[PATCH] AGP fix for Xen VMM

When Linux is running on the Xen virtual machine monitor, physical
addresses are virtualised and cannot be directly referenced by the AGP
GART.  This patch fixes the GART driver for Xen by adding a layer of
abstraction between physical addresses and 'GART addresses'.

Architecture-specific functions are also defined for allocating and freeing
the GATT.  Xen requires this to ensure that table really is contiguous from
the point of view of the GART.

These extra interface functions are defined as 'no-ops' for all existing
architectures that use the GART driver.

Signed-off-by: Keir Fraser <keir@xensource.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>

7 files changed, 70 insertions, 0 deletions

diff --git a/include/asm-alpha/agp.h b/include/asm-alpha/agp.h
index c99dbbb..ef855a3 100644
--- a/include/asm-alpha/agp.h
+++ b/include/asm-alpha/agp.h
@@ -10,4 +10,14 @@
 #define flush_agp_mappings() 
 #define flush_agp_cache() mb()
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif
diff --git a/include/asm-i386/agp.h b/include/asm-i386/agp.h
index a917ff5..b82f5f3 100644
--- a/include/asm-i386/agp.h
+++ b/include/asm-i386/agp.h
@@ -21,4 +21,14 @@ int unmap_page_from_agp(struct page *page);
    worth it. Would need a page for it. */
 #define flush_agp_cache() asm volatile("wbinvd":::"memory")
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif
diff --git a/include/asm-ia64/agp.h b/include/asm-ia64/agp.h
index d1316f1..4e517f0 100644
--- a/include/asm-ia64/agp.h
+++ b/include/asm-ia64/agp.h
@@ -18,4 +18,14 @@
 #define flush_agp_mappings()		/* nothing */
 #define flush_agp_cache()		mb()
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif /* _ASM_IA64_AGP_H */
diff --git a/include/asm-ppc/agp.h b/include/asm-ppc/agp.h
index be27cfa8..ca9e423 100644
--- a/include/asm-ppc/agp.h
+++ b/include/asm-ppc/agp.h
@@ -10,4 +10,14 @@
 #define flush_agp_mappings()
 #define flush_agp_cache() mb()
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif
diff --git a/include/asm-ppc64/agp.h b/include/asm-ppc64/agp.h
index be27cfa8..ca9e423 100644
--- a/include/asm-ppc64/agp.h
+++ b/include/asm-ppc64/agp.h
@@ -10,4 +10,14 @@
 #define flush_agp_mappings()
 #define flush_agp_cache() mb()
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif
diff --git a/include/asm-sparc64/agp.h b/include/asm-sparc64/agp.h
index ba05bdf..58f8cb6 100644
--- a/include/asm-sparc64/agp.h
+++ b/include/asm-sparc64/agp.h
@@ -8,4 +8,14 @@
 #define flush_agp_mappings() 
 #define flush_agp_cache() mb()
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif
diff --git a/include/asm-x86_64/agp.h b/include/asm-x86_64/agp.h
index 0bb9019..06c52ee 100644
--- a/include/asm-x86_64/agp.h
+++ b/include/asm-x86_64/agp.h
@@ -19,4 +19,14 @@ int unmap_page_from_agp(struct page *page);
    worth it. Would need a page for it. */
 #define flush_agp_cache() asm volatile("wbinvd":::"memory")
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif