From 15d1cdc52677db61eb2806e649f7bc84a39b4287 Mon Sep 17 00:00:00 2001
From: Adam Novak <interfect@gmail.com>
Date: Wed, 16 Feb 2022 21:02:49 -0500
Subject: [PATCH] Poll for packets

---
 LoRa.cpp           | 55 ++++++++++++++++++++++++++++++----------------
 LoRa.h             |  2 ++
 RNode_Firmware.ino |  6 +++++
 3 files changed, 44 insertions(+), 19 deletions(-)

diff --git a/LoRa.cpp b/LoRa.cpp
index c320f00..f95a92f 100644
--- a/LoRa.cpp
+++ b/LoRa.cpp
@@ -394,6 +394,19 @@ void LoRaClass::flush()
 {
 }
 
+void LoRaClass::pollReceive()
+{
+  int irqFlags = readRegister(REG_IRQ_FLAGS);
+
+  // clear IRQ's
+  writeRegister(REG_IRQ_FLAGS, irqFlags);
+
+  if ((irqFlags & IRQ_RX_DONE_MASK) && !(irqFlags & IRQ_PAYLOAD_CRC_ERROR_MASK)) {
+    // received a packet
+    handleRx();
+  }
+}
+
 void LoRaClass::onReceive(void(*callback)(int))
 {
   _onReceive = callback;
@@ -404,17 +417,15 @@ void LoRaClass::onReceive(void(*callback)(int))
 #endif
 
     writeRegister(REG_DIO_MAPPING_1, 0x00);
-    
-#if LIBRARY_TYPE == LIBRARY_ARDUINO
+
+#if MCU_VARIANT != MCU_LINUX && LIBRARY_TYPE == LIBRARY_ARDUINO
 #ifdef SPI_HAS_NOTUSINGINTERRUPT
     SPI.usingInterrupt(digitalPinToInterrupt(_dio0));
 #endif
     attachInterrupt(digitalPinToInterrupt(_dio0), LoRaClass::onDio0Rise, RISING);
 #endif
-    // TODO: What do we do if we want to use C library with a board that
-    // actually has dio0 connected?  
   } else {
-#if LIBRARY_TYPE == LIBRARY_ARDUINO
+#if MCU_VARIANT != MCU_LINUX && LIBRARY_TYPE == LIBRARY_ARDUINO
     detachInterrupt(digitalPinToInterrupt(_dio0));
 #ifdef SPI_HAS_NOTUSINGINTERRUPT
     SPI.notUsingInterrupt(digitalPinToInterrupt(_dio0));
@@ -670,23 +681,29 @@ void ISR_VECT LoRaClass::handleDio0Rise()
 
   if ((irqFlags & IRQ_PAYLOAD_CRC_ERROR_MASK) == 0) {
     // received a packet
-    _packetIndex = 0;
-
-    // read packet length
-    int packetLength = _implicitHeaderMode ? readRegister(REG_PAYLOAD_LENGTH) : readRegister(REG_RX_NB_BYTES);
-
-    // set FIFO address to current RX address
-    writeRegister(REG_FIFO_ADDR_PTR, readRegister(REG_FIFO_RX_CURRENT_ADDR));
-
-    if (_onReceive) {
-      _onReceive(packetLength);
-    }
-
-    // reset FIFO address
-    writeRegister(REG_FIFO_ADDR_PTR, 0);
+    handleRx();
   }
 }
 
+void ISR_VECT LoRaClass::handleRx()
+{
+  // received a packet
+  _packetIndex = 0;
+
+  // read packet length
+  int packetLength = _implicitHeaderMode ? readRegister(REG_PAYLOAD_LENGTH) : readRegister(REG_RX_NB_BYTES);
+
+  // set FIFO address to current RX address
+  writeRegister(REG_FIFO_ADDR_PTR, readRegister(REG_FIFO_RX_CURRENT_ADDR));
+
+  if (_onReceive) {
+    _onReceive(packetLength);
+  }
+
+  // reset FIFO address
+  writeRegister(REG_FIFO_ADDR_PTR, 0);
+}
+
 uint8_t ISR_VECT LoRaClass::readRegister(uint8_t address)
 {
   return singleTransfer(address & 0x7f, 0x00);
diff --git a/LoRa.h b/LoRa.h
index a418efe..b784f27 100644
--- a/LoRa.h
+++ b/LoRa.h
@@ -76,6 +76,7 @@ public:
   virtual int peek();
   virtual void flush();
 
+  void pollReceive();
   void onReceive(void(*callback)(int));
 
   void receive(int size = 0);
@@ -115,6 +116,7 @@ private:
   void implicitHeaderMode();
 
   void handleDio0Rise();
+  void handleRx();
 
   uint8_t readRegister(uint8_t address);
   void writeRegister(uint8_t address, uint8_t value);
diff --git a/RNode_Firmware.ino b/RNode_Firmware.ino
index 5e8af06..b444e64 100644
--- a/RNode_Firmware.ino
+++ b/RNode_Firmware.ino
@@ -778,6 +778,12 @@ void loop() {
         kiss_write_packet();
       }
     #endif
+    
+    #if MCU_VARIANT == MCU_LINUX
+      // We don't have interrupts, so we need to poll ofr received packets.
+      // TODO: Is this fast enough? Or do we need threads or something?
+      LoRa.pollReceive(); 
+    #endif
 
     if (queue_height > 0) {
       if (!dcd_waiting) updateModemStatus();