faster uniform adc cleanup (#3334)

* dead fast tps

* oooooh map avg on hh7

* adc v4 fast support

* new fast API

* hardware.cpp

* adc v2

* warning

* guard

* no check required

* stub cypress/kinetis

* kinetis and cypress stubs

* cleanup

* h7 adc speed

* adc skip

* configurable oversample

firmware/config/boards/hellen/hellen81/board.mk

@@ -37,12 +37,7 @@ DDEFS += -DEFI_LOGIC_ANALYZER=FALSE
 
 TRIGGER_USE_ADC = yes
 
-# we need fast ADC for software trigger detector
+DDEFS += -DFAST_ADC_SKIP=3 -DH7_ADC_SPEED=20000 -DH7_ADC_OVERSAMPLE=2
-#DDEFS += -DEFI_OVERRIDE_FAST_ADC_FOR_STM32H7=TRUE -DADC_FAST_DEVICE=ADCD1 -DADC_SLOW_DEVICE=ADCD3 -DSTM32_ADC_USE_ADC3=TRUE
-#DDEFS += -DADC_SLOW_DEVICE=ADCD3 -DSTM32_ADC_USE_ADC3=TRUE
-
-DDEFS += -DEFI_OVERRIDE_FAST_ADC_FOR_STM32H7=TRUE -DADC_FAST_DEVICE=ADCD1 -DEFI_USE_ONLY_FAST_ADC=TRUE -DEFI_FASTER_UNIFORM_ADC=TRUE -DADC_MAX_CHANNELS_COUNT=16 -DADC_BUF_DEPTH_FAST=1 -DADC_BUF_NUM_AVG=1
-#DDEFS += -DADC_SLOW_DEVICE=ADCD1
 
 # We are running on Hellen-One hardware!
 DDEFS += -DHW_HELLEN=1

firmware/hw_layer/hardware.cpp

@@ -148,53 +148,32 @@ static FastAdcToken triggerSampleIndex;
 
 extern AdcDevice fastAdc;
 
-#if EFI_FASTER_UNIFORM_ADC
+#ifdef FAST_ADC_SKIP
-static int adcCallbackCounter = 0;
+// No reason to enable if N = 1
-static volatile int averagedSamples[ADC_MAX_CHANNELS_COUNT];
+static_assert(FAST_ADC_SKIP > 1);
-static adcsample_t avgBuf[ADC_MAX_CHANNELS_COUNT];
+static size_t fastAdcSkipCount = 0;
+#endif // FAST_ADC_SKIP
 
-void onFastAdcCompleteInternal(adcsample_t* samples);
+/**
+ * This method is not in the adc* lower-level file because it is more business logic then hardware.
+ */
+void onFastAdcComplete(adcsample_t*) {
+	ScopePerf perf(PE::AdcCallbackFast);
 
-void onFastAdcComplete(adcsample_t* samples) {
 #if HAL_TRIGGER_USE_ADC
 	// we need to call this ASAP, because trigger processing is time-critical
 	triggerAdcCallback(getFastAdc(triggerSampleIndex));
 #endif /* HAL_TRIGGER_USE_ADC */
 
-	// store the values for averaging
+#ifdef FAST_ADC_SKIP
-	for (int i = fastAdc.size() - 1; i >= 0; i--) {
+	// If we run the fast ADC _very_ fast for triggerAdcCallback's benefit, we may want to
-		averagedSamples[i] += samples[i];
+	// skip most of the samples for the rest of the callback.
+	if (fastAdcSkipCount++ == FAST_ADC_SKIP) {
+		fastAdcSkipCount = 0;
+	} else {
+		return;
 	}
-
-	// if it's time to process the data
-	if (++adcCallbackCounter >= ADC_BUF_NUM_AVG) {
-		// get an average
-		for (int i = fastAdc.size() - 1; i >= 0; i--) {
-			avgBuf[i] = (adcsample_t)(averagedSamples[i] / ADC_BUF_NUM_AVG);	// todo: rounding?
-		}
-
-		// call the real callback (see below)
-		onFastAdcCompleteInternal(samples);
-
-		// reset the avg buffer & counter
-		for (int i = fastAdc.size() - 1; i >= 0; i--) {
-			averagedSamples[i] = 0;
-		}
-		adcCallbackCounter = 0;
-	}
-}
-
-#endif /* EFI_FASTER_UNIFORM_ADC */
-
-/**
- * This method is not in the adc* lower-level file because it is more business logic then hardware.
- */
-#if EFI_FASTER_UNIFORM_ADC
-void onFastAdcCompleteInternal(adcsample_t*) {
-#else
-void onFastAdcComplete(adcsample_t*) {
 #endif
-	ScopePerf perf(PE::AdcCallbackFast);
 
