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authorLinus Torvalds <torvalds@linux-foundation.org>2020-03-05 12:19:34 -0600
committerLinus Torvalds <torvalds@linux-foundation.org>2020-03-05 12:19:34 -0600
commit6fd145da21af43dd069463d83d89aefcc6675eba (patch)
treea1ccfd7cb370a49d1ef030ccd434bb11eaace456 /Documentation
parent776e49e8ddb5169e6477fd33a396e9c7b2eb7400 (diff)
parent25962e1a7f1d522f1b57ead2f266fab570042a70 (diff)
downloadlinux-6fd145da21af43dd069463d83d89aefcc6675eba.tar.bz2
Merge tag 'dmaengine-fix-5.6-rc5' of git://git.infradead.org/users/vkoul/slave-dma
Pull dmaengine fixes from Vinod Koul: "A bunch of driver fixes: - Doc updates to clean warnings for dmaengine - Fixes for newly added Intel idxd driver - More fixes for newly added TI k3-udma driver - Fixes for IMX and Tegra drivers" * tag 'dmaengine-fix-5.6-rc5' of git://git.infradead.org/users/vkoul/slave-dma: dmaengine: imx-sdma: Fix the event id check to include RX event for UART6 dmaengine: tegra-apb: Prevent race conditions of tasklet vs free list dmaengine: tegra-apb: Fix use-after-free dmaengine: imx-sdma: fix context cache dmaengine: idxd: wq size configuration needs to check global max size dmaengine: idxd: sysfs input of wq incorrect wq type should return error dmaengine: coh901318: Fix a double lock bug in dma_tc_handle() dmaengine: idxd: correct reserved token calculation dmaengine: ti: k3-udma: Fix terminated transfer handling dmaengine: ti: k3-udma: Use the channel direction in pause/resume functions dmaengine: ti: k3-udma: Use the TR counter helper for slave_sg and cyclic dmaengine: ti: k3-udma: Move the TR counter calculation to helper function dmaengine: ti: k3-udma: Workaround for RX teardown with stale data in peer dmaengine: ti: k3-udma: Use ktime/usleep_range based TX completion check dmaengine: idxd: Fix error handling in idxd_wq_cdev_dev_setup() dmaengine: doc: fix warnings/issues of client.rst dmaengine: idxd: fix runaway module ref count on device driver bind
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/driver-api/dmaengine/client.rst14
1 files changed, 10 insertions, 4 deletions
diff --git a/Documentation/driver-api/dmaengine/client.rst b/Documentation/driver-api/dmaengine/client.rst
index e5953e7e4bf4..2104830a99ae 100644
--- a/Documentation/driver-api/dmaengine/client.rst
+++ b/Documentation/driver-api/dmaengine/client.rst
@@ -151,8 +151,8 @@ The details of these operations are:
Note that callbacks will always be invoked from the DMA
engines tasklet, never from interrupt context.
-Optional: per descriptor metadata
----------------------------------
+ **Optional: per descriptor metadata**
+
DMAengine provides two ways for metadata support.
DESC_METADATA_CLIENT
@@ -199,12 +199,15 @@ Optional: per descriptor metadata
DESC_METADATA_CLIENT
- DMA_MEM_TO_DEV / DEV_MEM_TO_MEM:
+
1. prepare the descriptor (dmaengine_prep_*)
construct the metadata in the client's buffer
2. use dmaengine_desc_attach_metadata() to attach the buffer to the
descriptor
3. submit the transfer
+
- DMA_DEV_TO_MEM:
+
1. prepare the descriptor (dmaengine_prep_*)
2. use dmaengine_desc_attach_metadata() to attach the buffer to the
descriptor
@@ -215,6 +218,7 @@ Optional: per descriptor metadata
DESC_METADATA_ENGINE
- DMA_MEM_TO_DEV / DEV_MEM_TO_MEM:
+
1. prepare the descriptor (dmaengine_prep_*)
2. use dmaengine_desc_get_metadata_ptr() to get the pointer to the
engine's metadata area
@@ -222,7 +226,9 @@ Optional: per descriptor metadata
4. use dmaengine_desc_set_metadata_len() to tell the DMA engine the
amount of data the client has placed into the metadata buffer
5. submit the transfer
+
- DMA_DEV_TO_MEM:
+
1. prepare the descriptor (dmaengine_prep_*)
2. submit the transfer
3. on transfer completion, use dmaengine_desc_get_metadata_ptr() to get
@@ -278,8 +284,8 @@ Optional: per descriptor metadata
void dma_async_issue_pending(struct dma_chan *chan);
-Further APIs:
--------------
+Further APIs
+------------
1. Terminate APIs