DPA Control and Status Registers @0x1cc
This location contains the DPA Control Register and the DPA Status Register.
| Bits | SW | Name | Description | Reset |
|---|---|---|---|---|
| 4:0 | R | Substate Status [SS] | This field provides the current DPA substate of this Function. This field is writable from the local management bus and must be updated by the local software running on the Endpoint upon completion of a DPA transition to a new substate. | 0x0 |
| 7:5 | R | Reserved [R3] | Reserved | 0x0 |
| 8 | R/WOCLR | Substate Control Enabled [SCE] | This bit enables the Substate Control field. This bit is initialized to 1 by the hardware on a power-on reset or a Function-Level Reset. Software may clear this bit by writing a 1 to this bit position, but cannot set this bit directly through a configuration write. Clearing this bit disables the Substate Control field, thus preventing further substate transitions for this Function. This bit can be set to 0 or 1 through the local management bus by writing a 0 or 1, respectively. | 0x1 |
| 15:9 | R | Reserved [R4] | Reserved | 0x0 |
| 20:16 | R/W | Substate Control [SC] | This field is used to initiate a transition of the Function's DPA to a new substate. To initiate the transition, software must write the desired substate value into this field and wait for the transition latency of the substate for the Function to complete the transition. This field can also be written from the local management bus. All substate transitions are disabled when the Substate Control Enabled bit is 0. The Controller generates a one-cycle pulse on the output DPA_INTERRUPT when the value if this field is changed (bit 0 is for PF 0 and so on). This interrupt informs the client of the request from software to change the DPA substate. In response, the client must read the Substate Control field from this register to determine the new substate, and perform the actions necessary to effect the substate change. On completion of the substate change, the client must update the Substate Status field to reflect the new substate the function is in. | 0x0 |
| 31:21 | R | Reserved [R5] | Reserved | 0x0 |