can: usb: PEAK-System Technik PCAN-USB specific part

This patch adds the specific part which handles the PCAN-USB adapter from
PEAK-System Technik (http://www.peak-system.com). The PCAN-USB adapter is
a sja1000 based, mono-channel USB 1.1 adapter compliant with CAN
specifications 2.0A (11-bit ID) and 2.0B (29-bit ID).

Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

2 files changed, 902 insertions, 1 deletions

diff --git a/drivers/net/can/usb/peak_usb/Makefile b/drivers/net/can/usb/peak_usb/Makefile
index bbb23ceb65f..4450466fa57 100644
--- a/drivers/net/can/usb/peak_usb/Makefile
+++ b/drivers/net/can/usb/peak_usb/Makefile
@@ -1,2 +1,2 @@
 obj-$(CONFIG_CAN_PEAK_USB) += peak_usb.o
-peak_usb-y = pcan_usb_core.o
+peak_usb-y = pcan_usb_core.o pcan_usb.o
diff --git a/drivers/net/can/usb/peak_usb/pcan_usb.c b/drivers/net/can/usb/peak_usb/pcan_usb.c
new file mode 100644
index 00000000000..8a7982e18e4
--- /dev/null
+++ b/drivers/net/can/usb/peak_usb/pcan_usb.c
@@ -0,0 +1,901 @@
+/*
+ * CAN driver for PEAK System PCAN-USB adapter
+ * Derived from the PCAN project file driver/src/pcan_usb.c
+ *
+ * Copyright (C) 2003-2010 PEAK System-Technik GmbH
+ * Copyright (C) 2011-2012 Stephane Grosjean <s.grosjean@peak-system.com>
+ *
+ * Many thanks to Klaus Hitschler <klaus.hitschler@gmx.de>
+ *
+ * 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 of the License.
+ *
+ * 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.
+ */
+#include <linux/netdevice.h>
+#include <linux/usb.h>
+#include <linux/module.h>
+
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+
+#include "pcan_usb_core.h"
+
+MODULE_SUPPORTED_DEVICE("PEAK-System PCAN-USB adapter");
+
+/* PCAN-USB Endpoints */
+#define PCAN_USB_EP_CMDOUT		1
+#define PCAN_USB_EP_CMDIN		(PCAN_USB_EP_CMDOUT | USB_DIR_IN)
+#define PCAN_USB_EP_MSGOUT		2
+#define PCAN_USB_EP_MSGIN		(PCAN_USB_EP_MSGOUT | USB_DIR_IN)
+
+/* PCAN-USB command struct */
+#define PCAN_USB_CMD_FUNC		0
+#define PCAN_USB_CMD_NUM		1
+#define PCAN_USB_CMD_ARGS		2
+#define PCAN_USB_CMD_ARGS_LEN		14
+#define PCAN_USB_CMD_LEN		(PCAN_USB_CMD_ARGS + \
+					 PCAN_USB_CMD_ARGS_LEN)
+
+/* PCAN-USB command timeout (ms.) */
+#define PCAN_USB_COMMAND_TIMEOUT	1000
+
+/* PCAN-USB startup timeout (ms.) */
+#define PCAN_USB_STARTUP_TIMEOUT	10
+
+/* PCAN-USB rx/tx buffers size */
+#define PCAN_USB_RX_BUFFER_SIZE		64
+#define PCAN_USB_TX_BUFFER_SIZE		64
+
+#define PCAN_USB_MSG_HEADER_LEN		2
+
+/* PCAN-USB adapter internal clock (MHz) */
+#define PCAN_USB_CRYSTAL_HZ		16000000
+
+/* PCAN-USB USB message record status/len field */
+#define PCAN_USB_STATUSLEN_TIMESTAMP	(1 << 7)
+#define PCAN_USB_STATUSLEN_INTERNAL	(1 << 6)
+#define PCAN_USB_STATUSLEN_EXT_ID	(1 << 5)
+#define PCAN_USB_STATUSLEN_RTR		(1 << 4)
+#define PCAN_USB_STATUSLEN_DLC		(0xf)
