diff options
| author |   Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2014-06-18 12:15:38 +0300 |
|---|---|---|
| committer |   Vinod Koul <vinod.koul@intel.com> | 2014-07-15 22:14:30 +0530 |
| commit | dd8ecfcac66b4485416b2d1df0ec4798b198d7d6 (patch) | |
| tree | 60a91f6fa94271e0a9ca229494793bd3407249f4 /drivers/dma/dw | |
| parent | dmaengine: dw: add debug message to dwc_dostart_first_queued (diff) | |
| download | linux-dev-dd8ecfcac66b4485416b2d1df0ec4798b198d7d6.tar.xz linux-dev-dd8ecfcac66b4485416b2d1df0ec4798b198d7d6.zip | |
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.c | 19 |
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) |