Per PCIe r6.0, sec 2.3.2, when a Root Complex handles a Completion with Request Retry Status for a Configuration Read Request that includes both bytes of the Vendor ID field, it must complete the Request to the host by returning 0001h for the Vendor ID and all 1's for any additional bytes. Previously we only returned the 0001h Vendor ID value if we got an RRS completion for reads of exactly 4 bytes. A read of 2 bytes would not qualify, although the spec says it should. Check for reads of 2 or more bytes including the Vendor ID. I don't think this will fix any observable problems because RRS only applies to the first config reads after reset, and those are all currently dword (4-byte) reads.
Unified · Split
| @@ -1153,11 +1153,11 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn, · 1152 unmodified lines | |||
| 1153 | size, val); | 1153 | size, val); |
| 1154 | 1154 | ||
| 1155 | /* | 1155 | /* |
| 1156 | * Completion Retry Status is possible to return only when reading all | 1156 | * Completion Retry Status is possible to return only when reading |
| 1157 | * 4 bytes from PCI_VENDOR_ID and PCI_DEVICE_ID registers at once and | 1157 | * both bytes from PCI_VENDOR_ID at once and CRSSVE flag on Root |
| 1158 | * CRSSVE flag on Root Bridge is enabled. | 1158 | * Port is enabled. |
| 1159 | */ | 1159 | */ |
| 1160 | allow_crs = (where == PCI_VENDOR_ID) && (size == 4) && | 1160 | allow_crs = (where == PCI_VENDOR_ID) && (size >= 2) && |
| 1161 | (le16_to_cpu(pcie->bridge.pcie_conf.rootctl) & | 1161 | (le16_to_cpu(pcie->bridge.pcie_conf.rootctl) & |
| 1162 | PCI_EXP_RTCTL_CRSSVE); | 1162 | PCI_EXP_RTCTL_CRSSVE); |
| 1163 | 1163 | ||