linux/drivers/firewire/core-device.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Device probing and sysfs code.
   4 *
   5 * Copyright (C) 2005-2006  Kristian Hoegsberg <krh@bitplanet.net>
   6 */
   7
   8#include <linux/bug.h>
   9#include <linux/ctype.h>
  10#include <linux/delay.h>
  11#include <linux/device.h>
  12#include <linux/errno.h>
  13#include <linux/firewire.h>
  14#include <linux/firewire-constants.h>
  15#include <linux/idr.h>
  16#include <linux/jiffies.h>
  17#include <linux/kobject.h>
  18#include <linux/list.h>
  19#include <linux/mod_devicetable.h>
  20#include <linux/module.h>
  21#include <linux/mutex.h>
  22#include <linux/random.h>
  23#include <linux/rwsem.h>
  24#include <linux/slab.h>
  25#include <linux/spinlock.h>
  26#include <linux/string.h>
  27#include <linux/workqueue.h>
  28
  29#include <linux/atomic.h>
  30#include <asm/byteorder.h>
  31
  32#include "core.h"
  33
  34void fw_csr_iterator_init(struct fw_csr_iterator *ci, const u32 *p)
  35{
  36        ci->p = p + 1;
  37        ci->end = ci->p + (p[0] >> 16);
  38}
  39EXPORT_SYMBOL(fw_csr_iterator_init);
  40
  41int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
  42{
  43        *key = *ci->p >> 24;
  44        *value = *ci->p & 0xffffff;
  45
  46        return ci->p++ < ci->end;
  47}
  48EXPORT_SYMBOL(fw_csr_iterator_next);
  49
  50static const u32 *search_leaf(const u32 *directory, int search_key)
  51{
  52        struct fw_csr_iterator ci;
  53        int last_key = 0, key, value;
  54
  55        fw_csr_iterator_init(&ci, directory);
  56        while (fw_csr_iterator_next(&ci, &key, &value)) {
  57                if (last_key == search_key &&
  58                    key == (CSR_DESCRIPTOR | CSR_LEAF))
  59                        return ci.p - 1 + value;
  60
  61                last_key = key;
  62        }
  63
  64        return NULL;
  65}
  66
  67static int textual_leaf_to_string(const u32 *block, char *buf, size_t size)
  68{
  69        unsigned int quadlets, i;
  70        char c;
  71
  72        if (!size || !buf)
  73                return -EINVAL;
  74
  75        quadlets = min(block[0] >> 16, 256U);
  76        if (quadlets < 2)
  77                return -ENODATA;
  78
  79        if (block[1] != 0 || block[2] != 0)
  80                /* unknown language/character set */
  81                return -ENODATA;
  82
  83        block += 3;
  84        quadlets -= 2;
  85        for (i = 0; i < quadlets * 4 && i < size - 1; i++) {
  86                c = block[i / 4] >> (24 - 8 * (i % 4));
  87                if (c == '\0')
  88                        break;
  89                buf[i] = c;
  90        }
  91        buf[i] = '\0';
  92
  93        return i;
  94}
  95
  96/**
  97 * fw_csr_string() - reads a string from the configuration ROM
  98 * @directory:  e.g. root directory or unit directory
  99 * @key:        the key of the preceding directory entry
 100 * @buf:        where to put the string
 101 * @size:       size of @buf, in bytes
 102 *
 103 * The string is taken from a minimal ASCII text descriptor leaf after
 104 * the immediate entry with @key.  The string is zero-terminated.
 105 * An overlong string is silently truncated such that it and the
 106 * zero byte fit into @size.
 107 *
 108 * Returns strlen(buf) or a negative error code.
 109 */
 110int fw_csr_string(const u32 *directory, int key, char *buf, size_t size)
 111{
 112        const u32 *leaf = search_leaf(directory, key);
 113        if (!leaf)
 114                return -ENOENT;
 115
 116        return textual_leaf_to_string(leaf, buf, size);
 117}
 118EXPORT_SYMBOL(fw_csr_string);
 119
 120static void get_ids(const u32 *directory, int *id)
 121{
 122        struct fw_csr_iterator ci;
 123        int key, value;
 124
 125        fw_csr_iterator_init(&ci, directory);
 126        while (fw_csr_iterator_next(&ci, &key, &value)) {
 127                switch (key) {
 128                case CSR_VENDOR:        id[0] = value; break;
 129                case CSR_MODEL:         id[1] = value; break;
 130                case CSR_SPECIFIER_ID:  id[2] = value; break;
 131                case CSR_VERSION:       id[3] = value; break;
 132                }
 133        }
 134}
 135
 136static void get_modalias_ids(struct fw_unit *unit, int *id)
 137{
 138        get_ids(&fw_parent_device(unit)->config_rom[5], id);
 139        get_ids(unit->directory, id);
 140}
 141
 142static bool match_ids(const struct ieee1394_device_id *id_table, int *id)
 143{
 144        int match = 0;
 145
 146        if (id[0] == id_table->vendor_id)
 147                match |= IEEE1394_MATCH_VENDOR_ID;
 148        if (id[1] == id_table->model_id)
 149                match |= IEEE1394_MATCH_MODEL_ID;
 150        if (id[2] == id_table->specifier_id)
 151                match |= IEEE1394_MATCH_SPECIFIER_ID;
 152        if (id[3] == id_table->version)
 153                match |= IEEE1394_MATCH_VERSION;
 154
 155        return (match & id_table->match_flags) == id_table->match_flags;
 156}
 157
 158static const struct ieee1394_device_id *unit_match(struct device *dev,
 159                                                   struct device_driver *drv)
 160{
 161        const struct ieee1394_device_id *id_table =
 162                        container_of(drv, struct fw_driver, driver)->id_table;
 163        int id[] = {0, 0, 0, 0};
 164
 165        get_modalias_ids(fw_unit(dev), id);
 166
 167        for (; id_table->match_flags != 0; id_table++)
 168                if (match_ids(id_table, id))
 169                        return id_table;
 170
 171        return NULL;
 172}
 173
 174static bool is_fw_unit(struct device *dev);
 175
