014cabd3afda56122bb433646a71f0180b3252e5
[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 int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
184 {
185         struct fw_device *device = fw_parent_device(unit);
186         struct fw_csr_iterator ci;
187
188         int key, value;
189         int vendor = 0;
190         int model = 0;
191         int specifier_id = 0;
192         int version = 0;
193
194         fw_csr_iterator_init(&ci, &device->config_rom[5]);
195         while (fw_csr_iterator_next(&ci, &key, &value)) {
196                 switch (key) {
197                 case CSR_VENDOR:
198                         vendor = value;
199                         break;
200                 case CSR_MODEL:
201                         model = value;
202                         break;
203                 }
204         }
205
206         fw_csr_iterator_init(&ci, unit->directory);
207         while (fw_csr_iterator_next(&ci, &key, &value)) {
208                 switch (key) {
209                 case CSR_SPECIFIER_ID:
210                         specifier_id = value;
211                         break;
212                 case CSR_VERSION:
213                         version = value;
214                         break;
215                 }
216         }
217
218         return snprintf(buffer, buffer_size,
219                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
220                         vendor, model, specifier_id, version);
221 }
222
223 static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
224 {
225         struct fw_unit *unit = fw_unit(dev);
226         char modalias[64];
227
228         get_modalias(unit, modalias, sizeof(modalias));
229
230         if (add_uevent_var(env, "MODALIAS=%s", modalias))
231                 return -ENOMEM;
232
233         return 0;
234 }
235
236 struct bus_type fw_bus_type = {
237         .name = "firewire",
238         .match = fw_unit_match,
239 };
240 EXPORT_SYMBOL(fw_bus_type);
241
242 int fw_device_enable_phys_dma(struct fw_device *device)
243 {
244         int generation = device->generation;
245
246         /* device->node_id, accessed below, must not be older than generation */
247         smp_rmb();
248
249         return device->card->driver->enable_phys_dma(device->card,
250                                                      device->node_id,
251                                                      generation);
252 }
253 EXPORT_SYMBOL(fw_device_enable_phys_dma);
254
255 struct config_rom_attribute {
256         struct device_attribute attr;
257         u32 key;
258 };
259
260 static ssize_t show_immediate(struct device *dev,
261                               struct device_attribute *dattr, char *buf)
262 {
263         struct config_rom_attribute *attr =
264                 container_of(dattr, struct config_rom_attribute, attr);
265         struct fw_csr_iterator ci;
266         const u32 *dir;
267         int key, value, ret = -ENOENT;
268
269         down_read(&fw_device_rwsem);
270
271         if (is_fw_unit(dev))
272                 dir = fw_unit(dev)->directory;
273         else
274                 dir = fw_device(dev)->config_rom + 5;
275
276         fw_csr_iterator_init(&ci, dir);
277         while (fw_csr_iterator_next(&ci, &key, &value))
278                 if (attr->key == key) {
279                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
280                                        "0x%06x\n", value);
281                         break;
282                 }
283
284         up_read(&fw_device_rwsem);
285
286         return ret;
287 }
288
289 #define IMMEDIATE_ATTR(name, key)                               \
290         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
291
292 static ssize_t show_text_leaf(struct device *dev,
293                               struct device_attribute *dattr, char *buf)
294 {
295         struct config_rom_attribute *attr =
296                 container_of(dattr, struct config_rom_attribute, attr);
297         const u32 *dir;
298         size_t bufsize;
299         char dummy_buf[2];
300         int ret;
301
302         down_read(&fw_device_rwsem);
303
304         if (is_fw_unit(dev))
305                 dir = fw_unit(dev)->directory;
306         else
307                 dir = fw_device(dev)->config_rom + 5;
308
309         if (buf) {
310                 bufsize = PAGE_SIZE - 1;
311         } else {
312                 buf = dummy_buf;
313                 bufsize = 1;
314         }
315
316         ret = fw_csr_string(dir, attr->key, buf, bufsize);
317
318         if (ret >= 0) {
319                 /* Strip trailing whitespace and add newline. */
320                 while (ret > 0 && isspace(buf[ret - 1]))
321                         ret--;
322                 strcpy(buf + ret, "\n");
323                 ret++;
324         }
325
326         up_read(&fw_device_rwsem);
327
328         return ret;
329 }
330
331 #define TEXT_LEAF_ATTR(name, key)                               \
332         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
333
334 static struct config_rom_attribute config_rom_attributes[] = {
335         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
336         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
337         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
338         IMMEDIATE_ATTR(version, CSR_VERSION),
339         IMMEDIATE_ATTR(model, CSR_MODEL),
340         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
341         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
