can: kvaser_usb: Add support for Kvaser CAN/USB devices

This driver provides support for several Kvaser CAN/USB devices.
Such kind of devices supports up to three CAN network interfaces.

It has been tested with a Kvaser USB Leaf Light (one network interface)
connected to a pch_can interface.
The firmware version of the Kvaser device was 2.5.205.

List of Kvaser devices supported by the driver:
  - Kvaser Leaf Light
  - Kvaser Leaf Professional HS
  - Kvaser Leaf SemiPro HS
  - Kvaser Leaf Professional LS
  - Kvaser Leaf Professional SWC
  - Kvaser Leaf Professional LIN
  - Kvaser Leaf SemiPro LS
  - Kvaser Leaf SemiPro SWC
  - Kvaser Memorator II HS/HS
  - Kvaser USBcan Professional HS/HS
  - Kvaser Leaf Light GI
  - Kvaser Leaf Professional HS (OBD-II connector)
  - Kvaser Memorator Professional HS/LS
  - Kvaser Leaf Light "China"
  - Kvaser BlackBird SemiPro
  - Kvaser USBcan R

Signed-off-by: Daniel Berglund <db@kvaser.com>
Signed-off-by: Olivier Sobrie <olivier@sobrie.be>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/usb/Kconfig

@@ -13,6 +13,35 @@ config CAN_ESD_USB2
           This driver supports the CAN-USB/2 interface
           from esd electronic system design gmbh (http://www.esd.eu).
 
+config CAN_KVASER_USB
+	tristate "Kvaser CAN/USB interface"
+	---help---
+	  This driver adds support for Kvaser CAN/USB devices like Kvaser
+	  Leaf Light.
+
+	  The driver gives support for the following devices:
+	    - Kvaser Leaf Light
+	    - Kvaser Leaf Professional HS
+	    - Kvaser Leaf SemiPro HS
+	    - Kvaser Leaf Professional LS
+	    - Kvaser Leaf Professional SWC
+	    - Kvaser Leaf Professional LIN
+	    - Kvaser Leaf SemiPro LS
+	    - Kvaser Leaf SemiPro SWC
+	    - Kvaser Memorator II HS/HS
+	    - Kvaser USBcan Professional HS/HS
+	    - Kvaser Leaf Light GI
+	    - Kvaser Leaf Professional HS (OBD-II connector)
+	    - Kvaser Memorator Professional HS/LS
+	    - Kvaser Leaf Light "China"
+	    - Kvaser BlackBird SemiPro
+	    - Kvaser USBcan R
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called kvaser_usb.
+
 config CAN_PEAK_USB
 	tristate "PEAK PCAN-USB/USB Pro interfaces"
 	---help---

drivers/net/can/usb/Makefile

@@ -4,6 +4,7 @@
 
 obj-$(CONFIG_CAN_EMS_USB) += ems_usb.o
 obj-$(CONFIG_CAN_ESD_USB2) += esd_usb2.o
+obj-$(CONFIG_CAN_KVASER_USB) += kvaser_usb.o
 obj-$(CONFIG_CAN_PEAK_USB) += peak_usb/
 
 ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG

drivers/net/can/usb/kvaser_usb.c

@@ -0,0 +1,1627 @@
+/*
+ * 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 version 2.
+ *
+ * Parts of this driver are based on the following:
+ *  - Kvaser linux leaf driver (version 4.78)
+ *  - CAN driver for esd CAN-USB/2
+ *
+ * Copyright (C) 2002-2006 KVASER AB, Sweden. All rights reserved.
+ * Copyright (C) 2010 Matthias Fuchs <matthias.fuchs@esd.eu>, esd gmbh
+ * Copyright (C) 2012 Olivier Sobrie <olivier@sobrie.be>
+ */
+
+#include <linux/init.h>
+#include <linux/completion.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/usb.h>
+
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+
+#define MAX_TX_URBS			16
+#define MAX_RX_URBS			4
+#define START_TIMEOUT			1000 /* msecs */
+#define STOP_TIMEOUT			1000 /* msecs */
+#define USB_SEND_TIMEOUT		1000 /* msecs */
+#define USB_RECV_TIMEOUT		1000 /* msecs */
+#define RX_BUFFER_SIZE			3072
+#define CAN_USB_CLOCK			8000000
+#define MAX_NET_DEVICES			3
+
+/* Kvaser USB devices */
+#define KVASER_VENDOR_ID		0x0bfd
+#define USB_LEAF_DEVEL_PRODUCT_ID	10
+#define USB_LEAF_LITE_PRODUCT_ID	11
+#define USB_LEAF_PRO_PRODUCT_ID		12
+#define USB_LEAF_SPRO_PRODUCT_ID	14
+#define USB_LEAF_PRO_LS_PRODUCT_ID	15
+#define USB_LEAF_PRO_SWC_PRODUCT_ID	16
+#define USB_LEAF_PRO_LIN_PRODUCT_ID	17
+#define USB_LEAF_SPRO_LS_PRODUCT_ID	18
+#define USB_LEAF_SPRO_SWC_PRODUCT_ID	19
+#define USB_MEMO2_DEVEL_PRODUCT_ID	22
+#define USB_MEMO2_HSHS_PRODUCT_ID	23
+#define USB_UPRO_HSHS_PRODUCT_ID	24
+#define USB_LEAF_LITE_GI_PRODUCT_ID	25
+#define USB_LEAF_PRO_OBDII_PRODUCT_ID	26
+#define USB_MEMO2_HSLS_PRODUCT_ID	27
+#define USB_LEAF_LITE_CH_PRODUCT_ID	28
+#define USB_BLACKBIRD_SPRO_PRODUCT_ID	29
+#define USB_OEM_MERCURY_PRODUCT_ID	34
+#define USB_OEM_LEAF_PRODUCT_ID		35
+#define USB_CAN_R_PRODUCT_ID		39
+
+/* USB devices features */
+#define KVASER_HAS_SILENT_MODE		BIT(0)
+#define KVASER_HAS_TXRX_ERRORS		BIT(1)
+
+/* Message header size */
+#define MSG_HEADER_LEN			2
+
+/* Can message flags */
+#define MSG_FLAG_ERROR_FRAME		BIT(0)
+#define MSG_FLAG_OVERRUN		BIT(1)
+#define MSG_FLAG_NERR			BIT(2)
+#define MSG_FLAG_WAKEUP			BIT(3)
+#define MSG_FLAG_REMOTE_FRAME		BIT(4)
+#define MSG_FLAG_RESERVED		BIT(5)
+#define MSG_FLAG_TX_ACK			BIT(6)
+#define MSG_FLAG_TX_REQUEST		BIT(7)
+
+/* Can states */
+#define M16C_STATE_BUS_RESET		BIT(0)
+#define M16C_STATE_BUS_ERROR		BIT(4)
+#define M16C_STATE_BUS_PASSIVE		BIT(5)
+#define M16C_STATE_BUS_OFF		BIT(6)
+
+/* Can msg ids */
+#define CMD_RX_STD_MESSAGE		12
+#define CMD_TX_STD_MESSAGE		13
+#define CMD_RX_EXT_MESSAGE		14
+#define CMD_TX_EXT_MESSAGE		15
+#define CMD_SET_BUS_PARAMS		16
+#define CMD_GET_BUS_PARAMS		17
+#define CMD_GET_BUS_PARAMS_REPLY	18
+#define CMD_GET_CHIP_STATE		19
+#define CMD_CHIP_STATE_EVENT		20
+#define CMD_SET_CTRL_MODE		21
+#define CMD_GET_CTRL_MODE		22
