SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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/jiffies.h>
  29 #include <linux/string.h>
  30 #include <linux/rwsem.h>
  31 #include <linux/semaphore.h>
  32 #include <linux/spinlock.h>
  33 #include <asm/system.h>
  34 #include <linux/ctype.h>
  35 #include "fw-transaction.h"
  36 #include "fw-topology.h"
  37 #include "fw-device.h"
  38
  39 void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
  40 {
  41         ci->p = p + 1;
  42         ci->end = ci->p + (p[0] >> 16);
  43 }
  44 EXPORT_SYMBOL(fw_csr_iterator_init);
  45
  46 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
  47 {
  48         *key = *ci->p >> 24;
  49         *value = *ci->p & 0xffffff;
  50
  51         return ci->p++ < ci->end;
  52 }
  53 EXPORT_SYMBOL(fw_csr_iterator_next);
  54
  55 static int is_fw_unit(struct device *dev);
  56
  57 static int match_unit_directory(u32 * directory, const struct fw_device_id *id)
  58 {
  59         struct fw_csr_iterator ci;
  60         int key, value, match;
  61
  62         match = 0;
  63         fw_csr_iterator_init(&ci, directory);
  64         while (fw_csr_iterator_next(&ci, &key, &value)) {
  65                 if (key == CSR_VENDOR && value == id->vendor)
  66                         match |= FW_MATCH_VENDOR;
  67                 if (key == CSR_MODEL && value == id->model)
  68                         match |= FW_MATCH_MODEL;
  69                 if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
  70                         match |= FW_MATCH_SPECIFIER_ID;
  71                 if (key == CSR_VERSION && value == id->version)
  72                         match |= FW_MATCH_VERSION;
  73         }
  74
  75         return (match & id->match_flags) == id->match_flags;
  76 }
  77
  78 static int fw_unit_match(struct device *dev, struct device_driver *drv)
  79 {
  80         struct fw_unit *unit = fw_unit(dev);
  81         struct fw_driver *driver = fw_driver(drv);
  82         int i;
  83
  84         /* We only allow binding to fw_units. */
  85         if (!is_fw_unit(dev))
  86                 return 0;
  87
  88         for (i = 0; driver->id_table[i].match_flags != 0; i++) {
  89                 if (match_unit_directory(unit->directory, &driver->id_table[i]))
  90                         return 1;
  91         }
  92
  93         return 0;
  94 }
  95
  96 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
  97 {
  98         struct fw_device *device = fw_device(unit->device.parent);
  99         struct fw_csr_iterator ci;
 100
 101         int key, value;
 102         int vendor = 0;
 103         int model = 0;
 104         int specifier_id = 0;
 105         int version = 0;
 106
 107         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 108         while (fw_csr_iterator_next(&ci, &key, &value)) {
 109                 switch (key) {
 110                 case CSR_VENDOR:
 111                         vendor = value;
 112                         break;
 113                 case CSR_MODEL:
 114                         model = value;
 115                         break;
 116                 }
 117         }
 118
 119         fw_csr_iterator_init(&ci, unit->directory);
 120         while (fw_csr_iterator_next(&ci, &key, &value)) {
 121                 switch (key) {
 122                 case CSR_SPECIFIER_ID:
 123                         specifier_id = value;
 124                         break;
 125                 case CSR_VERSION:
 126                         version = value;
 127                         break;
 128                 }
 129         }
 130
 131         return snprintf(buffer, buffer_size,
 132                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
 133                         vendor, model, specifier_id, version);
 134 }
 135
 136 static int
 137 fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 138 {
 139         struct fw_unit *unit = fw_unit(dev);
 140         char modalias[64];
 141
 142         get_modalias(unit, modalias, sizeof(modalias));
 143
 144         if (add_uevent_var(env, "MODALIAS=%s", modalias))
 145                 return -ENOMEM;
 146
 147         return 0;
 148 }
 149
 150 struct bus_type fw_bus_type = {
 151         .name = "firewire",
 152         .match = fw_unit_match,
 153 };
 154 EXPORT_SYMBOL(fw_bus_type);
 155
 156 static void fw_device_release(struct device *dev)
 157 {
 158         struct fw_device *device = fw_device(dev);
 159         struct fw_card *card = device->card;
 160         unsigned long flags;
 161
 162         /*
 163          * Take the card lock so we don't set this to NULL while a
 164          * FW_NODE_UPDATED callback is being handled or while the
 165          * bus manager work looks at this node.
