Hi, In 2.5.x I want to drop the open/read/write/poll/mmap/... function pointers from struct video_device and all the useless video_read/write/poll/mmap/... wrapper functions from videodev.c. Instead, I'd like to see the video4linux drivers use struct file_operations directly and handle the device registration like soundcore does it for the sound drivers: simply swap file->f_op in video_open(). The patch below does part one of the plan -- for 2.4.x kernels. It adds the fops pointer to struct video_device and makes video_open use it if available, so both old + new style drivers will work. It also provides a ioctl wrapper function which handles copying the ioctl args from/to userspace, so we have this at one place can drop all the copy_from/to_user calls within the v4l device driver ioctl handlers. Comments? Gerd [mailed to both lkml + video4linux list] -------------------------- cut here ------------------------- --- linux-2.4.18-pre8/include/linux/videodev.h Tue Feb 5 11:21:37 2002 +++ linux/include/linux/videodev.h Tue Feb 5 11:33:04 2002 @@ -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> @@ -12,22 +24,31 @@ struct video_device { struct module *owner; - char name[32]; - int type; + char name[32]; + int type; /* v4l1 */ + int type2; /* v4l2 */ int hardware; + /* old, obsolete interface -- to be removed some day (2.5.x ?) */ 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 video_device *, const char *, unsigned long); - int (*initialize)(struct video_device *); - void *priv; /* Used to be 'private' but that upsets C++ */ + 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; devfs_handle_t devfs_handle; @@ -42,8 +63,11 @@ #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_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 */ @@ -149,6 +173,7 @@ #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 @@ -378,4 +403,10 @@ #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: + */ --- linux-2.4.18-pre8/drivers/media/video/Config.in Tue Feb 5 11:21:40 2002 +++ linux/drivers/media/video/Config.in Tue Feb 5 11:33:04 2002 @@ -8,6 +8,7 @@ dep_tristate ' I2C on parallel port' CONFIG_I2C_PARPORT $CONFIG_PARPORT $CONFIG_I2C comment 'Video Adapters' +dep_tristate ' Skeleton Driver Video For Linux' CONFIG_VIDEO_SKELETON $CONFIG_VIDEO_DEV if [ "$CONFIG_I2C_ALGOBIT" = "y" -o "$CONFIG_I2C_ALGOBIT" = "m" ]; then dep_tristate ' BT848 Video For Linux' CONFIG_VIDEO_BT848 $CONFIG_VIDEO_DEV $CONFIG_PCI $CONFIG_I2C_ALGOBIT fi --- linux-2.4.18-pre8/drivers/media/video/Makefile Tue Feb 5 11:21:32 2002 +++ linux/drivers/media/video/Makefile Tue Feb 5 11:33:04 2002 @@ -33,6 +33,7 @@ obj-$(CONFIG_VIDEO_DEV) += videodev.o +obj-$(CONFIG_VIDEO_SKELETON) += skeleton.o obj-$(CONFIG_BUS_I2C) += i2c-old.o obj-$(CONFIG_VIDEO_BT848) += bttv.o msp3400.o tvaudio.o \ tda7432.o tda9875.o tuner.o --- linux-2.4.18-pre8/drivers/media/video/skeleton.c Tue Feb 5 11:33:04 2002 +++ linux/drivers/media/video/skeleton.c Tue Feb 5 12:27:18 2002 @@ -0,0 +1,249 @@ +/* + * video4linux driver skeleton + * + * You can build and insmod it. It doesn't do anything fancy, just + * prints some messages when the file_operations functions are called. + * + * written by Gerd Knorr <kraxel@xxxxxxxxxxx> + * this source file is public domain, you can do with it + * whatever you like ... + * + */ + +#include <linux/init.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/videodev.h> + +#define DEVNAME "skeleton" + +/* ------------------------------------------------------------------ */ + +struct device_data { + struct list_head devlist; + struct video_device vdev; + struct semaphore lock; + int users; + /* more device specific stuff */ +}; + +struct file_data { + struct device_data *dev; + + /* just some random value to show how to keep multiple file + * handles apart and decorate the debug printk's a bit */ + int cookie; + + /* more filehandle specific data */ +}; + +/* ------------------------------------------------------------------ */ + +static unsigned int exclusive = 0; +static unsigned int debug = 1; +static unsigned int video_nr = -1; +MODULE_PARM(debug,"i"); +MODULE_PARM_DESC(debug,"enable debug messages (default: on)"); +MODULE_PARM(exclusive,"i"); +MODULE_PARM_DESC(exclusive,"only