How to realize hierarchical management of application and hardware in embedded projects

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layout  | Embedded hodgepodge

source ：
https://blog.csdn.net/ziqi5543/article/details/101512722

One 、 Preface

With STM32 For example , Open the routines downloaded from the network or purchase the routines from the development board , You will find that there will be stm32f10x.h perhaps stm32f10x_gpio.h, These files strictly belong to the hardware layer , If these files appear in the software layer, they will appear very messy .

Have used Linux Children's shoes must know linux The system cannot directly operate the hardware layer , open linux perhaps rt_thread The code will find that there will be device The source file , you 're right , This is the driver layer .

Two 、 Realization principle

The principle is to put all the hardware operation interfaces on the drive chain list , In the driver layer device Of open、read、write Wait for the operation . Of course, there are drawbacks in doing so , It's driving find You need to traverse the drive linked list , This will increase the code running time .

3、 ... and 、 Code implementation

International practice , Write the header file before writing the code .rt_thread Is a two-way linked list , For simplicity, I only use one-way linked list here . If you are interested, you can study it yourself rt_thread

Header file interface :

Only the following interfaces are implemented this time ,device_open   and device_close The rest of the interfaces can be researched by yourself . In this way, only the following interfaces can be called in the application layer ：

/*
     Driver registration 
*/
int cola_device_register(cola_device_t *dev);
/*
     Drive lookup 
*/
cola_device_t *cola_device_find(const char *name);
/*
     Drive read 
*/
int cola_device_read(cola_device_t *dev,  int pos, void *buffer, int size);
/*
     Drive write 
*/
int cola_device_write(cola_device_t *dev, int pos, const void *buffer, int size);
/*
     drive control 
*/
int cola_device_ctrl(cola_device_t *dev,  int cmd, void *arg);;

The header file cola_device.h：

#ifndef _COLA_DEVICE_H_
#define _COLA_DEVICE_H_
 
 
enum LED_state
{
    LED_OFF,
    LED_ON,
    LED_TOGGLE,
 
};
 
typedef struct cola_device  cola_device_t;
 
struct cola_device_ops
{
    int  (*init)   (cola_device_t *dev);
    int  (*open)   (cola_device_t *dev, int oflag);
    int  (*close)  (cola_device_t *dev);
    int  (*read)   (cola_device_t *dev, int pos, void *buffer, int size);
    int  (*write)  (cola_device_t *dev, int pos, const void *buffer, int size);
    int  (*control)(cola_device_t *dev, int cmd, void *args);
 
};
 
struct cola_device
{
    const char * name;
    struct cola_device_ops *dops;
    struct cola_device *next;
};
 
/*
     Driver registration 
*/
int cola_device_register(cola_device_t *dev);
/*
     Drive lookup 
*/
cola_device_t *cola_device_find(const char *name);
/*
     Drive read 
*/
int cola_device_read(cola_device_t *dev,  int pos, void *buffer, int size);
/*
     Drive write 
*/
int cola_device_write(cola_device_t *dev, int pos, const void *buffer, int size);
/*
     drive control 
*/
int cola_device_ctrl(cola_device_t *dev,  int cmd, void *arg);
 
#endif

Source file cola_device.c：

#include "cola_device.h"
#include <string.h>
#include <stdbool.h>
 
 
struct cola_device *device_list = NULL;
 
/*
     Find out if the task exists 
*/
static bool cola_device_is_exists( cola_device_t *dev )
{
    cola_device_t* cur = device_list;
    while( cur != NULL )
    {
        if( strcmp(cur->name,dev->name)==0)
        {
            return true;
        }
        cur = cur->next;
    }
    return false;
}
 
 
static int device_list_inster(cola_device_t *dev)
{
    cola_device_t *cur = device_list;
    if(NULL == device_list)
    {
        device_list = dev;
        dev->next   = NULL;
    }
    else
    {
        while(NULL != cur->next)
        {
            cur = cur->next;
        }
        cur->next = dev;
        dev->next = NULL;
    }
    return 1;
}
 
