firewire: cdev: extend transaction payload size check
[linux-2.6.git] / drivers / firewire / fw-device.c
1 /*
2  * Device probing and sysfs code.
3  *
4  * Copyright (C) 2005-2006  Kristian Hoegsberg <krh@bitplanet.net>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software Foundation,
18  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19  */
20
21 #include <linux/module.h>
22 #include <linux/wait.h>
23 #include <linux/errno.h>
24 #include <linux/kthread.h>
25 #include <linux/device.h>
26 #include <linux/delay.h>
27 #include <linux/idr.h>
28 #include <linux/jiffies.h>
29 #include <linux/string.h>
30 #include <linux/mutex.h>
31 #include <linux/rwsem.h>
32 #include <linux/semaphore.h>
33 #include <linux/spinlock.h>
34 #include <asm/system.h>
35 #include <linux/ctype.h>
36 #include "fw-transaction.h"
37 #include "fw-topology.h"
38 #include "fw-device.h"
39
40 void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
41 {
42         ci->p = p + 1;
43         ci->end = ci->p + (p[0] >> 16);
44 }
45 EXPORT_SYMBOL(fw_csr_iterator_init);
46
47 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
48 {
49         *key = *ci->p >> 24;
50         *value = *ci->p & 0xffffff;
51
52         return ci->p++ < ci->end;
53 }
54 EXPORT_SYMBOL(fw_csr_iterator_next);
55
56 static int is_fw_unit(struct device *dev);
57
58 static int match_unit_directory(u32 * directory, const struct fw_device_id *id)
59 {
60         struct fw_csr_iterator ci;
61         int key, value, match;
62
63         match = 0;
64         fw_csr_iterator_init(&ci, directory);
65         while (fw_csr_iterator_next(&ci, &key, &value)) {
66                 if (key == CSR_VENDOR && value == id->vendor)
67                         match |= FW_MATCH_VENDOR;
68                 if (key == CSR_MODEL && value == id->model)
69                         match |= FW_MATCH_MODEL;
70                 if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
71                         match |= FW_MATCH_SPECIFIER_ID;
72                 if (key == CSR_VERSION && value == id->version)
73                         match |= FW_MATCH_VERSION;
74         }
75
76         return (match & id->match_flags) == id->match_flags;
77 }
78
79 static int fw_unit_match(struct device *dev, struct device_driver *drv)
80 {
81         struct fw_unit *unit = fw_unit(dev);
82         struct fw_driver *driver = fw_driver(drv);
83         int i;
84
85         /* We only allow binding to fw_units. */
86         if (!is_fw_unit(dev))
87                 return 0;
88
89         for (i = 0; driver->id_table[i].match_flags != 0; i++) {
90                 if (match_unit_directory(unit->directory, &driver->id_table[i]))
91                         return 1;
92         }
93
94         return 0;
95 }
96
97 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
98 {
99         struct fw_device *device = fw_device(unit->device.parent);
100         struct fw_csr_iterator ci;
101
102         int key, value;
103         int vendor = 0;
104         int model = 0;
105         int specifier_id = 0;
106         int version = 0;
107
108         fw_csr_iterator_init(&ci, &device->config_rom[5]);
109         while (fw_csr_iterator_next(&ci, &key, &value)) {
110                 switch (key) {
111                 case CSR_VENDOR:
112                         vendor = value;
113                         break;
114                 case CSR_MODEL:
115                         model = value;
116                         break;
117                 }
118         }
119
120         fw_csr_iterator_init(&ci, unit->directory);
121         while (fw_csr_iterator_next(&ci, &key, &value)) {
122                 switch (key) {
123                 case CSR_SPECIFIER_ID:
124                         specifier_id = value;
125                         break;
126                 case CSR_VERSION:
127                         version = value;
128                         break;
129                 }
130         }
131
132         return snprintf(buffer, buffer_size,
133                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
134                         vendor, model, specifier_id, version);
135 }
136
137 static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
138 {
139         struct fw_unit *unit = fw_unit(dev);
140         char modalias[64];
141
142         get_modalias(unit, modalias, sizeof(modalias));
143
144         if (add_uevent_var(env, "MODALIAS=%s", modalias))
145                 return -ENOMEM;
146
147         return 0;
148 }
149
150 struct bus_type fw_bus_type = {
151         .name = "firewire",
152         .match = fw_unit_match,
153 };
154 EXPORT_SYMBOL(fw_bus_type);
155
156 static void fw_device_release(struct device *dev)
157 {
158         struct fw_device *device = fw_device(dev);
159         struct fw_card *card = device->card;
160         unsigned long flags;
161
162         /*
163          * Take the card lock so we don't set this to NULL while a
164          * FW_NODE_UPDATED callback is being handled or while the
165          * bus manager work looks at this node.
