[PATCH v6 04/15] DMA: PL330: Add DMA_CYCLIC capability

[Jassi Brar]

On Mon, Aug 22, 2011 at 5:33 PM, Boojin Kim <boojin.kim at samsung.com> wrote:
>>
>> > +static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic(
>> > +               struct dma_chan *chan, dma_addr_t dma_addr, size_t len,
>> > +               size_t period_len, enum dma_data_direction direction)
>> > +{
>> > +       struct dma_pl330_desc *desc;
>> > +       struct dma_pl330_chan *pch = to_pchan(chan);
>> > +       dma_addr_t dst;
>> > +       dma_addr_t src;
>> > +
>> > +       desc = pl330_get_desc(pch);
>> > +       if (!desc) {
>> > +               dev_err(pch->dmac->pif.dev, "%s:%d Unable to fetch
>> desc\n",
>> > +                       __func__, __LINE__);
>> > +               return NULL;
>> > +       }
>> > +
>> > +       switch (direction) {
>> > +       case DMA_TO_DEVICE:
>> > +               desc->rqcfg.src_inc = 1;
>> > +               desc->rqcfg.dst_inc = 0;
>> > +               src = dma_addr;
>> > +               dst = pch->fifo_addr;
>> > +               break;
>> > +       case DMA_FROM_DEVICE:
>> > +               desc->rqcfg.src_inc = 0;
>> > +               desc->rqcfg.dst_inc = 1;
>> > +               src = pch->fifo_addr;
>> > +               dst = dma_addr;
>> > +               break;
>> > +       default:
>> > +               dev_err(pch->dmac->pif.dev, "%s:%d Invalid dma
>> direction\n",
>> > +               __func__, __LINE__);
>> > +               return NULL;
>> > +       }
>> > +
>> > +       desc->rqcfg.brst_size = pch->burst_sz;
>> > +       desc->rqcfg.brst_len = 1;
>> > +
>> > +       if (!pch->cyclic)
>> > +               pch->cyclic = CYCLIC_PREP;
>> The need for check here seems suspicious.
>> Is it really needed? If not, please remove it.
> It's required because Cyclic operation is passed from CYCLIC_PREP to
> CYCLIC_TRIGGER.
I don't see why you need to differentiate between PREP and TRIGGER in
cyclic mode. I think, you should simply have 'bool cyclic' instead of enum.