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authorLinus Torvalds <torvalds@linux-foundation.org>2020-03-24 09:53:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-03-24 09:53:12 -0700
commitc6ac7188c1142c450eb601563ad69204bf1e9286 (patch)
tree29fc76466420afc8d5f50987c653157b2336df4f /Documentation
parent979e52ca0469fb38646bc51d26a0263a740c9f03 (diff)
parent018af9be3dd54e6f24f828966bdd873f4d63ad9b (diff)
Merge tag 'dmaengine-fix-5.6' of git://git.infradead.org/users/vkoul/slave-dma
Pull dmaengine fixes from Vinod Koul: "Late fixes in dmaengine for v5.6: - move .device_release missing log warning to debug - couple of maintainer entries for HiSilicon and IADX drivers - off-by-one fix for idxd driver - documentation warning fixes - TI k3 dma error handling fix" * tag 'dmaengine-fix-5.6' of git://git.infradead.org/users/vkoul/slave-dma: dmaengine: ti: k3-udma-glue: Fix an error handling path in 'k3_udma_glue_cfg_rx_flow()' MAINTAINERS: Add maintainer for HiSilicon DMA engine driver dmaengine: idxd: fix off by one on cdev dwq refcount MAINTAINERS: rectify the INTEL IADX DRIVER entry dmaengine: move .device_release missing log warning to debug level docs: dmaengine: provider.rst: get rid of some warnings
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/driver-api/dmaengine/provider.rst12
1 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/driver-api/dmaengine/provider.rst b/Documentation/driver-api/dmaengine/provider.rst
index 790a15089f1f..56e5833e8a07 100644
--- a/Documentation/driver-api/dmaengine/provider.rst
+++ b/Documentation/driver-api/dmaengine/provider.rst
@@ -266,11 +266,15 @@ to use.
attached (via the dmaengine_desc_attach_metadata() helper to the descriptor.
From the DMA driver the following is expected for this mode:
+
- DMA_MEM_TO_DEV / DEV_MEM_TO_MEM
+
The data from the provided metadata buffer should be prepared for the DMA
controller to be sent alongside of the payload data. Either by copying to a
hardware descriptor, or highly coupled packet.
+
- DMA_DEV_TO_MEM
+
On transfer completion the DMA driver must copy the metadata to the client
provided metadata buffer before notifying the client about the completion.
After the transfer completion, DMA drivers must not touch the metadata
@@ -284,10 +288,14 @@ to use.
and dmaengine_desc_set_metadata_len() is provided as helper functions.
From the DMA driver the following is expected for this mode:
- - get_metadata_ptr
+
+ - get_metadata_ptr()
+
Should return a pointer for the metadata buffer, the maximum size of the
metadata buffer and the currently used / valid (if any) bytes in the buffer.
- - set_metadata_len
+
+ - set_metadata_len()
+
It is called by the clients after it have placed the metadata to the buffer
to let the DMA driver know the number of valid bytes provided.