Improve performance for ELRS SX1280 SPI callbacks and SPI/ELRS handlers. (#11460)

* SPI - Mark the SPI IRQ handler as FAST_IRQ_HANDLER.

Since it's used by both the gyro code, at 8k (or 2x8k on dual gyro
boards) having it in RAM removes a significant amount of potential flash
latency.

It is also used by the ELRS SPI code.  The ELRS code runs at 500hz, but
each cycle uses multiple SPI transfers, for clear irq, read,
start-recieving, change-frequency, etc. I.e. invokd at least 1000hz in
addition to gyro reads.

* ELRS - Move some frequently used functions to RAM and mark some irq
handlers as FAST.

* SPI/LL - Move some frequently called code to FAST_CODE.

Also remove some invalid characters that Eclipse with encoding as UTF-8
complained about.

* SPI - Mark the spiRx and spiTx dma handlers as FAST_IRQ_HANDLER.

* Filter - move nullFilterApply out of FAST_CODE.

Since it doesn't do anything, it doesn't need to be fast.  Instead we
keep more `fast` RAM for other code that really benefits from being in
fast RAM.

There is a slight penalty to jump into slower RAM.

* Gyro - Move `performGyroCalibration`out of 'fast' ram.

On F7X2 it was being inlined, saved 478 bytes of ITCM.

* Prevent handling of crash recovery handling, not detection of crash
recovery, from being inlined to save ITCM for code that runs more
frequently.

src/main/common/filter.c

@@ -33,7 +33,7 @@
 
 // NULL filter
 
-FAST_CODE float nullFilterApply(filter_t *filter, float input)
+float nullFilterApply(filter_t *filter, float input)
 {
     UNUSED(filter);
     return input;

src/main/drivers/bus_spi.c

@@ -378,7 +378,7 @@ uint32_t spiCalculateClock(uint16_t spiClkDivisor)
 }
 
 // Interrupt handler for SPI receive DMA completion
-static void spiIrqHandler(const extDevice_t *dev)
+FAST_IRQ_HANDLER static void spiIrqHandler(const extDevice_t *dev)
 {
     busDevice_t *bus = dev->bus;
     busSegment_t *nextSegment;
@@ -447,7 +447,7 @@ static void spiIrqHandler(const extDevice_t *dev)
 }
 
 // Interrupt handler for SPI receive DMA completion
-static void spiRxIrqHandler(dmaChannelDescriptor_t* descriptor)
+FAST_IRQ_HANDLER static void spiRxIrqHandler(dmaChannelDescriptor_t* descriptor)
 {
     const extDevice_t *dev = (const extDevice_t *)descriptor->userParam;
 
@@ -484,7 +484,7 @@ static void spiRxIrqHandler(dmaChannelDescriptor_t* descriptor)
 
 #if !defined(STM32G4) && !defined(STM32H7)
 // Interrupt handler for SPI transmit DMA completion
-static void spiTxIrqHandler(dmaChannelDescriptor_t* descriptor)
+FAST_IRQ_HANDLER static void spiTxIrqHandler(dmaChannelDescriptor_t* descriptor)
 {
     const extDevice_t *dev = (const extDevice_t *)descriptor->userParam;
 

src/main/drivers/bus_spi_ll.c

@@ -225,7 +225,7 @@ void spiInternalResetStream(dmaChannelDescriptor_t *descriptor)
 }
 
 
-static bool spiInternalReadWriteBufPolled(SPI_TypeDef *instance, const uint8_t *txData, uint8_t *rxData, int len)
+FAST_CODE static bool spiInternalReadWriteBufPolled(SPI_TypeDef *instance, const uint8_t *txData, uint8_t *rxData, int len)
 {
 #if defined(STM32H7)
     LL_SPI_SetTransferSize(instance, len);
@@ -424,7 +424,7 @@ void spiInternalStartDMA(const extDevice_t *dev)
 
         /* Note from AN4031
          *
-         * If the user enables the used peripheral before the corresponding DMA stream, a “FEIF”
+         * If the user enables the used peripheral before the corresponding DMA stream, a FEIF
          * (FIFO Error Interrupt Flag) may be set due to the fact the DMA is not ready to provide
          * the first required data to the peripheral (in case of memory-to-peripheral transfer).
          */
@@ -464,7 +464,7 @@ void spiInternalStartDMA(const extDevice_t *dev)
 
         /* Note from AN4031
          *
-         * If the user enables the used peripheral before the corresponding DMA stream, a “FEIF”
+         * If the user enables the used peripheral before the corresponding DMA stream, a FEIF
          * (FIFO Error Interrupt Flag) may be set due to the fact the DMA is not ready to provide
          * the first required data to the peripheral (in case of memory-to-peripheral transfer).
          */
@@ -533,7 +533,7 @@ void spiInternalStopDMA (const extDevice_t *dev)
 }
 
 // DMA transfer setup and start
-void spiSequenceStart(const extDevice_t *dev)
+FAST_CODE void spiSequenceStart(const extDevice_t *dev)
 {
     busDevice_t *bus = dev->bus;
     SPI_TypeDef *instance = bus->busType_u.spi.instance;

src/main/drivers/rx/rx_sx1280.c

@@ -77,7 +77,7 @@ bool sx1280IsBusy(void)
     return IORead(busy);
 }
 
-static bool sx1280PollBusy(void)
+FAST_CODE static bool sx1280PollBusy(void)
 {
     uint32_t startTime = micros();
     while (IORead(busy)) {
@@ -90,7 +90,7 @@ static bool sx1280PollBusy(void)
     return true;
 }
 
