linux/drivers/firewire/core-device.c
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   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/random.h>
  36#include <linux/rwsem.h>
  37#include <linux/slab.h>
  38#include <linux/spinlock.h>
  39#include <linux/string.h>
  40#include <linux/workqueue.h>
  41
  42#include <linux/atomic.h>
  43#include <asm/byteorder.h>
  44
  45#include "core.h"
  46
  47void fw_csr_iterator_init(struct fw_csr_iterator *ci, const u32 *p)
  48{
  49        ci->p = p + 1;
  50        ci->end = ci->p + (p[0] >> 16);
  51}
  52EXPORT_SYMBOL(fw_csr_iterator_init);
  53
  54int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
  55{
  56        *key = *ci->p >> 24;
  57        *value = *ci->p & 0xffffff;
  58
  59        return ci->p++ < ci->end;
  60}
  61EXPORT_SYMBOL(fw_csr_iterator_next);
  62
  63static const u32 *search_leaf(const u32 *directory, int search_key)
  64{
  65        struct fw_csr_iterator ci;
  66        int last_key = 0, key, value;
  67
  68        fw_csr_iterator_init(&ci, directory);
  69        while (fw_csr_iterator_next(&ci, &key, &value)) {
  70                if (last_key == search_key &&
  71                    key == (CSR_DESCRIPTOR | CSR_LEAF))
  72                        return ci.p - 1 + value;
  73
  74                last_key = key;
  75        }
  76
  77        return NULL;
  78}
  79
  80static int textual_leaf_to_string(const u32 *block, char *buf, size_t size)
  81{
  82        unsigned int quadlets, i;
  83        char c;
  84
  85        if (!size || !buf)
  86                return -EINVAL;
  87
  88        quadlets = min(block[0] >> 16, 256U);
  89        if (quadlets < 2)
  90                return -ENODATA;
  91
  92        if (block[1] != 0 || block[2] != 0)
  93                /* unknown language/character set */
  94                return -ENODATA;
  95
  96        block += 3;
  97        quadlets -= 2;
  98        for (i = 0; i < quadlets * 4 && i < size - 1; i++) {
  99                c = block[i / 4] >> (24 - 8 * (i % 4));
 100                if (c == '\0')
 101                        break;
 102                buf[i] = c;
 103        }
 104        buf[i] = '\0';
 105
 106        return i;
 107}
 108
 109/**
 110 * fw_csr_string() - reads a string from the configuration ROM
 111 * @directory:  e.g. root directory or unit directory
 112 * @key:        the key of the preceding directory entry
 113 * @buf:        where to put the string
 114 * @size:       size of @buf, in bytes
 115 *
 116 * The string is taken from a minimal ASCII text descriptor leaf after
 117 * the immediate entry with @key.  The string is zero-terminated.
 118 * Returns strlen(buf) or a negative error code.
 119 */
 120int fw_csr_string(const u32 *directory, int key, char *buf, size_t size)
 121{
 122        const u32 *leaf = search_leaf(directory, key);
 123        if (!leaf)
 124                return -ENOENT;
 125
 126        return textual_leaf_to_string(leaf, buf, size);
 127}
 128EXPORT_SYMBOL(fw_csr_string);
 129
 130static void get_ids(const u32 *directory, int *id)
 131{
 132        struct fw_csr_iterator ci;
 133        int key, value;
 134
 135        fw_csr_iterator_init(&ci, directory);
 136        while (fw_csr_iterator_next(&ci, &key, &value)) {
 137                switch (key) {
 138                case CSR_VENDOR:        id[0] = value; break;
 139                case CSR_MODEL:         id[1] = value; break;
 140                case CSR_SPECIFIER_ID:  id[2] = value; break;
 141                case CSR_VERSION:       id[3] = value; break;
 142                }
 143        }
 144}
 145
 146static void get_modalias_ids(struct fw_unit *unit, int *id)
 147{
 148        get_ids(&fw_parent_device(unit)->config_rom[5], id);
 149        get_ids(unit->directory, id);
 150}
 151
 152static bool match_ids(const struct ieee1394_device_id *id_table, int *id)
 153{
 154        int match = 0;
 155
 156        if (id[0] == id_table->vendor_id)
 157                match |= IEEE1394_MATCH_VENDOR_ID;
 158        if (id[1] == id_table->model_id)
 159                match |= IEEE1394_MATCH_MODEL_ID;
 160        if (id[2] == id_table->specifier_id)
 161                match |= IEEE1394_MATCH_SPECIFIER_ID;
 162        if (id[3] == id_table->version)
 163                match |= IEEE1394_MATCH_VERSION;
 164
 165        return (match & id_table->match_flags) == id_table->match_flags;
 166}
 167
 168static bool is_fw_unit(struct device *dev);
 169
 170static int fw_unit_match(struct device *dev, struct device_driver *drv)
 171{
 172        const struct ieee1394_device_id *id_table =
 173                        container_of(drv, struct fw_driver, driver)->id_table;
 174        int id[] = {0, 0, 0, 0};
 175
 176        /* We only allow binding to fw_units. */
 177        if (!is_fw_unit(dev))
 178                return 0;
 179
 180        get_modalias_ids(fw_unit(dev), id);
 181
 182        for (; id_table->match_flags != 0; id_table++)
 183                if (match_ids(id_table, id))
 184                        return 1;
 185
 186        return 0;
 187}
 188
 189static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
 190{
 191        int id[] = {0, 0, 0, 0};
 192
 193        get_modalias_ids(unit, id);
 194
 195        return snprintf(buffer, buffer_size,
 196                        "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
 197                        id[0], id[1], id[2], id[3]);
 198}
 199
 200static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 201{
 202        struct fw_unit *unit = fw_unit(dev);
 203        char modalias[64];
 204
 205        get_modalias(unit, modalias, sizeof(modalias));
 206
