drivers/firewire/fw-device.c

   1 /*
   2  * Device probing and sysfs code.
   3  *
   4  * Copyright (C) 2005-2006  Kristian Hoegsberg <krh@bitplanet.net>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 #include <linux/ctype.h>
  22 #include <linux/delay.h>
  23 #include <linux/device.h>
  24 #include <linux/errno.h>
  25 #include <linux/idr.h>
  26 #include <linux/jiffies.h>
  27 #include <linux/kobject.h>
  28 #include <linux/list.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/mutex.h>
  31 #include <linux/rwsem.h>
  32 #include <linux/semaphore.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/string.h>
  35 #include <linux/workqueue.h>
  36
  37 #include <asm/system.h>
  38
  39 #include "fw-device.h"
  40 #include "fw-topology.h"
  41 #include "fw-transaction.h"
  42
  43 void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
  44 {
  45         ci->p = p + 1;
  46         ci->end = ci->p + (p[0] >> 16);
  47 }
  48 EXPORT_SYMBOL(fw_csr_iterator_init);
  49
  50 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
  51 {
  52         *key = *ci->p >> 24;
  53         *value = *ci->p & 0xffffff;
  54
  55         return ci->p++ < ci->end;
  56 }
  57 EXPORT_SYMBOL(fw_csr_iterator_next);
  58
  59 static int is_fw_unit(struct device *dev);
  60
  61 static int match_unit_directory(u32 *directory, u32 match_flags,
  62                                 const struct ieee1394_device_id *id)
  63 {
  64         struct fw_csr_iterator ci;
  65         int key, value, match;
  66
  67         match = 0;
  68         fw_csr_iterator_init(&ci, directory);
  69         while (fw_csr_iterator_next(&ci, &key, &value)) {
  70                 if (key == CSR_VENDOR && value == id->vendor_id)
  71                         match |= IEEE1394_MATCH_VENDOR_ID;
  72                 if (key == CSR_MODEL && value == id->model_id)
  73                         match |= IEEE1394_MATCH_MODEL_ID;
  74                 if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
  75                         match |= IEEE1394_MATCH_SPECIFIER_ID;
  76                 if (key == CSR_VERSION && value == id->version)
  77                         match |= IEEE1394_MATCH_VERSION;
  78         }
  79
  80         return (match & match_flags) == match_flags;
  81 }
  82
  83 static int fw_unit_match(struct device *dev, struct device_driver *drv)
  84 {
  85         struct fw_unit *unit = fw_unit(dev);
  86         struct fw_device *device;
  87         const struct ieee1394_device_id *id;
  88
  89         /* We only allow binding to fw_units. */
  90         if (!is_fw_unit(dev))
  91                 return 0;
  92
  93         device = fw_device(unit->device.parent);
  94
  95         for (id = fw_driver(drv)->id_table; id->match_flags != 0; id++) {
  96                 if (match_unit_directory(unit->directory, id->match_flags, id))
  97                         return 1;
  98
  99                 /* Also check vendor ID in the root directory. */
 100                 if ((id->match_flags & IEEE1394_MATCH_VENDOR_ID) &&
 101                     match_unit_directory(&device->config_rom[5],
 102                                 IEEE1394_MATCH_VENDOR_ID, id) &&
 103                     match_unit_directory(unit->directory, id->match_flags
 104                                 & ~IEEE1394_MATCH_VENDOR_ID, id))
 105                         return 1;
 106         }
 107
 108         return 0;
 109 }
 110
 111 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
 112 {
 113         struct fw_device *device = fw_device(unit->device.parent);
 114         struct fw_csr_iterator ci;
 115
 116         int key, value;
 117         int vendor = 0;
 118         int model = 0;
 119         int specifier_id = 0;
 120         int version = 0;
 121
 122         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 123         while (fw_csr_iterator_next(&ci, &key, &value)) {
 124                 switch (key) {
 125                 case CSR_VENDOR:
 126                         vendor = value;
 127                         break;
 128                 case CSR_MODEL:
 129                         model = value;
 130                         break;
 131                 }
 132         }
 133
 134         fw_csr_iterator_init(&ci, unit->directory);
 135         while (fw_csr_iterator_next(&ci, &key, &value)) {
 136                 switch (key) {
 137                 case CSR_SPECIFIER_ID:
 138                         specifier_id = value;
 139                         break;
 140                 case CSR_VERSION:
 141                         version = value;
 142                         break;
 143                 }
 144         }
 145
 146         return snprintf(buffer, buffer_size,
 147                         "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
 148                         vendor, model, specifier_id, version);
 149 }
 150
 151 static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 152 {
 153         struct fw_unit *unit = fw_unit(dev);
 154         char modalias[64];
 155
 156         get_modalias(unit, modalias, sizeof(modalias));
 157
 158         if (add_uevent_var(env, "MODALIAS=%s", modalias))
