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/bug.h>
  22 #include <linux/ctype.h>
  23 #include <linux/delay.h>
  24 #include <linux/device.h>
  25 #include <linux/errno.h>
  26 #include <linux/firewire.h>
  27 #include <linux/firewire-constants.h>
  28 #include <linux/idr.h>
  29 #include <linux/jiffies.h>
  30 #include <linux/kobject.h>
  31 #include <linux/list.h>
  32 #include <linux/mod_devicetable.h>
  33 #include <linux/module.h>
  34 #include <linux/mutex.h>
  35 #include <linux/rwsem.h>
  36 #include <linux/slab.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/string.h>
  39 #include <linux/workqueue.h>
  40
  41 #include <linux/atomic.h>
  42 #include <asm/byteorder.h>
  43
  44 #include "core.h"
  45
  46 void fw_csr_iterator_init(struct fw_csr_iterator *ci, const 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 const u32 *search_leaf(const u32 *directory, int search_key)
  63 {
  64         struct fw_csr_iterator ci;
  65         int last_key = 0, key, value;
  66
  67         fw_csr_iterator_init(&ci, directory);
  68         while (fw_csr_iterator_next(&ci, &key, &value)) {
  69                 if (last_key == search_key &&
  70                     key == (CSR_DESCRIPTOR | CSR_LEAF))
  71                         return ci.p - 1 + value;
  72
  73                 last_key = key;
  74         }
  75
  76         return NULL;
  77 }
  78
  79 static int textual_leaf_to_string(const u32 *block, char *buf, size_t size)
  80 {
  81         unsigned int quadlets, i;
  82         char c;
  83
  84         if (!size || !buf)
  85                 return -EINVAL;
  86
  87         quadlets = min(block[0] >> 16, 256U);
  88         if (quadlets < 2)
  89                 return -ENODATA;
  90
  91         if (block[1] != 0 || block[2] != 0)
  92                 /* unknown language/character set */
  93                 return -ENODATA;
  94
  95         block += 3;
  96         quadlets -= 2;
  97         for (i = 0; i < quadlets * 4 && i < size - 1; i++) {
  98                 c = block[i / 4] >> (24 - 8 * (i % 4));
  99                 if (c == '\0')
 100                         break;
 101                 buf[i] = c;
 102         }
 103         buf[i] = '\0';
 104
 105         return i;
 106 }
 107
 108 /**
 109  * fw_csr_string() - reads a string from the configuration ROM
 110  * @directory:  e.g. root directory or unit directory
 111  * @key:        the key of the preceding directory entry
 112  * @buf:        where to put the string
 113  * @size:       size of @buf, in bytes
 114  *
 115  * The string is taken from a minimal ASCII text descriptor leaf after
 116  * the immediate entry with @key.  The string is zero-terminated.
 117  * Returns strlen(buf) or a negative error code.
 118  */
 119 int fw_csr_string(const u32 *directory, int key, char *buf, size_t size)
 120 {
 121         const u32 *leaf = search_leaf(directory, key);
 122         if (!leaf)
 123                 return -ENOENT;
 124
 125         return textual_leaf_to_string(leaf, buf, size);
 126 }
 127 EXPORT_SYMBOL(fw_csr_string);
 128
 129 static void get_ids(const u32 *directory, int *id)
 130 {
 131         struct fw_csr_iterator ci;
 132         int key, value;
 133
 134         fw_csr_iterator_init(&ci, directory);
 135         while (fw_csr_iterator_next(&ci, &key, &value)) {
 136                 switch (key) {
 137                 case CSR_VENDOR:        id[0] = value; break;
 138                 case CSR_MODEL:         id[1] = value; break;
 139                 case CSR_SPECIFIER_ID:  id[2] = value; break;
 140                 case CSR_VERSION:       id[3] = value; break;
 141                 }
 142         }
 143 }
 144
 145 static void get_modalias_ids(struct fw_unit *unit, int *id)
 146 {
 147         get_ids(&fw_parent_device(unit)->config_rom[5], id);
 148         get_ids(unit->directory, id);
 149 }
 150
 151 static bool match_ids(const struct ieee1394_device_id *id_table, int *id)
 152 {
 153         int match = 0;
 154
 155         if (id[0] == id_table->vendor_id)
 156                 match |= IEEE1394_MATCH_VENDOR_ID;
 157         if (id[1] == id_table->model_id)
 158                 match |= IEEE1394_MATCH_MODEL_ID;
 159         if (id[2] == id_table->specifier_id)
 160                 match |= IEEE1394_MATCH_SPECIFIER_ID;
 161         if (id[3] == id_table->version)
 162                 match |= IEEE1394_MATCH_VERSION;
 163
 164         return (match & id_table->match_flags) == id_table->match_flags;
 165 }
 166
 167 static bool is_fw_unit(struct device *dev);
 168
 169 static int fw_unit_match(struct device *dev, struct device_driver *drv)
 170 {
 171         const struct ieee1394_device_id *id_table =
 172                         container_of(drv, struct fw_driver, driver)->id_table;
 173         int id[] = {0, 0, 0, 0};
 174
 175         /* We only allow binding to fw_units. */
 176         if (!is_fw_unit(dev))
 177                 return 0;
 178
 179         get_modalias_ids(fw_unit(dev), id);
 180
 181         for (; id_table->match_flags != 0; id_table++)
 182                 if (match_ids(id_table, id))
 183                         return 1;
 184
 185         return 0;
 186 }
 187
 188 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
 189 {
 190         int id[] = {0, 0, 0, 0};
 191
 192         get_modalias_ids(unit, id);
 193
 194         return snprintf(buffer, buffer_size,
 195                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
 196                         id[0], id[1], id[2], id[3]);
 197 }
 198
 199 static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 200 {
 201         struct fw_unit *unit = fw_unit(dev);
 202         char modalias[64];
 203
 204         get_modalias(unit, modalias, sizeof(modalias));
 205
 206         if (add_uevent_var(env, "MODALIAS=%s", modalias))
 207                 return -ENOMEM;
 208
 209         return 0;
 210 }
 211
 212 struct bus_type fw_bus_type = {
 213         .name = "firewire",
 214         .match = fw_unit_match,
 215 };
 216 EXPORT_SYMBOL(fw_bus_type);
 217
 218 int fw_device_enable_phys_dma(struct fw_device *device)
 219 {
 220         int generation = device->generation;
 221
 222         /* device->node_id, accessed below, must not be older than generation */
 223         smp_rmb();
 224
 225         return device->card->driver->enable_phys_dma(device->card,
 226                                                      device->node_id,
 227                                                      generation);
 228 }
 229 EXPORT_SYMBOL(fw_device_enable_phys_dma);
 230
 231 struct config_rom_attribute {
 232         struct device_attribute attr;
 233         u32 key;
 234 };
 235
 236 static ssize_t show_immediate(struct device *dev,
 237                               struct device_attribute *dattr, char *buf)
 238 {
 239         struct config_rom_attribute *attr =
 240                 container_of(dattr, struct config_rom_attribute, attr);
 241         struct fw_csr_iterator ci;
 242         const u32 *dir;
 243         int key, value, ret = -ENOENT;
 244
 245         down_read(&fw_device_rwsem);
 246
 247         if (is_fw_unit(dev))
 248                 dir = fw_unit(dev)->directory;
 249         else
 250                 dir = fw_device(dev)->config_rom + 5;
 251
 252         fw_csr_iterator_init(&ci, dir);
 253         while (fw_csr_iterator_next(&ci, &key, &value))
 254                 if (attr->key == key) {
 255                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
 256                                        "0x%06x\n", value);
 257                         break;
 258                 }
 259
 260         up_read(&fw_device_rwsem);
 261
 262         return ret;
 263 }
 264
 265 #define IMMEDIATE_ATTR(name, key)                               \
 266         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
 267
 268 static ssize_t show_text_leaf(struct device *dev,
 269                               struct device_attribute *dattr, char *buf)
 270 {
 271         struct config_rom_attribute *attr =
 272                 container_of(dattr, struct config_rom_attribute, attr);
 273         const u32 *dir;
 274         size_t bufsize;
 275         char dummy_buf[2];
 276         int ret;
 277
 278         down_read(&fw_device_rwsem);
 279
 280         if (is_fw_unit(dev))
 281                 dir = fw_unit(dev)->directory;
 282         else
 283                 dir = fw_device(dev)->config_rom + 5;
 284
 285         if (buf) {
 286                 bufsize = PAGE_SIZE - 1;
 287         } else {
 288                 buf = dummy_buf;
 289                 bufsize = 1;
 290         }
 291
 292         ret = fw_csr_string(dir, attr->key, buf, bufsize);
 293
 294         if (ret >= 0) {
 295                 /* Strip trailing whitespace and add newline. */
 296                 while (ret > 0 && isspace(buf[ret - 1]))
 297                         ret--;
 298                 strcpy(buf + ret, "\n");
 299                 ret++;
 300         }
 301
 302         up_read(&fw_device_rwsem);
 303
 304         return ret;
 305 }
 306
 307 #define TEXT_LEAF_ATTR(name, key)                               \
 308         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
 309
 310 static struct config_rom_attribute config_rom_attributes[] = {
 311         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
 312         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
 313         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
 314         IMMEDIATE_ATTR(version, CSR_VERSION),
 315         IMMEDIATE_ATTR(model, CSR_MODEL),
 316         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
 317         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
 318         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
 319 };
 320
 321 static void init_fw_attribute_group(struct device *dev,
 322                                     struct device_attribute *attrs,
 323                                     struct fw_attribute_group *group)
 324 {
 325         struct device_attribute *attr;
 326         int i, j;
 327
 328         for (j = 0; attrs[j].attr.name != NULL; j++)
 329                 group->attrs[j] = &attrs[j].attr;
 330
 331         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
 332                 attr = &config_rom_attributes[i].attr;
 333                 if (attr->show(dev, attr, NULL) < 0)
 334                         continue;
 335                 group->attrs[j++] = &attr->attr;
 336         }
 337
 338         group->attrs[j] = NULL;
 339         group->groups[0] = &group->group;
 340         group->groups[1] = NULL;
 341         group->group.attrs = group->attrs;
 342         dev->groups = (const struct attribute_group **) group->groups;
 343 }
 344
 345 static ssize_t modalias_show(struct device *dev,
 346                              struct device_attribute *attr, char *buf)
 347 {
 348         struct fw_unit *unit = fw_unit(dev);
 349         int length;
 350
 351         length = get_modalias(unit, buf, PAGE_SIZE);
 352         strcpy(buf + length, "\n");
 353
 354         return length + 1;
 355 }
 356
 357 static ssize_t rom_index_show(struct device *dev,
 358                               struct device_attribute *attr, char *buf)
 359 {
 360         struct fw_device *device = fw_device(dev->parent);
 361         struct fw_unit *unit = fw_unit(dev);
 362
 363         return snprintf(buf, PAGE_SIZE, "%d\n",
