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dmaengine: stm32-dma: Rework starting transfer management

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This patch reworks the way to manage transfer starting.
Now, starting DMA is only allowed when the channel is not busy.
Then, stm32_dma_start_transfer is declared as void.
At least, after each transfer completion, we start the next transfer if a
new descriptor as been queued in the issued list during an ongoing
transfer.

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Reviewed-by: Ludovic BARRE <ludovic.barre@st.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
M'boumba Cedric Madianga 2016-12-13 14:40:47 +01:00 committed by Vinod Koul
parent 16545502d7
commit 8d1b76f031
1 changed files with 9 additions and 11 deletions
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20
drivers/dma/stm32-dma.c
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@ -421,7 +421,7 @@ static void stm32_dma_dump_reg(struct stm32_dma_chan *chan)
dev_dbg(chan2dev(chan), "SFCR: 0x%08x\n", sfcr);
}
static int stm32_dma_start_transfer(struct stm32_dma_chan *chan)
static void stm32_dma_start_transfer(struct stm32_dma_chan *chan)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
struct virt_dma_desc *vdesc;
@ -432,12 +432,12 @@ static int stm32_dma_start_transfer(struct stm32_dma_chan *chan)
ret = stm32_dma_disable_chan(chan);
if (ret < 0)
return ret;
return;
if (!chan->desc) {
vdesc = vchan_next_desc(&chan->vchan);
if (!vdesc)
return -EPERM;
return;
chan->desc = to_stm32_dma_desc(vdesc);
chan->next_sg = 0;
@ -471,7 +471,7 @@ static int stm32_dma_start_transfer(struct stm32_dma_chan *chan)
chan->busy = true;
return 0;
dev_dbg(chan2dev(chan), "vchan %p: started\n", &chan->vchan);
}
static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan)
@ -552,15 +552,13 @@ static void stm32_dma_issue_pending(struct dma_chan *c)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
unsigned long flags;
int ret;
spin_lock_irqsave(&chan->vchan.lock, flags);
if (!chan->busy) {
if (vchan_issue_pending(&chan->vchan) && !chan->desc) {
ret = stm32_dma_start_transfer(chan);
if ((!ret) && (chan->desc->cyclic))
stm32_dma_configure_next_sg(chan);
}
if (vchan_issue_pending(&chan->vchan) && !chan->desc && !chan->busy) {
dev_dbg(chan2dev(chan), "vchan %p: issued\n", &chan->vchan);
stm32_dma_start_transfer(chan);
if (chan->desc->cyclic)
stm32_dma_configure_next_sg(chan);
}
spin_unlock_irqrestore(&chan->vchan.lock, flags);
}