This is a note to let you know that I've just added the patch titled
media: rkisp1: Fix IRQ disable race issue
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
media-rkisp1-fix-irq-disable-race-issue.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit af950f48fbbd17ce5e256e98bbb86b488bd65a1f
Author: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
Date: Thu Dec 7 08:57:48 2023 +0100
media: rkisp1: Fix IRQ disable race issue
[ Upstream commit 870565f063a58576e8a4529f122cac4325c6b395 ]
In rkisp1_isp_stop() and rkisp1_csi_disable() the driver masks the
interrupts and then apparently assumes that the interrupt handler won't
be running, and proceeds in the stop procedure. This is not the case, as
the interrupt handler can already be running, which would lead to the
ISP being disabled while the interrupt handler handling a captured
frame.
This brings up two issues: 1) the ISP could be powered off while the
interrupt handler is still running and accessing registers, leading to
board lockup, and 2) the interrupt handler code and the code that
disables the streaming might do things that conflict.
It is not clear to me if 2) causes a real issue, but 1) can be seen with
a suitable delay (or printk in my case) in the interrupt handler,
leading to board lockup.
Link: https://lore.kernel.org/r/20231207-rkisp-irq-fix-v3-4-358a2c871a3c@xxxxxxxxxxxxxxxx
Tested-by: Adam Ford <aford173@xxxxxxxxx> #imx8mp-beacon
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c
index fdff3d0da4e5..0a67eb96402c 100644
--- a/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c
+++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c
@@ -141,8 +141,20 @@ static void rkisp1_csi_disable(struct rkisp1_csi *csi)
struct rkisp1_device *rkisp1 = csi->rkisp1;
u32 val;
- /* Mask and clear interrupts. */
+ /* Mask MIPI interrupts. */
rkisp1_write(rkisp1, RKISP1_CIF_MIPI_IMSC, 0);
+
+ /* Flush posted writes */
+ rkisp1_read(rkisp1, RKISP1_CIF_MIPI_IMSC);
+
+ /*
+ * Wait until the IRQ handler has ended. The IRQ handler may get called
+ * even after this, but it will return immediately as the MIPI
+ * interrupts have been masked.
+ */
+ synchronize_irq(rkisp1->irqs[RKISP1_IRQ_MIPI]);
+
+ /* Clear MIPI interrupt status */
rkisp1_write(rkisp1, RKISP1_CIF_MIPI_ICR, ~0);
val = rkisp1_read(rkisp1, RKISP1_CIF_MIPI_CTRL);
diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
index 07fbb77ce234..2239fb6c7d39 100644
--- a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
+++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
@@ -281,11 +281,25 @@ static void rkisp1_isp_stop(struct rkisp1_isp *isp)
* ISP(mi) stop in mi frame end -> Stop ISP(mipi) ->
* Stop ISP(isp) ->wait for ISP isp off
*/
- /* stop and clear MI and ISP interrupts */
- rkisp1_write(rkisp1, RKISP1_CIF_ISP_IMSC, 0);
- rkisp1_write(rkisp1, RKISP1_CIF_ISP_ICR, ~0);
+ /* Mask MI and ISP interrupts */
+ rkisp1_write(rkisp1, RKISP1_CIF_ISP_IMSC, 0);
rkisp1_write(rkisp1, RKISP1_CIF_MI_IMSC, 0);
+
+ /* Flush posted writes */
+ rkisp1_read(rkisp1, RKISP1_CIF_MI_IMSC);
+
+ /*
+ * Wait until the IRQ handler has ended. The IRQ handler may get called
+ * even after this, but it will return immediately as the MI and ISP
+ * interrupts have been masked.
+ */
+ synchronize_irq(rkisp1->irqs[RKISP1_IRQ_ISP]);
+ if (rkisp1->irqs[RKISP1_IRQ_ISP] != rkisp1->irqs[RKISP1_IRQ_MI])
+ synchronize_irq(rkisp1->irqs[RKISP1_IRQ_MI]);
+
+ /* Clear MI and ISP interrupt status */
+ rkisp1_write(rkisp1, RKISP1_CIF_ISP_ICR, ~0);
rkisp1_write(rkisp1, RKISP1_CIF_MI_ICR, ~0);
/* stop ISP */