 364                         (int)(unit->directory - device->config_rom));
 365 }
 366
 367 static struct device_attribute fw_unit_attributes[] = {
 368         __ATTR_RO(modalias),
 369         __ATTR_RO(rom_index),
 370         __ATTR_NULL,
 371 };
 372
 373 static ssize_t config_rom_show(struct device *dev,
 374                                struct device_attribute *attr, char *buf)
 375 {
 376         struct fw_device *device = fw_device(dev);
 377         size_t length;
 378
 379         down_read(&fw_device_rwsem);
 380         length = device->config_rom_length * 4;
 381         memcpy(buf, device->config_rom, length);
 382         up_read(&fw_device_rwsem);
 383
 384         return length;
 385 }
 386
 387 static ssize_t guid_show(struct device *dev,
 388                          struct device_attribute *attr, char *buf)
 389 {
 390         struct fw_device *device = fw_device(dev);
 391         int ret;
 392
 393         down_read(&fw_device_rwsem);
 394         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
 395                        device->config_rom[3], device->config_rom[4]);
 396         up_read(&fw_device_rwsem);
 397
 398         return ret;
 399 }
 400
 401 static int units_sprintf(char *buf, const u32 *directory)
 402 {
 403         struct fw_csr_iterator ci;
 404         int key, value;
 405         int specifier_id = 0;
 406         int version = 0;
 407
 408         fw_csr_iterator_init(&ci, directory);
 409         while (fw_csr_iterator_next(&ci, &key, &value)) {
 410                 switch (key) {
 411                 case CSR_SPECIFIER_ID:
 412                         specifier_id = value;
 413                         break;
 414                 case CSR_VERSION:
 415                         version = value;
 416                         break;
 417                 }
 418         }
 419
 420         return sprintf(buf, "0x%06x:0x%06x ", specifier_id, version);
 421 }
 422
 423 static ssize_t units_show(struct device *dev,
 424                           struct device_attribute *attr, char *buf)
 425 {
 426         struct fw_device *device = fw_device(dev);
 427         struct fw_csr_iterator ci;
 428         int key, value, i = 0;
 429
 430         down_read(&fw_device_rwsem);
 431         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 432         while (fw_csr_iterator_next(&ci, &key, &value)) {
 433                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 434                         continue;
 435                 i += units_sprintf(&buf[i], ci.p + value - 1);
 436                 if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
 437                         break;
 438         }
 439         up_read(&fw_device_rwsem);
 440
 441         if (i)
 442                 buf[i - 1] = '\n';
 443
 444         return i;
 445 }
 446
 447 static struct device_attribute fw_device_attributes[] = {
 448         __ATTR_RO(config_rom),
 449         __ATTR_RO(guid),
 450         __ATTR_RO(units),
 451         __ATTR_NULL,
 452 };
 453
 454 static int read_rom(struct fw_device *device,
 455                     int generation, int index, u32 *data)
 456 {
 457         u64 offset = (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4;
 458         int i, rcode;
 459
 460         /* device->node_id, accessed below, must not be older than generation */
 461         smp_rmb();
 462
 463         for (i = 10; i < 100; i += 10) {
 464                 rcode = fw_run_transaction(device->card,
 465                                 TCODE_READ_QUADLET_REQUEST, device->node_id,
 466                                 generation, device->max_speed, offset, data, 4);
 467                 if (rcode != RCODE_BUSY)
 468                         break;
 469                 msleep(i);
 470         }
 471         be32_to_cpus(data);
 472
 473         return rcode;
 474 }
 475
 476 #define MAX_CONFIG_ROM_SIZE 256
 477
 478 /*
 479  * Read the bus info block, perform a speed probe, and read all of the rest of
 480  * the config ROM.  We do all this with a cached bus generation.  If the bus
 481  * generation changes under us, read_config_rom will fail and get retried.
 482  * It's better to start all over in this case because the node from which we
 483  * are reading the ROM may have changed the ROM during the reset.
 484  * Returns either a result code or a negative error code.
 485  */
 486 static int read_config_rom(struct fw_device *device, int generation)
 487 {
 488         struct fw_card *card = device->card;
 489         const u32 *old_rom, *new_rom;
 490         u32 *rom, *stack;
 491         u32 sp, key;
 492         int i, end, length, ret;
 493
 494         rom = kmalloc(sizeof(*rom) * MAX_CONFIG_ROM_SIZE +
 495                       sizeof(*stack) * MAX_CONFIG_ROM_SIZE, GFP_KERNEL);
 496         if (rom == NULL)
 497                 return -ENOMEM;
 498
 499         stack = &rom[MAX_CONFIG_ROM_SIZE];
 500         memset(rom, 0, sizeof(*rom) * MAX_CONFIG_ROM_SIZE);
 501
 502         device->max_speed = SCODE_100;
 503
 504         /* First read the bus info block. */
 505         for (i = 0; i < 5; i++) {
 506                 ret = read_rom(device, generation, i, &rom[i]);
 507                 if (ret != RCODE_COMPLETE)
 508                         goto out;
 509                 /*
 510                  * As per IEEE1212 7.2, during initialization, devices can
 511                  * reply with a 0 for the first quadlet of the config
 512                  * rom to indicate that they are booting (for example,
 513                  * if the firmware is on the disk of a external
 514                  * harddisk).  In that case we just fail, and the
 515                  * retry mechanism will try again later.