166          */
167         spin_lock_irqsave(&card->lock, flags);
168         device->node->data = NULL;
169         spin_unlock_irqrestore(&card->lock, flags);
170
171         fw_node_put(device->node);
172         kfree(device->config_rom);
173         kfree(device);
174         fw_card_put(card);
175 }
176
177 int fw_device_enable_phys_dma(struct fw_device *device)
178 {
179         int generation = device->generation;
180
181         /* device->node_id, accessed below, must not be older than generation */
182         smp_rmb();
183
184         return device->card->driver->enable_phys_dma(device->card,
185                                                      device->node_id,
186                                                      generation);
187 }
188 EXPORT_SYMBOL(fw_device_enable_phys_dma);
189
190 struct config_rom_attribute {
191         struct device_attribute attr;
192         u32 key;
193 };
194
195 static ssize_t show_immediate(struct device *dev,
196                               struct device_attribute *dattr, char *buf)
197 {
198         struct config_rom_attribute *attr =
199                 container_of(dattr, struct config_rom_attribute, attr);
200         struct fw_csr_iterator ci;
201         u32 *dir;
202         int key, value, ret = -ENOENT;
203
204         down_read(&fw_device_rwsem);
205
206         if (is_fw_unit(dev))
207                 dir = fw_unit(dev)->directory;
208         else
209                 dir = fw_device(dev)->config_rom + 5;
210
211         fw_csr_iterator_init(&ci, dir);
212         while (fw_csr_iterator_next(&ci, &key, &value))
213                 if (attr->key == key) {
214                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
215                                        "0x%06x\n", value);
216                         break;
217                 }
218
219         up_read(&fw_device_rwsem);
220
221         return ret;
222 }
223
224 #define IMMEDIATE_ATTR(name, key)                               \
225         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
226
227 static ssize_t show_text_leaf(struct device *dev,
228                               struct device_attribute *dattr, char *buf)
229 {
230         struct config_rom_attribute *attr =
231                 container_of(dattr, struct config_rom_attribute, attr);
232         struct fw_csr_iterator ci;
233         u32 *dir, *block = NULL, *p, *end;
234         int length, key, value, last_key = 0, ret = -ENOENT;
235         char *b;
236
237         down_read(&fw_device_rwsem);
238
239         if (is_fw_unit(dev))
240                 dir = fw_unit(dev)->directory;
241         else
242                 dir = fw_device(dev)->config_rom + 5;
243
244         fw_csr_iterator_init(&ci, dir);
245         while (fw_csr_iterator_next(&ci, &key, &value)) {
246                 if (attr->key == last_key &&
247                     key == (CSR_DESCRIPTOR | CSR_LEAF))
248                         block = ci.p - 1 + value;
249                 last_key = key;
250         }
251
252         if (block == NULL)
253                 goto out;
254
255         length = min(block[0] >> 16, 256U);
256         if (length < 3)
257                 goto out;
258
259         if (block[1] != 0 || block[2] != 0)
260                 /* Unknown encoding. */
261                 goto out;
262
263         if (buf == NULL) {
264                 ret = length * 4;
265                 goto out;
266         }
267
268         b = buf;
269         end = &block[length + 1];
270         for (p = &block[3]; p < end; p++, b += 4)
271                 * (u32 *) b = (__force u32) __cpu_to_be32(*p);
272
273         /* Strip trailing whitespace and add newline. */
274         while (b--, (isspace(*b) || *b == '\0') && b > buf);
275         strcpy(b + 1, "\n");
276         ret = b + 2 - buf;
277  out:
278         up_read(&fw_device_rwsem);
279
280         return ret;
281 }
282
283 #define TEXT_LEAF_ATTR(name, key)                               \
284         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
285
286 static struct config_rom_attribute config_rom_attributes[] = {
287         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
288         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
289         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
