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Commit c9e0fc14 authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Sasha Levin
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dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer 



[ Upstream commit ee1cdcdae59563535485a5f56ee72c894ab7d7ad ]

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: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: default avatarMans Rullgard <mans@mansr.com>
Tested-by: default avatarMans Rullgard <mans@mansr.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
parent 0bacc2d3

drivers/dma/dw/core.c

+10 −5
Original line number Diff line number Diff line
@@ -148,7 +148,6 @@ 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;
@@ -580,6 +579,9 @@ 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);

}



/* ------------------------------------------------------------------------- */
@@ -610,11 +612,8 @@ 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);

}
@@ -1249,6 +1248,7 @@ 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)) {
@@ -1257,7 +1257,12 @@ 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;