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v4l2loopback.c
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v4l2loopback.c
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/* -*- c-file-style: "linux" -*- */
/*
* v4l2loopback.c -- video4linux2 loopback driver
*
* Copyright (C) 2005-2009 Vasily Levin (vasaka@gmail.com)
* Copyright (C) 2010-2019 IOhannes m zmoelnig (zmoelnig@iem.at)
* Copyright (C) 2011 Stefan Diewald (stefan.diewald@mytum.de)
* Copyright (C) 2012 Anton Novikov (random.plant@gmail.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
*/
#include <linux/version.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/time.h>
#include <linux/module.h>
#include <linux/videodev2.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-common.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 29)
# define HAVE__V4L2_DEVICE
# include <media/v4l2-device.h>
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 36)
# define HAVE__V4L2_CTRLS
# include <media/v4l2-ctrls.h>
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(3,6,1)
# define kstrtoul strict_strtoul
#endif
#if defined(timer_setup) && defined(from_timer)
#define HAVE_TIMER_SETUP
#endif
#define V4L2LOOPBACK_VERSION_CODE KERNEL_VERSION(0, 12, 3)
MODULE_DESCRIPTION("V4L2 loopback video device");
MODULE_AUTHOR("Vasily Levin, " \
"IOhannes m zmoelnig <zmoelnig@iem.at>," \
"Stefan Diewald," \
"Anton Novikov" \
"et al." \
);
MODULE_LICENSE("GPL");
/*
* helpers
*/
#define STRINGIFY(s) #s
#define STRINGIFY2(s) STRINGIFY(s)
#define dprintk(fmt, args...) \
do { if (debug > 0) { \
printk(KERN_INFO "v4l2-loopback[" STRINGIFY2(__LINE__) "]: " fmt, ##args); \
} } while (0)
#define MARK() \
do { if (debug > 1) { \
printk(KERN_INFO "%s:%d[%s]\n", __FILE__, __LINE__, __func__); \
} } while (0)
#define dprintkrw(fmt, args...) \
do { if (debug > 2) { \
printk(KERN_INFO "v4l2-loopback[" STRINGIFY2(__LINE__)"]: " fmt, ##args); \
} } while (0)
/*
* compatibility hacks
*/
#ifndef HAVE__V4L2_CTRLS
struct v4l2_ctrl_handler {
int error;
};
struct v4l2_ctrl_config {
void *ops;
u32 id;
const char *name;
int type;
s32 min;
s32 max;
u32 step;
s32 def;
};
int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler*hdl,
unsigned nr_of_controls_hint)
{
hdl->error=0;
return 0;
}
void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
{
}
void*v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
const struct v4l2_ctrl_config*conf,
void*priv)
{
return NULL;
}
#endif /* HAVE__V4L2_CTRLS */
#ifndef HAVE__V4L2_DEVICE
/* dummy v4l2_device struct/functions */
# define V4L2_DEVICE_NAME_SIZE (20 + 16)
struct v4l2_device {
char name[V4L2_DEVICE_NAME_SIZE];
struct v4l2_ctrl_handler*ctrl_handler;
};
static inline int v4l2_device_register (void *dev, void *v4l2_dev) { return 0; }
static inline void v4l2_device_unregister(struct v4l2_device *v4l2_dev) { return; }
#endif /* HAVE__V4L2_DEVICE */
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 29)
# define v4l2_file_operations file_operations
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 37)
void *v4l2l_vzalloc(unsigned long size)
{
void *data = vmalloc(size);
memset(data, 0, size);
return data;
}
#else
# define v4l2l_vzalloc vzalloc
#endif
static inline void v4l2l_get_timestamp(struct v4l2_buffer *b) {
