sja1000.c

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/*
 * sja1000.c -  Philips SJA1000 network device driver
 *
 * Copyright (c) 2003 Matthias Brukner, Trajet Gmbh, Rebenring 33,
 * 38106 Braunschweig, GERMANY
 *
 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of Volkswagen nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * Alternatively, provided that this notice is retained in full, this
 * software may be distributed under the terms of the GNU General
 * Public License ("GPL") version 2, in which case the provisions of the
 * GPL apply INSTEAD OF those given above.
 *
 * The provided data structures and external interfaces from this code
 * are not restricted to be used by modules with a GPL compatible license.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/delay.h>

#include <linux/can/dev.h>
#include <linux/can/error.h>

#include "sja1000.h"

#define DRV_NAME "sja1000"

MODULE_AUTHOR("Oliver Hartkopp <[email protected]>");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION(DRV_NAME "CAN netdevice driver");

static const struct can_bittiming_const sja1000_bittiming_const = {
    .name = DRV_NAME,
    .tseg1_min = 1,
    .tseg1_max = 16,
    .tseg2_min = 1,
    .tseg2_max = 8,
    .sjw_max = 4,
    .brp_min = 1,
    .brp_max = 64,
    .brp_inc = 1,
};

static void sja1000_write_cmdreg(struct sja1000_priv *priv, u8 val)
{
    unsigned long flags;

    /*
     * The command register needs some locking and time to settle
     * the write_reg() operation - especially on SMP systems.
     */
    spin_lock_irqsave(&priv->cmdreg_lock, flags);
    priv->write_reg(priv, REG_CMR, val);
    priv->read_reg(priv, REG_SR);
    spin_unlock_irqrestore(&priv->cmdreg_lock, flags);
}

static int sja1000_is_absent(struct sja1000_priv *priv)
{
    return (priv->read_reg(priv, REG_MOD) == 0xFF);
}

static int sja1000_probe_chip(struct net_device *dev)
{
    struct sja1000_priv *priv = netdev_priv(dev);

    if (priv->reg_base && sja1000_is_absent(priv)) {
        printk(KERN_INFO "%s: probing @0x%lX failed\n",
               DRV_NAME, dev->base_addr);
        return 0;
    }
    return -1;
}

static void set_reset_mode(struct net_device *dev)
{
    struct sja1000_priv *priv = netdev_priv(dev);
    unsigned char status = priv->read_reg(priv, REG_MOD);
    int i;

    /* disable interrupts */
    priv->write_reg(priv, REG_IER, IRQ_OFF);

    for (i = 0; i < 100; i++) {
        /* check reset bit */
        if (status & MOD_RM) {
            priv->can.state = CAN_STATE_STOPPED;
            return;
        }

        priv->write_reg(priv, REG_MOD, MOD_RM); /* reset chip */
        udelay(10);
        status = priv->read_reg(priv, REG_MOD);
    }

    netdev_err(dev, "setting SJA1000 into reset mode failed!\n");
}

static void set_normal_mode(struct net_device *dev)
{
    struct sja1000_priv *priv = netdev_priv(dev);
    unsigned char status = priv->read_reg(priv, REG_MOD);
    int i;

    for (i = 0; i < 100; i++) {
        /* check reset bit */
        if ((status & MOD_RM) == 0) {
            priv->can.state = CAN_STATE_ERROR_ACTIVE;
            /* enable interrupts */
            if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
                priv->write_reg(priv, REG_IER, IRQ_ALL);
            else
                priv->write_reg(priv, REG_IER,
                        IRQ_ALL & ~IRQ_BEI);
            return;
        }

        /* set chip to normal mode */
        if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
            priv->write_reg(priv, REG_MOD, MOD_LOM);
        else
            priv->write_reg(priv, REG_MOD, 0x00);

        udelay(10);

        status = priv->read_reg(priv, REG_MOD);
    }

    netdev_err(dev, "setting SJA1000 into normal mode failed!\n");
}

static void sja1000_start(struct net_device *dev)
{
    struct sja1000_priv *priv = netdev_priv(dev);

    /* leave reset mode */
    if (priv->can.state != CAN_STATE_STOPPED)
        set_reset_mode(dev);

    /* Clear error counters and error code capture */
    priv->write_reg(priv, REG_TXERR, 0x0);
    priv->write_reg(priv, REG_RXERR, 0x0);
    priv->read_reg(priv, REG_ECC);

    /* leave reset mode */
    set_normal_mode(dev);
}

static int sja1000_set_mode(struct net_device *dev, enum can_mode mode)
{
    struct sja1000_priv *priv = netdev_priv(dev);

    if (!priv->open_time)
        return -EINVAL;

    switch (mode) {
    case CAN_MODE_START:
        sja1000_start(dev);
        if (netif_queue_stopped(dev))
            netif_wake_queue(dev);
        break;

    default:
        return -EOPNOTSUPP;
    }

    return 0;
}

static int sja1000_set_bittiming(struct net_device *dev)
{
    struct sja1000_priv *priv = netdev_priv(dev);
    struct can_bittiming *bt = &priv->can.bittiming;
    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 (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
        btr1 |= 0x80;

    netdev_info(dev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);

    priv->write_reg(priv, REG_BTR0, btr0);
    priv->write_reg(priv, REG_BTR1, btr1);

    return 0;
}

static int sja1000_get_berr_counter(const struct net_device *dev,
                    struct can_berr_counter *bec)
{
    struct sja1000_priv *priv = netdev_priv(dev);

    bec->txerr = priv->read_reg(priv, REG_TXERR);
    bec->rxerr = priv->read_reg(priv, REG_RXERR);

    return 0;
}

/*
 * initialize SJA1000 chip:
 *   - reset chip
 *   - set output mode
 *   - set baudrate
 *   - enable interrupts
 *   - start operating mode
 */
static void chipset_init(struct net_device *dev)
{
    struct sja1000_priv *priv = netdev_priv(dev);

    /* set clock divider and output control register */
    priv->write_reg(priv, REG_CDR, priv->cdr | CDR_PELICAN);

    /* set acceptance filter (accept all) */
    priv->write_reg(priv, REG_ACCC0, 0x00);
    priv->write_reg(priv, REG_ACCC1, 0x00);
    priv->write_reg(priv, REG_ACCC2, 0x00);
    priv->write_reg(priv, REG_ACCC3, 0x00);

    priv->write_reg(priv, REG_ACCM0, 0xFF);
    priv->write_reg(priv, REG_ACCM1, 0xFF);
    priv->write_reg(priv, REG_ACCM2, 0xFF);
    priv->write_reg(priv, REG_ACCM3, 0xFF);

    priv->write_reg(priv, REG_OCR, priv->ocr | OCR_MODE_NORMAL);
}

/*
 * transmit a CAN message
 * message layout in the sk_buff should be like this:
 * xx xx xx xx   ff  ll   00 11 22 33 44 55 66 77
 * [  can-id ] [flags] [len] [can data (up to 8 bytes]
 */
static netdev_tx_t sja1000_start_xmit(struct sk_buff *skb,
                        struct net_device *dev)
{
    struct sja1000_priv *priv = netdev_priv(dev);
    struct can_frame *cf = (struct can_frame *)skb->data;
    uint8_t fi;
    uint8_t dlc;
    canid_t id;
    uint8_t dreg;
    int i;

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

    netif_stop_queue(dev);

    fi = dlc = cf->can_dlc;
    id = cf->can_id;

    if (id & CAN_RTR_FLAG)
        fi |= FI_RTR;

    if (id & CAN_EFF_FLAG) {
        fi |= FI_FF;
        dreg = EFF_BUF;
        priv->write_reg(priv, REG_FI, fi);
        priv->write_reg(priv, REG_ID1, (id & 0x1fe00000) >> (5 + 16));
        priv->write_reg(priv, REG_ID2, (id & 0x001fe000) >> (5 + 8));
        priv->write_reg(priv, REG_ID3, (id & 0x00001fe0) >> 5);
        priv->write_reg(priv, REG_ID4, (id & 0x0000001f) << 3);
    } else {
        dreg = SFF_BUF;
        priv->write_reg(priv, REG_FI, fi);
        priv->write_reg(priv, REG_ID1, (id & 0x000007f8) >> 3);
        priv->write_reg(priv, REG_ID2, (id & 0x00000007) << 5);
    }

