[Time] Review delay

cores/arduino/board.h

@@ -10,6 +10,7 @@
 #include "clock.h"
 #include "core_callback.h"
 #include "digital_io.h"
+#include "dwt.h"
 #include "hw_config.h"
 #include "low_power.h"
 #include "rtc.h"

cores/arduino/stm32/clock.c

@@ -48,7 +48,7 @@ extern "C" {
   * @param  None
   * @retval None
   */
-uint32_t GetCurrentMicro(void)
+uint32_t getCurrentMicros(void)
 {
   /* Ensure COUNTFLAG is reset by reading SysTick control and status register */
   LL_SYSTICK_IsActiveCounterFlag();
@@ -66,7 +66,7 @@ uint32_t GetCurrentMicro(void)
   * @param  None
   * @retval None
   */
-uint32_t GetCurrentMilli(void)
+uint32_t getCurrentMillis(void)
 {
   return HAL_GetTick();
 }
@@ -78,7 +78,7 @@ void noOsSystickHandler()
 
 void osSystickHandler() __attribute__((weak, alias("noOsSystickHandler")));
 /**
-  * @brief  Function called when t he tick interruption falls
+  * @brief  Function called when the tick interruption falls
   * @param  None
   * @retval None
   */

cores/arduino/stm32/clock.h

@@ -58,8 +58,8 @@ typedef enum {
 /* Exported constants --------------------------------------------------------*/
 /* Exported macro ------------------------------------------------------------*/
 /* Exported functions ------------------------------------------------------- */
-uint32_t GetCurrentMilli(void);
-uint32_t GetCurrentMicro(void);
+uint32_t getCurrentMillis(void);
+uint32_t getCurrentMicros(void);
 
 void enableClock(sourceClock_t source);
 #ifdef __cplusplus

cores/arduino/stm32/dwt.c

@@ -0,0 +1,89 @@
+/**
+  ******************************************************************************
+  * @file    dwt.c
+  * @author  Frederic Pillon
+  * @brief   Provide Data Watchpoint and Trace services
+  ******************************************************************************
+  * @attention
+  *
+  * Copyright (c) 2019, STMicroelectronics
+  * All rights reserved.
+  *
+  * This software component is licensed by ST under BSD 3-Clause license,
+  * the "License"; You may not use this file except in compliance with the
+  * License. You may obtain a copy of the License at:
+  *                        opensource.org/licenses/BSD-3-Clause
+  *
+  ******************************************************************************
+  */
+
+#include "dwt.h"
+
+#ifdef DWT_BASE
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+uint32_t dwt_init(void)
+{
+
+  /* Enable use of DWT */
+  if (!(CoreDebug->DEMCR & CoreDebug_DEMCR_TRCENA_Msk)) {
+    CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
+  }
+
+  /* Unlock */
+  dwt_access(true);
+
+  /* Reset the clock cycle counter value */
+  DWT->CYCCNT = 0;
+
+  /* Enable  clock cycle counter */
+  DWT->CTRL |=  DWT_CTRL_CYCCNTENA_Msk;
+
+  /* 3 NO OPERATION instructions */
+  asm volatile(" nop      \n\t"
+               " nop      \n\t"
+               " nop      \n\t");
+
+  /* Check if clock cycle counter has started */
+  return (DWT->CYCCNT) ? 0 : 1;
+}
+
+void dwt_access(bool ena)
+{
+#if (__CORTEX_M == 0x07U)
+  /*
+   * Define DWT LSR mask which is (currentuly) not defined by the CMSIS.
+   * Same as ITM LSR one.
+   */
+#if !defined DWT_LSR_Present_Msk
+#define DWT_LSR_Present_Msk ITM_LSR_Present_Msk
+#endif
+#if !defined DWT_LSR_Access_Msk
+#define DWT_LSR_Access_Msk ITM_LSR_Access_Msk
+#endif
+  uint32_t lsr = DWT->LSR;
+
+  if ((lsr & DWT_LSR_Present_Msk) != 0) {
+    if (ena) {
+      if ((lsr & DWT_LSR_Access_Msk) != 0) { //locked
+        DWT->LAR = 0xC5ACCE55;
+      }
+    } else {
+      if ((lsr & DWT_LSR_Access_Msk) == 0) { //unlocked
+        DWT->LAR = 0;
+      }
+    }
+  }
+#else /* __CORTEX_M */
+  UNUSED(ena);
+#endif /* __CORTEX_M */
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

