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 bool 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_parent_device(unit);
  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_parent_device(unit);
 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 = (const struct attribute_group **) 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->max_rec = rom[2] >> 12 & 0xf;
 584         device->cmc     = rom[2] >> 30 & 1;
 585         device->irmc    = rom[2] >> 31 & 1;
 586  out:
 587         kfree(rom);
 588
 589         return ret;
 590 }
 591
 592 static void fw_unit_release(struct device *dev)
 593 {
 594         struct fw_unit *unit = fw_unit(dev);
 595
 596         kfree(unit);
 597 }
 598
 599 static struct device_type fw_unit_type = {
 600         .uevent         = fw_unit_uevent,
 601         .release        = fw_unit_release,
 602 };
 603
 604 static bool is_fw_unit(struct device *dev)
 605 {
 606         return dev->type == &fw_unit_type;
 607 }
 608
 609 static void create_units(struct fw_device *device)
 610 {
 611         struct fw_csr_iterator ci;
 612         struct fw_unit *unit;
 613         int key, value, i;
 614
 615         i = 0;
 616         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 617         while (fw_csr_iterator_next(&ci, &key, &value)) {
 618                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 619                         continue;
 620
 621                 /*
 622                  * Get the address of the unit directory and try to
 623                  * match the drivers id_tables against it.
 624                  */
 625                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 626                 if (unit == NULL) {
 627                         fw_error("failed to allocate memory for unit\n");
 628                         continue;
 629                 }
 630
 631                 unit->directory = ci.p + value - 1;
 632                 unit->device.bus = &fw_bus_type;
 633                 unit->device.type = &fw_unit_type;
 634                 unit->device.parent = &device->device;
 635                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
 636
 637                 BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
 638                                 ARRAY_SIZE(fw_unit_attributes) +
 639                                 ARRAY_SIZE(config_rom_attributes));
 640                 init_fw_attribute_group(&unit->device,
 641                                         fw_unit_attributes,
 642                                         &unit->attribute_group);
 643
 644                 if (device_register(&unit->device) < 0)
 645                         goto skip_unit;
 646
 647                 continue;
 648
 649         skip_unit:
 650                 kfree(unit);
 651         }
 652 }
 653
 654 static int shutdown_unit(struct device *device, void *data)
 655 {
 656         device_unregister(device);
 657
 658         return 0;
 659 }
 660
 661 /*
 662  * fw_device_rwsem acts as dual purpose mutex:
 663  *   - serializes accesses to fw_device_idr,
 664  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 665  *     fw_unit.directory, unless those accesses happen at safe occasions
 666  */
 667 DECLARE_RWSEM(fw_device_rwsem);
 668
 669 DEFINE_IDR(fw_device_idr);
 670 int fw_cdev_major;
 671
 672 struct fw_device *fw_device_get_by_devt(dev_t devt)
 673 {
 674         struct fw_device *device;
 675
 676         down_read(&fw_device_rwsem);
 677         device = idr_find(&fw_device_idr, MINOR(devt));
 678         if (device)
 679                 fw_device_get(device);
 680         up_read(&fw_device_rwsem);
 681
 682         return device;
 683 }
 684
 685 /*
 686  * These defines control the retry behavior for reading the config
 687  * rom.  It shouldn't be necessary to tweak these; if the device
 688  * doesn't respond to a config rom read within 10 seconds, it's not
 689  * going to respond at all.  As for the initial delay, a lot of
 690  * devices will be able to respond within half a second after bus
 691  * reset.  On the other hand, it's not really worth being more
 692  * aggressive than that, since it scales pretty well; if 10 devices
 693  * are plugged in, they're all getting read within one second.
