vicam.c

linux内核源码

	/* it's not the end of the world if
	 * we fail to turn the camera off.
	 */

	set_camera_power(cam, 0);

	kfree(cam->raw_image);
	rvfree(cam->framebuf, VICAM_MAX_FRAME_SIZE * VICAM_FRAMES);
	kfree(cam->cntrlbuf);

	mutex_lock(&cam->cam_lock);

	cam->open_count--;
	open_count = cam->open_count;
	udev = cam->udev;

	mutex_unlock(&cam->cam_lock);

	if (!open_count && !udev) {
		kfree(cam);
	}

	return 0;
}

static void vicam_decode_color(const u8 *data, u8 *rgb)
{
	/* vicam_decode_color - Convert from Vicam Y-Cr-Cb to RGB
	 * Copyright (C) 2002 Monroe Williams ([e-mail])
	 */

	int i, prevY, nextY;

	prevY = 512;
	nextY = 512;

	data += VICAM_HEADER_SIZE;

	for( i = 0; i < 240; i++, data += 512 ) {
		const int y = ( i * 242 ) / 240;

		int j, prevX, nextX;
		int Y, Cr, Cb;

		if ( y == 242 - 1 ) {
			nextY = -512;
		}

		prevX = 1;
		nextX = 1;

		for ( j = 0; j < 320; j++, rgb += 3 ) {
			const int x = ( j * 512 ) / 320;
			const u8 * const src = &data[x];

			if ( x == 512 - 1 ) {
				nextX = -1;
			}

			Cr = ( src[prevX] - src[0] ) +
				( src[nextX] - src[0] );
			Cr /= 2;

			Cb = ( src[prevY] - src[prevX + prevY] ) +
				( src[prevY] - src[nextX + prevY] ) +
				( src[nextY] - src[prevX + nextY] ) +
				( src[nextY] - src[nextX + nextY] );
			Cb /= 4;

			Y = 1160 * ( src[0] + ( Cr / 2 ) - 16 );

			if ( i & 1 ) {
				int Ct = Cr;
				Cr = Cb;
				Cb = Ct;
			}

			if ( ( x ^ i ) & 1 ) {
				Cr = -Cr;
				Cb = -Cb;
			}

			rgb[0] = clamp( ( ( Y + ( 2017 * Cb ) ) +
					500 ) / 900, 0, 255 );
			rgb[1] = clamp( ( ( Y - ( 392 * Cb ) -
					  ( 813 * Cr ) ) +
					  500 ) / 1000, 0, 255 );
			rgb[2] = clamp( ( ( Y + ( 1594 * Cr ) ) +
					500 ) / 1300, 0, 255 );

			prevX = -1;
		}

		prevY = -512;
	}
}

static void
read_frame(struct vicam_camera *cam, int framenum)
{
	unsigned char *request = cam->cntrlbuf;
	int realShutter;
	int n;
	int actual_length;

	if (cam->needsDummyRead) {
		cam->needsDummyRead = 0;
		read_frame(cam, framenum);
	}

	memset(request, 0, 16);
	request[0] = cam->gain;	// 0 = 0% gain, FF = 100% gain

	request[1] = 0;	// 512x242 capture

	request[2] = 0x90;	// the function of these two bytes
	request[3] = 0x07;	// is not yet understood

	if (cam->shutter_speed > 60) {
		// Short exposure
		realShutter =
		    ((-15631900 / cam->shutter_speed) + 260533) / 1000;
		request[4] = realShutter & 0xFF;
		request[5] = (realShutter >> 8) & 0xFF;
		request[6] = 0x03;
		request[7] = 0x01;
	} else {
		// Long exposure
		realShutter = 15600 / cam->shutter_speed - 1;
		request[4] = 0;
		request[5] = 0;
		request[6] = realShutter & 0xFF;
		request[7] = realShutter >> 8;
	}

	// Per John Markus Bjørndalen, byte at index 8 causes problems if it isn't 0
	request[8] = 0;
	// bytes 9-15 do not seem to affect exposure or image quality

	mutex_lock(&cam->cam_lock);

	if (!cam->udev) {
		goto done;
	}

	n = __send_control_msg(cam, 0x51, 0x80, 0, request, 16);

	if (n < 0) {
		printk(KERN_ERR
		       " Problem sending frame capture control message");
		goto done;
	}

	n = usb_bulk_msg(cam->udev,
			 usb_rcvbulkpipe(cam->udev, cam->bulkEndpoint),
			 cam->raw_image,
			 512 * 242 + 128, &actual_length, 10000);

	if (n < 0) {
		printk(KERN_ERR "Problem during bulk read of frame data: %d\n",
		       n);
	}

 done:
	mutex_unlock(&cam->cam_lock);
}

static ssize_t
vicam_read( struct file *file, char __user *buf, size_t count, loff_t *ppos )
{
	struct vicam_camera *cam = file->private_data;

	DBG("read %d bytes.\n", (int) count);

	if (*ppos >= VICAM_MAX_FRAME_SIZE) {
		*ppos = 0;
		return 0;
	}

	if (*ppos == 0) {
		read_frame(cam, 0);
		vicam_decode_color(cam->raw_image,
				   cam->framebuf +
				   0 * VICAM_MAX_FRAME_SIZE);
	}

	count = min_t(size_t, count, VICAM_MAX_FRAME_SIZE - *ppos);

	if (copy_to_user(buf, &cam->framebuf[*ppos], count)) {
		count = -EFAULT;
	} else {
		*ppos += count;
	}

	if (count == VICAM_MAX_FRAME_SIZE) {
		*ppos = 0;
	}

	return count;
}


static int
vicam_mmap(struct file *file, struct vm_area_struct *vma)
{
	// TODO: allocate the raw frame buffer if necessary
	unsigned long page, pos;
	unsigned long start = vma->vm_start;
	unsigned long size  = vma->vm_end-vma->vm_start;
	struct vicam_camera *cam = file->private_data;

	if (!cam)
		return -ENODEV;

	DBG("vicam_mmap: %ld\n", size);

	/* We let mmap allocate as much as it wants because Linux was adding 2048 bytes
	 * to the size the application requested for mmap and it was screwing apps up.
	 if (size > VICAM_FRAMES*VICAM_MAX_FRAME_SIZE)
	 return -EINVAL;
	 */

	pos = (unsigned long)cam->framebuf;
	while (size > 0) {
		page = vmalloc_to_pfn((void *)pos);
		if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
			return -EAGAIN;

		start += PAGE_SIZE;
		pos += PAGE_SIZE;
		if (size > PAGE_SIZE)
			size -= PAGE_SIZE;
		else
			size = 0;
	}

	return 0;
}

static const struct file_operations vicam_fops = {
	.owner		= THIS_MODULE,
	.open		= vicam_open,
	.release	= vicam_close,
	.read		= vicam_read,
	.mmap		= vicam_mmap,
	.ioctl		= vicam_ioctl,
	.compat_ioctl	= v4l_compat_ioctl32,
	.llseek		= no_llseek,
};

static struct video_device vicam_template = {
	.owner 		= THIS_MODULE,
	.name 		= "ViCam-based USB Camera",
	.type 		= VID_TYPE_CAPTURE,
	.fops 		= &vicam_fops,
	.minor 		= -1,
};

/* table of devices that work with this driver */
static struct usb_device_id vicam_table[] = {
	{USB_DEVICE(USB_VICAM_VENDOR_ID, USB_VICAM_PRODUCT_ID)},
	{USB_DEVICE(USB_COMPRO_VENDOR_ID, USB_COMPRO_PRODUCT_ID)},
	{}			/* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, vicam_table);

static struct usb_driver vicam_driver = {
	.name		= "vicam",
	.probe		= vicam_probe,
	.disconnect	= vicam_disconnect,
	.id_table	= vicam_table
};

