diff options
Diffstat (limited to 'drivers/media/video/v4l2-dev.c')
| -rw-r--r-- | drivers/media/video/v4l2-dev.c | 422 |
1 files changed, 422 insertions, 0 deletions
diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c new file mode 100644 index 000000000000..556615fe93de --- /dev/null +++ b/drivers/media/video/v4l2-dev.c @@ -0,0 +1,422 @@ +/* + * Video capture interface for Linux version 2 + * + * A generic video device interface for the LINUX operating system + * using a set of device structures/vectors for low level operations. + * + * 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. + * + * Authors: Alan Cox, <alan@redhat.com> (version 1) + * Mauro Carvalho Chehab <mchehab@infradead.org> (version 2) + * + * Fixes: 20000516 Claudio Matsuoka <claudio@conectiva.com> + * - Added procfs support + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/kmod.h> +#include <linux/slab.h> +#include <linux/smp_lock.h> +#include <asm/uaccess.h> +#include <asm/system.h> + +#include <media/v4l2-common.h> + +#define VIDEO_NUM_DEVICES 256 +#define VIDEO_NAME "video4linux" + +/* + * sysfs stuff + */ + +static ssize_t show_index(struct device *cd, + struct device_attribute *attr, char *buf) +{ + struct video_device *vfd = container_of(cd, struct video_device, dev); + return sprintf(buf, "%i\n", vfd->index); +} + +static ssize_t show_name(struct device *cd, + struct device_attribute *attr, char *buf) +{ + struct video_device *vfd = container_of(cd, struct video_device, dev); + return sprintf(buf, "%.*s\n", (int)sizeof(vfd->name), vfd->name); +} + +static struct device_attribute video_device_attrs[] = { + __ATTR(name, S_IRUGO, show_name, NULL), + __ATTR(index, S_IRUGO, show_index, NULL), + __ATTR_NULL +}; + +struct video_device *video_device_alloc(void) +{ + struct video_device *vfd; + + vfd = kzalloc(sizeof(*vfd), GFP_KERNEL); + return vfd; +} +EXPORT_SYMBOL(video_device_alloc); + +void video_device_release(struct video_device *vfd) +{ + kfree(vfd); +} +EXPORT_SYMBOL(video_device_release); + +static void video_release(struct device *cd) +{ + struct video_device *vfd = container_of(cd, struct video_device, dev); + +#if 1 + /* needed until all drivers are fixed */ + if (!vfd->release) + return; +#endif + vfd->release(vfd); +} + +static struct class video_class = { + .name = VIDEO_NAME, + .dev_attrs = video_device_attrs, + .dev_release = video_release, +}; + +/* + * Active devices + */ + +static struct video_device *video_device[VIDEO_NUM_DEVICES]; +static DEFINE_MUTEX(videodev_lock); + +struct video_device *video_devdata(struct file *file) +{ + return video_device[iminor(file->f_path.dentry->d_inode)]; +} +EXPORT_SYMBOL(video_devdata); + +/* + * Open a video device - FIXME: Obsoleted + */ +static int video_open(struct inode *inode, struct file *file) +{ + unsigned int minor = iminor(inode); + int err = 0; + struct video_device *vfl; + const struct file_operations *old_fops; + + if (minor >= VIDEO_NUM_DEVICES) + return -ENODEV; + lock_kernel(); + mutex_lock(&videodev_lock); + vfl = video_device[minor]; + if (vfl == NULL) { + mutex_unlock(&videodev_lock); + request_module("char-major-%d-%d", VIDEO_MAJOR, minor); + mutex_lock(&videodev_lock); + vfl = video_device[minor]; + if (vfl == NULL) { + mutex_unlock(&videodev_lock); + unlock_kernel(); + return -ENODEV; + } + } + old_fops = file->f_op; + file->f_op = fops_get(vfl->fops); + if (file->f_op->open) + err = file->f_op->open(inode, file); + if (err) { + fops_put(file->f_op); + file->f_op = fops_get(old_fops); + } + fops_put(old_fops); + mutex_unlock(&videodev_lock); + unlock_kernel(); + return err; +} + +/* + * open/release helper functions -- handle exclusive opens + * Should be removed soon + */ +int video_exclusive_open(struct inode *inode, struct file *file) +{ + struct video_device *vfl = video_devdata(file); + int retval = 0; + + mutex_lock(&vfl->lock); + if (vfl->users) + retval = -EBUSY; + else + vfl->users++; + mutex_unlock(&vfl->lock); + return retval; +} +EXPORT_SYMBOL(video_exclusive_open); + +int video_exclusive_release(struct inode *inode, struct file *file) +{ + struct video_device *vfl = video_devdata(file); + + vfl->users--; + return 0; +} +EXPORT_SYMBOL(video_exclusive_release); + +/** + * get_index - assign stream number based on parent device + * @vdev: video_device to assign index number to, vdev->dev should be assigned + * @num: -1 if auto assign, requested number otherwise + * + * + * returns -ENFILE if num is already in use, a free index number if + * successful. + */ +static int get_index(struct video_device *vdev, int num) +{ + u32 used = 0; + const int max_index = sizeof(used) * 8 - 1; + int i; + + /* Currently a single v4l driver instance cannot create more than + 32 devices. + Increase to u64 or an array of u32 if more are needed. */ + if (num > max_index) { + printk(KERN_ERR "videodev: %s num is too large\n", __func__); + return -EINVAL; + } + + for (i = 0; i < VIDEO_NUM_DEVICES; i++) { + if (video_device[i] != NULL && + video_device[i] != vdev && + video_device[i]->parent == vdev->parent) { + used |= 1 << video_device[i]->index; + } + } + + if (num >= 0) { + if (used & (1 << num)) + return -ENFILE; + return num; + } + + i = ffz(used); + return i > max_index ? -ENFILE : i; +} + +static const struct file_operations video_fops; + +int video_register_device(struct video_device *vfd, int type, int nr) +{ + return video_register_device_index(vfd, type, nr, -1); +} +EXPORT_SYMBOL(video_register_device); + +/** + * video_register_device - register video4linux devices + * @vfd: video device structure we want to register + * @type: type of device to register + * @nr: which device number (0 == /dev/video0, 1 == /dev/video1, ... + * -1 == first free) + * + * The registration code assigns minor numbers based on the type + * requested. -ENFILE is returned in all the device slots for this + * category are full. If not then the minor field is set and the + * driver initialize function is called (if non %NULL). + * + * Zero is returned on success. + * + * Valid types are + * + * %VFL_TYPE_GRABBER - A frame grabber + * + * %VFL_TYPE_VTX - A teletext device + * + * %VFL_TYPE_VBI - Vertical blank data (undecoded) + * + * %VFL_TYPE_RADIO - A radio card + */ + +int video_register_device_index(struct video_device *vfd, int type, int nr, + int index) +{ + int i = 0; + int base; + int end; + int ret; + char *name_base; + + switch (type) { + case VFL_TYPE_GRABBER: + base = MINOR_VFL_TYPE_GRABBER_MIN; + end = MINOR_VFL_TYPE_GRABBER_MAX+1; + name_base = "video"; + break; + case VFL_TYPE_VTX: + base = MINOR_VFL_TYPE_VTX_MIN; + end = MINOR_VFL_TYPE_VTX_MAX+1; + name_base = "vtx"; + break; + case VFL_TYPE_VBI: + base = MINOR_VFL_TYPE_VBI_MIN; + end = MINOR_VFL_TYPE_VBI_MAX+1; + name_base = "vbi"; + break; + case VFL_TYPE_RADIO: + base = MINOR_VFL_TYPE_RADIO_MIN; + end = MINOR_VFL_TYPE_RADIO_MAX+1; + name_base = "radio"; + break; + default: + printk(KERN_ERR "%s called with unknown type: %d\n", + __func__, type); + return -1; + } + + /* pick a minor number */ + mutex_lock(&videodev_lock); + if (nr >= 0 && nr < end-base) { + /* use the one the driver asked for */ + i = base + nr; + if (NULL != video_device[i]) { + mutex_unlock(&videodev_lock); + return -ENFILE; + } + } else { + /* use first free */ + for (i = base; i < end; i++) + if (NULL == video_device[i]) + break; + if (i == end) { + mutex_unlock(&videodev_lock); + return -ENFILE; + } + } + video_device[i] = vfd; + vfd->vfl_type = type; + vfd->minor = i; + + ret = get_index(vfd, index); + vfd->index = ret; + + mutex_unlock(&videodev_lock); + + if (ret < 0) { + printk(KERN_ERR "%s: get_index failed\n", __func__); + goto fail_minor; + } + + mutex_init(&vfd->lock); + + /* sysfs class */ + memset(&vfd->dev, 0x00, sizeof(vfd->dev)); + vfd->dev.class = &video_class; + vfd->dev.devt = MKDEV(VIDEO_MAJOR, vfd->minor); + if (vfd->parent) + vfd->dev.parent = vfd->parent; + sprintf(vfd->dev.bus_id, "%s%d", name_base, i - base); + ret = device_register(&vfd->dev); + if (ret < 0) { + printk(KERN_ERR "%s: device_register failed\n", __func__); + goto fail_minor; + } + +#if 1 + /* needed until all drivers are fixed */ + if (!vfd->release) + printk(KERN_WARNING "videodev: \"%s\" has no release callback. " + "Please fix your driver for proper sysfs support, see " + "http://lwn.net/Articles/36850/\n", vfd->name); +#endif + return 0; + +fail_minor: + mutex_lock(&videodev_lock); + video_device[vfd->minor] = NULL; + vfd->minor = -1; + mutex_unlock(&videodev_lock); + return ret; +} +EXPORT_SYMBOL(video_register_device_index); + +/** + * video_unregister_device - unregister a video4linux device + * @vfd: the device to unregister + * + * This unregisters the passed device and deassigns the minor + * number. Future open calls will be met with errors. + */ + +void video_unregister_device(struct video_device *vfd) +{ + mutex_lock(&videodev_lock); + if (video_device[vfd->minor] != vfd) + panic("videodev: bad unregister"); + + video_device[vfd->minor] = NULL; + device_unregister(&vfd->dev); + mutex_unlock(&videodev_lock); +} +EXPORT_SYMBOL(video_unregister_device); + +/* + * Video fs operations + */ +static const struct file_operations video_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .open = video_open, +}; + +/* + * Initialise video for linux + */ + +static int __init videodev_init(void) +{ + int ret; + + printk(KERN_INFO "Linux video capture interface: v2.00\n"); + if (register_chrdev(VIDEO_MAJOR, VIDEO_NAME, &video_fops)) { + printk(KERN_WARNING "video_dev: unable to get major %d\n", VIDEO_MAJOR); + return -EIO; + } + + ret = class_register(&video_class); + if (ret < 0) { + unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME); + printk(KERN_WARNING "video_dev: class_register failed\n"); + return -EIO; + } + + return 0; +} + +static void __exit videodev_exit(void) +{ + class_unregister(&video_class); + unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME); +} + +module_init(videodev_init) +module_exit(videodev_exit) + +MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>"); +MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2"); +MODULE_LICENSE("GPL"); + + +/* + * Local variables: + * c-basic-offset: 8 + * End: + */ |
