[PATCH/RFC v2 1/4] v4l: Add metadata buffer type and format

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The metadata buffer type is used to transfer metadata between userspace
and kernelspace through a V4L2 buffers queue. It comes with a new
metadata capture capability and format description.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
---
 Documentation/DocBook/media/v4l/dev-meta.xml  | 93 +++++++++++++++++++++++++++
 Documentation/DocBook/media/v4l/v4l2.xml      |  1 +
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 19 ++++++
 drivers/media/v4l2-core/v4l2-dev.c            | 16 +++--
 drivers/media/v4l2-core/v4l2-ioctl.c          | 34 ++++++++++
 drivers/media/v4l2-core/videobuf2-v4l2.c      |  3 +
 include/media/v4l2-ioctl.h                    |  8 +++
 include/uapi/linux/videodev2.h                | 14 ++++
 8 files changed, 182 insertions(+), 6 deletions(-)
 create mode 100644 Documentation/DocBook/media/v4l/dev-meta.xml

diff --git a/Documentation/DocBook/media/v4l/dev-meta.xml b/Documentation/DocBook/media/v4l/dev-meta.xml
new file mode 100644
index 000000000000..9b5b1fba2007
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/dev-meta.xml
@@ -0,0 +1,93 @@
+  <title>Metadata Interface</title>
+
+  <note>
+    <title>Experimental</title>
+    <para>This is an <link linkend="experimental"> experimental </link>
+    interface and may change in the future.</para>
+  </note>
+
+  <para>
+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.
+  </para>
+
+  <para>
+The metadata interface is implemented on video capture devices. The device can
+be dedicated to metadata or can implement both video and metadata capture as
+specified in its reported capabilities.
+  </para>
+
+  <section>
+    <title>Querying Capabilities</title>
+
+    <para>
+Devices supporting the metadata interface set the
+<constant>V4L2_CAP_META_CAPTURE</constant> flag in the
+<structfield>capabilities</structfield> field of &v4l2-capability;
+returned by the &VIDIOC-QUERYCAP; ioctl. That flag means the device can capture
+metadata to memory.
+    </para>
+    <para>
+At least one of the read/write or streaming I/O methods must be supported.
+    </para>
+  </section>
+
+  <section>
+    <title>Data Format Negotiation</title>
+
+    <para>
+The metadata device uses the <link linkend="format">format</link> ioctls to
+select the capture format. The metadata buffer content format is bound to that
+selectable format. In addition to the basic
+<link linkend="format">format</link> ioctls, the &VIDIOC-ENUM-FMT; ioctl
+must be supported as well.
+    </para>
+
+    <para>
+To use the <link linkend="format">format</link> ioctls applications set the
+<structfield>type</structfield> field of a &v4l2-format; to
+<constant>V4L2_BUF_TYPE_META_CAPTURE</constant> and use the &v4l2-meta-format;
+<structfield>meta</structfield> member of the <structfield>fmt</structfield>
+union as needed per the desired operation.
+Currently there are two fields, <structfield>dataformat</structfield> and
+<structfield>buffersize</structfield>, of struct &v4l2-meta-format; that are
+used. Content of the <structfield>dataformat</structfield> is the V4L2 FourCC
+code of the data format. The <structfield>buffersize</structfield> field is the
+maximum buffer size in bytes required for data transfer, set by the driver in
+order to inform applications.
+    </para>
+
+    <table pgwide="1" frame="none" id="v4l2-meta-format">
+      <title>struct <structname>v4l2_meta_format</structname></title>
+      <tgroup cols="3">
+        &cs-str;
+        <tbody valign="top">
+          <row>
+            <entry>__u32</entry>
+            <entry><structfield>dataformat</structfield></entry>
+            <entry>
+The data format, set by the application. This is a little endian
+<link linkend="v4l2-fourcc">four character code</link>.
+V4L2 defines metadata formats in <xref linkend="meta-formats" />.
+           </entry>
+          </row>
+          <row>
+            <entry>__u32</entry>
+            <entry><structfield>buffersize</structfield></entry>
+            <entry>
+Maximum size in bytes required for data. Value is set by the driver.
+           </entry>
+          </row>
+          <row>
+            <entry>__u8</entry>
+            <entry><structfield>reserved[24]</structfield></entry>
+            <entry>This array is reserved for future extensions.
+Drivers and applications must set it to zero.</entry>
+          </row>
+        </tbody>
+      </tgroup>
+    </table>
+
+  </section>
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml
index 42e626d6c936..5c83b5d342dd 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -605,6 +605,7 @@ and discussions on the V4L mailing list.</revremark>
     <section id="radio"> &sub-dev-radio; </section>
     <section id="rds"> &sub-dev-rds; </section>
     <section id="sdr"> &sub-dev-sdr; </section>
+    <section id="meta"> &sub-dev-meta; </section>
     <section id="event"> &sub-dev-event; </section>
     <section id="subdev"> &sub-dev-subdev; </section>
   </chapter>
diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index bacecbd68a6d..da2d836e8887 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -161,6 +161,20 @@ static inline int put_v4l2_sdr_format(struct v4l2_sdr_format *kp, struct v4l2_sd
 	return 0;
 }
 
