[PATCH] USB: usbnet (2/9) module for simple network links

This patch creates the first of several separate "minidriver" modules
for "usbnet".  This one handles only the very simplest hardware, which
can be handled almost entirely by the "usbnet" core.

    - Move device-specific bits into new "cdc_subset.c" driver,
      shrinking "usbnet" by a bunch;

    - Export the functions needed to support this minidriver
      (with EXPORT_SYMBOL_GPL);

    - Update Kconfig and kbuild accordingly.

This one handles about a dozen different device types, with the most
notable ones being Gumstix and most Linux-based PDAs (except Zaurus
running that ancient code from Sharp).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/net/Kconfig

@@ -128,32 +128,6 @@ config USB_USBNET
 comment "USB Host-to-Host Cables"
 	depends on USB_USBNET
 
-config USB_ALI_M5632
-	boolean "ALi M5632 based 'USB 2.0 Data Link' cables"
-	depends on USB_USBNET
-	default y
-	help
-	  Choose this option if you're using a host-to-host cable
-	  based on this design, which supports USB 2.0 high speed.
-
-config USB_AN2720
-	boolean "AnchorChips 2720 based cables (Xircom PGUNET, ...)"
-	depends on USB_USBNET
-	default y
-	help
-	  Choose this option if you're using a host-to-host cable
-	  based on this design.  Note that AnchorChips is now a
-	  Cypress brand.
-
-config USB_BELKIN
-	boolean "eTEK based host-to-host cables (Advance, Belkin, ...)"
-	depends on USB_USBNET
-	default y
-	help
-	  Choose this option if you're using a host-to-host cable
-	  based on this design:  two NetChip 2890 chips and an Atmel
-	  microcontroller, with LEDs that indicate traffic.
-
 config USB_GENESYS
 	boolean "GeneSys GL620USB-A based cables"
 	default y
@@ -182,42 +156,9 @@ config USB_PL2301
 	  Choose this option if you're using a host-to-host cable
 	  with one of these chips.
 
-config USB_KC2190
-	boolean "KT Technology KC2190 based cables (InstaNet)"
-	default y
-	depends on USB_USBNET && EXPERIMENTAL
-	help
-	  Choose this option if you're using a host-to-host cable
-	  with one of these chips.
-
 comment "Intelligent USB Devices/Gadgets"
 	depends on USB_USBNET
 
-config USB_ARMLINUX
-	boolean "Embedded ARM Linux links (iPaq, ...)"
-	depends on USB_USBNET
-	default y
-	help
-	  Choose this option to support the "usb-eth" networking driver
-	  used by most of the ARM Linux community with device controllers
-	  such as the SA-11x0 and PXA-25x UDCs, or the tftp capabilities
-	  in some PXA versions of the "blob" boot loader.
-
-	  Linux-based "Gumstix" PXA-25x based systems use this protocol
-	  to talk with other Linux systems.
-
-	  Although the ROMs shipped with Sharp Zaurus products use a
-	  different link level framing protocol, you can have them use
-	  this simpler protocol by installing a different kernel.
-
-config USB_EPSON2888
-	boolean "Epson 2888 based firmware (DEVELOPMENT)"
-	depends on USB_USBNET
-	default y
-	help
-	  Choose this option to support the usb networking links used
-	  by some sample firmware from Epson.
-
 config USB_ZAURUS
 	boolean "Sharp Zaurus (stock ROMs) and compatible"
 	depends on USB_USBNET
@@ -292,6 +233,70 @@ config USB_AX8817X
 	  This driver creates an interface named "ethX", where X depends on
 	  what other networking devices you have in use.  
 
