Pileus Git - ~andy/linux/blob - drivers/firewire/core-device.c

   1 /*
   2  * Device probing and sysfs code.
   3  *
   4  * Copyright (C) 2005-2006  Kristian Hoegsberg <krh@bitplanet.net>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 #include <linux/ctype.h>
  22 #include <linux/delay.h>
  23 #include <linux/device.h>
  24 #include <linux/errno.h>
  25 #include <linux/firewire.h>
  26 #include <linux/firewire-constants.h>
  27 #include <linux/idr.h>
  28 #include <linux/jiffies.h>
  29 #include <linux/kobject.h>
  30 #include <linux/list.h>
  31 #include <linux/mod_devicetable.h>
  32 #include <linux/module.h>
  33 #include <linux/mutex.h>
  34 #include <linux/rwsem.h>
  35 #include <linux/semaphore.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/string.h>
  38 #include <linux/workqueue.h>
  39
  40 #include <asm/atomic.h>
  41 #include <asm/byteorder.h>
  42 #include <asm/system.h>
  43
  44 #include "core.h"
  45
  46 void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
  47 {
  48         ci->p = p + 1;
  49         ci->end = ci->p + (p[0] >> 16);
  50 }
  51 EXPORT_SYMBOL(fw_csr_iterator_init);
  52
  53 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
  54 {
  55         *key = *ci->p >> 24;
  56         *value = *ci->p & 0xffffff;
  57
  58         return ci->p++ < ci->end;
  59 }
  60 EXPORT_SYMBOL(fw_csr_iterator_next);
  61
  62 static int is_fw_unit(struct device *dev);
  63
  64 static int match_unit_directory(u32 *directory, u32 match_flags,
  65                                 const struct ieee1394_device_id *id)
  66 {
  67         struct fw_csr_iterator ci;
  68         int key, value, match;
  69
  70         match = 0;
  71         fw_csr_iterator_init(&ci, directory);
  72         while (fw_csr_iterator_next(&ci, &key, &value)) {
  73                 if (key == CSR_VENDOR && value == id->vendor_id)
  74                         match |= IEEE1394_MATCH_VENDOR_ID;
  75                 if (key == CSR_MODEL && value == id->model_id)
  76                         match |= IEEE1394_MATCH_MODEL_ID;
  77                 if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
  78                         match |= IEEE1394_MATCH_SPECIFIER_ID;
  79                 if (key == CSR_VERSION && value == id->version)
  80                         match |= IEEE1394_MATCH_VERSION;
  81         }
  82
  83         return (match & match_flags) == match_flags;
  84 }
  85
  86 static int fw_unit_match(struct device *dev, struct device_driver *drv)
  87 {
  88         struct fw_unit *unit = fw_unit(dev);
  89         struct fw_device *device;
  90         const struct ieee1394_device_id *id;
  91
  92         /* We only allow binding to fw_units. */
  93         if (!is_fw_unit(dev))
  94                 return 0;
  95
  96         device = fw_device(unit->device.parent);
  97         id = container_of(drv, struct fw_driver, driver)->id_table;
  98
  99         for (; id->match_flags != 0; id++) {
 100                 if (match_unit_directory(unit->directory, id->match_flags, id))
 101                         return 1;
 102
 103                 /* Also check vendor ID in the root directory. */
 104                 if ((id->match_flags & IEEE1394_MATCH_VENDOR_ID) &&
 105                     match_unit_directory(&device->config_rom[5],
 106                                 IEEE1394_MATCH_VENDOR_ID, id) &&
 107                     match_unit_directory(unit->directory, id->match_flags
 108                                 & ~IEEE1394_MATCH_VENDOR_ID, id))
 109                         return 1;
 110         }
 111
 112         return 0;
 113 }
 114
 115 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
 116 {
 117         struct fw_device *device = fw_device(unit->device.parent);
 118         struct fw_csr_iterator ci;
 119
 120         int key, value;
 121         int vendor = 0;
 122         int model = 0;
 123         int specifier_id = 0;
 124         int version = 0;
 125
 126         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 127         while (fw_csr_iterator_next(&ci, &key, &value)) {
 128                 switch (key) {
 129                 case CSR_VENDOR:
 130                         vendor = value;
 131                         break;
 132                 case CSR_MODEL:
 133                         model = value;
 134                         break;
 135                 }
 136         }
 137
 138         fw_csr_iterator_init(&ci, unit->directory);
 139         while (fw_csr_iterator_next(&ci, &key, &value)) {
 140                 switch (key) {
 141                 case CSR_SPECIFIER_ID:
 142                         specifier_id = value;
 143                         break;
 144                 case CSR_VERSION:
 145                         version = value;
 146                         break;
 147                 }
