net/can: add driver for mscan family & mpc52xx_mscan

Taken from socketcan-svn, fixed remaining todos, cleaned up, tested with a
phyCORE-MPC5200B-IO and a custom board.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 699 insertions, 0 deletions

diff --git a/drivers/net/can/mscan/mscan.c b/drivers/net/can/mscan/mscan.c
new file mode 100644
index 00000000000..49542cab9df
--- /dev/null
+++ b/drivers/net/can/mscan/mscan.c
@@ -0,0 +1,699 @@
+/*
+ * CAN bus driver for the alone generic (as possible as) MSCAN controller.
+ *
+ * Copyright (C) 2005-2006 Andrey Volkov <avolkov@varma-el.com>,
+ *                         Varma Electronics Oy
+ * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
+ * Copytight (C) 2008-2009 Pengutronix <kernel@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the version 2 of the GNU General Public License
+ * as published by the Free Software Foundation
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/list.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+#include <linux/io.h>
+
+#include "mscan.h"
+
+#define MSCAN_NORMAL_MODE	0
+#define MSCAN_SLEEP_MODE	MSCAN_SLPRQ
+#define MSCAN_INIT_MODE		(MSCAN_INITRQ | MSCAN_SLPRQ)
+#define MSCAN_POWEROFF_MODE	(MSCAN_CSWAI | MSCAN_SLPRQ)
+#define MSCAN_SET_MODE_RETRIES	255
+#define MSCAN_ECHO_SKB_MAX	3
+
+#define BTR0_BRP_MASK		0x3f
+#define BTR0_SJW_SHIFT		6
+#define BTR0_SJW_MASK		(0x3 << BTR0_SJW_SHIFT)
+
+#define BTR1_TSEG1_MASK 	0xf
+#define BTR1_TSEG2_SHIFT	4
+#define BTR1_TSEG2_MASK 	(0x7 << BTR1_TSEG2_SHIFT)
+#define BTR1_SAM_SHIFT  	7
+
+#define BTR0_SET_BRP(brp)	(((brp) - 1) & BTR0_BRP_MASK)
+#define BTR0_SET_SJW(sjw)	((((sjw) - 1) << BTR0_SJW_SHIFT) & \
+				 BTR0_SJW_MASK)
+
+#define BTR1_SET_TSEG1(tseg1)	(((tseg1) - 1) &  BTR1_TSEG1_MASK)
+#define BTR1_SET_TSEG2(tseg2)	((((tseg2) - 1) << BTR1_TSEG2_SHIFT) & \
+				 BTR1_TSEG2_MASK)
+#define BTR1_SET_SAM(sam)	((sam) ? 1 << BTR1_SAM_SHIFT : 0)
+
+static struct can_bittiming_const mscan_bittiming_const = {
+	.name = "mscan",
+	.tseg1_min = 4,
+	.tseg1_max = 16,
+	.tseg2_min = 2,
+	.tseg2_max = 8,
+	.sjw_max = 4,
+	.brp_min = 1,
+	.brp_max = 64,
+	.brp_inc = 1,
+};
+
+struct mscan_state {
+	u8 mode;
+	u8 canrier;
+	u8 cantier;
+};
+
+#define F_RX_PROGRESS	0
+#define F_TX_PROGRESS	1
+#define F_TX_WAIT_ALL	2
+
+static enum can_state state_map[] = {
+	CAN_STATE_ERROR_ACTIVE,
+	CAN_STATE_ERROR_WARNING,
+	CAN_STATE_ERROR_PASSIVE,
+	CAN_STATE_BUS_OFF
+};
+
+static int mscan_set_mode(struct net_device *dev, u8 mode)
+{
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+	int ret = 0;
+	int i;
+	u8 canctl1;
+
+	if (mode != MSCAN_NORMAL_MODE) {
+
+		if (priv->tx_active) {
+			/* Abort transfers before going to sleep */#
+			out_8(&regs->cantarq, priv->tx_active);
+			/* Suppress TX done interrupts */
+			out_8(&regs->cantier, 0);
+		}
+
+		canctl1 = in_8(&regs->canctl1);
+		if ((mode & MSCAN_SLPRQ) && (canctl1 & MSCAN_SLPAK) == 0) {
+			out_8(&regs->canctl0,
+			      in_8(&regs->canctl0) | MSCAN_SLPRQ);
+			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
+				if (in_8(&regs->canctl1) & MSCAN_SLPAK)
+					break;
+				udelay(100);
+			}
+			/*
+			 * The mscan controller will fail to enter sleep mode,
+			 * while there are irregular activities on bus, like
+			 * somebody keeps retransmitting. This behavior is
+			 * undocumented and seems to differ between mscan built
+			 * in mpc5200b and mpc5200. We proceed in that case,
+			 * since otherwise the slprq will be kept set and the
+			 * controller will get stuck. NOTE: INITRQ or CSWAI
+			 * will abort all active transmit actions, if still
+			 * any, at once.