290         IMMEDIATE_ATTR(version, CSR_VERSION),
291         IMMEDIATE_ATTR(model, CSR_MODEL),
292         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
293         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
294         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
295 };
296
297 static void init_fw_attribute_group(struct device *dev,
298                                     struct device_attribute *attrs,
299                                     struct fw_attribute_group *group)
300 {
301         struct device_attribute *attr;
302         int i, j;
303
304         for (j = 0; attrs[j].attr.name != NULL; j++)
305                 group->attrs[j] = &attrs[j].attr;
306
307         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
308                 attr = &config_rom_attributes[i].attr;
309                 if (attr->show(dev, attr, NULL) < 0)
310                         continue;
311                 group->attrs[j++] = &attr->attr;
312         }
313
314         BUG_ON(j >= ARRAY_SIZE(group->attrs));
315         group->attrs[j++] = NULL;
316         group->groups[0] = &group->group;
317         group->groups[1] = NULL;
318         group->group.attrs = group->attrs;
319         dev->groups = group->groups;
320 }
321
322 static ssize_t modalias_show(struct device *dev,
323                              struct device_attribute *attr, char *buf)
324 {
325         struct fw_unit *unit = fw_unit(dev);
326         int length;
327
328         length = get_modalias(unit, buf, PAGE_SIZE);
329         strcpy(buf + length, "\n");
330
331         return length + 1;
332 }
333
334 static ssize_t rom_index_show(struct device *dev,
335                               struct device_attribute *attr, char *buf)
336 {
337         struct fw_device *device = fw_device(dev->parent);
338         struct fw_unit *unit = fw_unit(dev);
339
340         return snprintf(buf, PAGE_SIZE, "%d\n",
341                         (int)(unit->directory - device->config_rom));
342 }
343
344 static struct device_attribute fw_unit_attributes[] = {
345         __ATTR_RO(modalias),
346         __ATTR_RO(rom_index),
347         __ATTR_NULL,
348 };
349
350 static ssize_t config_rom_show(struct device *dev,
351                                struct device_attribute *attr, char *buf)
352 {
353         struct fw_device *device = fw_device(dev);
354         size_t length;
355
356         down_read(&fw_device_rwsem);
357         length = device->config_rom_length * 4;
358         memcpy(buf, device->config_rom, length);
359         up_read(&fw_device_rwsem);
360
361         return length;
362 }
363
364 static ssize_t guid_show(struct device *dev,
365                          struct device_attribute *attr, char *buf)
366 {
367         struct fw_device *device = fw_device(dev);
368         int ret;
369
370         down_read(&fw_device_rwsem);
371         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
372                        device->config_rom[3], device->config_rom[4]);
373         up_read(&fw_device_rwsem);
374
375         return ret;
376 }
377
378 static struct device_attribute fw_device_attributes[] = {
379         __ATTR_RO(config_rom),
380         __ATTR_RO(guid),
381         __ATTR_NULL,
382 };
383
384 static int read_rom(struct fw_device *device,
385                     int generation, int index, u32 *data)
386 {
387         int rcode;
388
389         /* device->node_id, accessed below, must not be older than generation */
390         smp_rmb();
391
392         rcode = fw_run_transaction(device->card, TCODE_READ_QUADLET_REQUEST,
393                         device->node_id, generation, device->max_speed,
394                         (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4,
395                         data, 4);
396         be32_to_cpus(data);
397
398         return rcode;
399 }
400
401 #define READ_BIB_ROM_SIZE       256
402 #define READ_BIB_STACK_SIZE     16
403
404 /*
405  * Read the bus info block, perform a speed probe, and read all of the rest of
406  * the config ROM.  We do all this with a cached bus generation.  If the bus
407  * generation changes under us, read_bus_info_block will fail and get retried.
408  * It's better to start all over in this case because the node from which we
409  * are reading the ROM may have changed the ROM during the reset.
