drivers/firewire/fw-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/module.h>
  22 #include <linux/wait.h>
  23 #include <linux/errno.h>
  24 #include <linux/kthread.h>
  25 #include <linux/device.h>
  26 #include <linux/delay.h>
  27 #include <linux/idr.h>
  28 #include <linux/string.h>
  29 #include <asm/semaphore.h>
  30 #include <asm/system.h>
  31 #include <linux/ctype.h>
  32 #include "fw-transaction.h"
  33 #include "fw-topology.h"
  34 #include "fw-device.h"
  35
  36 void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
  37 {
  38         ci->p = p + 1;
  39         ci->end = ci->p + (p[0] >> 16);
  40 }
  41 EXPORT_SYMBOL(fw_csr_iterator_init);
  42
  43 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
  44 {
  45         *key = *ci->p >> 24;
  46         *value = *ci->p & 0xffffff;
  47
  48         return ci->p++ < ci->end;
  49 }
  50 EXPORT_SYMBOL(fw_csr_iterator_next);
  51
  52 static int is_fw_unit(struct device *dev);
  53
  54 static int match_unit_directory(u32 * directory, const struct fw_device_id *id)
  55 {
  56         struct fw_csr_iterator ci;
  57         int key, value, match;
  58
  59         match = 0;
  60         fw_csr_iterator_init(&ci, directory);
  61         while (fw_csr_iterator_next(&ci, &key, &value)) {
  62                 if (key == CSR_VENDOR && value == id->vendor)
  63                         match |= FW_MATCH_VENDOR;
  64                 if (key == CSR_MODEL && value == id->model)
  65                         match |= FW_MATCH_MODEL;
  66                 if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
  67                         match |= FW_MATCH_SPECIFIER_ID;
  68                 if (key == CSR_VERSION && value == id->version)
  69                         match |= FW_MATCH_VERSION;
  70         }
  71
  72         return (match & id->match_flags) == id->match_flags;
  73 }
  74
  75 static int fw_unit_match(struct device *dev, struct device_driver *drv)
  76 {
  77         struct fw_unit *unit = fw_unit(dev);
  78         struct fw_driver *driver = fw_driver(drv);
  79         int i;
  80
  81         /* We only allow binding to fw_units. */
  82         if (!is_fw_unit(dev))
  83                 return 0;
  84
  85         for (i = 0; driver->id_table[i].match_flags != 0; i++) {
  86                 if (match_unit_directory(unit->directory, &driver->id_table[i]))
  87                         return 1;
  88         }
  89
  90         return 0;
  91 }
  92
  93 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
  94 {
  95         struct fw_device *device = fw_device(unit->device.parent);
  96         struct fw_csr_iterator ci;
  97
  98         int key, value;
  99         int vendor = 0;
 100         int model = 0;
 101         int specifier_id = 0;
 102         int version = 0;
 103
 104         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 105         while (fw_csr_iterator_next(&ci, &key, &value)) {
 106                 switch (key) {
 107                 case CSR_VENDOR:
 108                         vendor = value;
 109                         break;
 110                 case CSR_MODEL:
 111                         model = value;
 112                         break;
 113                 }
 114         }
 115
 116         fw_csr_iterator_init(&ci, unit->directory);
 117         while (fw_csr_iterator_next(&ci, &key, &value)) {
 118                 switch (key) {
 119                 case CSR_SPECIFIER_ID:
 120                         specifier_id = value;
 121                         break;
 122                 case CSR_VERSION:
 123                         version = value;
 124                         break;
 125                 }
 126         }
 127
 128         return snprintf(buffer, buffer_size,
 129                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
 130                         vendor, model, specifier_id, version);
 131 }
 132
 133 static int
 134 fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 135 {
 136         struct fw_unit *unit = fw_unit(dev);
 137         char modalias[64];
 138
 139         get_modalias(unit, modalias, sizeof(modalias));
 140
 141         if (add_uevent_var(env, "MODALIAS=%s", modalias))
 142                 return -ENOMEM;
 143
 144         return 0;
 145 }
 146
 147 struct bus_type fw_bus_type = {
 148         .name = "firewire",
 149         .match = fw_unit_match,
 150 };
 151 EXPORT_SYMBOL(fw_bus_type);
 152
 153 static void fw_device_release(struct device *dev)
 154 {
 155         struct fw_device *device = fw_device(dev);
 156         struct fw_card *card = device->card;
 157         unsigned long flags;
 158
 159         /*
 160          * Take the card lock so we don't set this to NULL while a
 161          * FW_NODE_UPDATED callback is being handled.