/* ktime_get_ts is considered deprecated, so use ktime_get_ts64 if possible */
#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 17, 0)
struct timespec ts;
ktime_get_ts(&ts);
#else
struct timespec64 ts;
ktime_get_ts64(&ts);
#endif
b->timestamp.tv_sec = ts.tv_sec;
b->timestamp.tv_usec = (ts.tv_nsec / NSEC_PER_USEC);
}
/* module constants
* can be overridden during he build process using something like
* make KCPPFLAGS="-DMAX_DEVICES=100"
*/
/* maximum number of v4l2loopback devices that can be created */
#ifndef MAX_DEVICES
# define MAX_DEVICES 8
#endif
/* when a producer is considered to have gone stale */
#ifndef MAX_TIMEOUT
# define MAX_TIMEOUT (100 * 1000) /* in msecs */
#endif
/* max buffers that can be mapped, actually they
* are all mapped to max_buffers buffers */
#ifndef MAX_BUFFERS
# define MAX_BUFFERS 32
#endif
/* module parameters */
static int debug = 0;
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "debugging level (higher values == more verbose)");
static int max_buffers = 2;
module_param(max_buffers, int, S_IRUGO);
MODULE_PARM_DESC(max_buffers, "how many buffers should be allocated");
/* how many times a device can be opened
* the per-module default value can be overridden on a per-device basis using
* the /sys/devices interface
*
* note that max_openers should be at least 2 in order to get a working system:
* one opener for the producer and one opener for the consumer
* however, we leave that to the user
*/
static int max_openers = 10;
module_param(max_openers, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(max_openers, "how many users can open loopback device");
static int devices = -1;
module_param(devices, int, 0);
MODULE_PARM_DESC(devices, "how many devices should be created");
static int video_nr[MAX_DEVICES] = { [0 ... (MAX_DEVICES - 1)] = -1 };
module_param_array(video_nr, int, NULL, 0444);
MODULE_PARM_DESC(video_nr, "video device numbers (-1=auto, 0=/dev/video0, etc.)");
static char *card_label[MAX_DEVICES];
module_param_array(card_label, charp, NULL, 0000);
MODULE_PARM_DESC(card_label, "card labels for every device");
static bool exclusive_caps[MAX_DEVICES] = { [0 ... (MAX_DEVICES - 1)] = 0 };
module_param_array(exclusive_caps, bool, NULL, 0444);
/* FIXXME: wording */
MODULE_PARM_DESC(exclusive_caps, "whether to announce OUTPUT/CAPTURE capabilities exclusively or not");
/* format specifications */
#define V4L2LOOPBACK_SIZE_MIN_WIDTH 48
#define V4L2LOOPBACK_SIZE_MIN_HEIGHT 32
#define V4L2LOOPBACK_SIZE_MAX_WIDTH 8192
#define V4L2LOOPBACK_SIZE_MAX_HEIGHT 8192
#define V4L2LOOPBACK_SIZE_DEFAULT_WIDTH 640
#define V4L2LOOPBACK_SIZE_DEFAULT_HEIGHT 480
static int max_width = V4L2LOOPBACK_SIZE_MAX_WIDTH;
module_param(max_width, int, S_IRUGO);
MODULE_PARM_DESC(max_width, "maximum frame width");
static int max_height = V4L2LOOPBACK_SIZE_MAX_HEIGHT;
module_param(max_height, int, S_IRUGO);
MODULE_PARM_DESC(max_height, "maximum frame height");
/* control IDs */
#ifndef HAVE__V4L2_CTRLS
# define V4L2LOOPBACK_CID_BASE (V4L2_CID_PRIVATE_BASE)
#else
# define V4L2LOOPBACK_CID_BASE (V4L2_CID_USER_BASE | 0xf000)
#endif
#define CID_KEEP_FORMAT (V4L2LOOPBACK_CID_BASE + 0)
#define CID_SUSTAIN_FRAMERATE (V4L2LOOPBACK_CID_BASE + 1)
#define CID_TIMEOUT (V4L2LOOPBACK_CID_BASE + 2)
#define CID_TIMEOUT_IMAGE_IO (V4L2LOOPBACK_CID_BASE + 3)
static int v4l2loopback_s_ctrl(struct v4l2_ctrl *ctrl);
static const struct v4l2_ctrl_ops v4l2loopback_ctrl_ops = {
.s_ctrl = v4l2loopback_s_ctrl,
};
static const struct v4l2_ctrl_config v4l2loopback_ctrl_keepformat = {
.ops = &v4l2loopback_ctrl_ops,
.id = CID_KEEP_FORMAT,
.name = "keep_format",
.type = V4L2_CTRL_TYPE_BOOLEAN,
.min = 0,
.max = 1,
.step = 1,
.def = 0,
};
static const struct v4l2_ctrl_config v4l2loopback_ctrl_sustainframerate = {
.ops = &v4l2loopback_ctrl_ops,
.id = CID_SUSTAIN_FRAMERATE,
.name = "sustain_framerate",
.type = V4L2_CTRL_TYPE_BOOLEAN,
.min = 0,
.max = 1,
.step = 1,
.def = 0,
};
static const struct v4l2_ctrl_config v4l2loopback_ctrl_timeout = {
.ops = &v4l2loopback_ctrl_ops,
.id = CID_TIMEOUT,
.name = "timeout",
.type = V4L2_CTRL_TYPE_INTEGER,
.min = 0,
.max = MAX_TIMEOUT,
.step = 1,
.def = 0,
};
static const struct v4l2_ctrl_config v4l2loopback_ctrl_timeoutimageio = {
.ops = &v4l2loopback_ctrl_ops,
.id = CID_TIMEOUT_IMAGE_IO,
.name = "timeout_image_io",
.type = V4L2_CTRL_TYPE_BOOLEAN,
.min = 0,
.max = 1,
.step = 1,
.def = 0,
};
/* module structures */
struct v4l2loopback_private {
int devicenr;
};
/* TODO(vasaka) use typenames which are common to kernel, but first find out if
* it is needed */
/* struct keeping state and settings of loopback device */
struct v4l2l_buffer {
struct v4l2_buffer buffer;
struct list_head list_head;
int use_count;
};
struct v4l2_loopback_device {
struct v4l2_device v4l2_dev;
struct v4l2_ctrl_handler ctrl_handler;
struct video_device *vdev;
/* pixel and stream format */
struct v4l2_pix_format pix_format;
struct v4l2_captureparm capture_param;
unsigned long frame_jiffies;
/* ctrls */
int keep_format; /* CID_KEEP_FORMAT; stay ready_for_capture even when all
openers close() the device */
int sustain_framerate; /* CID_SUSTAIN_FRAMERATE; duplicate frames to maintain
(close to) nominal framerate */
/* buffers stuff */
u8 *image; /* pointer to actual buffers data */
unsigned long int imagesize; /* size of buffers data */
int buffers_number; /* should not be big, 4 is a good choice */
struct v4l2l_buffer buffers[MAX_BUFFERS]; /* inner driver buffers */
int used_buffers; /* number of the actually used buffers */
int max_openers; /* how many times can this device be opened */
int write_position; /* number of last written frame + 1 */
struct list_head outbufs_list; /* buffers in output DQBUF order */
int bufpos2index[MAX_BUFFERS]; /* mapping of (read/write_position % used_buffers)
* to inner buffer index */
long buffer_size;
/* sustain_framerate stuff */
struct timer_list sustain_timer;
unsigned int reread_count;
/* timeout stuff */
unsigned long timeout_jiffies; /* CID_TIMEOUT; 0 means disabled */
int timeout_image_io; /* CID_TIMEOUT_IMAGE_IO; next opener will
* read/write to timeout_image */
u8 *timeout_image; /* copy of it will be captured when timeout passes */
struct v4l2l_buffer timeout_image_buffer;
struct timer_list timeout_timer;
int timeout_happened;
/* sync stuff */
atomic_t open_count;
int ready_for_capture;/* set to true when at least one writer opened
* device and negotiated format */
int ready_for_output; /* set to true when no writer is currently attached
* this differs slightly from !ready_for_capture,