 159                 return -ENOMEM;
 160
 161         return 0;
 162 }
 163
 164 struct bus_type fw_bus_type = {
 165         .name = "firewire",
 166         .match = fw_unit_match,
 167 };
 168 EXPORT_SYMBOL(fw_bus_type);
 169
 170 int fw_device_enable_phys_dma(struct fw_device *device)
 171 {
 172         int generation = device->generation;
 173
 174         /* device->node_id, accessed below, must not be older than generation */
 175         smp_rmb();
 176
 177         return device->card->driver->enable_phys_dma(device->card,
 178                                                      device->node_id,
 179                                                      generation);
 180 }
 181 EXPORT_SYMBOL(fw_device_enable_phys_dma);
 182
 183 struct config_rom_attribute {
 184         struct device_attribute attr;
 185         u32 key;
 186 };
 187
 188 static ssize_t show_immediate(struct device *dev,
 189                               struct device_attribute *dattr, char *buf)
 190 {
 191         struct config_rom_attribute *attr =
 192                 container_of(dattr, struct config_rom_attribute, attr);
 193         struct fw_csr_iterator ci;
 194         u32 *dir;
 195         int key, value, ret = -ENOENT;
 196
 197         down_read(&fw_device_rwsem);
 198
 199         if (is_fw_unit(dev))
 200                 dir = fw_unit(dev)->directory;
 201         else
 202                 dir = fw_device(dev)->config_rom + 5;
 203
 204         fw_csr_iterator_init(&ci, dir);
 205         while (fw_csr_iterator_next(&ci, &key, &value))
 206                 if (attr->key == key) {
 207                         ret = snprintf(buf, buf ? PAGE_SIZE : 0,
 208                                        "0x%06x\n", value);
 209                         break;
 210                 }
 211
 212         up_read(&fw_device_rwsem);
 213
 214         return ret;
 215 }
 216
 217 #define IMMEDIATE_ATTR(name, key)                               \
 218         { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
 219
 220 static ssize_t show_text_leaf(struct device *dev,
 221                               struct device_attribute *dattr, char *buf)
 222 {
 223         struct config_rom_attribute *attr =
 224                 container_of(dattr, struct config_rom_attribute, attr);
 225         struct fw_csr_iterator ci;
 226         u32 *dir, *block = NULL, *p, *end;
 227         int length, key, value, last_key = 0, ret = -ENOENT;
 228         char *b;
 229
 230         down_read(&fw_device_rwsem);
 231
 232         if (is_fw_unit(dev))
 233                 dir = fw_unit(dev)->directory;
 234         else
 235                 dir = fw_device(dev)->config_rom + 5;
 236
 237         fw_csr_iterator_init(&ci, dir);
 238         while (fw_csr_iterator_next(&ci, &key, &value)) {
 239                 if (attr->key == last_key &&
 240                     key == (CSR_DESCRIPTOR | CSR_LEAF))
 241                         block = ci.p - 1 + value;
 242                 last_key = key;
 243         }
 244
 245         if (block == NULL)
 246                 goto out;
 247
 248         length = min(block[0] >> 16, 256U);
 249         if (length < 3)
 250                 goto out;
 251
 252         if (block[1] != 0 || block[2] != 0)
 253                 /* Unknown encoding. */
 254                 goto out;
 255
 256         if (buf == NULL) {
 257                 ret = length * 4;
 258                 goto out;
 259         }
 260
 261         b = buf;
 262         end = &block[length + 1];
 263         for (p = &block[3]; p < end; p++, b += 4)
 264                 * (u32 *) b = (__force u32) __cpu_to_be32(*p);
 265
 266         /* Strip trailing whitespace and add newline. */
 267         while (b--, (isspace(*b) || *b == '\0') && b > buf);
 268         strcpy(b + 1, "\n");
 269         ret = b + 2 - buf;
 270  out:
 271         up_read(&fw_device_rwsem);
 272
 273         return ret;
 274 }
 275
 276 #define TEXT_LEAF_ATTR(name, key)                               \
 277         { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
 278
 279 static struct config_rom_attribute config_rom_attributes[] = {
 280         IMMEDIATE_ATTR(vendor, CSR_VENDOR),
 281         IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
 282         IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
 283         IMMEDIATE_ATTR(version, CSR_VERSION),
 284         IMMEDIATE_ATTR(model, CSR_MODEL),
 285         TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
 286         TEXT_LEAF_ATTR(model_name, CSR_MODEL),
 287         TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
 288 };
 289
 290 static void init_fw_attribute_group(struct device *dev,
 291                                     struct device_attribute *attrs,
 292                                     struct fw_attribute_group *group)
 293 {
 294         struct device_attribute *attr;
 295         int i, j;
 296
 297         for (j = 0; attrs[j].attr.name != NULL; j++)
 298                 group->attrs[j] = &attrs[j].attr;
 299
 300         for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
 301                 attr = &config_rom_attributes[i].attr;
 302                 if (attr->show(dev, attr, NULL) < 0)