 162          */
 163         spin_lock_irqsave(&card->lock, flags);
 164         device->node->data = NULL;
 165         spin_unlock_irqrestore(&card->lock, flags);
 166
 167         fw_node_put(device->node);
 168         kfree(device->config_rom);
 169         kfree(device);
 170         atomic_dec(&card->device_count);
 171 }
 172
 173 int fw_device_enable_phys_dma(struct fw_device *device)
 174 {
 175         int generation = device->generation;
 176
 177         /* device->node_id, accessed below, must not be older than generation */
 178         smp_rmb();
 179
 180         return device->card->driver->enable_phys_dma(device->card,
 181                                                      device->node_id,
 182                                                      generation);
 183 }
 184 EXPORT_SYMBOL(fw_device_enable_phys_dma);
 185
 186 struct config_rom_attribute {
 187         struct device_attribute attr;
 188         u32 key;
 189 };
 190
 191 static ssize_t
 192 show_immediate(struct device *dev, struct device_attribute *dattr, char *buf)
 193 {
 194         struct config_rom_attribute *attr =
 195                 container_of(dattr, struct config_rom_attribute, attr);
 196         struct fw_csr_iterator ci;
 197         u32 *dir;
 198         int key, value, ret = -ENOENT;
 199
 200         down_read(&fw_device_rwsem);
 201
 202         if (is_fw_unit(dev))
 203                 dir = fw_unit(dev)->directory;
 204         else
 205                 dir = fw_device(dev)->config_rom + 5;
 206
 207         fw_csr_iterator_init(&ci, dir);
 208         while (fw_csr_iterator_next(&ci, &key, &value))
 209                 if (attr->key == key) {
 210                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
 211                                        "0x%06x\n", value);
 212                         break;
 213                 }
 214
 215         up_read(&fw_device_rwsem);
 216
 217         return ret;
 218 }
 219
 220 #define IMMEDIATE_ATTR(name, key)                               \
 221         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
 222
 223 static ssize_t
 224 show_text_leaf(struct device *dev, struct device_attribute *dattr, char *buf)
 225 {
 226         struct config_rom_attribute *attr =
 227                 container_of(dattr, struct config_rom_attribute, attr);
 228         struct fw_csr_iterator ci;
 229         u32 *dir, *block = NULL, *p, *end;
 230         int length, key, value, last_key = 0, ret = -ENOENT;
 231         char *b;
 232
 233         down_read(&fw_device_rwsem);
 234
 235         if (is_fw_unit(dev))
 236                 dir = fw_unit(dev)->directory;
 237         else
 238                 dir = fw_device(dev)->config_rom + 5;
 239
 240         fw_csr_iterator_init(&ci, dir);
 241         while (fw_csr_iterator_next(&ci, &key, &value)) {
 242                 if (attr->key == last_key &&
 243                     key == (CSR_DESCRIPTOR | CSR_LEAF))
 244                         block = ci.p - 1 + value;
 245                 last_key = key;
 246         }
 247
 248         if (block == NULL)
 249                 goto out;
 250
 251         length = min(block[0] >> 16, 256U);
 252         if (length < 3)
 253                 goto out;
 254
 255         if (block[1] != 0 || block[2] != 0)
 256                 /* Unknown encoding. */
 257                 goto out;
 258
 259         if (buf == NULL) {
 260                 ret = length * 4;
 261                 goto out;
 262         }
 263
 264         b = buf;
 265         end = &block[length + 1];
 266         for (p = &block[3]; p < end; p++, b += 4)
 267                 * (u32 *) b = (__force u32) __cpu_to_be32(*p);
 268
 269         /* Strip trailing whitespace and add newline. */
 270         while (b--, (isspace(*b) || *b == '\0') && b > buf);
 271         strcpy(b + 1, "\n");
 272         ret = b + 2 - buf;
 273  out:
 274         up_read(&fw_device_rwsem);
 275
 276         return ret;
 277 }
 278
 279 #define TEXT_LEAF_ATTR(name, key)                               \
 280         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
 281
 282 static struct config_rom_attribute config_rom_attributes[] = {
 283         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
 284         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
 285         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
 286         IMMEDIATE_ATTR(version, CSR_VERSION),
 287         IMMEDIATE_ATTR(model, CSR_MODEL),
 288         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
 289         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
 290         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
 291 };
 292
 293 static void