+static inline int get_v4l2_meta_format(struct v4l2_meta_format *kp, struct v4l2_meta_format __user *up)
+{
+	if (copy_from_user(kp, up, sizeof(struct v4l2_meta_format)))
+		return -EFAULT;
+	return 0;
+}
+
+static inline int put_v4l2_meta_format(struct v4l2_meta_format *kp, struct v4l2_meta_format __user *up)
+{
+	if (copy_to_user(up, kp, sizeof(struct v4l2_meta_format)))
+		return -EFAULT;
+	return 0;
+}
+
 struct v4l2_format32 {
 	__u32	type;	/* enum v4l2_buf_type */
 	union {
@@ -170,6 +184,7 @@ struct v4l2_format32 {
 		struct v4l2_vbi_format	vbi;
 		struct v4l2_sliced_vbi_format	sliced;
 		struct v4l2_sdr_format	sdr;
+		struct v4l2_meta_format	meta;
 		__u8	raw_data[200];        /* user-defined */
 	} fmt;
 };
@@ -216,6 +231,8 @@ static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __us
 	case V4L2_BUF_TYPE_SDR_CAPTURE:
 	case V4L2_BUF_TYPE_SDR_OUTPUT:
 		return get_v4l2_sdr_format(&kp->fmt.sdr, &up->fmt.sdr);
+	case V4L2_BUF_TYPE_META_CAPTURE:
+		return get_v4l2_meta_format(&kp->fmt.meta, &up->fmt.meta);
 	default:
 		pr_info("compat_ioctl32: unexpected VIDIOC_FMT type %d\n",
 								kp->type);
@@ -263,6 +280,8 @@ static int __put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __us
 	case V4L2_BUF_TYPE_SDR_CAPTURE:
 	case V4L2_BUF_TYPE_SDR_OUTPUT:
 		return put_v4l2_sdr_format(&kp->fmt.sdr, &up->fmt.sdr);
+	case V4L2_BUF_TYPE_META_CAPTURE:
+		return put_v4l2_meta_format(&kp->fmt.meta, &up->fmt.meta);
 	default:
 		pr_info("compat_ioctl32: unexpected VIDIOC_FMT type %d\n",
 								kp->type);
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index 70b559d7ca80..74b79e60ac38 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -574,30 +574,34 @@ static void determine_valid_ioctls(struct video_device *vdev)
 		set_bit(_IOC_NR(VIDIOC_ENUM_FREQ_BANDS), valid_ioctls);
 
