Merge branch 'x86-mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6] / drivers / s390 / char / tape_core.c
1 /*
2  *  drivers/s390/char/tape_core.c
3  *    basic function of the tape device driver
4  *
5  *  S390 and zSeries version
6  *    Copyright IBM Corp. 2001,2006
7  *    Author(s): Carsten Otte <cotte@de.ibm.com>
8  *               Michael Holzheu <holzheu@de.ibm.com>
9  *               Tuan Ngo-Anh <ngoanh@de.ibm.com>
10  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
11  *               Stefan Bader <shbader@de.ibm.com>
12  */
13
14 #define KMSG_COMPONENT "tape"
15 #include <linux/module.h>
16 #include <linux/init.h>      // for kernel parameters
17 #include <linux/kmod.h>      // for requesting modules
18 #include <linux/spinlock.h>  // for locks
19 #include <linux/vmalloc.h>
20 #include <linux/list.h>
21
22 #include <asm/types.h>       // for variable types
23
24 #define TAPE_DBF_AREA   tape_core_dbf
25
26 #include "tape.h"
27 #include "tape_std.h"
28
29 #define LONG_BUSY_TIMEOUT 180 /* seconds */
30
31 static void __tape_do_irq (struct ccw_device *, unsigned long, struct irb *);
32 static void tape_delayed_next_request(struct work_struct *);
33 static void tape_long_busy_timeout(unsigned long data);
34
35 /*
36  * One list to contain all tape devices of all disciplines, so
37  * we can assign the devices to minor numbers of the same major
38  * The list is protected by the rwlock
39  */
40 static LIST_HEAD(tape_device_list);
41 static DEFINE_RWLOCK(tape_device_lock);
42
43 /*
44  * Pointer to debug area.
45  */
46 debug_info_t *TAPE_DBF_AREA = NULL;
47 EXPORT_SYMBOL(TAPE_DBF_AREA);
48
49 /*
50  * Printable strings for tape enumerations.
51  */
52 const char *tape_state_verbose[TS_SIZE] =
53 {
54         [TS_UNUSED]   = "UNUSED",
55         [TS_IN_USE]   = "IN_USE",
56         [TS_BLKUSE]   = "BLKUSE",
57         [TS_INIT]     = "INIT  ",
58         [TS_NOT_OPER] = "NOT_OP"
59 };
60
61 const char *tape_op_verbose[TO_SIZE] =
62 {
63         [TO_BLOCK] = "BLK",     [TO_BSB] = "BSB",
64         [TO_BSF] = "BSF",       [TO_DSE] = "DSE",
65         [TO_FSB] = "FSB",       [TO_FSF] = "FSF",
66         [TO_LBL] = "LBL",       [TO_NOP] = "NOP",
67         [TO_RBA] = "RBA",       [TO_RBI] = "RBI",
68         [TO_RFO] = "RFO",       [TO_REW] = "REW",
69         [TO_RUN] = "RUN",       [TO_WRI] = "WRI",
70         [TO_WTM] = "WTM",       [TO_MSEN] = "MSN",
71         [TO_LOAD] = "LOA",      [TO_READ_CONFIG] = "RCF",
72         [TO_READ_ATTMSG] = "RAT",
73         [TO_DIS] = "DIS",       [TO_ASSIGN] = "ASS",
74         [TO_UNASSIGN] = "UAS",  [TO_CRYPT_ON] = "CON",
75         [TO_CRYPT_OFF] = "COF", [TO_KEKL_SET] = "KLS",
76         [TO_KEKL_QUERY] = "KLQ",[TO_RDC] = "RDC",
77 };
78
79 static int devid_to_int(struct ccw_dev_id *dev_id)
80 {
81         return dev_id->devno + (dev_id->ssid << 16);
82 }
83
84 /*
85  * Some channel attached tape specific attributes.
86  *
87  * FIXME: In the future the first_minor and blocksize attribute should be
88  *        replaced by a link to the cdev tree.
89  */
90 static ssize_t
91 tape_medium_state_show(struct device *dev, struct device_attribute *attr, char *buf)
92 {
93         struct tape_device *tdev;
94
95         tdev = (struct tape_device *) dev->driver_data;
96         return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->medium_state);
97 }
98
99 static
100 DEVICE_ATTR(medium_state, 0444, tape_medium_state_show, NULL);
101
102 static ssize_t
103 tape_first_minor_show(struct device *dev, struct device_attribute *attr, char *buf)
104 {
105         struct tape_device *tdev;
106
107         tdev = (struct tape_device *) dev->driver_data;
108         return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->first_minor);
109 }
110
111 static
112 DEVICE_ATTR(first_minor, 0444, tape_first_minor_show, NULL);
113
114 static ssize_t
115 tape_state_show(struct device *dev, struct device_attribute *attr, char *buf)
116 {
117         struct tape_device *tdev;
118
119         tdev = (struct tape_device *) dev->driver_data;
120         return scnprintf(buf, PAGE_SIZE, "%s\n", (tdev->first_minor < 0) ?
