softing_main.c

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/*
 * Copyright (C) 2008-2010
 *
 * - Kurt Van Dijck, EIA Electronics
 *
 * 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/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <asm/io.h>

#include "softing.h"

#define TX_ECHO_SKB_MAX (((TXMAX+1)/2)-1)

/*
 * test is a specific CAN netdev
 * is online (ie. up 'n running, not sleeping, not busoff
 */
static inline int canif_is_active(struct net_device *netdev)
{
    struct can_priv *can = netdev_priv(netdev);

    if (!netif_running(netdev))
        return 0;
    return (can->state <= CAN_STATE_ERROR_PASSIVE);
}

/* reset DPRAM */
static inline void softing_set_reset_dpram(struct softing *card)
{
    if (card->pdat->generation >= 2) {
        spin_lock_bh(&card->spin);
        iowrite8(ioread8(&card->dpram[DPRAM_V2_RESET]) & ~1,
                &card->dpram[DPRAM_V2_RESET]);
        spin_unlock_bh(&card->spin);
    }
}

static inline void softing_clr_reset_dpram(struct softing *card)
{
    if (card->pdat->generation >= 2) {
        spin_lock_bh(&card->spin);
        iowrite8(ioread8(&card->dpram[DPRAM_V2_RESET]) | 1,
                &card->dpram[DPRAM_V2_RESET]);
        spin_unlock_bh(&card->spin);
    }
}

/* trigger the tx queue-ing */
static netdev_tx_t softing_netdev_start_xmit(struct sk_buff *skb,
        struct net_device *dev)
{
    struct softing_priv *priv = netdev_priv(dev);
    struct softing *card = priv->card;
    int ret;
    uint8_t *ptr;
    uint8_t fifo_wr, fifo_rd;
    struct can_frame *cf = (struct can_frame *)skb->data;
    uint8_t buf[DPRAM_TX_SIZE];

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

    spin_lock(&card->spin);

    ret = NETDEV_TX_BUSY;
    if (!card->fw.up ||
            (card->tx.pending >= TXMAX) ||
            (priv->tx.pending >= TX_ECHO_SKB_MAX))
        goto xmit_done;
    fifo_wr = ioread8(&card->dpram[DPRAM_TX_WR]);
    fifo_rd = ioread8(&card->dpram[DPRAM_TX_RD]);
    if (fifo_wr == fifo_rd)
        /* fifo full */
        goto xmit_done;
    memset(buf, 0, sizeof(buf));
    ptr = buf;
    *ptr = CMD_TX;
    if (cf->can_id & CAN_RTR_FLAG)
        *ptr |= CMD_RTR;
    if (cf->can_id & CAN_EFF_FLAG)
        *ptr |= CMD_XTD;
    if (priv->index)
        *ptr |= CMD_BUS2;
    ++ptr;
    *ptr++ = cf->can_dlc;
    *ptr++ = (cf->can_id >> 0);
    *ptr++ = (cf->can_id >> 8);
    if (cf->can_id & CAN_EFF_FLAG) {
        *ptr++ = (cf->can_id >> 16);
        *ptr++ = (cf->can_id >> 24);
    } else {
        /* increment 1, not 2 as you might think */
        ptr += 1;
    }
    if (!(cf->can_id & CAN_RTR_FLAG))
        memcpy(ptr, &cf->data[0], cf->can_dlc);
    memcpy_toio(&card->dpram[DPRAM_TX + DPRAM_TX_SIZE * fifo_wr],
            buf, DPRAM_TX_SIZE);
    if (++fifo_wr >= DPRAM_TX_CNT)
        fifo_wr = 0;
    iowrite8(fifo_wr, &card->dpram[DPRAM_TX_WR]);
    card->tx.last_bus = priv->index;
    ++card->tx.pending;
    ++priv->tx.pending;
    can_put_echo_skb(skb, dev, priv->tx.echo_put);
    ++priv->tx.echo_put;
    if (priv->tx.echo_put >= TX_ECHO_SKB_MAX)
        priv->tx.echo_put = 0;
    /* can_put_echo_skb() saves the skb, safe to return TX_OK */
    ret = NETDEV_TX_OK;
xmit_done:
    spin_unlock(&card->spin);
    if (card->tx.pending >= TXMAX) {
        int j;
        for (j = 0; j < ARRAY_SIZE(card->net); ++j) {
            if (card->net[j])
                netif_stop_queue(card->net[j]);
        }
    }
    if (ret != NETDEV_TX_OK)
        netif_stop_queue(dev);

