[PATCH 0/2] Add V4L2_BUF_TYPE_META_OUTPUT buffer type

@@ -235,6 +235,7 @@ static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __us
 	case V4L2_BUF_TYPE_SDR_OUTPUT:
 		return get_v4l2_sdr_format(&kp->fmt.sdr, &up->fmt.sdr);
 	case V4L2_BUF_TYPE_META_CAPTURE:
+	case V4L2_BUF_TYPE_META_OUTPUT:
 		return get_v4l2_meta_format(&kp->fmt.meta, &up->fmt.meta);
 	default:
 		pr_info("compat_ioctl32: unexpected VIDIOC_FMT type %d\n",

@@ -284,6 +285,7 @@ static int __put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __us
 	case V4L2_BUF_TYPE_SDR_OUTPUT:
 		return put_v4l2_sdr_format(&kp->fmt.sdr, &up->fmt.sdr);
 	case V4L2_BUF_TYPE_META_CAPTURE:
+	case V4L2_BUF_TYPE_META_OUTPUT:
 		return put_v4l2_meta_format(&kp->fmt.meta, &up->fmt.meta);
 	default:
 		pr_info("compat_ioctl32: unexpected VIDIOC_FMT type %d\n",

@@ -157,6 +157,7 @@ const char *v4l2_type_names[] = {
 	[V4L2_BUF_TYPE_SDR_CAPTURE]        = "sdr-cap",
 	[V4L2_BUF_TYPE_SDR_OUTPUT]         = "sdr-out",
 	[V4L2_BUF_TYPE_META_CAPTURE]       = "meta-cap",
+	[V4L2_BUF_TYPE_META_OUTPUT]	   = "meta-out",
 };
 EXPORT_SYMBOL(v4l2_type_names);
 

@@ -329,6 +330,7 @@ static void v4l_print_format(const void *arg, bool write_only)
 			(sdr->pixelformat >> 24) & 0xff);
 		break;
 	case V4L2_BUF_TYPE_META_CAPTURE:
+	case V4L2_BUF_TYPE_META_OUTPUT:
 		meta = &p->fmt.meta;
 		pr_cont(", dataformat=%c%c%c%c, buffersize=%u\n",
 			(meta->dataformat >>  0) & 0xff,

@@ -959,6 +961,10 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
 		if (is_vid && is_rx && ops->vidioc_g_fmt_meta_cap)
 			return 0;
 		break;
+	case V4L2_BUF_TYPE_META_OUTPUT:
+		if (is_vid && is_tx && ops->vidioc_g_fmt_meta_out)
+			return 0;
+		break;
 	default:
 		break;
 	}

@@ -1353,6 +1359,11 @@ static int v4l_enum_fmt(const struct v4l2_ioctl_ops *ops,
 			break;
 		ret = ops->vidioc_enum_fmt_meta_cap(file, fh, arg);
 		break;
+	case V4L2_BUF_TYPE_META_OUTPUT:
+		if (unlikely(!is_tx || !is_vid || !ops->vidioc_enum_fmt_meta_out))
+			break;
+		ret = ops->vidioc_enum_fmt_meta_out(file, fh, arg);
+		break;
 	}
 	if (ret == 0)
 		v4l_fill_fmtdesc(p);

@@ -1456,6 +1467,10 @@ static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
 		if (unlikely(!is_rx || !is_vid || !ops->vidioc_g_fmt_meta_cap))
 			break;
 		return ops->vidioc_g_fmt_meta_cap(file, fh, arg);
+	case V4L2_BUF_TYPE_META_OUTPUT:
+		if (unlikely(!is_tx || !is_vid || !ops->vidioc_g_fmt_meta_out))
+			break;
+		return ops->vidioc_g_fmt_meta_out(file, fh, arg);
 	}
 	return -EINVAL;
 }

@@ -1566,6 +1581,11 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
 			break;
 		CLEAR_AFTER_FIELD(p, fmt.meta);
 		return ops->vidioc_s_fmt_meta_cap(file, fh, arg);
+	case V4L2_BUF_TYPE_META_OUTPUT:
+		if (unlikely(!is_tx || !is_vid || !ops->vidioc_s_fmt_meta_out))
+			break;
+		CLEAR_AFTER_FIELD(p, fmt.meta);
+		return ops->vidioc_s_fmt_meta_out(file, fh, arg);
 	}
 	return -EINVAL;
 }

@@ -1656,6 +1676,11 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
 			break;
 		CLEAR_AFTER_FIELD(p, fmt.meta);
 		return ops->vidioc_try_fmt_meta_cap(file, fh, arg);
+	case V4L2_BUF_TYPE_META_OUTPUT:
+		if (unlikely(!is_tx || !is_vid || !ops->vidioc_try_fmt_meta_out))
+			break;
+		CLEAR_AFTER_FIELD(p, fmt.meta);
+		return ops->vidioc_try_fmt_meta_out(file, fh, arg);
 	}
 	return -EINVAL;
 }

