linux/x86-64: missing agp.h

This causes data corruption and/or crashes when AGP is actually used.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

linux-2.6-xen-sparse/include/asm-x86_64/mach-xen/asm/agp.h

@@ -0,0 +1,35 @@
+#ifndef AGP_H
+#define AGP_H 1
+
+#include <asm/cacheflush.h>
+#include <asm/system.h>
+
+/*
+ * Functions to keep the agpgart mappings coherent.
+ * The GART gives the CPU a physical alias of memory. The alias is
+ * mapped uncacheable. Make sure there are no conflicting mappings
+ * with different cachability attributes for the same page.
+ */
+
+int map_page_into_agp(struct page *page);
+int unmap_page_from_agp(struct page *page);
+#define flush_agp_mappings() global_flush_tlb()
+
+/* Could use CLFLUSH here if the cpu supports it. But then it would
+   need to be called for each cacheline of the whole page so it may not be
+   worth it. Would need a page for it. */
+#define flush_agp_cache() wbinvd()
+
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) phys_to_machine(x)
+#define gart_to_phys(x) machine_to_phys(x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)	({                                          \
+	char *_t; dma_addr_t _d;                                            \
+	_t = dma_alloc_coherent(NULL,PAGE_SIZE<<(order),&_d,GFP_KERNEL);    \
+	_t; })
+#define free_gatt_pages(table, order)	\
+	dma_free_coherent(NULL,PAGE_SIZE<<(order),(table),virt_to_bus(table))
+
+#endif