[RFC 03/11] v4l: subdev: Add [GS]_ROUTING subdev ioctls and operations

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Add support for subdev internal routing. A route is defined as a single
stream from a sink pad to a source pad.

The userspace can configure the routing via two new ioctls,
VIDIOC_SUBDEV_G_ROUTING and VIDIOC_SUBDEV_S_ROUTING, and subdevs can
implement the functionality with v4l2_subdev_pad_ops.get_routing() and
v4l2_subdev_pad_ops.set_routing().

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

- Add sink and source streams for multiplexed links
- Copy the argument back in case of an error. This is needed to let the
  caller know the number of routes.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

- Expand and refine documentation.
- Make the 'routes' pointer a __u64 __user pointer so that a compat32
  version of the ioctl is not required.
- Add struct v4l2_subdev_krouting to be used for subdevice operations.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

- Fix typecasing warnings
- Check sink & source pad types
- Add 'which' field

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/media/v4l2-core/v4l2-ioctl.c  | 25 +++++++++++++-
 drivers/media/v4l2-core/v4l2-subdev.c | 46 +++++++++++++++++++++++++
 include/media/v4l2-subdev.h           | 26 +++++++++++++++
 include/uapi/linux/v4l2-subdev.h      | 48 +++++++++++++++++++++++++++
 4 files changed, 144 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 6ed218f10522..9fb2812799ec 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -16,6 +16,7 @@
 #include <linux/kernel.h>
 #include <linux/version.h>
 
+#include <linux/v4l2-subdev.h>
 #include <linux/videodev2.h>
 
 #include <media/v4l2-common.h>
@@ -3110,6 +3111,21 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
 		ret = 1;
 		break;
 	}
+
+	case VIDIOC_SUBDEV_G_ROUTING:
+	case VIDIOC_SUBDEV_S_ROUTING: {
+		struct v4l2_subdev_routing *routing = parg;
+
+		if (routing->num_routes > 256)
+			return -EINVAL;
+
+		*user_ptr = u64_to_user_ptr(routing->routes);
+		*kernel_ptr = (void **)&routing->routes;
+		*array_size = sizeof(struct v4l2_subdev_route)
+			    * routing->num_routes;
+		ret = 1;
+		break;
+	}
 	}
 
 	return ret;
@@ -3371,8 +3387,15 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg,
 	/*
 	 * Some ioctls can return an error, but still have valid
 	 * results that must be returned.
+	 *
+	 * FIXME: subdev IOCTLS are partially handled here and partially in
+	 * v4l2-subdev.c and the 'always_copy' flag can only be set for IOCTLS
+	 * defined here as part of the 'v4l2_ioctls' array. As
+	 * VIDIOC_SUBDEV_G_ROUTING needs to return results to applications even
+	 * in case of failure, but it is not defined here as part of the
+	 * 'v4l2_ioctls' array, insert an ad-hoc check to address that.
 	 */
-	if (err < 0 && !always_copy)
+	if (err < 0 && !always_copy && cmd != VIDIOC_SUBDEV_G_ROUTING)
 		goto out;
 
 out_array_args:
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index bd996dcace3b..28e84453fe28 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -683,6 +683,52 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	case VIDIOC_SUBDEV_QUERYSTD:
 		return v4l2_subdev_call(sd, video, querystd, arg);
 
+	case VIDIOC_SUBDEV_G_ROUTING: {
+		struct v4l2_subdev_routing *routing = arg;
+		struct v4l2_subdev_krouting krouting = {
+			.which = routing->which,
+			.num_routes = routing->num_routes,
+			.routes = (struct v4l2_subdev_route *)(uintptr_t)
+					  routing->routes,
+		};
+		int ret;
+
+		ret = v4l2_subdev_call(sd, pad, get_routing, subdev_fh->state, &krouting);
+
+		routing->num_routes = krouting.num_routes;
+
+		return ret;
+	}
+
+	case VIDIOC_SUBDEV_S_ROUTING: {
+		struct v4l2_subdev_routing *routing = arg;
+		struct v4l2_subdev_route *routes =
+			(struct v4l2_subdev_route *)(uintptr_t)routing->routes;
+		struct v4l2_subdev_krouting krouting = {};
+		unsigned int i;
+
+		if (routing->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev)
+			return -EPERM;
+
+		for (i = 0; i < routing->num_routes; ++i) {
+			if (routes[i].sink_pad >= sd->entity.num_pads ||
+			    routes[i].source_pad >= sd->entity.num_pads)
+				return -EINVAL;
+
+			if (!(sd->entity.pads[routes[i].sink_pad].flags &
+			      MEDIA_PAD_FL_SINK) ||
+			    !(sd->entity.pads[routes[i].source_pad].flags &
+			      MEDIA_PAD_FL_SOURCE))
+				return -EINVAL;
+		}
+
+		krouting.which = routing->which;
+		krouting.num_routes = routing->num_routes;
+		krouting.routes = routes;
+
+		return v4l2_subdev_call(sd, pad, set_routing, subdev_fh->state, &krouting);
+	}
+
 	default:
 		return v4l2_subdev_call(sd, core, ioctl, cmd, arg);
 	}
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index a9c470605367..4cd1a3818c68 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -665,6 +665,22 @@ struct v4l2_subdev_pad_config {
 	struct v4l2_rect try_compose;
 };
 
