Subject: USB: usbnet (1/9) clean up framing

From: David Brownell <[email-masked]>
Date: Wed, 31 Aug 2005 09:52:31 -0700

This starts to prepare the core of "usbnet" to know less about various
framing protocols that map Ethernet packets onto USB, so "minidrivers"
can be modules that just plug into the core.

  - Remove some framing-specific code that cluttered the core:

      * net->hard_header_len records how much space to preallocate;
        now drivers that add their own framing (Net1080, GeneLink,
	Zaurus, and RNDIS) will have smoother TX paths.  Even for
	the drivers (Zaurus, Net1080) that need trailers.

      * defines new dev->hard_mtu, using this "hardware" limit to
        check changes to the link's settable "software" mtu.

      * now net->hard_header_len and dev->hard_mtu are set up in the
        driver bind() routines, if needed.

  - Transaction ID is no longer specific to the Net1080 framing;
    RNDIS needs one too.

  - Creates a new "usbnet.h" header with declarations that are shared
    between the core and what will be separate modules.

  - Plus a couple other minor tweaks, like recognizing -ESHUTDOWN
    means the keventd work should just shut itself down asap.

The core code is only about 1/3 of this large file.  Splitting out the
minidrivers into separate modules (e.g. ones for ASIX adapters,
Zaurii and similar, CDC Ethernet, etc), in later patches, will
improve maintainability and shrink typical runtime footprints.

Signed-off-by: David Brownell <[email-masked]>
Signed-off-by: Greg Kroah-Hartman <[email-masked]>

---
 drivers/usb/net/Kconfig  |    1 
 drivers/usb/net/usbnet.c |  289 ++++++++++++++---------------------------------
 drivers/usb/net/usbnet.h |  150 ++++++++++++++++++++++++
 3 files changed, 240 insertions(+), 200 deletions(-)

--- gregkh-2.6.orig/drivers/usb/net/Kconfig	2005-09-08 14:08:26.000000000 -0700
+++ gregkh-2.6/drivers/usb/net/Kconfig	2005-09-08 14:08:35.000000000 -0700
@@ -247,6 +247,7 @@ config USB_CDCETHER
 	  
 	  CDC Ethernet is an implementation option for DOCSIS cable modems
 	  that support USB connectivity, used for non-Microsoft USB hosts.
+	  The Linux-USB CDC Ethernet Gadget driver is an open implementation.
  	  This driver should work with at least the following devices:
 
  	    * Ericsson PipeRider (all variants)
--- gregkh-2.6.orig/drivers/usb/net/usbnet.c	2005-09-08 14:08:26.000000000 -0700
+++ gregkh-2.6/drivers/usb/net/usbnet.c	2005-09-08 14:08:35.000000000 -0700
@@ -1,6 +1,6 @@
 /*
  * USB Networking Links
- * Copyright (C) 2000-2005 by David Brownell <[email-masked]>
+ * Copyright (C) 2000-2005 by David Brownell
  * Copyright (C) 2002 Pavel Machek <[email-masked]>
  * Copyright (C) 2003-2005 David Hollis <[email-masked]>
  * Copyright (C) 2005 Phil Chang <[email-masked]>
@@ -126,19 +126,18 @@
 #include <linux/init.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
-#include <linux/random.h>
 #include <linux/ethtool.h>
 #include <linux/workqueue.h>
 #include <linux/mii.h>
-#include <asm/uaccess.h>
-#include <asm/unaligned.h>
 #include <linux/usb.h>
-#include <asm/io.h>
-#include <asm/scatterlist.h>
 #include <linux/mm.h>
 #include <linux/dma-mapping.h>
 
-#define DRIVER_VERSION		"03-Nov-2004"
+#include <asm/unaligned.h>
+
+#include "usbnet.h"
+
+#define DRIVER_VERSION		"22-Aug-2005"

