Merge branch 'misc' of master.kernel.org:/pub/scm/linux/kernel/git/galak/powerpc...
[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 (C) 2001,2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
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 #include <linux/config.h>
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 PRINTK_HEADER "TAPE_CORE: "
30
31 static void __tape_do_irq (struct ccw_device *, unsigned long, struct irb *);
32 static void tape_delayed_next_request(void * data);
33
34 /*
35  * One list to contain all tape devices of all disciplines, so
36  * we can assign the devices to minor numbers of the same major
37  * The list is protected by the rwlock
38  */
39 static struct list_head tape_device_list = LIST_HEAD_INIT(tape_device_list);
40 static DEFINE_RWLOCK(tape_device_lock);
41
42 /*
43  * Pointer to debug area.
44  */
45 debug_info_t *TAPE_DBF_AREA = NULL;
46 EXPORT_SYMBOL(TAPE_DBF_AREA);
47
48 /*
49  * Printable strings for tape enumerations.
50  */
51 const char *tape_state_verbose[TS_SIZE] =
52 {
53         [TS_UNUSED]   = "UNUSED",
54         [TS_IN_USE]   = "IN_USE",
55         [TS_BLKUSE]   = "BLKUSE",
56         [TS_INIT]     = "INIT  ",
57         [TS_NOT_OPER] = "NOT_OP"
58 };
59
60 const char *tape_op_verbose[TO_SIZE] =
61 {
62         [TO_BLOCK] = "BLK",     [TO_BSB] = "BSB",
63         [TO_BSF] = "BSF",       [TO_DSE] = "DSE",
64         [TO_FSB] = "FSB",       [TO_FSF] = "FSF",
65         [TO_LBL] = "LBL",       [TO_NOP] = "NOP",
66         [TO_RBA] = "RBA",       [TO_RBI] = "RBI",
67         [TO_RFO] = "RFO",       [TO_REW] = "REW",
68         [TO_RUN] = "RUN",       [TO_WRI] = "WRI",
69         [TO_WTM] = "WTM",       [TO_MSEN] = "MSN",
70         [TO_LOAD] = "LOA",      [TO_READ_CONFIG] = "RCF",
71         [TO_READ_ATTMSG] = "RAT",
72         [TO_DIS] = "DIS",       [TO_ASSIGN] = "ASS",
73         [TO_UNASSIGN] = "UAS"
74 };
75
76 static inline int
77 busid_to_int(char *bus_id)
78 {
79         int     dec;
80         int     d;
81         char *  s;
82
83         for(s = bus_id, d = 0; *s != '\0' && *s != '.'; s++)
84                 d = (d * 10) + (*s - '0');
85         dec = d;
86         for(s++, d = 0; *s != '\0' && *s != '.'; s++)
87                 d = (d * 10) + (*s - '0');
88         dec = (dec << 8) + d;
89
90         for(s++; *s != '\0'; s++) {
91                 if (*s >= '0' && *s <= '9') {
92                         d = *s - '0';
93                 } else if (*s >= 'a' && *s <= 'f') {
94                         d = *s - 'a' + 10;
95                 } else {
96                         d = *s - 'A' + 10;
97                 }
98                 dec = (dec << 4) + d;
99         }
100
101         return dec;
102 }
103
104 /*
105  * Some channel attached tape specific attributes.
106  *
107  * FIXME: In the future the first_minor and blocksize attribute should be
108  *        replaced by a link to the cdev tree.
109  */
110 static ssize_t
111 tape_medium_state_show(struct device *dev, struct device_attribute *attr, char *buf)
112 {
113         struct tape_device *tdev;
114
115         tdev = (struct tape_device *) dev->driver_data;
116         return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->medium_state);
117 }
118
119 static
120 DEVICE_ATTR(medium_state, 0444, tape_medium_state_show, NULL);
121
122 static ssize_t
123 tape_first_minor_show(struct device *dev, struct device_attribute *attr, char *buf)
124 {
125         struct tape_device *tdev;
126
127         tdev = (struct tape_device *) dev->driver_data;
128         return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->first_minor);
129 }
130
131 static
132 DEVICE_ATTR(first_minor, 0444, tape_first_minor_show, NULL);
133
134 static ssize_t
135 tape_state_show(struct device *dev, struct device_attribute *attr, char *buf)
136 {
137         struct tape_device *tdev;
138
139         tdev = (struct tape_device *) dev->driver_data;
140         return scnprintf(buf, PAGE_SIZE, "%s\n", (tdev->first_minor < 0) ?