 	if (is_vid) {
-		/* video specific ioctls */
+		/* video and metadata specific ioctls */
 		if ((is_rx && (ops->vidioc_enum_fmt_vid_cap ||
 			       ops->vidioc_enum_fmt_vid_cap_mplane ||
-			       ops->vidioc_enum_fmt_vid_overlay)) ||
+			       ops->vidioc_enum_fmt_vid_overlay ||
+			       ops->vidioc_enum_fmt_meta_cap)) ||
 		    (is_tx && (ops->vidioc_enum_fmt_vid_out ||
 			       ops->vidioc_enum_fmt_vid_out_mplane)))
 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
 		if ((is_rx && (ops->vidioc_g_fmt_vid_cap ||
 			       ops->vidioc_g_fmt_vid_cap_mplane ||
-			       ops->vidioc_g_fmt_vid_overlay)) ||
+			       ops->vidioc_g_fmt_vid_overlay ||
+			       ops->vidioc_g_fmt_meta_cap)) ||
 		    (is_tx && (ops->vidioc_g_fmt_vid_out ||
 			       ops->vidioc_g_fmt_vid_out_mplane ||
 			       ops->vidioc_g_fmt_vid_out_overlay)))
 			 set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
 		if ((is_rx && (ops->vidioc_s_fmt_vid_cap ||
 			       ops->vidioc_s_fmt_vid_cap_mplane ||
-			       ops->vidioc_s_fmt_vid_overlay)) ||
+			       ops->vidioc_s_fmt_vid_overlay ||
+			       ops->vidioc_s_fmt_meta_cap)) ||
 		    (is_tx && (ops->vidioc_s_fmt_vid_out ||
 			       ops->vidioc_s_fmt_vid_out_mplane ||
 			       ops->vidioc_s_fmt_vid_out_overlay)))
 			 set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
 		if ((is_rx && (ops->vidioc_try_fmt_vid_cap ||
 			       ops->vidioc_try_fmt_vid_cap_mplane ||
-			       ops->vidioc_try_fmt_vid_overlay)) ||
+			       ops->vidioc_try_fmt_vid_overlay ||
+			       ops->vidioc_try_fmt_meta_cap)) ||
 		    (is_tx && (ops->vidioc_try_fmt_vid_out ||
 			       ops->vidioc_try_fmt_vid_out_mplane ||
 			       ops->vidioc_try_fmt_vid_out_overlay)))
@@ -663,7 +667,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
 	}
 
 	if (is_vid || is_vbi || is_sdr) {
-		/* ioctls valid for video, vbi or sdr */
+		/* ioctls valid for video, metadata, vbi or sdr */
 		SET_VALID_IOCTL(ops, VIDIOC_REQBUFS, vidioc_reqbufs);
 		SET_VALID_IOCTL(ops, VIDIOC_QUERYBUF, vidioc_querybuf);
 		SET_VALID_IOCTL(ops, VIDIOC_QBUF, vidioc_qbuf);
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 28e5be2c2eef..5d003152ff68 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -155,6 +155,7 @@ const char *v4l2_type_names[] = {
 	[V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE] = "vid-out-mplane",
 	[V4L2_BUF_TYPE_SDR_CAPTURE]        = "sdr-cap",
 	[V4L2_BUF_TYPE_SDR_OUTPUT]         = "sdr-out",
+	[V4L2_BUF_TYPE_META_CAPTURE]       = "meta-cap",
 };
 EXPORT_SYMBOL(v4l2_type_names);
 
@@ -249,6 +250,7 @@ static void v4l_print_format(const void *arg, bool write_only)
 	const struct v4l2_sliced_vbi_format *sliced;
 	const struct v4l2_window *win;
 	const struct v4l2_sdr_format *sdr;
+	const struct v4l2_meta_format *meta;
 	unsigned i;
 
 	pr_cont("type=%s", prt_names(p->type, v4l2_type_names));
@@ -336,6 +338,15 @@ static void v4l_print_format(const void *arg, bool write_only)
 			(sdr->pixelformat >> 16) & 0xff,
 			(sdr->pixelformat >> 24) & 0xff);
 		break;
+	case V4L2_BUF_TYPE_META_CAPTURE:
+		meta = &p->fmt.meta;
+		pr_cont(", dataformat=%c%c%c%c, buffersize=%u\n",
+			(meta->dataformat >>  0) & 0xff,
+			(meta->dataformat >>  8) & 0xff,
+			(meta->dataformat >> 16) & 0xff,
+			(meta->dataformat >> 24) & 0xff,
+			meta->buffersize);
+		break;
 	}
 }
 