 /*-------------------------------------------------------------------------*/
@@ -149,14 +148,16 @@
  * One maximum size Ethernet packet takes twenty four of them.
  * For high speed, each frame comfortably fits almost 36 max size
  * Ethernet packets (so queues should be bigger).
+ *
+ * REVISIT qlens should be members of 'struct usbnet'; the goal is to
+ * let the USB host controller be busy for 5msec or more before an irq
+ * is required, under load.  Jumbograms change the equation.
  */
 #define	RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? 60 : 4)
 #define	TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? 60 : 4)
 
-// packets are always ethernet inside
-// ... except they can be bigger (limit of 64K with NetChip framing)
+/* packets are always ethernet, sometimes wrapped in other 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)
@@ -166,7 +167,7 @@
 #define THROTTLE_JIFFIES	(HZ/8)
 
 // for vendor-specific control operations
-#define	CONTROL_TIMEOUT_MS	500
+#define	CONTROL_TIMEOUT_MS	USB_CTRL_GET_TIMEOUT
 
 // between wakeups
 #define UNLINK_TIMEOUT_MS	3
@@ -176,109 +177,6 @@
 // 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;
-	wait_queue_head_t	*wait;
-
-	// i/o info: pipes etc
-	unsigned		in, out;
-	struct usb_host_endpoint *status;
-	unsigned		maxpacket;
-	struct timer_list	delay;
-
-	// protocol/interface state
-	struct net_device	*net;
-	struct net_device_stats	stats;
-	int			msg_enable;
-	unsigned long		data [5];
-
-	struct mii_if_info	mii;
-
-	// various kinds of pending driver work
-	struct sk_buff_head	rxq;
-	struct sk_buff_head	txq;
-	struct sk_buff_head	done;
-	struct urb		*interrupt;
-	struct tasklet_struct	bh;
-
-	struct work_struct	kevent;
-	unsigned long		flags;
-#		define EVENT_TX_HALT	0
-#		define EVENT_RX_HALT	1
-#		define EVENT_RX_MEMORY	2
-#		define EVENT_STS_SPLIT	3
-#		define EVENT_LINK_RESET	4
-};
-
-// device-specific info used by the driver
-struct driver_info {
-	char		*description;
-
-	int		flags;
-/* framing is CDC Ethernet, not writing ZLPs (hw issues), or optionally: */
-#define FLAG_FRAMING_NC	0x0001		/* guard against device dropouts */ 
-#define FLAG_FRAMING_GL	0x0002		/* genelink batches packets */
-#define FLAG_FRAMING_Z	0x0004		/* zaurus adds a trailer */
-#define FLAG_FRAMING_RN	0x0008		/* RNDIS batches, plus huge header */
-
-#define FLAG_NO_SETINT	0x0010		/* device can't set_interface() */
-#define FLAG_ETHER	0x0020		/* maybe use "eth%d" names */
-
-#define FLAG_FRAMING_AX 0x0040          /* AX88772/178 packets */
-
-	/* init device ... can sleep, or cause probe() failure */
-	int	(*bind)(struct usbnet *, struct usb_interface *);
-
-	/* cleanup device ... can sleep, but can't fail */
-	void	(*unbind)(struct usbnet *, struct usb_interface *);
-
-	/* reset device ... can sleep */
-	int	(*reset)(struct usbnet *);
-
-	/* see if peer is connected ... can sleep */
-	int	(*check_connect)(struct usbnet *);
-
-	/* for status polling */
-	void	(*status)(struct usbnet *, struct urb *);
-
-	/* link reset handling, called from defer_kevent */
-	int	(*link_reset)(struct usbnet *);
-
-	/* fixup rx packet (strip framing) */
-	int	(*rx_fixup)(struct usbnet *dev, struct sk_buff *skb);
-
-	/* fixup tx packet (add framing) */
-	struct sk_buff	*(*tx_fixup)(struct usbnet *dev,
-				struct sk_buff *skb, unsigned flags);
-
-	// FIXME -- also an interrupt mechanism
-	// useful for at least PL2301/2302 and GL620USB-A
-	// and CDC use them to report 'is it connected' changes
-
-	/* for new devices, use the descriptor-reading code instead */
-	int		in;		/* rx endpoint */
-	int		out;		/* tx endpoint */
-
-	unsigned long	data;		/* Misc driver specific data */
-};
-
-// 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;
-};
-
 static const char driver_name [] = "usbnet";
 
