From: Jacopo Mondi <jacopo.mondi+renesas@ideasonboard.com>

The start/stop streaming routines do not need to lock the whole function
body against possible concurrent accesses to the CRU buffers or hardware
registers.

The stop function starts by disabling interrupts, and only this portion
needs to be protected not to race against a possible IRQ.

Once interrupts are disabled, nothing in the video device driver can race
and once the peripheral has been disabled we can release all pending
buffers.

Signed-off-by: Jacopo Mondi <jacopo.mondi+renesas@ideasonboard.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Tested-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Reviewed-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
---
 drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
index 75928b0f48be..96c71f1357f8 100644
--- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
+++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
@@ -340,23 +340,19 @@ bool rzg2l_fifo_empty(struct rzg2l_cru_dev *cru)
 void rzg2l_cru_stop_image_processing(struct rzg2l_cru_dev *cru)
 {
 	unsigned int retries = 0;
-	unsigned long flags;
 	u32 icnms;
 
-	spin_lock_irqsave(&cru->qlock, flags);
-
-	/* Disable and clear the interrupt */
-	cru->info->disable_interrupts(cru);
+	scoped_guard(spinlock_irq, &cru->qlock) {
+		/* Disable and clear the interrupt */
+		cru->info->disable_interrupts(cru);
+	}
 
 	/* Stop the operation of image conversion */
 	rzg2l_cru_write(cru, ICnEN, 0);
 
 	/* Wait for streaming to stop */
-	while ((rzg2l_cru_read(cru, ICnMS) & ICnMS_IA) && retries++ < RZG2L_RETRIES) {
-		spin_unlock_irqrestore(&cru->qlock, flags);
+	while ((rzg2l_cru_read(cru, ICnMS) & ICnMS_IA) && retries++ < RZG2L_RETRIES)
 		msleep(RZG2L_TIMEOUT_MS);
-		spin_lock_irqsave(&cru->qlock, flags);
-	}
 
 	icnms = rzg2l_cru_read(cru, ICnMS) & ICnMS_IA;
 	if (icnms)
@@ -400,8 +396,6 @@ void rzg2l_cru_stop_image_processing(struct rzg2l_cru_dev *cru)
 
 	/* Resets the image processing module */
 	rzg2l_cru_write(cru, CRUnRST, 0);
-
-	spin_unlock_irqrestore(&cru->qlock, flags);
 }
 
 static int rzg2l_cru_get_virtual_channel(struct rzg2l_cru_dev *cru)
@@ -469,8 +463,6 @@ int rzg2l_cru_start_image_processing(struct rzg2l_cru_dev *cru)
 	csi_vc = ret;
 	cru->svc_channel = csi_vc;
 
-	guard(spinlock_irqsave)(&cru->qlock);
-
 	/* Select a video input */
 	rzg2l_cru_write(cru, CRUnCTRL, CRUnCTRL_VINSEL(0));
 

-- 
2.53.0