 294 init_fw_attribute_group(struct device *dev,
 295                         struct device_attribute *attrs,
 296                         struct fw_attribute_group *group)
 297 {
 298         struct device_attribute *attr;
 299         int i, j;
 300
 301         for (j = 0; attrs[j].attr.name != NULL; j++)
 302                 group->attrs[j] = &attrs[j].attr;
 303
 304         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
 305                 attr = &config_rom_attributes[i].attr;
 306                 if (attr->show(dev, attr, NULL) < 0)
 307                         continue;
 308                 group->attrs[j++] = &attr->attr;
 309         }
 310
 311         BUG_ON(j >= ARRAY_SIZE(group->attrs));
 312         group->attrs[j++] = NULL;
 313         group->groups[0] = &group->group;
 314         group->groups[1] = NULL;
 315         group->group.attrs = group->attrs;
 316         dev->groups = group->groups;
 317 }
 318
 319 static ssize_t
 320 modalias_show(struct device *dev,
 321               struct device_attribute *attr, char *buf)
 322 {
 323         struct fw_unit *unit = fw_unit(dev);
 324         int length;
 325
 326         length = get_modalias(unit, buf, PAGE_SIZE);
 327         strcpy(buf + length, "\n");
 328
 329         return length + 1;
 330 }
 331
 332 static ssize_t
 333 rom_index_show(struct device *dev,
 334                struct device_attribute *attr, char *buf)
 335 {
 336         struct fw_device *device = fw_device(dev->parent);
 337         struct fw_unit *unit = fw_unit(dev);
 338
 339         return snprintf(buf, PAGE_SIZE, "%d\n",
 340                         (int)(unit->directory - device->config_rom));
 341 }
 342
 343 static struct device_attribute fw_unit_attributes[] = {
 344         __ATTR_RO(modalias),
 345         __ATTR_RO(rom_index),
 346         __ATTR_NULL,
 347 };
 348
 349 static ssize_t
 350 config_rom_show(struct device *dev, struct device_attribute *attr, char *buf)
 351 {
 352         struct fw_device *device = fw_device(dev);
 353         size_t length;
 354
 355         down_read(&fw_device_rwsem);
 356         length = device->config_rom_length * 4;
 357         memcpy(buf, device->config_rom, length);
 358         up_read(&fw_device_rwsem);
 359
 360         return length;
 361 }
 362
 363 static ssize_t
 364 guid_show(struct device *dev, struct device_attribute *attr, char *buf)
 365 {
 366         struct fw_device *device = fw_device(dev);
 367         int ret;
 368
 369         down_read(&fw_device_rwsem);
 370         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
 371                        device->config_rom[3], device->config_rom[4]);
 372         up_read(&fw_device_rwsem);
 373
 374         return ret;
 375 }
 376
 377 static struct device_attribute fw_device_attributes[] = {
 378         __ATTR_RO(config_rom),
 379         __ATTR_RO(guid),
 380         __ATTR_NULL,
 381 };
 382
 383 struct read_quadlet_callback_data {
 384         struct completion done;
 385         int rcode;
 386         u32 data;
 387 };
 388
 389 static void
 390 complete_transaction(struct fw_card *card, int rcode,
 391                      void *payload, size_t length, void *data)
 392 {
 393         struct read_quadlet_callback_data *callback_data = data;
 394
 395         if (rcode == RCODE_COMPLETE)
 396                 callback_data->data = be32_to_cpu(*(__be32 *)payload);
 397         callback_data->rcode = rcode;
 398         complete(&callback_data->done);
 399 }
 400
 401 static int
 402 read_rom(struct fw_device *device, int generation, int index, u32 *data)
 403 {
 404         struct read_quadlet_callback_data callback_data;
 405         struct fw_transaction t;
 406         u64 offset;
 407
 408         /* device->node_id, accessed below, must not be older than generation */
 409         smp_rmb();
 410
 411         init_completion(&callback_data.done);
 412
 413         offset = (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4;
 414         fw_send_request(device->card, &t, TCODE_READ_QUADLET_REQUEST,
 415                         device->node_id, generation, device->max_speed,
 416                         offset, NULL, 4, complete_transaction, &callback_data);
 417
 418         wait_for_completion(&callback_data.done);
 419
 420         *data = callback_data.data;
 421
 422         return callback_data.rcode;
 423 }
 424
 425 #define READ_BIB_ROM_SIZE       256
 426 #define READ_BIB_STACK_SIZE     16
 427
 428 /*
 429  * Read the bus info block, perform a speed probe, and read all of the rest of
 430  * the config ROM.  We do all this with a cached bus generation.  If the bus
 431  * generation changes under us, read_bus_info_block will fail and get retried.
