Re: [PATCH v7 01/10] ARM: davinci: move private EDMA API to arm/common

[Sergei Shtylyov]

Hello.

On 02-02-2013 0:56, Felipe Balbi wrote:

> > > good point, do you wanna send some patches ?

> >     I have already sent them countless times and even stuck CPPI 4.1 support (in
> > arch/arm/common/cppi41.c) in Russell's patch system. TI requested to remove the
> > patch. :-(

> sticking into arch/arm/common/ wasn't a nice move.

   Like with EDMA we have nothing else to do with CPPI 4.1 being shared by 
DaVinci-like and OMAP-like SOCs. Thank TI for creatring this mess. And 
actually even that is not a good place since I think I know of a MIPS SoC 
having CPPI 4.1 as well, just out of tree.

> But then again, so
> wasn't asking for the patch to be removed :-s

   Unfortunately, Russell has done it -- all that was discuseed without me in 
the loop even. :-/

> > > I guess to make the MUSB side simpler we would need musb-dma-engine glue
> > > to map dmaengine to the private MUSB API. Then we would have some
> > > starting point to also move inventra (and anybody else) to dmaengine
> > > API.

> >     Why? Inventra is a dedicated device's private DMA controller, why make
> > universal DMA driver for it?

> because it doesn't make sense to support multiple DMA APIs. We can check
> from MUSB's registers if it was configured with Inventra DMA support and
> based on that we can register MUSB's own DMA Engine to dmaengine API.

    I still disagree. IMO drivers/dma/ is for standalone DMA engines. Else we 
could stick every bus mastering device's DMA engines there. CPPI 4.1 is in 
design standlone DMA engine, despite all in-tree implementations having it as 
subblock of MUSB and serving only MUSB.

WBR, Sergei

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