    return ret;
}

/*
 * shortcut for skb delivery
 */
int softing_netdev_rx(struct net_device *netdev, const struct can_frame *msg,
        ktime_t ktime)
{
    struct sk_buff *skb;
    struct can_frame *cf;

    skb = alloc_can_skb(netdev, &cf);
    if (!skb)
        return -ENOMEM;
    memcpy(cf, msg, sizeof(*msg));
    skb->tstamp = ktime;
    return netif_rx(skb);
}

/*
 * softing_handle_1
 * pop 1 entry from the DPRAM queue, and process
 */
static int softing_handle_1(struct softing *card)
{
    struct net_device *netdev;
    struct softing_priv *priv;
    ktime_t ktime;
    struct can_frame msg;
    int cnt = 0, lost_msg;
    uint8_t fifo_rd, fifo_wr, cmd;
    uint8_t *ptr;
    uint32_t tmp_u32;
    uint8_t buf[DPRAM_RX_SIZE];

    memset(&msg, 0, sizeof(msg));
    /* test for lost msgs */
    lost_msg = ioread8(&card->dpram[DPRAM_RX_LOST]);
    if (lost_msg) {
        int j;
        /* reset condition */
        iowrite8(0, &card->dpram[DPRAM_RX_LOST]);
        /* prepare msg */
        msg.can_id = CAN_ERR_FLAG | CAN_ERR_CRTL;
        msg.can_dlc = CAN_ERR_DLC;
        msg.data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
        /*
         * service to all busses, we don't know which it was applicable
         * but only service busses that are online
         */
        for (j = 0; j < ARRAY_SIZE(card->net); ++j) {
            netdev = card->net[j];
            if (!netdev)
                continue;
            if (!canif_is_active(netdev))
                /* a dead bus has no overflows */
                continue;
            ++netdev->stats.rx_over_errors;
            softing_netdev_rx(netdev, &msg, ktime_set(0, 0));
        }
        /* prepare for other use */
        memset(&msg, 0, sizeof(msg));
        ++cnt;
    }

    fifo_rd = ioread8(&card->dpram[DPRAM_RX_RD]);
    fifo_wr = ioread8(&card->dpram[DPRAM_RX_WR]);

    if (++fifo_rd >= DPRAM_RX_CNT)
        fifo_rd = 0;
    if (fifo_wr == fifo_rd)
        return cnt;

    memcpy_fromio(buf, &card->dpram[DPRAM_RX + DPRAM_RX_SIZE*fifo_rd],
            DPRAM_RX_SIZE);
    mb();
    /* trigger dual port RAM */
    iowrite8(fifo_rd, &card->dpram[DPRAM_RX_RD]);

    ptr = buf;
    cmd = *ptr++;
    if (cmd == 0xff)
        /* not quite useful, probably the card has got out */
        return 0;
    netdev = card->net[0];
    if (cmd & CMD_BUS2)
        netdev = card->net[1];
    priv = netdev_priv(netdev);

    if (cmd & CMD_ERR) {
        uint8_t can_state, state;

        state = *ptr++;

        msg.can_id = CAN_ERR_FLAG;
        msg.can_dlc = CAN_ERR_DLC;

        if (state & SF_MASK_BUSOFF) {
            can_state = CAN_STATE_BUS_OFF;
            msg.can_id |= CAN_ERR_BUSOFF;
            state = STATE_BUSOFF;
        } else if (state & SF_MASK_EPASSIVE) {
            can_state = CAN_STATE_ERROR_PASSIVE;
            msg.can_id |= CAN_ERR_CRTL;
            msg.data[1] = CAN_ERR_CRTL_TX_PASSIVE;
            state = STATE_EPASSIVE;
        } else {
            can_state = CAN_STATE_ERROR_ACTIVE;
            msg.can_id |= CAN_ERR_CRTL;
            state = STATE_EACTIVE;
        }
        /* update DPRAM */
        iowrite8(state, &card->dpram[priv->index ?
                DPRAM_INFO_BUSSTATE2 : DPRAM_INFO_BUSSTATE]);
        /* timestamp */
        tmp_u32 = le32_to_cpup((void *)ptr);
        ptr += 4;
        ktime = softing_raw2ktime(card, tmp_u32);