410  */
411 static int read_bus_info_block(struct fw_device *device, int generation)
412 {
413         u32 *rom, *stack, *old_rom, *new_rom;
414         u32 sp, key;
415         int i, end, length, ret = -1;
416
417         rom = kmalloc(sizeof(*rom) * READ_BIB_ROM_SIZE +
418                       sizeof(*stack) * READ_BIB_STACK_SIZE, GFP_KERNEL);
419         if (rom == NULL)
420                 return -ENOMEM;
421
422         stack = &rom[READ_BIB_ROM_SIZE];
423
424         device->max_speed = SCODE_100;
425
426         /* First read the bus info block. */
427         for (i = 0; i < 5; i++) {
428                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
429                         goto out;
430                 /*
431                  * As per IEEE1212 7.2, during power-up, devices can
432                  * reply with a 0 for the first quadlet of the config
433                  * rom to indicate that they are booting (for example,
434                  * if the firmware is on the disk of a external
435                  * harddisk).  In that case we just fail, and the
436                  * retry mechanism will try again later.
437                  */
438                 if (i == 0 && rom[i] == 0)
439                         goto out;
440         }
441
442         device->max_speed = device->node->max_speed;
443
444         /*
445          * Determine the speed of
446          *   - devices with link speed less than PHY speed,
447          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
448          *   - all devices if there are 1394b repeaters.
449          * Note, we cannot use the bus info block's link_spd as starting point
450          * because some buggy firmwares set it lower than necessary and because
451          * 1394-1995 nodes do not have the field.
452          */
453         if ((rom[2] & 0x7) < device->max_speed ||
454             device->max_speed == SCODE_BETA ||
455             device->card->beta_repeaters_present) {
456                 u32 dummy;
457
458                 /* for S1600 and S3200 */
459                 if (device->max_speed == SCODE_BETA)
460                         device->max_speed = device->card->link_speed;
461
462                 while (device->max_speed > SCODE_100) {
463                         if (read_rom(device, generation, 0, &dummy) ==
464                             RCODE_COMPLETE)
465                                 break;
466                         device->max_speed--;
467                 }
468         }
469
470         /*
471          * Now parse the config rom.  The config rom is a recursive
472          * directory structure so we parse it using a stack of
473          * references to the blocks that make up the structure.  We
474          * push a reference to the root directory on the stack to
475          * start things off.
476          */
477         length = i;
478         sp = 0;
479         stack[sp++] = 0xc0000005;
480         while (sp > 0) {
481                 /*
482                  * Pop the next block reference of the stack.  The
483                  * lower 24 bits is the offset into the config rom,
484                  * the upper 8 bits are the type of the reference the
485                  * block.
486                  */
487                 key = stack[--sp];
488                 i = key & 0xffffff;
489                 if (i >= READ_BIB_ROM_SIZE)
490                         /*
491                          * The reference points outside the standard
492                          * config rom area, something's fishy.
493                          */
494                         goto out;
495
496                 /* Read header quadlet for the block to get the length. */
497                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
498                         goto out;
499                 end = i + (rom[i] >> 16) + 1;
500                 i++;
501                 if (end > READ_BIB_ROM_SIZE)
502                         /*
503                          * This block extends outside standard config
504                          * area (and the array we're reading it
505                          * into).  That's broken, so ignore this
506                          * device.
507                          */
508                         goto out;
509
510                 /*
511                  * Now read in the block.  If this is a directory
512                  * block, check the entries as we read them to see if
513                  * it references another block, and push it in that case.
