ATS Page Request Control Status Register @0x644
ATS Page Request Control Status Register.
| Bits | SW | Name | Description | Reset |
|---|---|---|---|---|
| 0 | R/W | ATS Page Request Enable [ATSPREN] | This field, when set, indicates that the Page Request Interface is allowed to make page requests. If this field is Clear, the Page Request Interface is not allowed to issue page requests. If both this field and the Stopped field are Clear, then the Page Request Interface will not issue new page requests, but has outstanding page requests that have been transmitted or are queued for transmission. When the Page Request Interface is transitioned from not-Enabled to Enabled, its status flags (i.e., Stopped, Response Failure, and Unexpected Response flags) are cleared. Enabling a Page Request Interface that has not successfully Stopped has indeterminate results. Default value is 0b. | 0x0 |
| 1 | W | ATS Page Request Reset [ATSPRRST] | When the Enable field is clear, or is being cleared in the same register update that sets this field, writing a 1b to this field clears the associated implementation dependent page request credit counter and pending request state for the associated Page Request Interface. No action is initiated if this field is written to 0b or if this field is written with any value while the Enable field is Set. Reads of this field through PCIe link return 0b. Once this field is written by '1' through PCIe link, a vector output (ATS_PR_CONTROL_REG_RESET) of controller gets set. Client logic after clearing the credit counter and pending request state, has to clear this register through local management interface. | 0x0 |
| 15:2 | R | RSVD | RSVD | 14'h0000 |
| 16 | R/WOCLR | ATS PR Response Failure [ats_pr_rf] | This field, when Set, indicates that the Function has received a PRG Response Message indicating a Response Failure. The Function expects no further responses from the host (any received are ignored). This field is Set by the Function and Cleared when a one is written to the field. For SR-IOV, this field is Set in the PF if any associated Function (PF or VF) receives a PRG Response Message indicating Response Failure. Default value is 0b. | 0x0 |
| 17 | R/WOCLR | ATS Unexpected Page Request Group Index [ATSPPRUPRGI] | This field, when Set, indicates that the Function has received a PRG Response Message containing a PRG index that has no matching request. This field is Set by the Function and cleared when a one is written to the field. For SR-IOV, this field is Set in the PF if any associated Function (PF or VF) receives a PRG Response Message that does has no matching request. Default value is 0b. | 0x0 |
| 23:18 | R | RSVD | RSVD | 6'h00 |
| 24 | R | ATS Page Request Stopped [ATSPRSTOP] | When this field is Set, the associated page request interface has stopped issuing additional page requests and that all previously issued Page Requests have completed. When this field is Clear the associated page request interface either has not stopped or has stopped issuing new Page Requests but has outstanding Page Requests. This field is only meaningful if Enable is Clear. If Enable is Set, this field is undefined. When the Enable field is Cleared, after having been previously Set, the interface transitions to the stopping state and Clears this field. After all page requests currently outstanding at the Function(s) have completed, this field is Set and the interface enters the disabled state. If there were no outstanding page requests, this field may be Set immediately when Enable is Cleared. Resetting the interface will cause an immediate transition to the disabled state. While in the stopping state, receipt of a Response Failure message will result in the immediate transition to the disabled state (Setting this field). For SR-IOV, this field is Set only when all associated Functions (PF and VFs) have stopped issuing page requests. Default value is 1b. | 0x1 |
| 30:25 | R | RSVD | RSVD | 6'h00 |
| 31 | R | PRG Response PASID Required [ATSPRGRPR] | If Set, the Function expects a PASID TLP Prefix on PRG Response Messages when the corresponding Page Requests had a PASID TLP Prefix. If Clear, the Function does not expect PASID TLP Prefixes on any PRG Response Message. Function behavior is undefined if this bit is Clear and the Function receives a PRG Response Message with a PASID TLP Prefix. Function behavior is undefined if this bit is Set and the Function receives a PRG Response Message with no PASID TLP Prefix when the corresponding Page Requests had a PASID TLP Prefix. | 0x1 |