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[media] V4L: add two new ioctl()s for multi-size videobuffer management
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A possibility to preallocate and initialise buffers of different sizes
in V4L2 is required for an efficient implementation of a snapshot
mode. This patch adds two new ioctl()s: VIDIOC_CREATE_BUFS and
VIDIOC_PREPARE_BUF and defines respective data structures.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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@lyakh
lyakh authored and Mauro Carvalho Chehab committed Nov 3, 2011
1 parent ebc087d commit 2150158
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Showing 4 changed files with 115 additions and 8 deletions.
67 changes: 59 additions & 8 deletions drivers/media/video/v4l2-compat-ioctl32.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -159,11 +159,16 @@ struct v4l2_format32 {
} fmt;
};

static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
struct v4l2_create_buffers32 {
__u32 index; /* output: buffers index...index + count - 1 have been created */
__u32 count;
enum v4l2_memory memory;
struct v4l2_format32 format; /* filled in by the user, plane sizes calculated by the driver */
__u32 reserved[8];
};

static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
{
if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_format32)) ||
get_user(kp->type, &up->type))
return -EFAULT;
switch (kp->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
Expand Down Expand Up @@ -192,11 +197,24 @@ static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user
}
}

static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
{
if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_format32)) ||
get_user(kp->type, &up->type))
return -EFAULT;
return __get_v4l2_format32(kp, up);
}

static int get_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
{
if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_create_buffers32)) ||
copy_from_user(kp, up, offsetof(struct v4l2_create_buffers32, format.fmt)))
return -EFAULT;
return __get_v4l2_format32(&kp->format, &up->format);
}

static int __put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
{
if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_format32)) ||
put_user(kp->type, &up->type))
return -EFAULT;
switch (kp->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
Expand Down Expand Up @@ -225,6 +243,22 @@ static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user
}
}

static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
{
if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_format32)) ||
put_user(kp->type, &up->type))
return -EFAULT;
return __put_v4l2_format32(kp, up);
}

static int put_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
{
if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_create_buffers32)) ||
copy_to_user(up, kp, offsetof(struct v4l2_create_buffers32, format.fmt)))
return -EFAULT;
return __put_v4l2_format32(&kp->format, &up->format);
}

struct v4l2_standard32 {
__u32 index;
__u32 id[2]; /* __u64 would get the alignment wrong */
Expand Down Expand Up @@ -702,6 +736,8 @@ static int put_v4l2_event32(struct v4l2_event *kp, struct v4l2_event32 __user *u
#define VIDIOC_S_EXT_CTRLS32 _IOWR('V', 72, struct v4l2_ext_controls32)
#define VIDIOC_TRY_EXT_CTRLS32 _IOWR('V', 73, struct v4l2_ext_controls32)
#define VIDIOC_DQEVENT32 _IOR ('V', 89, struct v4l2_event32)
#define VIDIOC_CREATE_BUFS32 _IOWR('V', 92, struct v4l2_create_buffers32)
#define VIDIOC_PREPARE_BUF32 _IOWR('V', 93, struct v4l2_buffer32)

#define VIDIOC_OVERLAY32 _IOW ('V', 14, s32)
#define VIDIOC_STREAMON32 _IOW ('V', 18, s32)
Expand All @@ -721,6 +757,7 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
struct v4l2_standard v2s;
struct v4l2_ext_controls v2ecs;
struct v4l2_event v2ev;
struct v4l2_create_buffers v2crt;
unsigned long vx;
int vi;
} karg;
Expand Down Expand Up @@ -751,6 +788,8 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
case VIDIOC_S_INPUT32: cmd = VIDIOC_S_INPUT; break;
case VIDIOC_G_OUTPUT32: cmd = VIDIOC_G_OUTPUT; break;
case VIDIOC_S_OUTPUT32: cmd = VIDIOC_S_OUTPUT; break;
case VIDIOC_CREATE_BUFS32: cmd = VIDIOC_CREATE_BUFS; break;
case VIDIOC_PREPARE_BUF32: cmd = VIDIOC_PREPARE_BUF; break;
}

switch (cmd) {
Expand All @@ -775,6 +814,12 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
compatible_arg = 0;
break;

case VIDIOC_CREATE_BUFS:
err = get_v4l2_create32(&karg.v2crt, up);
compatible_arg = 0;
break;

