diff options
-rw-r--r-- | drivers/pci/probe.c | 52 | ||||
-rw-r--r-- | include/linux/pci.h | 1 |
2 files changed, 53 insertions, 0 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index ac91b6fd0bcd..dcc41de1c2c8 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -882,6 +882,45 @@ free: return err; } +static bool pci_bridge_child_ext_cfg_accessible(struct pci_dev *bridge) +{ + int pos; + u32 status; + + /* + * If extended config space isn't accessible on a bridge's primary + * bus, we certainly can't access it on the secondary bus. + */ + if (bridge->bus->bus_flags & PCI_BUS_FLAGS_NO_EXTCFG) + return false; + + /* + * PCIe Root Ports and switch ports are PCIe on both sides, so if + * extended config space is accessible on the primary, it's also + * accessible on the secondary. + */ + if (pci_is_pcie(bridge) && + (pci_pcie_type(bridge) == PCI_EXP_TYPE_ROOT_PORT || + pci_pcie_type(bridge) == PCI_EXP_TYPE_UPSTREAM || + pci_pcie_type(bridge) == PCI_EXP_TYPE_DOWNSTREAM)) + return true; + + /* + * For the other bridge types: + * - PCI-to-PCI bridges + * - PCIe-to-PCI/PCI-X forward bridges + * - PCI/PCI-X-to-PCIe reverse bridges + * extended config space on the secondary side is only accessible + * if the bridge supports PCI-X Mode 2. + */ + pos = pci_find_capability(bridge, PCI_CAP_ID_PCIX); + if (!pos) + return false; + + pci_read_config_dword(bridge, pos + PCI_X_STATUS, &status); + return status & (PCI_X_STATUS_266MHZ | PCI_X_STATUS_533MHZ); +} + static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent, struct pci_dev *bridge, int busnr) { @@ -923,6 +962,16 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent, pci_set_bus_of_node(child); pci_set_bus_speed(child); + /* + * Check whether extended config space is accessible on the child + * bus. Note that we currently assume it is always accessible on + * the root bus. + */ + if (!pci_bridge_child_ext_cfg_accessible(bridge)) { + child->bus_flags |= PCI_BUS_FLAGS_NO_EXTCFG; + pci_info(child, "extended config space not accessible\n"); + } + /* Set up default resource pointers and names */ for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) { child->resource[i] = &bridge->resource[PCI_BRIDGE_RESOURCES+i]; @@ -1393,6 +1442,9 @@ int pci_cfg_space_size(struct pci_dev *dev) u32 status; u16 class; + if (dev->bus->bus_flags & PCI_BUS_FLAGS_NO_EXTCFG) + return PCI_CFG_SPACE_SIZE; + class = dev->class >> 8; if (class == PCI_CLASS_BRIDGE_HOST) return pci_cfg_space_size_ext(dev); diff --git a/include/linux/pci.h b/include/linux/pci.h index 73178a2fcee0..5eb97e198325 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -217,6 +217,7 @@ enum pci_bus_flags { PCI_BUS_FLAGS_NO_MSI = (__force pci_bus_flags_t) 1, PCI_BUS_FLAGS_NO_MMRBC = (__force pci_bus_flags_t) 2, PCI_BUS_FLAGS_NO_AERSID = (__force pci_bus_flags_t) 4, + PCI_BUS_FLAGS_NO_EXTCFG = (__force pci_bus_flags_t) 8, }; /* Values from Link Status register, PCIe r3.1, sec 7.8.8 */ |