[PATCH V4 04/14] DMA: PL330: Add DMA_CYCLIC capability

[Jassi Brar]

On Mon, Jul 25, 2011 at 6:58 AM, Boojin Kim <boojin.kim at samsung.com> 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 at samsung.com>
> ---
>  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.

> +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