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 <linux/rwsem.h>
  30 #include <linux/semaphore.h>
  31 #include <asm/system.h>
  32 #include <linux/ctype.h>
  33 #include "fw-transaction.h"
  34 #include "fw-topology.h"
  35 #include "fw-device.h"
  36
  37 void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
  38 {
  39         ci->p = p + 1;
  40         ci->end = ci->p + (p[0] >> 16);
  41 }
  42 EXPORT_SYMBOL(fw_csr_iterator_init);
  43
  44 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
  45 {
  46         *key = *ci->p >> 24;
  47         *value = *ci->p & 0xffffff;
  48
  49         return ci->p++ < ci->end;
  50 }
  51 EXPORT_SYMBOL(fw_csr_iterator_next);
  52
  53 static int is_fw_unit(struct device *dev);
  54
  55 static int match_unit_directory(u32 * directory, const struct fw_device_id *id)
  56 {
  57         struct fw_csr_iterator ci;
  58         int key, value, match;
  59
  60         match = 0;
  61         fw_csr_iterator_init(&ci, directory);
  62         while (fw_csr_iterator_next(&ci, &key, &value)) {
  63                 if (key == CSR_VENDOR && value == id->vendor)
  64                         match |= FW_MATCH_VENDOR;
  65                 if (key == CSR_MODEL && value == id->model)
  66                         match |= FW_MATCH_MODEL;
  67                 if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
  68                         match |= FW_MATCH_SPECIFIER_ID;
  69                 if (key == CSR_VERSION && value == id->version)
  70                         match |= FW_MATCH_VERSION;
  71         }
  72
  73         return (match & id->match_flags) == id->match_flags;
  74 }
  75
  76 static int fw_unit_match(struct device *dev, struct device_driver *drv)
  77 {
  78         struct fw_unit *unit = fw_unit(dev);
  79         struct fw_driver *driver = fw_driver(drv);
  80         int i;
  81
  82         /* We only allow binding to fw_units. */
  83         if (!is_fw_unit(dev))
  84                 return 0;
  85
  86         for (i = 0; driver->id_table[i].match_flags != 0; i++) {
  87                 if (match_unit_directory(unit->directory, &driver->id_table[i]))
  88                         return 1;
  89         }
  90
  91         return 0;
  92 }
  93
  94 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
  95 {
  96         struct fw_device *device = fw_device(unit->device.parent);
  97         struct fw_csr_iterator ci;
  98
  99         int key, value;
 100         int vendor = 0;
 101         int model = 0;
 102         int specifier_id = 0;
 103         int version = 0;
 104
 105         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 106         while (fw_csr_iterator_next(&ci, &key, &value)) {
 107                 switch (key) {
 108                 case CSR_VENDOR:
 109                         vendor = value;
 110                         break;
 111                 case CSR_MODEL:
 112                         model = value;
 113                         break;
 114                 }
 115         }
 116
 117         fw_csr_iterator_init(&ci, unit->directory);
 118         while (fw_csr_iterator_next(&ci, &key, &value)) {
 119                 switch (key) {
 120                 case CSR_SPECIFIER_ID:
 121                         specifier_id = value;
 122                         break;
 123                 case CSR_VERSION:
 124                         version = value;
 125                         break;
 126                 }
 127         }
 128
 129         return snprintf(buffer, buffer_size,
 130                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
 131                         vendor, model, specifier_id, version);
 132 }
 133
 134 static int
 135 fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 136 {
 137         struct fw_unit *unit = fw_unit(dev);
 138         char modalias[64];
 139
 140         get_modalias(unit, modalias, sizeof(modalias));
 141
 142         if (add_uevent_var(env, "MODALIAS=%s", modalias))
 143                 return -ENOMEM;
 144
 145         return 0;
 146 }
 147
 148 struct bus_type fw_bus_type = {
 149         .name = "firewire",
 150         .match = fw_unit_match,
 151 };
 152 EXPORT_SYMBOL(fw_bus_type);
 153
 154 static void fw_device_release(struct device *dev)
 155 {
 156         struct fw_device *device = fw_device(dev);
 157         struct fw_card *card = device->card;
 158         unsigned long flags;
 159
 160         /*
 161          * Take the card lock so we don't set this to NULL while a
 162          * FW_NODE_UPDATED callback is being handled.
