Commit f3fd0c8a authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI: Allow ACPI handles of devices to be initialized in advance 



Currently, the ACPI handles of devices are initialized from within
device_add(), by acpi_bind_one() called from acpi_platform_notify()
which first uses the .find_device() routine provided by the device's
bus type to find the matching device node in the ACPI namespace.
This is a source of some computational overhead and, moreover, the
correctness of the result depends on the implementation of
.find_device() which is known to fail occasionally for some bus types
(e.g. PCI).  In some cases, however, the corresponding ACPI device
node is known already before calling device_add() for the given
struct device object and the whole .find_device() dance in
acpi_platform_notify() is then simply unnecessary.

For this reason, make it possible to initialize the ACPI handles of
devices before calling device_add() for them.  Modify
acpi_platform_notify() to call acpi_bind_one() in advance to check
the device's existing ACPI handle and skip the .find_device()
search if that is successful.  Change acpi_bind_one() accordingly.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
parent 8a66790b

drivers/acpi/glue.c

+34 −10
Original line number Diff line number Diff line
@@ -130,45 +130,58 @@ static int acpi_bind_one(struct device *dev, acpi_handle handle) 
{

	struct acpi_device *acpi_dev;

	acpi_status status;

	struct acpi_device_physical_node *physical_node;

	struct acpi_device_physical_node *physical_node, *pn;

	char physical_node_name[sizeof(PHYSICAL_NODE_STRING) + 2];

	int retval = -EINVAL;



	if (dev->acpi_handle) {

		dev_warn(dev, "Drivers changed 'acpi_handle'\n");

		if (handle) {

			dev_warn(dev, "ACPI handle is already set\n");

			return -EINVAL;

		} else {

			handle = dev->acpi_handle;

		}

	}

	if (!handle)

		return -EINVAL;



	get_device(dev);

	status = acpi_bus_get_device(handle, &acpi_dev);

	if (ACPI_FAILURE(status))

		goto err;



	physical_node = kzalloc(sizeof(struct acpi_device_physical_node),

		GFP_KERNEL);

	physical_node = kzalloc(sizeof(*physical_node), GFP_KERNEL);

	if (!physical_node) {

		retval = -ENOMEM;

		goto err;

	}



	mutex_lock(&acpi_dev->physical_node_lock);



	/* Sanity check. */

	list_for_each_entry(pn, &acpi_dev->physical_node_list, node)

		if (pn->dev == dev) {

			dev_warn(dev, "Already associated with ACPI node\n");

			goto err_free;

		}



	/* allocate physical node id according to physical_node_id_bitmap */

	physical_node->node_id =

		find_first_zero_bit(acpi_dev->physical_node_id_bitmap,

		ACPI_MAX_PHYSICAL_NODE);

	if (physical_node->node_id >= ACPI_MAX_PHYSICAL_NODE) {

		retval = -ENOSPC;

		mutex_unlock(&acpi_dev->physical_node_lock);

		kfree(physical_node);

		goto err;

		goto err_free;

	}



	set_bit(physical_node->node_id, acpi_dev->physical_node_id_bitmap);

	physical_node->dev = dev;

	list_add_tail(&physical_node->node, &acpi_dev->physical_node_list);

	acpi_dev->physical_node_count++;



	mutex_unlock(&acpi_dev->physical_node_lock);



	if (!dev->acpi_handle)

		dev->acpi_handle = handle;



	if (!physical_node->node_id)
@@ -187,8 +200,14 @@ static int acpi_bind_one(struct device *dev, acpi_handle handle) 
	return 0;



 err:

	dev->acpi_handle = NULL;

	put_device(dev);

	return retval;



 err_free:

	mutex_unlock(&acpi_dev->physical_node_lock);

	kfree(physical_node);

	goto err;

}



static int acpi_unbind_one(struct device *dev)
@@ -247,6 +266,10 @@ static int acpi_platform_notify(struct device *dev) 
	acpi_handle handle;

	int ret = -EINVAL;



	ret = acpi_bind_one(dev, NULL);

	if (!ret)

		goto out;



	if (!dev->bus || !dev->parent) {

		/* bridge devices genernally haven't bus or parent */

		ret = acpi_find_bridge_device(dev, &handle);
@@ -264,6 +287,7 @@ static int acpi_platform_notify(struct device *dev) 
	if (!ret)

		acpi_bind_one(dev, handle);



 out:

#if ACPI_GLUE_DEBUG

	if (!ret) {

		struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

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