        ++netdev->stats.rx_errors;
        /* update internal status */
        if (can_state != priv->can.state) {
            priv->can.state = can_state;
            if (can_state == CAN_STATE_ERROR_PASSIVE)
                ++priv->can.can_stats.error_passive;
            else if (can_state == CAN_STATE_BUS_OFF) {
                /* this calls can_close_cleanup() */
                can_bus_off(netdev);
                netif_stop_queue(netdev);
            }
            /* trigger socketcan */
            softing_netdev_rx(netdev, &msg, ktime);
        }

    } else {
        if (cmd & CMD_RTR)
            msg.can_id |= CAN_RTR_FLAG;
        msg.can_dlc = get_can_dlc(*ptr++);
        if (cmd & CMD_XTD) {
            msg.can_id |= CAN_EFF_FLAG;
            msg.can_id |= le32_to_cpup((void *)ptr);
            ptr += 4;
        } else {
            msg.can_id |= le16_to_cpup((void *)ptr);
            ptr += 2;
        }
        /* timestamp */
        tmp_u32 = le32_to_cpup((void *)ptr);
        ptr += 4;
        ktime = softing_raw2ktime(card, tmp_u32);
        if (!(msg.can_id & CAN_RTR_FLAG))
            memcpy(&msg.data[0], ptr, 8);
        ptr += 8;
        /* update socket */
        if (cmd & CMD_ACK) {
            /* acknowledge, was tx msg */
            struct sk_buff *skb;
            skb = priv->can.echo_skb[priv->tx.echo_get];
            if (skb)
                skb->tstamp = ktime;
            can_get_echo_skb(netdev, priv->tx.echo_get);
            ++priv->tx.echo_get;
            if (priv->tx.echo_get >= TX_ECHO_SKB_MAX)
                priv->tx.echo_get = 0;
            if (priv->tx.pending)
                --priv->tx.pending;
            if (card->tx.pending)
                --card->tx.pending;
            ++netdev->stats.tx_packets;
            if (!(msg.can_id & CAN_RTR_FLAG))
                netdev->stats.tx_bytes += msg.can_dlc;
        } else {
            int ret;

            ret = softing_netdev_rx(netdev, &msg, ktime);
            if (ret == NET_RX_SUCCESS) {
                ++netdev->stats.rx_packets;
                if (!(msg.can_id & CAN_RTR_FLAG))
                    netdev->stats.rx_bytes += msg.can_dlc;
            } else {
                ++netdev->stats.rx_dropped;
            }
        }
    }
    ++cnt;
    return cnt;
}

/*
 * real interrupt handler
 */
static irqreturn_t softing_irq_thread(int irq, void *dev_id)
{
    struct softing *card = (struct softing *)dev_id;
    struct net_device *netdev;
    struct softing_priv *priv;
    int j, offset, work_done;

    work_done = 0;
    spin_lock_bh(&card->spin);
    while (softing_handle_1(card) > 0) {
        ++card->irq.svc_count;
        ++work_done;
    }
    spin_unlock_bh(&card->spin);
    /* resume tx queue's */
    offset = card->tx.last_bus;
    for (j = 0; j < ARRAY_SIZE(card->net); ++j) {
        if (card->tx.pending >= TXMAX)
            break;
        netdev = card->net[(j + offset + 1) % card->pdat->nbus];
        if (!netdev)
            continue;
        priv = netdev_priv(netdev);
        if (!canif_is_active(netdev))
            /* it makes no sense to wake dead busses */
            continue;
        if (priv->tx.pending >= TX_ECHO_SKB_MAX)
            continue;
        ++work_done;
        netif_wake_queue(netdev);
    }
    return work_done ? IRQ_HANDLED : IRQ_NONE;
}

