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fw-device.c

/*
 * Device probing and sysfs code.
 *
 * Copyright (C) 2005-2006  Kristian Hoegsberg <krh@bitplanet.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/module.h>
#include <linux/wait.h>
#include <linux/errno.h>
#include <linux/kthread.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/idr.h>
#include <linux/rwsem.h>
#include <asm/semaphore.h>
#include <linux/ctype.h>
#include "fw-transaction.h"
#include "fw-topology.h"
#include "fw-device.h"

void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
{
      ci->p = p + 1;
      ci->end = ci->p + (p[0] >> 16);
}
EXPORT_SYMBOL(fw_csr_iterator_init);

int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
{
      *key = *ci->p >> 24;
      *value = *ci->p & 0xffffff;

      return ci->p++ < ci->end;
}
EXPORT_SYMBOL(fw_csr_iterator_next);

static int is_fw_unit(struct device *dev);

static int match_unit_directory(u32 * directory, const struct fw_device_id *id)
{
      struct fw_csr_iterator ci;
      int key, value, match;

      match = 0;
      fw_csr_iterator_init(&ci, directory);
      while (fw_csr_iterator_next(&ci, &key, &value)) {
            if (key == CSR_VENDOR && value == id->vendor)
                  match |= FW_MATCH_VENDOR;
            if (key == CSR_MODEL && value == id->model)
                  match |= FW_MATCH_MODEL;
            if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
                  match |= FW_MATCH_SPECIFIER_ID;
            if (key == CSR_VERSION && value == id->version)
                  match |= FW_MATCH_VERSION;
      }

      return (match & id->match_flags) == id->match_flags;
}

static int fw_unit_match(struct device *dev, struct device_driver *drv)
{
      struct fw_unit *unit = fw_unit(dev);
      struct fw_driver *driver = fw_driver(drv);
      int i;

      /* We only allow binding to fw_units. */
      if (!is_fw_unit(dev))
            return 0;

      for (i = 0; driver->id_table[i].match_flags != 0; i++) {
            if (match_unit_directory(unit->directory, &driver->id_table[i]))
                  return 1;
      }

      return 0;
}

static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
{
      struct fw_device *device = fw_device(unit->device.parent);
      struct fw_csr_iterator ci;

      int key, value;
      int vendor = 0;
      int model = 0;
      int specifier_id = 0;
      int version = 0;

      fw_csr_iterator_init(&ci, &device->config_rom[5]);
      while (fw_csr_iterator_next(&ci, &key, &value)) {
            switch (key) {
            case CSR_VENDOR:
                  vendor = value;
                  break;
            case CSR_MODEL:
                  model = value;
                  break;
            }
      }

      fw_csr_iterator_init(&ci, unit->directory);
      while (fw_csr_iterator_next(&ci, &key, &value)) {
            switch (key) {
            case CSR_SPECIFIER_ID:
                  specifier_id = value;
                  break;
            case CSR_VERSION:
                  version = value;
                  break;
            }
      }

      return snprintf(buffer, buffer_size,
                  "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
                  vendor, model, specifier_id, version);
}

static int
fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
{
      struct fw_unit *unit = fw_unit(dev);
      char modalias[64];

      get_modalias(unit, modalias, sizeof(modalias));

      if (add_uevent_var(env, "MODALIAS=%s", modalias))
            return -ENOMEM;

      return 0;
}

struct bus_type fw_bus_type = {
      .name = "firewire",
      .match = fw_unit_match,
};
EXPORT_SYMBOL(fw_bus_type);

struct fw_device *fw_device_get(struct fw_device *device)
{
      get_device(&device->device);

      return device;
}

void fw_device_put(struct fw_device *device)
{
      put_device(&device->device);
}

static void fw_device_release(struct device *dev)
{
      struct fw_device *device = fw_device(dev);
      unsigned long flags;