 303                         continue;
 304                 group->attrs[j++] = &attr->attr;
 305         }
 306
 307         group->attrs[j] = NULL;
 308         group->groups[0] = &group->group;
 309         group->groups[1] = NULL;
 310         group->group.attrs = group->attrs;
 311         dev->groups = group->groups;
 312 }
 313
 314 static ssize_t modalias_show(struct device *dev,
 315                              struct device_attribute *attr, char *buf)
 316 {
 317         struct fw_unit *unit = fw_unit(dev);
 318         int length;
 319
 320         length = get_modalias(unit, buf, PAGE_SIZE);
 321         strcpy(buf + length, "\n");
 322
 323         return length + 1;
 324 }
 325
 326 static ssize_t rom_index_show(struct device *dev,
 327                               struct device_attribute *attr, char *buf)
 328 {
 329         struct fw_device *device = fw_device(dev->parent);
 330         struct fw_unit *unit = fw_unit(dev);
 331
 332         return snprintf(buf, PAGE_SIZE, "%d\n",
 333                         (int)(unit->directory - device->config_rom));
 334 }
 335
 336 static struct device_attribute fw_unit_attributes[] = {
 337         __ATTR_RO(modalias),
 338         __ATTR_RO(rom_index),
 339         __ATTR_NULL,
 340 };
 341
 342 static ssize_t config_rom_show(struct device *dev,
 343                                struct device_attribute *attr, char *buf)
 344 {
 345         struct fw_device *device = fw_device(dev);
 346         size_t length;
 347
 348         down_read(&fw_device_rwsem);
 349         length = device->config_rom_length * 4;
 350         memcpy(buf, device->config_rom, length);
 351         up_read(&fw_device_rwsem);
 352
 353         return length;
 354 }
 355
 356 static ssize_t guid_show(struct device *dev,
 357                          struct device_attribute *attr, char *buf)
 358 {
 359         struct fw_device *device = fw_device(dev);
 360         int ret;
 361
 362         down_read(&fw_device_rwsem);
 363         ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
 364                        device->config_rom[3], device->config_rom[4]);
 365         up_read(&fw_device_rwsem);
 366
 367         return ret;
 368 }
 369
 370 static int units_sprintf(char *buf, u32 *directory)
 371 {
 372         struct fw_csr_iterator ci;
 373         int key, value;
 374         int specifier_id = 0;
 375         int version = 0;
 376
 377         fw_csr_iterator_init(&ci, directory);
 378         while (fw_csr_iterator_next(&ci, &key, &value)) {
 379                 switch (key) {
 380                 case CSR_SPECIFIER_ID:
 381                         specifier_id = value;
 382                         break;
 383                 case CSR_VERSION:
 384                         version = value;
 385                         break;
 386                 }
 387         }
 388
 389         return sprintf(buf, "0x%06x:0x%06x ", specifier_id, version);
 390 }
 391
 392 static ssize_t units_show(struct device *dev,
 393                           struct device_attribute *attr, char *buf)
 394 {
 395         struct fw_device *device = fw_device(dev);
 396         struct fw_csr_iterator ci;
 397         int key, value, i = 0;
 398
 399         down_read(&fw_device_rwsem);
 400         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 401         while (fw_csr_iterator_next(&ci, &key, &value)) {
 402                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 403                         continue;
 404                 i += units_sprintf(&buf[i], ci.p + value - 1);
 405                 if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
 406                         break;
 407         }
 408         up_read(&fw_device_rwsem);
 409
 410         if (i)
 411                 buf[i - 1] = '\n';
 412
 413         return i;
 414 }
 415
 416 static struct device_attribute fw_device_attributes[] = {
 417         __ATTR_RO(config_rom),
 418         __ATTR_RO(guid),
 419         __ATTR_RO(units),
 420         __ATTR_NULL,
 421 };
 422
 423 static int read_rom(struct fw_device *device,
 424                     int generation, int index, u32 *data)
 425 {
 426         int rcode;
 427
 428         /* device->node_id, accessed below, must not be older than generation */
 429         smp_rmb();
 430
 431         rcode = fw_run_transaction(device->card, TCODE_READ_QUADLET_REQUEST,
 432                         device->node_id, generation, device->max_speed,
 433                         (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4,
 434                         data, 4);
 435         be32_to_cpus(data);
 436
 437         return rcode;
 438 }
 439
 440 #define READ_BIB_ROM_SIZE       256
 441 #define READ_BIB_STACK_SIZE     16
 442
 443 /*
 444  * Read the bus info block, perform a speed probe, and read all of the rest of
 445  * the config ROM.  We do all this with a cached bus generation.  If the bus
 446  * generation changes under us, read_bus_info_block will fail and get retried.
 447  * It's better to start all over in this case because the node from which we
 448  * are reading the ROM may have changed the ROM during the reset.
