[ncm] Add support for CDC-NCM USB Ethernet devices

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/ecm.c

@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2014 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <errno.h>
+#include <ipxe/if_ether.h>
+#include <ipxe/base16.h>
+#include <ipxe/usb.h>
+#include "ecm.h"
+
+/** @file
+ *
+ * CDC-ECM USB Ethernet driver
+ *
+ */
+
+/**
+ * Locate Ethernet functional descriptor
+ *
+ * @v config		Configuration descriptor
+ * @v interface		Interface descriptor
+ * @ret desc		Descriptor, or NULL if not found
+ */
+struct ecm_ethernet_descriptor *
+ecm_ethernet_descriptor ( struct usb_configuration_descriptor *config,
+			  struct usb_interface_descriptor *interface ) {
+	struct ecm_ethernet_descriptor *desc;
+
+	for_each_interface_descriptor ( desc, config, interface ) {
+		if ( ( desc->header.type == USB_CS_INTERFACE_DESCRIPTOR ) &&
+		     ( desc->subtype == CDC_SUBTYPE_ETHERNET ) )
+			return desc;
+	}
+	return NULL;
+}
+
+/**
+ * Get hardware MAC address
+ *
+ * @v usb		USB device
+ * @v desc		Ethernet functional descriptor
+ * @v hw_addr		Hardware address to fill in
+ * @ret rc		Return status code
+ */
+int ecm_fetch_mac ( struct usb_device *usb,
+		    struct ecm_ethernet_descriptor *desc, uint8_t *hw_addr ) {
+	char buf[ base16_encoded_len ( ETH_ALEN ) + 1 /* NUL */ ];
+	int len;
+	int rc;
+
+	/* Fetch MAC address string */
+	len = usb_get_string_descriptor ( usb, desc->mac, 0, buf,
+					  sizeof ( buf ) );
+	if ( len < 0 ) {
+		rc = len;
+		return rc;
+	}
+
+	/* Sanity check */
+	if ( len != ( ( int ) ( sizeof ( buf ) - 1 /* NUL */ ) ) )
+		return -EINVAL;
+
+	/* Decode MAC address */
+	len = base16_decode ( buf, hw_addr );
+	if ( len < 0 ) {
+		rc = len;
+		return rc;
+	}
+
+	return 0;
+}

src/drivers/net/ecm.h

@@ -0,0 +1,40 @@
+#ifndef _ECM_H
+#define _ECM_H
+
+/** @file
+ *
+ * CDC-ECM USB Ethernet driver
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <ipxe/usb.h>
+#include <ipxe/cdc.h>
+
+/** An Ethernet Functional Descriptor */
+struct ecm_ethernet_descriptor {
+	/** Descriptor header */
+	struct usb_descriptor_header header;
+	/** Descriptor subtype */
+	uint8_t subtype;
+	/** MAC addres string */
+	uint8_t mac;
+	/** Ethernet statistics bitmap */
+	uint32_t statistics;
+	/** Maximum segment size */
+	uint16_t mtu;
+	/** Multicast filter configuration */
+	uint16_t mcast;
+	/** Number of wake-on-LAN filters */
+	uint8_t wol;
+} __attribute__ (( packed ));
+
+extern struct ecm_ethernet_descriptor *
+ecm_ethernet_descriptor ( struct usb_configuration_descriptor *config,
+			  struct usb_interface_descriptor *interface );
+extern int ecm_fetch_mac ( struct usb_device *usb,
+			   struct ecm_ethernet_descriptor *desc,
+			   uint8_t *hw_addr );
+
+#endif /* _ECM_H */