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| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2014-06-18 12:15:38 +0300 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-10-13 15:41:40 +0200 |
| commit | a989feb087a51f54e00e36baace383cfffbf5fdb (patch) | |
| tree | 3bd398250126d62a1fcff6a4db791bd95bd0bd6c | |
| parent | e3c2bf19e5823dd742ad32ae9394143ae26effb1 (diff) | |
| download | lwn-a989feb087a51f54e00e36baace383cfffbf5fdb.tar.gz lwn-a989feb087a51f54e00e36baace383cfffbf5fdb.zip | |
dmaengine: dw: don't perform DMA when dmaengine_submit is called
commit dd8ecfcac66b4485416b2d1df0ec4798b198d7d6 upstream.
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>
Cc: "Petallo, MauriceX R" <mauricex.r.petallo@intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | drivers/dma/TODO | 1 | ||||
| -rw-r--r-- | drivers/dma/dw/core.c | 19 |
2 files changed, 7 insertions, 13 deletions
diff --git a/drivers/dma/TODO b/drivers/dma/TODO index 734ed0206cd5..b8045cd42ee1 100644 --- a/drivers/dma/TODO +++ b/drivers/dma/TODO @@ -7,7 +7,6 @@ TODO for slave dma - imx-dma - imx-sdma - mxs-dma.c - - dw_dmac - intel_mid_dma 4. Check other subsystems for dma drivers and merge/move to dmaengine 5. Remove dma_slave_config's dma direction. diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c index b240ba006401..a8884b8aaa9e 100644 --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -703,17 +703,9 @@ 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); @@ -1119,9 +1111,12 @@ 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) |