c91d7179eb9672d4aea7fae2d68df09956e7e174
[linux-2.6.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/rwsem.h>
36 #include <linux/semaphore.h>
37 #include <linux/spinlock.h>
38 #include <linux/string.h>
39 #include <linux/workqueue.h>
40
41 #include <asm/atomic.h>
42 #include <asm/byteorder.h>
43 #include <asm/system.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 bool is_fw_unit(struct device *dev);
131
132 static int match_unit_directory(const u32 *directory, u32 match_flags,
133                                 const struct ieee1394_device_id *id)
134 {
135         struct fw_csr_iterator ci;
136         int key, value, match;
137
138         match = 0;
139         fw_csr_iterator_init(&ci, directory);
140         while (fw_csr_iterator_next(&ci, &key, &value)) {
141                 if (key == CSR_VENDOR && value == id->vendor_id)
142                         match |= IEEE1394_MATCH_VENDOR_ID;
143                 if (key == CSR_MODEL && value == id->model_id)
144                         match |= IEEE1394_MATCH_MODEL_ID;
145                 if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
146                         match |= IEEE1394_MATCH_SPECIFIER_ID;
147                 if (key == CSR_VERSION && value == id->version)
148                         match |= IEEE1394_MATCH_VERSION;
149         }
150
151         return (match & match_flags) == match_flags;
152 }
153
154 static int fw_unit_match(struct device *dev, struct device_driver *drv)
155 {
156         struct fw_unit *unit = fw_unit(dev);
157         struct fw_device *device;
158         const struct ieee1394_device_id *id;
159
160         /* We only allow binding to fw_units. */
161         if (!is_fw_unit(dev))
162                 return 0;
163
164         device = fw_parent_device(unit);
165         id = container_of(drv, struct fw_driver, driver)->id_table;
166
167         for (; id->match_flags != 0; id++) {
168                 if (match_unit_directory(unit->directory, id->match_flags, id))
169                         return 1;
170
171                 /* Also check vendor ID in the root directory. */
172                 if ((id->match_flags & IEEE1394_MATCH_VENDOR_ID) &&
173                     match_unit_directory(&device->config_rom[5],
174                                 IEEE1394_MATCH_VENDOR_ID, id) &&
175                     match_unit_directory(unit->directory, id->match_flags
176                                 & ~IEEE1394_MATCH_VENDOR_ID, id))
177                         return 1;
178         }
179
180         return 0;
181 }
182
183 static void get_modalias_ids(const u32 *directory, int *id)
184 {
185         struct fw_csr_iterator ci;
186         int key, value;
187
188         fw_csr_iterator_init(&ci, directory);
189         while (fw_csr_iterator_next(&ci, &key, &value)) {
190                 switch (key) {
191                 case CSR_VENDOR:        id[0] = value; break;
192                 case CSR_MODEL:         id[1] = value; break;
193                 case CSR_SPECIFIER_ID:  id[2] = value; break;
194                 case CSR_VERSION:       id[3] = value; break;
195                 }
196         }
197 }
198
199 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
200 {
201         int id[] = {0, 0, 0, 0};
202
203         get_modalias_ids(&fw_parent_device(unit)->config_rom[5], id);
204         get_modalias_ids(unit->directory, id);
205
206         return snprintf(buffer, buffer_size,
207                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
208                         id[0], id[1], id[2], id[3]);
209 }
210
211 static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
212 {
213         struct fw_unit *unit = fw_unit(dev);
214         char modalias[64];
215
216         get_modalias(unit, modalias, sizeof(modalias));
217
218         if (add_uevent_var(env, "MODALIAS=%s", modalias))
219                 return -ENOMEM;
220
221         return 0;
222 }
223
224 struct bus_type fw_bus_type = {
225         .name = "firewire",
226         .match = fw_unit_match,
227 };
228 EXPORT_SYMBOL(fw_bus_type);
229
230 int fw_device_enable_phys_dma(struct fw_device *device)
231 {
232         int generation = device->generation;
233
234         /* device->node_id, accessed below, must not be older than generation */
235         smp_rmb();
236
237         return device->card->driver->enable_phys_dma(device->card,
238                                                      device->node_id,
239                                                      generation);
240 }
241 EXPORT_SYMBOL(fw_device_enable_phys_dma);
242
243 struct config_rom_attribute {
244         struct device_attribute attr;
245         u32 key;
246 };
247
248 static ssize_t show_immediate(struct device *dev,
249                               struct device_attribute *dattr, char *buf)
250 {
251         struct config_rom_attribute *attr =
252                 container_of(dattr, struct config_rom_attribute, attr);
253         struct fw_csr_iterator ci;
254         const u32 *dir;
255         int key, value, ret = -ENOENT;
256
257         down_read(&fw_device_rwsem);
258
259         if (is_fw_unit(dev))
260                 dir = fw_unit(dev)->directory;
261         else
262                 dir = fw_device(dev)->config_rom + 5;
263
264         fw_csr_iterator_init(&ci, dir);
265         while (fw_csr_iterator_next(&ci, &key, &value))
266                 if (attr->key == key) {