 449  */
 450 static int read_bus_info_block(struct fw_device *device, int generation)
 451 {
 452         u32 *rom, *stack, *old_rom, *new_rom;
 453         u32 sp, key;
 454         int i, end, length, ret = -1;
 455
 456         rom = kmalloc(sizeof(*rom) * READ_BIB_ROM_SIZE +
 457                       sizeof(*stack) * READ_BIB_STACK_SIZE, GFP_KERNEL);
 458         if (rom == NULL)
 459                 return -ENOMEM;
 460
 461         stack = &rom[READ_BIB_ROM_SIZE];
 462
 463         device->max_speed = SCODE_100;
 464
 465         /* First read the bus info block. */
 466         for (i = 0; i < 5; i++) {
 467                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 468                         goto out;
 469                 /*
 470                  * As per IEEE1212 7.2, during power-up, devices can
 471                  * reply with a 0 for the first quadlet of the config
 472                  * rom to indicate that they are booting (for example,
 473                  * if the firmware is on the disk of a external
 474                  * harddisk).  In that case we just fail, and the
 475                  * retry mechanism will try again later.
 476                  */
 477                 if (i == 0 && rom[i] == 0)
 478                         goto out;
 479         }
 480
 481         device->max_speed = device->node->max_speed;
 482
 483         /*
 484          * Determine the speed of
 485          *   - devices with link speed less than PHY speed,
 486          *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
 487          *   - all devices if there are 1394b repeaters.
 488          * Note, we cannot use the bus info block's link_spd as starting point
 489          * because some buggy firmwares set it lower than necessary and because
 490          * 1394-1995 nodes do not have the field.
 491          */
 492         if ((rom[2] & 0x7) < device->max_speed ||
 493             device->max_speed == SCODE_BETA ||
 494             device->card->beta_repeaters_present) {
 495                 u32 dummy;
 496
 497                 /* for S1600 and S3200 */
 498                 if (device->max_speed == SCODE_BETA)
 499                         device->max_speed = device->card->link_speed;
 500
 501                 while (device->max_speed > SCODE_100) {
 502                         if (read_rom(device, generation, 0, &dummy) ==
 503                             RCODE_COMPLETE)
 504                                 break;
 505                         device->max_speed--;
 506                 }
 507         }
 508
 509         /*
 510          * Now parse the config rom.  The config rom is a recursive
 511          * directory structure so we parse it using a stack of
 512          * references to the blocks that make up the structure.  We
 513          * push a reference to the root directory on the stack to
 514          * start things off.
 515          */
 516         length = i;
 517         sp = 0;
 518         stack[sp++] = 0xc0000005;
 519         while (sp > 0) {
 520                 /*
 521                  * Pop the next block reference of the stack.  The
 522                  * lower 24 bits is the offset into the config rom,
 523                  * the upper 8 bits are the type of the reference the
 524                  * block.
 525                  */
 526                 key = stack[--sp];
 527                 i = key & 0xffffff;
 528                 if (i >= READ_BIB_ROM_SIZE)
 529                         /*
 530                          * The reference points outside the standard
 531                          * config rom area, something's fishy.
 532                          */
 533                         goto out;
 534
 535                 /* Read header quadlet for the block to get the length. */
 536                 if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 537                         goto out;
 538                 end = i + (rom[i] >> 16) + 1;
 539                 i++;
 540                 if (end > READ_BIB_ROM_SIZE)
 541                         /*
 542                          * This block extends outside standard config
 543                          * area (and the array we're reading it
 544                          * into).  That's broken, so ignore this
 545                          * device.
 546                          */
 547                         goto out;
 548
 549                 /*
 550                  * Now read in the block.  If this is a directory
 551                  * block, check the entries as we read them to see if
 552                  * it references another block, and push it in that case.
 553                  */
 554                 while (i < end) {
 555                         if (read_rom(device, generation, i, &rom[i]) !=
 556                             RCODE_COMPLETE)
 557                                 goto out;
 558                         if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
 559                             sp < READ_BIB_STACK_SIZE)
 560                                 stack[sp++] = i + rom[i];
 561                         i++;
 562                 }
 563                 if (length < i)
 564                         length = i;
 565         }
 566
 567         old_rom = device->config_rom;
 568         new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
 569         if (new_rom == NULL)
 570                 goto out;
 571
 572         down_write(&fw_device_rwsem);
 573         device->config_rom = new_rom;
 574         device->config_rom_length = length;
 575         up_write(&fw_device_rwsem);
 576
 577         kfree(old_rom);
 578         ret = 0;
 579         device->cmc = rom[2] >> 30 & 1;
 580  out:
 581         kfree(rom);
 582
 583         return ret;
 584 }
 585
 586 static void fw_unit_release(struct device *dev)
 587 {
 588         struct fw_unit *unit = fw_unit(dev);
 589
 590         kfree(unit);
 591 }
 592
 593 static struct device_type fw_unit_type = {
 594         .uevent         = fw_unit_uevent,
 595         .release        = fw_unit_release,
 596 };
 597
 598 static int is_fw_unit(struct device *dev)
 599 {
 600         return dev->type == &fw_unit_type;
 601 }
 602
 603 static void create_units(struct fw_device *device)
 604 {
 605         struct fw_csr_iterator ci;
 606         struct fw_unit *unit;
 607         int key, value, i;
 608
 609         i = 0;
 610         fw_csr_iterator_init(&ci, &device->config_rom[5]);
 611         while (fw_csr_iterator_next(&ci, &key, &value)) {
 612                 if (key != (CSR_UNIT | CSR_DIRECTORY))
 613                         continue;
 614
 615                 /*
 616                  * Get the address of the unit directory and try to
 617                  * match the drivers id_tables against it.
