On Thu, 2011-08-25 at 18:45 +0200, Guennadi Liakhovetski wrote:
> To support multi-size buffers in the mx3_camera V4L2 driver we have to be
> able to stop DMA on a channel without releasing descriptors and completely
> halting the hardware. Use the DMA_PAUSE control to implement this mode.
>
> Signed-off-by: Guennadi Liakhovetski <[email protected]>
Acked-by Vinod Koul <[email protected]>
Do you want this to go thru slave-dma or media tree?
--
~Vinod
> ---
> drivers/dma/ipu/ipu_idmac.c | 65 +++++++++++++++++++++++++++---------------
> 1 files changed, 42 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/dma/ipu/ipu_idmac.c b/drivers/dma/ipu/ipu_idmac.c
> index c1a125e..42cdf1c 100644
> --- a/drivers/dma/ipu/ipu_idmac.c
> +++ b/drivers/dma/ipu/ipu_idmac.c
> @@ -1306,6 +1306,7 @@ static irqreturn_t idmac_interrupt(int irq, void
> *dev_id)
> ipu_submit_buffer(ichan, descnew, sgnew, ichan->active_buffer) < 0)
> {
> callback = descnew->txd.callback;
> callback_param = descnew->txd.callback_param;
> + list_del_init(&descnew->list);
> spin_unlock(&ichan->lock);
> if (callback)
> callback(callback_param);
> @@ -1427,39 +1428,58 @@ static int __idmac_control(struct dma_chan *chan,
> enum dma_ctrl_cmd cmd,
> {
> struct idmac_channel *ichan = to_idmac_chan(chan);
> struct idmac *idmac = to_idmac(chan->device);
> + struct ipu *ipu = to_ipu(idmac);
> + struct list_head *list, *tmp;
> unsigned long flags;
> int i;
>
> - /* Only supports DMA_TERMINATE_ALL */
> - if (cmd != DMA_TERMINATE_ALL)
> - return -ENXIO;
> + switch (cmd) {
> + case DMA_PAUSE:
> + spin_lock_irqsave(&ipu->lock, flags);
> + ipu_ic_disable_task(ipu, chan->chan_id);
>
> - ipu_disable_channel(idmac, ichan,
> - ichan->status >= IPU_CHANNEL_ENABLED);
> + /* Return all descriptors into "prepared" state */
> + list_for_each_safe(list, tmp, &ichan->queue)
> + list_del_init(list);
>
> - tasklet_disable(&to_ipu(idmac)->tasklet);
> + ichan->sg[0] = NULL;
> + ichan->sg[1] = NULL;
>
> - /* ichan->queue is modified in ISR, have to spinlock */
> - spin_lock_irqsave(&ichan->lock, flags);
> - list_splice_init(&ichan->queue, &ichan->free_list);
> + spin_unlock_irqrestore(&ipu->lock, flags);
>
> - if (ichan->desc)
> - for (i = 0; i < ichan->n_tx_desc; i++) {
> - struct idmac_tx_desc *desc = ichan->desc + i;
> - if (list_empty(&desc->list))
> - /* Descriptor was prepared, but not submitted */
> - list_add(&desc->list, &ichan->free_list);
> + ichan->status = IPU_CHANNEL_INITIALIZED;
> + break;
> + case DMA_TERMINATE_ALL:
> + ipu_disable_channel(idmac, ichan,
> + ichan->status >= IPU_CHANNEL_ENABLED);
>
> - async_tx_clear_ack(&desc->txd);
> - }
> + tasklet_disable(&ipu->tasklet);
>
> - ichan->sg[0] = NULL;
> - ichan->sg[1] = NULL;
> - spin_unlock_irqrestore(&ichan->lock, flags);
> + /* ichan->queue is modified in ISR, have to spinlock */
> + spin_lock_irqsave(&ichan->lock, flags);
> + list_splice_init(&ichan->queue, &ichan->free_list);
>
> - tasklet_enable(&to_ipu(idmac)->tasklet);
> + if (ichan->desc)
> + for (i = 0; i < ichan->n_tx_desc; i++) {
> + struct idmac_tx_desc *desc = ichan->desc + i;
> + if (list_empty(&desc->list))
> + /* Descriptor was prepared, but not
> submitted */
> + list_add(&desc->list,
> &ichan->free_list);
>
> - ichan->status = IPU_CHANNEL_INITIALIZED;
> + async_tx_clear_ack(&desc->txd);
> + }
> +
> + ichan->sg[0] = NULL;
> + ichan->sg[1] = NULL;
> + spin_unlock_irqrestore(&ichan->lock, flags);
> +
> + tasklet_enable(&ipu->tasklet);
> +
> + ichan->status = IPU_CHANNEL_INITIALIZED;
> + break;
> + default:
> + return -ENOSYS;
> + }
>
> return 0;
> }
> @@ -1662,7 +1682,6 @@ static void __exit ipu_idmac_exit(struct ipu *ipu)
> struct idmac_channel *ichan = ipu->channel + i;
>
> idmac_control(&ichan->dma_chan, DMA_TERMINATE_ALL, 0);
> - idmac_prep_slave_sg(&ichan->dma_chan, NULL, 0, DMA_NONE, 0);
> }
>
> dma_async_device_unregister(&idmac->dma);
--
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