 176static int fw_unit_match(struct device *dev, struct device_driver *drv)
 177{
 178        /* We only allow binding to fw_units. */
 179        return is_fw_unit(dev) && unit_match(dev, drv) != NULL;
 180}
 181
 182static int fw_unit_probe(struct device *dev)
 183{
 184        struct fw_driver *driver =
 185                        container_of(dev->driver, struct fw_driver, driver);
 186
 187        return driver->probe(fw_unit(dev), unit_match(dev, dev->driver));
 188}
 189
 190static int fw_unit_remove(struct device *dev)
 191{
 192        struct fw_driver *driver =
 193                        container_of(dev->driver, struct fw_driver, driver);
 194
 195        return driver->remove(fw_unit(dev)), 0;
 196}
 197
 198static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
 199{
 200        int id[] = {0, 0, 0, 0};
 201
 202        get_modalias_ids(unit, id);
 203
 204        return snprintf(buffer, buffer_size,
 205                        "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
 206                        id[0], id[1], id[2], id[3]);
 207}
 208
 209static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
 210{
 211        struct fw_unit *unit = fw_unit(dev);
 212        char modalias[64];
 213
 214        get_modalias(unit, modalias, sizeof(modalias));
 215
 216        if (add_uevent_var(env, "MODALIAS=%s", modalias))
 217                return -ENOMEM;
 218
 219        return 0;
 220}
 221
 222struct bus_type fw_bus_type = {
 223        .name = "firewire",
 224        .match = fw_unit_match,
 225        .probe = fw_unit_probe,
 226        .remove = fw_unit_remove,
 227};
 228EXPORT_SYMBOL(fw_bus_type);
 229
 230int fw_device_enable_phys_dma(struct fw_device *device)
 231{
 232        int generation = device->generation;
 233
 234        /* device->node_id, accessed below, must not be older than generation */
 235        smp_rmb();
 236
 237        return device->card->driver->enable_phys_dma(device->card,
 238                                                     device->node_id,
 239                                                     generation);
 240}
 241EXPORT_SYMBOL(fw_device_enable_phys_dma);
 242
 243struct config_rom_attribute {
 244        struct device_attribute attr;
 245        u32 key;
 246};
 247
 248static ssize_t show_immediate(struct device *dev,
 249                              struct device_attribute *dattr, char *buf)
 250{
 251        struct config_rom_attribute *attr =
 252                container_of(dattr, struct config_rom_attribute, attr);
 253        struct fw_csr_iterator ci;
 254        const u32 *dir;
 255        int key, value, ret = -ENOENT;
 256
 257        down_read(&fw_device_rwsem);
 258
 259        if (is_fw_unit(dev))
 260                dir = fw_unit(dev)->directory;
 261        else
 262                dir = fw_device(dev)->config_rom + 5;
 263
 264        fw_csr_iterator_init(&ci, dir);
 265        while (fw_csr_iterator_next(&ci, &key, &value))
 266                if (attr->key == key) {
 267                        ret = snprintf(buf, buf ? PAGE_SIZE : 0,
 268                                       "0x%06x\n", value);
 269                        break;
 270                }
 271
 272        up_read(&fw_device_rwsem);
 273
 274        return ret;
 275}
 276
 277#define IMMEDIATE_ATTR(name, key)                               \
 278        { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
 279
 280static ssize_t show_text_leaf(struct device *dev,
 281                              struct device_attribute *dattr, char *buf)
 282{
 283        struct config_rom_attribute *attr =
 284                container_of(dattr, struct config_rom_attribute, attr);
 285        const u32 *dir;
 286        size_t bufsize;
 287        char dummy_buf[2];
 288        int ret;
 289
 290        down_read(&fw_device_rwsem);
 291
 292        if (is_fw_unit(dev))
 293                dir = fw_unit(dev)->directory;
 294        else
 295                dir = fw_device(dev)->config_rom + 5;
 296
 297        if (buf) {
 298                bufsize = PAGE_SIZE - 1;
 299        } else {
 300                buf = dummy_buf;
 301                bufsize = 1;
 302        }
 303
 304        ret = fw_csr_string(dir, attr->key, buf, bufsize);
 305
 306        if (ret >= 0) {
 307                /* Strip trailing whitespace and add newline. */
 308                while (ret > 0 && isspace(buf[ret - 1]))
 309                        ret--;
 310                strcpy(buf + ret, "\n");
 311                ret++;
 312        }
 313
 314        up_read(&fw_device_rwsem);
 315
 316        return ret;
 317}
 318
 319#define TEXT_LEAF_ATTR(name, key)                               \
 320        { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
 321
 322static struct config_rom_attribute config_rom_attributes[] = {
 323        IMMEDIATE_ATTR(vendor, CSR_VENDOR),
 324        IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
 325        IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
 326        IMMEDIATE_ATTR(version, CSR_VERSION),
 327        IMMEDIATE_ATTR(model, CSR_MODEL),
 328        TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
 329        TEXT_LEAF_ATTR(model_name, CSR_MODEL),
 330        TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
 331};
 332
 333static void init_fw_attribute_group(struct device *dev,
 334                                    struct device_attribute *attrs,
 335                                    struct fw_attribute_group *group)
 336{
 337        struct device_attribute *attr;
 338        int i, j;
 339
 340        for (j = 0; attrs[j].attr.name != NULL; j++)
 341                group->attrs[j] = &attrs[j].attr;
 342