342         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
343 };
344
345 static void init_fw_attribute_group(struct device *dev,
346                                     struct device_attribute *attrs,
347                                     struct fw_attribute_group *group)
348 {
349         struct device_attribute *attr;
350         int i, j;
351
352         for (j = 0; attrs[j].attr.name != NULL; j++)
353                 group->attrs[j] = &attrs[j].attr;
354
355         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
356                 attr = &config_rom_attributes[i].attr;
357                 if (attr->show(dev, attr, NULL) < 0)
358                         continue;
359                 group->attrs[j++] = &attr->attr;
360         }
361
362         group->attrs[j] = NULL;
363         group->groups[0] = &group->group;
364         group->groups[1] = NULL;
365         group->group.attrs = group->attrs;
366         dev->groups = (const struct attribute_group **) group->groups;
367 }
368
369 static ssize_t modalias_show(struct device *dev,
370                              struct device_attribute *attr, char *buf)
371 {
372         struct fw_unit *unit = fw_unit(dev);
373         int length;
374
375         length = get_modalias(unit, buf, PAGE_SIZE);
376         strcpy(buf + length, "\n");
377
378         return length + 1;
379 }
380
381 static ssize_t rom_index_show(struct device *dev,
382                               struct device_attribute *attr, char *buf)
383 {
384         struct fw_device *device = fw_device(dev->parent);
385         struct fw_unit *unit = fw_unit(dev);
386
387         return snprintf(buf, PAGE_SIZE, "%d\n",
388                         (int)(unit->directory - device->config_rom));
389 }
390
391 static struct device_attribute fw_unit_attributes[] = {
392         __ATTR_RO(modalias),
393         __ATTR_RO(rom_index),
394         __ATTR_NULL,
395 };
396
397 static ssize_t config_rom_show(struct device *dev,
398                                struct device_attribute *attr, char *buf)
399 {
400         struct fw_device *device = fw_device(dev);
401         size_t length;
402
403         down_read(&fw_device_rwsem);
404         length = device->config_rom_length * 4;
405         memcpy(buf, device->config_rom, length);
406         up_read(&fw_device_rwsem);
407
408         return length;
409 }
410
411 static ssize_t guid_show(struct device *dev,
412                          struct device_attribute *attr, char *buf)
413 {
414         struct fw_device *device = fw_device(dev);
415         int ret;
416
417         down_read(&fw_device_rwsem);
418         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
419                        device->config_rom[3], device->config_rom[4]);
420         up_read(&fw_device_rwsem);
421
422         return ret;
423 }
424
425 static int units_sprintf(char *buf, const u32 *directory)
426 {
427         struct fw_csr_iterator ci;
428         int key, value;
429         int specifier_id = 0;
430         int version = 0;
431
432         fw_csr_iterator_init(&ci, directory);
433         while (fw_csr_iterator_next(&ci, &key, &value)) {
434                 switch (key) {
435                 case CSR_SPECIFIER_ID:
436                         specifier_id = value;
437                         break;
438                 case CSR_VERSION:
439                         version = value;
440                         break;
441                 }
442         }
443
444         return sprintf(buf, "0x%06x:0x%06x ", specifier_id, version);
445 }
446
447 static ssize_t units_show(struct device *dev,
448                           struct device_attribute *attr, char *buf)
449 {
450         struct fw_device *device = fw_device(dev);
451         struct fw_csr_iterator ci;
452         int key, value, i = 0;
453
454         down_read(&fw_device_rwsem);
455         fw_csr_iterator_init(&ci, &device->config_rom[5]);
456         while (fw_csr_iterator_next(&ci, &key, &value)) {
457                 if (key != (CSR_UNIT | CSR_DIRECTORY))
458                         continue;
459                 i += units_sprintf(&buf[i], ci.p + value - 1);
460                 if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
461                         break;
462         }
463         up_read(&fw_device_rwsem);
464
465         if (i)
466                 buf[i - 1] = '\n';
467
468         return i;
469 }
470
471 static struct device_attribute fw_device_attributes[] = {
472         __ATTR_RO(config_rom),
473         __ATTR_RO(guid),
474         __ATTR_RO(units),
475         __ATTR_NULL,
476 };
477
478 static int read_rom(struct fw_device *device,
479                     int generation, int index, u32 *data)
480 {
481         int rcode;
482
483         /* device->node_id, accessed below, must not be older than generation */
484         smp_rmb();
485
486         rcode = fw_run_transaction(device->card, TCODE_READ_QUADLET_REQUEST,
487                         device->node_id, generation, device->max_speed,
488                         (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4,
489                         data, 4);
490         be32_to_cpus(data);
491
492         return rcode;
493 }
494
495 #define MAX_CONFIG_ROM_SIZE 256
496
497 /*
498  * Read the bus info block, perform a speed probe, and read all of the rest of
499  * the config ROM.  We do all this with a cached bus generation.  If the bus
500  * generation changes under us, read_config_rom will fail and get retried.
