/*
 * CDC Ethernet based networking peripherals
 * Copyright (C) 2003-2005 by David Brownell
 *
 * 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
 */

// #define	DEBUG			// error path messages, extra info
// #define	VERBOSE			// more; success messages

#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ctype.h>
#include <linux/ethtool.h>
#include <linux/workqueue.h>
#include <linux/mii.h>
#include <linux/usb.h>
#include <linux/usb_cdc.h>

#include "usbnet.h"


/*
 * probes control interface, claims data interface, collects the bulk
 * endpoints, activates data interface (if needed), maybe sets MTU.
 * all pure cdc, except for certain firmware workarounds, and knowing
 * that rndis uses one different rule.
 */
int usbnet_generic_cdc_bind(struct usbnet *dev, struct usb_interface *intf)
{
	u8				*buf = intf->cur_altsetting->extra;
	int				len = intf->cur_altsetting->extralen;
	struct usb_interface_descriptor	*d;
	struct cdc_state		*info = (void *) &dev->data;
	int				status;
	int				rndis;
	struct usb_driver		*driver = driver_of(intf);

	if (sizeof dev->data < sizeof *info)
		return -EDOM;

	/* expect strict spec conformance for the descriptors, but
	 * cope with firmware which stores them in the wrong place
	 */
	if (len == 0 && dev->udev->actconfig->extralen) {
		/* Motorola SB4100 (and others: Brad Hards says it's
		 * from a Broadcom design) put CDC descriptors here
		 */
		buf = dev->udev->actconfig->extra;
		len = dev->udev->actconfig->extralen;
		if (len)
			dev_dbg(&intf->dev,
				"CDC descriptors on config\n");
	}

	/* this assumes that if there's a non-RNDIS vendor variant
	 * of cdc-acm, it'll fail RNDIS requests cleanly.
	 */
	rndis = (intf->cur_altsetting->desc.bInterfaceProtocol == 0xff);

	memset(info, 0, sizeof *info);
	info->control = intf;
	while (len > 3) {
		if (buf [1] != USB_DT_CS_INTERFACE)
			goto next_desc;

		/* use bDescriptorSubType to identify the CDC descriptors.
		 * We expect devices with CDC header and union descriptors.
		 * For CDC Ethernet we need the ethernet descriptor.
		 * For RNDIS, ignore two (pointless) CDC modem descriptors
		 * in favor of a complicated OID-based RPC scheme doing what
		 * CDC Ethernet achieves with a simple descriptor.
		 */
		switch (buf [2]) {
		case USB_CDC_HEADER_TYPE:
			if (info->header) {
				dev_dbg(&intf->dev, "extra CDC header\n");
				goto bad_desc;
			}
			info->header = (void *) buf;
			if (info->header->bLength != sizeof *info->header) {
				dev_dbg(&intf->dev, "CDC header len %u\n",
					info->header->bLength);
				goto bad_desc;
			}
			break;
		case USB_CDC_UNION_TYPE:
			if (info->u) {
				dev_dbg(&intf->dev, "extra CDC union\n");
				goto bad_desc;
			}
			info->u = (void *) buf;
			if (info->u->bLength != sizeof *info->u) {
				dev_dbg(&intf->dev, "CDC union len %u\n",
					info->u->bLength);
				goto bad_desc;
			}

			/* we need a master/control interface (what we're
			 * probed with) and a slave/data interface; union
			 * descriptors sort this all out.
			 */
			info->control = usb_ifnum_to_if(dev->udev,
						info->u->bMasterInterface0);
			info->data = usb_ifnum_to_if(dev->udev,
						info->u->bSlaveInterface0);
			if (!info->control || !info->data) {
				dev_dbg(&intf->dev,
					"master #%u/%p slave #%u/%p\n",
					info->u->bMasterInterface0,
					info->control,
					info->u->bSlaveInterface0,
					info->data);
				goto bad_desc;
			}
			if (info->control != intf) {
				dev_dbg(&intf->dev, "bogus CDC Union\n");
				/* Ambit USB Cable Modem (and maybe others)
				 * interchanges master and slave interface.
				 */
				if (info->data == intf) {
					info->data = info->control;
					info->control = intf;
				} else
					goto bad_desc;
			}

			/* a data interface altsetting does the real i/o */
			d = &info->data->cur_altsetting->desc;
			if (d->bInterfaceClass != USB_CLASS_CDC_DATA) {
				dev_dbg(&intf->dev, "slave class %u\n",
					d->bInterfaceClass);
				goto bad_desc;
			}
			break;
		case USB_CDC_ETHERNET_TYPE:
			if (info->ether) {
				dev_dbg(&intf->dev, "extra CDC ether\n");
				goto bad_desc;
			}
			info->ether = (void *) buf;
			if (info->ether->bLength != sizeof *info->ether) {
				dev_dbg(&intf->dev, "CDC ether len %u\n",
					info->ether->bLength);
				goto bad_desc;
			}
			dev->hard_mtu = le16_to_cpu(
						info->ether->wMaxSegmentSize);
			/* because of Zaurus, we may be ignoring the host
			 * side link address we were given.
			 */
			break;
		}
next_desc:
		len -= buf [0];	/* bLength */
		buf += buf [0];
	}

	if (!info->header || !info->u || (!rndis && !info->ether)) {
		dev_dbg(&intf->dev, "missing cdc %s%s%sdescriptor\n",
			info->header ? "" : "header ",
			info->u ? "" : "union ",
			info->ether ? "" : "ether ");
		goto bad_desc;
	}

	/* claim data interface and set it up ... with side effects.
	 * network traffic can't flow until an altsetting is enabled.
	 */
	status = usb_driver_claim_interface(driver, info->data, dev);
	if (status < 0)
		return status;
	status = usbnet_get_endpoints(dev, info->data);
	if (status < 0) {
		/* ensure immediate exit from usbnet_disconnect */
		usb_set_intfdata(info->data, NULL);
		usb_driver_release_interface(driver, info->data);
		return status;
	}

	/* status endpoint: optional for CDC Ethernet, not RNDIS (or ACM) */
	dev->status = NULL;
	if (info->control->cur_altsetting->desc.bNumEndpoints == 1) {
		struct usb_endpoint_descriptor	*desc;

		dev->status = &info->control->cur_altsetting->endpoint [0];
		desc = &dev->status->desc;
		if (desc->bmAttributes != USB_ENDPOINT_XFER_INT
				|| !(desc->bEndpointAddress & USB_DIR_IN)
				|| (le16_to_cpu(desc->wMaxPacketSize)
					< sizeof(struct usb_cdc_notification))
				|| !desc->bInterval) {
			dev_dbg(&intf->dev, "bad notification endpoint\n");
			dev->status = NULL;
		}
	}
	if (rndis && !dev->status) {
		dev_dbg(&intf->dev, "missing RNDIS status endpoint\n");
		usb_set_intfdata(info->data, NULL);
		usb_driver_release_interface(driver, info->data);
		return -ENODEV;
	}
	return 0;

bad_desc:
	dev_info(&dev->udev->dev, "bad CDC descriptors\n");
	return -ENODEV;
}
EXPORT_SYMBOL_GPL(usbnet_generic_cdc_bind);

void usbnet_cdc_unbind(struct usbnet *dev, struct usb_interface *intf)
{
	struct cdc_state		*info = (void *) &dev->data;
	struct usb_driver		*driver = driver_of(intf);

	/* disconnect master --> disconnect slave */
	if (intf == info->control && info->data) {
		/* ensure immediate exit from usbnet_disconnect */
		usb_set_intfdata(info->data, NULL);
		usb_driver_release_interface(driver, info->data);
		info->data = NULL;
	}

	/* and vice versa (just in case) */
	else if (intf == info->data && info->control) {
		/* ensure immediate exit from usbnet_disconnect */
		usb_set_intfdata(info->control, NULL);
		usb_driver_release_interface(driver, info->control);
		info->control = NULL;
	}
}
EXPORT_SYMBOL_GPL(usbnet_cdc_unbind);


