firewire: improve refcounting of fw_card
[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.
163          */
164         spin_lock_irqsave(&card->lock, flags);
165         device->node->data = NULL;
166         spin_unlock_irqrestore(&card->lock, flags);
167
168         fw_node_put(device->node);
169         kfree(device->config_rom);
170         kfree(device);
171         fw_card_put(card);
172 }
173
174 int fw_device_enable_phys_dma(struct fw_device *device)
175 {
176         int generation = device->generation;
177
178         /* device->node_id, accessed below, must not be older than generation */
179         smp_rmb();
180
181         return device->card->driver->enable_phys_dma(device->card,
182                                                      device->node_id,
183                                                      generation);
184 }
185 EXPORT_SYMBOL(fw_device_enable_phys_dma);
186
187 struct config_rom_attribute {
188         struct device_attribute attr;
189         u32 key;
190 };
191
192 static ssize_t
193 show_immediate(struct device *dev, struct device_attribute *dattr, char *buf)
194 {
195         struct config_rom_attribute *attr =
196                 container_of(dattr, struct config_rom_attribute, attr);
197         struct fw_csr_iterator ci;
198         u32 *dir;
199         int key, value, ret = -ENOENT;
200
201         down_read(&fw_device_rwsem);
202
203         if (is_fw_unit(dev))
204                 dir = fw_unit(dev)->directory;
205         else
206                 dir = fw_device(dev)->config_rom + 5;
207
208         fw_csr_iterator_init(&ci, dir);
209         while (fw_csr_iterator_next(&ci, &key, &value))
210                 if (attr->key == key) {
211                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
212                                        "0x%06x\n", value);
213                         break;
214                 }
215
216         up_read(&fw_device_rwsem);
217
218         return ret;
219 }
220
221 #define IMMEDIATE_ATTR(name, key)                               \
222         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
223
224 static ssize_t
225 show_text_leaf(struct device *dev, struct device_attribute *dattr, char *buf)
226 {
227         struct config_rom_attribute *attr =
228                 container_of(dattr, struct config_rom_attribute, attr);
229         struct fw_csr_iterator ci;
230         u32 *dir, *block = NULL, *p, *end;
231         int length, key, value, last_key = 0, ret = -ENOENT;
232         char *b;
233
234         down_read(&fw_device_rwsem);
235
236         if (is_fw_unit(dev))
237                 dir = fw_unit(dev)->directory;
238         else
239                 dir = fw_device(dev)->config_rom + 5;
240
241         fw_csr_iterator_init(&ci, dir);
242         while (fw_csr_iterator_next(&ci, &key, &value)) {
243                 if (attr->key == last_key &&
244                     key == (CSR_DESCRIPTOR | CSR_LEAF))
245                         block = ci.p - 1 + value;
246                 last_key = key;
247         }
248
249         if (block == NULL)
250                 goto out;
251
252         length = min(block[0] >> 16, 256U);
253         if (length < 3)
254                 goto out;
255
256         if (block[1] != 0 || block[2] != 0)
257                 /* Unknown encoding. */
258                 goto out;
259
260         if (buf == NULL) {
261                 ret = length * 4;
262                 goto out;
263         }
264
265         b = buf;
266         end = &block[length + 1];
267         for (p = &block[3]; p < end; p++, b += 4)
268                 * (u32 *) b = (__force u32) __cpu_to_be32(*p);
269
270         /* Strip trailing whitespace and add newline. */
271         while (b--, (isspace(*b) || *b == '\0') && b > buf);
272         strcpy(b + 1, "\n");
273         ret = b + 2 - buf;
274  out:
275         up_read(&fw_device_rwsem);
276
277         return ret;
278 }
279
280 #define TEXT_LEAF_ATTR(name, key)                               \
281         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
282
283 static struct config_rom_attribute config_rom_attributes[] = {
284         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
285         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
286         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
287         IMMEDIATE_ATTR(version, CSR_VERSION),
288         IMMEDIATE_ATTR(model, CSR_MODEL),
289         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
290         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
291         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
292 };
293
294 static void
295 init_fw_attribute_group(struct device *dev,
296                         struct device_attribute *attrs,
297                         struct fw_attribute_group *group)
298 {
299         struct device_attribute *attr;
300         int i, j;
301
302         for (j = 0; attrs[j].attr.name != NULL; j++)
303                 group->attrs[j] = &attrs[j].attr;
304
305         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
306                 attr = &config_rom_attributes[i].attr;