121                 "OFFLINE" : tape_state_verbose[tdev->tape_state]);
122 }
123
124 static
125 DEVICE_ATTR(state, 0444, tape_state_show, NULL);
126
127 static ssize_t
128 tape_operation_show(struct device *dev, struct device_attribute *attr, char *buf)
129 {
130         struct tape_device *tdev;
131         ssize_t rc;
132
133         tdev = (struct tape_device *) dev->driver_data;
134         if (tdev->first_minor < 0)
135                 return scnprintf(buf, PAGE_SIZE, "N/A\n");
136
137         spin_lock_irq(get_ccwdev_lock(tdev->cdev));
138         if (list_empty(&tdev->req_queue))
139                 rc = scnprintf(buf, PAGE_SIZE, "---\n");
140         else {
141                 struct tape_request *req;
142
143                 req = list_entry(tdev->req_queue.next, struct tape_request,
144                         list);
145                 rc = scnprintf(buf,PAGE_SIZE, "%s\n", tape_op_verbose[req->op]);
146         }
147         spin_unlock_irq(get_ccwdev_lock(tdev->cdev));
148         return rc;
149 }
150
151 static
152 DEVICE_ATTR(operation, 0444, tape_operation_show, NULL);
153
154 static ssize_t
155 tape_blocksize_show(struct device *dev, struct device_attribute *attr, char *buf)
156 {
157         struct tape_device *tdev;
158
159         tdev = (struct tape_device *) dev->driver_data;
160
161         return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->char_data.block_size);
162 }
163
164 static
165 DEVICE_ATTR(blocksize, 0444, tape_blocksize_show, NULL);
166
167 static struct attribute *tape_attrs[] = {
168         &dev_attr_medium_state.attr,
169         &dev_attr_first_minor.attr,
170         &dev_attr_state.attr,
171         &dev_attr_operation.attr,
172         &dev_attr_blocksize.attr,
173         NULL
174 };
175
176 static struct attribute_group tape_attr_group = {
177         .attrs = tape_attrs,
178 };
179
180 /*
181  * Tape state functions
182  */
183 void
184 tape_state_set(struct tape_device *device, enum tape_state newstate)
185 {
186         const char *str;
187
188         if (device->tape_state == TS_NOT_OPER) {
189                 DBF_EVENT(3, "ts_set err: not oper\n");
190                 return;
191         }
192         DBF_EVENT(4, "ts. dev:  %x\n", device->first_minor);
193         DBF_EVENT(4, "old ts:\t\n");
194         if (device->tape_state < TS_SIZE && device->tape_state >=0 )
195                 str = tape_state_verbose[device->tape_state];
196         else
197                 str = "UNKNOWN TS";
198         DBF_EVENT(4, "%s\n", str);
199         DBF_EVENT(4, "new ts:\t\n");
200         if (newstate < TS_SIZE && newstate >= 0)
201                 str = tape_state_verbose[newstate];
202         else
203                 str = "UNKNOWN TS";
204         DBF_EVENT(4, "%s\n", str);
205         device->tape_state = newstate;
206         wake_up(&device->state_change_wq);
207 }
208
209 void
210 tape_med_state_set(struct tape_device *device, enum tape_medium_state newstate)
211 {
212         if (device->medium_state == newstate)
213                 return;
214         switch(newstate){
215         case MS_UNLOADED:
216                 device->tape_generic_status |= GMT_DR_OPEN(~0);
217                 dev_info(&device->cdev->dev, "The tape cartridge has been "
218                         "successfully unloaded\n");
219                 break;
220         case MS_LOADED:
221                 device->tape_generic_status &= ~GMT_DR_OPEN(~0);
222                 dev_info(&device->cdev->dev, "A tape cartridge has been "
223                         "mounted\n");
224                 break;
225         default:
226                 // print nothing
227                 break;
228         }
229         device->medium_state = newstate;
230         wake_up(&device->state_change_wq);
231 }
232
233 /*
234  * Stop running ccw. Has to be called with the device lock held.
235  */
236 static int
237 __tape_cancel_io(struct tape_device *device, struct tape_request *request)
238 {
239         int retries;
240         int rc;
241
242         /* Check if interrupt has already been processed */
243         if (request->callback == NULL)
244                 return 0;
245
246         rc = 0;
247         for (retries = 0; retries < 5; retries++) {
248                 rc = ccw_device_clear(device->cdev, (long) request);
249
250                 switch (rc) {
251                         case 0:
252                                 request->status = TAPE_REQUEST_DONE;
253                                 return 0;
254                         case -EBUSY:
255                                 request->status = TAPE_REQUEST_CANCEL;
256                                 schedule_delayed_work(&device->tape_dnr, 0);
257                                 return 0;
258                         case -ENODEV:
259                                 DBF_EXCEPTION(2, "device gone, retry\n");
260                                 break;
261                         case -EIO:
262                                 DBF_EXCEPTION(2, "I/O error, retry\n");
263                                 break;
264                         default:
265                                 BUG();
266                 }
267         }
268
269         return rc;
270 }
271
272 /*
273  * Add device into the sorted list, giving it the first
274  * available minor number.
275  */
276 static int
277 tape_assign_minor(struct tape_device *device)
278 {
279         struct tape_device *tmp;
280         int minor;
281
282         minor = 0;
283         write_lock(&tape_device_lock);
284         list_for_each_entry(tmp, &tape_device_list, node) {
285                 if (minor < tmp->first_minor)
286                         break;
287                 minor += TAPE_MINORS_PER_DEV;
288         }
289         if (minor >= 256) {
290                 write_unlock(&tape_device_lock);
291                 return -ENODEV;
292         }
293         device->first_minor = minor;
294         list_add_tail(&device->node, &tmp->node);
295         write_unlock(&tape_device_lock);
296         return 0;
297 }
298
299 /* remove device from the list */
300 static void
301 tape_remove_minor(struct tape_device *device)
302 {
303         write_lock(&tape_device_lock);
304         list_del_init(&device->node);
305         device->first_minor = -1;
306         write_unlock(&tape_device_lock);
307 }
308
309 /*
310  * Set a device online.
311  *
312  * This function is called by the common I/O layer to move a device from the
313  * detected but offline into the online state.
314  * If we return an error (RC < 0) the device remains in the offline state. This
315  * can happen if the device is assigned somewhere else, for example.