 618                  */
 619                 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 620                 if (unit == NULL) {
 621                         fw_error("failed to allocate memory for unit\n");
 622                         continue;
 623                 }
 624
 625                 unit->directory = ci.p + value - 1;
 626                 unit->device.bus = &fw_bus_type;
 627                 unit->device.type = &fw_unit_type;
 628                 unit->device.parent = &device->device;
 629                 dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
 630
 631                 BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
 632                                 ARRAY_SIZE(fw_unit_attributes) +
 633                                 ARRAY_SIZE(config_rom_attributes));
 634                 init_fw_attribute_group(&unit->device,
 635                                         fw_unit_attributes,
 636                                         &unit->attribute_group);
 637
 638                 if (device_register(&unit->device) < 0)
 639                         goto skip_unit;
 640
 641                 continue;
 642
 643         skip_unit:
 644                 kfree(unit);
 645         }
 646 }
 647
 648 static int shutdown_unit(struct device *device, void *data)
 649 {
 650         device_unregister(device);
 651
 652         return 0;
 653 }
 654
 655 /*
 656  * fw_device_rwsem acts as dual purpose mutex:
 657  *   - serializes accesses to fw_device_idr,
 658  *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 659  *     fw_unit.directory, unless those accesses happen at safe occasions
 660  */
 661 DECLARE_RWSEM(fw_device_rwsem);
 662
 663 DEFINE_IDR(fw_device_idr);
 664 int fw_cdev_major;
 665
 666 struct fw_device *fw_device_get_by_devt(dev_t devt)
 667 {
 668         struct fw_device *device;
 669
 670         down_read(&fw_device_rwsem);
 671         device = idr_find(&fw_device_idr, MINOR(devt));
 672         if (device)
 673                 fw_device_get(device);
 674         up_read(&fw_device_rwsem);
 675
 676         return device;
 677 }
 678
 679 /*
 680  * These defines control the retry behavior for reading the config
 681  * rom.  It shouldn't be necessary to tweak these; if the device
 682  * doesn't respond to a config rom read within 10 seconds, it's not
 683  * going to respond at all.  As for the initial delay, a lot of
 684  * devices will be able to respond within half a second after bus
 685  * reset.  On the other hand, it's not really worth being more
 686  * aggressive than that, since it scales pretty well; if 10 devices
 687  * are plugged in, they're all getting read within one second.
 688  */
 689
 690 #define MAX_RETRIES     10
 691 #define RETRY_DELAY     (3 * HZ)
 692 #define INITIAL_DELAY   (HZ / 2)
 693 #define SHUTDOWN_DELAY  (2 * HZ)
 694
 695 static void fw_device_shutdown(struct work_struct *work)
 696 {
 697         struct fw_device *device =
 698                 container_of(work, struct fw_device, work.work);
 699         int minor = MINOR(device->device.devt);
 700
 701         if (time_is_after_jiffies(device->card->reset_jiffies + SHUTDOWN_DELAY)
 702             && !list_empty(&device->card->link)) {
 703                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 704                 return;
 705         }
 706
 707         if (atomic_cmpxchg(&device->state,
 708                            FW_DEVICE_GONE,
 709                            FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
 710                 return;
 711
 712         fw_device_cdev_remove(device);
 713         device_for_each_child(&device->device, NULL, shutdown_unit);
 714         device_unregister(&device->device);
 715
 716         down_write(&fw_device_rwsem);
 717         idr_remove(&fw_device_idr, minor);
 718         up_write(&fw_device_rwsem);
 719
 720         fw_device_put(device);
 721 }
 722
 723 static void fw_device_release(struct device *dev)
 724 {
 725         struct fw_device *device = fw_device(dev);
 726         struct fw_card *card = device->card;
 727         unsigned long flags;
 728
 729         /*
 730          * Take the card lock so we don't set this to NULL while a
 731          * FW_NODE_UPDATED callback is being handled or while the
 732          * bus manager work looks at this node.
