patch-2.4.10 linux/drivers/usb/usbnet.c

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diff -u --recursive --new-file v2.4.9/linux/drivers/usb/usbnet.c linux/drivers/usb/usbnet.c
@@ -0,0 +1,1568 @@
+/*
+ * USB Host-to-Host Links
+ * Copyright (C) 2000-2001 by David Brownell <dbrownell@users.sourceforge.net>
+ */
+
+/*
+ * This is used for "USB networking", connecting USB hosts as peers.
+ *
+ * It can be used with USB "network cables", for IP-over-USB communications;
+ * Ethernet speeds without the Ethernet.  USB devices (including some PDAs)
+ * can support such links directly, replacing device-specific protocols
+ * with Internet standard ones.
+ *
+ * The links can be bridged using the Ethernet bridging (net/bridge)
+ * support as appropriate.  Devices currently supported include:
+ *
+ *	- AnchorChip 2720
+ *	- Belkin F5U104 (custom)
+ *	- "Linux Devices" (like iPaq and similar SA-1100 based PDAs)
+ *	- NetChip 1080 (interoperates with NetChip Win32 drivers)
+ *	- Prolific PL-2301/2302 (replaces "plusb" driver)
+ *
+ * USB devices can implement their side of this protocol at the cost
+ * of two bulk endpoints; it's not restricted to "cable" applications.
+ * See the LINUXDEV support.
+ *
+ * 
+ * TODO:
+ *
+ * This needs to be retested for bulk queuing problems ... earlier versions
+ * seemed to find different types of problems in each HCD.  Once they're fixed,
+ * re-enable queues to get higher bandwidth utilization (without needing
+ * to tweak MTU for larger packets).
+ *
+ * Add support for more "network cable" chips; interop with their Win32
+ * drivers may be a good thing.  Test the AnchorChip 2720 support..
+ * Figure out the initialization protocol used by the Prolific chips,
+ * for better robustness ... there's some powerup/reset handshake that's
+ * needed when only one end reboots.
+ *
+ * Use interrupt on PL230x to detect peer connect/disconnect, and call
+ * netif_carrier_{on,off} (?) appropriately.  For Net1080, detect peer
+ * connect/disconnect with async control messages.
+ *
+ * Find some way to report "peer connected" network hotplug events; it'll
+ * likely mean updating the networking layer.  (This has been discussed
+ * on the netdev list...)
+ *
+ * Craft smarter hotplug policy scripts ... ones that know how to arrange
+ * bridging with "brctl", and can handle static and dynamic ("pump") setups.
+ * Use those "peer connected" events.
+ *
+ *
+ * CHANGELOG:
+ *
+ * 13-sep-2000	experimental, new
+ * 10-oct-2000	usb_device_id table created. 
+ * 28-oct-2000	misc fixes; mostly, discard more TTL-mangled rx packets.
+ * 01-nov-2000	usb_device_id table and probing api update by
+ *		Adam J. Richter <adam@yggdrasil.com>.
+ * 18-dec-2000	(db) tx watchdog, "net1080" renaming to "usbnet", device_info
+ *		and prolific support, isolate net1080-specific bits, cleanup.
+ *		fix unlink_urbs oops in D3 PM resume code path.
+ * 02-feb-2001	(db) fix tx skb sharing, packet length, match_flags, ...
+ * 08-feb-2001	stubbed in "linuxdev", maybe the SA-1100 folk can use it;
+ *		AnchorChips 2720 support (from spec) for testing;
+ *		fix bit-ordering problem with ethernet multicast addr
+ * 19-feb-2001  Support for clearing halt conditions. SA1100 UDC support
+ *		updates. Oleg Drokin (green@iXcelerator.com)
+ * 25-mar-2001	More SA-1100 updates, including workaround for ip problem
+ *		expecting cleared skb->cb and framing change to match latest
+ *		handhelds.org version (Oleg).  Enable device IDs from the
+ *		Win32 Belkin driver; other cleanups (db).
+ * 16-jul-2001	Bugfixes for uhci oops-on-unplug, Belkin support, various
+ *		cleanups for problems not yet seen in the field. (db)
+ *
+ *-------------------------------------------------------------------------*/
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kmod.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/random.h>
+#include <asm/unaligned.h>
+
+// #define	DEBUG			// error path messages, extra info
+// #define	VERBOSE			// more; success messages
+// #define	REALLY_QUEUE
+
+#if !defined (DEBUG) && defined (CONFIG_USB_DEBUG)
+#   define DEBUG
+#endif
+#include <linux/usb.h>
+
+
+#define	CONFIG_USB_AN2720
+#define	CONFIG_USB_BELKIN_F5U104
+#define	CONFIG_USB_LINUXDEV
+#define	CONFIG_USB_NET1080
+#define	CONFIG_USB_PL2301
+
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
+ * Several dozen bytes of IPv4 data can fit in two such transactions.
+ * One maximum size Ethernet packet takes twenty four of them.
