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         fw_card_put(card);
 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 static int
 385 read_rom(struct fw_device *device, int generation, int index, u32 *data)
 386 {
 387         int rcode;
 388
 389         /* device->node_id, accessed below, must not be older than generation */
 390         smp_rmb();
 391
 392         rcode = fw_run_transaction(device->card, TCODE_READ_QUADLET_REQUEST,
 393                         device->node_id, generation, device->max_speed,
 394                         (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4,
 395                         data, 4);
 396         be32_to_cpus(data);
 397
 398         return rcode;
 399 }
 400
 401 #define READ_BIB_ROM_SIZE       256
 402 #define READ_BIB_STACK_SIZE     16
 403
 404 /*
 405  * Read the bus info block, perform a speed probe, and read all of the rest of
 406  * the config ROM.  We do all this with a cached bus generation.  If the bus
 407  * generation changes under us, read_bus_info_block will fail and get retried.
 408  * It's better to start all over in this case because the node from which we
 409  * are reading the ROM may have changed the ROM during the reset.
 410  */
 411 static int read_bus_info_block(struct fw_device *device, int generation)
 412 {
 413         u32 *rom, *stack, *old_rom, *new_rom;
 414         u32 sp, key;
 415         int i, end, length, ret = -1;
 416
 417         rom = kmalloc(sizeof(*rom) * READ_BIB_ROM_SIZE +
 418                       sizeof(*stack) * READ_BIB_STACK_SIZE, GFP_KERNEL);
 419         if (rom == NULL)
 420                 return -ENOMEM;
 421
 422         stack = &rom[READ_BIB_ROM_SIZE];
 423
 424         device->max_speed = SCODE_100;
 425
 426         /* First read the bus info block. */
 427         for (i = 0; i < 5; i++) {
 428                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 429                         goto out;
 430                 /*
 431                  * As per IEEE1212 7.2, during power-up, devices can
 432                  * reply with a 0 for the first quadlet of the config
 433                  * rom to indicate that they are booting (for example,
 434                  * if the firmware is on the disk of a external
 435                  * harddisk).  In that case we just fail, and the
 436                  * retry mechanism will try again later.
 437                  */
 438                 if (i == 0 && rom[i] == 0)
 439                         goto out;
 440         }
 441
 442         device->max_speed = device->node->max_speed;
 443
 444         /*
 445          * Determine the speed of
 446          *   - devices with link speed less than PHY speed,
 447          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
 448          *   - all devices if there are 1394b repeaters.
 449          * Note, we cannot use the bus info block's link_spd as starting point
 450          * because some buggy firmwares set it lower than necessary and because
 451          * 1394-1995 nodes do not have the field.
 452          */
 453         if ((rom[2] & 0x7) < device->max_speed ||
 454             device->max_speed == SCODE_BETA ||
 455             device->card->beta_repeaters_present) {
 456                 u32 dummy;
 457
 458                 /* for S1600 and S3200 */
 459                 if (device->max_speed == SCODE_BETA)
 460                         device->max_speed = device->card->link_speed;
 461
 462                 while (device->max_speed > SCODE_100) {
 463                         if (read_rom(device, generation, 0, &dummy) ==
 464                             RCODE_COMPLETE)
 465                                 break;
 466                         device->max_speed--;
 467                 }
 468         }
 469
 470         /*
 471          * Now parse the config rom.  The config rom is a recursive
 472          * directory structure so we parse it using a stack of
 473          * references to the blocks that make up the structure.  We
 474          * push a reference to the root directory on the stack to
 475          * start things off.
 476          */
 477         length = i;
 478         sp = 0;
 479         stack[sp++] = 0xc0000005;
 480         while (sp > 0) {
 481                 /*
 482                  * Pop the next block reference of the stack.  The
 483                  * lower 24 bits is the offset into the config rom,
 484                  * the upper 8 bits are the type of the reference the
 485                  * block.
 486                  */
 487                 key = stack[--sp];
 488                 i = key & 0xffffff;
 489                 if (i >= READ_BIB_ROM_SIZE)
 490                         /*
 491                          * The reference points outside the standard
 492                          * config rom area, something's fishy.
