Pull sn2-mmio-writes into release branch
[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         if (device->tape_state < TO_SIZE && device->tape_state >= 0)
214                 str = tape_state_verbose[device->tape_state];
215         else
216                 str = "UNKNOWN TS";
217         DBF_EVENT(4, "old ts:   %s\n", str);
218         if (device->tape_state < TO_SIZE && device->tape_state >=0 )
219                 str = tape_state_verbose[device->tape_state];
220         else
221                 str = "UNKNOWN TS";
222         DBF_EVENT(4, "%s\n", str);
223         DBF_EVENT(4, "new ts:\t\n");
224         if (newstate < TO_SIZE && newstate >= 0)
225                 str = tape_state_verbose[newstate];
226         else
227                 str = "UNKNOWN TS";
228         DBF_EVENT(4, "%s\n", str);
229         device->tape_state = newstate;
230         wake_up(&device->state_change_wq);
231 }
232
233 void
234 tape_med_state_set(struct tape_device *device, enum tape_medium_state newstate)
235 {
236         if (device->medium_state == newstate)
237                 return;
238         switch(newstate){
239         case MS_UNLOADED:
240                 device->tape_generic_status |= GMT_DR_OPEN(~0);
241                 PRINT_INFO("(%s): Tape is unloaded\n",
242                            device->cdev->dev.bus_id);
243                 break;
244         case MS_LOADED:
245                 device->tape_generic_status &= ~GMT_DR_OPEN(~0);
246                 PRINT_INFO("(%s): Tape has been mounted\n",
247                            device->cdev->dev.bus_id);
248                 break;
249         default:
250                 // print nothing
251                 break;
252         }
253         device->medium_state = newstate;
254         wake_up(&device->state_change_wq);
255 }
256
257 /*
258  * Stop running ccw. Has to be called with the device lock held.
259  */
260 static inline int
261 __tape_cancel_io(struct tape_device *device, struct tape_request *request)
262 {
263         int retries;
264         int rc;
265
266         /* Check if interrupt has already been processed */
267         if (request->callback == NULL)
268                 return 0;
269
270         rc = 0;
271         for (retries = 0; retries < 5; retries++) {
272                 rc = ccw_device_clear(device->cdev, (long) request);
273
274                 switch (rc) {
275                         case 0:
276                                 request->status = TAPE_REQUEST_DONE;
277                                 return 0;
278                         case -EBUSY:
279                                 request->status = TAPE_REQUEST_CANCEL;
280                                 schedule_work(&device->tape_dnr);
281                                 return 0;
282                         case -ENODEV:
283                                 DBF_EXCEPTION(2, "device gone, retry\n");
284                                 break;
285                         case -EIO:
286                                 DBF_EXCEPTION(2, "I/O error, retry\n");
287                                 break;
288                         default:
289                                 BUG();
290                 }
291         }
292
293         return rc;
294 }
295
296 /*
297  * Add device into the sorted list, giving it the first
298  * available minor number.
299  */
300 static int
301 tape_assign_minor(struct tape_device *device)
302 {
303         struct tape_device *tmp;
304         int minor;
305
306         minor = 0;
307         write_lock(&tape_device_lock);
308         list_for_each_entry(tmp, &tape_device_list, node) {
309                 if (minor < tmp->first_minor)
310                         break;
311                 minor += TAPE_MINORS_PER_DEV;
312         }
313         if (minor >= 256) {
314                 write_unlock(&tape_device_lock);
315                 return -ENODEV;
316         }
317         device->first_minor = minor;
318         list_add_tail(&device->node, &tmp->node);
319         write_unlock(&tape_device_lock);
320         return 0;
321 }
322
323 /* remove device from the list */
324 static void
325 tape_remove_minor(struct tape_device *device)
326 {
327         write_lock(&tape_device_lock);
328         list_del_init(&device->node);
329         device->first_minor = -1;
330         write_unlock(&tape_device_lock);
331 }
332
333 /*
334  * Set a device online.
335  *
336  * This function is called by the common I/O layer to move a device from the
337  * detected but offline into the online state.