 163          */
 164         spin_lock_irqsave(&card->lock, flags);
 165         device->node->data = NULL;
 166         spin_unlock_irqrestore(&card->lock, flags);
 167
 168         fw_node_put(device->node);
 169         kfree(device->config_rom);
 170         kfree(device);
 171         atomic_dec(&card->device_count);
 172 }
 173
 174 int fw_device_enable_phys_dma(struct fw_device *device)
 175 {
 176         int generation = device->generation;
 177
 178         /* device->node_id, accessed below, must not be older than generation */
 179         smp_rmb();
 180
 181         return device->card->driver->enable_phys_dma(device->card,
 182                                                      device->node_id,
 183                                                      generation);
 184 }
 185 EXPORT_SYMBOL(fw_device_enable_phys_dma);
 186
 187 struct config_rom_attribute {
 188         struct device_attribute attr;
 189         u32 key;
 190 };
 191
 192 static ssize_t
 193 show_immediate(struct device *dev, struct device_attribute *dattr, char *buf)
 194 {
 195         struct config_rom_attribute *attr =
 196                 container_of(dattr, struct config_rom_attribute, attr);
 197         struct fw_csr_iterator ci;
 198         u32 *dir;
 199         int key, value, ret = -ENOENT;
 200
 201         down_read(&fw_device_rwsem);
 202
 203         if (is_fw_unit(dev))
 204                 dir = fw_unit(dev)->directory;
 205         else
 206                 dir = fw_device(dev)->config_rom + 5;
 207
 208         fw_csr_iterator_init(&ci, dir);
 209         while (fw_csr_iterator_next(&ci, &key, &value))
 210                 if (attr->key == key) {
 211                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
 212                                        "0x%06x\n", value);
 213                         break;
 214                 }
 215
 216         up_read(&fw_device_rwsem);
 217
 218         return ret;
 219 }
 220
 221 #define IMMEDIATE_ATTR(name, key)                               \
 222         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
 223
 224 static ssize_t
 225 show_text_leaf(struct device *dev, struct device_attribute *dattr, char *buf)
 226 {
 227         struct config_rom_attribute *attr =
 228                 container_of(dattr, struct config_rom_attribute, attr);
 229         struct fw_csr_iterator ci;
 230         u32 *dir, *block = NULL, *p, *end;
 231         int length, key, value, last_key = 0, ret = -ENOENT;
 232         char *b;
 233
 234         down_read(&fw_device_rwsem);
 235
 236         if (is_fw_unit(dev))
 237                 dir = fw_unit(dev)->directory;
 238         else
 239                 dir = fw_device(dev)->config_rom + 5;
 240
 241         fw_csr_iterator_init(&ci, dir);
 242         while (fw_csr_iterator_next(&ci, &key, &value)) {
 243                 if (attr->key == last_key &&
 244                     key == (CSR_DESCRIPTOR | CSR_LEAF))
 245                         block = ci.p - 1 + value;
 246                 last_key = key;
 247         }
 248
 249         if (block == NULL)
 250                 goto out;
 251
 252         length = min(block[0] >> 16, 256U);
 253         if (length < 3)
 254                 goto out;
 255
 256         if (block[1] != 0 || block[2] != 0)
 257                 /* Unknown encoding. */
 258                 goto out;
 259
 260         if (buf == NULL) {
 261                 ret = length * 4;
 262                 goto out;
 263         }
 264
 265         b = buf;
 266         end = &block[length + 1];
 267         for (p = &block[3]; p < end; p++, b += 4)
 268                 * (u32 *) b = (__force u32) __cpu_to_be32(*p);
 269
 270         /* Strip trailing whitespace and add newline. */
 271         while (b--, (isspace(*b) || *b == '\0') && b > buf);
 272         strcpy(b + 1, "\n");
 273         ret = b + 2 - buf;
 274  out:
 275         up_read(&fw_device_rwsem);
 276
 277         return ret;
 278 }
 279
 280 #define TEXT_LEAF_ATTR(name, key)                               \
 281         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
 282
 283 static struct config_rom_attribute config_rom_attributes[] = {
 284         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
 285         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
 286         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
 287         IMMEDIATE_ATTR(version, CSR_VERSION),
 288         IMMEDIATE_ATTR(model, CSR_MODEL),
 289         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
 290         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
 291         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
 292 };
 293
 294 static void