 493                          */
 494                         goto out;
 495
 496                 /* Read header quadlet for the block to get the length. */
 497                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 498                         goto out;
 499                 end = i + (rom[i] >> 16) + 1;
 500                 i++;
 501                 if (end > READ_BIB_ROM_SIZE)
 502                         /*
 503                          * This block extends outside standard config
 504                          * area (and the array we're reading it
 505                          * into).  That's broken, so ignore this
 506                          * device.
 507                          */
 508                         goto out;
 509
 510                 /*
 511                  * Now read in the block.  If this is a directory
 512                  * block, check the entries as we read them to see if
 513                  * it references another block, and push it in that case.
 514                  */
 515                 while (i < end) {
 516                         if (read_rom(device, generation, i, &rom[i]) !=
 517                             RCODE_COMPLETE)
 518                                 goto out;
 519                         if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
 520                             sp < READ_BIB_STACK_SIZE)
 521                                 stack[sp++] = i + rom[i];
 522                         i++;
 523                 }
 524                 if (length < i)
 525                         length = i;
 526         }
 527
 528         old_rom = device->config_rom;
 529         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
 530         if (new_rom == NULL)
 531                 goto out;
 532
 533         down_write(&fw_device_rwsem);
 534         device->config_rom = new_rom;
 535         device->config_rom_length = length;
 536         up_write(&fw_device_rwsem);
 537
 538         kfree(old_rom);
 539         ret = 0;
 540         device->cmc = rom[2] & 1 << 30;
 541  out:
 542         kfree(rom);
 543
 544         return ret;
 545 }
 546
 547 static void fw_unit_release(struct device *dev)
 548 {
 549         struct fw_unit *unit = fw_unit(dev);
 550
 551         kfree(unit);
 552 }
 553
 554 static struct device_type fw_unit_type = {
 555         .uevent         = fw_unit_uevent,
 556         .release        = fw_unit_release,
 557 };
 558
 559 static int is_fw_unit(struct device *dev)
 560 {
 561         return dev->type == &fw_unit_type;
 562 }
 563
 564 static void create_units(struct fw_device *device)
 565 {
 566         struct fw_csr_iterator ci;
 567         struct fw_unit *unit;
 568         int key, value, i;
 569
 570         i = 0;
 571         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 572         while (fw_csr_iterator_next(&ci, &key, &value)) {
 573                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 574                         continue;
 575
 576                 /*
 577                  * Get the address of the unit directory and try to
 578                  * match the drivers id_tables against it.
 579                  */
 580                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 581                 if (unit == NULL) {
 582                         fw_error("failed to allocate memory for unit\n");
 583                         continue;
 584                 }
 585
 586                 unit->directory = ci.p + value - 1;
 587                 unit->device.bus = &fw_bus_type;
 588                 unit->device.type = &fw_unit_type;
 589                 unit->device.parent = &device->device;
 590                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
 591
 592                 init_fw_attribute_group(&unit->device,
 593                                         fw_unit_attributes,
 594                                         &unit->attribute_group);
 595                 if (device_register(&unit->device) < 0)
 596                         goto skip_unit;
 597
 598                 continue;
 599
 600         skip_unit:
 601                 kfree(unit);
 602         }
 603 }
 604
 605 static int shutdown_unit(struct device *device, void *data)
 606 {
 607         device_unregister(device);
 608
 609         return 0;
 610 }
 611
 612 /*
 613  * fw_device_rwsem acts as dual purpose mutex:
 614  *   - serializes accesses to fw_device_idr,
 615  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 616  *     fw_unit.directory, unless those accesses happen at safe occasions
 617  */
 618 DECLARE_RWSEM(fw_device_rwsem);
 619
 620 DEFINE_IDR(fw_device_idr);
 621 int fw_cdev_major;
 622
 623 struct fw_device *fw_device_get_by_devt(dev_t devt)
 624 {
 625         struct fw_device *device;
 626
 627         down_read(&fw_device_rwsem);
 628         device = idr_find(&fw_device_idr, MINOR(devt));
 629         if (device)
 630                 fw_device_get(device);
 631         up_read(&fw_device_rwsem);
 632
 633         return device;
 634 }
 635
 636 static void fw_device_shutdown(struct work_struct *work)
 637 {
 638         struct fw_device *device =
 639                 container_of(work, struct fw_device, work.work);
 640         int minor = MINOR(device->device.devt);
 641
 642         fw_device_cdev_remove(device);
 643         device_for_each_child(&device->device, NULL, shutdown_unit);
 644         device_unregister(&device->device);
 645
 646         down_write(&fw_device_rwsem);
 647         idr_remove(&fw_device_idr, minor);
 648         up_write(&fw_device_rwsem);
 649         fw_device_put(device);
 650 }
 651
 652 static struct device_type fw_device_type = {
 653         .release        = fw_device_release,
 654 };
 655
 656 /*
 657  * These defines control the retry behavior for reading the config
 658  * rom.  It shouldn't be necessary to tweak these; if the device
 659  * doesn't respond to a config rom read within 10 seconds, it's not
 660  * going to respond at all.  As for the initial delay, a lot of
 661  * devices will be able to respond within half a second after bus
 662  * reset.  On the other hand, it's not really worth being more
 663  * aggressive than that, since it scales pretty well; if 10 devices
 664  * are plugged in, they're all getting read within one second.