case VIDIOC_PREPARE_BUF:
case VIDIOC_QUERYBUF:
case VIDIOC_QBUF:
case VIDIOC_DQBUF:
Expand Down Expand Up @@ -860,6 +905,10 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
err = put_v4l2_format32(&karg.v2f, up);
break;

case VIDIOC_CREATE_BUFS:
err = put_v4l2_create32(&karg.v2crt, up);
break;

case VIDIOC_QUERYBUF:
case VIDIOC_QBUF:
case VIDIOC_DQBUF:
Expand Down Expand Up @@ -959,6 +1008,8 @@ long v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg)
case VIDIOC_DQEVENT32:
case VIDIOC_SUBSCRIBE_EVENT:
case VIDIOC_UNSUBSCRIBE_EVENT:
case VIDIOC_CREATE_BUFS32:
case VIDIOC_PREPARE_BUF32:
ret = do_video_ioctl(file, cmd, arg);
break;

Expand Down
36 changes: 36 additions & 0 deletions drivers/media/video/v4l2-ioctl.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -273,6 +273,8 @@ 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_PREPARE_BUF)] = "VIDIOC_PREPARE_BUF",
};
#define V4L2_IOCTLS ARRAY_SIZE(v4l2_ioctls)

Expand Down Expand Up @@ -2104,6 +2106,40 @@ 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;
if (ret_prio) {
ret = ret_prio;
break;
}
ret = check_fmt(ops, create->format.type);
if (ret)
break;

ret = ops->vidioc_create_bufs(file, fh, create);

dbgarg(cmd, "count=%d @ %d\n", create->count, create->index);
break;
}
case VIDIOC_PREPARE_BUF:
{
struct v4l2_buffer *b = arg;

if (!ops->vidioc_prepare_buf)
break;
ret = check_fmt(ops, b->type);
if (ret)
break;

ret = ops->vidioc_prepare_buf(file, fh, b);

dbgarg(cmd, "index=%d", b->index);
break;
}
default:
if (!ops->vidioc_default)
break;
Expand Down
18 changes: 18 additions & 0 deletions include/linux/videodev2.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -653,6 +653,10 @@ struct v4l2_buffer {
#define V4L2_BUF_FLAG_ERROR 0x0040
#define V4L2_BUF_FLAG_TIMECODE 0x0100 /* timecode field is valid */
#define V4L2_BUF_FLAG_INPUT 0x0200 /* input field is valid */
#define V4L2_BUF_FLAG_PREPARED 0x0400 /* Buffer is prepared for queuing */
/* Cache handling flags */
#define V4L2_BUF_FLAG_NO_CACHE_INVALIDATE 0x0800
#define V4L2_BUF_FLAG_NO_CACHE_CLEAN 0x1000

/*
* O V E R L A Y P R E V I E W
Expand Down Expand Up @@ -2138,6 +2142,15 @@ struct v4l2_dbg_chip_ident {
__u32 revision; /* chip revision, chip specific */
} __attribute__ ((packed));

/* VIDIOC_CREATE_BUFS */
struct v4l2_create_buffers {
__u32 index; /* output: buffers index...index + count - 1 have been created */
__u32 count;
enum v4l2_memory memory;
struct v4l2_format format; /* "type" is used always, the rest if sizeimage == 0 */
__u32 reserved[8];
};

/*
* 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
*
Expand Down Expand Up @@ -2228,6 +2241,11 @@ 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)

/* Experimental, the below two ioctls may change over the next couple of kernel
versions */
#define VIDIOC_CREATE_BUFS _IOWR('V', 92, struct v4l2_create_buffers)
#define VIDIOC_PREPARE_BUF _IOWR('V', 93, struct v4l2_buffer)

/* Reminder: when adding new ioctls please add support for them to
drivers/media/video/v4l2-compat-ioctl32.c as well! */

Expand Down
2 changes: 2 additions & 0 deletions include/media/v4l2-ioctl.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -122,6 +122,8 @@ 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_prepare_buf)(struct file *file, void *fh, struct v4l2_buffer *b);

int (*vidioc_overlay) (struct file *file, void *fh, unsigned int i);
int (*vidioc_g_fbuf) (struct file *file, void *fh,
Expand Down

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