 295 init_fw_attribute_group(struct device *dev,
 296                         struct device_attribute *attrs,
 297                         struct fw_attribute_group *group)
 298 {
 299         struct device_attribute *attr;
 300         int i, j;
 301
 302         for (j = 0; attrs[j].attr.name != NULL; j++)
 303                 group->attrs[j] = &attrs[j].attr;
 304
 305         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
 306                 attr = &config_rom_attributes[i].attr;
 307                 if (attr->show(dev, attr, NULL) < 0)
 308                         continue;
 309                 group->attrs[j++] = &attr->attr;
 310         }
 311
 312         BUG_ON(j >= ARRAY_SIZE(group->attrs));
 313         group->attrs[j++] = NULL;
 314         group->groups[0] = &group->group;
 315         group->groups[1] = NULL;
 316         group->group.attrs = group->attrs;
 317         dev->groups = group->groups;
 318 }
 319
 320 static ssize_t
 321 modalias_show(struct device *dev,
 322               struct device_attribute *attr, char *buf)
 323 {
 324         struct fw_unit *unit = fw_unit(dev);
 325         int length;
 326
 327         length = get_modalias(unit, buf, PAGE_SIZE);
 328         strcpy(buf + length, "\n");
 329
 330         return length + 1;
 331 }
 332
 333 static ssize_t
 334 rom_index_show(struct device *dev,
 335                struct device_attribute *attr, char *buf)
 336 {
 337         struct fw_device *device = fw_device(dev->parent);
 338         struct fw_unit *unit = fw_unit(dev);
 339
 340         return snprintf(buf, PAGE_SIZE, "%d\n",
 341                         (int)(unit->directory - device->config_rom));
 342 }
 343
 344 static struct device_attribute fw_unit_attributes[] = {
 345         __ATTR_RO(modalias),
 346         __ATTR_RO(rom_index),
 347         __ATTR_NULL,
 348 };
 349
 350 static ssize_t
 351 config_rom_show(struct device *dev, struct device_attribute *attr, char *buf)
 352 {
 353         struct fw_device *device = fw_device(dev);
 354         size_t length;
 355
 356         down_read(&fw_device_rwsem);
 357         length = device->config_rom_length * 4;
 358         memcpy(buf, device->config_rom, length);
 359         up_read(&fw_device_rwsem);
 360
 361         return length;
 362 }
 363
 364 static ssize_t
 365 guid_show(struct device *dev, struct device_attribute *attr, char *buf)
 366 {
 367         struct fw_device *device = fw_device(dev);
 368         int ret;
 369
 370         down_read(&fw_device_rwsem);
 371         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
 372                        device->config_rom[3], device->config_rom[4]);
 373         up_read(&fw_device_rwsem);
 374
 375         return ret;
 376 }
 377
 378 static struct device_attribute fw_device_attributes[] = {
 379         __ATTR_RO(config_rom),
 380         __ATTR_RO(guid),
 381         __ATTR_NULL,
 382 };
 383
 384 struct read_quadlet_callback_data {
 385         struct completion done;
 386         int rcode;
 387         u32 data;
 388 };
 389
 390 static void
 391 complete_transaction(struct fw_card *card, int rcode,
 392                      void *payload, size_t length, void *data)
 393 {
 394         struct read_quadlet_callback_data *callback_data = data;
 395
 396         if (rcode == RCODE_COMPLETE)
 397                 callback_data->data = be32_to_cpu(*(__be32 *)payload);
 398         callback_data->rcode = rcode;
 399         complete(&callback_data->done);
 400 }
 401
 402 static int
 403 read_rom(struct fw_device *device, int generation, int index, u32 *data)
 404 {
 405         struct read_quadlet_callback_data callback_data;
 406         struct fw_transaction t;
 407         u64 offset;
 408
 409         /* device->node_id, accessed below, must not be older than generation */
 410         smp_rmb();
 411
 412         init_completion(&callback_data.done);
 413
 414         offset = (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4;
 415         fw_send_request(device->card, &t, TCODE_READ_QUADLET_REQUEST,
 416                         device->node_id, generation, device->max_speed,
 417                         offset, NULL, 4, complete_transaction, &callback_data);
 418
 419         wait_for_completion(&callback_data.done);
 420
 421         *data = callback_data.data;
 422
 423         return callback_data.rcode;
 424 }
 425
 426 #define READ_BIB_ROM_SIZE       256
 427 #define READ_BIB_STACK_SIZE     16
 428
 429 /*
 430  * Read the bus info block, perform a speed probe, and read all of the rest of
 431  * the config ROM.  We do all this with a cached bus generation.  If the bus
 432  * generation changes under us, read_bus_info_block will fail and get retried.