514                  */
515                 while (i < end) {
516                         if (read_rom(device, generation, i, &rom[i]) !=
517                             RCODE_COMPLETE)
518                                 goto out;
519                         if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
520                             sp < READ_BIB_STACK_SIZE)
521                                 stack[sp++] = i + rom[i];
522                         i++;
523                 }
524                 if (length < i)
525                         length = i;
526         }
527
528         old_rom = device->config_rom;
529         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
530         if (new_rom == NULL)
531                 goto out;
532
533         down_write(&fw_device_rwsem);
534         device->config_rom = new_rom;
535         device->config_rom_length = length;
536         up_write(&fw_device_rwsem);
537
538         kfree(old_rom);
539         ret = 0;
540         device->cmc = rom[2] & 1 << 30;
541  out:
542         kfree(rom);
543
544         return ret;
545 }
546
547 static void fw_unit_release(struct device *dev)
548 {
549         struct fw_unit *unit = fw_unit(dev);
550
551         kfree(unit);
552 }
553
554 static struct device_type fw_unit_type = {
555         .uevent         = fw_unit_uevent,
556         .release        = fw_unit_release,
557 };
558
559 static int is_fw_unit(struct device *dev)
560 {
561         return dev->type == &fw_unit_type;
562 }
563
564 static void create_units(struct fw_device *device)
565 {
566         struct fw_csr_iterator ci;
567         struct fw_unit *unit;
568         int key, value, i;
569
570         i = 0;
571         fw_csr_iterator_init(&ci, &device->config_rom[5]);
572         while (fw_csr_iterator_next(&ci, &key, &value)) {
573                 if (key != (CSR_UNIT | CSR_DIRECTORY))
574                         continue;
575
576                 /*
577                  * Get the address of the unit directory and try to
578                  * match the drivers id_tables against it.
579                  */
580                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
581                 if (unit == NULL) {
582                         fw_error("failed to allocate memory for unit\n");
583                         continue;
584                 }
585
586                 unit->directory = ci.p + value - 1;
587                 unit->device.bus = &fw_bus_type;
588                 unit->device.type = &fw_unit_type;
589                 unit->device.parent = &device->device;
590                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
591
592                 init_fw_attribute_group(&unit->device,
593                                         fw_unit_attributes,
594                                         &unit->attribute_group);
595                 if (device_register(&unit->device) < 0)
596                         goto skip_unit;
597
598                 continue;
599
600         skip_unit:
601                 kfree(unit);
602         }
603 }
604
605 static int shutdown_unit(struct device *device, void *data)
606 {
607         device_unregister(device);
608
609         return 0;
610 }
611
612 /*
613  * fw_device_rwsem acts as dual purpose mutex:
614  *   - serializes accesses to fw_device_idr,
615  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
616  *     fw_unit.directory, unless those accesses happen at safe occasions
617  */
618 DECLARE_RWSEM(fw_device_rwsem);
619
620 DEFINE_IDR(fw_device_idr);
621 int fw_cdev_major;
622
623 struct fw_device *fw_device_get_by_devt(dev_t devt)
624 {
625         struct fw_device *device;
626
627         down_read(&fw_device_rwsem);
628         device = idr_find(&fw_device_idr, MINOR(devt));
629         if (device)
630                 fw_device_get(device);
631         up_read(&fw_device_rwsem);
632
633         return device;
634 }
635
636 /*
637  * These defines control the retry behavior for reading the config
638  * rom.  It shouldn't be necessary to tweak these; if the device
639  * doesn't respond to a config rom read within 10 seconds, it's not
640  * going to respond at all.  As for the initial delay, a lot of
641  * devices will be able to respond within half a second after bus
642  * reset.  On the other hand, it's not really worth being more
643  * aggressive than that, since it scales pretty well; if 10 devices
644  * are plugged in, they're all getting read within one second.
645  */
646
647 #define MAX_RETRIES     10
648 #define RETRY_DELAY     (3 * HZ)
649 #define INITIAL_DELAY   (HZ / 2)
650 #define SHUTDOWN_DELAY  (2 * HZ)
651
652 static void fw_device_shutdown(struct work_struct *work)
653 {
654         struct fw_device *device =
655                 container_of(work, struct fw_device, work.work);
656         int minor = MINOR(device->device.devt);
657
658         if (time_is_after_jiffies(device->card->reset_jiffies + SHUTDOWN_DELAY)
659             && !list_empty(&device->card->link)) {
660                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
661                 return;
662         }
663
664         if (atomic_cmpxchg(&device->state,
665                            FW_DEVICE_GONE,
666                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
667                 return;
668
669         fw_device_cdev_remove(device);
670         device_for_each_child(&device->device, NULL, shutdown_unit);
671         device_unregister(&device->device);
672
673         down_write(&fw_device_rwsem);
674         idr_remove(&fw_device_idr, minor);
675         up_write(&fw_device_rwsem);
676
677         fw_device_put(device);
678 }
679
680 static struct device_type fw_device_type = {
681         .release        = fw_device_release,
682 };
683
684 static void fw_device_update(struct work_struct *work);
685
686 /*
687  * If a device was pending for deletion because its node went away but its
688  * bus info block and root directory header matches that of a newly discovered
689  * device, revive the existing fw_device.
