Re: [PATCH v7 05/11] dmaengine: Introduce DMA-device device_caps callback

Vinod Koul
2020-07-14T16:08:38Z

On 13-07-20, 13:55, Dave Jiang wrote:
>
>
> On 7/10/2020 2:38 AM, Serge Semin wrote:
> > On Fri, Jul 10, 2020 at 11:45:03AM +0300, Andy Shevchenko wrote:
> > > On Fri, Jul 10, 2020 at 01:45:44AM +0300, Serge Semin wrote:
> > > > There are DMA devices (like ours version of Synopsys DW DMAC) which have
> > > > DMA capabilities non-uniformly redistributed between the device channels.
> > > > In order to provide a way of exposing the channel-specific parameters to
> > > > the DMA engine consumers, we introduce a new DMA-device callback. In case
> > > > if provided it gets called from the dma_get_slave_caps() method and is
> > > > able to override the generic DMA-device capabilities.
> > >
> >
> > > In light of recent developments consider not to add 'slave' and a such words to the kernel.
> >
> > As long as the 'slave' word is used in the name of the dma_slave_caps
> > structure and in the rest of the DMA-engine subsystem, it will be ambiguous
> > to use some else terminology. If renaming needs to be done, then it should be
> > done synchronously for the whole subsystem.
>
> What about just calling it dma_device_caps? Consider this is a useful
> function not only slave DMA will utilize this. I can see this being useful
> for some of my future code with idxd driver.

Some of the caps may make sense to generic dmaengine but few of them do
not :) While at it, am planning to make it dmaengine_periph_caps to
denote that these are dmaengine peripheral capabilities.

--
~Vinod