initial commit of lk (little kernel) project
diff --git a/platform/armemu/net.c b/platform/armemu/net.c
new file mode 100644
index 0000000..e27d321
--- /dev/null
+++ b/platform/armemu/net.c
@@ -0,0 +1,398 @@
+#if WITH_LWIP
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without modification, 
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ * 
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+/*
+ * This file is a skeleton for developing Ethernet network interface
+ * drivers for lwIP. Add code to the low_level functions and do a
+ * search-and-replace for the word "ethernetif" to replace it with
+ * something that better describes your network interface.
+ */
+/*
+ * ARMEMU bits
+ * Copyright (c) 2006 Travis Geiselbrecht
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <malloc.h>
+#include <dev/ethernet.h>
+#include <err.h>
+#include <reg.h>
+#include <string.h>
+#include <platform/interrupts.h>
+#include <platform/armemu/memmap.h>
+
+#include "lwip/opt.h"
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/pbuf.h"
+#include "lwip/sys.h"
+#include <lwip/stats.h>
+
+#include "netif/etharp.h"
+
+/* Define those to better describe your network interface. */
+#define IFNAME0 'e'
+#define IFNAME1 'n'
+
+struct ethernetif {
+  struct eth_addr *ethaddr;
+  /* Add whatever per-interface state that is needed here. */
+};
+
+static const struct eth_addr ethbroadcast = {{0xff,0xff,0xff,0xff,0xff,0xff}};
+
+/* Forward declarations. */
+static void  ethernetif_input(struct netif *netif);
+static err_t ethernetif_output(struct netif *netif, struct pbuf *p,
+             struct ip_addr *ipaddr);
+
+static void
+low_level_init(struct netif *netif)
+{
+  struct ethernetif *ethernetif = netif->state;
+  
+  /* set MAC hardware address length */
+  netif->hwaddr_len = 6;
+
+  /* set MAC hardware address */
+  netif->hwaddr[0] = 0;
+  netif->hwaddr[1] = 0x01;
+  netif->hwaddr[2] = 0x02;
+  netif->hwaddr[3] = 0x03;
+  netif->hwaddr[4] = 0x04;
+  netif->hwaddr[5] = 0x05;
+
+  /* maximum transfer unit */
+  netif->mtu = 1500;
+  
+  /* broadcast capability */
+  netif->flags = NETIF_FLAG_BROADCAST;
+ 
+  /* Do whatever else is needed to initialize interface. */  
+}
+
+/*
+ * low_level_output():
+ *
+ * Should do the actual transmission of the packet. The packet is
+ * contained in the pbuf that is passed to the function. This pbuf
+ * might be chained.
+ *
+ */
+
+static err_t
+low_level_output(struct netif *netif, struct pbuf *p)
+{
+  struct ethernetif *ethernetif = netif->state;
+  struct pbuf *q;
+  int i;
+  int j;
+
+#if ETH_PAD_SIZE
+  pbuf_header(p, -ETH_PAD_SIZE);			/* drop the padding word */
+#endif
+
+  /* XXX maybe just a mutex? */
+  enter_critical_section();
+
+  i = 0;
+  for(q = p; q != NULL; q = q->next) {
+    /* Send the data from the pbuf to the interface, one pbuf at a
+       time. The size of the data in each pbuf is kept in the ->len
+       variable. */
+//	debug_dump_memory_bytes(q->payload, q->len);
+	for (j = 0; j < q->len; j++)
+		*REG8(NET_OUT_BUF + i + j) = ((unsigned char *)q->payload)[j];
+	i += q->len;
+  }
+
+  *REG(NET_SEND_LEN) = i;
+  *REG(NET_SEND) = 1;
+
+  exit_critical_section();
+
+#if ETH_PAD_SIZE
+  pbuf_header(p, ETH_PAD_SIZE);			/* reclaim the padding word */
+#endif
+  
+#if LINK_STATS
+  lwip_stats.link.xmit++;
+#endif /* LINK_STATS */      
+
+  return ERR_OK;
+}
+
+/*
+ * low_level_input():
+ *
+ * Should allocate a pbuf and transfer the bytes of the incoming
+ * packet from the interface into the pbuf.
+ *
+ */
+
+static struct pbuf *
+low_level_input(struct netif *netif)
+{
+  struct ethernetif *ethernetif = netif->state;
+  struct pbuf *p, *q;
+  u16_t len;
+  int i;
+  int head, tail;
+
+  /* get the head and tail pointers from the ethernet interface */
+  head = *REG(NET_HEAD);
+  tail = *REG(NET_TAIL);
+
+  if (tail == head)
+	  return NULL; // false alarm
+
+  /* Obtain the size of the packet and put it into the "len"
+     variable. */
+  len = *REG(NET_IN_BUF_LEN);
+
+#if ETH_PAD_SIZE
+  len += ETH_PAD_SIZE;						/* allow room for Ethernet padding */
+#endif
+
+  /* We allocate a pbuf chain of pbufs from the pool. */
+  p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
+  if (p != NULL) {
+
+#if ETH_PAD_SIZE
+    pbuf_header(p, -ETH_PAD_SIZE);			/* drop the padding word */
+#endif
+
+    /* We iterate over the pbuf chain until we have read the entire
+     * packet into the pbuf. */
+    int pos = 0;
+    for(q = p; q != NULL; q = q->next) {
+      /* Read enough bytes to fill this pbuf in the chain. The
+       * available data in the pbuf is given by the q->len
+       * variable. */
+	  for (i=0; i < q->len; i++) {
+		 ((unsigned char *)q->payload)[i] = *REG8(NET_IN_BUF + pos);
+		 pos++;
+	  }
+    }
+
+#if ETH_PAD_SIZE
+    pbuf_header(p, ETH_PAD_SIZE);			/* reclaim the padding word */
+#endif
+
+#if LINK_STATS
+    lwip_stats.link.recv++;
+#endif /* LINK_STATS */      
+  } else {
+#if LINK_STATS
+    lwip_stats.link.memerr++;
+    lwip_stats.link.drop++;
+#endif /* LINK_STATS */      
+  }
+
+  /* push the tail pointer up by one, giving the buffer back to the hardware */
+  *REG(NET_TAIL) = (tail + 1) % NET_IN_BUF_COUNT;
+
+  return p;  
+}
+
+/*
+ * ethernetif_output():
+ *
+ * This function is called by the TCP/IP stack when an IP packet
+ * should be sent. It calls the function called low_level_output() to
+ * do the actual transmission of the packet.
