Commit 154feaef authored by Gerd Knorr's avatar Gerd Knorr Committed by Linus Torvalds

[PATCH] videodev redesign

This patch is a redesign for videodev.[ch].  Changes:

- drop the function pointers (read/write/mmap/poll/...) from struct
  video_device, use struct file_operations directly instead.
  Dispatching to different drivers by minor number is done the same way
  soundcore.o handles this: swap file->f_fops at open() time.

- also drop the now obsolete video_red/write/mmap/poll/...  functions
  from videodev.c

- Stop using the BKL, use a mutex to protect open,register+unregister
  calls against races.

- provide a video_generic_ioctl() function which can (and should) be
  used by v4l drivers to handle copying from and to userspace.

- provide video_exclusive_open/release functions which can be used by
  v4l drivers to make sure only one process at a time opens the
  device.  They can be hooked directly into struct file_operations if
  some driver has nothing to initialize at open time (which is true
  for many drivers in drivers/media/radio/).

The move from function pointers in struct video_device to struct
file_operations does break all existing v4l drivers.  Thus I have a
large number of patches for the drivers in the kernel tree.  Most of it
is just the adoption to the videodev.[ch] changes, but I've also fixed a
small bug there and there while walking througth the source files.
parent ca715f04
......@@ -25,15 +25,13 @@
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/videodev.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/semaphore.h>
#include <linux/kmod.h>
#include <linux/videodev.h>
#define VIDEO_NUM_DEVICES 256
......@@ -42,6 +40,7 @@
*/
static struct video_device *video_device[VIDEO_NUM_DEVICES];
static DECLARE_MUTEX(videodev_lock);
#if defined(CONFIG_PROC_FS) && defined(CONFIG_VIDEO_PROC_FS)
......@@ -62,155 +61,138 @@ LIST_HEAD(videodev_proc_list);
#endif /* CONFIG_PROC_FS && CONFIG_VIDEO_PROC_FS */
/*
* Read will do some smarts later on. Buffer pin etc.
*/
static ssize_t video_read(struct file *file,
char *buf, size_t count, loff_t *ppos)
{
struct video_device *vfl=video_device[minor(file->f_dentry->d_inode->i_rdev)];
if(vfl->read)
return vfl->read(vfl, buf, count, file->f_flags&O_NONBLOCK);
else
return -EINVAL;
}
/*
* Write for now does nothing. No reason it shouldnt do overlay setting
* for some boards I guess..
*/
static ssize_t video_write(struct file *file, const char *buf,
size_t count, loff_t *ppos)
{
struct video_device *vfl=video_device[minor(file->f_dentry->d_inode->i_rdev)];
if(vfl->write)
return vfl->write(vfl, buf, count, file->f_flags&O_NONBLOCK);
else
return 0;
}
/*
* Poll to see if we're readable, can probably be used for timing on incoming
* frames, etc..
*/
static unsigned int video_poll(struct file *file, poll_table * wait)
struct video_device* video_devdata(struct file *file)
{
struct video_device *vfl=video_device[minor(file->f_dentry->d_inode->i_rdev)];
if(vfl->poll)
return vfl->poll(vfl, file, wait);
else
return 0;
return video_device[minor(file->f_dentry->d_inode->i_rdev)];
}
/*
* Open a video device.
*/
static int video_open(struct inode *inode, struct file *file)
{
unsigned int minor = minor(inode->i_rdev);
int err, retval = 0;
int err = 0;
struct video_device *vfl;
struct file_operations *old_fops;
if(minor>=VIDEO_NUM_DEVICES)
return -ENODEV;
lock_kernel();
down(&videodev_lock);
vfl=video_device[minor];
if(vfl==NULL) {
char modname[20];
up(&videodev_lock);
sprintf (modname, "char-major-%d-%d", VIDEO_MAJOR, minor);
request_module(modname);
down(&videodev_lock);
vfl=video_device[minor];
if (vfl==NULL) {
retval = -ENODEV;
goto error_out;
up(&videodev_lock);
return -ENODEV;
}
}
if(vfl->busy) {
retval = -EBUSY;
goto error_out;
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);
}
vfl->busy=1; /* In case vfl->open sleeps */
if(vfl->owner)
__MOD_INC_USE_COUNT(vfl->owner);
if(vfl->open)
{
err=vfl->open(vfl,0); /* Tell the device it is open */
if(err)
{
vfl->busy=0;
if(vfl->owner)
__MOD_DEC_USE_COUNT(vfl->owner);
unlock_kernel();
fops_put(old_fops);
up(&videodev_lock);
return err;
}
}
unlock_kernel();
return 0;