one process can open the device (default: off)"); +MODULE_PARM(video_nr,"i"); +MODULE_PARM_DESC(video_nr,"device number"); + +MODULE_AUTHOR("Gerd Knorr"); +MODULE_DESCRIPTION("video4linux driver skeleton"); +MODULE_LICENSE("GPL and additional rights"); + +#define dprintk(fmt, arg...) if (debug) \ + printk(KERN_DEBUG DEVNAME ": " fmt, ## arg) + +static struct list_head skeldev; + +/* ------------------------------------------------------------------ */ + +static int skeleton_open(struct inode *inode, struct file *file) +{ + static int cookie = 42; + unsigned int minor = MINOR(inode->i_rdev); + struct device_data *h,*dev = NULL; + struct file_data *fh; + struct list_head *list; + + dprintk("open: looking for my device [minor=%d]\n",minor); + + list_for_each(list,&skeldev) { + h = list_entry(list, struct device_data, devlist); + if (h->vdev.minor == minor) + dev = h; + } + if (NULL == dev) + return -ENODEV; + + down(&dev->lock); + dprintk("open: device found (%d users)\n",dev->users); + if (exclusive && dev->users > 0) { + dprintk("open: device busy\n"); + up(&dev->lock); + return -EBUSY; + } + + /* allocate + initialize per filehandle data */ + fh = kmalloc(sizeof(*fh),GFP_KERNEL); + if (NULL == fh) + return -ENOMEM; + file->private_data = fh; + memset(fh,0,sizeof(*fh)); + fh->dev = dev; + fh->cookie = cookie++; + + dprintk("open successful [minor=%d,cookie=%d]\n", + dev->vdev.minor,fh->cookie); + dev->users++; + up(&dev->lock); + return 0; +} + +static int skeleton_release(struct inode *inode, struct file *file) +{ + struct file_data *fh = file->private_data; + struct device_data *dev = fh->dev; + + dprintk("release called [minor=%d,cookie=%d]\n", + dev->vdev.minor,fh->cookie); + file->private_data = NULL; + kfree(fh); + dev->users--; + return 0; +} + +static ssize_t +skeleton_read(struct file *file, char *data, size_t count, loff_t *ppos) +{ + struct file_data *fh = file->private_data; + struct device_data *dev = fh->dev; + + dprintk("read called [minor=%d,cookie=%d]\n", + dev->vdev.minor,fh->cookie); + return 0; /* EOF */ +} + +static int +skeleton_mmap(struct file *file, struct vm_area_struct * vma) +{ + struct file_data *fh = file->private_data; + struct device_data *dev = fh->dev; + + dprintk("mmap called [minor=%d,cookie=%d]\n", + dev->vdev.minor,fh->cookie); + return -EINVAL; +} + +/* + * This function is _not_ called directly, but from + * video_generic_ioctl (and maybe others). userspace + * copying is done already, arg is a kernel pointer. + */ +static int skeleton_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, void *arg) +{ + struct file_data *fh = file->private_data; + struct device_data *dev = fh->dev; + + dprintk("ioctl called [minor=%d,cookie=%d,cmd=0x%x,arg=%p]\n", + dev->vdev.minor,fh->cookie,cmd,arg); + switch (cmd) { + case VIDIOCGCAP: + { + struct video_capability *cap = arg; + memset(cap,0,sizeof(*cap)); + strcpy(cap->name,dev->vdev.name); + return 0; + } + /* all the ioctls go here */ + + default: + return -ENOIOCTLCMD; + } + return 0; +} + +static struct file_operations skeleton_fops = +{ + owner: THIS_MODULE, + open: skeleton_open, + release: skeleton_release, + read: skeleton_read, + mmap: skeleton_mmap, + ioctl: video_generic_ioctl, + llseek: no_llseek, +}; + +static struct video_device skeleton_template = +{ + name: "undef", + type: 0, + hardware: 0, + fops: &skeleton_fops, + kernel_ioctl: skeleton_ioctl, + minor: -1, +}; + +/* ------------------------------------------------------------------ */ + +int skeleton_initdev(char *name) +{ + struct device_data *dev; + int err; + + dev = kmalloc(sizeof(*dev),GFP_KERNEL); + if (NULL == dev) + return -ENOMEM; + memset(dev,0,sizeof(*dev)); + init_MUTEX(&dev->lock); + + /* initialize device here */ + + dev->vdev = skeleton_template; + strcpy(dev->vdev.name, name); + dev->vdev.priv = dev; + err = video_register_device(&dev->vdev,VFL_TYPE_GRABBER,video_nr); + if (err < 0) { + kfree(dev); + return err; + } + list_add_tail(&dev->devlist,&skeldev); + dprintk("registered device %s [minor=%d]\n",name,dev->vdev.minor); + return 0; +} + +int skeleton_init(void) +{ + dprintk("video4linux skeleton driver loaded\n"); + INIT_LIST_HEAD(&skeldev); + skeleton_initdev("skeleton-1"); + skeleton_initdev("skeleton-2"); + return 