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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: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Venkatesh Pallipadi 2009-07-10 09:57:34 -07:00 committed by H. Peter Anvin
parent 279e669b3f
commit 9fd126bc74
2 changed files with 54 additions and 0 deletions
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5
arch/x86/include/asm/pat.h
View File

@ -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 */

49
arch/x86/mm/pat.c
View File

@ -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)
{