316  */
317 int
318 tape_generic_online(struct tape_device *device,
319                    struct tape_discipline *discipline)
320 {
321         int rc;
322
323         DBF_LH(6, "tape_enable_device(%p, %p)\n", device, discipline);
324
325         if (device->tape_state != TS_INIT) {
326                 DBF_LH(3, "Tapestate not INIT (%d)\n", device->tape_state);
327                 return -EINVAL;
328         }
329
330         init_timer(&device->lb_timeout);
331         device->lb_timeout.function = tape_long_busy_timeout;
332
333         /* Let the discipline have a go at the device. */
334         device->discipline = discipline;
335         if (!try_module_get(discipline->owner)) {
336                 return -EINVAL;
337         }
338
339         rc = discipline->setup_device(device);
340         if (rc)
341                 goto out;
342         rc = tape_assign_minor(device);
343         if (rc)
344                 goto out_discipline;
345
346         rc = tapechar_setup_device(device);
347         if (rc)
348                 goto out_minor;
349         rc = tapeblock_setup_device(device);
350         if (rc)
351                 goto out_char;
352
353         tape_state_set(device, TS_UNUSED);
354
355         DBF_LH(3, "(%08x): Drive set online\n", device->cdev_id);
356
357         return 0;
358
359 out_char:
360         tapechar_cleanup_device(device);
361 out_discipline:
362         device->discipline->cleanup_device(device);
363         device->discipline = NULL;
364 out_minor:
365         tape_remove_minor(device);
366 out:
367         module_put(discipline->owner);
368         return rc;
369 }
370
371 static void
372 tape_cleanup_device(struct tape_device *device)
373 {
374         tapeblock_cleanup_device(device);
375         tapechar_cleanup_device(device);
376         device->discipline->cleanup_device(device);
377         module_put(device->discipline->owner);
378         tape_remove_minor(device);
379         tape_med_state_set(device, MS_UNKNOWN);
380 }
381
382 /*
383  * Set device offline.
384  *
385  * Called by the common I/O layer if the drive should set offline on user
386  * request. We may prevent this by returning an error.
387  * Manual offline is only allowed while the drive is not in use.
388  */
389 int
390 tape_generic_offline(struct ccw_device *cdev)
391 {
392         struct tape_device *device;
393
394         device = cdev->dev.driver_data;
395         if (!device) {
396                 return -ENODEV;
397         }
398
399         DBF_LH(3, "(%08x): tape_generic_offline(%p)\n",
400                 device->cdev_id, device);
401
402         spin_lock_irq(get_ccwdev_lock(device->cdev));
403         switch (device->tape_state) {
404                 case TS_INIT:
405                 case TS_NOT_OPER:
406                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
407                         break;
408                 case TS_UNUSED:
409                         tape_state_set(device, TS_INIT);
410                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
411                         tape_cleanup_device(device);
412                         break;
413                 default:
414                         DBF_EVENT(3, "(%08x): Set offline failed "
415                                 "- drive in use.\n",
416                                 device->cdev_id);
417                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
418                         return -EBUSY;
419         }
420
421         DBF_LH(3, "(%08x): Drive set offline.\n", device->cdev_id);
422         return 0;
423 }
424
425 /*
426  * Allocate memory for a new device structure.
427  */
428 static struct tape_device *
429 tape_alloc_device(void)
430 {
431         struct tape_device *device;
432
433         device = kzalloc(sizeof(struct tape_device), GFP_KERNEL);
434         if (device == NULL) {
435                 DBF_EXCEPTION(2, "ti:no mem\n");
436                 return ERR_PTR(-ENOMEM);
437         }
438         device->modeset_byte = kmalloc(1, GFP_KERNEL | GFP_DMA);
439         if (device->modeset_byte == NULL) {
440                 DBF_EXCEPTION(2, "ti:no mem\n");
441                 kfree(device);
442                 return ERR_PTR(-ENOMEM);
443         }
444         INIT_LIST_HEAD(&device->req_queue);
445         INIT_LIST_HEAD(&device->node);
446         init_waitqueue_head(&device->state_change_wq);
447         init_waitqueue_head(&device->wait_queue);
448         device->tape_state = TS_INIT;
449         device->medium_state = MS_UNKNOWN;
450         *device->modeset_byte = 0;
451         device->first_minor = -1;
452         atomic_set(&device->ref_count, 1);
453         INIT_DELAYED_WORK(&device->tape_dnr, tape_delayed_next_request);
454
455         return device;
456 }
457
458 /*
459  * Get a reference to an existing device structure. This will automatically
460  * increment the reference count.
461  */
462 struct tape_device *
463 tape_get_device_reference(struct tape_device *device)
464 {
465         DBF_EVENT(4, "tape_get_device_reference(%p) = %i\n", device,
466                 atomic_inc_return(&device->ref_count));
467
468         return device;
469 }
470
471 /*
472  * Decrease the reference counter of a devices structure. If the
473  * reference counter reaches zero free the device structure.
474  * The function returns a NULL pointer to be used by the caller
475  * for clearing reference pointers.
476  */
477 struct tape_device *
478 tape_put_device(struct tape_device *device)
479 {
480         int remain;
481
482         remain = atomic_dec_return(&device->ref_count);
483         if (remain > 0) {
484                 DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, remain);
485         } else {
486                 if (remain < 0) {
487                         DBF_EVENT(4, "put device without reference\n");
488                 } else {
489                         DBF_EVENT(4, "tape_free_device(%p)\n", device);
490                         kfree(device->modeset_byte);
491                         kfree(device);
492                 }
493         }
494
495         return NULL;                    
496 }
497
498 /*
499  * Find tape device by a device index.
