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SubjectRe: [PATCH 7/8] dmaengine/dw_dmac: Unmap all memory buffers after completion of slave transfers
On 1/17/2012 2:22 PM, Linus Walleij wrote:
> Basically the driver using the dmaengine shall map/unmap buffers
> used for slave transfers, not the driver.
>
> I usually map them before setting up a transfer and unmaps them
> when egtting the callback from the DMA engine that the transfer is
> complete.
>

You implemented similar stuff in amba-pl08x :) .

if (!plchan->slave)
pl08x_unmap_buffers(txd);
> Why do you want to do this?

This is because people can pass in flags which are
DMA_COMPL_SKIP_SRC_UNMAP, etc.

If they are not passed, then DMA driver must do it for them.

Sorry if i am understanding the DMA logic incorrectly.

--
viresh


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