dmaengine: xilinx: xdma: Fix synchronization issue

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The current xdma_synchronize method does not properly wait for the last
transfer to be done. Due to limitations of the XMDA engine, it is not
possible to stop a transfer in the middle of a descriptor. Said
otherwise, if a stop is requested at the end of descriptor "N" and the OS
is fast enough, the DMA controller will effectively stop immediately.
However, if the OS is slightly too slow to request the stop and the DMA
engine starts descriptor "N+1", the N+1 transfer will be performed until
its end. This means that after a terminate_all, the last descriptor must
remain valid and the synchronization must wait for this last descriptor to
be terminated.

Fixes: 855c2e1d18 ("dmaengine: xilinx: xdma: Rework xdma_terminate_all()")
Fixes: f5c392d106 ("dmaengine: xilinx: xdma: Add terminate_all/synchronize callbacks")
Cc: stable@vger.kernel.org
Suggested-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Link: https://lore.kernel.org/r/20240327-digigram-xdma-fixes-v1-2-45f4a52c0283@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

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This commit is contained in:

Louis Chauvet 2024-03-27 10:58:49 +01:00 • committed by Vinod Koul

parent 5b9706bfc0

commit 6a40fb8245

2 changed files with 21 additions and 8 deletions

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3

drivers/dma/xilinx/xdma-regs.h

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26

drivers/dma/xilinx/xdma.c

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