+
+/* PCAN-USB error flags */
+#define PCAN_USB_ERROR_TXFULL		0x01
+#define PCAN_USB_ERROR_RXQOVR		0x02
+#define PCAN_USB_ERROR_BUS_LIGHT	0x04
+#define PCAN_USB_ERROR_BUS_HEAVY	0x08
+#define PCAN_USB_ERROR_BUS_OFF		0x10
+#define PCAN_USB_ERROR_RXQEMPTY		0x20
+#define PCAN_USB_ERROR_QOVR		0x40
+#define PCAN_USB_ERROR_TXQFULL		0x80
+
+/* SJA1000 modes */
+#define SJA1000_MODE_NORMAL		0x00
+#define SJA1000_MODE_INIT		0x01
+
+/*
+ * tick duration = 42.666 us =>
+ * (tick_number * 44739243) >> 20 ~ (tick_number * 42666) / 1000
+ * accuracy = 10^-7
+ */
+#define PCAN_USB_TS_DIV_SHIFTER		20
+#define PCAN_USB_TS_US_PER_TICK		44739243
+
+/* PCAN-USB messages record types */
+#define PCAN_USB_REC_ERROR		1
+#define PCAN_USB_REC_ANALOG		2
+#define PCAN_USB_REC_BUSLOAD		3
+#define PCAN_USB_REC_TS			4
+#define PCAN_USB_REC_BUSEVT		5
+
+/* private to PCAN-USB adapter */
+struct pcan_usb {
+	struct peak_usb_device dev;
+	struct peak_time_ref time_ref;
+	struct timer_list restart_timer;
+};
+
+/* incoming message context for decoding */
+struct pcan_usb_msg_context {
+	u16 ts16;
+	u8 prev_ts8;
+	u8 *ptr;
+	u8 *end;
+	u8 rec_cnt;
+	u8 rec_idx;
+	u8 rec_data_idx;
+	struct net_device *netdev;
+	struct pcan_usb *pdev;
+};
+
+/*
+ * send a command
+ */
+static int pcan_usb_send_cmd(struct peak_usb_device *dev, u8 f, u8 n, u8 *p)
+{
+	int err;
+	int actual_length;
+
+	/* usb device unregistered? */
+	if (!(dev->state & PCAN_USB_STATE_CONNECTED))
+		return 0;
+
+	dev->cmd_buf[PCAN_USB_CMD_FUNC] = f;
+	dev->cmd_buf[PCAN_USB_CMD_NUM] = n;
+
+	if (p)
+		memcpy(dev->cmd_buf + PCAN_USB_CMD_ARGS,
+			p, PCAN_USB_CMD_ARGS_LEN);
+
+	err = usb_bulk_msg(dev->udev,
+			usb_sndbulkpipe(dev->udev, PCAN_USB_EP_CMDOUT),
+			dev->cmd_buf, PCAN_USB_CMD_LEN, &actual_length,
+			PCAN_USB_COMMAND_TIMEOUT);
+	if (err)
+		netdev_err(dev->netdev,
+			"sending cmd f=0x%x n=0x%x failure: %d\n",
+			f, n, err);
+	return err;
+}
+
+/*
+ * send a command then wait for its response
+ */
+static int pcan_usb_wait_rsp(struct peak_usb_device *dev, u8 f, u8 n, u8 *p)
+{
+	int err;
+	int actual_length;
+
+	/* usb device unregistered? */
+	if (!(dev->state & PCAN_USB_STATE_CONNECTED))
+		return 0;
+
+	/* first, send command */
+	err = pcan_usb_send_cmd(dev, f, n, NULL);
+	if (err)
+		return err;
+
+	err = usb_bulk_msg(dev->udev,
+		usb_rcvbulkpipe(dev->udev, PCAN_USB_EP_CMDIN),
+		dev->cmd_buf, PCAN_USB_CMD_LEN, &actual_length,
+		PCAN_USB_COMMAND_TIMEOUT);
+	if (err)
+		netdev_err(dev->netdev,
+			"waiting rsp f=0x%x n=0x%x failure: %d\n", f, n, err);
+	else if (p)
+		memcpy(p, dev->cmd_buf + PCAN_USB_CMD_ARGS,
+			PCAN_USB_CMD_ARGS_LEN);
+
+	return err;
+}
+
+static int pcan_usb_set_sja1000(struct peak_usb_device *dev, u8 mode)
+{
+	u8 args[PCAN_USB_CMD_ARGS_LEN] = {
+		[1] = mode,
+	};
+
+	return pcan_usb_send_cmd(dev, 9, 2, args);
+}
+
+static int pcan_usb_set_bus(struct peak_usb_device *dev, u8 onoff)
+{
+	u8 args[PCAN_USB_CMD_ARGS_LEN] = {
+		[0] = !!onoff,
+	};
+
+	return pcan_usb_send_cmd(dev, 3, 2, args);
+}
+
+static int pcan_usb_set_silent(struct peak_usb_device *dev, u8 onoff)
+{
+	u8 args[PCAN_USB_CMD_ARGS_LEN] = {
+		[0] = !!onoff,
+	};
+
+	return pcan_usb_send_cmd(dev, 3, 3, args);
+}
+
+static int pcan_usb_set_ext_vcc(struct peak_usb_device *dev, u8 onoff)
+{
+	u8 args[PCAN_USB_CMD_ARGS_LEN] = {
+		[0] = !!onoff,
+	};
+
+	return pcan_usb_send_cmd(dev, 10, 2, args);
+}
+
+/*
+ * set bittiming value to can
+ */
+static int pcan_usb_set_bittiming(struct peak_usb_device *dev,
+				  struct can_bittiming *bt)
+{
+	u8 args[PCAN_USB_CMD_ARGS_LEN];
+	u8 btr0, btr1;
+
+	btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
+	btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
+		(((bt->phase_seg2 - 1) & 0x7) << 4);
+	if (dev->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
+		btr1 |= 0x80;
+
+	netdev_info(dev->netdev, "setting BTR0=0x%02x BTR1=0x%02x\n",
+		btr0, btr1);
+
+	args[0] = btr1;
+	args[1] = btr0;
+
+	return pcan_usb_send_cmd(dev, 1, 2, args);
+}
+
+/*
+ * init/reset can
+ */
+static int pcan_usb_write_mode(struct peak_usb_device *dev, u8 onoff)
+{
+	int err;
+
+	err = pcan_usb_set_bus(dev, onoff);
+	if (err)
+		return err;
+
+	if (!onoff) {
+		err = pcan_usb_set_sja1000(dev, SJA1000_MODE_INIT);
+	} else {
+		/* the PCAN-USB needs time to init */
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(msecs_to_jiffies(PCAN_USB_STARTUP_TIMEOUT));
+	}
+
+	return err;
+}
+
+/*
+ * handle end of waiting for the device to reset
+ */
+static void pcan_usb_restart(unsigned long arg)
+{
+	/* notify candev and netdev */
+	peak_usb_restart_complete((struct peak_usb_device *)arg);
+}
+
+/*
+ * handle the submission of the restart urb
+ */
+static void pcan_usb_restart_pending(struct urb *urb)
+{
+	struct pcan_usb *pdev = urb->context;
+
+	/* the PCAN-USB needs time to restart */
+	mod_timer(&pdev->restart_timer,
+			jiffies + msecs_to_jiffies(PCAN_USB_STARTUP_TIMEOUT));
+
+	/* can delete usb resources */
+	peak_usb_async_complete(urb);
+}
+
+/*
+ * handle asynchronous restart
+ */
+static int pcan_usb_restart_async(struct peak_usb_device *dev, struct urb *urb,
+				  u8 *buf)
+{
+	struct pcan_usb *pdev = container_of(dev, struct pcan_usb, dev);
+
+	if (timer_pending(&pdev->restart_timer))
+		return -EBUSY;
+
+	/* set bus on */
+	buf[PCAN_USB_CMD_FUNC] = 3;
+	buf[PCAN_USB_CMD_NUM] = 2;
+	buf[PCAN_USB_CMD_ARGS] = 1;
+
+	usb_fill_bulk_urb(urb, dev->udev,
+			usb_sndbulkpipe(dev->udev, PCAN_USB_EP_CMDOUT),
+			buf, PCAN_USB_CMD_LEN,
+			pcan_usb_restart_pending, pdev);
+
+	return usb_submit_urb(urb, GFP_ATOMIC);
+}
+