500  */
501 struct tape_device *
502 tape_get_device(int devindex)
503 {
504         struct tape_device *device, *tmp;
505
506         device = ERR_PTR(-ENODEV);
507         read_lock(&tape_device_lock);
508         list_for_each_entry(tmp, &tape_device_list, node) {
509                 if (tmp->first_minor / TAPE_MINORS_PER_DEV == devindex) {
510                         device = tape_get_device_reference(tmp);
511                         break;
512                 }
513         }
514         read_unlock(&tape_device_lock);
515         return device;
516 }
517
518 /*
519  * Driverfs tape probe function.
520  */
521 int
522 tape_generic_probe(struct ccw_device *cdev)
523 {
524         struct tape_device *device;
525         int ret;
526         struct ccw_dev_id dev_id;
527
528         device = tape_alloc_device();
529         if (IS_ERR(device))
530                 return -ENODEV;
531         ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP);
532         ret = sysfs_create_group(&cdev->dev.kobj, &tape_attr_group);
533         if (ret) {
534                 tape_put_device(device);
535                 return ret;
536         }
537         cdev->dev.driver_data = device;
538         cdev->handler = __tape_do_irq;
539         device->cdev = cdev;
540         ccw_device_get_id(cdev, &dev_id);
541         device->cdev_id = devid_to_int(&dev_id);
542         return ret;
543 }
544
545 static void
546 __tape_discard_requests(struct tape_device *device)
547 {
548         struct tape_request *   request;
549         struct list_head *      l, *n;
550
551         list_for_each_safe(l, n, &device->req_queue) {
552                 request = list_entry(l, struct tape_request, list);
553                 if (request->status == TAPE_REQUEST_IN_IO)
554                         request->status = TAPE_REQUEST_DONE;
555                 list_del(&request->list);
556
557                 /* Decrease ref_count for removed request. */
558                 request->device = tape_put_device(device);
559                 request->rc = -EIO;
560                 if (request->callback != NULL)
561                         request->callback(request, request->callback_data);
562         }
563 }
564
565 /*
566  * Driverfs tape remove function.
567  *
568  * This function is called whenever the common I/O layer detects the device
569  * gone. This can happen at any time and we cannot refuse.
570  */
571 void
572 tape_generic_remove(struct ccw_device *cdev)
573 {
574         struct tape_device *    device;
575
576         device = cdev->dev.driver_data;
577         if (!device) {
578                 return;
579         }
580         DBF_LH(3, "(%08x): tape_generic_remove(%p)\n", device->cdev_id, cdev);
581
582         spin_lock_irq(get_ccwdev_lock(device->cdev));
583         switch (device->tape_state) {
584                 case TS_INIT:
585                         tape_state_set(device, TS_NOT_OPER);
586                 case TS_NOT_OPER:
587                         /*
588                          * Nothing to do.
589                          */
590                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
591                         break;
592                 case TS_UNUSED:
593                         /*
594                          * Need only to release the device.
595                          */
596                         tape_state_set(device, TS_NOT_OPER);
597                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
598                         tape_cleanup_device(device);
599                         break;
600                 default:
601                         /*
602                          * There may be requests on the queue. We will not get
603                          * an interrupt for a request that was running. So we
604                          * just post them all as I/O errors.
605                          */
606                         DBF_EVENT(3, "(%08x): Drive in use vanished!\n",
607                                 device->cdev_id);
608                         dev_warn(&device->cdev->dev, "A tape unit was detached"
609                                 " while in use\n");
610                         tape_state_set(device, TS_NOT_OPER);
611                         __tape_discard_requests(device);
612                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
613                         tape_cleanup_device(device);
614         }
615
616         if (cdev->dev.driver_data != NULL) {
617                 sysfs_remove_group(&cdev->dev.kobj, &tape_attr_group);
618                 cdev->dev.driver_data = tape_put_device(cdev->dev.driver_data);
619         }
620 }
621
622 /*
623  * Allocate a new tape ccw request
624  */
625 struct tape_request *
626 tape_alloc_request(int cplength, int datasize)
627 {
628         struct tape_request *request;
629
630         BUG_ON(datasize > PAGE_SIZE || (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
631
632         DBF_LH(6, "tape_alloc_request(%d, %d)\n", cplength, datasize);
633
634         request = kzalloc(sizeof(struct tape_request), GFP_KERNEL);
635         if (request == NULL) {
636                 DBF_EXCEPTION(1, "cqra nomem\n");
637                 return ERR_PTR(-ENOMEM);
638         }
639         /* allocate channel program */
640         if (cplength > 0) {
641                 request->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
642                                           GFP_ATOMIC | GFP_DMA);
643                 if (request->cpaddr == NULL) {
644                         DBF_EXCEPTION(1, "cqra nomem\n");
645                         kfree(request);
646                         return ERR_PTR(-ENOMEM);
647                 }
648         }
649         /* alloc small kernel buffer */
650         if (datasize > 0) {
651                 request->cpdata = kzalloc(datasize, GFP_KERNEL | GFP_DMA);
652                 if (request->cpdata == NULL) {
653                         DBF_EXCEPTION(1, "cqra nomem\n");
654                         kfree(request->cpaddr);
655                         kfree(request);
656                         return ERR_PTR(-ENOMEM);
657                 }
658         }
659         DBF_LH(6, "New request %p(%p/%p)\n", request, request->cpaddr,
660                 request->cpdata);
661
662         return request;
663 }
664
665 /*
666  * Free tape ccw request
667  */
668 void
669 tape_free_request (struct tape_request * request)
670 {
671         DBF_LH(6, "Free request %p\n", request);
672
673         if (request->device != NULL) {
674                 request->device = tape_put_device(request->device);
675         }
676         kfree(request->cpdata);
677         kfree(request->cpaddr);
678         kfree(request);
679 }
680
681 static int
682 __tape_start_io(struct tape_device *device, struct tape_request *request)
683 {
684         int rc;
685
686 #ifdef CONFIG_S390_TAPE_BLOCK
687         if (request->op == TO_BLOCK)
688                 device->discipline->check_locate(device, request);
689 #endif
690         rc = ccw_device_start(
691                 device->cdev,
692                 request->cpaddr,
693                 (unsigned long) request,
694                 0x00,
695                 request->options
696         );
697         if (rc == 0) {
698                 request->status = TAPE_REQUEST_IN_IO;
699         } else if (rc == -EBUSY) {
700                 /* The common I/O subsystem is currently busy. Retry later. */
701                 request->status = TAPE_REQUEST_QUEUED;
702                 schedule_delayed_work(&device->tape_dnr, 0);
703                 rc = 0;
704         } else {
705                 /* Start failed. Remove request and indicate failure. */
706                 DBF_EVENT(1, "tape: start request failed with RC = %i\n", rc);
707         }
708         return rc;
709 }
710
711 static void
712 __tape_start_next_request(struct tape_device *device)
713 {
714         struct list_head *l, *n;
715         struct tape_request *request;
716         int rc;
717
718         DBF_LH(6, "__tape_start_next_request(%p)\n", device);
719         /*
720          * Try to start each request on request queue until one is
721          * started successful.
