ide: remove SECTOR_WORDS define
[linux-2.6] / drivers / ide / ide-io.c
1 /*
2  *      IDE I/O functions
3  *
4  *      Basic PIO and command management functionality.
5  *
6  * This code was split off from ide.c. See ide.c for history and original
7  * copyrights.
8  *
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU General Public License as published by the
11  * Free Software Foundation; either version 2, or (at your option) any
12  * later version.
13  *
14  * This program is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  * General Public License for more details.
18  *
19  * For the avoidance of doubt the "preferred form" of this code is one which
20  * is in an open non patent encumbered format. Where cryptographic key signing
21  * forms part of the process of creating an executable the information
22  * including keys needed to generate an equivalently functional executable
23  * are deemed to be part of the source code.
24  */
25  
26  
27 #include <linux/module.h>
28 #include <linux/types.h>
29 #include <linux/string.h>
30 #include <linux/kernel.h>
31 #include <linux/timer.h>
32 #include <linux/mm.h>
33 #include <linux/interrupt.h>
34 #include <linux/major.h>
35 #include <linux/errno.h>
36 #include <linux/genhd.h>
37 #include <linux/blkpg.h>
38 #include <linux/slab.h>
39 #include <linux/init.h>
40 #include <linux/pci.h>
41 #include <linux/delay.h>
42 #include <linux/ide.h>
43 #include <linux/hdreg.h>
44 #include <linux/completion.h>
45 #include <linux/reboot.h>
46 #include <linux/cdrom.h>
47 #include <linux/seq_file.h>
48 #include <linux/device.h>
49 #include <linux/kmod.h>
50 #include <linux/scatterlist.h>
51 #include <linux/bitops.h>
52
53 #include <asm/byteorder.h>
54 #include <asm/irq.h>
55 #include <asm/uaccess.h>
56 #include <asm/io.h>
57
58 static int __ide_end_request(ide_drive_t *drive, struct request *rq,
59                              int uptodate, unsigned int nr_bytes, int dequeue)
60 {
61         int ret = 1;
62         int error = 0;
63
64         if (uptodate <= 0)
65                 error = uptodate ? uptodate : -EIO;
66
67         /*
68          * if failfast is set on a request, override number of sectors and
69          * complete the whole request right now
70          */
71         if (blk_noretry_request(rq) && error)
72                 nr_bytes = rq->hard_nr_sectors << 9;
73
74         if (!blk_fs_request(rq) && error && !rq->errors)
75                 rq->errors = -EIO;
76
77         /*
78          * decide whether to reenable DMA -- 3 is a random magic for now,
79          * if we DMA timeout more than 3 times, just stay in PIO
80          */
81         if (drive->state == DMA_PIO_RETRY && drive->retry_pio <= 3) {
82                 drive->state = 0;
83                 ide_dma_on(drive);
84         }
85
86         if (!__blk_end_request(rq, error, nr_bytes)) {
87                 if (dequeue)
88                         HWGROUP(drive)->rq = NULL;
89                 ret = 0;
90         }
91
92         return ret;
93 }
94
95 /**
96  *      ide_end_request         -       complete an IDE I/O
97  *      @drive: IDE device for the I/O
98  *      @uptodate:
99  *      @nr_sectors: number of sectors completed
100  *
101  *      This is our end_request wrapper function. We complete the I/O
102  *      update random number input and dequeue the request, which if
103  *      it was tagged may be out of order.
104  */
105
106 int ide_end_request (ide_drive_t *drive, int uptodate, int nr_sectors)
107 {
108         unsigned int nr_bytes = nr_sectors << 9;
109         struct request *rq;
110         unsigned long flags;
111         int ret = 1;
112
113         /*
114          * room for locking improvements here, the calls below don't
115          * need the queue lock held at all
116          */
117         spin_lock_irqsave(&ide_lock, flags);
118         rq = HWGROUP(drive)->rq;
119
120         if (!nr_bytes) {
121                 if (blk_pc_request(rq))
122                         nr_bytes = rq->data_len;
123                 else
124                         nr_bytes = rq->hard_cur_sectors << 9;
125         }
126
127         ret = __ide_end_request(drive, rq, uptodate, nr_bytes, 1);
128
129         spin_unlock_irqrestore(&ide_lock, flags);
130         return ret;
131 }
132 EXPORT_SYMBOL(ide_end_request);
133
134 /*
135  * Power Management state machine. This one is rather trivial for now,
136  * we should probably add more, like switching back to PIO on suspend
137  * to help some BIOSes, re-do the door locking on resume, etc...
138  */
139
140 enum {
141         ide_pm_flush_cache      = ide_pm_state_start_suspend,
142         idedisk_pm_standby,
143
144         idedisk_pm_restore_pio  = ide_pm_state_start_resume,
145         idedisk_pm_idle,
146         ide_pm_restore_dma,
147 };
148
149 static void ide_complete_power_step(ide_drive_t *drive, struct request *rq, u8 stat, u8 error)
150 {
151         struct request_pm_state *pm = rq->data;
152
153         if (drive->media != ide_disk)
154                 return;
155
156         switch (pm->pm_step) {
157         case ide_pm_flush_cache:        /* Suspend step 1 (flush cache) complete */
158                 if (pm->pm_state == PM_EVENT_FREEZE)
159                         pm->pm_step = ide_pm_state_completed;
160                 else
161                         pm->pm_step = idedisk_pm_standby;
162                 break;
163         case idedisk_pm_standby:        /* Suspend step 2 (standby) complete */
164                 pm->pm_step = ide_pm_state_completed;
165                 break;
166         case idedisk_pm_restore_pio:    /* Resume step 1 complete */
167                 pm->pm_step = idedisk_pm_idle;
168                 break;
169         case idedisk_pm_idle:           /* Resume step 2 (idle) complete */
170                 pm->pm_step = ide_pm_restore_dma;
171                 break;
172         }
173 }
174
175 static ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
176 {
177         struct request_pm_state *pm = rq->data;
178         ide_task_t *args = rq->special;
179
180         memset(args, 0, sizeof(*args));
181
182         switch (pm->pm_step) {
183         case ide_pm_flush_cache:        /* Suspend step 1 (flush cache) */
184                 if (drive->media != ide_disk)
185                         break;
186                 /* Not supported? Switch to next step now. */
187                 if (!drive->wcache || !ide_id_has_flush_cache(drive->id)) {
188                         ide_complete_power_step(drive, rq, 0, 0);
189                         return ide_stopped;
190                 }
191                 if (ide_id_has_flush_cache_ext(drive->id))
192                         args->tf.command = ATA_CMD_FLUSH_EXT;
193                 else
194                         args->tf.command = ATA_CMD_FLUSH;
195                 goto out_do_tf;
196
197         case idedisk_pm_standby:        /* Suspend step 2 (standby) */
198                 args->tf.command = ATA_CMD_STANDBYNOW1;
199                 goto out_do_tf;
200
201         case idedisk_pm_restore_pio:    /* Resume step 1 (restore PIO) */
202                 ide_set_max_pio(drive);
203                 /*
204                  * skip idedisk_pm_idle for ATAPI devices
205                  */
206                 if (drive->media != ide_disk)
207                         pm->pm_step = ide_pm_restore_dma;
208                 else
209                         ide_complete_power_step(drive, rq, 0, 0);
210                 return ide_stopped;
211
212         case idedisk_pm_idle:           /* Resume step 2 (idle) */
213                 args->tf.command = ATA_CMD_IDLEIMMEDIATE;
214                 goto out_do_tf;
215
216         case ide_pm_restore_dma:        /* Resume step 3 (restore DMA) */
217                 /*
218                  * Right now, all we do is call ide_set_dma(drive),
219                  * we could be smarter and check for current xfer_speed
220                  * in struct drive etc...
