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>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/x86/include/asm/pat.h b/arch/x86/include/asm/pat.h
index 7af14e512f97..e2c1668dde7a 100644
--- a/arch/x86/include/asm/pat.h
+++ b/arch/x86/include/asm/pat.h
@@ -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 */