 207        if (add_uevent_var(env, "MODALIAS=%s", modalias))
 208                return -ENOMEM;
 209
 210        return 0;
 211}
 212
 213struct bus_type fw_bus_type = {
 214        .name = "firewire",
 215        .match = fw_unit_match,
 216};
 217EXPORT_SYMBOL(fw_bus_type);
 218
 219int fw_device_enable_phys_dma(struct fw_device *device)
 220{
 221        int generation = device->generation;
 222
 223        /* device->node_id, accessed below, must not be older than generation */
 224        smp_rmb();
 225
 226        return device->card->driver->enable_phys_dma(device->card,
 227                                                     device->node_id,
 228                                                     generation);
 229}
 230EXPORT_SYMBOL(fw_device_enable_phys_dma);
 231
 232struct config_rom_attribute {
 233        struct device_attribute attr;
 234        u32 key;
 235};
 236
 237static ssize_t show_immediate(struct device *dev,
 238                              struct device_attribute *dattr, char *buf)
 239{
 240        struct config_rom_attribute *attr =
 241                container_of(dattr, struct config_rom_attribute, attr);
 242        struct fw_csr_iterator ci;
 243        const u32 *dir;
 244        int key, value, ret = -ENOENT;
 245
 246        down_read(&fw_device_rwsem);
 247
 248        if (is_fw_unit(dev))
 249                dir = fw_unit(dev)->directory;
 250        else
 251                dir = fw_device(dev)->config_rom + 5;
 252
 253        fw_csr_iterator_init(&ci, dir);
 254        while (fw_csr_iterator_next(&ci, &key, &value))
 255                if (attr->key == key) {
 256                        ret = snprintf(buf, buf ? PAGE_SIZE : 0,
 257                                       "0x%06x\n", value);
 258                        break;
 259                }
 260
 261        up_read(&fw_device_rwsem);
 262
 263        return ret;
 264}
 265
 266#define IMMEDIATE_ATTR(name, key)                               \
 267        { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
 268
 269static ssize_t show_text_leaf(struct device *dev,
 270                              struct device_attribute *dattr, char *buf)
 271{
 272        struct config_rom_attribute *attr =
 273                container_of(dattr, struct config_rom_attribute, attr);
 274        const u32 *dir;
 275        size_t bufsize;
 276        char dummy_buf[2];
 277        int ret;
 278
 279        down_read(&fw_device_rwsem);
 280
 281        if (is_fw_unit(dev))
 282                dir = fw_unit(dev)->directory;
 283        else
 284                dir = fw_device(dev)->config_rom + 5;
 285
 286        if (buf) {
 287                bufsize = PAGE_SIZE - 1;
 288        } else {
 289                buf = dummy_buf;
 290                bufsize = 1;
 291        }
 292
 293        ret = fw_csr_string(dir, attr->key, buf, bufsize);
 294
 295        if (ret >= 0) {
 296                /* Strip trailing whitespace and add newline. */
 297                while (ret > 0 && isspace(buf[ret - 1]))
 298                        ret--;
 299                strcpy(buf + ret, "\n");
 300                ret++;
 301        }
 302
 303        up_read(&fw_device_rwsem);
 304
 305        return ret;
 306}
 307
 308#define TEXT_LEAF_ATTR(name, key)                               \
 309        { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
 310
 311static struct config_rom_attribute config_rom_attributes[] = {
 312        IMMEDIATE_ATTR(vendor, CSR_VENDOR),
 313        IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
 314        IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
 315        IMMEDIATE_ATTR(version, CSR_VERSION),
 316        IMMEDIATE_ATTR(model, CSR_MODEL),
 317        TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
 318        TEXT_LEAF_ATTR(model_name, CSR_MODEL),
 319        TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
 320};
 321
 322static void init_fw_attribute_group(struct device *dev,
 323                                    struct device_attribute *attrs,
 324                                    struct fw_attribute_group *group)
 325{
 326        struct device_attribute *attr;
 327        int i, j;
 328
 329        for (j = 0; attrs[j].attr.name != NULL; j++)
 330                group->attrs[j] = &attrs[j].attr;
 331
 332        for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
 333                attr = &config_rom_attributes[i].attr;
 334                if (attr->show(dev, attr, NULL) < 0)
 335                        continue;
 336                group->attrs[j++] = &attr->attr;
 337        }
 338
 339        group->attrs[j] = NULL;
 340        group->groups[0] = &group->group;
 341        group->groups[1] = NULL;
 342        group->group.attrs = group->attrs;
 343        dev->groups = (const struct attribute_group **) group->groups;
 344}
 345
 346static ssize_t modalias_show(struct device *dev,
 347                             struct device_attribute *attr, char *buf)
 348{
 349        struct fw_unit *unit = fw_unit(dev);
 350        int length;
 351
 352        length = get_modalias(unit, buf, PAGE_SIZE);
 353        strcpy(buf + length, "\n");
 354
 355        return length + 1;
 356}
 357
 358static ssize_t rom_index_show(struct device *dev,
 359                              struct device_attribute *attr, char *buf)
 360{
 361        struct fw_device *device = fw_device(dev->parent);
 362        struct fw_unit *unit = fw_unit(dev);
 363
 364        return snprintf(buf, PAGE_SIZE, "%d\n",
 365                        (int)(unit->directory - device->config_rom));
 366}
 367
 368static struct device_attribute fw_unit_attributes[] = {
 369        __ATTR_RO(modalias),
 370        __ATTR_RO(rom_index),
 371        __ATTR_NULL,
 372};
 373
 374static ssize_t config_rom_show(struct device *dev,
 375                               struct device_attribute *attr, char *buf)
 376{
 377        struct fw_device *device = fw_device(dev);
 378        size_t length;
 379
 380        down_read(&fw_device_rwsem);
 381        length = device->config_rom_length * 4;
 382        memcpy(buf, device->config_rom, length);
 383        up_read(&fw_device_rwsem);
 384
 385        return length;
 386}
 387
 388static ssize_t guid_show(struct device *dev,
 389                         struct device_attribute *attr, char *buf)
 390{
 391        struct fw_device *device = fw_device(dev);
 392        int ret;
 393
 394        down_read(&fw_device_rwsem);
 395        ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
 396                       device->config_rom[3], device->config_rom[4]);
 397        up_read(&fw_device_rwsem);
 398
 399        return ret;
 400}
 401
 402static ssize_t is_local_show(struct device *dev,
 403                             struct device_attribute *attr, char *buf)
 404{
 405        struct fw_device *device = fw_device(dev);
 406
 407        return sprintf(buf, "%u\n", device->is_local);
 408}
 409
 410static int units_sprintf(char *buf, const u32 *directory)
 411{
 412        struct fw_csr_iterator ci;
 413        int key, value;
 414        int specifier_id = 0;
 415        int version = 0;
 416
 417        fw_csr_iterator_init(&ci, directory);
 418        while (fw_csr_iterator_next(&ci, &key, &value)) {
 419                switch (key) {
 420                case CSR_SPECIFIER_ID:
 421                        specifier_id = value;
 422                        break;
 423                case CSR_VERSION:
 424                        version = value;
 425                        break;
 426                }
 427        }
 428
 429        return sprintf(buf, "0x%06x:0x%06x ", specifier_id, version);
 430}
 431
 432static ssize_t units_show(struct device *dev,
 433                          struct device_attribute *attr, char *buf)
 434{
 435        struct fw_device *device = fw_device(dev);
 436        struct fw_csr_iterator ci;
 437        int key, value, i = 0;
 438
 439        down_read(&fw_device_rwsem);
 440        fw_csr_iterator_init(&ci, &device->config_rom[5]);
 441        while (fw_csr_iterator_next(&ci, &key, &value)) {
 442                if (key != (CSR_UNIT | CSR_DIRECTORY))
 443                        continue;
 444                i += units_sprintf(&buf[i], ci.p + value - 1);
 445                if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
 446                        break;
 447        }
 448        up_read(&fw_device_rwsem);
 449
 450        if (i)
 451                buf[i - 1] = '\n';
 452
 453        return i;
 454}
 455
 456static struct device_attribute fw_device_attributes[] = {
 457        __ATTR_RO(config_rom),
 458        __ATTR_RO(guid),
 459        __ATTR_RO(is_local),
 460        __ATTR_RO(units),
 461        __ATTR_NULL,
 462};
 463
 464static int read_rom(struct fw_device *device,
 465                    int generation, int index, u32 *data)
 466{
 467        u64 offset = (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4;
 468        int i, rcode;
 469
 470        /* device->node_id, accessed below, must not be older than generation */
 471        smp_rmb();
 472
 473        for (i = 10; i < 100; i += 10) {
 474                rcode = fw_run_transaction(device->card,
 475                                TCODE_READ_QUADLET_REQUEST, device->node_id,
 476                                generation, device->max_speed, offset, data, 4);
 477                if (rcode != RCODE_BUSY)
 478                        break;
 479                msleep(i);
 480        }
 481        be32_to_cpus(data);
 482
 483        return rcode;
 484}
 485
 486#define MAX_CONFIG_ROM_SIZE 256
 487
 488/*
 489 * Read the bus info block, perform a speed probe, and read all of the rest of
 490 * the config ROM.  We do all this with a cached bus generation.  If the bus
 491 * generation changes under us, read_config_rom will fail and get retried.
 492 * It's better to start all over in this case because the node from which we
 493 * are reading the ROM may have changed the ROM during the reset.
 494 * Returns either a result code or a negative error code.
 495 */
 496static int read_config_rom(struct fw_device *device, int generation)
 497{
 498        struct fw_card *card = device->card;
 499        const u32 *old_rom, *new_rom;
 500        u32 *rom, *stack;
 501        u32 sp, key;
 502        int i, end, length, ret;
 503
 504        rom = kmalloc(sizeof(*rom) * MAX_CONFIG_ROM_SIZE +
 505                      sizeof(*stack) * MAX_CONFIG_ROM_SIZE, GFP_KERNEL);
 506        if (rom == NULL)
 507                return -ENOMEM;
 508
 509        stack = &rom[MAX_CONFIG_ROM_SIZE];
 510        memset(rom, 0, sizeof(*rom) * MAX_CONFIG_ROM_SIZE);
 511
 512        device->max_speed = SCODE_100;
 513
 514        /* First read the bus info block. */
 515        for (i = 0; i < 5; i++) {
 516                ret = read_rom(device, generation, i, &rom[i]);
 517                if (ret != RCODE_COMPLETE)
 518                        goto out;
 519                /*
 520                 * As per IEEE1212 7.2, during initialization, devices can
 521                 * reply with a 0 for the first quadlet of the config
 522                 * rom to indicate that they are booting (for example,
 523                 * if the firmware is on the disk of a external
 524                 * harddisk).  In that case we just fail, and the
 525                 * retry mechanism will try again later.