267                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
268                                        "0x%06x\n", value);
269                         break;
270                 }
271
272         up_read(&fw_device_rwsem);
273
274         return ret;
275 }
276
277 #define IMMEDIATE_ATTR(name, key)                               \
278         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
279
280 static ssize_t show_text_leaf(struct device *dev,
281                               struct device_attribute *dattr, char *buf)
282 {
283         struct config_rom_attribute *attr =
284                 container_of(dattr, struct config_rom_attribute, attr);
285         const u32 *dir;
286         size_t bufsize;
287         char dummy_buf[2];
288         int ret;
289
290         down_read(&fw_device_rwsem);
291
292         if (is_fw_unit(dev))
293                 dir = fw_unit(dev)->directory;
294         else
295                 dir = fw_device(dev)->config_rom + 5;
296
297         if (buf) {
298                 bufsize = PAGE_SIZE - 1;
299         } else {
300                 buf = dummy_buf;
301                 bufsize = 1;
302         }
303
304         ret = fw_csr_string(dir, attr->key, buf, bufsize);
305
306         if (ret >= 0) {
307                 /* Strip trailing whitespace and add newline. */
308                 while (ret > 0 && isspace(buf[ret - 1]))
309                         ret--;
310                 strcpy(buf + ret, "\n");
311                 ret++;
312         }
313
314         up_read(&fw_device_rwsem);
315
316         return ret;
317 }
318
319 #define TEXT_LEAF_ATTR(name, key)                               \
320         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
321
322 static struct config_rom_attribute config_rom_attributes[] = {
323         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
324         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
325         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
326         IMMEDIATE_ATTR(version, CSR_VERSION),
327         IMMEDIATE_ATTR(model, CSR_MODEL),
328         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
329         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
330         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
331 };
332
333 static void init_fw_attribute_group(struct device *dev,
334                                     struct device_attribute *attrs,
335                                     struct fw_attribute_group *group)
336 {
337         struct device_attribute *attr;
338         int i, j;
339
340         for (j = 0; attrs[j].attr.name != NULL; j++)
341                 group->attrs[j] = &attrs[j].attr;
342
343         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
344                 attr = &config_rom_attributes[i].attr;
345                 if (attr->show(dev, attr, NULL) < 0)
346                         continue;
347                 group->attrs[j++] = &attr->attr;
348         }
349
350         group->attrs[j] = NULL;
351         group->groups[0] = &group->group;
352         group->groups[1] = NULL;
353         group->group.attrs = group->attrs;
354         dev->groups = (const struct attribute_group **) group->groups;
355 }
356
357 static ssize_t modalias_show(struct device *dev,
358                              struct device_attribute *attr, char *buf)
359 {
360         struct fw_unit *unit = fw_unit(dev);
361         int length;
362
363         length = get_modalias(unit, buf, PAGE_SIZE);
364         strcpy(buf + length, "\n");
365
366         return length + 1;
367 }
368
369 static ssize_t rom_index_show(struct device *dev,
370                               struct device_attribute *attr, char *buf)
371 {
372         struct fw_device *device = fw_device(dev->parent);
373         struct fw_unit *unit = fw_unit(dev);
374
375         return snprintf(buf, PAGE_SIZE, "%d\n",
376                         (int)(unit->directory - device->config_rom));
377 }
378
379 static struct device_attribute fw_unit_attributes[] = {
380         __ATTR_RO(modalias),
381         __ATTR_RO(rom_index),
382         __ATTR_NULL,
383 };
384
385 static ssize_t config_rom_show(struct device *dev,
386                                struct device_attribute *attr, char *buf)
387 {
388         struct fw_device *device = fw_device(dev);
389         size_t length;
390
391         down_read(&fw_device_rwsem);
392         length = device->config_rom_length * 4;
393         memcpy(buf, device->config_rom, length);
394         up_read(&fw_device_rwsem);
395
396         return length;
397 }
398
399 static ssize_t guid_show(struct device *dev,
400                          struct device_attribute *attr, char *buf)
401 {
402         struct fw_device *device = fw_device(dev);
403         int ret;
404
405         down_read(&fw_device_rwsem);
406         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
407                        device->config_rom[3], device->config_rom[4]);
408         up_read(&fw_device_rwsem);
409
410         return ret;
411 }
412
413 static int units_sprintf(char *buf, const u32 *directory)
414 {
415         struct fw_csr_iterator ci;
416         int key, value;
417         int specifier_id = 0;
418         int version = 0;
419
420         fw_csr_iterator_init(&ci, directory);
421         while (fw_csr_iterator_next(&ci, &key, &value)) {
422                 switch (key) {
