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network.c

/*
 *
 * arch/xtensa/platform-iss/network.c
 *
 * Platform specific initialization.
 *
 * Authors: Chris Zankel <chris@zankel.net>
 * Based on work form the UML team.
 *
 * Copyright 2005 Tensilica Inc.
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 */

#include <linux/list.h>
#include <linux/irq.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/if_ether.h>
#include <linux/inetdevice.h>
#include <linux/init.h>
#include <linux/if_tun.h>
#include <linux/etherdevice.h>
#include <linux/interrupt.h>
#include <linux/ioctl.h>
#include <linux/bootmem.h>
#include <linux/ethtool.h>
#include <linux/rtnetlink.h>
#include <linux/timer.h>
#include <linux/platform_device.h>

#include <asm/platform/simcall.h>

#define DRIVER_NAME "iss-netdev"
#define ETH_MAX_PACKET 1500
#define ETH_HEADER_OTHER 14
#define ISS_NET_TIMER_VALUE (2 * HZ)


static DEFINE_SPINLOCK(opened_lock);
static LIST_HEAD(opened);

static DEFINE_SPINLOCK(devices_lock);
static LIST_HEAD(devices);

/* ------------------------------------------------------------------------- */

/* We currently only support the TUNTAP transport protocol. */

#define TRANSPORT_TUNTAP_NAME "tuntap"
#define TRANSPORT_TUNTAP_MTU ETH_MAX_PACKET

struct tuntap_info {
      char dev_name[IFNAMSIZ];
      int fixed_config;
      unsigned char gw[ETH_ALEN];
      int fd;
};

/* ------------------------------------------------------------------------- */


/* This structure contains out private information for the driver. */

struct iss_net_private {

      struct list_head device_list;
      struct list_head opened_list;

      spinlock_t lock;
      struct net_device *dev;
      struct platform_device pdev;
      struct timer_list tl;
      struct net_device_stats stats;

      struct timer_list timer;
      unsigned int timer_val;

      int index;
      int mtu;

      unsigned char mac[ETH_ALEN];
      int have_mac;

      struct {
            union {
                  struct tuntap_info tuntap;
            } info;

            int (*open)(struct iss_net_private *lp);
            void (*close)(struct iss_net_private *lp);
            int (*read)(struct iss_net_private *lp, struct sk_buff **skb);
            int (*write)(struct iss_net_private *lp, struct sk_buff **skb);
            unsigned short (*protocol)(struct sk_buff *skb);
            int (*poll)(struct iss_net_private *lp);
      } tp;

};

/* ======================= ISS SIMCALL INTERFACE =========================== */

/* Note: __simc must _not_ be declared inline! */

static int errno;

static int __simc (int a, int b, int c, int d, int e, int f)
{
      int ret;
      __asm__ __volatile__ ("simcall\n"
                        "mov %0, a2\n"
                        "mov %1, a3\n" : "=a" (ret), "=a" (errno)
                        : : "a2", "a3");
      return ret;
}

static int inline simc_open(char *file, int flags, int mode)
{
      return __simc(SYS_open, (int) file, flags, mode, 0, 0);
}

static int inline simc_close(int fd)
{
      return __simc(SYS_close, fd, 0, 0, 0, 0);
}

static int inline simc_ioctl(int fd, int request, void *arg)
{
      return __simc(SYS_ioctl, fd, request, (int) arg, 0, 0);
}

static int inline simc_read(int fd, void *buf, size_t count)
{
      return __simc(SYS_read, fd, (int) buf, count, 0, 0);
}

static int inline simc_write(int fd, void *buf, size_t count)
{
      return __simc(SYS_write, fd, (int) buf, count, 0, 0);
}

static int inline simc_poll(int fd)
{
      struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };

      return __simc(SYS_select_one, fd, XTISS_SELECT_ONE_READ, (int)&tv,0,0);
}

/* ================================ HELPERS ================================ */


static char *split_if_spec(char *str, ...)
{
      char **arg, *end;
      va_list ap;

      va_start(ap, str);
      while ((arg = va_arg(ap, char**)) != NULL) {
            if (*str == '\0')
                  return NULL;
            end = strchr(str, ',');
            if (end != str)
                  *arg = str;
            if (end == NULL)
                  return NULL;
            *end ++ = '\0';
            str = end;
      }
      va_end(ap);
      return str;
}