0; +} + +void skeleton_fini(void) +{ + struct device_data *dev; + + while (!list_empty(&skeldev)) { + dev = list_entry(skeldev.next, struct device_data, devlist); + video_unregister_device(&dev->vdev); + kfree(dev); + list_del(&dev->devlist); + } + dprintk("unloaded\n"); +} + +module_init(skeleton_init); +module_exit(skeleton_fini); + +/* + * Local variables: + * c-basic-offset: 8 + * End: + */ --- linux-2.4.18-pre8/drivers/media/video/videodev.c Tue Feb 5 11:21:16 2002 +++ linux/drivers/media/video/videodev.c Tue Feb 5 11:33:04 2002 @@ -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 @@ -70,7 +68,7 @@ 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)]; + struct video_device *vfl = video_devdata(file); if(vfl->read) return vfl->read(vfl, buf, count, file->f_flags&O_NONBLOCK); else @@ -86,13 +84,18 @@ 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)]; + struct video_device *vfl = video_devdata(file); if(vfl->write) return vfl->write(vfl, buf, count, file->f_flags&O_NONBLOCK); else return 0; } +struct video_device* video_devdata(struct file *file) +{ + return video_device[MINOR(file->f_dentry->d_inode->i_rdev)]; +} + /* * Poll to see if we're readable, can probably be used for timing on incoming * frames, etc.. @@ -100,7 +103,7 @@ static unsigned int video_poll(struct file *file, poll_table * wait) { - struct video_device *vfl=video_device[MINOR(file->f_dentry->d_inode->i_rdev)]; + struct video_device *vfl = video_devdata(file); if(vfl->poll) return vfl->poll(vfl, file, wait); else @@ -133,6 +136,22 @@ goto error_out; } } + if (vfl->fops) { + int err = 0; + struct file_operations *old_fops; + + unlock_kernel(); + 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); + return err; + } if(vfl->busy) { retval = -EBUSY; goto error_out; @@ -170,7 +189,7 @@ { struct video_device *vfl; lock_kernel(); - vfl=video_device[MINOR(inode->i_rdev)]; + vfl = video_devdata(file); if(vfl->close) vfl->close(vfl); vfl->busy=0; @@ -183,7 +202,7 @@ static int video_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { - struct video_device *vfl=video_device[MINOR(inode->i_rdev)]; + struct video_device *vfl = video_devdata(file); int err=vfl->ioctl(vfl, cmd, (void *)arg); if(err!=-ENOIOCTLCMD) @@ -203,7 +222,7 @@ int video_mmap(struct file *file, struct vm_area_struct *vma) { int ret = -EINVAL; - struct video_device *vfl=video_device[MINOR(file->f_dentry->d_inode->i_rdev)]; + struct video_device *vfl = video_devdata(file); if(vfl->mmap) { lock_kernel(); ret = vfl->mmap(vfl, (char *)vma->vm_start, @@ -214,6 +233,69 @@ } /* + * ioctl helper function -- handles userspace copying + */ +int +video_generic_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct video_device *vfl = video_devdata(file); + char sbuf[128]; + void *mbuf = NULL; + void *parg = NULL; + int err = -EINVAL; + + 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; + + /* Copy results into user buffer */ + switch (_IOC_DIR(cmd)) + { + 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; +} + +/* * /proc support */ @@ -554,6 +636,8 @@ EXPORT_SYMBOL(video_register_device); EXPORT_SYMBOL(video_unregister_device); +EXPORT_SYMBOL(video_devdata); +EXPORT_SYMBOL(video_generic_ioctl); MODULE_AUTHOR("Alan Cox"); MODULE_DESCRIPTION("Device registrar for Video4Linux drivers"); --- linux-2.4.18-pre8/Documentation/Configure.help Tue Feb 5 11:21:49 2002 +++ linux/Documentation/Configure.help Tue Feb 5 11:33:04 2002 @@ -21269,6 +21269,19 @@ To use this option, you have to check, that the "/proc file system support" (CONFIG_PROC_FS) is enabled too. +Skeleton Video Capture Driver +CONFIG_VIDEO_SKELETON + This code is a skeleton driver that only illustrates how V4L + drivers register and communicate with the Video for Linux subsystem. + It does nothing. + + This driver is also available as a module called skeleton.o ( = code + which can be inserted in and removed from the running kernel + whenever you want). If you want to compile it as a module, say M + here and read Documentation/modules.txt. + + If unsure, say N, otherwise say N anyway. + AIMSlab RadioTrack (aka RadioReveal) support CONFIG_RADIO_RTRACK Choose Y here if you have one of these FM radio cards, and then fill
