hysdn_net.c

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/* $Id: hysdn_net.c,v 1.8.6.4 2001/09/23 22:24:54 kai Exp $
 *
 * Linux driver for HYSDN cards, net (ethernet type) handling routines.
 *
 * Author    Werner Cornelius ([email protected]) for Hypercope GmbH
 * Copyright 1999 by Werner Cornelius ([email protected])
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 * This net module has been inspired by the skeleton driver from
 * Donald Becker ([email protected])
 *
 */

#include <linux/module.h>
#include <linux/signal.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/inetdevice.h>

#include "hysdn_defs.h"

unsigned int hynet_enable = 0xffffffff;
module_param(hynet_enable, uint, 0);

#define MAX_SKB_BUFFERS 20  /* number of buffers for keeping TX-data */

/****************************************************************************/
/* structure containing the complete network data. The structure is aligned */
/* in a way that both, the device and statistics are kept inside it.        */
/* for proper access, the device structure MUST be the first var/struct     */
/* inside the definition.                                                   */
/****************************************************************************/
struct net_local {
    /* Tx control lock.  This protects the transmit buffer ring
     * state along with the "tx full" state of the driver.  This
     * means all netif_queue flow control actions are protected
     * by this lock as well.
     */
    struct net_device *dev;
    spinlock_t lock;
    struct sk_buff *skbs[MAX_SKB_BUFFERS];  /* pointers to tx-skbs */
    int in_idx, out_idx;    /* indexes to buffer ring */
    int sk_count;       /* number of buffers currently in ring */
};              /* net_local */



/*********************************************************************/
/* Open/initialize the board. This is called (in the current kernel) */
/* sometime after booting when the 'ifconfig' program is run.        */
/* This routine should set everything up anew at each open, even     */
/* registers that "should" only need to be set once at boot, so that */
/* there is non-reboot way to recover if something goes wrong.       */
/*********************************************************************/
static int
net_open(struct net_device *dev)
{
    struct in_device *in_dev;
    hysdn_card *card = dev->ml_priv;
    int i;

    netif_start_queue(dev); /* start tx-queueing */

    /* Fill in the MAC-level header (if not already set) */
    if (!card->mac_addr[0]) {
        for (i = 0; i < ETH_ALEN; i++)
            dev->dev_addr[i] = 0xfc;
        if ((in_dev = dev->ip_ptr) != NULL) {
            struct in_ifaddr *ifa = in_dev->ifa_list;
            if (ifa != NULL)
                memcpy(dev->dev_addr + (ETH_ALEN - sizeof(ifa->ifa_local)), &ifa->ifa_local, sizeof(ifa->ifa_local));
        }
    } else
        memcpy(dev->dev_addr, card->mac_addr, ETH_ALEN);

    return (0);
}               /* net_open */

/*******************************************/
/* flush the currently occupied tx-buffers */
/* must only be called when device closed  */
/*******************************************/
static void
flush_tx_buffers(struct net_local *nl)
{

    while (nl->sk_count) {
        dev_kfree_skb(nl->skbs[nl->out_idx++]);     /* free skb */
        if (nl->out_idx >= MAX_SKB_BUFFERS)
            nl->out_idx = 0;    /* wrap around */
        nl->sk_count--;
    }
}               /* flush_tx_buffers */


/*********************************************************************/
/* close/decativate the device. The device is not removed, but only  */
/* deactivated.                                                      */
/*********************************************************************/
static int
net_close(struct net_device *dev)
{

    netif_stop_queue(dev);  /* disable queueing */

    flush_tx_buffers((struct net_local *) dev);

    return (0);     /* success */
}               /* net_close */

/************************************/
/* send a packet on this interface. */
/* new style for kernel >= 2.3.33   */
/************************************/
static netdev_tx_t
net_send_packet(struct sk_buff *skb, struct net_device *dev)
{
    struct net_local *lp = (struct net_local *) dev;

    spin_lock_irq(&lp->lock);

    lp->skbs[lp->in_idx++] = skb;   /* add to buffer list */
    if (lp->in_idx >= MAX_SKB_BUFFERS)
        lp->in_idx = 0; /* wrap around */
    lp->sk_count++;     /* adjust counter */
    dev->trans_start = jiffies;

    /* If we just used up the very last entry in the
     * TX ring on this device, tell the queueing
     * layer to send no more.
     */
    if (lp->sk_count >= MAX_SKB_BUFFERS)
        netif_stop_queue(dev);

    /* When the TX completion hw interrupt arrives, this
     * is when the transmit statistics are updated.
     */

    spin_unlock_irq(&lp->lock);

    if (lp->sk_count <= 3) {
        schedule_work(&((hysdn_card *) dev->ml_priv)->irq_queue);
    }
    return NETDEV_TX_OK;    /* success */
}               /* net_send_packet */