 343        for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
 344                attr = &config_rom_attributes[i].attr;
 345                if (attr->show(dev, attr, NULL) < 0)
 346                        continue;
 347                group->attrs[j++] = &attr->attr;
 348        }
 349
 350        group->attrs[j] = NULL;
 351        group->groups[0] = &group->group;
 352        group->groups[1] = NULL;
 353        group->group.attrs = group->attrs;
 354        dev->groups = (const struct attribute_group **) group->groups;
 355}
 356
 357static ssize_t modalias_show(struct device *dev,
 358                             struct device_attribute *attr, char *buf)
 359{
 360        struct fw_unit *unit = fw_unit(dev);
 361        int length;
 362
 363        length = get_modalias(unit, buf, PAGE_SIZE);
 364        strcpy(buf + length, "\n");
 365
 366        return length + 1;
 367}
 368
 369static ssize_t rom_index_show(struct device *dev,
 370                              struct device_attribute *attr, char *buf)
 371{
 372        struct fw_device *device = fw_device(dev->parent);
 373        struct fw_unit *unit = fw_unit(dev);
 374
 375        return snprintf(buf, PAGE_SIZE, "%d\n",
 376                        (int)(unit->directory - device->config_rom));
 377}
 378
 379static struct device_attribute fw_unit_attributes[] = {
 380        __ATTR_RO(modalias),
 381        __ATTR_RO(rom_index),
 382        __ATTR_NULL,
 383};
 384
 385static ssize_t config_rom_show(struct device *dev,
 386                               struct device_attribute *attr, char *buf)
 387{
 388        struct fw_device *device = fw_device(dev);
 389        size_t length;
 390
 391        down_read(&fw_device_rwsem);
 392        length = device->config_rom_length * 4;
 393        memcpy(buf, device->config_rom, length);
 394        up_read(&fw_device_rwsem);
 395
 396        return length;
 397}
 398
 399static ssize_t guid_show(struct device *dev,
 400                         struct device_attribute *attr, char *buf)
 401{
 402        struct fw_device *device = fw_device(dev);
 403        int ret;
 404
 405        down_read(&fw_device_rwsem);
 406        ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
 407                       device->config_rom[3], device->config_rom[4]);
 408        up_read(&fw_device_rwsem);
 409
 410        return ret;
 411}
 412
 413static ssize_t is_local_show(struct device *dev,
 414                             struct device_attribute *attr, char *buf)
 415{
 416        struct fw_device *device = fw_device(dev);
 417
 418        return sprintf(buf, "%u\n", device->is_local);
 419}
 420
 421static int units_sprintf(char *buf, const u32 *directory)
 422{
 423        struct fw_csr_iterator ci;
 424        int key, value;
 425        int specifier_id = 0;
 426        int version = 0;
 427
 428        fw_csr_iterator_init(&ci, directory);
 429        while (fw_csr_iterator_next(&ci, &key, &value)) {
 430                switch (key) {
 431                case CSR_SPECIFIER_ID:
 432                        specifier_id = value;
 433                        break;
 434                case CSR_VERSION:
 435                        version = value;
 436                        break;
 437                }
 438        }
 439
 440        return sprintf(buf, "0x%06x:0x%06x ", specifier_id, version);
 441}
 442
 443static ssize_t units_show(struct device *dev,
 444                          struct device_attribute *attr, char *buf)
 445{
 446        struct fw_device *device = fw_device(dev);
 447        struct fw_csr_iterator ci;
 448        int key, value, i = 0;
 449
 450        down_read(&fw_device_rwsem);
 451        fw_csr_iterator_init(&ci, &device->config_rom[5]);
 452        while (fw_csr_iterator_next(&ci, &key, &value)) {
 453                if (key != (CSR_UNIT | CSR_DIRECTORY))
 454                        continue;
 455                i += units_sprintf(&buf[i], ci.p + value - 1);
 456                if (i >= PAGE_SIZE - (8 + 1 + 8 + 1))
 457                        break;
 458        }
 459        up_read(&fw_device_rwsem);
 460
 461        if (i)
 462                buf[i - 1] = '\n';
 463
 464        return i;
 465}
 466
 467static struct device_attribute fw_device_attributes[] = {
 468        __ATTR_RO(config_rom),
 469        __ATTR_RO(guid),
 470        __ATTR_RO(is_local),
 471        __ATTR_RO(units),
 472        __ATTR_NULL,
 473};
 474
 475static int read_rom(struct fw_device *device,
 476                    int generation, int index, u32 *data)
 477{
 478        u64 offset = (CSR_REGISTER_BASE | CSR_CONFIG_ROM) + index * 4;
 479        int i, rcode;
 480
 481        /* device->node_id, accessed below, must not be older than generation */
 482        smp_rmb();
 483
 484        for (i = 10; i < 100; i += 10) {
 485                rcode = fw_run_transaction(device->card,
 486                                TCODE_READ_QUADLET_REQUEST, device->node_id,
 487                                generation, device->max_speed, offset, data, 4);
 488                if (rcode != RCODE_BUSY)
 489                        break;
 490                msleep(i);
 491        }
 492        be32_to_cpus(data);
 493
 494        return rcode;
 495}
 496
 497#define MAX_CONFIG_ROM_SIZE 256
 498
 499/*
 500 * Read the bus info block, perform a speed probe, and read all of the rest of
 501 * the config ROM.  We do all this with a cached bus generation.  If the bus
 502 * generation changes under us, read_config_rom will fail and get retried.
 503 * It's better to start all over in this case because the node from which we
 504 * are reading the ROM may have changed the ROM during the reset.
 505 * Returns either a result code or a negative error code.
