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/ctype.h>
  22 #include <linux/delay.h>
  23 #include <linux/device.h>
  24 #include <linux/errno.h>
  25 #include <linux/idr.h>
  26 #include <linux/jiffies.h>
  27 #include <linux/kobject.h>
  28 #include <linux/list.h>
  29 #include <linux/mutex.h>
  30 #include <linux/rwsem.h>
  31 #include <linux/semaphore.h>
  32 #include <linux/spinlock.h>
  33 #include <linux/string.h>
  34 #include <linux/workqueue.h>
  35
  36 #include <asm/system.h>
  37
  38 #include "fw-device.h"
  39 #include "fw-topology.h"
  40 #include "fw-transaction.h"
  41
  42 void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
  43 {
  44         ci->p = p + 1;
  45         ci->end = ci->p + (p[0] >> 16);
  46 }
  47 EXPORT_SYMBOL(fw_csr_iterator_init);
  48
  49 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
  50 {
  51         *key = *ci->p >> 24;
  52         *value = *ci->p & 0xffffff;
  53
  54         return ci->p++ < ci->end;
  55 }
  56 EXPORT_SYMBOL(fw_csr_iterator_next);
  57
  58 static int is_fw_unit(struct device *dev);
  59
  60 static int match_unit_directory(u32 * directory, const struct fw_device_id *id)
  61 {
  62         struct fw_csr_iterator ci;
  63         int key, value, match;
  64
  65         match = 0;
  66         fw_csr_iterator_init(&ci, directory);
  67         while (fw_csr_iterator_next(&ci, &key, &value)) {
  68                 if (key == CSR_VENDOR && value == id->vendor)
  69                         match |= FW_MATCH_VENDOR;
  70                 if (key == CSR_MODEL && value == id->model)
  71                         match |= FW_MATCH_MODEL;
  72                 if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
  73                         match |= FW_MATCH_SPECIFIER_ID;
  74                 if (key == CSR_VERSION && value == id->version)
  75                         match |= FW_MATCH_VERSION;
  76         }
  77
  78         return (match & id->match_flags) == id->match_flags;
  79 }
  80
  81 static int fw_unit_match(struct device *dev, struct device_driver *drv)
  82 {
  83         struct fw_unit *unit = fw_unit(dev);
  84         struct fw_driver *driver = fw_driver(drv);
  85         int i;
  86
  87         /* We only allow binding to fw_units. */
  88         if (!is_fw_unit(dev))
  89                 return 0;
  90
  91         for (i = 0; driver->id_table[i].match_flags != 0; i++) {
  92                 if (match_unit_directory(unit->directory, &driver->id_table[i]))
  93                         return 1;
  94         }
  95
  96         return 0;
  97 }
  98
  99 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
 100 {
 101         struct fw_device *device = fw_device(unit->device.parent);
 102         struct fw_csr_iterator ci;
 103
 104         int key, value;
 105         int vendor = 0;
 106         int model = 0;
 107         int specifier_id = 0;
 108         int version = 0;
 109
 110         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 111         while (fw_csr_iterator_next(&ci, &key, &value)) {
 112                 switch (key) {
 113                 case CSR_VENDOR:
 114                         vendor = value;
 115                         break;
 116                 case CSR_MODEL:
 117                         model = value;
 118                         break;
 119                 }
 120         }
 121
 122         fw_csr_iterator_init(&ci, unit->directory);
 123         while (fw_csr_iterator_next(&ci, &key, &value)) {
 124                 switch (key) {
 125                 case CSR_SPECIFIER_ID:
 126                         specifier_id = value;
 127                         break;
 128                 case CSR_VERSION:
 129                         version = value;
 130                         break;
 131                 }
 132         }
 133
 134         return snprintf(buffer, buffer_size,
 135                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
 136                         vendor, model, specifier_id, version);
 137 }
 138
 139 static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 140 {
 141         struct fw_unit *unit = fw_unit(dev);
 142         char modalias[64];
 143
 144         get_modalias(unit, modalias, sizeof(modalias));
 145
 146         if (add_uevent_var(env, "MODALIAS=%s", modalias))
 147                 return -ENOMEM;
 148
 149         return 0;
 150 }
 151
 152 struct bus_type fw_bus_type = {
 153         .name = "firewire",
 154         .match = fw_unit_match,
 155 };
 156 EXPORT_SYMBOL(fw_bus_type);
 157
 158 int fw_device_enable_phys_dma(struct fw_device *device)
 159 {
 160         int generation = device->generation;
 161
 162         /* device->node_id, accessed below, must not be older than generation */
 163         smp_rmb();
 164
 165         return device->card->driver->enable_phys_dma(device->card,
 166                                                      device->node_id,
