[PATCH] x86_64: Use function pointers to call DMA mapping functions

AK: I hacked Muli's original patch a lot and there were a lot
of changes - all bugs are probably to blame on me now.
There were also some changes in the fall back behaviour
for swiotlb - in particular it doesn't try to use GFP_DMA
now anymore. Also all DMA mapping operations use the
same core dma_alloc_coherent code with proper fallbacks now.
And various other changes and cleanups.

Known problems: iommu=force swiotlb=force together breaks
                needs more testing.

This patch cleans up x86_64's DMA mapping dispatching code. Right now
we have three possible IOMMU types: AGP GART, swiotlb and nommu, and
in the future we will also have Xen's x86_64 swiotlb and other HW
IOMMUs for x86_64. In order to support all of them cleanly, this
patch:

- introduces a struct dma_mapping_ops with function pointers for each
  of the DMA mapping operations of gart (AMD HW IOMMU), swiotlb
  (software IOMMU) and nommu (no IOMMU).

- gets rid of:

  if (swiotlb)
      return swiotlb_xxx();

- PCI_DMA_BUS_IS_PHYS is now checked against the dma_ops being set
This makes swiotlb faster by avoiding double copying in some cases.

Signed-Off-By: Muli Ben-Yehuda <mulix@mulix.org>
Signed-Off-By: Jon D. Mason <jdmason@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 11 insertions, 5 deletions

diff --git a/include/asm-x86_64/swiotlb.h b/include/asm-x86_64/swiotlb.h
index dddf1b218681..60757efd1353 100644
--- a/include/asm-x86_64/swiotlb.h
+++ b/include/asm-x86_64/swiotlb.h
@@ -3,10 +3,14 @@
 
 #include <linux/config.h>
 
+#include <asm/dma-mapping.h>
+
 /* SWIOTLB interface */
 
-extern dma_addr_t swiotlb_map_single(struct device *hwdev, void *ptr, size_t size,
-                                      int dir);
+extern dma_addr_t swiotlb_map_single(struct device *hwdev, void *ptr,
+                                     size_t size, int dir);
+extern void *swiotlb_alloc_coherent(struct device *hwdev, size_t size,
+                       dma_addr_t *dma_handle, gfp_t flags);
 extern void swiotlb_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
                                   size_t size, int dir);
 extern void swiotlb_sync_single_for_cpu(struct device *hwdev,
@@ -34,10 +38,10 @@ extern int swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg,
 extern void swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg,
                          int nents, int direction);
 extern int swiotlb_dma_mapping_error(dma_addr_t dma_addr);
-extern void *swiotlb_alloc_coherent (struct device *hwdev, size_t size,
-                                     dma_addr_t *dma_handle, gfp_t flags);
 extern void swiotlb_free_coherent (struct device *hwdev, size_t size,
                                    void *vaddr, dma_addr_t dma_handle);
+extern int swiotlb_dma_supported(struct device *hwdev, u64 mask);
+extern void swiotlb_init(void);
 
 #ifdef CONFIG_SWIOTLB
 extern int swiotlb;
@@ -45,4 +49,6 @@ extern int swiotlb;
 #define swiotlb 0
 #endif
 
-#endif
+extern void pci_swiotlb_init(void);
+
+#endif /* _ASM_SWTIOLB_H */