141                 "OFFLINE" : tape_state_verbose[tdev->tape_state]);
142 }
143
144 static
145 DEVICE_ATTR(state, 0444, tape_state_show, NULL);
146
147 static ssize_t
148 tape_operation_show(struct device *dev, struct device_attribute *attr, char *buf)
149 {
150         struct tape_device *tdev;
151         ssize_t rc;
152
153         tdev = (struct tape_device *) dev->driver_data;
154         if (tdev->first_minor < 0)
155                 return scnprintf(buf, PAGE_SIZE, "N/A\n");
156
157         spin_lock_irq(get_ccwdev_lock(tdev->cdev));
158         if (list_empty(&tdev->req_queue))
159                 rc = scnprintf(buf, PAGE_SIZE, "---\n");
160         else {
161                 struct tape_request *req;
162
163                 req = list_entry(tdev->req_queue.next, struct tape_request,
164                         list);
165                 rc = scnprintf(buf,PAGE_SIZE, "%s\n", tape_op_verbose[req->op]);
166         }
167         spin_unlock_irq(get_ccwdev_lock(tdev->cdev));
168         return rc;
169 }
170
171 static
172 DEVICE_ATTR(operation, 0444, tape_operation_show, NULL);
173
174 static ssize_t
175 tape_blocksize_show(struct device *dev, struct device_attribute *attr, char *buf)
176 {
177         struct tape_device *tdev;
178
179         tdev = (struct tape_device *) dev->driver_data;
180
181         return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->char_data.block_size);
182 }
183
184 static
185 DEVICE_ATTR(blocksize, 0444, tape_blocksize_show, NULL);
186
187 static struct attribute *tape_attrs[] = {
188         &dev_attr_medium_state.attr,
189         &dev_attr_first_minor.attr,
190         &dev_attr_state.attr,
191         &dev_attr_operation.attr,
192         &dev_attr_blocksize.attr,
193         NULL
194 };
195
196 static struct attribute_group tape_attr_group = {
197         .attrs = tape_attrs,
198 };
199
200 /*
201  * Tape state functions
202  */
203 void
204 tape_state_set(struct tape_device *device, enum tape_state newstate)
205 {
206         const char *str;
207
208         if (device->tape_state == TS_NOT_OPER) {
209                 DBF_EVENT(3, "ts_set err: not oper\n");
210                 return;
211         }
212         DBF_EVENT(4, "ts. dev:  %x\n", device->first_minor);
213         DBF_EVENT(4, "old ts:\t\n");
214         if (device->tape_state < TS_SIZE && device->tape_state >=0 )
215                 str = tape_state_verbose[device->tape_state];
216         else
217                 str = "UNKNOWN TS";
218         DBF_EVENT(4, "%s\n", str);
219         DBF_EVENT(4, "new ts:\t\n");
220         if (newstate < TS_SIZE && newstate >= 0)
221                 str = tape_state_verbose[newstate];
222         else
223                 str = "UNKNOWN TS";
224         DBF_EVENT(4, "%s\n", str);
225         device->tape_state = newstate;
226         wake_up(&device->state_change_wq);
227 }
228
229 void
230 tape_med_state_set(struct tape_device *device, enum tape_medium_state newstate)
231 {
232         if (device->medium_state == newstate)
233                 return;
234         switch(newstate){
235         case MS_UNLOADED:
236                 device->tape_generic_status |= GMT_DR_OPEN(~0);
237                 PRINT_INFO("(%s): Tape is unloaded\n",
238                            device->cdev->dev.bus_id);
239                 break;
240         case MS_LOADED:
241                 device->tape_generic_status &= ~GMT_DR_OPEN(~0);
242                 PRINT_INFO("(%s): Tape has been mounted\n",
243                            device->cdev->dev.bus_id);
244                 break;
245         default:
246                 // print nothing
247                 break;
248         }
249         device->medium_state = newstate;
250         wake_up(&device->state_change_wq);
251 }
252
253 /*
254  * Stop running ccw. Has to be called with the device lock held.
255  */
256 static inline int
257 __tape_cancel_io(struct tape_device *device, struct tape_request *request)
258 {
259         int retries;
260         int rc;
261
262         /* Check if interrupt has already been processed */
263         if (request->callback == NULL)
264                 return 0;
265
266         rc = 0;
267         for (retries = 0; retries < 5; retries++) {
268                 rc = ccw_device_clear(device->cdev, (long) request);
269
270                 switch (rc) {
271                         case 0:
272                                 request->status = TAPE_REQUEST_DONE;
273                                 return 0;
274                         case -EBUSY:
275                                 request->status = TAPE_REQUEST_CANCEL;
276                                 schedule_work(&device->tape_dnr);
277                                 return 0;
278                         case -ENODEV:
279                                 DBF_EXCEPTION(2, "device gone, retry\n");
280                                 break;
281                         case -EIO:
282                                 DBF_EXCEPTION(2, "I/O error, retry\n");
283                                 break;
284                         default:
285                                 BUG();
286                 }
287         }
288
289         return rc;
290 }
291
292 /*
293  * Add device into the sorted list, giving it the first
294  * available minor number.
295  */
296 static int
297 tape_assign_minor(struct tape_device *device)
298 {
299         struct tape_device *tmp;
300         int minor;
301
302         minor = 0;
303         write_lock(&tape_device_lock);
304         list_for_each_entry(tmp, &tape_device_list, node) {
305                 if (minor < tmp->first_minor)
306                         break;
307                 minor += TAPE_MINORS_PER_DEV;
308         }
309         if (minor >= 256) {
310                 write_unlock(&tape_device_lock);
311                 return -ENODEV;
312         }
313         device->first_minor = minor;
314         list_add_tail(&device->node, &tmp->node);
315         write_unlock(&tape_device_lock);
316         return 0;
317 }
318
319 /* remove device from the list */
320 static void
321 tape_remove_minor(struct tape_device *device)
322 {
323         write_lock(&tape_device_lock);
324         list_del_init(&device->node);
325         device->first_minor = -1;
326         write_unlock(&tape_device_lock);
327 }
328
329 /*
330  * Set a device online.
331  *
332  * This function is called by the common I/O layer to move a device from the
333  * detected but offline into the online state.
334  * If we return an error (RC < 0) the device remains in the offline state. This
335  * can happen if the device is assigned somewhere else, for example.
