AP_GPS: Check the driver logging health

libraries/AP_GPS/AP_GPS.cpp

@@ -1639,6 +1639,20 @@ bool AP_GPS::prepare_for_arming(void) {
     return all_passed;
 }
 
+bool AP_GPS::logging_failed(void) const {
+    if (!logging_enabled()) {
+        return false;
+    }
+
+    for (uint8_t i = 0; i < GPS_MAX_RECEIVERS; i++) {
+        if ((drivers[i] != nullptr) && !(drivers[i]->logging_healthy())) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
 namespace AP {
 
 AP_GPS &gps()

libraries/AP_GPS/AP_GPS.h

@@ -431,6 +431,12 @@ public:
     // returns true if all GPS instances have passed all final arming checks/state changes
     bool prepare_for_arming(void);
 
+    // returns false if any GPS drivers are not performing their logging appropriately
+    bool logging_failed(void) const;
+
+    bool logging_present(void) const { return _raw_data != 0; }
+    bool logging_enabled(void) const { return _raw_data != 0; }
+
     // used to disable GPS for GPS failure testing in flight
     void force_disable(bool disable) {
         _force_disable_gps = disable;

libraries/AP_GPS/AP_GPS_SBF.cpp

@@ -106,6 +106,17 @@ AP_GPS_SBF::read(void)
     return ret;
 }
 
+bool AP_GPS_SBF::logging_healthy(void) const
+{
+    switch (gps._raw_data) {
+        case 1:
+        default:
+            return (RxState & SBF_DISK_MOUNTED) && (RxState & SBF_DISK_ACTIVITY);
+        case 2:
+            return ((RxState & SBF_DISK_MOUNTED) && (RxState & SBF_DISK_ACTIVITY)) || (!hal.util->get_soft_armed() && _has_been_armed);
+    }
+}
+
 bool
 AP_GPS_SBF::parse(uint8_t temp)
 {

libraries/AP_GPS/AP_GPS_SBF.h

@@ -47,6 +47,8 @@ public:
 
     bool is_healthy(void) const override;
 
+    bool logging_healthy(void) const override;
+
     bool prepare_for_arming(void) override;
 
 

libraries/AP_GPS/GPS_Backend.h

@@ -57,6 +57,8 @@ public:
 
     // driver specific health, returns true if the driver is healthy
     virtual bool is_healthy(void) const { return true; }
+    // returns true if the GPS is doing any logging it is expected to
+    virtual bool logging_healthy(void) const { return true; }
 
     virtual const char *name() const = 0;