Linux 裝置驅動之 ioctl 小試牛刀（1）

    ioctl是廣大人民群眾喜聞樂見的函數之一，這裡略作筆記，把以前寫的代碼整理以下。

 

應用測試程式main.c

#include <stdio.h><br />#include <sys/types.h><br />#include <sys/stat.h><br />#include <fcntl.h><br />#include <unistd.h><br />#include <linux/ioctl.h><br />#include "../ioctl_c.h"<br />GPIO_Data_S led_ctl;<br />int main(int argc, char **argv)<br />{<br />int testdev = 0;<br />int i = 0;<br />int erro = 0;<br />char buf[10];</p><p>//開啟裝置檔案<br />testdev = open ("/dev/test",O_RDWR);<br />if(testdev == -1)<br />{<br />printf("Cann't open file...../n");<br />exit(0);<br />}<br />while(1)<br />{<br />//led_ctl結構賦值<br />led_ctl.port='G';<br />led_ctl.bit=5;<br />led_ctl.value=0;</p><p>//調用ioctl函數<br />ioctl(testdev,GPIO_IO_SET,&led_ctl);<br />ioctl(testdev,GPIO_IO_WRITE,&led_ctl);<br />ioctl(testdev,GPIO_IO_READ,&led_ctl);<br />sleep(1);</p><p>led_ctl.port='G';<br />led_ctl.bit=6;<br />led_ctl.value=0;<br />ioctl(testdev,GPIO_IO_SET,&led_ctl);<br />ioctl(testdev,GPIO_IO_WRITE,&led_ctl);<br />ioctl(testdev,GPIO_IO_READ,&led_ctl);<br />sleep(1);<br />}<br />close(testdev);<br />}<br />/*<br />mknod /dev/test c 253 0<br />*/

 

ioctl.h

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

 

驅動層代碼test.c

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

 

編譯需要makefile

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