+#define CMD_GET_CTRL_MODE_REPLY		23
+#define CMD_RESET_CHIP			24
+#define CMD_RESET_CARD			25
+#define CMD_START_CHIP			26
+#define CMD_START_CHIP_REPLY		27
+#define CMD_STOP_CHIP			28
+#define CMD_STOP_CHIP_REPLY		29
+#define CMD_GET_CARD_INFO2		32
+#define CMD_GET_CARD_INFO		34
+#define CMD_GET_CARD_INFO_REPLY		35
+#define CMD_GET_SOFTWARE_INFO		38
+#define CMD_GET_SOFTWARE_INFO_REPLY	39
+#define CMD_ERROR_EVENT			45
+#define CMD_FLUSH_QUEUE			48
+#define CMD_RESET_ERROR_COUNTER		49
+#define CMD_TX_ACKNOWLEDGE		50
+#define CMD_CAN_ERROR_EVENT		51
+#define CMD_USB_THROTTLE		77
+#define CMD_LOG_MESSAGE			106
+
+/* error factors */
+#define M16C_EF_ACKE			BIT(0)
+#define M16C_EF_CRCE			BIT(1)
+#define M16C_EF_FORME			BIT(2)
+#define M16C_EF_STFE			BIT(3)
+#define M16C_EF_BITE0			BIT(4)
+#define M16C_EF_BITE1			BIT(5)
+#define M16C_EF_RCVE			BIT(6)
+#define M16C_EF_TRE			BIT(7)
+
+/* bittiming parameters */
+#define KVASER_USB_TSEG1_MIN		1
+#define KVASER_USB_TSEG1_MAX		16
+#define KVASER_USB_TSEG2_MIN		1
+#define KVASER_USB_TSEG2_MAX		8
+#define KVASER_USB_SJW_MAX		4
+#define KVASER_USB_BRP_MIN		1
+#define KVASER_USB_BRP_MAX		64
+#define KVASER_USB_BRP_INC		1
+
+/* ctrl modes */
+#define KVASER_CTRL_MODE_NORMAL		1
+#define KVASER_CTRL_MODE_SILENT		2
+#define KVASER_CTRL_MODE_SELFRECEPTION	3
+#define KVASER_CTRL_MODE_OFF		4
+
+struct kvaser_msg_simple {
+	u8 tid;
+	u8 channel;
+} __packed;
+
+struct kvaser_msg_cardinfo {
+	u8 tid;
+	u8 nchannels;
+	__le32 serial_number;
+	__le32 padding;
+	__le32 clock_resolution;
+	__le32 mfgdate;
+	u8 ean[8];
+	u8 hw_revision;
+	u8 usb_hs_mode;
+	__le16 padding2;
+} __packed;
+
+struct kvaser_msg_cardinfo2 {
+	u8 tid;
+	u8 channel;
+	u8 pcb_id[24];
+	__le32 oem_unlock_code;
+} __packed;
+
+struct kvaser_msg_softinfo {
+	u8 tid;
+	u8 channel;
+	__le32 sw_options;
+	__le32 fw_version;
+	__le16 max_outstanding_tx;
+	__le16 padding[9];
+} __packed;
+
+struct kvaser_msg_busparams {
+	u8 tid;
+	u8 channel;
+	__le32 bitrate;
+	u8 tseg1;
+	u8 tseg2;
+	u8 sjw;
+	u8 no_samp;
+} __packed;
+
+struct kvaser_msg_tx_can {
+	u8 channel;
+	u8 tid;
+	u8 msg[14];
+	u8 padding;
+	u8 flags;
+} __packed;
+
+struct kvaser_msg_rx_can {
+	u8 channel;
+	u8 flag;
+	__le16 time[3];
+	u8 msg[14];
+} __packed;
+
+struct kvaser_msg_chip_state_event {
+	u8 tid;
+	u8 channel;
+	__le16 time[3];
+	u8 tx_errors_count;
+	u8 rx_errors_count;
+	u8 status;
+	u8 padding[3];
+} __packed;
+
+struct kvaser_msg_tx_acknowledge {
+	u8 channel;
+	u8 tid;
+	__le16 time[3];
+	u8 flags;
+	u8 time_offset;
+} __packed;
+
+struct kvaser_msg_error_event {
+	u8 tid;
+	u8 flags;
+	__le16 time[3];
+	u8 channel;
+	u8 padding;
+	u8 tx_errors_count;
+	u8 rx_errors_count;
+	u8 status;
+	u8 error_factor;
+} __packed;
+
+struct kvaser_msg_ctrl_mode {
+	u8 tid;
+	u8 channel;
+	u8 ctrl_mode;
+	u8 padding[3];
+} __packed;
+
+struct kvaser_msg_flush_queue {
+	u8 tid;
+	u8 channel;
+	u8 flags;
+	u8 padding[3];
+} __packed;
+
+struct kvaser_msg_log_message {
+	u8 channel;
+	u8 flags;
+	__le16 time[3];
+	u8 dlc;
+	u8 time_offset;
+	__le32 id;
+	u8 data[8];
+} __packed;
+
+struct kvaser_msg {
+	u8 len;
+	u8 id;
+	union	{
+		struct kvaser_msg_simple simple;
+		struct kvaser_msg_cardinfo cardinfo;
+		struct kvaser_msg_cardinfo2 cardinfo2;
+		struct kvaser_msg_softinfo softinfo;
+		struct kvaser_msg_busparams busparams;
+		struct kvaser_msg_tx_can tx_can;
+		struct kvaser_msg_rx_can rx_can;
+		struct kvaser_msg_chip_state_event chip_state_event;
+		struct kvaser_msg_tx_acknowledge tx_acknowledge;
+		struct kvaser_msg_error_event error_event;
+		struct kvaser_msg_ctrl_mode ctrl_mode;
+		struct kvaser_msg_flush_queue flush_queue;
+		struct kvaser_msg_log_message log_message;
+	} u;
+} __packed;
+
+struct kvaser_usb_tx_urb_context {
+	struct kvaser_usb_net_priv *priv;
+	u32 echo_index;
+	int dlc;
+};
+
+struct kvaser_usb {
+	struct usb_device *udev;
+	struct kvaser_usb_net_priv *nets[MAX_NET_DEVICES];
+
+	struct usb_endpoint_descriptor *bulk_in, *bulk_out;
+	struct usb_anchor rx_submitted;
+
+	u32 fw_version;
+	unsigned int nchannels;
+
+	bool rxinitdone;
+	void *rxbuf[MAX_RX_URBS];
+	dma_addr_t rxbuf_dma[MAX_RX_URBS];
+};
+
+struct kvaser_usb_net_priv {
+	struct can_priv can;
+
+	atomic_t active_tx_urbs;
+	struct usb_anchor tx_submitted;
+	struct kvaser_usb_tx_urb_context tx_contexts[MAX_TX_URBS];
+
+	struct completion start_comp, stop_comp;
+
+	struct kvaser_usb *dev;
+	struct net_device *netdev;
+	int channel;
+
+	struct can_berr_counter bec;
+};
+
+static const struct usb_device_id kvaser_usb_table[] = {
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_DEVEL_PRODUCT_ID) },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_LITE_PRODUCT_ID) },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_PRO_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS |
+			       KVASER_HAS_SILENT_MODE },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_SPRO_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS |
+			       KVASER_HAS_SILENT_MODE },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_PRO_LS_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS |
+			       KVASER_HAS_SILENT_MODE },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_PRO_SWC_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS |
+			       KVASER_HAS_SILENT_MODE },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_PRO_LIN_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS |
+			       KVASER_HAS_SILENT_MODE },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_SPRO_LS_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS |
+			       KVASER_HAS_SILENT_MODE },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_SPRO_SWC_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS |
+			       KVASER_HAS_SILENT_MODE },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_MEMO2_DEVEL_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS |
+			       KVASER_HAS_SILENT_MODE },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_MEMO2_HSHS_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS |
+			       KVASER_HAS_SILENT_MODE },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_UPRO_HSHS_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_LITE_GI_PRODUCT_ID) },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_PRO_OBDII_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS |
+			       KVASER_HAS_SILENT_MODE },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_MEMO2_HSLS_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_LEAF_LITE_CH_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_BLACKBIRD_SPRO_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_OEM_MERCURY_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_OEM_LEAF_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS },
+	{ USB_DEVICE(KVASER_VENDOR_ID, USB_CAN_R_PRODUCT_ID),
+		.driver_info = KVASER_HAS_TXRX_ERRORS },
+	{ }
+};
+MODULE_DEVICE_TABLE(usb, kvaser_usb_table);
+
+static inline int kvaser_usb_send_msg(const struct kvaser_usb *dev,
+				      struct kvaser_msg *msg)
+{
+	int actual_len;
+
+	return usb_bulk_msg(dev->udev,
+			    usb_sndbulkpipe(dev->udev,
+					dev->bulk_out->bEndpointAddress),
+			    msg, msg->len, &actual_len,
+			    USB_SEND_TIMEOUT);
+}
+
+static int kvaser_usb_wait_msg(const struct kvaser_usb *dev, u8 id,
+			       struct kvaser_msg *msg)
+{
+	struct kvaser_msg *tmp;
+	void *buf;
+	int actual_len;
+	int err;
+	int pos = 0;
+
+	buf = kzalloc(RX_BUFFER_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	err = usb_bulk_msg(dev->udev,
+			   usb_rcvbulkpipe(dev->udev,
+					   dev->bulk_in->bEndpointAddress),
+			   buf, RX_BUFFER_SIZE, &actual_len,
+			   USB_RECV_TIMEOUT);
+	if (err < 0)
+		goto end;
+
+	while (pos <= actual_len - MSG_HEADER_LEN) {
+		tmp = buf + pos;
+
+		if (!tmp->len)
+			break;
+
+		if (pos + tmp->len > actual_len) {
+			dev_err(dev->udev->dev.parent, "Format error\n");
+			break;
+		}
+
+		if (tmp->id == id) {
+			memcpy(msg, tmp, tmp->len);
+			goto end;
+		}
+
+		pos += tmp->len;
+	}
+
+	err = -EINVAL;
+
+end:
+	kfree(buf);
+
+	return err;
+}
+
+static int kvaser_usb_send_simple_msg(const struct kvaser_usb *dev,
+				      u8 msg_id, int channel)
+{
+	struct kvaser_msg *msg;
+	int rc;
+
+	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	msg->id = msg_id;
+	msg->len = MSG_HEADER_LEN + sizeof(struct kvaser_msg_simple);
+	msg->u.simple.channel = channel;
+	msg->u.simple.tid = 0xff;
+
+	rc = kvaser_usb_send_msg(dev, msg);
+
+	kfree(msg);
+	return rc;
+}
+
+static int kvaser_usb_get_software_info(struct kvaser_usb *dev)
+{
+	struct kvaser_msg msg;
+	int err;
+
+	err = kvaser_usb_send_simple_msg(dev, CMD_GET_SOFTWARE_INFO, 0);
+	if (err)
+		return err;
+
+	err = kvaser_usb_wait_msg(dev, CMD_GET_SOFTWARE_INFO_REPLY, &msg);
+	if (err)
+		return err;
+
+	dev->fw_version = le32_to_cpu(msg.u.softinfo.fw_version);
+
+	return 0;
+}
+
+static int kvaser_usb_get_card_info(struct kvaser_usb *dev)
+{
+	struct kvaser_msg msg;
+	int err;
+
+	err = kvaser_usb_send_simple_msg(dev, CMD_GET_CARD_INFO, 0);
+	if (err)
+		return err;
+
+	err = kvaser_usb_wait_msg(dev, CMD_GET_CARD_INFO_REPLY, &msg);
+	if (err)
+		return err;
+
+	dev->nchannels = msg.u.cardinfo.nchannels;
+
+	return 0;
+}
+
+static void kvaser_usb_tx_acknowledge(const struct kvaser_usb *dev,
+				      const struct kvaser_msg *msg)
+{
+	struct net_device_stats *stats;
+	struct kvaser_usb_tx_urb_context *context;
+	struct kvaser_usb_net_priv *priv;
+	struct sk_buff *skb;
+	struct can_frame *cf;
+	u8 channel = msg->u.tx_acknowledge.channel;
+	u8 tid = msg->u.tx_acknowledge.tid;
+
+	if (channel >= dev->nchannels) {
+		dev_err(dev->udev->dev.parent,
+			"Invalid channel number (%d)\n", channel);
+		return;
+	}
+
+	priv = dev->nets[channel];
+
+	if (!netif_device_present(priv->netdev))
+		return;
+
+	stats = &priv->netdev->stats;
+
+	context = &priv->tx_contexts[tid % MAX_TX_URBS];
+
+	/* Sometimes the state change doesn't come after a bus-off event */
+	if (priv->can.restart_ms &&
+	    (priv->can.state >= CAN_STATE_BUS_OFF)) {
+		skb = alloc_can_err_skb(priv->netdev, &cf);
+		if (skb) {
+			cf->can_id |= CAN_ERR_RESTARTED;
+			netif_rx(skb);
+
+			stats->rx_packets++;
+			stats->rx_bytes += cf->can_dlc;
+		} else {
+			netdev_err(priv->netdev,
+				   "No memory left for err_skb\n");
+		}
+
+		priv->can.can_stats.restarts++;
+		netif_carrier_on(priv->netdev);
+
+		priv->can.state = CAN_STATE_ERROR_ACTIVE;
+	}
+
+	stats->tx_packets++;
+	stats->tx_bytes += context->dlc;
+	can_get_echo_skb(priv->netdev, context->echo_index);
