linux设备驱动--scull

《linux设备驱动》一书中的例程都可以在PC主机的linux环境中运行，而不必下载到arm平台的linux/android环境中

linux设备驱动--scull

查看系统版本

[email protected]:~/linux_driver/hello$ uname -r
4.2.0-27-generic
[email protected]:~/linux_driver/hello$ cat /etc/issue
Ubuntu 14.04.5 LTS \n \l


[email protected]:~/linux_driver/hello$ vim hello.c 
  1 /* hello.c */
  2 #include <linux/init.h>
  3 #include <linux/module.h>
  4 MODULE_LICENSE("leo BSD/GPL");
  5 static int hello_init(void)
  6 {
  7     printk(KERN_ALERT "Hello, world\n");
  8     return 0;
  9 }
 10 static void hello_exit(void)
 11 {
 12     printk(KERN_ALERT "Goodbye, Hello world\n");
 13 }
 14 module_init(hello_init);
 15 module_exit(hello_exit);
~                                                                                                  
~

Makefile

[email protected]:~/linux_driver/hello$ vim Makefile 
  1 obj-m += hello.o
  2     CURRENT_PATH:=$(shell pwd)
  3     LINUX_KERNEL_PATH:=/lib/modules/$(shell uname -r)/build
  4 all:
  5         $(MAKE) -C $(LINUX_KERNEL_PATH) M=$(CURRENT_PATH) modules
  6 clean:
  7         rm -rf .*.cmd *.o *.mod.c *.ko .tmp_versions
  8

依赖于系统源码内核目录 /usr/src/linux-headers-4.2.0-27

在/home/sunhz/linux_driver/hello 使用make 命令编译生成 hello.ko

加载ko动态库

[email protected]:~/linux_driver/hello$ sudo insmod hello.ko
[email protected]:~/linux_driver/hello$

查看log打印

[email protected]:~/linux_driver/hello$ sudo cat /var/log/syslog | grep Hello
Mar 15 14:11:30 R720xd kernel: [337056.403621] Hello, world
[email protected]:~/linux_driver/hello$

卸载ko动态库

[email protected]:~/linux_driver/hello$ sudo rmmod hello.ko

[email protected]:~/linux_driver/hello$ sudo cat /var/log/syslog | grep Hello
Mar 15 14:11:30 R720xd kernel: [337056.403621] Hello, world
Mar 15 14:13:17 R720xd kernel: [337163.514790] Goodbye, Hello world

可以查看到源码

printk(KERN_ALERT "Hello, world\n");

printk(KERN_ALERT "Goodbye, Hello world\n");

成功打印

linux设备驱动--scull

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