 /* use ethtool to change the level for any given device */
@@ -286,22 +184,6 @@ static int msg_level = -1;
 module_param (msg_level, int, 0);
 MODULE_PARM_DESC (msg_level, "Override default message level");
 
-
-#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 deverr(usbnet, fmt, arg...) \
-	printk(KERN_ERR "%s: " fmt "\n" , (usbnet)->net->name , ## arg)
-#define devwarn(usbnet, fmt, arg...) \
-	printk(KERN_WARNING "%s: " fmt "\n" , (usbnet)->net->name , ## arg)
-
-#define devinfo(usbnet, fmt, arg...) \
-	printk(KERN_INFO "%s: " fmt "\n" , (usbnet)->net->name , ## arg); \
-
 /*-------------------------------------------------------------------------*/
 
 static void usbnet_get_drvinfo (struct net_device *, struct ethtool_drvinfo *);
@@ -921,6 +803,11 @@ static int ax8817x_bind(struct usbnet *d
 		ADVERTISE_ALL | ADVERTISE_CSMA | ADVERTISE_PAUSE_CAP);
 	mii_nway_restart(&dev->mii);
 
+	if (dev->driver_info->flags & FLAG_FRAMING_AX) {
+		/* REVISIT:  adjust hard_header_len too */
+		dev->hard_mtu = 2048;
+	}
+
 	return 0;
 out2:
 	kfree(buf);
@@ -1432,9 +1319,8 @@ static int generic_cdc_bind (struct usbn
 					info->ether->bLength);
 				goto bad_desc;
 			}
-			dev->net->mtu = le16_to_cpup (
-						&info->ether->wMaxSegmentSize)
-					- ETH_HLEN;
+			dev->hard_mtu = le16_to_cpu(
+						info->ether->wMaxSegmentSize);
 			/* because of Zaurus, we may be ignoring the host
 			 * side link address we were given.
 			 */
@@ -1988,9 +1874,17 @@ genelink_tx_fixup (struct usbnet *dev, s
 	return skb;
 }
 
+static int genelink_bind (struct usbnet *dev, struct usb_interface *intf)
+{
+	dev->hard_mtu = GL_RCV_BUF_SIZE;
+	dev->net->hard_header_len += 4;
+	return 0;
+}
+
 static const struct driver_info	genelink_info = {
 	.description =	"Genesys GeneLink",
 	.flags =	FLAG_FRAMING_GL | FLAG_NO_SETINT,
+	.bind =		genelink_bind,
 	.rx_fixup =	genelink_rx_fixup,
 	.tx_fixup =	genelink_tx_fixup,
 
@@ -2015,7 +1909,6 @@ static const struct driver_info	genelink
  *
  *-------------------------------------------------------------------------*/
 
-#define dev_packet_id	data[0]
 #define frame_errors	data[1]
 
 /*
@@ -2057,6 +1950,9 @@ struct nc_trailer {
 
 #define MIN_FRAMED	FRAMED_SIZE(0)
 
+/* packets _could_ be up to 64KB... */
+#define NC_MAX_PACKET	32767
+
 
 /*
  * Zero means no timeout; else, how long a 64 byte bulk packet may be queued
@@ -2398,16 +2294,14 @@ static void nc_ensure_sync (struct usbne
 static int net1080_rx_fixup (struct usbnet *dev, struct sk_buff *skb)
 {
 	struct nc_header	*header;
+	struct net_device	*net = dev->net;
 	struct nc_trailer	*trailer;
 	u16			hdr_len, packet_len;
 
