Linux 设备驱动之 ioctl 小试牛刀（1）

    ioctl是广大人民群众喜闻乐见的函数之一，这里略作笔记，把以前写的代码整理以下。

 

应用测试程序main.c

#include <stdio.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>#include <linux/ioctl.h>#include "../ioctl_c.h"GPIO_Data_S led_ctl;int main(int argc, char **argv){int testdev = 0;int i = 0;int erro = 0;char buf[10];//打开设备文件testdev = open ("/dev/test",O_RDWR);if(testdev == -1){printf("Cann't open file...../n");exit(0);}while(1){//led_ctl结构赋值led_ctl.port='G';led_ctl.bit=5;led_ctl.value=0;//调用ioctl函数ioctl(testdev,GPIO_IO_SET,&led_ctl);ioctl(testdev,GPIO_IO_WRITE,&led_ctl);ioctl(testdev,GPIO_IO_READ,&led_ctl);sleep(1);led_ctl.port='G';led_ctl.bit=6;led_ctl.value=0;ioctl(testdev,GPIO_IO_SET,&led_ctl);ioctl(testdev,GPIO_IO_WRITE,&led_ctl);ioctl(testdev,GPIO_IO_READ,&led_ctl);sleep(1);}close(testdev);}/*mknod /dev/test c 253 0*/

 

ioctl.h

#ifndef __IOCTL_C_H__#define __IOCTL_C_H__typedef struct GPIO_Data_t{unsigned char port;unsigned int bit;unsigned int value;}GPIO_Data_S;#define GPIO_IOC_MAGIC 12 //Documentation/ioctl-number.txt#define GPIO_IO_SET_GPG _IOW(GPIO_IOC_MAGIC,0,sizeof(GPIO_Data_S))#define GPIO_IO_GET_GPG _IOWR(GPIO_IOC_MAGIC,1,sizeof(GPIO_Data_S))#define GPIO_IO_WRITE _IOW(GPIO_IOC_MAGIC,2,sizeof(GPIO_Data_S))#define GPIO_IO_READ _IOWR(GPIO_IOC_MAGIC,3,sizeof(GPIO_Data_S))#endif

 

驱动层代码test.c

/*************linux headers**************/#include <linux/types.h>#include <linux/fs.h>#include <linux/mm.h>#include <linux/errno.h>#include <linux/module.h>#include <linux/moduleparam.h>#include <linux/kernel.h>#include <asm/uaccess.h>#include <linux/cdev.h>#include <linux/ioctl.h>#include <linux/slab.h>#include <linux/fcntl.h>#include <asm/segment.h>#include <asm/io.h>#include <asm/arch/regs-gpio.h>#include "ioctl_c.h"//设备主次设备号unsigned int test_major=253;unsigned int test_minor=0;struct cdev cdevc;MODULE_LICENSE("Dual BSD/GPL");GPIO_Data_S led;static void led_ctl(){//G50 时写寄存器，具体参见s3c2440 datasheet//这里主要是控制开发板的led等闪烁，每秒闪以下if(led.port=='G'&& led.bit==5 && led.value==0){printk("G50/n");__raw_writel(0x400,S3C2410_GPGCON); __raw_writel(0xffdf,S3C2410_GPGDAT);}//G60 时写寄存器else if(led.port=='G' && led.bit==6 && led.value==0){printk("G60/n");__raw_writel(0x1000,S3C2410_GPGCON); __raw_writel(0xffbf,S3C2410_GPGDAT);}}static int read_test(struct file *file,char *buf,int count ,loff_t *f_pos){printk("/n read_test");printk("%d",count);return count;}static int write_test(struct file *file,const char *buf,int count, loff_t *f_pos){printk("/n write_test");return count;}static int ioctl_test(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg){if(copy_from_user(&led,arg,sizeof(GPIO_Data_S))){return - EFAULT;}printk("%c %d %d/n",led.port,led.bit,led.value);printk("/n ioctl_test");switch(cmd){case GPIO_IO_SET_GPG :led_ctl();break;case GPIO_IO_GET_GPG :led_ctl();break;//case GPIO_IO_WRITE :printk("cmd3") ;break;//case GPIO_IO_READ :printk("cmd3") ;break;default:break;}return cmd;}static int open_test(struct inode *inode,struct file *file){printk("/n open_test");return 0;}static void release_test(struct inode *inode,struct file *file){printk("/n release_test");}struct file_operations test_fops = {.owner=THIS_MODULE,.read=read_test,.write=write_test,.open=open_test,.ioctl=ioctl_test,.release=release_test,};int simple_c_init_module(void){int result;dev_t dev = 0;dev=MKDEV(test_major,test_minor);result = register_chrdev_region(dev,1,"test");printk("major= %d,minor=%d /n",test_major,test_minor);if(result < 0){printk(KERN_INFO "test : can't get major number/n");return result;}cdev_init(&cdevc,&test_fops);cdevc.owner= THIS_MODULE;cdevc.ops=&test_fops;result=cdev_add(&cdevc,dev,1);if(result)printk("Error %d adding test",result);return 0;}void simple_c_cleanup_module(void){dev_t dev=0;dev = MKDEV(test_major,test_minor);cdev_del(&cdevc);unregister_chrdev_region(dev,1);}module_init(simple_c_init_module);module_exit(simple_c_cleanup_module);

 

编译需要makefile

# To build modules outside of the kernel tree, we run "make"# in the kernel source tree; the Makefile these then includes this# Makefile once again.# This conditional selects whether we are being included from the# kernel Makefile or not.ifeq ($(KERNELRELEASE),) # Assume the source tree is where the running kernel was built # You should set KERNELDIR in the environment if it's elsewhere# KERNELDIR ?= /lib/modules/$(shell uname -r)/buildKERNELDIR = /home/utu-linux_for_s3c2440_V1.5.3#KERNELDIR=$(KDIR)# # The current directory is passed to sub-makes as argument PWD := $(shell pwd)modules:$(MAKE) -C $(KERNELDIR) M=$(PWD) modulesmodules_install:$(MAKE) -C $(KERNELDIR) M=$(PWD) modules_installclean:rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions.PHONY: modules modules_install cleanelse # called from kernel build system: just declare what our modules are obj-m := test.oendif