fw-device.c

linux 内核源代码

		 * 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;
	}
}