Message-ID: <3a98b4410904280747x55be4a51y8043f827b93d0a80@mail.gmail.com>
Date:	Tue, 28 Apr 2009 16:47:34 +0200
From:	Omar Laazimani <omar.oberthur@...il.com>
To:	netdev@...r.kernel.org
Cc:	david-b@...bell.net, David Miller <davem@...emloft.net>
Subject: Re: [PATCH] : CDC EEM driver patch to be applied to 2.6.30 kernel

This is version 4 of the patch which introduces a CDC EEM kernel module
(host side only) to supports USB EEM devices. This version fixes a
small bug in "USB Packet with
EEM bundle" case.

Signed-off-by: Omar Laazimani <omar.oberthur <at> gmail.com>

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	2009-04-28
16:29:12.000000000 +0200
@@ -0,0 +1,312 @@
+/*
+ * 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.
+ *
+ * This driver is a first implementation for CDC EEM specification.
+ * For more details, see www.usb.org/developers/devclass_docs/CDC_EEM10.pdf
+ *
+ * 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).
+ * 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 void eem_transmit_complete(struct urb *urb)
+{
+	kfree(urb->context);
+	usb_free_urb(urb);
+}
+
+static void eem_transmit(struct usbnet *dev, struct sk_buff *skb)
+{
+	struct urb		*urb;
+	int			status;
+	struct skb_data		*entry;
+	int			length;
+
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if (!urb)
+		return;
+
+	length = skb->len;
+
+	entry = (struct skb_data *) skb->cb;
+	entry->urb = urb;
+	entry->dev = dev;
+	entry->length = length;
+
+	usb_fill_bulk_urb(urb, dev->udev, dev->out,
+			skb->data, skb->len, eem_transmit_complete, skb);
+
+	status = usb_submit_urb(urb, GFP_ATOMIC);
+	if (status) {
+		usb_free_urb(urb);
+		return;
+	}
+}
+
+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;
+	u16		len = skb->len;
+	u32		crc = 0;
+
+	/* EEM packet header format:
+	 * b0..13:	length of ethernet frame
+	 * b14:		bmCRC
+	 * b15:		bmType
+	 */
+	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;
+
+	put_unaligned_le32(crc, skb_put(skb, 4));
+
+	len = skb->len;
+	put_unaligned_le16(BIT(14) | len, skb_push(skb, 2));
+
+	return skb;
+}
+
+static int eem_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
+{
+	struct sk_buff	*skb2 = NULL;
+	u32 		crc;
+	u16		len, header;
+	u16 		bmEEMCmd;
+
+	do {
+		/*
+		 * EEM packet header format:
+		 * b0..14:	EEM type dependant (Data or Command)
+		 * b15:		bmType
+		 */
+		header = get_unaligned_le16(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 & BIT(15)) {
+			/*
+			 * EEM command packet:
+			 * b0..10:	bmEEMCmdParam
+			 * b11..13:	bmEEMCmd
+			 * b14:		bmReserved (0 by default)
+			 * b15:		1
+			 */
+
+			skb2 = skb_clone(skb, GFP_ATOMIC);
+			if (unlikely(!skb2))
+				goto Continue;
+
+			bmEEMCmd = (BIT(11) & header)
+				| (BIT(12) & header)
+				| (BIT(13) & header);
+
+			/*
+			 * Only answer to Echo command. Host may
+			 * choose to ignore other commands (see CDC EEM spec.)
+			 */
+			if (bmEEMCmd == 0) { /* Echo command */
+				len = header & 0x7FF;
+				skb_trim(skb2, len);
+				put_unaligned_le16(BIT(15) | BIT(11) | len
+						, skb_push(skb2, 2));
+				eem_transmit(dev, skb2);
+			} else
+				len = 0; /* length of other commands */
+
+		} else {
+			/*
+			 * EEM data packet header :
+			 * b0..13:	length of ethernet frame
+			 * b14:		bmCRC
+			 * b15:		0
+			 */
+			len = header & 0x3FFF;
+
+			skb2 = skb_clone(skb, GFP_ATOMIC);
+			if (unlikely(!skb2))
+				goto Continue;
+
+			crc = get_unaligned_le32(skb2->data + len - EEM_TAIL);
+			skb_trim(skb2, len - EEM_TAIL);
+
+			/*
+			 * The bmCRC helps to denote when the CRC
+			 * field contains a calculated CRC :
+			 *	bmCRC = 1	: CRC is calculated
+			 *	bmCRC = 0	: CRC = 0xDEADBEEF
+			 */
+			if (header & BIT(14)) {
+				u32 crc2;
+				crc2 = crc32_le(~0, skb2->data, len);
+				crc2 = ~crc2;
+				if (unlikely(crc != crc2)) {
+					dev->stats.rx_errors++;
+					goto Continue;
+				}
+			} else {
+				if (unlikely(crc != 0xdeadbeef)) {
+					dev->stats.rx_errors++;
+					goto Continue;
+				}
+			}
+
+			usbnet_skb_return(dev, skb2);
+		}
+Continue:
+		skb_pull(skb, len);
+	} while (skb->len);
+
+	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[] = {
+{
+	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");
+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	2009-04-27
17:51:10.000000000 +0200
@@ -180,6 +180,20 @@
 	  IEEE 802 "local assignment" bit is set in the address, a "usbX"
 	  name is used instead.

+config USB_NET_CDC_EEM
+	tristate "CDC EEM support"
+	depends on USB_USBNET && EXPERIMENTAL
+	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	2009-04-27
17:48:27.000000000 +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_CDC_EEM)	+= 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
+
 /*-------------------------------------------------------------------------*/

 /*
--
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