Commit 72f8c0bf authored by Wolfram Sang's avatar Wolfram Sang Committed by Greg Kroah-Hartman
Browse files

lib: devres: add convenience function to remap a resource 



Almost every platform_driver does the three steps get_resource,
request_mem_region, ioremap. This does not only lead to a lot of code
duplication, but also a huge number of similar error strings and
inconsistent error codes on failure. So, introduce a helper function
which simplifies remapping a resource and make it hard to do something
wrong and add documentation for it.

Signed-off-by: default avatarWolfram Sang <w.sang@pengutronix.de>
Acked-by: default avatarGrant Likely <grant.likely@secretlab.ca>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 571806a9

Documentation/driver-model/devres.txt

+1 −0
Original line number Diff line number Diff line
@@ -262,6 +262,7 @@ IOMAP 
  devm_ioremap()

  devm_ioremap_nocache()

  devm_iounmap()

  devm_request_and_ioremap() : checks resource, requests region, ioremaps

  pcim_iomap()

  pcim_iounmap()

  pcim_iomap_table()	: array of mapped addresses indexed by BAR

include/linux/device.h

+3 −0
Original line number Diff line number Diff line
@@ -490,6 +490,9 @@ extern int devres_release_group(struct device *dev, void *id); 
extern void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp);

extern void devm_kfree(struct device *dev, void *p);



void __iomem *devm_request_and_ioremap(struct device *dev,

			struct resource *res);



struct device_dma_parameters {

	/*

	 * a low level driver may set these to teach IOMMU code about

lib/devres.c

+51 −0
Original line number Diff line number Diff line
@@ -85,6 +85,57 @@ void devm_iounmap(struct device *dev, void __iomem *addr) 
}

EXPORT_SYMBOL(devm_iounmap);



/**

 * devm_request_and_ioremap() - Check, request region, and ioremap resource

 * @dev: Generic device to handle the resource for

 * @res: resource to be handled

 *

 * Takes all necessary steps to ioremap a mem resource. Uses managed device, so

 * everything is undone on driver detach. Checks arguments, so you can feed

 * it the result from e.g. platform_get_resource() directly. Returns the

 * remapped pointer or NULL on error. Usage example:

 *

 *	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

 *	base = devm_request_and_ioremap(&pdev->dev, res);

 *	if (!base)

 *		return -EADDRNOTAVAIL;

 */

void __iomem *devm_request_and_ioremap(struct device *dev,

			struct resource *res)

{

	resource_size_t size;

	const char *name;

	void __iomem *dest_ptr;



	BUG_ON(!dev);



	if (!res || resource_type(res) != IORESOURCE_MEM) {

		dev_err(dev, "invalid resource\n");

		return NULL;

	}



	size = resource_size(res);

	name = res->name ?: dev_name(dev);



	if (!devm_request_mem_region(dev, res->start, size, name)) {

		dev_err(dev, "can't request region for resource %pR\n", res);

		return NULL;

	}



	if (res->flags & IORESOURCE_CACHEABLE)

		dest_ptr = devm_ioremap(dev, res->start, size);

	else

		dest_ptr = devm_ioremap_nocache(dev, res->start, size);



	if (!dest_ptr) {

		dev_err(dev, "ioremap failed for resource %pR\n", res);

		devm_release_mem_region(dev, res->start, size);

	}



	return dest_ptr;

}

EXPORT_SYMBOL(devm_request_and_ioremap);



#ifdef CONFIG_HAS_IOPORT

/*

 * Generic iomap devres

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