字元裝置模板

源**：

#include #include 

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
//module_param(mem_major, int, s_irugo);  
#define memdev_major        260     /*預設的mem的主裝置號*/  
#define memdev_nr_devs      2       /*裝置數*/  
#define memdev_size         4096  
#define char_dev_name       "memdev"
static
int mem_major = 0; //
memdev_major;  
struct
class *pclass =null;  
struct
cdev my_dev;   
int mem_open(struct inode *inode, struct file *filp)  
int mem_release(struct inode *inode, struct file *filp)  
/*'k'為幻數，要按照linux核心的約定方法為驅動程式選擇ioctl編號，
應該首先看看include/asm/ioctl.h和documentation/ioctl-number.txt這兩個檔案.
對幻數的編號千萬不能重複定義，如ioctl-number.txt已經說明『k'的編號已經被占用的範圍為：
'k'    00-0f    linux/spi/spidev.h    conflict!
'k'    00-05    video/kyro.h        conflict!
所以我們在這裡分別編號為0x1a和0x1b
*/#define cmd_magic   'k'
#define mem_cmd1    _io(cmd_magic, 0x1a)
#define mem_cmd2    _io(cmd_magic, 0x1b)
int temp_data = 0
;static
int mem_ioctl( struct file *file, unsigned int cmd, unsigned long
arg)
//printk(kern_notice"ioctl cmd%d done!\n",temp);    
return0;
}static
const
struct file_operations mem_fops =;  
static
int memdev_init(void
)   
else    
if (result < 0
)          
return
result;  
cdev_init(&my_dev, &mem_fops);  
my_dev.owner =this_module;  
my_dev.ops = &mem_fops;  
cdev_add(&my_dev, mkdev(mem_major, 0
), memdev_nr_devs);  
pclass =class_create(this_module, char_dev_name);  
if(is_err(pclass))  
device_create(pclass, null, devno, null, char_dev_name);  
return
0;  
failed:   
cdev_del(&my_dev);
unregister_chrdev_region(devno, 
1);  
return
result;  
}    
static
void memdev_exit(void
)    
module_author(
"derek yi
");  
module_license(
"gpl
");  
module_init(memdev_init);  
module_exit(memdev_exit);

makefile：

ifneq ($(kernelrelease),)

obj-m:=memdev.o
else
kerneldir:=/lib/modules/$(shell uname -r)/build
pwd:=$(shell pwd)
default
:    $(make) -c $(kerneldir) m=$(pwd) modules
clean:
rm -rf *.o *.mod.c *.mod.o *.ko
endif

測試**：

#include #include 

#include 
#include 
#include 
#include 
#include 
#include 
#define cmd_magic   'k'
#define mem_cmd1    _io(cmd_magic, 0x1a) //
write
#define mem_cmd2    _io(cmd_magic, 0x1b) //
read
intmain()
ret = ioctl(fd, mem_cmd2, &rdata);
printf(
"ioctl: ret=%d rdata=%d\n
", ret, rdata);
wdata = 42
;    ret = ioctl(fd, mem_cmd1, &wdata);
ret = ioctl(fd, mem_cmd2, &rdata);
printf(
"ioctl: ret=%d rdata=%d\n
", ret, rdata);
close(fd);
return0;
}

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