[PATCH v1 1/1] dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer

[PATCH v1 1/1] dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer

[Andy Shevchenko]

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>
Cc: Mans Rullgard <mans@mansr.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: <stable@vger.kernel.org>
---
 drivers/dma/dw/core.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index e893318..5ad0ec1 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -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);
 }
 
@@ -1261,6 +1260,7 @@ 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)) {
@@ -1269,7 +1269,12 @@ 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;
-- 
2.7.0

Re: [PATCH v1 1/1] dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer

[Måns Rullgård]

Andy Shevchenko <andriy.shevchenko@linux.intel.com> writes:

> 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>
> Cc: Mans Rullgard <mans@mansr.com>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: <stable@vger.kernel.org>
> ---
>  drivers/dma/dw/core.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)

Acked-by: Mans Rullgard <mans@mansr.com>
Tested-by: Mans Rullgard <mans@mansr.com>

> diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
> index e893318..5ad0ec1 100644
> --- a/drivers/dma/dw/core.c
> +++ b/drivers/dma/dw/core.c
> @@ -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);
>  }
>
> @@ -1261,6 +1260,7 @@ 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)) {
> @@ -1269,7 +1269,12 @@ 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;
> -- 
> 2.7.0
>

-- 
M�ns Rullg�rd

Re: [PATCH v1 1/1] dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer

[Viresh Kumar]

On 10-02-16, 15:59, Andy Shevchenko wrote:
> 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>
> Cc: Mans Rullgard <mans@mansr.com>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: <stable@vger.kernel.org>
> ---
>  drivers/dma/dw/core.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh

Re: [PATCH v1 1/1] dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer

[Vinod Koul]

On Wed, Feb 10, 2016 at 03:59:42PM +0200, Andy Shevchenko wrote:
> 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.

Applied, thanks

-- 
~Vinod