 433  * It's better to start all over in this case because the node from which we
 434  * are reading the ROM may have changed the ROM during the reset.
 435  */
 436 static int read_bus_info_block(struct fw_device *device, int generation)
 437 {
 438         u32 *rom, *stack, *old_rom, *new_rom;
 439         u32 sp, key;
 440         int i, end, length, ret = -1;
 441
 442         rom = kmalloc(sizeof(*rom) * READ_BIB_ROM_SIZE +
 443                       sizeof(*stack) * READ_BIB_STACK_SIZE, GFP_KERNEL);
 444         if (rom == NULL)
 445                 return -ENOMEM;
 446
 447         stack = &rom[READ_BIB_ROM_SIZE];
 448
 449         device->max_speed = SCODE_100;
 450
 451         /* First read the bus info block. */
 452         for (i = 0; i < 5; i++) {
 453                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 454                         goto out;
 455                 /*
 456                  * As per IEEE1212 7.2, during power-up, devices can
 457                  * reply with a 0 for the first quadlet of the config
 458                  * rom to indicate that they are booting (for example,
 459                  * if the firmware is on the disk of a external
 460                  * harddisk).  In that case we just fail, and the
 461                  * retry mechanism will try again later.
 462                  */
 463                 if (i == 0 && rom[i] == 0)
 464                         goto out;
 465         }
 466
 467         device->max_speed = device->node->max_speed;
 468
 469         /*
 470          * Determine the speed of
 471          *   - devices with link speed less than PHY speed,
 472          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
 473          *   - all devices if there are 1394b repeaters.
 474          * Note, we cannot use the bus info block's link_spd as starting point
 475          * because some buggy firmwares set it lower than necessary and because
 476          * 1394-1995 nodes do not have the field.
 477          */
 478         if ((rom[2] & 0x7) < device->max_speed ||
 479             device->max_speed == SCODE_BETA ||
 480             device->card->beta_repeaters_present) {
 481                 u32 dummy;
 482
 483                 /* for S1600 and S3200 */
 484                 if (device->max_speed == SCODE_BETA)
 485                         device->max_speed = device->card->link_speed;
 486
 487                 while (device->max_speed > SCODE_100) {
 488                         if (read_rom(device, generation, 0, &dummy) ==
 489                             RCODE_COMPLETE)
 490                                 break;
 491                         device->max_speed--;
 492                 }
 493         }
 494
 495         /*
 496          * Now parse the config rom.  The config rom is a recursive
 497          * directory structure so we parse it using a stack of
 498          * references to the blocks that make up the structure.  We
 499          * push a reference to the root directory on the stack to
 500          * start things off.
 501          */
 502         length = i;
 503         sp = 0;
 504         stack[sp++] = 0xc0000005;
 505         while (sp > 0) {
 506                 /*
 507                  * Pop the next block reference of the stack.  The
 508                  * lower 24 bits is the offset into the config rom,
 509                  * the upper 8 bits are the type of the reference the
 510                  * block.
 511                  */
 512                 key = stack[--sp];
 513                 i = key & 0xffffff;
 514                 if (i >= READ_BIB_ROM_SIZE)
 515                         /*
 516                          * The reference points outside the standard
 517                          * config rom area, something's fishy.