 148         }
 149
 150         return snprintf(buffer, buffer_size,
 151                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
 152                         vendor, model, specifier_id, version);
 153 }
 154
 155 static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 156 {
 157         struct fw_unit *unit = fw_unit(dev);
 158         char modalias[64];
 159
 160         get_modalias(unit, modalias, sizeof(modalias));
 161
 162         if (add_uevent_var(env, "MODALIAS=%s", modalias))
 163                 return -ENOMEM;
 164
 165         return 0;
 166 }
 167
 168 struct bus_type fw_bus_type = {
 169         .name = "firewire",
 170         .match = fw_unit_match,
 171 };
 172 EXPORT_SYMBOL(fw_bus_type);
 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 show_immediate(struct device *dev,
 193                               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 show_text_leaf(struct device *dev,
 225                               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 init_fw_attribute_group(struct device *dev,
 295                                     struct device_attribute *attrs,
 296                                     struct fw_attribute_group *group)
 297 {
 298         struct device_attribute *attr;
 299         int i, j;
 300
 301         for (j = 0; attrs[j].attr.name != NULL; j++)
 302                 group->attrs[j] = &attrs[j].attr;
 303
 304         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
 305                 attr = &config_rom_attributes[i].attr;
 306                 if (attr->show(dev, attr, NULL) < 0)
 307                         continue;
 308                 group->attrs[j++] = &attr->attr;
 309         }
 310
 311         group->attrs[j] = NULL;
 312         group->groups[0] = &group->group;
 313         group->groups[1] = NULL;
 314         group->group.attrs = group->attrs;
 315         dev->groups = group->groups;
 316 }
 317
 318 static ssize_t modalias_show(struct device *dev,
 319                              struct device_attribute *attr, char *buf)
 320 {
 321         struct fw_unit *unit = fw_unit(dev);
 322         int length;
 323
 324         length = get_modalias(unit, buf, PAGE_SIZE);
 325         strcpy(buf + length, "\n");
 326
 327         return length + 1;
 328 }
 329
 330 static ssize_t rom_index_show(struct device *dev,
 331                               struct device_attribute *attr, char *buf)
 332 {
 333         struct fw_device *device = fw_device(dev->parent);
 334         struct fw_unit *unit = fw_unit(dev);
 335
 336         return snprintf(buf, PAGE_SIZE, "%d\n",
 337                         (int)(unit->directory - device->config_rom));
 338 }
 339
 340 static struct device_attribute fw_unit_attributes[] = {
 341         __ATTR_RO(modalias),
 342         __ATTR_RO(rom_index),
 343         __ATTR_NULL,
 344 };
 345
 346 static ssize_t config_rom_show(struct device *dev,
 347                                struct device_attribute *attr, char *buf)
 348 {
 349         struct fw_device *device = fw_device(dev);
 350         size_t length;
 351
 352         down_read(&fw_device_rwsem);
 353         length = device->config_rom_length * 4;
 354         memcpy(buf, device->config_rom, length);
 355         up_read(&fw_device_rwsem);
 356
 357         return length;
 358 }
 359
 360 static ssize_t guid_show(struct device *dev,
 361                          struct device_attribute *attr, char *buf)
 362 {
 363         struct fw_device *device = fw_device(dev);
 364         int ret;
 365
 366         down_read(&fw_device_rwsem);
 367         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
 368                        device->config_rom[3], device->config_rom[4]);
 369         up_read(&fw_device_rwsem);
 370
 371         return ret;
 372 }
 373
 374 static int units_sprintf(char *buf, u32 *directory)
 375 {
 376         struct fw_csr_iterator ci;
 377         int key, value;
 378         int specifier_id = 0;
 379         int version = 0;
 380
 381         fw_csr_iterator_init(&ci, directory);
 382         while (fw_csr_iterator_next(&ci, &key, &value)) {
 383                 switch (key) {
 384                 case CSR_SPECIFIER_ID:
 385                         specifier_id = value;
 386                         break;
 387                 case CSR_VERSION:
 388                         version = value;
 389                         break;
 390                 }
 391         }
 392
 393         return sprintf(buf, "0x%06x:0x%06x ", specifier_id, version);
 394 }
 395
 396 static ssize_t units_show(struct device *dev,
 397                           struct device_attribute *attr, char *buf)
 398 {
 399         struct fw_device *device = fw_device(dev);
 400         struct fw_csr_iterator ci;
 401         int key, value, i = 0;
 402
