path: root/Documentation/DMA-API.txt
diff options
authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-10 18:54:48 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-10 18:54:48 (GMT)
commitb7a7d1c1ec688104fdc922568c26395a756f616d (patch)
tree8059a401de91431615737b088f3da20d4567683e /Documentation/DMA-API.txt
parent065b6c4c913d3986c2118acb7e7fb364ce4fb625 (diff)
parent9eb9e96e97b3381e94cba81d93f4a390c26ca6cb (diff)
Merge tag 'dma-mapping-5.1' of git://git.infradead.org/users/hch/dma-mapping
Pull DMA mapping updates from Christoph Hellwig: - add debugfs support for dumping dma-debug information (Corentin Labbe) - Kconfig cleanups (Andy Shevchenko and me) - debugfs cleanups (Greg Kroah-Hartman) - improve dma_map_resource and use it in the media code - arch_setup_dma_ops / arch_teardown_dma_ops cleanups - various small cleanups and improvements for the per-device coherent allocator - make the DMA mask an upper bound and don't fail "too large" dma mask in the remaning two architectures - this will allow big driver cleanups in the following merge windows * tag 'dma-mapping-5.1' of git://git.infradead.org/users/hch/dma-mapping: (21 commits) Documentation/DMA-API-HOWTO: update dma_mask sections sparc64/pci_sun4v: allow large DMA masks sparc64/iommu: allow large DMA masks sparc64: refactor the ali DMA quirk ccio: allow large DMA masks dma-mapping: remove the DMA_MEMORY_EXCLUSIVE flag dma-mapping: remove dma_mark_declared_memory_occupied dma-mapping: move CONFIG_DMA_CMA to kernel/dma/Kconfig dma-mapping: improve selection of dma_declare_coherent availability dma-mapping: remove an incorrect __iommem annotation of: select OF_RESERVED_MEM automatically device.h: dma_mem is only needed for HAVE_GENERIC_DMA_COHERENT mfd/sm501: depend on HAS_DMA dma-mapping: add a kconfig symbol for arch_teardown_dma_ops availability dma-mapping: add a kconfig symbol for arch_setup_dma_ops availability dma-mapping: move debug configuration options to kernel/dma dma-debug: add dumping facility via debugfs dma: debug: no need to check return value of debugfs_create functions videobuf2: replace a layering violation with dma_map_resource dma-mapping: don't BUG when calling dma_map_resource on RAM ...
Diffstat (limited to 'Documentation/DMA-API.txt')
1 files changed, 4 insertions, 25 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 607c1e7..5866436 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -566,8 +566,7 @@ boundaries when doing this.
dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
- dma_addr_t device_addr, size_t size, int
- flags)
+ dma_addr_t device_addr, size_t size);
Declare region of memory to be handed out by dma_alloc_coherent() when
it's asked for coherent memory for this device.
@@ -581,12 +580,6 @@ dma_addr_t in dma_alloc_coherent()).
size is the size of the area (must be multiples of PAGE_SIZE).
-flags can be ORed together and are:
-- DMA_MEMORY_EXCLUSIVE - only allocate memory from the declared regions.
- Do not allow dma_alloc_coherent() to fall back to system memory when
- it's out of memory in the declared region.
As a simplification for the platforms, only *one* such region of
memory may be declared per device.
@@ -605,23 +598,6 @@ unconditionally having removed all the required structures. It is the
driver's job to ensure that no parts of this memory region are
currently in use.
- void *
- dma_mark_declared_memory_occupied(struct device *dev,
- dma_addr_t device_addr, size_t size)
-This is used to occupy specific regions of the declared space
-(dma_alloc_coherent() will hand out the first free region it finds).
-device_addr is the *device* address of the region requested.
-size is the size (and should be a page-sized multiple).
-The return value will be either a pointer to the processor virtual
-address of the memory, or an error (via PTR_ERR()) if any part of the
-region is occupied.
Part III - Debug drivers use of the DMA-API
@@ -696,6 +672,9 @@ dma-api/disabled This read-only file contains the character 'Y'
happen when it runs out of memory or if it was
disabled at boot time
+dma-api/dump This read-only file contains current DMA
+ mappings.
dma-api/error_count This file is read-only and shows the total
numbers of errors found.