dmaengine: axi-dmac: Return IRQ_NONE if no IRQs are pending

Return IRQ_NONE in the interrupt handler when it is called but no IRQs are
pending. This allows the system to recover in case of an interrupt storm
e.g. due to a wrong interrupt configuration setup.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/dma-axi-dmac.c

@@ -270,6 +270,9 @@ static irqreturn_t axi_dmac_interrupt_handler(int irq, void *devid)
 	unsigned int pending;
 
 	pending = axi_dmac_read(dmac, AXI_DMAC_REG_IRQ_PENDING);
+	if (!pending)
+		return IRQ_NONE;
+
 	axi_dmac_write(dmac, AXI_DMAC_REG_IRQ_PENDING, pending);
 
 	spin_lock(&dmac->chan.vchan.lock);