1;
4615         *((unsigned short *) &gcw) = drive->id->config;
4616         if (gcw.drq_type == 1)
4617                 set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags);
4618
4619         tape->min_pipeline = tape->max_pipeline = tape->max_stages = 10;
4620         
4621         idetape_get_inquiry_results(drive);
4622         idetape_get_mode_sense_results(drive);
4623         idetape_get_blocksize_from_block_descriptor(drive);
4624         tape->user_bs_factor = 1;
4625         tape->stage_size = tape->capabilities.ctl * tape->tape_block_size;
4626         while (tape->stage_size > 0xffff) {
4627                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
4628                 tape->capabilities.ctl /= 2;
4629                 tape->stage_size = tape->capabilities.ctl * tape->tape_block_size;
4630         }
4631         stage_size = tape->stage_size;
4632         tape->pages_per_stage = stage_size / PAGE_SIZE;
4633         if (stage_size % PAGE_SIZE) {
4634                 tape->pages_per_stage++;
4635                 tape->excess_bh_size = PAGE_SIZE - stage_size % PAGE_SIZE;
4636         }
4637
4638         /*
4639          *      Select the "best" DSC read/write polling frequency
4640          *      and pipeline size.
4641          */
4642         speed = max(tape->capabilities.speed, tape->capabilities.max_speed);
4643
4644         tape->max_stages = speed * 1000 * 10 / tape->stage_size;
4645
4646         /*
4647          *      Limit memory use for pipeline to 10% of physical memory
4648          */
4649         si_meminfo(&si);
4650         if (tape->max_stages * tape->stage_size > si.totalram * si.mem_unit / 10)
4651                 tape->max_stages = si.totalram * si.mem_unit / (10 * tape->stage_size);
4652         tape->max_stages   = min(tape->max_stages, IDETAPE_MAX_PIPELINE_STAGES);
4653         tape->min_pipeline = min(tape->max_stages, IDETAPE_MIN_PIPELINE_STAGES);
4654         tape->max_pipeline = min(tape->max_stages * 2, IDETAPE_MAX_PIPELINE_STAGES);
4655         if (tape->max_stages == 0)
4656                 tape->max_stages = tape->min_pipeline = tape->max_pipeline = 1;
4657
4658         t1 = (tape->stage_size * HZ) / (speed * 1000);
4659         tmid = (tape->capabilities.buffer_size * 32 * HZ) / (speed * 125);
4660         tn = (IDETAPE_FIFO_THRESHOLD * tape->stage_size * HZ) / (speed * 1000);
4661
4662         if (tape->max_stages)
4663                 t = tn;
4664         else
4665                 t = t1;
4666
4667         /*
4668          *      Ensure that the number we got makes sense; limit
4669          *      it within IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
4670          */
4671         tape->best_dsc_rw_frequency = max_t(unsigned long, min_t(unsigned long, t, IDETAPE_DSC_RW_MAX), IDETAPE_DSC_RW_MIN);
4672         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
4673                 "%dkB pipeline, %lums tDSC%s\n",
4674                 drive->name, tape->name, tape->capabilities.speed,
4675                 (tape->capabilities.buffer_size * 512) / tape->stage_size,
4676                 tape->stage_size / 1024,
4677                 tape->max_stages * tape->stage_size / 1024,
4678                 tape->best_dsc_rw_frequency * 1000 / HZ,
4679                 drive->using_dma ? ", DMA":"");
4680
4681         idetape_add_settings(drive);
4682 }
4683
4684 static int ide_tape_remove(struct device *dev)
4685 {
4686         ide_drive_t *drive = to_ide_device(dev);
4687         idetape_tape_t *tape = drive->driver_data;
4688
4689         ide_unregister_subdriver(drive, tape->driver);
4690
4691         ide_unregister_region(tape->disk);
4692
4693         ide_tape_put(tape);
4694
4695         return 0;
4696 }
4697
4698 static void ide_tape_release(struct kref *kref)
4699 {
4700         struct ide_tape_obj *tape = to_ide_tape(kref);
4701         ide_drive_t *drive = tape->drive;