 518                          */
 519                         goto out;
 520
 521                 /* Read header quadlet for the block to get the length. */
 522                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 523                         goto out;
 524                 end = i + (rom[i] >> 16) + 1;
 525                 i++;
 526                 if (end > READ_BIB_ROM_SIZE)
 527                         /*
 528                          * This block extends outside standard config
 529                          * area (and the array we're reading it
 530                          * into).  That's broken, so ignore this
 531                          * device.
 532                          */
 533                         goto out;
 534
 535                 /*
 536                  * Now read in the block.  If this is a directory
 537                  * block, check the entries as we read them to see if
 538                  * it references another block, and push it in that case.
 539                  */
 540                 while (i < end) {
 541                         if (read_rom(device, generation, i, &rom[i]) !=
 542                             RCODE_COMPLETE)
 543                                 goto out;
 544                         if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
 545                             sp < READ_BIB_STACK_SIZE)
 546                                 stack[sp++] = i + rom[i];
 547                         i++;
 548                 }
 549                 if (length < i)
 550                         length = i;
 551         }
 552
 553         old_rom = device->config_rom;
 554         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
 555         if (new_rom == NULL)
 556                 goto out;
 557
 558         down_write(&fw_device_rwsem);
 559         device->config_rom = new_rom;
 560         device->config_rom_length = length;
 561         up_write(&fw_device_rwsem);
 562
 563         kfree(old_rom);
 564         ret = 0;
 565         device->cmc = rom[2] & 1 << 30;
 566  out:
 567         kfree(rom);
 568
 569         return ret;
 570 }
 571
 572 static void fw_unit_release(struct device *dev)
 573 {
 574         struct fw_unit *unit = fw_unit(dev);
 575
 576         kfree(unit);
 577 }
 578
 579 static struct device_type fw_unit_type = {
 580         .uevent         = fw_unit_uevent,
 581         .release        = fw_unit_release,
 582 };
 583
 584 static int is_fw_unit(struct device *dev)
 585 {
 586         return dev->type == &fw_unit_type;
 587 }
 588
 589 static void create_units(struct fw_device *device)
 590 {
 591         struct fw_csr_iterator ci;
 592         struct fw_unit *unit;
 593         int key, value, i;
 594
 595         i = 0;
 596         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 597         while (fw_csr_iterator_next(&ci, &key, &value)) {
 598                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 599                         continue;
 600
 601                 /*
 602                  * Get the address of the unit directory and try to
 603                  * match the drivers id_tables against it.
 604                  */
 605                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 606                 if (unit == NULL) {
 607                         fw_error("failed to allocate memory for unit\n");
 608                         continue;
 609                 }
 610
 611                 unit->directory = ci.p + value - 1;
 612                 unit->device.bus = &fw_bus_type;
 613                 unit->device.type = &fw_unit_type;
 614                 unit->device.parent = &device->device;
 615                 snprintf(unit->device.bus_id, sizeof(unit->device.bus_id),
 616                          "%s.%d", device->device.bus_id, i++);
 617
 618                 init_fw_attribute_group(&unit->device,
 619                                         fw_unit_attributes,
 620                                         &unit->attribute_group);
 621                 if (device_register(&unit->device) < 0)
 622                         goto skip_unit;
 623
 624                 continue;
 625
 626         skip_unit:
 627                 kfree(unit);
 628         }
 629 }
 630
 631 static int shutdown_unit(struct device *device, void *data)
 632 {
 633         device_unregister(device);
 634
 635         return 0;
 636 }
 637
 638 /*
 639  * fw_device_rwsem acts as dual purpose mutex:
 640  *   - serializes accesses to fw_device_idr,
 641  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 642  *     fw_unit.directory, unless those accesses happen at safe occasions
 643  */
