xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

dma-mapping: add a new dma_alloc_noncoherent API

Browse Source 
Add a new API to allocate and free memory that is guaranteed to be
addressable by a device, but which potentially is not cache coherent
for DMA.

To transfer ownership to and from the device, the existing streaming
DMA API calls dma_sync_single_for_device and dma_sync_single_for_cpu
must be used.

For now the new calls are implemented on top of dma_alloc_attrs just
like the old-noncoherent API, but once all drivers are switched to
the new API it will be replaced with a better working implementation
that is available on all architectures.

Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Christoph Hellwig
2020-09-01 13:31:30 +02:00
parent 91af2dd255
commit 0d71675f87
2 changed files with 48 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
include/linux/dma-mapping.h
View File

@@ -384,6 +384,18 @@ static inline unsigned long dma_get_merge_boundary(struct device *dev)
}
#endif /* CONFIG_HAS_DMA */
static inline void *dma_alloc_noncoherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
{
return dma_alloc_attrs(dev, size, dma_handle, gfp,
DMA_ATTR_NON_CONSISTENT);
}
static inline void dma_free_noncoherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle, enum dma_data_direction dir)
{
dma_free_attrs(dev, size, vaddr, dma_handle, DMA_ATTR_NON_CONSISTENT);
}
static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{