#if 0
/* Adjust SKB. */

struct sk_buff *ether_adjust_skb(struct sk_buff *skb, int extra)
{
      if ((skb != NULL) && (skb_tailroom(skb) < extra)) {
            struct sk_buff *skb2;

            skb2 = skb_copy_expand(skb, 0, extra, GFP_ATOMIC);
            dev_kfree_skb(skb);
            skb = skb2;
      }
      if (skb != NULL)
            skb_put(skb, extra);

      return skb;
}
#endif

/* Return the IP address as a string for a given device. */

static void dev_ip_addr(void *d, char *buf, char *bin_buf)
{
      struct net_device *dev = d;
      struct in_device *ip = dev->ip_ptr;
      struct in_ifaddr *in;
      __be32 addr;

      if ((ip == NULL) || ((in = ip->ifa_list) == NULL)) {
            printk(KERN_WARNING "Device not assigned an IP address!\n");
            return;
      }

      addr = in->ifa_address;
      sprintf(buf, "%d.%d.%d.%d", addr & 0xff, (addr >> 8) & 0xff,
            (addr >> 16) & 0xff, addr >> 24);

      if (bin_buf) {
            bin_buf[0] = addr & 0xff;
            bin_buf[1] = (addr >> 8) & 0xff;
            bin_buf[2] = (addr >> 16) & 0xff;
            bin_buf[3] = addr >> 24;
      }
}

/* Set Ethernet address of the specified device. */

static void inline set_ether_mac(void *d, unsigned char *addr)
{
      struct net_device *dev = d;
      memcpy(dev->dev_addr, addr, ETH_ALEN);
}


/* ======================= TUNTAP TRANSPORT INTERFACE ====================== */

static int tuntap_open(struct iss_net_private *lp)
{
      struct ifreq ifr;
      char *dev_name = lp->tp.info.tuntap.dev_name;
      int err = -EINVAL;
      int fd;

      /* We currently only support a fixed configuration. */

      if (!lp->tp.info.tuntap.fixed_config)
            return -EINVAL;

      if ((fd = simc_open("/dev/net/tun", 02, 0)) < 0) {    /* O_RDWR */
            printk("Failed to open /dev/net/tun, returned %d "
                   "(errno = %d)\n", fd, errno);
            return fd;
      }

      memset(&ifr, 0, sizeof ifr);
      ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
      strlcpy(ifr.ifr_name, dev_name, sizeof ifr.ifr_name);

      if ((err = simc_ioctl(fd, TUNSETIFF, (void*) &ifr)) < 0) {
            printk("Failed to set interface, returned %d "
                   "(errno = %d)\n", err, errno);
            simc_close(fd);
            return err;
      }

      lp->tp.info.tuntap.fd = fd;
      return err;
}

static void tuntap_close(struct iss_net_private *lp)
{
#if 0
      if (lp->tp.info.tuntap.fixed_config)
            iter_addresses(lp->tp.info.tuntap.dev, close_addr, lp->host.dev_name);
#endif
      simc_close(lp->tp.info.tuntap.fd);
      lp->tp.info.tuntap.fd = -1;
}

static int tuntap_read (struct iss_net_private *lp, struct sk_buff **skb)
{
#if 0
      *skb = ether_adjust_skb(*skb, ETH_HEADER_OTHER);
      if (*skb == NULL)
            return -ENOMEM;
#endif

      return simc_read(lp->tp.info.tuntap.fd,
                  (*skb)->data, (*skb)->dev->mtu + ETH_HEADER_OTHER);
}

static int tuntap_write (struct iss_net_private *lp, struct sk_buff **skb)
{
      return simc_write(lp->tp.info.tuntap.fd, (*skb)->data, (*skb)->len);
}

unsigned short tuntap_protocol(struct sk_buff *skb)
{
      return eth_type_trans(skb, skb->dev);
}

static int tuntap_poll(struct iss_net_private *lp)
{
      return simc_poll(lp->tp.info.tuntap.fd);
}

/*
 * Currently only a device name is supported.
 * ethX=tuntap[,[mac address][,[device name]]]
 */

static int tuntap_probe(struct iss_net_private *lp, int index, char *init)
{
      const int len = strlen(TRANSPORT_TUNTAP_NAME);
      char *dev_name = NULL, *mac_str = NULL, *rem = NULL;

