Use callback from LWIP thread to process Ethernet

Deadlocks/pauses  seem to be unavoidable when running Ethernet packet
receive outside of the LWIP thread.

Add a callback queue message to the LWIP thread to allow for it to
run whatever ethernet processing needed.  These messages still get stuffed
by another simple periodic task.

Author: earlephilhower

cores/rp2040/freertos/variantHooks.cpp

@@ -578,15 +578,13 @@ extern "C" bool __isLWIPThread() {
     return t.xHandle == __lwipTask;
 }
 
-
 static void lwipThread(void *params) {
     (void) params;
     LWIPWork w;
     assert(__isLWIPThread());
 
     while (true) {
         if (xQueueReceive(__lwipQueue, &w, portMAX_DELAY)) {
-            printf("+LWIPTHREAD %p\n", w.wakeup);
             switch (w.op) {
                 case __lwip_init:
                 {
@@ -931,6 +929,12 @@ static void lwipThread(void *params) {
                     *(r->ret) = __real_ethernet_input(r->p, r->netif);
                     break;
                 }
+                case __callback:
+                {
+                    __callback_req *r = (__callback_req *)w.req;
+                    r->cb();
+                    break;
+                }
                 default:
                 {
                     // Any new unimplemented calls = ERROR!!!
@@ -939,7 +943,6 @@ static void lwipThread(void *params) {
                 }
             }
             // Work done, return value set, just tickle the calling task
-            printf("-LWIPTHREAD %p\n", w.wakeup);
             xTaskNotifyGiveIndexed(w.wakeup, TASK_NOTIFY_LWIP_WAKEUP);
         }
     }

cores/rp2040/lwip_wrap.cpp

@@ -829,5 +829,17 @@ extern "C" {
         return __real_ethernet_input(p, netif);
     }
 
+    void lwip_callback(void (*cb)()) {
+#ifdef __FREERTOS
+        if (!__isLWIPThread()) {
+            __callback_req req = { cb };
+            __lwip(__callback, &req);
+            return;
+        }
+#endif
+        cb();
+        return;
+    }
+
 
 }; // extern "C"

libraries/lwIP_Ethernet/src/LwipEthernet.cpp

@@ -233,6 +233,16 @@ static void update_next_timeout(async_context_t *context, async_when_pending_wor
 // and polls all Ethernet interfaces
 static TaskHandle_t _ethernetTask;;
 
+static void stage2() {
+        // Scan the installed Ethernet drivers
+        for (auto handlePacket : _handlePacketList) {
+            // Note that each NIC needs to use its own mutex to ensure LWIP isn't doing something with it at the time we want to poll
+            handlePacket.second();
+        }
+        // Do LWIP stuff as needed
+        sys_check_timeouts();
+}
+extern "C" void lwip_callback(void (*cb)());
 static void ethernetTask(void *param) {
     (void) param;
     while (true) {
@@ -241,13 +251,16 @@ static void ethernetTask(void *param) {
             sleep_ms = _pollingPeriod;
         }
         vTaskDelay(sleep_ms / portTICK_PERIOD_MS);
+        lwip_callback(stage2);
+#if 0
         // Scan the installed Ethernet drivers
         for (auto handlePacket : _handlePacketList) {
             // Note that each NIC needs to use its own mutex to ensure LWIP isn't doing something with it at the time we want to poll
             handlePacket.second();
         }
         // Do LWIP stuff as needed
         sys_check_timeouts();
+#endif
     }
 }
 

libraries/lwIP_Ethernet/src/LwipIntfDev.h

@@ -581,14 +581,13 @@ err_t LwipIntfDev<RawDev>::handlePackets() {
         {
             return ERR_OK;
         }
-printf("handlePackets1\n");
+
         xSemaphoreTake(_hwMutex, portMAX_DELAY);
         uint16_t tot_len = RawDev::readFrameSize();
         if (!tot_len) {
             xSemaphoreGive(_hwMutex);
             return ERR_OK;
         }
-printf("handlePackets2\n");
 
         // from doc: use PBUF_RAM for TX, PBUF_POOL from RX
         // however:
@@ -599,7 +598,6 @@ printf("handlePackets2\n");
         // 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);
-        printf("pballoc ret %p\n", pbuf);
         if (!pbuf || pbuf->len < tot_len) {
             if (pbuf) {
                 pbuf_free(pbuf);
@@ -620,9 +618,9 @@ printf("handlePackets2\n");
         }
 
         _packetsReceived++;
-printf("recv pkt %d: ", tot_len);
-for (int i=0; i < tot_len; i++)  printf("%02x ", ((uint8_t*)pbuf->payload)[i]);
-printf("\n");
+//printf("recv pkt %d: ", tot_len);
+//for (int i=0; i < tot_len; i++)  printf("%02x ", ((uint8_t*)pbuf->payload)[i]);
+//printf("\n");
         err_t err = _netif.input(pbuf, &_netif);
 
 #if PHY_HAS_CAPTURE