[ARM] pxa/dma: optimize irq handler loop
Reduce loop for dma irq handler callbacks to the minimum
required.
Since V1: included suggestion from Nicolas Pitre to improve
even further the loop.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
diff --git a/arch/arm/plat-pxa/dma.c b/arch/arm/plat-pxa/dma.c
index 897663d..56b51cf 100644
--- a/arch/arm/plat-pxa/dma.c
+++ b/arch/arm/plat-pxa/dma.c
@@ -94,20 +94,21 @@
static irqreturn_t dma_irq_handler(int irq, void *dev_id)
{
int i, dint = DINT;
+ struct dma_channel *channel;
- for (i = 0; i < num_dma_channels; i++) {
- if (dint & (1 << i)) {
- struct dma_channel *channel = &dma_channels[i];
- if (channel->name && channel->irq_handler) {
- channel->irq_handler(i, channel->data);
- } else {
- /*
- * IRQ for an unregistered DMA channel:
- * let's clear the interrupts and disable it.
- */
- printk (KERN_WARNING "spurious IRQ for DMA channel %d\n", i);
- DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
- }
+ while (dint) {
+ i = __ffs(dint);
+ dint &= (dint - 1);
+ channel = &dma_channels[i];
+ if (channel->name && channel->irq_handler) {
+ channel->irq_handler(i, channel->data);
+ } else {
+ /*
+ * IRQ for an unregistered DMA channel:
+ * let's clear the interrupts and disable it.
+ */
+ printk (KERN_WARNING "spurious IRQ for DMA channel %d\n", i);
+ DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
}
}
return IRQ_HANDLED;