501  * It's better to start all over in this case because the node from which we
502  * are reading the ROM may have changed the ROM during the reset.
503  */
504 static int read_config_rom(struct fw_device *device, int generation)
505 {
506         const u32 *old_rom, *new_rom;
507         u32 *rom, *stack;
508         u32 sp, key;
509         int i, end, length, ret = -1;
510
511         rom = kmalloc(sizeof(*rom) * MAX_CONFIG_ROM_SIZE +
512                       sizeof(*stack) * MAX_CONFIG_ROM_SIZE, GFP_KERNEL);
513         if (rom == NULL)
514                 return -ENOMEM;
515
516         stack = &rom[MAX_CONFIG_ROM_SIZE];
517         memset(rom, 0, sizeof(*rom) * MAX_CONFIG_ROM_SIZE);
518
519         device->max_speed = SCODE_100;
520
521         /* First read the bus info block. */
522         for (i = 0; i < 5; i++) {
523                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
524                         goto out;
525                 /*
526                  * As per IEEE1212 7.2, during power-up, devices can
527                  * reply with a 0 for the first quadlet of the config
528                  * rom to indicate that they are booting (for example,
529                  * if the firmware is on the disk of a external
530                  * harddisk).  In that case we just fail, and the
531                  * retry mechanism will try again later.
532                  */
533                 if (i == 0 && rom[i] == 0)
534                         goto out;
535         }
536
537         device->max_speed = device->node->max_speed;
538
539         /*
540          * Determine the speed of
541          *   - devices with link speed less than PHY speed,
542          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
543          *   - all devices if there are 1394b repeaters.
544          * Note, we cannot use the bus info block's link_spd as starting point
545          * because some buggy firmwares set it lower than necessary and because
546          * 1394-1995 nodes do not have the field.
547          */
548         if ((rom[2] & 0x7) < device->max_speed ||
549             device->max_speed == SCODE_BETA ||
550             device->card->beta_repeaters_present) {
551                 u32 dummy;
552
553                 /* for S1600 and S3200 */
554                 if (device->max_speed == SCODE_BETA)
555                         device->max_speed = device->card->link_speed;
556
557                 while (device->max_speed > SCODE_100) {
558                         if (read_rom(device, generation, 0, &dummy) ==
559                             RCODE_COMPLETE)
560                                 break;
561                         device->max_speed--;
562                 }
563         }
564
565         /*
566          * Now parse the config rom.  The config rom is a recursive
567          * directory structure so we parse it using a stack of
568          * references to the blocks that make up the structure.  We
569          * push a reference to the root directory on the stack to
570          * start things off.
571          */
572         length = i;
573         sp = 0;
574         stack[sp++] = 0xc0000005;
575         while (sp > 0) {
576                 /*
577                  * Pop the next block reference of the stack.  The
578                  * lower 24 bits is the offset into the config rom,
579                  * the upper 8 bits are the type of the reference the
580                  * block.
581                  */
582                 key = stack[--sp];
583                 i = key & 0xffffff;
584                 if (WARN_ON(i >= MAX_CONFIG_ROM_SIZE))
585                         goto out;
586
587                 /* Read header quadlet for the block to get the length. */
588                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
589                         goto out;
590                 end = i + (rom[i] >> 16) + 1;
591                 if (end > MAX_CONFIG_ROM_SIZE) {
592                         /*
593                          * This block extends outside the config ROM which is
594                          * a firmware bug.  Ignore this whole block, i.e.