221                  */
222                 if (drive->hwif->dma_ops == NULL)
223                         break;
224                 /*
225                  * TODO: respect ->using_dma setting
226                  */
227                 ide_set_dma(drive);
228                 break;
229         }
230         pm->pm_step = ide_pm_state_completed;
231         return ide_stopped;
232
233 out_do_tf:
234         args->tf_flags   = IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
235         args->data_phase = TASKFILE_NO_DATA;
236         return do_rw_taskfile(drive, args);
237 }
238
239 /**
240  *      ide_end_dequeued_request        -       complete an IDE I/O
241  *      @drive: IDE device for the I/O
242  *      @uptodate:
243  *      @nr_sectors: number of sectors completed
244  *
245  *      Complete an I/O that is no longer on the request queue. This
246  *      typically occurs when we pull the request and issue a REQUEST_SENSE.
247  *      We must still finish the old request but we must not tamper with the
248  *      queue in the meantime.
249  *
250  *      NOTE: This path does not handle barrier, but barrier is not supported
251  *      on ide-cd anyway.
252  */
253
254 int ide_end_dequeued_request(ide_drive_t *drive, struct request *rq,
255                              int uptodate, int nr_sectors)
256 {
257         unsigned long flags;
258         int ret;
259
260         spin_lock_irqsave(&ide_lock, flags);
261         BUG_ON(!blk_rq_started(rq));
262         ret = __ide_end_request(drive, rq, uptodate, nr_sectors << 9, 0);
263         spin_unlock_irqrestore(&ide_lock, flags);
264
265         return ret;
266 }
267 EXPORT_SYMBOL_GPL(ide_end_dequeued_request);
268
269
270 /**
271  *      ide_complete_pm_request - end the current Power Management request
272  *      @drive: target drive
273  *      @rq: request
274  *
275  *      This function cleans up the current PM request and stops the queue
276  *      if necessary.
277  */
278 static void ide_complete_pm_request (ide_drive_t *drive, struct request *rq)
279 {
280         unsigned long flags;
281
282 #ifdef DEBUG_PM
283         printk("%s: completing PM request, %s\n", drive->name,
284                blk_pm_suspend_request(rq) ? "suspend" : "resume");
285 #endif
286         spin_lock_irqsave(&ide_lock, flags);
287         if (blk_pm_suspend_request(rq)) {
288                 blk_stop_queue(drive->queue);
289         } else {
290                 drive->blocked = 0;
291                 blk_start_queue(drive->queue);
292         }
293         HWGROUP(drive)->rq = NULL;
294         if (__blk_end_request(rq, 0, 0))
295                 BUG();
296         spin_unlock_irqrestore(&ide_lock, flags);
297 }
298
299 /**
300  *      ide_end_drive_cmd       -       end an explicit drive command
301  *      @drive: command 
302  *      @stat: status bits
303  *      @err: error bits
304  *
305  *      Clean up after success/failure of an explicit drive command.
306  *      These get thrown onto the queue so they are synchronized with
307  *      real I/O operations on the drive.
308  *
309  *      In LBA48 mode we have to read the register set twice to get
310  *      all the extra information out.
311  */
312  
313 void ide_end_drive_cmd (ide_drive_t *drive, u8 stat, u8 err)
314 {
315         unsigned long flags;
316         struct request *rq;
317
318         spin_lock_irqsave(&ide_lock, flags);
319         rq = HWGROUP(drive)->rq;
320         spin_unlock_irqrestore(&ide_lock, flags);
321
322         if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
323                 ide_task_t *task = (ide_task_t *)rq->special;
324
325                 if (rq->errors == 0)
326                         rq->errors = !OK_STAT(stat, ATA_DRDY, BAD_STAT);
327
328                 if (task) {
329                         struct ide_taskfile *tf = &task->tf;
330
331                         tf->error = err;
332                         tf->status = stat;
333
334                         drive->hwif->tp_ops->tf_read(drive, task);
335
336                         if (task->tf_flags & IDE_TFLAG_DYN)
337                                 kfree(task);
338                 }
339         } else if (blk_pm_request(rq)) {
340                 struct request_pm_state *pm = rq->data;
341 #ifdef DEBUG_PM
342                 printk("%s: complete_power_step(step: %d, stat: %x, err: %x)\n",
343                         drive->name, rq->pm->pm_step, stat, err);
344 #endif
345                 ide_complete_power_step(drive, rq, stat, err);
346                 if (pm->pm_step == ide_pm_state_completed)
347                         ide_complete_pm_request(drive, rq);
348                 return;
349         }
350
351         spin_lock_irqsave(&ide_lock, flags);
352         HWGROUP(drive)->rq = NULL;
353         rq->errors = err;
354         if (unlikely(__blk_end_request(rq, (rq->errors ? -EIO : 0),
355                                        blk_rq_bytes(rq))))
356                 BUG();
357         spin_unlock_irqrestore(&ide_lock, flags);
358 }
359
360 EXPORT_SYMBOL(ide_end_drive_cmd);
361
362 static void ide_kill_rq(ide_drive_t *drive, struct request *rq)
363 {
364         if (rq->rq_disk) {
365                 ide_driver_t *drv;
366
367                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
368                 drv->end_request(drive, 0, 0);
369         } else
370                 ide_end_request(drive, 0, 0);
371 }
372
373 static ide_startstop_t ide_ata_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
374 {
375         ide_hwif_t *hwif = drive->hwif;
376
377         if ((stat & ATA_BUSY) || ((stat & ATA_DF) && !drive->nowerr)) {
378                 /* other bits are useless when BUSY */
379                 rq->errors |= ERROR_RESET;
380         } else if (stat & ATA_ERR) {
381                 /* err has different meaning on cdrom and tape */
382                 if (err == ATA_ABORTED) {
383                         if (drive->select.b.lba &&
384                             /* some newer drives don't support ATA_CMD_INIT_DEV_PARAMS */
385                             hwif->tp_ops->read_status(hwif) == ATA_CMD_INIT_DEV_PARAMS)
386                                 return ide_stopped;
387                 } else if ((err & BAD_CRC) == BAD_CRC) {
388                         /* UDMA crc error, just retry the operation */
389                         drive->crc_count++;
390                 } else if (err & (ATA_BBK | ATA_UNC)) {
391                         /* retries won't help these */
392                         rq->errors = ERROR_MAX;
393                 } else if (err & ATA_TRK0NF) {
394                         /* help it find track zero */
