firewire: add minor number range check to fw_device_init()
[~shefty/rdma-dev.git] / drivers / firewire / core-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/bug.h>
22 #include <linux/ctype.h>
23 #include <linux/delay.h>
24 #include <linux/device.h>
25 #include <linux/errno.h>
26 #include <linux/firewire.h>
27 #include <linux/firewire-constants.h>
28 #include <linux/idr.h>
29 #include <linux/jiffies.h>
30 #include <linux/kobject.h>
31 #include <linux/list.h>
32 #include <linux/mod_devicetable.h>
33 #include <linux/module.h>
34 #include <linux/mutex.h>
35 #include <linux/random.h>
36 #include <linux/rwsem.h>
37 #include <linux/slab.h>
38 #include <linux/spinlock.h>
39 #include <linux/string.h>
40 #include <linux/workqueue.h>
41
42 #include <linux/atomic.h>
43 #include <asm/byteorder.h>
44
45 #include "core.h"
46
47 void fw_csr_iterator_init(struct fw_csr_iterator *ci, const u32 *p)
48 {
49         ci->p = p + 1;
50         ci->end = ci->p + (p[0] >> 16);
51 }
52 EXPORT_SYMBOL(fw_csr_iterator_init);
53
54 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
55 {
56         *key = *ci->p >> 24;
57         *value = *ci->p & 0xffffff;
58
59         return ci->p++ < ci->end;
60 }
61 EXPORT_SYMBOL(fw_csr_iterator_next);
62
63 static const u32 *search_leaf(const u32 *directory, int search_key)
64 {
65         struct fw_csr_iterator ci;
66         int last_key = 0, key, value;
67
68         fw_csr_iterator_init(&ci, directory);
69         while (fw_csr_iterator_next(&ci, &key, &value)) {
70                 if (last_key == search_key &&
71                     key == (CSR_DESCRIPTOR | CSR_LEAF))
72                         return ci.p - 1 + value;
73
74                 last_key = key;
75         }
76
77         return NULL;
78 }
79
80 static int textual_leaf_to_string(const u32 *block, char *buf, size_t size)
81 {
82         unsigned int quadlets, i;
83         char c;
84
85         if (!size || !buf)
86                 return -EINVAL;
87
88         quadlets = min(block[0] >> 16, 256U);
89         if (quadlets < 2)
90                 return -ENODATA;
91
92         if (block[1] != 0 || block[2] != 0)
93                 /* unknown language/character set */
94                 return -ENODATA;
95
96         block += 3;
97         quadlets -= 2;
98         for (i = 0; i < quadlets * 4 && i < size - 1; i++) {
99                 c = block[i / 4] >> (24 - 8 * (i % 4));
100                 if (c == '\0')
101                         break;
102                 buf[i] = c;
103         }
104         buf[i] = '\0';
105
106         return i;
107 }
108
109 /**
110  * fw_csr_string() - reads a string from the configuration ROM
111  * @directory:  e.g. root directory or unit directory
112  * @key:        the key of the preceding directory entry
113  * @buf:        where to put the string
114  * @size:       size of @buf, in bytes
115  *
116  * The string is taken from a minimal ASCII text descriptor leaf after
117  * the immediate entry with @key.  The string is zero-terminated.
118  * Returns strlen(buf) or a negative error code.
119  */
120 int fw_csr_string(const u32 *directory, int key, char *buf, size_t size)
121 {
122         const u32 *leaf = search_leaf(directory, key);
123         if (!leaf)
124                 return -ENOENT;
125
126         return textual_leaf_to_string(leaf, buf, size);
127 }
128 EXPORT_SYMBOL(fw_csr_string);
129
130 static void get_ids(const u32 *directory, int *id)
131 {
132         struct fw_csr_iterator ci;
133         int key, value;
134
135         fw_csr_iterator_init(&ci, directory);
136         while (fw_csr_iterator_next(&ci, &key, &value)) {
137                 switch (key) {
138                 case CSR_VENDOR:        id[0] = value; break;
139                 case CSR_MODEL:         id[1] = value; break;
140                 case CSR_SPECIFIER_ID:  id[2] = value; break;
141                 case CSR_VERSION:       id[3] = value; break;
142                 }
143         }
144 }
145
146 static void get_modalias_ids(struct fw_unit *unit, int *id)
147 {
148         get_ids(&fw_parent_device(unit)->config_rom[5], id);
149         get_ids(unit->directory, id);
150 }
151
152 static bool match_ids(const struct ieee1394_device_id *id_table, int *id)
153 {
154         int match = 0;
155
156         if (id[0] == id_table->vendor_id)
157                 match |= IEEE1394_MATCH_VENDOR_ID;
158         if (id[1] == id_table->model_id)
159                 match |= IEEE1394_MATCH_MODEL_ID;
160         if (id[2] == id_table->specifier_id)
161                 match |= IEEE1394_MATCH_SPECIFIER_ID;
162         if (id[3] == id_table->version)
163                 match |= IEEE1394_MATCH_VERSION;
164
165         return (match & id_table->match_flags) == id_table->match_flags;
166 }
167
168 static bool is_fw_unit(struct device *dev);
169
170 static int fw_unit_match(struct device *dev, struct device_driver *drv)
171 {
172         const struct ieee1394_device_id *id_table =
173                         container_of(drv, struct fw_driver, driver)->id_table;
174         int id[] = {0, 0, 0, 0};
175
176         /* We only allow binding to fw_units. */
177         if (!is_fw_unit(dev))
178                 return 0;
179
180         get_modalias_ids(fw_unit(dev), id);
181
182         for (; id_table->match_flags != 0; id_table++)
183                 if (match_ids(id_table, id))
