From 952ccb68c47198ff23ef64e841cdfd2b09f14d0e Mon Sep 17 00:00:00 2001
From: Petr Ledvina <ledvinap@gmail.com>
Date: Fri, 6 Sep 2024 09:46:51 +0200
Subject: [PATCH] cli - fix gpspassthrouh when GPS port is not open (#13878)

- return status from gpsPassthrough
- test gpsPort
---
 src/main/cli/cli.c |  4 +++-
 src/main/io/gps.c  | 15 +++++++++++++--
 src/main/io/gps.h  |  2 +-
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/main/cli/cli.c b/src/main/cli/cli.c
index b380e2c47c8..993b77ad208 100644
--- a/src/main/cli/cli.c
+++ b/src/main/cli/cli.c
@@ -3603,7 +3603,9 @@ static void cliGpsPassthrough(const char *cmdName, char *cmdline)
     UNUSED(cmdName);
     UNUSED(cmdline);
 
-    gpsEnablePassthrough(cliPort);
+    if (!gpsPassthrough(cliPort)) {
+        cliPrintErrorLinef(cmdName, "GPS forwarding failed");
+    }
 }
 #endif
 
diff --git a/src/main/io/gps.c b/src/main/io/gps.c
index 883ec7952cc..299e594b65b 100644
--- a/src/main/io/gps.c
+++ b/src/main/io/gps.c
@@ -2486,13 +2486,22 @@ static void gpsHandlePassthrough(uint8_t data)
 #endif
 }
 
-void gpsEnablePassthrough(serialPort_t *gpsPassthroughPort)
+// forward GPS data to specified port (used by CLI)
+// return false if forwarding failed
+// curently only way to stop forwarding is to reset the board
+bool gpsPassthrough(serialPort_t *gpsPassthroughPort)
 {
+    if (!gpsPort) {
+        // GPS port is not open for some reason - no GPS, MSP GPS, ..
+        return false;
+    }
     waitForSerialPortToFinishTransmitting(gpsPort);
     waitForSerialPortToFinishTransmitting(gpsPassthroughPort);
 
-    if (!(gpsPort->mode & MODE_TX))
+    if (!(gpsPort->mode & MODE_TX)) {
+        // try to switch TX mode on
         serialSetMode(gpsPort, gpsPort->mode | MODE_TX);
+    }
 
 #ifdef USE_DASHBOARD
     if (featureIsEnabled(FEATURE_DASHBOARD)) {
@@ -2502,6 +2511,8 @@ void gpsEnablePassthrough(serialPort_t *gpsPassthroughPort)
 #endif
 
     serialPassthrough(gpsPort, gpsPassthroughPort, &gpsHandlePassthrough, NULL);
+    // allow exitting passthrough mode in future
+    return true;
 }
 
 float GPS_cosLat = 1.0f;  // this is used to offset the shrinking longitude as we go towards the poles
diff --git a/src/main/io/gps.h b/src/main/io/gps.h
index fbfa12fb1e0..66153393d40 100644
--- a/src/main/io/gps.h
+++ b/src/main/io/gps.h
@@ -386,7 +386,7 @@ void gpsUpdate(timeUs_t currentTimeUs);
 bool gpsNewFrame(uint8_t c);
 bool gpsIsHealthy(void); // Returns true when the gps state is RECEIVING_DATA
 struct serialPort_s;
-void gpsEnablePassthrough(struct serialPort_s *gpsPassthroughPort);
+bool gpsPassthrough(struct serialPort_s *gpsPassthroughPort);
 void onGpsNewData(void);
 void GPS_reset_home_position(void);
 void GPS_calc_longitude_scaling(int32_t lat);