 432  * It's better to start all over in this case because the node from which we
 433  * are reading the ROM may have changed the ROM during the reset.
 434  */
 435 static int read_bus_info_block(struct fw_device *device, int generation)
 436 {
 437         u32 *rom, *stack, *old_rom, *new_rom;
 438         u32 sp, key;
 439         int i, end, length, ret = -1;
 440
 441         rom = kmalloc(sizeof(*rom) * READ_BIB_ROM_SIZE +
 442                       sizeof(*stack) * READ_BIB_STACK_SIZE, GFP_KERNEL);
 443         if (rom == NULL)
 444                 return -ENOMEM;
 445
 446         stack = &rom[READ_BIB_ROM_SIZE];
 447
 448         device->max_speed = SCODE_100;
 449
 450         /* First read the bus info block. */
 451         for (i = 0; i < 5; i++) {
 452                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 453                         goto out;
 454                 /*
 455                  * As per IEEE1212 7.2, during power-up, devices can
 456                  * reply with a 0 for the first quadlet of the config
 457                  * rom to indicate that they are booting (for example,
 458                  * if the firmware is on the disk of a external
 459                  * harddisk).  In that case we just fail, and the
 460                  * retry mechanism will try again later.
 461                  */
 462                 if (i == 0 && rom[i] == 0)
 463                         goto out;
 464         }
 465
 466         device->max_speed = device->node->max_speed;
 467
 468         /*
 469          * Determine the speed of
 470          *   - devices with link speed less than PHY speed,
 471          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
 472          *   - all devices if there are 1394b repeaters.
 473          * Note, we cannot use the bus info block's link_spd as starting point
 474          * because some buggy firmwares set it lower than necessary and because
 475          * 1394-1995 nodes do not have the field.
 476          */
 477         if ((rom[2] & 0x7) < device->max_speed ||
 478             device->max_speed == SCODE_BETA ||
 479             device->card->beta_repeaters_present) {
 480                 u32 dummy;
 481
 482                 /* for S1600 and S3200 */
 483                 if (device->max_speed == SCODE_BETA)
 484                         device->max_speed = device->card->link_speed;
 485
 486                 while (device->max_speed > SCODE_100) {
 487                         if (read_rom(device, generation, 0, &dummy) ==
 488                             RCODE_COMPLETE)
 489                                 break;
 490                         device->max_speed--;
 491                 }
 492         }
 493
 494         /*
 495          * Now parse the config rom.  The config rom is a recursive
 496          * directory structure so we parse it using a stack of
 497          * references to the blocks that make up the structure.  We
 498          * push a reference to the root directory on the stack to
 499          * start things off.
 500          */
 501         length = i;
 502         sp = 0;
 503         stack[sp++] = 0xc0000005;
 504         while (sp > 0) {
 505                 /*
 506                  * Pop the next block reference of the stack.  The
 507                  * lower 24 bits is the offset into the config rom,
 508                  * the upper 8 bits are the type of the reference the
 509                  * block.