4702         struct gendisk *g = tape->disk;
4703
4704         BUG_ON(tape->first_stage != NULL || tape->merge_stage_size);
4705
4706         drive->dsc_overlap = 0;
4707         drive->driver_data = NULL;
4708         devfs_remove("%s/mt", drive->devfs_name);
4709         devfs_remove("%s/mtn", drive->devfs_name);
4710         devfs_unregister_tape(g->number);
4711         idetape_devs[tape->minor] = NULL;
4712         g->private_data = NULL;
4713         put_disk(g);
4714         kfree(tape);
4715 }
4716
4717 #ifdef CONFIG_PROC_FS
4718
4719 static int proc_idetape_read_name
4720         (char *page, char **start, off_t off, int count, int *eof, void *data)
4721 {
4722         ide_drive_t     *drive = (ide_drive_t *) data;
4723         idetape_tape_t  *tape = drive->driver_data;
4724         char            *out = page;
4725         int             len;
4726
4727         len = sprintf(out, "%s\n", tape->name);
4728         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
4729 }
4730
4731 static ide_proc_entry_t idetape_proc[] = {
4732         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
4733         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
4734         { NULL, 0, NULL, NULL }
4735 };
4736
4737 #else
4738
4739 #define idetape_proc    NULL
4740
4741 #endif
4742
4743 static int ide_tape_probe(struct device *);
4744
4745 static ide_driver_t idetape_driver = {
4746         .owner                  = THIS_MODULE,
4747         .gen_driver = {
4748                 .name           = "ide-tape",
4749                 .bus            = &ide_bus_type,
4750                 .probe          = ide_tape_probe,
4751                 .remove         = ide_tape_remove,
4752         },
4753         .version                = IDETAPE_VERSION,
4754         .media                  = ide_tape,
4755         .supports_dsc_overlap   = 1,
4756         .do_request             = idetape_do_request,
4757         .end_request            = idetape_end_request,
4758         .error                  = __ide_error,
4759         .abort                  = __ide_abort,
4760         .proc                   = idetape_proc,
4761 };
4762
4763 /*
4764  *      Our character device supporting functions, passed to register_chrdev.
4765  */
4766 static struct file_operations idetape_fops = {
4767         .owner          = THIS_MODULE,
4768         .read           = idetape_chrdev_read,
4769         .write          = idetape_chrdev_write,
4770         .ioctl          = idetape_chrdev_ioctl,
4771         .open           = idetape_chrdev_open,
4772         .release        = idetape_chrdev_release,
4773 };
4774
4775 static int idetape_open(struct inode *inode, struct file *filp)
4776 {
4777         struct gendisk *disk = inode->i_bdev->bd_disk;
4778         struct ide_tape_obj *tape;
4779         ide_drive_t *drive;
4780
4781         if (!(tape = ide_tape_get(disk)))
4782                 return -ENXIO;
4783
4784         drive = tape->drive;
4785
4786         drive->usage++;
4787
4788         return 0;
4789 }
4790
4791 static int idetape_release(struct inode *inode, struct file *filp)
4792 {
4793         struct gendisk *disk = inode->i_bdev->bd_disk;
4794         struct ide_tape_obj *tape = ide_tape_g(disk);
4795         ide_drive_t *drive = tape->drive;
4796
4797         drive->usage--;
4798
4799         ide_tape_put(tape);
4800
4801         return 0;
4802 }
4803
4804 static int idetape_ioctl(struct inode *inode, struct file *file,
4805                         unsigned int cmd, unsigned long arg)
4806 {
4807         struct block_device *bdev = inode->i_bdev;
4808         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
4809         ide_drive_t *drive = tape->drive;
4810         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
4811         if (err == -EINVAL)
4812                 err = idetape_blkdev_ioctl(drive, cmd, arg);
4813         return err;
4814 }
4815