 403         down_read(&fw_device_rwsem);
 404         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 405         while (fw_csr_iterator_next(&ci, &key, &value)) {
 406                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 407                         continue;
 408                 i += units_sprintf(&buf[i], ci.p + value - 1);
 409                 if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
 410                         break;
 411         }
 412         up_read(&fw_device_rwsem);
 413
 414         if (i)
 415                 buf[i - 1] = '\n';
 416
 417         return i;
 418 }
 419
 420 static struct device_attribute fw_device_attributes[] = {
 421         __ATTR_RO(config_rom),
 422         __ATTR_RO(guid),
 423         __ATTR_RO(units),
 424         __ATTR_NULL,
 425 };
 426
 427 static int read_rom(struct fw_device *device,
 428                     int generation, int index, u32 *data)
 429 {
 430         int rcode;
 431
 432         /* device->node_id, accessed below, must not be older than generation */
 433         smp_rmb();
 434
 435         rcode = fw_run_transaction(device->card, TCODE_READ_QUADLET_REQUEST,
 436                         device->node_id, generation, device->max_speed,
 437                         (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4,
 438                         data, 4);
 439         be32_to_cpus(data);
 440
 441         return rcode;
 442 }
 443
 444 #define READ_BIB_ROM_SIZE       256
 445 #define READ_BIB_STACK_SIZE     16
 446
 447 /*
 448  * Read the bus info block, perform a speed probe, and read all of the rest of
 449  * the config ROM.  We do all this with a cached bus generation.  If the bus
 450  * generation changes under us, read_bus_info_block will fail and get retried.
 451  * It's better to start all over in this case because the node from which we
 452  * are reading the ROM may have changed the ROM during the reset.
 453  */
 454 static int read_bus_info_block(struct fw_device *device, int generation)
 455 {
 456         u32 *rom, *stack, *old_rom, *new_rom;
 457         u32 sp, key;
 458         int i, end, length, ret = -1;
 459
 460         rom = kmalloc(sizeof(*rom) * READ_BIB_ROM_SIZE +
 461                       sizeof(*stack) * READ_BIB_STACK_SIZE, GFP_KERNEL);
 462         if (rom == NULL)
 463                 return -ENOMEM;
 464
 465         stack = &rom[READ_BIB_ROM_SIZE];
 466
 467         device->max_speed = SCODE_100;
 468
 469         /* First read the bus info block. */
 470         for (i = 0; i < 5; i++) {
 471                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 472                         goto out;
 473                 /*
 474                  * As per IEEE1212 7.2, during power-up, devices can
 475                  * reply with a 0 for the first quadlet of the config
 476                  * rom to indicate that they are booting (for example,
 477                  * if the firmware is on the disk of a external
 478                  * harddisk).  In that case we just fail, and the
 479                  * retry mechanism will try again later.
 480                  */
 481                 if (i == 0 && rom[i] == 0)
 482                         goto out;
 483         }
 484
 485         device->max_speed = device->node->max_speed;
 486
 487         /*
 488          * Determine the speed of
 489          *   - devices with link speed less than PHY speed,
 490          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
 491          *   - all devices if there are 1394b repeaters.
 492          * Note, we cannot use the bus info block's link_spd as starting point
 493          * because some buggy firmwares set it lower than necessary and because
 494          * 1394-1995 nodes do not have the field.
 495          */
 496         if ((rom[2] & 0x7) < device->max_speed ||
 497             device->max_speed == SCODE_BETA ||
 498             device->card->beta_repeaters_present) {
 499                 u32 dummy;
 500
 501                 /* for S1600 and S3200 */
 502                 if (device->max_speed == SCODE_BETA)
 503                         device->max_speed = device->card->link_speed;
 504
 505                 while (device->max_speed > SCODE_100) {
 506                         if (read_rom(device, generation, 0, &dummy) ==
 507                             RCODE_COMPLETE)
 508                                 break;
 509                         device->max_speed--;
 510                 }
 511         }
 512
 513         /*
 514          * Now parse the config rom.  The config rom is a recursive
 515          * directory structure so we parse it using a stack of
 516          * references to the blocks that make up the structure.  We
 517          * push a reference to the root directory on the stack to
 518          * start things off.