+ */
+#ifdef REALLY_QUEUE
+#define	RX_QLEN		4
+#define	TX_QLEN		4
+#else
+#define	RX_QLEN		1
+#define	TX_QLEN		1
+#endif
+
+// packets are always ethernet inside
+// ... except they can be bigger (up to 64K with this framing)
+#define MIN_PACKET	sizeof(struct ethhdr)
+#define MAX_PACKET	32768
+
+// reawaken network queue this soon after stopping; else watchdog barks
+#define TX_TIMEOUT_JIFFIES	(5*HZ)
+
+// for vendor-specific control operations
+#define	CONTROL_TIMEOUT_MS	(500)			/* msec */
+#define CONTROL_TIMEOUT_JIFFIES ((CONTROL_TIMEOUT_MS * HZ)/1000)
+
+// between wakeups
+#define UNLINK_TIMEOUT_JIFFIES ((3  /*ms*/ * HZ)/1000)
+
+/*-------------------------------------------------------------------------*/
+
+// list of all devices we manage
+static DECLARE_MUTEX (usbnet_mutex);
+static LIST_HEAD (usbnet_list);
+
+// randomly generated ethernet address
+static u8	node_id [ETH_ALEN];
+
+// state we keep for each device we handle
+struct usbnet {
+	// housekeeping
+	struct usb_device	*udev;
+	struct driver_info	*driver_info;
+	struct semaphore	mutex;
+	struct list_head	dev_list;
+	wait_queue_head_t	*wait;
+
+	// protocol/interface state
+	struct net_device	net;
+	struct net_device_stats	stats;
+	u16			packet_id;
+
+	// various kinds of pending driver work
+	struct sk_buff_head	rxq;
+	struct sk_buff_head	txq;
+	struct sk_buff_head	done;
+	struct tasklet_struct	bh;
+	struct tq_struct ctrl_task;
+};
+
+// device-specific info used by the driver
+struct driver_info {
+	char		*description;
+
+	int		flags;
+#define FLAG_FRAMING	0x0001		/* guard against device dropouts */ 
+
+	/* reset device ... can sleep */
+	int	(*reset)(struct usbnet *);
+
+	/* see if peer is connected ... can sleep */
+	int	(*check_connect)(struct usbnet *);
+
+	// FIXME -- also an interrupt mechanism
+
+	/* framework currently "knows" bulk EPs talk packets */
+	int		in;		/* rx endpoint */
+	int		out;		/* tx endpoint */
+	int		epsize;
+};
+
+#define EP_SIZE(usbnet)	((usbnet)->driver_info->epsize)
+
+// we record the state for each of our queued skbs
+enum skb_state {
+	illegal = 0,
+	tx_start, tx_done,
+	rx_start, rx_done, rx_cleanup
+};
+
+struct skb_data {	// skb->cb is one of these
+	struct urb		*urb;
+	struct usbnet		*dev;
+	enum skb_state		state;
+	size_t			length;
+};
+
+
+#define	mutex_lock(x)	down(x)
+#define	mutex_unlock(x)	up(x)
+
+#define	RUN_CONTEXT (in_irq () ? "in_irq" \
+			: (in_interrupt () ? "in_interrupt" : "can sleep"))
+
+/*-------------------------------------------------------------------------*/
+
+#ifdef DEBUG
+#define devdbg(usbnet, fmt, arg...) \
+	printk(KERN_DEBUG "%s: " fmt "\n" , (usbnet)->net.name, ## arg)
+#else
+#define devdbg(usbnet, fmt, arg...) do {} while(0)
+#endif
+
+#define devinfo(usbnet, fmt, arg...) \
+	printk(KERN_INFO "%s: " fmt "\n" , (usbnet)->net.name, ## arg)
+
+/*-------------------------------------------------------------------------
+ *
+ * NetChip framing of ethernet packets, supporting additional error
+ * checks for links that may drop bulk packets from inside messages.
+ * Odd USB length == always short read for last usb packet.
+ *	- nc_header
+ *	- Ethernet header (14 bytes)
+ *	- payload
+ *	- (optional padding byte, if needed so length becomes odd)
+ *	- nc_trailer
+ *
+ * This framing is to be avoided for non-NetChip devices.
+ */
+
+struct nc_header {		// packed:
+	u16	hdr_len;		// sizeof nc_header (LE, all)
+	u16	packet_len;		// payload size (including ethhdr)
+	u16	packet_id;		// detects dropped packets
+#define MIN_HEADER	6
+
+	// all else is optional, and must start with:
+	// u16	vendorId;		// from usb-if
+	// u16	productId;
+} __attribute__((__packed__));
+
+#define	PAD_BYTE	((unsigned char)0xAC)
+
+struct nc_trailer {
+	u16	packet_id;
+} __attribute__((__packed__));
+
+// packets may use FLAG_FRAMING and optional pad
+#define FRAMED_SIZE(mtu) (sizeof (struct nc_header) \
+				+ sizeof (struct ethhdr) \
+				+ (mtu) \
+				+ 1 \
+				+ sizeof (struct nc_trailer))
+
+#define MIN_FRAMED	FRAMED_SIZE(0)
+
+
+
+#ifdef	CONFIG_USB_AN2720
+
+/*-------------------------------------------------------------------------
+ *
+ * AnchorChips 2720 driver ... http://www.cypress.com
+ *
+ * This doesn't seem to have a way to detect whether the peer is
+ * connected, or need any reset handshaking.  It's got pretty big
+ * internal buffers (handles most of a frame's worth of data).
+ * Chip data sheets don't describe any vendor control messages.
+ *
+ *-------------------------------------------------------------------------*/
+
+static const struct driver_info	an2720_info = {
+	description:	"AnchorChips/Cypress 2720",
+	// no reset available!
+	// no check_connect available!
+
+	in: 2, out: 2,		// direction distinguishes these
+	epsize:	64,
+};
+
+#endif	/* CONFIG_USB_AN2720 */
+
+
+
+#ifdef	CONFIG_USB_BELKIN_F5U104
+
+/*-------------------------------------------------------------------------
+ *
+ * Belkin F5U104 ... two NetChip 2280 devices + Atmel microcontroller
+ *
+ *-------------------------------------------------------------------------*/
+
+static const struct driver_info	belkin_info = {
+	description:	"Belkin USB Direct Connect (F5U104)",
+
+	in: 1, out: 1,		// direction distinguishes these
+	epsize:	64,
+};
+
+#endif	/* CONFIG_USB_BELKIN_F5U104 */
+
+
+
+#ifdef	CONFIG_USB_LINUXDEV
+
+/*-------------------------------------------------------------------------
+ *
+ * This could talk to a device that uses Linux, such as a PDA or
+ * an embedded system, or in fact to any "smart" device using this
+ * particular mapping of USB and Ethernet.
+ *
+ * Such a Linux host would need a "USB Device Controller" hardware
+ * (not "USB Host Controller"), and a network driver talking to that
+ * hardware.
+ *
+ * One example is Intel's SA-1100 chip, which integrates basic USB
+ * support (arch/arm/sa1100/usb-eth.c); it's used in the iPaq PDA.
+ *
+ *-------------------------------------------------------------------------*/
+
+
+static const struct driver_info	linuxdev_info = {
+	description:	"Linux Device",
+	// no reset defined (yet?)
+	// no check_connect needed!
+	in: 2, out: 1,
+	epsize:	64,
+};
+
+#endif	/* CONFIG_USB_LINUXDEV */
+
+
+
+#ifdef	CONFIG_USB_NET1080
+
+/*-------------------------------------------------------------------------
+ *
+ * Netchip 1080 driver ... http://www.netchip.com
+ *
+ *-------------------------------------------------------------------------*/
+
+/*
+ * Zero means no timeout; else, how long a 64 byte bulk packet may be queued
+ * before the hardware drops it.  If that's done, the driver will need to
+ * frame network packets to guard against the dropped USB packets.  The win32
+ * driver sets this for both sides of the link.
+ */
+#define	NC_READ_TTL_MS	((u8)255)	// ms
+
+/*
+ * We ignore most registers and EEPROM contents.
