[PATCH] USB: usbnet (1/9) clean up framing

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 <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/net/Kconfig

@@ -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)

drivers/usb/net/usbnet.h

+/*
+ * USB Networking Link Interface
+ *
+ * Copyright (C) 2000-2005 by David Brownell <dbrownell@users.sourceforge.net>
+ * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.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; 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 */