 694  */
 695
 696 #define MAX_RETRIES     10
 697 #define RETRY_DELAY     (3 * HZ)
 698 #define INITIAL_DELAY   (HZ / 2)
 699 #define SHUTDOWN_DELAY  (2 * HZ)
 700
 701 static void fw_device_shutdown(struct work_struct *work)
 702 {
 703         struct fw_device *device =
 704                 container_of(work, struct fw_device, work.work);
 705         int minor = MINOR(device->device.devt);
 706
 707         if (time_is_after_jiffies(device->card->reset_jiffies + SHUTDOWN_DELAY)
 708             && !list_empty(&device->card->link)) {
 709                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 710                 return;
 711         }
 712
 713         if (atomic_cmpxchg(&device->state,
 714                            FW_DEVICE_GONE,
 715                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
 716                 return;
 717
 718         fw_device_cdev_remove(device);
 719         device_for_each_child(&device->device, NULL, shutdown_unit);
 720         device_unregister(&device->device);
 721
 722         down_write(&fw_device_rwsem);
 723         idr_remove(&fw_device_idr, minor);
 724         up_write(&fw_device_rwsem);
 725
 726         fw_device_put(device);
 727 }
 728
 729 static void fw_device_release(struct device *dev)
 730 {
 731         struct fw_device *device = fw_device(dev);
 732         struct fw_card *card = device->card;
 733         unsigned long flags;
 734
 735         /*
 736          * Take the card lock so we don't set this to NULL while a
 737          * FW_NODE_UPDATED callback is being handled or while the
 738          * bus manager work looks at this node.
 739          */
 740         spin_lock_irqsave(&card->lock, flags);
 741         device->node->data = NULL;
 742         spin_unlock_irqrestore(&card->lock, flags);
 743
 744         fw_node_put(device->node);
 745         kfree(device->config_rom);
 746         kfree(device);
 747         fw_card_put(card);
 748 }
 749
 750 static struct device_type fw_device_type = {
 751         .release = fw_device_release,
 752 };
 753
 754 static bool is_fw_device(struct device *dev)
 755 {
 756         return dev->type == &fw_device_type;
 757 }
 758
 759 static int update_unit(struct device *dev, void *data)
 760 {
 761         struct fw_unit *unit = fw_unit(dev);
 762         struct fw_driver *driver = (struct fw_driver *)dev->driver;
 763
 764         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
 765                 down(&dev->sem);
 766                 driver->update(unit);
 767                 up(&dev->sem);
 768         }
 769
 770         return 0;
 771 }
 772
 773 static void fw_device_update(struct work_struct *work)
 774 {
 775         struct fw_device *device =
 776                 container_of(work, struct fw_device, work.work);
 777
 778         fw_device_cdev_update(device);
 779         device_for_each_child(&device->device, NULL, update_unit);
 780 }
 781
 782 /*
 783  * If a device was pending for deletion because its node went away but its
 784  * bus info block and root directory header matches that of a newly discovered
 785  * device, revive the existing fw_device.
 786  * The newly allocated fw_device becomes obsolete instead.
 787  */
 788 static int lookup_existing_device(struct device *dev, void *data)
 789 {
 790         struct fw_device *old = fw_device(dev);
 791         struct fw_device *new = data;
 792         struct fw_card *card = new->card;
 793         int match = 0;
 794
 795         if (!is_fw_device(dev))
 796                 return 0;
 797
 798         down_read(&fw_device_rwsem); /* serialize config_rom access */
 799         spin_lock_irq(&card->lock);  /* serialize node access */
 800
 801         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
 802             atomic_cmpxchg(&old->state,
 803                            FW_DEVICE_GONE,
 804                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 805                 struct fw_node *current_node = new->node;
 806                 struct fw_node *obsolete_node = old->node;
 807
 808                 new->node = obsolete_node;
 809                 new->node->data = new;
 810                 old->node = current_node;
 811                 old->node->data = old;
 812
 813                 old->max_speed = new->max_speed;
 814                 old->node_id = current_node->node_id;
 815                 smp_wmb();  /* update node_id before generation */
 816                 old->generation = card->generation;
 817                 old->config_rom_retries = 0;
 818                 fw_notify("rediscovered device %s\n", dev_name(dev));
 819
 820                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
 821                 schedule_delayed_work(&old->work, 0);
 822
 823                 if (current_node == card->root_node)
 824                         fw_schedule_bm_work(card, 0);
 825
 826                 match = 1;
 827         }
 828
 829         spin_unlock_irq(&card->lock);
 830         up_read(&fw_device_rwsem);
 831
 832         return match;
 833 }
 834
 835 enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
 836
 837 static void set_broadcast_channel(struct fw_device *device, int generation)
 838 {
 839         struct fw_card *card = device->card;
 840         __be32 data;
 841         int rcode;
 842
 843         if (!card->broadcast_channel_allocated)
 844                 return;
 845
 846         /*
 847          * The Broadcast_Channel Valid bit is required by nodes which want to
 848          * transmit on this channel.  Such transmissions are practically
 849          * exclusive to IP over 1394 (RFC 2734).  IP capable nodes are required
 850          * to be IRM capable and have a max_rec of 8 or more.  We use this fact
 851          * to narrow down to which nodes we send Broadcast_Channel updates.