@@ -981,6 +992,10 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
 		if (is_sdr && is_tx && ops->vidioc_g_fmt_sdr_out)
 			return 0;
 		break;
+	case V4L2_BUF_TYPE_META_CAPTURE:
+		if (is_vid && is_rx && ops->vidioc_g_fmt_meta_cap)
+			return 0;
+		break;
 	default:
 		break;
 	}
@@ -1349,6 +1364,11 @@ static int v4l_enum_fmt(const struct v4l2_ioctl_ops *ops,
 			break;
 		ret = ops->vidioc_enum_fmt_sdr_out(file, fh, arg);
 		break;
+	case V4L2_BUF_TYPE_META_CAPTURE:
+		if (unlikely(!is_rx || !is_vid || !ops->vidioc_enum_fmt_meta_cap))
+			break;
+		ret = ops->vidioc_enum_fmt_meta_cap(file, fh, arg);
+		break;
 	}
 	if (ret == 0)
 		v4l_fill_fmtdesc(p);
@@ -1447,6 +1467,10 @@ static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
 		if (unlikely(!is_tx || !is_sdr || !ops->vidioc_g_fmt_sdr_out))
 			break;
 		return ops->vidioc_g_fmt_sdr_out(file, fh, arg);
+	case V4L2_BUF_TYPE_META_CAPTURE:
+		if (unlikely(!is_rx || !is_vid || !ops->vidioc_g_fmt_meta_cap))
+			break;
+		return ops->vidioc_g_fmt_meta_cap(file, fh, arg);
 	}
 	return -EINVAL;
 }
@@ -1534,6 +1558,11 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
 			break;
 		CLEAR_AFTER_FIELD(p, fmt.sdr);
 		return ops->vidioc_s_fmt_sdr_out(file, fh, arg);
+	case V4L2_BUF_TYPE_META_CAPTURE:
+		if (unlikely(!is_rx || !is_vid || !ops->vidioc_s_fmt_meta_cap))
+			break;
+		CLEAR_AFTER_FIELD(p, fmt.meta);
+		return ops->vidioc_s_fmt_meta_cap(file, fh, arg);
 	}
 	return -EINVAL;
 }
@@ -1618,6 +1647,11 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
 			break;
 		CLEAR_AFTER_FIELD(p, fmt.sdr);
 		return ops->vidioc_try_fmt_sdr_out(file, fh, arg);
+	case V4L2_BUF_TYPE_META_CAPTURE:
+		if (unlikely(!is_rx || !is_vid || !ops->vidioc_try_fmt_meta_cap))
+			break;
+		CLEAR_AFTER_FIELD(p, fmt.meta);
+		return ops->vidioc_try_fmt_meta_cap(file, fh, arg);
 	}
 	return -EINVAL;
 }
diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c
index 7f366f1b0377..e4e90d9a3a65 100644
--- a/drivers/media/v4l2-core/videobuf2-v4l2.c
+++ b/drivers/media/v4l2-core/videobuf2-v4l2.c
@@ -575,6 +575,9 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
 	case V4L2_BUF_TYPE_SDR_OUTPUT:
 		requested_sizes[0] = f->fmt.sdr.buffersize;
 		break;
+	case V4L2_BUF_TYPE_META_CAPTURE:
+		requested_sizes[0] = f->fmt.meta.buffersize;
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index 017ffb2220c7..2dd00c73e892 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -38,6 +38,8 @@ struct v4l2_ioctl_ops {
 					    struct v4l2_fmtdesc *f);
 	int (*vidioc_enum_fmt_sdr_out)     (struct file *file, void *fh,
 					    struct v4l2_fmtdesc *f);
+	int (*vidioc_enum_fmt_meta_cap)    (struct file *file, void *fh,
+					    struct v4l2_fmtdesc *f);
 