      /*
       * Take the card lock so we don't set this to NULL while a
       * FW_NODE_UPDATED callback is being handled.
       */
      spin_lock_irqsave(&device->card->lock, flags);
      device->node->data = NULL;
      spin_unlock_irqrestore(&device->card->lock, flags);

      fw_node_put(device->node);
      fw_card_put(device->card);
      kfree(device->config_rom);
      kfree(device);
}

int fw_device_enable_phys_dma(struct fw_device *device)
{
      return device->card->driver->enable_phys_dma(device->card,
                                         device->node_id,
                                         device->generation);
}
EXPORT_SYMBOL(fw_device_enable_phys_dma);

struct config_rom_attribute {
      struct device_attribute attr;
      u32 key;
};

static ssize_t
show_immediate(struct device *dev, struct device_attribute *dattr, char *buf)
{
      struct config_rom_attribute *attr =
            container_of(dattr, struct config_rom_attribute, attr);
      struct fw_csr_iterator ci;
      u32 *dir;
      int key, value;

      if (is_fw_unit(dev))
            dir = fw_unit(dev)->directory;
      else
            dir = fw_device(dev)->config_rom + 5;

      fw_csr_iterator_init(&ci, dir);
      while (fw_csr_iterator_next(&ci, &key, &value))
            if (attr->key == key)
                  return snprintf(buf, buf ? PAGE_SIZE : 0,
                              "0x%06x\n", value);

      return -ENOENT;
}

#define IMMEDIATE_ATTR(name, key)                     \
      { __ATTR(name, S_IRUGO, show_immediate, NULL), key }

static ssize_t
show_text_leaf(struct device *dev, struct device_attribute *dattr, char *buf)
{
      struct config_rom_attribute *attr =
            container_of(dattr, struct config_rom_attribute, attr);
      struct fw_csr_iterator ci;
      u32 *dir, *block = NULL, *p, *end;
      int length, key, value, last_key = 0;
      char *b;

      if (is_fw_unit(dev))
            dir = fw_unit(dev)->directory;
      else
            dir = fw_device(dev)->config_rom + 5;

      fw_csr_iterator_init(&ci, dir);
      while (fw_csr_iterator_next(&ci, &key, &value)) {
            if (attr->key == last_key &&
                key == (CSR_DESCRIPTOR | CSR_LEAF))
                  block = ci.p - 1 + value;
            last_key = key;
      }

      if (block == NULL)
            return -ENOENT;

      length = min(block[0] >> 16, 256U);
      if (length < 3)
            return -ENOENT;

      if (block[1] != 0 || block[2] != 0)
            /* Unknown encoding. */
            return -ENOENT;

      if (buf == NULL)
            return length * 4;

      b = buf;
      end = &block[length + 1];
      for (p = &block[3]; p < end; p++, b += 4)
            * (u32 *) b = (__force u32) __cpu_to_be32(*p);

      /* Strip trailing whitespace and add newline. */
      while (b--, (isspace(*b) || *b == '\0') && b > buf);
      strcpy(b + 1, "\n");

      return b + 2 - buf;
}

#define TEXT_LEAF_ATTR(name, key)                     \
      { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }

static struct config_rom_attribute config_rom_attributes[] = {
      IMMEDIATE_ATTR(vendor, CSR_VENDOR),
      IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
      IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
      IMMEDIATE_ATTR(version, CSR_VERSION),
      IMMEDIATE_ATTR(model, CSR_MODEL),
      TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
      TEXT_LEAF_ATTR(model_name, CSR_MODEL),
      TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
};

static void
init_fw_attribute_group(struct device *dev,
                  struct device_attribute *attrs,
                  struct fw_attribute_group *group)
{
      struct device_attribute *attr;
      int i, j;

      for (j = 0; attrs[j].attr.name != NULL; j++)
            group->attrs[j] = &attrs[j].attr;

      for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
            attr = &config_rom_attributes[i].attr;
            if (attr->show(dev, attr, NULL) < 0)
                  continue;
            group->attrs[j++] = &attr->attr;
      }

