From 0ce8f2390b5280887a2ac179faf2aa01604cb1cc Mon Sep 17 00:00:00 2001 From: Paul Elder Date: Fri, 6 Dec 2019 04:14:52 -0500 Subject: v4l2: v4l2_compat: Add V4L2 compatibility layer Add libcamera V4L2 compatibility layer. This initial implementation supports the minimal set of V4L2 operations, which allows getting, setting, and enumerating formats, and streaming frames from a video device. Some data about the wrapped V4L2 video device are hardcoded. Add a build option named 'v4l2' and adjust the build system to selectively compile the V4L2 compatibility layer. For now we match the V4L2 device node to a libcamera camera based on a devnum that a pipeline handler may optionally map to a libcamera camera. Signed-off-by: Paul Elder Reviewed-by: Jacopo Mondi Reviewed-by: Laurent Pinchart --- src/v4l2/v4l2_compat.cpp | 85 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 src/v4l2/v4l2_compat.cpp (limited to 'src/v4l2/v4l2_compat.cpp') diff --git a/src/v4l2/v4l2_compat.cpp b/src/v4l2/v4l2_compat.cpp new file mode 100644 index 00000000..171ebed6 --- /dev/null +++ b/src/v4l2/v4l2_compat.cpp @@ -0,0 +1,85 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * v4l2_compat.cpp - V4L2 compatibility layer + */ + +#include "v4l2_compat_manager.h" + +#include +#include +#include +#include +#include +#include + +#define LIBCAMERA_PUBLIC __attribute__((visibility("default"))) + +using namespace libcamera; + +#define extract_va_arg(type, arg, last) \ +{ \ + va_list ap; \ + va_start(ap, last); \ + arg = va_arg(ap, type); \ + va_end(ap); \ +} + +extern "C" { + +LIBCAMERA_PUBLIC int open(const char *path, int oflag, ...) +{ + mode_t mode = 0; + if (oflag & O_CREAT || oflag & O_TMPFILE) + extract_va_arg(mode_t, mode, oflag); + + return V4L2CompatManager::instance()->openat(AT_FDCWD, path, + oflag, mode); +} + +/* _FORTIFY_SOURCE redirects open to __open_2 */ +LIBCAMERA_PUBLIC extern __typeof(open) __open_2 __attribute__ ((alias("open"))); + +LIBCAMERA_PUBLIC int openat(int dirfd, const char *path, int oflag, ...) +{ + mode_t mode = 0; + if (oflag & O_CREAT || oflag & O_TMPFILE) + extract_va_arg(mode_t, mode, oflag); + + return V4L2CompatManager::instance()->openat(dirfd, path, oflag, mode); +} + +LIBCAMERA_PUBLIC extern __typeof(openat) __openat_2 __attribute__ ((alias("openat"))); + +LIBCAMERA_PUBLIC int dup(int oldfd) +{ + return V4L2CompatManager::instance()->dup(oldfd); +} + +LIBCAMERA_PUBLIC int close(int fd) +{ + return V4L2CompatManager::instance()->close(fd); +} + +LIBCAMERA_PUBLIC void *mmap(void *addr, size_t length, int prot, int flags, + int fd, off_t offset) +{ + return V4L2CompatManager::instance()->mmap(addr, length, prot, flags, + fd, offset); +} + +LIBCAMERA_PUBLIC int munmap(void *addr, size_t length) +{ + return V4L2CompatManager::instance()->munmap(addr, length); +} + +LIBCAMERA_PUBLIC int ioctl(int fd, unsigned long request, ...) +{ + void *arg; + extract_va_arg(void *, arg, request); + + return V4L2CompatManager::instance()->ioctl(fd, request, arg); +} + +} -- cgit v1.2.1