-	if (!(skb->len & 0x01)
-			|| MIN_FRAMED > skb->len
-			|| skb->len > FRAMED_SIZE (dev->net->mtu)) {
+	if (!(skb->len & 0x01)) {
 		dev->stats.rx_frame_errors++;
 		dbg ("rx framesize %d range %d..%d mtu %d", skb->len,
-			(int)MIN_FRAMED, (int)FRAMED_SIZE (dev->net->mtu),
-			dev->net->mtu);
+			net->hard_header_len, dev->hard_mtu, net->mtu);
 		nc_ensure_sync (dev);
 		return 0;
 	}
@@ -2415,7 +2309,7 @@ static int net1080_rx_fixup (struct usbn
 	header = (struct nc_header *) skb->data;
 	hdr_len = le16_to_cpup (&header->hdr_len);
 	packet_len = le16_to_cpup (&header->packet_len);
-	if (FRAMED_SIZE (packet_len) > MAX_PACKET) {
+	if (FRAMED_SIZE (packet_len) > NC_MAX_PACKET) {
 		dev->stats.rx_frame_errors++;
 		dbg ("packet too big, %d", packet_len);
 		nc_ensure_sync (dev);
@@ -2505,11 +2399,23 @@ net1080_tx_fixup (struct usbnet *dev, st
 	return skb2;
 }
 
+static int net1080_bind (struct usbnet *dev, struct usb_interface *intf)
+{
+	unsigned	extra = sizeof (struct nc_header)
+				+ 1
+				+ sizeof (struct nc_trailer);
+
+	dev->net->hard_header_len += extra;
+	dev->hard_mtu = NC_MAX_PACKET;
+	return 0;
+}
+
 static const struct driver_info	net1080_info = {
 	.description =	"NetChip TurboCONNECT",
 	.flags =	FLAG_FRAMING_NC,
+	.bind =		net1080_bind,
 	.reset =	net1080_reset,
-	.check_connect =net1080_check_connect,
+	.check_connect = net1080_check_connect,
 	.rx_fixup =	net1080_rx_fixup,
 	.tx_fixup =	net1080_tx_fixup,
 };
@@ -2690,11 +2596,20 @@ done:
 	return skb;
 }
 
+static int zaurus_bind (struct usbnet *dev, struct usb_interface *intf)
+{
+	/* Belcarra's funky framing has other options; mostly
+	 * TRAILERS (!) with 4 bytes CRC, and maybe 2 pad bytes.
+	 */
+	dev->net->hard_header_len += 6;
+	return generic_cdc_bind(dev, intf);
+}
+
 static const struct driver_info	zaurus_sl5x00_info = {
 	.description =	"Sharp Zaurus SL-5x00",
 	.flags =	FLAG_FRAMING_Z,
 	.check_connect = always_connected,
-	.bind =		generic_cdc_bind,
+	.bind =		zaurus_bind,
 	.unbind =	cdc_unbind,
 	.tx_fixup = 	zaurus_tx_fixup,
 };
@@ -2704,7 +2619,7 @@ static const struct driver_info	zaurus_p
 	.description =	"Sharp Zaurus, PXA-2xx based",
 	.flags =	FLAG_FRAMING_Z,
 	.check_connect = always_connected,
-	.bind =		generic_cdc_bind,
+	.bind =		zaurus_bind,
 	.unbind =	cdc_unbind,
 	.tx_fixup = 	zaurus_tx_fixup,
 };
@@ -2714,7 +2629,7 @@ static const struct driver_info	olympus_
 	.description =	"Olympus R1000",
 	.flags =	FLAG_FRAMING_Z,
 	.check_connect = always_connected,
-	.bind =		generic_cdc_bind,
+	.bind =		zaurus_bind,
 	.unbind =	cdc_unbind,
 	.tx_fixup = 	zaurus_tx_fixup,
 };
@@ -2868,22 +2783,12 @@ static const struct driver_info	bogus_md
 static int usbnet_change_mtu (struct net_device *net, int new_mtu)
 {
 	struct usbnet	*dev = netdev_priv(net);
+	int		ll_mtu = new_mtu + net->hard_header_len;
 