+ */
+#define	REG_USBCTL	((u8)0x04)
+#define REG_TTL		((u8)0x10)
+#define REG_STATUS	((u8)0x11)
+
+/*
+ * Vendor specific requests to read/write data
+ */
+#define	REQUEST_REGISTER	((u8)0x10)
+#define	REQUEST_EEPROM		((u8)0x11)
+
+static int
+nc_vendor_read (struct usbnet *dev, u8 req, u8 regnum, u16 *retval_ptr)
+{
+	int status = usb_control_msg (dev->udev,
+		usb_rcvctrlpipe (dev->udev, 0),
+		req,
+		USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+		0, regnum,
+		retval_ptr, sizeof *retval_ptr,
+		CONTROL_TIMEOUT_JIFFIES);
+	if (status > 0)
+		status = 0;
+	if (!status)
+		le16_to_cpus (retval_ptr);
+	return status;
+}
+
+static inline int
+nc_register_read (struct usbnet *dev, u8 regnum, u16 *retval_ptr)
+{
+	return nc_vendor_read (dev, REQUEST_REGISTER, regnum, retval_ptr);
+}
+
+// no retval ... can become async, usable in_interrupt()
+static void
+nc_vendor_write (struct usbnet *dev, u8 req, u8 regnum, u16 value)
+{
+	usb_control_msg (dev->udev,
+		usb_sndctrlpipe (dev->udev, 0),
+		req,
+		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+		value, regnum,
+		0, 0,			// data is in setup packet
+		CONTROL_TIMEOUT_JIFFIES);
+}
+
+static inline void
+nc_register_write (struct usbnet *dev, u8 regnum, u16 value)
+{
+	nc_vendor_write (dev, REQUEST_REGISTER, regnum, value);
+}
+
+
+#if 0
+static void nc_dump_registers (struct usbnet *dev)
+{
+	u8	reg;
+	u16	*vp = kmalloc (sizeof (u16));
+
+	if (!vp) {
+		dbg ("no memory?");
+		return;
+	}
+
+	dbg ("%s registers:", dev->net.name);
+	for (reg = 0; reg < 0x20; reg++) {
+		int retval;
+
+		// reading some registers is trouble
+		if (reg >= 0x08 && reg <= 0xf)
+			continue;
+		if (reg >= 0x12 && reg <= 0x1e)
+			continue;
+
+		retval = nc_register_read (dev, reg, vp);
+		if (retval < 0)
+			dbg ("%s reg [0x%x] ==> error %d",
+				dev->net.name, reg, retval);
+		else
+			dbg ("%s reg [0x%x] = 0x%x",
+				dev->net.name, reg, *vp);
+	}
+	kfree (vp);
+}
+#endif
+
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * Control register
+ */
+
+#define	USBCTL_WRITABLE_MASK	0x1f0f
+// bits 15-13 reserved, r/o
+#define	USBCTL_ENABLE_LANG	(1 << 12)
+#define	USBCTL_ENABLE_MFGR	(1 << 11)
+#define	USBCTL_ENABLE_PROD	(1 << 10)
+#define	USBCTL_ENABLE_SERIAL	(1 << 9)
+#define	USBCTL_ENABLE_DEFAULTS	(1 << 8)
+// bits 7-4 reserved, r/o
+#define	USBCTL_FLUSH_OTHER	(1 << 3)
+#define	USBCTL_FLUSH_THIS	(1 << 2)
+#define	USBCTL_DISCONN_OTHER	(1 << 1)
+#define	USBCTL_DISCONN_THIS	(1 << 0)
+
+static inline void nc_dump_usbctl (struct usbnet *dev, u16 usbctl)
+{
+#ifdef DEBUG
+	devdbg (dev, "net1080 %03d/%03d usbctl 0x%x:%s%s%s%s%s;"
+			" this%s%s;"
+			" other%s%s; r/o 0x%x",
+		dev->udev->bus->busnum, dev->udev->devnum,
+		usbctl,
+		(usbctl & USBCTL_ENABLE_LANG) ? " lang" : "",
+		(usbctl & USBCTL_ENABLE_MFGR) ? " mfgr" : "",
+		(usbctl & USBCTL_ENABLE_PROD) ? " prod" : "",
+		(usbctl & USBCTL_ENABLE_SERIAL) ? " serial" : "",
+		(usbctl & USBCTL_ENABLE_DEFAULTS) ? " defaults" : "",
+
+		(usbctl & USBCTL_FLUSH_OTHER) ? " FLUSH" : "",
+		(usbctl & USBCTL_DISCONN_OTHER) ? " DIS" : "",
+		(usbctl & USBCTL_FLUSH_THIS) ? " FLUSH" : "",
+		(usbctl & USBCTL_DISCONN_THIS) ? " DIS" : "",
+		usbctl & ~USBCTL_WRITABLE_MASK
+		);
+#endif
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * Status register
+ */
+
+#define	STATUS_PORT_A		(1 << 15)
+
+#define	STATUS_CONN_OTHER	(1 << 14)
+#define	STATUS_SUSPEND_OTHER	(1 << 13)
+#define	STATUS_MAILBOX_OTHER	(1 << 12)
+#define	STATUS_PACKETS_OTHER(n)	(((n) >> 8) && 0x03)
+
+#define	STATUS_CONN_THIS	(1 << 6)
+#define	STATUS_SUSPEND_THIS	(1 << 5)
+#define	STATUS_MAILBOX_THIS	(1 << 4)
+#define	STATUS_PACKETS_THIS(n)	(((n) >> 0) && 0x03)
+
+#define	STATUS_UNSPEC_MASK	0x0c8c
+#define	STATUS_NOISE_MASK 	((u16)~(0x0303|STATUS_UNSPEC_MASK))
+
+
+static inline void nc_dump_status (struct usbnet *dev, u16 status)
+{
+#ifdef DEBUG
+	devdbg (dev, "net1080 %03d/%03d status 0x%x:"
+			" this (%c) PKT=%d%s%s%s;"
+			" other PKT=%d%s%s%s; unspec 0x%x",
+		dev->udev->bus->busnum, dev->udev->devnum,
+		status,
+
+		// XXX the packet counts don't seem right
+		// (1 at reset, not 0); maybe UNSPEC too
+
+		(status & STATUS_PORT_A) ? 'A' : 'B',
+		STATUS_PACKETS_THIS (status),
+		(status & STATUS_CONN_THIS) ? " CON" : "",
+		(status & STATUS_SUSPEND_THIS) ? " SUS" : "",
+		(status & STATUS_MAILBOX_THIS) ? " MBOX" : "",
+
+		STATUS_PACKETS_OTHER (status),