336  */
337 int
338 tape_generic_online(struct tape_device *device,
339                    struct tape_discipline *discipline)
340 {
341         int rc;
342
343         DBF_LH(6, "tape_enable_device(%p, %p)\n", device, discipline);
344
345         if (device->tape_state != TS_INIT) {
346                 DBF_LH(3, "Tapestate not INIT (%d)\n", device->tape_state);
347                 return -EINVAL;
348         }
349
350         /* Let the discipline have a go at the device. */
351         device->discipline = discipline;
352         if (!try_module_get(discipline->owner)) {
353                 PRINT_ERR("Cannot get module. Module gone.\n");
354                 return -EINVAL;
355         }
356
357         rc = discipline->setup_device(device);
358         if (rc)
359                 goto out;
360         rc = tape_assign_minor(device);
361         if (rc)
362                 goto out_discipline;
363
364         rc = tapechar_setup_device(device);
365         if (rc)
366                 goto out_minor;
367         rc = tapeblock_setup_device(device);
368         if (rc)
369                 goto out_char;
370
371         tape_state_set(device, TS_UNUSED);
372
373         DBF_LH(3, "(%08x): Drive set online\n", device->cdev_id);
374
375         return 0;
376
377 out_char:
378         tapechar_cleanup_device(device);
379 out_discipline:
380         device->discipline->cleanup_device(device);
381         device->discipline = NULL;
382 out_minor:
383         tape_remove_minor(device);
384 out:
385         module_put(discipline->owner);
386         return rc;
387 }
388
389 static inline void
390 tape_cleanup_device(struct tape_device *device)
391 {
392         tapeblock_cleanup_device(device);
393         tapechar_cleanup_device(device);
394         device->discipline->cleanup_device(device);
395         module_put(device->discipline->owner);
396         tape_remove_minor(device);
397         tape_med_state_set(device, MS_UNKNOWN);
398 }
399
400 /*
401  * Set device offline.
402  *
403  * Called by the common I/O layer if the drive should set offline on user
404  * request. We may prevent this by returning an error.
405  * Manual offline is only allowed while the drive is not in use.
406  */
407 int
408 tape_generic_offline(struct tape_device *device)
409 {
410         if (!device) {
411                 PRINT_ERR("tape_generic_offline: no such device\n");
412                 return -ENODEV;
413         }
414
415         DBF_LH(3, "(%08x): tape_generic_offline(%p)\n",
416                 device->cdev_id, device);
417
418         spin_lock_irq(get_ccwdev_lock(device->cdev));
419         switch (device->tape_state) {
420                 case TS_INIT:
421                 case TS_NOT_OPER:
422                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
423                         break;
424                 case TS_UNUSED:
425                         tape_state_set(device, TS_INIT);
426                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
427                         tape_cleanup_device(device);
428                         break;
429                 default:
430                         DBF_EVENT(3, "(%08x): Set offline failed "
431                                 "- drive in use.\n",
432                                 device->cdev_id);
433                         PRINT_WARN("(%s): Set offline failed "
434                                 "- drive in use.\n",
435                                 device->cdev->dev.bus_id);
436                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
437                         return -EBUSY;
438         }
439
440         DBF_LH(3, "(%08x): Drive set offline.\n", device->cdev_id);
441         return 0;
442 }
443
444 /*
445  * Allocate memory for a new device structure.
446  */
447 static struct tape_device *
448 tape_alloc_device(void)
449 {
450         struct tape_device *device;
451
452         device = kzalloc(sizeof(struct tape_device), GFP_KERNEL);
453         if (device == NULL) {
454                 DBF_EXCEPTION(2, "ti:no mem\n");
455                 PRINT_INFO ("can't allocate memory for "
456                             "tape info structure\n");
457                 return ERR_PTR(-ENOMEM);
458         }
459         device->modeset_byte = kmalloc(1, GFP_KERNEL | GFP_DMA);
460         if (device->modeset_byte == NULL) {
461                 DBF_EXCEPTION(2, "ti:no mem\n");
462                 PRINT_INFO("can't allocate memory for modeset byte\n");
463                 kfree(device);
464                 return ERR_PTR(-ENOMEM);
465         }
466         INIT_LIST_HEAD(&device->req_queue);
467         INIT_LIST_HEAD(&device->node);
468         init_waitqueue_head(&device->state_change_wq);
469         device->tape_state = TS_INIT;
470         device->medium_state = MS_UNKNOWN;
471         *device->modeset_byte = 0;
472         device->first_minor = -1;
473         atomic_set(&device->ref_count, 1);
474         INIT_WORK(&device->tape_dnr, tape_delayed_next_request, device);
475
476         return device;
477 }
478
479 /*
480  * Get a reference to an existing device structure. This will automatically
481  * increment the reference count.
482  */
483 struct tape_device *
484 tape_get_device_reference(struct tape_device *device)
485 {
486         DBF_EVENT(4, "tape_get_device_reference(%p) = %i\n", device,
487                 atomic_inc_return(&device->ref_count));
488
489         return device;
490 }
491
492 /*
493  * Decrease the reference counter of a devices structure. If the
494  * reference counter reaches zero free the device structure.
495  * The function returns a NULL pointer to be used by the caller
496  * for clearing reference pointers.
497  */
498 struct tape_device *
499 tape_put_device(struct tape_device *device)
500 {
501         int remain;
502
503         remain = atomic_dec_return(&device->ref_count);
504         if (remain > 0) {
505                 DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, remain);
506         } else {
507                 if (remain < 0) {
508                         DBF_EVENT(4, "put device without reference\n");
509                         PRINT_ERR("put device without reference\n");
510                 } else {
511                         DBF_EVENT(4, "tape_free_device(%p)\n", device);
512                         kfree(device->modeset_byte);
513                         kfree(device);
514                 }
515         }
516
517         return NULL;                    
518 }
519
520 /*
521  * Find tape device by a device index.