395                         rq->errors |= ERROR_RECAL;
396                 }
397         }
398
399         if ((stat & ATA_DRQ) && rq_data_dir(rq) == READ &&
400             (hwif->host_flags & IDE_HFLAG_ERROR_STOPS_FIFO) == 0) {
401                 int nsect = drive->mult_count ? drive->mult_count : 1;
402
403                 ide_pad_transfer(drive, READ, nsect * SECTOR_SIZE);
404         }
405
406         if (rq->errors >= ERROR_MAX || blk_noretry_request(rq)) {
407                 ide_kill_rq(drive, rq);
408                 return ide_stopped;
409         }
410
411         if (hwif->tp_ops->read_status(hwif) & (ATA_BUSY | ATA_DRQ))
412                 rq->errors |= ERROR_RESET;
413
414         if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
415                 ++rq->errors;
416                 return ide_do_reset(drive);
417         }
418
419         if ((rq->errors & ERROR_RECAL) == ERROR_RECAL)
420                 drive->special.b.recalibrate = 1;
421
422         ++rq->errors;
423
424         return ide_stopped;
425 }
426
427 static ide_startstop_t ide_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
428 {
429         ide_hwif_t *hwif = drive->hwif;
430
431         if ((stat & ATA_BUSY) || ((stat & ATA_DF) && !drive->nowerr)) {
432                 /* other bits are useless when BUSY */
433                 rq->errors |= ERROR_RESET;
434         } else {
435                 /* add decoding error stuff */
436         }
437
438         if (hwif->tp_ops->read_status(hwif) & (ATA_BUSY | ATA_DRQ))
439                 /* force an abort */
440                 hwif->tp_ops->exec_command(hwif, ATA_CMD_IDLEIMMEDIATE);
441
442         if (rq->errors >= ERROR_MAX) {
443                 ide_kill_rq(drive, rq);
444         } else {
445                 if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
446                         ++rq->errors;
447                         return ide_do_reset(drive);
448                 }
449                 ++rq->errors;
450         }
451
452         return ide_stopped;
453 }
454
455 ide_startstop_t
456 __ide_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
457 {
458         if (drive->media == ide_disk)
459                 return ide_ata_error(drive, rq, stat, err);
460         return ide_atapi_error(drive, rq, stat, err);
461 }
462
463 EXPORT_SYMBOL_GPL(__ide_error);
464
465 /**
466  *      ide_error       -       handle an error on the IDE
467  *      @drive: drive the error occurred on
468  *      @msg: message to report
469  *      @stat: status bits
470  *
471  *      ide_error() takes action based on the error returned by the drive.
472  *      For normal I/O that may well include retries. We deal with
473  *      both new-style (taskfile) and old style command handling here.
474  *      In the case of taskfile command handling there is work left to
475  *      do
476  */
477  
478 ide_startstop_t ide_error (ide_drive_t *drive, const char *msg, u8 stat)
479 {
480         struct request *rq;
481         u8 err;
482
483         err = ide_dump_status(drive, msg, stat);
484
485         if ((rq = HWGROUP(drive)->rq) == NULL)
486                 return ide_stopped;
487
488         /* retry only "normal" I/O: */
489         if (!blk_fs_request(rq)) {
490                 rq->errors = 1;
491                 ide_end_drive_cmd(drive, stat, err);
492                 return ide_stopped;
493         }
494
495         if (rq->rq_disk) {
496                 ide_driver_t *drv;
497
498                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
499                 return drv->error(drive, rq, stat, err);
500         } else
501                 return __ide_error(drive, rq, stat, err);
502 }
503
504 EXPORT_SYMBOL_GPL(ide_error);
505
506 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
507 {
508         tf->nsect   = drive->sect;
509         tf->lbal    = drive->sect;
510         tf->lbam    = drive->cyl;
511         tf->lbah    = drive->cyl >> 8;
512         tf->device  = ((drive->head - 1) | drive->select.all) & ~ATA_LBA;
513         tf->command = ATA_CMD_INIT_DEV_PARAMS;
514 }
515
516 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
517 {
518         tf->nsect   = drive->sect;
519         tf->command = ATA_CMD_RESTORE;
520 }
521
522 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
523 {
524         tf->nsect   = drive->mult_req;
525         tf->command = ATA_CMD_SET_MULTI;
526 }
527
528 static ide_startstop_t ide_disk_special(ide_drive_t *drive)
529 {
530         special_t *s = &drive->special;
531         ide_task_t args;
532
533         memset(&args, 0, sizeof(ide_task_t));
534         args.data_phase = TASKFILE_NO_DATA;
535
536         if (s->b.set_geometry) {
537                 s->b.set_geometry = 0;
538                 ide_tf_set_specify_cmd(drive, &args.tf);
539         } else if (s->b.recalibrate) {
540                 s->b.recalibrate = 0;
541                 ide_tf_set_restore_cmd(drive, &args.tf);
542         } else if (s->b.set_multmode) {
543                 s->b.set_multmode = 0;
544                 ide_tf_set_setmult_cmd(drive, &args.tf);
545         } else if (s->all) {
546                 int special = s->all;
547                 s->all = 0;
548                 printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special);
549                 return ide_stopped;
550         }
551
552         args.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE |
553                         IDE_TFLAG_CUSTOM_HANDLER;
554
555         do_rw_taskfile(drive, &args);
556
557         return ide_started;
558 }
559
560 /*
561  * handle HDIO_SET_PIO_MODE ioctl abusers here, eventually it will go away
562  */
563 static int set_pio_mode_abuse(ide_hwif_t *hwif, u8 req_pio)
564 {
565         switch (req_pio) {
566         case 202:
567         case 201:
568         case 200:
569         case 102:
570         case 101:
571         case 100:
572                 return (hwif->host_flags & IDE_HFLAG_ABUSE_DMA_MODES) ? 1 : 0;
573         case 9:
574         case 8:
575                 return (hwif->host_flags & IDE_HFLAG_ABUSE_PREFETCH) ? 1 : 0;
576         case 7:
577         case 6:
578                 return (hwif->host_flags & IDE_HFLAG_ABUSE_FAST_DEVSEL) ? 1 : 0;
579         default:
580                 return 0;
581         }
582 }
583
584 /**
585  *      do_special              -       issue some special commands
586  *      @drive: drive the command is for
587  *
588  *      do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
589  *      ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
590  *
591  *      It used to do much more, but has been scaled back.
