Re: [PATCH] serial: sh-sci: don't filter on DMA device, use onlychannel ID

[Koul, Vinod]

On Wed, 2011-09-07 at 22:01 +0200, Guennadi Liakhovetski wrote:
> On Thu, 8 Sep 2011, Koul, Vinod wrote:
> You're seriously suggesting to export and use an additional shdma private 
> function, bypassing the dmaengine API?... That really doesn't sound like a 
> good idea to me, sorry. How about using .device_control(DMA_SLAVE_CONFIG) 
> from the filter function directly to verify channel suitability?
Yes see stedma40, coh90138 drivers
.device_control is not right place as channel is already allocated.

You are basically moving filter fn from all clients to dmac driver.

> 
> > I cant agree to the whole point of filtering in alloc
> > 
> > One channel is allocated, we should _not_ do any further filtering
> 
> Sorry, I do not understand this argumentation. Filtering and resource 
> allocation are parts of the channel-acquisition process, either of them 
> can fail, in which case the channel remains free for future requests.
DMA drivers set caps for each channel
Client requests a channel and dmaengine matches channel based on caps
and filer function is called so that additional filtering can take
place.
And .alloc_chan_resources is supposed to allocate the channel resource
and not do anything else.

--
~Vinod

èº{.nÇ+‰·Ÿ®‰­†+%ŠËlzwm…ébëæìr¸›zX§»®w¥Š{ayºÊÚë,j­¢f£¢·hš‹àz¹®w¥¢¸¢·¦j:+v‰¨ŠwèjØm¶Ÿÿ¾«‘êçzZ+ƒùšŽŠÝj"ú!¶iO•æ¬z·švØ^¶m§ÿðÃnÆàþY&—