Commit f4fcfdda authored by Rob Herring (Arm)'s avatar Rob Herring (Arm)
Browse files

of: reserved_mem: Add functions to parse "memory-region" 



Drivers with "memory-region" properties currently have to do their own
parsing of "memory-region" properties. The result is all the drivers
have similar patterns of a call to parse "memory-region" and then get
the region's address and size. As this is a standard property, it should
have common functions for drivers to use. Add new functions to count the
number of regions and retrieve the region's address as a resource.

Reviewed-by: default avatarDaniel Baluta <daniel.baluta@nxp.com>
Acked-by: default avatarArnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/20250423-dt-memory-region-v2-v2-1-2fbd6ebd3c88@kernel.org


Signed-off-by: default avatarRob Herring (Arm) <robh@kernel.org>
parent 67dd139c

drivers/of/of_reserved_mem.c

+80 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#define pr_fmt(fmt)	"OF: reserved mem: " fmt



#include <linux/err.h>

#include <linux/ioport.h>

#include <linux/libfdt.h>

#include <linux/of.h>

#include <linux/of_fdt.h>
@@ -740,3 +741,82 @@ struct reserved_mem *of_reserved_mem_lookup(struct device_node *np) 
	return NULL;

}

EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);



/**

 * of_reserved_mem_region_to_resource() - Get a reserved memory region as a resource

 * @np:		node containing 'memory-region' property

 * @idx:	index of 'memory-region' property to lookup

 * @res:	Pointer to a struct resource to fill in with reserved region

 *

 * This function allows drivers to lookup a node's 'memory-region' property

 * entries by index and return a struct resource for the entry.

 *

 * Returns 0 on success with @res filled in. Returns -ENODEV if 'memory-region'

 * is missing or unavailable, -EINVAL for any other error.

 */

int of_reserved_mem_region_to_resource(const struct device_node *np,

				       unsigned int idx, struct resource *res)

{

	struct reserved_mem *rmem;



	if (!np)

		return -EINVAL;



	struct device_node __free(device_node) *target = of_parse_phandle(np, "memory-region", idx);

	if (!target || !of_device_is_available(target))

		return -ENODEV;



	rmem = of_reserved_mem_lookup(target);

	if (!rmem)

		return -EINVAL;



	resource_set_range(res, rmem->base, rmem->size);

	res->name = rmem->name;

	return 0;

}

EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource);



/**

 * of_reserved_mem_region_to_resource_byname() - Get a reserved memory region as a resource

 * @np:		node containing 'memory-region' property

 * @name:	name of 'memory-region' property entry to lookup

 * @res:	Pointer to a struct resource to fill in with reserved region

 *

 * This function allows drivers to lookup a node's 'memory-region' property

 * entries by name and return a struct resource for the entry.

 *

 * Returns 0 on success with @res filled in, or a negative error-code on

 * failure.

 */

int of_reserved_mem_region_to_resource_byname(const struct device_node *np,

					      const char *name,

					      struct resource *res)

{

	int idx;



	if (!name)

		return -EINVAL;



	idx = of_property_match_string(np, "memory-region-names", name);

	if (idx < 0)

		return idx;



	return of_reserved_mem_region_to_resource(np, idx, res);

}

EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource_byname);



/**

 * of_reserved_mem_region_count() - Return the number of 'memory-region' entries

 * @np:		node containing 'memory-region' property

 *

 * This function allows drivers to retrieve the number of entries for a node's

 * 'memory-region' property.

 *

 * Returns the number of entries on success, or negative error code on a

 * malformed property.

 */

int of_reserved_mem_region_count(const struct device_node *np)

{

	return of_count_phandle_with_args(np, "memory-region", NULL);

}

EXPORT_SYMBOL_GPL(of_reserved_mem_region_count);

include/linux/of_reserved_mem.h

+26 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 


struct of_phandle_args;

struct reserved_mem_ops;

struct resource;



struct reserved_mem {

	const char			*name;
@@ -39,6 +40,12 @@ int of_reserved_mem_device_init_by_name(struct device *dev, 
void of_reserved_mem_device_release(struct device *dev);



struct reserved_mem *of_reserved_mem_lookup(struct device_node *np);

int of_reserved_mem_region_to_resource(const struct device_node *np,

				       unsigned int idx, struct resource *res);

int of_reserved_mem_region_to_resource_byname(const struct device_node *np,

					      const char *name, struct resource *res);

int of_reserved_mem_region_count(const struct device_node *np);



#else



#define RESERVEDMEM_OF_DECLARE(name, compat, init)			\
@@ -63,6 +70,25 @@ static inline struct reserved_mem *of_reserved_mem_lookup(struct device_node *np 
{

	return NULL;

}



static inline int of_reserved_mem_region_to_resource(const struct device_node *np,

						     unsigned int idx,

						     struct resource *res)

{

	return -ENOSYS;

}



static inline int of_reserved_mem_region_to_resource_byname(const struct device_node *np,

							    const char *name,

							    struct resource *res)

{

	return -ENOSYS;

}



static inline int of_reserved_mem_region_count(const struct device_node *np)

{

	return 0;

}

#endif



/**