linux/drivers/media/video/v4l2-dev.c
Alexey Dobriyan 405f55712d headers: smp_lock.h redux
* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
  It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

  This will make hardirq.h inclusion cheaper for every PREEMPT=n config
  (which includes allmodconfig/allyesconfig, BTW)

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-12 12:22:34 -07:00

616 lines
15 KiB
C

/*
* 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@lxorguk.ukuu.org.uk> (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 <asm/uaccess.h>
#include <asm/system.h>
#include <media/v4l2-common.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ioctl.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 *vdev = to_video_device(cd);
return sprintf(buf, "%i\n", vdev->index);
}
static ssize_t show_name(struct device *cd,
struct device_attribute *attr, char *buf)
{
struct video_device *vdev = to_video_device(cd);
return sprintf(buf, "%.*s\n", (int)sizeof(vdev->name), vdev->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 *vdev)
{
kfree(vdev);
}
EXPORT_SYMBOL(video_device_release);
void video_device_release_empty(struct video_device *vdev)
{
/* Do nothing */
/* Only valid when the video_device struct is a static. */
}
EXPORT_SYMBOL(video_device_release_empty);
static inline void video_get(struct video_device *vdev)
{
get_device(&vdev->dev);
}
static inline void video_put(struct video_device *vdev)
{
put_device(&vdev->dev);
}
/* Called when the last user of the video device exits. */
static void v4l2_device_release(struct device *cd)
{
struct video_device *vdev = to_video_device(cd);
mutex_lock(&videodev_lock);
if (video_device[vdev->minor] != vdev) {
mutex_unlock(&videodev_lock);
/* should not happen */
WARN_ON(1);
return;
}
/* Free up this device for reuse */
video_device[vdev->minor] = NULL;
/* Delete the cdev on this minor as well */
cdev_del(vdev->cdev);
/* Just in case some driver tries to access this from
the release() callback. */
vdev->cdev = NULL;
/* Mark minor as free */
clear_bit(vdev->num, video_nums[vdev->vfl_type]);
mutex_unlock(&videodev_lock);
/* Release video_device and perform other
cleanups as needed. */
vdev->release(vdev);
}
static struct class video_class = {
.name = VIDEO_NAME,
.dev_attrs = video_device_attrs,
};
struct video_device *video_devdata(struct file *file)
{
return video_device[iminor(file->f_path.dentry->d_inode)];
}
EXPORT_SYMBOL(video_devdata);
static ssize_t v4l2_read(struct file *filp, char __user *buf,
size_t sz, loff_t *off)
{
struct video_device *vdev = video_devdata(filp);
if (!vdev->fops->read)
return -EINVAL;
if (video_is_unregistered(vdev))
return -EIO;
return vdev->fops->read(filp, buf, sz, off);
}
static ssize_t v4l2_write(struct file *filp, const char __user *buf,
size_t sz, loff_t *off)
{
struct video_device *vdev = video_devdata(filp);
if (!vdev->fops->write)
return -EINVAL;
if (video_is_unregistered(vdev))
return -EIO;
return vdev->fops->write(filp, buf, sz, off);
}
static unsigned int v4l2_poll(struct file *filp, struct poll_table_struct *poll)
{
struct video_device *vdev = video_devdata(filp);
if (!vdev->fops->poll || video_is_unregistered(vdev))
return DEFAULT_POLLMASK;
return vdev->fops->poll(filp, poll);
}
static int v4l2_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
struct video_device *vdev = video_devdata(filp);
if (!vdev->fops->ioctl)
return -ENOTTY;
/* Allow ioctl to continue even if the device was unregistered.
Things like dequeueing buffers might still be useful. */
return vdev->fops->ioctl(filp, cmd, arg);
}
static long v4l2_unlocked_ioctl(struct file *filp,
unsigned int cmd, unsigned long arg)
{
struct video_device *vdev = video_devdata(filp);
if (!vdev->fops->unlocked_ioctl)
return -ENOTTY;
/* Allow ioctl to continue even if the device was unregistered.