* e.g. when using fallback images */
int announce_all_caps;/* set to false, if device caps (OUTPUT/CAPTURE)
* should only be announced if the resp. "ready"
* flag is set; default=TRUE */
wait_queue_head_t read_event;
spinlock_t lock;
};
/* types of opener shows what opener wants to do with loopback */
enum opener_type {
UNNEGOTIATED = 0,
READER = 1,
WRITER = 2,
};
/* struct keeping state and type of opener */
struct v4l2_loopback_opener {
enum opener_type type;
int vidioc_enum_frameintervals_calls;
int read_position; /* number of last processed frame + 1 or
* write_position - 1 if reader went out of sync */
unsigned int reread_count;
struct v4l2_buffer *buffers;
int buffers_number; /* should not be big, 4 is a good choice */
int timeout_image_io;
};
/* this is heavily inspired by the bttv driver found in the linux kernel */
struct v4l2l_format {
char *name;
int fourcc; /* video4linux 2 */
int depth; /* bit/pixel */
int flags;
};
/* set the v4l2l_format.flags to PLANAR for non-packed formats */
#define FORMAT_FLAGS_PLANAR 0x01
#define FORMAT_FLAGS_COMPRESSED 0x02
#ifndef V4L2_PIX_FMT_VP9
#define V4L2_PIX_FMT_VP9 v4l2_fourcc('V', 'P', '9', '0')
#endif
#ifndef V4L2_PIX_FMT_HEVC
#define V4L2_PIX_FMT_HEVC v4l2_fourcc('H', 'E', 'V', 'C')
#endif
static const struct v4l2l_format formats[] = {
#include "v4l2loopback_formats.h"
};
static const unsigned int FORMATS = ARRAY_SIZE(formats);
static char *fourcc2str(unsigned int fourcc, char buf[4])
{
buf[0] = (fourcc >> 0) & 0xFF;
buf[1] = (fourcc >> 8) & 0xFF;
buf[2] = (fourcc >> 16) & 0xFF;
buf[3] = (fourcc >> 24) & 0xFF;
return buf;
}
static const struct v4l2l_format *format_by_fourcc(int fourcc)
{
unsigned int i;
for (i = 0; i < FORMATS; i++) {
if (formats[i].fourcc == fourcc)
return formats + i;
}
dprintk("unsupported format '%c%c%c%c'\n",
(fourcc >> 0) & 0xFF,
(fourcc >> 8) & 0xFF,
(fourcc >> 16) & 0xFF,
(fourcc >> 24) & 0xFF);
return NULL;
}
static void pix_format_set_size(struct v4l2_pix_format *f,
const struct v4l2l_format *fmt,
unsigned int width, unsigned int height)
{
f->width = width;
f->height = height;
if (fmt->flags & FORMAT_FLAGS_PLANAR) {
f->bytesperline = width; /* Y plane */
f->sizeimage = (width * height * fmt->depth) >> 3;
} else if (fmt->flags & FORMAT_FLAGS_COMPRESSED) {
/* doesn't make sense for compressed formats */
f->bytesperline = 0;
f->sizeimage = (width * height * fmt->depth) >> 3;
} else {
f->bytesperline = (width * fmt->depth) >> 3;
f->sizeimage = height * f->bytesperline;
}
}
static int set_timeperframe(struct v4l2_loopback_device *dev,
struct v4l2_fract *tpf)
{
if((tpf->denominator < 1) || (tpf->numerator < 1)) {
return -EINVAL;
}
dev->capture_param.timeperframe = *tpf;
dev->frame_jiffies = max(1UL,
msecs_to_jiffies(1000) * tpf->numerator / tpf->denominator);
return 0;
}
static struct v4l2_loopback_device *v4l2loopback_cd2dev(struct device *cd);
/* device attributes */
/* available via sysfs: /sys/devices/virtual/video4linux/video* */
static ssize_t attr_show_format(struct device *cd,
struct device_attribute *attr, char *buf)
{
/* gets the current format as "FOURCC:WxH@f/s", e.g. "YUYV:320x240@1000/30" */
struct v4l2_loopback_device *dev = v4l2loopback_cd2dev(cd);
const struct v4l2_fract *tpf;
char buf4cc[5], buf_fps[32];