+		(status & STATUS_CONN_OTHER) ? " CON" : "",
+		(status & STATUS_SUSPEND_OTHER) ? " SUS" : "",
+		(status & STATUS_MAILBOX_OTHER) ? " MBOX" : "",
+
+		status & STATUS_UNSPEC_MASK
+		);
+#endif
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * TTL register
+ */
+
+#define	TTL_THIS(ttl)	(0x00ff & ttl)
+#define	TTL_OTHER(ttl)	(0x00ff & (ttl >> 8))
+#define MK_TTL(this,other)	((u16)(((other)<<8)|(0x00ff&(this))))
+
+static inline void nc_dump_ttl (struct usbnet *dev, u16 ttl)
+{
+#ifdef DEBUG
+	devdbg (dev, "net1080 %03d/%03d ttl 0x%x this = %d, other = %d",
+		dev->udev->bus->busnum, dev->udev->devnum,
+		ttl,
+
+		TTL_THIS (ttl),
+		TTL_OTHER (ttl)
+		);
+#endif
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int net1080_reset (struct usbnet *dev)
+{
+	u16		usbctl, status, ttl;
+	u16		*vp = kmalloc (sizeof (u16), GFP_KERNEL);
+	int		retval;
+
+	if (!vp)
+		return -ENOMEM;
+
+	// nc_dump_registers (dev);
+
+	if ((retval = nc_register_read (dev, REG_STATUS, vp)) < 0) {
+		dbg ("can't read dev %d status: %d", dev->udev->devnum, retval);
+		goto done;
+	}
+	status = *vp;
+	// nc_dump_status (dev, status);
+
+	if ((retval = nc_register_read (dev, REG_USBCTL, vp)) < 0) {
+		dbg ("can't read USBCTL, %d", retval);
+		goto done;
+	}
+	usbctl = *vp;
+	// nc_dump_usbctl (dev, usbctl);
+
+	nc_register_write (dev, REG_USBCTL,
+			USBCTL_FLUSH_THIS | USBCTL_FLUSH_OTHER);
+
+	if ((retval = nc_register_read (dev, REG_TTL, vp)) < 0) {
+		dbg ("can't read TTL, %d", retval);
+		goto done;
+	}
+	ttl = *vp;
+	// nc_dump_ttl (dev, ttl);
+
+	nc_register_write (dev, REG_TTL,
+			MK_TTL (NC_READ_TTL_MS, TTL_OTHER (ttl)) );
+	dbg ("%s: assigned TTL, %d ms", dev->net.name, NC_READ_TTL_MS);
+
+	devdbg (dev, "port %c, peer %sconnected",
+		(status & STATUS_PORT_A) ? 'A' : 'B',
+		(status & STATUS_CONN_OTHER) ? "" : "dis"
+		);
+	retval = 0;
+
+done:
+	kfree (vp);
+	return retval;
+}
+
+static int net1080_check_connect (struct usbnet *dev)
+{
+	int			retval;
+	u16			status;
+	u16			*vp = kmalloc (sizeof (u16), GFP_KERNEL);
+
+	if (!vp)
+		return -ENOMEM;
+	retval = nc_register_read (dev, REG_STATUS, vp);
+	status = *vp;
+	kfree (vp);
+	if (retval != 0) {
+		dbg ("%s net1080_check_conn read - %d", dev->net.name, retval);
+		return retval;
+	}
+	if ((status & STATUS_CONN_OTHER) != STATUS_CONN_OTHER)
+		return -ENOLINK;
+	return 0;
+}
+
+static const struct driver_info	net1080_info = {
+	description:	"NetChip TurboCONNECT",
+	flags:		FLAG_FRAMING,
+	reset:		net1080_reset,
+	check_connect:	net1080_check_connect,
+
+	in: 1, out: 1,		// direction distinguishes these
+	epsize:	64,
+};
+
+#endif /* CONFIG_USB_NET1080 */
+
+
+
+#ifdef CONFIG_USB_PL2301
+
+/*-------------------------------------------------------------------------
+ *
+ * Prolific PL-2301/PL-2302 driver ... http://www.prolifictech.com
+ *
+ *-------------------------------------------------------------------------*/
+
+/*
+ * Bits 0-4 can be used for software handshaking; they're set from
+ * one end, cleared from the other, "read" with the interrupt byte.
+ */
+#define	PL_S_EN		(1<<7)		/* (feature only) suspend enable */
+/* reserved bit -- rx ready (6) ? */
+#define	PL_TX_READY	(1<<5)		/* (interrupt only) transmit ready */
+#define	PL_RESET_OUT	(1<<4)		/* reset output pipe */
+#define	PL_RESET_IN	(1<<3)		/* reset input pipe */
+#define	PL_TX_C		(1<<2)		/* transmission complete */
+#define	PL_TX_REQ	(1<<1)		/* transmission received */
+#define	PL_PEER_E	(1<<0)		/* peer exists */
+
+static inline int
+pl_vendor_req (struct usbnet *dev, u8 req, u8 val, u8 index)
+{
+	return usb_control_msg (dev->udev,
+		usb_rcvctrlpipe (dev->udev, 0),
+		req,
+		USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+		val, index,
+		0, 0,
+		CONTROL_TIMEOUT_JIFFIES);
+}
+
+static inline int
+pl_clear_QuickLink_features (struct usbnet *dev, int val)
+{
+	return pl_vendor_req (dev, 1, (u8) val, 0);
+}
+
+static inline int
+pl_set_QuickLink_features (struct usbnet *dev, int val)
+{
+	return pl_vendor_req (dev, 3, (u8) val, 0);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int pl_reset (struct usbnet *dev)
+{
+	return pl_set_QuickLink_features (dev,
+		PL_S_EN|PL_RESET_OUT|PL_RESET_IN|PL_PEER_E);
+}
+
+static int pl_check_connect (struct usbnet *dev)
+{
+	// FIXME test interrupt data PL_PEER_E bit
+	// plus, there's some handshake done by
+	// the prolific win32 driver... 