 506 */
 507static int read_config_rom(struct fw_device *device, int generation)
 508{
 509        struct fw_card *card = device->card;
 510        const u32 *old_rom, *new_rom;
 511        u32 *rom, *stack;
 512        u32 sp, key;
 513        int i, end, length, ret;
 514
 515        rom = kmalloc(sizeof(*rom) * MAX_CONFIG_ROM_SIZE +
 516                      sizeof(*stack) * MAX_CONFIG_ROM_SIZE, GFP_KERNEL);
 517        if (rom == NULL)
 518                return -ENOMEM;
 519
 520        stack = &rom[MAX_CONFIG_ROM_SIZE];
 521        memset(rom, 0, sizeof(*rom) * MAX_CONFIG_ROM_SIZE);
 522
 523        device->max_speed = SCODE_100;
 524
 525        /* First read the bus info block. */
 526        for (i = 0; i < 5; i++) {
 527                ret = read_rom(device, generation, i, &rom[i]);
 528                if (ret != RCODE_COMPLETE)
 529                        goto out;
 530                /*
 531                 * As per IEEE1212 7.2, during initialization, devices can
 532                 * reply with a 0 for the first quadlet of the config
 533                 * rom to indicate that they are booting (for example,
 534                 * if the firmware is on the disk of a external
 535                 * harddisk).  In that case we just fail, and the
 536                 * retry mechanism will try again later.
 537                 */
 538                if (i == 0 && rom[i] == 0) {
 539                        ret = RCODE_BUSY;
 540                        goto out;
 541                }
 542        }
 543
 544        device->max_speed = device->node->max_speed;
 545
 546        /*
 547         * Determine the speed of
 548         *   - devices with link speed less than PHY speed,
 549         *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
 550         *   - all devices if there are 1394b repeaters.
 551         * Note, we cannot use the bus info block's link_spd as starting point
 552         * because some buggy firmwares set it lower than necessary and because
 553         * 1394-1995 nodes do not have the field.
 554         */
 555        if ((rom[2] & 0x7) < device->max_speed ||
 556            device->max_speed == SCODE_BETA ||
 557            card->beta_repeaters_present) {
 558                u32 dummy;
 559
 560                /* for S1600 and S3200 */
 561                if (device->max_speed == SCODE_BETA)
 562                        device->max_speed = card->link_speed;
 563
 564                while (device->max_speed > SCODE_100) {
 565                        if (read_rom(device, generation, 0, &dummy) ==
 566                            RCODE_COMPLETE)
 567                                break;
 568                        device->max_speed--;
 569                }
 570        }
 571
 572        /*
 573         * Now parse the config rom.  The config rom is a recursive
 574         * directory structure so we parse it using a stack of
 575         * references to the blocks that make up the structure.  We
 576         * push a reference to the root directory on the stack to
 577         * start things off.
 578         */
 579        length = i;
 580        sp = 0;
 581        stack[sp++] = 0xc0000005;
 582        while (sp > 0) {
 583                /*
 584                 * Pop the next block reference of the stack.  The
 585                 * lower 24 bits is the offset into the config rom,
 586                 * the upper 8 bits are the type of the reference the
 587                 * block.
 588                 */
 589                key = stack[--sp];
 590                i = key & 0xffffff;
 591                if (WARN_ON(i >= MAX_CONFIG_ROM_SIZE)) {
 592                        ret = -ENXIO;
 593                        goto out;
 594                }
 595
 596                /* Read header quadlet for the block to get the length. */
 597                ret = read_rom(device, generation, i, &rom[i]);
 598                if (ret != RCODE_COMPLETE)
 599                        goto out;
 600                end = i + (rom[i] >> 16) + 1;
 601                if (end > MAX_CONFIG_ROM_SIZE) {
 602                        /*
 603                         * This block extends outside the config ROM which is
 604                         * a firmware bug.  Ignore this whole block, i.e.
 605                         * simply set a fake block length of 0.
 606                         */
 607                        fw_err(card, "skipped invalid ROM block %x at %llx\n",
 608                               rom[i],
 609                               i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
 610                        rom[i] = 0;
 611                        end = i;
 612                }
 613                i++;
 614
 615                /*
 616                 * Now read in the block.  If this is a directory
 617                 * block, check the entries as we read them to see if
 618                 * it references another block, and push it in that case.
 619                 */
 620                for (; i < end; i++) {
 621                        ret = read_rom(device, generation, i, &rom[i]);
 622                        if (ret != RCODE_COMPLETE)
 623                                goto out;
 624
 625                        if ((key >> 30) != 3 || (rom[i] >> 30) < 2)
 626                                continue;
 627                        /*
 628                         * Offset points outside the ROM.  May be a firmware
 629                         * bug or an Extended ROM entry (IEEE 1212-2001 clause
 630                         * 7.7.18).  Simply overwrite this pointer here by a
 631                         * fake immediate entry so that later iterators over
 632                         * the ROM don't have to check offsets all the time.