    for (i = 0; i < dlc; i++)
        priv->write_reg(priv, dreg++, cf->data[i]);

    can_put_echo_skb(skb, dev, 0);

    if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
        sja1000_write_cmdreg(priv, CMD_TR | CMD_AT);
    else
        sja1000_write_cmdreg(priv, CMD_TR);

    return NETDEV_TX_OK;
}

static void sja1000_rx(struct net_device *dev)
{
    struct sja1000_priv *priv = netdev_priv(dev);
    struct net_device_stats *stats = &dev->stats;
    struct can_frame *cf;
    struct sk_buff *skb;
    uint8_t fi;
    uint8_t dreg;
    canid_t id;
    int i;

    /* create zero'ed CAN frame buffer */
    skb = alloc_can_skb(dev, &cf);
    if (skb == NULL)
        return;

    fi = priv->read_reg(priv, REG_FI);

    if (fi & FI_FF) {
        /* extended frame format (EFF) */
        dreg = EFF_BUF;
        id = (priv->read_reg(priv, REG_ID1) << (5 + 16))
            | (priv->read_reg(priv, REG_ID2) << (5 + 8))
            | (priv->read_reg(priv, REG_ID3) << 5)
            | (priv->read_reg(priv, REG_ID4) >> 3);
        id |= CAN_EFF_FLAG;
    } else {
        /* standard frame format (SFF) */
        dreg = SFF_BUF;
        id = (priv->read_reg(priv, REG_ID1) << 3)
            | (priv->read_reg(priv, REG_ID2) >> 5);
    }

    cf->can_dlc = get_can_dlc(fi & 0x0F);
    if (fi & FI_RTR) {
        id |= CAN_RTR_FLAG;
    } else {
        for (i = 0; i < cf->can_dlc; i++)
            cf->data[i] = priv->read_reg(priv, dreg++);
    }

    cf->can_id = id;

    /* release receive buffer */
    sja1000_write_cmdreg(priv, CMD_RRB);

    netif_rx(skb);

    stats->rx_packets++;
    stats->rx_bytes += cf->can_dlc;
}

static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
{
    struct sja1000_priv *priv = netdev_priv(dev);
    struct net_device_stats *stats = &dev->stats;
    struct can_frame *cf;
    struct sk_buff *skb;
    enum can_state state = priv->can.state;
    uint8_t ecc, alc;

    skb = alloc_can_err_skb(dev, &cf);
    if (skb == NULL)
        return -ENOMEM;

    if (isrc & IRQ_DOI) {
        /* data overrun interrupt */
        netdev_dbg(dev, "data overrun interrupt\n");
        cf->can_id |= CAN_ERR_CRTL;
        cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
        stats->rx_over_errors++;
        stats->rx_errors++;
        sja1000_write_cmdreg(priv, CMD_CDO);    /* clear bit */
    }

    if (isrc & IRQ_EI) {
        /* error warning interrupt */
        netdev_dbg(dev, "error warning interrupt\n");

        if (status & SR_BS) {
            state = CAN_STATE_BUS_OFF;
            cf->can_id |= CAN_ERR_BUSOFF;
            can_bus_off(dev);
        } else if (status & SR_ES) {
            state = CAN_STATE_ERROR_WARNING;
        } else
            state = CAN_STATE_ERROR_ACTIVE;
    }
    if (isrc & IRQ_BEI) {
        /* bus error interrupt */
        priv->can.can_stats.bus_error++;
        stats->rx_errors++;

        ecc = priv->read_reg(priv, REG_ECC);

        cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;