722          */
723         list_for_each_safe(l, n, &device->req_queue) {
724                 request = list_entry(l, struct tape_request, list);
725
726                 /*
727                  * Avoid race condition if bottom-half was triggered more than
728                  * once.
729                  */
730                 if (request->status == TAPE_REQUEST_IN_IO)
731                         return;
732                 /*
733                  * Request has already been stopped. We have to wait until
734                  * the request is removed from the queue in the interrupt
735                  * handling.
736                  */
737                 if (request->status == TAPE_REQUEST_DONE)
738                         return;
739
740                 /*
741                  * We wanted to cancel the request but the common I/O layer
742                  * was busy at that time. This can only happen if this
743                  * function is called by delayed_next_request.
744                  * Otherwise we start the next request on the queue.
745                  */
746                 if (request->status == TAPE_REQUEST_CANCEL) {
747                         rc = __tape_cancel_io(device, request);
748                 } else {
749                         rc = __tape_start_io(device, request);
750                 }
751                 if (rc == 0)
752                         return;
753
754                 /* Set ending status. */
755                 request->rc = rc;
756                 request->status = TAPE_REQUEST_DONE;
757
758                 /* Remove from request queue. */
759                 list_del(&request->list);
760
761                 /* Do callback. */
762                 if (request->callback != NULL)
763                         request->callback(request, request->callback_data);
764         }
765 }
766
767 static void
768 tape_delayed_next_request(struct work_struct *work)
769 {
770         struct tape_device *device =
771                 container_of(work, struct tape_device, tape_dnr.work);
772
773         DBF_LH(6, "tape_delayed_next_request(%p)\n", device);
774         spin_lock_irq(get_ccwdev_lock(device->cdev));
775         __tape_start_next_request(device);
776         spin_unlock_irq(get_ccwdev_lock(device->cdev));
777 }
778
779 static void tape_long_busy_timeout(unsigned long data)
780 {
781         struct tape_request *request;
782         struct tape_device *device;
783
784         device = (struct tape_device *) data;
785         spin_lock_irq(get_ccwdev_lock(device->cdev));
786         request = list_entry(device->req_queue.next, struct tape_request, list);
787         BUG_ON(request->status != TAPE_REQUEST_LONG_BUSY);
788         DBF_LH(6, "%08x: Long busy timeout.\n", device->cdev_id);
789         __tape_start_next_request(device);
790         device->lb_timeout.data = (unsigned long) tape_put_device(device);
791         spin_unlock_irq(get_ccwdev_lock(device->cdev));
792 }
793
794 static void
795 __tape_end_request(
796         struct tape_device *    device,
797         struct tape_request *   request,
798         int                     rc)
799 {
800         DBF_LH(6, "__tape_end_request(%p, %p, %i)\n", device, request, rc);
801         if (request) {
802                 request->rc = rc;
803                 request->status = TAPE_REQUEST_DONE;
804
805                 /* Remove from request queue. */
806                 list_del(&request->list);
807
808                 /* Do callback. */
809                 if (request->callback != NULL)
810                         request->callback(request, request->callback_data);
811         }
812
813         /* Start next request. */
814         if (!list_empty(&device->req_queue))
815                 __tape_start_next_request(device);
816 }
817
818 /*
819  * Write sense data to dbf
820  */
821 void
822 tape_dump_sense_dbf(struct tape_device *device, struct tape_request *request,
823                     struct irb *irb)
824 {
825         unsigned int *sptr;
826         const char* op;
827
828         if (request != NULL)
829                 op = tape_op_verbose[request->op];
830         else
831                 op = "---";
832         DBF_EVENT(3, "DSTAT : %02x   CSTAT: %02x\n",
833                   irb->scsw.cmd.dstat, irb->scsw.cmd.cstat);
834         DBF_EVENT(3, "DEVICE: %08x OP\t: %s\n", device->cdev_id, op);
835         sptr = (unsigned int *) irb->ecw;
836         DBF_EVENT(3, "%08x %08x\n", sptr[0], sptr[1]);
837         DBF_EVENT(3, "%08x %08x\n", sptr[2], sptr[3]);
838         DBF_EVENT(3, "%08x %08x\n", sptr[4], sptr[5]);
839         DBF_EVENT(3, "%08x %08x\n", sptr[6], sptr[7]);
840 }
841
842 /*
843  * I/O helper function. Adds the request to the request queue
844  * and starts it if the tape is idle. Has to be called with
845  * the device lock held.
