dmaengine: axi-dmac: Discover length alignment requirement

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Starting with version 4.1.a the AXI-DMAC is capable of reporting the
required length alignment.

The LSBs that are required to be set for alignment will always read back as
set from the transfer length register. It is not possible to clear them by
writing a 0. This means the driver can discover the length alignment
requirement by writing 0 to that register and reading back the value.

Since the DMA will support length alignment requirements that are different
from the address alignment requirement track both of them independently.

For older versions of the peripheral assume that the length alignment
requirement is equal to the address alignment requirement.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

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Lars-Peter Clausen 2019-05-27 09:55:17 +03:00 • committed by Vinod Koul

parent d27ac2e02b

commit a5b20600a6

1 changed files with 18 additions and 5 deletions

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drivers/dma/dma-axi-dmac.c

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