Re: + mmc-add-dma-support-to-tmio_mmc-driver-when-used-on-superh.patch

Re: + mmc-add-dma-support-to-tmio_mmc-driver-when-used-on-superh.patch

[Guennadi Liakhovetski]

(re-adding CC)

On Thu, 13 May 2010, Ian Molton wrote:

> Might be worth exposing for now, whilst the feature is new. but yes,
> automatic select yes on all the platforms you are comfortable with.
> 
> Im not sure if it should be per MFD or per platform. I tend to think
> the latter, given that its slave DMA and thus I could have the same
> MFD in platforms with different CPUs (eg. e740 and e800) where a CPU
> bug might upset one but not the other.

So far I went for the least effort - not exposed, selected by MFDs. If we 
ever have a need to change this, e.g., make it user-selectable or per 
platform, we can always do so later. For now all SuperH / SH-Mobile 
platforms I tested can use this driver with DMA. Expect updated patches 
shortly.

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/

Re: + mmc-add-dma-support-to-tmio_mmc-driver-when-used-on-superh.patch

[Guennadi Liakhovetski]

On Thu, 13 May 2010, Guennadi Liakhovetski wrote:

> On Thu, 13 May 2010, Ian Molton wrote:
> 
> > Might be worth exposing for now, whilst the feature is new. but yes,
> > automatic select yes on all the platforms you are comfortable with.
> > 
> > Im not sure if it should be per MFD or per platform. I tend to think
> > the latter, given that its slave DMA and thus I could have the same
> > MFD in platforms with different CPUs (eg. e740 and e800) where a CPU
> > bug might upset one but not the other.
> 
> So far I went for the least effort - not exposed, selected by MFDs. If we 
> ever have a need to change this, e.g., make it user-selectable or per 
> platform, we can always do so later. For now all SuperH / SH-Mobile 
> platforms I tested can use this driver with DMA. Expect updated patches 
> shortly.

One more thing I forgot to mention - even if your MFD enables DMA, it 
still can further decide when (on which platforms) to enable and when to 
disable DMA by providing or not providing DMA slave configuration to 
tmio_mmc.

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/

Re: + mmc-add-dma-support-to-tmio_mmc-driver-when-used-on-superh.patch

[Ian Molton]

Sounds good to me, and you're right - the MFD level is good for this
config option.

-- 
Ian Molton
Linux, Automotive, and other hacking:
http://www.mnementh.co.uk/



On 13 May 2010 15:18, Guennadi Liakhovetski <g.liakhovetski@gmx.de> wrote:
> On Thu, 13 May 2010, Guennadi Liakhovetski wrote:
>
>> On Thu, 13 May 2010, Ian Molton wrote:
>>
>> > Might be worth exposing for now, whilst the feature is new. but yes,
>> > automatic select yes on all the platforms you are comfortable with.
>> >
>> > Im not sure if it should be per MFD or per platform. I tend to think
>> > the latter, given that its slave DMA and thus I could have the same
>> > MFD in platforms with different CPUs (eg. e740 and e800) where a CPU
>> > bug might upset one but not the other.
>>
>> So far I went for the least effort - not exposed, selected by MFDs. If we
>> ever have a need to change this, e.g., make it user-selectable or per
>> platform, we can always do so later. For now all SuperH / SH-Mobile
>> platforms I tested can use this driver with DMA. Expect updated patches
>> shortly.
>
> One more thing I forgot to mention - even if your MFD enables DMA, it
> still can further decide when (on which platforms) to enable and when to
> disable DMA by providing or not providing DMA slave configuration to
> tmio_mmc.
>
> Thanks
> Guennadi
> ---
> Guennadi Liakhovetski, Ph.D.
> Freelance Open-Source Software Developer
> http://www.open-technology.de/
>