 516                  */
 517                 if (i == 0 && rom[i] == 0) {
 518                         ret = RCODE_BUSY;
 519                         goto out;
 520                 }
 521         }
 522
 523         device->max_speed = device->node->max_speed;
 524
 525         /*
 526          * Determine the speed of
 527          *   - devices with link speed less than PHY speed,
 528          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
 529          *   - all devices if there are 1394b repeaters.
 530          * Note, we cannot use the bus info block's link_spd as starting point
 531          * because some buggy firmwares set it lower than necessary and because
 532          * 1394-1995 nodes do not have the field.
 533          */
 534         if ((rom[2] & 0x7) < device->max_speed ||
 535             device->max_speed == SCODE_BETA ||
 536             card->beta_repeaters_present) {
 537                 u32 dummy;
 538
 539                 /* for S1600 and S3200 */
 540                 if (device->max_speed == SCODE_BETA)
 541                         device->max_speed = card->link_speed;
 542
 543                 while (device->max_speed > SCODE_100) {
 544                         if (read_rom(device, generation, 0, &dummy) ==
 545                             RCODE_COMPLETE)
 546                                 break;
 547                         device->max_speed--;
 548                 }
 549         }
 550
 551         /*
 552          * Now parse the config rom.  The config rom is a recursive
 553          * directory structure so we parse it using a stack of
 554          * references to the blocks that make up the structure.  We
 555          * push a reference to the root directory on the stack to
 556          * start things off.
 557          */
 558         length = i;
 559         sp = 0;
 560         stack[sp++] = 0xc0000005;
 561         while (sp > 0) {
 562                 /*
 563                  * Pop the next block reference of the stack.  The
 564                  * lower 24 bits is the offset into the config rom,
 565                  * the upper 8 bits are the type of the reference the
 566                  * block.
 567                  */
 568                 key = stack[--sp];
 569                 i = key & 0xffffff;
 570                 if (WARN_ON(i >= MAX_CONFIG_ROM_SIZE)) {
 571                         ret = -ENXIO;
 572                         goto out;
 573                 }
 574
 575                 /* Read header quadlet for the block to get the length. */
 576                 ret = read_rom(device, generation, i, &rom[i]);
 577                 if (ret != RCODE_COMPLETE)
 578                         goto out;
 579                 end = i + (rom[i] >> 16) + 1;
 580                 if (end > MAX_CONFIG_ROM_SIZE) {
 581                         /*
 582                          * This block extends outside the config ROM which is
 583                          * a firmware bug.  Ignore this whole block, i.e.
 584                          * simply set a fake block length of 0.
 585                          */
 586                         fw_err(card, "skipped invalid ROM block %x at %llx\n",
 587                                rom[i],
 588                                i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
 589                         rom[i] = 0;
 590                         end = i;
 591                 }
 592                 i++;
 593
 594                 /*
 595                  * Now read in the block.  If this is a directory
 596                  * block, check the entries as we read them to see if
 597                  * it references another block, and push it in that case.
 598                  */
 599                 for (; i < end; i++) {
 600                         ret = read_rom(device, generation, i, &rom[i]);
 601                         if (ret != RCODE_COMPLETE)
 602                                 goto out;
 603
 604                         if ((key >> 30) != 3 || (rom[i] >> 30) < 2)
 605                                 continue;
 606                         /*
 607                          * Offset points outside the ROM.  May be a firmware
 608                          * bug or an Extended ROM entry (IEEE 1212-2001 clause
 609                          * 7.7.18).  Simply overwrite this pointer here by a
 610                          * fake immediate entry so that later iterators over
 611                          * the ROM don't have to check offsets all the time.
 612                          */
 613                         if (i + (rom[i] & 0xffffff) >= MAX_CONFIG_ROM_SIZE) {
 614                                 fw_err(card,
 615                                        "skipped unsupported ROM entry %x at %llx\n",
 616                                        rom[i],
 617                                        i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
 618                                 rom[i] = 0;
 619                                 continue;
 620                         }
 621                         stack[sp++] = i + rom[i];
 622                 }
 623                 if (length < i)
 624                         length = i;
 625         }
 626
 627         old_rom = device->config_rom;
 628         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
 629         if (new_rom == NULL) {
 630                 ret = -ENOMEM;
 631                 goto out;
 632         }
 633
 634         down_write(&fw_device_rwsem);
 635         device->config_rom = new_rom;
 636         device->config_rom_length = length;
 637         up_write(&fw_device_rwsem);
 638
 639         kfree(old_rom);
 640         ret = RCODE_COMPLETE;
 641         device->max_rec = rom[2] >> 12 & 0xf;
 642         device->cmc     = rom[2] >> 30 & 1;
 643         device->irmc    = rom[2] >> 31 & 1;
 644  out:
 645         kfree(rom);
 646
 647         return ret;
 648 }
 649
 650 static void fw_unit_release(struct device *dev)
 651 {
 652         struct fw_unit *unit = fw_unit(dev);
 653
 654         fw_device_put(fw_parent_device(unit));
 655         kfree(unit);
 656 }
 657
 658 static struct device_type fw_unit_type = {
 659         .uevent         = fw_unit_uevent,
 660         .release        = fw_unit_release,
 661 };
 662
 663 static bool is_fw_unit(struct device *dev)
 664 {
 665         return dev->type == &fw_unit_type;
 666 }
 667
 668 static void create_units(struct fw_device *device)
 669 {
 670         struct fw_csr_iterator ci;
 671         struct fw_unit *unit;
 672         int key, value, i;
 673
 674         i = 0;
 675         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 676         while (fw_csr_iterator_next(&ci, &key, &value)) {
 677                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 678                         continue;
 679
 680                 /*
 681                  * Get the address of the unit directory and try to
 682                  * match the drivers id_tables against it.
