Re: [PATCH v12 05/11] edma: config: Enable config options for EDMA

From: Joel A Fernandes
Date: Mon Jun 24 2013 - 16:10:23 EST


On Mon, Jun 24, 2013 at 6:23 AM, Sekhar Nori <nsekhar@xxxxxx> wrote:
> On 6/22/2013 3:23 AM, Joel A Fernandes wrote:
>> Hi Arnd,
>>
>> On Fri, Jun 21, 2013 at 1:44 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
>>> On Friday 21 June 2013, Joel A Fernandes wrote:
>>>> I think we are talking about different things, I agree the 'select
>>>> DMADEVICES' can be dropped but lets please keep the default y option
>>>> (not adding new select statements, just saying that if someone select
>>>> DMADEVICES in menuconfig and if they're ARCH_OMAP=1 , then default to
>>>> EDMA). This will simply allow people to have a default. Thanks.
>>>
>>> Yes, that's ok.
>>
>> Ok, thanks. I will follow up with a patch in my next submissions that builds it.
>>
>> Perhaps a:
>> default y if 'ARCH_OMAP2PLUS'
>>
>> and leave the existing as it is...
>> default n if 'ARCH_DAVINCI || ARCH_OMAP1 || ARCH_OMAP2'
>>
>> would make most sense to me. Basically EDMA is seen on current and all
>> new OMAP2PLUS.
>
> OMAP2PLUS devices like OMAP3/4 do not have EDMA so this is not really true.

Sure. Right now though, and from what I've seen, all future SoCs are
supporting EDMA.

>>
>>>
>>> config TI_EDMA
>>> tristate "TI EDMA support"
>>> default m if 'ARCH_DAVINCI || ARCH_OMAP1 || ARCH_OMAP2
>>> select DMA_ENGINE
>>> select DMA_VIRTUAL_CHANNELS
>>
>>
>>
>> MMC depends on EDMA specially on AM33xx there's no PIO mode AFAIK. The
>> 'm' option will require some initramfs to load the module when needing
>> to MMC boot, I suggest lets leave it as y.
>
> But there is no reason why it cannot work with PIO, right? Sounds like
> the right fix is in driver.

I am not sure about this. I agree no reason it cannot do PIO. I will check.
But even if it did, loading EDMA as a module will require omap_hsmmc to switch
to DMA mode which I am sure the driver doesn't support today.

Thanks,
Joel
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