From 04c8523619ebac17a96bf6f97c9daaf9567e49cd Mon Sep 17 00:00:00 2001
From: Adam Novak <interfect@gmail.com>
Date: Tue, 15 Feb 2022 22:00:13 -0500
Subject: [PATCH] Implement Serial

---
 LoRa.cpp    |  8 +++++--
 Makefile    |  2 +-
 Utilities.h | 63 ++++++++++++++++++++++++++++++++++++++++-------------
 3 files changed, 55 insertions(+), 18 deletions(-)

diff --git a/LoRa.cpp b/LoRa.cpp
index 4788eba..8cba9e1 100644
--- a/LoRa.cpp
+++ b/LoRa.cpp
@@ -125,8 +125,10 @@ int LoRaClass::begin(long frequency)
   // start SPI
   SPI.begin();
 #elif LIBRARY_TYPE == LIBRARY_C
-  _fd = open("/dev/spidev0.0", O_RDWR);
-  if (_fd < 0) {
+  const char* spi_filename = "/dev/spidev0.0";
+  std::cerr << "Opening SPI device " << spi_filename << std::endl;
+  _fd = open(spi_filename, O_RDWR);
+  if (_fd <= 0) {
     perror("could not open SPI device");
     exit(1);
   }
@@ -703,6 +705,8 @@ uint8_t ISR_VECT LoRaClass::singleTransfer(uint8_t address, uint8_t value)
   
   int status;
   
+  std::cerr << "Access SPI at " << _fd << std::endl;
+  
   // Configure SPI speed and mode to match settings
   status = ioctl(_fd, SPI_IOC_WR_MODE, &_spiSettings.mode);
   if (status < 0) {
diff --git a/Makefile b/Makefile
index 040edd1..80e4659 100644
--- a/Makefile
+++ b/Makefile
@@ -152,4 +152,4 @@ obj/RNode_Firmware.o: RNode_Firmware.ino Utilities.h Config.h LoRa.h ROM.h Frami
 	
 bin/rnode: obj/RNode_Firmware.o obj/LoRa.o obj/MD5.o
 	mkdir -p bin
-	$(CC) -o $@ $^ -lstdc++
+	$(CC) -o $@ $^ -lstdc++ -lutil
diff --git a/Utilities.h b/Utilities.h
index f150f7a..3f07bbf 100644
--- a/Utilities.h
+++ b/Utilities.h
@@ -10,6 +10,9 @@
 
 #if LIBRARY_TYPE == LIBRARY_C
   #include <time.h>
+  #include <poll.h>
+  #include <unistd.h>
+  #include <pty.h>
   // We need a delay()
   void delay(int ms) {
     struct timespec interval;
@@ -40,39 +43,69 @@
   // We also need a Serial
   class SerialClass {
   public:
-    const char* fifoPath = "rnode_socket";
     void begin(int baud) {
-      int status = mkfifo(fifoPath, 0666);
+      int other_end = 0;
+      int status = openpty(&_fd, &other_end, NULL, NULL, NULL); 
       if (status) {
-        perror("Making fifo failed");
-        exit(1);
-      }
-      // TODO: Need a bidirectional thing here: openpty???
-      _fd = open(fifoPath, O_RDWR);
-      if (_fd < 0) {
-        perror("could not open fifo");
+        perror("could not open PTY");
         exit(1);
       }
+      
+      std::cout << "Listening on " << ttyname(other_end) << std::endl;
     }
-    // Be truthy if connected
+    
     operator bool() {
       return _fd > 0; 
     }
     void write(int b) {
-      ssize_t written = ::write(_fd, 
+      uint8_t to_write = b;
+      ssize_t written = ::write(_fd, &to_write, 1);
+      while (written != 1) {
+        if (written < 0) {
+          perror("could not write to PTY");
+          exit(1);
+        }
+        written = ::write(_fd, &to_write, 1);
+      }
     }
     void write(const char* data) {
-      throw std::runtime_error("Unimplemented");
+      while(*data) {
+        write(*data);
+        ++data;
+      }
     }
     bool available() {
-      throw std::runtime_error("Unimplemented");
+      struct pollfd request;
+      request.fd = _fd;
+      request.events = POLLIN;
+      request.revents = 0;
+      
+      int result = poll(&request, 1, 0);
+      
+      if (result == -1) {
+        perror("could not poll");
+        exit(1);
+      }
+      
+      return result > 0;
     }
     uint8_t read() {
-      throw std::runtime_error("Unimplemented");
+      uint8_t buffer;
+      ssize_t count = ::read(_fd, &buffer, 1);
+      while (count != 1) {
+        if (count < 0) {
+          perror("could not read from PTY");
+          exit(1);
+        }
+        count = ::read(_fd, &buffer, 1);
+      }
+      return buffer;
     }
   protected:
-    int _fd = -1;
+    int _fd;
   };
+  
+  
   SerialClass Serial;
   
   // And random(below);