846  */
847 static int
848 __tape_start_request(struct tape_device *device, struct tape_request *request)
849 {
850         int rc;
851
852         switch (request->op) {
853                 case TO_MSEN:
854                 case TO_ASSIGN:
855                 case TO_UNASSIGN:
856                 case TO_READ_ATTMSG:
857                 case TO_RDC:
858                         if (device->tape_state == TS_INIT)
859                                 break;
860                         if (device->tape_state == TS_UNUSED)
861                                 break;
862                 default:
863                         if (device->tape_state == TS_BLKUSE)
864                                 break;
865                         if (device->tape_state != TS_IN_USE)
866                                 return -ENODEV;
867         }
868
869         /* Increase use count of device for the added request. */
870         request->device = tape_get_device_reference(device);
871
872         if (list_empty(&device->req_queue)) {
873                 /* No other requests are on the queue. Start this one. */
874                 rc = __tape_start_io(device, request);
875                 if (rc)
876                         return rc;
877
878                 DBF_LH(5, "Request %p added for execution.\n", request);
879                 list_add(&request->list, &device->req_queue);
880         } else {
881                 DBF_LH(5, "Request %p add to queue.\n", request);
882                 request->status = TAPE_REQUEST_QUEUED;
883                 list_add_tail(&request->list, &device->req_queue);
884         }
885         return 0;
886 }
887
888 /*
889  * Add the request to the request queue, try to start it if the
890  * tape is idle. Return without waiting for end of i/o.
891  */
892 int
893 tape_do_io_async(struct tape_device *device, struct tape_request *request)
894 {
895         int rc;
896
897         DBF_LH(6, "tape_do_io_async(%p, %p)\n", device, request);
898
899         spin_lock_irq(get_ccwdev_lock(device->cdev));
900         /* Add request to request queue and try to start it. */
901         rc = __tape_start_request(device, request);
902         spin_unlock_irq(get_ccwdev_lock(device->cdev));
903         return rc;
904 }
905
906 /*
907  * tape_do_io/__tape_wake_up
908  * Add the request to the request queue, try to start it if the
909  * tape is idle and wait uninterruptible for its completion.
910  */
911 static void
912 __tape_wake_up(struct tape_request *request, void *data)
913 {
914         request->callback = NULL;
915         wake_up((wait_queue_head_t *) data);
916 }
917
918 int
919 tape_do_io(struct tape_device *device, struct tape_request *request)
920 {
921         int rc;
922
923         spin_lock_irq(get_ccwdev_lock(device->cdev));
924         /* Setup callback */
925         request->callback = __tape_wake_up;
926         request->callback_data = &device->wait_queue;
927         /* Add request to request queue and try to start it. */
928         rc = __tape_start_request(device, request);
929         spin_unlock_irq(get_ccwdev_lock(device->cdev));
930         if (rc)
931                 return rc;
932         /* Request added to the queue. Wait for its completion. */
933         wait_event(device->wait_queue, (request->callback == NULL));
934         /* Get rc from request */
935         return request->rc;
936 }
937
938 /*
939  * tape_do_io_interruptible/__tape_wake_up_interruptible
940  * Add the request to the request queue, try to start it if the
941  * tape is idle and wait uninterruptible for its completion.
942  */
943 static void
944 __tape_wake_up_interruptible(struct tape_request *request, void *data)
945 {
946         request->callback = NULL;
947         wake_up_interruptible((wait_queue_head_t *) data);
948 }
949
950 int
951 tape_do_io_interruptible(struct tape_device *device,
952                          struct tape_request *request)
953 {
954         int rc;
955
956         spin_lock_irq(get_ccwdev_lock(device->cdev));
957         /* Setup callback */
958         request->callback = __tape_wake_up_interruptible;
959         request->callback_data = &device->wait_queue;
960         rc = __tape_start_request(device, request);
961         spin_unlock_irq(get_ccwdev_lock(device->cdev));
962         if (rc)
963                 return rc;
964         /* Request added to the queue. Wait for its completion. */
965         rc = wait_event_interruptible(device->wait_queue,
966                                       (request->callback == NULL));
967         if (rc != -ERESTARTSYS)
968                 /* Request finished normally. */
969                 return request->rc;
970
971         /* Interrupted by a signal. We have to stop the current request. */
972         spin_lock_irq(get_ccwdev_lock(device->cdev));
973         rc = __tape_cancel_io(device, request);
974         spin_unlock_irq(get_ccwdev_lock(device->cdev));
975         if (rc == 0) {
976                 /* Wait for the interrupt that acknowledges the halt. */
977                 do {
978                         rc = wait_event_interruptible(
979                                 device->wait_queue,
980                                 (request->callback == NULL)
981                         );
982                 } while (rc == -ERESTARTSYS);
983
984                 DBF_EVENT(3, "IO stopped on %08x\n", device->cdev_id);
985                 rc = -ERESTARTSYS;
986         }
987         return rc;
988 }
989
990 /*
991  * Stop running ccw.