 526                 */
 527                if (i == 0 && rom[i] == 0) {
 528                        ret = RCODE_BUSY;
 529                        goto out;
 530                }
 531        }
 532
 533        device->max_speed = device->node->max_speed;
 534
 535        /*
 536         * Determine the speed of
 537         *   - devices with link speed less than PHY speed,
 538         *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
 539         *   - all devices if there are 1394b repeaters.
 540         * Note, we cannot use the bus info block's link_spd as starting point
 541         * because some buggy firmwares set it lower than necessary and because
 542         * 1394-1995 nodes do not have the field.
 543         */
 544        if ((rom[2] & 0x7) < device->max_speed ||
 545            device->max_speed == SCODE_BETA ||
 546            card->beta_repeaters_present) {
 547                u32 dummy;
 548
 549                /* for S1600 and S3200 */
 550                if (device->max_speed == SCODE_BETA)
 551                        device->max_speed = card->link_speed;
 552
 553                while (device->max_speed > SCODE_100) {
 554                        if (read_rom(device, generation, 0, &dummy) ==
 555                            RCODE_COMPLETE)
 556                                break;
 557                        device->max_speed--;
 558                }
 559        }
 560
 561        /*
 562         * Now parse the config rom.  The config rom is a recursive
 563         * directory structure so we parse it using a stack of
 564         * references to the blocks that make up the structure.  We
 565         * push a reference to the root directory on the stack to
 566         * start things off.
 567         */
 568        length = i;
 569        sp = 0;
 570        stack[sp++] = 0xc0000005;
 571        while (sp > 0) {
 572                /*
 573                 * Pop the next block reference of the stack.  The
 574                 * lower 24 bits is the offset into the config rom,
 575                 * the upper 8 bits are the type of the reference the
 576                 * block.
 577                 */
 578                key = stack[--sp];
 579                i = key & 0xffffff;
 580                if (WARN_ON(i >= MAX_CONFIG_ROM_SIZE)) {
 581                        ret = -ENXIO;
 582                        goto out;
 583                }
 584
 585                /* Read header quadlet for the block to get the length. */
 586                ret = read_rom(device, generation, i, &rom[i]);
 587                if (ret != RCODE_COMPLETE)
 588                        goto out;
 589                end = i + (rom[i] >> 16) + 1;
 590                if (end > MAX_CONFIG_ROM_SIZE) {
 591                        /*
 592                         * This block extends outside the config ROM which is
 593                         * a firmware bug.  Ignore this whole block, i.e.
 594                         * simply set a fake block length of 0.
 595                         */
 596                        fw_err(card, "skipped invalid ROM block %x at %llx\n",
 597                               rom[i],
 598                               i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
 599                        rom[i] = 0;
 600                        end = i;
 601                }
 602                i++;
 603
 604                /*
 605                 * Now read in the block.  If this is a directory
 606                 * block, check the entries as we read them to see if
 607                 * it references another block, and push it in that case.
 608                 */
 609                for (; i < end; i++) {
 610                        ret = read_rom(device, generation, i, &rom[i]);
 611                        if (ret != RCODE_COMPLETE)
 612                                goto out;
 613
 614                        if ((key >> 30) != 3 || (rom[i] >> 30) < 2)
 615                                continue;
 616                        /*
 617                         * Offset points outside the ROM.  May be a firmware
 618                         * bug or an Extended ROM entry (IEEE 1212-2001 clause
 619                         * 7.7.18).  Simply overwrite this pointer here by a
 620                         * fake immediate entry so that later iterators over
 621                         * the ROM don't have to check offsets all the time.
 622                         */
 623                        if (i + (rom[i] & 0xffffff) >= MAX_CONFIG_ROM_SIZE) {
 624                                fw_err(card,
 625                                       "skipped unsupported ROM entry %x at %llx\n",
 626                                       rom[i],
 627                                       i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
 628                                rom[i] = 0;
 629                                continue;
 630                        }
 631                        stack[sp++] = i + rom[i];
 632                }
 633                if (length < i)
 634                        length = i;
 635        }
 636
 637        old_rom = device->config_rom;
 638        new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
 639        if (new_rom == NULL) {
 640                ret = -ENOMEM;
 641                goto out;
 642        }
 643
 644        down_write(&fw_device_rwsem);
 645        device->config_rom = new_rom;
 646        device->config_rom_length = length;
 647        up_write(&fw_device_rwsem);
 648
 649        kfree(old_rom);
 650        ret = RCODE_COMPLETE;
 651        device->max_rec = rom[2] >> 12 & 0xf;
 652        device->cmc     = rom[2] >> 30 & 1;
 653        device->irmc    = rom[2] >> 31 & 1;
 654 out:
 655        kfree(rom);
 656
 657        return ret;
 658}
 659
 660static void fw_unit_release(struct device *dev)
 661{
 662        struct fw_unit *unit = fw_unit(dev);
 663
 664        fw_device_put(fw_parent_device(unit));
 665        kfree(unit);
 666}
 667
 668static struct device_type fw_unit_type = {
 669        .uevent         = fw_unit_uevent,
 670        .release        = fw_unit_release,
 671};
 672
 673static bool is_fw_unit(struct device *dev)
 674{
 675        return dev->type == &fw_unit_type;
 676}
 677
 678static void create_units(struct fw_device *device)
 679{
 680        struct fw_csr_iterator ci;
 681        struct fw_unit *unit;
 682        int key, value, i;
 683
 684        i = 0;
 685        fw_csr_iterator_init(&ci, &device->config_rom[5]);
 686        while (fw_csr_iterator_next(&ci, &key, &value)) {
 687                if (key != (CSR_UNIT | CSR_DIRECTORY))
 688                        continue;
 689
 690                /*
 691                 * Get the address of the unit directory and try to
 692                 * match the drivers id_tables against it.
 693                 */
 694                unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 695                if (unit == NULL)
 696                        continue;
 697
 698                unit->directory = ci.p + value - 1;
 699                unit->device.bus = &fw_bus_type;
 700                unit->device.type = &fw_unit_type;
 701                unit->device.parent = &device->device;
 702                dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
 703
 704                BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
 705                                ARRAY_SIZE(fw_unit_attributes) +
 706                                ARRAY_SIZE(config_rom_attributes));
 707                init_fw_attribute_group(&unit->device,
 708                                        fw_unit_attributes,
 709                                        &unit->attribute_group);
 710
 711                if (device_register(&unit->device) < 0)
 712                        goto skip_unit;
 713
 714                fw_device_get(device);
 715                continue;
 716
 717        skip_unit:
 718                kfree(unit);
 719        }
 720}
 721
 722static int shutdown_unit(struct device *device, void *data)
 723{
 724        device_unregister(device);
 725
 726        return 0;
 727}
 728
 729/*
 730 * fw_device_rwsem acts as dual purpose mutex:
 731 *   - serializes accesses to fw_device_idr,
 732 *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 733 *     fw_unit.directory, unless those accesses happen at safe occasions
 734 */
 735DECLARE_RWSEM(fw_device_rwsem);
 736
 737DEFINE_IDR(fw_device_idr);
 738int fw_cdev_major;
 739
 740struct fw_device *fw_device_get_by_devt(dev_t devt)
 741{
 742        struct fw_device *device;
 743
 744        down_read(&fw_device_rwsem);
 745        device = idr_find(&fw_device_idr, MINOR(devt));
 746        if (device)
 747                fw_device_get(device);
 748        up_read(&fw_device_rwsem);
 749
 750        return device;
 751}
 752
 753struct workqueue_struct *fw_workqueue;
 754EXPORT_SYMBOL(fw_workqueue);
 755
 756static void fw_schedule_device_work(struct fw_device *device,
 757                                    unsigned long delay)
 758{
 759        queue_delayed_work(fw_workqueue, &device->work, delay);
 760}
 761
 762/*
 763 * These defines control the retry behavior for reading the config
 764 * rom.  It shouldn't be necessary to tweak these; if the device
 765 * doesn't respond to a config rom read within 10 seconds, it's not
 766 * going to respond at all.  As for the initial delay, a lot of
 767 * devices will be able to respond within half a second after bus
 768 * reset.  On the other hand, it's not really worth being more
 769 * aggressive than that, since it scales pretty well; if 10 devices
 770 * are plugged in, they're all getting read within one second.
 771 */
 772
 773#define MAX_RETRIES     10
 774#define RETRY_DELAY     (3 * HZ)
 775#define INITIAL_DELAY   (HZ / 2)
 776#define SHUTDOWN_DELAY  (2 * HZ)
 777
 778static void fw_device_shutdown(struct work_struct *work)
 779{
 780        struct fw_device *device =
 781                container_of(work, struct fw_device, work.work);
 782        int minor = MINOR(device->device.devt);
 783
 784        if (time_before64(get_jiffies_64(),
 785                          device->card->reset_jiffies + SHUTDOWN_DELAY)
 786            && !list_empty(&device->card->link)) {
 787                fw_schedule_device_work(device, SHUTDOWN_DELAY);
 788                return;
 789        }
 790
 791        if (atomic_cmpxchg(&device->state,
 792                           FW_DEVICE_GONE,
 793                           FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
 794                return;
 795
 796        fw_device_cdev_remove(device);
 797        device_for_each_child(&device->device, NULL, shutdown_unit);
 798        device_unregister(&device->device);
 799
 800        down_write(&fw_device_rwsem);
 801        idr_remove(&fw_device_idr, minor);
 802        up_write(&fw_device_rwsem);
 803
 804        fw_device_put(device);
 805}
 806
 807static void fw_device_release(struct device *dev)
 808{
 809        struct fw_device *device = fw_device(dev);
 810        struct fw_card *card = device->card;
 811        unsigned long flags;
 812
 813        /*
 814         * Take the card lock so we don't set this to NULL while a
 815         * FW_NODE_UPDATED callback is being handled or while the
 816         * bus manager work looks at this node.
