media: staging: rkisp1: remove atomic operations for frame sequence

The isp.frame_sequence is now read only from the irq handlers
that are all fired from the same interrupt, so there is not need
for atomic operation.
In addition, the frame seq incrementation is moved from
rkisp1_isp_queue_event_sof to rkisp1_isp_isr to make the code
clearer and the incorrect inline comment is removed.
Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Acked-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/rkisp1/rkisp1-capture.c

@@ -674,7 +674,7 @@ static void rkisp1_handle_buffer(struct rkisp1_capture *cap)
 	curr_buf = cap->buf.curr;
 
 	if (curr_buf) {
-		curr_buf->vb.sequence = atomic_read(&isp->frame_sequence);
+		curr_buf->vb.sequence = isp->frame_sequence;
 		curr_buf->vb.vb2_buf.timestamp = ktime_get_boottime_ns();
 		curr_buf->vb.field = V4L2_FIELD_NONE;
 		vb2_buffer_done(&curr_buf->vb.vb2_buf, VB2_BUF_STATE_DONE);

drivers/staging/media/rkisp1/rkisp1-common.h

@@ -131,7 +131,7 @@ struct rkisp1_isp {
 	const struct rkisp1_isp_mbus_info *src_fmt;
 	struct mutex ops_lock; /* serialize the subdevice ops */
 	bool is_dphy_errctrl_disabled;
-	atomic_t frame_sequence;
+	__u32 frame_sequence;
 };
 
 /*

drivers/staging/media/rkisp1/rkisp1-isp.c

@@ -952,7 +952,7 @@ static int rkisp1_isp_s_stream(struct v4l2_subdev *sd, int enable)
 	if (rkisp1->active_sensor->mbus_type != V4L2_MBUS_CSI2_DPHY)
 		return -EINVAL;
 
-	atomic_set(&rkisp1->isp.frame_sequence, -1);
+	rkisp1->isp.frame_sequence = -1;
 	mutex_lock(&isp->ops_lock);
 	ret = rkisp1_config_cif(rkisp1);
 	if (ret)
@@ -1104,15 +1104,8 @@ static void rkisp1_isp_queue_event_sof(struct rkisp1_isp *isp)
 	struct v4l2_event event = {
 		.type = V4L2_EVENT_FRAME_SYNC,
 	};
+	event.u.frame_sync.frame_sequence = isp->frame_sequence;
 
-	/*
-	 * Increment the frame sequence on the vsync signal.
-	 * This will allow applications to detect dropped.
-	 * Note that there is a debugfs counter for dropped
-	 * frames, but using this event is more accurate.
-	 */
-	event.u.frame_sync.frame_sequence =
-		atomic_inc_return(&isp->frame_sequence);
 	v4l2_event_queue(isp->sd.devnode, &event);
 }
 
@@ -1127,9 +1120,10 @@ void rkisp1_isp_isr(struct rkisp1_device *rkisp1)
 	rkisp1_write(rkisp1, status, RKISP1_CIF_ISP_ICR);
 
 	/* Vertical sync signal, starting generating new frame */
-	if (status & RKISP1_CIF_ISP_V_START)
+	if (status & RKISP1_CIF_ISP_V_START) {
+		rkisp1->isp.frame_sequence++;
 		rkisp1_isp_queue_event_sof(&rkisp1->isp);
-
+	}
 	if (status & RKISP1_CIF_ISP_PIC_SIZE_ERROR) {
 		/* Clear pic_size_error */
 		isp_err = rkisp1_read(rkisp1, RKISP1_CIF_ISP_ERR);

drivers/staging/media/rkisp1/rkisp1-params.c

@@ -1220,7 +1220,7 @@ void rkisp1_params_isr(struct rkisp1_device *rkisp1)
 	 * frame_sequence + 1 here to indicate to userspace on which frame these parameters
 	 * are being applied.
 	 */
-	unsigned int frame_sequence = atomic_read(&rkisp1->isp.frame_sequence) + 1;
+	unsigned int frame_sequence = rkisp1->isp.frame_sequence + 1;
 	struct rkisp1_params *params = &rkisp1->params;
 
 	spin_lock(&params->config_lock);

drivers/staging/media/rkisp1/rkisp1-stats.c

@@ -307,8 +307,7 @@ rkisp1_stats_send_measurement(struct rkisp1_stats *stats, u32 isp_ris)
 {
 	struct rkisp1_stat_buffer *cur_stat_buf;
 	struct rkisp1_buffer *cur_buf = NULL;
-	unsigned int frame_sequence =
-		atomic_read(&stats->rkisp1->isp.frame_sequence);
+	unsigned int frame_sequence = stats->rkisp1->isp.frame_sequence;
 	u64 timestamp = ktime_get_ns();
 
 	/* get one empty buffer */