@@ -545,6 +545,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
 		requested_sizes[0] = f->fmt.sdr.buffersize;
 		break;
 	case V4L2_BUF_TYPE_META_CAPTURE:
+	case V4L2_BUF_TYPE_META_OUTPUT:
 		requested_sizes[0] = f->fmt.meta.buffersize;
 		break;
 	default:

@@ -47,6 +47,9 @@ struct v4l2_fh;
  * @vidioc_enum_fmt_meta_cap: pointer to the function that implements
  *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
  *	for metadata capture
+ * @vidioc_enum_fmt_meta_out: pointer to the function that implements
+ *	:ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
+ *	for metadata output
  * @vidioc_g_fmt_vid_cap: pointer to the function that implements
  *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for video capture
  *	in single plane mode

@@ -79,6 +82,8 @@ struct v4l2_fh;
  *	Radio output
  * @vidioc_g_fmt_meta_cap: pointer to the function that implements
  *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
+ * @vidioc_g_fmt_meta_out: pointer to the function that implements
+ *	:ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata output
  * @vidioc_s_fmt_vid_cap: pointer to the function that implements
  *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for video capture
  *	in single plane mode

@@ -111,6 +116,8 @@ struct v4l2_fh;
  *	Radio output
  * @vidioc_s_fmt_meta_cap: pointer to the function that implements
  *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
+ * @vidioc_s_fmt_meta_out: pointer to the function that implements
+ *	:ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata output
  * @vidioc_try_fmt_vid_cap: pointer to the function that implements
  *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for video capture
  *	in single plane mode

@@ -145,6 +152,8 @@ struct v4l2_fh;
  *	Radio output
  * @vidioc_try_fmt_meta_cap: pointer to the function that implements
  *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
+ * @vidioc_try_fmt_meta_out: pointer to the function that implements
+ *	:ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata output
  * @vidioc_reqbufs: pointer to the function that implements
  *	:ref:`VIDIOC_REQBUFS <vidioc_reqbufs>` ioctl
  * @vidioc_querybuf: pointer to the function that implements

@@ -317,6 +326,8 @@ struct v4l2_ioctl_ops {
 				       struct v4l2_fmtdesc *f);
 	int (*vidioc_enum_fmt_meta_cap)(struct file *file, void *fh,
 					struct v4l2_fmtdesc *f);
+	int (*vidioc_enum_fmt_meta_out)(struct file *file, void *fh,
+					struct v4l2_fmtdesc *f);
 
 	/* VIDIOC_G_FMT handlers */
 	int (*vidioc_g_fmt_vid_cap)(struct file *file, void *fh,

@@ -345,6 +356,8 @@ struct v4l2_ioctl_ops {
 				    struct v4l2_format *f);
 	int (*vidioc_g_fmt_meta_cap)(struct file *file, void *fh,
 				     struct v4l2_format *f);
+	int (*vidioc_g_fmt_meta_out)(struct file *file, void *fh,
+				     struct v4l2_format *f);
 
 	/* VIDIOC_S_FMT handlers */
 	int (*vidioc_s_fmt_vid_cap)(struct file *file, void *fh,

@@ -373,6 +386,8 @@ struct v4l2_ioctl_ops {
 				    struct v4l2_format *f);
 	int (*vidioc_s_fmt_meta_cap)(struct file *file, void *fh,
 				     struct v4l2_format *f);
+	int (*vidioc_s_fmt_meta_out)(struct file *file, void *fh,
+				     struct v4l2_format *f);
 
 	/* VIDIOC_TRY_FMT handlers */
 	int (*vidioc_try_fmt_vid_cap)(struct file *file, void *fh,

@@ -401,6 +416,8 @@ struct v4l2_ioctl_ops {
 				      struct v4l2_format *f);
 	int (*vidioc_try_fmt_meta_cap)(struct file *file, void *fh,
 				       struct v4l2_format *f);
+	int (*vidioc_try_fmt_meta_out)(struct file *file, void *fh,
+				       struct v4l2_format *f);
 
 	/* Buffer handlers */
 	int (*vidioc_reqbufs)(struct file *file, void *fh,

@@ -144,6 +144,7 @@ enum v4l2_buf_type {
 	V4L2_BUF_TYPE_SDR_CAPTURE          = 11,
 	V4L2_BUF_TYPE_SDR_OUTPUT           = 12,
 	V4L2_BUF_TYPE_META_CAPTURE         = 13,
+	V4L2_BUF_TYPE_META_OUTPUT	   = 14,
 	/* Deprecated, do not use */
 	V4L2_BUF_TYPE_PRIVATE              = 0x80,
 };

@@ -457,6 +458,7 @@ struct v4l2_capability {
 #define V4L2_CAP_READWRITE              0x01000000  /* read/write systemcalls */
 #define V4L2_CAP_ASYNCIO                0x02000000  /* async I/O */
 #define V4L2_CAP_STREAMING              0x04000000  /* streaming I/O ioctls */
+#define V4L2_CAP_META_OUTPUT		0x08000000  /* Is a metadata output device */
 
 #define V4L2_CAP_TOUCH                  0x10000000  /* Is a touch device */
 

@@ -452,6 +452,9 @@ enum v4l2_buf_type
     * - ``V4L2_BUF_TYPE_META_CAPTURE``
       - 13
       - Buffer for metadata capture, see :ref:`metadata`.
+    * - ``V4L2_BUF_TYPE_META_OUTPUT``
+      - 14
+      - Buffer for metadata output, see :ref:`metadata`.
 
 
 

@@ -7,21 +7,27 @@ Metadata Interface
 ******************
 
 Metadata refers to any non-image data that supplements video frames with
-additional information. This may include statistics computed over the image
-or frame capture parameters supplied by the image source. This interface is
-intended for transfer of metadata to userspace and control of that operation.
+additional information. This may include statistics computed over the image,
+frame capture parameters supplied by the image source or device specific
+parameters for specifying how the device processes images. This interface is
+intended for transfer of metadata between the userspace and the hardware and
+control of that operation.
 
-The metadata interface is implemented on video capture device nodes. The device
-can be dedicated to metadata or can implement both video and metadata capture
-as specified in its reported capabilities.
+The metadata interface is implemented on video device nodes. The device can be
+dedicated to metadata or can support both video and metadata as specified in its
+reported capabilities.
 
 Querying Capabilities
 =====================
 
-Device nodes supporting the metadata interface set the ``V4L2_CAP_META_CAPTURE``
-flag in the ``device_caps`` field of the
+Device nodes supporting the metadata capture interface set the
+``V4L2_CAP_META_CAPTURE`` flag in the ``device_caps`` field of the
 :c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP`
-ioctl. That flag means the device can capture metadata to memory.
+ioctl. That flag means the device can capture metadata to memory. Similarly,
+device nodes supporting metadata output interface set the
+``V4L2_CAP_META_OUTPUT`` flag in the ``device_caps`` field of
+:c:type:`v4l2_capability` structure. That flag means the device can read
+metadata from memory.
 
 At least one of the read/write or streaming I/O methods must be supported.
 

@@ -35,10 +41,11 @@ to the basic :ref:`format` ioctls, the :c:func:`VIDIOC_ENUM_FMT` ioctl must be
 supported as well.
 
 To use the :ref:`format` ioctls applications set the ``type`` field of the
-:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_META_CAPTURE`` and use the
-:c:type:`v4l2_meta_format` ``meta`` member of the ``fmt`` union as needed per
-the desired operation. Both drivers and applications must set the remainder of
-the :c:type:`v4l2_format` structure to 0.
+:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_META_CAPTURE`` or to
+``V4L2_BUF_TYPE_META_OUTPUT`` and use the :c:type:`v4l2_meta_format` ``meta``
+member of the ``fmt`` union as needed per the desired operation. Both drivers
+and applications must set the remainder of the :c:type:`v4l2_format` structure
+to 0.
 
 .. _v4l2-meta-format:
 

@@ -249,6 +249,9 @@ specification the ioctl returns an ``EINVAL`` error code.
     * - ``V4L2_CAP_STREAMING``
       - 0x04000000
       - The device supports the :ref:`streaming <mmap>` I/O method.
+    * - ``V4L2_CAP_META_OUTPUT``
+      - 0x08000000
+      - The device supports the :ref:`metadata` output interface.
     * - ``V4L2_CAP_TOUCH``
       - 0x10000000
       - This is a touch device.

@@ -28,6 +28,7 @@ replace symbol V4L2_FIELD_TOP :c:type:`v4l2_field`
 
 # Documented enum v4l2_buf_type
 replace symbol V4L2_BUF_TYPE_META_CAPTURE :c:type:`v4l2_buf_type`
+replace symbol V4L2_BUF_TYPE_META_OUTPUT :c:type:`v4l2_buf_type`
 replace symbol V4L2_BUF_TYPE_SDR_CAPTURE :c:type:`v4l2_buf_type`
 replace symbol V4L2_BUF_TYPE_SDR_OUTPUT :c:type:`v4l2_buf_type`
 replace symbol V4L2_BUF_TYPE_SLICED_VBI_CAPTURE :c:type:`v4l2_buf_type`

@@ -157,6 +158,7 @@ replace define V4L2_CAP_META_CAPTURE device-capabilities
 replace define V4L2_CAP_READWRITE device-capabilities
 replace define V4L2_CAP_ASYNCIO device-capabilities
 replace define V4L2_CAP_STREAMING device-capabilities
+replace define V4L2_CAP_META_OUTPUT device-capabilities
 replace define V4L2_CAP_DEVICE_CAPS device-capabilities
 replace define V4L2_CAP_TOUCH device-capabilities