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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-07 04:20:54 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-07 04:20:54 +0200 |
commit | f72e24a1240b78f421649c4d88f5c24ab1c896a1 (patch) | |
tree | 90bed3bf33ae0abf5636dafcc3eda3cc354612b0 /Documentation | |
parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s39... (diff) | |
parent | ARM: dma-mapping: Remove traces of NOMMU code (diff) | |
download | linux-f72e24a1240b78f421649c4d88f5c24ab1c896a1.tar.xz linux-f72e24a1240b78f421649c4d88f5c24ab1c896a1.zip |
Merge tag 'dma-mapping-4.13' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping infrastructure from Christoph Hellwig:
"This is the first pull request for the new dma-mapping subsystem
In this new subsystem we'll try to properly maintain all the generic
code related to dma-mapping, and will further consolidate arch code
into common helpers.
This pull request contains:
- removal of the DMA_ERROR_CODE macro, replacing it with calls to
->mapping_error so that the dma_map_ops instances are more self
contained and can be shared across architectures (me)
- removal of the ->set_dma_mask method, which duplicates the
->dma_capable one in terms of functionality, but requires more
duplicate code.
- various updates for the coherent dma pool and related arm code
(Vladimir)
- various smaller cleanups (me)"
* tag 'dma-mapping-4.13' of git://git.infradead.org/users/hch/dma-mapping: (56 commits)
ARM: dma-mapping: Remove traces of NOMMU code
ARM: NOMMU: Set ARM_DMA_MEM_BUFFERABLE for M-class cpus
ARM: NOMMU: Introduce dma operations for noMMU
drivers: dma-mapping: allow dma_common_mmap() for NOMMU
drivers: dma-coherent: Introduce default DMA pool
drivers: dma-coherent: Account dma_pfn_offset when used with device tree
dma: Take into account dma_pfn_offset
dma-mapping: replace dmam_alloc_noncoherent with dmam_alloc_attrs
dma-mapping: remove dmam_free_noncoherent
crypto: qat - avoid an uninitialized variable warning
au1100fb: remove a bogus dma_free_nonconsistent call
MAINTAINERS: add entry for dma mapping helpers
powerpc: merge __dma_set_mask into dma_set_mask
dma-mapping: remove the set_dma_mask method
powerpc/cell: use the dma_supported method for ops switching
powerpc/cell: clean up fixed mapping dma_ops initialization
tile: remove dma_supported and mapping_error methods
xen-swiotlb: remove xen_swiotlb_set_dma_mask
arm: implement ->dma_supported instead of ->set_dma_mask
mips/loongson64: implement ->dma_supported instead of ->set_dma_mask
...
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/DMA-API-HOWTO.txt | 31 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt | 3 | ||||
-rw-r--r-- | Documentation/driver-model/devres.txt | 3 |
3 files changed, 9 insertions, 28 deletions
diff --git a/Documentation/DMA-API-HOWTO.txt b/Documentation/DMA-API-HOWTO.txt index 979228bc9035..4ed388356898 100644 --- a/Documentation/DMA-API-HOWTO.txt +++ b/Documentation/DMA-API-HOWTO.txt @@ -550,32 +550,11 @@ and to unmap it: dma_unmap_single(dev, dma_handle, size, direction); You should call dma_mapping_error() as dma_map_single() could fail and return -error. Not all DMA implementations support the dma_mapping_error() interface. -However, it is a good practice to call dma_mapping_error() interface, which -will invoke the generic mapping error check interface. Doing so will ensure -that the mapping code will work correctly on all DMA implementations without -any dependency on the specifics of the underlying implementation. Using the -returned address without checking for errors could result in failures ranging -from panics to silent data corruption. A couple of examples of incorrect ways -to check for errors that make assumptions about the underlying DMA -implementation are as follows and these are applicable to dma_map_page() as -well. - -Incorrect example 1: - dma_addr_t dma_handle; - - dma_handle = dma_map_single(dev, addr, size, direction); - if ((dma_handle & 0xffff != 0) || (dma_handle >= 0x1000000)) { - goto map_error; - } - -Incorrect example 2: - dma_addr_t dma_handle; - - dma_handle = dma_map_single(dev, addr, size, direction); - if (dma_handle == DMA_ERROR_CODE) { - goto map_error; - } +error. Doing so will ensure that the mapping code will work correctly on all +DMA implementations without any dependency on the specifics of the underlying +implementation. Using the returned address without checking for errors could +result in failures ranging from panics to silent data corruption. The same +applies to dma_map_page() as well. You should call dma_unmap_single() when the DMA activity is finished, e.g., from the interrupt which told you that the DMA transfer is done. diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt index 3da0ebdba8d9..16291f2a4688 100644 --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt @@ -68,6 +68,9 @@ Linux implementation note: - If a "linux,cma-default" property is present, then Linux will use the region for the default pool of the contiguous memory allocator. +- If a "linux,dma-default" property is present, then Linux will use the + region for the default pool of the consistent DMA allocator. + Device node references to reserved memory ----------------------------------------- Regions in the /reserved-memory node may be referenced by other device diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index 2d132fcea0f8..4231b45b2f8f 100644 --- a/Documentation/driver-model/devres.txt +++ b/Documentation/driver-model/devres.txt @@ -240,10 +240,9 @@ CLOCK DMA dmam_alloc_coherent() - dmam_alloc_noncoherent() + dmam_alloc_attrs() dmam_declare_coherent_memory() dmam_free_coherent() - dmam_free_noncoherent() dmam_pool_create() dmam_pool_destroy() |