transparent polling

This is *dependant* on this esp8266 arduino core pull request:
	esp8266/Arduino#6039

Fix #3 (comment)

Author: d-a-v

w5500-lwIP.cpp

@@ -9,6 +9,7 @@
 #include <lwip/dhcp.h>
 
 #include <IPAddress.h>
+#include <FunctionalInterrupt.h>
 
 #ifdef ESP8266
 #include <user_interface.h>	// wifi_get_macaddr()
@@ -21,15 +22,15 @@ boolean Wiznet5500lwIP::begin (SPIparam(SPIClass& spi,) const uint8_t* macAddres
     uint8_t zeros[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
     if (!macAddress)
         macAddress = zeros;
-        
+
     if (!Wiznet5500::begin(SPIparam(spi,) macAddress))
         return false;
     _mtu = mtu;
 
     switch (start_with_dhclient())
     {
     case ERR_OK:
-        return true;
+        break;
 
     case ERR_IF:
         return false;
@@ -38,19 +39,36 @@ boolean Wiznet5500lwIP::begin (SPIparam(SPIClass& spi,) const uint8_t* macAddres
         netif_remove(&_netif);
         return false;
     }
+
+    if (_intrPin >= 0)
+    {
+        ::printf((PGM_P)F("w500-lwIP: Interrupt not implemented yet, enabling transparent polling\r\n"));
+        // still need to enable interrupt in wiznet driver
+        _intrPin = -1;
+    }
+
+    if (_intrPin >= 0)
+        attachInterrupt(_intrPin, [&]() { this->handlePackets(); }, FALLING);
+    else if (!schedule_function_us([&]() { this->handlePackets(); return true; }, 100))
+    {
+        netif_remove(&_netif);
+        return false;
+    }
+
+    return true;
 }
 
 err_t Wiznet5500lwIP::start_with_dhclient ()
 {
     ip4_addr_t ip, mask, gw;
-    
+
     ip4_addr_set_zero(&ip);
     ip4_addr_set_zero(&mask);
     ip4_addr_set_zero(&gw);
-    
+
     _netif.hwaddr_len = sizeof _mac_address;
     memcpy(_netif.hwaddr, _mac_address, sizeof _mac_address);
-    
+
     if (!netif_add(&_netif, &ip, &mask, &gw, this, netif_init_s, ethernet_input))
         return ERR_IF;
 
@@ -62,7 +80,7 @@ err_t Wiznet5500lwIP::start_with_dhclient ()
 err_t Wiznet5500lwIP::linkoutput_s (netif *netif, struct pbuf *pbuf)
 {
     Wiznet5500lwIP* ths = (Wiznet5500lwIP*)netif->state;
-    
+
 #ifdef ESP8266
     if (pbuf->len != pbuf->tot_len || pbuf->next)
         Serial.println("ERRTOT\r\n");
@@ -74,7 +92,7 @@ err_t Wiznet5500lwIP::linkoutput_s (netif *netif, struct pbuf *pbuf)
     if (phy_capture)
         phy_capture(ths->_netif.num, (const char*)pbuf->payload, pbuf->len, /*out*/1, /*success*/len == pbuf->len);
 #endif
-    
+
     return len == pbuf->len? ERR_OK: ERR_MEM;
 }
 
@@ -116,21 +134,21 @@ err_t Wiznet5500lwIP::netif_init ()
     _netif.name[1] = '0' + _netif.num;
     _netif.mtu = _mtu;
     _netif.chksum_flags = NETIF_CHECKSUM_ENABLE_ALL;
-    _netif.flags = 
+    _netif.flags =
           NETIF_FLAG_ETHARP
         | NETIF_FLAG_IGMP
-        | NETIF_FLAG_BROADCAST 
+        | NETIF_FLAG_BROADCAST
         | NETIF_FLAG_LINK_UP;
 
     // lwIP's doc: This function typically first resolves the hardware
     // address, then sends the packet.  For ethernet physical layer, this is
     // usually lwIP's etharp_output()
     _netif.output = etharp_output;
-    
+
     // lwIP's doc: This function outputs the pbuf as-is on the link medium
     // (this must points to the raw ethernet driver, meaning: us)
     _netif.linkoutput = linkoutput_s;
-    
+
     _netif.status_callback = netif_status_callback_s;
 
     return ERR_OK;
@@ -144,55 +162,62 @@ void Wiznet5500lwIP::netif_status_callback ()
         netif_set_default(nullptr);
 }
 