 733          */
 734         spin_lock_irqsave(&card->lock, flags);
 735         device->node->data = NULL;
 736         spin_unlock_irqrestore(&card->lock, flags);
 737
 738         fw_node_put(device->node);
 739         kfree(device->config_rom);
 740         kfree(device);
 741         fw_card_put(card);
 742 }
 743
 744 static struct device_type fw_device_type = {
 745         .release = fw_device_release,
 746 };
 747
 748 static int update_unit(struct device *dev, void *data)
 749 {
 750         struct fw_unit *unit = fw_unit(dev);
 751         struct fw_driver *driver = (struct fw_driver *)dev->driver;
 752
 753         if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
 754                 down(&dev->sem);
 755                 driver->update(unit);
 756                 up(&dev->sem);
 757         }
 758
 759         return 0;
 760 }
 761
 762 static void fw_device_update(struct work_struct *work)
 763 {
 764         struct fw_device *device =
 765                 container_of(work, struct fw_device, work.work);
 766
 767         fw_device_cdev_update(device);
 768         device_for_each_child(&device->device, NULL, update_unit);
 769 }
 770
 771 /*
 772  * If a device was pending for deletion because its node went away but its
 773  * bus info block and root directory header matches that of a newly discovered
 774  * device, revive the existing fw_device.
 775  * The newly allocated fw_device becomes obsolete instead.
 776  */
 777 static int lookup_existing_device(struct device *dev, void *data)
 778 {
 779         struct fw_device *old = fw_device(dev);
 780         struct fw_device *new = data;
 781         struct fw_card *card = new->card;
 782         int match = 0;
 783
 784         down_read(&fw_device_rwsem); /* serialize config_rom access */
 785         spin_lock_irq(&card->lock);  /* serialize node access */
 786
 787         if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
 788             atomic_cmpxchg(&old->state,
 789                            FW_DEVICE_GONE,
 790                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 791                 struct fw_node *current_node = new->node;
 792                 struct fw_node *obsolete_node = old->node;
 793
 794                 new->node = obsolete_node;
 795                 new->node->data = new;
 796                 old->node = current_node;
 797                 old->node->data = old;
 798
 799                 old->max_speed = new->max_speed;
 800                 old->node_id = current_node->node_id;
 801                 smp_wmb();  /* update node_id before generation */
 802                 old->generation = card->generation;
 803                 old->config_rom_retries = 0;
 804                 fw_notify("rediscovered device %s\n", dev_name(dev));
 805
 806                 PREPARE_DELAYED_WORK(&old->work, fw_device_update);
 807                 schedule_delayed_work(&old->work, 0);
 808
 809                 if (current_node == card->root_node)
 810                         fw_schedule_bm_work(card, 0);
 811
 812                 match = 1;
 813         }
 814
 815         spin_unlock_irq(&card->lock);
 816         up_read(&fw_device_rwsem);
 817
 818         return match;
 819 }
 820
 821 enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
 822
 823 void fw_device_set_broadcast_channel(struct fw_device *device, int generation)
 824 {
 825         struct fw_card *card = device->card;
 826         __be32 data;
 827         int rcode;
 828
 829         if (!card->broadcast_channel_allocated)
 830                 return;
 831
 832         if (device->bc_implemented == BC_UNKNOWN) {
 833                 rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
 834                                 device->node_id, generation, device->max_speed,
 835                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 836                                 &data, 4);
 837                 switch (rcode) {
 838                 case RCODE_COMPLETE:
 839                         if (data & cpu_to_be32(1 << 31)) {
 840                                 device->bc_implemented = BC_IMPLEMENTED;
 841                                 break;
 842                         }
 843                         /* else fall through to case address error */
 844                 case RCODE_ADDRESS_ERROR:
 845                         device->bc_implemented = BC_UNIMPLEMENTED;
 846                 }
 847         }
 848
 849         if (device->bc_implemented == BC_IMPLEMENTED) {
 850                 data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
 851                                    BROADCAST_CHANNEL_VALID);
 852                 fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
 853                                 device->node_id, generation, device->max_speed,
 854                                 CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 855                                 &data, 4);
 856         }
 857 }
 858
 859 static void fw_device_init(struct work_struct *work)
 860 {
 861         struct fw_device *device =
 862                 container_of(work, struct fw_device, work.work);
 863         struct device *revived_dev;
 864         int minor, ret;
 865
 866         /*
 867          * All failure paths here set node->data to NULL, so that we
 868          * don't try to do device_for_each_child() on a kfree()'d
 869          * device.
 870          */
 871
 872         if (read_bus_info_block(device, device->generation) < 0) {
 873                 if (device->config_rom_retries < MAX_RETRIES &&
 874                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 875                         device->config_rom_retries++;
 876                         schedule_delayed_work(&device->work, RETRY_DELAY);
 877                 } else {
 878                         fw_notify("giving up on config rom for node id %x\n",
 879                                   device->node_id);
 880                         if (device->node == device->card->root_node)
 881                                 fw_schedule_bm_work(device->card, 0);
 882                         fw_device_release(&device->device);
 883                 }
 884                 return;
 885         }
 886
 887         revived_dev = device_find_child(device->card->device,
 888                                         device, lookup_existing_device);
 889         if (revived_dev) {
 890                 put_device(revived_dev);
 891                 fw_device_release(&device->device);
 892
 893                 return;
 894         }
 895
 896         device_initialize(&device->device);
 897
 898         fw_device_get(device);
 899         down_write(&fw_device_rwsem);
 900         ret = idr_pre_get(&fw_device_idr, GFP_KERNEL) ?