423                 case CSR_SPECIFIER_ID:
424                         specifier_id = value;
425                         break;
426                 case CSR_VERSION:
427                         version = value;
428                         break;
429                 }
430         }
431
432         return sprintf(buf, "0x%06x:0x%06x ", specifier_id, version);
433 }
434
435 static ssize_t units_show(struct device *dev,
436                           struct device_attribute *attr, char *buf)
437 {
438         struct fw_device *device = fw_device(dev);
439         struct fw_csr_iterator ci;
440         int key, value, i = 0;
441
442         down_read(&fw_device_rwsem);
443         fw_csr_iterator_init(&ci, &device->config_rom[5]);
444         while (fw_csr_iterator_next(&ci, &key, &value)) {
445                 if (key != (CSR_UNIT | CSR_DIRECTORY))
446                         continue;
447                 i += units_sprintf(&buf[i], ci.p + value - 1);
448                 if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
449                         break;
450         }
451         up_read(&fw_device_rwsem);
452
453         if (i)
454                 buf[i - 1] = '\n';
455
456         return i;
457 }
458
459 static struct device_attribute fw_device_attributes[] = {
460         __ATTR_RO(config_rom),
461         __ATTR_RO(guid),
462         __ATTR_RO(units),
463         __ATTR_NULL,
464 };
465
466 static int read_rom(struct fw_device *device,
467                     int generation, int index, u32 *data)
468 {
469         int rcode;
470
471         /* device->node_id, accessed below, must not be older than generation */
472         smp_rmb();
473
474         rcode = fw_run_transaction(device->card, TCODE_READ_QUADLET_REQUEST,
475                         device->node_id, generation, device->max_speed,
476                         (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4,
477                         data, 4);
478         be32_to_cpus(data);
479
480         return rcode;
481 }
482
483 #define MAX_CONFIG_ROM_SIZE 256
484
485 /*
486  * Read the bus info block, perform a speed probe, and read all of the rest of
487  * the config ROM.  We do all this with a cached bus generation.  If the bus
488  * generation changes under us, read_config_rom will fail and get retried.
489  * It's better to start all over in this case because the node from which we
490  * are reading the ROM may have changed the ROM during the reset.
491  */
492 static int read_config_rom(struct fw_device *device, int generation)
493 {
494         const u32 *old_rom, *new_rom;
495         u32 *rom, *stack;
496         u32 sp, key;
497         int i, end, length, ret = -1;
498
499         rom = kmalloc(sizeof(*rom) * MAX_CONFIG_ROM_SIZE +
500                       sizeof(*stack) * MAX_CONFIG_ROM_SIZE, GFP_KERNEL);
501         if (rom == NULL)
502                 return -ENOMEM;
503
504         stack = &rom[MAX_CONFIG_ROM_SIZE];
505         memset(rom, 0, sizeof(*rom) * MAX_CONFIG_ROM_SIZE);
506
507         device->max_speed = SCODE_100;
508
509         /* First read the bus info block. */
510         for (i = 0; i < 5; i++) {
511                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
512                         goto out;
513                 /*
514                  * As per IEEE1212 7.2, during power-up, devices can
515                  * reply with a 0 for the first quadlet of the config
516                  * rom to indicate that they are booting (for example,
517                  * if the firmware is on the disk of a external
518                  * harddisk).  In that case we just fail, and the
519                  * retry mechanism will try again later.
520                  */
521                 if (i == 0 && rom[i] == 0)
522                         goto out;
523         }
524
525         device->max_speed = device->node->max_speed;
526
527         /*
528          * Determine the speed of
529          *   - devices with link speed less than PHY speed,
530          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
531          *   - all devices if there are 1394b repeaters.
532          * Note, we cannot use the bus info block's link_spd as starting point
533          * because some buggy firmwares set it lower than necessary and because
534          * 1394-1995 nodes do not have the field.
535          */
536         if ((rom[2] & 0x7) < device->max_speed ||
537             device->max_speed == SCODE_BETA ||
538             device->card->beta_repeaters_present) {
539                 u32 dummy;
540
541                 /* for S1600 and S3200 */
542                 if (device->max_speed == SCODE_BETA)
543                         device->max_speed = device->card->link_speed;
544
545                 while (device->max_speed > SCODE_100) {
546                         if (read_rom(device, generation, 0, &dummy) ==
547                             RCODE_COMPLETE)
548                                 break;
549                         device->max_speed--;
550                 }
551         }
552
553         /*
554          * Now parse the config rom.  The config rom is a recursive
555          * directory structure so we parse it using a stack of
556          * references to the blocks that make up the structure.  We
557          * push a reference to the root directory on the stack to
558          * start things off.