+
+	context->echo_index = MAX_TX_URBS;
+	atomic_dec(&priv->active_tx_urbs);
+
+	netif_wake_queue(priv->netdev);
+}
+
+static void kvaser_usb_simple_msg_callback(struct urb *urb)
+{
+	struct net_device *netdev = urb->context;
+
+	kfree(urb->transfer_buffer);
+
+	if (urb->status)
+		netdev_warn(netdev, "urb status received: %d\n",
+			    urb->status);
+}
+
+static int kvaser_usb_simple_msg_async(struct kvaser_usb_net_priv *priv,
+				       u8 msg_id)
+{
+	struct kvaser_usb *dev = priv->dev;
+	struct net_device *netdev = priv->netdev;
+	struct kvaser_msg *msg;
+	struct urb *urb;
+	void *buf;
+	int err;
+
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if (!urb) {
+		netdev_err(netdev, "No memory left for URBs\n");
+		return -ENOMEM;
+	}
+
+	buf = kmalloc(sizeof(struct kvaser_msg), GFP_ATOMIC);
+	if (!buf) {
+		netdev_err(netdev, "No memory left for USB buffer\n");
+		usb_free_urb(urb);
+		return -ENOMEM;
+	}
+
+	msg = (struct kvaser_msg *)buf;
+	msg->len = MSG_HEADER_LEN + sizeof(struct kvaser_msg_simple);
+	msg->id = msg_id;
+	msg->u.simple.channel = priv->channel;
+
+	usb_fill_bulk_urb(urb, dev->udev,
+			  usb_sndbulkpipe(dev->udev,
+					  dev->bulk_out->bEndpointAddress),
+			  buf, msg->len,
+			  kvaser_usb_simple_msg_callback, priv);
+	usb_anchor_urb(urb, &priv->tx_submitted);
+
+	err = usb_submit_urb(urb, GFP_ATOMIC);
+	if (err) {
+		netdev_err(netdev, "Error transmitting URB\n");
+		usb_unanchor_urb(urb);
+		usb_free_urb(urb);
+		kfree(buf);
+		return err;
+	}
+
+	usb_free_urb(urb);
+
+	return 0;
+}
+
+static void kvaser_usb_unlink_tx_urbs(struct kvaser_usb_net_priv *priv)
+{
+	int i;
+
+	usb_kill_anchored_urbs(&priv->tx_submitted);
+	atomic_set(&priv->active_tx_urbs, 0);
+
+	for (i = 0; i < MAX_TX_URBS; i++)
+		priv->tx_contexts[i].echo_index = MAX_TX_URBS;
+}
+
+static void kvaser_usb_rx_error(const struct kvaser_usb *dev,
+				const struct kvaser_msg *msg)
+{
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	struct net_device_stats *stats;
+	struct kvaser_usb_net_priv *priv;
+	unsigned int new_state;
+	u8 channel, status, txerr, rxerr, error_factor;
+
+	switch (msg->id) {
+	case CMD_CAN_ERROR_EVENT:
+		channel = msg->u.error_event.channel;
+		status =  msg->u.error_event.status;
+		txerr = msg->u.error_event.tx_errors_count;
+		rxerr = msg->u.error_event.rx_errors_count;
+		error_factor = msg->u.error_event.error_factor;
+		break;
+	case CMD_LOG_MESSAGE:
+		channel = msg->u.log_message.channel;
+		status = msg->u.log_message.data[0];
+		txerr = msg->u.log_message.data[2];
+		rxerr = msg->u.log_message.data[3];
+		error_factor = msg->u.log_message.data[1];
+		break;
+	case CMD_CHIP_STATE_EVENT:
+		channel = msg->u.chip_state_event.channel;
+		status =  msg->u.chip_state_event.status;
+		txerr = msg->u.chip_state_event.tx_errors_count;
+		rxerr = msg->u.chip_state_event.rx_errors_count;
+		error_factor = 0;
+		break;
+	default:
+		dev_err(dev->udev->dev.parent, "Invalid msg id (%d)\n",
+			msg->id);
+		return;
+	}
+
+	if (channel >= dev->nchannels) {
+		dev_err(dev->udev->dev.parent,
+			"Invalid channel number (%d)\n", channel);
+		return;
+	}
+
+	priv = dev->nets[channel];
+	stats = &priv->netdev->stats;
+
+	if (status & M16C_STATE_BUS_RESET) {
+		kvaser_usb_unlink_tx_urbs(priv);
+		return;
+	}
+
+	skb = alloc_can_err_skb(priv->netdev, &cf);
+	if (!skb) {
+		stats->rx_dropped++;
+		return;
+	}
+
+	new_state = priv->can.state;
+
+	netdev_dbg(priv->netdev, "Error status: 0x%02x\n", status);
+
+	if (status & M16C_STATE_BUS_OFF) {
+		cf->can_id |= CAN_ERR_BUSOFF;
+
+		priv->can.can_stats.bus_off++;
+		if (!priv->can.restart_ms)
+			kvaser_usb_simple_msg_async(priv, CMD_STOP_CHIP);
+
+		netif_carrier_off(priv->netdev);
+
+		new_state = CAN_STATE_BUS_OFF;
+	} else if (status & M16C_STATE_BUS_PASSIVE) {
+		if (priv->can.state != CAN_STATE_ERROR_PASSIVE) {
+			cf->can_id |= CAN_ERR_CRTL;
+
+			if (txerr || rxerr)
+				cf->data[1] = (txerr > rxerr)
+						? CAN_ERR_CRTL_TX_PASSIVE
+						: CAN_ERR_CRTL_RX_PASSIVE;
+			else
+				cf->data[1] = CAN_ERR_CRTL_TX_PASSIVE |
+					      CAN_ERR_CRTL_RX_PASSIVE;
+
+			priv->can.can_stats.error_passive++;
+		}
+
+		new_state = CAN_STATE_ERROR_PASSIVE;
+	}
+
+	if (status == M16C_STATE_BUS_ERROR) {
+		if ((priv->can.state < CAN_STATE_ERROR_WARNING) &&
+		    ((txerr >= 96) || (rxerr >= 96))) {
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] = (txerr > rxerr)
+					? CAN_ERR_CRTL_TX_WARNING
+					: CAN_ERR_CRTL_RX_WARNING;
+
+			priv->can.can_stats.error_warning++;
+			new_state = CAN_STATE_ERROR_WARNING;
+		} else if (priv->can.state > CAN_STATE_ERROR_ACTIVE) {
+			cf->can_id |= CAN_ERR_PROT;
+			cf->data[2] = CAN_ERR_PROT_ACTIVE;
+
+			new_state = CAN_STATE_ERROR_ACTIVE;
+		}
+	}
+
+	if (!status) {
+		cf->can_id |= CAN_ERR_PROT;
+		cf->data[2] = CAN_ERR_PROT_ACTIVE;
+
+		new_state = CAN_STATE_ERROR_ACTIVE;
+	}
+
+	if (priv->can.restart_ms &&
+	    (priv->can.state >= CAN_STATE_BUS_OFF) &&
+	    (new_state < CAN_STATE_BUS_OFF)) {
+		cf->can_id |= CAN_ERR_RESTARTED;
+		netif_carrier_on(priv->netdev);
+
+		priv->can.can_stats.restarts++;
+	}
+
+	if (error_factor) {
+		priv->can.can_stats.bus_error++;
+		stats->rx_errors++;
+
+		cf->can_id |= CAN_ERR_BUSERROR | CAN_ERR_PROT;
+
+		if (error_factor & M16C_EF_ACKE)
