From cdccc67fb8452afbe11599032a688691f26fb510 Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Tue, 9 Nov 2021 17:23:34 +1100
Subject: [PATCH] AP_HAL_SITL: make SITL::ADSB a SITL::SerialDevice

---
 libraries/AP_HAL_SITL/SITL_State.cpp | 19 +++++++++----------
 libraries/AP_HAL_SITL/UARTDriver.cpp | 10 ++++++++++
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/libraries/AP_HAL_SITL/SITL_State.cpp b/libraries/AP_HAL_SITL/SITL_State.cpp
index e7ec21e1b4..ceba411f2a 100644
--- a/libraries/AP_HAL_SITL/SITL_State.cpp
+++ b/libraries/AP_HAL_SITL/SITL_State.cpp
@@ -168,15 +168,6 @@ void SITL_State::_fdm_input_step(void)
     if (_sitl != nullptr) {
         _update_airspeed(_sitl->state.airspeed);
         _update_rangefinder(_sitl->state.range);
-
-        if (_sitl->adsb_plane_count >= 0 &&
-            adsb == nullptr) {
-            adsb = new SITL::ADSB(_sitl->state, sitl_model->get_home(), get_instance());
-        } else if (_sitl->adsb_plane_count == -1 &&
-                   adsb != nullptr) {
-            delete adsb;
-            adsb = nullptr;
-        }
     }
 
     // trigger all APM timers.
@@ -220,6 +211,14 @@ SITL::SerialDevice *SITL_State::create_serial_sim(const char *name, const char *
         }
         vicon = new SITL::Vicon();
         return vicon;
+    } else if (streq(name, "adsb")) {
+        // ADSB is a stand-out as it is the only serial device which
+        // will cope with begin() being called multiple times on a
+        // serial port
+        if (adsb == nullptr) {
+            adsb = new SITL::ADSB();
+        }
+        return adsb;
     } else if (streq(name, "benewake_tf02")) {
         if (benewake_tf02 != nullptr) {
             AP_HAL::panic("Only one benewake_tf02 at a time");
@@ -534,7 +533,7 @@ void SITL_State::_fdm_input_local(void)
         gimbal->update();
     }
     if (adsb != nullptr) {
-        adsb->update();
+        adsb->update(*sitl_model);
     }
     if (vicon != nullptr) {
         Quaternion attitude;
diff --git a/libraries/AP_HAL_SITL/UARTDriver.cpp b/libraries/AP_HAL_SITL/UARTDriver.cpp
index 2cf9cfb0b7..5ac7761bcf 100644
--- a/libraries/AP_HAL_SITL/UARTDriver.cpp
+++ b/libraries/AP_HAL_SITL/UARTDriver.cpp
@@ -89,6 +89,16 @@ void UARTDriver::begin(uint32_t baud, uint16_t rxSpace, uint16_t txSpace)
         char *devtype = strtok_r(s, ":", &saveptr);
         char *args1 = strtok_r(nullptr, ":", &saveptr);
         char *args2 = strtok_r(nullptr, ":", &saveptr);
+#if !defined(HAL_BUILD_AP_PERIPH)
+        if (_portNumber == 2 && AP::sitl()->adsb_plane_count >= 0) {
+            // this is ordinarily port 5762.  The ADSB simulation assumed
+            // this port, so if enabled we assume we'll be doing ADSB...
+            // add sanity check here that we're doing mavlink on this port?
+            ::printf("SIM-ADSB connection on port %u\n", _portNumber);
+            _connected = true;
+            _sim_serial_device = _sitlState->create_serial_sim("adsb", nullptr);
+        } else
+#endif
         if (strcmp(devtype, "tcp") == 0) {
             uint16_t port = atoi(args1);
             bool wait = (args2 && strcmp(args2, "wait") == 0);