      /* Transport should be 'tuntap': ethX=tuntap,mac,dev_name */

      if (strncmp(init, TRANSPORT_TUNTAP_NAME, len))
            return 0;

      if (*(init += strlen(TRANSPORT_TUNTAP_NAME)) == ',') {
            if ((rem=split_if_spec(init+1, &mac_str, &dev_name)) != NULL) {
                  printk("Extra garbage on specification : '%s'\n", rem);
                  return 0;
            }
      } else if (*init != '\0') {
            printk("Invalid argument: %s. Skipping device!\n", init);
            return 0;
      }

      if (dev_name) {
            strncpy(lp->tp.info.tuntap.dev_name, dev_name,
                   sizeof lp->tp.info.tuntap.dev_name);
            lp->tp.info.tuntap.fixed_config = 1;
      } else
            strcpy(lp->tp.info.tuntap.dev_name, TRANSPORT_TUNTAP_NAME);


#if 0
      if (setup_etheraddr(mac_str, lp->mac))
            lp->have_mac = 1;
#endif
      lp->mtu = TRANSPORT_TUNTAP_MTU;

      //lp->info.tuntap.gate_addr = gate_addr;

      lp->tp.info.tuntap.fd = -1;

      lp->tp.open = tuntap_open;
      lp->tp.close = tuntap_close;
      lp->tp.read = tuntap_read;
      lp->tp.write = tuntap_write;
      lp->tp.protocol = tuntap_protocol;
      lp->tp.poll = tuntap_poll;

      printk("TUN/TAP backend - ");
#if 0
      if (lp->host.gate_addr != NULL)
            printk("IP = %s", lp->host.gate_addr);
#endif
      printk("\n");

      return 1;
}

/* ================================ ISS NET ================================ */

static int iss_net_rx(struct net_device *dev)
{
      struct iss_net_private *lp = dev->priv;
      int pkt_len;
      struct sk_buff *skb;

      /* Check if there is any new data. */

      if (lp->tp.poll(lp) == 0)
            return 0;

      /* Try to allocate memory, if it fails, try again next round. */

      if ((skb = dev_alloc_skb(dev->mtu + 2 + ETH_HEADER_OTHER)) == NULL) {
            lp->stats.rx_dropped++;
            return 0;
      }

      skb_reserve(skb, 2);

      /* Setup skb */

      skb->dev = dev;
      skb_reset_mac_header(skb);
      pkt_len = lp->tp.read(lp, &skb);
      skb_put(skb, pkt_len);

      if (pkt_len > 0) {
            skb_trim(skb, pkt_len);
            skb->protocol = lp->tp.protocol(skb);

            lp->stats.rx_bytes += skb->len;
            lp->stats.rx_packets++;
      //    netif_rx(skb);
            netif_rx_ni(skb);
            return pkt_len;
      }
      kfree_skb(skb);
      return pkt_len;
}

static int iss_net_poll(void)
{
      struct list_head *ele;
      int err, ret = 0;

      spin_lock(&opened_lock);

      list_for_each(ele, &opened) {
            struct iss_net_private *lp;

            lp = list_entry(ele, struct iss_net_private, opened_list);

            if (!netif_running(lp->dev))
                  break;

            spin_lock(&lp->lock);

            while ((err = iss_net_rx(lp->dev)) > 0)
                  ret++;

            spin_unlock(&lp->lock);

            if (err < 0) {
                  printk(KERN_ERR "Device '%s' read returned %d, "
                         "shutting it down\n", lp->dev->name, err);
                  dev_close(lp->dev);
            } else {
                  // FIXME reactivate_fd(lp->fd, ISS_ETH_IRQ);
            }
      }

      spin_unlock(&opened_lock);
      return ret;
}


static void iss_net_timer(unsigned long priv)
{
      struct iss_net_private* lp = (struct iss_net_private*) priv;

      spin_lock(&lp->lock);

      iss_net_poll();

      mod_timer(&lp->timer, jiffies + lp->timer_val);

      spin_unlock(&lp->lock);
}


static int iss_net_open(struct net_device *dev)
{
      struct iss_net_private *lp = dev->priv;
      char addr[sizeof "255.255.255.255\0"];
      int err;

      spin_lock(&lp->lock);

      if ((err = lp->tp.open(lp)) < 0)
            goto out;

      if (!lp->have_mac) {
            dev_ip_addr(dev, addr, &lp->mac[2]);
            set_ether_mac(dev, lp->mac);
      }

      netif_start_queue(dev);

