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