595                          * simply set a fake block length of 0.
596                          */
597                         fw_error("skipped invalid ROM block %x at %llx\n",
598                                  rom[i],
599                                  i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
600                         rom[i] = 0;
601                         end = i;
602                 }
603                 i++;
604
605                 /*
606                  * Now read in the block.  If this is a directory
607                  * block, check the entries as we read them to see if
608                  * it references another block, and push it in that case.
609                  */
610                 for (; i < end; i++) {
611                         if (read_rom(device, generation, i, &rom[i]) !=
612                             RCODE_COMPLETE)
613                                 goto out;
614
615                         if ((key >> 30) != 3 || (rom[i] >> 30) < 2)
616                                 continue;
617                         /*
618                          * Offset points outside the ROM.  May be a firmware
619                          * bug or an Extended ROM entry (IEEE 1212-2001 clause
620                          * 7.7.18).  Simply overwrite this pointer here by a
621                          * fake immediate entry so that later iterators over
622                          * the ROM don't have to check offsets all the time.
623                          */
624                         if (i + (rom[i] & 0xffffff) >= MAX_CONFIG_ROM_SIZE) {
625                                 fw_error("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                 goto out;
641
642         down_write(&fw_device_rwsem);
643         device->config_rom = new_rom;
644         device->config_rom_length = length;
645         up_write(&fw_device_rwsem);
646
647         kfree(old_rom);
648         ret = 0;
649         device->max_rec = rom[2] >> 12 & 0xf;
650         device->cmc     = rom[2] >> 30 & 1;
651         device->irmc    = rom[2] >> 31 & 1;
652  out:
653         kfree(rom);
654
655         return ret;
656 }
657
658 static void fw_unit_release(struct device *dev)
659 {
660         struct fw_unit *unit = fw_unit(dev);
661
662         kfree(unit);
663 }
664
665 static struct device_type fw_unit_type = {
666         .uevent         = fw_unit_uevent,
667         .release        = fw_unit_release,
668 };
669
670 static bool is_fw_unit(struct device *dev)
671 {
672         return dev->type == &fw_unit_type;
673 }
674
675 static void create_units(struct fw_device *device)
676 {
677         struct fw_csr_iterator ci;
678         struct fw_unit *unit;
679         int key, value, i;
680
681         i = 0;
682         fw_csr_iterator_init(&ci, &device->config_rom[5]);
683         while (fw_csr_iterator_next(&ci, &key, &value)) {
684                 if (key != (CSR_UNIT | CSR_DIRECTORY))
685                         continue;
686
687                 /*
688                  * Get the address of the unit directory and try to
689                  * match the drivers id_tables against it.
690                  */
691                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
692                 if (unit == NULL) {
693                         fw_error("failed to allocate memory for unit\n");
694                         continue;
695                 }
696
697                 unit->directory = ci.p + value - 1;
698                 unit->device.bus = &fw_bus_type;
699                 unit->device.type = &fw_unit_type;
700                 unit->device.parent = &device->device;
701                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
702
703                 BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
704                                 ARRAY_SIZE(fw_unit_attributes) +
705                                 ARRAY_SIZE(config_rom_attributes));
706                 init_fw_attribute_group(&unit->device,
707                                         fw_unit_attributes,
708                                         &unit->attribute_group);
709
710                 if (device_register(&unit->device) < 0)
711                         goto skip_unit;
712
713                 continue;
714
715         skip_unit:
716                 kfree(unit);
717         }
718 }
719
720 static int shutdown_unit(struct device *device, void *data)
721 {
722         device_unregister(device);
723
724         return 0;
725 }
726
727 /*
728  * fw_device_rwsem acts as dual purpose mutex:
729  *   - serializes accesses to fw_device_idr,
730  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
731  *     fw_unit.directory, unless those accesses happen at safe occasions
732  */
733 DECLARE_RWSEM(fw_device_rwsem);
734
735 DEFINE_IDR(fw_device_idr);
736 int fw_cdev_major;
737
738 struct fw_device *fw_device_get_by_devt(dev_t devt)
739 {
740         struct fw_device *device;
741
742         down_read(&fw_device_rwsem);
743         device = idr_find(&fw_device_idr, MINOR(devt));
744         if (device)
745                 fw_device_get(device);
746         up_read(&fw_device_rwsem);
747
748         return device;
749 }
750
751 /*
752  * These defines control the retry behavior for reading the config
753  * rom.  It shouldn't be necessary to tweak these; if the device
754  * doesn't respond to a config rom read within 10 seconds, it's not
755  * going to respond at all.  As for the initial delay, a lot of
756  * devices will be able to respond within half a second after bus
757  * reset.  On the other hand, it's not really worth being more
758  * aggressive than that, since it scales pretty well; if 10 devices
759  * are plugged in, they're all getting read within one second.
