ARM: OMAP: Add DMA IRQ sanity checks

Add DMA IRQ sanity checks

Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 18 insertions, 7 deletions

diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index f3f84fbf8b87..2d86b106ff3e 100644
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -925,10 +925,17 @@ static int omap2_dma_handle_ch(int ch)
 {
         u32 status = OMAP_DMA_CSR_REG(ch);
 
-        if (!status)
+        if (!status) {
+                if (printk_ratelimit())
+                        printk(KERN_WARNING "Spurious DMA IRQ for lch %d\n", ch);
                 return 0;
-        if (unlikely(dma_chan[ch].dev_id == -1))
+        }
+        if (unlikely(dma_chan[ch].dev_id == -1)) {
+                if (printk_ratelimit())
+                        printk(KERN_WARNING "IRQ %04x for non-allocated DMA"
+                                        "channel %d\n", status, ch);
                 return 0;
+        }
         if (unlikely(status & OMAP_DMA_DROP_IRQ))
                 printk(KERN_INFO
                        "DMA synchronization event drop occurred with device "
@@ -959,11 +966,15 @@ static irqreturn_t omap2_dma_irq_handler(int irq, void *dev_id)
         int i;
 
         val = omap_readl(OMAP_DMA4_IRQSTATUS_L0);
-
-        for (i = 1; i <= OMAP_LOGICAL_DMA_CH_COUNT; i++) {
-                int active = val & (1 << (i - 1));
-                if (active)
-                        omap2_dma_handle_ch(i - 1);
+        if (val == 0) {
+                if (printk_ratelimit())
+                        printk(KERN_WARNING "Spurious DMA IRQ\n");
+                return IRQ_HANDLED;
+        }
+        for (i = 0; i < OMAP_LOGICAL_DMA_CH_COUNT && val != 0; i++) {
+                if (val & 1)
+                        omap2_dma_handle_ch(i);
+                val >>= 1;
         }
 
         return IRQ_HANDLED;