dmaengine: set_dma40: ignore spurious interrupts

Some DMA channels may be used by other cores in the SoC.  This patch
modifies the dma interrupt handler to ignore interrupts from unknown
channels.

Cc: Rabin Vincent <rabin.vincent@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>

1 files changed, 12 insertions, 3 deletions

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 2ecefb7113b9..a97bbd3a4a47 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -1677,13 +1677,22 @@ static irqreturn_t d40_handle_interrupt(int irq, void *data)
                 row = chan / BITS_PER_LONG;
                 idx = chan & (BITS_PER_LONG - 1);
 
-                /* ACK interrupt */
-                writel(1 << idx, base->virtbase + il[row].clr);
-
                 if (il[row].offset == D40_PHY_CHAN)
                         d40c = base->lookup_phy_chans[idx];
                 else
                         d40c = base->lookup_log_chans[il[row].offset + idx];
+
+                if (!d40c) {
+                        /*
+                         * No error because this can happen if something else
+                         * in the system is using the channel.
+                         */
+                        continue;
+                }
+
+                /* ACK interrupt */
+                writel(1 << idx, base->virtbase + il[row].clr);
+
                 spin_lock(&d40c->lock);
 
                 if (!il[row].is_error)