+			cf->data[3] |= (CAN_ERR_PROT_LOC_ACK);
+		if (error_factor & M16C_EF_CRCE)
+			cf->data[3] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
+					CAN_ERR_PROT_LOC_CRC_DEL);
+		if (error_factor & M16C_EF_FORME)
+			cf->data[2] |= CAN_ERR_PROT_FORM;
+		if (error_factor & M16C_EF_STFE)
+			cf->data[2] |= CAN_ERR_PROT_STUFF;
+		if (error_factor & M16C_EF_BITE0)
+			cf->data[2] |= CAN_ERR_PROT_BIT0;
+		if (error_factor & M16C_EF_BITE1)
+			cf->data[2] |= CAN_ERR_PROT_BIT1;
+		if (error_factor & M16C_EF_TRE)
+			cf->data[2] |= CAN_ERR_PROT_TX;
+	}
+
+	cf->data[6] = txerr;
+	cf->data[7] = rxerr;
+
+	priv->bec.txerr = txerr;
+	priv->bec.rxerr = rxerr;
+
+	priv->can.state = new_state;
+
+	netif_rx(skb);
+
+	stats->rx_packets++;
+	stats->rx_bytes += cf->can_dlc;
+}
+
+static void kvaser_usb_rx_can_err(const struct kvaser_usb_net_priv *priv,
+				  const struct kvaser_msg *msg)
+{
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	struct net_device_stats *stats = &priv->netdev->stats;
+
+	if (msg->u.rx_can.flag & (MSG_FLAG_ERROR_FRAME |
+					 MSG_FLAG_NERR)) {
+		netdev_err(priv->netdev, "Unknow error (flags: 0x%02x)\n",
+			   msg->u.rx_can.flag);
+
+		stats->rx_errors++;
+		return;
+	}
+
+	if (msg->u.rx_can.flag & MSG_FLAG_OVERRUN) {
+		skb = alloc_can_err_skb(priv->netdev, &cf);
+		if (!skb) {
+			stats->rx_dropped++;
+			return;
+		}
+
+		cf->can_id |= CAN_ERR_CRTL;
+		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+
+		stats->rx_over_errors++;
+		stats->rx_errors++;
+
+		netif_rx(skb);
+
+		stats->rx_packets++;
+		stats->rx_bytes += cf->can_dlc;
+	}
+}
+
+static void kvaser_usb_rx_can_msg(const struct kvaser_usb *dev,
+				  const struct kvaser_msg *msg)
+{
+	struct kvaser_usb_net_priv *priv;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	struct net_device_stats *stats;
+	u8 channel = msg->u.rx_can.channel;
+
+	if (channel >= dev->nchannels) {
+		dev_err(dev->udev->dev.parent,
+			"Invalid channel number (%d)\n", channel);
+		return;
+	}
+
+	priv = dev->nets[channel];
+	stats = &priv->netdev->stats;
+
+	if (msg->u.rx_can.flag & (MSG_FLAG_ERROR_FRAME | MSG_FLAG_NERR |
+				  MSG_FLAG_OVERRUN)) {
+		kvaser_usb_rx_can_err(priv, msg);
+		return;
+	} else if (msg->u.rx_can.flag & ~MSG_FLAG_REMOTE_FRAME) {
+		netdev_warn(priv->netdev,
+			    "Unhandled frame (flags: 0x%02x)",
+			    msg->u.rx_can.flag);
+		return;
+	}
+
+	skb = alloc_can_skb(priv->netdev, &cf);
+	if (!skb) {
+		stats->tx_dropped++;
+		return;
+	}
+
+	cf->can_id = ((msg->u.rx_can.msg[0] & 0x1f) << 6) |
+		     (msg->u.rx_can.msg[1] & 0x3f);
+	cf->can_dlc = get_can_dlc(msg->u.rx_can.msg[5]);
+
+	if (msg->id == CMD_RX_EXT_MESSAGE) {
+		cf->can_id <<= 18;
+		cf->can_id |= ((msg->u.rx_can.msg[2] & 0x0f) << 14) |
+			      ((msg->u.rx_can.msg[3] & 0xff) << 6) |
+			      (msg->u.rx_can.msg[4] & 0x3f);
+		cf->can_id |= CAN_EFF_FLAG;
+	}
+
+	if (msg->u.rx_can.flag & MSG_FLAG_REMOTE_FRAME)
+		cf->can_id |= CAN_RTR_FLAG;
+	else
+		memcpy(cf->data, &msg->u.rx_can.msg[6], cf->can_dlc);
+
+	netif_rx(skb);
+
+	stats->rx_packets++;
+	stats->rx_bytes += cf->can_dlc;
+}
+
+static void kvaser_usb_start_chip_reply(const struct kvaser_usb *dev,
+					const struct kvaser_msg *msg)
+{
+	struct kvaser_usb_net_priv *priv;
+	u8 channel = msg->u.simple.channel;
+
+	if (channel >= dev->nchannels) {
+		dev_err(dev->udev->dev.parent,
+			"Invalid channel number (%d)\n", channel);
+		return;
+	}
+
+	priv = dev->nets[channel];
+
+	if (completion_done(&priv->start_comp) &&
+	    netif_queue_stopped(priv->netdev)) {
+		netif_wake_queue(priv->netdev);
+	} else {
+		netif_start_queue(priv->netdev);
+		complete(&priv->start_comp);
+	}
+}
+
+static void kvaser_usb_stop_chip_reply(const struct kvaser_usb *dev,
+				       const struct kvaser_msg *msg)
+{
+	struct kvaser_usb_net_priv *priv;
+	u8 channel = msg->u.simple.channel;
+
+	if (channel >= dev->nchannels) {
+		dev_err(dev->udev->dev.parent,
+			"Invalid channel number (%d)\n", channel);
+		return;
+	}
+
+	priv = dev->nets[channel];
+
+	complete(&priv->stop_comp);
+}
+
+static void kvaser_usb_handle_message(const struct kvaser_usb *dev,
+				      const struct kvaser_msg *msg)
+{
+	switch (msg->id) {
+	case CMD_START_CHIP_REPLY:
+		kvaser_usb_start_chip_reply(dev, msg);
+		break;
+
+	case CMD_STOP_CHIP_REPLY:
+		kvaser_usb_stop_chip_reply(dev, msg);
+		break;
+
+	case CMD_RX_STD_MESSAGE:
+	case CMD_RX_EXT_MESSAGE:
+		kvaser_usb_rx_can_msg(dev, msg);
+		break;
+
+	case CMD_CHIP_STATE_EVENT:
+	case CMD_CAN_ERROR_EVENT:
+		kvaser_usb_rx_error(dev, msg);
+		break;
+
+	case CMD_LOG_MESSAGE:
+		if (msg->u.log_message.flags & MSG_FLAG_ERROR_FRAME)
+			kvaser_usb_rx_error(dev, msg);
+		break;
+
+	case CMD_TX_ACKNOWLEDGE:
+		kvaser_usb_tx_acknowledge(dev, msg);
+		break;
+
+	default:
+		dev_warn(dev->udev->dev.parent,
+			 "Unhandled message (%d)\n", msg->id);
+		break;
+	}
+}
+
+static void kvaser_usb_read_bulk_callback(struct urb *urb)
+{
+	struct kvaser_usb *dev = urb->context;
+	struct kvaser_msg *msg;
+	int pos = 0;
+	int err, i;
+
+	switch (urb->status) {
+	case 0:
+		break;
+	case -ENOENT:
+	case -ESHUTDOWN:
+		return;
+	default:
+		dev_info(dev->udev->dev.parent, "Rx URB aborted (%d)\n",
+			 urb->status);
+		goto resubmit_urb;
+	}
+