        switch (ecc & ECC_MASK) {
        case ECC_BIT:
            cf->data[2] |= CAN_ERR_PROT_BIT;
            break;
        case ECC_FORM:
            cf->data[2] |= CAN_ERR_PROT_FORM;
            break;
        case ECC_STUFF:
            cf->data[2] |= CAN_ERR_PROT_STUFF;
            break;
        default:
            cf->data[2] |= CAN_ERR_PROT_UNSPEC;
            cf->data[3] = ecc & ECC_SEG;
            break;
        }
        /* Error occurred during transmission? */
        if ((ecc & ECC_DIR) == 0)
            cf->data[2] |= CAN_ERR_PROT_TX;
    }
    if (isrc & IRQ_EPI) {
        /* error passive interrupt */
        netdev_dbg(dev, "error passive interrupt\n");
        if (status & SR_ES)
            state = CAN_STATE_ERROR_PASSIVE;
        else
            state = CAN_STATE_ERROR_ACTIVE;
    }
    if (isrc & IRQ_ALI) {
        /* arbitration lost interrupt */
        netdev_dbg(dev, "arbitration lost interrupt\n");
        alc = priv->read_reg(priv, REG_ALC);
        priv->can.can_stats.arbitration_lost++;
        stats->tx_errors++;
        cf->can_id |= CAN_ERR_LOSTARB;
        cf->data[0] = alc & 0x1f;
    }

    if (state != priv->can.state && (state == CAN_STATE_ERROR_WARNING ||
                     state == CAN_STATE_ERROR_PASSIVE)) {
        uint8_t rxerr = priv->read_reg(priv, REG_RXERR);
        uint8_t txerr = priv->read_reg(priv, REG_TXERR);
        cf->can_id |= CAN_ERR_CRTL;
        if (state == CAN_STATE_ERROR_WARNING) {
            priv->can.can_stats.error_warning++;
            cf->data[1] = (txerr > rxerr) ?
                CAN_ERR_CRTL_TX_WARNING :
                CAN_ERR_CRTL_RX_WARNING;
        } else {
            priv->can.can_stats.error_passive++;
            cf->data[1] = (txerr > rxerr) ?
                CAN_ERR_CRTL_TX_PASSIVE :
                CAN_ERR_CRTL_RX_PASSIVE;
        }
        cf->data[6] = txerr;
        cf->data[7] = rxerr;
    }

    priv->can.state = state;

    netif_rx(skb);

    stats->rx_packets++;
    stats->rx_bytes += cf->can_dlc;

    return 0;
}

irqreturn_t sja1000_interrupt(int irq, void *dev_id)
{
    struct net_device *dev = (struct net_device *)dev_id;
    struct sja1000_priv *priv = netdev_priv(dev);
    struct net_device_stats *stats = &dev->stats;
    uint8_t isrc, status;
    int n = 0;

    /* Shared interrupts and IRQ off? */
    if (priv->read_reg(priv, REG_IER) == IRQ_OFF)
        return IRQ_NONE;

    if (priv->pre_irq)
        priv->pre_irq(priv);

    while ((isrc = priv->read_reg(priv, REG_IR)) && (n < SJA1000_MAX_IRQ)) {
        n++;
        status = priv->read_reg(priv, REG_SR);
        /* check for absent controller due to hw unplug */
        if (status == 0xFF && sja1000_is_absent(priv))
            return IRQ_NONE;

        if (isrc & IRQ_WUI)
            netdev_warn(dev, "wakeup interrupt\n");

        if (isrc & IRQ_TI) {
            /* transmission buffer released */
            if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT &&
                !(status & SR_TCS)) {
                stats->tx_errors++;
                can_free_echo_skb(dev, 0);
            } else {
                /* transmission complete */
                stats->tx_bytes +=
                    priv->read_reg(priv, REG_FI) & 0xf;
                stats->tx_packets++;
                can_get_echo_skb(dev, 0);
            }
            netif_wake_queue(dev);
        }
        if (isrc & IRQ_RI) {
            /* receive interrupt */
            while (status & SR_RBS) {
                sja1000_rx(dev);
                status = priv->read_reg(priv, REG_SR);
                /* check for absent controller */
                if (status == 0xFF && sja1000_is_absent(priv))
                    return IRQ_NONE;
            }
        }
        if (isrc & (IRQ_DOI | IRQ_EI | IRQ_BEI | IRQ_EPI | IRQ_ALI)) {
            /* error interrupt */
            if (sja1000_err(dev, isrc, status))
                break;
        }
    }