 817         */
 818        spin_lock_irqsave(&card->lock, flags);
 819        device->node->data = NULL;
 820        spin_unlock_irqrestore(&card->lock, flags);
 821
 822        fw_node_put(device->node);
 823        kfree(device->config_rom);
 824        kfree(device);
 825        fw_card_put(card);
 826}
 827
 828static struct device_type fw_device_type = {
 829        .release = fw_device_release,
 830};
 831
 832static bool is_fw_device(struct device *dev)
 833{
 834        return dev->type == &fw_device_type;
 835}
 836
 837static int update_unit(struct device *dev, void *data)
 838{
 839        struct fw_unit *unit = fw_unit(dev);
 840        struct fw_driver *driver = (struct fw_driver *)dev->driver;
 841
 842        if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
 843                device_lock(dev);
 844                driver->update(unit);
 845                device_unlock(dev);
 846        }
 847
 848        return 0;
 849}
 850
 851static void fw_device_update(struct work_struct *work)
 852{
 853        struct fw_device *device =
 854                container_of(work, struct fw_device, work.work);
 855
 856        fw_device_cdev_update(device);
 857        device_for_each_child(&device->device, NULL, update_unit);
 858}
 859
 860/*
 861 * If a device was pending for deletion because its node went away but its
 862 * bus info block and root directory header matches that of a newly discovered
 863 * device, revive the existing fw_device.
 864 * The newly allocated fw_device becomes obsolete instead.
 865 */
 866static int lookup_existing_device(struct device *dev, void *data)
 867{
 868        struct fw_device *old = fw_device(dev);
 869        struct fw_device *new = data;
 870        struct fw_card *card = new->card;
 871        int match = 0;
 872
 873        if (!is_fw_device(dev))
 874                return 0;
 875
 876        down_read(&fw_device_rwsem); /* serialize config_rom access */
 877        spin_lock_irq(&card->lock);  /* serialize node access */
 878
 879        if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
 880            atomic_cmpxchg(&old->state,
 881                           FW_DEVICE_GONE,
 882                           FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 883                struct fw_node *current_node = new->node;
 884                struct fw_node *obsolete_node = old->node;
 885
 886                new->node = obsolete_node;
 887                new->node->data = new;
 888                old->node = current_node;
 889                old->node->data = old;
 890
 891                old->max_speed = new->max_speed;
 892                old->node_id = current_node->node_id;
 893                smp_wmb();  /* update node_id before generation */
 894                old->generation = card->generation;
 895                old->config_rom_retries = 0;
 896                fw_notice(card, "rediscovered device %s\n", dev_name(dev));
 897
 898                PREPARE_DELAYED_WORK(&old->work, fw_device_update);
 899                fw_schedule_device_work(old, 0);
 900
 901                if (current_node == card->root_node)
 902                        fw_schedule_bm_work(card, 0);
 903
 904                match = 1;
 905        }
 906
 907        spin_unlock_irq(&card->lock);
 908        up_read(&fw_device_rwsem);
 909
 910        return match;
 911}
 912
 913enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
 914
 915static void set_broadcast_channel(struct fw_device *device, int generation)
 916{
 917        struct fw_card *card = device->card;
 918        __be32 data;
 919        int rcode;
 920
 921        if (!card->broadcast_channel_allocated)
 922                return;
 923
 924        /*
 925         * The Broadcast_Channel Valid bit is required by nodes which want to
 926         * transmit on this channel.  Such transmissions are practically
 927         * exclusive to IP over 1394 (RFC 2734).  IP capable nodes are required
 928         * to be IRM capable and have a max_rec of 8 or more.  We use this fact
 929         * to narrow down to which nodes we send Broadcast_Channel updates.
 930         */
 931        if (!device->irmc || device->max_rec < 8)
 932                return;
 933
 934        /*
 935         * Some 1394-1995 nodes crash if this 1394a-2000 register is written.
 936         * Perform a read test first.
 937         */
 938        if (device->bc_implemented == BC_UNKNOWN) {
 939                rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
 940                                device->node_id, generation, device->max_speed,
 941                                CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 942                                &data, 4);
 943                switch (rcode) {
 944                case RCODE_COMPLETE:
 945                        if (data & cpu_to_be32(1 << 31)) {
 946                                device->bc_implemented = BC_IMPLEMENTED;
 947                                break;
 948                        }
 949                        /* else fall through to case address error */
 950                case RCODE_ADDRESS_ERROR:
 951                        device->bc_implemented = BC_UNIMPLEMENTED;
 952                }
 953        }
 954
 955        if (device->bc_implemented == BC_IMPLEMENTED) {
 956                data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
 957                                   BROADCAST_CHANNEL_VALID);
 958                fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
 959                                device->node_id, generation, device->max_speed,
 960                                CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 961                                &data, 4);
 962        }
 963}
 964
 965int fw_device_set_broadcast_channel(struct device *dev, void *gen)
 966{
 967        if (is_fw_device(dev))
 968                set_broadcast_channel(fw_device(dev), (long)gen);
 969
 970        return 0;
 971}
 972
 973static void fw_device_init(struct work_struct *work)
 974{
 975        struct fw_device *device =
 976                container_of(work, struct fw_device, work.work);
 977        struct fw_card *card = device->card;
 978        struct device *revived_dev;
 979        int minor, ret;
 980
 981        /*
 982         * All failure paths here set node->data to NULL, so that we
 983         * don't try to do device_for_each_child() on a kfree()'d
 984         * device.
