Commit eb297bc7 authored by Bjorn Andersson's avatar Bjorn Andersson Committed by Andy Gross
Browse files

of: reserved_mem: Accessor for acquiring reserved_mem 



In some cases drivers referencing a reserved-memory region might want to
remap the entire region, but when defining the reserved-memory by "size"
the client driver has no means to know the associated base address of
the reserved memory region.

This patch adds an accessor for such drivers to acquire a handle to
their associated reserved-memory for this purpose.

A complicating factor for the implementation is that the reserved_mem
objects are created from the flattened DeviceTree, as such we can't
use the device_node address for comparison. Fortunately the name of the
node will be used as "name" of the reserved_mem and will be used when
building the full_name, so we can compare the "name" with the basename
of the full_name to find the match.

Reviewed-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: default avatarAndy Gross <andy.gross@linaro.org>
parent a50ff19d

drivers/of/of_reserved_mem.c

+26 −0
Original line number Diff line number Diff line
@@ -397,3 +397,29 @@ void of_reserved_mem_device_release(struct device *dev) 
	rmem->ops->device_release(rmem, dev);

}

EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);



/**

 * of_reserved_mem_lookup() - acquire reserved_mem from a device node

 * @np:		node pointer of the desired reserved-memory region

 *

 * This function allows drivers to acquire a reference to the reserved_mem

 * struct based on a device node handle.

 *

 * Returns a reserved_mem reference, or NULL on error.

 */

struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)

{

	const char *name;

	int i;



	if (!np->full_name)

		return NULL;



	name = kbasename(np->full_name);

	for (i = 0; i < reserved_mem_count; i++)

		if (!strcmp(reserved_mem[i].name, name))

			return &reserved_mem[i];



	return NULL;

}

EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);

include/linux/of_reserved_mem.h

+5 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ int early_init_dt_alloc_reserved_memory_arch(phys_addr_t size, 
void fdt_init_reserved_mem(void);

void fdt_reserved_mem_save_node(unsigned long node, const char *uname,

			       phys_addr_t base, phys_addr_t size);

struct reserved_mem *of_reserved_mem_lookup(struct device_node *np);

#else

static inline int of_reserved_mem_device_init_by_idx(struct device *dev,

					struct device_node *np, int idx)
@@ -55,6 +56,10 @@ static inline void of_reserved_mem_device_release(struct device *pdev) { } 
static inline void fdt_init_reserved_mem(void) { }

static inline void fdt_reserved_mem_save_node(unsigned long node,

		const char *uname, phys_addr_t base, phys_addr_t size) { }

static inline struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)

{

	return NULL;

}

#endif



/**

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