184                         return 1;
185
186         return 0;
187 }
188
189 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
190 {
191         int id[] = {0, 0, 0, 0};
192
193         get_modalias_ids(unit, id);
194
195         return snprintf(buffer, buffer_size,
196                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
197                         id[0], id[1], id[2], id[3]);
198 }
199
200 static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
201 {
202         struct fw_unit *unit = fw_unit(dev);
203         char modalias[64];
204
205         get_modalias(unit, modalias, sizeof(modalias));
206
207         if (add_uevent_var(env, "MODALIAS=%s", modalias))
208                 return -ENOMEM;
209
210         return 0;
211 }
212
213 struct bus_type fw_bus_type = {
214         .name = "firewire",
215         .match = fw_unit_match,
216 };
217 EXPORT_SYMBOL(fw_bus_type);
218
219 int fw_device_enable_phys_dma(struct fw_device *device)
220 {
221         int generation = device->generation;
222
223         /* device->node_id, accessed below, must not be older than generation */
224         smp_rmb();
225
226         return device->card->driver->enable_phys_dma(device->card,
227                                                      device->node_id,
228                                                      generation);
229 }
230 EXPORT_SYMBOL(fw_device_enable_phys_dma);
231
232 struct config_rom_attribute {
233         struct device_attribute attr;
234         u32 key;
235 };
236
237 static ssize_t show_immediate(struct device *dev,
238                               struct device_attribute *dattr, char *buf)
239 {
240         struct config_rom_attribute *attr =
241                 container_of(dattr, struct config_rom_attribute, attr);
242         struct fw_csr_iterator ci;
243         const u32 *dir;
244         int key, value, ret = -ENOENT;
245
246         down_read(&fw_device_rwsem);
247
248         if (is_fw_unit(dev))
249                 dir = fw_unit(dev)->directory;
250         else
251                 dir = fw_device(dev)->config_rom + 5;
252
253         fw_csr_iterator_init(&ci, dir);
254         while (fw_csr_iterator_next(&ci, &key, &value))
255                 if (attr->key == key) {
256                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
257                                        "0x%06x\n", value);
258                         break;
259                 }
260
261         up_read(&fw_device_rwsem);
262
263         return ret;
264 }
265
266 #define IMMEDIATE_ATTR(name, key)                               \
267         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
268
269 static ssize_t show_text_leaf(struct device *dev,
270                               struct device_attribute *dattr, char *buf)
271 {
272         struct config_rom_attribute *attr =
273                 container_of(dattr, struct config_rom_attribute, attr);
274         const u32 *dir;
275         size_t bufsize;
276         char dummy_buf[2];
277         int ret;
278
279         down_read(&fw_device_rwsem);
280
281         if (is_fw_unit(dev))
282                 dir = fw_unit(dev)->directory;
283         else
284                 dir = fw_device(dev)->config_rom + 5;
285
286         if (buf) {
287                 bufsize = PAGE_SIZE - 1;
288         } else {
289                 buf = dummy_buf;
290                 bufsize = 1;
291         }
292
293         ret = fw_csr_string(dir, attr->key, buf, bufsize);
294
295         if (ret >= 0) {
296                 /* Strip trailing whitespace and add newline. */
297                 while (ret > 0 && isspace(buf[ret - 1]))
298                         ret--;
299                 strcpy(buf + ret, "\n");
300                 ret++;
301         }
302
303         up_read(&fw_device_rwsem);
304
305         return ret;
306 }
307
308 #define TEXT_LEAF_ATTR(name, key)                               \
309         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
310
311 static struct config_rom_attribute config_rom_attributes[] = {
312         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
313         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
314         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
315         IMMEDIATE_ATTR(version, CSR_VERSION),
316         IMMEDIATE_ATTR(model, CSR_MODEL),
317         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
318         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
319         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
320 };
321
322 static void init_fw_attribute_group(struct device *dev,
323                                     struct device_attribute *attrs,
324                                     struct fw_attribute_group *group)
325 {
326         struct device_attribute *attr;
327         int i, j;
328
329         for (j = 0; attrs[j].attr.name != NULL; j++)
330                 group->attrs[j] = &attrs[j].attr;
331
332         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
333                 attr = &config_rom_attributes[i].attr;
334                 if (attr->show(dev, attr, NULL) < 0)
335                         continue;
336                 group->attrs[j++] = &attr->attr;
337         }
338
339         group->attrs[j] = NULL;
340         group->groups[0] = &group->group;