592  */
593
594 static ide_startstop_t do_special (ide_drive_t *drive)
595 {
596         special_t *s = &drive->special;
597
598 #ifdef DEBUG
599         printk("%s: do_special: 0x%02x\n", drive->name, s->all);
600 #endif
601         if (s->b.set_tune) {
602                 ide_hwif_t *hwif = drive->hwif;
603                 const struct ide_port_ops *port_ops = hwif->port_ops;
604                 u8 req_pio = drive->tune_req;
605
606                 s->b.set_tune = 0;
607
608                 if (set_pio_mode_abuse(drive->hwif, req_pio)) {
609                         /*
610                          * take ide_lock for drive->[no_]unmask/[no_]io_32bit
611                          */
612                         if (req_pio == 8 || req_pio == 9) {
613                                 unsigned long flags;
614
615                                 spin_lock_irqsave(&ide_lock, flags);
616                                 port_ops->set_pio_mode(drive, req_pio);
617                                 spin_unlock_irqrestore(&ide_lock, flags);
618                         } else
619                                 port_ops->set_pio_mode(drive, req_pio);
620                 } else {
621                         int keep_dma = drive->using_dma;
622
623                         ide_set_pio(drive, req_pio);
624
625                         if (hwif->host_flags & IDE_HFLAG_SET_PIO_MODE_KEEP_DMA) {
626                                 if (keep_dma)
627                                         ide_dma_on(drive);
628                         }
629                 }
630
631                 return ide_stopped;
632         } else {
633                 if (drive->media == ide_disk)
634                         return ide_disk_special(drive);
635
636                 s->all = 0;
637                 drive->mult_req = 0;
638                 return ide_stopped;
639         }
640 }
641
642 void ide_map_sg(ide_drive_t *drive, struct request *rq)
643 {
644         ide_hwif_t *hwif = drive->hwif;
645         struct scatterlist *sg = hwif->sg_table;
646
647         if (hwif->sg_mapped)    /* needed by ide-scsi */
648                 return;
649
650         if (rq->cmd_type != REQ_TYPE_ATA_TASKFILE) {
651                 hwif->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
652         } else {
653                 sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
654                 hwif->sg_nents = 1;
655         }
656 }
657
658 EXPORT_SYMBOL_GPL(ide_map_sg);
659
660 void ide_init_sg_cmd(ide_drive_t *drive, struct request *rq)
661 {
662         ide_hwif_t *hwif = drive->hwif;
663
664         hwif->nsect = hwif->nleft = rq->nr_sectors;
665         hwif->cursg_ofs = 0;
666         hwif->cursg = NULL;
667 }
668
669 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
670
671 /**
672  *      execute_drive_command   -       issue special drive command
673  *      @drive: the drive to issue the command on
674  *      @rq: the request structure holding the command
675  *
676  *      execute_drive_cmd() issues a special drive command,  usually 
677  *      initiated by ioctl() from the external hdparm program. The
678  *      command can be a drive command, drive task or taskfile 
679  *      operation. Weirdly you can call it with NULL to wait for
680  *      all commands to finish. Don't do this as that is due to change
681  */
682
683 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
684                 struct request *rq)
685 {
686         ide_hwif_t *hwif = HWIF(drive);
687         ide_task_t *task = rq->special;
688
689         if (task) {
690                 hwif->data_phase = task->data_phase;
691
692                 switch (hwif->data_phase) {
693                 case TASKFILE_MULTI_OUT:
694                 case TASKFILE_OUT:
695                 case TASKFILE_MULTI_IN:
696                 case TASKFILE_IN:
697                         ide_init_sg_cmd(drive, rq);
698                         ide_map_sg(drive, rq);
699                 default:
700                         break;
701                 }
702
703                 return do_rw_taskfile(drive, task);
704         }
705
706         /*
707          * NULL is actually a valid way of waiting for
708          * all current requests to be flushed from the queue.
709          */
710 #ifdef DEBUG
711         printk("%s: DRIVE_CMD (null)\n", drive->name);
712 #endif
713         ide_end_drive_cmd(drive, hwif->tp_ops->read_status(hwif),
714                           ide_read_error(drive));
715
716         return ide_stopped;
717 }
718
719 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
720 {
721         switch (rq->cmd[0]) {
722         case REQ_DRIVE_RESET:
723                 return ide_do_reset(drive);
724         default:
725                 blk_dump_rq_flags(rq, "ide_special_rq - bad request");
726                 ide_end_request(drive, 0, 0);
727                 return ide_stopped;
728         }
729 }
730
731 static void ide_check_pm_state(ide_drive_t *drive, struct request *rq)
732 {
733         struct request_pm_state *pm = rq->data;
734
735         if (blk_pm_suspend_request(rq) &&
736             pm->pm_step == ide_pm_state_start_suspend)
737                 /* Mark drive blocked when starting the suspend sequence. */
738                 drive->blocked = 1;
739         else if (blk_pm_resume_request(rq) &&
740                  pm->pm_step == ide_pm_state_start_resume) {
741                 /* 
742                  * The first thing we do on wakeup is to wait for BSY bit to
743                  * go away (with a looong timeout) as a drive on this hwif may
744                  * just be POSTing itself.
745                  * We do that before even selecting as the "other" device on
746                  * the bus may be broken enough to walk on our toes at this
747                  * point.
748                  */
749                 ide_hwif_t *hwif = drive->hwif;
750                 int rc;
751 #ifdef DEBUG_PM
752                 printk("%s: Wakeup request inited, waiting for !BSY...\n", drive->name);
753 #endif
754                 rc = ide_wait_not_busy(hwif, 35000);
755                 if (rc)
756                         printk(KERN_WARNING "%s: bus not ready on wakeup\n", drive->name);
757                 SELECT_DRIVE(drive);
758                 hwif->tp_ops->set_irq(hwif, 1);
759                 rc = ide_wait_not_busy(hwif, 100000);
760                 if (rc)
761                         printk(KERN_WARNING "%s: drive not ready on wakeup\n", drive->name);
762         }
763 }
764
765 /**
766  *      start_request   -       start of I/O and command issuing for IDE
767  *
768  *      start_request() initiates handling of a new I/O request. It
769  *      accepts commands and I/O (read/write) requests.
770  *
771  *      FIXME: this function needs a rename
772  */
773  
774 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
775 {
776         ide_startstop_t startstop;
777
778         BUG_ON(!blk_rq_started(rq));
779
780 #ifdef DEBUG
781         printk("%s: start_request: current=0x%08lx\n",
782                 HWIF(drive)->name, (unsigned long) rq);
783 #endif
784
785         /* bail early if we've exceeded max_failures */
786         if (drive->max_failures && (drive->failures > drive->max_failures)) {
787                 rq->cmd_flags |= REQ_FAILED;
788                 goto kill_rq;
789         }
790
791         if (blk_pm_request(rq))
792                 ide_check_pm_state(drive, rq);
793
794         SELECT_DRIVE(drive);
795         if (ide_wait_stat(&startstop, drive, drive->ready_stat,
796                           ATA_BUSY | ATA_DRQ, WAIT_READY)) {
797                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
798                 return startstop;
799         }
800         if (!drive->special.all) {
801                 ide_driver_t *drv;
802
803                 /*
804                  * We reset the drive so we need to issue a SETFEATURES.
805                  * Do it _after_ do_special() restored device parameters.
806                  */
807                 if (drive->current_speed == 0xff)
808                         ide_config_drive_speed(drive, drive->desired_speed);
809
810                 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
811                         return execute_drive_cmd(drive, rq);
812                 else if (blk_pm_request(rq)) {
813                         struct request_pm_state *pm = rq->data;
814 #ifdef DEBUG_PM
815                         printk("%s: start_power_step(step: %d)\n",
816                                 drive->name, rq->pm->pm_step);
817 #endif
818                         startstop = ide_start_power_step(drive, rq);
819                         if (startstop == ide_stopped &&
820                             pm->pm_step == ide_pm_state_completed)
821                                 ide_complete_pm_request(drive, rq);
822                         return startstop;
823                 } else if (!rq->rq_disk && blk_special_request(rq))
824                         /*
825                          * TODO: Once all ULDs have been modified to
826                          * check for specific op codes rather than
827                          * blindly accepting any special request, the
828                          * check for ->rq_disk above may be replaced
829                          * by a more suitable mechanism or even
830                          * dropped entirely.
