Re: [PATCH 7/8] dmaengine/dw_dmac: Unmap all memory buffers aftercompletion of slave transfers
From: Russell King - ARM Linux
Date: Wed Jan 18 2012 - 04:36:27 EST
On Tue, Jan 17, 2012 at 02:37:10PM +0530, Viresh Kumar wrote:
> 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);
Take a look at that. "If *NOT* slave, unmap the buffers". That is in
keeping with what I've been saying. Slave transfers *do* *not* get
automatic buffer unmapping.
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