error_out:
unlock_kernel();
return retval;
}
/*
* Last close of a video for Linux device
* ioctl helper function -- handles userspace copying
*/
static int video_release(struct inode *inode, struct file *file)
{
struct video_device *vfl;
lock_kernel();
vfl=video_device[minor(inode->i_rdev)];
if(vfl->close)
vfl->close(vfl);
vfl->busy=0;
if(vfl->owner)
__MOD_DEC_USE_COUNT(vfl->owner);
unlock_kernel();
return 0;
}
static int video_ioctl(struct inode *inode, struct file *file,
int
video_generic_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct video_device *vfl=video_device[minor(inode->i_rdev)];
int err=vfl->ioctl(vfl, cmd, (void *)arg);
struct video_device *vfl = video_devdata(file);
char sbuf[128];
void *mbuf = NULL;
void *parg = NULL;
int err = -EINVAL;
if(err!=-ENOIOCTLCMD)
return err;
if (vfl->kernel_ioctl == NULL)
return -EINVAL;
/* Copy arguments into temp kernel buffer */
switch (_IOC_DIR(cmd)) {
case _IOC_NONE:
parg = (void *)arg;
break;
case _IOC_READ: /* some v4l ioctls are marked wrong ... */
case _IOC_WRITE:
case (_IOC_WRITE | _IOC_READ):
if (_IOC_SIZE(cmd) <= sizeof(sbuf)) {
parg = sbuf;
} else {
/* too big to allocate from stack */
mbuf = kmalloc(_IOC_SIZE(cmd),GFP_KERNEL);
if (NULL == mbuf)
return -ENOMEM;
parg = mbuf;
}
err = -EFAULT;
if (copy_from_user(parg, (void *)arg, _IOC_SIZE(cmd)))
goto out;
break;
}
/* call driver */
err = vfl->kernel_ioctl(inode, file, cmd, parg);
if (err == -ENOIOCTLCMD)
err = -EINVAL;
if (err < 0)
goto out;
switch(cmd)
/* Copy results into user buffer */
switch (_IOC_DIR(cmd))
{
default:
return -EINVAL;
case _IOC_READ:
case (_IOC_WRITE | _IOC_READ):
if (copy_to_user((void *)arg, parg, _IOC_SIZE(cmd)))
err = -EFAULT;
break;
}
out:
if (mbuf)
kfree(mbuf);
return err;
}
/*
* We need to do MMAP support
* open/release helper functions -- handle exclusive opens
*/
int video_mmap(struct file *file, struct vm_area_struct *vma)
extern int video_exclusive_open(struct inode *inode, struct file *file)
{
int ret = -EINVAL;
struct video_device *vfl=video_device[minor(file->f_dentry->d_inode->i_rdev)];
if(vfl->mmap) {
lock_kernel();
ret = vfl->mmap(vma, vfl, (char *)vma->vm_start,
(unsigned long)(vma->vm_end-vma->vm_start));
unlock_kernel();
struct video_device *vfl = video_devdata(file);
int retval = 0;
down(&vfl->lock);
if (vfl->users) {
retval = -EBUSY;
} else {
vfl->users++;
}
return ret;
up(&vfl->lock);
return retval;
}
extern int video_exclusive_release(struct inode *inode, struct file *file)
{
struct video_device *vfl = video_devdata(file);
vfl->users--;
return 0;
}
/*
......@@ -392,13 +374,10 @@ extern struct file_operations video_fops;
* %VFL_TYPE_RADIO - A radio card
*/
static DECLARE_MUTEX(videodev_register_lock);
int video_register_device(struct video_device *vfd, int type, int nr)
{
int i=0;
int base;
int err;
int end;
char *name_base;
char name[16];
......@@ -430,50 +409,36 @@ int video_register_device(struct video_device *vfd, int type, int nr)
}
/* pick a minor number */
down(&videodev_register_lock);
down(&videodev_lock);
if (-1 == nr) {
/* use first free */
for(i=base;i<end;i++)
if (NULL == video_device[i])
break;
if (i == end) {
up(&videodev_register_lock);
up(&videodev_lock);
return -ENFILE;
}
} else {
/* use the one the driver asked for */
i = base+nr;
if (NULL != video_device[i]) {
up(&videodev_register_lock);
up(&videodev_lock);
return -ENFILE;
}
}
video_device[i]=vfd;
vfd->minor=i;
up(&videodev_register_lock);
/* The init call may sleep so we book the slot out
then call */
MOD_INC_USE_COUNT;
if(vfd->initialize) {
err=vfd->initialize(vfd);
if(err<0) {
video_device[i]=NULL;
MOD_DEC_USE_COUNT;
return err;
}
}
up(&videodev_lock);
sprintf (name, "v4l/%s%d", name_base, i - base);
/*
* Start the device root only. Anything else
* has serious privacy issues.
*/
vfd->devfs_handle =
devfs_register (NULL, name, DEVFS_FL_DEFAULT,
VIDEO_MAJOR, vfd->minor,
S_IFCHR | S_IRUSR | S_IWUSR,
&video_fops,
NULL);
init_MUTEX(&vfd->lock);
#if defined(CONFIG_PROC_FS) && defined(CONFIG_VIDEO_PROC_FS)
sprintf (name, "%s%d", name_base, i - base);
......@@ -492,8 +457,9 @@ int video_register_device(struct video_device *vfd, int type, int nr)