 852          */
 853         if (!device->irmc || device->max_rec < 8)
 854                 return;
 855
 856         /*
 857          * Some 1394-1995 nodes crash if this 1394a-2000 register is written.
 858          * Perform a read test first.
 859          */
 860         if (device->bc_implemented == BC_UNKNOWN) {
 861                 rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
 862                                 device->node_id, generation, device->max_speed,
 863                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 864                                 &data, 4);
 865                 switch (rcode) {
 866                 case RCODE_COMPLETE:
 867                         if (data & cpu_to_be32(1 << 31)) {
 868                                 device->bc_implemented = BC_IMPLEMENTED;
 869                                 break;
 870                         }
 871                         /* else fall through to case address error */
 872                 case RCODE_ADDRESS_ERROR:
 873                         device->bc_implemented = BC_UNIMPLEMENTED;
 874                 }
 875         }
 876
 877         if (device->bc_implemented == BC_IMPLEMENTED) {
 878                 data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
 879                                    BROADCAST_CHANNEL_VALID);
 880                 fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
 881                                 device->node_id, generation, device->max_speed,
 882                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 883                                 &data, 4);
 884         }
 885 }
 886
 887 int fw_device_set_broadcast_channel(struct device *dev, void *gen)
 888 {
 889         if (is_fw_device(dev))
 890                 set_broadcast_channel(fw_device(dev), (long)gen);
 891
 892         return 0;
 893 }
 894
 895 static void fw_device_init(struct work_struct *work)
 896 {
 897         struct fw_device *device =
 898                 container_of(work, struct fw_device, work.work);
 899         struct device *revived_dev;
 900         int minor, ret;
 901
 902         /*
 903          * All failure paths here set node->data to NULL, so that we
 904          * don't try to do device_for_each_child() on a kfree()'d
 905          * device.
 906          */
 907
 908         if (read_bus_info_block(device, device->generation) < 0) {
 909                 if (device->config_rom_retries < MAX_RETRIES &&
 910                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 911                         device->config_rom_retries++;
 912                         schedule_delayed_work(&device->work, RETRY_DELAY);
 913                 } else {
 914                         fw_notify("giving up on config rom for node id %x\n",
 915                                   device->node_id);
 916                         if (device->node == device->card->root_node)
 917                                 fw_schedule_bm_work(device->card, 0);
 918                         fw_device_release(&device->device);
 919                 }
 920                 return;
 921         }
 922
 923         revived_dev = device_find_child(device->card->device,
 924                                         device, lookup_existing_device);
 925         if (revived_dev) {
 926                 put_device(revived_dev);
 927                 fw_device_release(&device->device);
 928
 929                 return;
 930         }
 931
 932         device_initialize(&device->device);
 933
 934         fw_device_get(device);
 935         down_write(&fw_device_rwsem);
 936         ret = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
 937               idr_get_new(&fw_device_idr, device, &minor) :
 938               -ENOMEM;
 939         up_write(&fw_device_rwsem);
 940
 941         if (ret < 0)
 942                 goto error;
 943
 944         device->device.bus = &fw_bus_type;
 945         device->device.type = &fw_device_type;
 946         device->device.parent = device->card->device;
 947         device->device.devt = MKDEV(fw_cdev_major, minor);
 948         dev_set_name(&device->device, "fw%d", minor);
 949
 950         BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
 951                         ARRAY_SIZE(fw_device_attributes) +
 952                         ARRAY_SIZE(config_rom_attributes));
 953         init_fw_attribute_group(&device->device,
 954                                 fw_device_attributes,
 955                                 &device->attribute_group);
 956
 957         if (device_add(&device->device)) {
 958                 fw_error("Failed to add device.\n");
 959                 goto error_with_cdev;
 960         }
 961
 962         create_units(device);
 963
 964         /*
 965          * Transition the device to running state.  If it got pulled
 966          * out from under us while we did the intialization work, we
 967          * have to shut down the device again here.  Normally, though,
 968          * fw_node_event will be responsible for shutting it down when
 969          * necessary.  We have to use the atomic cmpxchg here to avoid
 970          * racing with the FW_NODE_DESTROYED case in
 971          * fw_node_event().