/*
 * interrupt routines:
 * schedule the 'real interrupt handler'
 */
static irqreturn_t softing_irq_v2(int irq, void *dev_id)
{
    struct softing *card = (struct softing *)dev_id;
    uint8_t ir;

    ir = ioread8(&card->dpram[DPRAM_V2_IRQ_TOHOST]);
    iowrite8(0, &card->dpram[DPRAM_V2_IRQ_TOHOST]);
    return (1 == ir) ? IRQ_WAKE_THREAD : IRQ_NONE;
}

static irqreturn_t softing_irq_v1(int irq, void *dev_id)
{
    struct softing *card = (struct softing *)dev_id;
    uint8_t ir;

    ir = ioread8(&card->dpram[DPRAM_IRQ_TOHOST]);
    iowrite8(0, &card->dpram[DPRAM_IRQ_TOHOST]);
    return ir ? IRQ_WAKE_THREAD : IRQ_NONE;
}

/*
 * netdev/candev inter-operability
 */
static int softing_netdev_open(struct net_device *ndev)
{
    int ret;

    /* check or determine and set bittime */
    ret = open_candev(ndev);
    if (!ret)
        ret = softing_startstop(ndev, 1);
    return ret;
}

static int softing_netdev_stop(struct net_device *ndev)
{
    int ret;

    netif_stop_queue(ndev);

    /* softing cycle does close_candev() */
    ret = softing_startstop(ndev, 0);
    return ret;
}

static int softing_candev_set_mode(struct net_device *ndev, enum can_mode mode)
{
    int ret;

    switch (mode) {
    case CAN_MODE_START:
        /* softing_startstop does close_candev() */
        ret = softing_startstop(ndev, 1);
        return ret;
    case CAN_MODE_STOP:
    case CAN_MODE_SLEEP:
        return -EOPNOTSUPP;
    }
    return 0;
}

/*
 * Softing device management helpers
 */
int softing_enable_irq(struct softing *card, int enable)
{
    int ret;

    if (!card->irq.nr) {
        return 0;
    } else if (card->irq.requested && !enable) {
        free_irq(card->irq.nr, card);
        card->irq.requested = 0;
    } else if (!card->irq.requested && enable) {
        ret = request_threaded_irq(card->irq.nr,
                (card->pdat->generation >= 2) ?
                    softing_irq_v2 : softing_irq_v1,
                softing_irq_thread, IRQF_SHARED,
                dev_name(&card->pdev->dev), card);
        if (ret) {
            dev_alert(&card->pdev->dev,
                    "request_threaded_irq(%u) failed\n",
                    card->irq.nr);
            return ret;
        }
        card->irq.requested = 1;
    }
    return 0;
}

static void softing_card_shutdown(struct softing *card)
{
    int fw_up = 0;

    if (mutex_lock_interruptible(&card->fw.lock))
        /* return -ERESTARTSYS */;
    fw_up = card->fw.up;
    card->fw.up = 0;

    if (card->irq.requested && card->irq.nr) {
        free_irq(card->irq.nr, card);
        card->irq.requested = 0;
    }
    if (fw_up) {
        if (card->pdat->enable_irq)
            card->pdat->enable_irq(card->pdev, 0);
        softing_set_reset_dpram(card);
        if (card->pdat->reset)
            card->pdat->reset(card->pdev, 1);
    }
    mutex_unlock(&card->fw.lock);
}

static __devinit int softing_card_boot(struct softing *card)
{
    int ret, j;
    static const uint8_t stream[] = {
        0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, };
    unsigned char back[sizeof(stream)];

    if (mutex_lock_interruptible(&card->fw.lock))
        return -ERESTARTSYS;
    if (card->fw.up) {
        mutex_unlock(&card->fw.lock);
        return 0;
    }
    /* reset board */
    if (card->pdat->enable_irq)
        card->pdat->enable_irq(card->pdev, 1);
    /* boot card */
    softing_set_reset_dpram(card);
    if (card->pdat->reset)
        card->pdat->reset(card->pdev, 1);
    for (j = 0; (j + sizeof(stream)) < card->dpram_size;
            j += sizeof(stream)) {

