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Subject[PATCH 3.13.y-ckt 072/136] dmaengine: dw: fix cyclic transfer setup
Date
3.13.11-ckt34 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Mans Rullgard <mans@mansr.com>

commit df3bb8a0e619d501cd13334c3e0586edcdcbc716 upstream.

Commit 61e183f83069 ("dmaengine/dw_dmac: Reconfigure interrupt and
chan_cfg register on resume") moved some channel initialisation to
a new function which must be called before starting a transfer.

This updates dw_dma_cyclic_start() to use dwc_dostart() like the other
modes, thus ensuring dwc_initialize() gets called and removing some code
duplication.

Fixes: 61e183f83069 ("dmaengine/dw_dmac: Reconfigure interrupt and chan_cfg register on resume")
Signed-off-by: Mans Rullgard <mans@mansr.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
[ kamal: backport to 3.19-stable: context ]
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
drivers/dma/dw/core.c | 22 +---------------------
1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index b24ee31..529948e 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -1209,7 +1209,6 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
int dw_dma_cyclic_start(struct dma_chan *chan)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
- struct dw_dma *dw = to_dw_dma(dwc->chan.device);
unsigned long flags;

if (!test_bit(DW_DMA_IS_CYCLIC, &dwc->flags)) {
@@ -1218,26 +1217,7 @@ int dw_dma_cyclic_start(struct dma_chan *chan)
}

spin_lock_irqsave(&dwc->lock, flags);
-
- /* Assert channel is idle */
- if (dma_readl(dw, CH_EN) & dwc->mask) {
- dev_err(chan2dev(&dwc->chan),
- "BUG: Attempted to start non-idle channel\n");
- dwc_dump_chan_regs(dwc);
- spin_unlock_irqrestore(&dwc->lock, flags);
- return -EBUSY;
- }
-
- dma_writel(dw, CLEAR.ERROR, dwc->mask);
- dma_writel(dw, CLEAR.XFER, dwc->mask);
-
- /* Setup DMAC channel registers */
- channel_writel(dwc, LLP, dwc->cdesc->desc[0]->txd.phys);
- channel_writel(dwc, CTL_LO, DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN);
- channel_writel(dwc, CTL_HI, 0);
-
- channel_set_bit(dw, CH_EN, dwc->mask);
-
+ dwc_dostart(dwc, dwc->cdesc->desc[0]);
spin_unlock_irqrestore(&dwc->lock, flags);

return 0;
--
1.9.1
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