 166          */
 167         spin_lock_irqsave(&card->lock, flags);
 168         device->node->data = NULL;
 169         spin_unlock_irqrestore(&card->lock, flags);
 170
 171         fw_node_put(device->node);
 172         kfree(device->config_rom);
 173         kfree(device);
 174         fw_card_put(card);
 175 }
 176
 177 int fw_device_enable_phys_dma(struct fw_device *device)
 178 {
 179         int generation = device->generation;
 180
 181         /* device->node_id, accessed below, must not be older than generation */
 182         smp_rmb();
 183
 184         return device->card->driver->enable_phys_dma(device->card,
 185                                                      device->node_id,
 186                                                      generation);
 187 }
 188 EXPORT_SYMBOL(fw_device_enable_phys_dma);
 189
 190 struct config_rom_attribute {
 191         struct device_attribute attr;
 192         u32 key;
 193 };
 194
 195 static ssize_t
 196 show_immediate(struct device *dev, struct device_attribute *dattr, char *buf)
 197 {
 198         struct config_rom_attribute *attr =
 199                 container_of(dattr, struct config_rom_attribute, attr);
 200         struct fw_csr_iterator ci;
 201         u32 *dir;
 202         int key, value, ret = -ENOENT;
 203
 204         down_read(&fw_device_rwsem);
 205
 206         if (is_fw_unit(dev))
 207                 dir = fw_unit(dev)->directory;
 208         else
 209                 dir = fw_device(dev)->config_rom + 5;
 210
 211         fw_csr_iterator_init(&ci, dir);
 212         while (fw_csr_iterator_next(&ci, &key, &value))
 213                 if (attr->key == key) {
 214                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
 215                                        "0x%06x\n", value);
 216                         break;
 217                 }
 218
 219         up_read(&fw_device_rwsem);
 220
 221         return ret;
 222 }
 223
 224 #define IMMEDIATE_ATTR(name, key)                               \
 225         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
 226
 227 static ssize_t
 228 show_text_leaf(struct device *dev, struct device_attribute *dattr, char *buf)
 229 {
 230         struct config_rom_attribute *attr =
 231                 container_of(dattr, struct config_rom_attribute, attr);
 232         struct fw_csr_iterator ci;
 233         u32 *dir, *block = NULL, *p, *end;
 234         int length, key, value, last_key = 0, ret = -ENOENT;
 235         char *b;
 236
 237         down_read(&fw_device_rwsem);
 238
 239         if (is_fw_unit(dev))
 240                 dir = fw_unit(dev)->directory;
 241         else
 242                 dir = fw_device(dev)->config_rom + 5;
 243
 244         fw_csr_iterator_init(&ci, dir);
 245         while (fw_csr_iterator_next(&ci, &key, &value)) {
 246                 if (attr->key == last_key &&
 247                     key == (CSR_DESCRIPTOR | CSR_LEAF))
 248                         block = ci.p - 1 + value;
 249                 last_key = key;
 250         }
 251
 252         if (block == NULL)
 253                 goto out;
 254
 255         length = min(block[0] >> 16, 256U);
 256         if (length < 3)
 257                 goto out;
 258
 259         if (block[1] != 0 || block[2] != 0)
 260                 /* Unknown encoding. */
 261                 goto out;
 262
 263         if (buf == NULL) {
 264                 ret = length * 4;
 265                 goto out;
 266         }
 267
 268         b = buf;
 269         end = &block[length + 1];
 270         for (p = &block[3]; p < end; p++, b += 4)
 271                 * (u32 *) b = (__force u32) __cpu_to_be32(*p);
 272
 273         /* Strip trailing whitespace and add newline. */
 274         while (b--, (isspace(*b) || *b == '\0') && b > buf);
 275         strcpy(b + 1, "\n");
 276         ret = b + 2 - buf;
 277  out:
 278         up_read(&fw_device_rwsem);
 279
 280         return ret;
 281 }
 282
 283 #define TEXT_LEAF_ATTR(name, key)                               \
 284         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
 285
 286 static struct config_rom_attribute config_rom_attributes[] = {
 287         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
 288         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
 289         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