 665  */
 666
 667 #define MAX_RETRIES     10
 668 #define RETRY_DELAY     (3 * HZ)
 669 #define INITIAL_DELAY   (HZ / 2)
 670
 671 static void fw_device_init(struct work_struct *work)
 672 {
 673         struct fw_device *device =
 674                 container_of(work, struct fw_device, work.work);
 675         int minor, err;
 676
 677         /*
 678          * All failure paths here set node->data to NULL, so that we
 679          * don't try to do device_for_each_child() on a kfree()'d
 680          * device.
 681          */
 682
 683         if (read_bus_info_block(device, device->generation) < 0) {
 684                 if (device->config_rom_retries < MAX_RETRIES &&
 685                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 686                         device->config_rom_retries++;
 687                         schedule_delayed_work(&device->work, RETRY_DELAY);
 688                 } else {
 689                         fw_notify("giving up on config rom for node id %x\n",
 690                                   device->node_id);
 691                         if (device->node == device->card->root_node)
 692                                 fw_schedule_bm_work(device->card, 0);
 693                         fw_device_release(&device->device);
 694                 }
 695                 return;
 696         }
 697
 698         err = -ENOMEM;
 699
 700         fw_device_get(device);
 701         down_write(&fw_device_rwsem);
 702         if (idr_pre_get(&fw_device_idr, GFP_KERNEL))
 703                 err = idr_get_new(&fw_device_idr, device, &minor);
 704         up_write(&fw_device_rwsem);
 705
 706         if (err < 0)
 707                 goto error;
 708
 709         device->device.bus = &fw_bus_type;
 710         device->device.type = &fw_device_type;
 711         device->device.parent = device->card->device;
 712         device->device.devt = MKDEV(fw_cdev_major, minor);
 713         dev_set_name(&device->device, "fw%d", minor);
 714
 715         init_fw_attribute_group(&device->device,
 716                                 fw_device_attributes,
 717                                 &device->attribute_group);
 718         if (device_add(&device->device)) {
 719                 fw_error("Failed to add device.\n");
 720                 goto error_with_cdev;
 721         }
 722
 723         create_units(device);
 724
 725         /*
 726          * Transition the device to running state.  If it got pulled
 727          * out from under us while we did the intialization work, we
 728          * have to shut down the device again here.  Normally, though,
 729          * fw_node_event will be responsible for shutting it down when
 730          * necessary.  We have to use the atomic cmpxchg here to avoid
 731          * racing with the FW_NODE_DESTROYED case in
 732          * fw_node_event().
 733          */
 734         if (atomic_cmpxchg(&device->state,
 735                     FW_DEVICE_INITIALIZING,
 736                     FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN) {
 737                 fw_device_shutdown(work);
 738         } else {
 739                 if (device->config_rom_retries)
 740                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
 741                                   "%d config ROM retries\n",
 742                                   dev_name(&device->device),
 743                                   device->config_rom[3], device->config_rom[4],
 744                                   1 << device->max_speed,
 745                                   device->config_rom_retries);
 746                 else
 747                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
 748                                   dev_name(&device->device),
 749                                   device->config_rom[3], device->config_rom[4],
 750                                   1 << device->max_speed);
 751                 device->config_rom_retries = 0;
 752         }
 753
 754         /*
 755          * Reschedule the IRM work if we just finished reading the
 756          * root node config rom.  If this races with a bus reset we
 757          * just end up running the IRM work a couple of extra times -
 758          * pretty harmless.
 759          */
 760         if (device->node == device->card->root_node)
 761                 fw_schedule_bm_work(device->card, 0);
 762
 763         return;
 764
 765  error_with_cdev:
 766         down_write(&fw_device_rwsem);
 767         idr_remove(&fw_device_idr, minor);
 768         up_write(&fw_device_rwsem);
 769  error:
 770         fw_device_put(device);          /* fw_device_idr's reference */
 771
 772         put_device(&device->device);    /* our reference */
 773 }
 774
 775 static int update_unit(struct device *dev, void *data)
 776 {
 777         struct fw_unit *unit = fw_unit(dev);
 778         struct fw_driver *driver = (struct fw_driver *)dev->driver;
 779
 780         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
 781                 down(&dev->sem);
 782                 driver->update(unit);
 783                 up(&dev->sem);
 784         }
 785
 786         return 0;
 787 }
 788
 789 static void fw_device_update(struct work_struct *work)
 790 {
 791         struct fw_device *device =
 792                 container_of(work, struct fw_device, work.work);
 793
 794         fw_device_cdev_update(device);
 795         device_for_each_child(&device->device, NULL, update_unit);
 796 }
 797
 798 enum {
 799         REREAD_BIB_ERROR,
 800         REREAD_BIB_GONE,
 801         REREAD_BIB_UNCHANGED,
 802         REREAD_BIB_CHANGED,
 803 };
 804
 805 /* Reread and compare bus info block and header of root directory */
 806 static int reread_bus_info_block(struct fw_device *device, int generation)
 807 {
 808         u32 q;
 809         int i;
 810
 811         for (i = 0; i < 6; i++) {
 812                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
 813                         return REREAD_BIB_ERROR;
 814
 815                 if (i == 0 && q == 0)
 816                         return REREAD_BIB_GONE;
 817
 818                 if (i > device->config_rom_length || q != device->config_rom[i])
 819                         return REREAD_BIB_CHANGED;
 820         }
 821
 822         return REREAD_BIB_UNCHANGED;
 823 }
 824
 825 static void fw_device_refresh(struct work_struct *work)
 826 {
 827         struct fw_device *device =
 828                 container_of(work, struct fw_device, work.work);
 829         struct fw_card *card = device->card;
 830         int node_id = device->node_id;
 831
 832         switch (reread_bus_info_block(device, device->generation)) {
 833         case REREAD_BIB_ERROR:
 834                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
 835                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 836                         device->config_rom_retries++;
 837                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
 838
 839                         return;
 840                 }
 841                 goto give_up;
 842
 843         case REREAD_BIB_GONE:
 844                 goto gone;
 845
 846         case REREAD_BIB_UNCHANGED:
 847                 if (atomic_cmpxchg(&device->state,
 848                             FW_DEVICE_INITIALIZING,
 849                             FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
 850                         goto gone;
 851
 852                 fw_device_update(work);
 853                 device->config_rom_retries = 0;
 854                 goto out;
 855
 856         case REREAD_BIB_CHANGED:
 857                 break;
 858         }
 859
 860         /*
 861          * Something changed.  We keep things simple and don't investigate
 862          * further.  We just destroy all previous units and create new ones.