 519          */
 520         length = i;
 521         sp = 0;
 522         stack[sp++] = 0xc0000005;
 523         while (sp > 0) {
 524                 /*
 525                  * Pop the next block reference of the stack.  The
 526                  * lower 24 bits is the offset into the config rom,
 527                  * the upper 8 bits are the type of the reference the
 528                  * block.
 529                  */
 530                 key = stack[--sp];
 531                 i = key & 0xffffff;
 532                 if (i >= READ_BIB_ROM_SIZE)
 533                         /*
 534                          * The reference points outside the standard
 535                          * config rom area, something's fishy.
 536                          */
 537                         goto out;
 538
 539                 /* Read header quadlet for the block to get the length. */
 540                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 541                         goto out;
 542                 end = i + (rom[i] >> 16) + 1;
 543                 i++;
 544                 if (end > READ_BIB_ROM_SIZE)
 545                         /*
 546                          * This block extends outside standard config
 547                          * area (and the array we're reading it
 548                          * into).  That's broken, so ignore this
 549                          * device.
 550                          */
 551                         goto out;
 552
 553                 /*
 554                  * Now read in the block.  If this is a directory
 555                  * block, check the entries as we read them to see if
 556                  * it references another block, and push it in that case.
 557                  */
 558                 while (i < end) {
 559                         if (read_rom(device, generation, i, &rom[i]) !=
 560                             RCODE_COMPLETE)
 561                                 goto out;
 562                         if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
 563                             sp < READ_BIB_STACK_SIZE)
 564                                 stack[sp++] = i + rom[i];
 565                         i++;
 566                 }
 567                 if (length < i)
 568                         length = i;
 569         }
 570
 571         old_rom = device->config_rom;
 572         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
 573         if (new_rom == NULL)
 574                 goto out;
 575
 576         down_write(&fw_device_rwsem);
 577         device->config_rom = new_rom;
 578         device->config_rom_length = length;
 579         up_write(&fw_device_rwsem);
 580
 581         kfree(old_rom);
 582         ret = 0;
 583         device->cmc = rom[2] >> 30 & 1;
 584  out:
 585         kfree(rom);
 586
 587         return ret;
 588 }
 589
 590 static void fw_unit_release(struct device *dev)
 591 {
 592         struct fw_unit *unit = fw_unit(dev);
 593
 594         kfree(unit);
 595 }
 596
 597 static struct device_type fw_unit_type = {
 598         .uevent         = fw_unit_uevent,
 599         .release        = fw_unit_release,
 600 };
 601
 602 static int is_fw_unit(struct device *dev)
 603 {
 604         return dev->type == &fw_unit_type;
 605 }
 606
 607 static void create_units(struct fw_device *device)
 608 {
 609         struct fw_csr_iterator ci;
 610         struct fw_unit *unit;
 611         int key, value, i;
 612
 613         i = 0;
 614         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 615         while (fw_csr_iterator_next(&ci, &key, &value)) {
 616                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 617                         continue;
 618
 619                 /*
 620                  * Get the address of the unit directory and try to
 621                  * match the drivers id_tables against it.
 622                  */
 623                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 624                 if (unit == NULL) {
 625                         fw_error("failed to allocate memory for unit\n");
 626                         continue;
 627                 }
 628
 629                 unit->directory = ci.p + value - 1;
 630                 unit->device.bus = &fw_bus_type;
 631                 unit->device.type = &fw_unit_type;
 632                 unit->device.parent = &device->device;
 633                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
 634
 635                 BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
 636                                 ARRAY_SIZE(fw_unit_attributes) +
 637                                 ARRAY_SIZE(config_rom_attributes));
 638                 init_fw_attribute_group(&unit->device,
 639                                         fw_unit_attributes,
 640                                         &unit->attribute_group);
 641
 642                 if (device_register(&unit->device) < 0)
 643                         goto skip_unit;
 644
 645                 continue;
 646
 647         skip_unit:
 648                 kfree(unit);
 649         }
 650 }
 651
 652 static int shutdown_unit(struct device *device, void *data)
 653 {
 654         device_unregister(device);
 655
 656         return 0;
 657 }
 658
 659 /*
 660  * fw_device_rwsem acts as dual purpose mutex:
 661  *   - serializes accesses to fw_device_idr,
 662  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 663  *     fw_unit.directory, unless those accesses happen at safe occasions
 664  */
 665 DECLARE_RWSEM(fw_device_rwsem);
 666
 667 DEFINE_IDR(fw_device_idr);
 668 int fw_cdev_major;
 669
 670 struct fw_device *fw_device_get_by_devt(dev_t devt)
 671 {
 672         struct fw_device *device;
 673
 674         down_read(&fw_device_rwsem);
 675         device = idr_find(&fw_device_idr, MINOR(devt));
 676         if (device)
 677                 fw_device_get(device);
 678         up_read(&fw_device_rwsem);
 679
 680         return device;
 681 }
 682
 683 /*
 684  * These defines control the retry behavior for reading the config
 685  * rom.  It shouldn't be necessary to tweak these; if the device
 686  * doesn't respond to a config rom read within 10 seconds, it's not
 687  * going to respond at all.  As for the initial delay, a lot of
 688  * devices will be able to respond within half a second after bus
 689  * reset.  On the other hand, it's not really worth being more
 690  * aggressive than that, since it scales pretty well; if 10 devices
 691  * are plugged in, they're all getting read within one second.