 633                         */
 634                        if (i + (rom[i] & 0xffffff) >= MAX_CONFIG_ROM_SIZE) {
 635                                fw_err(card,
 636                                       "skipped unsupported ROM entry %x at %llx\n",
 637                                       rom[i],
 638                                       i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
 639                                rom[i] = 0;
 640                                continue;
 641                        }
 642                        stack[sp++] = i + rom[i];
 643                }
 644                if (length < i)
 645                        length = i;
 646        }
 647
 648        old_rom = device->config_rom;
 649        new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
 650        if (new_rom == NULL) {
 651                ret = -ENOMEM;
 652                goto out;
 653        }
 654
 655        down_write(&fw_device_rwsem);
 656        device->config_rom = new_rom;
 657        device->config_rom_length = length;
 658        up_write(&fw_device_rwsem);
 659
 660        kfree(old_rom);
 661        ret = RCODE_COMPLETE;
 662        device->max_rec = rom[2] >> 12 & 0xf;
 663        device->cmc     = rom[2] >> 30 & 1;
 664        device->irmc    = rom[2] >> 31 & 1;
 665 out:
 666        kfree(rom);
 667
 668        return ret;
 669}
 670
 671static void fw_unit_release(struct device *dev)
 672{
 673        struct fw_unit *unit = fw_unit(dev);
 674
 675        fw_device_put(fw_parent_device(unit));
 676        kfree(unit);
 677}
 678
 679static struct device_type fw_unit_type = {
 680        .uevent         = fw_unit_uevent,
 681        .release        = fw_unit_release,
 682};
 683
 684static bool is_fw_unit(struct device *dev)
 685{
 686        return dev->type == &fw_unit_type;
 687}
 688
 689static void create_units(struct fw_device *device)
 690{
 691        struct fw_csr_iterator ci;
 692        struct fw_unit *unit;
 693        int key, value, i;
 694
 695        i = 0;
 696        fw_csr_iterator_init(&ci, &device->config_rom[5]);
 697        while (fw_csr_iterator_next(&ci, &key, &value)) {
 698                if (key != (CSR_UNIT | CSR_DIRECTORY))
 699                        continue;
 700
 701                /*
 702                 * Get the address of the unit directory and try to
 703                 * match the drivers id_tables against it.
 704                 */
 705                unit = kzalloc(sizeof(*unit), GFP_KERNEL);
 706                if (unit == NULL)
 707                        continue;
 708
 709                unit->directory = ci.p + value - 1;
 710                unit->device.bus = &fw_bus_type;
 711                unit->device.type = &fw_unit_type;
 712                unit->device.parent = &device->device;
 713                dev_set_name(&unit->device, "%s.%d", dev_name(&device->device), i++);
 714
 715                BUILD_BUG_ON(ARRAY_SIZE(unit->attribute_group.attrs) <
 716                                ARRAY_SIZE(fw_unit_attributes) +
 717                                ARRAY_SIZE(config_rom_attributes));
 718                init_fw_attribute_group(&unit->device,
 719                                        fw_unit_attributes,
 720                                        &unit->attribute_group);
 721
 722                if (device_register(&unit->device) < 0)
 723                        goto skip_unit;
 724
 725                fw_device_get(device);
 726                continue;
 727
 728        skip_unit:
 729                kfree(unit);
 730        }
 731}
 732
 733static int shutdown_unit(struct device *device, void *data)
 734{
 735        device_unregister(device);
 736
 737        return 0;
 738}
 739
 740/*
 741 * fw_device_rwsem acts as dual purpose mutex:
 742 *   - serializes accesses to fw_device_idr,
 743 *   - serializes accesses to fw_device.config_rom/.config_rom_length and
 744 *     fw_unit.directory, unless those accesses happen at safe occasions
 745 */
 746DECLARE_RWSEM(fw_device_rwsem);
 747
 748DEFINE_IDR(fw_device_idr);
 749int fw_cdev_major;
 750
 751struct fw_device *fw_device_get_by_devt(dev_t devt)
 752{
 753        struct fw_device *device;
 754
 755        down_read(&fw_device_rwsem);
 756        device = idr_find(&fw_device_idr, MINOR(devt));
 757        if (device)
 758                fw_device_get(device);
 759        up_read(&fw_device_rwsem);
 760
 761        return device;
 762}
 763
 764struct workqueue_struct *fw_workqueue;
 765EXPORT_SYMBOL(fw_workqueue);
 766
 767static void fw_schedule_device_work(struct fw_device *device,
 768                                    unsigned long delay)
 769{
 770        queue_delayed_work(fw_workqueue, &device->work, delay);
 771}
 772
 773/*
 774 * These defines control the retry behavior for reading the config
 775 * rom.  It shouldn't be necessary to tweak these; if the device
 776 * doesn't respond to a config rom read within 10 seconds, it's not
 777 * going to respond at all.  As for the initial delay, a lot of
 778 * devices will be able to respond within half a second after bus
 779 * reset.  On the other hand, it's not really worth being more
 780 * aggressive than that, since it scales pretty well; if 10 devices
 781 * are plugged in, they're all getting read within one second.
 782 */
 783
 784#define MAX_RETRIES     10
 785#define RETRY_DELAY     (3 * HZ)
 786#define INITIAL_DELAY   (HZ / 2)
 787#define SHUTDOWN_DELAY  (2 * HZ)
 788
 789static void fw_device_shutdown(struct work_struct *work)
 790{
 791        struct fw_device *device =
 792                container_of(work, struct fw_device, work.work);
 793        int minor = MINOR(device->device.devt);
 794
 795        if (time_before64(get_jiffies_64(),
 796                          device->card->reset_jiffies + SHUTDOWN_DELAY)
 797            && !list_empty(&device->card->link)) {
 798                fw_schedule_device_work(device, SHUTDOWN_DELAY);
 799                return;
 800        }
 801
 802        if (atomic_cmpxchg(&device->state,
 803                           FW_DEVICE_GONE,
 804                           FW_DEVICE_SHUTDOWN) != FW_DEVICE_GONE)
 805                return;
 806
 807        fw_device_cdev_remove(device);
 808        device_for_each_child(&device->device, NULL, shutdown_unit);
 809        device_unregister(&device->device);
 810
 811        down_write(&fw_device_rwsem);
 812        idr_remove(&fw_device_idr, minor);
 813        up_write(&fw_device_rwsem);
 814
 815        fw_device_put(device);
 816}
 817
 818static void fw_device_release(struct device *dev)
 819{
 820        struct fw_device *device = fw_device(dev);
 821        struct fw_card *card = device->card;
 822        unsigned long flags;
 823
 824        /*
 825         * Take the card lock so we don't set this to NULL while a
 826         * FW_NODE_UPDATED callback is being handled or while the
 827         * bus manager work looks at this node.