 	/**
 	 * this callback is executed 10 000 times a second, it needs to be as fast as possible
@@ -237,13 +216,6 @@ static void adcConfigListener(Engine *engine) {
 }
 
 static void turnOnHardware(DECLARE_ENGINE_PARAMETER_SIGNATURE) {
-#if EFI_FASTER_UNIFORM_ADC
-	for (int i = 0; i < ADC_MAX_CHANNELS_COUNT; i++) {
-		averagedSamples[i] = 0;
-	}
-	adcCallbackCounter = 0;
-#endif /* EFI_FASTER_UNIFORM_ADC */
-
 #if EFI_PROD_CODE && EFI_SHAFT_POSITION_INPUT
 	turnOnTriggerInputPins(PASS_ENGINE_PARAMETER_SIGNATURE);
 #endif /* EFI_SHAFT_POSITION_INPUT */

firmware/hw_layer/ports/stm32/stm32_adc_v4.cpp

@@ -10,6 +10,29 @@
 #include "mpu_util.h"
 #include "map_averaging.h"
 
+#ifndef H7_ADC_SPEED
+#define H7_ADC_SPEED (10000)
+#endif
+
+#ifndef H7_ADC_OVERSAMPLE
+#define H7_ADC_OVERSAMPLE (4)
+#endif
+
+static_assert((H7_ADC_OVERSAMPLE & (H7_ADC_OVERSAMPLE - 1)) == 0, "H7_ADC_OVERSAMPLE must be a power of 2");
+
+constexpr size_t log2_int(size_t x) {
+	size_t result = 0;
+	while (x >>= 1) result++;
+	return result;
+}
+
+// poor man's unit test
+static_assert(log2_int(4) == 2);
+static_assert(log2_int(16) == 4);
+
+// Shift the result by log2(N) bits to divide by N
+static constexpr int H7_ADC_SHIFT_BITS = log2_int(H7_ADC_OVERSAMPLE);
+
 void portInitAdc() {
 	// Init slow ADC
 	adcStart(&ADCD1, NULL);
@@ -50,8 +73,8 @@ static constexpr ADCConversionGroup convGroupSlow = {
 	.end_cb				= adc_callback,
 	.error_cb			= nullptr,
 	.cfgr				= ADC_CFGR_EXTEN_0 | (4 << ADC_CFGR_EXTSEL_Pos),	// External trigger ch4, rising edge: TIM3 TRGO
-	.cfgr2				= 	3 << ADC_CFGR2_OVSR_Pos |	// Oversample by 4x (register contains N-1)
+	.cfgr2				= 	(H7_ADC_OVERSAMPLE - 1) << ADC_CFGR2_OVSR_Pos |	// Oversample by Nx (register contains N-1)
-							2 << ADC_CFGR2_OVSS_Pos |	// shift the result right 2 bits to make a 16 bit result out of the 18 bit internal sum (4x oversampled)
+							H7_ADC_SHIFT_BITS << ADC_CFGR2_OVSS_Pos |		// shift the result right log2(N) bits to make a 16 bit result out of the internal oversample sum
 							ADC_CFGR2_ROVSE,			// Enable oversampling
 	.ccr				= 0,
 	.pcsel				= 0xFFFFFFFF, // enable analog switches on all channels
@@ -119,8 +142,8 @@ bool readSlowAnalogInputs(adcsample_t* convertedSamples) {
 		adcStartConversionI(&ADCD1, &convGroupSlow, convertedSamples, 1);
 	}
 
-	constexpr uint32_t samplingRate = 10000;
+	constexpr uint32_t samplingRate = H7_ADC_SPEED;
-	constexpr uint32_t timerCountFrequency = samplingRate * 100;
+	constexpr uint32_t timerCountFrequency = samplingRate * 10;
 	constexpr uint32_t timerPeriod = timerCountFrequency / samplingRate;
 
 	static constexpr GPTConfig gptCfg = {