522  */
523 struct tape_device *
524 tape_get_device(int devindex)
525 {
526         struct tape_device *device, *tmp;
527
528         device = ERR_PTR(-ENODEV);
529         read_lock(&tape_device_lock);
530         list_for_each_entry(tmp, &tape_device_list, node) {
531                 if (tmp->first_minor / TAPE_MINORS_PER_DEV == devindex) {
532                         device = tape_get_device_reference(tmp);
533                         break;
534                 }
535         }
536         read_unlock(&tape_device_lock);
537         return device;
538 }
539
540 /*
541  * Driverfs tape probe function.
542  */
543 int
544 tape_generic_probe(struct ccw_device *cdev)
545 {
546         struct tape_device *device;
547
548         device = tape_alloc_device();
549         if (IS_ERR(device))
550                 return -ENODEV;
551         PRINT_INFO("tape device %s found\n", cdev->dev.bus_id);
552         cdev->dev.driver_data = device;
553         device->cdev = cdev;
554         device->cdev_id = busid_to_int(cdev->dev.bus_id);
555         cdev->handler = __tape_do_irq;
556
557         ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP);
558         sysfs_create_group(&cdev->dev.kobj, &tape_attr_group);
559
560         return 0;
561 }
562
563 static inline void
564 __tape_discard_requests(struct tape_device *device)
565 {
566         struct tape_request *   request;
567         struct list_head *      l, *n;
568
569         list_for_each_safe(l, n, &device->req_queue) {
570                 request = list_entry(l, struct tape_request, list);
571                 if (request->status == TAPE_REQUEST_IN_IO)
572                         request->status = TAPE_REQUEST_DONE;
573                 list_del(&request->list);
574
575                 /* Decrease ref_count for removed request. */
576                 request->device = tape_put_device(device);
577                 request->rc = -EIO;
578                 if (request->callback != NULL)
579                         request->callback(request, request->callback_data);
580         }
581 }
582
583 /*
584  * Driverfs tape remove function.
585  *
586  * This function is called whenever the common I/O layer detects the device
587  * gone. This can happen at any time and we cannot refuse.
588  */
589 void
590 tape_generic_remove(struct ccw_device *cdev)
591 {
592         struct tape_device *    device;
593
594         device = cdev->dev.driver_data;
595         if (!device) {
596                 PRINT_ERR("No device pointer in tape_generic_remove!\n");
597                 return;
598         }
599         DBF_LH(3, "(%08x): tape_generic_remove(%p)\n", device->cdev_id, cdev);
600
601         spin_lock_irq(get_ccwdev_lock(device->cdev));
602         switch (device->tape_state) {
603                 case TS_INIT:
604                         tape_state_set(device, TS_NOT_OPER);
605                 case TS_NOT_OPER:
606                         /*
607                          * Nothing to do.
608                          */
609                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
610                         break;
611                 case TS_UNUSED:
612                         /*
613                          * Need only to release the device.
614                          */
615                         tape_state_set(device, TS_NOT_OPER);
616                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
617                         tape_cleanup_device(device);
618                         break;
619                 default:
620                         /*
621                          * There may be requests on the queue. We will not get
622                          * an interrupt for a request that was running. So we
623                          * just post them all as I/O errors.
624                          */
625                         DBF_EVENT(3, "(%08x): Drive in use vanished!\n",
626                                 device->cdev_id);
627                         PRINT_WARN("(%s): Drive in use vanished - "
628                                 "expect trouble!\n",
629                                 device->cdev->dev.bus_id);
630                         PRINT_WARN("State was %i\n", device->tape_state);
631                         tape_state_set(device, TS_NOT_OPER);
632                         __tape_discard_requests(device);
633                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
634                         tape_cleanup_device(device);
635         }
636
637         if (cdev->dev.driver_data != NULL) {
638                 sysfs_remove_group(&cdev->dev.kobj, &tape_attr_group);
639                 cdev->dev.driver_data = tape_put_device(cdev->dev.driver_data);
640         }
641 }
642
643 /*
644  * Allocate a new tape ccw request
645  */
646 struct tape_request *
647 tape_alloc_request(int cplength, int datasize)
648 {
649         struct tape_request *request;
650
651         if (datasize > PAGE_SIZE || (cplength*sizeof(struct ccw1)) > PAGE_SIZE)
652                 BUG();
653
654         DBF_LH(6, "tape_alloc_request(%d, %d)\n", cplength, datasize);
655
656         request = kzalloc(sizeof(struct tape_request), GFP_KERNEL);
657         if (request == NULL) {
658                 DBF_EXCEPTION(1, "cqra nomem\n");
659                 return ERR_PTR(-ENOMEM);
660         }
661         /* allocate channel program */
662         if (cplength > 0) {
663                 request->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
664                                           GFP_ATOMIC | GFP_DMA);
665                 if (request->cpaddr == NULL) {
666                         DBF_EXCEPTION(1, "cqra nomem\n");
667                         kfree(request);
668                         return ERR_PTR(-ENOMEM);
669                 }
670         }
671         /* alloc small kernel buffer */
672         if (datasize > 0) {
673                 request->cpdata = kzalloc(datasize, GFP_KERNEL | GFP_DMA);
674                 if (request->cpdata == NULL) {
675                         DBF_EXCEPTION(1, "cqra nomem\n");
676                         kfree(request->cpaddr);
677                         kfree(request);
678                         return ERR_PTR(-ENOMEM);
679                 }
680         }
681         DBF_LH(6, "New request %p(%p/%p)\n", request, request->cpaddr,
682                 request->cpdata);
683
684         return request;
685 }
686
687 /*
688  * Free tape ccw request
689  */
690 void
691 tape_free_request (struct tape_request * request)
692 {
693         DBF_LH(6, "Free request %p\n", request);
694
695         if (request->device != NULL) {
696                 request->device = tape_put_device(request->device);
697         }
698         kfree(request->cpdata);
699         kfree(request->cpaddr);
700         kfree(request);
701 }
702
703 static inline int
704 __tape_start_io(struct tape_device *device, struct tape_request *request)
705 {
706         int rc;
707
708 #ifdef CONFIG_S390_TAPE_BLOCK
709         if (request->op == TO_BLOCK)
710                 device->discipline->check_locate(device, request);
711 #endif
712         rc = ccw_device_start(
713                 device->cdev,
714                 request->cpaddr,
715                 (unsigned long) request,
716                 0x00,
717                 request->options
718         );
719         if (rc == 0) {
720                 request->status = TAPE_REQUEST_IN_IO;
721         } else if (rc == -EBUSY) {
722                 /* The common I/O subsystem is currently busy. Retry later. */
723                 request->status = TAPE_REQUEST_QUEUED;
724                 schedule_work(&device->tape_dnr);
725                 rc = 0;
726         } else {
727                 /* Start failed. Remove request and indicate failure. */
728                 DBF_EVENT(1, "tape: start request failed with RC = %i\n", rc);
729         }
730         return rc;
731 }
732
733 static inline void
734 __tape_start_next_request(struct tape_device *device)
735 {
736         struct list_head *l, *n;
737         struct tape_request *request;
738         int rc;
739
740         DBF_LH(6, "__tape_start_next_request(%p)\n", device);
741         /*
742          * Try to start each request on request queue until one is
743          * started successful.
