media: rcar-vin: Add check for completed capture before completing buffer

Before reading which slot was captured to by examining the module status
(VnMS) register, make sure something was captured at all by examining
the interrupt status register (VnINTS).

Failing this a buffer maybe completed before it was captured too.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c b/drivers/media/platform/rcar-vin/rcar-dma.c
index 79bb9081853f..8136bc75e7c4 100644
--- a/drivers/media/platform/rcar-vin/rcar-dma.c
+++ b/drivers/media/platform/rcar-vin/rcar-dma.c
@@ -111,6 +111,9 @@
 #define VNIE_FIE		(1 << 4)
 #define VNIE_EFE		(1 << 1)
 
+/* Video n Interrupt Status Register bits */
+#define VNINTS_FIS		(1 << 4)
+
 /* Video n Data Mode Register bits */
 #define VNDMR_A8BIT(n)		(((n) & 0xff) << 24)
 #define VNDMR_A8BIT_MASK	(0xff << 24)
@@ -1005,6 +1008,10 @@ static irqreturn_t rvin_irq(int irq, void *data)
 	rvin_ack_interrupt(vin);
 	handled = 1;
 
+	/* Nothing to do if nothing was captured. */
+	if (!(int_status & VNINTS_FIS))
+		goto done;
+
 	/* Nothing to do if capture status is 'STOPPED' */
 	if (vin->state == STOPPED) {
 		vin_dbg(vin, "IRQ while state stopped\n");