/******************************************************************************
   *  xusbatm.c -	dumb usbatm-based driver for modems initialized in userspace
   *
   *  Copyright (C) 2005 Duncan Sands, Roman Kagan (rkagan % mail ! ru)
   *
   *  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; either version 2 of the License, or (at your option)
   *  any later version.
   *
   *  This program is distributed in the hope that it will be useful, but WITHOUT
   *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   *  more details.
   *
   *  You should have received a copy of the GNU General Public License along with
   *  this program; if not, write to the Free Software Foundation, Inc., 59
   *  Temple Place - Suite 330, Boston, MA  02111-1307, USA.
   *
   ******************************************************************************/
  
  #include <linux/module.h>
  #include <linux/etherdevice.h>		/* for eth_random_addr() */
  
  #include "usbatm.h"
  
  
  #define XUSBATM_DRIVERS_MAX	8
  
  #define XUSBATM_PARM(name, type, parmtype, desc) \
  	static type name[XUSBATM_DRIVERS_MAX]; \
  	static unsigned int num_##name; \
  	module_param_array(name, parmtype, &num_##name, 0444); \
  	MODULE_PARM_DESC(name, desc)
  
  XUSBATM_PARM(vendor, unsigned short, ushort, "USB device vendor");
  XUSBATM_PARM(product, unsigned short, ushort, "USB device product");
  
  XUSBATM_PARM(rx_endpoint, unsigned char, byte, "rx endpoint number");
  XUSBATM_PARM(tx_endpoint, unsigned char, byte, "tx endpoint number");
  XUSBATM_PARM(rx_padding, unsigned char, byte, "rx padding (default 0)");
  XUSBATM_PARM(tx_padding, unsigned char, byte, "tx padding (default 0)");
  XUSBATM_PARM(rx_altsetting, unsigned char, byte, "rx altsetting (default 0)");
  XUSBATM_PARM(tx_altsetting, unsigned char, byte, "rx altsetting (default 0)");
  
  static const char xusbatm_driver_name[] = "xusbatm";
  
  static struct usbatm_driver xusbatm_drivers[XUSBATM_DRIVERS_MAX];
  static struct usb_device_id xusbatm_usb_ids[XUSBATM_DRIVERS_MAX + 1];
  static struct usb_driver xusbatm_usb_driver;
  
  static struct usb_interface *xusbatm_find_intf(struct usb_device *usb_dev, int altsetting, u8 ep)
  {
  	struct usb_host_interface *alt;
  	struct usb_interface *intf;
  	int i, j;
  
  	for (i = 0; i < usb_dev->actconfig->desc.bNumInterfaces; i++)
  		if ((intf = usb_dev->actconfig->interface[i]) && (alt = usb_altnum_to_altsetting(intf, altsetting)))
  			for (j = 0; j < alt->desc.bNumEndpoints; j++)
  				if (alt->endpoint[j].desc.bEndpointAddress == ep)
  					return intf;
  	return NULL;
  }
  
  static int xusbatm_capture_intf(struct usbatm_data *usbatm, struct usb_device *usb_dev,
  		struct usb_interface *intf, int altsetting, int claim)
  {
  	int ifnum = intf->altsetting->desc.bInterfaceNumber;
  	int ret;
  
  	if (claim && (ret = usb_driver_claim_interface(&xusbatm_usb_driver, intf, usbatm))) {
  		usb_err(usbatm, "%s: failed to claim interface %2d (%d)!
  ", __func__, ifnum, ret);
  		return ret;
  	}
  	if ((ret = usb_set_interface(usb_dev, ifnum, altsetting))) {
  		usb_err(usbatm, "%s: altsetting %2d for interface %2d failed (%d)!
  ", __func__, altsetting, ifnum, ret);
  		return ret;
  	}
  	return 0;
  }
  
  static void xusbatm_release_intf(struct usb_device *usb_dev, struct usb_interface *intf, int claimed)
  {
  	if (claimed) {
  		usb_set_intfdata(intf, NULL);
  		usb_driver_release_interface(&xusbatm_usb_driver, intf);
  	}
  }
  
  static int xusbatm_bind(struct usbatm_data *usbatm,
  			struct usb_interface *intf, const struct usb_device_id *id)
  {
  	struct usb_device *usb_dev = interface_to_usbdev(intf);
  	int drv_ix = id - xusbatm_usb_ids;
  	int rx_alt = rx_altsetting[drv_ix];
  	int tx_alt = tx_altsetting[drv_ix];
  	struct usb_interface *rx_intf = xusbatm_find_intf(usb_dev, rx_alt, rx_endpoint[drv_ix]);
  	struct usb_interface *tx_intf = xusbatm_find_intf(usb_dev, tx_alt, tx_endpoint[drv_ix]);
  	int ret;
  
  	usb_dbg(usbatm, "%s: binding driver %d: vendor %04x product %04x"
  		" rx: ep %02x padd %d alt %2d tx: ep %02x padd %d alt %2d
  ",
  		__func__, drv_ix, vendor[drv_ix], product[drv_ix],
  		rx_endpoint[drv_ix], rx_padding[drv_ix], rx_alt,
  		tx_endpoint[drv_ix], tx_padding[drv_ix], tx_alt);
  