/***********************************************************************/
/* acknowlegde a packet send. The network layer will be informed about */
/* completion                                                          */
/***********************************************************************/
void
hysdn_tx_netack(hysdn_card *card)
{
    struct net_local *lp = card->netif;

    if (!lp)
        return;     /* non existing device */


    if (!lp->sk_count)
        return;     /* error condition */

    lp->dev->stats.tx_packets++;
    lp->dev->stats.tx_bytes += lp->skbs[lp->out_idx]->len;

    dev_kfree_skb(lp->skbs[lp->out_idx++]);     /* free skb */
    if (lp->out_idx >= MAX_SKB_BUFFERS)
        lp->out_idx = 0;    /* wrap around */

    if (lp->sk_count-- == MAX_SKB_BUFFERS)  /* dec usage count */
        netif_start_queue((struct net_device *) lp);
}               /* hysdn_tx_netack */

/*****************************************************/
/* we got a packet from the network, go and queue it */
/*****************************************************/
void
hysdn_rx_netpkt(hysdn_card *card, unsigned char *buf, unsigned short len)
{
    struct net_local *lp = card->netif;
    struct net_device *dev;
    struct sk_buff *skb;

    if (!lp)
        return;     /* non existing device */

    dev = lp->dev;
    dev->stats.rx_bytes += len;

    skb = dev_alloc_skb(len);
    if (skb == NULL) {
        printk(KERN_NOTICE "%s: Memory squeeze, dropping packet.\n",
               dev->name);
        dev->stats.rx_dropped++;
        return;
    }
    /* copy the data */
    memcpy(skb_put(skb, len), buf, len);

    /* determine the used protocol */
    skb->protocol = eth_type_trans(skb, dev);

    dev->stats.rx_packets++;    /* adjust packet count */

    netif_rx(skb);
}               /* hysdn_rx_netpkt */

/*****************************************************/
/* return the pointer to a network packet to be send */
/*****************************************************/
struct sk_buff *
hysdn_tx_netget(hysdn_card *card)
{
    struct net_local *lp = card->netif;

    if (!lp)
        return (NULL);  /* non existing device */

    if (!lp->sk_count)
        return (NULL);  /* nothing available */

    return (lp->skbs[lp->out_idx]);     /* next packet to send */
}               /* hysdn_tx_netget */

static const struct net_device_ops hysdn_netdev_ops = {
    .ndo_open       = net_open,
    .ndo_stop       = net_close,
    .ndo_start_xmit     = net_send_packet,
    .ndo_change_mtu     = eth_change_mtu,
    .ndo_set_mac_address    = eth_mac_addr,
    .ndo_validate_addr  = eth_validate_addr,
};


/*****************************************************************************/
/* hysdn_net_create creates a new net device for the given card. If a device */
/* already exists, it will be deleted and created a new one. The return value */
/* 0 announces success, else a negative error code will be returned.         */
/*****************************************************************************/
int
hysdn_net_create(hysdn_card *card)
{
    struct net_device *dev;
    int i;
    struct net_local *lp;

    if (!card) {
        printk(KERN_WARNING "No card-pt in hysdn_net_create!\n");
        return (-ENOMEM);
    }
    hysdn_net_release(card);    /* release an existing net device */

    dev = alloc_etherdev(sizeof(struct net_local));
    if (!dev) {
        printk(KERN_WARNING "HYSDN: unable to allocate mem\n");
        return (-ENOMEM);
    }

    lp = netdev_priv(dev);
    lp->dev = dev;

    dev->netdev_ops = &hysdn_netdev_ops;
    spin_lock_init(&((struct net_local *) dev)->lock);

    /* initialise necessary or informing fields */
    dev->base_addr = card->iobase;  /* IO address */
    dev->irq = card->irq;   /* irq */

    dev->netdev_ops = &hysdn_netdev_ops;
    if ((i = register_netdev(dev))) {
        printk(KERN_WARNING "HYSDN: unable to create network device\n");
        free_netdev(dev);
        return (i);
    }
    dev->ml_priv = card;    /* remember pointer to own data structure */
    card->netif = dev;  /* setup the local pointer */

    if (card->debug_flags & LOG_NET_INIT)
        hysdn_addlog(card, "network device created");
    return (0);     /* and return success */
}               /* hysdn_net_create */

/***************************************************************************/
/* hysdn_net_release deletes the net device for the given card. The return */
/* value 0 announces success, else a negative error code will be returned. */
/***************************************************************************/
int
hysdn_net_release(hysdn_card *card)
{
    struct net_device *dev = card->netif;

    if (!dev)
        return (0); /* non existing */

    card->netif = NULL; /* clear out pointer */
    net_close(dev);

    flush_tx_buffers((struct net_local *) dev); /* empty buffers */

    unregister_netdev(dev); /* release the device */
    free_netdev(dev);   /* release the memory allocated */
    if (card->debug_flags & LOG_NET_INIT)
        hysdn_addlog(card, "network device deleted");

    return (0);     /* always successful */
}               /* hysdn_net_release */

/*****************************************************************************/
/* hysdn_net_getname returns a pointer to the name of the network interface. */
/* if the interface is not existing, a "-" is returned.                      */
/*****************************************************************************/
char *
hysdn_net_getname(hysdn_card *card)
{
    struct net_device *dev = card->netif;

    if (!dev)
        return ("-");   /* non existing */

    return (dev->name);
}               /* hysdn_net_getname */