 828         */
 829        spin_lock_irqsave(&card->lock, flags);
 830        device->node->data = NULL;
 831        spin_unlock_irqrestore(&card->lock, flags);
 832
 833        fw_node_put(device->node);
 834        kfree(device->config_rom);
 835        kfree(device);
 836        fw_card_put(card);
 837}
 838
 839static struct device_type fw_device_type = {
 840        .release = fw_device_release,
 841};
 842
 843static bool is_fw_device(struct device *dev)
 844{
 845        return dev->type == &fw_device_type;
 846}
 847
 848static int update_unit(struct device *dev, void *data)
 849{
 850        struct fw_unit *unit = fw_unit(dev);
 851        struct fw_driver *driver = (struct fw_driver *)dev->driver;
 852
 853        if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
 854                device_lock(dev);
 855                driver->update(unit);
 856                device_unlock(dev);
 857        }
 858
 859        return 0;
 860}
 861
 862static void fw_device_update(struct work_struct *work)
 863{
 864        struct fw_device *device =
 865                container_of(work, struct fw_device, work.work);
 866
 867        fw_device_cdev_update(device);
 868        device_for_each_child(&device->device, NULL, update_unit);
 869}
 870
 871/*
 872 * If a device was pending for deletion because its node went away but its
 873 * bus info block and root directory header matches that of a newly discovered
 874 * device, revive the existing fw_device.
 875 * The newly allocated fw_device becomes obsolete instead.
 876 */
 877static int lookup_existing_device(struct device *dev, void *data)
 878{
 879        struct fw_device *old = fw_device(dev);
 880        struct fw_device *new = data;
 881        struct fw_card *card = new->card;
 882        int match = 0;
 883
 884        if (!is_fw_device(dev))
 885                return 0;
 886
 887        down_read(&fw_device_rwsem); /* serialize config_rom access */
 888        spin_lock_irq(&card->lock);  /* serialize node access */
 889
 890        if (memcmp(old->config_rom, new->config_rom, 6 * 4) == 0 &&
 891            atomic_cmpxchg(&old->state,
 892                           FW_DEVICE_GONE,
 893                           FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
 894                struct fw_node *current_node = new->node;
 895                struct fw_node *obsolete_node = old->node;
 896
 897                new->node = obsolete_node;
 898                new->node->data = new;
 899                old->node = current_node;
 900                old->node->data = old;
 901
 902                old->max_speed = new->max_speed;
 903                old->node_id = current_node->node_id;
 904                smp_wmb();  /* update node_id before generation */
 905                old->generation = card->generation;
 906                old->config_rom_retries = 0;
 907                fw_notice(card, "rediscovered device %s\n", dev_name(dev));
 908
 909                old->workfn = fw_device_update;
 910                fw_schedule_device_work(old, 0);
 911
 912                if (current_node == card->root_node)
 913                        fw_schedule_bm_work(card, 0);
 914
 915                match = 1;
 916        }
 917
 918        spin_unlock_irq(&card->lock);
 919        up_read(&fw_device_rwsem);
 920
 921        return match;
 922}
 923
 924enum { BC_UNKNOWN = 0, BC_UNIMPLEMENTED, BC_IMPLEMENTED, };
 925
 926static void set_broadcast_channel(struct fw_device *device, int generation)
 927{
 928        struct fw_card *card = device->card;
 929        __be32 data;
 930        int rcode;
 931
 932        if (!card->broadcast_channel_allocated)
 933                return;
 934
 935        /*
 936         * The Broadcast_Channel Valid bit is required by nodes which want to
 937         * transmit on this channel.  Such transmissions are practically
 938         * exclusive to IP over 1394 (RFC 2734).  IP capable nodes are required
 939         * to be IRM capable and have a max_rec of 8 or more.  We use this fact
 940         * to narrow down to which nodes we send Broadcast_Channel updates.
 941         */
 942        if (!device->irmc || device->max_rec < 8)
 943                return;
 944
 945        /*
 946         * Some 1394-1995 nodes crash if this 1394a-2000 register is written.
 947         * Perform a read test first.
 948         */
 949        if (device->bc_implemented == BC_UNKNOWN) {
 950                rcode = fw_run_transaction(card, TCODE_READ_QUADLET_REQUEST,
 951                                device->node_id, generation, device->max_speed,
 952                                CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 953                                &data, 4);
 954                switch (rcode) {
 955                case RCODE_COMPLETE:
 956                        if (data & cpu_to_be32(1 << 31)) {
 957                                device->bc_implemented = BC_IMPLEMENTED;
 958                                break;
 959                        }
 960                        /* else, fall through - to case address error */
 961                case RCODE_ADDRESS_ERROR:
 962                        device->bc_implemented = BC_UNIMPLEMENTED;
 963                }
 964        }
 965
 966        if (device->bc_implemented == BC_IMPLEMENTED) {
 967                data = cpu_to_be32(BROADCAST_CHANNEL_INITIAL |
 968                                   BROADCAST_CHANNEL_VALID);
 969                fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
 970                                device->node_id, generation, device->max_speed,
 971                                CSR_REGISTER_BASE + CSR_BROADCAST_CHANNEL,
 972                                &data, 4);
 973        }
 974}
 975
 976int fw_device_set_broadcast_channel(struct device *dev, void *gen)
 977{
 978        if (is_fw_device(dev))
 979                set_broadcast_channel(fw_device(dev), (long)gen);
 980
 981        return 0;
 982}
 983
 984static void fw_device_init(struct work_struct *work)
 985{
 986        struct fw_device *device =
 987                container_of(work, struct fw_device, work.work);
 988        struct fw_card *card = device->card;
 989        struct device *revived_dev;
 990        int minor, ret;
 991
 992        /*
 993         * All failure paths here set node->data to NULL, so that we
 994         * don't try to do device_for_each_child() on a kfree()'d
 995         * device.