Things like dequeueing buffers might still be useful. */
return vdev->fops->unlocked_ioctl(filp, cmd, arg);
}
#ifdef CONFIG_MMU
#define v4l2_get_unmapped_area NULL
#else
static unsigned long v4l2_get_unmapped_area(struct file *filp,
unsigned long addr, unsigned long len, unsigned long pgoff,
unsigned long flags)
{
struct video_device *vdev = video_devdata(filp);
if (!vdev->fops->get_unmapped_area)
return -ENOSYS;
if (video_is_unregistered(vdev))
return -ENODEV;
return vdev->fops->get_unmapped_area(filp, addr, len, pgoff, flags);
}
#endif
static int v4l2_mmap(struct file *filp, struct vm_area_struct *vm)
{
struct video_device *vdev = video_devdata(filp);
if (!vdev->fops->mmap ||
video_is_unregistered(vdev))
return -ENODEV;
return vdev->fops->mmap(filp, vm);
}
/* Override for the open function */
static int v4l2_open(struct inode *inode, struct file *filp)
{
struct video_device *vdev;
int ret = 0;
/* Check if the video device is available */
mutex_lock(&videodev_lock);
vdev = video_devdata(filp);
/* return ENODEV if the video device has been removed
already or if it is not registered anymore. */
if (vdev == NULL || video_is_unregistered(vdev)) {
mutex_unlock(&videodev_lock);
return -ENODEV;
}
/* and increase the device refcount */
video_get(vdev);
mutex_unlock(&videodev_lock);
if (vdev->fops->open)
ret = vdev->fops->open(filp);
/* decrease the refcount in case of an error */
if (ret)
video_put(vdev);
return ret;
}
/* Override for the release function */
static int v4l2_release(struct inode *inode, struct file *filp)
{
struct video_device *vdev = video_devdata(filp);
int ret = 0;
if (vdev->fops->release)
vdev->fops->release(filp);
/* decrease the refcount unconditionally since the release()
return value is ignored. */
video_put(vdev);
return ret;
}
static const struct file_operations v4l2_unlocked_fops = {
.owner = THIS_MODULE,
.read = v4l2_read,
.write = v4l2_write,
.open = v4l2_open,
.get_unmapped_area = v4l2_get_unmapped_area,
.mmap = v4l2_mmap,
.unlocked_ioctl = v4l2_unlocked_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = v4l2_compat_ioctl32,
#endif
.release = v4l2_release,
.poll = v4l2_poll,
.llseek = no_llseek,
};
static const struct file_operations v4l2_fops = {
.owner = THIS_MODULE,
.read = v4l2_read,
.write = v4l2_write,
.open = v4l2_open,
.get_unmapped_area = v4l2_get_unmapped_area,
.mmap = v4l2_mmap,
.ioctl = v4l2_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = v4l2_compat_ioctl32,
#endif
.release = v4l2_release,
.poll = v4l2_poll,
.llseek = no_llseek,
};
/**
* get_index - assign stream number based on parent device
* @vdev: video_device to assign index number to, vdev->parent should be assigned
* @num: -1 if auto assign, requested number otherwise
*
* Note that when this is called the new device has not yet been registered
* in the video_device array.
*
* Returns -ENFILE if num is already in use, a free index number if
* successful.
