nfeth.c

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/*
 * atari_nfeth.c - ARAnyM ethernet card driver for GNU/Linux
 *
 * Copyright (c) 2005 Milan Jurik, Petr Stehlik of ARAnyM dev team
 *
 * Based on ARAnyM driver for FreeMiNT written by Standa Opichal
 *
 * This software may be used and distributed according to the terms of
 * the GNU General Public License (GPL), incorporated herein by reference.
 */

#define DRV_VERSION "0.3"
#define DRV_RELDATE "10/12/2005"

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <asm/natfeat.h>
#include <asm/virtconvert.h>

enum {
    GET_VERSION = 0,/* no parameters, return NFAPI_VERSION in d0 */
    XIF_INTLEVEL,   /* no parameters, return Interrupt Level in d0 */
    XIF_IRQ,    /* acknowledge interrupt from host */
    XIF_START,  /* (ethX), called on 'ifup', start receiver thread */
    XIF_STOP,   /* (ethX), called on 'ifdown', stop the thread */
    XIF_READLENGTH, /* (ethX), return size of network data block to read */
    XIF_READBLOCK,  /* (ethX, buffer, size), read block of network data */
    XIF_WRITEBLOCK, /* (ethX, buffer, size), write block of network data */
    XIF_GET_MAC,    /* (ethX, buffer, size), return MAC HW addr in buffer */
    XIF_GET_IPHOST, /* (ethX, buffer, size), return IP address of host */
    XIF_GET_IPATARI,/* (ethX, buffer, size), return IP address of atari */
    XIF_GET_NETMASK /* (ethX, buffer, size), return IP netmask */
};

#define MAX_UNIT    8

/* These identify the driver base version and may not be removed. */
static const char version[] __devinitconst =
    KERN_INFO KBUILD_MODNAME ".c:v" DRV_VERSION " " DRV_RELDATE
    " S.Opichal, M.Jurik, P.Stehlik\n"
    KERN_INFO " http://aranym.org/\n";

MODULE_AUTHOR("Milan Jurik");
MODULE_DESCRIPTION("Atari NFeth driver");
MODULE_LICENSE("GPL");
/*
MODULE_PARM(nfeth_debug, "i");
MODULE_PARM_DESC(nfeth_debug, "nfeth_debug level (1-2)");
*/


static long nfEtherID;
static int nfEtherIRQ;

struct nfeth_private {
    int ethX;
};

static struct net_device *nfeth_dev[MAX_UNIT];

static int nfeth_open(struct net_device *dev)
{
    struct nfeth_private *priv = netdev_priv(dev);
    int res;

    res = nf_call(nfEtherID + XIF_START, priv->ethX);
    netdev_dbg(dev, "%s: %d\n", __func__, res);

    /* Ready for data */
    netif_start_queue(dev);

    return 0;
}

static int nfeth_stop(struct net_device *dev)
{
    struct nfeth_private *priv = netdev_priv(dev);

    /* No more data */
    netif_stop_queue(dev);

    nf_call(nfEtherID + XIF_STOP, priv->ethX);

    return 0;
}

/*
 * Read a packet out of the adapter and pass it to the upper layers
 */
static inline void recv_packet(struct net_device *dev)
{
    struct nfeth_private *priv = netdev_priv(dev);
    unsigned short pktlen;
    struct sk_buff *skb;

    /* read packet length (excluding 32 bit crc) */
    pktlen = nf_call(nfEtherID + XIF_READLENGTH, priv->ethX);

    netdev_dbg(dev, "%s: %u\n", __func__, pktlen);

    if (!pktlen) {
        netdev_dbg(dev, "%s: pktlen == 0\n", __func__);
        dev->stats.rx_errors++;
        return;
    }

    skb = dev_alloc_skb(pktlen + 2);
    if (!skb) {
        netdev_dbg(dev, "%s: out of mem (buf_alloc failed)\n",
               __func__);
        dev->stats.rx_dropped++;
        return;
    }

    skb->dev = dev;
    skb_reserve(skb, 2);        /* 16 Byte align  */
    skb_put(skb, pktlen);       /* make room */
    nf_call(nfEtherID + XIF_READBLOCK, priv->ethX, virt_to_phys(skb->data),
        pktlen);

    skb->protocol = eth_type_trans(skb, dev);
    netif_rx(skb);
    dev->last_rx = jiffies;
    dev->stats.rx_packets++;
    dev->stats.rx_bytes += pktlen;

