我尝试向SSD发出 scsi read(10)和write(10) 。我将此示例代码用作参考/基本代码。
这是我的 scsi 阅读：
#define READ_REPLY_LEN 32
#define READ_CMDLEN 10
void scsi_read()
{
unsigned char Readbuffer[ SCSI_OFF + READ_REPLY_LEN ];
unsigned char cmdblk [ READ_CMDLEN ] =
{ 0x28, /* command */
0, /* lun/reserved */
0, /* lba */
0, /* lba */
0, /* lba */
0, /* lba */
0, /* reserved */
0, /* transfer length */
READ_REPLY_LEN, /* transfer length */
0 };/* reserved/flag/link */
memset(Readbuffer,0,sizeof(Readbuffer));
memcpy( cmd + SCSI_OFF, cmdblk, sizeof(cmdblk) );
/*
* +------------------+
* | struct sg_header | <- cmd
* +------------------+
* | copy of cmdblk | <- cmd + SCSI_OFF
* +------------------+
*/
if (handle_scsi_cmd(sizeof(cmdblk), 0, cmd,
sizeof(Readbuffer) - SCSI_OFF, Readbuffer )) {
fprintf( stderr, "read failed\n" );
exit(2);
}
hex_dump(Readbuffer,sizeof(Readbuffer));
}
这是我的 scsi 写的：
void scsi_write ( void )
{
unsigned char Writebuffer[SCSI_OFF];
unsigned char cmdblk [] =
{ 0x2A, /* 0: command */
0, /* 1: lun/reserved */
0, /* 2: LBA */
0, /* 3: LBA */
0, /* 4: LBA */
0, /* 5: LBA */
0, /* 6: reserved */
0, /* 7: transfer length */
0, /* 8: transfer length */
0 };/* 9: control */
memset(Writebuffer,0,sizeof(Writebuffer));
memcpy( cmd + SCSI_OFF, cmdblk, sizeof(cmdblk) );
cmd[SCSI_OFF+sizeof(cmdblk)+0] = 'A';
cmd[SCSI_OFF+sizeof(cmdblk)+1] = 'b';
cmd[SCSI_OFF+sizeof(cmdblk)+2] = 'c';
cmd[SCSI_OFF+sizeof(cmdblk)+3] = 'd';
cmd[SCSI_OFF+sizeof(cmdblk)+4] = 'e';
cmd[SCSI_OFF+sizeof(cmdblk)+5] = 'f';
cmd[SCSI_OFF+sizeof(cmdblk)+6] = 'g';
cmd[SCSI_OFF+sizeof(cmdblk)+7] = 0;
/*
* +------------------+
* | struct sg_header | <- cmd
* +------------------+
* | copy of cmdblk | <- cmd + SCSI_OFF
* +------------------+
* | data to write |
* +------------------+
*/
if (handle_scsi_cmd(sizeof(cmdblk), 8, cmd,
sizeof(Writebuffer) - SCSI_OFF, Writebuffer )) {
fprintf( stderr, "write failed\n" );
exit(2);
}
}
在下面的例子中，我做
- scsi 读取
- SCSI写
- scsi 读取
我打印了写入数据的十六进制转储（scsi write）和读取的数据（scsi read）
Read(10)
[0000] 00 00 00 44 00 00 00 44 00 00 00 00 00 00 00 00 ...D...D ........
[0010] 00 2C 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........
[0020] 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........
[0030] 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........
[0040] 00 00 00 00 ....
Write(10):
[0000] 00 00 00 00 00 00 00 24 00 00 00 00 00 00 00 00 ........ ........
[0010] 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........
[0020] 00 00 00 00 2A 00 00 00 00 00 00 00 00 00 41 62 ........ ......Ab
[0030] 63 64 65 66 67 00 cdefg.
Read(10):
[0000] 00 00 00 44 00 00 00 44 00 00 00 00 00 00 00 00 ...D...D ........
[0010] 04 00 20 00 70 00 02 00 00 00 00 0A 00 00 00 00 ....p... ........
[0020] 04 00 00 00 41 62 63 64 65 66 67 00 00 00 00 00 ....Abcd efg.....
[0030] 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ........ ........
[0040] 00 00 00 00 ....
再次运行这三个命令后，我应该阅读Abcdefg第一次阅读。对？但是再次运行它们并没有改变。您现在可以假设，我使用的内存仍然具有来自先前函数的数据，但即使我在发生memset(Readbuff,0,sizeof(Readbuff))之前运行，我也会得到相同的结果sys_read()。
我假设，我尝试写入的 LBA 可能被禁止写入，我读取了缓存。但是从 0x00-0xFF 对 LBA 地址进行交互没有任何改变——这意味着，我读取了相同的数据 ( Abcdefg)。
您知道使用 scsi 通用接口进行 scsi 读取或写入的示例实现吗？