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Merge tag 'dma-mapping-5.8-2' of git://git.infradead.org/users/hch/dma-mapping

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Pull dma-mapping helpers from Christoph Hellwig:
 "These were in a separate stable branch so that various media and drm
  trees could pull the in for bug fixes, but looking at linux-next that
  hasn't actually happened yet. Still sending the APIs to you in the
  hope that these bug fixes get picked up for 5.8 in one way or another.

  Summary:

   - add DMA mapping helpers for struct sg_table (Marek Szyprowski)"

* tag 'dma-mapping-5.8-2' of git://git.infradead.org/users/hch/dma-mapping:
  iommu: add generic helper for mapping sgtable objects
  scatterlist: add generic wrappers for iterating over sgtable objects
  dma-mapping: add generic helpers for mapping sgtable objects
This commit is contained in:
Linus Torvalds
2020-06-06 11:55:53 -07:00
parent 1ee18de929 48530d9fab
commit 6f2dc3d335
3 changed files with 143 additions and 3 deletions
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80
include/linux/dma-mapping.h
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@@ -609,6 +609,86 @@ static inline void dma_sync_single_range_for_device(struct device *dev,
return dma_sync_single_for_device(dev, addr + offset, size, dir);
}
/**
* dma_map_sgtable - Map the given buffer for DMA
* @dev: The device for which to perform the DMA operation
* @sgt: The sg_table object describing the buffer
* @dir: DMA direction
* @attrs: Optional DMA attributes for the map operation
*
* Maps a buffer described by a scatterlist stored in the given sg_table
* object for the @dir DMA operation by the @dev device. After success the
* ownership for the buffer is transferred to the DMA domain. One has to
* call dma_sync_sgtable_for_cpu() or dma_unmap_sgtable() to move the
* ownership of the buffer back to the CPU domain before touching the
* buffer by the CPU.
*
* Returns 0 on success or -EINVAL on error during mapping the buffer.
*/
static inline int dma_map_sgtable(struct device *dev, struct sg_table *sgt,
enum dma_data_direction dir, unsigned long attrs)
{
int nents;
nents = dma_map_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs);
if (nents <= 0)
return -EINVAL;
sgt->nents = nents;
return 0;
}
/**
* dma_unmap_sgtable - Unmap the given buffer for DMA
* @dev: The device for which to perform the DMA operation
* @sgt: The sg_table object describing the buffer
* @dir: DMA direction
* @attrs: Optional DMA attributes for the unmap operation
*
* Unmaps a buffer described by a scatterlist stored in the given sg_table
* object for the @dir DMA operation by the @dev device. After this function
* the ownership of the buffer is transferred back to the CPU domain.
*/
static inline void dma_unmap_sgtable(struct device *dev, struct sg_table *sgt,
enum dma_data_direction dir, unsigned long attrs)
{
dma_unmap_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs);
}
/**
* dma_sync_sgtable_for_cpu - Synchronize the given buffer for CPU access
* @dev: The device for which to perform the DMA operation
* @sgt: The sg_table object describing the buffer
* @dir: DMA direction
*
* Performs the needed cache synchronization and moves the ownership of the
* buffer back to the CPU domain, so it is safe to perform any access to it
* by the CPU. Before doing any further DMA operations, one has to transfer
* the ownership of the buffer back to the DMA domain by calling the
* dma_sync_sgtable_for_device().
*/
static inline void dma_sync_sgtable_for_cpu(struct device *dev,
struct sg_table *sgt, enum dma_data_direction dir)
{
dma_sync_sg_for_cpu(dev, sgt->sgl, sgt->orig_nents, dir);
}
/**
* dma_sync_sgtable_for_device - Synchronize the given buffer for DMA
* @dev: The device for which to perform the DMA operation
* @sgt: The sg_table object describing the buffer
* @dir: DMA direction
*
* Performs the needed cache synchronization and moves the ownership of the
* buffer back to the DMA domain, so it is safe to perform the DMA operation.
* Once finished, one has to call dma_sync_sgtable_for_cpu() or
* dma_unmap_sgtable().
*/
static inline void dma_sync_sgtable_for_device(struct device *dev,
struct sg_table *sgt, enum dma_data_direction dir)
{
dma_sync_sg_for_device(dev, sgt->sgl, sgt->orig_nents, dir);
}
#define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, 0)
#define dma_unmap_single(d, a, s, r) dma_unmap_single_attrs(d, a, s, r, 0)
#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, 0)