/*-------------------------------------------------------------------------
 *
 * Communications Device Class, Ethernet Control model
 *
 * Takes two interfaces.  The DATA interface is inactive till an altsetting
 * is selected.  Configuration data includes class descriptors.  There's
 * an optional status endpoint on the control interface.
 *
 * This should interop with whatever the 2.4 "CDCEther.c" driver
 * (by Brad Hards) talked with, with more functionality.
 *
 *-------------------------------------------------------------------------*/

static void dumpspeed(struct usbnet *dev, __le32 *speeds)
{
	if (netif_msg_timer(dev))
		devinfo(dev, "link speeds: %u kbps up, %u kbps down",
			__le32_to_cpu(speeds[0]) / 1000,
		__le32_to_cpu(speeds[1]) / 1000);
}

static void cdc_status(struct usbnet *dev, struct urb *urb)
{
	struct usb_cdc_notification	*event;

	if (urb->actual_length < sizeof *event)
		return;

	/* SPEED_CHANGE can get split into two 8-byte packets */
	if (test_and_clear_bit(EVENT_STS_SPLIT, &dev->flags)) {
		dumpspeed(dev, (__le32 *) urb->transfer_buffer);
		return;
	}

	event = urb->transfer_buffer;
	switch (event->bNotificationType) {
	case USB_CDC_NOTIFY_NETWORK_CONNECTION:
		if (netif_msg_timer(dev))
			devdbg(dev, "CDC: carrier %s",
					event->wValue ? "on" : "off");
		if (event->wValue)
			netif_carrier_on(dev->net);
		else
			netif_carrier_off(dev->net);
		break;
	case USB_CDC_NOTIFY_SPEED_CHANGE:	/* tx/rx rates */
		if (netif_msg_timer(dev))
			devdbg(dev, "CDC: speed change (len %d)",
					urb->actual_length);
		if (urb->actual_length != (sizeof *event + 8))
			set_bit(EVENT_STS_SPLIT, &dev->flags);
		else
			dumpspeed(dev, (__le32 *) &event[1]);
		break;
	/* USB_CDC_NOTIFY_RESPONSE_AVAILABLE can happen too (e.g. RNDIS),
	 * but there are no standard formats for the response data.
	 */
	default:
		deverr(dev, "CDC: unexpected notification %02x!",
				 event->bNotificationType);
		break;
	}
}

static u8 nibble(unsigned char c)
{
	if (likely(isdigit(c)))
		return c - '0';
	c = toupper(c);
	if (likely(isxdigit(c)))
		return 10 + c - 'A';
	return 0;
}

static inline int
get_ethernet_addr(struct usbnet *dev, struct usb_cdc_ether_desc *e)
{
	int 		tmp, i;
	unsigned char	buf [13];

	tmp = usb_string(dev->udev, e->iMACAddress, buf, sizeof buf);
	if (tmp != 12) {
		dev_dbg(&dev->udev->dev,
			"bad MAC string %d fetch, %d\n", e->iMACAddress, tmp);
		if (tmp >= 0)
			tmp = -EINVAL;
		return tmp;
	}
	for (i = tmp = 0; i < 6; i++, tmp += 2)
		dev->net->dev_addr [i] =
			(nibble(buf [tmp]) << 4) + nibble(buf [tmp + 1]);
	return 0;
}

static int cdc_bind(struct usbnet *dev, struct usb_interface *intf)
{
	int				status;
	struct cdc_state		*info = (void *) &dev->data;

	status = usbnet_generic_cdc_bind(dev, intf);
	if (status < 0)
		return status;

	status = get_ethernet_addr(dev, info->ether);
	if (status < 0) {
		usb_set_intfdata(info->data, NULL);
		usb_driver_release_interface(driver_of(intf), info->data);
		return status;
	}

	/* FIXME cdc-ether has some multicast code too, though it complains
	 * in routine cases.  info->ether describes the multicast support.
	 * Implement that here, manipulating the cdc filter as needed.
	 */
	return 0;
}

static const struct driver_info	cdc_info = {
	.description =	"CDC Ethernet Device",
	.flags =	FLAG_ETHER,
	// .check_connect = cdc_check_connect,
	.bind =		cdc_bind,
	.unbind =	usbnet_cdc_unbind,
	.status =	cdc_status,
};

/*-------------------------------------------------------------------------*/


static const struct usb_device_id	products [] = {
/*
 * BLACKLIST !!
 *
 * First blacklist any products that are egregiously nonconformant
 * with the CDC Ethernet specs.  Minor braindamage we cope with; when
 * they're not even trying, needing a separate driver is only the first
 * of the differences to show up.
 */

#define	ZAURUS_MASTER_INTERFACE \
	.bInterfaceClass	= USB_CLASS_COMM, \
	.bInterfaceSubClass	= USB_CDC_SUBCLASS_ETHERNET, \
	.bInterfaceProtocol	= USB_CDC_PROTO_NONE

/* SA-1100 based Sharp Zaurus ("collie"), or compatible;
 * wire-incompatible with true CDC Ethernet implementations.
 * (And, it seems, needlessly so...)
 */
{
	.match_flags	=   USB_DEVICE_ID_MATCH_INT_INFO
			  | USB_DEVICE_ID_MATCH_DEVICE,
	.idVendor		= 0x04DD,
	.idProduct		= 0x8004,
	ZAURUS_MASTER_INTERFACE,
	.driver_info		= 0,
},

/* PXA-25x based Sharp Zaurii.  Note that it seems some of these
 * (later models especially) may have shipped only with firmware
 * advertising false "CDC MDLM" compatibility ... but we're not
 * clear which models did that, so for now let's assume the worst.
 */
{
	.match_flags	=   USB_DEVICE_ID_MATCH_INT_INFO
			  | USB_DEVICE_ID_MATCH_DEVICE,
	.idVendor		= 0x04DD,
	.idProduct		= 0x8005,	/* A-300 */
	ZAURUS_MASTER_INTERFACE,
	.driver_info		= 0,
}, {
	.match_flags	=   USB_DEVICE_ID_MATCH_INT_INFO
			  | USB_DEVICE_ID_MATCH_DEVICE,
	.idVendor		= 0x04DD,
	.idProduct		= 0x8006,	/* B-500/SL-5600 */
	ZAURUS_MASTER_INTERFACE,
	.driver_info		= 0,
}, {
	.match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
	          | USB_DEVICE_ID_MATCH_DEVICE,
	.idVendor		= 0x04DD,
	.idProduct		= 0x8007,	/* C-700 */
	ZAURUS_MASTER_INTERFACE,
	.driver_info		= 0,
}, {
	.match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
		 | USB_DEVICE_ID_MATCH_DEVICE,
	.idVendor               = 0x04DD,
	.idProduct              = 0x9031,	/* C-750 C-760 */
	ZAURUS_MASTER_INTERFACE,
	.driver_info		= 0,
}, {
	.match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
		 | USB_DEVICE_ID_MATCH_DEVICE,
	.idVendor               = 0x04DD,
	.idProduct              = 0x9032,	/* SL-6000 */
	ZAURUS_MASTER_INTERFACE,
	.driver_info		= 0,
}, {
	.match_flags    =   USB_DEVICE_ID_MATCH_INT_INFO
		 | USB_DEVICE_ID_MATCH_DEVICE,
	.idVendor               = 0x04DD,
	/* reported with some C860 units */
	.idProduct              = 0x9050,	/* C-860 */
	ZAURUS_MASTER_INTERFACE,
	.driver_info		= 0,
},

/*
 * WHITELIST!!!
 *
 * CDC Ether uses two interfaces, not necessarily consecutive.
 * We match the main interface, ignoring the optional device
 * class so we could handle devices that aren't exclusively
 * CDC ether.
 *
 * NOTE:  this match must come AFTER entries blacklisting devices
 * because of bugs/quirks in a given product (like Zaurus, above).
 */
{
	USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ETHERNET,
			USB_CDC_PROTO_NONE),
	.driver_info = (unsigned long) &cdc_info,
},
	{ },		// END
};
MODULE_DEVICE_TABLE(usb, products);

static struct usb_driver cdc_driver = {
	.owner =	THIS_MODULE,
	.name =		"cdc_ether",
	.id_table =	products,
	.probe =	usbnet_probe,
	.disconnect =	usbnet_disconnect,
	.suspend =	usbnet_suspend,
	.resume =	usbnet_resume,
};


static int __init cdc_init(void)
{
	BUG_ON((sizeof(((struct usbnet *)0)->data)
			< sizeof(struct cdc_state)));

 	return usb_register(&cdc_driver);
}
module_init(cdc_init);

static void __exit cdc_exit(void)
{
 	usb_deregister(&cdc_driver);
}
module_exit(cdc_exit);

MODULE_AUTHOR("David Brownell");
MODULE_DESCRIPTION("USB CDC Ethernet devices");
MODULE_LICENSE("GPL");