 510                  */
 511                 key = stack[--sp];
 512                 i = key & 0xffffff;
 513                 if (i >= READ_BIB_ROM_SIZE)
 514                         /*
 515                          * The reference points outside the standard
 516                          * config rom area, something's fishy.
 517                          */
 518                         goto out;
 519
 520                 /* Read header quadlet for the block to get the length. */
 521                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 522                         goto out;
 523                 end = i + (rom[i] >> 16) + 1;
 524                 i++;
 525                 if (end > READ_BIB_ROM_SIZE)
 526                         /*
 527                          * This block extends outside standard config
 528                          * area (and the array we're reading it
 529                          * into).  That's broken, so ignore this
 530                          * device.
 531                          */
 532                         goto out;
 533
 534                 /*
 535                  * Now read in the block.  If this is a directory
 536                  * block, check the entries as we read them to see if
 537                  * it references another block, and push it in that case.
 538                  */
 539                 while (i < end) {
 540                         if (read_rom(device, generation, i, &rom[i]) !=
 541                             RCODE_COMPLETE)
 542                                 goto out;
 543                         if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
 544                             sp < READ_BIB_STACK_SIZE)
 545                                 stack[sp++] = i + rom[i];
 546                         i++;
 547                 }
 548                 if (length < i)
 549                         length = i;
 550         }
 551
 552         old_rom = device->config_rom;
 553         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
 554         if (new_rom == NULL)
 555                 goto out;
 556
 557         down_write(&fw_device_rwsem);
 558         device->config_rom = new_rom;
 559         device->config_rom_length = length;
 560         up_write(&fw_device_rwsem);
 561
 562         kfree(old_rom);
 563         ret = 0;
 564         device->cmc = rom[2] & 1 << 30;
 565  out:
 566         kfree(rom);
 567
 568         return ret;
 569 }
 570
 571 static void fw_unit_release(struct device *dev)
 572 {
 573         struct fw_unit *unit = fw_unit(dev);
 574
 575         kfree(unit);
 576 }
 577
 578 static struct device_type fw_unit_type = {
 579         .uevent         = fw_unit_uevent,
 580         .release        = fw_unit_release,
 581 };
 582
 583 static int is_fw_unit(struct device *dev)
 584 {
 585         return dev->type == &fw_unit_type;
 586 }
 587
 588 static void create_units(struct fw_device *device)
 589 {
 590         struct fw_csr_iterator ci;
 591         struct fw_unit *unit;
 592         int key, value, i;
 593
 594         i = 0;
 595         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 596         while (fw_csr_iterator_next(&ci, &key, &value)) {
 597                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 598                         continue;
 599
 600                 /*
 601                  * Get the address of the unit directory and try to
 602                  * match the drivers id_tables against it.
 603                  */
 604                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 605                 if (unit == NULL) {
 606                         fw_error("failed to allocate memory for unit\n");
 607                         continue;
 608                 }
 609
 610                 unit->directory = ci.p + value - 1;
 611                 unit->device.bus = &fw_bus_type;
 612                 unit->device.type = &fw_unit_type;
 613                 unit->device.parent = &device->device;
 614                 snprintf(unit->device.bus_id, sizeof(unit->device.bus_id),
 615                          "%s.%d", device->device.bus_id, i++);
 616
 617                 init_fw_attribute_group(&unit->device,
 618                                         fw_unit_attributes,
 619                                         &unit->attribute_group);
 620                 if (device_register(&unit->device) < 0)
 621                         goto skip_unit;
 622
 623                 continue;
 624
 625         skip_unit:
 626                 kfree(unit);
 627         }
 628 }
 629
 630 static int shutdown_unit(struct device *device, void *data)
 631 {
 632         device_unregister(device);
 633
 634         return 0;
 635 }
 636
 637 /*
 638  * fw_device_rwsem acts as dual purpose mutex:
 639  *   - serializes accesses to fw_device_idr,
