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 fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 138 {
 139         struct fw_unit *unit = fw_unit(dev);
 140         char modalias[64];
 141
 142         get_modalias(unit, modalias, sizeof(modalias));
 143
 144         if (add_uevent_var(env, "MODALIAS=%s", modalias))
 145                 return -ENOMEM;
 146
 147         return 0;
 148 }
 149
 150 struct bus_type fw_bus_type = {
 151         .name = "firewire",
 152         .match = fw_unit_match,
 153 };
 154 EXPORT_SYMBOL(fw_bus_type);
 155
 156 static void fw_device_release(struct device *dev)
 157 {
 158         struct fw_device *device = fw_device(dev);
 159         struct fw_card *card = device->card;
 160         unsigned long flags;
 161
 162         /*
 163          * Take the card lock so we don't set this to NULL while a
 164          * FW_NODE_UPDATED callback is being handled or while the
 165          * bus manager work looks at this node.
 166          */
 167         spin_lock_irqsave(&card->lock, flags);
 168         device->node->data = NULL;
 169         spin_unlock_irqrestore(&card->lock, flags);
 170
 171         fw_node_put(device->node);
 172         kfree(device->config_rom);
 173         kfree(device);
 174         fw_card_put(card);
 175 }
 176
 177 int fw_device_enable_phys_dma(struct fw_device *device)
 178 {
 179         int generation = device->generation;
 180
 181         /* device->node_id, accessed below, must not be older than generation */
 182         smp_rmb();
 183
 184         return device->card->driver->enable_phys_dma(device->card,
 185                                                      device->node_id,
 186                                                      generation);
 187 }
 188 EXPORT_SYMBOL(fw_device_enable_phys_dma);
 189
 190 struct config_rom_attribute {
 191         struct device_attribute attr;
 192         u32 key;
 193 };
 194
 195 static ssize_t show_immediate(struct device *dev,
 196                               struct device_attribute *dattr, char *buf)
 197 {
 198         struct config_rom_attribute *attr =
 199                 container_of(dattr, struct config_rom_attribute, attr);
 200         struct fw_csr_iterator ci;
 201         u32 *dir;
 202         int key, value, ret = -ENOENT;
 203
 204         down_read(&fw_device_rwsem);
 205
 206         if (is_fw_unit(dev))
 207                 dir = fw_unit(dev)->directory;
 208         else
 209                 dir = fw_device(dev)->config_rom + 5;
 210
 211         fw_csr_iterator_init(&ci, dir);
 212         while (fw_csr_iterator_next(&ci, &key, &value))
 213                 if (attr->key == key) {
 214                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
 215                                        "0x%06x\n", value);
 216                         break;
 217                 }
 218
 219         up_read(&fw_device_rwsem);
 220
 221         return ret;
 222 }
 223
 224 #define IMMEDIATE_ATTR(name, key)                               \
 225         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
 226
 227 static ssize_t show_text_leaf(struct device *dev,
 228                               struct device_attribute *dattr, char *buf)
 229 {
 230         struct config_rom_attribute *attr =
 231                 container_of(dattr, struct config_rom_attribute, attr);
 232         struct fw_csr_iterator ci;
 233         u32 *dir, *block = NULL, *p, *end;
 234         int length, key, value, last_key = 0, ret = -ENOENT;
 235         char *b;
 236
 237         down_read(&fw_device_rwsem);
 238
 239         if (is_fw_unit(dev))
 240                 dir = fw_unit(dev)->directory;
 241         else
 242                 dir = fw_device(dev)->config_rom + 5;
 243
 244         fw_csr_iterator_init(&ci, dir);
 245         while (fw_csr_iterator_next(&ci, &key, &value)) {
 246                 if (attr->key == last_key &&
 247                     key == (CSR_DESCRIPTOR | CSR_LEAF))
 248                         block = ci.p - 1 + value;
 249                 last_key = key;
 250         }
 251
 252         if (block == NULL)
 253                 goto out;
 254
 255         length = min(block[0] >> 16, 256U);
 256         if (length < 3)
 257                 goto out;
 258
 259         if (block[1] != 0 || block[2] != 0)
 260                 /* Unknown encoding. */
 261                 goto out;
 262
 263         if (buf == NULL) {
 264                 ret = length * 4;
 265                 goto out;
 266         }
 267
 268         b = buf;
 269         end = &block[length + 1];
 270         for (p = &block[3]; p < end; p++, b += 4)
 271                 * (u32 *) b = (__force u32) __cpu_to_be32(*p);
 272
 273         /* Strip trailing whitespace and add newline. */
 274         while (b--, (isspace(*b) || *b == '\0') && b > buf);
 275         strcpy(b + 1, "\n");
 276         ret = b + 2 - buf;
 277  out:
 278         up_read(&fw_device_rwsem);
 279
 280         return ret;
 281 }
 282
 283 #define TEXT_LEAF_ATTR(name, key)                               \
 284         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
 285
 286 static struct config_rom_attribute config_rom_attributes[] = {
 287         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
 288         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
 289         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
 290         IMMEDIATE_ATTR(version, CSR_VERSION),
 291         IMMEDIATE_ATTR(model, CSR_MODEL),
 292         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
 293         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
 294         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
 295 };
 296
 297 static void init_fw_attribute_group(struct device *dev,
 298                                     struct device_attribute *attrs,
 299                                     struct fw_attribute_group *group)
 300 {
 301         struct device_attribute *attr;
 302         int i, j;
 303
 304         for (j = 0; attrs[j].attr.name != NULL; j++)
 305                 group->attrs[j] = &attrs[j].attr;
 306
 307         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
 308                 attr = &config_rom_attributes[i].attr;
 309                 if (attr->show(dev, attr, NULL) < 0)
 310                         continue;
 311                 group->attrs[j++] = &attr->attr;
 312         }
 313
 314         BUG_ON(j >= ARRAY_SIZE(group->attrs));
 315         group->attrs[j++] = NULL;
 316         group->groups[0] = &group->group;
 317         group->groups[1] = NULL;
 318         group->group.attrs = group->attrs;
 319         dev->groups = group->groups;
 320 }
 321
 322 static ssize_t modalias_show(struct device *dev,
 323                              struct device_attribute *attr, char *buf)
 324 {
 325         struct fw_unit *unit = fw_unit(dev);
 326         int length;
 327
 328         length = get_modalias(unit, buf, PAGE_SIZE);
 329         strcpy(buf + length, "\n");
 330
 331         return length + 1;
 332 }
 333
 334 static ssize_t 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 config_rom_show(struct device *dev,
 351                                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 guid_show(struct device *dev,
 365                          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 read_rom(struct fw_device *device,
 385                     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 /*
 637  * These defines control the retry behavior for reading the config
 638  * rom.  It shouldn't be necessary to tweak these; if the device
 639  * doesn't respond to a config rom read within 10 seconds, it's not
 640  * going to respond at all.  As for the initial delay, a lot of
 641  * devices will be able to respond within half a second after bus
 642  * reset.  On the other hand, it's not really worth being more
 643  * aggressive than that, since it scales pretty well; if 10 devices
 644  * are plugged in, they're all getting read within one second.
 645  */
 646
 647 #define MAX_RETRIES     10
 648 #define RETRY_DELAY     (3 * HZ)
 649 #define INITIAL_DELAY   (HZ / 2)
 650 #define SHUTDOWN_DELAY  (2 * HZ)
 651
 652 static void fw_device_shutdown(struct work_struct *work)
 653 {
 654         struct fw_device *device =
 655                 container_of(work, struct fw_device, work.work);
 656         int minor = MINOR(device->device.devt);
 657
 658         if (time_is_after_jiffies(device->card->reset_jiffies + SHUTDOWN_DELAY)
 659             && !list_empty(&device->card->link)) {
 660                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 661                 return;
 662         }
 663
 664         if (atomic_cmpxchg(&device->state,
 665                            FW_DEVICE_GONE,
 666                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
 667                 return;
 668
 669         fw_device_cdev_remove(device);
 670         device_for_each_child(&device->device, NULL, shutdown_unit);
 671         device_unregister(&device->device);
 672
 673         down_write(&fw_device_rwsem);
 674         idr_remove(&fw_device_idr, minor);
 675         up_write(&fw_device_rwsem);
 676
 677         fw_device_put(device);
 678 }
 679
 680 static struct device_type fw_device_type = {
 681         .release        = fw_device_release,
 682 };
 683
 684 static void fw_device_update(struct work_struct *work);
 685
 686 /*
 687  * If a device was pending for deletion because its node went away but its
 688  * bus info block and root directory header matches that of a newly discovered
 689  * device, revive the existing fw_device.