4816 static struct block_device_operations idetape_block_ops = {
4817         .owner          = THIS_MODULE,
4818         .open           = idetape_open,
4819         .release        = idetape_release,
4820         .ioctl          = idetape_ioctl,
4821 };
4822
4823 static int ide_tape_probe(struct device *dev)
4824 {
4825         ide_drive_t *drive = to_ide_device(dev);
4826         idetape_tape_t *tape;
4827         struct gendisk *g;
4828         int minor;
4829
4830         if (!strstr("ide-tape", drive->driver_req))
4831                 goto failed;
4832         if (!drive->present)
4833                 goto failed;
4834         if (drive->media != ide_tape)
4835                 goto failed;
4836         if (!idetape_identify_device (drive)) {
4837                 printk(KERN_ERR "ide-tape: %s: not supported by this version of ide-tape\n", drive->name);
4838                 goto failed;
4839         }
4840         if (drive->scsi) {
4841                 printk("ide-tape: passing drive %s to ide-scsi emulation.\n", drive->name);
4842                 goto failed;
4843         }
4844         if (strstr(drive->id->model, "OnStream DI-")) {
4845                 printk(KERN_WARNING "ide-tape: Use drive %s with ide-scsi emulation and osst.\n", drive->name);
4846                 printk(KERN_WARNING "ide-tape: OnStream support will be removed soon from ide-tape!\n");
4847         }
4848         tape = (idetape_tape_t *) kmalloc (sizeof (idetape_tape_t), GFP_KERNEL);
4849         if (tape == NULL) {
4850                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape structure\n", drive->name);
4851                 goto failed;
4852         }
4853
4854         g = alloc_disk(1 << PARTN_BITS);
4855         if (!g)
4856                 goto out_free_tape;
4857
4858         ide_init_disk(g, drive);
4859
4860         ide_register_subdriver(drive, &idetape_driver);
4861
4862         memset(tape, 0, sizeof(*tape));
4863
4864         kref_init(&tape->kref);
4865
4866         tape->drive = drive;
4867         tape->driver = &idetape_driver;
4868         tape->disk = g;
4869
4870         g->private_data = &tape->driver;
4871
4872         drive->driver_data = tape;
4873
4874         down(&idetape_ref_sem);
4875         for (minor = 0; idetape_devs[minor]; minor++)
4876                 ;
4877         idetape_devs[minor] = tape;
4878         up(&idetape_ref_sem);
4879
4880         idetape_setup(drive, tape, minor);
4881
4882         devfs_mk_cdev(MKDEV(HWIF(drive)->major, minor),
4883                         S_IFCHR | S_IRUGO | S_IWUGO,
4884                         "%s/mt", drive->devfs_name);
4885         devfs_mk_cdev(MKDEV(HWIF(drive)->major, minor + 128),
4886                         S_IFCHR | S_IRUGO | S_IWUGO,
4887                         "%s/mtn", drive->devfs_name);
4888
4889         g->number = devfs_register_tape(drive->devfs_name);
4890         g->fops = &idetape_block_ops;
4891         ide_register_region(g);
4892
4893         return 0;
4894
4895 out_free_tape:
4896         kfree(tape);
4897 failed:
4898         return -ENODEV;
4899 }
4900
4901 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
4902 MODULE_LICENSE("GPL");
4903
4904 static void __exit idetape_exit (void)
4905 {
4906         driver_unregister(&idetape_driver.gen_driver);
4907         unregister_chrdev(IDETAPE_MAJOR, "ht");
4908 }
4909
4910 /*
4911  *      idetape_init will register the driver for each tape.
4912  */
4913 static int idetape_init (void)
4914 {
4915         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
4916                 printk(KERN_ERR "ide-tape: Failed to register character device interface\n");
4917                 return -EBUSY;
4918         }
4919         return driver_register(&idetape_driver.gen_driver);
4920 }
4921
4922 module_init(idetape_init);
4923 module_exit(idetape_exit);
4924 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);