 863          */
 864         device_for_each_child(&device->device, NULL, shutdown_unit);
 865
 866         if (read_bus_info_block(device, device->generation) < 0) {
 867                 if (device->config_rom_retries < MAX_RETRIES &&
 868                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 869                         device->config_rom_retries++;
 870                         schedule_delayed_work(&device->work, RETRY_DELAY);
 871
 872                         return;
 873                 }
 874                 goto give_up;
 875         }
 876
 877         create_units(device);
 878
 879         if (atomic_cmpxchg(&device->state,
 880                     FW_DEVICE_INITIALIZING,
 881                     FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
 882                 goto gone;
 883
 884         fw_notify("refreshed device %s\n", dev_name(&device->device));
 885         device->config_rom_retries = 0;
 886         goto out;
 887
 888  give_up:
 889         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
 890  gone:
 891         atomic_set(&device->state, FW_DEVICE_SHUTDOWN);
 892         fw_device_shutdown(work);
 893  out:
 894         if (node_id == card->root_node->node_id)
 895                 fw_schedule_bm_work(card, 0);
 896 }
 897
 898 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
 899 {
 900         struct fw_device *device;
 901
 902         switch (event) {
 903         case FW_NODE_CREATED:
 904         case FW_NODE_LINK_ON:
 905                 if (!node->link_on)
 906                         break;
 907  create:
 908                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
 909                 if (device == NULL)
 910                         break;
 911
 912                 /*
 913                  * Do minimal intialization of the device here, the
 914                  * rest will happen in fw_device_init().  We need the
 915                  * card and node so we can read the config rom and we
 916                  * need to do device_initialize() now so
 917                  * device_for_each_child() in FW_NODE_UPDATED is
 918                  * doesn't freak out.
 919                  */
 920                 device_initialize(&device->device);
 921                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
 922                 device->card = fw_card_get(card);
 923                 device->node = fw_node_get(node);
 924                 device->node_id = node->node_id;
 925                 device->generation = card->generation;
 926                 INIT_LIST_HEAD(&device->client_list);
 927
 928                 /*
 929                  * Set the node data to point back to this device so
 930                  * FW_NODE_UPDATED callbacks can update the node_id
 931                  * and generation for the device.
 932                  */
 933                 node->data = device;
 934
 935                 /*
 936                  * Many devices are slow to respond after bus resets,
 937                  * especially if they are bus powered and go through
 938                  * power-up after getting plugged in.  We schedule the
 939                  * first config rom scan half a second after bus reset.
 940                  */
 941                 INIT_DELAYED_WORK(&device->work, fw_device_init);
 942                 schedule_delayed_work(&device->work, INITIAL_DELAY);
 943                 break;
 944
 945         case FW_NODE_INITIATED_RESET:
 946                 device = node->data;
 947                 if (device == NULL)
 948                         goto create;
 949
 950                 device->node_id = node->node_id;
 951                 smp_wmb();  /* update node_id before generation */
 952                 device->generation = card->generation;
 953                 if (atomic_cmpxchg(&device->state,
 954                             FW_DEVICE_RUNNING,
 955                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
 956                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
 957                         schedule_delayed_work(&device->work,
 958                                 node == card->local_node ? 0 : INITIAL_DELAY);
 959                 }
 960                 break;
 961
 962         case FW_NODE_UPDATED:
 963                 if (!node->link_on || node->data == NULL)
 964                         break;
 965
 966                 device = node->data;
 967                 device->node_id = node->node_id;
 968                 smp_wmb();  /* update node_id before generation */
 969                 device->generation = card->generation;
 970                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
 971                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
 972                         schedule_delayed_work(&device->work, 0);
 973                 }
 974                 break;
 975
 976         case FW_NODE_DESTROYED:
 977         case FW_NODE_LINK_OFF:
 978                 if (!node->data)
 979                         break;
 980
 981                 /*
 982                  * Destroy the device associated with the node.  There
 983                  * are two cases here: either the device is fully
 984                  * initialized (FW_DEVICE_RUNNING) or we're in the
 985                  * process of reading its config rom
 986                  * (FW_DEVICE_INITIALIZING).  If it is fully
 987                  * initialized we can reuse device->work to schedule a
 988                  * full fw_device_shutdown().  If not, there's work
 989                  * scheduled to read it's config rom, and we just put
 990                  * the device in shutdown state to have that code fail
 991                  * to create the device.
 992                  */
 993                 device = node->data;
 994                 if (atomic_xchg(&device->state,
 995                                 FW_DEVICE_SHUTDOWN) == FW_DEVICE_RUNNING) {
 996                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
 997                         schedule_delayed_work(&device->work, 0);
 998                 }
 999                 break;
1000         }
1001 }