559          */
560         length = i;
561         sp = 0;
562         stack[sp++] = 0xc0000005;
563         while (sp > 0) {
564                 /*
565                  * Pop the next block reference of the stack.  The
566                  * lower 24 bits is the offset into the config rom,
567                  * the upper 8 bits are the type of the reference the
568                  * block.
569                  */
570                 key = stack[--sp];
571                 i = key & 0xffffff;
572                 if (WARN_ON(i >= MAX_CONFIG_ROM_SIZE))
573                         goto out;
574
575                 /* Read header quadlet for the block to get the length. */
576                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
577                         goto out;
578                 end = i + (rom[i] >> 16) + 1;
579                 if (end > MAX_CONFIG_ROM_SIZE) {
580                         /*
581                          * This block extends outside the config ROM which is
582                          * a firmware bug.  Ignore this whole block, i.e.
583                          * simply set a fake block length of 0.
584                          */
585                         fw_error("skipped invalid ROM block %x at %llx\n",
586                                  rom[i],
587                                  i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
588                         rom[i] = 0;
589                         end = i;
590                 }
591                 i++;
592
593                 /*
594                  * Now read in the block.  If this is a directory
595                  * block, check the entries as we read them to see if
596                  * it references another block, and push it in that case.
597                  */
598                 for (; i < end; i++) {
599                         if (read_rom(device, generation, i, &rom[i]) !=
600                             RCODE_COMPLETE)
601                                 goto out;
602
603                         if ((key >> 30) != 3 || (rom[i] >> 30) < 2)
604                                 continue;
605                         /*
606                          * Offset points outside the ROM.  May be a firmware
607                          * bug or an Extended ROM entry (IEEE 1212-2001 clause
608                          * 7.7.18).  Simply overwrite this pointer here by a
609                          * fake immediate entry so that later iterators over
610                          * the ROM don't have to check offsets all the time.
611                          */
612                         if (i + (rom[i] & 0xffffff) >= MAX_CONFIG_ROM_SIZE) {
613                                 fw_error("skipped unsupported ROM entry %x at %llx\n",
614                                          rom[i],
615                                          i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
616                                 rom[i] = 0;
617                                 continue;
618                         }
619                         stack[sp++] = i + rom[i];
620                 }
621                 if (length < i)
622                         length = i;
623         }
624
625         old_rom = device->config_rom;
626         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
627         if (new_rom == NULL)
628                 goto out;
629
630         down_write(&fw_device_rwsem);
631         device->config_rom = new_rom;
632         device->config_rom_length = length;
633         up_write(&fw_device_rwsem);
634
635         kfree(old_rom);
636         ret = 0;
637         device->max_rec = rom[2] >> 12 & 0xf;
638         device->cmc     = rom[2] >> 30 & 1;
639         device->irmc    = rom[2] >> 31 & 1;
640  out:
641         kfree(rom);
642
643         return ret;
644 }
645
646 static void fw_unit_release(struct device *dev)
647 {
648         struct fw_unit *unit = fw_unit(dev);
649
650         kfree(unit);
651 }
652
653 static struct device_type fw_unit_type = {
654         .uevent         = fw_unit_uevent,
655         .release        = fw_unit_release,
656 };
657
658 static bool is_fw_unit(struct device *dev)
659 {
660         return dev->type == &fw_unit_type;
661 }
662
663 static void create_units(struct fw_device *device)
664 {
665         struct fw_csr_iterator ci;
666         struct fw_unit *unit;
667         int key, value, i;
668
669         i = 0;
670         fw_csr_iterator_init(&ci, &device->config_rom[5]);
671         while (fw_csr_iterator_next(&ci, &key, &value)) {
672                 if (key != (CSR_UNIT | CSR_DIRECTORY))
673                         continue;
674
675                 /*
676                  * Get the address of the unit directory and try to
677                  * match the drivers id_tables against it.