 290         IMMEDIATE_ATTR(version, CSR_VERSION),
 291         IMMEDIATE_ATTR(model, CSR_MODEL),
 292         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
 293         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
 294         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
 295 };
 296
 297 static void
 298 init_fw_attribute_group(struct device *dev,
 299                         struct device_attribute *attrs,
 300                         struct fw_attribute_group *group)
 301 {
 302         struct device_attribute *attr;
 303         int i, j;
 304
 305         for (j = 0; attrs[j].attr.name != NULL; j++)
 306                 group->attrs[j] = &attrs[j].attr;
 307
 308         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
 309                 attr = &config_rom_attributes[i].attr;
 310                 if (attr->show(dev, attr, NULL) < 0)
 311                         continue;
 312                 group->attrs[j++] = &attr->attr;
 313         }
 314
 315         BUG_ON(j >= ARRAY_SIZE(group->attrs));
 316         group->attrs[j++] = NULL;
 317         group->groups[0] = &group->group;
 318         group->groups[1] = NULL;
 319         group->group.attrs = group->attrs;
 320         dev->groups = group->groups;
 321 }
 322
 323 static ssize_t
 324 modalias_show(struct device *dev,
 325               struct device_attribute *attr, char *buf)
 326 {
 327         struct fw_unit *unit = fw_unit(dev);
 328         int length;
 329
 330         length = get_modalias(unit, buf, PAGE_SIZE);
 331         strcpy(buf + length, "\n");
 332
 333         return length + 1;
 334 }
 335
 336 static ssize_t
 337 rom_index_show(struct device *dev,
 338                struct device_attribute *attr, char *buf)
 339 {
 340         struct fw_device *device = fw_device(dev->parent);
 341         struct fw_unit *unit = fw_unit(dev);
 342
 343         return snprintf(buf, PAGE_SIZE, "%d\n",
 344                         (int)(unit->directory - device->config_rom));
 345 }
 346
 347 static struct device_attribute fw_unit_attributes[] = {
 348         __ATTR_RO(modalias),
 349         __ATTR_RO(rom_index),
 350         __ATTR_NULL,
 351 };
 352
 353 static ssize_t
 354 config_rom_show(struct device *dev, struct device_attribute *attr, char *buf)
 355 {
 356         struct fw_device *device = fw_device(dev);
 357         size_t length;
 358
 359         down_read(&fw_device_rwsem);
 360         length = device->config_rom_length * 4;
 361         memcpy(buf, device->config_rom, length);
 362         up_read(&fw_device_rwsem);
 363
 364         return length;
 365 }
 366
 367 static ssize_t
 368 guid_show(struct device *dev, struct device_attribute *attr, char *buf)
 369 {
 370         struct fw_device *device = fw_device(dev);
 371         int ret;
 372
 373         down_read(&fw_device_rwsem);
 374         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
 375                        device->config_rom[3], device->config_rom[4]);
 376         up_read(&fw_device_rwsem);
 377
 378         return ret;
 379 }
 380
 381 static struct device_attribute fw_device_attributes[] = {
 382         __ATTR_RO(config_rom),
 383         __ATTR_RO(guid),
 384         __ATTR_NULL,
 385 };
 386
 387 static int
 388 read_rom(struct fw_device *device, int generation, int index, u32 *data)
 389 {
 390         int rcode;
 391
 392         /* device->node_id, accessed below, must not be older than generation */
 393         smp_rmb();
 394
 395         rcode = fw_run_transaction(device->card, TCODE_READ_QUADLET_REQUEST,
 396                         device->node_id, generation, device->max_speed,
 397                         (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4,
 398                         data, 4);
 399         be32_to_cpus(data);
 400
 401         return rcode;
 402 }
 403
 404 #define READ_BIB_ROM_SIZE       256
 405 #define READ_BIB_STACK_SIZE     16
 406
 407 /*
 408  * Read the bus info block, perform a speed probe, and read all of the rest of
 409  * the config ROM.  We do all this with a cached bus generation.  If the bus
 410  * generation changes under us, read_bus_info_block will fail and get retried.
 411  * It's better to start all over in this case because the node from which we
 412  * are reading the ROM may have changed the ROM during the reset.