690  * The newly allocated fw_device becomes obsolete instead.
691  */
692 static int lookup_existing_device(struct device *dev, void *data)
693 {
694         struct fw_device *old = fw_device(dev);
695         struct fw_device *new = data;
696         struct fw_card *card = new->card;
697         int match = 0;
698
699         down_read(&fw_device_rwsem); /* serialize config_rom access */
700         spin_lock_irq(&card->lock);  /* serialize node access */
701
702         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
703             atomic_cmpxchg(&old->state,
704                            FW_DEVICE_GONE,
705                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
706                 struct fw_node *current_node = new->node;
707                 struct fw_node *obsolete_node = old->node;
708
709                 new->node = obsolete_node;
710                 new->node->data = new;
711                 old->node = current_node;
712                 old->node->data = old;
713
714                 old->max_speed = new->max_speed;
715                 old->node_id = current_node->node_id;
716                 smp_wmb();  /* update node_id before generation */
717                 old->generation = card->generation;
718                 old->config_rom_retries = 0;
719                 fw_notify("rediscovered device %s\n", dev_name(dev));
720
721                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
722                 schedule_delayed_work(&old->work, 0);
723
724                 if (current_node == card->root_node)
725                         fw_schedule_bm_work(card, 0);
726
727                 match = 1;
728         }
729
730         spin_unlock_irq(&card->lock);
731         up_read(&fw_device_rwsem);
732
733         return match;
734 }
735
736 static void fw_device_init(struct work_struct *work)
737 {
738         struct fw_device *device =
739                 container_of(work, struct fw_device, work.work);
740         struct device *revived_dev;
741         int minor, err;
742
743         /*
744          * All failure paths here set node->data to NULL, so that we
745          * don't try to do device_for_each_child() on a kfree()'d
746          * device.
747          */
748
749         if (read_bus_info_block(device, device->generation) < 0) {
750                 if (device->config_rom_retries < MAX_RETRIES &&
751                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
752                         device->config_rom_retries++;
753                         schedule_delayed_work(&device->work, RETRY_DELAY);
754                 } else {
755                         fw_notify("giving up on config rom for node id %x\n",
756                                   device->node_id);
757                         if (device->node == device->card->root_node)
758                                 fw_schedule_bm_work(device->card, 0);
759                         fw_device_release(&device->device);
760                 }
761                 return;
762         }
763
764         revived_dev = device_find_child(device->card->device,
765                                         device, lookup_existing_device);
766         if (revived_dev) {
767                 put_device(revived_dev);
768                 fw_device_release(&device->device);
769
770                 return;
771         }
772
773         device_initialize(&device->device);
774
775         fw_device_get(device);
776         down_write(&fw_device_rwsem);
777         err = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
778               idr_get_new(&fw_device_idr, device, &minor) :
779               -ENOMEM;
780         up_write(&fw_device_rwsem);
781
782         if (err < 0)
783                 goto error;
784
785         device->device.bus = &fw_bus_type;
786         device->device.type = &fw_device_type;
787         device->device.parent = device->card->device;
788         device->device.devt = MKDEV(fw_cdev_major, minor);
789         dev_set_name(&device->device, "fw%d", minor);
790
791         init_fw_attribute_group(&device->device,
792                                 fw_device_attributes,
793                                 &device->attribute_group);
794         if (device_add(&device->device)) {
795                 fw_error("Failed to add device.\n");
796                 goto error_with_cdev;
797         }
798
799         create_units(device);
800
801         /*
802          * Transition the device to running state.  If it got pulled
803          * out from under us while we did the intialization work, we
804          * have to shut down the device again here.  Normally, though,
805          * fw_node_event will be responsible for shutting it down when
806          * necessary.  We have to use the atomic cmpxchg here to avoid
807          * racing with the FW_NODE_DESTROYED case in
808          * fw_node_event().