744          */
745         list_for_each_safe(l, n, &device->req_queue) {
746                 request = list_entry(l, struct tape_request, list);
747
748                 /*
749                  * Avoid race condition if bottom-half was triggered more than
750                  * once.
751                  */
752                 if (request->status == TAPE_REQUEST_IN_IO)
753                         return;
754                 /*
755                  * Request has already been stopped. We have to wait until
756                  * the request is removed from the queue in the interrupt
757                  * handling.
758                  */
759                 if (request->status == TAPE_REQUEST_DONE)
760                         return;
761
762                 /*
763                  * We wanted to cancel the request but the common I/O layer
764                  * was busy at that time. This can only happen if this
765                  * function is called by delayed_next_request.
766                  * Otherwise we start the next request on the queue.
767                  */
768                 if (request->status == TAPE_REQUEST_CANCEL) {
769                         rc = __tape_cancel_io(device, request);
770                 } else {
771                         rc = __tape_start_io(device, request);
772                 }
773                 if (rc == 0)
774                         return;
775
776                 /* Set ending status. */
777                 request->rc = rc;
778                 request->status = TAPE_REQUEST_DONE;
779
780                 /* Remove from request queue. */
781                 list_del(&request->list);
782
783                 /* Do callback. */
784                 if (request->callback != NULL)
785                         request->callback(request, request->callback_data);
786         }
787 }
788
789 static void
790 tape_delayed_next_request(void *data)
791 {
792         struct tape_device *    device;
793
794         device = (struct tape_device *) data;
795         DBF_LH(6, "tape_delayed_next_request(%p)\n", device);
796         spin_lock_irq(get_ccwdev_lock(device->cdev));
797         __tape_start_next_request(device);
798         spin_unlock_irq(get_ccwdev_lock(device->cdev));
799 }
800
801 static inline void
802 __tape_end_request(
803         struct tape_device *    device,
804         struct tape_request *   request,
805         int                     rc)
806 {
807         DBF_LH(6, "__tape_end_request(%p, %p, %i)\n", device, request, rc);
808         if (request) {
809                 request->rc = rc;
810                 request->status = TAPE_REQUEST_DONE;
811
812                 /* Remove from request queue. */
813                 list_del(&request->list);
814
815                 /* Do callback. */
816                 if (request->callback != NULL)
817                         request->callback(request, request->callback_data);
818         }
819
820         /* Start next request. */
821         if (!list_empty(&device->req_queue))
822                 __tape_start_next_request(device);
823 }
824
825 /*
826  * Write sense data to console/dbf
827  */
828 void
829 tape_dump_sense(struct tape_device* device, struct tape_request *request,
830                 struct irb *irb)
831 {
832         unsigned int *sptr;
833
834         PRINT_INFO("-------------------------------------------------\n");
835         PRINT_INFO("DSTAT : %02x  CSTAT: %02x   CPA: %04x\n",
836                    irb->scsw.dstat, irb->scsw.cstat, irb->scsw.cpa);
837         PRINT_INFO("DEVICE: %s\n", device->cdev->dev.bus_id);
838         if (request != NULL)
839                 PRINT_INFO("OP    : %s\n", tape_op_verbose[request->op]);
840
841         sptr = (unsigned int *) irb->ecw;
842         PRINT_INFO("Sense data: %08X %08X %08X %08X \n",
843                    sptr[0], sptr[1], sptr[2], sptr[3]);
844         PRINT_INFO("Sense data: %08X %08X %08X %08X \n",
845                    sptr[4], sptr[5], sptr[6], sptr[7]);
846         PRINT_INFO("--------------------------------------------------\n");
847 }
848
849 /*
850  * Write sense data to dbf
851  */
852 void
853 tape_dump_sense_dbf(struct tape_device *device, struct tape_request *request,
854                     struct irb *irb)
855 {
856         unsigned int *sptr;
857         const char* op;
858
859         if (request != NULL)
860                 op = tape_op_verbose[request->op];
861         else
862                 op = "---";
863         DBF_EVENT(3, "DSTAT : %02x   CSTAT: %02x\n",
864                   irb->scsw.dstat,irb->scsw.cstat);
865         DBF_EVENT(3, "DEVICE: %08x OP\t: %s\n", device->cdev_id, op);
866         sptr = (unsigned int *) irb->ecw;
867         DBF_EVENT(3, "%08x %08x\n", sptr[0], sptr[1]);
868         DBF_EVENT(3, "%08x %08x\n", sptr[2], sptr[3]);
869         DBF_EVENT(3, "%08x %08x\n", sptr[4], sptr[5]);
870         DBF_EVENT(3, "%08x %08x\n", sptr[6], sptr[7]);
871 }
872
873 /*
874  * I/O helper function. Adds the request to the request queue
875  * and starts it if the tape is idle. Has to be called with
876  * the device lock held.