      BUG_ON(j >= ARRAY_SIZE(group->attrs));
      group->attrs[j++] = NULL;
      group->groups[0] = &group->group;
      group->groups[1] = NULL;
      group->group.attrs = group->attrs;
      dev->groups = group->groups;
}

static ssize_t
modalias_show(struct device *dev,
            struct device_attribute *attr, char *buf)
{
      struct fw_unit *unit = fw_unit(dev);
      int length;

      length = get_modalias(unit, buf, PAGE_SIZE);
      strcpy(buf + length, "\n");

      return length + 1;
}

static ssize_t
rom_index_show(struct device *dev,
             struct device_attribute *attr, char *buf)
{
      struct fw_device *device = fw_device(dev->parent);
      struct fw_unit *unit = fw_unit(dev);

      return snprintf(buf, PAGE_SIZE, "%d\n",
                  (int)(unit->directory - device->config_rom));
}

static struct device_attribute fw_unit_attributes[] = {
      __ATTR_RO(modalias),
      __ATTR_RO(rom_index),
      __ATTR_NULL,
};

static ssize_t
config_rom_show(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct fw_device *device = fw_device(dev);

      memcpy(buf, device->config_rom, device->config_rom_length * 4);

      return device->config_rom_length * 4;
}

static ssize_t
guid_show(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct fw_device *device = fw_device(dev);
      u64 guid;

      guid = ((u64)device->config_rom[3] << 32) | device->config_rom[4];

      return snprintf(buf, PAGE_SIZE, "0x%016llx\n",
                  (unsigned long long)guid);
}

static struct device_attribute fw_device_attributes[] = {
      __ATTR_RO(config_rom),
      __ATTR_RO(guid),
      __ATTR_NULL,
};

struct read_quadlet_callback_data {
      struct completion done;
      int rcode;
      u32 data;
};

static void
complete_transaction(struct fw_card *card, int rcode,
                 void *payload, size_t length, void *data)
{
      struct read_quadlet_callback_data *callback_data = data;

      if (rcode == RCODE_COMPLETE)
            callback_data->data = be32_to_cpu(*(__be32 *)payload);
      callback_data->rcode = rcode;
      complete(&callback_data->done);
}

static int read_rom(struct fw_device *device, int index, u32 * data)
{
      struct read_quadlet_callback_data callback_data;
      struct fw_transaction t;
      u64 offset;

      init_completion(&callback_data.done);

      offset = 0xfffff0000400ULL + index * 4;
      fw_send_request(device->card, &t, TCODE_READ_QUADLET_REQUEST,
                  device->node_id, device->generation, device->max_speed,
                  offset, NULL, 4, complete_transaction, &callback_data);

      wait_for_completion(&callback_data.done);

      *data = callback_data.data;

      return callback_data.rcode;
}

static int read_bus_info_block(struct fw_device *device)
{
      static u32 rom[256];
      u32 stack[16], sp, key;
      int i, end, length;

      device->max_speed = SCODE_100;

      /* First read the bus info block. */
      for (i = 0; i < 5; i++) {
            if (read_rom(device, i, &rom[i]) != RCODE_COMPLETE)
                  return -1;
            /*
             * As per IEEE1212 7.2, during power-up, devices can
             * reply with a 0 for the first quadlet of the config
             * rom to indicate that they are booting (for example,
             * if the firmware is on the disk of a external
             * harddisk).  In that case we just fail, and the
             * retry mechanism will try again later.
             */
            if (i == 0 && rom[i] == 0)
                  return -1;
      }

      device->max_speed = device->node->max_speed;

