Re: [PATCH 5/7 v2] dma: sh: use an integer slave ID to improve APIcompatibility

From: Vinod Koul
Date: Mon Jul 16 2012 - 04:28:34 EST

On Mon, 2012-07-16 at 09:13 +0200, Guennadi Liakhovetski wrote:
> > > They tell the driver how the channel has to be configured to
> support this
> > > specific client. They are values of two specific registers. In
> fact, CHCR
> > > means exactly that - CHannel Control Register.
> > what exactly does the channel control register do in shdma? Should
> shdma
> > driver deduce this value rather than client giving it?
> > Same question for mid_rid?
> See, e.g.,
> arch/arm/mach-shmobile/setup-sh7372.c::sh7372_dmae_slaves[].
> Platforms are supplying these values with shdma driver platform data,
> together with slave IDs. Them when slaves request channels and supply
> their slave IDs, the driver searches the above array, looking for the
> matching slave ID, then it uses the rest of the information in those
> structs to configure the channel for this client. Again, this is
> nothing
> new, this is how the driver has been functioning since a long time,
> this
> driver is not modifying anything there. Any changes to this
> procedure,
> like providing all thig information from clients themselves instead
> of
> keeping it with DMACs, requires these patches to be committed first.
That wasn't my question.

I want to know what does ccr and mid_rid mean to dmac here?


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