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Commit 9fd126bc authored by Venkatesh Pallipadi's avatar Venkatesh Pallipadi Committed by H. Peter Anvin
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x86, pat: New i/f for driver to request memtype for IO regions 



Add new routines to request memtype for IO regions. This will currently
be a backend for io_mapping_* routines. But, it can also be made available
to drivers directly in future, in case it is needed.

reserve interface reserves the memory, makes sure we have a compatible
memory type available and keeps the identity map in sync when needed.

Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 279e669b

arch/x86/include/asm/pat.h

+5 −0
Original line number Diff line number Diff line
@@ -19,4 +19,9 @@ extern int free_memtype(u64 start, u64 end); 
extern int kernel_map_sync_memtype(u64 base, unsigned long size,

		unsigned long flag);



int io_reserve_memtype(resource_size_t start, resource_size_t end,

			unsigned long *type);



void io_free_memtype(resource_size_t start, resource_size_t end);



#endif /* _ASM_X86_PAT_H */

arch/x86/mm/pat.c

+49 −0
Original line number Diff line number Diff line
@@ -498,6 +498,55 @@ int free_memtype(u64 start, u64 end) 
}





/**

 * io_reserve_memtype - Request a memory type mapping for a region of memory

 * @start: start (physical address) of the region

 * @end: end (physical address) of the region

 * @type: A pointer to memtype, with requested type. On success, requested

 * or any other compatible type that was available for the region is returned

 *

 * On success, returns 0

 * On failure, returns non-zero

 */

int io_reserve_memtype(resource_size_t start, resource_size_t end,

			unsigned long *type)

{

	unsigned long req_type = *type;

	unsigned long new_type;

	int ret;



	WARN_ON_ONCE(iomem_map_sanity_check(start, end - start));



	ret = reserve_memtype(start, end, req_type, &new_type);

	if (ret)

		goto out_err;



	if (!is_new_memtype_allowed(req_type, new_type))

		goto out_free;



	if (kernel_map_sync_memtype(start, end - start, new_type) < 0)

		goto out_free;



	*type = new_type;

	return 0;



out_free:

	free_memtype(start, end);

	ret = -EBUSY;

out_err:

	return ret;

}



/**

 * io_free_memtype - Release a memory type mapping for a region of memory

 * @start: start (physical address) of the region

 * @end: end (physical address) of the region

 */

void io_free_memtype(resource_size_t start, resource_size_t end)

{

	free_memtype(start, end);

}



pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,

				unsigned long size, pgprot_t vma_prot)

{