.OpenWrt驱动程序Makefile的分析概述 、驱动程序代码参考、以及测试程序代码参考

#
#
#

include $(TOPDIR)/rules.mk  //一般在 Makefile 的开头
include $(INCLUDE_DIR)/kernel.mk  // 文件对于 软件包为内核时是不可缺少

PKG_NAME:=mydrv  // 表示软件包名称，将在 menuconfig 和 ipkg 可以看到
PKG_RELEASE:=1  //表示软件包版本号

include $(INCLUDE_DIR)/package.mk  //一般在软件包的基本信息完 成后再引入

define KernelPackage/mydrv  //编译包定义，应用程序和内核驱动模块的定义不一样。应用程序软件包使用 Package，內核驱动模 块使用 KernelPackage。
  SUBMENU:=Other modules  //进行分类
  TITLE:=mydrv  //标题
  FILES:=$(PKG_BUILD_DIR)/mydrv.ko  //模块文件
  KCONFIG:=
endef

define KernelPackage/mydrv/description
  This is a mydrv drivers  //描述
endef

MAKE_OPTS:=          //编译之前指定工具和内核arch等
    ARCH="$(LINUX_KARCH)" 
    CROSS_COMPILE="$(TARGET_CROSS)" 
    SUBDIRS="$(PKG_BUILD_DIR)"

define Build/Prepare          //编译前准备工作
    mkdir -p $(PKG_BUILD_DIR)
    $(CP) ./src/* $(PKG_BUILD_DIR)/
endef

define Build/Compile         //进行编译
    $(MAKE) -C "$(LINUX_DIR)" 
    $(MAKE_OPTS) modules
endef



$(eval $(call KernelPackage,mydrv))

以上为驱动程序Makefile代码，驱动程序有两个Makefile，驱动文件夹里有一个（上面）以及src里也有一个Makefile

进入src中Makefile

我们看一下Makefile的内容，非常简单： obj-m += mydrv.o

告诉内核添加的模块目标文件名称为mydrv.o 

当前还包含有驱动程序

mydrv.c

/***************************** 
*
*   驱动程序模板
*   版本：V1
*   使用方法(末行模式下)：
*   :%s/mydrv/"你的驱动名称"/g
*
*******************************/


#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mman.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/raw.h>
#include <linux/tty.h>
#include <linux/capability.h>
#include <linux/ptrace.h>
#include <linux/device.h>
#include <linux/highmem.h>
#include <linux/crash_dump.h>
#include <linux/backing-dev.h>
#include <linux/bootmem.h>
#include <linux/splice.h>
#include <linux/pfn.h>
#include <linux/export.h>
#include <linux/io.h>
#include <linux/aio.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <linux/ioctl.h>


/****************  基本定义 **********************/
//内核空间缓冲区定义
#if 0
    #define KB_MAX_SIZE 20
    #define kbuf[KB_MAX_SIZE];
#endif


//加密函数参数内容： _IOW(IOW_CHAR , IOW_NUMn , IOW_TYPE)
//加密函数用于mydrv_ioctl函数中
//使用举例：ioctl(fd , _IOW('L',0x80,long) , 0x1);
//#define NUMn mydrv , if you need!
#define IOW_CHAR 'L'
#define IOW_TYPE  long
#define IOW_NUM1  0x80


//初始化函数必要资源定义
//用于初始化函数当中
//device number;
    dev_t dev_num;
//struct dev
    struct cdev mydrv_cdev;
//auto "mknode /dev/mydrv c dev_num minor_num"
struct class *mydrv_class = NULL;
struct device *mydrv_device = NULL;


/**************** 结构体 file_operations 成员函数 *****************/
//open
static int mydrv_open(struct inode *inode, struct file *file)
{
    printk("mydrv drive open...
");


    return 0;
}

//close
static int mydrv_close(struct inode *inode , struct file *file)
{
    printk("mydrv drive close...
");


    return 0;
}

//read
static ssize_t mydrv_read(struct file *file, char __user *buffer,
            size_t len, loff_t *pos)
{
    int ret_v = 0;
    printk("mydrv drive read...
");


    return ret_v;
}

//write
static ssize_t mydrv_write( struct file *file , const char __user *buffer,
               size_t len , loff_t *offset )
{
    int ret_v = 0;
    printk("mydrv drive write...
");


    return ret_v;
}

//unlocked_ioctl
static int mydrv_ioctl (struct file *filp , unsigned int cmd , unsigned long arg)
{
    int ret_v = 0;
    printk("mydrv drive ioctl...
");

    switch(cmd)
    {
        //常规：
        //cmd值自行进行修改
        case 0x1:
        {
            if(arg == 0x1) //第二条件；
            {

            }
        }
        break;

        //带密码保护：
        //请在"基本定义"进行必要的定义
        case _IOW(IOW_CHAR,IOW_NUM1,IOW_TYPE):
        {
            if(arg == 0x1) //第二条件
            {
                
            }

        }
        break;

        default:
            break;
    }

    return ret_v;
}


/***************** 结构体： file_operations ************************/
//struct
static const struct file_operations mydrv_fops = {
    .owner   = THIS_MODULE,
    .open     = mydrv_open,
    .release = mydrv_close,    
    .read     = mydrv_read,
    .write   = mydrv_write,
    .unlocked_ioctl    = mydrv_ioctl,
};


/*************  functions: init , exit*******************/
//条件值变量，用于指示资源是否正常使用
unsigned char init_flag = 0;
unsigned char add_code_flag = 0;

