📄 vvdriver.c
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/*
Author: Johnny Chen
*/
//
// 提供底层读写等基本功能
//
// 描 述: FAT文件系统在PC上编译的虚拟卷驱动程序（底层驱动）
//
////////// 虚拟卷: 所有操作定位到volume.dat ///////////
#include "config.h"
#include "vvdriver.h"
char *vv_name_buf;
char *vv_name[3] = {
"volume.dat",
"128m_fat32_512_label(no).img",
"32m_fat_512_label(fat).img",
};
uint8 VV_Initialize(void);
uint8 VV_ReadBlock(uint32 blockaddr, uint8 *buf);
uint8 VV_WriteBlock(uint32 blockaddr, uint8 *buf);
uint32 VV_GetVolumeFirstSect(uint8 Device)
{
uint8 buffer[512];
uint32 RelaStaSect;
VV_ReadBlock(0, buffer); /* 读SD卡的0块 */
if((buffer[510]==0x55)&&(buffer[511]==0xAA))
{
if(((buffer[0]==0xEB)&&(buffer[2]==0x90))||(buffer[0] == 0xE9))/**/
{
RelaStaSect = 0;
}
else
{
RelaStaSect = buffer[454]+
buffer[455]*0x100 +
buffer[456]*0x10000 +
buffer[457]*0x1000000;
}
}
return RelaStaSect;
}
/*********************************************************************************************************
** 函数名称: CFCammand
** 功能描述: 底层驱动程序与上层的接口程序
**
** 输 入: Cammand：DISK_INIT：驱动程序初始化
** DISK_CLOSE：关闭驱动器（移除驱动程序）
** DISK_CREATE_BOOT_SECTOR：重建引导扇区
** DISK_READ_SECTOR：读扇区
** DISK_WRITE_SECTOR：写扇区
** Parameter：剩余参数
** 输 出: DISK_READ_OK：读扇区完成
** DISK_READ_NOT_OK：读扇区失败
** DISK_WRITE_OK：写扇区完成
** DISK_WRITE_NOT_OK：写扇区失败
** DISK_INIT_OK：初始化完成
** DISK_INIT_NOT_OK：初始化失败
** BAD_DISK_COMMAND：无效的命令
** 全局变量: 无
** 调用模块: 无
**
** 作 者: 陈明计
** 日 期: 2003年9月3日
**-------------------------------------------------------------------------------------------------------
** 修改人:
** 日 期:
**------------------------------------------------------------------------------------------------------
********************************************************************************************************/
uint16 VVCammand(uint8 Cammand, void *Parameter)
{
uint8 ret;
uint16 rt;
Disk_RW_Parameter * Dp;
Disk_Info *DiskInfo;
Dp = (Disk_RW_Parameter *)Parameter;
switch (Cammand)
{
case DISK_INIT: /*设备初始化*/
rt = DISK_INIT_NOT_OK;
ret = VV_Initialize();
if (ret == VOL_NO_ERR)
{
DiskInfo = GetEmptyDiskInfoAddr();
if (DiskInfo != NULL)
{
DiskInfo->DiakCommand = VVCammand;
DiskInfo->RsvdForLow = VV_GetVolumeFirstSect(0);/*获取卷首扇区*/
rt = DISK_INIT_OK;
}
}
break;
case DISK_CLOSE:
rt = RETURN_OK;
break;
case DISK_READ_SECTOR: /*读扇区*/
rt = DISK_READ_NOT_OK;
if(VV_ReadBlock(Dp->SectorIndex + Dp->RsvdForLow,Dp->Buf) == VOL_NO_ERR)
rt = DISK_READ_OK;
break;
case DISK_WRITE_SECTOR: /*写扇区*/
rt = DISK_WRITE_NOT_OK;
if(VV_WriteBlock(Dp->SectorIndex + Dp->RsvdForLow,Dp->Buf) == VOL_NO_ERR)
rt = DISK_WRITE_OK;
break;
default:
rt = BAD_DISK_COMMAND;
break;
}
return rt;
}
#define BOOT_SEC_BUF_SIZE (512*3)
uint16 boot_sec_buf_index = 0;
uint8 boot_sec_buf[BOOT_SEC_BUF_SIZE];
void BS_buf_write_byte(uint8 ch)
{
if (boot_sec_buf_index < BOOT_SEC_BUF_SIZE) {
boot_sec_buf[boot_sec_buf_index] = ch;
boot_sec_buf_index++;
if(boot_sec_buf_index%6 == 0)