831                          */
832                         return ide_special_rq(drive, rq);
833
834                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
835
836                 return drv->do_request(drive, rq, rq->sector);
837         }
838         return do_special(drive);
839 kill_rq:
840         ide_kill_rq(drive, rq);
841         return ide_stopped;
842 }
843
844 /**
845  *      ide_stall_queue         -       pause an IDE device
846  *      @drive: drive to stall
847  *      @timeout: time to stall for (jiffies)
848  *
849  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
850  *      to the hwgroup by sleeping for timeout jiffies.
851  */
852  
853 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
854 {
855         if (timeout > WAIT_WORSTCASE)
856                 timeout = WAIT_WORSTCASE;
857         drive->sleep = timeout + jiffies;
858         drive->sleeping = 1;
859 }
860
861 EXPORT_SYMBOL(ide_stall_queue);
862
863 #define WAKEUP(drive)   ((drive)->service_start + 2 * (drive)->service_time)
864
865 /**
866  *      choose_drive            -       select a drive to service
867  *      @hwgroup: hardware group to select on
868  *
869  *      choose_drive() selects the next drive which will be serviced.
870  *      This is necessary because the IDE layer can't issue commands
871  *      to both drives on the same cable, unlike SCSI.
872  */
873  
874 static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup)
875 {
876         ide_drive_t *drive, *best;
877
878 repeat: 
879         best = NULL;
880         drive = hwgroup->drive;
881
882         /*
883          * drive is doing pre-flush, ordered write, post-flush sequence. even
884          * though that is 3 requests, it must be seen as a single transaction.
885          * we must not preempt this drive until that is complete
886          */
887         if (blk_queue_flushing(drive->queue)) {
888                 /*
889                  * small race where queue could get replugged during
890                  * the 3-request flush cycle, just yank the plug since
891                  * we want it to finish asap
892                  */
893                 blk_remove_plug(drive->queue);
894                 return drive;
895         }
896
897         do {
898                 if ((!drive->sleeping || time_after_eq(jiffies, drive->sleep))
899                     && !elv_queue_empty(drive->queue)) {
900                         if (!best
901                          || (drive->sleeping && (!best->sleeping || time_before(drive->sleep, best->sleep)))
902                          || (!best->sleeping && time_before(WAKEUP(drive), WAKEUP(best))))
903                         {
904                                 if (!blk_queue_plugged(drive->queue))
905                                         best = drive;
906                         }
907                 }
908         } while ((drive = drive->next) != hwgroup->drive);
909         if (best && best->nice1 && !best->sleeping && best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) {
910                 long t = (signed long)(WAKEUP(best) - jiffies);
911                 if (t >= WAIT_MIN_SLEEP) {
912                 /*
913                  * We *may* have some time to spare, but first let's see if
914                  * someone can potentially benefit from our nice mood today..
915                  */
916                         drive = best->next;
917                         do {
918                                 if (!drive->sleeping
919                                  && time_before(jiffies - best->service_time, WAKEUP(drive))
920                                  && time_before(WAKEUP(drive), jiffies + t))
921                                 {
922                                         ide_stall_queue(best, min_t(long, t, 10 * WAIT_MIN_SLEEP));
923                                         goto repeat;
924                                 }
925                         } while ((drive = drive->next) != best);
926                 }
927         }
928         return best;
929 }
930
931 /*
932  * Issue a new request to a drive from hwgroup
933  * Caller must have already done spin_lock_irqsave(&ide_lock, ..);
934  *
935  * A hwgroup is a serialized group of IDE interfaces.  Usually there is
936  * exactly one hwif (interface) per hwgroup, but buggy controllers (eg. CMD640)
937  * may have both interfaces in a single hwgroup to "serialize" access.
938  * Or possibly multiple ISA interfaces can share a common IRQ by being grouped
939  * together into one hwgroup for serialized access.
940  *
941  * Note also that several hwgroups can end up sharing a single IRQ,
942  * possibly along with many other devices.  This is especially common in
943  * PCI-based systems with off-board IDE controller cards.
944  *
945  * The IDE driver uses the single global ide_lock spinlock to protect
946  * access to the request queues, and to protect the hwgroup->busy flag.
947  *
948  * The first thread into the driver for a particular hwgroup sets the
949  * hwgroup->busy flag to indicate that this hwgroup is now active,
950  * and then initiates processing of the top request from the request queue.
951  *
952  * Other threads attempting entry notice the busy setting, and will simply
953  * queue their new requests and exit immediately.  Note that hwgroup->busy
954  * remains set even when the driver is merely awaiting the next interrupt.
955  * Thus, the meaning is "this hwgroup is busy processing a request".
956  *
957  * When processing of a request completes, the completing thread or IRQ-handler
958  * will start the next request from the queue.  If no more work remains,
959  * the driver will clear the hwgroup->busy flag and exit.
960  *
961  * The ide_lock (spinlock) is used to protect all access to the
962  * hwgroup->busy flag, but is otherwise not needed for most processing in
963  * the driver.  This makes the driver much more friendlier to shared IRQs
964  * than previous designs, while remaining 100% (?) SMP safe and capable.
965  */
966 static void ide_do_request (ide_hwgroup_t *hwgroup, int masked_irq)
967 {
968         ide_drive_t     *drive;
969         ide_hwif_t      *hwif;
970         struct request  *rq;
971         ide_startstop_t startstop;
972         int             loops = 0;
973
974         /* for atari only: POSSIBLY BROKEN HERE(?) */
975         ide_get_lock(ide_intr, hwgroup);
976
977         /* caller must own ide_lock */
978         BUG_ON(!irqs_disabled());
979
980         while (!hwgroup->busy) {
981                 hwgroup->busy = 1;
982                 drive = choose_drive(hwgroup);
983                 if (drive == NULL) {
984                         int sleeping = 0;
985                         unsigned long sleep = 0; /* shut up, gcc */
986                         hwgroup->rq = NULL;
987                         drive = hwgroup->drive;
988                         do {
989                                 if (drive->sleeping && (!sleeping || time_before(drive->sleep, sleep))) {
990                                         sleeping = 1;
991                                         sleep = drive->sleep;
992                                 }
993                         } while ((drive = drive->next) != hwgroup->drive);
994                         if (sleeping) {
995                 /*
996                  * Take a short snooze, and then wake up this hwgroup again.
997                  * This gives other hwgroups on the same a chance to
998                  * play fairly with us, just in case there are big differences
999                  * in relative throughputs.. don't want to hog the cpu too much.
1000                  */
1001                                 if (time_before(sleep, jiffies + WAIT_MIN_SLEEP))
1002                                         sleep = jiffies + WAIT_MIN_SLEEP;
1003 #if 1
1004                                 if (timer_pending(&hwgroup->timer))
1005                                         printk(KERN_CRIT "ide_set_handler: timer already active\n");
1006 #endif
1007                                 /* so that ide_timer_expiry knows what to do */
1008                                 hwgroup->sleeping = 1;
1009                                 hwgroup->req_gen_timer = hwgroup->req_gen;
1010                                 mod_timer(&hwgroup->timer, sleep);
1011                                 /* we purposely leave hwgroup->busy==1
1012                                  * while sleeping */
1013                         } else {
1014                                 /* Ugly, but how can we sleep for the lock
1015                                  * otherwise? perhaps from tq_disk?