+
+config USB_NET_CDC_SUBSET
+	tristate "Simple USB Network Links (CDC Ethernet subset)"
+	depends on USB_USBNET
+	help
+	  This driver module supports USB network devices that can work
+	  without any device-specific information.  Select it if you have
+	  one of these drivers.
+
+	  Note that while many USB host-to-host cables can work in this mode,
+	  that may mean not being able to talk to Win32 systems or more
+	  commonly not being able to handle certain events (like replugging
+	  the host on the other end) very well.  Also, these devices will
+	  not generally have permanently assigned Ethernet addresses.
+
+config USB_ALI_M5632
+	boolean "ALi M5632 based 'USB 2.0 Data Link' cables"
+	depends on USB_NET_CDC_SUBSET
+	help
+	  Choose this option if you're using a host-to-host cable
+	  based on this design, which supports USB 2.0 high speed.
+
+config USB_AN2720
+	boolean "AnchorChips 2720 based cables (Xircom PGUNET, ...)"
+	depends on USB_NET_CDC_SUBSET
+	help
+	  Choose this option if you're using a host-to-host cable
+	  based on this design.  Note that AnchorChips is now a
+	  Cypress brand.
+
+config USB_BELKIN
+	boolean "eTEK based host-to-host cables (Advance, Belkin, ...)"
+	depends on USB_NET_CDC_SUBSET
+	default y
+	help
+	  Choose this option if you're using a host-to-host cable
+	  based on this design:  two NetChip 2890 chips and an Atmel
+	  microcontroller, with LEDs that indicate traffic.
+
+config USB_ARMLINUX
+	boolean "Embedded ARM Linux links (iPaq, ...)"
+	depends on USB_NET_CDC_SUBSET
+	default y
+	help
+	  Choose this option to support the "usb-eth" networking driver
+	  used by most of the ARM Linux community with device controllers
+	  such as the SA-11x0 and PXA-25x UDCs, or the tftp capabilities
+	  in some PXA versions of the "blob" boot loader.
+
+	  Linux-based "Gumstix" PXA-25x based systems use this protocol
+	  to talk with other Linux systems.
+
+	  Although the ROMs shipped with Sharp Zaurus products use a
+	  different link level framing protocol, you can have them use
+	  this simpler protocol by installing a different kernel.
+
+config USB_EPSON2888
+	boolean "Epson 2888 based firmware (DEVELOPMENT)"
+	depends on USB_NET_CDC_SUBSET
+	help
+	  Choose this option to support the usb networking links used
+	  by some sample firmware from Epson.
+
+
 config USB_ZD1201
 	tristate "USB ZD1201 based Wireless device support"
 	depends on NET_RADIO

drivers/usb/net/Makefile

@@ -6,5 +6,6 @@ obj-$(CONFIG_USB_CATC)		+= catc.o
 obj-$(CONFIG_USB_KAWETH)	+= kaweth.o
 obj-$(CONFIG_USB_PEGASUS)	+= pegasus.o
 obj-$(CONFIG_USB_RTL8150)	+= rtl8150.o
+obj-$(CONFIG_USB_NET_CDC_SUBSET)	+= cdc_subset.o
 obj-$(CONFIG_USB_USBNET)	+= usbnet.o
 obj-$(CONFIG_USB_ZD1201)	+= zd1201.o

drivers/usb/net/usbnet.h

@@ -24,7 +24,7 @@
 #define	__USBNET_H
 
 
-/* interface from usbnet core to each USB networking device we handle */
+/* interface from usbnet core to each USB networking link we handle */
 struct usbnet {
 	/* housekeeping */
 	struct usb_device	*udev;
@@ -62,6 +62,10 @@ struct usbnet {
 #		define EVENT_LINK_RESET	4
 };
 
+static inline struct usb_driver *driver_of(struct usb_interface *intf)
+{
+	return to_usb_driver(intf->dev.driver);
+}
 
 /* interface from the device/framing level "minidriver" to core */
 struct driver_info {
@@ -111,6 +115,15 @@ struct driver_info {
 	unsigned long	data;		/* Misc driver specific data */
 };
 
+/* Minidrivers are just drivers using the "usbnet" core as a powerful
+ * network-specific subroutine library ... that happens to do pretty
+ * much everything except custom framing and chip-specific stuff.
+ */
+extern int usbnet_probe(struct usb_interface *, const struct usb_device_id *);
+extern int usbnet_suspend (struct usb_interface *, pm_message_t );
+extern int usbnet_resume (struct usb_interface *);
+extern void usbnet_disconnect(struct usb_interface *);
+
 
 /* we record the state for each of our queued skbs */
 enum skb_state {