Use driver local storage for IRQ request area

Trying not to end up on thedailywtf.com

Author: earlephilhower

cores/rp2040/lwip_wrap.cpp

@@ -828,28 +828,17 @@ extern "C" {
         return __real_ethernet_input(p, netif);
     }
 
-    void lwip_callback(void (*cb)(void *), void *cbData, bool fromISR) {
-#ifdef __FREERTOS
-        if (fromISR) {
-            // In ISR we can't check what the current thread is
-            static __callback_req req = { cb, cbData }; // TODO HACK HERE
-            // We pass in the address of an unknown sized request to the LWIP work queue
-            // For normal mode that address is on the app stack, which will be frozen until
-            // the callback is performed.  So no problem, that stack address will remain valid.
-            // Here, we're in an ISR and won't block, just put a pointer on the queue and
-            // return from the interrupt.  The stack address, there, is no longer safe and you
-            // will see memory corruption when the actual app thread uses its stack.
-            // We can't allocate memory in an IRQ in FreeRTOS, so for now we'll just have
-            // a single heap-based (static) request which will live forever.  As long as
-            // only a single lwip_callback from IRQ is present we're OK.  Should you have 2
-            // IRQ driver network cards, this will fail.
-            // A more satisfying method might have the NIC driver pass in its own class local
-            // preallocated storage space which we can use.
-            __lwip(__callback, &req, fromISR);
+    void lwip_callback(void (*cb)(void *), void *cbData, void *buffer) {
+#ifdef __FREERTOS
+        if (buffer) {
+            __callback_req *req = (__callback_req *)buffer;
+            req->cb = cb;
+            req->cbData = cbData;
+            __lwip(__callback, req, true);
             return;
         } else if (!__isLWIPThread()) {
             __callback_req req = { cb, cbData };
-            __lwip(__callback, &req, fromISR);
+            __lwip(__callback, &req, false);
             return;
         }
 #endif

libraries/lwIP_Ethernet/src/LwipEthernet.cpp

@@ -246,7 +246,7 @@ static void stage2(void *cbData) {
     sys_check_timeouts();
 }
 
-extern "C" void lwip_callback(void (*cb)(void *), void *cbData, bool fromISR);
+#include <lwip_wrap.h>
 static void ethernetTask(void *param) {
     (void) param;
     while (true) {
@@ -255,7 +255,7 @@ static void ethernetTask(void *param) {
             sleep_ms = _pollingPeriod;
         }
         vTaskDelay(sleep_ms / portTICK_PERIOD_MS);
-        lwip_callback(stage2, nullptr, false);
+        lwip_callback(stage2, nullptr);
 #if 0
         // Scan the installed Ethernet drivers
         for (auto handlePacket : _handlePacketList) {

libraries/lwIP_Ethernet/src/LwipIntfDev.h

@@ -72,7 +72,7 @@ enum EthernetLinkStatus {
     LinkOFF
 };
 
-extern "C" void lwip_callback(void (*cb)(void *), void *cbData, bool fromISR);
+#include <lwip_wrap.h>
 
 
 template<class RawDev>
@@ -189,6 +189,7 @@ class LwipIntfDev: public LwipIntf, public RawDev {
     // called on a regular basis or on interrupt
     err_t handlePackets();
     SemaphoreHandle_t _hwMutex;
+    uint8_t _irqBuffer[LWIP_CALLBACK_BUFFER_SIZE];
 protected:
     // members
     SPIClass& _spiUnit;
@@ -483,7 +484,7 @@ template<class RawDev>
 void LwipIntfDev<RawDev>::_irq(void *param) {
     LwipIntfDev *d = static_cast<LwipIntfDev*>(param);
     ethernet_arch_lwip_gpio_mask(); // Disable other IRQs until we're done processing this one
-    lwip_callback(_lwipCallback, param, true);
+    lwip_callback(_lwipCallback, param, (void *)d->_irqBuffer);
     //ethernet_arch_lwip_begin();
 //    d->handlePackets();
 //    sys_check_timeouts();