[PATCH/RFC 1/4] V4L: add three new ioctl()s for multi-size videobuffer management

[Guennadi Liakhovetski <g.liakhovetski@gmx.de>]

A possibility to preallocate and initialise buffers of different sizes
in V4L2 is required for an efficient implementation of asnapshot mode.
This patch adds three new ioctl()s: VIDIOC_CREATE_BUFS,
VIDIOC_DESTROY_BUFS, and VIDIOC_SUBMIT_BUF and defines respective data
structures.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---
 drivers/media/video/v4l2-compat-ioctl32.c |    3 ++
 drivers/media/video/v4l2-ioctl.c          |   43 +++++++++++++++++++++++++++++
 include/linux/videodev2.h                 |   24 ++++++++++++++++
 include/media/v4l2-ioctl.h                |    3 ++
 4 files changed, 73 insertions(+), 0 deletions(-)

diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
index 7c26947..d71b289 100644
--- a/drivers/media/video/v4l2-compat-ioctl32.c
+++ b/drivers/media/video/v4l2-compat-ioctl32.c
@@ -922,6 +922,9 @@ long v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg)
 	case VIDIOC_DQEVENT:
 	case VIDIOC_SUBSCRIBE_EVENT:
 	case VIDIOC_UNSUBSCRIBE_EVENT:
+	case VIDIOC_CREATE_BUFS:
+	case VIDIOC_DESTROY_BUFS:
+	case VIDIOC_SUBMIT_BUF:
 		ret = do_video_ioctl(file, cmd, arg);
 		break;
 
diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index a01ed39..b80a211 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -259,6 +259,9 @@ static const char *v4l2_ioctls[] = {
 	[_IOC_NR(VIDIOC_DQEVENT)]	   = "VIDIOC_DQEVENT",
 	[_IOC_NR(VIDIOC_SUBSCRIBE_EVENT)]  = "VIDIOC_SUBSCRIBE_EVENT",
 	[_IOC_NR(VIDIOC_UNSUBSCRIBE_EVENT)] = "VIDIOC_UNSUBSCRIBE_EVENT",
+	[_IOC_NR(VIDIOC_CREATE_BUFS)]      = "VIDIOC_CREATE_BUFS",
+	[_IOC_NR(VIDIOC_DESTROY_BUFS)]     = "VIDIOC_DESTROY_BUFS",
+	[_IOC_NR(VIDIOC_SUBMIT_BUF)]       = "VIDIOC_SUBMIT_BUF",
 };
 #define V4L2_IOCTLS ARRAY_SIZE(v4l2_ioctls)
 
@@ -2184,6 +2187,46 @@ static long __video_do_ioctl(struct file *file,
 		dbgarg(cmd, "type=0x%8.8x", sub->type);
 		break;
 	}
+	case VIDIOC_CREATE_BUFS:
+	{
+		struct v4l2_create_buffers *create = arg;
+
+		if (!ops->vidioc_create_bufs)
+			break;
+		ret = check_fmt(ops, create->format.type);
+		if (ret)
+			break;
+
+		if (create->size)
+			CLEAR_AFTER_FIELD(create, count);
+
+		ret = ops->vidioc_create_bufs(file, fh, create);
+
+		dbgarg(cmd, "count=%d\n", create->count);
+		break;
+	}
+	case VIDIOC_DESTROY_BUFS:
+	{
+		struct v4l2_buffer_span *span = arg;
+
+		if (!ops->vidioc_destroy_bufs)
+			break;
+
+		ret = ops->vidioc_destroy_bufs(file, fh, span);
+
+		dbgarg(cmd, "count=%d", span->count);
+		break;
+	}
+	case VIDIOC_SUBMIT_BUF:
+	{
+		unsigned int *i = arg;
+
+		if (!ops->vidioc_submit_buf)
+			break;
+		ret = ops->vidioc_submit_buf(file, fh, *i);
+		dbgarg(cmd, "index=%d", *i);
+		break;
+	}
 	default:
 	{
 		bool valid_prio = true;
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index aa6c393..b6ef46e 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -1847,6 +1847,26 @@ struct v4l2_dbg_chip_ident {
 	__u32 revision;    /* chip revision, chip specific */
 } __attribute__ ((packed));
 
+/* VIDIOC_DESTROY_BUFS */
+struct v4l2_buffer_span {
+	__u32			index;	/* output: buffers index...index + count - 1 have been created */
+	__u32			count;
+	__u32			reserved[2];
+};
+
+/* struct v4l2_createbuffers::flags */
+#define V4L2_BUFFER_FLAG_NO_CACHE_INVALIDATE	(1 << 0)
+
+/* VIDIOC_CREATE_BUFS */
+struct v4l2_create_buffers {
+	__u32			index;		/* output: buffers index...index + count - 1 have been created */
+	__u32			count;
+	__u32			flags;		/* V4L2_BUFFER_FLAG_* */
+	enum v4l2_memory        memory;
+	__u32			size;		/* Explicit size, e.g., for compressed streams */
+	struct v4l2_format	format;		/* "type" is used always, the rest if size == 0 */
+};
+
 /*
  *	I O C T L   C O D E S   F O R   V I D E O   D E V I C E S
  *
@@ -1937,6 +1957,10 @@ struct v4l2_dbg_chip_ident {
 #define	VIDIOC_SUBSCRIBE_EVENT	 _IOW('V', 90, struct v4l2_event_subscription)
 #define	VIDIOC_UNSUBSCRIBE_EVENT _IOW('V', 91, struct v4l2_event_subscription)
 
+#define VIDIOC_CREATE_BUFS	_IOWR('V', 92, struct v4l2_create_buffers)
+#define VIDIOC_DESTROY_BUFS	_IOWR('V', 93, struct v4l2_buffer_span)
+#define VIDIOC_SUBMIT_BUF	 _IOW('V', 94, int)
+
 /* Reminder: when adding new ioctls please add support for them to
    drivers/media/video/v4l2-compat-ioctl32.c as well! */
 
diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index dd9f1e7..00962c6 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -122,6 +122,9 @@ struct v4l2_ioctl_ops {
 	int (*vidioc_qbuf)    (struct file *file, void *fh, struct v4l2_buffer *b);
 	int (*vidioc_dqbuf)   (struct file *file, void *fh, struct v4l2_buffer *b);
 
+	int (*vidioc_create_bufs) (struct file *file, void *fh, struct v4l2_create_buffers *b);
+	int (*vidioc_destroy_bufs)(struct file *file, void *fh, struct v4l2_buffer_span *b);
+	int (*vidioc_submit_buf)  (struct file *file, void *fh, unsigned int i);
 
 	int (*vidioc_overlay) (struct file *file, void *fh, unsigned int i);
 	int (*vidioc_g_fbuf)   (struct file *file, void *fh,
-- 
1.7.2.5