 167                                                      generation);
 168 }
 169 EXPORT_SYMBOL(fw_device_enable_phys_dma);
 170
 171 struct config_rom_attribute {
 172         struct device_attribute attr;
 173         u32 key;
 174 };
 175
 176 static ssize_t show_immediate(struct device *dev,
 177                               struct device_attribute *dattr, char *buf)
 178 {
 179         struct config_rom_attribute *attr =
 180                 container_of(dattr, struct config_rom_attribute, attr);
 181         struct fw_csr_iterator ci;
 182         u32 *dir;
 183         int key, value, ret = -ENOENT;
 184
 185         down_read(&fw_device_rwsem);
 186
 187         if (is_fw_unit(dev))
 188                 dir = fw_unit(dev)->directory;
 189         else
 190                 dir = fw_device(dev)->config_rom + 5;
 191
 192         fw_csr_iterator_init(&ci, dir);
 193         while (fw_csr_iterator_next(&ci, &key, &value))
 194                 if (attr->key == key) {
 195                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
 196                                        "0x%06x\n", value);
 197                         break;
 198                 }
 199
 200         up_read(&fw_device_rwsem);
 201
 202         return ret;
 203 }
 204
 205 #define IMMEDIATE_ATTR(name, key)                               \
 206         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
 207
 208 static ssize_t show_text_leaf(struct device *dev,
 209                               struct device_attribute *dattr, char *buf)
 210 {
 211         struct config_rom_attribute *attr =
 212                 container_of(dattr, struct config_rom_attribute, attr);
 213         struct fw_csr_iterator ci;
 214         u32 *dir, *block = NULL, *p, *end;
 215         int length, key, value, last_key = 0, ret = -ENOENT;
 216         char *b;
 217
 218         down_read(&fw_device_rwsem);
 219
 220         if (is_fw_unit(dev))
 221                 dir = fw_unit(dev)->directory;
 222         else
 223                 dir = fw_device(dev)->config_rom + 5;
 224
 225         fw_csr_iterator_init(&ci, dir);
 226         while (fw_csr_iterator_next(&ci, &key, &value)) {
 227                 if (attr->key == last_key &&
 228                     key == (CSR_DESCRIPTOR | CSR_LEAF))
 229                         block = ci.p - 1 + value;
 230                 last_key = key;
 231         }
 232
 233         if (block == NULL)
 234                 goto out;
 235
 236         length = min(block[0] >> 16, 256U);
 237         if (length < 3)
 238                 goto out;
 239
 240         if (block[1] != 0 || block[2] != 0)
 241                 /* Unknown encoding. */
 242                 goto out;
 243
 244         if (buf == NULL) {
 245                 ret = length * 4;
 246                 goto out;
 247         }
 248
 249         b = buf;
 250         end = &block[length + 1];
 251         for (p = &block[3]; p < end; p++, b += 4)
 252                 * (u32 *) b = (__force u32) __cpu_to_be32(*p);
 253
 254         /* Strip trailing whitespace and add newline. */
 255         while (b--, (isspace(*b) || *b == '\0') && b > buf);
 256         strcpy(b + 1, "\n");
 257         ret = b + 2 - buf;
 258  out:
 259         up_read(&fw_device_rwsem);
 260
 261         return ret;
 262 }
 263
 264 #define TEXT_LEAF_ATTR(name, key)                               \
 265         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
 266
 267 static struct config_rom_attribute config_rom_attributes[] = {
 268         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
 269         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
 270         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
 271         IMMEDIATE_ATTR(version, CSR_VERSION),
 272         IMMEDIATE_ATTR(model, CSR_MODEL),
 273         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
 274         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
 275         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
 276 };
 277
 278 static void init_fw_attribute_group(struct device *dev,
 279                                     struct device_attribute *attrs,
 280                                     struct fw_attribute_group *group)
 281 {
 282         struct device_attribute *attr;
 283         int i, j;
 284
 285         for (j = 0; attrs[j].attr.name != NULL; j++)
 286                 group->attrs[j] = &attrs[j].attr;
 287
 288         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
 289                 attr = &config_rom_attributes[i].attr;
 290                 if (attr->show(dev, attr, NULL) < 0)
 291                         continue;
 292                 group->attrs[j++] = &attr->attr;
 293         }
 294
 295         BUG_ON(j >= ARRAY_SIZE(group->attrs));
 296         group->attrs[j++] = NULL;
 297         group->groups[0] = &group->group;