 692  */
 693
 694 #define MAX_RETRIES     10
 695 #define RETRY_DELAY     (3 * HZ)
 696 #define INITIAL_DELAY   (HZ / 2)
 697 #define SHUTDOWN_DELAY  (2 * HZ)
 698
 699 static void fw_device_shutdown(struct work_struct *work)
 700 {
 701         struct fw_device *device =
 702                 container_of(work, struct fw_device, work.work);
 703         int minor = MINOR(device->device.devt);
 704
 705         if (time_is_after_jiffies(device->card->reset_jiffies + SHUTDOWN_DELAY)
 706             && !list_empty(&device->card->link)) {
 707                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 708                 return;
 709         }
 710
 711         if (atomic_cmpxchg(&device->state,
 712                            FW_DEVICE_GONE,
 713                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
 714                 return;
 715
 716         fw_device_cdev_remove(device);
 717         device_for_each_child(&device->device, NULL, shutdown_unit);
 718         device_unregister(&device->device);
 719
 720         down_write(&fw_device_rwsem);
 721         idr_remove(&fw_device_idr, minor);
 722         up_write(&fw_device_rwsem);
 723
 724         fw_device_put(device);
 725 }
 726
 727 static void fw_device_release(struct device *dev)
 728 {
 729         struct fw_device *device = fw_device(dev);
 730         struct fw_card *card = device->card;
 731         unsigned long flags;
 732
 733         /*
 734          * Take the card lock so we don't set this to NULL while a
 735          * FW_NODE_UPDATED callback is being handled or while the
 736          * bus manager work looks at this node.
 737          */
 738         spin_lock_irqsave(&card->lock, flags);
 739         device->node->data = NULL;
 740         spin_unlock_irqrestore(&card->lock, flags);
 741
 742         fw_node_put(device->node);
 743         kfree(device->config_rom);
 744         kfree(device);
 745         fw_card_put(card);
 746 }
 747
 748 static struct device_type fw_device_type = {
 749         .release = fw_device_release,
 750 };
 751
 752 static int update_unit(struct device *dev, void *data)
 753 {
 754         struct fw_unit *unit = fw_unit(dev);
 755         struct fw_driver *driver = (struct fw_driver *)dev->driver;
 756
 757         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
 758                 down(&dev->sem);
 759                 driver->update(unit);
 760                 up(&dev->sem);
 761         }
 762
 763         return 0;
 764 }
 765
 766 static void fw_device_update(struct work_struct *work)
 767 {
 768         struct fw_device *device =
 769                 container_of(work, struct fw_device, work.work);
 770
 771         fw_device_cdev_update(device);
 772         device_for_each_child(&device->device, NULL, update_unit);
 773 }
 774
 775 /*
 776  * If a device was pending for deletion because its node went away but its
 777  * bus info block and root directory header matches that of a newly discovered
 778  * device, revive the existing fw_device.
 779  * The newly allocated fw_device becomes obsolete instead.