678                  */
679                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
680                 if (unit == NULL) {
681                         fw_error("failed to allocate memory for unit\n");
682                         continue;
683                 }
684
685                 unit->directory = ci.p + value - 1;
686                 unit->device.bus = &fw_bus_type;
687                 unit->device.type = &fw_unit_type;
688                 unit->device.parent = &device->device;
689                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
690
691                 BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
692                                 ARRAY_SIZE(fw_unit_attributes) +
693                                 ARRAY_SIZE(config_rom_attributes));
694                 init_fw_attribute_group(&unit->device,
695                                         fw_unit_attributes,
696                                         &unit->attribute_group);
697
698                 if (device_register(&unit->device) < 0)
699                         goto skip_unit;
700
701                 continue;
702
703         skip_unit:
704                 kfree(unit);
705         }
706 }
707
708 static int shutdown_unit(struct device *device, void *data)
709 {
710         device_unregister(device);
711
712         return 0;
713 }
714
715 /*
716  * fw_device_rwsem acts as dual purpose mutex:
717  *   - serializes accesses to fw_device_idr,
718  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
719  *     fw_unit.directory, unless those accesses happen at safe occasions
720  */
721 DECLARE_RWSEM(fw_device_rwsem);
722
723 DEFINE_IDR(fw_device_idr);
724 int fw_cdev_major;
725
726 struct fw_device *fw_device_get_by_devt(dev_t devt)
727 {
728         struct fw_device *device;
729
730         down_read(&fw_device_rwsem);
731         device = idr_find(&fw_device_idr, MINOR(devt));
732         if (device)
733                 fw_device_get(device);
734         up_read(&fw_device_rwsem);
735
736         return device;
737 }
738
739 /*
740  * These defines control the retry behavior for reading the config
741  * rom.  It shouldn't be necessary to tweak these; if the device
742  * doesn't respond to a config rom read within 10 seconds, it's not
743  * going to respond at all.  As for the initial delay, a lot of
744  * devices will be able to respond within half a second after bus
745  * reset.  On the other hand, it's not really worth being more
746  * aggressive than that, since it scales pretty well; if 10 devices
747  * are plugged in, they're all getting read within one second.
748  */
749
750 #define MAX_RETRIES     10
751 #define RETRY_DELAY     (3 * HZ)
752 #define INITIAL_DELAY   (HZ / 2)
753 #define SHUTDOWN_DELAY  (2 * HZ)
754
755 static void fw_device_shutdown(struct work_struct *work)
756 {
757         struct fw_device *device =
758                 container_of(work, struct fw_device, work.work);
759         int minor = MINOR(device->device.devt);
760
761         if (time_is_after_jiffies(device->card->reset_jiffies + SHUTDOWN_DELAY)
762             && !list_empty(&device->card->link)) {
763                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
764                 return;
765         }
766
767         if (atomic_cmpxchg(&device->state,
768                            FW_DEVICE_GONE,
769                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
770                 return;
771
772         fw_device_cdev_remove(device);
773         device_for_each_child(&device->device, NULL, shutdown_unit);
774         device_unregister(&device->device);
775
776         down_write(&fw_device_rwsem);
777         idr_remove(&fw_device_idr, minor);
778         up_write(&fw_device_rwsem);
779
780         fw_device_put(device);
781 }
782
783 static void fw_device_release(struct device *dev)
784 {
785         struct fw_device *device = fw_device(dev);
786         struct fw_card *card = device->card;
787         unsigned long flags;
788
789         /*
790          * Take the card lock so we don't set this to NULL while a
791          * FW_NODE_UPDATED callback is being handled or while the
792          * bus manager work looks at this node.
793          */
794         spin_lock_irqsave(&card->lock, flags);
795         device->node->data = NULL;
796         spin_unlock_irqrestore(&card->lock, flags);
797
798         fw_node_put(device->node);
799         kfree(device->config_rom);
800         kfree(device);
801         fw_card_put(card);
802 }
803
804 static struct device_type fw_device_type = {
805         .release = fw_device_release,
806 };
807
808 static bool is_fw_device(struct device *dev)
809 {
810         return dev->type == &fw_device_type;
811 }
812
813 static int update_unit(struct device *dev, void *data)
814 {
815         struct fw_unit *unit = fw_unit(dev);
816         struct fw_driver *driver = (struct fw_driver *)dev->driver;
817
818         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
819                 down(&dev->sem);
820                 driver->update(unit);
821                 up(&dev->sem);
822         }
823
824         return 0;
825 }
826
827 static void fw_device_update(struct work_struct *work)
828 {
829         struct fw_device *device =
830                 container_of(work, struct fw_device, work.work);
831
832         fw_device_cdev_update(device);
833         device_for_each_child(&device->device, NULL, update_unit);
834 }
835
836 /*
837  * If a device was pending for deletion because its node went away but its
838  * bus info block and root directory header matches that of a newly discovered
839  * device, revive the existing fw_device.
840  * The newly allocated fw_device becomes obsolete instead.