307                 if (attr->show(dev, attr, NULL) < 0)
308                         continue;
309                 group->attrs[j++] = &attr->attr;
310         }
311
312         BUG_ON(j >= ARRAY_SIZE(group->attrs));
313         group->attrs[j++] = NULL;
314         group->groups[0] = &group->group;
315         group->groups[1] = NULL;
316         group->group.attrs = group->attrs;
317         dev->groups = group->groups;
318 }
319
320 static ssize_t
321 modalias_show(struct device *dev,
322               struct device_attribute *attr, char *buf)
323 {
324         struct fw_unit *unit = fw_unit(dev);
325         int length;
326
327         length = get_modalias(unit, buf, PAGE_SIZE);
328         strcpy(buf + length, "\n");
329
330         return length + 1;
331 }
332
333 static ssize_t
334 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
351 config_rom_show(struct device *dev, 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
365 guid_show(struct device *dev, 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
385 read_rom(struct fw_device *device, 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 static void fw_device_shutdown(struct work_struct *work)
637 {
638         struct fw_device *device =
639                 container_of(work, struct fw_device, work.work);
640         int minor = MINOR(device->device.devt);
641
642         fw_device_cdev_remove(device);
643         device_for_each_child(&device->device, NULL, shutdown_unit);
644         device_unregister(&device->device);
645
646         down_write(&fw_device_rwsem);
647         idr_remove(&fw_device_idr, minor);
648         up_write(&fw_device_rwsem);
649         fw_device_put(device);
650 }
651
652 static struct device_type fw_device_type = {
653         .release        = fw_device_release,
654 };
655
656 /*
657  * These defines control the retry behavior for reading the config
658  * rom.  It shouldn't be necessary to tweak these; if the device
659  * doesn't respond to a config rom read within 10 seconds, it's not
660  * going to respond at all.  As for the initial delay, a lot of
661  * devices will be able to respond within half a second after bus
662  * reset.  On the other hand, it's not really worth being more
663  * aggressive than that, since it scales pretty well; if 10 devices
664  * are plugged in, they're all getting read within one second.
665  */
666
667 #define MAX_RETRIES     10
668 #define RETRY_DELAY     (3 * HZ)
669 #define INITIAL_DELAY   (HZ / 2)
670
671 static void fw_device_init(struct work_struct *work)
672 {
673         struct fw_device *device =
674                 container_of(work, struct fw_device, work.work);
675         int minor, err;
676
677         /*
678          * All failure paths here set node->data to NULL, so that we
679          * don't try to do device_for_each_child() on a kfree()'d
680          * device.
681          */
682
683         if (read_bus_info_block(device, device->generation) < 0) {
684                 if (device->config_rom_retries < MAX_RETRIES &&
685                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
686                         device->config_rom_retries++;
687                         schedule_delayed_work(&device->work, RETRY_DELAY);
688                 } else {
689                         fw_notify("giving up on config rom for node id %x\n",
690                                   device->node_id);
691                         if (device->node == device->card->root_node)
692                                 fw_schedule_bm_work(device->card, 0);
693                         fw_device_release(&device->device);
694                 }
695                 return;
696         }
697
698         err = -ENOMEM;
699
700         fw_device_get(device);
701         down_write(&fw_device_rwsem);
702         if (idr_pre_get(&fw_device_idr, GFP_KERNEL))
703                 err = idr_get_new(&fw_device_idr, device, &minor);
704         up_write(&fw_device_rwsem);
705
706         if (err < 0)
707                 goto error;
708
709         device->device.bus = &fw_bus_type;
710         device->device.type = &fw_device_type;
711         device->device.parent = device->card->device;
712         device->device.devt = MKDEV(fw_cdev_major, minor);
713         dev_set_name(&device->device, "fw%d", minor);
714
715         init_fw_attribute_group(&device->device,
716                                 fw_device_attributes,
717                                 &device->attribute_group);
718         if (device_add(&device->device)) {
719                 fw_error("Failed to add device.\n");
720                 goto error_with_cdev;
721         }
722
723         create_units(device);
724
725         /*
726          * Transition the device to running state.  If it got pulled
727          * out from under us while we did the intialization work, we
728          * have to shut down the device again here.  Normally, though,
729          * fw_node_event will be responsible for shutting it down when
730          * necessary.  We have to use the atomic cmpxchg here to avoid
731          * racing with the FW_NODE_DESTROYED case in
732          * fw_node_event().