 413  */
 414 static int read_bus_info_block(struct fw_device *device, int generation)
 415 {
 416         u32 *rom, *stack, *old_rom, *new_rom;
 417         u32 sp, key;
 418         int i, end, length, ret = -1;
 419
 420         rom = kmalloc(sizeof(*rom) * READ_BIB_ROM_SIZE +
 421                       sizeof(*stack) * READ_BIB_STACK_SIZE, GFP_KERNEL);
 422         if (rom == NULL)
 423                 return -ENOMEM;
 424
 425         stack = &rom[READ_BIB_ROM_SIZE];
 426
 427         device->max_speed = SCODE_100;
 428
 429         /* First read the bus info block. */
 430         for (i = 0; i < 5; i++) {
 431                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 432                         goto out;
 433                 /*
 434                  * As per IEEE1212 7.2, during power-up, devices can
 435                  * reply with a 0 for the first quadlet of the config
 436                  * rom to indicate that they are booting (for example,
 437                  * if the firmware is on the disk of a external
 438                  * harddisk).  In that case we just fail, and the
 439                  * retry mechanism will try again later.
 440                  */
 441                 if (i == 0 && rom[i] == 0)
 442                         goto out;
 443         }
 444
 445         device->max_speed = device->node->max_speed;
 446
 447         /*
 448          * Determine the speed of
 449          *   - devices with link speed less than PHY speed,
 450          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
 451          *   - all devices if there are 1394b repeaters.
 452          * Note, we cannot use the bus info block's link_spd as starting point
 453          * because some buggy firmwares set it lower than necessary and because
 454          * 1394-1995 nodes do not have the field.
 455          */
 456         if ((rom[2] & 0x7) < device->max_speed ||
 457             device->max_speed == SCODE_BETA ||
 458             device->card->beta_repeaters_present) {
 459                 u32 dummy;
 460
 461                 /* for S1600 and S3200 */
 462                 if (device->max_speed == SCODE_BETA)
 463                         device->max_speed = device->card->link_speed;
 464
 465                 while (device->max_speed > SCODE_100) {
 466                         if (read_rom(device, generation, 0, &dummy) ==
 467                             RCODE_COMPLETE)
 468                                 break;
 469                         device->max_speed--;
 470                 }
 471         }
 472
 473         /*
 474          * Now parse the config rom.  The config rom is a recursive
 475          * directory structure so we parse it using a stack of
 476          * references to the blocks that make up the structure.  We
 477          * push a reference to the root directory on the stack to
 478          * start things off.
 479          */
 480         length = i;
 481         sp = 0;
 482         stack[sp++] = 0xc0000005;
 483         while (sp > 0) {
 484                 /*
 485                  * Pop the next block reference of the stack.  The
 486                  * lower 24 bits is the offset into the config rom,
 487                  * the upper 8 bits are the type of the reference the
 488                  * block.
 489                  */
 490                 key = stack[--sp];
 491                 i = key & 0xffffff;
 492                 if (i >= READ_BIB_ROM_SIZE)
 493                         /*
 494                          * The reference points outside the standard
 495                          * config rom area, something's fishy.
 496                          */
 497                         goto out;
 498
 499                 /* Read header quadlet for the block to get the length. */
 500                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 501                         goto out;
 502                 end = i + (rom[i] >> 16) + 1;
 503                 i++;
 504                 if (end > READ_BIB_ROM_SIZE)
 505                         /*
 506                          * This block extends outside standard config
 507                          * area (and the array we're reading it
 508                          * into).  That's broken, so ignore this
 509                          * device.
 510                          */
 511                         goto out;
 512
 513                 /*
 514                  * Now read in the block.  If this is a directory
 515                  * block, check the entries as we read them to see if
 516                  * it references another block, and push it in that case.