 644 DECLARE_RWSEM(fw_device_rwsem);
 645
 646 static DEFINE_IDR(fw_device_idr);
 647 int fw_cdev_major;
 648
 649 struct fw_device *fw_device_get_by_devt(dev_t devt)
 650 {
 651         struct fw_device *device;
 652
 653         down_read(&fw_device_rwsem);
 654         device = idr_find(&fw_device_idr, MINOR(devt));
 655         if (device)
 656                 fw_device_get(device);
 657         up_read(&fw_device_rwsem);
 658
 659         return device;
 660 }
 661
 662 static void fw_device_shutdown(struct work_struct *work)
 663 {
 664         struct fw_device *device =
 665                 container_of(work, struct fw_device, work.work);
 666         int minor = MINOR(device->device.devt);
 667
 668         fw_device_cdev_remove(device);
 669         device_for_each_child(&device->device, NULL, shutdown_unit);
 670         device_unregister(&device->device);
 671
 672         down_write(&fw_device_rwsem);
 673         idr_remove(&fw_device_idr, minor);
 674         up_write(&fw_device_rwsem);
 675         fw_device_put(device);
 676 }
 677
 678 static struct device_type fw_device_type = {
 679         .release        = fw_device_release,
 680 };
 681
 682 /*
 683  * These defines control the retry behavior for reading the config
 684  * rom.  It shouldn't be necessary to tweak these; if the device
 685  * doesn't respond to a config rom read within 10 seconds, it's not
 686  * going to respond at all.  As for the initial delay, a lot of
 687  * devices will be able to respond within half a second after bus
 688  * reset.  On the other hand, it's not really worth being more
 689  * aggressive than that, since it scales pretty well; if 10 devices
 690  * are plugged in, they're all getting read within one second.
 691  */
 692
 693 #define MAX_RETRIES     10
 694 #define RETRY_DELAY     (3 * HZ)
 695 #define INITIAL_DELAY   (HZ / 2)
 696
 697 static void fw_device_init(struct work_struct *work)
 698 {
 699         struct fw_device *device =
 700                 container_of(work, struct fw_device, work.work);
 701         int minor, err;
 702
 703         /*
 704          * All failure paths here set node->data to NULL, so that we
 705          * don't try to do device_for_each_child() on a kfree()'d
 706          * device.
 707          */
 708
 709         if (read_bus_info_block(device, device->generation) < 0) {
 710                 if (device->config_rom_retries < MAX_RETRIES &&
 711                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 712                         device->config_rom_retries++;
 713                         schedule_delayed_work(&device->work, RETRY_DELAY);
 714                 } else {
 715                         fw_notify("giving up on config rom for node id %x\n",
 716                                   device->node_id);
 717                         if (device->node == device->card->root_node)
 718                                 schedule_delayed_work(&device->card->work, 0);
 719                         fw_device_release(&device->device);
 720                 }
 721                 return;
 722         }
 723
 724         err = -ENOMEM;
 725
 726         fw_device_get(device);
 727         down_write(&fw_device_rwsem);
 728         if (idr_pre_get(&fw_device_idr, GFP_KERNEL))
 729                 err = idr_get_new(&fw_device_idr, device, &minor);
 730         up_write(&fw_device_rwsem);
 731
 732         if (err < 0)
 733                 goto error;
 734
 735         device->device.bus = &fw_bus_type;
 736         device->device.type = &fw_device_type;
 737         device->device.parent = device->card->device;
 738         device->device.devt = MKDEV(fw_cdev_major, minor);
 739         snprintf(device->device.bus_id, sizeof(device->device.bus_id),
 740                  "fw%d", minor);
 741
 742         init_fw_attribute_group(&device->device,
 743                                 fw_device_attributes,
 744                                 &device->attribute_group);
 745         if (device_add(&device->device)) {
 746                 fw_error("Failed to add device.\n");
 747                 goto error_with_cdev;
 748         }
 749
 750         create_units(device);
 751
 752         /*
 753          * Transition the device to running state.  If it got pulled
 754          * out from under us while we did the intialization work, we
 755          * have to shut down the device again here.  Normally, though,
 756          * fw_node_event will be responsible for shutting it down when
 757          * necessary.  We have to use the atomic cmpxchg here to avoid
 758          * racing with the FW_NODE_DESTROYED case in
 759          * fw_node_event().