 985         */
 986
 987        ret = read_config_rom(device, device->generation);
 988        if (ret != RCODE_COMPLETE) {
 989                if (device->config_rom_retries < MAX_RETRIES &&
 990                    atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 991                        device->config_rom_retries++;
 992                        fw_schedule_device_work(device, RETRY_DELAY);
 993                } else {
 994                        if (device->node->link_on)
 995                                fw_notice(card, "giving up on node %x: reading config rom failed: %s\n",
 996                                          device->node_id,
 997                                          fw_rcode_string(ret));
 998                        if (device->node == card->root_node)
 999                                fw_schedule_bm_work(card, 0);
1000                        fw_device_release(&device->device);
1001                }
1002                return;
1003        }
1004
1005        revived_dev = device_find_child(card->device,
1006                                        device, lookup_existing_device);
1007        if (revived_dev) {
1008                put_device(revived_dev);
1009                fw_device_release(&device->device);
1010
1011                return;
1012        }
1013
1014        device_initialize(&device->device);
1015
1016        fw_device_get(device);
1017        down_write(&fw_device_rwsem);
1018        minor = idr_alloc(&fw_device_idr, device, 0, 1 << MINORBITS,
1019                        GFP_KERNEL);
1020        up_write(&fw_device_rwsem);
1021
1022        if (minor < 0)
1023                goto error;
1024
1025        device->device.bus = &fw_bus_type;
1026        device->device.type = &fw_device_type;
1027        device->device.parent = card->device;
1028        device->device.devt = MKDEV(fw_cdev_major, minor);
1029        dev_set_name(&device->device, "fw%d", minor);
1030
1031        BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
1032                        ARRAY_SIZE(fw_device_attributes) +
1033                        ARRAY_SIZE(config_rom_attributes));
1034        init_fw_attribute_group(&device->device,
1035                                fw_device_attributes,
1036                                &device->attribute_group);
1037
1038        if (device_add(&device->device)) {
1039                fw_err(card, "failed to add device\n");
1040                goto error_with_cdev;
1041        }
1042
1043        create_units(device);
1044
1045        /*
1046         * Transition the device to running state.  If it got pulled
1047         * out from under us while we did the intialization work, we
1048         * have to shut down the device again here.  Normally, though,
1049         * fw_node_event will be responsible for shutting it down when
1050         * necessary.  We have to use the atomic cmpxchg here to avoid
1051         * racing with the FW_NODE_DESTROYED case in
1052         * fw_node_event().
1053         */
1054        if (atomic_cmpxchg(&device->state,
1055                           FW_DEVICE_INITIALIZING,
1056                           FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
1057                PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1058                fw_schedule_device_work(device, SHUTDOWN_DELAY);
1059        } else {
1060                fw_notice(card, "created device %s: GUID %08x%08x, S%d00\n",
1061                          dev_name(&device->device),
1062                          device->config_rom[3], device->config_rom[4],
1063                          1 << device->max_speed);
1064                device->config_rom_retries = 0;
1065
1066                set_broadcast_channel(device, device->generation);
1067
1068                add_device_randomness(&device->config_rom[3], 8);
1069        }
1070
1071        /*
1072         * Reschedule the IRM work if we just finished reading the
1073         * root node config rom.  If this races with a bus reset we
1074         * just end up running the IRM work a couple of extra times -
1075         * pretty harmless.
1076         */
1077        if (device->node == card->root_node)
1078                fw_schedule_bm_work(card, 0);
1079
1080        return;
1081
1082 error_with_cdev:
1083        down_write(&fw_device_rwsem);
1084        idr_remove(&fw_device_idr, minor);
1085        up_write(&fw_device_rwsem);
1086 error:
1087        fw_device_put(device);          /* fw_device_idr's reference */
1088
1089        put_device(&device->device);    /* our reference */
1090}
1091
1092/* Reread and compare bus info block and header of root directory */
1093static int reread_config_rom(struct fw_device *device, int generation,
1094                             bool *changed)
1095{
1096        u32 q;
1097        int i, rcode;
1098
1099        for (i = 0; i < 6; i++) {
1100                rcode = read_rom(device, generation, i, &q);
1101                if (rcode != RCODE_COMPLETE)
1102                        return rcode;
1103
1104                if (i == 0 && q == 0)
1105                        /* inaccessible (see read_config_rom); retry later */
1106                        return RCODE_BUSY;
1107
1108                if (q != device->config_rom[i]) {
1109                        *changed = true;
1110                        return RCODE_COMPLETE;
1111                }
1112        }
1113
1114        *changed = false;
1115        return RCODE_COMPLETE;
1116}
1117
1118static void fw_device_refresh(struct work_struct *work)
1119{
1120        struct fw_device *device =
1121                container_of(work, struct fw_device, work.work);
1122        struct fw_card *card = device->card;
1123        int ret, node_id = device->node_id;
1124        bool changed;
1125
1126        ret = reread_config_rom(device, device->generation, &changed);
1127        if (ret != RCODE_COMPLETE)
1128                goto failed_config_rom;
1129
1130        if (!changed) {
1131                if (atomic_cmpxchg(&device->state,
1132                                   FW_DEVICE_INITIALIZING,
1133                                   FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1134                        goto gone;
1135
1136                fw_device_update(work);
1137                device->config_rom_retries = 0;
1138                goto out;
1139        }
1140
1141        /*
1142         * Something changed.  We keep things simple and don't investigate
1143         * further.  We just destroy all previous units and create new ones.
