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resources: Add device-managed request/release_resource()

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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: Thierry Reding <treding@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Thierry Reding 2014-08-01 14:15:10 +02:00 committed by Bjorn Helgaas
parent 52addcf9d6
commit 8d38821cbc
3 changed files with 77 additions and 0 deletions
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2
Documentation/driver-model/devres.txt
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@ -264,8 +264,10 @@ IIO
IO region IO region
devm_release_mem_region() devm_release_mem_region()
devm_release_region() devm_release_region()
devm_release_resource()
devm_request_mem_region() devm_request_mem_region()
devm_request_region() devm_request_region()
devm_request_resource()
IOMAP IOMAP
devm_ioport_map() devm_ioport_map()

5
include/linux/ioport.h
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@ -215,6 +215,11 @@ static inline int __deprecated check_region(resource_size_t s,
/* Wrappers for managed devices */ /* Wrappers for managed devices */
struct device; 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) \ #define devm_request_region(dev,start,n,name) \
__devm_request_region(dev, &ioport_resource, (start), (n), (name)) __devm_request_region(dev, &ioport_resource, (start), (n), (name))
#define devm_request_mem_region(dev,start,n,name) \ #define devm_request_mem_region(dev,start,n,name) \

70
kernel/resource.c
View File

@ -1248,6 +1248,76 @@ int release_mem_region_adjustable(struct resource *parent,
/* /*
* Managed region resource * 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 region_devres {
struct resource *parent; struct resource *parent;
resource_size_t start; resource_size_t start;