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Commit 04abf5da authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Vinod Koul
Browse files

dma: pl330: Differentiate between submitted and issued descriptors 



The pl330 dmaengine driver currently does not differentiate between submitted
and issued descriptors. It won't start transferring a newly submitted
descriptor until issue_pending() is called, but only if it is idle. If it is
active and a new descriptor is submitted before it goes idle it will happily
start the newly submitted descriptor once all earlier submitted descriptors have
been completed. This is not a 100% correct with regards to the dmaengine
interface semantics. A descriptor is not supposed to be started until the next
issue_pending() call after the descriptor has been submitted. This patch adds a
second per channel list that keeps track of the submitted descriptors. Once
issue_pending() is called the submitted descriptors are moved to the working
list and only descriptors on the working list are started.

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent ba07d812

drivers/dma/pl330.c

+20 −4
Original line number Diff line number Diff line
@@ -543,7 +543,9 @@ struct dma_pl330_chan { 
	/* DMA-Engine Channel */

	struct dma_chan chan;



	/* List of to be xfered descriptors */

	/* List of submitted descriptors */

	struct list_head submitted_list;

	/* List of issued descriptors */

	struct list_head work_list;

	/* List of completed descriptors */

	struct list_head completed_list;
@@ -2388,6 +2390,11 @@ static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned 
		pl330_chan_ctrl(pch->pl330_chid, PL330_OP_FLUSH);



		/* Mark all desc done */

		list_for_each_entry(desc, &pch->submitted_list, node) {

			desc->status = FREE;

			dma_cookie_complete(&desc->txd);

		}



		list_for_each_entry(desc, &pch->work_list , node) {

			desc->status = FREE;

			dma_cookie_complete(&desc->txd);
@@ -2398,6 +2405,7 @@ static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned 
			dma_cookie_complete(&desc->txd);

		}



		list_splice_tail_init(&pch->submitted_list, &pdmac->desc_pool);

		list_splice_tail_init(&pch->work_list, &pdmac->desc_pool);

		list_splice_tail_init(&pch->completed_list, &pdmac->desc_pool);

		spin_unlock_irqrestore(&pch->lock, flags);
@@ -2456,7 +2464,14 @@ pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie, 


static void pl330_issue_pending(struct dma_chan *chan)

{

	pl330_tasklet((unsigned long) to_pchan(chan));

	struct dma_pl330_chan *pch = to_pchan(chan);

	unsigned long flags;



	spin_lock_irqsave(&pch->lock, flags);

	list_splice_tail_init(&pch->submitted_list, &pch->work_list);

	spin_unlock_irqrestore(&pch->lock, flags);



	pl330_tasklet((unsigned long)pch);

}



/*
@@ -2483,11 +2498,11 @@ static dma_cookie_t pl330_tx_submit(struct dma_async_tx_descriptor *tx) 


		dma_cookie_assign(&desc->txd);



		list_move_tail(&desc->node, &pch->work_list);

		list_move_tail(&desc->node, &pch->submitted_list);

	}



	cookie = dma_cookie_assign(&last->txd);

	list_add_tail(&last->node, &pch->work_list);

	list_add_tail(&last->node, &pch->submitted_list);

	spin_unlock_irqrestore(&pch->lock, flags);



	return cookie;
@@ -2979,6 +2994,7 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id) 
		else

			pch->chan.private = adev->dev.of_node;



		INIT_LIST_HEAD(&pch->submitted_list);

		INIT_LIST_HEAD(&pch->work_list);

		INIT_LIST_HEAD(&pch->completed_list);

		spin_lock_init(&pch->lock);