+	dbg ("%s: assuming peer is connected", dev->net.name);
+	return 0;
+}
+
+static const struct driver_info	prolific_info = {
+	description:	"Prolific PL-2301/PL-2302",
+	reset:		pl_reset,
+	check_connect:	pl_check_connect,
+
+	in: 3, out: 2,
+	epsize:	64,
+};
+
+#endif /* CONFIG_USB_PL2301 */
+
+
+
+/*-------------------------------------------------------------------------
+ *
+ * Network Device Driver (peer link to "Host Device", from USB host)
+ *
+ *-------------------------------------------------------------------------*/
+
+static int usbnet_change_mtu (struct net_device *net, int new_mtu)
+{
+	struct usbnet	*dev = (struct usbnet *) net->priv;
+
+	if (new_mtu <= sizeof (struct ethhdr) || new_mtu > MAX_PACKET)
+		return -EINVAL;
+	if (((dev->driver_info->flags) & FLAG_FRAMING)) {
+		if (FRAMED_SIZE (new_mtu) > MAX_PACKET)
+			return -EINVAL;
+	// no second zero-length packet read wanted after mtu-sized packets
+	} else if (((new_mtu + sizeof (struct ethhdr)) % EP_SIZE (dev)) == 0)
+		return -EDOM;
+	net->mtu = new_mtu;
+	return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static struct net_device_stats *usbnet_get_stats (struct net_device *net)
+{
+	return &((struct usbnet *) net->priv)->stats;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* urb completions are currently in_irq; avoid doing real work then. */
+
+static void defer_bh (struct usbnet *dev, struct sk_buff *skb)
+{
+	struct sk_buff_head	*list = skb->list;
+	unsigned long		flags;
+
+	spin_lock_irqsave (&list->lock, flags);
+	__skb_unlink (skb, list);
+	spin_unlock (&list->lock);
+	spin_lock (&dev->done.lock);
+	__skb_queue_tail (&dev->done, skb);
+	if (dev->done.qlen == 1)
+		tasklet_schedule (&dev->bh);
+	spin_unlock_irqrestore (&dev->done.lock, flags);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void rx_complete (struct urb *urb);
+
+static void rx_submit (struct usbnet *dev, struct urb *urb, int flags)
+{
+	struct sk_buff		*skb;
+	struct skb_data		*entry;
+	int			retval = 0;
+	unsigned long		lockflags;
+	size_t			size;
+
+	size = (dev->driver_info->flags & FLAG_FRAMING)
+			? FRAMED_SIZE (dev->net.mtu)
+			: (sizeof (struct ethhdr) + dev->net.mtu);
+	if ((skb = alloc_skb (size, flags)) == 0) {
+		dbg ("no rx skb");
+		tasklet_schedule (&dev->bh);
+		usb_free_urb (urb);
+		return;
+	}
+
+	entry = (struct skb_data *) skb->cb;
+	entry->urb = urb;
+	entry->dev = dev;
+	entry->state = rx_start;
+	entry->length = 0;
+
+	FILL_BULK_URB (urb, dev->udev,
+		usb_rcvbulkpipe (dev->udev, dev->driver_info->in),
+		skb->data, size, rx_complete, skb);
+#ifdef	REALLY_QUEUE
+	urb->transfer_flags |= USB_QUEUE_BULK;
+#endif
+
+	spin_lock_irqsave (&dev->rxq.lock, lockflags);
+
+	if (netif_running (&dev->net)) {
+		if ((retval = usb_submit_urb (urb)) != 0) {
+			dbg ("%s rx submit, %d", dev->net.name, retval);
+			tasklet_schedule (&dev->bh);
+		} else {
+			__skb_queue_tail (&dev->rxq, skb);
+		}
+	} else {
+		dbg ("rx: stopped");
+		retval = -ENOLINK;
+	}
+	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
+	if (retval) {
+		dev_kfree_skb_any (skb);
+		usb_free_urb (urb);
+	}
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
+{
+	if (dev->driver_info->flags & FLAG_FRAMING) {
+		struct nc_header	*header;
+		struct nc_trailer	*trailer;
+
+		if (!(skb->len & 0x01)
+				|| MIN_FRAMED > skb->len
+				|| skb->len > FRAMED_SIZE (dev->net.mtu)) {
+			dev->stats.rx_frame_errors++;
+			dbg ("rx framesize %d range %d..%d mtu %d", skb->len,
+				MIN_FRAMED, FRAMED_SIZE (dev->net.mtu),
+				dev->net.mtu
+				);
+			goto error;
+		}
+
+		header = (struct nc_header *) skb->data;
+		le16_to_cpus (&header->hdr_len);
+		le16_to_cpus (&header->packet_len);
+		if (FRAMED_SIZE (header->packet_len) > MAX_PACKET) {
+			dev->stats.rx_frame_errors++;
+			dbg ("packet too big, %d", header->packet_len);
+			goto error;
+		} else if (header->hdr_len < MIN_HEADER) {
+			dev->stats.rx_frame_errors++;
+			dbg ("header too short, %d", header->hdr_len);
+			goto error;
+		} else if (header->hdr_len > MIN_HEADER) {
+			// out of band data for us?
+			dbg ("header OOB, %d bytes",
+				header->hdr_len - MIN_HEADER);
+			// switch (vendor/product ids) { ... }
+		}
+		skb_pull (skb, header->hdr_len);
+
+		trailer = (struct nc_trailer *)
+			(skb->data + skb->len - sizeof *trailer);
+		skb_trim (skb, skb->len - sizeof *trailer);
+
+		if ((header->packet_len & 0x01) == 0) {
+			if (skb->data [header->packet_len] != PAD_BYTE) {
+				dev->stats.rx_frame_errors++;
+				dbg ("bad pad");
+				goto error;
+			}
+			skb_trim (skb, skb->len - 1);
+		}
+		if (skb->len != header->packet_len) {
+			dev->stats.rx_frame_errors++;
+			dbg ("bad packet len %d (expected %d)",
+				skb->len, header->packet_len);
+			goto error;
+		}
+		if (header->packet_id != get_unaligned (&trailer->packet_id)) {
+			dev->stats.rx_fifo_errors++;
+			dbg ("(2+ dropped) rx packet_id mismatch 0x%x 0x%x",
+				header->packet_id, trailer->packet_id);
+			goto error;
+		}
+#if 0
+		devdbg (dev, "frame <rx h %d p %d id %d", header->hdr_len,
+			header->packet_len, header->packet_id);
+#endif
+	} else {
+		// we trust the network stack to remove
+		// the extra byte we may have appended
+	}
+
+	if (skb->len) {
+		int	status;
+
+// FIXME: eth_copy_and_csum "small" packets to new SKB (small < ~200 bytes) ?
+
+		skb->dev = &dev->net;
+		skb->protocol = eth_type_trans (skb, &dev->net);
+		dev->stats.rx_packets++;
+		dev->stats.rx_bytes += skb->len;
+
+#ifdef	VERBOSE
+		devdbg (dev, "< rx, len %d, type 0x%x",
+			skb->len + sizeof (struct ethhdr), skb->protocol);
+#endif
+		memset (skb->cb,0,sizeof(struct skb_data));
+		status = netif_rx (skb);
+		if (status != NET_RX_SUCCESS)
+			devdbg (dev, "netif_rx status %d", status);
+	} else {
+		dbg ("drop");
+error:
+		dev->stats.rx_errors++;
+		skb_queue_tail (&dev->done, skb);
+	}
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void rx_complete (struct urb *urb)
+{
+	struct sk_buff		*skb = (struct sk_buff *) urb->context;
+	struct skb_data		*entry = (struct skb_data *) skb->cb;
+	struct usbnet		*dev = entry->dev;
+	int			urb_status = urb->status;
+
+	skb_put (skb, urb->actual_length);
+	entry->state = rx_done;
+	entry->urb = 0;
+
+	switch (urb_status) {
+	    // success
+	    case 0:
+		if (MIN_PACKET > skb->len || skb->len > MAX_PACKET) {
+			entry->state = rx_cleanup;
+			dev->stats.rx_errors++;
+			dev->stats.rx_length_errors++;
+			dbg ("rx length %d", skb->len);
+		}
+		break;
+
+	    // software-driven interface shutdown
+	    case -ECONNRESET:		// usb-ohci, usb-uhci
+	    case -ECONNABORTED:		// uhci ... for usb-uhci, INTR
+		dbg ("%s shutdown, code %d", dev->net.name, urb_status);
+		entry->state = rx_cleanup;
+		// do urb frees only in the tasklet
+		entry->urb = urb;
+		urb = 0;
+		break;
+
+	    // data overrun ... flush fifo?
