Add DMA support to HAL and WPILibC (#2080)

wpilibc/src/main/native/include/frc/AnalogInput.h

@@ -19,6 +19,8 @@
 namespace frc {
 
 class SendableBuilder;
+class DMA;
+class DMASample;
 
 /**
  * Analog input class.
@@ -38,6 +40,8 @@ class AnalogInput : public ErrorBase,
                     public SendableHelper<AnalogInput> {
   friend class AnalogTrigger;
   friend class AnalogGyro;
+  friend class DMA;
+  friend class DMASample;
 
  public:
   static constexpr int kAccumulatorModuleNumber = 1;

wpilibc/src/main/native/include/frc/Counter.h

@@ -21,6 +21,8 @@ namespace frc {
 
 class DigitalGlitchFilter;
 class SendableBuilder;
+class DMA;
+class DMASample;
 
 /**
  * Class for counting the number of ticks on a digital input channel.
@@ -36,6 +38,9 @@ class Counter : public ErrorBase,
                 public CounterBase,
                 public Sendable,
                 public SendableHelper<Counter> {
+  friend class DMA;
+  friend class DMASample;
+
  public:
   enum Mode {
     kTwoPulse = 0,

wpilibc/src/main/native/include/frc/DMA.h

@@ -0,0 +1,57 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <hal/Types.h>
+
+#include "frc/ErrorBase.h"
+
+namespace frc {
+class Encoder;
+class Counter;
+class DigitalSource;
+class DutyCycle;
+class AnalogInput;
+class DMASample;
+
+class DMA : public ErrorBase {
+  friend class DMASample;
+
+ public:
+  DMA();
+  ~DMA() override;
+
+  DMA& operator=(DMA&& other) = default;
+  DMA(DMA&& other) = default;
+
+  void SetPause(bool pause);
+  void SetRate(int cycles);
+
+  void AddEncoder(const Encoder* encoder);
+  void AddEncoderPeriod(const Encoder* encoder);
+
+  void AddCounter(const Counter* counter);
+  void AddCounterPeriod(const Counter* counter);
+
+  void AddDigitalSource(const DigitalSource* digitalSource);
+
+  void AddDutyCycle(const DutyCycle* digitalSource);
+
+  void AddAnalogInput(const AnalogInput* analogInput);
+  void AddAveragedAnalogInput(const AnalogInput* analogInput);
+  void AddAnalogAccumulator(const AnalogInput* analogInput);
+
+  void SetExternalTrigger(DigitalSource* source, bool rising, bool falling);
+
+  void StartDMA(int queueDepth);
+  void StopDMA();
+
+ private:
+  hal::Handle<HAL_DMAHandle> dmaHandle;
+};
+}  // namespace frc