if (!dev || !dev->ready_for_capture)
return 0;
tpf = &dev->capture_param.timeperframe;
fourcc2str(dev->pix_format.pixelformat, buf4cc);
buf4cc[4]=0;
if (tpf->numerator == 1)
snprintf(buf_fps, sizeof(buf_fps), "%d", tpf->denominator);
else
snprintf(buf_fps, sizeof(buf_fps), "%d/%d",
tpf->denominator, tpf->numerator);
return sprintf(buf, "%4s:%dx%d@%s\n",
buf4cc, dev->pix_format.width, dev->pix_format.height, buf_fps);
}
static ssize_t attr_store_format(struct device *cd,
struct device_attribute *attr, const char *buf, size_t len)
{
struct v4l2_loopback_device *dev = v4l2loopback_cd2dev(cd);
int fps_num = 0, fps_den = 1;
/* only fps changing is supported */
if (sscanf(buf, "@%d/%d", &fps_num, &fps_den) > 0) {
struct v4l2_fract f = {
.numerator = fps_den,
.denominator = fps_num
};
int err=0;
if((err=set_timeperframe(dev, &f)) < 0)
return err;
return len;
}
return -EINVAL;
}
static DEVICE_ATTR(format, S_IRUGO | S_IWUSR, attr_show_format, attr_store_format);
static ssize_t attr_show_buffers(struct device *cd,
struct device_attribute *attr, char *buf)
{
struct v4l2_loopback_device *dev = v4l2loopback_cd2dev(cd);
return sprintf(buf, "%d\n", dev->used_buffers);
}
static DEVICE_ATTR(buffers, S_IRUGO, attr_show_buffers, NULL);
static ssize_t attr_show_maxopeners(struct device *cd,
struct device_attribute *attr, char *buf)
{
struct v4l2_loopback_device *dev = v4l2loopback_cd2dev(cd);
return sprintf(buf, "%d\n", dev->max_openers);
}
static ssize_t attr_store_maxopeners(struct device *cd,
struct device_attribute *attr, const char *buf, size_t len)
{
struct v4l2_loopback_device *dev = NULL;
unsigned long curr = 0;
if (kstrtoul(buf, 0, &curr))
return -EINVAL;
dev = v4l2loopback_cd2dev(cd);
if (dev->max_openers == curr)
return len;
if (dev->open_count.counter > curr) {
/* request to limit to less openers as are currently attached to us */
return -EINVAL;
}
dev->max_openers = (int)curr;
return len;
}
static DEVICE_ATTR(max_openers, S_IRUGO | S_IWUSR, attr_show_maxopeners, attr_store_maxopeners);
static void v4l2loopback_remove_sysfs(struct video_device *vdev)
{
#define V4L2_SYSFS_DESTROY(x) device_remove_file(&vdev->dev, &dev_attr_##x)
if (vdev) {
V4L2_SYSFS_DESTROY(format);
V4L2_SYSFS_DESTROY(buffers);
V4L2_SYSFS_DESTROY(max_openers);
/* ... */
}
}
static void v4l2loopback_create_sysfs(struct video_device *vdev)
{
int res = 0;
#define V4L2_SYSFS_CREATE(x) res = device_create_file(&vdev->dev, &dev_attr_##x); if (res < 0) break
if (!vdev)
return;
do {
V4L2_SYSFS_CREATE(format);
V4L2_SYSFS_CREATE(buffers);
V4L2_SYSFS_CREATE(max_openers);
/* ... */
} while (0);
if (res >= 0)
return;
dev_err(&vdev->dev, "%s error: %d\n", __func__, res);
}
/* global module data */
struct v4l2_loopback_device *devs[MAX_DEVICES];
static struct v4l2_loopback_device *v4l2loopback_cd2dev(struct device *cd)
{
struct video_device *loopdev = to_video_device(cd);
struct v4l2loopback_private *ptr =
(struct v4l2loopback_private *)video_get_drvdata(loopdev);
int nr = ptr->devicenr;
if (nr < 0 || nr >= devices) {
printk(KERN_ERR "v4l2-loopback: illegal device %d\n", nr);
return NULL;
}
return devs[nr];
}
static struct v4l2_loopback_device *v4l2loopback_getdevice(struct file *f)
{
struct video_device *loopdev = video_devdata(f);