 517                  */
 518                 while (i < end) {
 519                         if (read_rom(device, generation, i, &rom[i]) !=
 520                             RCODE_COMPLETE)
 521                                 goto out;
 522                         if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
 523                             sp < READ_BIB_STACK_SIZE)
 524                                 stack[sp++] = i + rom[i];
 525                         i++;
 526                 }
 527                 if (length < i)
 528                         length = i;
 529         }
 530
 531         old_rom = device->config_rom;
 532         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
 533         if (new_rom == NULL)
 534                 goto out;
 535
 536         down_write(&fw_device_rwsem);
 537         device->config_rom = new_rom;
 538         device->config_rom_length = length;
 539         up_write(&fw_device_rwsem);
 540
 541         kfree(old_rom);
 542         ret = 0;
 543         device->cmc = rom[2] & 1 << 30;
 544  out:
 545         kfree(rom);
 546
 547         return ret;
 548 }
 549
 550 static void fw_unit_release(struct device *dev)
 551 {
 552         struct fw_unit *unit = fw_unit(dev);
 553
 554         kfree(unit);
 555 }
 556
 557 static struct device_type fw_unit_type = {
 558         .uevent         = fw_unit_uevent,
 559         .release        = fw_unit_release,
 560 };
 561
 562 static int is_fw_unit(struct device *dev)
 563 {
 564         return dev->type == &fw_unit_type;
 565 }
 566
 567 static void create_units(struct fw_device *device)
 568 {
 569         struct fw_csr_iterator ci;
 570         struct fw_unit *unit;
 571         int key, value, i;
 572
 573         i = 0;
 574         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 575         while (fw_csr_iterator_next(&ci, &key, &value)) {
 576                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 577                         continue;
 578
 579                 /*
 580                  * Get the address of the unit directory and try to
 581                  * match the drivers id_tables against it.
 582                  */
 583                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 584                 if (unit == NULL) {
 585                         fw_error("failed to allocate memory for unit\n");
 586                         continue;
 587                 }
 588
 589                 unit->directory = ci.p + value - 1;
 590                 unit->device.bus = &fw_bus_type;
 591                 unit->device.type = &fw_unit_type;
 592                 unit->device.parent = &device->device;
 593                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
 594
 595                 init_fw_attribute_group(&unit->device,
 596                                         fw_unit_attributes,
 597                                         &unit->attribute_group);
 598                 if (device_register(&unit->device) < 0)
 599                         goto skip_unit;
 600
 601                 continue;
 602
 603         skip_unit:
 604                 kfree(unit);
 605         }
 606 }
 607
 608 static int shutdown_unit(struct device *device, void *data)
 609 {
 610         device_unregister(device);
 611
 612         return 0;
 613 }
 614
 615 /*
 616  * fw_device_rwsem acts as dual purpose mutex:
 617  *   - serializes accesses to fw_device_idr,
 618  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 619  *     fw_unit.directory, unless those accesses happen at safe occasions
 620  */
 621 DECLARE_RWSEM(fw_device_rwsem);
 622
 623 DEFINE_IDR(fw_device_idr);
 624 int fw_cdev_major;
 625
 626 struct fw_device *fw_device_get_by_devt(dev_t devt)
 627 {
 628         struct fw_device *device;
 629
 630         down_read(&fw_device_rwsem);
 631         device = idr_find(&fw_device_idr, MINOR(devt));
 632         if (device)
 633                 fw_device_get(device);
 634         up_read(&fw_device_rwsem);
 635
 636         return device;
 637 }
 638
 639 /*
 640  * These defines control the retry behavior for reading the config
 641  * rom.  It shouldn't be necessary to tweak these; if the device
 642  * doesn't respond to a config rom read within 10 seconds, it's not
 643  * going to respond at all.  As for the initial delay, a lot of
 644  * devices will be able to respond within half a second after bus
 645  * reset.  On the other hand, it's not really worth being more
 646  * aggressive than that, since it scales pretty well; if 10 devices
 647  * are plugged in, they're all getting read within one second.
 648  */
 649
 650 #define MAX_RETRIES     10
 651 #define RETRY_DELAY     (3 * HZ)
 652 #define INITIAL_DELAY   (HZ / 2)
 653 #define SHUTDOWN_DELAY  (2 * HZ)
 654
 655 static void fw_device_shutdown(struct work_struct *work)
 656 {
 657         struct fw_device *device =
 658                 container_of(work, struct fw_device, work.work);
 659         int minor = MINOR(device->device.devt);
 660
 661         if (time_is_after_jiffies(device->card->reset_jiffies + SHUTDOWN_DELAY)
 662             && !list_empty(&device->card->link)) {
 663                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 664                 return;
 665         }
 666
 667         if (atomic_cmpxchg(&device->state,
 668                            FW_DEVICE_GONE,
 669                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
 670                 return;
 671
 672         fw_device_cdev_remove(device);
 673         device_for_each_child(&device->device, NULL, shutdown_unit);
 674         device_unregister(&device->device);
 675
 676         down_write(&fw_device_rwsem);
 677         idr_remove(&fw_device_idr, minor);
 678         up_write(&fw_device_rwsem);
 679
 680         fw_device_put(device);
 681 }
 682
 683 static struct device_type fw_device_type = {
 684         .release        = fw_device_release,
 685 };
 686
 687 static void fw_device_update(struct work_struct *work);
 688
 689 /*
 690  * If a device was pending for deletion because its node went away but its
 691  * bus info block and root directory header matches that of a newly discovered
 692  * device, revive the existing fw_device.