341         group->groups[1] = NULL;
342         group->group.attrs = group->attrs;
343         dev->groups = (const struct attribute_group **) group->groups;
344 }
345
346 static ssize_t modalias_show(struct device *dev,
347                              struct device_attribute *attr, char *buf)
348 {
349         struct fw_unit *unit = fw_unit(dev);
350         int length;
351
352         length = get_modalias(unit, buf, PAGE_SIZE);
353         strcpy(buf + length, "\n");
354
355         return length + 1;
356 }
357
358 static ssize_t rom_index_show(struct device *dev,
359                               struct device_attribute *attr, char *buf)
360 {
361         struct fw_device *device = fw_device(dev->parent);
362         struct fw_unit *unit = fw_unit(dev);
363
364         return snprintf(buf, PAGE_SIZE, "%d\n",
365                         (int)(unit->directory - device->config_rom));
366 }
367
368 static struct device_attribute fw_unit_attributes[] = {
369         __ATTR_RO(modalias),
370         __ATTR_RO(rom_index),
371         __ATTR_NULL,
372 };
373
374 static ssize_t config_rom_show(struct device *dev,
375                                struct device_attribute *attr, char *buf)
376 {
377         struct fw_device *device = fw_device(dev);
378         size_t length;
379
380         down_read(&fw_device_rwsem);
381         length = device->config_rom_length * 4;
382         memcpy(buf, device->config_rom, length);
383         up_read(&fw_device_rwsem);
384
385         return length;
386 }
387
388 static ssize_t guid_show(struct device *dev,
389                          struct device_attribute *attr, char *buf)
390 {
391         struct fw_device *device = fw_device(dev);
392         int ret;
393
394         down_read(&fw_device_rwsem);
395         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
396                        device->config_rom[3], device->config_rom[4]);
397         up_read(&fw_device_rwsem);
398
399         return ret;
400 }
401
402 static ssize_t is_local_show(struct device *dev,
403                              struct device_attribute *attr, char *buf)
404 {
405         struct fw_device *device = fw_device(dev);
406
407         return sprintf(buf, "%u\n", device->is_local);
408 }
409
410 static int units_sprintf(char *buf, const u32 *directory)
411 {
412         struct fw_csr_iterator ci;
413         int key, value;
414         int specifier_id = 0;
415         int version = 0;
416
417         fw_csr_iterator_init(&ci, directory);
418         while (fw_csr_iterator_next(&ci, &key, &value)) {
419                 switch (key) {
420                 case CSR_SPECIFIER_ID:
421                         specifier_id = value;
422                         break;
423                 case CSR_VERSION:
424                         version = value;
425                         break;
426                 }
427         }
428
429         return sprintf(buf, "0x%06x:0x%06x ", specifier_id, version);
430 }
431
432 static ssize_t units_show(struct device *dev,
433                           struct device_attribute *attr, char *buf)
434 {
435         struct fw_device *device = fw_device(dev);
436         struct fw_csr_iterator ci;
437         int key, value, i = 0;
438
439         down_read(&fw_device_rwsem);
440         fw_csr_iterator_init(&ci, &device->config_rom[5]);
441         while (fw_csr_iterator_next(&ci, &key, &value)) {
442                 if (key != (CSR_UNIT | CSR_DIRECTORY))
443                         continue;
444                 i += units_sprintf(&buf[i], ci.p + value - 1);
445                 if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
446                         break;
447         }
448         up_read(&fw_device_rwsem);
449
450         if (i)
451                 buf[i - 1] = '\n';
452
453         return i;
454 }
455
456 static struct device_attribute fw_device_attributes[] = {
457         __ATTR_RO(config_rom),
458         __ATTR_RO(guid),
459         __ATTR_RO(is_local),
460         __ATTR_RO(units),
461         __ATTR_NULL,
462 };
463
464 static int read_rom(struct fw_device *device,
465                     int generation, int index, u32 *data)
466 {
467         u64 offset = (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4;
468         int i, rcode;
469
470         /* device->node_id, accessed below, must not be older than generation */
471         smp_rmb();
472
473         for (i = 10; i < 100; i += 10) {
474                 rcode = fw_run_transaction(device->card,
475                                 TCODE_READ_QUADLET_REQUEST, device->node_id,
476                                 generation, device->max_speed, offset, data, 4);
477                 if (rcode != RCODE_BUSY)
478                         break;
479                 msleep(i);
480         }
481         be32_to_cpus(data);
482
483         return rcode;
484 }
485
486 #define MAX_CONFIG_ROM_SIZE 256
487
488 /*
489  * Read the bus info block, perform a speed probe, and read all of the rest of
490  * the config ROM.  We do all this with a cached bus generation.  If the bus
491  * generation changes under us, read_config_rom will fail and get retried.
492  * It's better to start all over in this case because the node from which we
493  * are reading the ROM may have changed the ROM during the reset.
494  * Returns either a result code or a negative error code.