992  */
993 int
994 tape_cancel_io(struct tape_device *device, struct tape_request *request)
995 {
996         int rc;
997
998         spin_lock_irq(get_ccwdev_lock(device->cdev));
999         rc = __tape_cancel_io(device, request);
1000         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1001         return rc;
1002 }
1003
1004 /*
1005  * Tape interrupt routine, called from the ccw_device layer
1006  */
1007 static void
1008 __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
1009 {
1010         struct tape_device *device;
1011         struct tape_request *request;
1012         int rc;
1013
1014         device = (struct tape_device *) cdev->dev.driver_data;
1015         if (device == NULL) {
1016                 return;
1017         }
1018         request = (struct tape_request *) intparm;
1019
1020         DBF_LH(6, "__tape_do_irq(device=%p, request=%p)\n", device, request);
1021
1022         /* On special conditions irb is an error pointer */
1023         if (IS_ERR(irb)) {
1024                 /* FIXME: What to do with the request? */
1025                 switch (PTR_ERR(irb)) {
1026                         case -ETIMEDOUT:
1027                                 DBF_LH(1, "(%s): Request timed out\n",
1028                                         dev_name(&cdev->dev));
1029                         case -EIO:
1030                                 __tape_end_request(device, request, -EIO);
1031                                 break;
1032                         default:
1033                                 DBF_LH(1, "(%s): Unexpected i/o error %li\n",
1034                                         dev_name(&cdev->dev),
1035                                         PTR_ERR(irb));
1036                 }
1037                 return;
1038         }
1039
1040         /*
1041          * If the condition code is not zero and the start function bit is
1042          * still set, this is an deferred error and the last start I/O did
1043          * not succeed. At this point the condition that caused the deferred
1044          * error might still apply. So we just schedule the request to be
1045          * started later.
1046          */
1047         if (irb->scsw.cmd.cc != 0 &&
1048             (irb->scsw.cmd.fctl & SCSW_FCTL_START_FUNC) &&
1049             (request->status == TAPE_REQUEST_IN_IO)) {
1050                 DBF_EVENT(3,"(%08x): deferred cc=%i, fctl=%i. restarting\n",
1051                         device->cdev_id, irb->scsw.cmd.cc, irb->scsw.cmd.fctl);
1052                 request->status = TAPE_REQUEST_QUEUED;
1053                 schedule_delayed_work(&device->tape_dnr, HZ);
1054                 return;
1055         }
1056
1057         /* May be an unsolicited irq */
1058         if(request != NULL)
1059                 request->rescnt = irb->scsw.cmd.count;
1060         else if ((irb->scsw.cmd.dstat == 0x85 || irb->scsw.cmd.dstat == 0x80) &&
1061                  !list_empty(&device->req_queue)) {
1062                 /* Not Ready to Ready after long busy ? */
1063                 struct tape_request *req;
1064                 req = list_entry(device->req_queue.next,
1065                                  struct tape_request, list);
1066                 if (req->status == TAPE_REQUEST_LONG_BUSY) {
1067                         DBF_EVENT(3, "(%08x): del timer\n", device->cdev_id);
1068                         if (del_timer(&device->lb_timeout)) {
1069                                 device->lb_timeout.data = (unsigned long)
1070                                         tape_put_device(device);
1071                                 __tape_start_next_request(device);
1072                         }
1073                         return;
1074                 }
1075         }
1076         if (irb->scsw.cmd.dstat != 0x0c) {
1077                 /* Set the 'ONLINE' flag depending on sense byte 1 */
1078                 if(*(((__u8 *) irb->ecw) + 1) & SENSE_DRIVE_ONLINE)
1079                         device->tape_generic_status |= GMT_ONLINE(~0);
1080                 else
1081                         device->tape_generic_status &= ~GMT_ONLINE(~0);
1082
1083                 /*
1084                  * Any request that does not come back with channel end
1085                  * and device end is unusual. Log the sense data.
1086                  */
1087                 DBF_EVENT(3,"-- Tape Interrupthandler --\n");
1088                 tape_dump_sense_dbf(device, request, irb);
1089         } else {
1090                 /* Upon normal completion the device _is_ online */
1091                 device->tape_generic_status |= GMT_ONLINE(~0);
1092         }
1093         if (device->tape_state == TS_NOT_OPER) {
1094                 DBF_EVENT(6, "tape:device is not operational\n");
1095                 return;
1096         }
1097
1098         /*
1099          * Request that were canceled still come back with an interrupt.
1100          * To detect these request the state will be set to TAPE_REQUEST_DONE.
1101          */
1102         if(request != NULL && request->status == TAPE_REQUEST_DONE) {
1103                 __tape_end_request(device, request, -EIO);
1104                 return;
1105         }
1106
1107         rc = device->discipline->irq(device, request, irb);
1108         /*
1109          * rc < 0 : request finished unsuccessfully.
1110          * rc == TAPE_IO_SUCCESS: request finished successfully.
1111          * rc == TAPE_IO_PENDING: request is still running. Ignore rc.
1112          * rc == TAPE_IO_RETRY: request finished but needs another go.
1113          * rc == TAPE_IO_STOP: request needs to get terminated.
1114          */
1115         switch (rc) {
1116                 case TAPE_IO_SUCCESS:
1117                         /* Upon normal completion the device _is_ online */
1118                         device->tape_generic_status |= GMT_ONLINE(~0);
1119                         __tape_end_request(device, request, rc);
1120                         break;
1121                 case TAPE_IO_PENDING:
1122                         break;
1123                 case TAPE_IO_LONG_BUSY:
1124                         device->lb_timeout.data =
1125                                 (unsigned long)tape_get_device_reference(device);
1126                         device->lb_timeout.expires = jiffies +
1127                                 LONG_BUSY_TIMEOUT * HZ;
1128                         DBF_EVENT(3, "(%08x): add timer\n", device->cdev_id);
1129                         add_timer(&device->lb_timeout);
1130                         request->status = TAPE_REQUEST_LONG_BUSY;
1131                         break;
1132                 case TAPE_IO_RETRY:
1133                         rc = __tape_start_io(device, request);
1134                         if (rc)
1135                                 __tape_end_request(device, request, rc);
1136                         break;
1137                 case TAPE_IO_STOP:
1138                         rc = __tape_cancel_io(device, request);
1139                         if (rc)
1140                                 __tape_end_request(device, request, rc);
1141                         break;
1142                 default:
1143                         if (rc > 0) {
1144                                 DBF_EVENT(6, "xunknownrc\n");
1145                                 __tape_end_request(device, request, -EIO);
1146                         } else {
1147                                 __tape_end_request(device, request, rc);
1148                         }
1149                         break;
1150         }
1151 }
1152
1153 /*
1154  * Tape device open function used by tape_char & tape_block frontends.
