media: rkisp1: Fix IRQ disable race issue

[ Upstream commit 870565f0 ]

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@ideasonboard.com



Tested-by: Adam Ford <aford173@gmail.com>  #imx8mp-beacon
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>