495  */
496 static int read_config_rom(struct fw_device *device, int generation)
497 {
498         struct fw_card *card = device->card;
499         const u32 *old_rom, *new_rom;
500         u32 *rom, *stack;
501         u32 sp, key;
502         int i, end, length, ret;
503
504         rom = kmalloc(sizeof(*rom) * MAX_CONFIG_ROM_SIZE +
505                       sizeof(*stack) * MAX_CONFIG_ROM_SIZE, GFP_KERNEL);
506         if (rom == NULL)
507                 return -ENOMEM;
508
509         stack = &rom[MAX_CONFIG_ROM_SIZE];
510         memset(rom, 0, sizeof(*rom) * MAX_CONFIG_ROM_SIZE);
511
512         device->max_speed = SCODE_100;
513
514         /* First read the bus info block. */
515         for (i = 0; i < 5; i++) {
516                 ret = read_rom(device, generation, i, &rom[i]);
517                 if (ret != RCODE_COMPLETE)
518                         goto out;
519                 /*
520                  * As per IEEE1212 7.2, during initialization, devices can
521                  * reply with a 0 for the first quadlet of the config
522                  * rom to indicate that they are booting (for example,
523                  * if the firmware is on the disk of a external
524                  * harddisk).  In that case we just fail, and the
525                  * retry mechanism will try again later.
526                  */
527                 if (i == 0 && rom[i] == 0) {
528                         ret = RCODE_BUSY;
529                         goto out;
530                 }
531         }
532
533         device->max_speed = device->node->max_speed;
534
535         /*
536          * Determine the speed of
537          *   - devices with link speed less than PHY speed,
538          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
539          *   - all devices if there are 1394b repeaters.
540          * Note, we cannot use the bus info block's link_spd as starting point
541          * because some buggy firmwares set it lower than necessary and because
542          * 1394-1995 nodes do not have the field.
543          */
544         if ((rom[2] & 0x7) < device->max_speed ||
545             device->max_speed == SCODE_BETA ||
546             card->beta_repeaters_present) {
547                 u32 dummy;
548
549                 /* for S1600 and S3200 */
550                 if (device->max_speed == SCODE_BETA)
551                         device->max_speed = card->link_speed;
552
553                 while (device->max_speed > SCODE_100) {
554                         if (read_rom(device, generation, 0, &dummy) ==
555                             RCODE_COMPLETE)
556                                 break;
557                         device->max_speed--;
558                 }
559         }
560
561         /*
562          * Now parse the config rom.  The config rom is a recursive
563          * directory structure so we parse it using a stack of
564          * references to the blocks that make up the structure.  We
565          * push a reference to the root directory on the stack to
566          * start things off.
567          */
568         length = i;
569         sp = 0;
570         stack[sp++] = 0xc0000005;
571         while (sp > 0) {
572                 /*
573                  * Pop the next block reference of the stack.  The
574                  * lower 24 bits is the offset into the config rom,
575                  * the upper 8 bits are the type of the reference the
576                  * block.
577                  */
578                 key = stack[--sp];
579                 i = key & 0xffffff;
580                 if (WARN_ON(i >= MAX_CONFIG_ROM_SIZE)) {
581                         ret = -ENXIO;
582                         goto out;
583                 }
584
585                 /* Read header quadlet for the block to get the length. */
586                 ret = read_rom(device, generation, i, &rom[i]);
587                 if (ret != RCODE_COMPLETE)
588                         goto out;
589                 end = i + (rom[i] >> 16) + 1;
590                 if (end > MAX_CONFIG_ROM_SIZE) {
591                         /*
592                          * This block extends outside the config ROM which is
593                          * a firmware bug.  Ignore this whole block, i.e.
594                          * simply set a fake block length of 0.
595                          */
596                         fw_err(card, "skipped invalid ROM block %x at %llx\n",
597                                rom[i],
598                                i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
599                         rom[i] = 0;
600                         end = i;
601                 }
602                 i++;
603
604                 /*
605                  * Now read in the block.  If this is a directory
606                  * block, check the entries as we read them to see if
607                  * it references another block, and push it in that case.
608                  */
609                 for (; i < end; i++) {
610                         ret = read_rom(device, generation, i, &rom[i]);
611                         if (ret != RCODE_COMPLETE)
612                                 goto out;
613
614                         if ((key >> 30) != 3 || (rom[i] >> 30) < 2)
615                                 continue;
616                         /*
617                          * Offset points outside the ROM.  May be a firmware
618                          * bug or an Extended ROM entry (IEEE 1212-2001 clause
619                          * 7.7.18).  Simply overwrite this pointer here by a
620                          * fake immediate entry so that later iterators over
621                          * the ROM don't have to check offsets all the time.
622                          */
623                         if (i + (rom[i] & 0xffffff) >= MAX_CONFIG_ROM_SIZE) {
624                                 fw_err(card,
625                                        "skipped unsupported ROM entry %x at %llx\n",
626                                        rom[i],
627                                        i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
628                                 rom[i] = 0;
629                                 continue;
630                         }
631                         stack[sp++] = i + rom[i];
632                 }
633                 if (length < i)
634                         length = i;
635         }
636
637         old_rom = device->config_rom;
638         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
639         if (new_rom == NULL) {
640                 ret = -ENOMEM;
641                 goto out;
642         }
643
644         down_write(&fw_device_rwsem);
645         device->config_rom = new_rom;
646         device->config_rom_length = length;
647         up_write(&fw_device_rwsem);
648
649         kfree(old_rom);
650         ret = RCODE_COMPLETE;
651         device->max_rec = rom[2] >> 12 & 0xf;
652         device->cmc     = rom[2] >> 30 & 1;
653         device->irmc    = rom[2] >> 31 & 1;
654  out:
655         kfree(rom);
656
657         return ret;
658 }
659
660 static void fw_unit_release(struct device *dev)
661 {
662         struct fw_unit *unit = fw_unit(dev);
663
664         fw_device_put(fw_parent_device(unit));
665         kfree(unit);
666 }
667
668 static struct device_type fw_unit_type = {
669         .uevent         = fw_unit_uevent,
670         .release        = fw_unit_release,
671 };
672
673 static bool is_fw_unit(struct device *dev)
674 {
675         return dev->type == &fw_unit_type;
676 }
677
678 static void create_units(struct fw_device *device)
679 {
680         struct fw_csr_iterator ci;
681         struct fw_unit *unit;
682         int key, value, i;
683
684         i = 0;
685         fw_csr_iterator_init(&ci, &device->config_rom[5]);
686         while (fw_csr_iterator_next(&ci, &key, &value)) {
687                 if (key != (CSR_UNIT | CSR_DIRECTORY))
688                         continue;
689
690                 /*
691                  * Get the address of the unit directory and try to
692                  * match the drivers id_tables against it.
