On Wed, Jul 27, 2011 at 10:47 AM, Boojin Kim <boojin.kim@xxxxxxxxxxx> wrote:
> Jassi Brar wrote:
>> Sent: Wednesday, July 27, 2011 10:34 AM
>> To: Boojin Kim
>> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-samsung-
>> soc@xxxxxxxxxxxxxxx; Vinod Koul; Dan Williams; Kukjin Kim; Grant
>> Likely; Mark Brown
>> Subject: Re: [PATCH V4 06/14] ARM: SAMSUNG: Add common DMA operations
>>
>> On Tue, Jul 26, 2011 at 3:05 PM, Boojin Kim <boojin.kim@xxxxxxxxxxx>
>> wrote:
>> > Jassi Brar Wrote:
>> >> Sent: Monday, July 25, 2011 8:52 PM
>> >> To: Boojin Kim
>> >> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-samsung-
>> >> soc@xxxxxxxxxxxxxxx; Vinod Koul; Dan Williams; Kukjin Kim; Grant
>> >> Likely; Mark Brown
>> >> Subject: Re: [PATCH V4 06/14] ARM: SAMSUNG: Add common DMA
>> operations
>> >>
>> >> On Mon, Jul 25, 2011 at 6:58 AM, Boojin Kim
>> <boojin.kim@xxxxxxxxxxx>
>> >> wrote:
>> >>
>> >> > +
>> >> > +static bool pl330_filter(struct dma_chan *chan, void *param)
>> >> > +{
>> >> > + struct dma_pl330_peri *peri = (struct dma_pl330_peri
>> *)chan-
>> >> >private;
>> >> > + unsigned dma_ch = (unsigned)param;
>> >> > +
>> >> > + if (peri->peri_id != dma_ch)
>> >> > + return false;
>> >> > +
>> >> > + return true;
>> >> > +}
>> >> This is what I meant... if we keep chan_id for paltform assigned
>> IDs,
>> >> these filter functions could simply become
>> >>
>> >> static bool pl330_filter(struct dma_chan *chan, void *param)
>> >> {
>> >> return chan->chan_id == param
>> >> }
>> >>
>> >> And ideally in the long run, we could just drop the filter callback
>> >> and add expected channel ID to the request_channel call.
>> > The chan_id is set by dmaengine. So, We don't use it to hold the
>> user specific
>> > Id.
>> Not for long.
>> See https://lkml.org/lkml/2011/7/26/245
>>
>>
>> >> > +
>> >> > +static inline int s3c_dma_trigger(unsigned ch)
>> >> > +{
>> >> > + return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_START);
>> >> > +}
>> >> > +
>> >> > +static inline int s3c_dma_started(unsigned ch)
>> >> > +{
>> >> > + return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_STARTED);
>> >> > +}
>> >> > +
>> >> > +static inline int s3c_dma_flush(unsigned ch)
>> >> > +{
>> >> > + return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_FLUSH);
>> >> > +}
>> >> > +
>> >> > +static inline int s3c_dma_stop(unsigned ch)
>> >> > +{
>> >> > + return s3c2410_dma_ctrl(ch, S3C2410_DMAOP_STOP);
>> >> > +}
>> >> > +
>> >> > +static struct samsung_dma_ops s3c_dma_ops = {
>> >> > + .request = s3c_dma_request,
>> >> > + .release = s3c_dma_release,
>> >> > + .prepare = s3c_dma_prepare,
>> >> > + .trigger = s3c_dma_trigger,
>> >> > + .started = s3c_dma_started,
>> >> > + .flush = s3c_dma_flush,
>> >> > + .stop = s3c_dma_stop,
>> >>
>> >> These last 4 should be gnereallized into one callback with OP
>> argument.
>> > I don't have any idea about it. Can you explain it in more detail?
>>
>> static int s3c_dma_control(unsigned ch, enum s3c2410_chan_op/*or
>> similar*/ op)
>> {
>> return s3c2410_dma_ctrl(ch, op);
>> }
>>
>> static struct samsung_dma_ops s3c_dma_ops = {
>> .request = s3c_dma_request,
>> .release = s3c_dma_release,
>> .prepare = s3c_dma_prepare,
>> .control = s3c_dma_control,
> 'Struct samsung_dma_ops' is used for both 'S3C-DMA-OPS' for 's3c dma' and
> 'DMA-OPS' for 'dmaengine'.
> If I modify "Struct samsung_dma_ops" as your guide, It gives un-expectable
> effect to DMA-OPS.
> Actually, We don't want the client with 'DMA-OPS' uses 'enum s3c2410_chan_op'
> operation anymore.
" enum s3c2410_chan_op /* or similar */ " <<<< note 'or similar'
Defining a callback for each value of the argument doesn't make sense.
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