    /* and enqueue packet */
    return;
}

static irqreturn_t nfeth_interrupt(int irq, void *dev_id)
{
    int i, m, mask;

    mask = nf_call(nfEtherID + XIF_IRQ, 0);
    for (i = 0, m = 1; i < MAX_UNIT; m <<= 1, i++) {
        if (mask & m && nfeth_dev[i]) {
            recv_packet(nfeth_dev[i]);
            nf_call(nfEtherID + XIF_IRQ, m);
        }
    }
    return IRQ_HANDLED;
}

static int nfeth_xmit(struct sk_buff *skb, struct net_device *dev)
{
    unsigned int len;
    char *data, shortpkt[ETH_ZLEN];
    struct nfeth_private *priv = netdev_priv(dev);

    data = skb->data;
    len = skb->len;
    if (len < ETH_ZLEN) {
        memset(shortpkt, 0, ETH_ZLEN);
        memcpy(shortpkt, data, len);
        data = shortpkt;
        len = ETH_ZLEN;
    }

    netdev_dbg(dev, "%s: send %u bytes\n", __func__, len);
    nf_call(nfEtherID + XIF_WRITEBLOCK, priv->ethX, virt_to_phys(data),
        len);

    dev->stats.tx_packets++;
    dev->stats.tx_bytes += len;

    dev_kfree_skb(skb);
    return 0;
}

static void nfeth_tx_timeout(struct net_device *dev)
{
    dev->stats.tx_errors++;
    netif_wake_queue(dev);
}

static const struct net_device_ops nfeth_netdev_ops = {
    .ndo_open       = nfeth_open,
    .ndo_stop       = nfeth_stop,
    .ndo_start_xmit     = nfeth_xmit,
    .ndo_tx_timeout     = nfeth_tx_timeout,
    .ndo_validate_addr  = eth_validate_addr,
    .ndo_change_mtu     = eth_change_mtu,
    .ndo_set_mac_address    = eth_mac_addr,
};

static struct net_device * __init nfeth_probe(int unit)
{
    struct net_device *dev;
    struct nfeth_private *priv;
    char mac[ETH_ALEN], host_ip[32], local_ip[32];
    int err;

    if (!nf_call(nfEtherID + XIF_GET_MAC, unit, mac, ETH_ALEN))
        return NULL;

    dev = alloc_etherdev(sizeof(struct nfeth_private));
    if (!dev)
        return NULL;

    dev->irq = nfEtherIRQ;
    dev->netdev_ops = &nfeth_netdev_ops;

    memcpy(dev->dev_addr, mac, ETH_ALEN);

    priv = netdev_priv(dev);
    priv->ethX = unit;

    err = register_netdev(dev);
    if (err) {
        free_netdev(dev);
        return NULL;
    }

    nf_call(nfEtherID + XIF_GET_IPHOST, unit,
        host_ip, sizeof(host_ip));
    nf_call(nfEtherID + XIF_GET_IPATARI, unit,
        local_ip, sizeof(local_ip));

    netdev_info(dev, KBUILD_MODNAME " addr:%s (%s) HWaddr:%pM\n", host_ip,
            local_ip, mac);

    return dev;
}

static int __init nfeth_init(void)
{
    long ver;
    int error, i;

    nfEtherID = nf_get_id("ETHERNET");
    if (!nfEtherID)
        return -ENODEV;

    ver = nf_call(nfEtherID + GET_VERSION);
    pr_info("API %lu\n", ver);

    nfEtherIRQ = nf_call(nfEtherID + XIF_INTLEVEL);
    error = request_irq(nfEtherIRQ, nfeth_interrupt, IRQF_SHARED,
                "eth emu", nfeth_interrupt);
    if (error) {
        pr_err("request for irq %d failed %d", nfEtherIRQ, error);
        return error;
    }

    for (i = 0; i < MAX_UNIT; i++)
        nfeth_dev[i] = nfeth_probe(i);

    return 0;
}

static void __exit nfeth_cleanup(void)
{
    int i;

    for (i = 0; i < MAX_UNIT; i++) {
        if (nfeth_dev[i]) {
            unregister_netdev(nfeth_dev[0]);
            free_netdev(nfeth_dev[0]);
        }
    }
    free_irq(nfEtherIRQ, nfeth_interrupt);
}

module_init(nfeth_init);
module_exit(nfeth_cleanup);