 780  */
 781 static int lookup_existing_device(struct device *dev, void *data)
 782 {
 783         struct fw_device *old = fw_device(dev);
 784         struct fw_device *new = data;
 785         struct fw_card *card = new->card;
 786         int match = 0;
 787
 788         down_read(&fw_device_rwsem); /* serialize config_rom access */
 789         spin_lock_irq(&card->lock);  /* serialize node access */
 790
 791         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
 792             atomic_cmpxchg(&old->state,
 793                            FW_DEVICE_GONE,
 794                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 795                 struct fw_node *current_node = new->node;
 796                 struct fw_node *obsolete_node = old->node;
 797
 798                 new->node = obsolete_node;
 799                 new->node->data = new;
 800                 old->node = current_node;
 801                 old->node->data = old;
 802
 803                 old->max_speed = new->max_speed;
 804                 old->node_id = current_node->node_id;
 805                 smp_wmb();  /* update node_id before generation */
 806                 old->generation = card->generation;
 807                 old->config_rom_retries = 0;
 808                 fw_notify("rediscovered device %s\n", dev_name(dev));
 809
 810                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
 811                 schedule_delayed_work(&old->work, 0);
 812
 813                 if (current_node == card->root_node)
 814                         fw_schedule_bm_work(card, 0);
 815
 816                 match = 1;
 817         }
 818
 819         spin_unlock_irq(&card->lock);
 820         up_read(&fw_device_rwsem);
 821
 822         return match;
 823 }
 824
 825 enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
 826
 827 void fw_device_set_broadcast_channel(struct fw_device *device, int generation)
 828 {
 829         struct fw_card *card = device->card;
 830         __be32 data;
 831         int rcode;
 832
 833         if (!card->broadcast_channel_allocated)
 834                 return;
 835
 836         if (device->bc_implemented == BC_UNKNOWN) {
 837                 rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
 838                                 device->node_id, generation, device->max_speed,
 839                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 840                                 &data, 4);
 841                 switch (rcode) {
 842                 case RCODE_COMPLETE:
 843                         if (data & cpu_to_be32(1 << 31)) {
 844                                 device->bc_implemented = BC_IMPLEMENTED;
 845                                 break;
 846                         }
 847                         /* else fall through to case address error */
 848                 case RCODE_ADDRESS_ERROR:
 849                         device->bc_implemented = BC_UNIMPLEMENTED;
 850                 }
 851         }
 852
 853         if (device->bc_implemented == BC_IMPLEMENTED) {
 854                 data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
 855                                    BROADCAST_CHANNEL_VALID);
 856                 fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
 857                                 device->node_id, generation, device->max_speed,
 858                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 859                                 &data, 4);
 860         }
 861 }
 862
 863 static void fw_device_init(struct work_struct *work)
 864 {
 865         struct fw_device *device =
 866                 container_of(work, struct fw_device, work.work);
 867         struct device *revived_dev;
 868         int minor, ret;
 869
 870         /*
 871          * All failure paths here set node->data to NULL, so that we
 872          * don't try to do device_for_each_child() on a kfree()'d
 873          * device.
 874          */
 875
 876         if (read_bus_info_block(device, device->generation) < 0) {
 877                 if (device->config_rom_retries < MAX_RETRIES &&
 878                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 879                         device->config_rom_retries++;
 880                         schedule_delayed_work(&device->work, RETRY_DELAY);
 881                 } else {
 882                         fw_notify("giving up on config rom for node id %x\n",
 883                                   device->node_id);
 884                         if (device->node == device->card->root_node)
 885                                 fw_schedule_bm_work(device->card, 0);
 886                         fw_device_release(&device->device);
 887                 }
 888                 return;
 889         }
 890
 891         revived_dev = device_find_child(device->card->device,
 892                                         device, lookup_existing_device);
 893         if (revived_dev) {
 894                 put_device(revived_dev);
 895                 fw_device_release(&device->device);
 896
 897                 return;
 898         }
 899
 900         device_initialize(&device->device);
 901
 902         fw_device_get(device);
 903         down_write(&fw_device_rwsem);
 904         ret = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
 905               idr_get_new(&fw_device_idr, device, &minor) :
 906               -ENOMEM;
 907         up_write(&fw_device_rwsem);
 908
 909         if (ret < 0)
 910                 goto error;
 911
 912         device->device.bus = &fw_bus_type;
 913         device->device.type = &fw_device_type;
 914         device->device.parent = device->card->device;
 915         device->device.devt = MKDEV(fw_cdev_major, minor);
 916         dev_set_name(&device->device, "fw%d", minor);
 917
 918         BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
 919                         ARRAY_SIZE(fw_device_attributes) +
 920                         ARRAY_SIZE(config_rom_attributes));
 921         init_fw_attribute_group(&device->device,
 922                                 fw_device_attributes,
 923                                 &device->attribute_group);
 924
 925         if (device_add(&device->device)) {
 926                 fw_error("Failed to add device.\n");
 927                 goto error_with_cdev;
 928         }
 929
 930         create_units(device);
 931
 932         /*
 933          * Transition the device to running state.  If it got pulled
 934          * out from under us while we did the intialization work, we
 935          * have to shut down the device again here.  Normally, though,
 936          * fw_node_event will be responsible for shutting it down when
 937          * necessary.  We have to use the atomic cmpxchg here to avoid
 938          * racing with the FW_NODE_DESTROYED case in
 939          * fw_node_event().