/*
     Driver registration 
*/
int cola_device_register(cola_device_t *dev)
{
    if((NULL == dev) || (cola_device_is_exists(dev)))
    {
        return 0;
    }
 
    if((NULL == dev->name) ||  (NULL == dev->dops))
    {
        return 0;
    }
    return device_list_inster(dev);
 
}
/*
     Drive lookup 
*/
cola_device_t *cola_device_find(const char *name)
{
    cola_device_t* cur = device_list;
    while( cur != NULL )
    {
        if( strcmp(cur->name,name)==0)
        {
            return cur;
        }
        cur = cur->next;
    }
    return NULL;
}
/*
     Drive read 
*/
int cola_device_read(cola_device_t *dev,  int pos, void *buffer, int size)
{
    if(dev)
    {
        if(dev->dops->read)
        {
            return dev->dops->read(dev, pos, buffer, size);
        }
    }
    return 0;
}
/*
     Drive write 
*/
int cola_device_write(cola_device_t *dev, int pos, const void *buffer, int size)
{
    if(dev)
    {
        if(dev->dops->write)
        {
            return dev->dops->write(dev, pos, buffer, size);
        }
    }
    return 0;
}
/*
     drive control 
*/
int cola_device_ctrl(cola_device_t *dev,  int cmd, void *arg)
{
    if(dev)
    {
        if(dev->dops->control)
        {
            return dev->dops->control(dev, cmd, arg);
        }
    }
    return 0;
}

Hardware registration method : With LED For example , Initialization interface void led_register(void), You need to call... During initialization .

#include "stm32f0xx.h"
#include "led.h"
#include "cola_device.h"
 
 
#define PORT_GREEN_LED                 GPIOC                   
#define PIN_GREENLED                   GPIO_Pin_13              
 
/* LED bright 、 destroy 、 change  */
#define LED_GREEN_OFF                  (PORT_GREEN_LED->BSRR = PIN_GREENLED)
#define LED_GREEN_ON                   (PORT_GREEN_LED->BRR  = PIN_GREENLED)
#define LED_GREEN_TOGGLE               (PORT_GREEN_LED->ODR ^= PIN_GREENLED)
 
 
static cola_device_t led_dev;
 
static void led_gpio_init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC, ENABLE);
    GPIO_InitStructure.GPIO_Pin = PIN_GREENLED;                            
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;                     
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;                  
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;                     
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;                  
    GPIO_Init(PORT_GREEN_LED, &GPIO_InitStructure);
    LED_GREEN_OFF;
}
 
static int led_ctrl(cola_device_t *dev, int cmd, void *args)
{
    if(LED_TOGGLE == cmd)
    {
        LED_GREEN_TOGGLE;
    }
    else 
    {
        
    }
    return 1;
}
 
 
static struct cola_device_ops ops =
{
    .control = led_ctrl,
};
 
void led_register(void)
{
    led_gpio_init();
    led_dev.dops = &ops;
    led_dev.name = "led";
    cola_device_register(&led_dev);
}

application layer app Code :

#include <string.h>
#include "app.h"
#include "config.h"
#include "cola_device.h"
#include "cola_os.h"
 
static task_t timer_500ms;
static cola_device_t *app_led_dev;
 
//led Every time 500ms The state changes once 
static void timer_500ms_cb(uint32_t event)
{
    cola_device_ctrl(app_led_dev,LED_TOGGLE,0);
}
 
void app_init(void)
{
    app_led_dev = cola_device_find("led");
    assert(app_led_dev);
    cola_timer_create(&timer_500ms,timer_500ms_cb);
    cola_timer_start(&timer_500ms,TIMER_ALWAYS,500);
}

such app.c There is no need to call... In the file led.h Header file ,rtt That's how it works .

Four 、 summary

In this way, the software and hardware can be layered , It's not very easy to use ！

5、 ... and 、 Code download link

https://gitee.com/schuck/cola_os

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