 690  * The newly allocated fw_device becomes obsolete instead.
 691  */
 692 static int lookup_existing_device(struct device *dev, void *data)
 693 {
 694         struct fw_device *old = fw_device(dev);
 695         struct fw_device *new = data;
 696         struct fw_card *card = new->card;
 697         int match = 0;
 698
 699         down_read(&fw_device_rwsem); /* serialize config_rom access */
 700         spin_lock_irq(&card->lock);  /* serialize node access */
 701
 702         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
 703             atomic_cmpxchg(&old->state,
 704                            FW_DEVICE_GONE,
 705                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 706                 struct fw_node *current_node = new->node;
 707                 struct fw_node *obsolete_node = old->node;
 708
 709                 new->node = obsolete_node;
 710                 new->node->data = new;
 711                 old->node = current_node;
 712                 old->node->data = old;
 713
 714                 old->max_speed = new->max_speed;
 715                 old->node_id = current_node->node_id;
 716                 smp_wmb();  /* update node_id before generation */
 717                 old->generation = card->generation;
 718                 old->config_rom_retries = 0;
 719                 fw_notify("rediscovered device %s\n", dev_name(dev));
 720
 721                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
 722                 schedule_delayed_work(&old->work, 0);
 723
 724                 if (current_node == card->root_node)
 725                         fw_schedule_bm_work(card, 0);
 726
 727                 match = 1;
 728         }
 729
 730         spin_unlock_irq(&card->lock);
 731         up_read(&fw_device_rwsem);
 732
 733         return match;
 734 }
 735
 736 static void fw_device_init(struct work_struct *work)
 737 {
 738         struct fw_device *device =
 739                 container_of(work, struct fw_device, work.work);
 740         struct device *revived_dev;
 741         int minor, err;
 742
 743         /*
 744          * All failure paths here set node->data to NULL, so that we
 745          * don't try to do device_for_each_child() on a kfree()'d
 746          * device.
 747          */
 748
 749         if (read_bus_info_block(device, device->generation) < 0) {
 750                 if (device->config_rom_retries < MAX_RETRIES &&
 751                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 752                         device->config_rom_retries++;
 753                         schedule_delayed_work(&device->work, RETRY_DELAY);
 754                 } else {
 755                         fw_notify("giving up on config rom for node id %x\n",
 756                                   device->node_id);
 757                         if (device->node == device->card->root_node)
 758                                 fw_schedule_bm_work(device->card, 0);
 759                         fw_device_release(&device->device);
 760                 }
 761                 return;
 762         }
 763
 764         revived_dev = device_find_child(device->card->device,
 765                                         device, lookup_existing_device);
 766         if (revived_dev) {
 767                 put_device(revived_dev);
 768                 fw_device_release(&device->device);
 769
 770                 return;
 771         }
 772
 773         device_initialize(&device->device);
 774
 775         fw_device_get(device);
 776         down_write(&fw_device_rwsem);
 777         err = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
 778               idr_get_new(&fw_device_idr, device, &minor) :
 779               -ENOMEM;
 780         up_write(&fw_device_rwsem);
 781
 782         if (err < 0)
 783                 goto error;
 784
 785         device->device.bus = &fw_bus_type;
 786         device->device.type = &fw_device_type;
 787         device->device.parent = device->card->device;
 788         device->device.devt = MKDEV(fw_cdev_major, minor);
 789         dev_set_name(&device->device, "fw%d", minor);
 790
 791         init_fw_attribute_group(&device->device,
 792                                 fw_device_attributes,
 793                                 &device->attribute_group);
 794         if (device_add(&device->device)) {
 795                 fw_error("Failed to add device.\n");
 796                 goto error_with_cdev;
 797         }
 798
 799         create_units(device);
 800
 801         /*
 802          * Transition the device to running state.  If it got pulled
 803          * out from under us while we did the intialization work, we
 804          * have to shut down the device again here.  Normally, though,
 805          * fw_node_event will be responsible for shutting it down when
 806          * necessary.  We have to use the atomic cmpxchg here to avoid
 807          * racing with the FW_NODE_DESTROYED case in
 808          * fw_node_event().