-err_t Wiznet5500lwIP::loop ()
+err_t Wiznet5500lwIP::handlePackets ()
 {
-    uint16_t tot_len = readFrameSize();
-    if (!tot_len)
-        return ERR_OK;
-    
-    // from doc: use PBUF_RAM for TX, PBUF_POOL from RX
-    // however:
-    // PBUF_POOL can return chained pbuf (not in one piece)
-    // and WiznetDriver does not have the proper API to deal with that
-    // so in the meantime, we use PBUF_RAM instead which is currently
-    // guarantying to deliver a continuous chunk of memory.
-    // TODO: tweak the wiznet driver to allow copying partial chunk
-    //       of received data and use PBUF_POOL.
-    pbuf* pbuf = pbuf_alloc(PBUF_RAW, tot_len, PBUF_RAM);
-    if (!pbuf || pbuf->len < tot_len)
+    int pkt = 0;
+    while(1)
     {
-        if (pbuf)
+        if (++pkt == 10)
+            // prevent starvation
+            return ERR_OK;
+
+        uint16_t tot_len = readFrameSize();
+        if (!tot_len)
+            return ERR_OK;
+
+        // from doc: use PBUF_RAM for TX, PBUF_POOL from RX
+        // however:
+        // PBUF_POOL can return chained pbuf (not in one piece)
+        // and WiznetDriver does not have the proper API to deal with that
+        // so in the meantime, we use PBUF_RAM instead which is currently
+        // guarantying to deliver a continuous chunk of memory.
+        // TODO: tweak the wiznet driver to allow copying partial chunk
+        //       of received data and use PBUF_POOL.
+        pbuf* pbuf = pbuf_alloc(PBUF_RAW, tot_len, PBUF_RAM);
+        if (!pbuf || pbuf->len < tot_len)
+        {
+            if (pbuf)
+                pbuf_free(pbuf);
+            discardFrame(tot_len);
+            return ERR_BUF;
+        }
+
+        uint16_t len = readFrameData((uint8_t*)pbuf->payload, tot_len);
+        if (len != tot_len)
+        {
+            // tot_len is given by readFrameSize()
+            // and is supposed to be honoured by readFrameData()
+            // todo: ensure this test is unneeded, remove the print
+            Serial.println("read error?\r\n");
             pbuf_free(pbuf);
-        discardFrame(tot_len);
-        return ERR_BUF;
-    }
-
-    uint16_t len = readFrameData((uint8_t*)pbuf->payload, tot_len);
-    if (len != tot_len)
-    {
-        // tot_len is given by readFrameSize()
-        // and is supposed to be honoured by readFrameData()
-        // todo: ensure this test is unneeded, remove the print
-        Serial.println("read error?\r\n");
-        pbuf_free(pbuf);
-        return ERR_BUF;
-    }
+            return ERR_BUF;
+        }
 
-    err_t err = _netif.input(pbuf, &_netif);
+        err_t err = _netif.input(pbuf, &_netif);
 
 #if defined(ESP8266) && PHY_HAS_CAPTURE
-    if (phy_capture)
-        phy_capture(_netif.num, (const char*)pbuf->payload, tot_len, /*out*/0, /*success*/err == ERR_OK);
+        if (phy_capture)
+            phy_capture(_netif.num, (const char*)pbuf->payload, tot_len, /*out*/0, /*success*/err == ERR_OK);
 #endif
 
-    if (err != ERR_OK)
-    {
-        pbuf_free(pbuf);
-        return err;
-    }
-    // (else) allocated pbuf is now on lwIP's responsibility
+        if (err != ERR_OK)
+        {
+            pbuf_free(pbuf);
+            return err;
+        }
+        // (else) allocated pbuf is now on lwIP's responsibility
 
-    return ERR_OK;
+    }
 }
 
 void Wiznet5500lwIP::setDefault ()

w5500-lwIP.h

@@ -21,20 +21,18 @@ class Wiznet5500lwIP: public Wiznet5500 {
 
 public:
 
-    Wiznet5500lwIP (int8_t cs = SS):
+    Wiznet5500lwIP (int8_t cs = SS, int8_t intr = -1):
         Wiznet5500(cs),
         _mtu(DEFAULT_MTU),
-        _default(false)
+        _default(false),
+        _intrPin(intr)
     {
         memset(&_netif, 0, sizeof(_netif));
     }
 
     // start with dhcp client
-    // default mac-address is inferred(+modified) from esp8266's STA one
+    // default mac-address is inferred from esp8266's STA interface
     boolean begin (SPIparam(SPIClass& spi,) const uint8_t *macAddress = nullptr, uint16_t mtu = DEFAULT_MTU);
-    
-    // to be called regularly
-    err_t loop ();
 
     const netif* getNetIf   () const { return &_netif; }
 
@@ -57,14 +55,18 @@ class Wiznet5500lwIP: public Wiznet5500 {
     netif _netif;
     uint16_t _mtu;
     bool _default;
-    
+    int8_t _intrPin;
+
     err_t start_with_dhclient ();
     err_t netif_init ();
     void  netif_status_callback ();
 
     static err_t netif_init_s (netif* netif);
     static err_t linkoutput_s (netif *netif, struct pbuf *p);
     static void  netif_status_callback_s (netif* netif);
+
+    // called on a regular basis or on interrupt
+    err_t handlePackets ();
 };
 
 #endif // W5500LWIP_H