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dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer

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commit ee1cdcdae59563535485a5f56ee72c894ab7d7ad upstream.

The commit 2895b2cad6e7 ("dmaengine: dw: fix cyclic transfer callbacks")
re-enabled BLOCK interrupts with regard to make cyclic transfers work. However,
this change becomes a regression for non-cyclic transfers as interrupt counters
under stress test had been grown enormously (approximately per 4-5 bytes in the
UART loop back test).

Taking into consideration above enable BLOCK interrupts if and only if channel
is programmed to perform cyclic transfer.

Fixes: 2895b2cad6e7 ("dmaengine: dw: fix cyclic transfer callbacks")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mans Rullgard <mans@mansr.com>
Tested-by: Mans Rullgard <mans@mansr.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andy Shevchenko
2016-02-10 15:59:42 +02:00
committed by Greg Kroah-Hartman
parent f4fa3d6f9e
commit 556dfd8dae
1 changed files with 10 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/dma/dw/core.c
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@@ -156,7 +156,6 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
/* Enable interrupts */
channel_set_bit(dw, MASK.XFER, dwc->mask);
channel_set_bit(dw, MASK.BLOCK, dwc->mask);
channel_set_bit(dw, MASK.ERROR, dwc->mask);
dwc->initialized = true;
@@ -588,6 +587,9 @@ static void dwc_handle_cyclic(struct dw_dma *dw, struct dw_dma_chan *dwc,
spin_unlock_irqrestore(&dwc->lock, flags);
}
/* Re-enable interrupts */
channel_set_bit(dw, MASK.BLOCK, dwc->mask);
}
/* ------------------------------------------------------------------------- */
@@ -618,11 +620,8 @@ static void dw_dma_tasklet(unsigned long data)
dwc_scan_descriptors(dw, dwc);
}
/*
* Re-enable interrupts.
*/
/* Re-enable interrupts */
channel_set_bit(dw, MASK.XFER, dw->all_chan_mask);
channel_set_bit(dw, MASK.BLOCK, dw->all_chan_mask);
channel_set_bit(dw, MASK.ERROR, dw->all_chan_mask);
}
@@ -1256,6 +1255,7 @@ 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(chan->device);
unsigned long flags;
if (!test_bit(DW_DMA_IS_CYCLIC, &dwc->flags)) {
@@ -1264,7 +1264,12 @@ int dw_dma_cyclic_start(struct dma_chan *chan)
}
spin_lock_irqsave(&dwc->lock, flags);
/* Enable interrupts to perform cyclic transfer */
channel_set_bit(dw, MASK.BLOCK, dwc->mask);
dwc_dostart(dwc, dwc->cdesc->desc[0]);
spin_unlock_irqrestore(&dwc->lock, flags);
return 0;