693                  */
694                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
695                 if (unit == NULL) {
696                         fw_err(device->card, "out of memory for unit\n");
697                         continue;
698                 }
699
700                 unit->directory = ci.p + value - 1;
701                 unit->device.bus = &fw_bus_type;
702                 unit->device.type = &fw_unit_type;
703                 unit->device.parent = &device->device;
704                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
705
706                 BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
707                                 ARRAY_SIZE(fw_unit_attributes) +
708                                 ARRAY_SIZE(config_rom_attributes));
709                 init_fw_attribute_group(&unit->device,
710                                         fw_unit_attributes,
711                                         &unit->attribute_group);
712
713                 if (device_register(&unit->device) < 0)
714                         goto skip_unit;
715
716                 fw_device_get(device);
717                 continue;
718
719         skip_unit:
720                 kfree(unit);
721         }
722 }
723
724 static int shutdown_unit(struct device *device, void *data)
725 {
726         device_unregister(device);
727
728         return 0;
729 }
730
731 /*
732  * fw_device_rwsem acts as dual purpose mutex:
733  *   - serializes accesses to fw_device_idr,
734  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
735  *     fw_unit.directory, unless those accesses happen at safe occasions
736  */
737 DECLARE_RWSEM(fw_device_rwsem);
738
739 DEFINE_IDR(fw_device_idr);
740 int fw_cdev_major;
741
742 struct fw_device *fw_device_get_by_devt(dev_t devt)
743 {
744         struct fw_device *device;
745
746         down_read(&fw_device_rwsem);
747         device = idr_find(&fw_device_idr, MINOR(devt));
748         if (device)
749                 fw_device_get(device);
750         up_read(&fw_device_rwsem);
751
752         return device;
753 }
754
755 struct workqueue_struct *fw_workqueue;
756 EXPORT_SYMBOL(fw_workqueue);
757
758 static void fw_schedule_device_work(struct fw_device *device,
759                                     unsigned long delay)
760 {
761         queue_delayed_work(fw_workqueue, &device->work, delay);
762 }
763
764 /*
765  * These defines control the retry behavior for reading the config
766  * rom.  It shouldn't be necessary to tweak these; if the device
767  * doesn't respond to a config rom read within 10 seconds, it's not
768  * going to respond at all.  As for the initial delay, a lot of
769  * devices will be able to respond within half a second after bus
770  * reset.  On the other hand, it's not really worth being more
771  * aggressive than that, since it scales pretty well; if 10 devices
772  * are plugged in, they're all getting read within one second.
773  */
774
775 #define MAX_RETRIES     10
776 #define RETRY_DELAY     (3 * HZ)
777 #define INITIAL_DELAY   (HZ / 2)
778 #define SHUTDOWN_DELAY  (2 * HZ)
779
780 static void fw_device_shutdown(struct work_struct *work)
781 {
782         struct fw_device *device =
783                 container_of(work, struct fw_device, work.work);
784         int minor = MINOR(device->device.devt);
785
786         if (time_before64(get_jiffies_64(),
787                           device->card->reset_jiffies + SHUTDOWN_DELAY)
788             && !list_empty(&device->card->link)) {
789                 fw_schedule_device_work(device, SHUTDOWN_DELAY);
790                 return;
791         }
792
793         if (atomic_cmpxchg(&device->state,
794                            FW_DEVICE_GONE,
795                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
796                 return;
797
798         fw_device_cdev_remove(device);
799         device_for_each_child(&device->device, NULL, shutdown_unit);
800         device_unregister(&device->device);
801
802         down_write(&fw_device_rwsem);
803         idr_remove(&fw_device_idr, minor);
804         up_write(&fw_device_rwsem);
805
806         fw_device_put(device);
807 }
808
809 static void fw_device_release(struct device *dev)
810 {
811         struct fw_device *device = fw_device(dev);
812         struct fw_card *card = device->card;
813         unsigned long flags;
814
815         /*
816          * Take the card lock so we don't set this to NULL while a
817          * FW_NODE_UPDATED callback is being handled or while the
818          * bus manager work looks at this node.