1155  */
1156 int
1157 tape_open(struct tape_device *device)
1158 {
1159         int rc;
1160
1161         spin_lock_irq(get_ccwdev_lock(device->cdev));
1162         if (device->tape_state == TS_NOT_OPER) {
1163                 DBF_EVENT(6, "TAPE:nodev\n");
1164                 rc = -ENODEV;
1165         } else if (device->tape_state == TS_IN_USE) {
1166                 DBF_EVENT(6, "TAPE:dbusy\n");
1167                 rc = -EBUSY;
1168         } else if (device->tape_state == TS_BLKUSE) {
1169                 DBF_EVENT(6, "TAPE:dbusy\n");
1170                 rc = -EBUSY;
1171         } else if (device->discipline != NULL &&
1172                    !try_module_get(device->discipline->owner)) {
1173                 DBF_EVENT(6, "TAPE:nodisc\n");
1174                 rc = -ENODEV;
1175         } else {
1176                 tape_state_set(device, TS_IN_USE);
1177                 rc = 0;
1178         }
1179         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1180         return rc;
1181 }
1182
1183 /*
1184  * Tape device release function used by tape_char & tape_block frontends.
1185  */
1186 int
1187 tape_release(struct tape_device *device)
1188 {
1189         spin_lock_irq(get_ccwdev_lock(device->cdev));
1190         if (device->tape_state == TS_IN_USE)
1191                 tape_state_set(device, TS_UNUSED);
1192         module_put(device->discipline->owner);
1193         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1194         return 0;
1195 }
1196
1197 /*
1198  * Execute a magnetic tape command a number of times.
1199  */
1200 int
1201 tape_mtop(struct tape_device *device, int mt_op, int mt_count)
1202 {
1203         tape_mtop_fn fn;
1204         int rc;
1205
1206         DBF_EVENT(6, "TAPE:mtio\n");
1207         DBF_EVENT(6, "TAPE:ioop: %x\n", mt_op);
1208         DBF_EVENT(6, "TAPE:arg:  %x\n", mt_count);
1209
1210         if (mt_op < 0 || mt_op >= TAPE_NR_MTOPS)
1211                 return -EINVAL;
1212         fn = device->discipline->mtop_array[mt_op];
1213         if (fn == NULL)
1214                 return -EINVAL;
1215
1216         /* We assume that the backends can handle count up to 500. */
1217         if (mt_op == MTBSR  || mt_op == MTFSR  || mt_op == MTFSF  ||
1218             mt_op == MTBSF  || mt_op == MTFSFM || mt_op == MTBSFM) {
1219                 rc = 0;
1220                 for (; mt_count > 500; mt_count -= 500)
1221                         if ((rc = fn(device, 500)) != 0)
1222                                 break;
1223                 if (rc == 0)
1224                         rc = fn(device, mt_count);
1225         } else
1226                 rc = fn(device, mt_count);
1227         return rc;
1228
1229 }
1230
1231 /*
1232  * Tape init function.
1233  */
1234 static int
1235 tape_init (void)
1236 {
1237         TAPE_DBF_AREA = debug_register ( "tape", 2, 2, 4*sizeof(long));
1238         debug_register_view(TAPE_DBF_AREA, &debug_sprintf_view);
1239 #ifdef DBF_LIKE_HELL
1240         debug_set_level(TAPE_DBF_AREA, 6);
1241 #endif
1242         DBF_EVENT(3, "tape init\n");
1243         tape_proc_init();
1244         tapechar_init ();
1245         tapeblock_init ();
1246         return 0;
1247 }
1248
1249 /*
1250  * Tape exit function.
1251  */
1252 static void
1253 tape_exit(void)
1254 {
1255         DBF_EVENT(6, "tape exit\n");
1256
1257         /* Get rid of the frontends */
1258         tapechar_exit();
1259         tapeblock_exit();
1260         tape_proc_cleanup();
1261         debug_unregister (TAPE_DBF_AREA);
1262 }
1263
1264 MODULE_AUTHOR("(C) 2001 IBM Deutschland Entwicklung GmbH by Carsten Otte and "
1265               "Michael Holzheu (cotte@de.ibm.com,holzheu@de.ibm.com)");
1266 MODULE_DESCRIPTION("Linux on zSeries channel attached tape device driver");
1267 MODULE_LICENSE("GPL");
1268
1269 module_init(tape_init);
1270 module_exit(tape_exit);
1271
1272 EXPORT_SYMBOL(tape_generic_remove);
1273 EXPORT_SYMBOL(tape_generic_probe);
1274 EXPORT_SYMBOL(tape_generic_online);
1275 EXPORT_SYMBOL(tape_generic_offline);
1276 EXPORT_SYMBOL(tape_put_device);
1277 EXPORT_SYMBOL(tape_get_device_reference);
1278 EXPORT_SYMBOL(tape_state_verbose);
1279 EXPORT_SYMBOL(tape_op_verbose);
1280 EXPORT_SYMBOL(tape_state_set);
1281 EXPORT_SYMBOL(tape_med_state_set);
1282 EXPORT_SYMBOL(tape_alloc_request);
1283 EXPORT_SYMBOL(tape_free_request);
1284 EXPORT_SYMBOL(tape_dump_sense_dbf);
1285 EXPORT_SYMBOL(tape_do_io);
1286 EXPORT_SYMBOL(tape_do_io_async);
1287 EXPORT_SYMBOL(tape_do_io_interruptible);
1288 EXPORT_SYMBOL(tape_cancel_io);
1289 EXPORT_SYMBOL(tape_mtop);