cores/arduino/stm32/dwt.h

@@ -0,0 +1,61 @@
+/**
+  ******************************************************************************
+  * @file    dwt.h
+  * @author  Frederic Pillon
+  * @brief   Header for dwt.c module
+  ******************************************************************************
+  * @attention
+  *
+  * Copyright (c) 2019, STMicroelectronics
+  * All rights reserved.
+  *
+  * This software component is licensed by ST under BSD 3-Clause license,
+  * the "License"; You may not use this file except in compliance with the
+  * License. You may obtain a copy of the License at:
+  *                        opensource.org/licenses/BSD-3-Clause
+  *
+  ******************************************************************************
+  */
+
+/* Define to prevent recursive inclusion -------------------------------------*/
+#ifndef _DWT_H_
+#define _DWT_H_
+
+#include "stm32_def.h"
+#include <stdbool.h>
+
+#ifdef DWT_BASE
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+uint32_t dwt_init(void);
+void dwt_access(bool ena);
+
+static inline uint32_t dwt_max_sec(void)
+{
+  return (UINT32_MAX / SystemCoreClock);
+};
+
+static inline uint32_t dwt_max_msec(void)
+{
+  return (UINT32_MAX / (SystemCoreClock / 1000));
+};
+
+static inline uint32_t dwt_max_usec(void)
+{
+  return (UINT32_MAX / (SystemCoreClock / 1000000));
+};
+
+static inline uint32_t dwt_getCycles(void)
+{
+  return (DWT->CYCCNT);
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* DWT_BASE */
+#endif /* _DWT_H_ */

cores/arduino/stm32/hw_config.c

@@ -38,6 +38,7 @@
 #include "stm32_def.h"
 #include "hw_config.h"
 #include "usbd_if.h"
+#include "dwt.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -50,15 +51,21 @@ extern "C" {
   */
 void hw_config_init(void)
 {
-  //Initialize the HAL
+  /* Init DWT if present */
+#ifdef DWT_BASE
+  dwt_init();
+#endif
+
+  /* Initialize the HAL */
   HAL_Init();
 
-  // Configure the system clock
+  /* Configure the system clock */
   SystemClock_Config();
 
 #if defined (USBCON) && defined(USBD_USE_CDC)
   USBD_CDC_init();
 #endif
+
 }
 #ifdef __cplusplus
 }

cores/arduino/wiring_time.c

@@ -24,25 +24,24 @@ extern "C" {
 
 uint32_t millis(void)
 {
-  // todo: ensure no interrupts
-  return GetCurrentMilli() ;
+  // ToDo: ensure no interrupts
+  return getCurrentMillis();
 }
 
 // Interrupt-compatible version of micros
 uint32_t micros(void)
 {
-  return GetCurrentMicro();
+  return getCurrentMicros();
 }
 
 void delay(uint32_t ms)
 {
-  if (ms == 0) {
-    return;
+  if (ms != 0) {
+    uint32_t start = getCurrentMillis();
+    do {
+      yield();
+    } while (getCurrentMillis() - start < ms);
   }
-  uint32_t start = GetCurrentMilli();
-  do {
-    yield();
-  } while (GetCurrentMilli() - start < ms);
 }
 
 #ifdef __cplusplus

cores/arduino/wiring_time.h

@@ -21,6 +21,7 @@
 #define _WIRING_TIME_H_
 
 #include "clock.h"
+#include "dwt.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -50,21 +51,27 @@ extern uint32_t micros(void) ;
  * \brief Pauses the program for the amount of time (in miliseconds) specified as parameter.
  * (There are 1000 milliseconds in a second.)
  *
- * \param dwMs the number of milliseconds to pause (uint32_t)
+ * \param ms the number of milliseconds to pause (uint32_t)
  */
-extern void delay(uint32_t dwMs) ;
+extern void delay(uint32_t ms) ;
 
 /**
  * \brief Pauses the program for the amount of time (in microseconds) specified as parameter.
  *
- * \param dwUs the number of microseconds to pause (uint32_t)
+ * \param us the number of microseconds to pause (uint32_t)
  */
 static inline void delayMicroseconds(uint32_t) __attribute__((always_inline, unused));
-static inline void delayMicroseconds(uint32_t usec)
+static inline void delayMicroseconds(uint32_t us)
 {
-  uint32_t start = GetCurrentMicro();
+#if defined(DWT_BASE) && !defined(DWT_DELAY_DISABLED)
+  int32_t start  = dwt_getCycles();
+  int32_t cycles = us * (SystemCoreClock / 1000000);
 
-  while ((start + usec) > GetCurrentMicro());
+  while ((int32_t)dwt_getCycles() - start < cycles);
+#else
+  uint32_t start = getCurrentMicros();
+  while (getCurrentMicros() - start < us);
+#endif
 }
 
 #ifdef __cplusplus