877  */
878 static inline int
879 __tape_start_request(struct tape_device *device, struct tape_request *request)
880 {
881         int rc;
882
883         switch (request->op) {
884                 case TO_MSEN:
885                 case TO_ASSIGN:
886                 case TO_UNASSIGN:
887                 case TO_READ_ATTMSG:
888                         if (device->tape_state == TS_INIT)
889                                 break;
890                         if (device->tape_state == TS_UNUSED)
891                                 break;
892                 default:
893                         if (device->tape_state == TS_BLKUSE)
894                                 break;
895                         if (device->tape_state != TS_IN_USE)
896                                 return -ENODEV;
897         }
898
899         /* Increase use count of device for the added request. */
900         request->device = tape_get_device_reference(device);
901
902         if (list_empty(&device->req_queue)) {
903                 /* No other requests are on the queue. Start this one. */
904                 rc = __tape_start_io(device, request);
905                 if (rc)
906                         return rc;
907
908                 DBF_LH(5, "Request %p added for execution.\n", request);
909                 list_add(&request->list, &device->req_queue);
910         } else {
911                 DBF_LH(5, "Request %p add to queue.\n", request);
912                 request->status = TAPE_REQUEST_QUEUED;
913                 list_add_tail(&request->list, &device->req_queue);
914         }
915         return 0;
916 }
917
918 /*
919  * Add the request to the request queue, try to start it if the
920  * tape is idle. Return without waiting for end of i/o.
921  */
922 int
923 tape_do_io_async(struct tape_device *device, struct tape_request *request)
924 {
925         int rc;
926
927         DBF_LH(6, "tape_do_io_async(%p, %p)\n", device, request);
928
929         spin_lock_irq(get_ccwdev_lock(device->cdev));
930         /* Add request to request queue and try to start it. */
931         rc = __tape_start_request(device, request);
932         spin_unlock_irq(get_ccwdev_lock(device->cdev));
933         return rc;
934 }
935
936 /*
937  * tape_do_io/__tape_wake_up
938  * Add the request to the request queue, try to start it if the
939  * tape is idle and wait uninterruptible for its completion.
940  */
941 static void
942 __tape_wake_up(struct tape_request *request, void *data)
943 {
944         request->callback = NULL;
945         wake_up((wait_queue_head_t *) data);
946 }
947
948 int
949 tape_do_io(struct tape_device *device, struct tape_request *request)
950 {
951         wait_queue_head_t wq;
952         int rc;
953
954         init_waitqueue_head(&wq);
955         spin_lock_irq(get_ccwdev_lock(device->cdev));
956         /* Setup callback */
957         request->callback = __tape_wake_up;
958         request->callback_data = &wq;
959         /* Add request to request queue and try to start it. */
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         wait_event(wq, (request->callback == NULL));
966         /* Get rc from request */
967         return request->rc;
968 }
969
970 /*
971  * tape_do_io_interruptible/__tape_wake_up_interruptible
972  * Add the request to the request queue, try to start it if the
973  * tape is idle and wait uninterruptible for its completion.
974  */
975 static void
976 __tape_wake_up_interruptible(struct tape_request *request, void *data)
977 {
978         request->callback = NULL;
979         wake_up_interruptible((wait_queue_head_t *) data);
980 }
981
982 int
983 tape_do_io_interruptible(struct tape_device *device,
984                          struct tape_request *request)
985 {
986         wait_queue_head_t wq;
987         int rc;
988
989         init_waitqueue_head(&wq);
990         spin_lock_irq(get_ccwdev_lock(device->cdev));
991         /* Setup callback */
992         request->callback = __tape_wake_up_interruptible;
993         request->callback_data = &wq;
994         rc = __tape_start_request(device, request);
995         spin_unlock_irq(get_ccwdev_lock(device->cdev));
996         if (rc)
997                 return rc;
998         /* Request added to the queue. Wait for its completion. */
999         rc = wait_event_interruptible(wq, (request->callback == NULL));
1000         if (rc != -ERESTARTSYS)
1001                 /* Request finished normally. */
1002                 return request->rc;
1003
1004         /* Interrupted by a signal. We have to stop the current request. */
1005         spin_lock_irq(get_ccwdev_lock(device->cdev));
1006         rc = __tape_cancel_io(device, request);
1007         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1008         if (rc == 0) {
1009                 /* Wait for the interrupt that acknowledges the halt. */
1010                 do {
1011                         rc = wait_event_interruptible(
1012                                 wq,
1013                                 (request->callback == NULL)
1014                         );
1015                 } while (rc == -ERESTARTSYS);
1016
1017                 DBF_EVENT(3, "IO stopped on %08x\n", device->cdev_id);
1018                 rc = -ERESTARTSYS;
1019         }
1020         return rc;
1021 }
1022
1023 /*
1024  * Stop running ccw.
