Refactor Rx code and better support 25Hz links (#13435)

* RX task update rate to 22Hz, to improve 25Hz link stability

* modified Rx code

* add LQ to debug

* use max of frameAge or FrameDelta

* Require a dropouit of 200ms, not 100ms, before RXLOSS

* remove FrameAge, use 150ms timeout 50ms checks

* fix tests and tidy up the comments

* Handle NULL input as before, log frame time

* possible solutions to review comment about names

* Remove rxFrameTimeUs

- prepare for direct use of lastRcFrameTimeUs
- refactor rx_spi callback

* remove global currentRxRateHz

* simplify updateRcRefreshRate

* re-name to recheck interval, return frame time debug

* Calculate RxRate only once

* use rxReceivingSignal for consistency

* use signalReceived not rxDataReceived for consistency

* suggestions from review PL

* move defines, thanks K

* fixes from review, thanks MH

* review changes, undo task interval change

rename bool rxIsReceivingSignal to isRxReceivingSignal
thanks Steve for resolving that tasks changes are not needed
thanks PL for your feedback also

---------

Co-authored-by: Petr Ledvina <ledvinap@hp124.ekotip.cz>

src/test/unit/arming_prevention_unittest.cc

@@ -1051,7 +1051,7 @@ TEST(ArmingPreventionTest, Paralyze)
 extern "C" {
     uint32_t micros(void) { return simulationTime; }
     uint32_t millis(void) { return micros() / 1000; }
-    bool rxIsReceivingSignal(void) { return simulationHaveRx; }
+    bool isRxReceivingSignal(void) { return simulationHaveRx; }
 
     bool featureIsEnabled(uint32_t f) { return simulationFeatureFlags & f; }
     void warningLedFlash(void) {}
@@ -1128,7 +1128,7 @@ extern "C" {
     bool isUpright(void) { return mockIsUpright; }
     void blackboxLogEvent(FlightLogEvent, union flightLogEventData_u *) {};
     void gyroFiltering(timeUs_t) {};
-    timeDelta_t rxGetFrameDelta(timeDelta_t *) { return 0; }
+    timeDelta_t rxGetFrameDelta() { return 0; }
     void updateRcRefreshRate(timeUs_t) {};
     uint16_t getAverageSystemLoadPercent(void) { return 0; }
     bool isMotorProtocolEnabled(void) { return true; }

src/test/unit/blackbox_unittest.cc

@@ -380,7 +380,7 @@ void closeSerialPort(serialPort_t *) {}
 portSharing_e determinePortSharing(const serialPortConfig_t *, serialPortFunction_e ) {return PORTSHARING_UNUSED;}
 failsafePhase_e failsafePhase(void) {return FAILSAFE_IDLE;}
 bool rxAreFlightChannelsValid(void) {return false;}
-bool rxIsReceivingSignal(void) {return false;}
+bool isRxReceivingSignal(void) {return false;}
 bool isRssiConfigured(void) {return false;}
 float getMotorOutputLow(void) {return 0.0;}
 float getMotorOutputHigh(void) {return 0.0;}

src/test/unit/cli_unittest.cc

@@ -387,6 +387,7 @@ bool isModeActivationConditionConfigured(const modeActivationCondition_t *, cons
 void delay(uint32_t) {}
 displayPort_t *osdGetDisplayPort(osdDisplayPortDevice_e *) { return NULL; }
 mcuTypeId_e getMcuTypeId(void) { return MCU_TYPE_UNKNOWN; }
-uint16_t getCurrentRxIntervalUs(void) { return 0; }
+uint16_t getCurrentRxRateHz(void) { return 0; }
 uint16_t getAverageSystemLoadPercent(void) { return 0; }
+bool getRxRateValid(void) { return false; }
 }

src/test/unit/flight_failsafe_unittest.cc

@@ -588,7 +588,7 @@ TEST(FlightFailsafeTest, TestFailsafeSwitchModeStage2Land)
     // when
     failsafeUpdateState();
 
-    // now should be in monitoring mode, with switch holding signalReceived false
+    // now should be in monitoring mode, with switch holding rxDataReceived false
     EXPECT_TRUE(failsafeIsActive());
     EXPECT_EQ(FAILSAFE_RX_LOSS_MONITORING, failsafePhase());
     EXPECT_TRUE(isArmingDisabled());

src/test/unit/ledstrip_unittest.cc

@@ -386,7 +386,7 @@ int scaleRange(int x, int srcMin, int srcMax, int destMin, int destMax)
 }
 
 bool failsafeIsActive() { return false; }
-bool rxIsReceivingSignal() { return true; }
+bool isRxReceivingSignal() { return true; }
 
 bool isBeeperOn() { return false; };
 

src/test/unit/rc_controls_unittest.cc

@@ -622,7 +622,7 @@ void dashboardDisablePageCycling() {}
 void dashboardEnablePageCycling() {}
 
 bool failsafeIsActive() { return false; }
-bool rxIsReceivingSignal() { return true; }
+bool isRxReceivingSignal() { return true; }
 bool failsafeIsReceivingRxData() { return true; }
 
 uint8_t getCurrentControlRateProfileIndex(void)

src/test/unit/vtx_unittest.cc

@@ -130,7 +130,7 @@ extern "C" {
     uint8_t activePidLoopDenom = 1;
     uint32_t micros(void) { return simulationTime; }
     uint32_t millis(void) { return micros() / 1000; }
-    bool rxIsReceivingSignal(void) { return simulationHaveRx; }
+    bool isRxReceivingSignal(void) { return simulationHaveRx; }
 
     bool featureIsEnabled(uint32_t f) { return simulationFeatureFlags & f; }
     void warningLedFlash(void) {}
@@ -202,7 +202,7 @@ extern "C" {
     bool isUpright(void) { return true; }
     void blackboxLogEvent(FlightLogEvent, union flightLogEventData_u *) {};
     void gyroFiltering(timeUs_t) {};
-    timeDelta_t rxGetFrameDelta(timeDelta_t *) { return 0; }
+    timeDelta_t rxGetFrameDelta() { return 0; }
     void updateRcRefreshRate(timeUs_t) {};
     uint16_t getAverageSystemLoadPercent(void) { return 0; }
     bool isMotorProtocolEnabled(void) { return false; }