-	if (new_mtu <= MIN_PACKET || new_mtu > MAX_PACKET)
+	if (new_mtu <= 0 || ll_mtu > dev->hard_mtu)
 		return -EINVAL;
-#ifdef	CONFIG_USB_NET1080
-	if (((dev->driver_info->flags) & FLAG_FRAMING_NC)) {
-		if (FRAMED_SIZE (new_mtu) > MAX_PACKET)
-			return -EINVAL;
-	}
-#endif
-#ifdef	CONFIG_USB_GENESYS
-	if (((dev->driver_info->flags) & FLAG_FRAMING_GL)
-			&& new_mtu > GL_MAX_PACKET_LEN)
-		return -EINVAL;
-#endif
 	// no second zero-length packet read wanted after mtu-sized packets
-	if (((new_mtu + sizeof (struct ethhdr)) % dev->maxpacket) == 0)
+	if ((ll_mtu % dev->maxpacket) == 0)
 		return -EDOM;
 	net->mtu = new_mtu;
 	return 0;
@@ -2943,33 +2848,8 @@ static void rx_submit (struct usbnet *de
 	unsigned long		lockflags;
 	size_t			size;
 
-#ifdef CONFIG_USB_NET1080
-	if (dev->driver_info->flags & FLAG_FRAMING_NC)
-		size = FRAMED_SIZE (dev->net->mtu);
-	else
-#endif
-#ifdef CONFIG_USB_GENESYS
-	if (dev->driver_info->flags & FLAG_FRAMING_GL)
-		size = GL_RCV_BUF_SIZE;
-	else
-#endif
-#ifdef CONFIG_USB_ZAURUS
-	if (dev->driver_info->flags & FLAG_FRAMING_Z)
-		size = 6 + (sizeof (struct ethhdr) + dev->net->mtu);
-	else
-#endif
-#ifdef CONFIG_USB_RNDIS
-	if (dev->driver_info->flags & FLAG_FRAMING_RN)
-		size = RNDIS_MAX_TRANSFER;
-	else
-#endif
-#ifdef CONFIG_USB_AX8817X
-	if (dev->driver_info->flags & FLAG_FRAMING_AX)
-		size = 2048;
-	else
-#endif
-		size = (sizeof (struct ethhdr) + dev->net->mtu);
-
+	size = max(dev->net->hard_header_len + dev->net->mtu,
+			(unsigned)ETH_FRAME_LEN);
 	if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
 		if (netif_msg_rx_err (dev))
 			devdbg (dev, "no rx skb");
@@ -3062,7 +2942,7 @@ static void rx_complete (struct urb *urb
 	switch (urb_status) {
 	    // success
 	    case 0:
-		if (MIN_PACKET > skb->len || skb->len > MAX_PACKET) {
+		if (skb->len < dev->net->hard_header_len) {
 			entry->state = rx_cleanup;
 			dev->stats.rx_errors++;
 			dev->stats.rx_length_errors++;
@@ -3334,11 +3214,11 @@ static u32 usbnet_get_link (struct net_d
 {
 	struct usbnet *dev = netdev_priv(net);
 
-	/* If a check_connect is defined, return it's results */
+	/* If a check_connect is defined, return its result */
 	if (dev->driver_info->check_connect)
 		return dev->driver_info->check_connect (dev) == 0;
 
-	/* Otherwise, we're up to avoid breaking scripts */
+	/* Otherwise, say we're up (to avoid breaking scripts) */
 	return 1;
 }
 