 683                  */
 684                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 685                 if (unit == NULL) {
 686                         fw_err(device->card, "out of memory for unit\n");
 687                         continue;
 688                 }
 689
 690                 unit->directory = ci.p + value - 1;
 691                 unit->device.bus = &fw_bus_type;
 692                 unit->device.type = &fw_unit_type;
 693                 unit->device.parent = &device->device;
 694                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
 695
 696                 BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
 697                                 ARRAY_SIZE(fw_unit_attributes) +
 698                                 ARRAY_SIZE(config_rom_attributes));
 699                 init_fw_attribute_group(&unit->device,
 700                                         fw_unit_attributes,
 701                                         &unit->attribute_group);
 702
 703                 if (device_register(&unit->device) < 0)
 704                         goto skip_unit;
 705
 706                 fw_device_get(device);
 707                 continue;
 708
 709         skip_unit:
 710                 kfree(unit);
 711         }
 712 }
 713
 714 static int shutdown_unit(struct device *device, void *data)
 715 {
 716         device_unregister(device);
 717
 718         return 0;
 719 }
 720
 721 /*
 722  * fw_device_rwsem acts as dual purpose mutex:
 723  *   - serializes accesses to fw_device_idr,
 724  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 725  *     fw_unit.directory, unless those accesses happen at safe occasions
 726  */
 727 DECLARE_RWSEM(fw_device_rwsem);
 728
 729 DEFINE_IDR(fw_device_idr);
 730 int fw_cdev_major;
 731
 732 struct fw_device *fw_device_get_by_devt(dev_t devt)
 733 {
 734         struct fw_device *device;
 735
 736         down_read(&fw_device_rwsem);
 737         device = idr_find(&fw_device_idr, MINOR(devt));
 738         if (device)
 739                 fw_device_get(device);
 740         up_read(&fw_device_rwsem);
 741
 742         return device;
 743 }
 744
 745 struct workqueue_struct *fw_workqueue;
 746 EXPORT_SYMBOL(fw_workqueue);
 747
 748 static void fw_schedule_device_work(struct fw_device *device,
 749                                     unsigned long delay)
 750 {
 751         queue_delayed_work(fw_workqueue, &device->work, delay);
 752 }
 753
 754 /*
 755  * These defines control the retry behavior for reading the config
 756  * rom.  It shouldn't be necessary to tweak these; if the device
 757  * doesn't respond to a config rom read within 10 seconds, it's not
 758  * going to respond at all.  As for the initial delay, a lot of
 759  * devices will be able to respond within half a second after bus
 760  * reset.  On the other hand, it's not really worth being more
 761  * aggressive than that, since it scales pretty well; if 10 devices
 762  * are plugged in, they're all getting read within one second.
 763  */
 764
 765 #define MAX_RETRIES     10
 766 #define RETRY_DELAY     (3 * HZ)
 767 #define INITIAL_DELAY   (HZ / 2)
 768 #define SHUTDOWN_DELAY  (2 * HZ)
 769
 770 static void fw_device_shutdown(struct work_struct *work)
 771 {
 772         struct fw_device *device =
 773                 container_of(work, struct fw_device, work.work);
 774         int minor = MINOR(device->device.devt);
 775
 776         if (time_before64(get_jiffies_64(),
 777                           device->card->reset_jiffies + SHUTDOWN_DELAY)
 778             && !list_empty(&device->card->link)) {
 779                 fw_schedule_device_work(device, SHUTDOWN_DELAY);
 780                 return;
 781         }
 782
 783         if (atomic_cmpxchg(&device->state,
 784                            FW_DEVICE_GONE,
 785                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
 786                 return;
 787
 788         fw_device_cdev_remove(device);
 789         device_for_each_child(&device->device, NULL, shutdown_unit);
 790         device_unregister(&device->device);
 791
 792         down_write(&fw_device_rwsem);
 793         idr_remove(&fw_device_idr, minor);
 794         up_write(&fw_device_rwsem);
 795
 796         fw_device_put(device);
 797 }
 798
 799 static void fw_device_release(struct device *dev)
 800 {
 801         struct fw_device *device = fw_device(dev);
 802         struct fw_card *card = device->card;
 803         unsigned long flags;
 804
 805         /*
 806          * Take the card lock so we don't set this to NULL while a
 807          * FW_NODE_UPDATED callback is being handled or while the
 808          * bus manager work looks at this node.
