Re: [PATCH v3 33/38] media: ti-vpe: cal: add camerarx locking

We don't have any locking in camerarx for the subdev ops. We have
managed fine so far without locking, but in the future multiple video
capture devices can use the same camerarx, and locking is a must.

Add a mutex to protect the camerarx subdev ops. Some of the functions
were slightly restructured to make lock handling cleaner.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/media/platform/ti-vpe/cal-camerarx.c | 81 ++++++++++++++------
 drivers/media/platform/ti-vpe/cal.h          |  3 +
 2 files changed, 61 insertions(+), 23 deletions(-)

diff --git a/drivers/media/platform/ti-vpe/cal-camerarx.c b/drivers/media/platform/ti-vpe/cal-camerarx.c
index 82392499e663..b87ffc52feb6 100644
--- a/drivers/media/platform/ti-vpe/cal-camerarx.c
+++ b/drivers/media/platform/ti-vpe/cal-camerarx.c

@@ -601,12 +601,18 @@ cal_camerarx_get_pad_format(struct cal_camerarx *phy,
 static int cal_camerarx_sd_s_stream(struct v4l2_subdev *sd, int enable)
 {
 	struct cal_camerarx *phy = to_cal_camerarx(sd);
+	int r = 0;

+
+	mutex_lock(&phy->mutex);
 
 	if (enable)
-		return cal_camerarx_start(phy);
+		r = cal_camerarx_start(phy);
+	else
+		cal_camerarx_stop(phy);
 
-	cal_camerarx_stop(phy);
-	return 0;
+	mutex_unlock(&phy->mutex);
+
+	return r;
 }
 
 static int cal_camerarx_sd_enum_mbus_code(struct v4l2_subdev *sd,

@@ -614,27 +620,36 @@ static int cal_camerarx_sd_enum_mbus_code(struct v4l2_subdev *sd,
 					  struct v4l2_subdev_mbus_code_enum *code)
 {
 	struct cal_camerarx *phy = to_cal_camerarx(sd);
+	int r = 0;
+
+	mutex_lock(&phy->mutex);
 
 	/* No transcoding, source and sink codes must match. */
 	if (code->pad == CAL_CAMERARX_PAD_SOURCE) {
 		struct v4l2_mbus_framefmt *fmt;
 
-		if (code->index > 0)
-			return -EINVAL;
+		if (code->index > 0) {
+			r = -EINVAL;
+			goto out;
+		}
 
 		fmt = cal_camerarx_get_pad_format(phy, sd_state,
 						  CAL_CAMERARX_PAD_SINK,
 						  code->which);
 		code->code = fmt->code;
-		return 0;
-	}
+	} else {
+		if (code->index >= cal_num_formats) {
+			r = -EINVAL;
+			goto out;
+		}
 
-	if (code->index >= cal_num_formats)
-		return -EINVAL;
+		code->code = cal_formats[code->index].code;
+	}
 
-	code->code = cal_formats[code->index].code;
+out:
+	mutex_unlock(&phy->mutex);
 
-	return 0;
+	return r;
 }
 
 static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,

@@ -643,10 +658,13 @@ static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,
 {
 	struct cal_camerarx *phy = to_cal_camerarx(sd);
 	const struct cal_format_info *fmtinfo;
+	int r = 0;
 
 	if (fse->index > 0)
 		return -EINVAL;
 
+	mutex_lock(&phy->mutex);
+
 	/* No transcoding, source and sink formats must match. */
 	if (fse->pad == CAL_CAMERARX_PAD_SOURCE) {
 		struct v4l2_mbus_framefmt *fmt;

@@ -654,27 +672,34 @@ static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,
 		fmt = cal_camerarx_get_pad_format(phy, sd_state,
 						  CAL_CAMERARX_PAD_SINK,
 						  fse->which);
-		if (fse->code != fmt->code)
-			return -EINVAL;
+		if (fse->code != fmt->code) {
+			r = -EINVAL;
+			goto out;
+		}
 
 		fse->min_width = fmt->width;
 		fse->max_width = fmt->width;
 		fse->min_height = fmt->height;
 		fse->max_height = fmt->height;
+	} else {
+		fmtinfo = cal_format_by_code(fse->code);
+		if (!fmtinfo) {
+			r = -EINVAL;
+			goto out;
+		}
 
-		return 0;
+		fse->min_width =
+			CAL_MIN_WIDTH_BYTES * 8 / ALIGN(fmtinfo->bpp, 8);
+		fse->max_width =
+			CAL_MAX_WIDTH_BYTES * 8 / ALIGN(fmtinfo->bpp, 8);

+		fse->min_height = CAL_MIN_HEIGHT_LINES;
+		fse->max_height = CAL_MAX_HEIGHT_LINES;
 	}
 
-	fmtinfo = cal_format_by_code(fse->code);
-	if (!fmtinfo)
-		return -EINVAL;
-
-	fse->min_width = CAL_MIN_WIDTH_BYTES * 8 / ALIGN(fmtinfo->bpp, 8);
-	fse->max_width = CAL_MAX_WIDTH_BYTES * 8 / ALIGN(fmtinfo->bpp, 8);
-	fse->min_height = CAL_MIN_HEIGHT_LINES;
-	fse->max_height = CAL_MAX_HEIGHT_LINES;
+out:
+	mutex_unlock(&phy->mutex);
 
-	return 0;
+	return r;
 }
 
 static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,

@@ -684,10 +709,14 @@ static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,
 	struct cal_camerarx *phy = to_cal_camerarx(sd);
 	struct v4l2_mbus_framefmt *fmt;
 
+	mutex_lock(&phy->mutex);
+
 	fmt = cal_camerarx_get_pad_format(phy, sd_state, format->pad,
 					  format->which);
 	format->format = *fmt;
 
+	mutex_unlock(&phy->mutex);
+
 	return 0;
 }
 

@@ -725,6 +754,8 @@ static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
 	format->format.field = V4L2_FIELD_NONE;
 
 	/* Store the format and propagate it to the source pad. */
+	mutex_lock(&phy->mutex);
+
 	fmt = cal_camerarx_get_pad_format(phy, sd_state,
 					  CAL_CAMERARX_PAD_SINK,
 					  format->which);

@@ -735,6 +766,8 @@ static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
 					  format->which);
 	*fmt = format->format;
 
+	mutex_unlock(&phy->mutex);
+
 	return 0;
 }
 

@@ -801,6 +834,8 @@ struct cal_camerarx *cal_camerarx_create(struct cal_dev *cal,
 	phy->cal = cal;
 	phy->instance = instance;
 
+	mutex_init(&phy->mutex);

+
 	phy->res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
 						(instance == 0) ?
 						"cal_rx_core0" :

diff --git a/drivers/media/platform/ti-vpe/cal.h b/drivers/media/platform/ti-vpe/cal.h
index ad08c189ad3b..78bd2e041d9a 100644
--- a/drivers/media/platform/ti-vpe/cal.h
+++ b/drivers/media/platform/ti-vpe/cal.h

@@ -163,6 +163,9 @@ struct cal_camerarx {
 	struct v4l2_subdev	subdev;
 	struct media_pad	pads[2];
 	struct v4l2_mbus_framefmt	formats[2];
+
+	/* mutex for camerarx ops */
+	struct mutex		mutex;