mscan.c

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/*
 * CAN bus driver for the alone generic (as possible as) MSCAN controller.
 *
 * Copyright (C) 2005-2006 Andrey Volkov <[email protected]>,
 *                         Varma Electronics Oy
 * Copyright (C) 2008-2009 Wolfgang Grandegger <[email protected]>
 * Copyright (C) 2008-2009 Pengutronix <[email protected]>
 *
 * 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/dev.h>
#include <linux/can/error.h>
#include <linux/io.h>

#include "mscan.h"

static const 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;
};

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 __iomem *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)) {
            setbits8(&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)
                netdev_dbg(dev,
                       "device failed to enter sleep mode. "
                       "We proceed anyhow.\n");
            else
                priv->can.state = CAN_STATE_SLEEPING;
        }

        if ((mode & MSCAN_INITRQ) && !(canctl1 & MSCAN_INITAK)) {
            setbits8(&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)
            setbits8(&regs->canctl0, MSCAN_CSWAI);

    } else {
        canctl1 = in_8(&regs->canctl1);
        if (canctl1 & (MSCAN_SLPAK | MSCAN_INITAK)) {
            clrbits8(&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 __iomem *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;

    if (priv->type == MSCAN_TYPE_MPC5121) {
        /* Clear pending bus-off condition */
        if (in_8(&regs->canmisc) & MSCAN_BOHOLD)
            out_8(&regs->canmisc, MSCAN_BOHOLD);
    }

    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_RX_INTS_ENABLE);

    return 0;
}

static int mscan_restart(struct net_device *dev)
{
    struct mscan_priv *priv = netdev_priv(dev);

    if (priv->type == MSCAN_TYPE_MPC5121) {
        struct mscan_regs __iomem *regs = priv->reg_base;

        priv->can.state = CAN_STATE_ERROR_ACTIVE;
        WARN(!(in_8(&regs->canmisc) & MSCAN_BOHOLD),
             "bus-off state expected\n");
        out_8(&regs->canmisc, MSCAN_BOHOLD);
        /* Re-enable receive interrupts. */
        out_8(&regs->canrier, MSCAN_RX_INTS_ENABLE);
    } else {
        if (priv->can.state <= CAN_STATE_BUS_OFF)
            mscan_set_mode(dev, MSCAN_INIT_MODE);
        return mscan_start(dev);
    }

    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 __iomem *regs = priv->reg_base;
    int i, rtr, buf_id;
    u32 can_id;

    if (can_dropped_invalid_skb(dev, skb))
        return NETDEV_TX_OK;

    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);
        netdev_err(dev, "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;

    /* RTR is always the lowest bit of interest, then IDs follow */
    if (frame->can_id & CAN_EFF_FLAG) {
        can_id = (frame->can_id & CAN_EFF_MASK)
             << (MSCAN_EFF_RTR_SHIFT + 1);
        if (rtr)
            can_id |= 1 << MSCAN_EFF_RTR_SHIFT;
        out_be16(&regs->tx.idr3_2, can_id);

        can_id >>= 16;
        /* EFF_FLAGS are between the IDs :( */
        can_id = (can_id & 0x7) | ((can_id << 2) & 0xffe0)
             | MSCAN_EFF_FLAGS;
    } else {
        can_id = (frame->can_id & CAN_SFF_MASK)
             << (MSCAN_SFF_RTR_SHIFT + 1);
        if (rtr)
            can_id |= 1 << MSCAN_SFF_RTR_SHIFT;
    }
    out_be16(&regs->tx.idr1_0, can_id);

    if (!rtr) {
        void __iomem *data = &regs->tx.dsr1_0;
        u16 *payload = (u16 *)frame->data;

        for (i = 0; i < frame->can_dlc / 2; i++) {
            out_be16(data, *payload++);
            data += 2 + _MSCAN_RESERVED_DSR_SIZE;
        }
        /* write remaining byte if necessary */
        if (frame->can_dlc & 1)
            out_8(data, frame->data[frame->can_dlc - 1]);
    }

    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 __iomem *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 = get_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 / 2; i++) {
            *payload++ = in_be16(data);
            data += 2 + _MSCAN_RESERVED_DSR_SIZE;
        }
        /* read remaining byte if necessary */
        if (frame->can_dlc & 1)
            frame->data[frame->can_dlc - 1] = in_8(data);
    }

    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 __iomem *regs = priv->reg_base;
    struct net_device_stats *stats = &dev->stats;
    enum can_state old_state;

    netdev_dbg(dev, "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).
             */
            if (priv->type != MSCAN_TYPE_MPC5121) {
                out_8(&regs->cantier, 0);
                out_8(&regs->canrier, 0);
                setbits8(&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 __iomem *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);
        if (!(canrflg & (MSCAN_RXF | MSCAN_ERR_IF)))
            break;

        skb = alloc_can_skb(dev, &frame);
        if (!skb) {
            if (printk_ratelimit())
                netdev_notice(dev, "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 __iomem *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_START:
        ret = mscan_restart(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 __iomem *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));

    netdev_info(dev, "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_get_berr_counter(const struct net_device *dev,
                  struct can_berr_counter *bec)
{
    struct mscan_priv *priv = netdev_priv(dev);
    struct mscan_regs __iomem *regs = priv->reg_base;

    bec->txerr = in_8(&regs->cantxerr);
    bec->rxerr = in_8(&regs->canrxerr);

    return 0;
}

static int mscan_open(struct net_device *dev)
{
    int ret;
    struct mscan_priv *priv = netdev_priv(dev);
    struct mscan_regs __iomem *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) {
        netdev_err(dev, "failed to attach interrupt\n");
        goto exit_napi_disable;
    }

    priv->open_time = jiffies;

    if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
        setbits8(&regs->canctl1, MSCAN_LISTEN);
    else
        clrbits8(&regs->canctl1, MSCAN_LISTEN);

    ret = mscan_start(dev);
    if (ret)
        goto exit_free_irq;

    netif_start_queue(dev);

    return 0;

exit_free_irq:
    priv->open_time = 0;
    free_irq(dev->irq, dev);
exit_napi_disable:
    napi_disable(&priv->napi);
    close_candev(dev);
    return ret;
}

static int mscan_close(struct net_device *dev)
{
    struct mscan_priv *priv = netdev_priv(dev);
    struct mscan_regs __iomem *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 mscan_clksrc)
{
    struct mscan_priv *priv = netdev_priv(dev);
    struct mscan_regs __iomem *regs = priv->reg_base;
    u8 ctl1;

    ctl1 = in_8(&regs->canctl1);
    if (mscan_clksrc)
        ctl1 |= MSCAN_CLKSRC;
    else
        ctl1 &= ~MSCAN_CLKSRC;

    if (priv->type == MSCAN_TYPE_MPC5121) {
        priv->can.do_get_berr_counter = mscan_get_berr_counter;
        ctl1 |= MSCAN_BORM; /* bus-off recovery upon request */
    }

    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);
}

void unregister_mscandev(struct net_device *dev)
{
    struct mscan_priv *priv = netdev_priv(dev);
    struct mscan_regs __iomem *regs = priv->reg_base;
    mscan_set_mode(dev, MSCAN_INIT_MODE);
    clrbits8(&regs->canctl1, MSCAN_CANE);
    unregister_candev(dev);
}

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;
    priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
        CAN_CTRLMODE_LISTENONLY;

    for (i = 0; i < TX_QUEUE_SIZE; i++) {
        priv->tx_queue[i].id = i;
        priv->tx_queue[i].mask = 1 << i;
    }

    return dev;
}

MODULE_AUTHOR("Andrey Volkov <[email protected]>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips");