Implement override of default RTS/DTR behavior for DVM-V24-V2 boards with hardware boot control. (#77)

* initial work to support DVM-V24 RTS/DTR boot modes

* whoops forgot to remove this debug print

---------

Co-authored-by: W3AXL <29879554+W3AXL@users.noreply.github.com>

src/host/Host.Config.cpp

@@ -552,12 +552,17 @@ bool Host::createModem()
         }
 
         if (portType == PTY_PORT) {
-            modemPort = new port::UARTPort(uartPort, serialSpeed, false);
+            modemPort = new port::UARTPort(uartPort, serialSpeed, false, false);
             LogInfo("    PTY Port: %s", uartPort.c_str());
             LogInfo("    PTY Speed: %u", uartSpeed);
         }
         else {
-            modemPort = new port::UARTPort(uartPort, serialSpeed, true);
+            if (modemMode == MODEM_MODE_DFSI) {
+                modemPort = new port::UARTPort(uartPort, serialSpeed, false, true);
+                LogInfo("    RTS/DTR boot flags enabled");
+            } else {
+                modemPort = new port::UARTPort(uartPort, serialSpeed, true, false);
+            }
             LogInfo("    UART Port: %s", uartPort.c_str());
             LogInfo("    UART Speed: %u", uartSpeed);
         }

src/host/modem/port/PseudoPTYPort.cpp

@@ -30,7 +30,7 @@ using namespace modem::port;
 
 /* Initializes a new instance of the PseudoPTYPort class. */
 
-PseudoPTYPort::PseudoPTYPort(const std::string& symlink, SERIAL_SPEED speed, bool assertRTS) : UARTPort(speed, assertRTS),
+PseudoPTYPort::PseudoPTYPort(const std::string& symlink, SERIAL_SPEED speed, bool assertRTS) : UARTPort(speed, assertRTS, false),
     m_symlink(symlink)
 {
     /* stub */

src/host/modem/port/UARTPort.cpp

@@ -37,11 +37,12 @@ using namespace modem::port;
 
 /* Initializes a new instance of the UARTPort class. */
 
-UARTPort::UARTPort(const std::string& device, SERIAL_SPEED speed, bool assertRTS) :
+UARTPort::UARTPort(const std::string& device, SERIAL_SPEED speed, bool assertRTS, bool rtsBoot) :
     m_isOpen(false),
     m_device(device),
     m_speed(speed),
     m_assertRTS(assertRTS),
+    m_rtsBoot(rtsBoot),
 #if defined(_WIN32)
     m_fd(INVALID_HANDLE_VALUE)
 #else
@@ -334,10 +335,11 @@ int UARTPort::setNonblock(bool nonblock)
 
 /* Initializes a new instance of the UARTPort class. */
 
-UARTPort::UARTPort(SERIAL_SPEED speed, bool assertRTS) :
+UARTPort::UARTPort(SERIAL_SPEED speed, bool assertRTS, bool rtsBoot) :
     m_isOpen(false),
     m_speed(speed),
     m_assertRTS(assertRTS),
+    m_rtsBoot(rtsBoot),
 #if defined(_WIN32)
     m_fd(INVALID_HANDLE_VALUE)
 #else
@@ -500,6 +502,40 @@ bool UARTPort::setTermios()
         }
     }
 
+    // Special setting of RTS/DTR for DVM-V24 boards with onboard DTR/RTS boot connections
+    if (m_rtsBoot) {
+        ::LogInfoEx(LOG_MODEM, "RTS/DTR boot flag enabled, forcing board reset");
+        uint32_t y;
+        if (::ioctl(m_fd, TIOCMGET, &y) < 0) {
+            ::LogError(LOG_HOST, "Cannot get the control attributes for %s", m_device.c_str());
+            ::close(m_fd);
+            return false;
+        }
+
+        // Force RTS bit off
+        y &= ~TIOCM_RTS;
+
+        if (::ioctl(m_fd, TIOCMSET, &y) < 0) {
+            ::LogError(LOG_HOST, "Cannot set the control attributes for %s", m_device.c_str());
+            ::close(m_fd);
+            return false;
+        }
+
+        // Toggle DTR to force second reset
+        y &= ~TIOCM_DTR;
+        if (::ioctl(m_fd, TIOCMSET, &y) < 0) {
+            ::LogError(LOG_HOST, "Cannot set the control attributes for %s", m_device.c_str());
+            ::close(m_fd);
+            return false;
+        }
+        y |= TIOCM_DTR;
+        if (::ioctl(m_fd, TIOCMSET, &y) < 0) {
+            ::LogError(LOG_HOST, "Cannot set the control attributes for %s", m_device.c_str());
+            ::close(m_fd);
+            return false;
+        }
+    }
+
 #if defined(__APPLE__)
     setNonblock(false);
 #endif

src/host/modem/port/UARTPort.h

@@ -76,7 +76,7 @@ namespace modem
              * @param speed Serial port speed.
              * @param assertRTS 
              */
-            UARTPort(const std::string& device, SERIAL_SPEED speed, bool assertRTS = false);
+            UARTPort(const std::string& device, SERIAL_SPEED speed, bool assertRTS = false, bool rtsBoot = false);
             /**
              * @brief Finalizes a instance of the UARTPort class.
              */
@@ -122,13 +122,14 @@ namespace modem
              * @param speed Serial port speed.
              * @param assertRTS 
              */
-            UARTPort(SERIAL_SPEED speed, bool assertRTS = false);
+            UARTPort(SERIAL_SPEED speed, bool assertRTS = false, bool rtsBoot = false);
 
             bool m_isOpen;
 
             std::string m_device;
             SERIAL_SPEED m_speed;
             bool m_assertRTS;
+            bool m_rtsBoot;
 #if defined(_WIN32)
             HANDLE m_fd;
 #else