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