 901               idr_get_new(&fw_device_idr, device, &minor) :
 902               -ENOMEM;
 903         up_write(&fw_device_rwsem);
 904
 905         if (ret < 0)
 906                 goto error;
 907
 908         device->device.bus = &fw_bus_type;
 909         device->device.type = &fw_device_type;
 910         device->device.parent = device->card->device;
 911         device->device.devt = MKDEV(fw_cdev_major, minor);
 912         dev_set_name(&device->device, "fw%d", minor);
 913
 914         BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
 915                         ARRAY_SIZE(fw_device_attributes) +
 916                         ARRAY_SIZE(config_rom_attributes));
 917         init_fw_attribute_group(&device->device,
 918                                 fw_device_attributes,
 919                                 &device->attribute_group);
 920
 921         if (device_add(&device->device)) {
 922                 fw_error("Failed to add device.\n");
 923                 goto error_with_cdev;
 924         }
 925
 926         create_units(device);
 927
 928         /*
 929          * Transition the device to running state.  If it got pulled
 930          * out from under us while we did the intialization work, we
 931          * have to shut down the device again here.  Normally, though,
 932          * fw_node_event will be responsible for shutting it down when
 933          * necessary.  We have to use the atomic cmpxchg here to avoid
 934          * racing with the FW_NODE_DESTROYED case in
 935          * fw_node_event().
 936          */
 937         if (atomic_cmpxchg(&device->state,
 938                            FW_DEVICE_INITIALIZING,
 939                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 940                 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
 941                 schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
 942         } else {
 943                 if (device->config_rom_retries)
 944                         fw_notify("created device %s: GUID %08x%08x, S%d00, "
 945                                   "%d config ROM retries\n",
 946                                   dev_name(&device->device),
 947                                   device->config_rom[3], device->config_rom[4],
 948                                   1 << device->max_speed,
 949                                   device->config_rom_retries);
 950                 else
 951                         fw_notify("created device %s: GUID %08x%08x, S%d00\n",
 952                                   dev_name(&device->device),
 953                                   device->config_rom[3], device->config_rom[4],
 954                                   1 << device->max_speed);
 955                 device->config_rom_retries = 0;
 956
 957                 fw_device_set_broadcast_channel(device, device->generation);
 958         }
 959
 960         /*
 961          * Reschedule the IRM work if we just finished reading the
 962          * root node config rom.  If this races with a bus reset we
 963          * just end up running the IRM work a couple of extra times -
 964          * pretty harmless.
 965          */
 966         if (device->node == device->card->root_node)
 967                 fw_schedule_bm_work(device->card, 0);
 968
 969         return;
 970
 971  error_with_cdev:
 972         down_write(&fw_device_rwsem);
 973         idr_remove(&fw_device_idr, minor);
 974         up_write(&fw_device_rwsem);
 975  error:
 976         fw_device_put(device);          /* fw_device_idr's reference */
 977
 978         put_device(&device->device);    /* our reference */
 979 }
 980
 981 enum {
 982         REREAD_BIB_ERROR,
 983         REREAD_BIB_GONE,
 984         REREAD_BIB_UNCHANGED,
 985         REREAD_BIB_CHANGED,
 986 };
 987
 988 /* Reread and compare bus info block and header of root directory */
 989 static int reread_bus_info_block(struct fw_device *device, int generation)
 990 {
 991         u32 q;
 992         int i;
 993
 994         for (i = 0; i < 6; i++) {
 995                 if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
 996                         return REREAD_BIB_ERROR;
 997
 998                 if (i == 0 && q == 0)
 999                         return REREAD_BIB_GONE;
1000
1001                 if (q != device->config_rom[i])
1002                         return REREAD_BIB_CHANGED;
1003         }
1004
1005         return REREAD_BIB_UNCHANGED;
1006 }
1007
1008 static void fw_device_refresh(struct work_struct *work)
1009 {
1010         struct fw_device *device =
1011                 container_of(work, struct fw_device, work.work);
1012         struct fw_card *card = device->card;
1013         int node_id = device->node_id;
1014
1015         switch (reread_bus_info_block(device, device->generation)) {
1016         case REREAD_BIB_ERROR:
1017                 if (device->config_rom_retries < MAX_RETRIES / 2 &&
1018                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1019                         device->config_rom_retries++;
1020                         schedule_delayed_work(&device->work, RETRY_DELAY / 2);
1021
1022                         return;
1023                 }
1024                 goto give_up;
1025
1026         case REREAD_BIB_GONE:
1027                 goto gone;
1028
1029         case REREAD_BIB_UNCHANGED:
1030                 if (atomic_cmpxchg(&device->state,
1031                                    FW_DEVICE_INITIALIZING,
1032                                    FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1033                         goto gone;
1034
1035                 fw_device_update(work);
1036                 device->config_rom_retries = 0;
1037                 goto out;
1038
1039         case REREAD_BIB_CHANGED:
1040                 break;
1041         }
1042
1043         /*
1044          * Something changed.  We keep things simple and don't investigate
1045          * further.  We just destroy all previous units and create new ones.