void video_unregister_device(struct video_device *vfd)
{
down(&videodev_lock);
if(video_device[vfd->minor]!=vfd)
panic("vfd: bad unregister");
panic("videodev: bad unregister");
#if defined(CONFIG_PROC_FS) && defined(CONFIG_VIDEO_PROC_FS)
videodev_proc_destroy_dev (vfd);
......@@ -501,7 +467,7 @@ void video_unregister_device(struct video_device *vfd)
devfs_unregister (vfd->devfs_handle);
video_device[vfd->minor]=NULL;
MOD_DEC_USE_COUNT;
up(&videodev_lock);
}
......@@ -509,13 +475,7 @@ static struct file_operations video_fops=
{
owner: THIS_MODULE,
llseek: no_llseek,
read: video_read,
write: video_write,
ioctl: video_ioctl,
mmap: video_mmap,
open: video_open,
release: video_release,
poll: video_poll,
};
/*
......@@ -540,12 +500,9 @@ static int __init videodev_init(void)
static void __exit videodev_exit(void)
{
#ifdef MODULE
#if defined(CONFIG_PROC_FS) && defined(CONFIG_VIDEO_PROC_FS)
videodev_proc_destroy ();
#endif
#endif
devfs_unregister_chrdev(VIDEO_MAJOR, "video_capture");
}
......@@ -554,6 +511,10 @@ module_exit(videodev_exit)
EXPORT_SYMBOL(video_register_device);
EXPORT_SYMBOL(video_unregister_device);
EXPORT_SYMBOL(video_devdata);
EXPORT_SYMBOL(video_generic_ioctl);
EXPORT_SYMBOL(video_exclusive_open);
EXPORT_SYMBOL(video_exclusive_release);
MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("Device registrar for Video4Linux drivers");
......
......@@ -4,6 +4,18 @@
#include <linux/types.h>
#include <linux/version.h>
#if 0
/*
* v4l2 is still work-in-progress, integration planed for 2.5.x
* v4l2 project homepage: http://www.thedirks.org/v4l2/
* patches available from: http://bytesex.org/patches/
*/
# define HAVE_V4L2 1
# include <linux/videodev2.h>
#else
# undef HAVE_V4L2
#endif
#ifdef __KERNEL__
#include <linux/poll.h>
......@@ -14,23 +26,24 @@ struct video_device
{
struct module *owner;
char name[32];
int type;
int type; /* v4l1 */
int type2; /* v4l2 */
int hardware;
int minor;
int (*open)(struct video_device *, int mode);
void (*close)(struct video_device *);
long (*read)(struct video_device *, char *, unsigned long, int noblock);
/* Do we need a write method ? */
long (*write)(struct video_device *, const char *, unsigned long, int noblock);
#if LINUX_VERSION_CODE >= 0x020100
unsigned int (*poll)(struct video_device *, struct file *, poll_table *);
#endif
int (*ioctl)(struct video_device *, unsigned int , void *);
int (*mmap)(struct vm_area_struct *vma, struct video_device *, const char *, unsigned long);
int (*initialize)(struct video_device *);
/* new interface -- we will use file_operations directly
* like soundcore does.
* kernel_ioctl() will be called by video_generic_ioctl.
* video_generic_ioctl() does the userspace copying of the
* ioctl arguments */
struct file_operations *fops;
int (*kernel_ioctl)(struct inode *inode, struct file *file,
unsigned int cmd, void *arg);
void *priv; /* Used to be 'private' but that upsets C++ */
int busy;
int minor;
/* for videodev.c intenal usage -- don't touch */
int users;
struct semaphore lock;
devfs_handle_t devfs_handle;
};
......@@ -43,8 +56,13 @@ extern int video_register_device(struct video_device *, int type, int nr);
#define VFL_TYPE_VTX 3
extern void video_unregister_device(struct video_device *);
#endif
extern struct video_device* video_devdata(struct file*);
extern int video_exclusive_open(struct inode *inode, struct file *file);
extern int video_exclusive_release(struct inode *inode, struct file *file);
extern int video_generic_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg);
#endif /* __KERNEL__ */
#define VID_TYPE_CAPTURE 1 /* Can capture */
#define VID_TYPE_TUNER 2 /* Can tune */
......@@ -150,6 +168,7 @@ struct video_audio
#define VIDEO_AUDIO_VOLUME 4
#define VIDEO_AUDIO_BASS 8
#define VIDEO_AUDIO_TREBLE 16
#define VIDEO_AUDIO_BALANCE 32
char name[16];
#define VIDEO_SOUND_MONO 1
#define VIDEO_SOUND_STEREO 2
......@@ -379,4 +398,10 @@ struct video_code
#define VID_HARDWARE_MEYE 32 /* Sony Vaio MotionEye cameras */
#define VID_HARDWARE_CPIA2 33
#endif
#endif /* __LINUX_VIDEODEV_H */
/*
* Local variables:
* c-basic-offset: 8
* End:
*/
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