+			 */
+			if (i >= MSCAN_SET_MODE_RETRIES)
+				dev_dbg(dev->dev.parent,
+					"device failed to enter sleep mode. "
+					"We proceed anyhow.\n");
+			else
+				priv->can.state = CAN_STATE_SLEEPING;
+		}
+
+		if ((mode & MSCAN_INITRQ) && (canctl1 & MSCAN_INITAK) == 0) {
+			out_8(&regs->canctl0,
+			      in_8(&regs->canctl0) | MSCAN_INITRQ);
+			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
+				if (in_8(&regs->canctl1) & MSCAN_INITAK)
+					break;
+			}
+			if (i >= MSCAN_SET_MODE_RETRIES)
+				ret = -ENODEV;
+		}
+		if (!ret)
+			priv->can.state = CAN_STATE_STOPPED;
+
+		if (mode & MSCAN_CSWAI)
+			out_8(&regs->canctl0,
+			      in_8(&regs->canctl0) | MSCAN_CSWAI);
+
+	} else {
+		canctl1 = in_8(&regs->canctl1);
+		if (canctl1 & (MSCAN_SLPAK | MSCAN_INITAK)) {
+			out_8(&regs->canctl0, in_8(&regs->canctl0) &
+			      ~(MSCAN_SLPRQ | MSCAN_INITRQ));
+			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
+				canctl1 = in_8(&regs->canctl1);
+				if (!(canctl1 & (MSCAN_INITAK | MSCAN_SLPAK)))
+					break;
+			}
+			if (i >= MSCAN_SET_MODE_RETRIES)
+				ret = -ENODEV;
+			else
+				priv->can.state = CAN_STATE_ERROR_ACTIVE;
+		}
+	}
+	return ret;
+}
+
+static int mscan_start(struct net_device *dev)
+{
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+	u8 canrflg;
+	int err;
+
+	out_8(&regs->canrier, 0);
+
+	INIT_LIST_HEAD(&priv->tx_head);
+	priv->prev_buf_id = 0;
+	priv->cur_pri = 0;
+	priv->tx_active = 0;
+	priv->shadow_canrier = 0;
+	priv->flags = 0;
+
+	err = mscan_set_mode(dev, MSCAN_NORMAL_MODE);
+	if (err)
+		return err;
+
+	canrflg = in_8(&regs->canrflg);
+	priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
+	priv->can.state = state_map[max(MSCAN_STATE_RX(canrflg),
+				    MSCAN_STATE_TX(canrflg))];
+	out_8(&regs->cantier, 0);
+
+	/* Enable receive interrupts. */
+	out_8(&regs->canrier, MSCAN_OVRIE | MSCAN_RXFIE | MSCAN_CSCIE |
+	      MSCAN_RSTATE1 | MSCAN_RSTATE0 | MSCAN_TSTATE1 | MSCAN_TSTATE0);
+
+	return 0;
+}
+
+static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct can_frame *frame = (struct can_frame *)skb->data;
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+	int i, rtr, buf_id;
+	u32 can_id;
+
+	if (frame->can_dlc > 8)
+		return -EINVAL;
+
+	out_8(&regs->cantier, 0);
+
+	i = ~priv->tx_active & MSCAN_TXE;
+	buf_id = ffs(i) - 1;
+	switch (hweight8(i)) {
+	case 0:
+		netif_stop_queue(dev);
+		dev_err(dev->dev.parent, "Tx Ring full when queue awake!\n");
+		return NETDEV_TX_BUSY;
+	case 1:
+		/*
+		 * if buf_id < 3, then current frame will be send out of order,
+		 * since buffer with lower id have higher priority (hell..)