733          */
734         if (atomic_cmpxchg(&device->state,
735                     FW_DEVICE_INITIALIZING,
736                     FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN) {
737                 fw_device_shutdown(work);
738         } else {
739                 if (device->config_rom_retries)
740                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
741                                   "%d config ROM retries\n",
742                                   dev_name(&device->device),
743                                   device->config_rom[3], device->config_rom[4],
744                                   1 << device->max_speed,
745                                   device->config_rom_retries);
746                 else
747                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
748                                   dev_name(&device->device),
749                                   device->config_rom[3], device->config_rom[4],
750                                   1 << device->max_speed);
751                 device->config_rom_retries = 0;
752         }
753
754         /*
755          * Reschedule the IRM work if we just finished reading the
756          * root node config rom.  If this races with a bus reset we
757          * just end up running the IRM work a couple of extra times -
758          * pretty harmless.
759          */
760         if (device->node == device->card->root_node)
761                 fw_schedule_bm_work(device->card, 0);
762
763         return;
764
765  error_with_cdev:
766         down_write(&fw_device_rwsem);
767         idr_remove(&fw_device_idr, minor);
768         up_write(&fw_device_rwsem);
769  error:
770         fw_device_put(device);          /* fw_device_idr's reference */
771
772         put_device(&device->device);    /* our reference */
773 }
774
775 static int update_unit(struct device *dev, void *data)
776 {
777         struct fw_unit *unit = fw_unit(dev);
778         struct fw_driver *driver = (struct fw_driver *)dev->driver;
779
780         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
781                 down(&dev->sem);
782                 driver->update(unit);
783                 up(&dev->sem);
784         }
785
786         return 0;
787 }
788
789 static void fw_device_update(struct work_struct *work)
790 {
791         struct fw_device *device =
792                 container_of(work, struct fw_device, work.work);
793
794         fw_device_cdev_update(device);
795         device_for_each_child(&device->device, NULL, update_unit);
796 }
797
798 enum {
799         REREAD_BIB_ERROR,
800         REREAD_BIB_GONE,
801         REREAD_BIB_UNCHANGED,
802         REREAD_BIB_CHANGED,
803 };
804
805 /* Reread and compare bus info block and header of root directory */
806 static int reread_bus_info_block(struct fw_device *device, int generation)
807 {
808         u32 q;
809         int i;
810
811         for (i = 0; i < 6; i++) {
812                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
813                         return REREAD_BIB_ERROR;
814
815                 if (i == 0 && q == 0)
816                         return REREAD_BIB_GONE;
817
818                 if (i > device->config_rom_length || q != device->config_rom[i])
819                         return REREAD_BIB_CHANGED;
820         }
821
822         return REREAD_BIB_UNCHANGED;
823 }
824
825 static void fw_device_refresh(struct work_struct *work)
826 {
827         struct fw_device *device =
828                 container_of(work, struct fw_device, work.work);
829         struct fw_card *card = device->card;
830         int node_id = device->node_id;
831
832         switch (reread_bus_info_block(device, device->generation)) {
833         case REREAD_BIB_ERROR:
834                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
835                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
836                         device->config_rom_retries++;
837                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
838
839                         return;
840                 }
841                 goto give_up;
842
843         case REREAD_BIB_GONE:
844                 goto gone;
845
846         case REREAD_BIB_UNCHANGED:
847                 if (atomic_cmpxchg(&device->state,
848                             FW_DEVICE_INITIALIZING,
849                             FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
850                         goto gone;
851
852                 fw_device_update(work);
853                 device->config_rom_retries = 0;
854                 goto out;
855
856         case REREAD_BIB_CHANGED:
857                 break;
858         }
859
860         /*
861          * Something changed.  We keep things simple and don't investigate
862          * further.  We just destroy all previous units and create new ones.