      /*
       * Determine the speed of
       *   - devices with link speed less than PHY speed,
       *   - devices with 1394b PHY (unless only connected to 1394a PHYs),
       *   - all devices if there are 1394b repeaters.
       * Note, we cannot use the bus info block's link_spd as starting point
       * because some buggy firmwares set it lower than necessary and because
       * 1394-1995 nodes do not have the field.
       */
      if ((rom[2] & 0x7) < device->max_speed ||
          device->max_speed == SCODE_BETA ||
          device->card->beta_repeaters_present) {
            u32 dummy;

            /* for S1600 and S3200 */
            if (device->max_speed == SCODE_BETA)
                  device->max_speed = device->card->link_speed;

            while (device->max_speed > SCODE_100) {
                  if (read_rom(device, 0, &dummy) == RCODE_COMPLETE)
                        break;
                  device->max_speed--;
            }
      }

      /*
       * Now parse the config rom.  The config rom is a recursive
       * directory structure so we parse it using a stack of
       * references to the blocks that make up the structure.  We
       * push a reference to the root directory on the stack to
       * start things off.
       */
      length = i;
      sp = 0;
      stack[sp++] = 0xc0000005;
      while (sp > 0) {
            /*
             * Pop the next block reference of the stack.  The
             * lower 24 bits is the offset into the config rom,
             * the upper 8 bits are the type of the reference the
             * block.
             */
            key = stack[--sp];
            i = key & 0xffffff;
            if (i >= ARRAY_SIZE(rom))
                  /*
                   * The reference points outside the standard
                   * config rom area, something's fishy.
                   */
                  return -1;

            /* Read header quadlet for the block to get the length. */
            if (read_rom(device, i, &rom[i]) != RCODE_COMPLETE)
                  return -1;
            end = i + (rom[i] >> 16) + 1;
            i++;
            if (end > ARRAY_SIZE(rom))
                  /*
                   * This block extends outside standard config
                   * area (and the array we're reading it
                   * into).  That's broken, so ignore this
                   * device.
                   */
                  return -1;

            /*
             * Now read in the block.  If this is a directory
             * block, check the entries as we read them to see if
             * it references another block, and push it in that case.
             */
            while (i < end) {
                  if (read_rom(device, i, &rom[i]) != RCODE_COMPLETE)
                        return -1;
                  if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
                      sp < ARRAY_SIZE(stack))
                        stack[sp++] = i + rom[i];
                  i++;
            }
            if (length < i)
                  length = i;
      }

      device->config_rom = kmalloc(length * 4, GFP_KERNEL);
      if (device->config_rom == NULL)
            return -1;
      memcpy(device->config_rom, rom, length * 4);
      device->config_rom_length = length;

      return 0;
}

static void fw_unit_release(struct device *dev)
{
      struct fw_unit *unit = fw_unit(dev);

      kfree(unit);
}

static struct device_type fw_unit_type = {
      .uevent           = fw_unit_uevent,
      .release    = fw_unit_release,
};

static int is_fw_unit(struct device *dev)
{
      return dev->type == &fw_unit_type;
}

static void create_units(struct fw_device *device)
{
      struct fw_csr_iterator ci;
      struct fw_unit *unit;
      int key, value, i;

      i = 0;
      fw_csr_iterator_init(&ci, &device->config_rom[5]);
      while (fw_csr_iterator_next(&ci, &key, &value)) {
            if (key != (CSR_UNIT | CSR_DIRECTORY))
                  continue;

            /*
             * Get the address of the unit directory and try to
             * match the drivers id_tables against it.
             */
            unit = kzalloc(sizeof(*unit), GFP_KERNEL);
            if (unit == NULL) {
                  fw_error("failed to allocate memory for unit\n");
                  continue;
            }

            unit->directory = ci.p + value - 1;
            unit->device.bus = &fw_bus_type;
            unit->device.type = &fw_unit_type;
            unit->device.parent = &device->device;
            snprintf(unit->device.bus_id, sizeof(unit->device.bus_id),
                   "%s.%d", device->device.bus_id, i++);