+/*
+ * read serial number from device
+ */
+static int pcan_usb_get_serial(struct peak_usb_device *dev, u32 *serial_number)
+{
+	u8 args[PCAN_USB_CMD_ARGS_LEN];
+	int err;
+
+	err = pcan_usb_wait_rsp(dev, 6, 1, args);
+	if (err) {
+		netdev_err(dev->netdev, "getting serial failure: %d\n", err);
+	} else if (serial_number) {
+		u32 tmp32;
+
+		memcpy(&tmp32, args, 4);
+		*serial_number = le32_to_cpu(tmp32);
+	}
+
+	return err;
+}
+
+/*
+ * read device id from device
+ */
+static int pcan_usb_get_device_id(struct peak_usb_device *dev, u32 *device_id)
+{
+	u8 args[PCAN_USB_CMD_ARGS_LEN];
+	int err;
+
+	err = pcan_usb_wait_rsp(dev, 4, 1, args);
+	if (err)
+		netdev_err(dev->netdev, "getting device id failure: %d\n", err);
+	else if (device_id)
+		*device_id = args[0];
+
+	return err;
+}
+
+/*
+ * update current time ref with received timestamp
+ */
+static int pcan_usb_update_ts(struct pcan_usb_msg_context *mc)
+{
+	u16 tmp16;
+
+	if ((mc->ptr+2) > mc->end)
+		return -EINVAL;
+
+	memcpy(&tmp16, mc->ptr, 2);
+
+	mc->ts16 = le16_to_cpu(tmp16);
+
+	if (mc->rec_idx > 0)
+		peak_usb_update_ts_now(&mc->pdev->time_ref, mc->ts16);
+	else
+		peak_usb_set_ts_now(&mc->pdev->time_ref, mc->ts16);
+
+	return 0;
+}
+
+/*
+ * decode received timestamp
+ */
+static int pcan_usb_decode_ts(struct pcan_usb_msg_context *mc, u8 first_packet)
+{
+	/* only 1st packet supplies a word timestamp */
+	if (first_packet) {
+		u16 tmp16;
+
+		if ((mc->ptr + 2) > mc->end)
+			return -EINVAL;
+
+		memcpy(&tmp16, mc->ptr, 2);
+		mc->ptr += 2;
+
+		mc->ts16 = le16_to_cpu(tmp16);
+		mc->prev_ts8 = mc->ts16 & 0x00ff;
+	} else {
+		u8 ts8;
+
+		if ((mc->ptr + 1) > mc->end)
+			return -EINVAL;
+
+		ts8 = *mc->ptr++;
+
+		if (ts8 < mc->prev_ts8)
+			mc->ts16 += 0x100;
+
+		mc->ts16 &= 0xff00;
+		mc->ts16 |= ts8;
+		mc->prev_ts8 = ts8;
+	}
+
+	return 0;
+}
+
+static int pcan_usb_decode_error(struct pcan_usb_msg_context *mc, u8 n,
+				 u8 status_len)
+{
+	struct sk_buff *skb;
+	struct can_frame *cf;
+	struct timeval tv;
+	enum can_state new_state;
+
+	/* ignore this error until 1st ts received */
+	if (n == PCAN_USB_ERROR_QOVR)
+		if (!mc->pdev->time_ref.tick_count)
+			return 0;
+
+	new_state = mc->pdev->dev.can.state;
+
+	switch (mc->pdev->dev.can.state) {
+	case CAN_STATE_ERROR_ACTIVE:
+		if (n & PCAN_USB_ERROR_BUS_LIGHT) {
+			new_state = CAN_STATE_ERROR_WARNING;
+			break;
+		}
+
+	case CAN_STATE_ERROR_WARNING:
+		if (n & PCAN_USB_ERROR_BUS_HEAVY) {
+			new_state = CAN_STATE_ERROR_PASSIVE;
+			break;
+		}
+		if (n & PCAN_USB_ERROR_BUS_OFF) {
+			new_state = CAN_STATE_BUS_OFF;
+			break;
+		}
+		if (n & (PCAN_USB_ERROR_RXQOVR | PCAN_USB_ERROR_QOVR)) {
+			/*
+			 * trick to bypass next comparison and process other
+			 * errors
+			 */
+			new_state = CAN_STATE_MAX;
+			break;