1046          */
1047         device_for_each_child(&device->device, NULL, shutdown_unit);
1048
1049         if (read_bus_info_block(device, device->generation) < 0) {
1050                 if (device->config_rom_retries < MAX_RETRIES &&
1051                     atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1052                         device->config_rom_retries++;
1053                         schedule_delayed_work(&device->work, RETRY_DELAY);
1054
1055                         return;
1056                 }
1057                 goto give_up;
1058         }
1059
1060         create_units(device);
1061
1062         /* Userspace may want to re-read attributes. */
1063         kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1064
1065         if (atomic_cmpxchg(&device->state,
1066                            FW_DEVICE_INITIALIZING,
1067                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1068                 goto gone;
1069
1070         fw_notify("refreshed device %s\n", dev_name(&device->device));
1071         device->config_rom_retries = 0;
1072         goto out;
1073
1074  give_up:
1075         fw_notify("giving up on refresh of device %s\n", dev_name(&device->device));
1076  gone:
1077         atomic_set(&device->state, FW_DEVICE_GONE);
1078         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1079         schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
1080  out:
1081         if (node_id == card->root_node->node_id)
1082                 fw_schedule_bm_work(card, 0);
1083 }
1084
1085 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1086 {
1087         struct fw_device *device;
1088
1089         switch (event) {
1090         case FW_NODE_CREATED:
1091         case FW_NODE_LINK_ON:
1092                 if (!node->link_on)
1093                         break;
1094  create:
1095                 device = kzalloc(sizeof(*device), GFP_ATOMIC);
1096                 if (device == NULL)
1097                         break;
1098
1099                 /*
1100                  * Do minimal intialization of the device here, the
1101                  * rest will happen in fw_device_init().
1102                  *
1103                  * Attention:  A lot of things, even fw_device_get(),
1104                  * cannot be done before fw_device_init() finished!
1105                  * You can basically just check device->state and
1106                  * schedule work until then, but only while holding
1107                  * card->lock.
1108                  */
1109                 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1110                 device->card = fw_card_get(card);
1111                 device->node = fw_node_get(node);
1112                 device->node_id = node->node_id;
1113                 device->generation = card->generation;
1114                 device->is_local = node == card->local_node;
1115                 mutex_init(&device->client_list_mutex);
1116                 INIT_LIST_HEAD(&device->client_list);
1117
1118                 /*
1119                  * Set the node data to point back to this device so
1120                  * FW_NODE_UPDATED callbacks can update the node_id
1121                  * and generation for the device.
1122                  */
1123                 node->data = device;
1124
1125                 /*
1126                  * Many devices are slow to respond after bus resets,
1127                  * especially if they are bus powered and go through
1128                  * power-up after getting plugged in.  We schedule the
1129                  * first config rom scan half a second after bus reset.
1130                  */
1131                 INIT_DELAYED_WORK(&device->work, fw_device_init);
1132                 schedule_delayed_work(&device->work, INITIAL_DELAY);
1133                 break;
1134
1135         case FW_NODE_INITIATED_RESET:
1136                 device = node->data;
1137                 if (device == NULL)
1138                         goto create;
1139
1140                 device->node_id = node->node_id;
1141                 smp_wmb();  /* update node_id before generation */
1142                 device->generation = card->generation;
1143                 if (atomic_cmpxchg(&device->state,
1144                             FW_DEVICE_RUNNING,
1145                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1146                         PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1147                         schedule_delayed_work(&device->work,
1148                                 device->is_local ? 0 : INITIAL_DELAY);
1149                 }
1150                 break;
1151
1152         case FW_NODE_UPDATED:
1153                 if (!node->link_on || node->data == NULL)
1154                         break;
1155
1156                 device = node->data;
1157                 device->node_id = node->node_id;
1158                 smp_wmb();  /* update node_id before generation */
1159                 device->generation = card->generation;
1160                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1161                         PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1162                         schedule_delayed_work(&device->work, 0);
1163                 }
1164                 break;
1165
1166         case FW_NODE_DESTROYED:
1167         case FW_NODE_LINK_OFF:
1168                 if (!node->data)
1169                         break;
1170
1171                 /*
1172                  * Destroy the device associated with the node.  There
1173                  * are two cases here: either the device is fully
1174                  * initialized (FW_DEVICE_RUNNING) or we're in the
1175                  * process of reading its config rom
1176                  * (FW_DEVICE_INITIALIZING).  If it is fully
1177                  * initialized we can reuse device->work to schedule a
1178                  * full fw_device_shutdown().  If not, there's work
1179                  * scheduled to read it's config rom, and we just put
1180                  * the device in shutdown state to have that code fail
1181                  * to create the device.
1182                  */
1183                 device = node->data;
1184                 if (atomic_xchg(&device->state,
1185                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1186                         PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1187                         schedule_delayed_work(&device->work,
1188                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1189                 }
1190                 break;
1191         }
1192 }