printf("\n");
printf("%4lu-0x%02x | ", boot_sec_buf_index, ch);
}
else
{
printf("\n BOOT_SEC_BUF_SIZE: %lu, boot_sec_buf_index: %lu, ch: 0x%02x", BOOT_SEC_BUF_SIZE, boot_sec_buf_index, ch);
printf("\n boot_sec_buf OP error: overflow.");
getchar();
}
}
// 功能描述: 初始化virtual volume (1)建虚拟卷文件 (2)创建引导扇区
// 输 入: 无
// 输 出: 0: 正确 >0: 错误码
uint8 VV_Initialize(void)
{
FILE *fp;
uint8 ret = VOL_NO_ERR;
fp = fopen(VIRTUAL_VOL_NAME, "rb+");
if (fp == NULL) // 若没有卷文件则创建一个虚拟卷文件
{
printf("\n#Volume data file isnot exist, creating ... ");
fp = fopen(VIRTUAL_VOL_NAME, "wb");
if (fp == NULL)
printf("\n!fat32 init error: creat volume data file failed!");
else
{
if(fseek(fp, SIZE_VOL - 1, SEEK_SET) == 0)
{
printf("\n 1..");
if (0xff == fputc(0xff, fp))
{
printf("2..");
fseek(fp, -1, SEEK_CUR);
if (0x00 == fputc(0x00, fp))
printf("3.");
printf("creat volume file done (size: %lu)", SIZE_VOL);
}
else
{
printf("\nVolume file rw error!!");
ret = VOL_ERR;
goto EXIT;
}
#if FORMAT_VOL_QUICK
printf("\n--- now format volume file ---");
/* 创建引导扇区 共3个扇区 */
printf("\nCreating boot sector ... ");
if(fseek(fp, ADDR_RESEV, SEEK_SET) == 0)
{
uint16 i;
memset(boot_sec_buf, 0, BOOT_SEC_BUF_SIZE);
boot_sec_buf_index = 0;
do {
/* -- PARTITION BOOT RECORD -- */
BS_buf_write_byte(0xEB); /* JMP inst to PBR boot code */
BS_buf_write_byte(0x3C);
BS_buf_write_byte(0x90);
BS_buf_write_byte('M'); /* OEM name */
BS_buf_write_byte('S');
BS_buf_write_byte('W');
BS_buf_write_byte('I');
BS_buf_write_byte('N');
BS_buf_write_byte('4');
BS_buf_write_byte('.');
BS_buf_write_byte('1');
BS_buf_write_byte((uint8)SIZE_SEC); /* number of bytes per sector */
BS_buf_write_byte((uint8)(SIZE_SEC >> 8));
BS_buf_write_byte(SEC_PER_CLUS); /* Number of sector per cluster */
BS_buf_write_byte(SEC_NUM_RESEV); /* number of reserved sector */
BS_buf_write_byte(SEC_NUM_RESEV >> 8);
BS_buf_write_byte(FAT_NUM); /* Number of FAT */
BS_buf_write_byte(0x00); /* number of root directory entries, fat32 must be 0x0000 */
BS_buf_write_byte(0x00);
/* Total Sectors (FAT16)*/
BS_buf_write_byte(0x00);
BS_buf_write_byte(0x00);
BS_buf_write_byte(HARD_DISK); /* Media Byte */
/* Number of sector in each FAT */
BS_buf_write_byte(0x00); /* 0x0000 for FAT32 */
BS_buf_write_byte(0x00);
BS_buf_write_byte(0x00); /* Number of sectors on a track */
BS_buf_write_byte(0x00);
BS_buf_write_byte(0x00); /* Number of heads */
BS_buf_write_byte(0x00);
BS_buf_write_byte(0x00); /* Number of hidden sectors */
BS_buf_write_byte(0x00);
BS_buf_write_byte(0x00);
BS_buf_write_byte(0x00);
/* number of sectors > 65535 */
BS_buf_write_byte((uint8)SEC_NUM_VOL);
BS_buf_write_byte((uint8)(SEC_NUM_VOL >> 8));
BS_buf_write_byte((uint8)(SEC_NUM_VOL >> 16));
BS_buf_write_byte((uint8)(SEC_NUM_VOL >> 24));
BS_buf_write_byte((uint8)SEC_NUM_FAT); /* nb sector for each fat */
BS_buf_write_byte((uint8)(SEC_NUM_FAT >> 8));
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