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