//init
static __init int mydrv_init(void)
{
    int ret_v = 0;
    printk("mydrv drive init...
");

    //函数alloc_chrdev_region主要参数说明：
    //参数2： 次设备号
    //参数3： 创建多少个设备
    if( ( ret_v = alloc_chrdev_region(&dev_num,0,1,"mydrv") ) < 0 )
    {
        goto dev_reg_error;
    }
    init_flag = 1; //标示设备创建成功；

    printk("The drive info of mydrv:
major: %d
minor: %d
",
        MAJOR(dev_num),MINOR(dev_num));

    cdev_init(&mydrv_cdev,&mydrv_fops);
    if( (ret_v = cdev_add(&mydrv_cdev,dev_num,1)) != 0 )
    {
        goto cdev_add_error;
    }

    mydrv_class = class_create(THIS_MODULE,"mydrv");
    if( IS_ERR(mydrv_class) )
    {
        goto class_c_error;
    }

    mydrv_device = device_create(mydrv_class,NULL,dev_num,NULL,"mydrv");
    if( IS_ERR(mydrv_device) )
    {
        goto device_c_error;
    }
    printk("auto mknod success!
");

    //------------   请在此添加您的初始化程序  --------------//
       



        //如果需要做错误处理，请：goto mydrv_error;    

     add_code_flag = 1;
    //----------------------  END  ---------------------------// 

    goto init_success;

dev_reg_error:
    printk("alloc_chrdev_region failed
");    
    return ret_v;

cdev_add_error:
    printk("cdev_add failed
");
     unregister_chrdev_region(dev_num, 1);
    init_flag = 0;
    return ret_v;

class_c_error:
    printk("class_create failed
");
    cdev_del(&mydrv_cdev);
     unregister_chrdev_region(dev_num, 1);
    init_flag = 0;
    return PTR_ERR(mydrv_class);

device_c_error:
    printk("device_create failed
");
    cdev_del(&mydrv_cdev);
     unregister_chrdev_region(dev_num, 1);
    class_destroy(mydrv_class);
    init_flag = 0;
    return PTR_ERR(mydrv_device);

//------------------ 请在此添加您的错误处理内容 ----------------//
mydrv_error:
        



    add_code_flag = 0;
    return -1;
//--------------------          END         -------------------//
    
init_success:
    printk("mydrv init success!
");
    return 0;
}

//exit
static __exit void mydrv_exit(void)
{
    printk("mydrv drive exit...
");    

    if(add_code_flag == 1)
     {   
           //----------   请在这里释放您的程序占有的资源   ---------//
        printk("free your resources...
");                   





        printk("free finish
");                       
        //----------------------     END      -------------------//
    }                                

    if(init_flag == 1)
    {
        //释放初始化使用到的资源;
        cdev_del(&mydrv_cdev);
         unregister_chrdev_region(dev_num, 1);
        device_unregister(mydrv_device);
        class_destroy(mydrv_class);
    }
}


/**************** module operations**********************/
//module loading
module_init(mydrv_init);
module_exit(mydrv_exit);

//some infomation
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("from Jafy");
MODULE_DESCRIPTION("mydrv drive");


/*********************  The End ***************************/

测试程序mydir_app

Makefile

##Copyright (C) 2012 OpenWrt.org
#
# This is free software, licensed under the GNU General Public License v2.
# See /LICENSE for more information.
#

include $(TOPDIR)/rules.mk

PKG_NAME:=mydrv_app
PKG_RELEASE:=1

PKG_BUILD_DIR := $(BUILD_DIR)/$(PKG_NAME)

include $(INCLUDE_DIR)/package.mk

define Package/mydrv_app
  SECTION:=utils
  CATEGORY:=Utilities
  TITLE:=Frame buffer device testing tool
  DEPENDS:=+libncurses
endef

define Build/Prepare
    mkdir -p $(PKG_BUILD_DIR)
    $(CP) ./src/* $(PKG_BUILD_DIR)/
endef

define Build/Configure
endef

TARGET_LDFLAGS :=

define Build/Compile
    $(MAKE) -C $(PKG_BUILD_DIR) 
    CC="$(TARGET_CC)" 
    CFLAGS="$(TARGET_CFLAGS) -Wall" 
    LDFLAGS="$(TARGET_LDFLAGS)"
endef

define Package/mydrv_app/install
    $(INSTALL_DIR) $(1)/usr/sbin
    $(INSTALL_BIN) $(PKG_BUILD_DIR)/mydrv_app $(1)/usr/sbin/
endef

$(eval $(call BuildPackage,mydrv_app))

进入src文件夹

Makefile

ll: mydrv_app
OBJS = mydrv_app.o

CC = gcc
CCFLAGS = -Wall -c -o

%.o: %.c
    $(CC) $(CCFLAGS) $@ $< $(LDFLAGS)

fbtest: $(OBJS)
    $(CC) -o $@ $(OBJS) $(LDFLAGS)

clean:
    rm -f rbcfg *.o

测试程序代码

#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>

int main(int argc , char** argv)
{
    int fd;
    int num = 1;

    //打开驱动模块
    fd = open("/dev/mydrv" , O_RDWR|O_NONBLOCK);
    if(fd < 0)
    {
        printf("can't open /dev/mydrv
");
        return -1;
    }

    //函数测试
    write(fd,&num,1);
    read(fd,&num,1);
    ioctl(fd,1,1);
    close(fd);
    
    return 0;
}