 996         */
 997
 998        ret = read_config_rom(device, device->generation);
 999        if (ret != RCODE_COMPLETE) {
1000                if (device->config_rom_retries < MAX_RETRIES &&
1001                    atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1002                        device->config_rom_retries++;
1003                        fw_schedule_device_work(device, RETRY_DELAY);
1004                } else {
1005                        if (device->node->link_on)
1006                                fw_notice(card, "giving up on node %x: reading config rom failed: %s\n",
1007                                          device->node_id,
1008                                          fw_rcode_string(ret));
1009                        if (device->node == card->root_node)
1010                                fw_schedule_bm_work(card, 0);
1011                        fw_device_release(&device->device);
1012                }
1013                return;
1014        }
1015
1016        revived_dev = device_find_child(card->device,
1017                                        device, lookup_existing_device);
1018        if (revived_dev) {
1019                put_device(revived_dev);
1020                fw_device_release(&device->device);
1021
1022                return;
1023        }
1024
1025        device_initialize(&device->device);
1026
1027        fw_device_get(device);
1028        down_write(&fw_device_rwsem);
1029        minor = idr_alloc(&fw_device_idr, device, 0, 1 << MINORBITS,
1030                        GFP_KERNEL);
1031        up_write(&fw_device_rwsem);
1032
1033        if (minor < 0)
1034                goto error;
1035
1036        device->device.bus = &fw_bus_type;
1037        device->device.type = &fw_device_type;
1038        device->device.parent = card->device;
1039        device->device.devt = MKDEV(fw_cdev_major, minor);
1040        dev_set_name(&device->device, "fw%d", minor);
1041
1042        BUILD_BUG_ON(ARRAY_SIZE(device->attribute_group.attrs) <
1043                        ARRAY_SIZE(fw_device_attributes) +
1044                        ARRAY_SIZE(config_rom_attributes));
1045        init_fw_attribute_group(&device->device,
1046                                fw_device_attributes,
1047                                &device->attribute_group);
1048
1049        if (device_add(&device->device)) {
1050                fw_err(card, "failed to add device\n");
1051                goto error_with_cdev;
1052        }
1053
1054        create_units(device);
1055
1056        /*
1057         * Transition the device to running state.  If it got pulled
1058         * out from under us while we did the initialization work, we
1059         * have to shut down the device again here.  Normally, though,
1060         * fw_node_event will be responsible for shutting it down when
1061         * necessary.  We have to use the atomic cmpxchg here to avoid
1062         * racing with the FW_NODE_DESTROYED case in
1063         * fw_node_event().
1064         */
1065        if (atomic_cmpxchg(&device->state,
1066                           FW_DEVICE_INITIALIZING,
1067                           FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
1068                device->workfn = fw_device_shutdown;
1069                fw_schedule_device_work(device, SHUTDOWN_DELAY);
1070        } else {
1071                fw_notice(card, "created device %s: GUID %08x%08x, S%d00\n",
1072                          dev_name(&device->device),
1073                          device->config_rom[3], device->config_rom[4],
1074                          1 << device->max_speed);
1075                device->config_rom_retries = 0;
1076
1077                set_broadcast_channel(device, device->generation);
1078
1079                add_device_randomness(&device->config_rom[3], 8);
1080        }
1081
1082        /*
1083         * Reschedule the IRM work if we just finished reading the
1084         * root node config rom.  If this races with a bus reset we
1085         * just end up running the IRM work a couple of extra times -
1086         * pretty harmless.
1087         */
1088        if (device->node == card->root_node)
1089                fw_schedule_bm_work(card, 0);
1090
1091        return;
1092
1093 error_with_cdev:
1094        down_write(&fw_device_rwsem);
1095        idr_remove(&fw_device_idr, minor);
1096        up_write(&fw_device_rwsem);
1097 error:
1098        fw_device_put(device);          /* fw_device_idr's reference */
1099
1100        put_device(&device->device);    /* our reference */
1101}
1102
1103/* Reread and compare bus info block and header of root directory */
1104static int reread_config_rom(struct fw_device *device, int generation,
1105                             bool *changed)
1106{
1107        u32 q;
1108        int i, rcode;
1109
1110        for (i = 0; i < 6; i++) {
1111                rcode = read_rom(device, generation, i, &q);
1112                if (rcode != RCODE_COMPLETE)
1113                        return rcode;
1114
1115                if (i == 0 && q == 0)
1116                        /* inaccessible (see read_config_rom); retry later */
1117                        return RCODE_BUSY;
1118
1119                if (q != device->config_rom[i]) {
1120                        *changed = true;
1121                        return RCODE_COMPLETE;
1122                }
1123        }
1124
1125        *changed = false;
1126        return RCODE_COMPLETE;
1127}
1128
1129static void fw_device_refresh(struct work_struct *work)
1130{
1131        struct fw_device *device =
1132                container_of(work, struct fw_device, work.work);
1133        struct fw_card *card = device->card;
1134        int ret, node_id = device->node_id;
1135        bool changed;
1136
1137        ret = reread_config_rom(device, device->generation, &changed);
1138        if (ret != RCODE_COMPLETE)
1139                goto failed_config_rom;
1140
1141        if (!changed) {
1142                if (atomic_cmpxchg(&device->state,
1143                                   FW_DEVICE_INITIALIZING,
1144                                   FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1145                        goto gone;
1146
1147                fw_device_update(work);
1148                device->config_rom_retries = 0;
1149                goto out;
1150        }
1151
1152        /*
1153         * Something changed.  We keep things simple and don't investigate
1154         * further.  We just destroy all previous units and create new ones.