 972          */
 973         if (atomic_cmpxchg(&device->state,
 974                            FW_DEVICE_INITIALIZING,
 975                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 976                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
 977                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 978         } else {
 979                 if (device->config_rom_retries)
 980                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
 981                                   "%d config ROM retries\n",
 982                                   dev_name(&device->device),
 983                                   device->config_rom[3], device->config_rom[4],
 984                                   1 << device->max_speed,
 985                                   device->config_rom_retries);
 986                 else
 987                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
 988                                   dev_name(&device->device),
 989                                   device->config_rom[3], device->config_rom[4],
 990                                   1 << device->max_speed);
 991                 device->config_rom_retries = 0;
 992
 993                 set_broadcast_channel(device, device->generation);
 994         }
 995
 996         /*
 997          * Reschedule the IRM work if we just finished reading the
 998          * root node config rom.  If this races with a bus reset we
 999          * just end up running the IRM work a couple of extra times -
1000          * pretty harmless.
1001          */
1002         if (device->node == device->card->root_node)
1003                 fw_schedule_bm_work(device->card, 0);
1004
1005         return;
1006
1007  error_with_cdev:
1008         down_write(&fw_device_rwsem);
1009         idr_remove(&fw_device_idr, minor);
1010         up_write(&fw_device_rwsem);
1011  error:
1012         fw_device_put(device);          /* fw_device_idr's reference */
1013
1014         put_device(&device->device);    /* our reference */
1015 }
1016
1017 enum {
1018         REREAD_BIB_ERROR,
1019         REREAD_BIB_GONE,
1020         REREAD_BIB_UNCHANGED,
1021         REREAD_BIB_CHANGED,
1022 };
1023
1024 /* Reread and compare bus info block and header of root directory */
1025 static int reread_bus_info_block(struct fw_device *device, int generation)
1026 {
1027         u32 q;
1028         int i;
1029
1030         for (i = 0; i < 6; i++) {
1031                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
1032                         return REREAD_BIB_ERROR;
1033
1034                 if (i == 0 && q == 0)
1035                         return REREAD_BIB_GONE;
1036
1037                 if (q != device->config_rom[i])
1038                         return REREAD_BIB_CHANGED;
1039         }
1040
1041         return REREAD_BIB_UNCHANGED;
1042 }
1043
1044 static void fw_device_refresh(struct work_struct *work)
1045 {
1046         struct fw_device *device =
1047                 container_of(work, struct fw_device, work.work);
1048         struct fw_card *card = device->card;
1049         int node_id = device->node_id;
1050
1051         switch (reread_bus_info_block(device, device->generation)) {
1052         case REREAD_BIB_ERROR:
1053                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
1054                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1055                         device->config_rom_retries++;
1056                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
1057
1058                         return;
1059                 }
1060                 goto give_up;
1061
1062         case REREAD_BIB_GONE:
1063                 goto gone;
1064
1065         case REREAD_BIB_UNCHANGED:
1066                 if (atomic_cmpxchg(&device->state,
1067                                    FW_DEVICE_INITIALIZING,
1068                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1069                         goto gone;
1070
1071                 fw_device_update(work);
1072                 device->config_rom_retries = 0;
1073                 goto out;
1074
1075         case REREAD_BIB_CHANGED:
1076                 break;
1077         }
1078
1079         /*
1080          * Something changed.  We keep things simple and don't investigate
1081          * further.  We just destroy all previous units and create new ones.
