Description of file IO messages

Read Message Format

Table 1. Read Request

Offset	Type	Name	Description
0	uint8	Handle	This field is a handle that is used to identify PLDM command type.
1	enum8	Option	This field is a read option is used to identify the read file option. See Table 3 for the option.
2:3	uint16	Length	The length in bytes N of data being sent in this part in the ReadInfo field.
Variable	uint8	ReadInfo	Portion of reading information. There will be different reading information according to different ReadOption. See Table 4 and Table 5 for details

Table 2. Read response

Offset	Type	Name	Description
0	int	CompletionCode	value: { PLDM_SUCCESS, PLDM_ERROR_INVALID_DATA, PLDM_ERROR_INVALID_LENGTH }
Variable	uint8	ReadResponse	Portion of reading response. There will be different reading response according to different ReadOption. See Table 6 and Table 7 for details

Table 3. Option of message type

Value	Name	Description
0x00	ReadFileAttribute	Get file size and checksum
0x01	ReadFileData	Get file data

Table 4. ReadInfo Definition when ReadOption is ReadFileAttribute in message type

Offset	Type	Name	Description
0	-	-	No request data

Table 5. ReadInfo Definition when ReadOption is ReadFileData in message type

Offset	Type	Name	Description
0	uint8	TransferFlag	The transfer flag that indiates what part of the transfer this request represents. Possible values: {Start=0x01, Middle=0x02, End=0x04, StartAndEnd=0x05}
1:2	uint16	Offset	Offset in read file.

Table 6. ReadResponse Definition when ReadOption is ReadFileAttribute in message type

Offset	Type	Name	Description
0:1	uint16	Size	This field indicates the size of the entire file, in bytes.
2:5	uint32	Checksum	This field indicates the checksum of the entire file.

Table 7. ReadResponse Definition when ReadOption is ReadFileData in message type

Offset	Type	Name	Description
0	uint8	TransferFlag	The transfer flag that indiates what part of the transfer this response represents. Possible values: {Start=0x01, Middle=0x02, End=0x04, StartAndEnd=0x05}
1:2	uint16	Offset	Offset in read file.
Variable	uint8	FileData	File data can be up to 255 bytes.