 693  * The newly allocated fw_device becomes obsolete instead.
 694  */
 695 static int lookup_existing_device(struct device *dev, void *data)
 696 {
 697         struct fw_device *old = fw_device(dev);
 698         struct fw_device *new = data;
 699         struct fw_card *card = new->card;
 700         int match = 0;
 701
 702         down_read(&fw_device_rwsem); /* serialize config_rom access */
 703         spin_lock_irq(&card->lock);  /* serialize node access */
 704
 705         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
 706             atomic_cmpxchg(&old->state,
 707                            FW_DEVICE_GONE,
 708                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 709                 struct fw_node *current_node = new->node;
 710                 struct fw_node *obsolete_node = old->node;
 711
 712                 new->node = obsolete_node;
 713                 new->node->data = new;
 714                 old->node = current_node;
 715                 old->node->data = old;
 716
 717                 old->max_speed = new->max_speed;
 718                 old->node_id = current_node->node_id;
 719                 smp_wmb();  /* update node_id before generation */
 720                 old->generation = card->generation;
 721                 old->config_rom_retries = 0;
 722                 fw_notify("rediscovered device %s\n", dev_name(dev));
 723
 724                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
 725                 schedule_delayed_work(&old->work, 0);
 726
 727                 if (current_node == card->root_node)
 728                         fw_schedule_bm_work(card, 0);
 729
 730                 match = 1;
 731         }
 732
 733         spin_unlock_irq(&card->lock);
 734         up_read(&fw_device_rwsem);
 735
 736         return match;
 737 }
 738
 739 static void fw_device_init(struct work_struct *work)
 740 {
 741         struct fw_device *device =
 742                 container_of(work, struct fw_device, work.work);
 743         struct device *revived_dev;
 744         int minor, err;
 745
 746         /*
 747          * All failure paths here set node->data to NULL, so that we
 748          * don't try to do device_for_each_child() on a kfree()'d
 749          * device.
 750          */
 751
 752         if (read_bus_info_block(device, device->generation) < 0) {
 753                 if (device->config_rom_retries < MAX_RETRIES &&
 754                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 755                         device->config_rom_retries++;
 756                         schedule_delayed_work(&device->work, RETRY_DELAY);
 757                 } else {
 758                         fw_notify("giving up on config rom for node id %x\n",
 759                                   device->node_id);
 760                         if (device->node == device->card->root_node)
 761                                 fw_schedule_bm_work(device->card, 0);
 762                         fw_device_release(&device->device);
 763                 }
 764                 return;
 765         }
 766
 767         revived_dev = device_find_child(device->card->device,
 768                                         device, lookup_existing_device);
 769         if (revived_dev) {
 770                 put_device(revived_dev);
 771                 fw_device_release(&device->device);
 772
 773                 return;
 774         }
 775
 776         device_initialize(&device->device);
 777
 778         fw_device_get(device);
 779         down_write(&fw_device_rwsem);
 780         err = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
 781               idr_get_new(&fw_device_idr, device, &minor) :
 782               -ENOMEM;
 783         up_write(&fw_device_rwsem);
 784
 785         if (err < 0)
 786                 goto error;
 787
 788         device->device.bus = &fw_bus_type;
 789         device->device.type = &fw_device_type;
 790         device->device.parent = device->card->device;
 791         device->device.devt = MKDEV(fw_cdev_major, minor);
 792         dev_set_name(&device->device, "fw%d", minor);
 793
 794         init_fw_attribute_group(&device->device,
 795                                 fw_device_attributes,
 796                                 &device->attribute_group);
 797         if (device_add(&device->device)) {
 798                 fw_error("Failed to add device.\n");
 799                 goto error_with_cdev;
 800         }
 801
 802         create_units(device);
 803
 804         /*
 805          * Transition the device to running state.  If it got pulled
 806          * out from under us while we did the intialization work, we
 807          * have to shut down the device again here.  Normally, though,
 808          * fw_node_event will be responsible for shutting it down when
 809          * necessary.  We have to use the atomic cmpxchg here to avoid
 810          * racing with the FW_NODE_DESTROYED case in
 811          * fw_node_event().
