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hysdn_net.c

/* $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 (werner@titro.de) for Hypercope GmbH
 * Copyright 1999 by Werner Cornelius (werner@titro.de)
 *
 * 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 (becker@CESDIS.gsfc.nasa.gov)
 *
 */

#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);

/* store the actual version for log reporting */
char *hysdn_net_revision = "$Revision: 1.8.6.4 $";

#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 {
      struct net_device netdev;     /* the network device */
      struct net_device_stats stats;
      /* additional vars may be added here */
      char dev_name[9]; /* our own device name */

      /* 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.
       */
      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 */


/*****************************************************/
/* Get the current statistics for this card.         */
/* This may be called with the card open or closed ! */
/*****************************************************/
static struct net_device_stats *
net_get_stats(struct net_device *dev)
{
      return (&((struct net_local *) dev)->stats);
}                       /* net_device_stats */

/*********************************************************************/
/* 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->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 - sizeof(unsigned long); 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(unsigned long)), &ifa->ifa_local, sizeof(unsigned long));
            }
      } 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 int
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->priv)->irq_queue);
      }
      return (0);       /* 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->stats.tx_packets++;
      lp->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 sk_buff *skb;

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

      lp->stats.rx_bytes += len;

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

      /* determine the used protocol */
      skb->protocol = eth_type_trans(skb, &lp->netdev);

      netif_rx(skb);
      lp->stats.rx_packets++; /* adjust packet count */

}                       /* 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 */


/*******************************************/
/* init function called by register device */
/*******************************************/
static int
net_init(struct net_device *dev)
{
      /* setup the function table */
      dev->open = net_open;
      dev->stop = net_close;
      dev->hard_start_xmit = net_send_packet;
      dev->get_stats = net_get_stats;

      /* Fill in the fields of the device structure with ethernet values. */
      ether_setup(dev);

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

/*****************************************************************************/
/* 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;
      if(!card) {
            printk(KERN_WARNING "No card-pt in hysdn_net_create!\n");
            return (-ENOMEM);
      }
      hysdn_net_release(card);      /* release an existing net device */
      if ((dev = kzalloc(sizeof(struct net_local), GFP_KERNEL)) == NULL) {
            printk(KERN_WARNING "HYSDN: unable to allocate mem\n");
            return (-ENOMEM);
      }

      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->init = net_init;   /* the init function of the device */
      if(dev->name) {
            strcpy(dev->name, ((struct net_local *) dev)->dev_name);
      } 
      if ((i = register_netdev(dev))) {
            printk(KERN_WARNING "HYSDN: unable to create network device\n");
            kfree(dev);
            return (i);
      }
      dev->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 */
      dev->stop(dev);         /* close the device */

      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 */

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