1016                                  */
1017
1018                                 /* for atari only */
1019                                 ide_release_lock();
1020                                 hwgroup->busy = 0;
1021                         }
1022
1023                         /* no more work for this hwgroup (for now) */
1024                         return;
1025                 }
1026         again:
1027                 hwif = HWIF(drive);
1028                 if (hwgroup->hwif->sharing_irq && hwif != hwgroup->hwif) {
1029                         /*
1030                          * set nIEN for previous hwif, drives in the
1031                          * quirk_list may not like intr setups/cleanups
1032                          */
1033                         if (drive->quirk_list != 1)
1034                                 hwif->tp_ops->set_irq(hwif, 0);
1035                 }
1036                 hwgroup->hwif = hwif;
1037                 hwgroup->drive = drive;
1038                 drive->sleeping = 0;
1039                 drive->service_start = jiffies;
1040
1041                 if (blk_queue_plugged(drive->queue)) {
1042                         printk(KERN_ERR "ide: huh? queue was plugged!\n");
1043                         break;
1044                 }
1045
1046                 /*
1047                  * we know that the queue isn't empty, but this can happen
1048                  * if the q->prep_rq_fn() decides to kill a request
1049                  */
1050                 rq = elv_next_request(drive->queue);
1051                 if (!rq) {
1052                         hwgroup->busy = 0;
1053                         break;
1054                 }
1055
1056                 /*
1057                  * Sanity: don't accept a request that isn't a PM request
1058                  * if we are currently power managed. This is very important as
1059                  * blk_stop_queue() doesn't prevent the elv_next_request()
1060                  * above to return us whatever is in the queue. Since we call
1061                  * ide_do_request() ourselves, we end up taking requests while
1062                  * the queue is blocked...
1063                  * 
1064                  * We let requests forced at head of queue with ide-preempt
1065                  * though. I hope that doesn't happen too much, hopefully not
1066                  * unless the subdriver triggers such a thing in its own PM
1067                  * state machine.
1068                  *
1069                  * We count how many times we loop here to make sure we service
1070                  * all drives in the hwgroup without looping for ever
1071                  */
1072                 if (drive->blocked && !blk_pm_request(rq) && !(rq->cmd_flags & REQ_PREEMPT)) {
1073                         drive = drive->next ? drive->next : hwgroup->drive;
1074                         if (loops++ < 4 && !blk_queue_plugged(drive->queue))
1075                                 goto again;
1076                         /* We clear busy, there should be no pending ATA command at this point. */
1077                         hwgroup->busy = 0;
1078                         break;
1079                 }
1080
1081                 hwgroup->rq = rq;
1082
1083                 /*
1084                  * Some systems have trouble with IDE IRQs arriving while
1085                  * the driver is still setting things up.  So, here we disable
1086                  * the IRQ used by this interface while the request is being started.
1087                  * This may look bad at first, but pretty much the same thing
1088                  * happens anyway when any interrupt comes in, IDE or otherwise
1089                  *  -- the kernel masks the IRQ while it is being handled.
1090                  */
1091                 if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq)
1092                         disable_irq_nosync(hwif->irq);
1093                 spin_unlock(&ide_lock);
1094                 local_irq_enable_in_hardirq();
1095                         /* allow other IRQs while we start this request */
1096                 startstop = start_request(drive, rq);
1097                 spin_lock_irq(&ide_lock);
1098                 if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq)
1099                         enable_irq(hwif->irq);
1100                 if (startstop == ide_stopped)
1101                         hwgroup->busy = 0;
1102         }
1103 }
1104
1105 /*
1106  * Passes the stuff to ide_do_request
1107  */
1108 void do_ide_request(struct request_queue *q)
1109 {
1110         ide_drive_t *drive = q->queuedata;
1111
1112         ide_do_request(HWGROUP(drive), IDE_NO_IRQ);
1113 }
1114
1115 /*
1116  * un-busy the hwgroup etc, and clear any pending DMA status. we want to
1117  * retry the current request in pio mode instead of risking tossing it
1118  * all away
1119  */
1120 static ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error)
1121 {
1122         ide_hwif_t *hwif = HWIF(drive);
1123         struct request *rq;
1124         ide_startstop_t ret = ide_stopped;
1125
1126         /*
1127          * end current dma transaction
1128          */
1129
1130         if (error < 0) {
1131                 printk(KERN_WARNING "%s: DMA timeout error\n", drive->name);
1132                 (void)hwif->dma_ops->dma_end(drive);
1133                 ret = ide_error(drive, "dma timeout error",
1134                                 hwif->tp_ops->read_status(hwif));
1135         } else {
1136                 printk(KERN_WARNING "%s: DMA timeout retry\n", drive->name);
1137                 hwif->dma_ops->dma_timeout(drive);
1138         }
1139
1140         /*
1141          * disable dma for now, but remember that we did so because of
1142          * a timeout -- we'll reenable after we finish this next request
1143          * (or rather the first chunk of it) in pio.
1144          */
1145         drive->retry_pio++;
1146         drive->state = DMA_PIO_RETRY;
1147         ide_dma_off_quietly(drive);
1148
1149         /*
1150          * un-busy drive etc (hwgroup->busy is cleared on return) and
1151          * make sure request is sane
1152          */
1153         rq = HWGROUP(drive)->rq;
1154
1155         if (!rq)
1156                 goto out;
1157
1158         HWGROUP(drive)->rq = NULL;
1159
1160         rq->errors = 0;
1161
1162         if (!rq->bio)
1163                 goto out;
1164
1165         rq->sector = rq->bio->bi_sector;
1166         rq->current_nr_sectors = bio_iovec(rq->bio)->bv_len >> 9;
1167         rq->hard_cur_sectors = rq->current_nr_sectors;
1168         rq->buffer = bio_data(rq->bio);
1169 out:
1170         return ret;
1171 }
1172
1173 /**
1174  *      ide_timer_expiry        -       handle lack of an IDE interrupt
1175  *      @data: timer callback magic (hwgroup)
1176  *
1177  *      An IDE command has timed out before the expected drive return
1178  *      occurred. At this point we attempt to clean up the current
1179  *      mess. If the current handler includes an expiry handler then
1180  *      we invoke the expiry handler, and providing it is happy the
1181  *      work is done. If that fails we apply generic recovery rules
1182  *      invoking the handler and checking the drive DMA status. We
1183  *      have an excessively incestuous relationship with the DMA
1184  *      logic that wants cleaning up.
1185  */
1186  
1187 void ide_timer_expiry (unsigned long data)
1188 {
1189         ide_hwgroup_t   *hwgroup = (ide_hwgroup_t *) data;
1190         ide_handler_t   *handler;
1191         ide_expiry_t    *expiry;
1192         unsigned long   flags;
1193         unsigned long   wait = -1;
1194
1195         spin_lock_irqsave(&ide_lock, flags);
1196
1197         if (((handler = hwgroup->handler) == NULL) ||
1198             (hwgroup->req_gen != hwgroup->req_gen_timer)) {
1199                 /*
1200                  * Either a marginal timeout occurred
1201                  * (got the interrupt just as timer expired),
1202                  * or we were "sleeping" to give other devices a chance.