      /* clear buffer - it can happen that the host side of the interface
       * is full when we get here. In this case, new data is never queued,
       * SIGIOs never arrive, and the net never works.
       */
      while ((err = iss_net_rx(dev)) > 0)
            ;

      spin_lock(&opened_lock);
      list_add(&lp->opened_list, &opened);
      spin_unlock(&opened_lock);

      init_timer(&lp->timer);
      lp->timer_val = ISS_NET_TIMER_VALUE;
      lp->timer.data = (unsigned long) lp;
      lp->timer.function = iss_net_timer;
      mod_timer(&lp->timer, jiffies + lp->timer_val);

out:
      spin_unlock(&lp->lock);
      return err;
}

static int iss_net_close(struct net_device *dev)
{
      struct iss_net_private *lp = dev->priv;
printk("iss_net_close!\n");
      netif_stop_queue(dev);
      spin_lock(&lp->lock);

      spin_lock(&opened_lock);
      list_del(&opened);
      spin_unlock(&opened_lock);

      del_timer_sync(&lp->timer);

      lp->tp.close(lp);

      spin_unlock(&lp->lock);
      return 0;
}

static int iss_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
      struct iss_net_private *lp = dev->priv;
      unsigned long flags;
      int len;

      netif_stop_queue(dev);
      spin_lock_irqsave(&lp->lock, flags);

      len = lp->tp.write(lp, &skb);

      if (len == skb->len) {
            lp->stats.tx_packets++;
            lp->stats.tx_bytes += skb->len;
            dev->trans_start = jiffies;
            netif_start_queue(dev);

            /* this is normally done in the interrupt when tx finishes */
            netif_wake_queue(dev);

      } else if (len == 0) {
            netif_start_queue(dev);
            lp->stats.tx_dropped++;

      } else {
            netif_start_queue(dev);
            printk(KERN_ERR "iss_net_start_xmit: failed(%d)\n", len);
      }

      spin_unlock_irqrestore(&lp->lock, flags);

      dev_kfree_skb(skb);
      return 0;
}


static struct net_device_stats *iss_net_get_stats(struct net_device *dev)
{
      struct iss_net_private *lp = dev->priv;
      return &lp->stats;
}

static void iss_net_set_multicast_list(struct net_device *dev)
{
#if 0
      if (dev->flags & IFF_PROMISC)
            return;
      else if (dev->mc_count)
            dev->flags |= IFF_ALLMULTI;
      else
            dev->flags &= ~IFF_ALLMULTI;
#endif
}

static void iss_net_tx_timeout(struct net_device *dev)
{
#if 0
      dev->trans_start = jiffies;
      netif_wake_queue(dev);
#endif
}

static int iss_net_set_mac(struct net_device *dev, void *addr)
{
#if 0
      struct iss_net_private *lp = dev->priv;
      struct sockaddr *hwaddr = addr;

      spin_lock(&lp->lock);
      memcpy(dev->dev_addr, hwaddr->sa_data, ETH_ALEN);
      spin_unlock(&lp->lock);
#endif

      return 0;
}

static int iss_net_change_mtu(struct net_device *dev, int new_mtu)
{
#if 0
      struct iss_net_private *lp = dev->priv;
      int err = 0;

      spin_lock(&lp->lock);

      // FIXME not needed new_mtu = transport_set_mtu(new_mtu, &lp->user);

      if (new_mtu < 0)
            err = new_mtu;
      else
            dev->mtu = new_mtu;

      spin_unlock(&lp->lock);
      return err;
#endif
      return -EINVAL;
}

void iss_net_user_timer_expire(unsigned long _conn)
{
}


static struct platform_driver iss_net_driver = {
      .driver = {
            .name  = DRIVER_NAME,
      },
};

static int driver_registered;

static int iss_net_configure(int index, char *init)
{
      struct net_device *dev;
      struct iss_net_private *lp;
      int err;

      if ((dev = alloc_etherdev(sizeof *lp)) == NULL) {
            printk(KERN_ERR "eth_configure: failed to allocate device\n");
            return 1;
      }

      /* Initialize private element. */

      lp = dev->priv;
      *lp = ((struct iss_net_private) {
            .device_list            = LIST_HEAD_INIT(lp->device_list),
            .opened_list            = LIST_HEAD_INIT(lp->opened_list),
            .lock             = SPIN_LOCK_UNLOCKED,
            .dev              = dev,
            .index                  = index,
            //.fd                   = -1,
            .mac              = { 0xfe, 0xfd, 0x0, 0x0, 0x0, 0x0 },
            .have_mac         = 0,
            });