 640  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 641  *     fw_unit.directory, unless those accesses happen at safe occasions
 642  */
 643 DECLARE_RWSEM(fw_device_rwsem);
 644
 645 static DEFINE_IDR(fw_device_idr);
 646 int fw_cdev_major;
 647
 648 struct fw_device *fw_device_get_by_devt(dev_t devt)
 649 {
 650         struct fw_device *device;
 651
 652         down_read(&fw_device_rwsem);
 653         device = idr_find(&fw_device_idr, MINOR(devt));
 654         if (device)
 655                 fw_device_get(device);
 656         up_read(&fw_device_rwsem);
 657
 658         return device;
 659 }
 660
 661 static void fw_device_shutdown(struct work_struct *work)
 662 {
 663         struct fw_device *device =
 664                 container_of(work, struct fw_device, work.work);
 665         int minor = MINOR(device->device.devt);
 666
 667         fw_device_cdev_remove(device);
 668         device_for_each_child(&device->device, NULL, shutdown_unit);
 669         device_unregister(&device->device);
 670
 671         down_write(&fw_device_rwsem);
 672         idr_remove(&fw_device_idr, minor);
 673         up_write(&fw_device_rwsem);
 674         fw_device_put(device);
 675 }
 676
 677 static struct device_type fw_device_type = {
 678         .release        = fw_device_release,
 679 };
 680
 681 /*
 682  * These defines control the retry behavior for reading the config
 683  * rom.  It shouldn't be necessary to tweak these; if the device
 684  * doesn't respond to a config rom read within 10 seconds, it's not
 685  * going to respond at all.  As for the initial delay, a lot of
 686  * devices will be able to respond within half a second after bus
 687  * reset.  On the other hand, it's not really worth being more
 688  * aggressive than that, since it scales pretty well; if 10 devices
 689  * are plugged in, they're all getting read within one second.
 690  */
 691
 692 #define MAX_RETRIES     10
 693 #define RETRY_DELAY     (3 * HZ)
 694 #define INITIAL_DELAY   (HZ / 2)
 695
 696 static void fw_device_init(struct work_struct *work)
 697 {
 698         struct fw_device *device =
 699                 container_of(work, struct fw_device, work.work);
 700         int minor, err;
 701
 702         /*
 703          * All failure paths here set node->data to NULL, so that we
 704          * don't try to do device_for_each_child() on a kfree()'d
 705          * device.
 706          */
 707
 708         if (read_bus_info_block(device, device->generation) < 0) {
 709                 if (device->config_rom_retries < MAX_RETRIES &&
 710                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 711                         device->config_rom_retries++;
 712                         schedule_delayed_work(&device->work, RETRY_DELAY);
 713                 } else {
 714                         fw_notify("giving up on config rom for node id %x\n",
 715                                   device->node_id);
 716                         if (device->node == device->card->root_node)
 717                                 schedule_delayed_work(&device->card->work, 0);
 718                         fw_device_release(&device->device);
 719                 }
 720                 return;
 721         }
 722
 723         err = -ENOMEM;
 724
 725         fw_device_get(device);
 726         down_write(&fw_device_rwsem);
 727         if (idr_pre_get(&fw_device_idr, GFP_KERNEL))
 728                 err = idr_get_new(&fw_device_idr, device, &minor);
 729         up_write(&fw_device_rwsem);
 730
 731         if (err < 0)
 732                 goto error;
 733
 734         device->device.bus = &fw_bus_type;
 735         device->device.type = &fw_device_type;
 736         device->device.parent = device->card->device;
 737         device->device.devt = MKDEV(fw_cdev_major, minor);
 738         snprintf(device->device.bus_id, sizeof(device->device.bus_id),
 739                  "fw%d", minor);
 740
 741         init_fw_attribute_group(&device->device,
 742                                 fw_device_attributes,
 743                                 &device->attribute_group);
 744         if (device_add(&device->device)) {
 745                 fw_error("Failed to add device.\n");
 746                 goto error_with_cdev;
 747         }
 748
 749         create_units(device);
 750
 751         /*
 752          * Transition the device to running state.  If it got pulled
 753          * out from under us while we did the intialization work, we
 754          * have to shut down the device again here.  Normally, though,
 755          * fw_node_event will be responsible for shutting it down when
 756          * necessary.  We have to use the atomic cmpxchg here to avoid
 757          * racing with the FW_NODE_DESTROYED case in
 758          * fw_node_event().