819          */
820         spin_lock_irqsave(&card->lock, flags);
821         device->node->data = NULL;
822         spin_unlock_irqrestore(&card->lock, flags);
823
824         fw_node_put(device->node);
825         kfree(device->config_rom);
826         kfree(device);
827         fw_card_put(card);
828 }
829
830 static struct device_type fw_device_type = {
831         .release = fw_device_release,
832 };
833
834 static bool is_fw_device(struct device *dev)
835 {
836         return dev->type == &fw_device_type;
837 }
838
839 static int update_unit(struct device *dev, void *data)
840 {
841         struct fw_unit *unit = fw_unit(dev);
842         struct fw_driver *driver = (struct fw_driver *)dev->driver;
843
844         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
845                 device_lock(dev);
846                 driver->update(unit);
847                 device_unlock(dev);
848         }
849
850         return 0;
851 }
852
853 static void fw_device_update(struct work_struct *work)
854 {
855         struct fw_device *device =
856                 container_of(work, struct fw_device, work.work);
857
858         fw_device_cdev_update(device);
859         device_for_each_child(&device->device, NULL, update_unit);
860 }
861
862 /*
863  * If a device was pending for deletion because its node went away but its
864  * bus info block and root directory header matches that of a newly discovered
865  * device, revive the existing fw_device.
866  * The newly allocated fw_device becomes obsolete instead.
867  */
868 static int lookup_existing_device(struct device *dev, void *data)
869 {
870         struct fw_device *old = fw_device(dev);
871         struct fw_device *new = data;
872         struct fw_card *card = new->card;
873         int match = 0;
874
875         if (!is_fw_device(dev))
876                 return 0;
877
878         down_read(&fw_device_rwsem); /* serialize config_rom access */
879         spin_lock_irq(&card->lock);  /* serialize node access */
880
881         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
882             atomic_cmpxchg(&old->state,
883                            FW_DEVICE_GONE,
884                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
885                 struct fw_node *current_node = new->node;
886                 struct fw_node *obsolete_node = old->node;
887
888                 new->node = obsolete_node;
889                 new->node->data = new;
890                 old->node = current_node;
891                 old->node->data = old;
892
893                 old->max_speed = new->max_speed;
894                 old->node_id = current_node->node_id;
895                 smp_wmb();  /* update node_id before generation */
896                 old->generation = card->generation;
897                 old->config_rom_retries = 0;
898                 fw_notice(card, "rediscovered device %s\n", dev_name(dev));
899
900                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
901                 fw_schedule_device_work(old, 0);
902
903                 if (current_node == card->root_node)
904                         fw_schedule_bm_work(card, 0);
905
906                 match = 1;
907         }
908
909         spin_unlock_irq(&card->lock);
910         up_read(&fw_device_rwsem);
911
912         return match;
913 }
914
915 enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
916
917 static void set_broadcast_channel(struct fw_device *device, int generation)
918 {
919         struct fw_card *card = device->card;
920         __be32 data;
921         int rcode;
922
923         if (!card->broadcast_channel_allocated)
924                 return;
925
926         /*
927          * The Broadcast_Channel Valid bit is required by nodes which want to
928          * transmit on this channel.  Such transmissions are practically
929          * exclusive to IP over 1394 (RFC 2734).  IP capable nodes are required
930          * to be IRM capable and have a max_rec of 8 or more.  We use this fact
931          * to narrow down to which nodes we send Broadcast_Channel updates.
932          */
933         if (!device->irmc || device->max_rec < 8)
934                 return;
935
936         /*
937          * Some 1394-1995 nodes crash if this 1394a-2000 register is written.
938          * Perform a read test first.
939          */
940         if (device->bc_implemented == BC_UNKNOWN) {
941                 rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
942                                 device->node_id, generation, device->max_speed,
943                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
944                                 &data, 4);
945                 switch (rcode) {
946                 case RCODE_COMPLETE:
947                         if (data & cpu_to_be32(1 << 31)) {
948                                 device->bc_implemented = BC_IMPLEMENTED;
949                                 break;
950                         }
951                         /* else fall through to case address error */
952                 case RCODE_ADDRESS_ERROR:
953                         device->bc_implemented = BC_UNIMPLEMENTED;
954                 }
955         }
956
957         if (device->bc_implemented == BC_IMPLEMENTED) {
958                 data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
959                                    BROADCAST_CHANNEL_VALID);
960                 fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
961                                 device->node_id, generation, device->max_speed,
962                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
963                                 &data, 4);
964         }
965 }
966
967 int fw_device_set_broadcast_channel(struct device *dev, void *gen)
968 {
969         if (is_fw_device(dev))
970                 set_broadcast_channel(fw_device(dev), (long)gen);
971
972         return 0;
973 }
974
975 static void fw_device_init(struct work_struct *work)
976 {
977         struct fw_device *device =
978                 container_of(work, struct fw_device, work.work);
979         struct fw_card *card = device->card;
980         struct device *revived_dev;
981         int minor, ret;
982
983         /*
984          * All failure paths here set node->data to NULL, so that we
985          * don't try to do device_for_each_child() on a kfree()'d
986          * device.