 	/* VIDIOC_G_FMT handlers */
 	int (*vidioc_g_fmt_vid_cap)    (struct file *file, void *fh,
@@ -64,6 +66,8 @@ struct v4l2_ioctl_ops {
 					struct v4l2_format *f);
 	int (*vidioc_g_fmt_sdr_out)    (struct file *file, void *fh,
 					struct v4l2_format *f);
+	int (*vidioc_g_fmt_meta_cap)   (struct file *file, void *fh,
+					struct v4l2_format *f);
 
 	/* VIDIOC_S_FMT handlers */
 	int (*vidioc_s_fmt_vid_cap)    (struct file *file, void *fh,
@@ -90,6 +94,8 @@ struct v4l2_ioctl_ops {
 					struct v4l2_format *f);
 	int (*vidioc_s_fmt_sdr_out)    (struct file *file, void *fh,
 					struct v4l2_format *f);
+	int (*vidioc_s_fmt_meta_cap)   (struct file *file, void *fh,
+					struct v4l2_format *f);
 
 	/* VIDIOC_TRY_FMT handlers */
 	int (*vidioc_try_fmt_vid_cap)    (struct file *file, void *fh,
@@ -116,6 +122,8 @@ struct v4l2_ioctl_ops {
 					  struct v4l2_format *f);
 	int (*vidioc_try_fmt_sdr_out)    (struct file *file, void *fh,
 					  struct v4l2_format *f);
+	int (*vidioc_try_fmt_meta_cap)   (struct file *file, void *fh,
+					  struct v4l2_format *f);
 
 	/* Buffer handlers */
 	int (*vidioc_reqbufs) (struct file *file, void *fh, struct v4l2_requestbuffers *b);
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 8f951917be74..5fbd30ca9b1e 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -143,6 +143,7 @@ enum v4l2_buf_type {
 	V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE  = 10,
 	V4L2_BUF_TYPE_SDR_CAPTURE          = 11,
 	V4L2_BUF_TYPE_SDR_OUTPUT           = 12,
+	V4L2_BUF_TYPE_META_CAPTURE         = 13,
 	/* Deprecated, do not use */
 	V4L2_BUF_TYPE_PRIVATE              = 0x80,
 };
@@ -435,6 +436,7 @@ struct v4l2_capability {
 #define V4L2_CAP_SDR_CAPTURE		0x00100000  /* Is a SDR capture device */
 #define V4L2_CAP_EXT_PIX_FORMAT		0x00200000  /* Supports the extended pixel format */
 #define V4L2_CAP_SDR_OUTPUT		0x00400000  /* Is a SDR output device */
+#define V4L2_CAP_META_CAPTURE		0x00800000  /* Is a metadata capture device */
 
 #define V4L2_CAP_READWRITE              0x01000000  /* read/write systemcalls */
 #define V4L2_CAP_ASYNCIO                0x02000000  /* async I/O */
@@ -2000,6 +2002,17 @@ struct v4l2_sdr_format {
 } __attribute__ ((packed));
 
 /**
+ * struct v4l2_meta_format - metadata format definition
+ * @dataformat:		little endian four character code (fourcc)
+ * @buffersize:		maximum size in bytes required for data
+ */
+struct v4l2_meta_format {
+	__u32				dataformat;
+	__u32				buffersize;
+	__u8				reserved[24];
+} __attribute__ ((packed));
+
+/**
  * struct v4l2_format - stream data format
  * @type:	enum v4l2_buf_type; type of the data stream
  * @pix:	definition of an image format
@@ -2018,6 +2031,7 @@ struct v4l2_format {
 		struct v4l2_vbi_format		vbi;     /* V4L2_BUF_TYPE_VBI_CAPTURE */
 		struct v4l2_sliced_vbi_format	sliced;  /* V4L2_BUF_TYPE_SLICED_VBI_CAPTURE */
 		struct v4l2_sdr_format		sdr;     /* V4L2_BUF_TYPE_SDR_CAPTURE */
+		struct v4l2_meta_format		meta;    /* V4L2_BUF_TYPE_META_CAPTURE */
 		__u8	raw_data[200];                   /* user-defined */
 	} fmt;
 };
-- 
2.7.3




[Index of Archives]     [Linux Samsung SOC]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Device Mapper]

  Powered by Linux