+		}
+		if ((n & PCAN_USB_ERROR_BUS_LIGHT) == 0) {
+			/* no error (back to active state) */
+			mc->pdev->dev.can.state = CAN_STATE_ERROR_ACTIVE;
+			return 0;
+		}
+		break;
+
+	case CAN_STATE_ERROR_PASSIVE:
+		if (n & PCAN_USB_ERROR_BUS_OFF) {
+			new_state = CAN_STATE_BUS_OFF;
+			break;
+		}
+		if (n & PCAN_USB_ERROR_BUS_LIGHT) {
+			new_state = CAN_STATE_ERROR_WARNING;
+			break;
+		}
+		if (n & (PCAN_USB_ERROR_RXQOVR | PCAN_USB_ERROR_QOVR)) {
+			/*
+			 * trick to bypass next comparison and process other
+			 * errors
+			 */
+			new_state = CAN_STATE_MAX;
+			break;
+		}
+
+		if ((n & PCAN_USB_ERROR_BUS_HEAVY) == 0) {
+			/* no error (back to active state) */
+			mc->pdev->dev.can.state = CAN_STATE_ERROR_ACTIVE;
+			return 0;
+		}
+		break;
+
+	default:
+		/* do nothing waiting for restart */
+		return 0;
+	}
+
+	/* donot post any error if current state didn't change */
+	if (mc->pdev->dev.can.state == new_state)
+		return 0;
+
+	/* allocate an skb to store the error frame */
+	skb = alloc_can_err_skb(mc->netdev, &cf);
+	if (!skb)
+		return -ENOMEM;
+
+	switch (new_state) {
+	case CAN_STATE_BUS_OFF:
+		cf->can_id |= CAN_ERR_BUSOFF;
+		can_bus_off(mc->netdev);
+		break;
+
+	case CAN_STATE_ERROR_PASSIVE:
+		cf->can_id |= CAN_ERR_CRTL;
+		cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE |
+			       CAN_ERR_CRTL_RX_PASSIVE;
+		mc->pdev->dev.can.can_stats.error_passive++;
+		break;
+
+	case CAN_STATE_ERROR_WARNING:
+		cf->can_id |= CAN_ERR_CRTL;
+		cf->data[1] |= CAN_ERR_CRTL_TX_WARNING |
+			       CAN_ERR_CRTL_RX_WARNING;
+		mc->pdev->dev.can.can_stats.error_warning++;
+		break;
+
+	default:
+		/* CAN_STATE_MAX (trick to handle other errors) */
+		cf->can_id |= CAN_ERR_CRTL;
+		cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW;
+		mc->netdev->stats.rx_over_errors++;
+		mc->netdev->stats.rx_errors++;
+
+		new_state = mc->pdev->dev.can.state;
+		break;
+	}
+
+	mc->pdev->dev.can.state = new_state;
+
+	if (status_len & PCAN_USB_STATUSLEN_TIMESTAMP) {
+		peak_usb_get_ts_tv(&mc->pdev->time_ref, mc->ts16, &tv);
+		skb->tstamp = timeval_to_ktime(tv);
+	}
+
+	netif_rx(skb);
+	mc->netdev->stats.rx_packets++;
+	mc->netdev->stats.rx_bytes += cf->can_dlc;
+
+	return 0;
+}
+
+/*
+ * decode non-data usb message
+ */
+static int pcan_usb_decode_status(struct pcan_usb_msg_context *mc,
+				  u8 status_len)
+{
+	u8 rec_len = status_len & PCAN_USB_STATUSLEN_DLC;
+	u8 f, n;
+	int err;
+
+	/* check whether function and number can be read */
+	if ((mc->ptr + 2) > mc->end)
+		return -EINVAL;
+
+	f = mc->ptr[PCAN_USB_CMD_FUNC];
+	n = mc->ptr[PCAN_USB_CMD_NUM];
+	mc->ptr += PCAN_USB_CMD_ARGS;
+
+	if (status_len & PCAN_USB_STATUSLEN_TIMESTAMP) {
+		int err = pcan_usb_decode_ts(mc, !mc->rec_idx);
+
+		if (err)
+			return err;
+	}
+
+	switch (f) {
