Commit-ID: 9fd126bc742f74a95d2ba610247712ff05da02fe
Gitweb: http://git.kernel.org/tip/9fd126bc742f74a95d2ba610247712ff05da02fe
Author: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
AuthorDate: Fri, 10 Jul 2009 09:57:34 -0700
Committer: H. Peter Anvin <hpa@xxxxxxxxx>
CommitDate: Wed, 26 Aug 2009 15:41:10 -0700
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@xxxxxxxxx>
Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
---
arch/x86/include/asm/pat.h | 5 ++++
arch/x86/mm/pat.c | 49 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 54 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/pat.h b/arch/x86/include/asm/pat.h
index 7af14e5..e2c1668 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 */
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index d5af279..82d097c 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -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)
{
--
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