1025  */
1026 int
1027 tape_cancel_io(struct tape_device *device, struct tape_request *request)
1028 {
1029         int rc;
1030
1031         spin_lock_irq(get_ccwdev_lock(device->cdev));
1032         rc = __tape_cancel_io(device, request);
1033         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1034         return rc;
1035 }
1036
1037 /*
1038  * Tape interrupt routine, called from the ccw_device layer
1039  */
1040 static void
1041 __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
1042 {
1043         struct tape_device *device;
1044         struct tape_request *request;
1045         int rc;
1046
1047         device = (struct tape_device *) cdev->dev.driver_data;
1048         if (device == NULL) {
1049                 PRINT_ERR("could not get device structure for %s "
1050                           "in interrupt\n", cdev->dev.bus_id);
1051                 return;
1052         }
1053         request = (struct tape_request *) intparm;
1054
1055         DBF_LH(6, "__tape_do_irq(device=%p, request=%p)\n", device, request);
1056
1057         /* On special conditions irb is an error pointer */
1058         if (IS_ERR(irb)) {
1059                 /* FIXME: What to do with the request? */
1060                 switch (PTR_ERR(irb)) {
1061                         case -ETIMEDOUT:
1062                                 PRINT_WARN("(%s): Request timed out\n",
1063                                         cdev->dev.bus_id);
1064                         case -EIO:
1065                                 __tape_end_request(device, request, -EIO);
1066                                 break;
1067                         default:
1068                                 PRINT_ERR("(%s): Unexpected i/o error %li\n",
1069                                         cdev->dev.bus_id,
1070                                         PTR_ERR(irb));
1071                 }
1072                 return;
1073         }
1074
1075         /*
1076          * If the condition code is not zero and the start function bit is
1077          * still set, this is an deferred error and the last start I/O did
1078          * not succeed. At this point the condition that caused the deferred
1079          * error might still apply. So we just schedule the request to be
1080          * started later.
1081          */
1082         if (irb->scsw.cc != 0 && (irb->scsw.fctl & SCSW_FCTL_START_FUNC) &&
1083             (request->status == TAPE_REQUEST_IN_IO)) {
1084                 DBF_EVENT(3,"(%08x): deferred cc=%i, fctl=%i. restarting\n",
1085                         device->cdev_id, irb->scsw.cc, irb->scsw.fctl);
1086                 request->status = TAPE_REQUEST_QUEUED;
1087                 schedule_delayed_work(&device->tape_dnr, HZ);
1088                 return;
1089         }
1090
1091         /* May be an unsolicited irq */
1092         if(request != NULL)
1093                 request->rescnt = irb->scsw.count;
1094
1095         if (irb->scsw.dstat != 0x0c) {
1096                 /* Set the 'ONLINE' flag depending on sense byte 1 */
1097                 if(*(((__u8 *) irb->ecw) + 1) & SENSE_DRIVE_ONLINE)
1098                         device->tape_generic_status |= GMT_ONLINE(~0);
1099                 else
1100                         device->tape_generic_status &= ~GMT_ONLINE(~0);
1101
1102                 /*
1103                  * Any request that does not come back with channel end
1104                  * and device end is unusual. Log the sense data.
1105                  */
1106                 DBF_EVENT(3,"-- Tape Interrupthandler --\n");
1107                 tape_dump_sense_dbf(device, request, irb);
1108         } else {
1109                 /* Upon normal completion the device _is_ online */
1110                 device->tape_generic_status |= GMT_ONLINE(~0);
1111         }
1112         if (device->tape_state == TS_NOT_OPER) {
1113                 DBF_EVENT(6, "tape:device is not operational\n");
1114                 return;
1115         }
1116
1117         /*
1118          * Request that were canceled still come back with an interrupt.
1119          * To detect these request the state will be set to TAPE_REQUEST_DONE.
1120          */
1121         if(request != NULL && request->status == TAPE_REQUEST_DONE) {
1122                 __tape_end_request(device, request, -EIO);
1123                 return;
1124         }
1125
1126         rc = device->discipline->irq(device, request, irb);
1127         /*
1128          * rc < 0 : request finished unsuccessfully.
1129          * rc == TAPE_IO_SUCCESS: request finished successfully.
1130          * rc == TAPE_IO_PENDING: request is still running. Ignore rc.
1131          * rc == TAPE_IO_RETRY: request finished but needs another go.
1132          * rc == TAPE_IO_STOP: request needs to get terminated.
1133          */
1134         switch (rc) {
1135                 case TAPE_IO_SUCCESS:
1136                         /* Upon normal completion the device _is_ online */
1137                         device->tape_generic_status |= GMT_ONLINE(~0);
1138                         __tape_end_request(device, request, rc);
1139                         break;
1140                 case TAPE_IO_PENDING:
1141                         break;
1142                 case TAPE_IO_RETRY:
1143                         rc = __tape_start_io(device, request);
1144                         if (rc)
1145                                 __tape_end_request(device, request, rc);
1146                         break;
1147                 case TAPE_IO_STOP:
1148                         rc = __tape_cancel_io(device, request);
1149                         if (rc)
1150                                 __tape_end_request(device, request, rc);
1151                         break;
1152                 default:
1153                         if (rc > 0) {
1154                                 DBF_EVENT(6, "xunknownrc\n");
1155                                 PRINT_ERR("Invalid return code from discipline "
1156                                         "interrupt function.\n");
1157                                 __tape_end_request(device, request, -EIO);
1158                         } else {
1159                                 __tape_end_request(device, request, rc);
1160                         }
1161                         break;
1162         }
1163 }
1164
1165 /*
1166  * Tape device open function used by tape_char & tape_block frontends.