 940          */
 941         if (atomic_cmpxchg(&device->state,
 942                            FW_DEVICE_INITIALIZING,
 943                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 944                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
 945                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 946         } else {
 947                 if (device->config_rom_retries)
 948                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
 949                                   "%d config ROM retries\n",
 950                                   dev_name(&device->device),
 951                                   device->config_rom[3], device->config_rom[4],
 952                                   1 << device->max_speed,
 953                                   device->config_rom_retries);
 954                 else
 955                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
 956                                   dev_name(&device->device),
 957                                   device->config_rom[3], device->config_rom[4],
 958                                   1 << device->max_speed);
 959                 device->config_rom_retries = 0;
 960
 961                 fw_device_set_broadcast_channel(device, device->generation);
 962         }
 963
 964         /*
 965          * Reschedule the IRM work if we just finished reading the
 966          * root node config rom.  If this races with a bus reset we
 967          * just end up running the IRM work a couple of extra times -
 968          * pretty harmless.
 969          */
 970         if (device->node == device->card->root_node)
 971                 fw_schedule_bm_work(device->card, 0);
 972
 973         return;
 974
 975  error_with_cdev:
 976         down_write(&fw_device_rwsem);
 977         idr_remove(&fw_device_idr, minor);
 978         up_write(&fw_device_rwsem);
 979  error:
 980         fw_device_put(device);          /* fw_device_idr's reference */
 981
 982         put_device(&device->device);    /* our reference */
 983 }
 984
 985 enum {
 986         REREAD_BIB_ERROR,
 987         REREAD_BIB_GONE,
 988         REREAD_BIB_UNCHANGED,
 989         REREAD_BIB_CHANGED,
 990 };
 991
 992 /* Reread and compare bus info block and header of root directory */
 993 static int reread_bus_info_block(struct fw_device *device, int generation)
 994 {
 995         u32 q;
 996         int i;
 997
 998         for (i = 0; i < 6; i++) {
 999                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
1000                         return REREAD_BIB_ERROR;
1001
1002                 if (i == 0 && q == 0)
1003                         return REREAD_BIB_GONE;
1004
1005                 if (q != device->config_rom[i])
1006                         return REREAD_BIB_CHANGED;
1007         }
1008
1009         return REREAD_BIB_UNCHANGED;
1010 }
1011
1012 static void fw_device_refresh(struct work_struct *work)
1013 {
1014         struct fw_device *device =
1015                 container_of(work, struct fw_device, work.work);
1016         struct fw_card *card = device->card;
1017         int node_id = device->node_id;
1018
1019         switch (reread_bus_info_block(device, device->generation)) {
1020         case REREAD_BIB_ERROR:
1021                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
1022                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1023                         device->config_rom_retries++;
1024                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
1025
1026                         return;
1027                 }
1028                 goto give_up;
1029
1030         case REREAD_BIB_GONE:
1031                 goto gone;
1032
1033         case REREAD_BIB_UNCHANGED:
1034                 if (atomic_cmpxchg(&device->state,
1035                                    FW_DEVICE_INITIALIZING,
1036                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1037                         goto gone;
1038
1039                 fw_device_update(work);
1040                 device->config_rom_retries = 0;
1041                 goto out;
1042
1043         case REREAD_BIB_CHANGED:
1044                 break;
1045         }
1046
1047         /*
1048          * Something changed.  We keep things simple and don't investigate
1049          * further.  We just destroy all previous units and create new ones.
