diff options
| -rw-r--r-- | drivers/pci/probe.c | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 490031fd210..b47c2dd5b9e 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -984,6 +984,43 @@ void set_pcie_hotplug_bridge(struct pci_dev *pdev) /** + * pci_ext_cfg_is_aliased - is ext config space just an alias of std config? + * @dev: PCI device + * + * PCI Express to PCI/PCI-X Bridge Specification, rev 1.0, 4.1.4 says that + * when forwarding a type1 configuration request the bridge must check that + * the extended register address field is zero. The bridge is not permitted + * to forward the transactions and must handle it as an Unsupported Request. + * Some bridges do not follow this rule and simply drop the extended register + * bits, resulting in the standard config space being aliased, every 256 + * bytes across the entire configuration space. Test for this condition by + * comparing the first dword of each potential alias to the vendor/device ID. + * Known offenders: + * ASM1083/1085 PCIe-to-PCI Reversible Bridge (1b21:1080, rev 01 & 03) + * AMD/ATI SBx00 PCI to PCI Bridge (1002:4384, rev 40) + */ +static bool pci_ext_cfg_is_aliased(struct pci_dev *dev) +{ +#ifdef CONFIG_PCI_QUIRKS + int pos; + u32 header, tmp; + + pci_read_config_dword(dev, PCI_VENDOR_ID, &header); + + for (pos = PCI_CFG_SPACE_SIZE; + pos < PCI_CFG_SPACE_EXP_SIZE; pos += PCI_CFG_SPACE_SIZE) { + if (pci_read_config_dword(dev, pos, &tmp) != PCIBIOS_SUCCESSFUL + || header != tmp) + return false; + } + + return true; +#else + return false; +#endif +} + +/** * pci_cfg_space_size - get the configuration space size of the PCI device. * @dev: PCI device * @@ -1001,7 +1038,7 @@ static int pci_cfg_space_size_ext(struct pci_dev *dev) if (pci_read_config_dword(dev, pos, &status) != PCIBIOS_SUCCESSFUL) goto fail; - if (status == 0xffffffff) + if (status == 0xffffffff || pci_ext_cfg_is_aliased(dev)) goto fail; return PCI_CFG_SPACE_EXP_SIZE; |