+		 */
+		netif_stop_queue(dev);
+	case 2:
+		if (buf_id < priv->prev_buf_id) {
+			priv->cur_pri++;
+			if (priv->cur_pri == 0xff) {
+				set_bit(F_TX_WAIT_ALL, &priv->flags);
+				netif_stop_queue(dev);
+			}
+		}
+		set_bit(F_TX_PROGRESS, &priv->flags);
+		break;
+	}
+	priv->prev_buf_id = buf_id;
+	out_8(&regs->cantbsel, i);
+
+	rtr = frame->can_id & CAN_RTR_FLAG;
+
+	if (frame->can_id & CAN_EFF_FLAG) {
+		can_id = (frame->can_id & CAN_EFF_MASK) << 1;
+		if (rtr)
+			can_id |= 1;
+		out_be16(&regs->tx.idr3_2, can_id);
+
+		can_id >>= 16;
+		can_id = (can_id & 0x7) | ((can_id << 2) & 0xffe0) | (3 << 3);
+	} else {
+		can_id = (frame->can_id & CAN_SFF_MASK) << 5;
+		if (rtr)
+			can_id |= 1 << 4;
+	}
+	out_be16(&regs->tx.idr1_0, can_id);
+
+	if (!rtr) {
+		void __iomem *data = &regs->tx.dsr1_0;
+		u16 *payload = (u16 *) frame->data;
+		/* It is safe to write into dsr[dlc+1] */
+		for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
+			out_be16(data, *payload++);
+			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
+		}
+	}
+
+	out_8(&regs->tx.dlr, frame->can_dlc);
+	out_8(&regs->tx.tbpr, priv->cur_pri);
+
+	/* Start transmission. */
+	out_8(&regs->cantflg, 1 << buf_id);
+
+	if (!test_bit(F_TX_PROGRESS, &priv->flags))
+		dev->trans_start = jiffies;
+
+	list_add_tail(&priv->tx_queue[buf_id].list, &priv->tx_head);
+
+	can_put_echo_skb(skb, dev, buf_id);
+
+	/* Enable interrupt. */
+	priv->tx_active |= 1 << buf_id;
+	out_8(&regs->cantier, priv->tx_active);
+
+	return NETDEV_TX_OK;
+}
+
+/* This function returns the old state to see where we came from */
+static enum can_state check_set_state(struct net_device *dev, u8 canrflg)
+{
+	struct mscan_priv *priv = netdev_priv(dev);
+	enum can_state state, old_state = priv->can.state;
+
+	if (canrflg & MSCAN_CSCIF && old_state <= CAN_STATE_BUS_OFF) {
+		state = state_map[max(MSCAN_STATE_RX(canrflg),
+				      MSCAN_STATE_TX(canrflg))];
+		priv->can.state = state;
+	}
+	return old_state;
+}
+
+static void mscan_get_rx_frame(struct net_device *dev, struct can_frame *frame)
+{
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+	u32 can_id;
+	int i;
+
+	can_id = in_be16(&regs->rx.idr1_0);
+	if (can_id & (1 << 3)) {
+		frame->can_id = CAN_EFF_FLAG;
+		can_id = ((can_id << 16) | in_be16(&regs->rx.idr3_2));
+		can_id = ((can_id & 0xffe00000) |
+			  ((can_id & 0x7ffff) << 2)) >> 2;
+	} else {
+		can_id >>= 4;
+		frame->can_id = 0;
+	}
+
+	frame->can_id |= can_id >> 1;
+	if (can_id & 1)
+		frame->can_id |= CAN_RTR_FLAG;
+	frame->can_dlc = in_8(&regs->rx.dlr) & 0xf;
+
+	if (!(frame->can_id & CAN_RTR_FLAG)) {
+		void __iomem *data = &regs->rx.dsr1_0;
+		u16 *payload = (u16 *) frame->data;
+		for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
+			*payload++ = in_be16(data);
+			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
+		}
+	}
+
+	out_8(&regs->canrflg, MSCAN_RXF);
+}
+
+static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame,
+				u8 canrflg)
+{
