实验
驱动文件hello.c
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#define HELLO_MAJOR 231
#define DEVICE_NAME "HelloModule"
static int hello_open(struct inode *inode, struct file *file){
printk(KERN_EMERG "hello open.\n");
return 0;
}
static int hello_write(struct file *file, const char __user * buf, size_t count, loff_t *ppos){
printk(KERN_EMERG "hello write.\n");
return 0;
}
static struct file_operations hello_flops = {
.owner = THIS_MODULE,
.open = hello_open,
.write = hello_write,
};
static int __init hello_init(void){
int ret;
ret = register_chrdev(HELLO_MAJOR,DEVICE_NAME, &hello_flops);
if (ret < 0) {
printk(KERN_EMERG DEVICE_NAME " can't register major number.\n");
return ret;
}
printk(KERN_EMERG DEVICE_NAME " initialized.\n");
return 0;
}
static void __exit hello_exit(void){
unregister_chrdev(HELLO_MAJOR, DEVICE_NAME);
printk(KERN_EMERG DEVICE_NAME " removed.\n");
}
module_init(hello_init);
module_exit(hello_exit);
MODULE_LICENSE("GPL");
编译驱动所需的Makefile
ifneq ($(KERNELRELEASE),)
MODULE_NAME = hellomodule
$(MODULE_NAME)-objs := hello.o
obj-m := $(MODULE_NAME).o
else
KERNEL_DIR = /lib/modules/`uname -r`/build
MODULEDIR := $(shell pwd)
.PHONY: modules
default: modules
modules:
make -C $(KERNEL_DIR) M=$(MODULEDIR) modules
clean distclean:
rm -f *.o *.mod.c .*.*.cmd *.ko
rm -rf .tmp_versions
endif
1、编译驱动
#make
2、编译上层应用
#gcc hellotest.c -o hellotest
3、加载驱动
#insmod hellomodule.ko
insmod加载驱动的时候,会调用函数hello_init(),打印的调试信息如下。
但是在"/proc/devices"中看不到已经加载的模块。
posted on 2019-12-22 18:27 洛桑曲珍20199301 阅读(160) 评论(0) 编辑 收藏 举报