+	case PCAN_USB_REC_ERROR:
+		err = pcan_usb_decode_error(mc, n, status_len);
+		if (err)
+			return err;
+		break;
+
+	case PCAN_USB_REC_ANALOG:
+		/* analog values (ignored) */
+		rec_len = 2;
+		break;
+
+	case PCAN_USB_REC_BUSLOAD:
+		/* bus load (ignored) */
+		rec_len = 1;
+		break;
+
+	case PCAN_USB_REC_TS:
+		/* only timestamp */
+		if (pcan_usb_update_ts(mc))
+			return -EINVAL;
+		break;
+
+	case PCAN_USB_REC_BUSEVT:
+		/* error frame/bus event */
+		if (n & PCAN_USB_ERROR_TXQFULL)
+			netdev_dbg(mc->netdev, "device Tx queue full)\n");
+		break;
+	default:
+		netdev_err(mc->netdev, "unexpected function %u\n", f);
+		break;
+	}
+
+	if ((mc->ptr + rec_len) > mc->end)
+		return -EINVAL;
+
+	mc->ptr += rec_len;
+
+	return 0;
+}
+
+/*
+ * decode data usb message
+ */
+static int pcan_usb_decode_data(struct pcan_usb_msg_context *mc, u8 status_len)
+{
+	u8 rec_len = status_len & PCAN_USB_STATUSLEN_DLC;
+	struct sk_buff *skb;
+	struct can_frame *cf;
+	struct timeval tv;
+
+	skb = alloc_can_skb(mc->netdev, &cf);
+	if (!skb)
+		return -ENOMEM;
+
+	if (status_len & PCAN_USB_STATUSLEN_EXT_ID) {
+		u32 tmp32;
+
+		if ((mc->ptr + 4) > mc->end)
+			goto decode_failed;
+
+		memcpy(&tmp32, mc->ptr, 4);
+		mc->ptr += 4;
+
+		cf->can_id = le32_to_cpu(tmp32 >> 3) | CAN_EFF_FLAG;
+	} else {
+		u16 tmp16;
+
+		if ((mc->ptr + 2) > mc->end)
+			goto decode_failed;
+
+		memcpy(&tmp16, mc->ptr, 2);
+		mc->ptr += 2;
+
+		cf->can_id = le16_to_cpu(tmp16 >> 5);
+	}
+
+	cf->can_dlc = get_can_dlc(rec_len);
+
+	/* first data packet timestamp is a word */
+	if (pcan_usb_decode_ts(mc, !mc->rec_data_idx))
+		goto decode_failed;
+
+	/* read data */
+	memset(cf->data, 0x0, sizeof(cf->data));
+	if (status_len & PCAN_USB_STATUSLEN_RTR) {
+		cf->can_id |= CAN_RTR_FLAG;
+	} else {
+		if ((mc->ptr + rec_len) > mc->end)
+			goto decode_failed;
+
+		memcpy(cf->data, mc->ptr, rec_len);
+		mc->ptr += rec_len;
+	}
+
+	/* convert timestamp into kernel time */
+	peak_usb_get_ts_tv(&mc->pdev->time_ref, mc->ts16, &tv);
+	skb->tstamp = timeval_to_ktime(tv);
+
+	/* push the skb */
+	netif_rx(skb);
+
+	/* update statistics */
+	mc->netdev->stats.rx_packets++;
+	mc->netdev->stats.rx_bytes += cf->can_dlc;
+
+	return 0;
+
+decode_failed:
+	dev_kfree_skb(skb);
+	return -EINVAL;
+}
+
+/*
+ * process incoming message
+ */
+static int pcan_usb_decode_msg(struct peak_usb_device *dev, u8 *ibuf, u32 lbuf)
+{
+	struct pcan_usb_msg_context mc = {
+		.rec_cnt = ibuf[1],
+		.ptr = ibuf + PCAN_USB_MSG_HEADER_LEN,
+		.end = ibuf + lbuf,
+		.netdev = dev->netdev,
+		.pdev = container_of(dev, struct pcan_usb, dev),
+	};
+	int err;
+
+	for (err = 0; mc.rec_idx < mc.rec_cnt && !err; mc.rec_idx++) {
+		u8 sl = *mc.ptr++;
+
+		/* handle status and error frames here */
+		if (sl & PCAN_USB_STATUSLEN_INTERNAL) {