      /*
       * Try all transport protocols.
       * Note: more protocols can be added by adding '&& !X_init(lp, eth)'.
       */

      if (!tuntap_probe(lp, index, init)) {
            printk("Invalid arguments. Skipping device!\n");
            goto errout;
      }

      printk(KERN_INFO "Netdevice %d ", index);
      if (lp->have_mac)
            printk("(%02x:%02x:%02x:%02x:%02x:%02x) ",
                        lp->mac[0], lp->mac[1],
                        lp->mac[2], lp->mac[3],
                        lp->mac[4], lp->mac[5]);
      printk(": ");

      /* sysfs register */

      if (!driver_registered) {
            platform_driver_register(&iss_net_driver);
            driver_registered = 1;
      }

      spin_lock(&devices_lock);
      list_add(&lp->device_list, &devices);
      spin_unlock(&devices_lock);

      lp->pdev.id = index;
      lp->pdev.name = DRIVER_NAME;
      platform_device_register(&lp->pdev);
      SET_NETDEV_DEV(dev,&lp->pdev.dev);

      /*
       * If this name ends up conflicting with an existing registered
       * netdevice, that is OK, register_netdev{,ice}() will notice this
       * and fail.
       */
      snprintf(dev->name, sizeof dev->name, "eth%d", index);

      dev->mtu = lp->mtu;
      dev->open = iss_net_open;
      dev->hard_start_xmit = iss_net_start_xmit;
      dev->stop = iss_net_close;
      dev->get_stats = iss_net_get_stats;
      dev->set_multicast_list = iss_net_set_multicast_list;
      dev->tx_timeout = iss_net_tx_timeout;
      dev->set_mac_address = iss_net_set_mac;
      dev->change_mtu = iss_net_change_mtu;
      dev->watchdog_timeo = (HZ >> 1);
      dev->irq = -1;

      rtnl_lock();
      err = register_netdevice(dev);
      rtnl_unlock();

      if (err) {
            printk("Error registering net device!\n");
            /* XXX: should we call ->remove() here? */
            free_netdev(dev);
            return 1;
      }

      init_timer(&lp->tl);
      lp->tl.function = iss_net_user_timer_expire;

#if 0
      if (lp->have_mac)
            set_ether_mac(dev, lp->mac);
#endif
      return 0;

errout:
      // FIXME: unregister; free, etc..
      return -EIO;

}

/* ------------------------------------------------------------------------- */

/* Filled in during early boot */

struct list_head eth_cmd_line = LIST_HEAD_INIT(eth_cmd_line);

struct iss_net_init {
      struct list_head list;
      char *init;       /* init string */
      int index;
};

/*
 * Parse the command line and look for 'ethX=...' fields, and register all
 * those fields. They will be later initialized in iss_net_init.
 */

#define ERR KERN_ERR "iss_net_setup: "

static int iss_net_setup(char *str)
{
      struct iss_net_private *device = NULL;
      struct iss_net_init *new;
      struct list_head *ele;
      char *end;
      int n;

      n = simple_strtoul(str, &end, 0);
      if (end == str) {
            printk(ERR "Failed to parse '%s'\n", str);
            return 1;
      }
      if (n < 0) {
            printk(ERR "Device %d is negative\n", n);
            return 1;
      }
      if (*(str = end) != '=') {
            printk(ERR "Expected '=' after device number\n");
            return 1;
      }

      spin_lock(&devices_lock);

      list_for_each(ele, &devices) {
            device = list_entry(ele, struct iss_net_private, device_list);
            if (device->index == n)
                  break;
      }

      spin_unlock(&devices_lock);

      if (device && device->index == n) {
            printk(ERR "Device %d already configured\n", n);
            return 1;
      }

      if ((new = alloc_bootmem(sizeof new)) == NULL) {
            printk("Alloc_bootmem failed\n");
            return 1;
      }

      INIT_LIST_HEAD(&new->list);
      new->index = n;
      new->init = str + 1;

      list_add_tail(&new->list, &eth_cmd_line);
      return 1;
}

#undef ERR

__setup("eth=", iss_net_setup);

/*
 * Initialize all ISS Ethernet devices previously registered in iss_net_setup.
 */

static int iss_net_init(void)
{
      struct list_head *ele, *next;

      /* Walk through all Ethernet devices specified in the command line. */

      list_for_each_safe(ele, next, &eth_cmd_line) {
            struct iss_net_init *eth;
            eth = list_entry(ele, struct iss_net_init, list);
            iss_net_configure(eth->index, eth->init);
      }

      return 1;
}

module_init(iss_net_init);


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