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+	struct net_device_stats *stats = &dev->stats;
+	enum can_state old_state;
+
+	dev_dbg(dev->dev.parent, "error interrupt (canrflg=%#x)\n", canrflg);
+	frame->can_id = CAN_ERR_FLAG;
+
+	if (canrflg & MSCAN_OVRIF) {
+		frame->can_id |= CAN_ERR_CRTL;
+		frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		stats->rx_over_errors++;
+		stats->rx_errors++;
+	} else
+		frame->data[1] = 0;
+
+	old_state = check_set_state(dev, canrflg);
+	/* State changed */
+	if (old_state != priv->can.state) {
+		switch (priv->can.state) {
+		case CAN_STATE_ERROR_WARNING:
+			frame->can_id |= CAN_ERR_CRTL;
+			priv->can.can_stats.error_warning++;
+			if ((priv->shadow_statflg & MSCAN_RSTAT_MSK) <
+			    (canrflg & MSCAN_RSTAT_MSK))
+				frame->data[1] |= CAN_ERR_CRTL_RX_WARNING;
+
+			if ((priv->shadow_statflg & MSCAN_TSTAT_MSK) <
+			    (canrflg & MSCAN_TSTAT_MSK))
+				frame->data[1] |= CAN_ERR_CRTL_TX_WARNING;
+			break;
+		case CAN_STATE_ERROR_PASSIVE:
+			frame->can_id |= CAN_ERR_CRTL;
+			priv->can.can_stats.error_passive++;
+			frame->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
+			break;
+		case CAN_STATE_BUS_OFF:
+			frame->can_id |= CAN_ERR_BUSOFF;
+			/*
+			 * The MSCAN on the MPC5200 does recover from bus-off
+			 * automatically. To avoid that we stop the chip doing
+			 * a light-weight stop (we are in irq-context).
+			 */
+			out_8(&regs->cantier, 0);
+			out_8(&regs->canrier, 0);
+			out_8(&regs->canctl0, in_8(&regs->canctl0) |
+				MSCAN_SLPRQ | MSCAN_INITRQ);
+			can_bus_off(dev);
+			break;
+		default:
+			break;
+		}
+	}
+	priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
+	frame->can_dlc = CAN_ERR_DLC;
+	out_8(&regs->canrflg, MSCAN_ERR_IF);
+}
+
+static int mscan_rx_poll(struct napi_struct *napi, int quota)
+{
+	struct mscan_priv *priv = container_of(napi, struct mscan_priv, napi);
+	struct net_device *dev = napi->dev;
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+	struct net_device_stats *stats = &dev->stats;
+	int npackets = 0;
+	int ret = 1;
+	struct sk_buff *skb;
+	struct can_frame *frame;
+	u8 canrflg;
+
+	while (npackets < quota && ((canrflg = in_8(&regs->canrflg)) &
+				    (MSCAN_RXF | MSCAN_ERR_IF))) {
+
+		skb = alloc_can_skb(dev, &frame);
+		if (!skb) {
+			if (printk_ratelimit())
+				dev_notice(dev->dev.parent, "packet dropped\n");
+			stats->rx_dropped++;
+			out_8(&regs->canrflg, canrflg);
+			continue;
+		}
+
+		if (canrflg & MSCAN_RXF)
+			mscan_get_rx_frame(dev, frame);
+		 else if (canrflg & MSCAN_ERR_IF)
+			mscan_get_err_frame(dev, frame, canrflg);
+
+		stats->rx_packets++;
+		stats->rx_bytes += frame->can_dlc;
+		npackets++;
+		netif_receive_skb(skb);
+	}
+
+	if (!(in_8(&regs->canrflg) & (MSCAN_RXF | MSCAN_ERR_IF))) {
+		napi_complete(&priv->napi);
+		clear_bit(F_RX_PROGRESS, &priv->flags);
+		if (priv->can.state < CAN_STATE_BUS_OFF)
+			out_8(&regs->canrier, priv->shadow_canrier);
+		ret = 0;
+	}
+	return ret;
+}
+
+static irqreturn_t mscan_isr(int irq, void *dev_id)