wpilibc/src/main/native/include/frc/DMASample.h

@@ -0,0 +1,108 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <hal/AnalogInput.h>
+#include <hal/DMA.h>
+#include <units/units.h>
+
+#include "frc/AnalogInput.h"
+#include "frc/Counter.h"
+#include "frc/DMA.h"
+#include "frc/DutyCycle.h"
+#include "frc/Encoder.h"
+
+namespace frc {
+class DMASample : public HAL_DMASample {
+ public:
+  HAL_DMAReadStatus Update(const DMA* dma, units::second_t timeout,
+                           int32_t* remaining, int32_t* status) {
+    units::millisecond_t ms = timeout;
+    auto timeoutMs = ms.to<int32_t>();
+    return HAL_ReadDMA(dma->dmaHandle, this, timeoutMs, remaining, status);
+  }
+
+  uint64_t GetTime() const { return timeStamp; }
+
+  units::second_t GetTimeStamp() const {
+    return units::second_t{static_cast<double>(GetTime()) * 1.0e-6};
+  }
+
+  int32_t GetEncoderRaw(const Encoder* encoder, int32_t* status) const {
+    return HAL_GetDMASampleEncoderRaw(this, encoder->m_encoder, status);
+  }
+
+  double GetEncoderDistance(const Encoder* encoder, int32_t* status) const {
+    double val = GetEncoderRaw(encoder, status);
+    val *= encoder->DecodingScaleFactor();
+    val *= encoder->GetDistancePerPulse();
+    return val;
+  }
+
+  int32_t GetEncoderPeriodRaw(const Encoder* encoder, int32_t* status) const {
+    return HAL_GetDMASampleEncoderPeriodRaw(this, encoder->m_encoder, status);
+  }
+
+  int32_t GetCounter(const Counter* counter, int32_t* status) const {
+    return HAL_GetDMASampleCounter(this, counter->m_counter, status);
+  }
+
+  int32_t GetCounterPeriod(const Counter* counter, int32_t* status) const {
+    return HAL_GetDMASampleCounterPeriod(this, counter->m_counter, status);
+  }
+
+  bool GetDigitalSource(const DigitalSource* digitalSource,
+                        int32_t* status) const {
+    return HAL_GetDMASampleDigitalSource(
+        this, digitalSource->GetPortHandleForRouting(), status);
+  }
+
+  int32_t GetAnalogInputRaw(const AnalogInput* analogInput,
+                            int32_t* status) const {
+    return HAL_GetDMASampleAnalogInputRaw(this, analogInput->m_port, status);
+  }
+
+  double GetAnalogInputVoltage(const AnalogInput* analogInput,
+                               int32_t* status) {
+    return HAL_GetAnalogValueToVolts(
+        analogInput->m_port, GetAnalogInputRaw(analogInput, status), status);
+  }
+
+  int32_t GetAveragedAnalogInputRaw(const AnalogInput* analogInput,
+                                    int32_t* status) const {
+    return HAL_GetDMASampleAveragedAnalogInputRaw(this, analogInput->m_port,
+                                                  status);
+  }
+
+  double GetAveragedAnalogInputVoltage(const AnalogInput* analogInput,
+                                       int32_t* status) {
+    return HAL_GetAnalogValueToVolts(
+        analogInput->m_port, GetAveragedAnalogInputRaw(analogInput, status),
+        status);
+  }
+
+  void GetAnalogAccumulator(const AnalogInput* analogInput, int64_t* count,
+                            int64_t* value, int32_t* status) const {
+    return HAL_GetDMASampleAnalogAccumulator(this, analogInput->m_port, count,
+                                             value, status);
+  }
+
+  int32_t GetDutyCycleOutputRaw(const DutyCycle* dutyCycle,
+                                int32_t* status) const {
+    return HAL_GetDMASampleDutyCycleOutputRaw(this, dutyCycle->m_handle,
+                                              status);
+  }
+
+  double GetDutyCycleOutput(const DutyCycle* dutyCycle, int32_t* status) {
+    return GetDutyCycleOutputRaw(dutyCycle, status) /
+           static_cast<double>(dutyCycle->GetOutputScaleFactor());
+  }
+};
+
+static_assert(std::is_pod_v<frc::DMASample>, "DMA Sample MUST Be POD");
+}  // namespace frc

wpilibc/src/main/native/include/frc/DutyCycle.h

@@ -18,6 +18,8 @@
 namespace frc {
 class DigitalSource;
 class AnalogTrigger;
+class DMA;
+class DMASample;
 
 /**
  * Class to read a duty cycle PWM input.
@@ -34,6 +36,8 @@ class DutyCycle : public ErrorBase,
                   public Sendable,
                   public SendableHelper<DutyCycle> {
   friend class AnalogTrigger;
+  friend class DMA;
+  friend class DMASample;
 
  public:
   /**

wpilibc/src/main/native/include/frc/Encoder.h

@@ -23,6 +23,8 @@ namespace frc {
 class DigitalSource;
 class DigitalGlitchFilter;
 class SendableBuilder;
+class DMA;
+class DMASample;
 
 /**
  * Class to read quad encoders.
@@ -44,6 +46,9 @@ class Encoder : public ErrorBase,
                 public PIDSource,
                 public Sendable,
                 public SendableHelper<Encoder> {
+  friend class DMA;
+  friend class DMASample;
+
  public:
   enum IndexingType {
     kResetWhileHigh,