 759          */
 760         if (atomic_cmpxchg(&device->state,
 761                     FW_DEVICE_INITIALIZING,
 762                     FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN) {
 763                 fw_device_shutdown(work);
 764         } else {
 765                 if (device->config_rom_retries)
 766                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
 767                                   "%d config ROM retries\n",
 768                                   device->device.bus_id,
 769                                   device->config_rom[3], device->config_rom[4],
 770                                   1 << device->max_speed,
 771                                   device->config_rom_retries);
 772                 else
 773                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
 774                                   device->device.bus_id,
 775                                   device->config_rom[3], device->config_rom[4],
 776                                   1 << device->max_speed);
 777                 device->config_rom_retries = 0;
 778         }
 779
 780         /*
 781          * Reschedule the IRM work if we just finished reading the
 782          * root node config rom.  If this races with a bus reset we
 783          * just end up running the IRM work a couple of extra times -
 784          * pretty harmless.
 785          */
 786         if (device->node == device->card->root_node)
 787                 schedule_delayed_work(&device->card->work, 0);
 788
 789         return;
 790
 791  error_with_cdev:
 792         down_write(&fw_device_rwsem);
 793         idr_remove(&fw_device_idr, minor);
 794         up_write(&fw_device_rwsem);
 795  error:
 796         fw_device_put(device);          /* fw_device_idr's reference */
 797
 798         put_device(&device->device);    /* our reference */
 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                 down(&dev->sem);
 808                 driver->update(unit);
 809                 up(&dev->sem);
 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 enum {
 825         REREAD_BIB_ERROR,
 826         REREAD_BIB_GONE,
 827         REREAD_BIB_UNCHANGED,
 828         REREAD_BIB_CHANGED,
 829 };
 830
 831 /* Reread and compare bus info block and header of root directory */
 832 static int reread_bus_info_block(struct fw_device *device, int generation)
 833 {
 834         u32 q;
 835         int i;
 836
 837         for (i = 0; i < 6; i++) {
 838                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
 839                         return REREAD_BIB_ERROR;
 840
 841                 if (i == 0 && q == 0)
 842                         return REREAD_BIB_GONE;
 843
 844                 if (i > device->config_rom_length || q != device->config_rom[i])
 845                         return REREAD_BIB_CHANGED;
 846         }
 847
 848         return REREAD_BIB_UNCHANGED;
 849 }
 850
 851 static void fw_device_refresh(struct work_struct *work)
 852 {
 853         struct fw_device *device =
 854                 container_of(work, struct fw_device, work.work);
 855         struct fw_card *card = device->card;
 856         int node_id = device->node_id;
 857
 858         switch (reread_bus_info_block(device, device->generation)) {
 859         case REREAD_BIB_ERROR:
 860                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
 861                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 862                         device->config_rom_retries++;
 863                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
 864
 865                         return;
 866                 }
 867                 goto give_up;
 868
 869         case REREAD_BIB_GONE:
 870                 goto gone;
 871
 872         case REREAD_BIB_UNCHANGED:
 873                 if (atomic_cmpxchg(&device->state,
 874                             FW_DEVICE_INITIALIZING,
 875                             FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
 876                         goto gone;
 877
 878                 fw_device_update(work);
 879                 device->config_rom_retries = 0;
 880                 goto out;
 881
 882         case REREAD_BIB_CHANGED:
 883                 break;
 884         }
 885
 886         /*
 887          * Something changed.  We keep things simple and don't investigate
 888          * further.  We just destroy all previous units and create new ones.