 812          */
 813         if (atomic_cmpxchg(&device->state,
 814                            FW_DEVICE_INITIALIZING,
 815                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 816                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
 817                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 818         } else {
 819                 if (device->config_rom_retries)
 820                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
 821                                   "%d config ROM retries\n",
 822                                   dev_name(&device->device),
 823                                   device->config_rom[3], device->config_rom[4],
 824                                   1 << device->max_speed,
 825                                   device->config_rom_retries);
 826                 else
 827                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
 828                                   dev_name(&device->device),
 829                                   device->config_rom[3], device->config_rom[4],
 830                                   1 << device->max_speed);
 831                 device->config_rom_retries = 0;
 832         }
 833
 834         /*
 835          * Reschedule the IRM work if we just finished reading the
 836          * root node config rom.  If this races with a bus reset we
 837          * just end up running the IRM work a couple of extra times -
 838          * pretty harmless.
 839          */
 840         if (device->node == device->card->root_node)
 841                 fw_schedule_bm_work(device->card, 0);
 842
 843         return;
 844
 845  error_with_cdev:
 846         down_write(&fw_device_rwsem);
 847         idr_remove(&fw_device_idr, minor);
 848         up_write(&fw_device_rwsem);
 849  error:
 850         fw_device_put(device);          /* fw_device_idr's reference */
 851
 852         put_device(&device->device);    /* our reference */
 853 }
 854
 855 static int update_unit(struct device *dev, void *data)
 856 {
 857         struct fw_unit *unit = fw_unit(dev);
 858         struct fw_driver *driver = (struct fw_driver *)dev->driver;
 859
 860         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
 861                 down(&dev->sem);
 862                 driver->update(unit);
 863                 up(&dev->sem);
 864         }
 865
 866         return 0;
 867 }
 868
 869 static void fw_device_update(struct work_struct *work)
 870 {
 871         struct fw_device *device =
 872                 container_of(work, struct fw_device, work.work);
 873
 874         fw_device_cdev_update(device);
 875         device_for_each_child(&device->device, NULL, update_unit);
 876 }
 877
 878 enum {
 879         REREAD_BIB_ERROR,
 880         REREAD_BIB_GONE,
 881         REREAD_BIB_UNCHANGED,
 882         REREAD_BIB_CHANGED,
 883 };
 884
 885 /* Reread and compare bus info block and header of root directory */
 886 static int reread_bus_info_block(struct fw_device *device, int generation)
 887 {
 888         u32 q;
 889         int i;
 890
 891         for (i = 0; i < 6; i++) {
 892                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
 893                         return REREAD_BIB_ERROR;
 894
 895                 if (i == 0 && q == 0)
 896                         return REREAD_BIB_GONE;
 897
 898                 if (i > device->config_rom_length || q != device->config_rom[i])
 899                         return REREAD_BIB_CHANGED;
 900         }
 901
 902         return REREAD_BIB_UNCHANGED;
 903 }
 904
 905 static void fw_device_refresh(struct work_struct *work)
 906 {
 907         struct fw_device *device =
 908                 container_of(work, struct fw_device, work.work);
 909         struct fw_card *card = device->card;
 910         int node_id = device->node_id;
 911
 912         switch (reread_bus_info_block(device, device->generation)) {
 913         case REREAD_BIB_ERROR:
 914                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
 915                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 916                         device->config_rom_retries++;
 917                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
 918
 919                         return;
 920                 }
 921                 goto give_up;
 922
 923         case REREAD_BIB_GONE:
 924                 goto gone;
 925
 926         case REREAD_BIB_UNCHANGED:
 927                 if (atomic_cmpxchg(&device->state,
 928                                    FW_DEVICE_INITIALIZING,
 929                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
 930                         goto gone;
 931
 932                 fw_device_update(work);
 933                 device->config_rom_retries = 0;
 934                 goto out;
 935
 936         case REREAD_BIB_CHANGED:
 937                 break;
 938         }
 939
 940         /*
 941          * Something changed.  We keep things simple and don't investigate
 942          * further.  We just destroy all previous units and create new ones.