863          */
864         device_for_each_child(&device->device, NULL, shutdown_unit);
865
866         if (read_bus_info_block(device, device->generation) < 0) {
867                 if (device->config_rom_retries < MAX_RETRIES &&
868                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
869                         device->config_rom_retries++;
870                         schedule_delayed_work(&device->work, RETRY_DELAY);
871
872                         return;
873                 }
874                 goto give_up;
875         }
876
877         create_units(device);
878
879         if (atomic_cmpxchg(&device->state,
880                     FW_DEVICE_INITIALIZING,
881                     FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
882                 goto gone;
883
884         fw_notify("refreshed device %s\n", dev_name(&device->device));
885         device->config_rom_retries = 0;
886         goto out;
887
888  give_up:
889         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
890  gone:
891         atomic_set(&device->state, FW_DEVICE_SHUTDOWN);
892         fw_device_shutdown(work);
893  out:
894         if (node_id == card->root_node->node_id)
895                 fw_schedule_bm_work(card, 0);
896 }
897
898 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
899 {
900         struct fw_device *device;
901
902         switch (event) {
903         case FW_NODE_CREATED:
904         case FW_NODE_LINK_ON:
905                 if (!node->link_on)
906                         break;
907  create:
908                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
909                 if (device == NULL)
910                         break;
911
912                 /*
913                  * Do minimal intialization of the device here, the
914                  * rest will happen in fw_device_init().  We need the
915                  * card and node so we can read the config rom and we
916                  * need to do device_initialize() now so
917                  * device_for_each_child() in FW_NODE_UPDATED is
918                  * doesn't freak out.
919                  */
920                 device_initialize(&device->device);
921                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
922                 device->card = fw_card_get(card);
923                 device->node = fw_node_get(node);
924                 device->node_id = node->node_id;
925                 device->generation = card->generation;
926                 INIT_LIST_HEAD(&device->client_list);
927
928                 /*
929                  * Set the node data to point back to this device so
930                  * FW_NODE_UPDATED callbacks can update the node_id
931                  * and generation for the device.
932                  */
933                 node->data = device;
934
935                 /*
936                  * Many devices are slow to respond after bus resets,
937                  * especially if they are bus powered and go through
938                  * power-up after getting plugged in.  We schedule the
939                  * first config rom scan half a second after bus reset.
940                  */
941                 INIT_DELAYED_WORK(&device->work, fw_device_init);
942                 schedule_delayed_work(&device->work, INITIAL_DELAY);
943                 break;
944
945         case FW_NODE_INITIATED_RESET:
946                 device = node->data;
947                 if (device == NULL)
948                         goto create;
949
950                 device->node_id = node->node_id;
951                 smp_wmb();  /* update node_id before generation */
952                 device->generation = card->generation;
953                 if (atomic_cmpxchg(&device->state,
954                             FW_DEVICE_RUNNING,
955                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
956                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
957                         schedule_delayed_work(&device->work,
958                                 node == card->local_node ? 0 : INITIAL_DELAY);
959                 }
960                 break;
961
962         case FW_NODE_UPDATED:
963                 if (!node->link_on || node->data == NULL)
964                         break;
965
966                 device = node->data;
967                 device->node_id = node->node_id;
968                 smp_wmb();  /* update node_id before generation */
969                 device->generation = card->generation;
970                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
971                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
972                         schedule_delayed_work(&device->work, 0);
973                 }
974                 break;
975
976         case FW_NODE_DESTROYED:
977         case FW_NODE_LINK_OFF:
978                 if (!node->data)
979                         break;
980
981                 /*
982                  * Destroy the device associated with the node.  There
983                  * are two cases here: either the device is fully
984                  * initialized (FW_DEVICE_RUNNING) or we're in the
985                  * process of reading its config rom
986                  * (FW_DEVICE_INITIALIZING).  If it is fully
987                  * initialized we can reuse device->work to schedule a
988                  * full fw_device_shutdown().  If not, there's work
989                  * scheduled to read it's config rom, and we just put
990                  * the device in shutdown state to have that code fail
991                  * to create the device.
992                  */
993                 device = node->data;
994                 if (atomic_xchg(&device->state,
995                                 FW_DEVICE_SHUTDOWN) == FW_DEVICE_RUNNING) {
996                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
997                         schedule_delayed_work(&device->work, 0);
998                 }
999                 break;
1000         }
1001 }