809          */
810         if (atomic_cmpxchg(&device->state,
811                            FW_DEVICE_INITIALIZING,
812                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
813                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
814                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
815         } else {
816                 if (device->config_rom_retries)
817                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
818                                   "%d config ROM retries\n",
819                                   dev_name(&device->device),
820                                   device->config_rom[3], device->config_rom[4],
821                                   1 << device->max_speed,
822                                   device->config_rom_retries);
823                 else
824                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
825                                   dev_name(&device->device),
826                                   device->config_rom[3], device->config_rom[4],
827                                   1 << device->max_speed);
828                 device->config_rom_retries = 0;
829         }
830
831         /*
832          * Reschedule the IRM work if we just finished reading the
833          * root node config rom.  If this races with a bus reset we
834          * just end up running the IRM work a couple of extra times -
835          * pretty harmless.
836          */
837         if (device->node == device->card->root_node)
838                 fw_schedule_bm_work(device->card, 0);
839
840         return;
841
842  error_with_cdev:
843         down_write(&fw_device_rwsem);
844         idr_remove(&fw_device_idr, minor);
845         up_write(&fw_device_rwsem);
846  error:
847         fw_device_put(device);          /* fw_device_idr's reference */
848
849         put_device(&device->device);    /* our reference */
850 }
851
852 static int update_unit(struct device *dev, void *data)
853 {
854         struct fw_unit *unit = fw_unit(dev);
855         struct fw_driver *driver = (struct fw_driver *)dev->driver;
856
857         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
858                 down(&dev->sem);
859                 driver->update(unit);
860                 up(&dev->sem);
861         }
862
863         return 0;
864 }
865
866 static void fw_device_update(struct work_struct *work)
867 {
868         struct fw_device *device =
869                 container_of(work, struct fw_device, work.work);
870
871         fw_device_cdev_update(device);
872         device_for_each_child(&device->device, NULL, update_unit);
873 }
874
875 enum {
876         REREAD_BIB_ERROR,
877         REREAD_BIB_GONE,
878         REREAD_BIB_UNCHANGED,
879         REREAD_BIB_CHANGED,
880 };
881
882 /* Reread and compare bus info block and header of root directory */
883 static int reread_bus_info_block(struct fw_device *device, int generation)
884 {
885         u32 q;
886         int i;
887
888         for (i = 0; i < 6; i++) {
889                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
890                         return REREAD_BIB_ERROR;
891
892                 if (i == 0 && q == 0)
893                         return REREAD_BIB_GONE;
894
895                 if (i > device->config_rom_length || q != device->config_rom[i])
896                         return REREAD_BIB_CHANGED;
897         }
898
899         return REREAD_BIB_UNCHANGED;
900 }
901
902 static void fw_device_refresh(struct work_struct *work)
903 {
904         struct fw_device *device =
905                 container_of(work, struct fw_device, work.work);
906         struct fw_card *card = device->card;
907         int node_id = device->node_id;
908
909         switch (reread_bus_info_block(device, device->generation)) {
910         case REREAD_BIB_ERROR:
911                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
912                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
913                         device->config_rom_retries++;
914                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
915
916                         return;
917                 }
918                 goto give_up;
919
920         case REREAD_BIB_GONE:
921                 goto gone;
922
923         case REREAD_BIB_UNCHANGED:
924                 if (atomic_cmpxchg(&device->state,
925                                    FW_DEVICE_INITIALIZING,
926                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
927                         goto gone;
928
929                 fw_device_update(work);
930                 device->config_rom_retries = 0;
931                 goto out;
932
933         case REREAD_BIB_CHANGED:
934                 break;
935         }
936
937         /*
938          * Something changed.  We keep things simple and don't investigate
939          * further.  We just destroy all previous units and create new ones.