 298         group->groups[1] = NULL;
 299         group->group.attrs = group->attrs;
 300         dev->groups = group->groups;
 301 }
 302
 303 static ssize_t modalias_show(struct device *dev,
 304                              struct device_attribute *attr, char *buf)
 305 {
 306         struct fw_unit *unit = fw_unit(dev);
 307         int length;
 308
 309         length = get_modalias(unit, buf, PAGE_SIZE);
 310         strcpy(buf + length, "\n");
 311
 312         return length + 1;
 313 }
 314
 315 static ssize_t rom_index_show(struct device *dev,
 316                               struct device_attribute *attr, char *buf)
 317 {
 318         struct fw_device *device = fw_device(dev->parent);
 319         struct fw_unit *unit = fw_unit(dev);
 320
 321         return snprintf(buf, PAGE_SIZE, "%d\n",
 322                         (int)(unit->directory - device->config_rom));
 323 }
 324
 325 static struct device_attribute fw_unit_attributes[] = {
 326         __ATTR_RO(modalias),
 327         __ATTR_RO(rom_index),
 328         __ATTR_NULL,
 329 };
 330
 331 static ssize_t config_rom_show(struct device *dev,
 332                                struct device_attribute *attr, char *buf)
 333 {
 334         struct fw_device *device = fw_device(dev);
 335         size_t length;
 336
 337         down_read(&fw_device_rwsem);
 338         length = device->config_rom_length * 4;
 339         memcpy(buf, device->config_rom, length);
 340         up_read(&fw_device_rwsem);
 341
 342         return length;
 343 }
 344
 345 static ssize_t guid_show(struct device *dev,
 346                          struct device_attribute *attr, char *buf)
 347 {
 348         struct fw_device *device = fw_device(dev);
 349         int ret;
 350
 351         down_read(&fw_device_rwsem);
 352         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
 353                        device->config_rom[3], device->config_rom[4]);
 354         up_read(&fw_device_rwsem);
 355
 356         return ret;
 357 }
 358
 359 static struct device_attribute fw_device_attributes[] = {
 360         __ATTR_RO(config_rom),
 361         __ATTR_RO(guid),
 362         __ATTR_NULL,
 363 };
 364
 365 static int read_rom(struct fw_device *device,
 366                     int generation, int index, u32 *data)
 367 {
 368         int rcode;
 369
 370         /* device->node_id, accessed below, must not be older than generation */
 371         smp_rmb();
 372
 373         rcode = fw_run_transaction(device->card, TCODE_READ_QUADLET_REQUEST,
 374                         device->node_id, generation, device->max_speed,
 375                         (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4,
 376                         data, 4);
 377         be32_to_cpus(data);
 378
 379         return rcode;
 380 }
 381
 382 #define READ_BIB_ROM_SIZE       256
 383 #define READ_BIB_STACK_SIZE     16
 384
 385 /*
 386  * Read the bus info block, perform a speed probe, and read all of the rest of
 387  * the config ROM.  We do all this with a cached bus generation.  If the bus
 388  * generation changes under us, read_bus_info_block will fail and get retried.
 389  * It's better to start all over in this case because the node from which we
 390  * are reading the ROM may have changed the ROM during the reset.
 391  */
 392 static int read_bus_info_block(struct fw_device *device, int generation)
 393 {
 394         u32 *rom, *stack, *old_rom, *new_rom;
 395         u32 sp, key;
 396         int i, end, length, ret = -1;
 397
 398         rom = kmalloc(sizeof(*rom) * READ_BIB_ROM_SIZE +
 399                       sizeof(*stack) * READ_BIB_STACK_SIZE, GFP_KERNEL);
 400         if (rom == NULL)
 401                 return -ENOMEM;
 402
 403         stack = &rom[READ_BIB_ROM_SIZE];
 404
 405         device->max_speed = SCODE_100;
 406
 407         /* First read the bus info block. */
 408         for (i = 0; i < 5; i++) {
 409                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 410                         goto out;
 411                 /*
 412                  * As per IEEE1212 7.2, during power-up, devices can
 413                  * reply with a 0 for the first quadlet of the config
 414                  * rom to indicate that they are booting (for example,
 415                  * if the firmware is on the disk of a external
 416                  * harddisk).  In that case we just fail, and the
 417                  * retry mechanism will try again later.
 418                  */
 419                 if (i == 0 && rom[i] == 0)
 420                         goto out;
 421         }
 422
 423         device->max_speed = device->node->max_speed;
 424
 425         /*
 426          * Determine the speed of
 427          *   - devices with link speed less than PHY speed,
 428          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
 429          *   - all devices if there are 1394b repeaters.
