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ARC: dma: implement dma_unmap_page and sg variant

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Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta 2017-07-18 12:14:09 -07:00
parent b37174d95b
commit 2e332fec2f
1 changed files with 45 additions and 0 deletions
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45
arch/arc/mm/dma.c
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@ -153,6 +153,19 @@ static void _dma_cache_sync(phys_addr_t paddr, size_t size,
}
}
/*
* arc_dma_map_page - map a portion of a page for streaming DMA
*
* Ensure that any data held in the cache is appropriately discarded
* or written back.
*
* The device owns this memory once this call has completed. The CPU
* can regain ownership by calling dma_unmap_page().
*
* Note: while it takes struct page as arg, caller can "abuse" it to pass
* a region larger than PAGE_SIZE, provided it is physically contiguous
* and this still works correctly
*/
static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir,
unsigned long attrs)
@ -165,6 +178,24 @@ static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
return plat_phys_to_dma(dev, paddr);
}
/*
* arc_dma_unmap_page - unmap a buffer previously mapped through dma_map_page()
*
* After this call, reads by the CPU to the buffer are guaranteed to see
* whatever the device wrote there.
*
* Note: historically this routine was not implemented for ARC
*/
static void arc_dma_unmap_page(struct device *dev, dma_addr_t handle,
size_t size, enum dma_data_direction dir,
unsigned long attrs)
{
phys_addr_t paddr = plat_dma_to_phys(dev, handle);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
_dma_cache_sync(paddr, size, dir);
}
static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
@ -178,6 +209,18 @@ static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
return nents;
}
static void arc_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir,
unsigned long attrs)
{
struct scatterlist *s;
int i;
for_each_sg(sg, s, nents, i)
arc_dma_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir,
attrs);
}
static void arc_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
{
@ -223,7 +266,9 @@ const struct dma_map_ops arc_dma_ops = {
.free = arc_dma_free,
.mmap = arc_dma_mmap,
.map_page = arc_dma_map_page,
.unmap_page = arc_dma_unmap_page,
.map_sg = arc_dma_map_sg,
.unmap_sg = arc_dma_unmap_sg,
.sync_single_for_device = arc_dma_sync_single_for_device,
.sync_single_for_cpu = arc_dma_sync_single_for_cpu,
.sync_sg_for_cpu = arc_dma_sync_sg_for_cpu,