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>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

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 ret = 0;
+
+	mutex_lock(&phy->mutex);
 
 	if (enable)
-		return cal_camerarx_start(phy);
+		ret = cal_camerarx_start(phy);
+	else
+		cal_camerarx_stop(phy);
 
-	cal_camerarx_stop(phy);
-	return 0;
+	mutex_unlock(&phy->mutex);
+
+	return ret;
 }
 
 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 ret = 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) {
+			ret = -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) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		code->code = cal_formats[code->index].code;
 	}
 
-	if (code->index >= cal_num_formats)
-		return -EINVAL;
+out:
+	mutex_unlock(&phy->mutex);
 
-	code->code = cal_formats[code->index].code;
-
-	return 0;
+	return ret;
 }
 
 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 ret = 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 +672,32 @@ 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) {
+			ret = -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) {
+			ret = -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;
+out:
+	mutex_unlock(&phy->mutex);
 
-	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;
-
-	return 0;
+	return ret;
 }
 
 static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,
@@ -684,10 +707,14 @@ 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 +752,9 @@ 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 +765,8 @@ static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
 					  format->which);
 	*fmt = format->format;
 
+	mutex_unlock(&phy->mutex);
+
 	return 0;
 }
 
@@ -801,6 +833,8 @@ 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" :
@@ -864,5 +898,6 @@ void cal_camerarx_destroy(struct cal_camerarx *phy)
 	media_entity_cleanup(&phy->subdev.entity);
 	of_node_put(phy->source_ep_node);
 	of_node_put(phy->source_node);
+	mutex_destroy(&phy->mutex);
 	kfree(phy);
 }

drivers/media/platform/ti-vpe/cal.h

@@ -163,6 +163,12 @@ struct cal_camerarx {
 	struct v4l2_subdev	subdev;
 	struct media_pad	pads[2];
 	struct v4l2_mbus_framefmt	formats[2];
+
+	/*
+	 * Lock for camerarx ops. Protects:
+	 * - formats
+	 */
+	struct mutex		mutex;
 };
 
 struct cal_dev {