-static bool sx1280MarkBusy(void)
+FAST_CODE static bool sx1280MarkBusy(void)
 {
     // Check that there isn't already a sequence of accesses to the SX1280 in progress
     ATOMIC_BLOCK(NVIC_PRIO_MAX) {
@@ -110,7 +110,7 @@ static void sx1280ClearBusyFn(void)
 }
 
 // Switch to waiting for busy interrupt
-static bool sx1280EnableBusy(void)
+FAST_CODE static bool sx1280EnableBusy(void)
 {
     if (!sx1280MarkBusy()) {
         return false;
@@ -569,7 +569,7 @@ static void sx1280SendTelemetryBuffer(extiCallbackRec_t *cb);
 static busStatus_e sx1280TelemetryComplete(uint32_t arg);
 static void sx1280StartTransmittingDMA(extiCallbackRec_t *cb);
 
-void sx1280ISR(void)
+FAST_IRQ_HANDLER void sx1280ISR(void)
 {
     // Only attempt to access the SX1280 if it is currently idle to avoid any race condition
     ATOMIC_BLOCK(NVIC_PRIO_MAX) {
@@ -584,7 +584,7 @@ void sx1280ISR(void)
 
 // Next, the reason for the IRQ must be read
 
-static void sx1280IrqGetStatus(extiCallbackRec_t *cb)
+FAST_IRQ_HANDLER static void sx1280IrqGetStatus(extiCallbackRec_t *cb)
 {
     extDevice_t *dev = rxSpiGetDevice();
 
@@ -605,7 +605,7 @@ static void sx1280IrqGetStatus(extiCallbackRec_t *cb)
 
 // Read the IRQ status, and save it to irqStatus variable
 
-static busStatus_e sx1280IrqStatusRead(uint32_t arg)
+FAST_IRQ_HANDLER static busStatus_e sx1280IrqStatusRead(uint32_t arg)
 {
     extDevice_t *dev = (extDevice_t *)arg;
 
@@ -625,7 +625,7 @@ static busStatus_e sx1280IrqStatusRead(uint32_t arg)
 
 // Clear the IRQ bit in the Radio registers
 
-static void sx1280IrqClearStatus(extiCallbackRec_t *cb)
+FAST_IRQ_HANDLER static void sx1280IrqClearStatus(extiCallbackRec_t *cb)
 {
     extDevice_t *dev = rxSpiGetDevice();
 
@@ -647,7 +647,7 @@ static void sx1280IrqClearStatus(extiCallbackRec_t *cb)
 }
 
 // Callback follow clear of IRQ status
-static busStatus_e sx1280IrqCmdComplete(uint32_t arg)
+FAST_IRQ_HANDLER static busStatus_e sx1280IrqCmdComplete(uint32_t arg)
 {
     UNUSED(arg);
 
@@ -657,7 +657,7 @@ static busStatus_e sx1280IrqCmdComplete(uint32_t arg)
 }
 
 // Process IRQ status
-static void sx1280ProcessIrq(extiCallbackRec_t *cb)
+FAST_IRQ_HANDLER static void sx1280ProcessIrq(extiCallbackRec_t *cb)
 {
     extDevice_t *dev = rxSpiGetDevice();
 

src/main/flight/pid.c

@@ -460,7 +460,7 @@ STATIC_UNIT_TESTED FAST_CODE_NOINLINE float pidLevel(int axis, const pidProfile_
     return currentPidSetpoint;
 }
 
-static void handleCrashRecovery(
+static FAST_CODE_NOINLINE void handleCrashRecovery(
     const pidCrashRecovery_e crash_recovery, const rollAndPitchTrims_t *angleTrim,
     const int axis, const timeUs_t currentTimeUs, const float gyroRate, float *currentPidSetpoint, float *errorRate)
 {
@@ -502,7 +502,7 @@ static void handleCrashRecovery(
     }
 }
 
-static void detectAndSetCrashRecovery(
+static FAST_CODE_NOINLINE void detectAndSetCrashRecovery(
     const pidCrashRecovery_e crash_recovery, const int axis,
     const timeUs_t currentTimeUs, const float delta, const float errorRate)
 {

src/main/sensors/gyro.c

@@ -133,12 +133,12 @@ void pgResetFn_gyroConfig(gyroConfig_t *gyroConfig)
     gyroConfig->simplified_gyro_filter_multiplier = SIMPLIFIED_TUNING_DEFAULT;
 }
 
-FAST_CODE bool isGyroSensorCalibrationComplete(const gyroSensor_t *gyroSensor)
+bool isGyroSensorCalibrationComplete(const gyroSensor_t *gyroSensor)
 {
     return gyroSensor->calibration.cyclesRemaining == 0;
 }
 
-FAST_CODE bool gyroIsCalibrationComplete(void)
+bool gyroIsCalibrationComplete(void)
 {
     switch (gyro.gyroToUse) {
         default:
@@ -203,7 +203,7 @@ bool isFirstArmingGyroCalibrationRunning(void)
     return firstArmingCalibrationWasStarted && !gyroIsCalibrationComplete();
 }
 
-STATIC_UNIT_TESTED void performGyroCalibration(gyroSensor_t *gyroSensor, uint8_t gyroMovementCalibrationThreshold)
+STATIC_UNIT_TESTED NOINLINE void performGyroCalibration(gyroSensor_t *gyroSensor, uint8_t gyroMovementCalibrationThreshold)
 {
     for (int axis = 0; axis < XYZ_AXIS_COUNT; axis++) {
         // Reset g[axis] at start of calibration