1144         */
1145        device_for_each_child(&device->device, NULL, shutdown_unit);
1146
1147        ret = read_config_rom(device, device->generation);
1148        if (ret != RCODE_COMPLETE)
1149                goto failed_config_rom;
1150
1151        fw_device_cdev_update(device);
1152        create_units(device);
1153
1154        /* Userspace may want to re-read attributes. */
1155        kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1156
1157        if (atomic_cmpxchg(&device->state,
1158                           FW_DEVICE_INITIALIZING,
1159                           FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1160                goto gone;
1161
1162        fw_notice(card, "refreshed device %s\n", dev_name(&device->device));
1163        device->config_rom_retries = 0;
1164        goto out;
1165
1166 failed_config_rom:
1167        if (device->config_rom_retries < MAX_RETRIES &&
1168            atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1169                device->config_rom_retries++;
1170                fw_schedule_device_work(device, RETRY_DELAY);
1171                return;
1172        }
1173
1174        fw_notice(card, "giving up on refresh of device %s: %s\n",
1175                  dev_name(&device->device), fw_rcode_string(ret));
1176 gone:
1177        atomic_set(&device->state, FW_DEVICE_GONE);
1178        PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1179        fw_schedule_device_work(device, SHUTDOWN_DELAY);
1180 out:
1181        if (node_id == card->root_node->node_id)
1182                fw_schedule_bm_work(card, 0);
1183}
1184
1185void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1186{
1187        struct fw_device *device;
1188
1189        switch (event) {
1190        case FW_NODE_CREATED:
1191                /*
1192                 * Attempt to scan the node, regardless whether its self ID has
1193                 * the L (link active) flag set or not.  Some broken devices
1194                 * send L=0 but have an up-and-running link; others send L=1
1195                 * without actually having a link.
1196                 */
1197 create:
1198                device = kzalloc(sizeof(*device), GFP_ATOMIC);
1199                if (device == NULL)
1200                        break;
1201
1202                /*
1203                 * Do minimal intialization of the device here, the
1204                 * rest will happen in fw_device_init().
1205                 *
1206                 * Attention:  A lot of things, even fw_device_get(),
1207                 * cannot be done before fw_device_init() finished!
1208                 * You can basically just check device->state and
1209                 * schedule work until then, but only while holding
1210                 * card->lock.
1211                 */
1212                atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1213                device->card = fw_card_get(card);
1214                device->node = fw_node_get(node);
1215                device->node_id = node->node_id;
1216                device->generation = card->generation;
1217                device->is_local = node == card->local_node;
1218                mutex_init(&device->client_list_mutex);
1219                INIT_LIST_HEAD(&device->client_list);
1220
1221                /*
1222                 * Set the node data to point back to this device so
1223                 * FW_NODE_UPDATED callbacks can update the node_id
1224                 * and generation for the device.
1225                 */
1226                node->data = device;
1227
1228                /*
1229                 * Many devices are slow to respond after bus resets,
1230                 * especially if they are bus powered and go through
1231                 * power-up after getting plugged in.  We schedule the
1232                 * first config rom scan half a second after bus reset.
1233                 */
1234                INIT_DELAYED_WORK(&device->work, fw_device_init);
1235                fw_schedule_device_work(device, INITIAL_DELAY);
1236                break;
1237
1238        case FW_NODE_INITIATED_RESET:
1239        case FW_NODE_LINK_ON:
1240                device = node->data;
1241                if (device == NULL)
1242                        goto create;
1243
1244                device->node_id = node->node_id;
1245                smp_wmb();  /* update node_id before generation */
1246                device->generation = card->generation;
1247                if (atomic_cmpxchg(&device->state,
1248                            FW_DEVICE_RUNNING,
1249                            FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1250                        PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
1251                        fw_schedule_device_work(device,
1252                                device->is_local ? 0 : INITIAL_DELAY);
1253                }
1254                break;
1255
1256        case FW_NODE_UPDATED:
1257                device = node->data;
1258                if (device == NULL)
1259                        break;
1260
1261                device->node_id = node->node_id;
1262                smp_wmb();  /* update node_id before generation */
1263                device->generation = card->generation;
1264                if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1265                        PREPARE_DELAYED_WORK(&device->work, fw_device_update);
1266                        fw_schedule_device_work(device, 0);
1267                }
1268                break;
1269
1270        case FW_NODE_DESTROYED:
1271        case FW_NODE_LINK_OFF:
1272                if (!node->data)
1273                        break;
1274
1275                /*
1276                 * Destroy the device associated with the node.  There
1277                 * are two cases here: either the device is fully
1278                 * initialized (FW_DEVICE_RUNNING) or we're in the
1279                 * process of reading its config rom
1280                 * (FW_DEVICE_INITIALIZING).  If it is fully
1281                 * initialized we can reuse device->work to schedule a
1282                 * full fw_device_shutdown().  If not, there's work
1283                 * scheduled to read it's config rom, and we just put
1284                 * the device in shutdown state to have that code fail
1285                 * to create the device.
1286                 */
1287                device = node->data;
1288                if (atomic_xchg(&device->state,
1289                                FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1290                        PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
1291                        fw_schedule_device_work(device,
1292                                list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1293                }
1294                break;
1295        }
1296}
1297
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