    if (priv->post_irq)
        priv->post_irq(priv);

    if (n >= SJA1000_MAX_IRQ)
        netdev_dbg(dev, "%d messages handled in ISR", n);

    return (n) ? IRQ_HANDLED : IRQ_NONE;
}
EXPORT_SYMBOL_GPL(sja1000_interrupt);

static int sja1000_open(struct net_device *dev)
{
    struct sja1000_priv *priv = netdev_priv(dev);
    int err;

    /* set chip into reset mode */
    set_reset_mode(dev);

    /* common open */
    err = open_candev(dev);
    if (err)
        return err;

    /* register interrupt handler, if not done by the device driver */
    if (!(priv->flags & SJA1000_CUSTOM_IRQ_HANDLER)) {
        err = request_irq(dev->irq, sja1000_interrupt, priv->irq_flags,
                  dev->name, (void *)dev);
        if (err) {
            close_candev(dev);
            return -EAGAIN;
        }
    }

    /* init and start chi */
    sja1000_start(dev);
    priv->open_time = jiffies;

    netif_start_queue(dev);

    return 0;
}

static int sja1000_close(struct net_device *dev)
{
    struct sja1000_priv *priv = netdev_priv(dev);

    netif_stop_queue(dev);
    set_reset_mode(dev);

    if (!(priv->flags & SJA1000_CUSTOM_IRQ_HANDLER))
        free_irq(dev->irq, (void *)dev);

    close_candev(dev);

    priv->open_time = 0;

    return 0;
}

struct net_device *alloc_sja1000dev(int sizeof_priv)
{
    struct net_device *dev;
    struct sja1000_priv *priv;

    dev = alloc_candev(sizeof(struct sja1000_priv) + sizeof_priv,
        SJA1000_ECHO_SKB_MAX);
    if (!dev)
        return NULL;

    priv = netdev_priv(dev);

    priv->dev = dev;
    priv->can.bittiming_const = &sja1000_bittiming_const;
    priv->can.do_set_bittiming = sja1000_set_bittiming;
    priv->can.do_set_mode = sja1000_set_mode;
    priv->can.do_get_berr_counter = sja1000_get_berr_counter;
    priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
        CAN_CTRLMODE_BERR_REPORTING | CAN_CTRLMODE_LISTENONLY |
        CAN_CTRLMODE_ONE_SHOT;

    spin_lock_init(&priv->cmdreg_lock);

    if (sizeof_priv)
        priv->priv = (void *)priv + sizeof(struct sja1000_priv);

    return dev;
}
EXPORT_SYMBOL_GPL(alloc_sja1000dev);

void free_sja1000dev(struct net_device *dev)
{
    free_candev(dev);
}
EXPORT_SYMBOL_GPL(free_sja1000dev);

static const struct net_device_ops sja1000_netdev_ops = {
       .ndo_open               = sja1000_open,
       .ndo_stop               = sja1000_close,
       .ndo_start_xmit         = sja1000_start_xmit,
};

int register_sja1000dev(struct net_device *dev)
{
    if (!sja1000_probe_chip(dev))
        return -ENODEV;

    dev->flags |= IFF_ECHO; /* we support local echo */
    dev->netdev_ops = &sja1000_netdev_ops;

    set_reset_mode(dev);
    chipset_init(dev);

    return register_candev(dev);
}
EXPORT_SYMBOL_GPL(register_sja1000dev);

void unregister_sja1000dev(struct net_device *dev)
{
    set_reset_mode(dev);
    unregister_candev(dev);
}
EXPORT_SYMBOL_GPL(unregister_sja1000dev);

static __init int sja1000_init(void)
{
    printk(KERN_INFO "%s CAN netdevice driver\n", DRV_NAME);

    return 0;
}

module_init(sja1000_init);

static __exit void sja1000_exit(void)
{
    printk(KERN_INFO "%s: driver removed\n", DRV_NAME);
}

module_exit(sja1000_exit);