338  * If we return an error (RC < 0) the device remains in the offline state. This
339  * can happen if the device is assigned somewhere else, for example.
340  */
341 int
342 tape_generic_online(struct tape_device *device,
343                    struct tape_discipline *discipline)
344 {
345         int rc;
346
347         DBF_LH(6, "tape_enable_device(%p, %p)\n", device, discipline);
348
349         if (device->tape_state != TS_INIT) {
350                 DBF_LH(3, "Tapestate not INIT (%d)\n", device->tape_state);
351                 return -EINVAL;
352         }
353
354         /* Let the discipline have a go at the device. */
355         device->discipline = discipline;
356         if (!try_module_get(discipline->owner)) {
357                 PRINT_ERR("Cannot get module. Module gone.\n");
358                 return -EINVAL;
359         }
360
361         rc = discipline->setup_device(device);
362         if (rc)
363                 goto out;
364         rc = tape_assign_minor(device);
365         if (rc)
366                 goto out_discipline;
367
368         rc = tapechar_setup_device(device);
369         if (rc)
370                 goto out_minor;
371         rc = tapeblock_setup_device(device);
372         if (rc)
373                 goto out_char;
374
375         tape_state_set(device, TS_UNUSED);
376
377         DBF_LH(3, "(%08x): Drive set online\n", device->cdev_id);
378
379         return 0;
380
381 out_char:
382         tapechar_cleanup_device(device);
383 out_discipline:
384         device->discipline->cleanup_device(device);
385         device->discipline = NULL;
386 out_minor:
387         tape_remove_minor(device);
388 out:
389         module_put(discipline->owner);
390         return rc;
391 }
392
393 static inline void
394 tape_cleanup_device(struct tape_device *device)
395 {
396         tapeblock_cleanup_device(device);
397         tapechar_cleanup_device(device);
398         device->discipline->cleanup_device(device);
399         module_put(device->discipline->owner);
400         tape_remove_minor(device);
401         tape_med_state_set(device, MS_UNKNOWN);
402 }
403
404 /*
405  * Set device offline.
406  *
407  * Called by the common I/O layer if the drive should set offline on user
408  * request. We may prevent this by returning an error.
409  * Manual offline is only allowed while the drive is not in use.
410  */
411 int
412 tape_generic_offline(struct tape_device *device)
413 {
414         if (!device) {
415                 PRINT_ERR("tape_generic_offline: no such device\n");
416                 return -ENODEV;
417         }
418
419         DBF_LH(3, "(%08x): tape_generic_offline(%p)\n",
420                 device->cdev_id, device);
421
422         spin_lock_irq(get_ccwdev_lock(device->cdev));
423         switch (device->tape_state) {
424                 case TS_INIT:
425                 case TS_NOT_OPER:
426                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
427                         break;
428                 case TS_UNUSED:
429                         tape_state_set(device, TS_INIT);
430                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
431                         tape_cleanup_device(device);
432                         break;
433                 default:
434                         DBF_EVENT(3, "(%08x): Set offline failed "
435                                 "- drive in use.\n",
436                                 device->cdev_id);
437                         PRINT_WARN("(%s): Set offline failed "
438                                 "- drive in use.\n",
439                                 device->cdev->dev.bus_id);
440                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
441                         return -EBUSY;
442         }
443
444         DBF_LH(3, "(%08x): Drive set offline.\n", device->cdev_id);
445         return 0;
446 }
447
448 /*
449  * Allocate memory for a new device structure.
450  */
451 static struct tape_device *
452 tape_alloc_device(void)
453 {
454         struct tape_device *device;
455
456         device = (struct tape_device *)
457                 kmalloc(sizeof(struct tape_device), GFP_KERNEL);
458         if (device == NULL) {
459                 DBF_EXCEPTION(2, "ti:no mem\n");
460                 PRINT_INFO ("can't allocate memory for "
461                             "tape info structure\n");
462                 return ERR_PTR(-ENOMEM);
463         }
464         memset(device, 0, sizeof(struct tape_device));
465         device->modeset_byte = (char *) kmalloc(1, GFP_KERNEL | GFP_DMA);
466         if (device->modeset_byte == NULL) {
467                 DBF_EXCEPTION(2, "ti:no mem\n");
468                 PRINT_INFO("can't allocate memory for modeset byte\n");
469                 kfree(device);
470                 return ERR_PTR(-ENOMEM);
471         }
472         INIT_LIST_HEAD(&device->req_queue);
473         INIT_LIST_HEAD(&device->node);
474         init_waitqueue_head(&device->state_change_wq);
475         device->tape_state = TS_INIT;
476         device->medium_state = MS_UNKNOWN;
477         *device->modeset_byte = 0;
478         device->first_minor = -1;
479         atomic_set(&device->ref_count, 1);
480         INIT_WORK(&device->tape_dnr, tape_delayed_next_request, device);
481
482         return device;
483 }
484
485 /*
486  * Get a reference to an existing device structure. This will automatically
487  * increment the reference count.
488  */
489 struct tape_device *
490 tape_get_device_reference(struct tape_device *device)
491 {
492         DBF_EVENT(4, "tape_get_device_reference(%p) = %i\n", device,
493                 atomic_inc_return(&device->ref_count));
494
495         return device;
496 }
497
498 /*
499  * Decrease the reference counter of a devices structure. If the
500  * reference counter reaches zero free the device structure.
501  * The function returns a NULL pointer to be used by the caller
502  * for clearing reference pointers.
503  */
504 struct tape_device *
505 tape_put_device(struct tape_device *device)
506 {
507         int remain;
508
509         remain = atomic_dec_return(&device->ref_count);
510         if (remain > 0) {
511                 DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, remain);
512         } else {
513                 if (remain < 0) {
514                         DBF_EVENT(4, "put device without reference\n");
515                         PRINT_ERR("put device without reference\n");
516                 } else {
517                         DBF_EVENT(4, "tape_free_device(%p)\n", device);
518                         kfree(device->modeset_byte);
519                         kfree(device);
520                 }
521         }
522
523         return NULL;                    
524 }
525
526 /*
527  * Find tape device by a device index.
528  */
529 struct tape_device *
530 tape_get_device(int devindex)
531 {
532         struct tape_device *device, *tmp;
533
534         device = ERR_PTR(-ENODEV);
535         read_lock(&tape_device_lock);
536         list_for_each_entry(tmp, &tape_device_list, node) {
537                 if (tmp->first_minor / TAPE_MINORS_PER_DEV == devindex) {
538                         device = tape_get_device_reference(tmp);
539                         break;
540                 }
541         }
542         read_unlock(&tape_device_lock);
543         return device;
544 }
545
546 /*
547  * Driverfs tape probe function.
548  */
549 int
550 tape_generic_probe(struct ccw_device *cdev)
551 {
552         struct tape_device *device;
553
554         device = tape_alloc_device();
555         if (IS_ERR(device))
556                 return -ENODEV;
557         PRINT_INFO("tape device %s found\n", cdev->dev.bus_id);
558         cdev->dev.driver_data = device;
559         device->cdev = cdev;
560         device->cdev_id = busid_to_int(cdev->dev.bus_id);
561         cdev->handler = __tape_do_irq;
562
563         ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP);
564         sysfs_create_group(&cdev->dev.kobj, &tape_attr_group);
565
566         return 0;
567 }
568
569 static inline void
570 __tape_discard_requests(struct tape_device *device)
571 {
572         struct tape_request *   request;
573         struct list_head *      l, *n;
574
575         list_for_each_safe(l, n, &device->req_queue) {
576                 request = list_entry(l, struct tape_request, list);
577                 if (request->status == TAPE_REQUEST_IN_IO)
578                         request->status = TAPE_REQUEST_DONE;
579                 list_del(&request->list);
580
581                 /* Decrease ref_count for removed request. */
582                 request->device = tape_put_device(device);
583                 request->rc = -EIO;
584                 if (request->callback != NULL)
585                         request->callback(request, request->callback_data);
586         }
587 }
588
589 /*
590  * Driverfs tape remove function.
591  *
592  * This function is called whenever the common I/O layer detects the device
593  * gone. This can happen at any time and we cannot refuse.
594  */
595 void
596 tape_generic_remove(struct ccw_device *cdev)
597 {
598         struct tape_device *    device;
599
600         device = cdev->dev.driver_data;
601         if (!device) {
602                 PRINT_ERR("No device pointer in tape_generic_remove!\n");
603                 return;
604         }
605         DBF_LH(3, "(%08x): tape_generic_remove(%p)\n", device->cdev_id, cdev);
606
607         spin_lock_irq(get_ccwdev_lock(device->cdev));
608         switch (device->tape_state) {
609                 case TS_INIT:
610                         tape_state_set(device, TS_NOT_OPER);
611                 case TS_NOT_OPER:
612                         /*
613                          * Nothing to do.
614                          */
615                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
616                         break;
617                 case TS_UNUSED:
618                         /*
619                          * Need only to release the device.
620                          */
621                         tape_state_set(device, TS_NOT_OPER);
622                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
623                         tape_cleanup_device(device);
624                         break;
625                 default:
626                         /*
627                          * There may be requests on the queue. We will not get
628                          * an interrupt for a request that was running. So we
629                          * just post them all as I/O errors.
630                          */
631                         DBF_EVENT(3, "(%08x): Drive in use vanished!\n",
632                                 device->cdev_id);
633                         PRINT_WARN("(%s): Drive in use vanished - "
634                                 "expect trouble!\n",
635                                 device->cdev->dev.bus_id);
636                         PRINT_WARN("State was %i\n", device->tape_state);
637                         tape_state_set(device, TS_NOT_OPER);
638                         __tape_discard_requests(device);
639                         spin_unlock_irq(get_ccwdev_lock(device->cdev));
640                         tape_cleanup_device(device);
641         }
642
643         if (cdev->dev.driver_data != NULL) {
644                 sysfs_remove_group(&cdev->dev.kobj, &tape_attr_group);
645                 cdev->dev.driver_data = tape_put_device(cdev->dev.driver_data);
646         }
647 }
648
649 /*
650  * Allocate a new tape ccw request
651  */
652 struct tape_request *
653 tape_alloc_request(int cplength, int datasize)
654 {
655         struct tape_request *request;
656
657         if (datasize > PAGE_SIZE || (cplength*sizeof(struct ccw1)) > PAGE_SIZE)
658                 BUG();
659
660         DBF_LH(6, "tape_alloc_request(%d, %d)\n", cplength, datasize);
661
662         request = (struct tape_request *) kmalloc(sizeof(struct tape_request),
663                                                   GFP_KERNEL);
664         if (request == NULL) {
665                 DBF_EXCEPTION(1, "cqra nomem\n");
666                 return ERR_PTR(-ENOMEM);
667         }
668         memset(request, 0, sizeof(struct tape_request));
669         /* allocate channel program */
670         if (cplength > 0) {
671                 request->cpaddr = kmalloc(cplength*sizeof(struct ccw1),
672                                           GFP_ATOMIC | GFP_DMA);
673                 if (request->cpaddr == NULL) {
674                         DBF_EXCEPTION(1, "cqra nomem\n");
675                         kfree(request);
676                         return ERR_PTR(-ENOMEM);
677                 }
678                 memset(request->cpaddr, 0, cplength*sizeof(struct ccw1));
679         }
680         /* alloc small kernel buffer */
681         if (datasize > 0) {
682                 request->cpdata = kmalloc(datasize, GFP_KERNEL | GFP_DMA);
683                 if (request->cpdata == NULL) {
684                         DBF_EXCEPTION(1, "cqra nomem\n");
685                         kfree(request->cpaddr);
686                         kfree(request);
687                         return ERR_PTR(-ENOMEM);
688                 }
689                 memset(request->cpdata, 0, datasize);
690         }
691         DBF_LH(6, "New request %p(%p/%p)\n", request, request->cpaddr,
692                 request->cpdata);
693
694         return request;
695 }
696
697 /*
698  * Free tape ccw request
699  */
700 void
701 tape_free_request (struct tape_request * request)
702 {
703         DBF_LH(6, "Free request %p\n", request);
704
705         if (request->device != NULL) {
706                 request->device = tape_put_device(request->device);
707         }
708         kfree(request->cpdata);
709         kfree(request->cpaddr);
710         kfree(request);
711 }
712
713 static inline int
714 __tape_start_io(struct tape_device *device, struct tape_request *request)
715 {
716         int rc;
717
718 #ifdef CONFIG_S390_TAPE_BLOCK
719         if (request->op == TO_BLOCK)
720                 device->discipline->check_locate(device, request);
721 #endif
722         rc = ccw_device_start(
723                 device->cdev,
724                 request->cpaddr,
725                 (unsigned long) request,
726                 0x00,
727                 request->options
728         );
729         if (rc == 0) {
730                 request->status = TAPE_REQUEST_IN_IO;
731         } else if (rc == -EBUSY) {
732                 /* The common I/O subsystem is currently busy. Retry later. */
733                 request->status = TAPE_REQUEST_QUEUED;
734                 schedule_work(&device->tape_dnr);
735                 rc = 0;
736         } else {
737                 /* Start failed. Remove request and indicate failure. */
738                 DBF_EVENT(1, "tape: start request failed with RC = %i\n", rc);
739         }
740         return rc;
741 }
742
743 static inline void
744 __tape_start_next_request(struct tape_device *device)
745 {
746         struct list_head *l, *n;
747         struct tape_request *request;
748         int rc;
749
750         DBF_LH(6, "__tape_start_next_request(%p)\n", device);
751         /*
752          * Try to start each request on request queue until one is
753          * started successful.
754          */
755         list_for_each_safe(l, n, &device->req_queue) {
756                 request = list_entry(l, struct tape_request, list);
757
758                 /*
759                  * Avoid race condition if bottom-half was triggered more than
760                  * once.
761                  */
762                 if (request->status == TAPE_REQUEST_IN_IO)
763                         return;
764
765                 /*
766                  * We wanted to cancel the request but the common I/O layer
767                  * was busy at that time. This can only happen if this
768                  * function is called by delayed_next_request.
769                  * Otherwise we start the next request on the queue.
770                  */
771                 if (request->status == TAPE_REQUEST_CANCEL) {
772                         rc = __tape_cancel_io(device, request);
773                 } else {
774                         rc = __tape_start_io(device, request);
775                 }
776                 if (rc == 0)
777                         return;
778
779                 /* Set ending status. */
780                 request->rc = rc;
781                 request->status = TAPE_REQUEST_DONE;
782
783                 /* Remove from request queue. */
784                 list_del(&request->list);
785
786                 /* Do callback. */
787                 if (request->callback != NULL)
788                         request->callback(request, request->callback_data);
789         }
790 }
791
792 static void
793 tape_delayed_next_request(void *data)
794 {
795         struct tape_device *    device;
796
797         device = (struct tape_device *) data;
798         DBF_LH(6, "tape_delayed_next_request(%p)\n", device);
799         spin_lock_irq(get_ccwdev_lock(device->cdev));
800         __tape_start_next_request(device);
801         spin_unlock_irq(get_ccwdev_lock(device->cdev));
802 }
803
804 static inline void
805 __tape_end_request(
806         struct tape_device *    device,
807         struct tape_request *   request,
808         int                     rc)
809 {
810         DBF_LH(6, "__tape_end_request(%p, %p, %i)\n", device, request, rc);
811         if (request) {
812                 request->rc = rc;
813                 request->status = TAPE_REQUEST_DONE;
814
815                 /* Remove from request queue. */
816                 list_del(&request->list);
817
818                 /* Do callback. */
819                 if (request->callback != NULL)
820                         request->callback(request, request->callback_data);
821         }
822
823         /* Start next request. */
824         if (!list_empty(&device->req_queue))
825                 __tape_start_next_request(device);
826 }
827
828 /*
829  * Write sense data to console/dbf
830  */
831 void
832 tape_dump_sense(struct tape_device* device, struct tape_request *request,
833                 struct irb *irb)
834 {
835         unsigned int *sptr;
836
837         PRINT_INFO("-------------------------------------------------\n");
838         PRINT_INFO("DSTAT : %02x  CSTAT: %02x   CPA: %04x\n",
839                    irb->scsw.dstat, irb->scsw.cstat, irb->scsw.cpa);
840         PRINT_INFO("DEVICE: %s\n", device->cdev->dev.bus_id);
841         if (request != NULL)
842                 PRINT_INFO("OP    : %s\n", tape_op_verbose[request->op]);
843
844         sptr = (unsigned int *) irb->ecw;
845         PRINT_INFO("Sense data: %08X %08X %08X %08X \n",
846                    sptr[0], sptr[1], sptr[2], sptr[3]);
847         PRINT_INFO("Sense data: %08X %08X %08X %08X \n",
848                    sptr[4], sptr[5], sptr[6], sptr[7]);
849         PRINT_INFO("--------------------------------------------------\n");
850 }
851
852 /*
853  * Write sense data to dbf
854  */
855 void
856 tape_dump_sense_dbf(struct tape_device *device, struct tape_request *request,
857                     struct irb *irb)
858 {
859         unsigned int *sptr;
860         const char* op;
861
862         if (request != NULL)
863                 op = tape_op_verbose[request->op];
864         else
865                 op = "---";
866         DBF_EVENT(3, "DSTAT : %02x   CSTAT: %02x\n",
867                   irb->scsw.dstat,irb->scsw.cstat);
868         DBF_EVENT(3, "DEVICE: %08x OP\t: %s\n", device->cdev_id, op);
869         sptr = (unsigned int *) irb->ecw;
870         DBF_EVENT(3, "%08x %08x\n", sptr[0], sptr[1]);
871         DBF_EVENT(3, "%08x %08x\n", sptr[2], sptr[3]);
872         DBF_EVENT(3, "%08x %08x\n", sptr[4], sptr[5]);
873         DBF_EVENT(3, "%08x %08x\n", sptr[6], sptr[7]);
874 }
875
876 /*
877  * I/O helper function. Adds the request to the request queue
878  * and starts it if the tape is idle. Has to be called with
879  * the device lock held.
880  */
881 static inline int
882 __tape_start_request(struct tape_device *device, struct tape_request *request)
883 {
884         int rc;
885
886         switch (request->op) {
887                 case TO_MSEN:
888                 case TO_ASSIGN:
889                 case TO_UNASSIGN:
890                 case TO_READ_ATTMSG:
891                         if (device->tape_state == TS_INIT)
892                                 break;
893                         if (device->tape_state == TS_UNUSED)
894                                 break;
895                 default:
896                         if (device->tape_state == TS_BLKUSE)
897                                 break;
898                         if (device->tape_state != TS_IN_USE)
899                                 return -ENODEV;
900         }
901
902         /* Increase use count of device for the added request. */
903         request->device = tape_get_device_reference(device);
904
905         if (list_empty(&device->req_queue)) {
906                 /* No other requests are on the queue. Start this one. */
907                 rc = __tape_start_io(device, request);
908                 if (rc)
909                         return rc;
910
911                 DBF_LH(5, "Request %p added for execution.\n", request);
912                 list_add(&request->list, &device->req_queue);
913         } else {
914                 DBF_LH(5, "Request %p add to queue.\n", request);
915                 request->status = TAPE_REQUEST_QUEUED;
916                 list_add_tail(&request->list, &device->req_queue);
917         }
918         return 0;
919 }
920
921 /*
922  * Add the request to the request queue, try to start it if the
923  * tape is idle. Return without waiting for end of i/o.
924  */
925 int
926 tape_do_io_async(struct tape_device *device, struct tape_request *request)
927 {
928         int rc;
929
930         DBF_LH(6, "tape_do_io_async(%p, %p)\n", device, request);
931
932         spin_lock_irq(get_ccwdev_lock(device->cdev));
933         /* Add request to request queue and try to start it. */
934         rc = __tape_start_request(device, request);
935         spin_unlock_irq(get_ccwdev_lock(device->cdev));
936         return rc;
937 }
938
939 /*
940  * tape_do_io/__tape_wake_up
941  * Add the request to the request queue, try to start it if the
942  * tape is idle and wait uninterruptible for its completion.