 889          */
 890         device_for_each_child(&device->device, NULL, shutdown_unit);
 891
 892         if (read_bus_info_block(device, device->generation) < 0) {
 893                 if (device->config_rom_retries < MAX_RETRIES &&
 894                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 895                         device->config_rom_retries++;
 896                         schedule_delayed_work(&device->work, RETRY_DELAY);
 897
 898                         return;
 899                 }
 900                 goto give_up;
 901         }
 902
 903         create_units(device);
 904
 905         if (atomic_cmpxchg(&device->state,
 906                     FW_DEVICE_INITIALIZING,
 907                     FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
 908                 goto gone;
 909
 910         fw_notify("refreshed device %s\n", device->device.bus_id);
 911         device->config_rom_retries = 0;
 912         goto out;
 913
 914  give_up:
 915         fw_notify("giving up on refresh of device %s\n", device->device.bus_id);
 916  gone:
 917         atomic_set(&device->state, FW_DEVICE_SHUTDOWN);
 918         fw_device_shutdown(work);
 919  out:
 920         if (node_id == card->root_node->node_id)
 921                 schedule_delayed_work(&card->work, 0);
 922 }
 923
 924 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
 925 {
 926         struct fw_device *device;
 927
 928         switch (event) {
 929         case FW_NODE_CREATED:
 930         case FW_NODE_LINK_ON:
 931                 if (!node->link_on)
 932                         break;
 933  create:
 934                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
 935                 if (device == NULL)
 936                         break;
 937
 938                 /*
 939                  * Do minimal intialization of the device here, the
 940                  * rest will happen in fw_device_init().  We need the
 941                  * card and node so we can read the config rom and we
 942                  * need to do device_initialize() now so
 943                  * device_for_each_child() in FW_NODE_UPDATED is
 944                  * doesn't freak out.
 945                  */
 946                 device_initialize(&device->device);
 947                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
 948                 atomic_inc(&card->device_count);
 949                 device->card = card;
 950                 device->node = fw_node_get(node);
 951                 device->node_id = node->node_id;
 952                 device->generation = card->generation;
 953                 INIT_LIST_HEAD(&device->client_list);
 954
 955                 /*
 956                  * Set the node data to point back to this device so
 957                  * FW_NODE_UPDATED callbacks can update the node_id
 958                  * and generation for the device.
 959                  */
 960                 node->data = device;
 961
 962                 /*
 963                  * Many devices are slow to respond after bus resets,
 964                  * especially if they are bus powered and go through
 965                  * power-up after getting plugged in.  We schedule the
 966                  * first config rom scan half a second after bus reset.
 967                  */
 968                 INIT_DELAYED_WORK(&device->work, fw_device_init);
 969                 schedule_delayed_work(&device->work, INITIAL_DELAY);
 970                 break;
 971
 972         case FW_NODE_INITIATED_RESET:
 973                 device = node->data;
 974                 if (device == NULL)
 975                         goto create;
 976
 977                 device->node_id = node->node_id;
 978                 smp_wmb();  /* update node_id before generation */
 979                 device->generation = card->generation;
 980                 if (atomic_cmpxchg(&device->state,
 981                             FW_DEVICE_RUNNING,
 982                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
 983                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
 984                         schedule_delayed_work(&device->work,
 985                                 node == card->local_node ? 0 : INITIAL_DELAY);
 986                 }
 987                 break;
 988
 989         case FW_NODE_UPDATED:
 990                 if (!node->link_on || node->data == NULL)
 991                         break;
 992
 993                 device = node->data;
 994                 device->node_id = node->node_id;
 995                 smp_wmb();  /* update node_id before generation */
 996                 device->generation = card->generation;
 997                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
 998                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
 999                         schedule_delayed_work(&device->work, 0);
1000                 }
1001                 break;
1002
1003         case FW_NODE_DESTROYED:
1004         case FW_NODE_LINK_OFF:
1005                 if (!node->data)
1006                         break;
1007
1008                 /*
1009                  * Destroy the device associated with the node.  There
1010                  * are two cases here: either the device is fully
1011                  * initialized (FW_DEVICE_RUNNING) or we're in the
1012                  * process of reading its config rom
1013                  * (FW_DEVICE_INITIALIZING).  If it is fully
1014                  * initialized we can reuse device->work to schedule a
1015                  * full fw_device_shutdown().  If not, there's work
1016                  * scheduled to read it's config rom, and we just put
1017                  * the device in shutdown state to have that code fail
1018                  * to create the device.
1019                  */
1020                 device = node->data;
1021                 if (atomic_xchg(&device->state,
1022                                 FW_DEVICE_SHUTDOWN) == FW_DEVICE_RUNNING) {
1023                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1024                         schedule_delayed_work(&device->work, 0);
1025                 }
1026                 break;
1027         }
1028 }