+ *
+ */
+
+static err_t
+ethernetif_output(struct netif *netif, struct pbuf *p,
+      struct ip_addr *ipaddr)
+{
+//	dprintf("ethernetif_output: netif %p, pbuf %p, ipaddr %p\n", netif, p, ipaddr);
+  
+ /* resolve hardware address, then send (or queue) packet */
+  return etharp_output(netif, ipaddr, p);
+ 
+}
+
+/*
+ * ethernetif_input():
+ *
+ * This function should be called when a packet is ready to be read
+ * from the interface. It uses the function low_level_input() that
+ * should handle the actual reception of bytes from the network
+ * interface.
+ *
+ */
+
+static void
+ethernetif_input(struct netif *netif)
+{
+  struct ethernetif *ethernetif;
+  struct eth_hdr *ethhdr;
+  struct pbuf *p;
+
+  ethernetif = netif->state;
+  
+  /* move received packet into a new pbuf */
+  p = low_level_input(netif);
+  /* no packet could be read, silently ignore this */
+  if (p == NULL) return;
+  /* points to packet payload, which starts with an Ethernet header */
+  ethhdr = p->payload;
+
+#if LINK_STATS
+  lwip_stats.link.recv++;
+#endif /* LINK_STATS */
+
+  ethhdr = p->payload;
+
+//  dprintf("ethernetif_input: type 0x%x\n", htons(ethhdr->type));
+    
+  switch (htons(ethhdr->type)) {
+  /* IP packet? */
+  case ETHTYPE_IP:
+    /* update ARP table */
+    etharp_ip_input(netif, p);
+    /* skip Ethernet header */
+    pbuf_header(p, -sizeof(struct eth_hdr));
+    /* pass to network layer */
+    netif->input(p, netif);
+    break;
+      
+    case ETHTYPE_ARP:
+      /* pass p to ARP module  */
+      etharp_arp_input(netif, ethernetif->ethaddr, p);
+      break;
+    default:
+      pbuf_free(p);
+      p = NULL;
+      break;
+  }
+}
+
+static enum handler_return ethernet_int(void *arg)
+{
+	struct netif *netif = (struct netif *)arg;
+
+	ethernetif_input(netif);
+
+	return INT_RESCHEDULE;
+}
+
+
+
+/*
+ * ethernetif_init():
+ *
+ * Should be called at the beginning of the program to set up the
+ * network interface. It calls the function low_level_init() to do the
+ * actual setup of the hardware.
+ *
+ */
+
+static err_t
+ethernetif_init(struct netif *netif)
+{
+  struct ethernetif *ethernetif;
+    
+  ethernetif = mem_malloc(sizeof(struct ethernetif));
+  
+  if (ethernetif == NULL)
+  {
+  	LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_init: out of memory\n"));
+  	return ERR_MEM;
+  }
+  
+  netif->state = ethernetif;
+  netif->name[0] = IFNAME0;
+  netif->name[1] = IFNAME1;
+  netif->output = ethernetif_output;
+  netif->linkoutput = low_level_output;
+  
+  ethernetif->ethaddr = (struct eth_addr *)&(netif->hwaddr[0]);
+  
+  low_level_init(netif);
+
+  return ERR_OK;
+}
+
+status_t ethernet_init(void)
+{
+	/* check to see if the ethernet feature is turned on */
+	if ((*REG(SYSINFO_FEATURES) & SYSINFO_FEATURE_NETWORK) == 0)
+		return ERR_NOT_FOUND;
+
+	struct netif *netif = calloc(sizeof(struct netif), 1);
+	struct ip_addr *ipaddr = calloc(sizeof(struct ip_addr), 1);
+	struct ip_addr *netmask = calloc(sizeof(struct ip_addr), 1);
+	struct ip_addr *gw = calloc(sizeof(struct ip_addr), 1);
+
+	struct netif *netifret = netif_add(netif, ipaddr, netmask, gw, NULL, &ethernetif_init, &ip_input);
+	if (netifret == NULL) {
+		free(netif);
+		free(ipaddr);
+		free(netmask);
+		free(gw);
+		return ERR_NOT_FOUND;
+	}
+
+	/* register for interrupt handlers */
+	register_int_handler(INT_NET, ethernet_int, netif);
+
+	netif_set_default(netif);
+
+	unmask_interrupt(INT_NET, NULL);
+
+	return NO_ERROR;
+}
+
+#endif // WITH_LWIP