+{
+	struct net_device *dev = (struct net_device *)dev_id;
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+	struct net_device_stats *stats = &dev->stats;
+	u8 cantier, cantflg, canrflg;
+	irqreturn_t ret = IRQ_NONE;
+
+	cantier = in_8(&regs->cantier) & MSCAN_TXE;
+	cantflg = in_8(&regs->cantflg) & cantier;
+
+	if (cantier && cantflg) {
+
+		struct list_head *tmp, *pos;
+
+		list_for_each_safe(pos, tmp, &priv->tx_head) {
+			struct tx_queue_entry *entry =
+			    list_entry(pos, struct tx_queue_entry, list);
+			u8 mask = entry->mask;
+
+			if (!(cantflg & mask))
+				continue;
+
+			out_8(&regs->cantbsel, mask);
+			stats->tx_bytes += in_8(&regs->tx.dlr);
+			stats->tx_packets++;
+			can_get_echo_skb(dev, entry->id);
+			priv->tx_active &= ~mask;
+			list_del(pos);
+		}
+
+		if (list_empty(&priv->tx_head)) {
+			clear_bit(F_TX_WAIT_ALL, &priv->flags);
+			clear_bit(F_TX_PROGRESS, &priv->flags);
+			priv->cur_pri = 0;
+		} else
+			dev->trans_start = jiffies;
+
+		if (!test_bit(F_TX_WAIT_ALL, &priv->flags))
+			netif_wake_queue(dev);
+
+		out_8(&regs->cantier, priv->tx_active);
+		ret = IRQ_HANDLED;
+	}
+
+	canrflg = in_8(&regs->canrflg);
+	if ((canrflg & ~MSCAN_STAT_MSK) &&
+	    !test_and_set_bit(F_RX_PROGRESS, &priv->flags)) {
+		if (canrflg & ~MSCAN_STAT_MSK) {
+			priv->shadow_canrier = in_8(&regs->canrier);
+			out_8(&regs->canrier, 0);
+			napi_schedule(&priv->napi);
+			ret = IRQ_HANDLED;
+		} else
+			clear_bit(F_RX_PROGRESS, &priv->flags);
+	}
+	return ret;
+}
+
+static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode)
+{
+
+	struct mscan_priv *priv = netdev_priv(dev);
+	int ret = 0;
+
+	if (!priv->open_time)
+		return -EINVAL;
+
+	switch (mode) {
+	case CAN_MODE_SLEEP:
+	case CAN_MODE_STOP:
+		netif_stop_queue(dev);
+		mscan_set_mode(dev,
+			       (mode ==
+				CAN_MODE_STOP) ? MSCAN_INIT_MODE :
+			       MSCAN_SLEEP_MODE);
+		break;
+	case CAN_MODE_START:
+		if (priv->can.state <= CAN_STATE_BUS_OFF)
+			mscan_set_mode(dev, MSCAN_INIT_MODE);
+		ret = mscan_start(dev);
+		if (ret)
+			break;
+		if (netif_queue_stopped(dev))
+			netif_wake_queue(dev);
+		break;
+
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+	return ret;
+}
+
+static int mscan_do_set_bittiming(struct net_device *dev)
+{
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+	struct can_bittiming *bt = &priv->can.bittiming;
+	u8 btr0, btr1;
+
+	btr0 = BTR0_SET_BRP(bt->brp) | BTR0_SET_SJW(bt->sjw);
+	btr1 = (BTR1_SET_TSEG1(bt->prop_seg + bt->phase_seg1) |
+		BTR1_SET_TSEG2(bt->phase_seg2) |
+		BTR1_SET_SAM(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES));
+
+	dev_info(dev->dev.parent, "setting BTR0=0x%02x BTR1=0x%02x\n",
+		btr0, btr1);
+
+	out_8(&regs->canbtr0, btr0);
+	out_8(&regs->canbtr1, btr1);
+
+	return 0;
+}
+
+static int mscan_open(struct net_device *dev)
+{
+	int ret;
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+
+	/* common open */
+	ret = open_candev(dev);
+	if (ret)
+		return ret;
+