760  */
761
762 #define MAX_RETRIES     10
763 #define RETRY_DELAY     (3 * HZ)
764 #define INITIAL_DELAY   (HZ / 2)
765 #define SHUTDOWN_DELAY  (2 * HZ)
766
767 static void fw_device_shutdown(struct work_struct *work)
768 {
769         struct fw_device *device =
770                 container_of(work, struct fw_device, work.work);
771         int minor = MINOR(device->device.devt);
772
773         if (time_is_after_jiffies(device->card->reset_jiffies + SHUTDOWN_DELAY)
774             && !list_empty(&device->card->link)) {
775                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
776                 return;
777         }
778
779         if (atomic_cmpxchg(&device->state,
780                            FW_DEVICE_GONE,
781                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
782                 return;
783
784         fw_device_cdev_remove(device);
785         device_for_each_child(&device->device, NULL, shutdown_unit);
786         device_unregister(&device->device);
787
788         down_write(&fw_device_rwsem);
789         idr_remove(&fw_device_idr, minor);
790         up_write(&fw_device_rwsem);
791
792         fw_device_put(device);
793 }
794
795 static void fw_device_release(struct device *dev)
796 {
797         struct fw_device *device = fw_device(dev);
798         struct fw_card *card = device->card;
799         unsigned long flags;
800
801         /*
802          * Take the card lock so we don't set this to NULL while a
803          * FW_NODE_UPDATED callback is being handled or while the
804          * bus manager work looks at this node.
805          */
806         spin_lock_irqsave(&card->lock, flags);
807         device->node->data = NULL;
808         spin_unlock_irqrestore(&card->lock, flags);
809
810         fw_node_put(device->node);
811         kfree(device->config_rom);
812         kfree(device);
813         fw_card_put(card);
814 }
815
816 static struct device_type fw_device_type = {
817         .release = fw_device_release,
818 };
819
820 static bool is_fw_device(struct device *dev)
821 {
822         return dev->type == &fw_device_type;
823 }
824
825 static int update_unit(struct device *dev, void *data)
826 {
827         struct fw_unit *unit = fw_unit(dev);
828         struct fw_driver *driver = (struct fw_driver *)dev->driver;
829
830         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
831                 down(&dev->sem);
832                 driver->update(unit);
833                 up(&dev->sem);
834         }
835
836         return 0;
837 }
838
839 static void fw_device_update(struct work_struct *work)
840 {
841         struct fw_device *device =
842                 container_of(work, struct fw_device, work.work);
843
844         fw_device_cdev_update(device);
845         device_for_each_child(&device->device, NULL, update_unit);
846 }
847
848 /*
849  * If a device was pending for deletion because its node went away but its
850  * bus info block and root directory header matches that of a newly discovered
851  * device, revive the existing fw_device.
852  * The newly allocated fw_device becomes obsolete instead.
853  */
854 static int lookup_existing_device(struct device *dev, void *data)
855 {
856         struct fw_device *old = fw_device(dev);
857         struct fw_device *new = data;
858         struct fw_card *card = new->card;
859         int match = 0;
860
861         if (!is_fw_device(dev))
862                 return 0;
863
864         down_read(&fw_device_rwsem); /* serialize config_rom access */
865         spin_lock_irq(&card->lock);  /* serialize node access */
866
867         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
868             atomic_cmpxchg(&old->state,
869                            FW_DEVICE_GONE,
870                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
871                 struct fw_node *current_node = new->node;
872                 struct fw_node *obsolete_node = old->node;
873
874                 new->node = obsolete_node;
875                 new->node->data = new;
876                 old->node = current_node;
877                 old->node->data = old;
878
879                 old->max_speed = new->max_speed;
880                 old->node_id = current_node->node_id;
881                 smp_wmb();  /* update node_id before generation */
882                 old->generation = card->generation;
883                 old->config_rom_retries = 0;
884                 fw_notify("rediscovered device %s\n", dev_name(dev));
885
886                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
887                 schedule_delayed_work(&old->work, 0);
888
889                 if (current_node == card->root_node)
890                         fw_schedule_bm_work(card, 0);
891
892                 match = 1;
893         }
894
895         spin_unlock_irq(&card->lock);
896         up_read(&fw_device_rwsem);
897
898         return match;
899 }
900
901 enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
902
903 static void set_broadcast_channel(struct fw_device *device, int generation)
904 {
905         struct fw_card *card = device->card;
906         __be32 data;
907         int rcode;
908
909         if (!card->broadcast_channel_allocated)
910                 return;
911
912         /*
913          * The Broadcast_Channel Valid bit is required by nodes which want to
914          * transmit on this channel.  Such transmissions are practically
915          * exclusive to IP over 1394 (RFC 2734).  IP capable nodes are required
916          * to be IRM capable and have a max_rec of 8 or more.  We use this fact
917          * to narrow down to which nodes we send Broadcast_Channel updates.
918          */
919         if (!device->irmc || device->max_rec < 8)
920                 return;
921
922         /*
923          * Some 1394-1995 nodes crash if this 1394a-2000 register is written.
924          * Perform a read test first.
925          */
926         if (device->bc_implemented == BC_UNKNOWN) {
927                 rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
928                                 device->node_id, generation, device->max_speed,
929                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
930                                 &data, 4);
931                 switch (rcode) {
932                 case RCODE_COMPLETE:
933                         if (data & cpu_to_be32(1 << 31)) {
934                                 device->bc_implemented = BC_IMPLEMENTED;
935                                 break;
936                         }
937                         /* else fall through to case address error */
938                 case RCODE_ADDRESS_ERROR:
939                         device->bc_implemented = BC_UNIMPLEMENTED;
940                 }
941         }
942
943         if (device->bc_implemented == BC_IMPLEMENTED) {
944                 data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
945                                    BROADCAST_CHANNEL_VALID);
946                 fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
947                                 device->node_id, generation, device->max_speed,
948                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
949                                 &data, 4);
950         }
951 }
952
953 int fw_device_set_broadcast_channel(struct device *dev, void *gen)
954 {
955         if (is_fw_device(dev))
956                 set_broadcast_channel(fw_device(dev), (long)gen);
957
958         return 0;
959 }
960
961 static void fw_device_init(struct work_struct *work)
962 {
963         struct fw_device *device =
964                 container_of(work, struct fw_device, work.work);
965         struct device *revived_dev;
966         int minor, ret;
967
968         /*
969          * All failure paths here set node->data to NULL, so that we
970          * don't try to do device_for_each_child() on a kfree()'d
971          * device.
972          */
973
974         if (read_config_rom(device, device->generation) < 0) {
975                 if (device->config_rom_retries < MAX_RETRIES &&
976                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
977                         device->config_rom_retries++;
978                         schedule_delayed_work(&device->work, RETRY_DELAY);
979                 } else {
980                         fw_notify("giving up on config rom for node id %x\n",
981                                   device->node_id);
982                         if (device->node == device->card->root_node)
983                                 fw_schedule_bm_work(device->card, 0);
984                         fw_device_release(&device->device);
985                 }
986                 return;
987         }
988
989         revived_dev = device_find_child(device->card->device,
990                                         device, lookup_existing_device);
991         if (revived_dev) {
992                 put_device(revived_dev);
993                 fw_device_release(&device->device);
994
995                 return;
996         }
997
998         device_initialize(&device->device);
999
1000         fw_device_get(device);
1001         down_write(&fw_device_rwsem);
1002         ret = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
1003               idr_get_new(&fw_device_idr, device, &minor) :
1004               -ENOMEM;
1005         up_write(&fw_device_rwsem);
1006
1007         if (ret < 0)
1008                 goto error;
1009
1010         device->device.bus = &fw_bus_type;
1011         device->device.type = &fw_device_type;
1012         device->device.parent = device->card->device;
1013         device->device.devt = MKDEV(fw_cdev_major, minor);
1014         dev_set_name(&device->device, "fw%d", minor);
1015
1016         BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
1017                         ARRAY_SIZE(fw_device_attributes) +
1018                         ARRAY_SIZE(config_rom_attributes));
1019         init_fw_attribute_group(&device->device,
1020                                 fw_device_attributes,
1021                                 &device->attribute_group);
1022
1023         if (device_add(&device->device)) {
1024                 fw_error("Failed to add device.\n");
1025                 goto error_with_cdev;
1026         }
1027
1028         create_units(device);
1029
1030         /*
1031          * Transition the device to running state.  If it got pulled
1032          * out from under us while we did the intialization work, we
1033          * have to shut down the device again here.  Normally, though,
1034          * fw_node_event will be responsible for shutting it down when
1035          * necessary.  We have to use the atomic cmpxchg here to avoid
1036          * racing with the FW_NODE_DESTROYED case in
1037          * fw_node_event().
1038          */
1039         if (atomic_cmpxchg(&device->state,
1040                            FW_DEVICE_INITIALIZING,
1041                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
1042                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1043                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
1044         } else {
1045                 if (device->config_rom_retries)
1046                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
1047                                   "%d config ROM retries\n",
1048                                   dev_name(&device->device),
1049                                   device->config_rom[3], device->config_rom[4],
1050                                   1 << device->max_speed,
1051                                   device->config_rom_retries);
1052                 else
1053                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
1054                                   dev_name(&device->device),
1055                                   device->config_rom[3], device->config_rom[4],
1056                                   1 << device->max_speed);
1057                 device->config_rom_retries = 0;
1058
1059                 set_broadcast_channel(device, device->generation);
1060         }
1061
1062         /*
1063          * Reschedule the IRM work if we just finished reading the
1064          * root node config rom.  If this races with a bus reset we
1065          * just end up running the IRM work a couple of extra times -
1066          * pretty harmless.
1067          */
1068         if (device->node == device->card->root_node)
1069                 fw_schedule_bm_work(device->card, 0);
1070
1071         return;
1072
1073  error_with_cdev:
1074         down_write(&fw_device_rwsem);
1075         idr_remove(&fw_device_idr, minor);
1076         up_write(&fw_device_rwsem);
1077  error:
1078         fw_device_put(device);          /* fw_device_idr's reference */
1079
1080         put_device(&device->device);    /* our reference */
1081 }
1082
1083 enum {
1084         REREAD_BIB_ERROR,
1085         REREAD_BIB_GONE,
1086         REREAD_BIB_UNCHANGED,
1087         REREAD_BIB_CHANGED,
1088 };
1089
1090 /* Reread and compare bus info block and header of root directory */
1091 static int reread_config_rom(struct fw_device *device, int generation)
1092 {
1093         u32 q;
1094         int i;
1095
1096         for (i = 0; i < 6; i++) {
1097                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
1098                         return REREAD_BIB_ERROR;
1099
1100                 if (i == 0 && q == 0)
1101                         return REREAD_BIB_GONE;
1102
1103                 if (q != device->config_rom[i])
1104                         return REREAD_BIB_CHANGED;
1105         }
1106
1107         return REREAD_BIB_UNCHANGED;
1108 }
1109
1110 static void fw_device_refresh(struct work_struct *work)
1111 {
1112         struct fw_device *device =
1113                 container_of(work, struct fw_device, work.work);
1114         struct fw_card *card = device->card;
1115         int node_id = device->node_id;
1116
1117         switch (reread_config_rom(device, device->generation)) {
1118         case REREAD_BIB_ERROR:
1119                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
1120                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1121                         device->config_rom_retries++;
1122                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
1123
1124                         return;
1125                 }
1126                 goto give_up;
1127
1128         case REREAD_BIB_GONE:
1129                 goto gone;
1130
1131         case REREAD_BIB_UNCHANGED:
1132                 if (atomic_cmpxchg(&device->state,
1133                                    FW_DEVICE_INITIALIZING,
1134                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1135                         goto gone;
1136
1137                 fw_device_update(work);
1138                 device->config_rom_retries = 0;
1139                 goto out;
1140
1141         case REREAD_BIB_CHANGED:
1142                 break;
1143         }
1144
1145         /*
1146          * Something changed.  We keep things simple and don't investigate
1147          * further.  We just destroy all previous units and create new ones.
