/* * 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, (version 1) * Mauro Carvalho Chehab (version 2) * * Fixes: 20000516 Claudio Matsuoka * - Added procfs support */ #include #include #include #include #include #include #include #include #include #include #include #include #include #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) { return kzalloc(sizeof(struct video_device), GFP_KERNEL); } EXPORT_SYMBOL(video_device_alloc); void video_device_release(struct video_device *vfd) { kfree(vfd); } EXPORT_SYMBOL(video_device_release); void video_device_release_empty(struct video_device *vfd) { /* Do nothing */ /* Only valid when the video_device struct is a static. */ } EXPORT_SYMBOL(video_device_release_empty); static void video_release(struct device *cd) { struct video_device *vfd = container_of(cd, struct video_device, dev); 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; 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); 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); return err; } /** * 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_index - 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) * @index: stream number based on parent device; * -1 if auto assign, requested number otherwise * * 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; void *priv = video_get_drvdata(vfd); /* the release callback MUST be present */ BUG_ON(!vfd->release); if (vfd == NULL) return -EINVAL; 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 -EINVAL; } /* 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; } /* sysfs class */ memset(&vfd->dev, 0, sizeof(vfd->dev)); /* The memset above cleared the device's drvdata, so put back the copy we made earlier. */ video_set_drvdata(vfd, priv); 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; } return 0; fail_minor: mutex_lock(&videodev_lock); video_device[vfd->minor] = NULL; mutex_unlock(&videodev_lock); vfd->minor = -1; 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 "); MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2"); MODULE_LICENSE("GPL"); /* * Local variables: * c-basic-offset: 8 * End: */