File content as of revision 174:b96e65c34a4d:

/* mbed Microcontroller Library
 * Copyright (c) 2006-2016 ARM Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "hal_tick.h"

// A 32-bit timer is used
#if !TIM_MST_16BIT

#define DEBUG_TICK 0 // Set to 1 to toggle a pin (see below which pin) at each tick

extern TIM_HandleTypeDef TimMasterHandle;

extern void HAL_IncTick(void);

volatile uint32_t PreviousVal = 0;

void us_ticker_irq_handler(void);

void timer_irq_handler(void)
{
    // Channel 1 for mbed timeout
    if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC1) == SET) {
        if (__HAL_TIM_GET_IT_SOURCE(&TimMasterHandle, TIM_IT_CC1) == SET) {
            __HAL_TIM_CLEAR_IT(&TimMasterHandle, TIM_IT_CC1);
            us_ticker_irq_handler();
        }
    }

    // Channel 2 for HAL tick
    if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC2) == SET) {
        if (__HAL_TIM_GET_IT_SOURCE(&TimMasterHandle, TIM_IT_CC2) == SET) {
            __HAL_TIM_CLEAR_IT(&TimMasterHandle, TIM_IT_CC2);
            uint32_t val = __HAL_TIM_GetCounter(&TimMasterHandle);
            if ((val - PreviousVal) >= HAL_TICK_DELAY) {
                // Increment HAL variable
                HAL_IncTick();
                // Prepare next interrupt
                __HAL_TIM_SET_COMPARE(&TimMasterHandle, TIM_CHANNEL_2, val + HAL_TICK_DELAY);
                PreviousVal = val;
#if DEBUG_TICK > 0
                HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_6);
#endif
            }
        }
    }
}

// Reconfigure the HAL tick using a standard timer instead of systick.
HAL_StatusTypeDef HAL_InitTick(uint32_t TickPriority)
{
    RCC_ClkInitTypeDef RCC_ClkInitStruct;
    uint32_t PclkFreq;

    // Get clock configuration
    // Note: PclkFreq contains here the Latency (not used after)
    HAL_RCC_GetClockConfig(&RCC_ClkInitStruct, &PclkFreq);

    // Get timer clock value
#if TIM_MST_PCLK == 1
    PclkFreq = HAL_RCC_GetPCLK1Freq();
#else
    PclkFreq = HAL_RCC_GetPCLK2Freq();
#endif

    // Enable timer clock
    TIM_MST_RCC;

    // Reset timer
    TIM_MST_RESET_ON;
    TIM_MST_RESET_OFF;

    // Configure time base
    TimMasterHandle.Instance = TIM_MST;
    TimMasterHandle.Init.Period          = 0xFFFFFFFF;

    // TIMxCLK = PCLKx when the APB prescaler = 1 else TIMxCLK = 2 * PCLKx
#if TIM_MST_PCLK == 1
    if (RCC_ClkInitStruct.APB1CLKDivider == RCC_HCLK_DIV1) {
#else
    if (RCC_ClkInitStruct.APB2CLKDivider == RCC_HCLK_DIV1) {
#endif
        TimMasterHandle.Init.Prescaler   = (uint16_t)((PclkFreq) / 1000000) - 1; // 1 us tick
    } else {
        TimMasterHandle.Init.Prescaler   = (uint16_t)((PclkFreq * 2) / 1000000) - 1; // 1 us tick
    }

    TimMasterHandle.Init.ClockDivision     = 0;
    TimMasterHandle.Init.CounterMode       = TIM_COUNTERMODE_UP;
#if !TARGET_STM32L1
    TimMasterHandle.Init.RepetitionCounter = 0;
#endif
#ifdef TIM_AUTORELOAD_PRELOAD_DISABLE
    TimMasterHandle.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
#endif
    HAL_TIM_OC_Init(&TimMasterHandle);

    NVIC_SetVector(TIM_MST_IRQ, (uint32_t)timer_irq_handler);
    NVIC_EnableIRQ(TIM_MST_IRQ);

    // Channel 1 for mbed timeout
    HAL_TIM_OC_Start(&TimMasterHandle, TIM_CHANNEL_1);

    // Channel 2 for HAL tick
    HAL_TIM_OC_Start(&TimMasterHandle, TIM_CHANNEL_2);
    PreviousVal = __HAL_TIM_GetCounter(&TimMasterHandle);
    __HAL_TIM_SET_COMPARE(&TimMasterHandle, TIM_CHANNEL_2, PreviousVal + HAL_TICK_DELAY);
    __HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_CC2);

#ifndef NDEBUG
#ifdef TIM_MST_DBGMCU_FREEZE
    // Freeze timer on stop/breakpoint
    TIM_MST_DBGMCU_FREEZE;
#endif
#endif

#if DEBUG_TICK > 0
    __HAL_RCC_GPIOB_CLK_ENABLE();
    GPIO_InitTypeDef GPIO_InitStruct;
    GPIO_InitStruct.Pin = GPIO_PIN_6;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FAST;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
#endif

    return HAL_OK;
}

/* NOTE: must be called with interrupts disabled! */
void HAL_SuspendTick(void)
{
    __HAL_TIM_DISABLE_IT(&TimMasterHandle, TIM_IT_CC2);
}

/* NOTE: must be called with interrupts disabled! */
void HAL_ResumeTick(void)
{
    __HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_CC2);
}

#endif // !TIM_MST_16BIT