 809          */
 810         if (atomic_cmpxchg(&device->state,
 811                            FW_DEVICE_INITIALIZING,
 812                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 813                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
 814                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 815         } else {
 816                 if (device->config_rom_retries)
 817                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
 818                                   "%d config ROM retries\n",
 819                                   dev_name(&device->device),
 820                                   device->config_rom[3], device->config_rom[4],
 821                                   1 << device->max_speed,
 822                                   device->config_rom_retries);
 823                 else
 824                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
 825                                   dev_name(&device->device),
 826                                   device->config_rom[3], device->config_rom[4],
 827                                   1 << device->max_speed);
 828                 device->config_rom_retries = 0;
 829         }
 830
 831         /*
 832          * Reschedule the IRM work if we just finished reading the
 833          * root node config rom.  If this races with a bus reset we
 834          * just end up running the IRM work a couple of extra times -
 835          * pretty harmless.
 836          */
 837         if (device->node == device->card->root_node)
 838                 fw_schedule_bm_work(device->card, 0);
 839
 840         return;
 841
 842  error_with_cdev:
 843         down_write(&fw_device_rwsem);
 844         idr_remove(&fw_device_idr, minor);
 845         up_write(&fw_device_rwsem);
 846  error:
 847         fw_device_put(device);          /* fw_device_idr's reference */
 848
 849         put_device(&device->device);    /* our reference */
 850 }
 851
 852 static int update_unit(struct device *dev, void *data)
 853 {
 854         struct fw_unit *unit = fw_unit(dev);
 855         struct fw_driver *driver = (struct fw_driver *)dev->driver;
 856
 857         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
 858                 down(&dev->sem);
 859                 driver->update(unit);
 860                 up(&dev->sem);
 861         }
 862
 863         return 0;
 864 }
 865
 866 static void fw_device_update(struct work_struct *work)
 867 {
 868         struct fw_device *device =
 869                 container_of(work, struct fw_device, work.work);
 870
 871         fw_device_cdev_update(device);
 872         device_for_each_child(&device->device, NULL, update_unit);
 873 }
 874
 875 enum {
 876         REREAD_BIB_ERROR,
 877         REREAD_BIB_GONE,
 878         REREAD_BIB_UNCHANGED,
 879         REREAD_BIB_CHANGED,
 880 };
 881
 882 /* Reread and compare bus info block and header of root directory */
 883 static int reread_bus_info_block(struct fw_device *device, int generation)
 884 {
 885         u32 q;
 886         int i;
 887
 888         for (i = 0; i < 6; i++) {
 889                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
 890                         return REREAD_BIB_ERROR;
 891
 892                 if (i == 0 && q == 0)
 893                         return REREAD_BIB_GONE;
 894
 895                 if (i > device->config_rom_length || q != device->config_rom[i])
 896                         return REREAD_BIB_CHANGED;
 897         }
 898
 899         return REREAD_BIB_UNCHANGED;
 900 }
 901
 902 static void fw_device_refresh(struct work_struct *work)
 903 {
 904         struct fw_device *device =
 905                 container_of(work, struct fw_device, work.work);
 906         struct fw_card *card = device->card;
 907         int node_id = device->node_id;
 908
 909         switch (reread_bus_info_block(device, device->generation)) {
 910         case REREAD_BIB_ERROR:
 911                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
 912                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 913                         device->config_rom_retries++;
 914                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
 915
 916                         return;
 917                 }
 918                 goto give_up;
 919
 920         case REREAD_BIB_GONE:
 921                 goto gone;
 922
 923         case REREAD_BIB_UNCHANGED:
 924                 if (atomic_cmpxchg(&device->state,
 925                                    FW_DEVICE_INITIALIZING,
 926                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
 927                         goto gone;
 928
 929                 fw_device_update(work);
 930                 device->config_rom_retries = 0;
 931                 goto out;
 932
 933         case REREAD_BIB_CHANGED:
 934                 break;
 935         }
 936
 937         /*
 938          * Something changed.  We keep things simple and don't investigate
 939          * further.  We just destroy all previous units and create new ones.