 430          * Note, we cannot use the bus info block's link_spd as starting point
 431          * because some buggy firmwares set it lower than necessary and because
 432          * 1394-1995 nodes do not have the field.
 433          */
 434         if ((rom[2] & 0x7) < device->max_speed ||
 435             device->max_speed == SCODE_BETA ||
 436             device->card->beta_repeaters_present) {
 437                 u32 dummy;
 438
 439                 /* for S1600 and S3200 */
 440                 if (device->max_speed == SCODE_BETA)
 441                         device->max_speed = device->card->link_speed;
 442
 443                 while (device->max_speed > SCODE_100) {
 444                         if (read_rom(device, generation, 0, &dummy) ==
 445                             RCODE_COMPLETE)
 446                                 break;
 447                         device->max_speed--;
 448                 }
 449         }
 450
 451         /*
 452          * Now parse the config rom.  The config rom is a recursive
 453          * directory structure so we parse it using a stack of
 454          * references to the blocks that make up the structure.  We
 455          * push a reference to the root directory on the stack to
 456          * start things off.
 457          */
 458         length = i;
 459         sp = 0;
 460         stack[sp++] = 0xc0000005;
 461         while (sp > 0) {
 462                 /*
 463                  * Pop the next block reference of the stack.  The
 464                  * lower 24 bits is the offset into the config rom,
 465                  * the upper 8 bits are the type of the reference the
 466                  * block.
 467                  */
 468                 key = stack[--sp];
 469                 i = key & 0xffffff;
 470                 if (i >= READ_BIB_ROM_SIZE)
 471                         /*
 472                          * The reference points outside the standard
 473                          * config rom area, something's fishy.
 474                          */
 475                         goto out;
 476
 477                 /* Read header quadlet for the block to get the length. */
 478                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 479                         goto out;
 480                 end = i + (rom[i] >> 16) + 1;
 481                 i++;
 482                 if (end > READ_BIB_ROM_SIZE)
 483                         /*
 484                          * This block extends outside standard config
 485                          * area (and the array we're reading it
 486                          * into).  That's broken, so ignore this
 487                          * device.
 488                          */
 489                         goto out;
 490
 491                 /*
 492                  * Now read in the block.  If this is a directory
 493                  * block, check the entries as we read them to see if
 494                  * it references another block, and push it in that case.
 495                  */
 496                 while (i < end) {
 497                         if (read_rom(device, generation, i, &rom[i]) !=
 498                             RCODE_COMPLETE)
 499                                 goto out;
 500                         if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
 501                             sp < READ_BIB_STACK_SIZE)
 502                                 stack[sp++] = i + rom[i];
 503                         i++;
 504                 }
 505                 if (length < i)
 506                         length = i;
 507         }
 508
 509         old_rom = device->config_rom;
 510         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
 511         if (new_rom == NULL)
 512                 goto out;
 513
 514         down_write(&fw_device_rwsem);
 515         device->config_rom = new_rom;
 516         device->config_rom_length = length;
 517         up_write(&fw_device_rwsem);
 518
 519         kfree(old_rom);
 520         ret = 0;
 521         device->cmc = rom[2] >> 30 & 1;
 522  out:
 523         kfree(rom);
 524
 525         return ret;
 526 }
 527
 528 static void fw_unit_release(struct device *dev)
 529 {
 530         struct fw_unit *unit = fw_unit(dev);
 531
 532         kfree(unit);
 533 }
 534
 535 static struct device_type fw_unit_type = {
 536         .uevent         = fw_unit_uevent,
 537         .release        = fw_unit_release,
 538 };
 539
 540 static int is_fw_unit(struct device *dev)
 541 {
 542         return dev->type == &fw_unit_type;
 543 }
 544
 545 static void create_units(struct fw_device *device)
 546 {
 547         struct fw_csr_iterator ci;
 548         struct fw_unit *unit;
 549         int key, value, i;
 550
 551         i = 0;
 552         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 553         while (fw_csr_iterator_next(&ci, &key, &value)) {
 554                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 555                         continue;
 556
 557                 /*
 558                  * Get the address of the unit directory and try to
 559                  * match the drivers id_tables against it.