+			err = pcan_usb_decode_status(&mc, sl);
+		/* handle normal can frames here */
+		} else {
+			err = pcan_usb_decode_data(&mc, sl);
+			mc.rec_data_idx++;
+		}
+	}
+
+	return err;
+}
+
+/*
+ * process any incoming buffer
+ */
+static int pcan_usb_decode_buf(struct peak_usb_device *dev, struct urb *urb)
+{
+	int err = 0;
+
+	if (urb->actual_length > PCAN_USB_MSG_HEADER_LEN) {
+		err = pcan_usb_decode_msg(dev, urb->transfer_buffer,
+			urb->actual_length);
+
+	} else if (urb->actual_length > 0) {
+		netdev_err(dev->netdev, "usb message length error (%u)\n",
+			urb->actual_length);
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+/*
+ * process outgoing packet
+ */
+static int pcan_usb_encode_msg(struct peak_usb_device *dev, struct sk_buff *skb,
+			       u8 *obuf, size_t *size)
+{
+	struct net_device *netdev = dev->netdev;
+	struct net_device_stats *stats = &netdev->stats;
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	u8 *pc;
+
+	obuf[0] = 2;
+	obuf[1] = 1;
+
+	pc = obuf + PCAN_USB_MSG_HEADER_LEN;
+
+	/* status/len byte */
+	*pc = cf->can_dlc;
+	if (cf->can_id & CAN_RTR_FLAG)
+		*pc |= PCAN_USB_STATUSLEN_RTR;
+
+	/* can id */
+	if (cf->can_id & CAN_EFF_FLAG) {
+		__le32 tmp32 = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
+
+		tmp32 <<= 3;
+		*pc |= PCAN_USB_STATUSLEN_EXT_ID;
+		memcpy(++pc, &tmp32, 4);
+		pc += 4;
+	} else {
+		__le16 tmp16 = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
+
+		tmp16 <<= 5;
+		memcpy(++pc, &tmp16, 2);
+		pc += 2;
+	}
+
+	/* can data */
+	if (!(cf->can_id & CAN_RTR_FLAG)) {
+		memcpy(pc, cf->data, cf->can_dlc);
+		pc += cf->can_dlc;
+	}
+
+	obuf[(*size)-1] = (u8)(stats->tx_packets & 0xff);
+
+	return 0;
+}
+
+/*
+ * start interface
+ */
+static int pcan_usb_start(struct peak_usb_device *dev)
+{
+	struct pcan_usb *pdev = container_of(dev, struct pcan_usb, dev);
+
+	/* number of bits used in timestamps read from adapter struct */
+	peak_usb_init_time_ref(&pdev->time_ref, &pcan_usb);
+
+	/* if revision greater than 3, can put silent mode on/off */
+	if (dev->device_rev > 3) {
+		int err;
+
+		err = pcan_usb_set_silent(dev,
+				dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY);
+		if (err)
+			return err;
+	}
+
+	return pcan_usb_set_ext_vcc(dev, 0);
+}
+
+static int pcan_usb_init(struct peak_usb_device *dev)
+{
+	struct pcan_usb *pdev = container_of(dev, struct pcan_usb, dev);
+	u32 serial_number;
+	int err;
+
+	/* initialize a timer needed to wait for hardware restart */
+	init_timer(&pdev->restart_timer);
+	pdev->restart_timer.function = pcan_usb_restart;
+	pdev->restart_timer.data = (unsigned long)dev;
+
+	/*
+	 * explicit use of dev_xxx() instead of netdev_xxx() here:
+	 * information displayed are related to the device itself, not
+	 * to the canx netdevice.