841  */
842 static int lookup_existing_device(struct device *dev, void *data)
843 {
844         struct fw_device *old = fw_device(dev);
845         struct fw_device *new = data;
846         struct fw_card *card = new->card;
847         int match = 0;
848
849         if (!is_fw_device(dev))
850                 return 0;
851
852         down_read(&fw_device_rwsem); /* serialize config_rom access */
853         spin_lock_irq(&card->lock);  /* serialize node access */
854
855         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
856             atomic_cmpxchg(&old->state,
857                            FW_DEVICE_GONE,
858                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
859                 struct fw_node *current_node = new->node;
860                 struct fw_node *obsolete_node = old->node;
861
862                 new->node = obsolete_node;
863                 new->node->data = new;
864                 old->node = current_node;
865                 old->node->data = old;
866
867                 old->max_speed = new->max_speed;
868                 old->node_id = current_node->node_id;
869                 smp_wmb();  /* update node_id before generation */
870                 old->generation = card->generation;
871                 old->config_rom_retries = 0;
872                 fw_notify("rediscovered device %s\n", dev_name(dev));
873
874                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
875                 schedule_delayed_work(&old->work, 0);
876
877                 if (current_node == card->root_node)
878                         fw_schedule_bm_work(card, 0);
879
880                 match = 1;
881         }
882
883         spin_unlock_irq(&card->lock);
884         up_read(&fw_device_rwsem);
885
886         return match;
887 }
888
889 enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
890
891 static void set_broadcast_channel(struct fw_device *device, int generation)
892 {
893         struct fw_card *card = device->card;
894         __be32 data;
895         int rcode;
896
897         if (!card->broadcast_channel_allocated)
898                 return;
899
900         /*
901          * The Broadcast_Channel Valid bit is required by nodes which want to
902          * transmit on this channel.  Such transmissions are practically
903          * exclusive to IP over 1394 (RFC 2734).  IP capable nodes are required
904          * to be IRM capable and have a max_rec of 8 or more.  We use this fact
905          * to narrow down to which nodes we send Broadcast_Channel updates.
906          */
907         if (!device->irmc || device->max_rec < 8)
908                 return;
909
910         /*
911          * Some 1394-1995 nodes crash if this 1394a-2000 register is written.
912          * Perform a read test first.
913          */
914         if (device->bc_implemented == BC_UNKNOWN) {
915                 rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
916                                 device->node_id, generation, device->max_speed,
917                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
918                                 &data, 4);
919                 switch (rcode) {
920                 case RCODE_COMPLETE:
921                         if (data & cpu_to_be32(1 << 31)) {
922                                 device->bc_implemented = BC_IMPLEMENTED;
923                                 break;
924                         }
925                         /* else fall through to case address error */
926                 case RCODE_ADDRESS_ERROR:
927                         device->bc_implemented = BC_UNIMPLEMENTED;
928                 }
929         }
930
931         if (device->bc_implemented == BC_IMPLEMENTED) {
932                 data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
933                                    BROADCAST_CHANNEL_VALID);
934                 fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
935                                 device->node_id, generation, device->max_speed,
936                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
937                                 &data, 4);
938         }
939 }
940
941 int fw_device_set_broadcast_channel(struct device *dev, void *gen)
942 {
943         if (is_fw_device(dev))
944                 set_broadcast_channel(fw_device(dev), (long)gen);
945
946         return 0;
947 }
948
949 static void fw_device_init(struct work_struct *work)
950 {
951         struct fw_device *device =
952                 container_of(work, struct fw_device, work.work);
953         struct device *revived_dev;
954         int minor, ret;
955
956         /*
957          * All failure paths here set node->data to NULL, so that we
958          * don't try to do device_for_each_child() on a kfree()'d
959          * device.