            init_fw_attribute_group(&unit->device,
                              fw_unit_attributes,
                              &unit->attribute_group);
            if (device_register(&unit->device) < 0)
                  goto skip_unit;

            continue;

      skip_unit:
            kfree(unit);
      }
}

static int shutdown_unit(struct device *device, void *data)
{
      device_unregister(device);

      return 0;
}

static DECLARE_RWSEM(idr_rwsem);
static DEFINE_IDR(fw_device_idr);
int fw_cdev_major;

struct fw_device *fw_device_from_devt(dev_t devt)
{
      struct fw_device *device;

      down_read(&idr_rwsem);
      device = idr_find(&fw_device_idr, MINOR(devt));
      up_read(&idr_rwsem);

      return device;
}

static void fw_device_shutdown(struct work_struct *work)
{
      struct fw_device *device =
            container_of(work, struct fw_device, work.work);
      int minor = MINOR(device->device.devt);

      down_write(&idr_rwsem);
      idr_remove(&fw_device_idr, minor);
      up_write(&idr_rwsem);

      fw_device_cdev_remove(device);
      device_for_each_child(&device->device, NULL, shutdown_unit);
      device_unregister(&device->device);
}

static struct device_type fw_device_type = {
      .release    = fw_device_release,
};

/*
 * These defines control the retry behavior for reading the config
 * rom.  It shouldn't be necessary to tweak these; if the device
 * doesn't respond to a config rom read within 10 seconds, it's not
 * going to respond at all.  As for the initial delay, a lot of
 * devices will be able to respond within half a second after bus
 * reset.  On the other hand, it's not really worth being more
 * aggressive than that, since it scales pretty well; if 10 devices
 * are plugged in, they're all getting read within one second.
 */

#define MAX_RETRIES     10
#define RETRY_DELAY     (3 * HZ)
#define INITIAL_DELAY   (HZ / 2)

static void fw_device_init(struct work_struct *work)
{
      struct fw_device *device =
            container_of(work, struct fw_device, work.work);
      int minor, err;

      /*
       * All failure paths here set node->data to NULL, so that we
       * don't try to do device_for_each_child() on a kfree()'d
       * device.
       */

      if (read_bus_info_block(device) < 0) {
            if (device->config_rom_retries < MAX_RETRIES) {
                  device->config_rom_retries++;
                  schedule_delayed_work(&device->work, RETRY_DELAY);
            } else {
                  fw_notify("giving up on config rom for node id %x\n",
                          device->node_id);
                  if (device->node == device->card->root_node)
                        schedule_delayed_work(&device->card->work, 0);
                  fw_device_release(&device->device);
            }
            return;
      }

      err = -ENOMEM;
      down_write(&idr_rwsem);
      if (idr_pre_get(&fw_device_idr, GFP_KERNEL))
            err = idr_get_new(&fw_device_idr, device, &minor);
      up_write(&idr_rwsem);
      if (err < 0)
            goto error;

      device->device.bus = &fw_bus_type;
      device->device.type = &fw_device_type;
      device->device.parent = device->card->device;
      device->device.devt = MKDEV(fw_cdev_major, minor);
      snprintf(device->device.bus_id, sizeof(device->device.bus_id),
             "fw%d", minor);

      init_fw_attribute_group(&device->device,
                        fw_device_attributes,
                        &device->attribute_group);
      if (device_add(&device->device)) {
            fw_error("Failed to add device.\n");
            goto error_with_cdev;
      }

      create_units(device);

      /*
       * Transition the device to running state.  If it got pulled
       * out from under us while we did the intialization work, we
       * have to shut down the device again here.  Normally, though,
       * fw_node_event will be responsible for shutting it down when
       * necessary.  We have to use the atomic cmpxchg here to avoid
       * racing with the FW_NODE_DESTROYED case in
       * fw_node_event().
       */
      if (atomic_cmpxchg(&device->state,
                FW_DEVICE_INITIALIZING,
                FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
            fw_device_shutdown(&device->work.work);
      else
            fw_notify("created new fw device %s "
                    "(%d config rom retries, S%d00)\n",
                    device->device.bus_id, device->config_rom_retries,
                    1 << device->max_speed);

      /*
       * Reschedule the IRM work if we just finished reading the
       * root node config rom.  If this races with a bus reset we
       * just end up running the IRM work a couple of extra times -
       * pretty harmless.
       */
      if (device->node == device->card->root_node)
            schedule_delayed_work(&device->card->work, 0);

      return;

 error_with_cdev:
      down_write(&idr_rwsem);
      idr_remove(&fw_device_idr, minor);
      up_write(&idr_rwsem);
 error:
      put_device(&device->device);
}

static int update_unit(struct device *dev, void *data)
{
      struct fw_unit *unit = fw_unit(dev);
      struct fw_driver *driver = (struct fw_driver *)dev->driver;

      if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
            down(&dev->sem);
            driver->update(unit);
            up(&dev->sem);
      }

      return 0;
}

static void fw_device_update(struct work_struct *work)
{
      struct fw_device *device =
            container_of(work, struct fw_device, work.work);

      fw_device_cdev_update(device);
      device_for_each_child(&device->device, NULL, update_unit);
}

void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
{
      struct fw_device *device;

      switch (event) {
      case FW_NODE_CREATED:
      case FW_NODE_LINK_ON:
            if (!node->link_on)
                  break;

            device = kzalloc(sizeof(*device), GFP_ATOMIC);
            if (device == NULL)
                  break;

            /*
             * Do minimal intialization of the device here, the
             * rest will happen in fw_device_init().  We need the
             * card and node so we can read the config rom and we
             * need to do device_initialize() now so
             * device_for_each_child() in FW_NODE_UPDATED is
             * doesn't freak out.
             */
            device_initialize(&device->device);
            atomic_set(&device->state, FW_DEVICE_INITIALIZING);
            device->card = fw_card_get(card);
            device->node = fw_node_get(node);
            device->node_id = node->node_id;
            device->generation = card->generation;
            INIT_LIST_HEAD(&device->client_list);

            /*
             * Set the node data to point back to this device so
             * FW_NODE_UPDATED callbacks can update the node_id
             * and generation for the device.
             */
            node->data = device;

            /*
             * Many devices are slow to respond after bus resets,
             * especially if they are bus powered and go through
             * power-up after getting plugged in.  We schedule the
             * first config rom scan half a second after bus reset.
             */
            INIT_DELAYED_WORK(&device->work, fw_device_init);
            schedule_delayed_work(&device->work, INITIAL_DELAY);
            break;

      case FW_NODE_UPDATED:
            if (!node->link_on || node->data == NULL)
                  break;

            device = node->data;
            device->node_id = node->node_id;
            device->generation = card->generation;
            if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
                  PREPARE_DELAYED_WORK(&device->work, fw_device_update);
                  schedule_delayed_work(&device->work, 0);
            }
            break;

      case FW_NODE_DESTROYED:
      case FW_NODE_LINK_OFF:
            if (!node->data)
                  break;

            /*
             * Destroy the device associated with the node.  There
             * are two cases here: either the device is fully
             * initialized (FW_DEVICE_RUNNING) or we're in the
             * process of reading its config rom
             * (FW_DEVICE_INITIALIZING).  If it is fully
             * initialized we can reuse device->work to schedule a
             * full fw_device_shutdown().  If not, there's work
             * scheduled to read it's config rom, and we just put
             * the device in shutdown state to have that code fail
             * to create the device.
             */
            device = node->data;
            if (atomic_xchg(&device->state,
                        FW_DEVICE_SHUTDOWN) == FW_DEVICE_RUNNING) {
                  PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
                  schedule_delayed_work(&device->work, 0);
            }
            break;
      }
}

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