 760          */
 761         if (atomic_cmpxchg(&device->state,
 762                     FW_DEVICE_INITIALIZING,
 763                     FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN) {
 764                 fw_device_shutdown(work);
 765         } else {
 766                 if (device->config_rom_retries)
 767                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
 768                                   "%d config ROM retries\n",
 769                                   device->device.bus_id,
 770                                   device->config_rom[3], device->config_rom[4],
 771                                   1 << device->max_speed,
 772                                   device->config_rom_retries);
 773                 else
 774                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
 775                                   device->device.bus_id,
 776                                   device->config_rom[3], device->config_rom[4],
 777                                   1 << device->max_speed);
 778                 device->config_rom_retries = 0;
 779         }
 780
 781         /*
 782          * Reschedule the IRM work if we just finished reading the
 783          * root node config rom.  If this races with a bus reset we
 784          * just end up running the IRM work a couple of extra times -
 785          * pretty harmless.
 786          */
 787         if (device->node == device->card->root_node)
 788                 schedule_delayed_work(&device->card->work, 0);
 789
 790         return;
 791
 792  error_with_cdev:
 793         down_write(&fw_device_rwsem);
 794         idr_remove(&fw_device_idr, minor);
 795         up_write(&fw_device_rwsem);
 796  error:
 797         fw_device_put(device);          /* fw_device_idr's reference */
 798
 799         put_device(&device->device);    /* our reference */
 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                 down(&dev->sem);
 809                 driver->update(unit);
 810                 up(&dev->sem);
 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 enum {
 826         REREAD_BIB_ERROR,
 827         REREAD_BIB_GONE,
 828         REREAD_BIB_UNCHANGED,
 829         REREAD_BIB_CHANGED,
 830 };
 831
 832 /* Reread and compare bus info block and header of root directory */
 833 static int reread_bus_info_block(struct fw_device *device, int generation)
 834 {
 835         u32 q;
 836         int i;
 837
 838         for (i = 0; i < 6; i++) {
 839                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
 840                         return REREAD_BIB_ERROR;
 841
 842                 if (i == 0 && q == 0)
 843                         return REREAD_BIB_GONE;
 844
 845                 if (i > device->config_rom_length || q != device->config_rom[i])
 846                         return REREAD_BIB_CHANGED;
 847         }
 848
 849         return REREAD_BIB_UNCHANGED;
 850 }
 851
 852 static void fw_device_refresh(struct work_struct *work)
 853 {
 854         struct fw_device *device =
 855                 container_of(work, struct fw_device, work.work);
 856         struct fw_card *card = device->card;
 857         int node_id = device->node_id;
 858
 859         switch (reread_bus_info_block(device, device->generation)) {
 860         case REREAD_BIB_ERROR:
 861                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
 862                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 863                         device->config_rom_retries++;
 864                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
 865
 866                         return;
 867                 }
 868                 goto give_up;
 869
 870         case REREAD_BIB_GONE:
 871                 goto gone;
 872
 873         case REREAD_BIB_UNCHANGED:
 874                 if (atomic_cmpxchg(&device->state,
 875                             FW_DEVICE_INITIALIZING,
 876                             FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
 877                         goto gone;
 878
 879                 fw_device_update(work);
 880                 device->config_rom_retries = 0;
 881                 goto out;
 882
 883         case REREAD_BIB_CHANGED:
 884                 break;
 885         }
 886
 887         /*
 888          * Something changed.  We keep things simple and don't investigate
 889          * further.  We just destroy all previous units and create new ones.