struct v4l2loopback_private *ptr =
(struct v4l2loopback_private *)video_get_drvdata(loopdev);
int nr = ptr->devicenr;
if (nr < 0 || nr >= devices) {
printk(KERN_ERR "v4l2-loopback: illegal device %d\n", nr);
return NULL;
}
return devs[nr];
}
/* forward declarations */
static void init_buffers(struct v4l2_loopback_device *dev);
static int allocate_buffers(struct v4l2_loopback_device *dev);
static int free_buffers(struct v4l2_loopback_device *dev);
static void try_free_buffers(struct v4l2_loopback_device *dev);
static int allocate_timeout_image(struct v4l2_loopback_device *dev);
static void check_timers(struct v4l2_loopback_device *dev);
static const struct v4l2_file_operations v4l2_loopback_fops;
static const struct v4l2_ioctl_ops v4l2_loopback_ioctl_ops;
/* Queue helpers */
/* next functions sets buffer flags and adjusts counters accordingly */
static inline void set_done(struct v4l2l_buffer *buffer)
{
buffer->buffer.flags &= ~V4L2_BUF_FLAG_QUEUED;
buffer->buffer.flags |= V4L2_BUF_FLAG_DONE;
}
static inline void set_queued(struct v4l2l_buffer *buffer)
{
buffer->buffer.flags &= ~V4L2_BUF_FLAG_DONE;
buffer->buffer.flags |= V4L2_BUF_FLAG_QUEUED;
}
static inline void unset_flags(struct v4l2l_buffer *buffer)
{
buffer->buffer.flags &= ~V4L2_BUF_FLAG_QUEUED;
buffer->buffer.flags &= ~V4L2_BUF_FLAG_DONE;
}
static void vidioc_fill_name(char *buf, int len, int nr)
{
if (card_label[nr] != NULL) {
snprintf(buf, len, card_label[nr]);
} else {
snprintf(buf, len, "Dummy video device (0x%04X)", nr);
}
}
/* V4L2 ioctl caps and params calls */
/* returns device capabilities
* called on VIDIOC_QUERYCAP
*/
static int vidioc_querycap(struct file *file, void *priv, struct v4l2_capability *cap)
{
struct v4l2_loopback_device *dev = v4l2loopback_getdevice(file);
int devnr = ((struct v4l2loopback_private *)video_get_drvdata(dev->vdev))->devicenr;
strlcpy(cap->driver, "v4l2 loopback", sizeof(cap->driver));
vidioc_fill_name(cap->card, sizeof(cap->card), devnr);
snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:v4l2loopback-%03d", devnr);
#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 1, 0)
/* since 3.1.0, the v4l2-core system is supposed to set the version */
cap->version = V4L2LOOPBACK_VERSION_CODE;
#endif
cap->capabilities =
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 19, 0)
V4L2_CAP_DEVICE_CAPS |
#endif
V4L2_CAP_STREAMING | V4L2_CAP_READWRITE;
#ifdef V4L2_CAP_VIDEO_M2M
cap->capabilities |= V4L2_CAP_VIDEO_M2M;
#endif /* V4L2_CAP_VIDEO_M2M */
if (dev->announce_all_caps) {
cap->capabilities |= V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_VIDEO_OUTPUT;
} else {
if (dev->ready_for_capture) {
cap->capabilities |= V4L2_CAP_VIDEO_CAPTURE;
}
if (dev->ready_for_output) {
cap->capabilities |= V4L2_CAP_VIDEO_OUTPUT;
}
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 19, 0)
cap->device_caps = (cap->capabilities & ~V4L2_CAP_DEVICE_CAPS);
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 3, 0)
cap->device_caps = cap->capabilities;
cap->capabilities |= V4L2_CAP_DEVICE_CAPS;
#endif
memset(cap->reserved, 0, sizeof(cap->reserved));
return 0;
}
static int vidioc_enum_framesizes(struct file *file, void *fh, struct v4l2_frmsizeenum *argp)
{
struct v4l2_loopback_device *dev;
/* LATER: what does the index really mean?