*/
static int get_index(struct video_device *vdev, int num)
{
/* This can be static since this function is called with the global
videodev_lock held. */
static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES);
int i;
if (num >= VIDEO_NUM_DEVICES) {
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
num or 0. */
if (vdev->parent == NULL)
return num >= 0 ? num : 0;
bitmap_zero(used, VIDEO_NUM_DEVICES);
for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
if (video_device[i] != NULL &&
video_device[i]->parent == vdev->parent) {
set_bit(video_device[i]->index, used);
}
}
if (num >= 0) {
if (test_bit(num, used))
return -ENFILE;
return num;
}
i = find_first_zero_bit(used, VIDEO_NUM_DEVICES);
return i == VIDEO_NUM_DEVICES ? -ENFILE : i;
}
int video_register_device(struct video_device *vdev, int type, int nr)
{
return video_register_device_index(vdev, type, nr, -1);
}
EXPORT_SYMBOL(video_register_device);
/**
* video_register_device_index - register video4linux devices
* @vdev: 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 *vdev, 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(vdev);
/* A minor value of -1 marks this video device as never
having been registered */
vdev->minor = -1;
/* the release callback MUST be present */
WARN_ON(!vdev->release);
if (!vdev->release)
return -EINVAL;
/* Part 1: check device type */
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;
}
vdev->vfl_type = type;
vdev->cdev = NULL;
if (vdev->v4l2_dev && vdev->v4l2_dev->dev)
vdev->parent = vdev->v4l2_dev->dev;
/* Part 2: find a free minor, kernel number and device index. */
#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
/* 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
vdev->minor = i + minor_offset;
vdev->num = nr;
set_bit(nr, video_nums[type]);
/* Should not happen since we thought this minor was free */
WARN_ON(video_device[vdev->minor] != NULL);
ret = vdev->index = get_index(vdev, index);
mutex_unlock(&videodev_lock);
if (ret < 0) {
printk(KERN_ERR "%s: get_index failed\n", __func__);
goto cleanup;
}
/* Part 3: Initialize the character device */
vdev->cdev = cdev_alloc();
if (vdev->cdev == NULL) {
ret = -ENOMEM;
goto cleanup;
}
if (vdev->fops->unlocked_ioctl)
vdev->cdev->ops = &v4l2_unlocked_fops;
else
vdev->cdev->ops = &v4l2_fops;
vdev->cdev->owner = vdev->fops->owner;
ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
if (ret < 0) {
printk(KERN_ERR "%s: cdev_add failed\n", __func__);
kfree(vdev->cdev);
vdev->cdev = NULL;
goto cleanup;
}
/* Part 4: register the device with sysfs */
memset(&vdev->dev, 0, sizeof(vdev->dev));
/* The memset above cleared the device's drvdata, so
put back the copy we made earlier. */
video_set_drvdata(vdev, priv);
vdev->dev.class = &video_class;
vdev->dev.devt = MKDEV(VIDEO_MAJOR, vdev->minor);
if (vdev->parent)
vdev->dev.parent = vdev->parent;
dev_set_name(&vdev->dev, "%s%d", name_base, nr);
ret = device_register(&vdev->dev);
if (ret < 0) {
printk(KERN_ERR "%s: device_register failed\n", __func__);
goto cleanup;
}
/* Register the release callback that will be called when the last
reference to the device goes away. */
vdev->dev.release = v4l2_device_release;
/* Part 5: Activate this minor. The char device can now be used. */
mutex_lock(&videodev_lock);
video_device[vdev->minor] = vdev;
mutex_unlock(&videodev_lock);
return 0;
cleanup:
mutex_lock(&videodev_lock);
if (vdev->cdev)
cdev_del(vdev->cdev);
clear_bit(vdev->num, video_nums[type]);
mutex_unlock(&videodev_lock);
/* Mark this video device as never having been registered. */
vdev->minor = -1;
return ret;
}
EXPORT_SYMBOL(video_register_device_index);
/**
* video_unregister_device - unregister a video4linux device
* @vdev: the device to unregister
*
* This unregisters the passed device. Future open calls will
* be met with errors.
*/
void video_unregister_device(struct video_device *vdev)
{
/* Check if vdev was ever registered at all */
if (!vdev || vdev->minor < 0)
return;
mutex_lock(&videodev_lock);
set_bit(V4L2_FL_UNREGISTERED, &vdev->flags);
mutex_unlock(&videodev_lock);
device_unregister(&vdev->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 <mchehab@infradead.org>");
MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(VIDEO_MAJOR);
/*
* Local variables:
* c-basic-offset: 8
* End:
*/