[PATCH 3/3] at_hdmac: add FIFO configuration parameter to DMA DT binding

Ludovic Desroches ludovic.desroches at atmel.com
Mon Jun 3 03:39:07 EDT 2013


On Fri, May 31, 2013 at 04:11:40PM -0700, Olof Johansson wrote:
> On Fri, May 31, 2013 at 2:31 AM, Nicolas Ferre <nicolas.ferre at atmel.com> wrote:
> > On 31/05/2013 11:16, Ludovic Desroches :
> >>
> >> On Thu, May 30, 2013 at 06:39:36PM +0200, Jean-Christophe PLAGNIOL-VILLARD
> >> wrote:
> >>>
> >>> On 18:32 Thu 30 May     , Nicolas Ferre wrote:
> >>>>
> >>>> On 30/05/2013 18:08, ludovic.desroches at atmel.com :
> >>>>>
> >>>>> From: Ludovic Desroches <ludovic.desroches at atmel.com>
> >>>>>
> >>>>> For most devices the FIFO configuration is the same i.e. when half FIFO
> >>>>> size is
> >>>>> available/filled, a source/destination request is serviced. But USART
> >>>>> devices
> >>>>> have to do it when there is enough space/data available to perform a
> >>>>> single
> >>>>> AHB access so the ASAP configuration.
> >>>>>
> >>>>> Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> >>>>> Signed-off-by: Ludovic Desroches <ludovic.desroches at atmel.com>
> >>>>
> >>>>
> >>>> Clear and neat: thanks Ludo.
> >>>
> >>>
> >>> agreed
> >>>
> >>> can we apply this via AT91 as this depends on some cleanup I did on DT
> >>> and
> >>> could result on some nigthmware conflict
> >>>
> >>
> >> In fact, I am not sure it's the best solution. I have noticed that there
> >> is a
> >> conflict with a patch sent by Nicolas (dmaengine: at_hdmac: extend
> >> hardware
> >> handshaking interface identification) which is already in Vinod's tree but
> >> which is not present on Jean-Christophe's cleanup tree on which I based
> >> these
> >> patches.
> >>
> >> Moreover this patch doesn't use macros introduced by Nicolas' patch. I may
> >> update it and it should go through Vinod's tree with a dependence on patch
> >> 1/3.
> >>
> >> What's your point of view?
> >
> >
> > Indeed. Another option could be to push patches 1 and 3 in dmaengine's tree
> > and make the 2nd patch go through arm-soc with a dependency on slave-dma GIT
> > tree (it seems it is an usual patern).
> >
> > Arnd, Jean-Christophe, what do you think?
> 
> I'm not sure patch 1 needs to go through the dma-engine tree? Sure,
> it's a dma-related header file but it's only used to craft the device
> tree in patch 2, it doesn't affect the driver.
> 

Some macros are used into the at_hdmac driver. 

Ludovic

> (Arnd has comments on the patch that should be resolved though).
> 
> 
> -Olof



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