【嵌入式开源库】timeslice的使用，完全解耦的时间片轮询框架构

完全解耦的时间片轮询框架构

简介
项目代码
- timeslice.h
- timeslice.c
- list.h
- list.c
创建工程
移植代码
实验
函数说明
结尾

简介

timeslice是一个时间片轮询框架，他是一个完全解耦的时间片轮询框架，他的使用非常方便，该项目一共有四个文件分别是tieslice的头文件和源文件以及list的头文件和源文件，tieslice是负责轮询任务，list是一个双向链表负责任务的管理，在Linux内核中使用非常广泛也很经典，该框架是参考rtt实时操作系统的侵入式链表实现的，本章文章是将该框架移植到stm32单片机上实验，使用也非常容易，单片机只需要启用一个定时器作为时钟即可；

本章使用环境：

stm32f407vet6

代码工程使用cubemx创建

项目代码

该项目的代码是我在微信公众号上看到的一个文章，代码并没有上传在github上，这里直接贴上源代码；

timeslice.h

c 复制代码

#ifndef _TIMESLICE_H
#define _TIMESLICE_H

#include "list.h"

typedef enum {
    TASK_STOP,
    TASK_RUN
} IsTaskRun;

typedef struct timesilce
{
    unsigned int id;
    void (*task_hdl)(void);
    IsTaskRun is_run;
    unsigned int timer;
    unsigned int timeslice_len;
    ListObj timeslice_task_list;
} TimesilceTaskObj;

void timeslice_exec(void);
void timeslice_tick(void);
void timeslice_task_init(TimesilceTaskObj* obj, void (*task_hdl)(void), unsigned int id, unsigned int timeslice_len);
void timeslice_task_add(TimesilceTaskObj* obj);
void timeslice_task_del(TimesilceTaskObj* obj);
unsigned int timeslice_get_task_timeslice_len(TimesilceTaskObj* obj);
unsigned int timeslice_get_task_num(void);
unsigned char timeslice_task_isexist(TimesilceTaskObj* obj);

#endif

timeslice.c

c 复制代码

#include "timeslice.h"

static LIST_HEAD(timeslice_task_list);

void timeslice_exec()
{
    ListObj* node;
    TimesilceTaskObj* task;

    list_for_each(node, &timeslice_task_list)
    {

        task = list_entry(node, TimesilceTaskObj, timeslice_task_list);
        if (task->is_run == TASK_RUN)
        {
            task->task_hdl();
            task->is_run = TASK_STOP;
        }
    }
}

void timeslice_tick()
{
    ListObj* node;
    TimesilceTaskObj* task;

    list_for_each(node, &timeslice_task_list)
    {
        task = list_entry(node, TimesilceTaskObj, timeslice_task_list);
        if (task->timer != 0)
        {
            task->timer--;
            if (task->timer == 0)
            {
                task->is_run = TASK_RUN;
                task->timer = task->timeslice_len;
            }
        }
    }
}

unsigned int timeslice_get_task_num()
{
    return list_len(&timeslice_task_list);
}

void timeslice_task_init(TimesilceTaskObj* obj, void (*task_hdl)(void), unsigned int id, unsigned int timeslice_len)
{
    obj->id = id;
    obj->is_run = TASK_STOP;
    obj->task_hdl = task_hdl;
    obj->timer = timeslice_len;
    obj->timeslice_len = timeslice_len;
}

void timeslice_task_add(TimesilceTaskObj* obj)
{
    list_insert_before(&timeslice_task_list, &obj->timeslice_task_list);
}

void timeslice_task_del(TimesilceTaskObj* obj)
{
    if (timeslice_task_isexist(obj))
        list_remove(&obj->timeslice_task_list);
    else
        return;
}


unsigned char timeslice_task_isexist(TimesilceTaskObj* obj)
{
    unsigned char isexist = 0;
    ListObj* node;
    TimesilceTaskObj* task;

    list_for_each(node, &timeslice_task_list)
    {
        task = list_entry(node, TimesilceTaskObj, timeslice_task_list);
        if (obj->id == task->id)
            isexist = 1;
    }

    return isexist;
}

unsigned int timeslice_get_task_timeslice_len(TimesilceTaskObj* obj)
{
    return obj->timeslice_len;
}

list.h

c 复制代码

#ifndef _LIST_H
#define _LIST_H

#define offset_of(type, member)             (unsigned long) &((type*)0)->member
#define container_of(ptr, type, member)     ((type *)((char *)(ptr) - offset_of(type, member)))

typedef struct list_structure
{
    struct list_structure* next;
    struct list_structure* prev;
} ListObj;