 560                  */
 561                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 562                 if (unit == NULL) {
 563                         fw_error("failed to allocate memory for unit\n");
 564                         continue;
 565                 }
 566
 567                 unit->directory = ci.p + value - 1;
 568                 unit->device.bus = &fw_bus_type;
 569                 unit->device.type = &fw_unit_type;
 570                 unit->device.parent = &device->device;
 571                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
 572
 573                 init_fw_attribute_group(&unit->device,
 574                                         fw_unit_attributes,
 575                                         &unit->attribute_group);
 576                 if (device_register(&unit->device) < 0)
 577                         goto skip_unit;
 578
 579                 continue;
 580
 581         skip_unit:
 582                 kfree(unit);
 583         }
 584 }
 585
 586 static int shutdown_unit(struct device *device, void *data)
 587 {
 588         device_unregister(device);
 589
 590         return 0;
 591 }
 592
 593 /*
 594  * fw_device_rwsem acts as dual purpose mutex:
 595  *   - serializes accesses to fw_device_idr,
 596  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 597  *     fw_unit.directory, unless those accesses happen at safe occasions
 598  */
 599 DECLARE_RWSEM(fw_device_rwsem);
 600
 601 DEFINE_IDR(fw_device_idr);
 602 int fw_cdev_major;
 603
 604 struct fw_device *fw_device_get_by_devt(dev_t devt)
 605 {
 606         struct fw_device *device;
 607
 608         down_read(&fw_device_rwsem);
 609         device = idr_find(&fw_device_idr, MINOR(devt));
 610         if (device)
 611                 fw_device_get(device);
 612         up_read(&fw_device_rwsem);
 613
 614         return device;
 615 }
 616
 617 /*
 618  * These defines control the retry behavior for reading the config
 619  * rom.  It shouldn't be necessary to tweak these; if the device
 620  * doesn't respond to a config rom read within 10 seconds, it's not
 621  * going to respond at all.  As for the initial delay, a lot of
 622  * devices will be able to respond within half a second after bus
 623  * reset.  On the other hand, it's not really worth being more
 624  * aggressive than that, since it scales pretty well; if 10 devices
 625  * are plugged in, they're all getting read within one second.
 626  */
 627
 628 #define MAX_RETRIES     10
 629 #define RETRY_DELAY     (3 * HZ)
 630 #define INITIAL_DELAY   (HZ / 2)
 631 #define SHUTDOWN_DELAY  (2 * HZ)
 632
 633 static void fw_device_shutdown(struct work_struct *work)
 634 {
 635         struct fw_device *device =
 636                 container_of(work, struct fw_device, work.work);
 637         int minor = MINOR(device->device.devt);
 638
 639         if (time_is_after_jiffies(device->card->reset_jiffies + SHUTDOWN_DELAY)
 640             && !list_empty(&device->card->link)) {
 641                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 642                 return;
 643         }
 644
 645         if (atomic_cmpxchg(&device->state,
 646                            FW_DEVICE_GONE,
 647                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
 648                 return;
 649
 650         fw_device_cdev_remove(device);
 651         device_for_each_child(&device->device, NULL, shutdown_unit);
 652         device_unregister(&device->device);
 653
 654         down_write(&fw_device_rwsem);
 655         idr_remove(&fw_device_idr, minor);
 656         up_write(&fw_device_rwsem);
 657
 658         fw_device_put(device);
 659 }
 660
 661 static void fw_device_release(struct device *dev)
 662 {
 663         struct fw_device *device = fw_device(dev);
 664         struct fw_card *card = device->card;
 665         unsigned long flags;
 666
 667         /*
 668          * Take the card lock so we don't set this to NULL while a
 669          * FW_NODE_UPDATED callback is being handled or while the
 670          * bus manager work looks at this node.
 671          */
 672         spin_lock_irqsave(&card->lock, flags);
 673         device->node->data = NULL;
 674         spin_unlock_irqrestore(&card->lock, flags);
 675
 676         fw_node_put(device->node);
 677         kfree(device->config_rom);
 678         kfree(device);
 679         fw_card_put(card);
 680 }
 681
 682 static struct device_type fw_device_type = {
 683         .release = fw_device_release,
 684 };
 685
 686 static int update_unit(struct device *dev, void *data)
 687 {
 688         struct fw_unit *unit = fw_unit(dev);
 689         struct fw_driver *driver = (struct fw_driver *)dev->driver;
 690
 691         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
 692                 down(&dev->sem);
 693                 driver->update(unit);
 694                 up(&dev->sem);
 695         }
 696
 697         return 0;
 698 }
 699
 700 static void fw_device_update(struct work_struct *work)
 701 {
 702         struct fw_device *device =
 703                 container_of(work, struct fw_device, work.work);
 704
 705         fw_device_cdev_update(device);
 706         device_for_each_child(&device->device, NULL, update_unit);
 707 }
 708
 709 /*
 710  * If a device was pending for deletion because its node went away but its
 711  * bus info block and root directory header matches that of a newly discovered
 712  * device, revive the existing fw_device.
