Subject: [PATCH 7/8] dmaengine/dw_dmac: Unmap all memory buffers after completion of slave transfers

From: [email-masked] (Viresh Kumar)
Date: Tue, 17 Jan 2012 14:37:10 +0530

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