1050          */
1051         device_for_each_child(&device->device, NULL, shutdown_unit);
1052
1053         if (read_bus_info_block(device, device->generation) < 0) {
1054                 if (device->config_rom_retries < MAX_RETRIES &&
1055                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1056                         device->config_rom_retries++;
1057                         schedule_delayed_work(&device->work, RETRY_DELAY);
1058
1059                         return;
1060                 }
1061                 goto give_up;
1062         }
1063
1064         create_units(device);
1065
1066         /* Userspace may want to re-read attributes. */
1067         kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1068
1069         if (atomic_cmpxchg(&device->state,
1070                            FW_DEVICE_INITIALIZING,
1071                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1072                 goto gone;
1073
1074         fw_notify("refreshed device %s\n", dev_name(&device->device));
1075         device->config_rom_retries = 0;
1076         goto out;
1077
1078  give_up:
1079         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
1080  gone:
1081         atomic_set(&device->state, FW_DEVICE_GONE);
1082         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1083         schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
1084  out:
1085         if (node_id == card->root_node->node_id)
1086                 fw_schedule_bm_work(card, 0);
1087 }
1088
1089 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1090 {
1091         struct fw_device *device;
1092
1093         switch (event) {
1094         case FW_NODE_CREATED:
1095         case FW_NODE_LINK_ON:
1096                 if (!node->link_on)
1097                         break;
1098  create:
1099                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
1100                 if (device == NULL)
1101                         break;
1102
1103                 /*
1104                  * Do minimal intialization of the device here, the
1105                  * rest will happen in fw_device_init().
1106                  *
1107                  * Attention:  A lot of things, even fw_device_get(),
1108                  * cannot be done before fw_device_init() finished!
1109                  * You can basically just check device->state and
1110                  * schedule work until then, but only while holding
1111                  * card->lock.
1112                  */
1113                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1114                 device->card = fw_card_get(card);
1115                 device->node = fw_node_get(node);
1116                 device->node_id = node->node_id;
1117                 device->generation = card->generation;
1118                 device->is_local = node == card->local_node;
1119                 mutex_init(&device->client_list_mutex);
1120                 INIT_LIST_HEAD(&device->client_list);
1121
1122                 /*
1123                  * Set the node data to point back to this device so
1124                  * FW_NODE_UPDATED callbacks can update the node_id
1125                  * and generation for the device.
1126                  */
1127                 node->data = device;
1128
1129                 /*
1130                  * Many devices are slow to respond after bus resets,
1131                  * especially if they are bus powered and go through
1132                  * power-up after getting plugged in.  We schedule the
1133                  * first config rom scan half a second after bus reset.
1134                  */
1135                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1136                 schedule_delayed_work(&device->work, INITIAL_DELAY);
1137                 break;
1138
1139         case FW_NODE_INITIATED_RESET:
1140                 device = node->data;
1141                 if (device == NULL)
1142                         goto create;
1143
1144                 device->node_id = node->node_id;
1145                 smp_wmb();  /* update node_id before generation */
1146                 device->generation = card->generation;
1147                 if (atomic_cmpxchg(&device->state,
1148                             FW_DEVICE_RUNNING,
1149                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1150                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1151                         schedule_delayed_work(&device->work,
1152                                 device->is_local ? 0 : INITIAL_DELAY);
1153                 }
1154                 break;
1155
1156         case FW_NODE_UPDATED:
1157                 if (!node->link_on || node->data == NULL)
1158                         break;
1159
1160                 device = node->data;
1161                 device->node_id = node->node_id;
1162                 smp_wmb();  /* update node_id before generation */
1163                 device->generation = card->generation;
1164                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1165                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1166                         schedule_delayed_work(&device->work, 0);
1167                 }
1168                 break;
1169
1170         case FW_NODE_DESTROYED:
1171         case FW_NODE_LINK_OFF:
1172                 if (!node->data)
1173                         break;
1174
1175                 /*
1176                  * Destroy the device associated with the node.  There
1177                  * are two cases here: either the device is fully
1178                  * initialized (FW_DEVICE_RUNNING) or we're in the
1179                  * process of reading its config rom
1180                  * (FW_DEVICE_INITIALIZING).  If it is fully
1181                  * initialized we can reuse device->work to schedule a
1182                  * full fw_device_shutdown().  If not, there's work
1183                  * scheduled to read it's config rom, and we just put
1184                  * the device in shutdown state to have that code fail
1185                  * to create the device.
1186                  */
1187                 device = node->data;
1188                 if (atomic_xchg(&device->state,
1189                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1190                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1191                         schedule_delayed_work(&device->work,
1192                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1193                 }
1194                 break;
1195         }
1196 }