Resizable BAR Control Register 4 @0x1a8
This register controls the aperture setting of the first memory BAR of the associated Physical Function, and has a field that specifies the number of resizable BARs configurable through the Resizable BAR Capability Structure. This register is active only when the Resizable BAR Capability is enabled for the Physical Function by setting the Enable Resizable BAR Capability bit (bit 31) of the associated Physical Function BAR Configuration Register. When the Resizable BAR Capability is not enabled, a read from this location returns all zeroes. When the Resizable BAR Capability is enabled, all valid fields of this register can be modified from the local management bus.
| Bits | SW | Name | Description | Reset |
|---|---|---|---|---|
| 2:0 | R/W | BAR Index [BARI] | Specifies the index of the BAR controlled by this register. This field can be modified independently for each PF from the local management bus. | 0x0 |
| 4:3 | R | Reserved [R2] | Reserved | 0x0 |
| 7:5 | R/W | Resizable BAR Count [RBARC] | Specifies the number of BARs that can be configured through the Resizable BAR Capability Structure for this PF. This field can be modified independently for each PF from the local management bus. | 0x0 |
| 12:8 | R/W | BAR Size [BARS] | When the Resizable BAR Capability is enabled for the Physical Function, this field controls the BAR aperture for the first BAR of the PF (0 = 1M, 1 = 2M, ..., 12 = 4G). This field can be modified independently for each PF from the local management bus. | 0x0 |
| 31:13 | R | Reserved [R3] | Reserved | 0x0 |