 809          */
 810         spin_lock_irqsave(&card->lock, flags);
 811         device->node->data = NULL;
 812         spin_unlock_irqrestore(&card->lock, flags);
 813
 814         fw_node_put(device->node);
 815         kfree(device->config_rom);
 816         kfree(device);
 817         fw_card_put(card);
 818 }
 819
 820 static struct device_type fw_device_type = {
 821         .release = fw_device_release,
 822 };
 823
 824 static bool is_fw_device(struct device *dev)
 825 {
 826         return dev->type == &fw_device_type;
 827 }
 828
 829 static int update_unit(struct device *dev, void *data)
 830 {
 831         struct fw_unit *unit = fw_unit(dev);
 832         struct fw_driver *driver = (struct fw_driver *)dev->driver;
 833
 834         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
 835                 device_lock(dev);
 836                 driver->update(unit);
 837                 device_unlock(dev);
 838         }
 839
 840         return 0;
 841 }
 842
 843 static void fw_device_update(struct work_struct *work)
 844 {
 845         struct fw_device *device =
 846                 container_of(work, struct fw_device, work.work);
 847
 848         fw_device_cdev_update(device);
 849         device_for_each_child(&device->device, NULL, update_unit);
 850 }
 851
 852 /*
 853  * If a device was pending for deletion because its node went away but its
 854  * bus info block and root directory header matches that of a newly discovered
 855  * device, revive the existing fw_device.
 856  * The newly allocated fw_device becomes obsolete instead.
 857  */
 858 static int lookup_existing_device(struct device *dev, void *data)
 859 {
 860         struct fw_device *old = fw_device(dev);
 861         struct fw_device *new = data;
 862         struct fw_card *card = new->card;
 863         int match = 0;
 864
 865         if (!is_fw_device(dev))
 866                 return 0;
 867
 868         down_read(&fw_device_rwsem); /* serialize config_rom access */
 869         spin_lock_irq(&card->lock);  /* serialize node access */
 870
 871         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
 872             atomic_cmpxchg(&old->state,
 873                            FW_DEVICE_GONE,
 874                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 875                 struct fw_node *current_node = new->node;
 876                 struct fw_node *obsolete_node = old->node;
 877
 878                 new->node = obsolete_node;
 879                 new->node->data = new;
 880                 old->node = current_node;
 881                 old->node->data = old;
 882
 883                 old->max_speed = new->max_speed;
 884                 old->node_id = current_node->node_id;
 885                 smp_wmb();  /* update node_id before generation */
 886                 old->generation = card->generation;
 887                 old->config_rom_retries = 0;
 888                 fw_notice(card, "rediscovered device %s\n", dev_name(dev));
 889
 890                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
 891                 fw_schedule_device_work(old, 0);
 892
 893                 if (current_node == card->root_node)
 894                         fw_schedule_bm_work(card, 0);
 895
 896                 match = 1;
 897         }
 898
 899         spin_unlock_irq(&card->lock);
 900         up_read(&fw_device_rwsem);
 901
 902         return match;
 903 }
 904
 905 enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
 906
 907 static void set_broadcast_channel(struct fw_device *device, int generation)
 908 {
 909         struct fw_card *card = device->card;
 910         __be32 data;
 911         int rcode;
 912
 913         if (!card->broadcast_channel_allocated)
 914                 return;
 915
 916         /*
 917          * The Broadcast_Channel Valid bit is required by nodes which want to
 918          * transmit on this channel.  Such transmissions are practically
 919          * exclusive to IP over 1394 (RFC 2734).  IP capable nodes are required
 920          * to be IRM capable and have a max_rec of 8 or more.  We use this fact
 921          * to narrow down to which nodes we send Broadcast_Channel updates.
 922          */
 923         if (!device->irmc || device->max_rec < 8)
 924                 return;
 925
 926         /*
 927          * Some 1394-1995 nodes crash if this 1394a-2000 register is written.
 928          * Perform a read test first.
 929          */
 930         if (device->bc_implemented == BC_UNKNOWN) {
 931                 rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
 932                                 device->node_id, generation, device->max_speed,
 933                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 934                                 &data, 4);
 935                 switch (rcode) {
 936                 case RCODE_COMPLETE:
 937                         if (data & cpu_to_be32(1 << 31)) {
 938                                 device->bc_implemented = BC_IMPLEMENTED;
 939                                 break;
 940                         }
 941                         /* else fall through to case address error */
 942                 case RCODE_ADDRESS_ERROR:
 943                         device->bc_implemented = BC_UNIMPLEMENTED;
 944                 }
 945         }
 946
 947         if (device->bc_implemented == BC_IMPLEMENTED) {
 948                 data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
 949                                    BROADCAST_CHANNEL_VALID);
 950                 fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
 951                                 device->node_id, generation, device->max_speed,
 952                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 953                                 &data, 4);
 954         }
 955 }
 956
 957 int fw_device_set_broadcast_channel(struct device *dev, void *gen)
 958 {
 959         if (is_fw_device(dev))
 960                 set_broadcast_channel(fw_device(dev), (long)gen);
 961
 962         return 0;
 963 }
 964
 965 static void fw_device_init(struct work_struct *work)
 966 {
 967         struct fw_device *device =
 968                 container_of(work, struct fw_device, work.work);
 969         struct fw_card *card = device->card;
 970         struct device *revived_dev;
 971         int minor, ret;
 972
 973         /*
 974          * All failure paths here set node->data to NULL, so that we
 975          * don't try to do device_for_each_child() on a kfree()'d
 976          * device.
