Western Digital T13/2132-D manual Security Protocol Commands FN 51h

June 23, 2010 T13/2132-D Revision 3

8.28 Security Protocol Commands (FN 51h)

The purpose of this function is to support the Trusted Computing feature set (see ACS-2), the SECURITY PROTOCOL IN command (see SPC-4), and the SECURITY PROTOCOL OUT command (see SPC-4).

Entry

AH 51h

AL Flags

Bit Description

7 Direction

0 = Send data to the device

1 = Receive data from the device 6:0 Reserved

CX Security Protocol Specific

Specifies data which varies based on the Security Protocol ID. (See ACS-2 or SPC-4)

DH Security Protocol ID

Specifies which security protocol is to be used. (See ACS-2 or SPC-4) DL BIOS device number

ES:BX QWord-aligned pointer to data buffer in memory (see table 33)

Exit

Carry Clear Function completed without error AH Shall be cleared to zero

AL Shall be set to the status of the last INT 13h operation

ES:BX Shall be set to the QWord-aligned pointer to data buffer in memory (see table 33)

Carry Set Function completed with an error

AH Shall be set to the error code

ES:BX Shall be set to the QWord-aligned pointer to data buffer in memory (see table 33)

Table 33 — Data Buffer for Security Protocol Commands

Offset	Type	Description
00h	DWord	Length (bytes) of the Payload Data
		On Entry:
		If the Direction bit is set to one, then this field contains the number
		of bytes to be sent to the device. If Direction bit is cleared to zero,
		then this field contains the expected number of bytes to be received
		from the device, and the buffer shall be large enough to
		accommodate this number, plus 8 bytes.
		On Exit:
		If the Direction bit is cleared to zero, this field contains the actual
		number of bytes received from the device
04h	DWord	Reserved
08h..(Length of Payload Data+8)	Byte	Payload Data
		The content of this data depends on the selected Security Protocol.

Working Draft Enhanced Disk Drive - 4 (EDD-4) 69