+	 */
+	err = pcan_usb_get_serial(dev, &serial_number);
+	if (err) {
+		dev_err(dev->netdev->dev.parent,
+			"unable to read %s serial number (err %d)\n",
+			pcan_usb.name, err);
+		return err;
+	}
+
+	dev_info(dev->netdev->dev.parent,
+		 "PEAK-System %s adapter hwrev %u serial %08X (%u channel)\n",
+		 pcan_usb.name, dev->device_rev, serial_number,
+		 pcan_usb.ctrl_count);
+
+	return 0;
+}
+
+/*
+ * probe function for new PCAN-USB usb interface
+ */
+static int pcan_usb_probe(struct usb_interface *intf)
+{
+	struct usb_host_interface *if_desc;
+	int i;
+
+	if_desc = intf->altsetting;
+
+	/* check interface endpoint addresses */
+	for (i = 0; i < if_desc->desc.bNumEndpoints; i++) {
+		struct usb_endpoint_descriptor *ep = &if_desc->endpoint[i].desc;
+
+		switch (ep->bEndpointAddress) {
+		case PCAN_USB_EP_CMDOUT:
+		case PCAN_USB_EP_CMDIN:
+		case PCAN_USB_EP_MSGOUT:
+		case PCAN_USB_EP_MSGIN:
+			break;
+		default:
+			return -ENODEV;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * describe the PCAN-USB adapter
+ */
+struct peak_usb_adapter pcan_usb = {
+	.name = "PCAN-USB",
+	.device_id = PCAN_USB_PRODUCT_ID,
+	.ctrl_count = 1,
+	.clock = {
+		.freq = PCAN_USB_CRYSTAL_HZ / 2 ,
+	},
+	.bittiming_const = {
+		.name = "pcan_usb",
+		.tseg1_min = 1,
+		.tseg1_max = 16,
+		.tseg2_min = 1,
+		.tseg2_max = 8,
+		.sjw_max = 4,
+		.brp_min = 1,
+		.brp_max = 64,
+		.brp_inc = 1,
+	},
+
+	/* size of device private data */
+	.sizeof_dev_private = sizeof(struct pcan_usb),
+
+	/* timestamps usage */
+	.ts_used_bits = 16,
+	.ts_period = 24575, /* calibration period in ts. */
+	.us_per_ts_scale = PCAN_USB_TS_US_PER_TICK, /* us=(ts*scale) */
+	.us_per_ts_shift = PCAN_USB_TS_DIV_SHIFTER, /*  >> shift     */
+
+	/* give here messages in/out endpoints */
+	.ep_msg_in = PCAN_USB_EP_MSGIN,
+	.ep_msg_out = {PCAN_USB_EP_MSGOUT},
+
+	/* size of rx/tx usb buffers */
+	.rx_buffer_size = PCAN_USB_RX_BUFFER_SIZE,
+	.tx_buffer_size = PCAN_USB_TX_BUFFER_SIZE,
+
+	/* device callbacks */
+	.intf_probe = pcan_usb_probe,
+	.dev_init = pcan_usb_init,
+	.dev_set_bus = pcan_usb_write_mode,
+	.dev_set_bittiming = pcan_usb_set_bittiming,
+	.dev_get_device_id = pcan_usb_get_device_id,
+	.dev_decode_buf = pcan_usb_decode_buf,
+	.dev_encode_msg = pcan_usb_encode_msg,
+	.dev_start = pcan_usb_start,
+	.dev_restart_async = pcan_usb_restart_async,
+};