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#ifndef __KERNEL__
#define __KERNEL__
#endif
#ifndef MODULE
#define MODULE
#endif
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h> /* printk() */
#include <linux/init.h> /* __init __exit */
#include <linux/types.h> /* size_t */
#include <linux/fs.h> /* file_operation */
#include <linux/blk.h>
#include <linux/hdreg.h> /* geo */
//#include /* Error number */
//#include /* udelay */
#include <asm/uaccess.h> /* copy_to_user, copy_from_user */
#define DRIVER_NAME "Ram Disk"
#define PRINTK(fmt, arg...) printk(KERN_NOTICE fmt, ##arg)
static int myBlockDriver_Major = 0; /* Driver Major Number */
/* Vitual Driver Buffer */
#define NUM_RAMDISKS 1
#define DISK_SIZE (1UL*1024UL*1024UL)
#define BYTE_PER_SECTOR (512)
static unsigned char rd_buffer[NUM_RAMDISKS][DISK_SIZE];/* Vitual Buffer */
static unsigned long rd_length[NUM_RAMDISKS]; /* Size of RAM disks in bytes */
static int rd_hardsec[NUM_RAMDISKS]; /* Size of real blocks in bytes */
static int rd_blocksizes[NUM_RAMDISKS]; /* Size of 1024 byte blocks :) */
static int rd_kbsize[NUM_RAMDISKS]; /* Size in blocks of 1024 bytes */
//static devfs_handle_t devfs_handle;
//static struct block_device *rd_bdev[NUM_RAMDISKS]; /* Protected device data */
/* Block Driver Operation Functions */
static int myBlockDriver_open(struct inode *inode, struct file *filp)
{
int Minor = MINOR(inode->i_rdev); //这里的从设备号是有意义的，和字符设备要区分，
if (Minor >= NUM_RAMDISKS) //这里从设备号可以用来区别具体的盘符。
return -ENXIO;
MOD_INC_USE_COUNT;
PRINTK("myBlockDriver open called!\n");
return 0;
}
static int myBlockDriver_release(struct inode *inode, struct file *filp)
{
int Minor = MINOR(inode->i_rdev); //这里的从设备号是有意义的，和字符设备要区分，
if (Minor >= NUM_RAMDISKS)
return -ENXIO;
MOD_DEC_USE_COUNT;
PRINTK("myBlockDriver release called!\n");
return 0;
}
static int myBlockDriver_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
int error = -EINVAL;
int Minor;
//对一些命令的响应
// long size;
struct hd_geometry geo;
PRINTK("myBlockDriver ioctl called(%d)!\n", cmd);
if (!inode || !inode->i_rdev)
return error;
Minor = MINOR(inode->i_rdev);
switch(cmd)
{
case BLKGETSIZE: /* Return device size */
if (!arg)
break;
error = put_user(rd_kbsize[Minor] << 1, (unsigned long *) arg);
error = 0;
break;
case BLKGETSIZE64:
error = put_user((u64)rd_kbsize[Minor]<<10, (u64*)arg);
break;
case HDIO_GETGEO:
PRINTK("HDIO_GETGEO called!\n");
geo.cylinders = rd_length[Minor] >> 6;// 除（4*16）相当于右移6位
geo.heads = 4;
geo.sectors = 16;
geo.start = 0;
copy_to_user((void *)arg, &geo, sizeof(geo));
break;
default:
return blk_ioctl(inode->i_rdev, cmd, arg);
}
return error;
}
static int myBlockDriver_check_media_change(kdev_t dev)//对于热插拔的设备需要在这里填充代码
{
return 0;
}
static int myBlockDriver_revalidate(kdev_t dev)//通常的磁盘的大小、具体数据信息的更新在这里完成
{
return 0;
}
/* Block Driver Operation structure */
static struct block_device_operations myBlockDriver_fops = {
owner: THIS_MODULE,
open: myBlockDriver_open,
release: myBlockDriver_release,
ioctl: myBlockDriver_ioctl,
check_media_change:myBlockDriver_check_media_change,
revalidate: myBlockDriver_revalidate,
};
/* Block Driver Data Transfer Function */
static int myBlockDriver_make_request(request_queue_t *queue, int rw, struct buffer_head *bh)
{
unsigned long flag;
int Minor = MINOR(bh->b_rdev);
long offset = bh->b_rsector * 512; /* 0 means the start sector of the disk*/
unsigned char *start_addr = bh->b_data;
size_t len = bh->b_size;
switch(rw)
{
case READA:
case READ:
local_irq_save(flag);//进入临界区
memcpy(start_addr, &rd_buffer[Minor][offset], len);
local_irq_restore(flag);//推出临界区
bh->b_end_io(bh, 1);//调用回调函数，通知内核成功完成操作
break;
case WRITE:
local_irq_save(flag);
memcpy(&rd_buffer[Minor][offset], start_addr, len);
local_irq_restore(flag);
bh->b_end_io(bh, 1);
break;
default:
bh->b_end_io(bh,0);
break;
}
return 0;
}
/* Module Init & Exit function */
#ifdef CONFIG_DEVFS_FS
devfs_handle_t devfs_myDriver_dir;
#endif
static int __init myModule_init(void)
{
int i;
/* Module init code */
PRINTK("myModule_init\n");
/* Init device structure*/
for(i = 0; i < NUM_RAMDISKS; i++)
{
rd_length[i] = DISK_SIZE; /* Size of RAM disks in bytes */
rd_hardsec[i] = BYTE_PER_SECTOR; /* Size of real blocks in bytes */
rd_blocksizes[i] = 1024; /* Size of 1024 byte blocks :) */
rd_kbsize[i] = DISK_SIZE/1024; /* Size in blocks of 1024 bytes */
}
/* Driver register */
myBlockDriver_Major = register_blkdev(0, DRIVER_NAME, &myBlockDriver_fops);
if(myBlockDriver_Major < 0)
{
PRINTK("register char device fail!\n");
return myBlockDriver_Major;
}
PRINTK("register myDriver OK! Major = %d\n", myBlockDriver_Major);
//一下的部分是字符型设备与块设备最主要区别的地方，真正的数据传输在这里发生。
//调用blk_queue_make_request来替换内核的make_request
blk_queue_make_request(BLK_DEFAULT_QUEUE(myBlockDriver_Major), myBlockDriver_make_request);
PRINTK("register make request function OK\n");
#ifdef CONFIG_DEVFS_FS
devfs_myDriver_dir = devfs_mk_dir(NULL, "blkdrv", NULL);
devfs_register_series(devfs_myDriver_dir, "%u", NUM_RAMDISKS,
DEVFS_FL_DEFAULT, myBlockDriver_Major, 0,
S_IFBLK | S_IRUSR | S_IWUSR,
&myBlockDriver_fops, NULL);
PRINTK("add dev file OK!\n");
#endif
return 0;
}
static void __exit myModule_exit(void)
{
/* Module exit code */
PRINTK("myModule_exit\n");
/* Driver unregister */
if(myBlockDriver_Major > 0)
{
#ifdef CONFIG_DEVFS_FS
devfs_unregister(devfs_myDriver_dir);
#endif
unregister_blkdev(myBlockDriver_Major, DRIVER_NAME);
}
return;
}
MODULE_AUTHOR("xxxx");
MODULE_LICENSE("Dual BSD/GPL");
module_init(myModule_init);
module_exit(myModule_exit);
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