1203                  * Either way, we don't really want to complain about anything.
1204                  */
1205                 if (hwgroup->sleeping) {
1206                         hwgroup->sleeping = 0;
1207                         hwgroup->busy = 0;
1208                 }
1209         } else {
1210                 ide_drive_t *drive = hwgroup->drive;
1211                 if (!drive) {
1212                         printk(KERN_ERR "ide_timer_expiry: hwgroup->drive was NULL\n");
1213                         hwgroup->handler = NULL;
1214                 } else {
1215                         ide_hwif_t *hwif;
1216                         ide_startstop_t startstop = ide_stopped;
1217                         if (!hwgroup->busy) {
1218                                 hwgroup->busy = 1;      /* paranoia */
1219                                 printk(KERN_ERR "%s: ide_timer_expiry: hwgroup->busy was 0 ??\n", drive->name);
1220                         }
1221                         if ((expiry = hwgroup->expiry) != NULL) {
1222                                 /* continue */
1223                                 if ((wait = expiry(drive)) > 0) {
1224                                         /* reset timer */
1225                                         hwgroup->timer.expires  = jiffies + wait;
1226                                         hwgroup->req_gen_timer = hwgroup->req_gen;
1227                                         add_timer(&hwgroup->timer);
1228                                         spin_unlock_irqrestore(&ide_lock, flags);
1229                                         return;
1230                                 }
1231                         }
1232                         hwgroup->handler = NULL;
1233                         /*
1234                          * We need to simulate a real interrupt when invoking
1235                          * the handler() function, which means we need to
1236                          * globally mask the specific IRQ:
1237                          */
1238                         spin_unlock(&ide_lock);
1239                         hwif  = HWIF(drive);
1240                         /* disable_irq_nosync ?? */
1241                         disable_irq(hwif->irq);
1242                         /* local CPU only,
1243                          * as if we were handling an interrupt */
1244                         local_irq_disable();
1245                         if (hwgroup->polling) {
1246                                 startstop = handler(drive);
1247                         } else if (drive_is_ready(drive)) {
1248                                 if (drive->waiting_for_dma)
1249                                         hwif->dma_ops->dma_lost_irq(drive);
1250                                 (void)ide_ack_intr(hwif);
1251                                 printk(KERN_WARNING "%s: lost interrupt\n", drive->name);
1252                                 startstop = handler(drive);
1253                         } else {
1254                                 if (drive->waiting_for_dma) {
1255                                         startstop = ide_dma_timeout_retry(drive, wait);
1256                                 } else
1257                                         startstop =
1258                                         ide_error(drive, "irq timeout",
1259                                                   hwif->tp_ops->read_status(hwif));
1260                         }
1261                         drive->service_time = jiffies - drive->service_start;
1262                         spin_lock_irq(&ide_lock);
1263                         enable_irq(hwif->irq);
1264                         if (startstop == ide_stopped)
1265                                 hwgroup->busy = 0;
1266                 }
1267         }
1268         ide_do_request(hwgroup, IDE_NO_IRQ);
1269         spin_unlock_irqrestore(&ide_lock, flags);
1270 }
1271
1272 /**
1273  *      unexpected_intr         -       handle an unexpected IDE interrupt
1274  *      @irq: interrupt line
1275  *      @hwgroup: hwgroup being processed
1276  *
1277  *      There's nothing really useful we can do with an unexpected interrupt,
1278  *      other than reading the status register (to clear it), and logging it.
1279  *      There should be no way that an irq can happen before we're ready for it,
1280  *      so we needn't worry much about losing an "important" interrupt here.
1281  *
1282  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
1283  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
1284  *      looks "good", we just ignore the interrupt completely.
1285  *
1286  *      This routine assumes __cli() is in effect when called.
1287  *
1288  *      If an unexpected interrupt happens on irq15 while we are handling irq14
1289  *      and if the two interfaces are "serialized" (CMD640), then it looks like
1290  *      we could screw up by interfering with a new request being set up for 
1291  *      irq15.
1292  *
1293  *      In reality, this is a non-issue.  The new command is not sent unless 
1294  *      the drive is ready to accept one, in which case we know the drive is
1295  *      not trying to interrupt us.  And ide_set_handler() is always invoked
1296  *      before completing the issuance of any new drive command, so we will not
1297  *      be accidentally invoked as a result of any valid command completion
1298  *      interrupt.
1299  *
1300  *      Note that we must walk the entire hwgroup here. We know which hwif
1301  *      is doing the current command, but we don't know which hwif burped
1302  *      mysteriously.
1303  */
1304  
1305 static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup)
1306 {
1307         u8 stat;
1308         ide_hwif_t *hwif = hwgroup->hwif;
1309
1310         /*
1311          * handle the unexpected interrupt
1312          */
1313         do {
1314                 if (hwif->irq == irq) {
1315                         stat = hwif->tp_ops->read_status(hwif);
1316
1317                         if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
1318                                 /* Try to not flood the console with msgs */
1319                                 static unsigned long last_msgtime, count;
1320                                 ++count;
1321                                 if (time_after(jiffies, last_msgtime + HZ)) {
1322                                         last_msgtime = jiffies;
1323                                         printk(KERN_ERR "%s%s: unexpected interrupt, "
1324                                                 "status=0x%02x, count=%ld\n",
1325                                                 hwif->name,
1326                                                 (hwif->next==hwgroup->hwif) ? "" : "(?)", stat, count);
1327                                 }
1328                         }
1329                 }
1330         } while ((hwif = hwif->next) != hwgroup->hwif);
1331 }
1332
1333 /**
1334  *      ide_intr        -       default IDE interrupt handler
1335  *      @irq: interrupt number
1336  *      @dev_id: hwif group
1337  *      @regs: unused weirdness from the kernel irq layer
1338  *
1339  *      This is the default IRQ handler for the IDE layer. You should
1340  *      not need to override it. If you do be aware it is subtle in
1341  *      places
1342  *
1343  *      hwgroup->hwif is the interface in the group currently performing
1344  *      a command. hwgroup->drive is the drive and hwgroup->handler is
1345  *      the IRQ handler to call. As we issue a command the handlers
1346  *      step through multiple states, reassigning the handler to the
1347  *      next step in the process. Unlike a smart SCSI controller IDE
1348  *      expects the main processor to sequence the various transfer
1349  *      stages. We also manage a poll timer to catch up with most
1350  *      timeout situations. There are still a few where the handlers
1351  *      don't ever decide to give up.
1352  *
1353  *      The handler eventually returns ide_stopped to indicate the
1354  *      request completed. At this point we issue the next request
1355  *      on the hwgroup and the process begins again.
1356  */
1357  
1358 irqreturn_t ide_intr (int irq, void *dev_id)
1359 {
1360         unsigned long flags;
1361         ide_hwgroup_t *hwgroup = (ide_hwgroup_t *)dev_id;
1362         ide_hwif_t *hwif;
1363         ide_drive_t *drive;
1364         ide_handler_t *handler;
1365         ide_startstop_t startstop;
1366
1367         spin_lock_irqsave(&ide_lock, flags);
1368         hwif = hwgroup->hwif;
1369
1370         if (!ide_ack_intr(hwif)) {
1371                 spin_unlock_irqrestore(&ide_lock, flags);
1372                 return IRQ_NONE;
1373         }
1374
1375         if ((handler = hwgroup->handler) == NULL || hwgroup->polling) {
1376                 /*
1377                  * Not expecting an interrupt from this drive.
