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Commit de69e0f0 authored by John W. Linville's avatar John W. Linville Committed by Tony Luck
Browse files

[PATCH] swiotlb: support syncing DMA_BIDIRECTIONAL mappings 



The current implementation of sync_single in swiotlb.c chokes on
DMA_BIDIRECTIONAL mappings. This patch adds the capability to sync
those mappings, and optimizes other syncs by accounting for the
sync target (i.e. cpu or device) in addition to the DMA direction of
the mapping.

Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent 878a97cf

lib/swiotlb.c

+40 −22
Original line number Diff line number Diff line
@@ -58,6 +58,14 @@ 
 */

#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)



/*

 * Enumeration for sync targets

 */

enum dma_sync_target {

	SYNC_FOR_CPU = 0,

	SYNC_FOR_DEVICE = 1,

};



int swiotlb_force;



/*
@@ -397,22 +405,29 @@ unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir) 
}



static void

sync_single(struct device *hwdev, char *dma_addr, size_t size, int dir)

sync_single(struct device *hwdev, char *dma_addr, size_t size,

	    int dir, int target)

{

	int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;

	char *buffer = io_tlb_orig_addr[index];



	/*

	 * bounce... copy the data back into/from the original buffer

	 * XXX How do you handle DMA_BIDIRECTIONAL here ?

	 */

	if (dir == DMA_FROM_DEVICE)

	switch (target) {

	case SYNC_FOR_CPU:

		if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))

			memcpy(buffer, dma_addr, size);

	else if (dir == DMA_TO_DEVICE)

		else if (dir != DMA_TO_DEVICE)

			BUG();

		break;

	case SYNC_FOR_DEVICE:

		if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))

			memcpy(dma_addr, buffer, size);

	else

		else if (dir != DMA_FROM_DEVICE)

			BUG();

		break;

	default:

		BUG();

	}

}



void *

swiotlb_alloc_coherent(struct device *hwdev, size_t size,
@@ -596,14 +611,14 @@ swiotlb_unmap_single(struct device *hwdev, dma_addr_t dev_addr, size_t size, 
 */

static inline void

swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,

		    size_t size, int dir)

		    size_t size, int dir, int target)

{

	char *dma_addr = phys_to_virt(dev_addr);



	if (dir == DMA_NONE)

		BUG();

	if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)

		sync_single(hwdev, dma_addr, size, dir);

		sync_single(hwdev, dma_addr, size, dir, target);

	else if (dir == DMA_FROM_DEVICE)

		mark_clean(dma_addr, size);

}
@@ -612,14 +627,14 @@ void 
swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,

			    size_t size, int dir)

{

	swiotlb_sync_single(hwdev, dev_addr, size, dir);

	swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);

}



void

swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,

			       size_t size, int dir)

{

	swiotlb_sync_single(hwdev, dev_addr, size, dir);

	swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);

}



/*
@@ -627,14 +642,15 @@ swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr, 
 */

static inline void

swiotlb_sync_single_range(struct device *hwdev, dma_addr_t dev_addr,

			  unsigned long offset, size_t size, int dir)

			  unsigned long offset, size_t size,

			  int dir, int target)

{

	char *dma_addr = phys_to_virt(dev_addr) + offset;



	if (dir == DMA_NONE)

		BUG();

	if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)

		sync_single(hwdev, dma_addr, size, dir);

		sync_single(hwdev, dma_addr, size, dir, target);

	else if (dir == DMA_FROM_DEVICE)

		mark_clean(dma_addr, size);

}
@@ -643,14 +659,16 @@ void 
swiotlb_sync_single_range_for_cpu(struct device *hwdev, dma_addr_t dev_addr,

				  unsigned long offset, size_t size, int dir)

{

	swiotlb_sync_single_range(hwdev, dev_addr, offset, size, dir);

	swiotlb_sync_single_range(hwdev, dev_addr, offset, size, dir,

				  SYNC_FOR_CPU);

}



void

swiotlb_sync_single_range_for_device(struct device *hwdev, dma_addr_t dev_addr,

				     unsigned long offset, size_t size, int dir)

{

	swiotlb_sync_single_range(hwdev, dev_addr, offset, size, dir);

	swiotlb_sync_single_range(hwdev, dev_addr, offset, size, dir,

				  SYNC_FOR_DEVICE);

}



/*
@@ -729,7 +747,7 @@ swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nelems, 
 */

static inline void

swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sg,

		int nelems, int dir)

		int nelems, int dir, int target)

{

	int i;
@@ -739,21 +757,21 @@ swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sg, 
	for (i = 0; i < nelems; i++, sg++)

		if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))

			sync_single(hwdev, (void *) sg->dma_address,

				    sg->dma_length, dir);

				    sg->dma_length, dir, target);

}



void

swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,

			int nelems, int dir)

{

	swiotlb_sync_sg(hwdev, sg, nelems, dir);

	swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);

}



void

swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,

			   int nelems, int dir)

{

	swiotlb_sync_sg(hwdev, sg, nelems, dir);

	swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);

}



int