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-rw-r--r--include/asm-i386/agp.h24
1 files changed, 24 insertions, 0 deletions
diff --git a/include/asm-i386/agp.h b/include/asm-i386/agp.h
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index 000000000000..a917ff50354f
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+++ b/include/asm-i386/agp.h
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+#ifndef AGP_H
+#define AGP_H 1
+
+#include <asm/pgtable.h>
+#include <asm/cacheflush.h>
+
+/*
+ * Functions to keep the agpgart mappings coherent with the MMU.
+ * The GART gives the CPU a physical alias of pages in memory. The alias region is
+ * mapped uncacheable. Make sure there are no conflicting mappings
+ * with different cachability attributes for the same page. This avoids
+ * data corruption on some CPUs.
+ */
+
+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() asm volatile("wbinvd":::"memory")
+
+#endif