        memcpy_toio(&card->dpram[j], stream, sizeof(stream));
        /* flush IO cache */
        mb();
        memcpy_fromio(back, &card->dpram[j], sizeof(stream));

        if (!memcmp(back, stream, sizeof(stream)))
            continue;
        /* memory is not equal */
        dev_alert(&card->pdev->dev, "dpram failed at 0x%04x\n", j);
        ret = -EIO;
        goto failed;
    }
    wmb();
    /* load boot firmware */
    ret = softing_load_fw(card->pdat->boot.fw, card, card->dpram,
                card->dpram_size,
                card->pdat->boot.offs - card->pdat->boot.addr);
    if (ret < 0)
        goto failed;
    /* load loader firmware */
    ret = softing_load_fw(card->pdat->load.fw, card, card->dpram,
                card->dpram_size,
                card->pdat->load.offs - card->pdat->load.addr);
    if (ret < 0)
        goto failed;

    if (card->pdat->reset)
        card->pdat->reset(card->pdev, 0);
    softing_clr_reset_dpram(card);
    ret = softing_bootloader_command(card, 0, "card boot");
    if (ret < 0)
        goto failed;
    ret = softing_load_app_fw(card->pdat->app.fw, card);
    if (ret < 0)
        goto failed;

    ret = softing_chip_poweron(card);
    if (ret < 0)
        goto failed;

    card->fw.up = 1;
    mutex_unlock(&card->fw.lock);
    return 0;
failed:
    card->fw.up = 0;
    if (card->pdat->enable_irq)
        card->pdat->enable_irq(card->pdev, 0);
    softing_set_reset_dpram(card);
    if (card->pdat->reset)
        card->pdat->reset(card->pdev, 1);
    mutex_unlock(&card->fw.lock);
    return ret;
}

/*
 * netdev sysfs
 */
static ssize_t show_channel(struct device *dev, struct device_attribute *attr,
        char *buf)
{
    struct net_device *ndev = to_net_dev(dev);
    struct softing_priv *priv = netdev2softing(ndev);

    return sprintf(buf, "%i\n", priv->index);
}

static ssize_t show_chip(struct device *dev, struct device_attribute *attr,
        char *buf)
{
    struct net_device *ndev = to_net_dev(dev);
    struct softing_priv *priv = netdev2softing(ndev);

    return sprintf(buf, "%i\n", priv->chip);
}

static ssize_t show_output(struct device *dev, struct device_attribute *attr,
        char *buf)
{
    struct net_device *ndev = to_net_dev(dev);
    struct softing_priv *priv = netdev2softing(ndev);

    return sprintf(buf, "0x%02x\n", priv->output);
}

static ssize_t store_output(struct device *dev, struct device_attribute *attr,
        const char *buf, size_t count)
{
    struct net_device *ndev = to_net_dev(dev);
    struct softing_priv *priv = netdev2softing(ndev);
    struct softing *card = priv->card;
    unsigned long val;
    int ret;

    ret = strict_strtoul(buf, 0, &val);
    if (ret < 0)
        return ret;
    val &= 0xFF;

    ret = mutex_lock_interruptible(&card->fw.lock);
    if (ret)
        return -ERESTARTSYS;
    if (netif_running(ndev)) {
        mutex_unlock(&card->fw.lock);
        return -EBUSY;
    }
    priv->output = val;
    mutex_unlock(&card->fw.lock);
    return count;
}

static const DEVICE_ATTR(channel, S_IRUGO, show_channel, NULL);
static const DEVICE_ATTR(chip, S_IRUGO, show_chip, NULL);
static const DEVICE_ATTR(output, S_IRUGO | S_IWUSR, show_output, store_output);

static const struct attribute *const netdev_sysfs_attrs[] = {
    &dev_attr_channel.attr,
    &dev_attr_chip.attr,
    &dev_attr_output.attr,
    NULL,
};
static const struct attribute_group netdev_sysfs_group = {
    .name = NULL,
    .attrs = (struct attribute **)netdev_sysfs_attrs,
};

