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