 713  * The newly allocated fw_device becomes obsolete instead.
 714  */
 715 static int lookup_existing_device(struct device *dev, void *data)
 716 {
 717         struct fw_device *old = fw_device(dev);
 718         struct fw_device *new = data;
 719         struct fw_card *card = new->card;
 720         int match = 0;
 721
 722         down_read(&fw_device_rwsem); /* serialize config_rom access */
 723         spin_lock_irq(&card->lock);  /* serialize node access */
 724
 725         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
 726             atomic_cmpxchg(&old->state,
 727                            FW_DEVICE_GONE,
 728                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 729                 struct fw_node *current_node = new->node;
 730                 struct fw_node *obsolete_node = old->node;
 731
 732                 new->node = obsolete_node;
 733                 new->node->data = new;
 734                 old->node = current_node;
 735                 old->node->data = old;
 736
 737                 old->max_speed = new->max_speed;
 738                 old->node_id = current_node->node_id;
 739                 smp_wmb();  /* update node_id before generation */
 740                 old->generation = card->generation;
 741                 old->config_rom_retries = 0;
 742                 fw_notify("rediscovered device %s\n", dev_name(dev));
 743
 744                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
 745                 schedule_delayed_work(&old->work, 0);
 746
 747                 if (current_node == card->root_node)
 748                         fw_schedule_bm_work(card, 0);
 749
 750                 match = 1;
 751         }
 752
 753         spin_unlock_irq(&card->lock);
 754         up_read(&fw_device_rwsem);
 755
 756         return match;
 757 }
 758
 759 enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
 760
 761 void fw_device_set_broadcast_channel(struct fw_device *device, int generation)
 762 {
 763         struct fw_card *card = device->card;
 764         __be32 data;
 765         int rcode;
 766
 767         if (!card->broadcast_channel_allocated)
 768                 return;
 769
 770         if (device->bc_implemented == BC_UNKNOWN) {
 771                 rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
 772                                 device->node_id, generation, device->max_speed,
 773                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 774                                 &data, 4);
 775                 switch (rcode) {
 776                 case RCODE_COMPLETE:
 777                         if (data & cpu_to_be32(1 << 31)) {
 778                                 device->bc_implemented = BC_IMPLEMENTED;
 779                                 break;
 780                         }
 781                         /* else fall through to case address error */
 782                 case RCODE_ADDRESS_ERROR:
 783                         device->bc_implemented = BC_UNIMPLEMENTED;
 784                 }
 785         }
 786
 787         if (device->bc_implemented == BC_IMPLEMENTED) {
 788                 data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
 789                                    BROADCAST_CHANNEL_VALID);
 790                 fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
 791                                 device->node_id, generation, device->max_speed,
 792                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 793                                 &data, 4);
 794         }
 795 }
 796
 797 static void fw_device_init(struct work_struct *work)
 798 {
 799         struct fw_device *device =
 800                 container_of(work, struct fw_device, work.work);
 801         struct device *revived_dev;
 802         int minor, ret;
 803
 804         /*
 805          * All failure paths here set node->data to NULL, so that we
 806          * don't try to do device_for_each_child() on a kfree()'d
 807          * device.
 808          */
 809
 810         if (read_bus_info_block(device, device->generation) < 0) {
 811                 if (device->config_rom_retries < MAX_RETRIES &&
 812                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 813                         device->config_rom_retries++;
 814                         schedule_delayed_work(&device->work, RETRY_DELAY);
 815                 } else {
 816                         fw_notify("giving up on config rom for node id %x\n",
 817                                   device->node_id);
 818                         if (device->node == device->card->root_node)
 819                                 fw_schedule_bm_work(device->card, 0);
 820                         fw_device_release(&device->device);
 821                 }
 822                 return;
 823         }
 824
 825         revived_dev = device_find_child(device->card->device,
 826                                         device, lookup_existing_device);
 827         if (revived_dev) {
 828                 put_device(revived_dev);
 829                 fw_device_release(&device->device);
 830
 831                 return;
 832         }
 833
 834         device_initialize(&device->device);
 835
 836         fw_device_get(device);
 837         down_write(&fw_device_rwsem);
 838         ret = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
 839               idr_get_new(&fw_device_idr, device, &minor) :
 840               -ENOMEM;
 841         up_write(&fw_device_rwsem);
 842
 843         if (ret < 0)
 844                 goto error;
 845
 846         device->device.bus = &fw_bus_type;
 847         device->device.type = &fw_device_type;
 848         device->device.parent = device->card->device;
 849         device->device.devt = MKDEV(fw_cdev_major, minor);
 850         dev_set_name(&device->device, "fw%d", minor);
 851
 852         init_fw_attribute_group(&device->device,
 853                                 fw_device_attributes,
 854                                 &device->attribute_group);
 855         if (device_add(&device->device)) {
 856                 fw_error("Failed to add device.\n");
 857                 goto error_with_cdev;
 858         }
 859
 860         create_units(device);
 861
 862         /*
 863          * Transition the device to running state.  If it got pulled
 864          * out from under us while we did the intialization work, we
 865          * have to shut down the device again here.  Normally, though,
 866          * fw_node_event will be responsible for shutting it down when
 867          * necessary.  We have to use the atomic cmpxchg here to avoid
 868          * racing with the FW_NODE_DESTROYED case in
 869          * fw_node_event().
 870          */
 871         if (atomic_cmpxchg(&device->state,
 872                            FW_DEVICE_INITIALIZING,
 873                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 874                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
 875                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 876         } else {
 877                 if (device->config_rom_retries)
 878                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
 879                                   "%d config ROM retries\n",
 880                                   dev_name(&device->device),
 881                                   device->config_rom[3], device->config_rom[4],
 882                                   1 << device->max_speed,
 883                                   device->config_rom_retries);
 884                 else
 885                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
 886                                   dev_name(&device->device),
 887                                   device->config_rom[3], device->config_rom[4],
 888                                   1 << device->max_speed);
 889                 device->config_rom_retries = 0;
 890
 891                 fw_device_set_broadcast_channel(device, device->generation);
 892         }
 893
 894         /*
 895          * Reschedule the IRM work if we just finished reading the
 896          * root node config rom.  If this races with a bus reset we
 897          * just end up running the IRM work a couple of extra times -
 898          * pretty harmless.
 899          */
 900         if (device->node == device->card->root_node)
 901                 fw_schedule_bm_work(device->card, 0);
 902
 903         return;
 904
 905  error_with_cdev:
 906         down_write(&fw_device_rwsem);
 907         idr_remove(&fw_device_idr, minor);
 908         up_write(&fw_device_rwsem);
 909  error:
 910         fw_device_put(device);          /* fw_device_idr's reference */
 911
 912         put_device(&device->device);    /* our reference */
 913 }
 914
 915 enum {
 916         REREAD_BIB_ERROR,
 917         REREAD_BIB_GONE,
 918         REREAD_BIB_UNCHANGED,
 919         REREAD_BIB_CHANGED,
 920 };
 921
 922 /* Reread and compare bus info block and header of root directory */
 923 static int reread_bus_info_block(struct fw_device *device, int generation)
 924 {
 925         u32 q;
 926         int i;
 927
 928         for (i = 0; i < 6; i++) {
 929                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
 930                         return REREAD_BIB_ERROR;
 931
 932                 if (i == 0 && q == 0)
 933                         return REREAD_BIB_GONE;
 934
 935                 if (q != device->config_rom[i])
 936                         return REREAD_BIB_CHANGED;
 937         }
 938
 939         return REREAD_BIB_UNCHANGED;
 940 }
 941
 942 static void fw_device_refresh(struct work_struct *work)
 943 {
 944         struct fw_device *device =
 945                 container_of(work, struct fw_device, work.work);
 946         struct fw_card *card = device->card;
 947         int node_id = device->node_id;
 948
 949         switch (reread_bus_info_block(device, device->generation)) {
 950         case REREAD_BIB_ERROR:
 951                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
 952                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 953                         device->config_rom_retries++;
 954                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
 955
 956                         return;
 957                 }
 958                 goto give_up;
 959
 960         case REREAD_BIB_GONE:
 961                 goto gone;
 962
 963         case REREAD_BIB_UNCHANGED:
 964                 if (atomic_cmpxchg(&device->state,
 965                                    FW_DEVICE_INITIALIZING,
 966                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
 967                         goto gone;
 968
 969                 fw_device_update(work);
 970                 device->config_rom_retries = 0;
 971                 goto out;
 972
 973         case REREAD_BIB_CHANGED:
 974                 break;
 975         }
 976
 977         /*
 978          * Something changed.  We keep things simple and don't investigate
 979          * further.  We just destroy all previous units and create new ones.
 980          */
 981         device_for_each_child(&device->device, NULL, shutdown_unit);
 982
 983         if (read_bus_info_block(device, device->generation) < 0) {
 984                 if (device->config_rom_retries < MAX_RETRIES &&
 985                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 986                         device->config_rom_retries++;
 987                         schedule_delayed_work(&device->work, RETRY_DELAY);
 988
 989                         return;
 990                 }
 991                 goto give_up;
 992         }
 993
 994         create_units(device);
 995
 996         if (atomic_cmpxchg(&device->state,
 997                            FW_DEVICE_INITIALIZING,
 998                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
 999                 goto gone;
1000
1001         fw_notify("refreshed device %s\n", dev_name(&device->device));
1002         device->config_rom_retries = 0;
1003         goto out;
1004
1005  give_up:
1006         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
1007  gone:
1008         atomic_set(&device->state, FW_DEVICE_GONE);
1009         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1010         schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
1011  out:
1012         if (node_id == card->root_node->node_id)
1013                 fw_schedule_bm_work(card, 0);
1014 }
1015
1016 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1017 {
1018         struct fw_device *device;
1019
1020         switch (event) {
1021         case FW_NODE_CREATED:
1022         case FW_NODE_LINK_ON:
1023                 if (!node->link_on)
1024                         break;
1025  create:
1026                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
1027                 if (device == NULL)
1028                         break;
1029
1030                 /*
1031                  * Do minimal intialization of the device here, the
1032                  * rest will happen in fw_device_init().
1033                  *
1034                  * Attention:  A lot of things, even fw_device_get(),
1035                  * cannot be done before fw_device_init() finished!
1036                  * You can basically just check device->state and
1037                  * schedule work until then, but only while holding
1038                  * card->lock.
1039                  */
1040                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1041                 device->card = fw_card_get(card);
1042                 device->node = fw_node_get(node);
1043                 device->node_id = node->node_id;
1044                 device->generation = card->generation;
1045                 mutex_init(&device->client_list_mutex);
1046                 INIT_LIST_HEAD(&device->client_list);
1047
1048                 /*
1049                  * Set the node data to point back to this device so
1050                  * FW_NODE_UPDATED callbacks can update the node_id
1051                  * and generation for the device.
1052                  */
1053                 node->data = device;
1054
1055                 /*
1056                  * Many devices are slow to respond after bus resets,
1057                  * especially if they are bus powered and go through
1058                  * power-up after getting plugged in.  We schedule the
1059                  * first config rom scan half a second after bus reset.
1060                  */
1061                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1062                 schedule_delayed_work(&device->work, INITIAL_DELAY);
1063                 break;
1064
1065         case FW_NODE_INITIATED_RESET:
1066                 device = node->data;
1067                 if (device == NULL)
1068                         goto create;
1069
1070                 device->node_id = node->node_id;
1071                 smp_wmb();  /* update node_id before generation */
1072                 device->generation = card->generation;
1073                 if (atomic_cmpxchg(&device->state,
1074                             FW_DEVICE_RUNNING,
1075                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1076                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1077                         schedule_delayed_work(&device->work,
1078                                 node == card->local_node ? 0 : INITIAL_DELAY);
1079                 }
1080                 break;
1081
1082         case FW_NODE_UPDATED:
1083                 if (!node->link_on || node->data == NULL)
1084                         break;
1085
1086                 device = node->data;
1087                 device->node_id = node->node_id;
1088                 smp_wmb();  /* update node_id before generation */
1089                 device->generation = card->generation;
1090                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1091                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1092                         schedule_delayed_work(&device->work, 0);
1093                 }
1094                 break;
1095
1096         case FW_NODE_DESTROYED:
1097         case FW_NODE_LINK_OFF:
1098                 if (!node->data)
1099                         break;
1100
1101                 /*
1102                  * Destroy the device associated with the node.  There
1103                  * are two cases here: either the device is fully
1104                  * initialized (FW_DEVICE_RUNNING) or we're in the
1105                  * process of reading its config rom
1106                  * (FW_DEVICE_INITIALIZING).  If it is fully
1107                  * initialized we can reuse device->work to schedule a
1108                  * full fw_device_shutdown().  If not, there's work
1109                  * scheduled to read it's config rom, and we just put
1110                  * the device in shutdown state to have that code fail
1111                  * to create the device.
1112                  */
1113                 device = node->data;
1114                 if (atomic_xchg(&device->state,
1115                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1116                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1117                         schedule_delayed_work(&device->work,
1118                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1119                 }
1120                 break;
1121         }
1122 }