 940          */
 941         device_for_each_child(&device->device, NULL, shutdown_unit);
 942
 943         if (read_bus_info_block(device, device->generation) < 0) {
 944                 if (device->config_rom_retries < MAX_RETRIES &&
 945                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 946                         device->config_rom_retries++;
 947                         schedule_delayed_work(&device->work, RETRY_DELAY);
 948
 949                         return;
 950                 }
 951                 goto give_up;
 952         }
 953
 954         create_units(device);
 955
 956         if (atomic_cmpxchg(&device->state,
 957                            FW_DEVICE_INITIALIZING,
 958                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
 959                 goto gone;
 960
 961         fw_notify("refreshed device %s\n", dev_name(&device->device));
 962         device->config_rom_retries = 0;
 963         goto out;
 964
 965  give_up:
 966         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
 967  gone:
 968         atomic_set(&device->state, FW_DEVICE_GONE);
 969         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
 970         schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 971  out:
 972         if (node_id == card->root_node->node_id)
 973                 fw_schedule_bm_work(card, 0);
 974 }
 975
 976 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
 977 {
 978         struct fw_device *device;
 979
 980         switch (event) {
 981         case FW_NODE_CREATED:
 982         case FW_NODE_LINK_ON:
 983                 if (!node->link_on)
 984                         break;
 985  create:
 986                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
 987                 if (device == NULL)
 988                         break;
 989
 990                 /*
 991                  * Do minimal intialization of the device here, the
 992                  * rest will happen in fw_device_init().
 993                  *
 994                  * Attention:  A lot of things, even fw_device_get(),
 995                  * cannot be done before fw_device_init() finished!
 996                  * You can basically just check device->state and
 997                  * schedule work until then, but only while holding
 998                  * card->lock.
 999                  */
1000                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1001                 device->card = fw_card_get(card);
1002                 device->node = fw_node_get(node);
1003                 device->node_id = node->node_id;
1004                 device->generation = card->generation;
1005                 mutex_init(&device->client_list_mutex);
1006                 INIT_LIST_HEAD(&device->client_list);
1007
1008                 /*
1009                  * Set the node data to point back to this device so
1010                  * FW_NODE_UPDATED callbacks can update the node_id
1011                  * and generation for the device.
1012                  */
1013                 node->data = device;
1014
1015                 /*
1016                  * Many devices are slow to respond after bus resets,
1017                  * especially if they are bus powered and go through
1018                  * power-up after getting plugged in.  We schedule the
1019                  * first config rom scan half a second after bus reset.
1020                  */
1021                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1022                 schedule_delayed_work(&device->work, INITIAL_DELAY);
1023                 break;
1024
1025         case FW_NODE_INITIATED_RESET:
1026                 device = node->data;
1027                 if (device == NULL)
1028                         goto create;
1029
1030                 device->node_id = node->node_id;
1031                 smp_wmb();  /* update node_id before generation */
1032                 device->generation = card->generation;
1033                 if (atomic_cmpxchg(&device->state,
1034                             FW_DEVICE_RUNNING,
1035                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1036                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1037                         schedule_delayed_work(&device->work,
1038                                 node == card->local_node ? 0 : INITIAL_DELAY);
1039                 }
1040                 break;
1041
1042         case FW_NODE_UPDATED:
1043                 if (!node->link_on || node->data == NULL)
1044                         break;
1045
1046                 device = node->data;
1047                 device->node_id = node->node_id;
1048                 smp_wmb();  /* update node_id before generation */
1049                 device->generation = card->generation;
1050                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1051                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1052                         schedule_delayed_work(&device->work, 0);
1053                 }
1054                 break;
1055
1056         case FW_NODE_DESTROYED:
1057         case FW_NODE_LINK_OFF:
1058                 if (!node->data)
1059                         break;
1060
1061                 /*
1062                  * Destroy the device associated with the node.  There
1063                  * are two cases here: either the device is fully
1064                  * initialized (FW_DEVICE_RUNNING) or we're in the
1065                  * process of reading its config rom
1066                  * (FW_DEVICE_INITIALIZING).  If it is fully
1067                  * initialized we can reuse device->work to schedule a
1068                  * full fw_device_shutdown().  If not, there's work
1069                  * scheduled to read it's config rom, and we just put
1070                  * the device in shutdown state to have that code fail
1071                  * to create the device.
1072                  */
1073                 device = node->data;
1074                 if (atomic_xchg(&device->state,
1075                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1076                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1077                         schedule_delayed_work(&device->work,
1078                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1079                 }
1080                 break;
1081         }
1082 }