Jassi Brar Wrote:
> Sent: Monday, July 25, 2011 8:24 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 04/14] DMA: PL330: Add DMA_CYCLIC capability
>
> On Mon, Jul 25, 2011 at 6:58 AM, Boojin Kim <boojin.kim@xxxxxxxxxxx>
> wrote:
> > This patch adds DMA_CYCLIC capability that is used for audio driver.
> > DMA driver with DMA_CYCLIC capability reuses the dma requests that
> > were submitted through tx_submit().
> >
> > Signed-off-by: Boojin Kim <boojin.kim@xxxxxxxxxxx>
> > ---
> > drivers/dma/pl330.c | 111
> +++++++++++++++++++++++++++++++++++++++++++++++++++
> > 1 files changed, 111 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> > index 880f010..121c75a 100644
> > --- a/drivers/dma/pl330.c
> > +++ b/drivers/dma/pl330.c
> > @@ -69,6 +69,11 @@ struct dma_pl330_chan {
> > * NULL if the channel is available to be acquired.
> > */
> > void *pl330_chid;
> > +
> > + /* taks for cyclic capability */
> > + struct tasklet_struct *cyclic_task;
> > +
> > + bool cyclic;
> > };
> We already have a tasklet_struct member here.
> This 'cyclic' flag can indicate if we are doing cyclic or serial
> transfers. So, this cyclic_task seems unnecessary.
I will change cyclic operation base on your comment.
Cyclic_task will be removed.
>
> > +static void pl330_tasklet_cyclic(unsigned long data)
> > +{
> > + struct dma_pl330_chan *pch = (struct dma_pl330_chan *)data;
> > + struct dma_pl330_desc *desc, *_dt;
> > + unsigned long flags;
> > + LIST_HEAD(list);
> > +
> > + spin_lock_irqsave(&pch->lock, flags);
> > +
> > + /* Pick up ripe tomatoes */
> > + list_for_each_entry_safe(desc, _dt, &pch->work_list, node)
> > + if (desc->status == DONE) {
> > + dma_async_tx_callback callback;
> > +
> > + list_move_tail(&desc->node, &pch->work_list);
> > + pch->completed = desc->txd.cookie;
> > +
> > + desc->status = PREP;
> > +
> > + /* Try to submit a req imm.
> > + next to the last completed cookie */
> > + fill_queue(pch);
> > +
> > + /* Make sure the PL330 Channel thread is active
> */
> > + pl330_chan_ctrl(pch->pl330_chid,
> PL330_OP_START);
> > +
> > + callback = desc->txd.callback;
> > + if (callback)
> > + callback(desc->txd.callback_param);
> > +
> > + }
> > +
> > + spin_unlock_irqrestore(&pch->lock, flags);
> > +}
> Please merge this with pl330_tasklet and use 'cyclic' flag to
> differentiate.
>
> > @@ -227,6 +267,9 @@ static void dma_pl330_rqcb(void *token, enum
> pl330_op_err err)
> >
> > spin_unlock_irqrestore(&pch->lock, flags);
> >
> > + if (pch->cyclic_task)
> > + tasklet_schedule(pch->cyclic_task);
> > + else
> > tasklet_schedule(&pch->task);
> A tab here please, and check for 'cyclic' flag.
>
>
> > @@ -316,6 +359,15 @@ static void pl330_free_chan_resources(struct
> dma_chan *chan)
> > pl330_release_channel(pch->pl330_chid);
> > pch->pl330_chid = NULL;
> >
> > + if (pch->cyclic) {
> > + pch->cyclic = false;
> > + list_splice_tail_init(&pch->work_list, &pch->dmac-
> >desc_pool);
> > + if (pch->cyclic_task) {
> > + tasklet_kill(pch->cyclic_task);
> > + pch->cyclic_task = NULL;
> > + }
> > + }
> > +
> > spin_unlock_irqrestore(&pch->lock, flags);
> > }
> To be explicit, please initialize 'cyclic' flag to false in
> pl330_alloc_chan_resources
I will address your comment.
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