usbnet: CDC EEM support (v5)

This introduces a CDC Ethernet Emulation Model (EEM) host side
driver to support USB EEM devices.

EEM is different from the Ethernet Control Model (ECM) currently
supported by the "CDC Ethernet" driver.  One key difference is
that it doesn't require of USB interface alternate settings to
manage interface state; some maldesigned hardware can't handle
that part of USB.  It also avoids a separate USB interface for
control and status updates.

[ dbrownell@users.sourceforge.net: fix skb leaks, add rx packet
checks, improve fault handling, EEM conformance updates, cleanup ]

Signed-off-by: Omar Laazimani <omar.oberthur@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/usb/cdc.h b/include/linux/usb/cdc.h
index 3c86ed25a04c..c24124a42ce5 100644
--- a/include/linux/usb/cdc.h
+++ b/include/linux/usb/cdc.h
@@ -17,6 +17,7 @@
 #define USB_CDC_SUBCLASS_DMM                    0x09
 #define USB_CDC_SUBCLASS_MDLM                   0x0a
 #define USB_CDC_SUBCLASS_OBEX                   0x0b
+#define USB_CDC_SUBCLASS_EEM                    0x0c
 
 #define USB_CDC_PROTO_NONE                      0
 
@@ -28,6 +29,8 @@
 #define USB_CDC_ACM_PROTO_AT_CDMA               6
 #define USB_CDC_ACM_PROTO_VENDOR                0xff
 
+#define USB_CDC_PROTO_EEM                       7
+
 /*-------------------------------------------------------------------------*/
 
 /*