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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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Lars-Peter Clausen 2014-01-11 20:08:38 +01:00 committed by Vinod Koul
parent ba07d812f5
commit 04abf5daf7
1 changed files with 20 additions and 4 deletions
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24
drivers/dma/pl330.c
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@ -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);