* if it's about enumerating formats, we can safely ignore it
* (CHECK)
*/
/* there can be only one... */
if (argp->index)
return -EINVAL;
dev = v4l2loopback_getdevice(file);
if (dev->ready_for_capture) {
/* format has already been negotiated
* cannot change during runtime
*/
argp->type = V4L2_FRMSIZE_TYPE_DISCRETE;
argp->discrete.width = dev->pix_format.width;
argp->discrete.height = dev->pix_format.height;
} else {
/* if the format has not been negotiated yet, we accept anything
*/
argp->type = V4L2_FRMSIZE_TYPE_CONTINUOUS;
argp->stepwise.min_width = V4L2LOOPBACK_SIZE_MIN_WIDTH;
argp->stepwise.min_height = V4L2LOOPBACK_SIZE_MIN_HEIGHT;
argp->stepwise.max_width = max_width;
argp->stepwise.max_height = max_height;
argp->stepwise.step_width = 1;
argp->stepwise.step_height = 1;
}
return 0;
}
/* returns frameinterval (fps) for the set resolution
* called on VIDIOC_ENUM_FRAMEINTERVALS
*/
static int vidioc_enum_frameintervals(struct file *file, void *fh, struct v4l2_frmivalenum *argp)
{
struct v4l2_loopback_device *dev = v4l2loopback_getdevice(file);
struct v4l2_loopback_opener *opener = file->private_data;
if (dev->ready_for_capture) {
if (opener->vidioc_enum_frameintervals_calls > 0)
return -EINVAL;
if (argp->width == dev->pix_format.width &&
argp->height == dev->pix_format.height) {
argp->type = V4L2_FRMIVAL_TYPE_DISCRETE;
argp->discrete = dev->capture_param.timeperframe;
opener->vidioc_enum_frameintervals_calls++;
return 0;
}
return -EINVAL;
}
return 0;
}
/* ------------------ CAPTURE ----------------------- */
/* returns device formats
* called on VIDIOC_ENUM_FMT, with v4l2_buf_type set to V4L2_BUF_TYPE_VIDEO_CAPTURE
*/
static int vidioc_enum_fmt_cap(struct file *file, void *fh, struct v4l2_fmtdesc *f)
{
struct v4l2_loopback_device *dev;
MARK();
dev = v4l2loopback_getdevice(file);
if (f->index)
return -EINVAL;
if (dev->ready_for_capture) {
const __u32 format = dev->pix_format.pixelformat;
snprintf(f->description, sizeof(f->description),
"[%c%c%c%c]",
(format >> 0) & 0xFF,
(format >> 8) & 0xFF,
(format >> 16) & 0xFF,
(format >> 24) & 0xFF);
f->pixelformat = dev->pix_format.pixelformat;
} else {
return -EINVAL;
}
f->flags = 0;
MARK();
return 0;
}
/* returns current video format format fmt
* called on VIDIOC_G_FMT, with v4l2_buf_type set to V4L2_BUF_TYPE_VIDEO_CAPTURE
*/
static int vidioc_g_fmt_cap(struct file *file, void *priv, struct v4l2_format *fmt)
{
struct v4l2_loopback_device *dev;
MARK();
dev = v4l2loopback_getdevice(file);
if (!dev->ready_for_capture)
return -EINVAL;
fmt->fmt.pix = dev->pix_format;
MARK();
return 0;
}
/* checks if it is OK to change to format fmt;
* actual check is done by inner_try_fmt_cap
* just checking that pixelformat is OK and set other parameters, app should
* obey this decision
* called on VIDIOC_TRY_FMT, with v4l2_buf_type set to V4L2_BUF_TYPE_VIDEO_CAPTURE
*/
static int vidioc_try_fmt_cap(struct file *file, void *priv, struct v4l2_format *fmt)
{
struct v4l2_loopback_device *dev;
char buf[5];
dev = v4l2loopback_getdevice(file);
if (0 == dev->ready_for_capture) {
dprintk("setting fmt_cap not possible yet\n");
return -EBUSY;
}
if (fmt->fmt.pix.pixelformat != dev->pix_format.pixelformat)
return -EINVAL;
fmt->fmt.pix = dev->pix_format;
buf[4] = 0;
dprintk("capFOURCC=%s\n", fourcc2str(dev->pix_format.pixelformat, buf));
return 0;
}
/* sets new output format, if possible
* actually format is set by input and we even do not check it, just return
* current one, but it is possible to set subregions of input TODO(vasaka)
* called on VIDIOC_S_FMT, with v4l2_buf_type set to V4L2_BUF_TYPE_VIDEO_CAPTURE
*/