943  */
944 static void
945 __tape_wake_up(struct tape_request *request, void *data)
946 {
947         request->callback = NULL;
948         wake_up((wait_queue_head_t *) data);
949 }
950
951 int
952 tape_do_io(struct tape_device *device, struct tape_request *request)
953 {
954         wait_queue_head_t wq;
955         int rc;
956
957         init_waitqueue_head(&wq);
958         spin_lock_irq(get_ccwdev_lock(device->cdev));
959         /* Setup callback */
960         request->callback = __tape_wake_up;
961         request->callback_data = &wq;
962         /* Add request to request queue and try to start it. */
963         rc = __tape_start_request(device, request);
964         spin_unlock_irq(get_ccwdev_lock(device->cdev));
965         if (rc)
966                 return rc;
967         /* Request added to the queue. Wait for its completion. */
968         wait_event(wq, (request->callback == NULL));
969         /* Get rc from request */
970         return request->rc;
971 }
972
973 /*
974  * tape_do_io_interruptible/__tape_wake_up_interruptible
975  * Add the request to the request queue, try to start it if the
976  * tape is idle and wait uninterruptible for its completion.
977  */
978 static void
979 __tape_wake_up_interruptible(struct tape_request *request, void *data)
980 {
981         request->callback = NULL;
982         wake_up_interruptible((wait_queue_head_t *) data);
983 }
984
985 int
986 tape_do_io_interruptible(struct tape_device *device,
987                          struct tape_request *request)
988 {
989         wait_queue_head_t wq;
990         int rc;
991
992         init_waitqueue_head(&wq);
993         spin_lock_irq(get_ccwdev_lock(device->cdev));
994         /* Setup callback */
995         request->callback = __tape_wake_up_interruptible;
996         request->callback_data = &wq;
997         rc = __tape_start_request(device, request);
998         spin_unlock_irq(get_ccwdev_lock(device->cdev));
999         if (rc)
1000                 return rc;
1001         /* Request added to the queue. Wait for its completion. */
1002         rc = wait_event_interruptible(wq, (request->callback == NULL));
1003         if (rc != -ERESTARTSYS)
1004                 /* Request finished normally. */
1005                 return request->rc;
1006
1007         /* Interrupted by a signal. We have to stop the current request. */
1008         spin_lock_irq(get_ccwdev_lock(device->cdev));
1009         rc = __tape_cancel_io(device, request);
1010         spin_unlock_irq(get_ccwdev_lock(device->cdev));
1011         if (rc == 0) {
1012                 /* Wait for the interrupt that acknowledges the halt. */
1013                 do {
1014                         rc = wait_event_interruptible(
1015                                 wq,
1016                                 (request->callback == NULL)
1017                         );
1018                 } while (rc != -ERESTARTSYS);
1019
1020                 DBF_EVENT(3, "IO stopped on %08x\n", device->cdev_id);
1021                 rc = -ERESTARTSYS;
1022         }
1023         return rc;
1024 }
1025
1026 /*
1027  * Tape interrupt routine, called from the ccw_device layer
1028  */
1029 static void
1030 __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
1031 {
1032         struct tape_device *device;
1033         struct tape_request *request;
1034         int rc;
1035
1036         device = (struct tape_device *) cdev->dev.driver_data;
1037         if (device == NULL) {
1038                 PRINT_ERR("could not get device structure for %s "
1039                           "in interrupt\n", cdev->dev.bus_id);
1040                 return;
1041         }
1042         request = (struct tape_request *) intparm;
1043
1044         DBF_LH(6, "__tape_do_irq(device=%p, request=%p)\n", device, request);
1045
1046         /* On special conditions irb is an error pointer */
1047         if (IS_ERR(irb)) {
1048                 /* FIXME: What to do with the request? */
1049                 switch (PTR_ERR(irb)) {
1050                         case -ETIMEDOUT:
1051                                 PRINT_WARN("(%s): Request timed out\n",
1052                                         cdev->dev.bus_id);
1053                         case -EIO:
1054                                 __tape_end_request(device, request, -EIO);
1055                                 break;
1056                         default:
1057                                 PRINT_ERR("(%s): Unexpected i/o error %li\n",
1058                                         cdev->dev.bus_id,
1059                                         PTR_ERR(irb));
1060                 }
1061                 return;
1062         }
1063
1064         /*
1065          * If the condition code is not zero and the start function bit is
1066          * still set, this is an deferred error and the last start I/O did
1067          * not succeed. Restart the request now.
