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

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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: Daniel Baluta <daniel.baluta@nxp.com>
Acked-by: Arnaud 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: Rob Herring (Arm) <robh@kernel.org>
This commit is contained in:
Rob Herring (Arm) 2025-04-23 14:42:13 -05:00
parent 67dd139c91
commit f4fcfdda2f
2 changed files with 106 additions and 0 deletions
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80
drivers/of/of_reserved_mem.c
View File

@ -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);

26
include/linux/of_reserved_mem.h
View File

@ -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
/**