/*
   * Driver for loading USB isight firmware
   *
   * Copyright (C) 2008 Matthew Garrett <mjg@redhat.com>
   *
   * 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, version 2.
   *
   * The USB isight cameras in recent Apples are roughly compatible with the USB
   * video class specification, and can be driven by uvcvideo. However, they
   * need firmware to be loaded beforehand. After firmware loading, the device
   * detaches from the USB bus and reattaches with a new device ID. It can then
   * be claimed by the uvc driver.
   *
   * The firmware is non-free and must be extracted by the user. Tools to do this
   * are available at http://bersace03.free.fr/ift/
   *
   * The isight firmware loading was reverse engineered by Johannes Berg
   * <johannes@sipsolutions.de>, and this driver is based on code by Ronald
   * Bultje <rbultje@ronald.bitfreak.net>
   */
  
  #include <linux/usb.h>
  #include <linux/firmware.h>
  #include <linux/errno.h>
  #include <linux/module.h>

  #include <linux/slab.h>

  static const struct usb_device_id id_table[] = {

  	{USB_DEVICE(0x05ac, 0x8300)},
  	{},
  };
  
  MODULE_DEVICE_TABLE(usb, id_table);
  
  static int isight_firmware_load(struct usb_interface *intf,
  				const struct usb_device_id *id)
  {
  	struct usb_device *dev = interface_to_usbdev(intf);
  	int llen, len, req, ret = 0;
  	const struct firmware *firmware;

  	unsigned char *buf = kmalloc(50, GFP_KERNEL);

  	unsigned char data[4];

  	const u8 *ptr;

  
  	if (!buf)
  		return -ENOMEM;

  
  	if (request_firmware(&firmware, "isight.fw", &dev->dev) != 0) {
  		printk(KERN_ERR "Unable to load isight firmware
  ");

  		ret = -ENODEV;
  		goto out;

  	}
  
  	ptr = firmware->data;

  	buf[0] = 0x01;

  	if (usb_control_msg

  	    (dev, usb_sndctrlpipe(dev, 0), 0xa0, 0x40, 0xe600, 0, buf, 1,

  	     300) != 1) {
  		printk(KERN_ERR
  		       "Failed to initialise isight firmware loader
  ");
  		ret = -ENODEV;
  		goto out;
  	}

  	while (ptr+4 <= firmware->data+firmware->size) {

  		memcpy(data, ptr, 4);
  		len = (data[0] << 8 | data[1]);
  		req = (data[2] << 8 | data[3]);
  		ptr += 4;
  
  		if (len == 0x8001)
  			break;	/* success */
  		else if (len == 0)
  			continue;
  
  		for (; len > 0; req += 50) {

  			llen = min(len, 50);

  			len -= llen;

  			if (ptr+llen > firmware->data+firmware->size) {
  				printk(KERN_ERR
  				       "Malformed isight firmware");
  				ret = -ENODEV;
  				goto out;
  			}

  			memcpy(buf, ptr, llen);
  
  			ptr += llen;
  
  			if (usb_control_msg
  			    (dev, usb_sndctrlpipe(dev, 0), 0xa0, 0x40, req, 0,
  			     buf, llen, 300) != llen) {
  				printk(KERN_ERR
  				       "Failed to load isight firmware
  ");

  				ret = -ENODEV;
  				goto out;
  			}

  		}
  	}

  	buf[0] = 0x00;

  	if (usb_control_msg

  	    (dev, usb_sndctrlpipe(dev, 0), 0xa0, 0x40, 0xe600, 0, buf, 1,

  	     300) != 1) {
  		printk(KERN_ERR "isight firmware loading completion failed
  ");
  		ret = -ENODEV;
  	}

  out:

  	kfree(buf);

  	release_firmware(firmware);
  	return ret;
  }

  MODULE_FIRMWARE("isight.fw");

  static void isight_firmware_disconnect(struct usb_interface *intf)
  {
  }
  
  static struct usb_driver isight_firmware_driver = {
  	.name = "isight_firmware",
  	.probe = isight_firmware_load,
  	.disconnect = isight_firmware_disconnect,
  	.id_table = id_table,
  };

  module_usb_driver(isight_firmware_driver);

  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");