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authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>2014-06-18 12:15:38 +0300
committerVinod Koul <vinod.koul@intel.com>2014-07-15 22:14:30 +0530
commitdd8ecfcac66b4485416b2d1df0ec4798b198d7d6 (patch)
tree60a91f6fa94271e0a9ca229494793bd3407249f4 /drivers/dma/dw
parentcba15617c37cc6082c286c2a272202565f62e7bc (diff)
dmaengine: dw: don't perform DMA when dmaengine_submit is called
Accordingly to discussion [1] and followed up documentation the DMA controller driver shouldn't start any DMA operations when dmaengine_submit() is called. This patch fixes the workflow in dw_dmac driver to follow the documentation. [1] http://www.spinics.net/lists/arm-kernel/msg125987.html Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers/dma/dw')
-rw-r--r--drivers/dma/dw/core.c19
1 files changed, 7 insertions, 12 deletions
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 52815b905b7c..1af731b83b3f 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -684,17 +684,9 @@ static dma_cookie_t dwc_tx_submit(struct dma_async_tx_descriptor *tx)
* possible, perhaps even appending to those already submitted
* for DMA. But this is hard to do in a race-free manner.
*/
- if (list_empty(&dwc->active_list)) {
- dev_vdbg(chan2dev(tx->chan), "%s: started %u\n", __func__,
- desc->txd.cookie);
- list_add_tail(&desc->desc_node, &dwc->active_list);
- dwc_dostart(dwc, dwc_first_active(dwc));
- } else {
- dev_vdbg(chan2dev(tx->chan), "%s: queued %u\n", __func__,
- desc->txd.cookie);
- list_add_tail(&desc->desc_node, &dwc->queue);
- }
+ dev_vdbg(chan2dev(tx->chan), "%s: queued %u\n", __func__, desc->txd.cookie);
+ list_add_tail(&desc->desc_node, &dwc->queue);
spin_unlock_irqrestore(&dwc->lock, flags);
@@ -1099,9 +1091,12 @@ dwc_tx_status(struct dma_chan *chan,
static void dwc_issue_pending(struct dma_chan *chan)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+ unsigned long flags;
- if (!list_empty(&dwc->queue))
- dwc_scan_descriptors(to_dw_dma(chan->device), dwc);
+ spin_lock_irqsave(&dwc->lock, flags);
+ if (list_empty(&dwc->active_list))
+ dwc_dostart_first_queued(dwc);
+ spin_unlock_irqrestore(&dwc->lock, flags);
}
static int dwc_alloc_chan_resources(struct dma_chan *chan)