[PATCH V4 06/14] ARM: SAMSUNG: Add common DMA operations

[Jassi Brar]

On Tue, Jul 26, 2011 at 3:05 PM, Boojin Kim <boojin.kim at samsung.com> wrote:
> Jassi Brar Wrote:
>> Sent: Monday, July 25, 2011 8:52 PM
>> To: Boojin Kim
>> Cc: linux-arm-kernel at lists.infradead.org; linux-samsung-
>> soc at vger.kernel.org; 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 at samsung.com>
>> 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,