[PATCH 03/13] media: stm32: dcmipp: bytecap: protect CMIER register access
From: Alain Volmat <alain.volmat@foss.st.com>
Date: 2026-02-02 13:58:11
Also in:
linux-arm-kernel, linux-media, lkml
Subsystem:
media drivers for stm32 - dcmi / dcmipp, media input infrastructure (v4l/dvb), the rest · Maintainers:
Hugues Fruchet, Alain Volmat, Mauro Carvalho Chehab, Linus Torvalds
CMIER register is common between all pipes and thus needs to be protected from concurrent access. The struct v4l2_device structure, unique to the whole driver embeds a spin_lock which can also be used by the driver itself as explained in its description. Rely on this spin_lock to protect from concurrent access to the CMIER register. Signed-off-by: Alain Volmat <alain.volmat@foss.st.com> --- drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c
index 1b7edf0d2938..0b1d1fbda5d6 100644
--- a/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c
+++ b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c@@ -436,7 +436,9 @@ static int dcmipp_bytecap_start_streaming(struct vb2_queue *vq, dcmipp_start_capture(vcap, vcap->next); /* Enable interruptions */ + spin_lock(&vcap->vdev.v4l2_dev->lock); reg_set(vcap, DCMIPP_CMIER, DCMIPP_CMIER_P0ALL); + spin_unlock(&vcap->vdev.v4l2_dev->lock); vcap->state = DCMIPP_RUNNING;
@@ -492,7 +494,9 @@ static void dcmipp_bytecap_stop_streaming(struct vb2_queue *vq) media_pipeline_stop(vcap->vdev.entity.pads); /* Disable interruptions */ + spin_lock(&vcap->vdev.v4l2_dev->lock); reg_clear(vcap, DCMIPP_CMIER, DCMIPP_CMIER_P0ALL); + spin_unlock(&vcap->vdev.v4l2_dev->lock); /* Stop capture */ reg_clear(vcap, DCMIPP_P0FCTCR, DCMIPP_P0FCTCR_CPTREQ);
--
2.34.1