960          */
961
962         if (read_config_rom(device, device->generation) < 0) {
963                 if (device->config_rom_retries < MAX_RETRIES &&
964                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
965                         device->config_rom_retries++;
966                         schedule_delayed_work(&device->work, RETRY_DELAY);
967                 } else {
968                         fw_notify("giving up on config rom for node id %x\n",
969                                   device->node_id);
970                         if (device->node == device->card->root_node)
971                                 fw_schedule_bm_work(device->card, 0);
972                         fw_device_release(&device->device);
973                 }
974                 return;
975         }
976
977         revived_dev = device_find_child(device->card->device,
978                                         device, lookup_existing_device);
979         if (revived_dev) {
980                 put_device(revived_dev);
981                 fw_device_release(&device->device);
982
983                 return;
984         }
985
986         device_initialize(&device->device);
987
988         fw_device_get(device);
989         down_write(&fw_device_rwsem);
990         ret = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
991               idr_get_new(&fw_device_idr, device, &minor) :
992               -ENOMEM;
993         up_write(&fw_device_rwsem);
994
995         if (ret < 0)
996                 goto error;
997
998         device->device.bus = &fw_bus_type;
999         device->device.type = &fw_device_type;
1000         device->device.parent = device->card->device;
1001         device->device.devt = MKDEV(fw_cdev_major, minor);
1002         dev_set_name(&device->device, "fw%d", minor);
1003
1004         BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
1005                         ARRAY_SIZE(fw_device_attributes) +
1006                         ARRAY_SIZE(config_rom_attributes));
1007         init_fw_attribute_group(&device->device,
1008                                 fw_device_attributes,
1009                                 &device->attribute_group);
1010
1011         if (device_add(&device->device)) {
1012                 fw_error("Failed to add device.\n");
1013                 goto error_with_cdev;
1014         }
1015
1016         create_units(device);
1017
1018         /*
1019          * Transition the device to running state.  If it got pulled
1020          * out from under us while we did the intialization work, we
1021          * have to shut down the device again here.  Normally, though,
1022          * fw_node_event will be responsible for shutting it down when
1023          * necessary.  We have to use the atomic cmpxchg here to avoid
1024          * racing with the FW_NODE_DESTROYED case in
1025          * fw_node_event().
1026          */
1027         if (atomic_cmpxchg(&device->state,
1028                            FW_DEVICE_INITIALIZING,
1029                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
1030                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1031                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
1032         } else {
1033                 if (device->config_rom_retries)
1034                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
1035                                   "%d config ROM retries\n",
1036                                   dev_name(&device->device),
1037                                   device->config_rom[3], device->config_rom[4],
1038                                   1 << device->max_speed,
1039                                   device->config_rom_retries);
1040                 else
1041                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
1042                                   dev_name(&device->device),
1043                                   device->config_rom[3], device->config_rom[4],
1044                                   1 << device->max_speed);
1045                 device->config_rom_retries = 0;
1046
1047                 set_broadcast_channel(device, device->generation);
1048         }
1049
1050         /*
1051          * Reschedule the IRM work if we just finished reading the
1052          * root node config rom.  If this races with a bus reset we
1053          * just end up running the IRM work a couple of extra times -
1054          * pretty harmless.
1055          */
1056         if (device->node == device->card->root_node)
1057                 fw_schedule_bm_work(device->card, 0);
1058
1059         return;
1060
1061  error_with_cdev:
1062         down_write(&fw_device_rwsem);
1063         idr_remove(&fw_device_idr, minor);
1064         up_write(&fw_device_rwsem);
1065  error:
1066         fw_device_put(device);          /* fw_device_idr's reference */
1067
1068         put_device(&device->device);    /* our reference */
1069 }
1070
1071 enum {
1072         REREAD_BIB_ERROR,
1073         REREAD_BIB_GONE,
1074         REREAD_BIB_UNCHANGED,
1075         REREAD_BIB_CHANGED,
1076 };
1077
1078 /* Reread and compare bus info block and header of root directory */
1079 static int reread_config_rom(struct fw_device *device, int generation)
1080 {
1081         u32 q;
1082         int i;
1083
1084         for (i = 0; i < 6; i++) {
1085                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
1086                         return REREAD_BIB_ERROR;
1087
1088                 if (i == 0 && q == 0)
1089                         return REREAD_BIB_GONE;
1090
1091                 if (q != device->config_rom[i])
1092                         return REREAD_BIB_CHANGED;
1093         }
1094
1095         return REREAD_BIB_UNCHANGED;
1096 }
1097
1098 static void fw_device_refresh(struct work_struct *work)
1099 {
1100         struct fw_device *device =
1101                 container_of(work, struct fw_device, work.work);
1102         struct fw_card *card = device->card;
1103         int node_id = device->node_id;
1104
1105         switch (reread_config_rom(device, device->generation)) {
1106         case REREAD_BIB_ERROR:
1107                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
1108                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1109                         device->config_rom_retries++;
1110                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
1111
1112                         return;
1113                 }
1114                 goto give_up;
1115
1116         case REREAD_BIB_GONE:
1117                 goto gone;
1118
1119         case REREAD_BIB_UNCHANGED:
1120                 if (atomic_cmpxchg(&device->state,
1121                                    FW_DEVICE_INITIALIZING,
1122                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1123                         goto gone;
1124
1125                 fw_device_update(work);
1126                 device->config_rom_retries = 0;
1127                 goto out;
1128
1129         case REREAD_BIB_CHANGED:
1130                 break;
1131         }
1132
1133         /*
1134          * Something changed.  We keep things simple and don't investigate
1135          * further.  We just destroy all previous units and create new ones.
