Date:	Fri, 24 Apr 2009 17:31:10 +0200
From:	Omar Laazimani <omar.oberthur@...il.com>
To:	netdev@...r.kernel.org
Cc:	david-b@...bell.net
Subject: [PATCH] : CDC EEM driver patch to be applied to 2.6.30 kernel

This patch introduces a CDC EEM kernel module (host side only) to
supports USB EEM devices.


diff -ruN linux-source-2.6.30/drivers/net/usb/cdc_eem.c
linux-source-2.6.30_new/drivers/net/usb/cdc_eem.c
--- linux-source-2.6.30/drivers/net/usb/cdc_eem.c	1970-01-01
01:00:00.000000000 +0100
+++ linux-source-2.6.30_new/drivers/net/usb/cdc_eem.c	2009-04-24
13:27:30.000000000 +0200
@@ -0,0 +1,254 @@
+/*
+ * USB CDC EEM based networking peripherals
+ * Copyright (C) 2009 Oberthur Technologies by Omar Laazimani,
Olivier Condemine
+ *
+ * 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
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/ctype.h>
+#include <linux/ethtool.h>
+#include <linux/workqueue.h>
+#include <linux/mii.h>
+#include <linux/usb.h>
+#include <linux/crc32.h>
+#include <linux/usb/cdc.h>
+#include <linux/usb/usbnet.h>
+
+/*
+ * This module encapsulates Ethernet frames for transport
+ * across the USB bus, normally "usb0".
+ *
+ * This driver is a first implementation for CDC EEM specification.
+ * For more details, see www.usb.org/developers/devclass_docs/CDC_EEM10.pdf
+ *
+ * This driver implements only the USB Packet with single EEM payload case.
+ * This version has been tested with GIGAntIC WuaoW SIM Smart Card on 2.6.24,
+ * 2.6.27 and 2.6.30rc2 kernel.
+ * It has also been validated on Openmoko Om 2008.12 (based on 2.6.24 kernel).
+ * v1.0 build on 23-April-2009
+ */
+
+
+#define EEM_HEAD  2       /* 2 byte header */
+#define EEM_TAIL  4       /* 4 byte crc tail */
+
+#define EEM_MAX_PACKET	(ETH_FRAME_LEN + EEM_HEAD + EEM_TAIL)
+
+/*-------------------------------------------------------------------------*/
+
+static int eem_bind(struct usbnet *dev, struct usb_interface *intf)
+{
+	int status = 0;
+
+	status = usbnet_get_endpoints(dev, intf);
+	if (status < 0) {
+		usb_set_intfdata(intf, NULL);
+		usb_driver_release_interface(driver_of(intf), intf);
+		return status;
+	}
+
+	return 0;
+}
+
+void eem_unbind(struct usbnet *dev, struct usb_interface *intf)
+{
+	struct cdc_state	*info = (void *) &dev->data;
+	struct usb_driver	*driver = driver_of(intf);
+
+	if (intf == info->control && info->data) {
+		usb_set_intfdata(info->data, NULL);
+		usb_driver_release_interface(driver, info->data);
+		info->data = NULL;
+	}
+
+	else if (intf == info->data && info->control) {
+		usb_set_intfdata(info->control, NULL);
+		usb_driver_release_interface(driver, info->control);
+		info->control = NULL;
+	}
+}
+
+
+static struct sk_buff *eem_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
+				       gfp_t flags)
+{
+	struct sk_buff	*skb2 = NULL;
+	int		len = skb->len;
+	u32		crc = 0;
+
+	/* EEM packet format:
+	 * b0: 		bmType
+	 * b1: 		bmCRC
+	 * b2..b15:	length of ethernet frame
+	 * b16..n-4: 	ethernet frame data
+	 * bn-3..n: 	CRC
+	 */
+
+	if (!skb_cloned(skb)) {
+		int	headroom = skb_headroom(skb);
+		int	tailroom = skb_tailroom(skb);
+
+		if ((tailroom >= EEM_TAIL) && (headroom >= EEM_HEAD))
+			goto done;
+
+		if ((headroom + tailroom) > (EEM_TAIL + EEM_HEAD)) {
+			skb->data = memmove(skb->head +
+					EEM_HEAD,
+					skb->data,
+					skb->len);
+			skb_set_tail_pointer(skb, len);
+			goto done;
+		}
+	}
+
+	skb2 = skb_copy_expand(skb, EEM_HEAD, EEM_TAIL, flags);
+	if (!skb2)
+		return NULL;
+
+	dev_kfree_skb_any(skb);
+	skb = skb2;
+
+done:
+	crc = crc32_le(~0, skb->data, skb->len);
+	crc = ~crc;
+
+	*skb_put(skb, 1) = crc & 0xff;
+	*skb_put(skb, 1) = (crc >> 8) & 0xff;
+	*skb_put(skb, 1) = (crc >> 16) & 0xff;
+	*skb_put(skb, 1) = (crc >> 24) & 0xff;
+
+	len = skb->len;
+
+	*skb_push(skb, 1) = (len >> 8) | 0x40;
+	*skb_push(skb, 1) = len;
+
+	return skb;
+}
+
+static int eem_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
+{
+	u16 	*header = NULL;
+	u32 	*tailer = NULL;
+	bool	bmType, bmCRC;
+
+	/*
+	 * EEM packet format:
+	 * b0: 		bmType
+	 * b1: 		bmCRC
+	 * b2..b15:	length of ethernet frame
+	 * b16..n-4: 	ethernet frame data
+	 * bn-3..n: 	CRC
+	 */
+	header = (u16 *) skb->data;
+	skb_pull(skb, EEM_HEAD);
+
+	/*
+	 * The bmType bit helps to denote when EEM
+	 * packet is data or command :
+	 *	bmType = 0	: EEM data payload
+	 *	bmType = 1	: EEM command
+	 */
+	if (*header >> 15)
+		bmType = true;
+	else
+		bmType = false;
+
+	/*
+	 * The bmCRC helps to denote when the CRC
+	 * field contains a calculated CRC :
+	 *	bmCRC = 1	: CRC is calculated
+	 *	bmCRC = 0	: CRC = "0xDEADBEAF"
+	 */
+	if ((*header >> 14) & 0x01)
+		bmCRC = true;
+	else
+		bmCRC = false;
+
+	tailer = (u32 *) (skb->data + skb->len - sizeof(u32));
+	skb_trim(skb, skb->len - EEM_TAIL);
+
+	if (bmCRC) {
+		/* FIXME This version of cdc_eem is a little bit tolerant :
+		 * this case is considered like DEADBEAF mode.
+		 */
+	} else {
+		if (*tailer != 0xefbeadde) {
+			dbg("bad CRC");
+			return 0;
+		}
+	}
+
+	if (bmType) {
+		/* FIXME the EEM commands are not managed yet. */
+		return 0;
+	}
+
+	return 1;
+}
+
+static const struct driver_info	eem_info = {
+	.description =	"EEM Device",
+	.flags =	FLAG_ETHER,
+	.bind =		eem_bind,
+	.unbind =	eem_unbind,
+	.rx_fixup = 	eem_rx_fixup,
+	.tx_fixup =	eem_tx_fixup,
+};
+
+/*-------------------------------------------------------------------------*/
+
+
+static const struct usb_device_id products[] = {
+/*
+ * CDC EEM interface.
+ */
+{
+	USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_EEM,
+			USB_CDC_PROTO_EEM),
+	.driver_info = (unsigned long) &eem_info,
+},
+	{ },
+};
+MODULE_DEVICE_TABLE(usb, products);
+
+static struct usb_driver eem_driver = {
+	.name =		"cdc_eem",
+	.id_table =	products,
+	.probe =	usbnet_probe,
+	.disconnect =	usbnet_disconnect,
+	.suspend =	usbnet_suspend,
+	.resume =	usbnet_resume,
+};
+
+
+static int __init eem_init(void)
+{
+	return usb_register(&eem_driver);
+}
+module_init(eem_init);
+
+static void __exit eem_exit(void)
+{
+	usb_deregister(&eem_driver);
+}
+module_exit(eem_exit);
+
+MODULE_AUTHOR("Omar Laazimani <omar.oberthur at gmail.com>");
+MODULE_DESCRIPTION("USB CDC EEM v1.0");
+MODULE_LICENSE("GPL");
diff -ruN linux-source-2.6.30/drivers/net/usb/Kconfig
linux-source-2.6.30_new/drivers/net/usb/Kconfig
--- linux-source-2.6.30/drivers/net/usb/Kconfig	2009-03-24
10:59:19.000000000 +0100
+++ linux-source-2.6.30_new/drivers/net/usb/Kconfig	2009-04-23
16:50:08.000000000 +0200
@@ -180,6 +180,21 @@
 	  IEEE 802 "local assignment" bit is set in the address, a "usbX"
 	  name is used instead.

+config USB_NET_CDCEEM
+	tristate "CDC EEM support (smart devices such as usb smart card)"
+	depends on USB_USBNET
+	default m
+	help
+	  This option supports devices conforming to the Communication Device
+	  Class (CDC) Ethernet Emulation Model, a specification that's easy to
+	  implement in device firmware.  The CDC EEM specifications are available
+	  from <http://www.usb.org/>.
+
+	  This driver creates an interface named "ethX", where X depends on
+	  what other networking devices you have in use.  However, if the
+	  IEEE 802 "local assignment" bit is set in the address, a "usbX"
+	  name is used instead.
+
 config USB_NET_DM9601
 	tristate "Davicom DM9601 based USB 1.1 10/100 ethernet devices"
 	depends on USB_USBNET
diff -ruN linux-source-2.6.30/drivers/net/usb/Makefile
linux-source-2.6.30_new/drivers/net/usb/Makefile
--- linux-source-2.6.30/drivers/net/usb/Makefile	2009-03-24
10:59:19.000000000 +0100
+++ linux-source-2.6.30_new/drivers/net/usb/Makefile	2009-04-23
16:49:22.000000000 +0200
@@ -9,6 +9,7 @@
 obj-$(CONFIG_USB_HSO)		+= hso.o
 obj-$(CONFIG_USB_NET_AX8817X)	+= asix.o
 obj-$(CONFIG_USB_NET_CDCETHER)	+= cdc_ether.o
+obj-$(CONFIG_USB_NET_CDCEEM)	+= cdc_eem.o
 obj-$(CONFIG_USB_NET_DM9601)	+= dm9601.o
 obj-$(CONFIG_USB_NET_SMSC95XX)	+= smsc95xx.o
 obj-$(CONFIG_USB_NET_GL620A)	+= gl620a.o
diff -ruN linux-source-2.6.30/include/linux/usb/cdc.h
linux-source-2.6.30_new/include/linux/usb/cdc.h
--- linux-source-2.6.30/include/linux/usb/cdc.h	2009-04-15
15:17:52.000000000 +0200
+++ linux-source-2.6.30_new/include/linux/usb/cdc.h	2009-04-17
11:11:52.000000000 +0200
@@ -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
+
 /*-------------------------------------------------------------------------*/

 /*
Signed-off-by: Omar Laazimani <omar.oberthur@...il.com>
--
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