1155         */
1156        device_for_each_child(&device->device, NULL, shutdown_unit);
1157
1158        ret = read_config_rom(device, device->generation);
1159        if (ret != RCODE_COMPLETE)
1160                goto failed_config_rom;
1161
1162        fw_device_cdev_update(device);
1163        create_units(device);
1164
1165        /* Userspace may want to re-read attributes. */
1166        kobject_uevent(&device->device.kobj, KOBJ_CHANGE);
1167
1168        if (atomic_cmpxchg(&device->state,
1169                           FW_DEVICE_INITIALIZING,
1170                           FW_DEVICE_RUNNING) == FW_DEVICE_GONE)
1171                goto gone;
1172
1173        fw_notice(card, "refreshed device %s\n", dev_name(&device->device));
1174        device->config_rom_retries = 0;
1175        goto out;
1176
1177 failed_config_rom:
1178        if (device->config_rom_retries < MAX_RETRIES &&
1179            atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
1180                device->config_rom_retries++;
1181                fw_schedule_device_work(device, RETRY_DELAY);
1182                return;
1183        }
1184
1185        fw_notice(card, "giving up on refresh of device %s: %s\n",
1186                  dev_name(&device->device), fw_rcode_string(ret));
1187 gone:
1188        atomic_set(&device->state, FW_DEVICE_GONE);
1189        device->workfn = fw_device_shutdown;
1190        fw_schedule_device_work(device, SHUTDOWN_DELAY);
1191 out:
1192        if (node_id == card->root_node->node_id)
1193                fw_schedule_bm_work(card, 0);
1194}
1195
1196static void fw_device_workfn(struct work_struct *work)
1197{
1198        struct fw_device *device = container_of(to_delayed_work(work),
1199                                                struct fw_device, work);
1200        device->workfn(work);
1201}
1202
1203void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
1204{
1205        struct fw_device *device;
1206
1207        switch (event) {
1208        case FW_NODE_CREATED:
1209                /*
1210                 * Attempt to scan the node, regardless whether its self ID has
1211                 * the L (link active) flag set or not.  Some broken devices
1212                 * send L=0 but have an up-and-running link; others send L=1
1213                 * without actually having a link.
1214                 */
1215 create:
1216                device = kzalloc(sizeof(*device), GFP_ATOMIC);
1217                if (device == NULL)
1218                        break;
1219
1220                /*
1221                 * Do minimal initialization of the device here, the
1222                 * rest will happen in fw_device_init().
1223                 *
1224                 * Attention:  A lot of things, even fw_device_get(),
1225                 * cannot be done before fw_device_init() finished!
1226                 * You can basically just check device->state and
1227                 * schedule work until then, but only while holding
1228                 * card->lock.
1229                 */
1230                atomic_set(&device->state, FW_DEVICE_INITIALIZING);
1231                device->card = fw_card_get(card);
1232                device->node = fw_node_get(node);
1233                device->node_id = node->node_id;
1234                device->generation = card->generation;
1235                device->is_local = node == card->local_node;
1236                mutex_init(&device->client_list_mutex);
1237                INIT_LIST_HEAD(&device->client_list);
1238
1239                /*
1240                 * Set the node data to point back to this device so
1241                 * FW_NODE_UPDATED callbacks can update the node_id
1242                 * and generation for the device.
1243                 */
1244                node->data = device;
1245
1246                /*
1247                 * Many devices are slow to respond after bus resets,
1248                 * especially if they are bus powered and go through
1249                 * power-up after getting plugged in.  We schedule the
1250                 * first config rom scan half a second after bus reset.
1251                 */
1252                device->workfn = fw_device_init;
1253                INIT_DELAYED_WORK(&device->work, fw_device_workfn);
1254                fw_schedule_device_work(device, INITIAL_DELAY);
1255                break;
1256
1257        case FW_NODE_INITIATED_RESET:
1258        case FW_NODE_LINK_ON:
1259                device = node->data;
1260                if (device == NULL)
1261                        goto create;
1262
1263                device->node_id = node->node_id;
1264                smp_wmb();  /* update node_id before generation */
1265                device->generation = card->generation;
1266                if (atomic_cmpxchg(&device->state,
1267                            FW_DEVICE_RUNNING,
1268                            FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
1269                        device->workfn = fw_device_refresh;
1270                        fw_schedule_device_work(device,
1271                                device->is_local ? 0 : INITIAL_DELAY);
1272                }
1273                break;
1274
1275        case FW_NODE_UPDATED:
1276                device = node->data;
1277                if (device == NULL)
1278                        break;
1279
1280                device->node_id = node->node_id;
1281                smp_wmb();  /* update node_id before generation */
1282                device->generation = card->generation;
1283                if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
1284                        device->workfn = fw_device_update;
1285                        fw_schedule_device_work(device, 0);
1286                }
1287                break;
1288
1289        case FW_NODE_DESTROYED:
1290        case FW_NODE_LINK_OFF:
1291                if (!node->data)
1292                        break;
1293
1294                /*
1295                 * Destroy the device associated with the node.  There
1296                 * are two cases here: either the device is fully
1297                 * initialized (FW_DEVICE_RUNNING) or we're in the
1298                 * process of reading its config rom
1299                 * (FW_DEVICE_INITIALIZING).  If it is fully
1300                 * initialized we can reuse device->work to schedule a
1301                 * full fw_device_shutdown().  If not, there's work
1302                 * scheduled to read it's config rom, and we just put
1303                 * the device in shutdown state to have that code fail
1304                 * to create the device.
1305                 */
1306                device = node->data;
1307                if (atomic_xchg(&device->state,
1308                                FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
1309                        device->workfn = fw_device_shutdown;
1310                        fw_schedule_device_work(device,
1311                                list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
1312                }
1313                break;
1314        }
1315}
1316