Chapter 6 Target Mode
Page 6 - 10 |
| Target Selection Data Structure |
Target
Selection Data
Structure
The Target Selection Data Structure is used by the adapter to give the Host driver information about the transaction requested of the adapter by a SCSI initiator.
The address of the area reserved by the Host to accommodate the Target Selection Data Structure, is passed to the RF3880 in the Target Mode Enable command (described in Chapter 7). The structure has the following format:
Address |
| Byte Memory Address |
|
| |
Offset | Offset + 0 | Offset + 1 | Offset + 2 |
| Offset + 3 |
|
|
|
|
|
|
00H |
| Command Identifier |
|
| |
|
|
|
|
|
|
04H | SCSI flags | Reserved | Error |
| Flags |
08H | Msg Byte Rcd | CDB Length | Init ID |
| ID Msg Received |
|
|
|
|
|
|
0CH | Queue Tag Msg | Queue Tag ID |
| Reserved | |
|
|
|
|
|
|
10H |
| SCSI CDB Received |
|
| |
|
|
|
|
| |
14H |
| SCSI CDB Received |
|
| |
|
|
|
|
| |
18H |
| SCSI CDB Received |
|
| |
|
|
|
|
|
|
1CH |
| Reserved |
|
| Semaphore |
Table 44: Target Selection Data Structure
To buffer Host operations from Target Mode operations, information destined for the Target Selection Data Structure is queued by the RF3880, as initiator selections occur on the SCSI bus. Information from about sixty selections from initiators can be queued at a time. See Chapter 8 for more information about the Selection Queue.
Command Identifier
The Command Identifier that labels the Target Mode Enable command is copied by the adapter into the Target Selection Data Structure when a selection occurs. The Host driver may use this for verification of the source of the selection data.
21020285 D | User’s Guide |