1167  */
1168 int
1169 tape_open(struct tape_device *device)
1170 {
1171         int rc;
1172
1173         spin_lock(get_ccwdev_lock(device->cdev));
1174         if (device->tape_state == TS_NOT_OPER) {
1175                 DBF_EVENT(6, "TAPE:nodev\n");
1176                 rc = -ENODEV;
1177         } else if (device->tape_state == TS_IN_USE) {
1178                 DBF_EVENT(6, "TAPE:dbusy\n");
1179                 rc = -EBUSY;
1180         } else if (device->tape_state == TS_BLKUSE) {
1181                 DBF_EVENT(6, "TAPE:dbusy\n");
1182                 rc = -EBUSY;
1183         } else if (device->discipline != NULL &&
1184                    !try_module_get(device->discipline->owner)) {
1185                 DBF_EVENT(6, "TAPE:nodisc\n");
1186                 rc = -ENODEV;
1187         } else {
1188                 tape_state_set(device, TS_IN_USE);
1189                 rc = 0;
1190         }
1191         spin_unlock(get_ccwdev_lock(device->cdev));
1192         return rc;
1193 }
1194
1195 /*
1196  * Tape device release function used by tape_char & tape_block frontends.
1197  */
1198 int
1199 tape_release(struct tape_device *device)
1200 {
1201         spin_lock(get_ccwdev_lock(device->cdev));
1202         if (device->tape_state == TS_IN_USE)
1203                 tape_state_set(device, TS_UNUSED);
1204         module_put(device->discipline->owner);
1205         spin_unlock(get_ccwdev_lock(device->cdev));
1206         return 0;
1207 }
1208
1209 /*
1210  * Execute a magnetic tape command a number of times.
1211  */
1212 int
1213 tape_mtop(struct tape_device *device, int mt_op, int mt_count)
1214 {
1215         tape_mtop_fn fn;
1216         int rc;
1217
1218         DBF_EVENT(6, "TAPE:mtio\n");
1219         DBF_EVENT(6, "TAPE:ioop: %x\n", mt_op);
1220         DBF_EVENT(6, "TAPE:arg:  %x\n", mt_count);
1221
1222         if (mt_op < 0 || mt_op >= TAPE_NR_MTOPS)
1223                 return -EINVAL;
1224         fn = device->discipline->mtop_array[mt_op];
1225         if (fn == NULL)
1226                 return -EINVAL;
1227
1228         /* We assume that the backends can handle count up to 500. */
1229         if (mt_op == MTBSR  || mt_op == MTFSR  || mt_op == MTFSF  ||
1230             mt_op == MTBSF  || mt_op == MTFSFM || mt_op == MTBSFM) {
1231                 rc = 0;
1232                 for (; mt_count > 500; mt_count -= 500)
1233                         if ((rc = fn(device, 500)) != 0)
1234                                 break;
1235                 if (rc == 0)
1236                         rc = fn(device, mt_count);
1237         } else
1238                 rc = fn(device, mt_count);
1239         return rc;
1240
1241 }
1242
1243 /*
1244  * Tape init function.
1245  */
1246 static int
1247 tape_init (void)
1248 {
1249         TAPE_DBF_AREA = debug_register ( "tape", 2, 2, 4*sizeof(long));
1250         debug_register_view(TAPE_DBF_AREA, &debug_sprintf_view);
1251 #ifdef DBF_LIKE_HELL
1252         debug_set_level(TAPE_DBF_AREA, 6);
1253 #endif
1254         DBF_EVENT(3, "tape init\n");
1255         tape_proc_init();
1256         tapechar_init ();
1257         tapeblock_init ();
1258         return 0;
1259 }
1260
1261 /*
1262  * Tape exit function.
1263  */
1264 static void
1265 tape_exit(void)
1266 {
1267         DBF_EVENT(6, "tape exit\n");
1268
1269         /* Get rid of the frontends */
1270         tapechar_exit();
1271         tapeblock_exit();
1272         tape_proc_cleanup();
1273         debug_unregister (TAPE_DBF_AREA);
1274 }
1275
1276 MODULE_AUTHOR("(C) 2001 IBM Deutschland Entwicklung GmbH by Carsten Otte and "
1277               "Michael Holzheu (cotte@de.ibm.com,holzheu@de.ibm.com)");
1278 MODULE_DESCRIPTION("Linux on zSeries channel attached tape device driver");
1279 MODULE_LICENSE("GPL");
1280
1281 module_init(tape_init);
1282 module_exit(tape_exit);
1283
1284 EXPORT_SYMBOL(tape_generic_remove);
1285 EXPORT_SYMBOL(tape_generic_probe);
1286 EXPORT_SYMBOL(tape_generic_online);
1287 EXPORT_SYMBOL(tape_generic_offline);
1288 EXPORT_SYMBOL(tape_put_device);
1289 EXPORT_SYMBOL(tape_get_device_reference);
1290 EXPORT_SYMBOL(tape_state_verbose);
1291 EXPORT_SYMBOL(tape_op_verbose);
1292 EXPORT_SYMBOL(tape_state_set);
1293 EXPORT_SYMBOL(tape_med_state_set);
1294 EXPORT_SYMBOL(tape_alloc_request);
1295 EXPORT_SYMBOL(tape_free_request);
1296 EXPORT_SYMBOL(tape_dump_sense);
1297 EXPORT_SYMBOL(tape_dump_sense_dbf);
1298 EXPORT_SYMBOL(tape_do_io);
1299 EXPORT_SYMBOL(tape_do_io_async);
1300 EXPORT_SYMBOL(tape_do_io_interruptible);
1301 EXPORT_SYMBOL(tape_cancel_io);
1302 EXPORT_SYMBOL(tape_mtop);