 977          */
 978
 979         ret = read_config_rom(device, device->generation);
 980         if (ret != RCODE_COMPLETE) {
 981                 if (device->config_rom_retries < MAX_RETRIES &&
 982                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 983                         device->config_rom_retries++;
 984                         fw_schedule_device_work(device, RETRY_DELAY);
 985                 } else {
 986                         if (device->node->link_on)
 987                                 fw_notice(card, "giving up on node %x: reading config rom failed: %s\n",
 988                                           device->node_id,
 989                                           fw_rcode_string(ret));
 990                         if (device->node == card->root_node)
 991                                 fw_schedule_bm_work(card, 0);
 992                         fw_device_release(&device->device);
 993                 }
 994                 return;
 995         }
 996
 997         revived_dev = device_find_child(card->device,
 998                                         device, lookup_existing_device);
 999         if (revived_dev) {
1000                 put_device(revived_dev);
1001                 fw_device_release(&device->device);
1002
1003                 return;
1004         }
1005
1006         device_initialize(&device->device);
1007
1008         fw_device_get(device);
1009         down_write(&fw_device_rwsem);
1010         ret = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
1011               idr_get_new(&fw_device_idr, device, &minor) :
1012               -ENOMEM;
1013         up_write(&fw_device_rwsem);
1014
1015         if (ret < 0)
1016                 goto error;
1017
1018         device->device.bus = &fw_bus_type;
1019         device->device.type = &fw_device_type;
1020         device->device.parent = card->device;
1021         device->device.devt = MKDEV(fw_cdev_major, minor);
1022         dev_set_name(&device->device, "fw%d", minor);
1023
1024         BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
1025                         ARRAY_SIZE(fw_device_attributes) +
1026                         ARRAY_SIZE(config_rom_attributes));
1027         init_fw_attribute_group(&device->device,
1028                                 fw_device_attributes,
1029                                 &device->attribute_group);
1030
1031         if (device_add(&device->device)) {
1032                 fw_err(card, "failed to add device\n");
1033                 goto error_with_cdev;
1034         }
1035
1036         create_units(device);
1037
1038         /*
1039          * Transition the device to running state.  If it got pulled
1040          * out from under us while we did the intialization work, we
1041          * have to shut down the device again here.  Normally, though,
1042          * fw_node_event will be responsible for shutting it down when
1043          * necessary.  We have to use the atomic cmpxchg here to avoid
1044          * racing with the FW_NODE_DESTROYED case in
1045          * fw_node_event().
1046          */
1047         if (atomic_cmpxchg(&device->state,
1048                            FW_DEVICE_INITIALIZING,
1049                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
1050                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1051                 fw_schedule_device_work(device, SHUTDOWN_DELAY);
1052         } else {
1053                 fw_notice(card, "created device %s: GUID %08x%08x, S%d00\n",
1054                           dev_name(&device->device),
1055                           device->config_rom[3], device->config_rom[4],
1056                           1 << device->max_speed);
1057                 device->config_rom_retries = 0;
1058
1059                 set_broadcast_channel(device, device->generation);
1060         }
1061
1062         /*
1063          * Reschedule the IRM work if we just finished reading the
1064          * root node config rom.  If this races with a bus reset we
1065          * just end up running the IRM work a couple of extra times -
1066          * pretty harmless.
1067          */
1068         if (device->node == card->root_node)
1069                 fw_schedule_bm_work(card, 0);
1070
1071         return;
1072
1073  error_with_cdev:
1074         down_write(&fw_device_rwsem);
1075         idr_remove(&fw_device_idr, minor);
1076         up_write(&fw_device_rwsem);
1077  error:
1078         fw_device_put(device);          /* fw_device_idr's reference */
1079
1080         put_device(&device->device);    /* our reference */
1081 }
1082
1083 /* Reread and compare bus info block and header of root directory */
1084 static int reread_config_rom(struct fw_device *device, int generation,
1085                              bool *changed)
1086 {
1087         u32 q;
1088         int i, rcode;
1089
1090         for (i = 0; i < 6; i++) {
1091                 rcode = read_rom(device, generation, i, &q);
1092                 if (rcode != RCODE_COMPLETE)
1093                         return rcode;
1094
1095                 if (i == 0 && q == 0)
1096                         /* inaccessible (see read_config_rom); retry later */
1097                         return RCODE_BUSY;
1098
1099                 if (q != device->config_rom[i]) {
1100                         *changed = true;
1101                         return RCODE_COMPLETE;
1102                 }
1103         }
1104
1105         *changed = false;
1106         return RCODE_COMPLETE;
1107 }
1108
1109 static void fw_device_refresh(struct work_struct *work)
1110 {
1111         struct fw_device *device =
1112                 container_of(work, struct fw_device, work.work);
1113         struct fw_card *card = device->card;
1114         int ret, node_id = device->node_id;
1115         bool changed;
1116
1117         ret = reread_config_rom(device, device->generation, &changed);
1118         if (ret != RCODE_COMPLETE)
1119                 goto failed_config_rom;
1120
1121         if (!changed) {
1122                 if (atomic_cmpxchg(&device->state,
1123                                    FW_DEVICE_INITIALIZING,
1124                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1125                         goto gone;
1126
1127                 fw_device_update(work);
1128                 device->config_rom_retries = 0;
1129                 goto out;
1130         }
1131
1132         /*
1133          * Something changed.  We keep things simple and don't investigate
1134          * further.  We just destroy all previous units and create new ones.