+	while (pos <= urb->actual_length - MSG_HEADER_LEN) {
+		msg = urb->transfer_buffer + pos;
+
+		if (!msg->len)
+			break;
+
+		if (pos + msg->len > urb->actual_length) {
+			dev_err(dev->udev->dev.parent, "Format error\n");
+			break;
+		}
+
+		kvaser_usb_handle_message(dev, msg);
+
+		pos += msg->len;
+	}
+
+resubmit_urb:
+	usb_fill_bulk_urb(urb, dev->udev,
+			  usb_rcvbulkpipe(dev->udev,
+					  dev->bulk_in->bEndpointAddress),
+			  urb->transfer_buffer, RX_BUFFER_SIZE,
+			  kvaser_usb_read_bulk_callback, dev);
+
+	err = usb_submit_urb(urb, GFP_ATOMIC);
+	if (err == -ENODEV) {
+		for (i = 0; i < dev->nchannels; i++) {
+			if (!dev->nets[i])
+				continue;
+
+			netif_device_detach(dev->nets[i]->netdev);
+		}
+	} else if (err) {
+		dev_err(dev->udev->dev.parent,
+			"Failed resubmitting read bulk urb: %d\n", err);
+	}
+
+	return;
+}
+
+static int kvaser_usb_setup_rx_urbs(struct kvaser_usb *dev)
+{
+	int i, err = 0;
+
+	if (dev->rxinitdone)
+		return 0;
+
+	for (i = 0; i < MAX_RX_URBS; i++) {
+		struct urb *urb = NULL;
+		u8 *buf = NULL;
+		dma_addr_t buf_dma;
+
+		urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!urb) {
+			dev_warn(dev->udev->dev.parent,
+				 "No memory left for URBs\n");
+			err = -ENOMEM;
+			break;
+		}
+
+		buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE,
+					 GFP_KERNEL, &buf_dma);
+		if (!buf) {
+			dev_warn(dev->udev->dev.parent,
+				 "No memory left for USB buffer\n");
+			usb_free_urb(urb);
+			err = -ENOMEM;
+			break;
+		}
+
+		usb_fill_bulk_urb(urb, dev->udev,
+				  usb_rcvbulkpipe(dev->udev,
+					  dev->bulk_in->bEndpointAddress),
+				  buf, RX_BUFFER_SIZE,
+				  kvaser_usb_read_bulk_callback,
+				  dev);
+		urb->transfer_dma = buf_dma;
+		urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+		usb_anchor_urb(urb, &dev->rx_submitted);
+
+		err = usb_submit_urb(urb, GFP_KERNEL);
+		if (err) {
+			usb_unanchor_urb(urb);
+			usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
+					  buf_dma);
+			usb_free_urb(urb);
+			break;
+		}
+
+		dev->rxbuf[i] = buf;
+		dev->rxbuf_dma[i] = buf_dma;
+
+		usb_free_urb(urb);
+	}
+
+	if (i == 0) {
+		dev_warn(dev->udev->dev.parent,
+			 "Cannot setup read URBs, error %d\n", err);
+		return err;
+	} else if (i < MAX_RX_URBS) {
+		dev_warn(dev->udev->dev.parent,
+			 "RX performances may be slow\n");
+	}
+
+	dev->rxinitdone = true;
+
+	return 0;
+}
+
+static int kvaser_usb_set_opt_mode(const struct kvaser_usb_net_priv *priv)
+{
+	struct kvaser_msg *msg;
+	int rc;
+
+	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	msg->id = CMD_SET_CTRL_MODE;
+	msg->len = MSG_HEADER_LEN + sizeof(struct kvaser_msg_ctrl_mode);
+	msg->u.ctrl_mode.tid = 0xff;
+	msg->u.ctrl_mode.channel = priv->channel;
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+		msg->u.ctrl_mode.ctrl_mode = KVASER_CTRL_MODE_SILENT;
+	else
+		msg->u.ctrl_mode.ctrl_mode = KVASER_CTRL_MODE_NORMAL;
+
+	rc = kvaser_usb_send_msg(priv->dev, msg);
+
+	kfree(msg);
+	return rc;
+}
+
+static int kvaser_usb_start_chip(struct kvaser_usb_net_priv *priv)
+{
+	int err;
+
+	init_completion(&priv->start_comp);
+
+	err = kvaser_usb_send_simple_msg(priv->dev, CMD_START_CHIP,
+					 priv->channel);
+	if (err)
+		return err;
+
+	if (!wait_for_completion_timeout(&priv->start_comp,
+					 msecs_to_jiffies(START_TIMEOUT)))
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int kvaser_usb_open(struct net_device *netdev)
+{
+	struct kvaser_usb_net_priv *priv = netdev_priv(netdev);
+	struct kvaser_usb *dev = priv->dev;
+	int err;
+
+	err = open_candev(netdev);
+	if (err)
+		return err;
+
+	err = kvaser_usb_setup_rx_urbs(dev);
+	if (err)
+		goto error;
+
+	err = kvaser_usb_set_opt_mode(priv);
+	if (err)
+		goto error;
+
+	err = kvaser_usb_start_chip(priv);
+	if (err) {
+		netdev_warn(netdev, "Cannot start device, error %d\n", err);
+		goto error;
+	}
+
+	priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	return 0;
+
+error:
+	close_candev(netdev);
+	return err;
+}
+
+static void kvaser_usb_unlink_all_urbs(struct kvaser_usb *dev)
+{
+	int i;
+
+	usb_kill_anchored_urbs(&dev->rx_submitted);
+
+	for (i = 0; i < MAX_RX_URBS; i++)
+		usb_free_coherent(dev->udev, RX_BUFFER_SIZE,
+				  dev->rxbuf[i],
+				  dev->rxbuf_dma[i]);
+
+	for (i = 0; i < MAX_NET_DEVICES; i++) {
+		struct kvaser_usb_net_priv *priv = dev->nets[i];
+
+		if (priv)
+			kvaser_usb_unlink_tx_urbs(priv);
+	}
+}
+
+static int kvaser_usb_stop_chip(struct kvaser_usb_net_priv *priv)
+{
+	int err;
+
+	init_completion(&priv->stop_comp);
+
+	err = kvaser_usb_send_simple_msg(priv->dev, CMD_STOP_CHIP,
+					 priv->channel);
+	if (err)
+		return err;
+
+	if (!wait_for_completion_timeout(&priv->stop_comp,
+					 msecs_to_jiffies(STOP_TIMEOUT)))
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int kvaser_usb_flush_queue(struct kvaser_usb_net_priv *priv)
+{
+	struct kvaser_msg *msg;
+	int rc;
+
+	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	msg->id = CMD_FLUSH_QUEUE;
+	msg->len = MSG_HEADER_LEN + sizeof(struct kvaser_msg_flush_queue);
+	msg->u.flush_queue.channel = priv->channel;
+	msg->u.flush_queue.flags = 0x00;
+
+	rc = kvaser_usb_send_msg(priv->dev, msg);
+
+	kfree(msg);
+	return rc;
+}
+
+static int kvaser_usb_close(struct net_device *netdev)
+{
+	struct kvaser_usb_net_priv *priv = netdev_priv(netdev);
+	struct kvaser_usb *dev = priv->dev;
+	int err;
+
+	netif_stop_queue(netdev);
+
+	err = kvaser_usb_flush_queue(priv);
+	if (err)
+		netdev_warn(netdev, "Cannot flush queue, error %d\n", err);
+
+	if (kvaser_usb_send_simple_msg(dev, CMD_RESET_CHIP, priv->channel))
+		netdev_warn(netdev, "Cannot reset card, error %d\n", err);
+
+	err = kvaser_usb_stop_chip(priv);
+	if (err)
+		netdev_warn(netdev, "Cannot stop device, error %d\n", err);
+
+	priv->can.state = CAN_STATE_STOPPED;
+	close_candev(priv->netdev);
+
+	return 0;
+}
+
+static void kvaser_usb_write_bulk_callback(struct urb *urb)
+{
+	struct kvaser_usb_tx_urb_context *context = urb->context;
+	struct kvaser_usb_net_priv *priv;
+	struct net_device *netdev;
+
+	if (WARN_ON(!context))
+		return;
+
+	priv = context->priv;
+	netdev = priv->netdev;
+
+	kfree(urb->transfer_buffer);
+
+	if (!netif_device_present(netdev))
+		return;
+
+	if (urb->status)
+		netdev_info(netdev, "Tx URB aborted (%d)\n", urb->status);
+}
+
+static netdev_tx_t kvaser_usb_start_xmit(struct sk_buff *skb,
+					 struct net_device *netdev)
+{
+	struct kvaser_usb_net_priv *priv = netdev_priv(netdev);
+	struct kvaser_usb *dev = priv->dev;
+	struct net_device_stats *stats = &netdev->stats;
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	struct kvaser_usb_tx_urb_context *context = NULL;
+	struct urb *urb;
+	void *buf;
+	struct kvaser_msg *msg;
+	int i, err;
+	int ret = NETDEV_TX_OK;
+
+	if (can_dropped_invalid_skb(netdev, skb))
+		return NETDEV_TX_OK;
+
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if (!urb) {
+		netdev_err(netdev, "No memory left for URBs\n");
+		stats->tx_dropped++;
+		goto nourbmem;
+	}
+
+	buf = kmalloc(sizeof(struct kvaser_msg), GFP_ATOMIC);
+	if (!buf) {
+		netdev_err(netdev, "No memory left for USB buffer\n");
+		stats->tx_dropped++;
+		goto nobufmem;
+	}
+
+	msg = buf;
+	msg->len = MSG_HEADER_LEN + sizeof(struct kvaser_msg_tx_can);
+	msg->u.tx_can.flags = 0;
+	msg->u.tx_can.channel = priv->channel;
+
+	if (cf->can_id & CAN_EFF_FLAG) {
+		msg->id = CMD_TX_EXT_MESSAGE;
+		msg->u.tx_can.msg[0] = (cf->can_id >> 24) & 0x1f;
+		msg->u.tx_can.msg[1] = (cf->can_id >> 18) & 0x3f;
+		msg->u.tx_can.msg[2] = (cf->can_id >> 14) & 0x0f;
+		msg->u.tx_can.msg[3] = (cf->can_id >> 6) & 0xff;
+		msg->u.tx_can.msg[4] = cf->can_id & 0x3f;
+	} else {
+		msg->id = CMD_TX_STD_MESSAGE;
+		msg->u.tx_can.msg[0] = (cf->can_id >> 6) & 0x1f;
+		msg->u.tx_can.msg[1] = cf->can_id & 0x3f;
+	}
+
+	msg->u.tx_can.msg[5] = cf->can_dlc;
+	memcpy(&msg->u.tx_can.msg[6], cf->data, cf->can_dlc);
+
+	if (cf->can_id & CAN_RTR_FLAG)
+		msg->u.tx_can.flags |= MSG_FLAG_REMOTE_FRAME;
+
+	for (i = 0; i < ARRAY_SIZE(priv->tx_contexts); i++) {
+		if (priv->tx_contexts[i].echo_index == MAX_TX_URBS) {
+			context = &priv->tx_contexts[i];
+			break;
+		}
+	}
+
+	if (!context) {
+		netdev_warn(netdev, "cannot find free context\n");
+		ret =  NETDEV_TX_BUSY;
+		goto releasebuf;
+	}
+
+	context->priv = priv;
+	context->echo_index = i;
+	context->dlc = cf->can_dlc;
+
+	msg->u.tx_can.tid = context->echo_index;
+
+	usb_fill_bulk_urb(urb, dev->udev,
+			  usb_sndbulkpipe(dev->udev,
+					  dev->bulk_out->bEndpointAddress),
+			  buf, msg->len,
+			  kvaser_usb_write_bulk_callback, context);
+	usb_anchor_urb(urb, &priv->tx_submitted);
+
+	can_put_echo_skb(skb, netdev, context->echo_index);
+
+	atomic_inc(&priv->active_tx_urbs);
+
+	if (atomic_read(&priv->active_tx_urbs) >= MAX_TX_URBS)
+		netif_stop_queue(netdev);
+
+	err = usb_submit_urb(urb, GFP_ATOMIC);
+	if (unlikely(err)) {
+		can_free_echo_skb(netdev, context->echo_index);
+
+		skb = NULL; /* set to NULL to avoid double free in
+			     * dev_kfree_skb(skb) */
+
+		atomic_dec(&priv->active_tx_urbs);
+		usb_unanchor_urb(urb);
+
+		stats->tx_dropped++;
+
+		if (err == -ENODEV)
+			netif_device_detach(netdev);
+		else
+			netdev_warn(netdev, "Failed tx_urb %d\n", err);
+
+		goto releasebuf;
+	}
+
+	usb_free_urb(urb);
+
+	return NETDEV_TX_OK;
+
+releasebuf:
+	kfree(buf);
+nobufmem:
+	usb_free_urb(urb);
+nourbmem:
+	dev_kfree_skb(skb);
+	return ret;
+}
+
+static const struct net_device_ops kvaser_usb_netdev_ops = {
+	.ndo_open = kvaser_usb_open,
+	.ndo_stop = kvaser_usb_close,
+	.ndo_start_xmit = kvaser_usb_start_xmit,
+};
+
+static const struct can_bittiming_const kvaser_usb_bittiming_const = {
+	.name = "kvaser_usb",
+	.tseg1_min = KVASER_USB_TSEG1_MIN,
+	.tseg1_max = KVASER_USB_TSEG1_MAX,
+	.tseg2_min = KVASER_USB_TSEG2_MIN,
+	.tseg2_max = KVASER_USB_TSEG2_MAX,
+	.sjw_max = KVASER_USB_SJW_MAX,
+	.brp_min = KVASER_USB_BRP_MIN,
+	.brp_max = KVASER_USB_BRP_MAX,
+	.brp_inc = KVASER_USB_BRP_INC,
+};
+
+static int kvaser_usb_set_bittiming(struct net_device *netdev)
+{
+	struct kvaser_usb_net_priv *priv = netdev_priv(netdev);
+	struct can_bittiming *bt = &priv->can.bittiming;
+	struct kvaser_usb *dev = priv->dev;
+	struct kvaser_msg *msg;
+	int rc;
+
+	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	msg->id = CMD_SET_BUS_PARAMS;
+	msg->len = MSG_HEADER_LEN + sizeof(struct kvaser_msg_busparams);
+	msg->u.busparams.channel = priv->channel;
+	msg->u.busparams.tid = 0xff;
+	msg->u.busparams.bitrate = cpu_to_le32(bt->bitrate);
+	msg->u.busparams.sjw = bt->sjw;
+	msg->u.busparams.tseg1 = bt->prop_seg + bt->phase_seg1;