static const struct net_device_ops softing_netdev_ops = {
    .ndo_open = softing_netdev_open,
    .ndo_stop = softing_netdev_stop,
    .ndo_start_xmit = softing_netdev_start_xmit,
};

static const struct can_bittiming_const softing_btr_const = {
    .name = "softing",
    .tseg1_min = 1,
    .tseg1_max = 16,
    .tseg2_min = 1,
    .tseg2_max = 8,
    .sjw_max = 4, /* overruled */
    .brp_min = 1,
    .brp_max = 32, /* overruled */
    .brp_inc = 1,
};


static __devinit struct net_device *softing_netdev_create(struct softing *card,
        uint16_t chip_id)
{
    struct net_device *netdev;
    struct softing_priv *priv;

    netdev = alloc_candev(sizeof(*priv), TX_ECHO_SKB_MAX);
    if (!netdev) {
        dev_alert(&card->pdev->dev, "alloc_candev failed\n");
        return NULL;
    }
    priv = netdev_priv(netdev);
    priv->netdev = netdev;
    priv->card = card;
    memcpy(&priv->btr_const, &softing_btr_const, sizeof(priv->btr_const));
    priv->btr_const.brp_max = card->pdat->max_brp;
    priv->btr_const.sjw_max = card->pdat->max_sjw;
    priv->can.bittiming_const = &priv->btr_const;
    priv->can.clock.freq = 8000000;
    priv->chip = chip_id;
    priv->output = softing_default_output(netdev);
    SET_NETDEV_DEV(netdev, &card->pdev->dev);

    netdev->flags |= IFF_ECHO;
    netdev->netdev_ops = &softing_netdev_ops;
    priv->can.do_set_mode = softing_candev_set_mode;
    priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;

    return netdev;
}

static __devinit int softing_netdev_register(struct net_device *netdev)
{
    int ret;

    netdev->sysfs_groups[0] = &netdev_sysfs_group;
    ret = register_candev(netdev);
    if (ret) {
        dev_alert(&netdev->dev, "register failed\n");
        return ret;
    }
    return 0;
}

static void softing_netdev_cleanup(struct net_device *netdev)
{
    unregister_candev(netdev);
    free_candev(netdev);
}

/*
 * sysfs for Platform device
 */
#define DEV_ATTR_RO(name, member) \
static ssize_t show_##name(struct device *dev, \
        struct device_attribute *attr, char *buf) \
{ \
    struct softing *card = platform_get_drvdata(to_platform_device(dev)); \
    return sprintf(buf, "%u\n", card->member); \
} \
static DEVICE_ATTR(name, 0444, show_##name, NULL)

#define DEV_ATTR_RO_STR(name, member) \
static ssize_t show_##name(struct device *dev, \
        struct device_attribute *attr, char *buf) \
{ \
    struct softing *card = platform_get_drvdata(to_platform_device(dev)); \
    return sprintf(buf, "%s\n", card->member); \
} \
static DEVICE_ATTR(name, 0444, show_##name, NULL)

DEV_ATTR_RO(serial, id.serial);
DEV_ATTR_RO_STR(firmware, pdat->app.fw);
DEV_ATTR_RO(firmware_version, id.fw_version);
DEV_ATTR_RO_STR(hardware, pdat->name);
DEV_ATTR_RO(hardware_version, id.hw_version);
DEV_ATTR_RO(license, id.license);
DEV_ATTR_RO(frequency, id.freq);
DEV_ATTR_RO(txpending, tx.pending);

static struct attribute *softing_pdev_attrs[] = {
    &dev_attr_serial.attr,
    &dev_attr_firmware.attr,
    &dev_attr_firmware_version.attr,
    &dev_attr_hardware.attr,
    &dev_attr_hardware_version.attr,
    &dev_attr_license.attr,
    &dev_attr_frequency.attr,
    &dev_attr_txpending.attr,
    NULL,
};

static const struct attribute_group softing_pdev_group = {
    .name = NULL,
    .attrs = softing_pdev_attrs,
};

/*
 * platform driver
 */
static __devexit int softing_pdev_remove(struct platform_device *pdev)
{
    struct softing *card = platform_get_drvdata(pdev);
    int j;

