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Commit 8d38821c authored by Thierry Reding's avatar Thierry Reding Committed by Bjorn Helgaas
Browse files

resources: Add device-managed request/release_resource() 



Provide device-managed implementations of the request_resource() and
release_resource() functions.  Upon failure to request a resource, the new
devm_request_resource() function will output an error message for
consistent error reporting.

Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
parent 52addcf9

Documentation/driver-model/devres.txt

+2 −0
Original line number Diff line number Diff line
@@ -264,8 +264,10 @@ IIO 
IO region

  devm_release_mem_region()

  devm_release_region()

  devm_release_resource()

  devm_request_mem_region()

  devm_request_region()

  devm_request_resource()



IOMAP

  devm_ioport_map()

include/linux/ioport.h

+5 −0
Original line number Diff line number Diff line
@@ -215,6 +215,11 @@ static inline int __deprecated check_region(resource_size_t s, 


/* Wrappers for managed devices */

struct device;



extern int devm_request_resource(struct device *dev, struct resource *root,

				 struct resource *new);

extern void devm_release_resource(struct device *dev, struct resource *new);



#define devm_request_region(dev,start,n,name) \

	__devm_request_region(dev, &ioport_resource, (start), (n), (name))

#define devm_request_mem_region(dev,start,n,name) \

kernel/resource.c

+70 −0
Original line number Diff line number Diff line
@@ -1248,6 +1248,76 @@ int release_mem_region_adjustable(struct resource *parent, 
/*

 * Managed region resource

 */

static void devm_resource_release(struct device *dev, void *ptr)

{

	struct resource **r = ptr;



	release_resource(*r);

}



/**

 * devm_request_resource() - request and reserve an I/O or memory resource

 * @dev: device for which to request the resource

 * @root: root of the resource tree from which to request the resource

 * @new: descriptor of the resource to request

 *

 * This is a device-managed version of request_resource(). There is usually

 * no need to release resources requested by this function explicitly since

 * that will be taken care of when the device is unbound from its driver.

 * If for some reason the resource needs to be released explicitly, because

 * of ordering issues for example, drivers must call devm_release_resource()

 * rather than the regular release_resource().

 *

 * When a conflict is detected between any existing resources and the newly

 * requested resource, an error message will be printed.

 *

 * Returns 0 on success or a negative error code on failure.

 */

int devm_request_resource(struct device *dev, struct resource *root,

			  struct resource *new)

{

	struct resource *conflict, **ptr;



	ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);

	if (!ptr)

		return -ENOMEM;



	*ptr = new;



	conflict = request_resource_conflict(root, new);

	if (conflict) {

		dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",

			new, conflict->name, conflict);

		devres_free(ptr);

		return -EBUSY;

	}



	devres_add(dev, ptr);

	return 0;

}

EXPORT_SYMBOL(devm_request_resource);



static int devm_resource_match(struct device *dev, void *res, void *data)

{

	struct resource **ptr = res;



	return *ptr == data;

}



/**

 * devm_release_resource() - release a previously requested resource

 * @dev: device for which to release the resource

 * @new: descriptor of the resource to release

 *

 * Releases a resource previously requested using devm_request_resource().

 */

void devm_release_resource(struct device *dev, struct resource *new)

{

	WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,

			       new));

}

EXPORT_SYMBOL(devm_release_resource);



struct region_devres {

	struct resource *parent;

	resource_size_t start;