Skip to content

Commit

Permalink
[PATCH] swiotlb: support syncing DMA_BIDIRECTIONAL mappings
Browse files Browse the repository at this point in the history 
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: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
  • Loading branch information
John W. Linville authored and Tony Luck committed Sep 29, 2005
1 parent 878a97c commit de69e0f
Showing 1 changed file with 40 additions and 22 deletions.
62 changes: 40 additions & 22 deletions lib/swiotlb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;

/*
Expand Down Expand Up @@ -397,21 +405,28 @@ 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)
memcpy(buffer, dma_addr, size);
else if (dir == DMA_TO_DEVICE)
memcpy(dma_addr, buffer, size);
else
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)
BUG();
break;
case SYNC_FOR_DEVICE:
if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
memcpy(dma_addr, buffer, size);
else if (dir != DMA_FROM_DEVICE)
BUG();
break;
default:
BUG();
}
}

void *
Expand Down Expand Up @@ -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);
}
Expand All @@ -612,29 +627,30 @@ 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);
}

/*
* Same as above, but for a sub-range of the mapping.
*/
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);
}
Expand All @@ -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);
}

/*
Expand Down Expand Up @@ -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;

Expand All @@ -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
Expand Down

0 comments on commit de69e0f

Please sign in to comment.