+	msg->u.busparams.tseg2 = bt->phase_seg2;
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
+		msg->u.busparams.no_samp = 3;
+	else
+		msg->u.busparams.no_samp = 1;
+
+	rc = kvaser_usb_send_msg(dev, msg);
+
+	kfree(msg);
+	return rc;
+}
+
+static int kvaser_usb_set_mode(struct net_device *netdev,
+			       enum can_mode mode)
+{
+	struct kvaser_usb_net_priv *priv = netdev_priv(netdev);
+	int err;
+
+	switch (mode) {
+	case CAN_MODE_START:
+		err = kvaser_usb_simple_msg_async(priv, CMD_START_CHIP);
+		if (err)
+			return err;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int kvaser_usb_get_berr_counter(const struct net_device *netdev,
+				       struct can_berr_counter *bec)
+{
+	struct kvaser_usb_net_priv *priv = netdev_priv(netdev);
+
+	*bec = priv->bec;
+
+	return 0;
+}
+
+static void kvaser_usb_remove_interfaces(struct kvaser_usb *dev)
+{
+	int i;
+
+	for (i = 0; i < dev->nchannels; i++) {
+		if (!dev->nets[i])
+			continue;
+
+		unregister_netdev(dev->nets[i]->netdev);
+	}
+
+	kvaser_usb_unlink_all_urbs(dev);
+
+	for (i = 0; i < dev->nchannels; i++) {
+		if (!dev->nets[i])
+			continue;
+
+		free_candev(dev->nets[i]->netdev);
+	}
+}
+
+static int kvaser_usb_init_one(struct usb_interface *intf,
+			       const struct usb_device_id *id, int channel)
+{
+	struct kvaser_usb *dev = usb_get_intfdata(intf);
+	struct net_device *netdev;
+	struct kvaser_usb_net_priv *priv;
+	int i, err;
+
+	netdev = alloc_candev(sizeof(*priv), MAX_TX_URBS);
+	if (!netdev) {
+		dev_err(&intf->dev, "Cannot alloc candev\n");
+		return -ENOMEM;
+	}
+
+	priv = netdev_priv(netdev);
+
+	init_completion(&priv->start_comp);
+	init_completion(&priv->stop_comp);
+
+	init_usb_anchor(&priv->tx_submitted);
+	atomic_set(&priv->active_tx_urbs, 0);
+
+	for (i = 0; i < ARRAY_SIZE(priv->tx_contexts); i++)
+		priv->tx_contexts[i].echo_index = MAX_TX_URBS;
+
+	priv->dev = dev;
+	priv->netdev = netdev;
+	priv->channel = channel;
+
+	priv->can.state = CAN_STATE_STOPPED;
+	priv->can.clock.freq = CAN_USB_CLOCK;
+	priv->can.bittiming_const = &kvaser_usb_bittiming_const;
+	priv->can.do_set_bittiming = kvaser_usb_set_bittiming;
+	priv->can.do_set_mode = kvaser_usb_set_mode;
+	if (id->driver_info & KVASER_HAS_TXRX_ERRORS)
+		priv->can.do_get_berr_counter = kvaser_usb_get_berr_counter;
+	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
+	if (id->driver_info & KVASER_HAS_SILENT_MODE)
+		priv->can.ctrlmode_supported |= CAN_CTRLMODE_LISTENONLY;
+
+	netdev->flags |= IFF_ECHO;
+
+	netdev->netdev_ops = &kvaser_usb_netdev_ops;
+
+	SET_NETDEV_DEV(netdev, &intf->dev);
+
+	dev->nets[channel] = priv;
+
+	err = register_candev(netdev);
+	if (err) {
+		dev_err(&intf->dev, "Failed to register can device\n");
+		free_candev(netdev);
+		dev->nets[channel] = NULL;
+		return err;
+	}
+
+	netdev_dbg(netdev, "device registered\n");
+
+	return 0;
+}
+
+static void kvaser_usb_get_endpoints(const struct usb_interface *intf,
+				     struct usb_endpoint_descriptor **in,
+				     struct usb_endpoint_descriptor **out)
+{
+	const struct usb_host_interface *iface_desc;
+	struct usb_endpoint_descriptor *endpoint;
+	int i;
+
+	iface_desc = &intf->altsetting[0];
+
+	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
+		endpoint = &iface_desc->endpoint[i].desc;
+
+		if (usb_endpoint_is_bulk_in(endpoint))
+			*in = endpoint;
+
+		if (usb_endpoint_is_bulk_out(endpoint))
+			*out = endpoint;
+	}
+}
+
+static int kvaser_usb_probe(struct usb_interface *intf,
+			    const struct usb_device_id *id)
+{
+	struct kvaser_usb *dev;
+	int err = -ENOMEM;
+	int i;
+
+	dev = devm_kzalloc(&intf->dev, sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	kvaser_usb_get_endpoints(intf, &dev->bulk_in, &dev->bulk_out);
+	if (!dev->bulk_in || !dev->bulk_out) {
+		dev_err(&intf->dev, "Cannot get usb endpoint(s)");
+		return err;
+	}
+
+	dev->udev = interface_to_usbdev(intf);
+
+	init_usb_anchor(&dev->rx_submitted);
+
+	usb_set_intfdata(intf, dev);
+
+	for (i = 0; i < MAX_NET_DEVICES; i++)
+		kvaser_usb_send_simple_msg(dev, CMD_RESET_CHIP, i);
+
+	err = kvaser_usb_get_software_info(dev);
+	if (err) {
+		dev_err(&intf->dev,
+			"Cannot get software infos, error %d\n", err);
+		return err;
+	}
+
+	err = kvaser_usb_get_card_info(dev);
+	if (err) {
+		dev_err(&intf->dev,
+			"Cannot get card infos, error %d\n", err);
+		return err;
+	}
+
+	dev_dbg(&intf->dev, "Firmware version: %d.%d.%d\n",
+		((dev->fw_version >> 24) & 0xff),
+		((dev->fw_version >> 16) & 0xff),
+		(dev->fw_version & 0xffff));
+
+	for (i = 0; i < dev->nchannels; i++) {
+		err = kvaser_usb_init_one(intf, id, i);
+		if (err) {
+			kvaser_usb_remove_interfaces(dev);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static void kvaser_usb_disconnect(struct usb_interface *intf)
+{
+	struct kvaser_usb *dev = usb_get_intfdata(intf);
+
+	usb_set_intfdata(intf, NULL);
+
+	if (!dev)
+		return;
+
+	kvaser_usb_remove_interfaces(dev);
+}
+
+static struct usb_driver kvaser_usb_driver = {
+	.name = "kvaser_usb",
+	.probe = kvaser_usb_probe,
+	.disconnect = kvaser_usb_disconnect,
+	.id_table = kvaser_usb_table,
+};
+
+module_usb_driver(kvaser_usb_driver);
+
+MODULE_AUTHOR("Olivier Sobrie <olivier@sobrie.be>");
+MODULE_DESCRIPTION("CAN driver for Kvaser CAN/USB devices");
+MODULE_LICENSE("GPL v2");