  	if (!rx_intf || !tx_intf) {
  		if (!rx_intf)
  			usb_dbg(usbatm, "%s: no interface contains endpoint %02x in altsetting %2d
  ",
  				__func__, rx_endpoint[drv_ix], rx_alt);
  		if (!tx_intf)
  			usb_dbg(usbatm, "%s: no interface contains endpoint %02x in altsetting %2d
  ",
  				__func__, tx_endpoint[drv_ix], tx_alt);
  		return -ENODEV;
  	}
  
  	if ((rx_intf != intf) && (tx_intf != intf))
  		return -ENODEV;
  
  	if ((rx_intf == tx_intf) && (rx_alt != tx_alt)) {
  		usb_err(usbatm, "%s: altsettings clash on interface %2d (%2d vs %2d)!
  ", __func__,
  				rx_intf->altsetting->desc.bInterfaceNumber, rx_alt, tx_alt);
  		return -EINVAL;
  	}
  
  	usb_dbg(usbatm, "%s: rx If#=%2d; tx If#=%2d
  ", __func__,
  			rx_intf->altsetting->desc.bInterfaceNumber,
  			tx_intf->altsetting->desc.bInterfaceNumber);
  
  	if ((ret = xusbatm_capture_intf(usbatm, usb_dev, rx_intf, rx_alt, rx_intf != intf)))
  		return ret;
  
  	if ((tx_intf != rx_intf) && (ret = xusbatm_capture_intf(usbatm, usb_dev, tx_intf, tx_alt, tx_intf != intf))) {
  		xusbatm_release_intf(usb_dev, rx_intf, rx_intf != intf);
  		return ret;
  	}
  
  	return 0;
  }
  
  static void xusbatm_unbind(struct usbatm_data *usbatm,
  			   struct usb_interface *intf)
  {
  	struct usb_device *usb_dev = interface_to_usbdev(intf);
  	int i;
  
  	usb_dbg(usbatm, "%s entered
  ", __func__);
  
  	for (i = 0; i < usb_dev->actconfig->desc.bNumInterfaces; i++) {
  		struct usb_interface *cur_intf = usb_dev->actconfig->interface[i];
  
  		if (cur_intf && (usb_get_intfdata(cur_intf) == usbatm)) {
  			usb_set_intfdata(cur_intf, NULL);
  			usb_driver_release_interface(&xusbatm_usb_driver, cur_intf);
  		}
  	}
  }
  
  static int xusbatm_atm_start(struct usbatm_data *usbatm,
  			     struct atm_dev *atm_dev)
  {
  	atm_dbg(usbatm, "%s entered
  ", __func__);
  
  	/* use random MAC as we've no way to get it from the device */
  	eth_random_addr(atm_dev->esi);
  
  	return 0;
  }
  
  
  static int xusbatm_usb_probe(struct usb_interface *intf,
  			     const struct usb_device_id *id)
  {
  	return usbatm_usb_probe(intf, id,
  				xusbatm_drivers + (id - xusbatm_usb_ids));
  }
  
  static struct usb_driver xusbatm_usb_driver = {
  	.name		= xusbatm_driver_name,
  	.probe		= xusbatm_usb_probe,
  	.disconnect	= usbatm_usb_disconnect,
  	.id_table	= xusbatm_usb_ids
  };
  
  static int __init xusbatm_init(void)
  {
  	int i;
  
  	if (!num_vendor ||
  	    num_vendor != num_product ||
  	    num_vendor != num_rx_endpoint ||
  	    num_vendor != num_tx_endpoint) {
  		printk(KERN_WARNING "xusbatm: malformed module parameters
  ");
  		return -EINVAL;
  	}
  
  	for (i = 0; i < num_vendor; i++) {
  		rx_endpoint[i] |= USB_DIR_IN;
  		tx_endpoint[i] &= USB_ENDPOINT_NUMBER_MASK;
  
  		xusbatm_usb_ids[i].match_flags	= USB_DEVICE_ID_MATCH_DEVICE;
  		xusbatm_usb_ids[i].idVendor	= vendor[i];
  		xusbatm_usb_ids[i].idProduct	= product[i];
  
  		xusbatm_drivers[i].driver_name	= xusbatm_driver_name;
  		xusbatm_drivers[i].bind		= xusbatm_bind;
  		xusbatm_drivers[i].unbind	= xusbatm_unbind;
  		xusbatm_drivers[i].atm_start	= xusbatm_atm_start;
  		xusbatm_drivers[i].bulk_in	= rx_endpoint[i];
  		xusbatm_drivers[i].bulk_out	= tx_endpoint[i];
  		xusbatm_drivers[i].rx_padding	= rx_padding[i];
  		xusbatm_drivers[i].tx_padding	= tx_padding[i];
  	}
  
  	return usb_register(&xusbatm_usb_driver);
  }
  module_init(xusbatm_init);
  
  static void __exit xusbatm_exit(void)
  {
  	usb_deregister(&xusbatm_usb_driver);
  }
  module_exit(xusbatm_exit);
  
  MODULE_AUTHOR("Roman Kagan, Duncan Sands");
  MODULE_DESCRIPTION("Driver for USB ADSL modems initialized in userspace");
  MODULE_LICENSE("GPL");
  MODULE_VERSION("0.1");