    /* first, disable card*/
    softing_card_shutdown(card);

    for (j = 0; j < ARRAY_SIZE(card->net); ++j) {
        if (!card->net[j])
            continue;
        softing_netdev_cleanup(card->net[j]);
        card->net[j] = NULL;
    }
    sysfs_remove_group(&pdev->dev.kobj, &softing_pdev_group);

    iounmap(card->dpram);
    kfree(card);
    return 0;
}

static __devinit int softing_pdev_probe(struct platform_device *pdev)
{
    const struct softing_platform_data *pdat = pdev->dev.platform_data;
    struct softing *card;
    struct net_device *netdev;
    struct softing_priv *priv;
    struct resource *pres;
    int ret;
    int j;

    if (!pdat) {
        dev_warn(&pdev->dev, "no platform data\n");
        return -EINVAL;
    }
    if (pdat->nbus > ARRAY_SIZE(card->net)) {
        dev_warn(&pdev->dev, "%u nets??\n", pdat->nbus);
        return -EINVAL;
    }

    card = kzalloc(sizeof(*card), GFP_KERNEL);
    if (!card)
        return -ENOMEM;
    card->pdat = pdat;
    card->pdev = pdev;
    platform_set_drvdata(pdev, card);
    mutex_init(&card->fw.lock);
    spin_lock_init(&card->spin);

    ret = -EINVAL;
    pres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!pres)
        goto platform_resource_failed;
    card->dpram_phys = pres->start;
    card->dpram_size = resource_size(pres);
    card->dpram = ioremap_nocache(card->dpram_phys, card->dpram_size);
    if (!card->dpram) {
        dev_alert(&card->pdev->dev, "dpram ioremap failed\n");
        goto ioremap_failed;
    }

    pres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
    if (pres)
        card->irq.nr = pres->start;

    /* reset card */
    ret = softing_card_boot(card);
    if (ret < 0) {
        dev_alert(&pdev->dev, "failed to boot\n");
        goto boot_failed;
    }

    /* only now, the chip's are known */
    card->id.freq = card->pdat->freq;

    ret = sysfs_create_group(&pdev->dev.kobj, &softing_pdev_group);
    if (ret < 0) {
        dev_alert(&card->pdev->dev, "sysfs failed\n");
        goto sysfs_failed;
    }

    for (j = 0; j < ARRAY_SIZE(card->net); ++j) {
        card->net[j] = netdev =
            softing_netdev_create(card, card->id.chip[j]);
        if (!netdev) {
            dev_alert(&pdev->dev, "failed to make can[%i]", j);
            ret = -ENOMEM;
            goto netdev_failed;
        }
        priv = netdev_priv(card->net[j]);
        priv->index = j;
        ret = softing_netdev_register(netdev);
        if (ret) {
            free_candev(netdev);
            card->net[j] = NULL;
            dev_alert(&card->pdev->dev,
                    "failed to register can[%i]\n", j);
            goto netdev_failed;
        }
    }
    dev_info(&card->pdev->dev, "%s ready.\n", card->pdat->name);
    return 0;

netdev_failed:
    for (j = 0; j < ARRAY_SIZE(card->net); ++j) {
        if (!card->net[j])
            continue;
        softing_netdev_cleanup(card->net[j]);
    }
    sysfs_remove_group(&pdev->dev.kobj, &softing_pdev_group);
sysfs_failed:
    softing_card_shutdown(card);
boot_failed:
    iounmap(card->dpram);
ioremap_failed:
platform_resource_failed:
    kfree(card);
    return ret;
}

static struct platform_driver softing_driver = {
    .driver = {
        .name = "softing",
        .owner = THIS_MODULE,
    },
    .probe = softing_pdev_probe,
    .remove = __devexit_p(softing_pdev_remove),
};

module_platform_driver(softing_driver);

MODULE_ALIAS("platform:softing");
MODULE_DESCRIPTION("Softing DPRAM CAN driver");
MODULE_AUTHOR("Kurt Van Dijck <[email protected]>");
MODULE_LICENSE("GPL v2");