@@ -3386,19 +3266,24 @@ kevent (void *data)
 	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
 		unlink_urbs (dev, &dev->txq);
 		status = usb_clear_halt (dev->udev, dev->out);
-		if (status < 0 && status != -EPIPE) {
+		if (status < 0
+				&& status != -EPIPE
+				&& status != -ESHUTDOWN) {
 			if (netif_msg_tx_err (dev))
 				deverr (dev, "can't clear tx halt, status %d",
 					status);
 		} else {
 			clear_bit (EVENT_TX_HALT, &dev->flags);
-			netif_wake_queue (dev->net);
+			if (status != -ESHUTDOWN)
+				netif_wake_queue (dev->net);
 		}
 	}
 	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
 		unlink_urbs (dev, &dev->rxq);
 		status = usb_clear_halt (dev->udev, dev->in);
-		if (status < 0 && status != -EPIPE) {
+		if (status < 0
+				&& status != -EPIPE
+				&& status != -ESHUTDOWN) {
 			if (netif_msg_rx_err (dev))
 				deverr (dev, "can't clear rx halt, status %d",
 					status);
@@ -3574,7 +3459,7 @@ static int usbnet_start_xmit (struct sk_
 
 #ifdef	CONFIG_USB_NET1080
 	if (info->flags & FLAG_FRAMING_NC) {
-		header->packet_id = cpu_to_le16 ((u16)dev->dev_packet_id++);
+		header->packet_id = cpu_to_le16 ((u16)dev->xid++);
 		put_unaligned (header->packet_id, &trailer->packet_id);
 #if 0
 		devdbg (dev, "frame >tx h %d p %d id %d",
@@ -3776,6 +3661,7 @@ usbnet_probe (struct usb_interface *udev
 	dev->net = net;
 	strcpy (net->name, "usb%d");
 	memcpy (net->dev_addr, node_id, sizeof node_id);
+	dev->hard_mtu = net->mtu + net->hard_header_len;
 
 #if 0
 // dma_supported() is deeply broken on almost all architectures
@@ -3804,6 +3690,10 @@ usbnet_probe (struct usb_interface *udev
 		if ((dev->driver_info->flags & FLAG_ETHER) != 0
 				&& (net->dev_addr [0] & 0x02) == 0)
 			strcpy (net->name, "eth%d");
+
+		/* maybe the remote can't receive an Ethernet MTU */
+		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
+			net->mtu = dev->hard_mtu - net->hard_header_len;
 	} else if (!info->in || info->out)
 		status = get_endpoints (dev, udev);
 	else {
@@ -3817,7 +3707,6 @@ usbnet_probe (struct usb_interface *udev
 			status = 0;
 
 	}
-
 	if (status == 0 && dev->status)
 		status = init_status (dev, udev);
 	if (status < 0)
@@ -4212,7 +4101,7 @@ static struct ethtool_ops usbnet_ethtool
 
 /*-------------------------------------------------------------------------*/
 
-static int __init usbnet_init (void)
+static int __init usbnet_init(void)
 {
 	// compiler should optimize these out
 	BUG_ON (sizeof (((struct sk_buff *)0)->cb)
@@ -4226,14 +4115,14 @@ static int __init usbnet_init (void)
 
  	return usb_register(&usbnet_driver);
 }
-module_init (usbnet_init);
+module_init(usbnet_init);
 
-static void __exit usbnet_exit (void)
+static void __exit usbnet_exit(void)
 {
- 	usb_deregister (&usbnet_driver);
+ 	usb_deregister(&usbnet_driver);
 }
-module_exit (usbnet_exit);
+module_exit(usbnet_exit);
 