/**
 *	vicam_probe
 *	@intf: the interface
 *	@id: the device id
 *
 *	Called by the usb core when a new device is connected that it thinks
 *	this driver might be interested in.
 */
static int
vicam_probe( struct usb_interface *intf, const struct usb_device_id *id)
{
	struct usb_device *dev = interface_to_usbdev(intf);
	int bulkEndpoint = 0;
	const struct usb_host_interface *interface;
	const struct usb_endpoint_descriptor *endpoint;
	struct vicam_camera *cam;

	printk(KERN_INFO "ViCam based webcam connected\n");

	interface = intf->cur_altsetting;

	DBG(KERN_DEBUG "Interface %d. has %u. endpoints!\n",
	       interface->desc.bInterfaceNumber, (unsigned) (interface->desc.bNumEndpoints));
	endpoint = &interface->endpoint[0].desc;

	if ((endpoint->bEndpointAddress & 0x80) &&
	    ((endpoint->bmAttributes & 3) == 0x02)) {
		/* we found a bulk in endpoint */
		bulkEndpoint = endpoint->bEndpointAddress;
	} else {
		printk(KERN_ERR
		       "No bulk in endpoint was found ?! (this is bad)\n");
	}

	if ((cam =
	     kzalloc(sizeof (struct vicam_camera), GFP_KERNEL)) == NULL) {
		printk(KERN_WARNING
		       "could not allocate kernel memory for vicam_camera struct\n");
		return -ENOMEM;
	}


	cam->shutter_speed = 15;

	mutex_init(&cam->cam_lock);

	memcpy(&cam->vdev, &vicam_template,
	       sizeof (vicam_template));
	cam->vdev.priv = cam;	// sort of a reverse mapping for those functions that get vdev only

	cam->udev = dev;
	cam->bulkEndpoint = bulkEndpoint;

	if (video_register_device(&cam->vdev, VFL_TYPE_GRABBER, -1) == -1) {
		kfree(cam);
		printk(KERN_WARNING "video_register_device failed\n");
		return -EIO;
	}

	printk(KERN_INFO "ViCam webcam driver now controlling video device %d\n",cam->vdev.minor);

	usb_set_intfdata (intf, cam);

	return 0;
}

static void
vicam_disconnect(struct usb_interface *intf)
{
	int open_count;
	struct vicam_camera *cam = usb_get_intfdata (intf);
	usb_set_intfdata (intf, NULL);

	/* we must unregister the device before taking its
	 * cam_lock. This is because the video open call
	 * holds the same lock as video unregister. if we
	 * unregister inside of the cam_lock and open also
	 * uses the cam_lock, we get deadlock.
	 */

	video_unregister_device(&cam->vdev);

	/* stop the camera from being used */

	mutex_lock(&cam->cam_lock);

	/* mark the camera as gone */

	cam->udev = NULL;

	/* the only thing left to do is synchronize with
	 * our close/release function on who should release
	 * the camera memory. if there are any users using the
	 * camera, it's their job. if there are no users,
	 * it's ours.
	 */

	open_count = cam->open_count;

	mutex_unlock(&cam->cam_lock);

	if (!open_count) {
		kfree(cam);
	}

	printk(KERN_DEBUG "ViCam-based WebCam disconnected\n");
}

/*
 */
static int __init
usb_vicam_init(void)
{
	int retval;
	DBG(KERN_INFO "ViCam-based WebCam driver startup\n");
	retval = usb_register(&vicam_driver);
	if (retval)
		printk(KERN_WARNING "usb_register failed!\n");
	return retval;
}

static void __exit
usb_vicam_exit(void)
{
	DBG(KERN_INFO
	       "ViCam-based WebCam driver shutdown\n");

	usb_deregister(&vicam_driver);
}

module_init(usb_vicam_init);
module_exit(usb_vicam_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");