1148          */
1149         device_for_each_child(&device->device, NULL, shutdown_unit);
1150
1151         if (read_config_rom(device, device->generation) < 0) {
1152                 if (device->config_rom_retries < MAX_RETRIES &&
1153                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1154                         device->config_rom_retries++;
1155                         schedule_delayed_work(&device->work, RETRY_DELAY);
1156
1157                         return;
1158                 }
1159                 goto give_up;
1160         }
1161
1162         create_units(device);
1163
1164         /* Userspace may want to re-read attributes. */
1165         kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1166
1167         if (atomic_cmpxchg(&device->state,
1168                            FW_DEVICE_INITIALIZING,
1169                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1170                 goto gone;
1171
1172         fw_notify("refreshed device %s\n", dev_name(&device->device));
1173         device->config_rom_retries = 0;
1174         goto out;
1175
1176  give_up:
1177         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
1178  gone:
1179         atomic_set(&device->state, FW_DEVICE_GONE);
1180         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1181         schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
1182  out:
1183         if (node_id == card->root_node->node_id)
1184                 fw_schedule_bm_work(card, 0);
1185 }
1186
1187 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1188 {
1189         struct fw_device *device;
1190
1191         switch (event) {
1192         case FW_NODE_CREATED:
1193         case FW_NODE_LINK_ON:
1194                 if (!node->link_on)
1195                         break;
1196  create:
1197                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
1198                 if (device == NULL)
1199                         break;
1200
1201                 /*
1202                  * Do minimal intialization of the device here, the
1203                  * rest will happen in fw_device_init().
1204                  *
1205                  * Attention:  A lot of things, even fw_device_get(),
1206                  * cannot be done before fw_device_init() finished!
1207                  * You can basically just check device->state and
1208                  * schedule work until then, but only while holding
1209                  * card->lock.
1210                  */
1211                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1212                 device->card = fw_card_get(card);
1213                 device->node = fw_node_get(node);
1214                 device->node_id = node->node_id;
1215                 device->generation = card->generation;
1216                 device->is_local = node == card->local_node;
1217                 mutex_init(&device->client_list_mutex);
1218                 INIT_LIST_HEAD(&device->client_list);
1219
1220                 /*
1221                  * Set the node data to point back to this device so
1222                  * FW_NODE_UPDATED callbacks can update the node_id
1223                  * and generation for the device.
1224                  */
1225                 node->data = device;
1226
1227                 /*
1228                  * Many devices are slow to respond after bus resets,
1229                  * especially if they are bus powered and go through
1230                  * power-up after getting plugged in.  We schedule the
1231                  * first config rom scan half a second after bus reset.
1232                  */
1233                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1234                 schedule_delayed_work(&device->work, INITIAL_DELAY);
1235                 break;
1236
1237         case FW_NODE_INITIATED_RESET:
1238                 device = node->data;
1239                 if (device == NULL)
1240                         goto create;
1241
1242                 device->node_id = node->node_id;
1243                 smp_wmb();  /* update node_id before generation */
1244                 device->generation = card->generation;
1245                 if (atomic_cmpxchg(&device->state,
1246                             FW_DEVICE_RUNNING,
1247                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1248                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1249                         schedule_delayed_work(&device->work,
1250                                 device->is_local ? 0 : INITIAL_DELAY);
1251                 }
1252                 break;
1253
1254         case FW_NODE_UPDATED:
1255                 if (!node->link_on || node->data == NULL)
1256                         break;
1257
1258                 device = node->data;
1259                 device->node_id = node->node_id;
1260                 smp_wmb();  /* update node_id before generation */
1261                 device->generation = card->generation;
1262                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1263                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1264                         schedule_delayed_work(&device->work, 0);
1265                 }
1266                 break;
1267
1268         case FW_NODE_DESTROYED:
1269         case FW_NODE_LINK_OFF:
1270                 if (!node->data)
1271                         break;
1272
1273                 /*
1274                  * Destroy the device associated with the node.  There
1275                  * are two cases here: either the device is fully
1276                  * initialized (FW_DEVICE_RUNNING) or we're in the
1277                  * process of reading its config rom
1278                  * (FW_DEVICE_INITIALIZING).  If it is fully
1279                  * initialized we can reuse device->work to schedule a
1280                  * full fw_device_shutdown().  If not, there's work
1281                  * scheduled to read it's config rom, and we just put
1282                  * the device in shutdown state to have that code fail
1283                  * to create the device.
1284                  */
1285                 device = node->data;
1286                 if (atomic_xchg(&device->state,
1287                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1288                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1289                         schedule_delayed_work(&device->work,
1290                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1291                 }
1292                 break;
1293         }
1294 }