 943          */
 944         device_for_each_child(&device->device, NULL, shutdown_unit);
 945
 946         if (read_bus_info_block(device, device->generation) < 0) {
 947                 if (device->config_rom_retries < MAX_RETRIES &&
 948                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 949                         device->config_rom_retries++;
 950                         schedule_delayed_work(&device->work, RETRY_DELAY);
 951
 952                         return;
 953                 }
 954                 goto give_up;
 955         }
 956
 957         create_units(device);
 958
 959         if (atomic_cmpxchg(&device->state,
 960                            FW_DEVICE_INITIALIZING,
 961                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
 962                 goto gone;
 963
 964         fw_notify("refreshed device %s\n", dev_name(&device->device));
 965         device->config_rom_retries = 0;
 966         goto out;
 967
 968  give_up:
 969         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
 970  gone:
 971         atomic_set(&device->state, FW_DEVICE_GONE);
 972         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
 973         schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 974  out:
 975         if (node_id == card->root_node->node_id)
 976                 fw_schedule_bm_work(card, 0);
 977 }
 978
 979 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
 980 {
 981         struct fw_device *device;
 982
 983         switch (event) {
 984         case FW_NODE_CREATED:
 985         case FW_NODE_LINK_ON:
 986                 if (!node->link_on)
 987                         break;
 988  create:
 989                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
 990                 if (device == NULL)
 991                         break;
 992
 993                 /*
 994                  * Do minimal intialization of the device here, the
 995                  * rest will happen in fw_device_init().
 996                  *
 997                  * Attention:  A lot of things, even fw_device_get(),
 998                  * cannot be done before fw_device_init() finished!
 999                  * You can basically just check device->state and
1000                  * schedule work until then, but only while holding
1001                  * card->lock.
1002                  */
1003                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1004                 device->card = fw_card_get(card);
1005                 device->node = fw_node_get(node);
1006                 device->node_id = node->node_id;
1007                 device->generation = card->generation;
1008                 spin_lock_init(&device->client_list_lock);
1009                 INIT_LIST_HEAD(&device->client_list);
1010
1011                 /*
1012                  * Set the node data to point back to this device so
1013                  * FW_NODE_UPDATED callbacks can update the node_id
1014                  * and generation for the device.
1015                  */
1016                 node->data = device;
1017
1018                 /*
1019                  * Many devices are slow to respond after bus resets,
1020                  * especially if they are bus powered and go through
1021                  * power-up after getting plugged in.  We schedule the
1022                  * first config rom scan half a second after bus reset.
1023                  */
1024                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1025                 schedule_delayed_work(&device->work, INITIAL_DELAY);
1026                 break;
1027
1028         case FW_NODE_INITIATED_RESET:
1029                 device = node->data;
1030                 if (device == NULL)
1031                         goto create;
1032
1033                 device->node_id = node->node_id;
1034                 smp_wmb();  /* update node_id before generation */
1035                 device->generation = card->generation;
1036                 if (atomic_cmpxchg(&device->state,
1037                             FW_DEVICE_RUNNING,
1038                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1039                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1040                         schedule_delayed_work(&device->work,
1041                                 node == card->local_node ? 0 : INITIAL_DELAY);
1042                 }
1043                 break;
1044
1045         case FW_NODE_UPDATED:
1046                 if (!node->link_on || node->data == NULL)
1047                         break;
1048
1049                 device = node->data;
1050                 device->node_id = node->node_id;
1051                 smp_wmb();  /* update node_id before generation */
1052                 device->generation = card->generation;
1053                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1054                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1055                         schedule_delayed_work(&device->work, 0);
1056                 }
1057                 break;
1058
1059         case FW_NODE_DESTROYED:
1060         case FW_NODE_LINK_OFF:
1061                 if (!node->data)
1062                         break;
1063
1064                 /*
1065                  * Destroy the device associated with the node.  There
1066                  * are two cases here: either the device is fully
1067                  * initialized (FW_DEVICE_RUNNING) or we're in the
1068                  * process of reading its config rom
1069                  * (FW_DEVICE_INITIALIZING).  If it is fully
1070                  * initialized we can reuse device->work to schedule a
1071                  * full fw_device_shutdown().  If not, there's work
1072                  * scheduled to read it's config rom, and we just put
1073                  * the device in shutdown state to have that code fail
1074                  * to create the device.
1075                  */
1076                 device = node->data;
1077                 if (atomic_xchg(&device->state,
1078                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1079                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1080                         schedule_delayed_work(&device->work,
1081                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1082                 }
1083                 break;
1084         }
1085 }