本文基於AM6C平臺Linux3.0.8核心。

一、ioctl呼叫流程

1.common/drivers/media/video/uvc/uvc_driver.c

module_init(uvc_init);

static int __init uvc_init(void){
  result = usb_register(&uvc_driver.driver);
}

struct uvc_driver uvc_driver = {
	.driver = {
		.name		= "uvcvideo",
		.probe		= uvc_probe,
		.disconnect	= uvc_disconnect,
		.suspend	= uvc_suspend,
		.resume		= uvc_resume,
		.reset_resume	= uvc_reset_resume,
		.id_table	= uvc_ids,
		.supports_autosuspend = 1,
	},
};

static int uvc_probe(struct usb_interface *intf, const struct usb_device_id *id){
  uvc_register_chains(dev)
}

static int uvc_register_chains(struct uvc_device *dev){
  ret = uvc_register_terms(dev, chain);
}

static int uvc_register_terms(struct uvc_device *dev, struct uvc_video_chain *chain){
  ret = uvc_register_video(dev, stream);
}

static int uvc_register_video(struct uvc_device *dev,struct uvc_streaming *stream){
  ret = uvc_video_init(stream);
  vdev = video_device_alloc();
  vdev->v4l2_dev = &dev->vdev;
  vdev->fops = &uvc_fops;
  vdev->release = uvc_release;
  strlcpy(vdev->name, dev->name, sizeof vdev->name);
  stream->vdev = vdev;
  video_set_drvdata(vdev, stream);
  ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
}
 

2.common/drivers/media/video/uvc/uvc_v4l2.c

const struct v4l2_file_operations uvc_fops = {
	.owner		= THIS_MODULE,
	.open		= uvc_v4l2_open,
	.release	= uvc_v4l2_release,
	.unlocked_ioctl	= uvc_v4l2_ioctl,
	.read		= uvc_v4l2_read,
	.mmap		= uvc_v4l2_mmap,
	.poll		= uvc_v4l2_poll,
#ifndef CONFIG_MMU
	.get_unmapped_area = uvc_v4l2_get_unmapped_area,
#endif
};

static long uvc_v4l2_ioctl(struct file *file, unsigned int cmd, unsigned long arg){
  return video_usercopy(file, cmd, arg, uvc_v4l2_do_ioctl);
}

static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg){
  return uvc_query_v4l2_ctrl(chain, arg);
}
 

3.common/drivers/media/video/uvc/uvc_ctrl.c

int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,struct v4l2_queryctrl *v4l2_ctrl){
  
}