[PATCH v3 8/9] dmaengine: dw: return immediately from IRQ when DMA isn't in use

Andy Shevchenko
2015-12-04T21:49:24Z

There is no need to bother the hardware when all channels are idle. We have not
to get any interrupts.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/dma/dw/core.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 7067b6d..8b20930 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -622,12 +622,17 @@ static void dw_dma_tasklet(unsigned long data)
static irqreturn_t dw_dma_interrupt(int irq, void *dev_id)
{
struct dw_dma *dw = dev_id;
- u32 status = dma_readl(dw, STATUS_INT);
+ u32 status;

+ /* Check if we have any interrupt from the DMAC which is not in use */
+ if (!dw->in_use)
+ return IRQ_NONE;
+
+ status = dma_readl(dw, STATUS_INT);
dev_vdbg(dw->dma.dev, "%s: status=0x%x\n", __func__, status);

/* Check if we have any interrupt from the DMAC */
- if (!status || !dw->in_use)
+ if (!status)
return IRQ_NONE;

/*
--
2.6.2