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authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>2014-06-18 12:15:38 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-10-05 14:52:24 -0700
commit5257a3de5b34b7f89f71026fb553a0b84736ff66 (patch)
tree0df0950b432911e66fc2ce258e749945892ad9b0
parent97a4115f3d3b7add0983dcc78dfd99ff19007bdd (diff)
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/dma/TODO1
-rw-r--r--drivers/dma/dw/core.c19
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 d585787aabc0..b0972b3869c7 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -680,17 +680,9 @@ 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);
@@ -1095,9 +1087,12 @@ 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)