987          */
988
989         ret = read_config_rom(device, device->generation);
990         if (ret != RCODE_COMPLETE) {
991                 if (device->config_rom_retries < MAX_RETRIES &&
992                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
993                         device->config_rom_retries++;
994                         fw_schedule_device_work(device, RETRY_DELAY);
995                 } else {
996                         if (device->node->link_on)
997                                 fw_notice(card, "giving up on node %x: reading config rom failed: %s\n",
998                                           device->node_id,
999                                           fw_rcode_string(ret));
1000                         if (device->node == card->root_node)
1001                                 fw_schedule_bm_work(card, 0);
1002                         fw_device_release(&device->device);
1003                 }
1004                 return;
1005         }
1006
1007         revived_dev = device_find_child(card->device,
1008                                         device, lookup_existing_device);
1009         if (revived_dev) {
1010                 put_device(revived_dev);
1011                 fw_device_release(&device->device);
1012
1013                 return;
1014         }
1015
1016         device_initialize(&device->device);
1017
1018         fw_device_get(device);
1019         down_write(&fw_device_rwsem);
1020         ret = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
1021               idr_get_new(&fw_device_idr, device, &minor) :
1022               -ENOMEM;
1023         if (minor >= 1 << MINORBITS) {
1024                 idr_remove(&fw_device_idr, minor);
1025                 minor = -ENOSPC;
1026         }
1027         up_write(&fw_device_rwsem);
1028
1029         if (ret < 0)
1030                 goto error;
1031
1032         device->device.bus = &fw_bus_type;
1033         device->device.type = &fw_device_type;
1034         device->device.parent = card->device;
1035         device->device.devt = MKDEV(fw_cdev_major, minor);
1036         dev_set_name(&device->device, "fw%d", minor);
1037
1038         BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
1039                         ARRAY_SIZE(fw_device_attributes) +
1040                         ARRAY_SIZE(config_rom_attributes));
1041         init_fw_attribute_group(&device->device,
1042                                 fw_device_attributes,
1043                                 &device->attribute_group);
1044
1045         if (device_add(&device->device)) {
1046                 fw_err(card, "failed to add device\n");
1047                 goto error_with_cdev;
1048         }
1049
1050         create_units(device);
1051
1052         /*
1053          * Transition the device to running state.  If it got pulled
1054          * out from under us while we did the intialization work, we
1055          * have to shut down the device again here.  Normally, though,
1056          * fw_node_event will be responsible for shutting it down when
1057          * necessary.  We have to use the atomic cmpxchg here to avoid
1058          * racing with the FW_NODE_DESTROYED case in
1059          * fw_node_event().
1060          */
1061         if (atomic_cmpxchg(&device->state,
1062                            FW_DEVICE_INITIALIZING,
1063                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
1064                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1065                 fw_schedule_device_work(device, SHUTDOWN_DELAY);
1066         } else {
1067                 fw_notice(card, "created device %s: GUID %08x%08x, S%d00\n",
1068                           dev_name(&device->device),
1069                           device->config_rom[3], device->config_rom[4],
1070                           1 << device->max_speed);
1071                 device->config_rom_retries = 0;
1072
1073                 set_broadcast_channel(device, device->generation);
1074
1075                 add_device_randomness(&device->config_rom[3], 8);
1076         }
1077
1078         /*
1079          * Reschedule the IRM work if we just finished reading the
1080          * root node config rom.  If this races with a bus reset we
1081          * just end up running the IRM work a couple of extra times -
1082          * pretty harmless.
1083          */
1084         if (device->node == card->root_node)
1085                 fw_schedule_bm_work(card, 0);
1086
1087         return;
1088
1089  error_with_cdev:
1090         down_write(&fw_device_rwsem);
1091         idr_remove(&fw_device_idr, minor);
1092         up_write(&fw_device_rwsem);
1093  error:
1094         fw_device_put(device);          /* fw_device_idr's reference */
1095
1096         put_device(&device->device);    /* our reference */
1097 }
1098
1099 /* Reread and compare bus info block and header of root directory */
1100 static int reread_config_rom(struct fw_device *device, int generation,
1101                              bool *changed)
1102 {
1103         u32 q;
1104         int i, rcode;
1105
1106         for (i = 0; i < 6; i++) {
1107                 rcode = read_rom(device, generation, i, &q);
1108                 if (rcode != RCODE_COMPLETE)
1109                         return rcode;
1110
1111                 if (i == 0 && q == 0)
1112                         /* inaccessible (see read_config_rom); retry later */
1113                         return RCODE_BUSY;
1114
1115                 if (q != device->config_rom[i]) {
1116                         *changed = true;
1117                         return RCODE_COMPLETE;
1118                 }
1119         }
1120
1121         *changed = false;
1122         return RCODE_COMPLETE;
1123 }
1124
1125 static void fw_device_refresh(struct work_struct *work)
1126 {
1127         struct fw_device *device =
1128                 container_of(work, struct fw_device, work.work);
1129         struct fw_card *card = device->card;
1130         int ret, node_id = device->node_id;
1131         bool changed;
1132
1133         ret = reread_config_rom(device, device->generation, &changed);
1134         if (ret != RCODE_COMPLETE)
1135                 goto failed_config_rom;
1136
1137         if (!changed) {
1138                 if (atomic_cmpxchg(&device->state,
1139                                    FW_DEVICE_INITIALIZING,
1140                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1141                         goto gone;
1142
1143                 fw_device_update(work);
1144                 device->config_rom_retries = 0;
1145                 goto out;
1146         }
1147
1148         /*
1149          * Something changed.  We keep things simple and don't investigate
1150          * further.  We just destroy all previous units and create new ones.