1136          */
1137         device_for_each_child(&device->device, NULL, shutdown_unit);
1138
1139         if (read_config_rom(device, device->generation) < 0) {
1140                 if (device->config_rom_retries < MAX_RETRIES &&
1141                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1142                         device->config_rom_retries++;
1143                         schedule_delayed_work(&device->work, RETRY_DELAY);
1144
1145                         return;
1146                 }
1147                 goto give_up;
1148         }
1149
1150         create_units(device);
1151
1152         /* Userspace may want to re-read attributes. */
1153         kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1154
1155         if (atomic_cmpxchg(&device->state,
1156                            FW_DEVICE_INITIALIZING,
1157                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1158                 goto gone;
1159
1160         fw_notify("refreshed device %s\n", dev_name(&device->device));
1161         device->config_rom_retries = 0;
1162         goto out;
1163
1164  give_up:
1165         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
1166  gone:
1167         atomic_set(&device->state, FW_DEVICE_GONE);
1168         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1169         schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
1170  out:
1171         if (node_id == card->root_node->node_id)
1172                 fw_schedule_bm_work(card, 0);
1173 }
1174
1175 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1176 {
1177         struct fw_device *device;
1178
1179         switch (event) {
1180         case FW_NODE_CREATED:
1181         case FW_NODE_LINK_ON:
1182                 if (!node->link_on)
1183                         break;
1184  create:
1185                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
1186                 if (device == NULL)
1187                         break;
1188
1189                 /*
1190                  * Do minimal intialization of the device here, the
1191                  * rest will happen in fw_device_init().
1192                  *
1193                  * Attention:  A lot of things, even fw_device_get(),
1194                  * cannot be done before fw_device_init() finished!
1195                  * You can basically just check device->state and
1196                  * schedule work until then, but only while holding
1197                  * card->lock.
1198                  */
1199                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1200                 device->card = fw_card_get(card);
1201                 device->node = fw_node_get(node);
1202                 device->node_id = node->node_id;
1203                 device->generation = card->generation;
1204                 device->is_local = node == card->local_node;
1205                 mutex_init(&device->client_list_mutex);
1206                 INIT_LIST_HEAD(&device->client_list);
1207
1208                 /*
1209                  * Set the node data to point back to this device so
1210                  * FW_NODE_UPDATED callbacks can update the node_id
1211                  * and generation for the device.
1212                  */
1213                 node->data = device;
1214
1215                 /*
1216                  * Many devices are slow to respond after bus resets,
1217                  * especially if they are bus powered and go through
1218                  * power-up after getting plugged in.  We schedule the
1219                  * first config rom scan half a second after bus reset.
1220                  */
1221                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1222                 schedule_delayed_work(&device->work, INITIAL_DELAY);
1223                 break;
1224
1225         case FW_NODE_INITIATED_RESET:
1226                 device = node->data;
1227                 if (device == NULL)
1228                         goto create;
1229
1230                 device->node_id = node->node_id;
1231                 smp_wmb();  /* update node_id before generation */
1232                 device->generation = card->generation;
1233                 if (atomic_cmpxchg(&device->state,
1234                             FW_DEVICE_RUNNING,
1235                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1236                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1237                         schedule_delayed_work(&device->work,
1238                                 device->is_local ? 0 : INITIAL_DELAY);
1239                 }
1240                 break;
1241
1242         case FW_NODE_UPDATED:
1243                 if (!node->link_on || node->data == NULL)
1244                         break;
1245
1246                 device = node->data;
1247                 device->node_id = node->node_id;
1248                 smp_wmb();  /* update node_id before generation */
1249                 device->generation = card->generation;
1250                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1251                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1252                         schedule_delayed_work(&device->work, 0);
1253                 }
1254                 break;
1255
1256         case FW_NODE_DESTROYED:
1257         case FW_NODE_LINK_OFF:
1258                 if (!node->data)
1259                         break;
1260
1261                 /*
1262                  * Destroy the device associated with the node.  There
1263                  * are two cases here: either the device is fully
1264                  * initialized (FW_DEVICE_RUNNING) or we're in the
1265                  * process of reading its config rom
1266                  * (FW_DEVICE_INITIALIZING).  If it is fully
1267                  * initialized we can reuse device->work to schedule a
1268                  * full fw_device_shutdown().  If not, there's work
1269                  * scheduled to read it's config rom, and we just put
1270                  * the device in shutdown state to have that code fail
1271                  * to create the device.
1272                  */
1273                 device = node->data;
1274                 if (atomic_xchg(&device->state,
1275                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1276                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1277                         schedule_delayed_work(&device->work,
1278                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1279                 }
1280                 break;
1281         }
1282 }