 890          */
 891         device_for_each_child(&device->device, NULL, shutdown_unit);
 892
 893         if (read_bus_info_block(device, device->generation) < 0) {
 894                 if (device->config_rom_retries < MAX_RETRIES &&
 895                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 896                         device->config_rom_retries++;
 897                         schedule_delayed_work(&device->work, RETRY_DELAY);
 898
 899                         return;
 900                 }
 901                 goto give_up;
 902         }
 903
 904         create_units(device);
 905
 906         if (atomic_cmpxchg(&device->state,
 907                     FW_DEVICE_INITIALIZING,
 908                     FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
 909                 goto gone;
 910
 911         fw_notify("refreshed device %s\n", device->device.bus_id);
 912         device->config_rom_retries = 0;
 913         goto out;
 914
 915  give_up:
 916         fw_notify("giving up on refresh of device %s\n", device->device.bus_id);
 917  gone:
 918         atomic_set(&device->state, FW_DEVICE_SHUTDOWN);
 919         fw_device_shutdown(work);
 920  out:
 921         if (node_id == card->root_node->node_id)
 922                 schedule_delayed_work(&card->work, 0);
 923 }
 924
 925 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
 926 {
 927         struct fw_device *device;
 928
 929         switch (event) {
 930         case FW_NODE_CREATED:
 931         case FW_NODE_LINK_ON:
 932                 if (!node->link_on)
 933                         break;
 934  create:
 935                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
 936                 if (device == NULL)
 937                         break;
 938
 939                 /*
 940                  * Do minimal intialization of the device here, the
 941                  * rest will happen in fw_device_init().  We need the
 942                  * card and node so we can read the config rom and we
 943                  * need to do device_initialize() now so
 944                  * device_for_each_child() in FW_NODE_UPDATED is
 945                  * doesn't freak out.
 946                  */
 947                 device_initialize(&device->device);
 948                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
 949                 atomic_inc(&card->device_count);
 950                 device->card = card;
 951                 device->node = fw_node_get(node);
 952                 device->node_id = node->node_id;
 953                 device->generation = card->generation;
 954                 INIT_LIST_HEAD(&device->client_list);
 955
 956                 /*
 957                  * Set the node data to point back to this device so
 958                  * FW_NODE_UPDATED callbacks can update the node_id
 959                  * and generation for the device.
 960                  */
 961                 node->data = device;
 962
 963                 /*
 964                  * Many devices are slow to respond after bus resets,
 965                  * especially if they are bus powered and go through
 966                  * power-up after getting plugged in.  We schedule the
 967                  * first config rom scan half a second after bus reset.
 968                  */
 969                 INIT_DELAYED_WORK(&device->work, fw_device_init);
 970                 schedule_delayed_work(&device->work, INITIAL_DELAY);
 971                 break;
 972
 973         case FW_NODE_INITIATED_RESET:
 974                 device = node->data;
 975                 if (device == NULL)
 976                         goto create;
 977
 978                 device->node_id = node->node_id;
 979                 smp_wmb();  /* update node_id before generation */
 980                 device->generation = card->generation;
 981                 if (atomic_cmpxchg(&device->state,
 982                             FW_DEVICE_RUNNING,
 983                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
 984                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
 985                         schedule_delayed_work(&device->work,
 986                                 node == card->local_node ? 0 : INITIAL_DELAY);
 987                 }
 988                 break;
 989
 990         case FW_NODE_UPDATED:
 991                 if (!node->link_on || node->data == NULL)
 992                         break;
 993
 994                 device = node->data;
 995                 device->node_id = node->node_id;
 996                 smp_wmb();  /* update node_id before generation */
 997                 device->generation = card->generation;
 998                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
 999                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1000                         schedule_delayed_work(&device->work, 0);
1001                 }
1002                 break;
1003
1004         case FW_NODE_DESTROYED:
1005         case FW_NODE_LINK_OFF:
1006                 if (!node->data)
1007                         break;
1008
1009                 /*
1010                  * Destroy the device associated with the node.  There
1011                  * are two cases here: either the device is fully
1012                  * initialized (FW_DEVICE_RUNNING) or we're in the
1013                  * process of reading its config rom
1014                  * (FW_DEVICE_INITIALIZING).  If it is fully
1015                  * initialized we can reuse device->work to schedule a
1016                  * full fw_device_shutdown().  If not, there's work
1017                  * scheduled to read it's config rom, and we just put
1018                  * the device in shutdown state to have that code fail
1019                  * to create the device.
1020                  */
1021                 device = node->data;
1022                 if (atomic_xchg(&device->state,
1023                                 FW_DEVICE_SHUTDOWN) == FW_DEVICE_RUNNING) {
1024                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1025                         schedule_delayed_work(&device->work, 0);
1026                 }
1027                 break;
1028         }
1029 }