/* * 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 }; /* * Active devices */ static struct video_device *video_device[VIDEO_NUM_DEVICES]; static DEFINE_MUTEX(videodev_lock); static DECLARE_BITMAP(video_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES); 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); /* Called when the last user of the character device is gone. */ static void v4l2_chardev_release(struct kobject *kobj) { struct video_device *vfd = container_of(kobj, struct video_device, cdev.kobj); mutex_lock(&videodev_lock); if (video_device[vfd->minor] != vfd) { mutex_unlock(&videodev_lock); BUG(); return; } /* Free up this device for reuse */ video_device[vfd->minor] = NULL; clear_bit(vfd->num, video_nums[vfd->vfl_type]); mutex_unlock(&videodev_lock); /* Release the character device */ vfd->cdev_release(kobj); /* Release video_device and perform other cleanups as needed. */ if (vfd->release) vfd->release(vfd); } /* The new kobj_type for the character device */ static struct kobj_type v4l2_ktype_cdev_default = { .release = v4l2_chardev_release, }; static void video_release(struct device *cd) { struct video_device *vfd = container_of(cd, struct video_device, dev); /* It's now safe to delete the char device. This will either trigger the v4l2_chardev_release immediately (if the refcount goes to 0) or later when the last user of the character device closes it. */ cdev_del(&vfd->cdev); } static struct class video_class = { .name = VIDEO_NAME, .dev_attrs = video_device_attrs, .dev_release = video_release, }; struct video_device *video_devdata(struct file *file) { return video_device[iminor(file->f_path.dentry->d_inode)]; } EXPORT_SYMBOL(video_devdata); /** * 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; } /* Some drivers do not set the parent. In that case always return 0. */ if (vdev->parent == NULL) return 0; 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 ret; int minor_offset = 0; int minor_cnt = VIDEO_NUM_DEVICES; const 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: name_base = "video"; break; case VFL_TYPE_VTX: name_base = "vtx"; break; case VFL_TYPE_VBI: name_base = "vbi"; break; case VFL_TYPE_RADIO: name_base = "radio"; break; default: printk(KERN_ERR "%s called with unknown type: %d\n", __func__, type); return -EINVAL; } vfd->vfl_type = type; #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES /* Keep the ranges for the first four types for historical * reasons. * Newer devices (not yet in place) should use the range * of 128-191 and just pick the first free minor there * (new style). */ switch (type) { case VFL_TYPE_GRABBER: minor_offset = 0; minor_cnt = 64; break; case VFL_TYPE_RADIO: minor_offset = 64; minor_cnt = 64; break; case VFL_TYPE_VTX: minor_offset = 192; minor_cnt = 32; break; case VFL_TYPE_VBI: minor_offset = 224; minor_cnt = 32; break; default: minor_offset = 128; minor_cnt = 64; break; } #endif /* Initialize the character device */ cdev_init(&vfd->cdev, vfd->fops); vfd->cdev.owner = vfd->fops->owner; /* pick a minor number */ mutex_lock(&videodev_lock); nr = find_next_zero_bit(video_nums[type], minor_cnt, nr == -1 ? 0 : nr); if (nr == minor_cnt) nr = find_first_zero_bit(video_nums[type], minor_cnt); if (nr == minor_cnt) { printk(KERN_ERR "could not get a free kernel number\n"); mutex_unlock(&videodev_lock); return -ENFILE; } #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES /* 1-on-1 mapping of kernel number to minor number */ i = nr; #else /* The kernel number and minor numbers are independent */ for (i = 0; i < VIDEO_NUM_DEVICES; i++) if (video_device[i] == NULL) break; if (i == VIDEO_NUM_DEVICES) { mutex_unlock(&videodev_lock); printk(KERN_ERR "could not get a free minor\n"); return -ENFILE; } #endif vfd->minor = i + minor_offset; vfd->num = nr; set_bit(nr, video_nums[type]); BUG_ON(video_device[vfd->minor]); video_device[vfd->minor] = vfd; 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; } ret = cdev_add(&vfd->cdev, MKDEV(VIDEO_MAJOR, vfd->minor), 1); if (ret < 0) { printk(KERN_ERR "%s: cdev_add 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; dev_set_name(&vfd->dev, "%s%d", name_base, nr); ret = device_register(&vfd->dev); if (ret < 0) { printk(KERN_ERR "%s: device_register failed\n", __func__); goto del_cdev; } /* Remember the cdev's release function */ vfd->cdev_release = vfd->cdev.kobj.ktype->release; /* Install our own */ vfd->cdev.kobj.ktype = &v4l2_ktype_cdev_default; return 0; del_cdev: cdev_del(&vfd->cdev); fail_minor: mutex_lock(&videodev_lock); video_device[vfd->minor] = NULL; clear_bit(vfd->num, video_nums[type]); 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) { device_unregister(&vfd->dev); } EXPORT_SYMBOL(video_unregister_device); /* * Initialise video for linux */ static int __init videodev_init(void) { dev_t dev = MKDEV(VIDEO_MAJOR, 0); int ret; printk(KERN_INFO "Linux video capture interface: v2.00\n"); ret = register_chrdev_region(dev, VIDEO_NUM_DEVICES, VIDEO_NAME); if (ret < 0) { printk(KERN_WARNING "videodev: unable to get major %d\n", VIDEO_MAJOR); return ret; } ret = class_register(&video_class); if (ret < 0) { unregister_chrdev_region(dev, VIDEO_NUM_DEVICES); printk(KERN_WARNING "video_dev: class_register failed\n"); return -EIO; } return 0; } static void __exit videodev_exit(void) { dev_t dev = MKDEV(VIDEO_MAJOR, 0); class_unregister(&video_class); unregister_chrdev_region(dev, VIDEO_NUM_DEVICES); } 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: */