1082          */
1083         device_for_each_child(&device->device, NULL, shutdown_unit);
1084
1085         if (read_bus_info_block(device, device->generation) < 0) {
1086                 if (device->config_rom_retries < MAX_RETRIES &&
1087                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1088                         device->config_rom_retries++;
1089                         schedule_delayed_work(&device->work, RETRY_DELAY);
1090
1091                         return;
1092                 }
1093                 goto give_up;
1094         }
1095
1096         create_units(device);
1097
1098         /* Userspace may want to re-read attributes. */
1099         kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1100
1101         if (atomic_cmpxchg(&device->state,
1102                            FW_DEVICE_INITIALIZING,
1103                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1104                 goto gone;
1105
1106         fw_notify("refreshed device %s\n", dev_name(&device->device));
1107         device->config_rom_retries = 0;
1108         goto out;
1109
1110  give_up:
1111         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
1112  gone:
1113         atomic_set(&device->state, FW_DEVICE_GONE);
1114         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1115         schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
1116  out:
1117         if (node_id == card->root_node->node_id)
1118                 fw_schedule_bm_work(card, 0);
1119 }
1120
1121 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1122 {
1123         struct fw_device *device;
1124
1125         switch (event) {
1126         case FW_NODE_CREATED:
1127         case FW_NODE_LINK_ON:
1128                 if (!node->link_on)
1129                         break;
1130  create:
1131                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
1132                 if (device == NULL)
1133                         break;
1134
1135                 /*
1136                  * Do minimal intialization of the device here, the
1137                  * rest will happen in fw_device_init().
1138                  *
1139                  * Attention:  A lot of things, even fw_device_get(),
1140                  * cannot be done before fw_device_init() finished!
1141                  * You can basically just check device->state and
1142                  * schedule work until then, but only while holding
1143                  * card->lock.
1144                  */
1145                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1146                 device->card = fw_card_get(card);
1147                 device->node = fw_node_get(node);
1148                 device->node_id = node->node_id;
1149                 device->generation = card->generation;
1150                 device->is_local = node == card->local_node;
1151                 mutex_init(&device->client_list_mutex);
1152                 INIT_LIST_HEAD(&device->client_list);
1153
1154                 /*
1155                  * Set the node data to point back to this device so
1156                  * FW_NODE_UPDATED callbacks can update the node_id
1157                  * and generation for the device.
1158                  */
1159                 node->data = device;
1160
1161                 /*
1162                  * Many devices are slow to respond after bus resets,
1163                  * especially if they are bus powered and go through
1164                  * power-up after getting plugged in.  We schedule the
1165                  * first config rom scan half a second after bus reset.
1166                  */
1167                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1168                 schedule_delayed_work(&device->work, INITIAL_DELAY);
1169                 break;
1170
1171         case FW_NODE_INITIATED_RESET:
1172                 device = node->data;
1173                 if (device == NULL)
1174                         goto create;
1175
1176                 device->node_id = node->node_id;
1177                 smp_wmb();  /* update node_id before generation */
1178                 device->generation = card->generation;
1179                 if (atomic_cmpxchg(&device->state,
1180                             FW_DEVICE_RUNNING,
1181                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1182                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1183                         schedule_delayed_work(&device->work,
1184                                 device->is_local ? 0 : INITIAL_DELAY);
1185                 }
1186                 break;
1187
1188         case FW_NODE_UPDATED:
1189                 if (!node->link_on || node->data == NULL)
1190                         break;
1191
1192                 device = node->data;
1193                 device->node_id = node->node_id;
1194                 smp_wmb();  /* update node_id before generation */
1195                 device->generation = card->generation;
1196                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1197                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1198                         schedule_delayed_work(&device->work, 0);
1199                 }
1200                 break;
1201
1202         case FW_NODE_DESTROYED:
1203         case FW_NODE_LINK_OFF:
1204                 if (!node->data)
1205                         break;
1206
1207                 /*
1208                  * Destroy the device associated with the node.  There
1209                  * are two cases here: either the device is fully
1210                  * initialized (FW_DEVICE_RUNNING) or we're in the
1211                  * process of reading its config rom
1212                  * (FW_DEVICE_INITIALIZING).  If it is fully
1213                  * initialized we can reuse device->work to schedule a
1214                  * full fw_device_shutdown().  If not, there's work
1215                  * scheduled to read it's config rom, and we just put
1216                  * the device in shutdown state to have that code fail
1217                  * to create the device.
1218                  */
1219                 device = node->data;
1220                 if (atomic_xchg(&device->state,
1221                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1222                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1223                         schedule_delayed_work(&device->work,
1224                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1225                 }
1226                 break;
1227         }
1228 }