1151          */
1152         device_for_each_child(&device->device, NULL, shutdown_unit);
1153
1154         ret = read_config_rom(device, device->generation);
1155         if (ret != RCODE_COMPLETE)
1156                 goto failed_config_rom;
1157
1158         fw_device_cdev_update(device);
1159         create_units(device);
1160
1161         /* Userspace may want to re-read attributes. */
1162         kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1163
1164         if (atomic_cmpxchg(&device->state,
1165                            FW_DEVICE_INITIALIZING,
1166                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1167                 goto gone;
1168
1169         fw_notice(card, "refreshed device %s\n", dev_name(&device->device));
1170         device->config_rom_retries = 0;
1171         goto out;
1172
1173  failed_config_rom:
1174         if (device->config_rom_retries < MAX_RETRIES &&
1175             atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1176                 device->config_rom_retries++;
1177                 fw_schedule_device_work(device, RETRY_DELAY);
1178                 return;
1179         }
1180
1181         fw_notice(card, "giving up on refresh of device %s: %s\n",
1182                   dev_name(&device->device), fw_rcode_string(ret));
1183  gone:
1184         atomic_set(&device->state, FW_DEVICE_GONE);
1185         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1186         fw_schedule_device_work(device, SHUTDOWN_DELAY);
1187  out:
1188         if (node_id == card->root_node->node_id)
1189                 fw_schedule_bm_work(card, 0);
1190 }
1191
1192 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1193 {
1194         struct fw_device *device;
1195
1196         switch (event) {
1197         case FW_NODE_CREATED:
1198                 /*
1199                  * Attempt to scan the node, regardless whether its self ID has
1200                  * the L (link active) flag set or not.  Some broken devices
1201                  * send L=0 but have an up-and-running link; others send L=1
1202                  * without actually having a link.
1203                  */
1204  create:
1205                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
1206                 if (device == NULL)
1207                         break;
1208
1209                 /*
1210                  * Do minimal intialization of the device here, the
1211                  * rest will happen in fw_device_init().
1212                  *
1213                  * Attention:  A lot of things, even fw_device_get(),
1214                  * cannot be done before fw_device_init() finished!
1215                  * You can basically just check device->state and
1216                  * schedule work until then, but only while holding
1217                  * card->lock.
1218                  */
1219                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1220                 device->card = fw_card_get(card);
1221                 device->node = fw_node_get(node);
1222                 device->node_id = node->node_id;
1223                 device->generation = card->generation;
1224                 device->is_local = node == card->local_node;
1225                 mutex_init(&device->client_list_mutex);
1226                 INIT_LIST_HEAD(&device->client_list);
1227
1228                 /*
1229                  * Set the node data to point back to this device so
1230                  * FW_NODE_UPDATED callbacks can update the node_id
1231                  * and generation for the device.
1232                  */
1233                 node->data = device;
1234
1235                 /*
1236                  * Many devices are slow to respond after bus resets,
1237                  * especially if they are bus powered and go through
1238                  * power-up after getting plugged in.  We schedule the
1239                  * first config rom scan half a second after bus reset.
1240                  */
1241                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1242                 fw_schedule_device_work(device, INITIAL_DELAY);
1243                 break;
1244
1245         case FW_NODE_INITIATED_RESET:
1246         case FW_NODE_LINK_ON:
1247                 device = node->data;
1248                 if (device == NULL)
1249                         goto create;
1250
1251                 device->node_id = node->node_id;
1252                 smp_wmb();  /* update node_id before generation */
1253                 device->generation = card->generation;
1254                 if (atomic_cmpxchg(&device->state,
1255                             FW_DEVICE_RUNNING,
1256                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1257                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1258                         fw_schedule_device_work(device,
1259                                 device->is_local ? 0 : INITIAL_DELAY);
1260                 }
1261                 break;
1262
1263         case FW_NODE_UPDATED:
1264                 device = node->data;
1265                 if (device == NULL)
1266                         break;
1267
1268                 device->node_id = node->node_id;
1269                 smp_wmb();  /* update node_id before generation */
1270                 device->generation = card->generation;
1271                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1272                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1273                         fw_schedule_device_work(device, 0);
1274                 }
1275                 break;
1276
1277         case FW_NODE_DESTROYED:
1278         case FW_NODE_LINK_OFF:
1279                 if (!node->data)
1280                         break;
1281
1282                 /*
1283                  * Destroy the device associated with the node.  There
1284                  * are two cases here: either the device is fully
1285                  * initialized (FW_DEVICE_RUNNING) or we're in the
1286                  * process of reading its config rom
1287                  * (FW_DEVICE_INITIALIZING).  If it is fully
1288                  * initialized we can reuse device->work to schedule a
1289                  * full fw_device_shutdown().  If not, there's work
1290                  * scheduled to read it's config rom, and we just put
1291                  * the device in shutdown state to have that code fail
1292                  * to create the device.
1293                  */
1294                 device = node->data;
1295                 if (atomic_xchg(&device->state,
1296                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1297                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1298                         fw_schedule_device_work(device,
1299                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1300                 }
1301                 break;
1302         }
1303 }