1068          */
1069         if (irb->scsw.cc != 0 && (irb->scsw.fctl & SCSW_FCTL_START_FUNC)) {
1070                 PRINT_WARN("(%s): deferred cc=%i. restaring\n",
1071                         cdev->dev.bus_id,
1072                         irb->scsw.cc);
1073                 rc = __tape_start_io(device, request);
1074                 if (rc)
1075                         __tape_end_request(device, request, rc);
1076                 return;
1077         }
1078
1079         /* May be an unsolicited irq */
1080         if(request != NULL)
1081                 request->rescnt = irb->scsw.count;
1082
1083         if (irb->scsw.dstat != 0x0c) {
1084                 /* Set the 'ONLINE' flag depending on sense byte 1 */
1085                 if(*(((__u8 *) irb->ecw) + 1) & SENSE_DRIVE_ONLINE)
1086                         device->tape_generic_status |= GMT_ONLINE(~0);
1087                 else
1088                         device->tape_generic_status &= ~GMT_ONLINE(~0);
1089
1090                 /*
1091                  * Any request that does not come back with channel end
1092                  * and device end is unusual. Log the sense data.
1093                  */
1094                 DBF_EVENT(3,"-- Tape Interrupthandler --\n");
1095                 tape_dump_sense_dbf(device, request, irb);
1096         } else {
1097                 /* Upon normal completion the device _is_ online */
1098                 device->tape_generic_status |= GMT_ONLINE(~0);
1099         }
1100         if (device->tape_state == TS_NOT_OPER) {
1101                 DBF_EVENT(6, "tape:device is not operational\n");
1102                 return;
1103         }
1104
1105         /*
1106          * Request that were canceled still come back with an interrupt.
1107          * To detect these request the state will be set to TAPE_REQUEST_DONE.
1108          */
1109         if(request != NULL && request->status == TAPE_REQUEST_DONE) {
1110                 __tape_end_request(device, request, -EIO);
1111                 return;
1112         }
1113
1114         rc = device->discipline->irq(device, request, irb);
1115         /*
1116          * rc < 0 : request finished unsuccessfully.
1117          * rc == TAPE_IO_SUCCESS: request finished successfully.
1118          * rc == TAPE_IO_PENDING: request is still running. Ignore rc.
1119          * rc == TAPE_IO_RETRY: request finished but needs another go.
1120          * rc == TAPE_IO_STOP: request needs to get terminated.
1121          */
1122         switch (rc) {
1123                 case TAPE_IO_SUCCESS:
1124                         /* Upon normal completion the device _is_ online */
1125                         device->tape_generic_status |= GMT_ONLINE(~0);
1126                         __tape_end_request(device, request, rc);
1127                         break;
1128                 case TAPE_IO_PENDING:
1129                         break;
1130                 case TAPE_IO_RETRY:
1131                         rc = __tape_start_io(device, request);
1132                         if (rc)
1133                                 __tape_end_request(device, request, rc);
1134                         break;
1135                 case TAPE_IO_STOP:
1136                         rc = __tape_cancel_io(device, request);
1137                         if (rc)
1138                                 __tape_end_request(device, request, rc);
1139                         break;
1140                 default:
1141                         if (rc > 0) {
1142                                 DBF_EVENT(6, "xunknownrc\n");
1143                                 PRINT_ERR("Invalid return code from discipline "
1144                                         "interrupt function.\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(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(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(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(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);
1285 EXPORT_SYMBOL(tape_dump_sense_dbf);
1286 EXPORT_SYMBOL(tape_do_io);
1287 EXPORT_SYMBOL(tape_do_io_async);
1288 EXPORT_SYMBOL(tape_do_io_interruptible);
1289 EXPORT_SYMBOL(tape_mtop);