-MODULE_AUTHOR ("David Brownell <[email-masked]>");
-MODULE_DESCRIPTION ("USB Host-to-Host Link Drivers (numerous vendors)");
-MODULE_LICENSE ("GPL");
+MODULE_AUTHOR("David Brownell");
+MODULE_DESCRIPTION("USB Host-to-Host Link Drivers (numerous vendors)");
+MODULE_LICENSE("GPL");
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gregkh-2.6/drivers/usb/net/usbnet.h	2005-09-08 14:08:35.000000000 -0700
@@ -0,0 +1,150 @@
+/*
+ * USB Networking Link Interface
+ *
+ * Copyright (C) 2000-2005 by David Brownell <[email-masked]>
+ * Copyright (C) 2003-2005 David Hollis <[email-masked]>
+ *
+ * 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
+ */
+
+
+#ifndef	__USBNET_H
+#define	__USBNET_H
+
+
+/* interface from usbnet core to each USB networking device we handle */
+struct usbnet {
+	/* housekeeping */
+	struct usb_device	*udev;
+	struct driver_info	*driver_info;
+	wait_queue_head_t	*wait;
+
+	/* i/o info: pipes etc */
+	unsigned		in, out;
+	struct usb_host_endpoint *status;
+	unsigned		maxpacket;
+	struct timer_list	delay;
+
+	/* protocol/interface state */
+	struct net_device	*net;
+	struct net_device_stats	stats;
+	int			msg_enable;
+	unsigned long		data [5];
+	u32			xid;
+	u32			hard_mtu;	/* count any extra framing */
+	struct mii_if_info	mii;
+
+	/* various kinds of pending driver work */
+	struct sk_buff_head	rxq;
+	struct sk_buff_head	txq;
+	struct sk_buff_head	done;
+	struct urb		*interrupt;
+	struct tasklet_struct	bh;
+
+	struct work_struct	kevent;
+	unsigned long		flags;
+#		define EVENT_TX_HALT	0
+#		define EVENT_RX_HALT	1
+#		define EVENT_RX_MEMORY	2
+#		define EVENT_STS_SPLIT	3
+#		define EVENT_LINK_RESET	4
+};
+
+
+/* interface from the device/framing level "minidriver" to core */
+struct driver_info {
+	char		*description;
+
+	int		flags;
+/* framing is CDC Ethernet, not writing ZLPs (hw issues), or optionally: */
+#define FLAG_FRAMING_NC	0x0001		/* guard against device dropouts */
+#define FLAG_FRAMING_GL	0x0002		/* genelink batches packets */
+#define FLAG_FRAMING_Z	0x0004		/* zaurus adds a trailer */
+#define FLAG_FRAMING_RN	0x0008		/* RNDIS batches, plus huge header */
+
+#define FLAG_NO_SETINT	0x0010		/* device can't set_interface() */
+#define FLAG_ETHER	0x0020		/* maybe use "eth%d" names */
+
+#define FLAG_FRAMING_AX 0x0040          /* AX88772/178 packets */
+
+	/* init device ... can sleep, or cause probe() failure */
+	int	(*bind)(struct usbnet *, struct usb_interface *);
+
+	/* cleanup device ... can sleep, but can't fail */
+	void	(*unbind)(struct usbnet *, struct usb_interface *);
+
+	/* reset device ... can sleep */
+	int	(*reset)(struct usbnet *);
+
+	/* see if peer is connected ... can sleep */
+	int	(*check_connect)(struct usbnet *);
+
+	/* for status polling */
+	void	(*status)(struct usbnet *, struct urb *);
+
+	/* link reset handling, called from defer_kevent */
+	int	(*link_reset)(struct usbnet *);
+
+	/* fixup rx packet (strip framing) */
+	int	(*rx_fixup)(struct usbnet *dev, struct sk_buff *skb);
+
+	/* fixup tx packet (add framing) */
+	struct sk_buff	*(*tx_fixup)(struct usbnet *dev,
+				struct sk_buff *skb, unsigned flags);
+
+	/* for new devices, use the descriptor-reading code instead */
+	int		in;		/* rx endpoint */
+	int		out;		/* tx endpoint */
+
+	unsigned long	data;		/* Misc driver specific data */
+};
+
+
+/* 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;
+};
+
+
+
+/* messaging support includes the interface name, so it must not be
+ * used before it has one ... notably, in minidriver bind() calls.
+ */
+#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 deverr(usbnet, fmt, arg...) \
+	printk(KERN_ERR "%s: " fmt "\n" , (usbnet)->net->name , ## arg)
+#define devwarn(usbnet, fmt, arg...) \
+	printk(KERN_WARNING "%s: " fmt "\n" , (usbnet)->net->name , ## arg)
+
+#define devinfo(usbnet, fmt, arg...) \
+	printk(KERN_INFO "%s: " fmt "\n" , (usbnet)->net->name , ## arg); \
+
+
+#endif	/* __USBNET_H */