940          */
941         device_for_each_child(&device->device, NULL, shutdown_unit);
942
943         if (read_bus_info_block(device, device->generation) < 0) {
944                 if (device->config_rom_retries < MAX_RETRIES &&
945                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
946                         device->config_rom_retries++;
947                         schedule_delayed_work(&device->work, RETRY_DELAY);
948
949                         return;
950                 }
951                 goto give_up;
952         }
953
954         create_units(device);
955
956         if (atomic_cmpxchg(&device->state,
957                            FW_DEVICE_INITIALIZING,
958                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
959                 goto gone;
960
961         fw_notify("refreshed device %s\n", dev_name(&device->device));
962         device->config_rom_retries = 0;
963         goto out;
964
965  give_up:
966         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
967  gone:
968         atomic_set(&device->state, FW_DEVICE_GONE);
969         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
970         schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
971  out:
972         if (node_id == card->root_node->node_id)
973                 fw_schedule_bm_work(card, 0);
974 }
975
976 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
977 {
978         struct fw_device *device;
979
980         switch (event) {
981         case FW_NODE_CREATED:
982         case FW_NODE_LINK_ON:
983                 if (!node->link_on)
984                         break;
985  create:
986                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
987                 if (device == NULL)
988                         break;
989
990                 /*
991                  * Do minimal intialization of the device here, the
992                  * rest will happen in fw_device_init().
993                  *
994                  * Attention:  A lot of things, even fw_device_get(),
995                  * cannot be done before fw_device_init() finished!
996                  * You can basically just check device->state and
997                  * schedule work until then, but only while holding
998                  * card->lock.
999                  */
1000                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1001                 device->card = fw_card_get(card);
1002                 device->node = fw_node_get(node);
1003                 device->node_id = node->node_id;
1004                 device->generation = card->generation;
1005                 mutex_init(&device->client_list_mutex);
1006                 INIT_LIST_HEAD(&device->client_list);
1007
1008                 /*
1009                  * Set the node data to point back to this device so
1010                  * FW_NODE_UPDATED callbacks can update the node_id
1011                  * and generation for the device.
1012                  */
1013                 node->data = device;
1014
1015                 /*
1016                  * Many devices are slow to respond after bus resets,
1017                  * especially if they are bus powered and go through
1018                  * power-up after getting plugged in.  We schedule the
1019                  * first config rom scan half a second after bus reset.
1020                  */
1021                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1022                 schedule_delayed_work(&device->work, INITIAL_DELAY);
1023                 break;
1024
1025         case FW_NODE_INITIATED_RESET:
1026                 device = node->data;
1027                 if (device == NULL)
1028                         goto create;
1029
1030                 device->node_id = node->node_id;
1031                 smp_wmb();  /* update node_id before generation */
1032                 device->generation = card->generation;
1033                 if (atomic_cmpxchg(&device->state,
1034                             FW_DEVICE_RUNNING,
1035                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1036                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1037                         schedule_delayed_work(&device->work,
1038                                 node == card->local_node ? 0 : INITIAL_DELAY);
1039                 }
1040                 break;
1041
1042         case FW_NODE_UPDATED:
1043                 if (!node->link_on || node->data == NULL)
1044                         break;
1045
1046                 device = node->data;
1047                 device->node_id = node->node_id;
1048                 smp_wmb();  /* update node_id before generation */
1049                 device->generation = card->generation;
1050                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1051                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1052                         schedule_delayed_work(&device->work, 0);
1053                 }
1054                 break;
1055
1056         case FW_NODE_DESTROYED:
1057         case FW_NODE_LINK_OFF:
1058                 if (!node->data)
1059                         break;
1060
1061                 /*
1062                  * Destroy the device associated with the node.  There
1063                  * are two cases here: either the device is fully
1064                  * initialized (FW_DEVICE_RUNNING) or we're in the
1065                  * process of reading its config rom
1066                  * (FW_DEVICE_INITIALIZING).  If it is fully
1067                  * initialized we can reuse device->work to schedule a
1068                  * full fw_device_shutdown().  If not, there's work
1069                  * scheduled to read it's config rom, and we just put
1070                  * the device in shutdown state to have that code fail
1071                  * to create the device.
1072                  */
1073                 device = node->data;
1074                 if (atomic_xchg(&device->state,
1075                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1076                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1077                         schedule_delayed_work(&device->work,
1078                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1079                 }
1080                 break;
1081         }
1082 }