1378                  * That means this could be:
1379                  *      (1) an interrupt from another PCI device
1380                  *      sharing the same PCI INT# as us.
1381                  * or   (2) a drive just entered sleep or standby mode,
1382                  *      and is interrupting to let us know.
1383                  * or   (3) a spurious interrupt of unknown origin.
1384                  *
1385                  * For PCI, we cannot tell the difference,
1386                  * so in that case we just ignore it and hope it goes away.
1387                  *
1388                  * FIXME: unexpected_intr should be hwif-> then we can
1389                  * remove all the ifdef PCI crap
1390                  */
1391 #ifdef CONFIG_BLK_DEV_IDEPCI
1392                 if (hwif->chipset != ide_pci)
1393 #endif  /* CONFIG_BLK_DEV_IDEPCI */
1394                 {
1395                         /*
1396                          * Probably not a shared PCI interrupt,
1397                          * so we can safely try to do something about it:
1398                          */
1399                         unexpected_intr(irq, hwgroup);
1400 #ifdef CONFIG_BLK_DEV_IDEPCI
1401                 } else {
1402                         /*
1403                          * Whack the status register, just in case
1404                          * we have a leftover pending IRQ.
1405                          */
1406                         (void)hwif->tp_ops->read_status(hwif);
1407 #endif /* CONFIG_BLK_DEV_IDEPCI */
1408                 }
1409                 spin_unlock_irqrestore(&ide_lock, flags);
1410                 return IRQ_NONE;
1411         }
1412         drive = hwgroup->drive;
1413         if (!drive) {
1414                 /*
1415                  * This should NEVER happen, and there isn't much
1416                  * we could do about it here.
1417                  *
1418                  * [Note - this can occur if the drive is hot unplugged]
1419                  */
1420                 spin_unlock_irqrestore(&ide_lock, flags);
1421                 return IRQ_HANDLED;
1422         }
1423         if (!drive_is_ready(drive)) {
1424                 /*
1425                  * This happens regularly when we share a PCI IRQ with
1426                  * another device.  Unfortunately, it can also happen
1427                  * with some buggy drives that trigger the IRQ before
1428                  * their status register is up to date.  Hopefully we have
1429                  * enough advance overhead that the latter isn't a problem.
1430                  */
1431                 spin_unlock_irqrestore(&ide_lock, flags);
1432                 return IRQ_NONE;
1433         }
1434         if (!hwgroup->busy) {
1435                 hwgroup->busy = 1;      /* paranoia */
1436                 printk(KERN_ERR "%s: ide_intr: hwgroup->busy was 0 ??\n", drive->name);
1437         }
1438         hwgroup->handler = NULL;
1439         hwgroup->req_gen++;
1440         del_timer(&hwgroup->timer);
1441         spin_unlock(&ide_lock);
1442
1443         /* Some controllers might set DMA INTR no matter DMA or PIO;
1444          * bmdma status might need to be cleared even for
1445          * PIO interrupts to prevent spurious/lost irq.
1446          */
1447         if (hwif->ide_dma_clear_irq && !(drive->waiting_for_dma))
1448                 /* ide_dma_end() needs bmdma status for error checking.
1449                  * So, skip clearing bmdma status here and leave it
1450                  * to ide_dma_end() if this is dma interrupt.
1451                  */
1452                 hwif->ide_dma_clear_irq(drive);
1453
1454         if (drive->unmask)
1455                 local_irq_enable_in_hardirq();
1456         /* service this interrupt, may set handler for next interrupt */
1457         startstop = handler(drive);
1458         spin_lock_irq(&ide_lock);
1459
1460         /*
1461          * Note that handler() may have set things up for another
1462          * interrupt to occur soon, but it cannot happen until
1463          * we exit from this routine, because it will be the
1464          * same irq as is currently being serviced here, and Linux
1465          * won't allow another of the same (on any CPU) until we return.
1466          */
1467         drive->service_time = jiffies - drive->service_start;
1468         if (startstop == ide_stopped) {
1469                 if (hwgroup->handler == NULL) { /* paranoia */
1470                         hwgroup->busy = 0;
1471                         ide_do_request(hwgroup, hwif->irq);
1472                 } else {
1473                         printk(KERN_ERR "%s: ide_intr: huh? expected NULL handler "
1474                                 "on exit\n", drive->name);
1475                 }
1476         }
1477         spin_unlock_irqrestore(&ide_lock, flags);
1478         return IRQ_HANDLED;
1479 }
1480
1481 /**
1482  *      ide_do_drive_cmd        -       issue IDE special command
1483  *      @drive: device to issue command
1484  *      @rq: request to issue
1485  *
1486  *      This function issues a special IDE device request
1487  *      onto the request queue.
1488  *
1489  *      the rq is queued at the head of the request queue, displacing
1490  *      the currently-being-processed request and this function
1491  *      returns immediately without waiting for the new rq to be
1492  *      completed.  This is VERY DANGEROUS, and is intended for
1493  *      careful use by the ATAPI tape/cdrom driver code.
1494  */
1495
1496 void ide_do_drive_cmd(ide_drive_t *drive, struct request *rq)
1497 {
1498         unsigned long flags;
1499         ide_hwgroup_t *hwgroup = HWGROUP(drive);
1500
1501         spin_lock_irqsave(&ide_lock, flags);
1502         hwgroup->rq = NULL;
1503         __elv_add_request(drive->queue, rq, ELEVATOR_INSERT_FRONT, 1);
1504         __generic_unplug_device(drive->queue);
1505         spin_unlock_irqrestore(&ide_lock, flags);
1506 }
1507
1508 EXPORT_SYMBOL(ide_do_drive_cmd);
1509
1510 void ide_pktcmd_tf_load(ide_drive_t *drive, u32 tf_flags, u16 bcount, u8 dma)
1511 {
1512         ide_hwif_t *hwif = drive->hwif;
1513         ide_task_t task;
1514
1515         memset(&task, 0, sizeof(task));
1516         task.tf_flags = IDE_TFLAG_OUT_LBAH | IDE_TFLAG_OUT_LBAM |
1517                         IDE_TFLAG_OUT_FEATURE | tf_flags;
1518         task.tf.feature = dma;          /* Use PIO/DMA */
1519         task.tf.lbam    = bcount & 0xff;
1520         task.tf.lbah    = (bcount >> 8) & 0xff;
1521
1522         ide_tf_dump(drive->name, &task.tf);
1523         hwif->tp_ops->set_irq(hwif, 1);
1524         SELECT_MASK(drive, 0);
1525         hwif->tp_ops->tf_load(drive, &task);
1526 }
1527
1528 EXPORT_SYMBOL_GPL(ide_pktcmd_tf_load);
1529
1530 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
1531 {
1532         ide_hwif_t *hwif = drive->hwif;
1533         u8 buf[4] = { 0 };
1534
1535         while (len > 0) {
1536                 if (write)
1537                         hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
1538                 else
1539                         hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
1540                 len -= 4;
1541         }
1542 }
1543 EXPORT_SYMBOL_GPL(ide_pad_transfer);