+	    case -EOVERFLOW:
+		dev->stats.rx_over_errors++;
+		// FALLTHROUGH
+	    
+	    default:
+		// on unplug we'll get a burst of ETIMEDOUT/EILSEQ
+		// till the khubd gets and handles its interrupt.
+		entry->state = rx_cleanup;
+		dev->stats.rx_errors++;
+		dbg ("%s rx: status %d", dev->net.name, urb_status);
+		break;
+	}
+
+	defer_bh (dev, skb);
+
+	if (urb) {
+		if (netif_running (&dev->net)) {
+			rx_submit (dev, urb, GFP_ATOMIC);
+			return;
+		}
+	}
+#ifdef	VERBOSE
+	dbg ("no read resubmitted");
+#endif /* VERBOSE */
+}
+
+/*-------------------------------------------------------------------------*/
+
+// unlink pending rx/tx; completion handlers do all other cleanup
+
+static int unlink_urbs (struct sk_buff_head *q)
+{
+	unsigned long		flags;
+	struct sk_buff		*skb, *skbnext;
+	int			count = 0;
+
+	spin_lock_irqsave (&q->lock, flags);
+	for (skb = q->next; skb != (struct sk_buff *) q; skb = skbnext) {
+		struct skb_data		*entry;
+		struct urb		*urb;
+		int			retval;
+
+		entry = (struct skb_data *) skb->cb;
+		urb = entry->urb;
+		skbnext = skb->next;
+
+		// during some PM-driven resume scenarios,
+		// these (async) unlinks complete immediately
+		retval = usb_unlink_urb (urb);
+		if (retval < 0)
+			dbg ("unlink urb err, %d", retval);
+		else
+			count++;
+	}
+	spin_unlock_irqrestore (&q->lock, flags);
+	return count;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+// precondition: never called in_interrupt
+
+static int usbnet_stop (struct net_device *net)
+{
+	struct usbnet		*dev = (struct usbnet *) net->priv;
+	int			temp;
+	DECLARE_WAIT_QUEUE_HEAD (unlink_wakeup); 
+	DECLARE_WAITQUEUE (wait, current);
+
+	mutex_lock (&dev->mutex);
+	netif_stop_queue(net);
+
+	devdbg (dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld",
+		dev->stats.rx_packets, dev->stats.tx_packets, 
+		dev->stats.rx_errors, dev->stats.tx_errors
+		);
+
+	// ensure there are no more active urbs
+	add_wait_queue (&unlink_wakeup, &wait);
+	dev->wait = &unlink_wakeup;
+	temp = unlink_urbs (&dev->txq) + unlink_urbs (&dev->rxq);
+
+	// maybe wait for deletions to finish.
+	while (skb_queue_len (&dev->rxq)
+			&& skb_queue_len (&dev->txq)
+			&& skb_queue_len (&dev->done)) {
+		current->state = TASK_UNINTERRUPTIBLE;
+		schedule_timeout (UNLINK_TIMEOUT_JIFFIES);
+		dbg ("waited for %d urb completions", temp);
+	}
+	dev->wait = 0;
+	remove_wait_queue (&unlink_wakeup, &wait); 
+
+	mutex_unlock (&dev->mutex);
+	return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+// posts reads, and enables write queing
+
+// precondition: never called in_interrupt
+
+static int usbnet_open (struct net_device *net)
+{
+	struct usbnet		*dev = (struct usbnet *) net->priv;
+	int			retval = 0;
+	struct driver_info	*info = dev->driver_info;
+
+	mutex_lock (&dev->mutex);
+
+	// put into "known safe" state
+	if (info->reset && (retval = info->reset (dev)) < 0) {
+		devinfo (dev, "open reset fail (%d) usbnet %03d/%03d, %s",
+			retval,
+			dev->udev->bus->busnum, dev->udev->devnum,
+			info->description);
+		goto done;
+	}
+
+	// insist peer be connected
+	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
+		devdbg (dev, "can't open; %d", retval);
+		goto done;
+	}
+
+	netif_start_queue (net);
+	devdbg (dev, "open: enable queueing (rx %d, tx %d) mtu %d %sframed",
+		RX_QLEN, TX_QLEN, dev->net.mtu,
+		(info->flags & FLAG_FRAMING) ? "" : "un"
+		);
+
+	// delay posting reads until we're fully open
+	tasklet_schedule (&dev->bh);
+done:
+	mutex_unlock (&dev->mutex);
+	return retval;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* usb_clear_halt cannot be called in interrupt context */
+
+static void
+tx_clear_halt(void *data)
+{
+	struct usbnet		*dev = data;
+
+	usb_clear_halt (dev->udev,
+		usb_sndbulkpipe (dev->udev, dev->driver_info->out));
+	netif_wake_queue (&dev->net);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void tx_complete (struct urb *urb)
+{
+	struct sk_buff		*skb = (struct sk_buff *) urb->context;
+	struct skb_data		*entry = (struct skb_data *) skb->cb;
+	struct usbnet		*dev = entry->dev;
+
+	if (urb->status == USB_ST_STALL) {
+		if (dev->ctrl_task.sync == 0) {
+			dev->ctrl_task.routine = tx_clear_halt;
+			dev->ctrl_task.data = dev;
+			schedule_task(&dev->ctrl_task);
+		} else {
+			dbg ("Cannot clear TX stall");
+		}
+	}
+	urb->dev = 0;
+	entry->state = tx_done;
+	defer_bh (dev, skb);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void usbnet_tx_timeout (struct net_device *net)
+{
+	struct usbnet		*dev = (struct usbnet *) net->priv;
+
+	unlink_urbs (&dev->txq);
+	tasklet_schedule (&dev->bh);
+
+	// FIXME: device recovery -- reset?
+}
+
+/*-------------------------------------------------------------------------*/
+
+static inline struct sk_buff *fixup_skb (struct sk_buff *skb, int flags)
+{
+	int			padlen;
+	struct sk_buff		*skb2;
+
+	padlen = ((skb->len + sizeof (struct nc_header)
+			+ sizeof (struct nc_trailer)) & 0x01) ? 0 : 1;
+	if (!skb_cloned (skb)) {
+		int	headroom = skb_headroom (skb);
+		int	tailroom = skb_tailroom (skb);
+
+		if ((padlen + sizeof (struct nc_trailer)) <= tailroom
+			    && sizeof (struct nc_header) <= headroom)
+			return skb;
+
+		if ((sizeof (struct nc_header) + padlen
+					+ sizeof (struct nc_trailer)) <
+				(headroom + tailroom)) {
+			skb->data = memmove (skb->head
+						+ sizeof (struct nc_header),
+					    skb->data, skb->len);
+			skb->tail = skb->data + skb->len;
+			return skb;
+		}
+	}
+	skb2 = skb_copy_expand (skb,
+				sizeof (struct nc_header),
+				sizeof (struct nc_trailer) + padlen,
+				flags);
+	dev_kfree_skb_any (skb);
+	return skb2;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int usbnet_start_xmit (struct sk_buff *skb, struct net_device *net)
+{
+	struct usbnet		*dev = (struct usbnet *) net->priv;
+	int			length = skb->len;
+	int			retval = NET_XMIT_SUCCESS;
+	struct urb		*urb = 0;
+	struct skb_data		*entry;
+	struct nc_header	*header = 0;
+	struct nc_trailer	*trailer = 0;
+	struct driver_info	*info = dev->driver_info;
+	int			flags;
+
+	flags = in_interrupt () ? GFP_ATOMIC : GFP_KERNEL;
+
+	if (info->flags & FLAG_FRAMING) {
+		struct sk_buff	*skb2;
+		skb2 = fixup_skb (skb, flags);
+		if (!skb2) {
+			dbg ("can't fixup skb");
+			goto drop;
+		}
+		skb = skb2;
+	}
+
+	if (!(urb = usb_alloc_urb (0))) {
+		dbg ("no urb");
+		goto drop;
+	}
+
+	entry = (struct skb_data *) skb->cb;
+	entry->urb = urb;
+	entry->dev = dev;
+	entry->state = tx_start;
+	entry->length = length;
+
+	if (info->flags & FLAG_FRAMING) {
+		header = (struct nc_header *) skb_push (skb, sizeof *header);
+		header->hdr_len = cpu_to_le16 (sizeof (*header));
+		header->packet_len = cpu_to_le16 (length);
+		if (!((skb->len + sizeof *trailer) & 0x01))
+			*skb_put (skb, 1) = PAD_BYTE;
+		trailer = (struct nc_trailer *) skb_put (skb, sizeof *trailer);
+	} else if ((length % EP_SIZE (dev)) == 0) {
+			if (skb_shared (skb)) {
+				struct sk_buff *skb2;
+				skb2 = skb_unshare (skb, flags);
+				if (!skb2) {
+					dbg ("can't unshare skb");
+					goto drop;
+				}
+				skb = skb2;
+			}
+			skb->len++;
+		}
+
+	FILL_BULK_URB (urb, dev->udev,
+			usb_sndbulkpipe (dev->udev, info->out),
+			skb->data, skb->len, tx_complete, skb);
+	// Idle-but-posted reads with UHCI really chew up
+	// PCI bandwidth unless FSBR is disabled
+	urb->transfer_flags |= USB_ASYNC_UNLINK | USB_NO_FSBR;
+#ifdef	REALLY_QUEUE
+	urb->transfer_flags |= USB_QUEUE_BULK;
+#endif
+	// FIXME urb->timeout = ... jiffies ... ;
+
+	spin_lock_irqsave (&dev->txq.lock, flags);
+	if (info->flags & FLAG_FRAMING) {
+		header->packet_id = cpu_to_le16 (dev->packet_id++);
+		put_unaligned (header->packet_id, &trailer->packet_id);
+#if 0
+		devdbg (dev, "frame >tx h %d p %d id %d",
+			header->hdr_len, header->packet_len,
+			header->packet_id);
+#endif
+	}
+
+	netif_stop_queue (net);
+	if ((retval = usb_submit_urb (urb)) != 0) {
+		netif_start_queue (net);
+		dbg ("%s tx: submit urb err %d", net->name, retval);
+	} else {
+		net->trans_start = jiffies;
+		__skb_queue_tail (&dev->txq, skb);
+		if (dev->txq.qlen < TX_QLEN)
+			netif_start_queue (net);
+	}
+	spin_unlock_irqrestore (&dev->txq.lock, flags);
+
+	if (retval) {
+		devdbg (dev, "drop, code %d", retval);
+drop:
+		retval = NET_XMIT_DROP;
+		dev->stats.tx_dropped++;
+		dev_kfree_skb_any (skb);
+		usb_free_urb (urb);
+#ifdef	VERBOSE
+	} else {
+		devdbg (dev, "> tx, len %d, type 0x%x",
+			length, skb->protocol);
+#endif
+	}
+	return retval;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+// tasklet ... work that avoided running in_irq()
+
+static void usbnet_bh (unsigned long param)
+{
+	struct usbnet		*dev = (struct usbnet *) param;
+	struct sk_buff		*skb;
+	struct skb_data		*entry;
+
+	while ((skb = skb_dequeue (&dev->done))) {
+		entry = (struct skb_data *) skb->cb;
+		switch (entry->state) {
+		    case rx_done:
+			entry->state = rx_cleanup;
+			rx_process (dev, skb);
+			continue;
+		    case tx_done:
+			if (entry->urb->status) {
+				// can this statistic become more specific?
+				dev->stats.tx_errors++;
+				dbg ("%s tx: err %d", dev->net.name,
+					entry->urb->status);
+			} else {
+				dev->stats.tx_packets++;
+				dev->stats.tx_bytes += entry->length;
+			}
+			// FALLTHROUGH:
+		    case rx_cleanup:
+			usb_free_urb (entry->urb);
+			dev_kfree_skb (skb);
+			continue;
+		    default:
+			dbg ("%s: bogus skb state %d",
+				dev->net.name, entry->state);
+		}
+	}
+
+	// waiting for all pending urbs to complete?
+	if (dev->wait) {
+		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
+			wake_up (dev->wait);
+		}
+
+	// or are we maybe short a few urbs?
+	} else if (netif_running (&dev->net)) {
+		int	temp = dev->rxq.qlen;
+
+		if (temp < RX_QLEN) {
+			struct urb	*urb;
+			int		i;
+			for (i = 0; i < 3 && dev->rxq.qlen < RX_QLEN; i++) {
+				if ((urb = usb_alloc_urb (0)) != 0)
+					rx_submit (dev, urb, GFP_ATOMIC);
+			}
+			if (temp != dev->rxq.qlen)
+				devdbg (dev, "rxqlen %d --> %d",
+						temp, dev->rxq.qlen);
+			if (dev->rxq.qlen < RX_QLEN)
+				tasklet_schedule (&dev->bh);
+		}
+		if (dev->txq.qlen < TX_QLEN)
+			netif_wake_queue (&dev->net);
+	}
+}
+
+
+
+/*-------------------------------------------------------------------------
+ *
+ * USB Device Driver support
+ *
+ *-------------------------------------------------------------------------*/
+ 
+// precondition: never called in_interrupt
+
+static void usbnet_disconnect (struct usb_device *udev, void *ptr)
+{
+	struct usbnet	*dev = (struct usbnet *) ptr;
+
+	devinfo (dev, "unregister usbnet %03d/%03d, %s",
+		udev->bus->busnum, udev->devnum,
+		dev->driver_info->description);
+	
+	unregister_netdev (&dev->net);
+
+	mutex_lock (&usbnet_mutex);
+	mutex_lock (&dev->mutex);
+	list_del (&dev->dev_list);
+	mutex_unlock (&usbnet_mutex);
+
+	kfree (dev);
+	usb_dec_dev_use (udev);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+// precondition: never called in_interrupt
+
+static void *
+usbnet_probe (struct usb_device *udev, unsigned ifnum,
+			const struct usb_device_id *prod)
+{
+	struct usbnet			*dev;
+	struct net_device 		*net;
+	struct usb_interface_descriptor	*interface;
+	struct driver_info		*info;
+	int				altnum = 0;
+
+	info = (struct driver_info *) prod->driver_info;
+
+	// sanity check; expect dedicated interface/devices for now.
+	interface = &udev->actconfig->interface [ifnum].altsetting [altnum];
+	if (udev->descriptor.bNumConfigurations != 1
+			|| udev->config[0].bNumInterfaces != 1
+//			|| interface->bInterfaceClass != USB_CLASS_VENDOR_SPEC
+			) {
+		dbg ("Bogus config info");
+		return 0;
+	}
+
+	if (usb_set_interface (udev, ifnum, altnum) < 0) {
+		err ("set_interface failed");
+		return 0;
+	}
+
+	// set up our own records
+	if (!(dev = kmalloc (sizeof *dev, GFP_KERNEL))) {
+		dbg ("can't kmalloc dev");
+		return 0;
+	}
+	memset (dev, 0, sizeof *dev);
+
+	init_MUTEX_LOCKED (&dev->mutex);
+	usb_inc_dev_use (udev);
+	dev->udev = udev;
+	dev->driver_info = info;
+	INIT_LIST_HEAD (&dev->dev_list);
+	skb_queue_head_init (&dev->rxq);
+	skb_queue_head_init (&dev->txq);
+	skb_queue_head_init (&dev->done);
+	dev->bh.func = usbnet_bh;
+	dev->bh.data = (unsigned long) dev;
+
+	// set up network interface records
+	net = &dev->net;
+	SET_MODULE_OWNER (net);
+	net->priv = dev;
+	strcpy (net->name, "usb%d");
+	memcpy (net->dev_addr, node_id, sizeof node_id);
+
+	// point-to-point link ... we always use Ethernet headers 
+	// supports win32 interop and the bridge driver.
+	ether_setup (net);
+
+	net->change_mtu = usbnet_change_mtu;
+	net->get_stats = usbnet_get_stats;
+	net->hard_start_xmit = usbnet_start_xmit;
+	net->open = usbnet_open;
+	net->stop = usbnet_stop;
+	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
+	net->tx_timeout = usbnet_tx_timeout;
+
+	register_netdev (&dev->net);
+	devinfo (dev, "register usbnet %03d/%03d, %s",
+		udev->bus->busnum, udev->devnum,
+		dev->driver_info->description);
+
+	// ok, it's ready to go.
+	mutex_lock (&usbnet_mutex);
+	list_add (&dev->dev_list, &usbnet_list);
+	mutex_unlock (&dev->mutex);
+
+	// start as if the link is up
+	netif_device_attach (&dev->net);
+
+	mutex_unlock (&usbnet_mutex);
+	return dev;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * chip vendor names won't normally be on the cables, and
+ * may not be on the device.
+ */
+
+static const struct usb_device_id	products [] = {
+
+#ifdef	CONFIG_USB_AN2720
+{
+	USB_DEVICE (0x0547, 0x2720),	// AnchorChips defaults
+	driver_info:	(unsigned long) &an2720_info,
+},
+#endif
+
+
+// GeneSys GL620USB (www.genesyslogic.com.tw)
+// (patch exists against an older driver version)
+
+
+#ifdef	CONFIG_USB_LINUXDEV
+/*
+ * for example, this can be a host side talk-to-PDA driver.
+ * this driver is NOT what runs _inside_ a Linux device !!
+ */
+{
+	// 1183 = 0x049F, both used as hex values?
+	USB_DEVICE (0x049F, 0x505A),	// Compaq "Itsy"
+	driver_info:	(unsigned long) &linuxdev_info,
+},
+#endif
+
+#ifdef	CONFIG_USB_NET1080
+{
+	USB_DEVICE (0x0525, 0x1080),	// NetChip ref design
+	driver_info:	(unsigned long) &net1080_info,
+},
+#endif
+
+#ifdef	CONFIG_USB_BELKIN_F5U104
+{
+	USB_DEVICE (0x050d, 0x0004),	// Belkin
+	driver_info:	(unsigned long) &belkin_info,
+}, {
+	USB_DEVICE (0x056c, 0x8100),	// eTEK
+	driver_info:	(unsigned long) &belkin_info,
+},
+#endif
+
+#ifdef CONFIG_USB_PL2301
+{
+	USB_DEVICE (0x067b, 0x0000),	// PL-2301
+	driver_info:	(unsigned long) &prolific_info,
+}, {
+	USB_DEVICE (0x067b, 0x0001),	// PL-2302
+	driver_info:	(unsigned long) &prolific_info,
+},
+#endif
+
+	{ },		// END
+};
+MODULE_DEVICE_TABLE (usb, products);
+
+static struct usb_driver usbnet_driver = {
+	name:		"usbnet",
+	id_table:	products,
+	probe:		usbnet_probe,
+	disconnect:	usbnet_disconnect,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int __init usbnet_init (void)
+{
+	// compiler should optimize this out
+	if (sizeof (((struct sk_buff *)0)->cb) < sizeof (struct skb_data))
+		BUG ();
+
+	get_random_bytes (node_id, sizeof node_id);
+	node_id [0] &= 0xfe;	// clear multicast bit
+
+ 	if (usb_register (&usbnet_driver) < 0)
+ 		return -1;
+
+	return 0;
+}
+module_init (usbnet_init);
+
+static void __exit usbnet_exit (void)
+{
+ 	usb_deregister (&usbnet_driver);
+}
+module_exit (usbnet_exit);
+
+MODULE_AUTHOR ("David Brownell <dbrownell@users.sourceforge.net>");
+MODULE_DESCRIPTION ("USB Host-to-Host Link Drivers (Belkin, Linux, NetChip, Prolific, ...)");
+MODULE_LICENSE("GPL");

FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)