+/**
+ * struct v4l2_subdev_krouting - subdev routing table
+ *
+ * @which: format type (from enum v4l2_subdev_format_whence)
+ * @routes: &struct v4l2_subdev_route
+ * @num_routes: number of routes
+ *
+ * This structure is used to translate arguments received from
+ * VIDIOC_SUBDEV_G/S_ROUTING() ioctl to subdev device drivers operations.
+ */
+struct v4l2_subdev_krouting {
+	u32 which;
+	struct v4l2_subdev_route *routes;
+	unsigned int num_routes;
+};
+
 /**
  * struct v4l2_subdev_state - Used for storing subdev information.
  *
@@ -739,6 +755,10 @@ struct v4l2_subdev_state {
  *		     applied to the hardware. The operation shall fail if the
  *		     pad index it has been called on is not valid or in case of
  *		     unrecoverable failures.
+ *
+ * @get_routing: get the subdevice routing table.
+ * @set_routing: enable or disable data connection routes described in the
+ *		 subdevice routing table.
  */
 struct v4l2_subdev_pad_ops {
 	int (*init_cfg)(struct v4l2_subdev *sd,
@@ -783,6 +803,12 @@ struct v4l2_subdev_pad_ops {
 			       struct v4l2_mbus_config *config);
 	int (*set_mbus_config)(struct v4l2_subdev *sd, unsigned int pad,
 			       struct v4l2_mbus_config *config);
+	int (*get_routing)(struct v4l2_subdev *sd,
+			   struct v4l2_subdev_state *state,
+			   struct v4l2_subdev_krouting *route);
+	int (*set_routing)(struct v4l2_subdev *sd,
+			   struct v4l2_subdev_state *state,
+			   struct v4l2_subdev_krouting *route);
 };
 
 /**
diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
index 658106f5b5dc..45c01799e2cd 100644
--- a/include/uapi/linux/v4l2-subdev.h
+++ b/include/uapi/linux/v4l2-subdev.h
@@ -188,6 +188,52 @@ struct v4l2_subdev_capability {
 /* The v4l2 sub-device video device node is registered in read-only mode. */
 #define V4L2_SUBDEV_CAP_RO_SUBDEV		0x00000001
 
+/**
+ * Is the route active? An active route will start when streaming is enabled
+ * on a video node.
+ */
+#define V4L2_SUBDEV_ROUTE_FL_ACTIVE		BIT(0)
+
+/**
+ * Is the route immutable, i.e. can it be activated and inactivated?
+ * Set by the driver.
+ */
+#define V4L2_SUBDEV_ROUTE_FL_IMMUTABLE		BIT(1)
+
+/**
+ * struct v4l2_subdev_route - A route inside a subdev
+ *
+ * @sink_pad: the sink pad index
+ * @sink_stream: the sink stream identifier
+ * @source_pad: the source pad index
+ * @source_stream: the source stream identifier
+ * @flags: route flags V4L2_SUBDEV_ROUTE_FL_*
+ * @reserved: drivers and applications must zero this array
+ */
+struct v4l2_subdev_route {
+	__u32 sink_pad;
+	__u32 sink_stream;
+	__u32 source_pad;
+	__u32 source_stream;
+	__u32 flags;
+	__u32 reserved[5];
+};
+
+/**
+ * struct v4l2_subdev_routing - Subdev routing information
+ *
+ * @which: configuration type (from enum v4l2_subdev_format_whence)
+ * @routes: pointer to the routes array
+ * @num_routes: the total number of routes in the routes array
+ * @reserved: drivers and applications must zero this array
+ */
+struct v4l2_subdev_routing {
+	__u32 which;
+	__u64 routes;
+	__u32 num_routes;
+	__u32 reserved[5];
+};
+
 /* Backwards compatibility define --- to be removed */
 #define v4l2_subdev_edid v4l2_edid
 
@@ -203,6 +249,8 @@ struct v4l2_subdev_capability {
 #define VIDIOC_SUBDEV_S_CROP			_IOWR('V', 60, struct v4l2_subdev_crop)
 #define VIDIOC_SUBDEV_G_SELECTION		_IOWR('V', 61, struct v4l2_subdev_selection)
 #define VIDIOC_SUBDEV_S_SELECTION		_IOWR('V', 62, struct v4l2_subdev_selection)
+#define VIDIOC_SUBDEV_G_ROUTING			_IOWR('V', 38, struct v4l2_subdev_routing)
+#define VIDIOC_SUBDEV_S_ROUTING			_IOWR('V', 39, struct v4l2_subdev_routing)
 /* The following ioctls are identical to the ioctls in videodev2.h */
 #define VIDIOC_SUBDEV_G_STD			_IOR('V', 23, v4l2_std_id)
 #define VIDIOC_SUBDEV_S_STD			_IOW('V', 24, v4l2_std_id)
-- 
2.25.1