+	napi_enable(&priv->napi);
+
+	ret = request_irq(dev->irq, mscan_isr, 0, dev->name, dev);
+	if (ret < 0) {
+		napi_disable(&priv->napi);
+		printk(KERN_ERR "%s - failed to attach interrupt\n",
+		       dev->name);
+		return ret;
+	}
+
+	priv->open_time = jiffies;
+
+	out_8(&regs->canctl1, in_8(&regs->canctl1) & ~MSCAN_LISTEN);
+
+	ret = mscan_start(dev);
+	if (ret)
+		return ret;
+
+	netif_start_queue(dev);
+
+	return 0;
+}
+
+static int mscan_close(struct net_device *dev)
+{
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+
+	netif_stop_queue(dev);
+	napi_disable(&priv->napi);
+
+	out_8(&regs->cantier, 0);
+	out_8(&regs->canrier, 0);
+	mscan_set_mode(dev, MSCAN_INIT_MODE);
+	close_candev(dev);
+	free_irq(dev->irq, dev);
+	priv->open_time = 0;
+
+	return 0;
+}
+
+static const struct net_device_ops mscan_netdev_ops = {
+       .ndo_open               = mscan_open,
+       .ndo_stop               = mscan_close,
+       .ndo_start_xmit         = mscan_start_xmit,
+};
+
+int register_mscandev(struct net_device *dev, int clock_src)
+{
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+	u8 ctl1;
+
+	ctl1 = in_8(&regs->canctl1);
+	if (clock_src)
+		ctl1 |= MSCAN_CLKSRC;
+	else
+		ctl1 &= ~MSCAN_CLKSRC;
+
+	ctl1 |= MSCAN_CANE;
+	out_8(&regs->canctl1, ctl1);
+	udelay(100);
+
+	/* acceptance mask/acceptance code (accept everything) */
+	out_be16(&regs->canidar1_0, 0);
+	out_be16(&regs->canidar3_2, 0);
+	out_be16(&regs->canidar5_4, 0);
+	out_be16(&regs->canidar7_6, 0);
+
+	out_be16(&regs->canidmr1_0, 0xffff);
+	out_be16(&regs->canidmr3_2, 0xffff);
+	out_be16(&regs->canidmr5_4, 0xffff);
+	out_be16(&regs->canidmr7_6, 0xffff);
+	/* Two 32 bit Acceptance Filters */
+	out_8(&regs->canidac, MSCAN_AF_32BIT);
+
+	mscan_set_mode(dev, MSCAN_INIT_MODE);
+
+	return register_candev(dev);
+}
+EXPORT_SYMBOL_GPL(register_mscandev);
+
+void unregister_mscandev(struct net_device *dev)
+{
+	struct mscan_priv *priv = netdev_priv(dev);
+	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+	mscan_set_mode(dev, MSCAN_INIT_MODE);
+	out_8(&regs->canctl1, in_8(&regs->canctl1) & ~MSCAN_CANE);
+	unregister_candev(dev);
+}
+EXPORT_SYMBOL_GPL(unregister_mscandev);
+
+struct net_device *alloc_mscandev(void)
+{
+	struct net_device *dev;
+	struct mscan_priv *priv;
+	int i;
+
+	dev = alloc_candev(sizeof(struct mscan_priv), MSCAN_ECHO_SKB_MAX);
+	if (!dev)
+		return NULL;
+	priv = netdev_priv(dev);
+
+	dev->netdev_ops = &mscan_netdev_ops;
+
+	dev->flags |= IFF_ECHO;	/* we support local echo */
+
+	netif_napi_add(dev, &priv->napi, mscan_rx_poll, 8);
+
+	priv->can.bittiming_const = &mscan_bittiming_const;
+	priv->can.do_set_bittiming = mscan_do_set_bittiming;
+	priv->can.do_set_mode = mscan_do_set_mode;
+
+	for (i = 0; i < TX_QUEUE_SIZE; i++) {
+		priv->tx_queue[i].id = i;
+		priv->tx_queue[i].mask = 1 << i;
+	}
+
+	return dev;
+}
+EXPORT_SYMBOL_GPL(alloc_mscandev);
+
+MODULE_AUTHOR("Andrey Volkov <avolkov@varma-el.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips");