From 70ee63ef3d0cf2f754bffc69e3f46b13ea78587f Mon Sep 17 00:00:00 2001
From: Dirk Ziegelmeier <dirk@ziegelmeier.net>
Date: Fri, 5 Aug 2016 09:53:50 +0200
Subject: [PATCH] Documentation: Add example code for NO_SYS use case

---
 doc/NO_SYS_SampleCode.c | 115 ++++++++++++++++++++++++++++++++++++++++
 src/core/init.c         |   4 +-
 2 files changed, 118 insertions(+), 1 deletion(-)
 create mode 100644 doc/NO_SYS_SampleCode.c

diff --git a/doc/NO_SYS_SampleCode.c b/doc/NO_SYS_SampleCode.c
new file mode 100644
index 00000000..a62cc545
--- /dev/null
+++ b/doc/NO_SYS_SampleCode.c
@@ -0,0 +1,115 @@
+void eth_mac_irq()
+{
+  /* Service MAC IRQ here */
+
+  /* Allocate pbuf */
+  struct pbuf* p = pbuf_alloc(PBUF_RAW, eth_data_count, PBUF_RAM);
+
+  if(p != NULL) {
+    /* Copy ethernet frame into pbuf */
+    pbuf_take(p, eth_data, eth_data_count);
+
+    /* Put in a queue which is processed in main loop */
+    if(!queue->tryPut(p)) {
+      /* queue is full -> packet loss */
+      pbuf_free(p);
+    }
+  }
+}
+
+static err_t netif_output(struct netif *netif, struct pbuf *p)
+{
+  LINK_STATS_INC(link.xmit);
+  MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p->tot_len);
+
+  /* Update SNMP stats (only if you use SNMP) */
+  int unicast = ((p->payload[0] & 0x01) == 0);
+  if (unicast) {
+    MIB2_STATS_NETIF_INC(netif, ifoutucastpkts);
+  } else {
+    MIB2_STATS_NETIF_INC(netif, ifoutnucastpkts);
+  }
+
+  LockInterrupts();
+  pbuf_copy_partial(p, mac_send_buffer, p->tot_len, 0);
+  /* Start MAC transmit here */
+  UnlockInterrupts();
+
+  return ERR_OK;
+}
+
+static void netif_status_callback(struct netif *netif)
+{
+  printf("netif status changed %s\n", ip4addr_ntoa(netif_ip4_addr(netif)));
+}
+
+static err_t netif_init(struct netif *netif)
+{
+  netif->linkoutput = netif_output;
+  netif->output = etharp_output;
+  netif->name[0] = 'e';
+  netif->name[1] = '0';
+  netif->mtu = ETHERNET_MTU;
+
+  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_ETHERNET | NETIF_FLAG_IGMP;
+  MIB2_INIT_NETIF(netif, snmp_ifType_ethernet_csmacd, 100000000);
+
+  memcpy(netif->hwaddr, your_mac_address_goes_here, sizeof(netif->hwaddr));
+  netif->hwaddr_len = sizeof(netif->hwaddr);
+
+  return ERR_OK;
+}
+
+void main(void)
+{
+  struct netif netif;
+
+  lwip_init();
+
+  netif_add(&netif, IPADDR_ANY, IPADDR_ANY, IPADDR_ANY, NULL, netif_init, netif_input);
+  netif_set_status_callback(&netif, netif_status_callback);
+  netif_set_default(&netif);
+  netif_set_up(&netif);
+  
+  /* Start DHCP */
+  dhcp_init();
+
+  while(1) {
+    /* Check link state, e.g. via MDIO communication with PHY */
+    if(linkStateChanged()) {
+      if(linkIsUp()) {
+        netif_set_link_up(&netif);
+      } else {
+        netif_set_link_down(&netif);
+      }
+    }
+
+    /* Check for received frames, feed them to lwIP */
+    LockInterrupts();
+    struct pbuf* p = queue->tryGet();
+    UnlockInterrupts();
+
+    if(p != NULL) {
+      LINK_STATS_INC(link.recv);
+  
+      /* Update SNMP stats (only if you use SNMP) */
+      MIB2_STATS_NETIF_ADD(netif, ifinoctets, p->tot_len);
+
+      int unicast = ((p->payload[0] & 0x01) == 0);
+      if (unicast) {
+        MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
+      } else {
+        MIB2_STATS_NETIF_INC(netif, ifinnucastpkts);
+      }
+
+      if(netif.input(p, &netif) != ERR_OK) {
+        pbuf_free(p);
+      }
+    }
+     
+    /* Cyclic lwIP timers check */
+    sys_check_timeouts();
+     
+    /* your application goes here */
+  }
+}
diff --git a/src/core/init.c b/src/core/init.c
index 092cd2bc..bce01bef 100644
--- a/src/core/init.c
+++ b/src/core/init.c
@@ -44,7 +44,9 @@
  * context and put them into a queue which is processed from mainloop.\n
  * Call sys_check_timeouts() periodically in the mainloop.\n
  * Porting: implement all functions in @ref sys_time and @ref sys_prot.\n
- * You can only use @ref callbackstyle_api in this mode.
+ * You can only use @ref callbackstyle_api in this mode.\n
+ * Sample code:\n
+ * @verbinclude NO_SYS_SampleCode.c
  *
  * @defgroup lwip_os OS mode (TCPIP thread)
  * @ingroup lwip