static int vidioc_s_fmt_cap(struct file *file, void *priv, struct v4l2_format *fmt)
{
return vidioc_try_fmt_cap(file, priv, fmt);
}
/* ------------------ OUTPUT ----------------------- */
/* returns device formats;
* LATER: allow all formats
* called on VIDIOC_ENUM_FMT, with v4l2_buf_type set to V4L2_BUF_TYPE_VIDEO_OUTPUT
*/
static int vidioc_enum_fmt_out(struct file *file, void *fh, struct v4l2_fmtdesc *f)
{
struct v4l2_loopback_device *dev;
const struct v4l2l_format *fmt;
dev = v4l2loopback_getdevice(file);
if (dev->ready_for_capture) {
const __u32 format = dev->pix_format.pixelformat;
/* format has been fixed by the writer, so only one single format is supported */
if (f->index)
return -EINVAL;
fmt = format_by_fourcc(format);
if (NULL == fmt)
return -EINVAL;
f->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
/* f->flags = ??; */
snprintf(f->description, sizeof(f->description), "%s", fmt->name);
f->pixelformat = dev->pix_format.pixelformat;
} else {
/* fill in a dummy format */
/* coverity[unsigned_compare] */
if (f->index < 0 || f->index >= FORMATS)
return -EINVAL;
fmt = &formats[f->index];
f->pixelformat = fmt->fourcc;
snprintf(f->description, sizeof(f->description), "%s", fmt->name);
}
f->flags = 0;
return 0;
}
/* returns current video format format fmt */
/* NOTE: this is called from the producer
* so if format has not been negotiated yet,
* it should return ALL of available formats,
* called on VIDIOC_G_FMT, with v4l2_buf_type set to V4L2_BUF_TYPE_VIDEO_OUTPUT
*/
static int vidioc_g_fmt_out(struct file *file, void *priv, struct v4l2_format *fmt)
{
struct v4l2_loopback_device *dev;
MARK();
dev = v4l2loopback_getdevice(file);
/*
* LATER: this should return the currently valid format
* gstreamer doesn't like it, if this returns -EINVAL, as it
* then concludes that there is _no_ valid format
* CHECK whether this assumption is wrong,
* or whether we have to always provide a valid format
*/
fmt->fmt.pix = dev->pix_format;
return 0;
}
/* checks if it is OK to change to format fmt;
* if format is negotiated do not change it
* called on VIDIOC_TRY_FMT with v4l2_buf_type set to V4L2_BUF_TYPE_VIDEO_OUTPUT
*/
static int vidioc_try_fmt_out(struct file *file, void *priv, struct v4l2_format *fmt)
{
struct v4l2_loopback_device *dev;
MARK();
dev = v4l2loopback_getdevice(file);
/* TODO(vasaka) loopback does not care about formats writer want to set,
* maybe it is a good idea to restrict format somehow */
if (dev->ready_for_capture) {
fmt->fmt.pix = dev->pix_format;
} else {
__u32 w = fmt->fmt.pix.width;
__u32 h = fmt->fmt.pix.height;
__u32 pixfmt = fmt->fmt.pix.pixelformat;
const struct v4l2l_format *format = format_by_fourcc(pixfmt);
if (w > max_width)
w = max_width;
if (h > max_height)
h = max_height;
dprintk("trying image %dx%d\n", w, h);
if (w < 1)
w = V4L2LOOPBACK_SIZE_DEFAULT_WIDTH;
if (h < 1)
h = V4L2LOOPBACK_SIZE_DEFAULT_HEIGHT;
if (NULL == format)
format = &formats[0];
pix_format_set_size(&fmt->fmt.pix, format, w, h);
fmt->fmt.pix.pixelformat = format->fourcc;
fmt->fmt.pix.colorspace = V4L2_COLORSPACE_SRGB;
if (V4L2_FIELD_ANY == fmt->fmt.pix.field)
fmt->fmt.pix.field = V4L2_FIELD_NONE;
/* FIXXME: try_fmt should never modify the device-state */
dev->pix_format = fmt->fmt.pix;
}
return 0;
}
/* sets new output format, if possible;
* allocate data here because we do not know if it will be streaming or
* read/write IO
* called on VIDIOC_S_FMT with v4l2_buf_type set to V4L2_BUF_TYPE_VIDEO_OUTPUT
*/
static int vidioc_s_fmt_out(struct file *file, void *priv, struct v4l2_format *fmt)
{
struct v4l2_loopback_device *dev;
char buf[5];
int ret;
MARK();
dev = v4l2loopback_getdevice(file);