1135          */
1136         device_for_each_child(&device->device, NULL, shutdown_unit);
1137
1138         ret = read_config_rom(device, device->generation);
1139         if (ret != RCODE_COMPLETE)
1140                 goto failed_config_rom;
1141
1142         fw_device_cdev_update(device);
1143         create_units(device);
1144
1145         /* Userspace may want to re-read attributes. */
1146         kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1147
1148         if (atomic_cmpxchg(&device->state,
1149                            FW_DEVICE_INITIALIZING,
1150                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1151                 goto gone;
1152
1153         fw_notice(card, "refreshed device %s\n", dev_name(&device->device));
1154         device->config_rom_retries = 0;
1155         goto out;
1156
1157  failed_config_rom:
1158         if (device->config_rom_retries < MAX_RETRIES &&
1159             atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1160                 device->config_rom_retries++;
1161                 fw_schedule_device_work(device, RETRY_DELAY);
1162                 return;
1163         }
1164
1165         fw_notice(card, "giving up on refresh of device %s: %s\n",
1166                   dev_name(&device->device), fw_rcode_string(ret));
1167  gone:
1168         atomic_set(&device->state, FW_DEVICE_GONE);
1169         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1170         fw_schedule_device_work(device, SHUTDOWN_DELAY);
1171  out:
1172         if (node_id == card->root_node->node_id)
1173                 fw_schedule_bm_work(card, 0);
1174 }
1175
1176 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1177 {
1178         struct fw_device *device;
1179
1180         switch (event) {
1181         case FW_NODE_CREATED:
1182                 /*
1183                  * Attempt to scan the node, regardless whether its self ID has
1184                  * the L (link active) flag set or not.  Some broken devices
1185                  * send L=0 but have an up-and-running link; others send L=1
1186                  * without actually having a link.
1187                  */
1188  create:
1189                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
1190                 if (device == NULL)
1191                         break;
1192
1193                 /*
1194                  * Do minimal intialization of the device here, the
1195                  * rest will happen in fw_device_init().
1196                  *
1197                  * Attention:  A lot of things, even fw_device_get(),
1198                  * cannot be done before fw_device_init() finished!
1199                  * You can basically just check device->state and
1200                  * schedule work until then, but only while holding
1201                  * card->lock.
1202                  */
1203                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1204                 device->card = fw_card_get(card);
1205                 device->node = fw_node_get(node);
1206                 device->node_id = node->node_id;
1207                 device->generation = card->generation;
1208                 device->is_local = node == card->local_node;
1209                 mutex_init(&device->client_list_mutex);
1210                 INIT_LIST_HEAD(&device->client_list);
1211
1212                 /*
1213                  * Set the node data to point back to this device so
1214                  * FW_NODE_UPDATED callbacks can update the node_id
1215                  * and generation for the device.
1216                  */
1217                 node->data = device;
1218
1219                 /*
1220                  * Many devices are slow to respond after bus resets,
1221                  * especially if they are bus powered and go through
1222                  * power-up after getting plugged in.  We schedule the
1223                  * first config rom scan half a second after bus reset.
1224                  */
1225                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1226                 fw_schedule_device_work(device, INITIAL_DELAY);
1227                 break;
1228
1229         case FW_NODE_INITIATED_RESET:
1230         case FW_NODE_LINK_ON:
1231                 device = node->data;
1232                 if (device == NULL)
1233                         goto create;
1234
1235                 device->node_id = node->node_id;
1236                 smp_wmb();  /* update node_id before generation */
1237                 device->generation = card->generation;
1238                 if (atomic_cmpxchg(&device->state,
1239                             FW_DEVICE_RUNNING,
1240                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1241                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1242                         fw_schedule_device_work(device,
1243                                 device->is_local ? 0 : INITIAL_DELAY);
1244                 }
1245                 break;
1246
1247         case FW_NODE_UPDATED:
1248                 device = node->data;
1249                 if (device == NULL)
1250                         break;
1251
1252                 device->node_id = node->node_id;
1253                 smp_wmb();  /* update node_id before generation */
1254                 device->generation = card->generation;
1255                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1256                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1257                         fw_schedule_device_work(device, 0);
1258                 }
1259                 break;
1260
1261         case FW_NODE_DESTROYED:
1262         case FW_NODE_LINK_OFF:
1263                 if (!node->data)
1264                         break;
1265
1266                 /*
1267                  * Destroy the device associated with the node.  There
1268                  * are two cases here: either the device is fully
1269                  * initialized (FW_DEVICE_RUNNING) or we're in the
1270                  * process of reading its config rom
1271                  * (FW_DEVICE_INITIALIZING).  If it is fully
1272                  * initialized we can reuse device->work to schedule a
1273                  * full fw_device_shutdown().  If not, there's work
1274                  * scheduled to read it's config rom, and we just put
1275                  * the device in shutdown state to have that code fail
1276                  * to create the device.
1277                  */
1278                 device = node->data;
1279                 if (atomic_xchg(&device->state,
1280                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1281                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1282                         fw_schedule_device_work(device,
1283                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1284                 }
1285                 break;
1286         }
1287 }