#define LIST_HEAD_INIT(name)    {&(name), &(name)}
#define LIST_HEAD(name)         ListObj name = LIST_HEAD_INIT(name)

void list_init(ListObj* list);
void list_insert_after(ListObj* list, ListObj* node);
void list_insert_before(ListObj* list, ListObj* node);
void list_remove(ListObj* node);
int list_isempty(const ListObj* list);
unsigned int list_len(const ListObj* list);

#define list_entry(node, type, member) \
    container_of(node, type, member)

#define list_for_each(pos, head) \
    for (pos = (head)->next; pos != (head); pos = pos->next)

#define list_for_each_safe(pos, n, head) \
  for (pos = (head)->next, n = pos->next; pos != (head); \
    pos = n, n = pos->next)

#endif

list.c

c 复制代码

#include "list.h"

void list_init(ListObj* list)
{
    list->next = list->prev = list;
}

void list_insert_after(ListObj* list, ListObj* node)
{
    list->next->prev = node;
    node->next = list->next;

    list->next = node;
    node->prev = list;
}

void list_insert_before(ListObj* list, ListObj* node)
{
    list->prev->next = node;
    node->prev = list->prev;

    list->prev = node;
    node->next = list;
}

void list_remove(ListObj* node)
{
    node->next->prev = node->prev;
    node->prev->next = node->next;

    node->next = node->prev = node;
}

int list_isempty(const ListObj* list)
{
    return list->next == list;
}

unsigned int list_len(const ListObj* list)
{
    unsigned int len = 0;
    const ListObj* p = list;
    while (p->next != list)
    {
        p = p->next;
        len++;
    }

    return len;
}

创建工程

配置高速时钟和低速时钟为外部晶振提供

配置调试模式为sw调试模式

配置时钟频率
配置led，这里我的板子是这三个io接入的是led

配置一个10ms的定时器（1000000hz / 1000ms == 1ms = 1khz 就得到10ms需要计数10000重载）记得打开中断

配置工程并生成，工程名设置，单独生成.c.h文件拷贝库文件

下面开始代码的移植工作；

移植代码

首先我们需要将该开源项目的代码添加到工程中
在定时器中断服务函数中添加timeslice轮询函数

c 复制代码

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
	if(htim->Instance == TIM3)
	{
		timeslice_tick();
	}
}

然后我们需要在main函数中启动定时器并在while1中调用exec函数调度时间片

c 复制代码

 HAL_TIM_Base_Start_IT(&htim3);
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
	  
	  timeslice_exec();
  }

到这里我们的移植工作就做完了，该项目的解耦效果真的非常好，移植相当简单，然后我们创建几个任务实验一下效果；

实验

c 复制代码

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2023 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "tim.h"
#include "gpio.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "timeslice.h"
/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

/* USER CODE BEGIN PV */
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
	if(htim->Instance == TIM3)
	{
		timeslice_tick();
	}
}


// 创建3个任务对象
TimesilceTaskObj task_1, task_2, task_3;

// 具体的任务函数
void task1_hdl()
{
    HAL_GPIO_TogglePin(GPIOE, GPIO_PIN_13);
}

void task2_hdl()
{
    HAL_GPIO_TogglePin(GPIOE, GPIO_PIN_14 );
}

void task3_hdl()
{
    HAL_GPIO_TogglePin(GPIOE, GPIO_PIN_15);
}

// 初始化任务对象，并且将任务添加到时间片轮询调度中
void task_init()
{
    timeslice_task_init(&task_1, task1_hdl, 1, 1);
    timeslice_task_init(&task_2, task2_hdl, 2, 1);
    timeslice_task_init(&task_3, task3_hdl, 3, 1);

    timeslice_task_add(&task_1);
    timeslice_task_add(&task_2);
    timeslice_task_add(&task_3);
}
/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_TIM3_Init();
  /* USER CODE BEGIN 2 */
  HAL_TIM_Base_Start_IT(&htim3);
	task_init();
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
	  
	  timeslice_exec();
  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Configure the main internal regulator output voltage
  */
  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 25;
  RCC_OscInitStruct.PLL.PLLN = 336;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 4;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
  {
    Error_Handler();
  }
}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  __disable_irq();
  while (1)
  {
  }
  /* USER CODE END Error_Handler_Debug */
}

#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

核心部分

c 复制代码

// 创建3个任务对象
TimesilceTaskObj task_1, task_2, task_3;

// 具体的任务函数
void task1_hdl()
{
    HAL_GPIO_TogglePin(GPIOE, GPIO_PIN_13);
}

void task2_hdl()
{
    HAL_GPIO_TogglePin(GPIOE, GPIO_PIN_14 );
}

void task3_hdl()
{
    HAL_GPIO_TogglePin(GPIOE, GPIO_PIN_15);
}

// 初始化任务对象，并且将任务添加到时间片轮询调度中
void task_init()
{
    timeslice_task_init(&task_1, task1_hdl, 1, 1);
    timeslice_task_init(&task_2, task2_hdl, 2, 2);
    timeslice_task_init(&task_3, task3_hdl, 3, 3);

    timeslice_task_add(&task_1);
    timeslice_task_add(&task_2);
    timeslice_task_add(&task_3);
}

需要注意的是必须要有一个任务是需要在exec前创建，这样才能保证运行，其他的任务可以在这个任务中再创建，上面的实验是实现三个任务，三个任务分别为一个中断触发一次，第二个任务是每隔两个中断触发一次，第三个任务是每隔三个中断触发一次任务；

函数说明

timeslice_task_init

初始化任务函数

c 复制代码

void timeslice_task_init(TimesilceTaskObj* obj, void (*task_hdl)(void), unsigned int id, unsigned int timeslice_len)
{
    obj->id = id;
    obj->is_run = TASK_STOP;
    obj->task_hdl = task_hdl;
    obj->timer = timeslice_len;
    obj->timeslice_len = timeslice_len;
}

在这个函数中将任务结构体参数初始化，id类似于任务名称用于区分任务，is_run是一个标志位用于判断该任务在该次中断是否需要执行，task_hd1表示函数指针也就是我们的任务函数，timer表示每多少次中断触发一次计数，timeslice_len 表示没多少次中断触发一次计数初始值，在timeslice_tick中当timer的值减到0任务将触发并会重新复位timer的值为 timeslice_len ；

timeslice_task_add

添加任务到双向链表中

c 复制代码

void timeslice_task_add(TimesilceTaskObj* obj)
{
    list_insert_before(&timeslice_task_list, &obj->timeslice_task_list);
}

void list_insert_before(ListObj* list, ListObj* node)
{
    list->prev->next = node;
    node->prev = list->prev;

    list->prev = node;
    node->next = list;
}

该链表（timeslice_task_list）在timeslice_tick中会轮询进行遍历

timeslice_tak_del

删除正在运行的任务链表

c 复制代码

void timeslice_task_del(TimesilceTaskObj* obj)
{
    if (timeslice_task_isexist(obj))
        list_remove(&obj->timeslice_task_list);
    else
        return;
}

在该函数中会通过timeslice_task_isexist函数去判断链表中是否存在该任务的id，如果存在将返回退出允许，这里涉及到一个Linux中的函数list_entry->container_of,该函数是通过结构体的某个变量获取整个结构体的指针位置，有兴趣可以去学习一下该项目代码的实现；

timeslice_get_task_num

获取当前任务数量，也就是链表的长度

c 复制代码

unsigned int timeslice_get_task_num()
{
    return list_len(&timeslice_task_list);
}

unsigned int list_len(const ListObj* list)
{
    unsigned int len = 0;
    const ListObj* p = list;
    while (p->next != list)
    {
        p = p->next;
        len++;
    }

    return len;
}

结尾

整体的代码不算复杂但是是值得学习的一个项目，我是凉开水白菜祝各位程序员们节日快乐~ 咱们下文见~