diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c index 562369e6221d..ffdde6711484 100644 --- a/drivers/pci/controller/pci-tegra.c +++ b/drivers/pci/controller/pci-tegra.c @@ -6,7 +6,7 @@ * Author: Mike Rapoport * * Based on NVIDIA PCIe driver - * Copyright (c) 2008-2009, NVIDIA Corporation. + * Copyright (c) 2008-2020, NVIDIA Corporation. * * Bits taken from arch/arm/mach-dove/pcie.c * @@ -402,6 +402,14 @@ static inline u32 pads_readl(struct tegra_pcie *pcie, unsigned long offset) return readl(pcie->pads + offset); } +static bool tegra_pcie_link_up(struct tegra_pcie_port *port) +{ + u32 value; + + value = readl(port->base + RP_LINK_CONTROL_STATUS); + return !!(value & RP_LINK_CONTROL_STATUS_DL_LINK_ACTIVE); +} + /* * The configuration space mapping on Tegra is somewhat similar to the ECAM * defined by PCIe. However it deviates a bit in how the 4 bits for extended @@ -467,20 +475,50 @@ static void __iomem *tegra_pcie_map_bus(struct pci_bus *bus, static int tegra_pcie_config_read(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *value) { + struct tegra_pcie *pcie = bus->sysdata; + struct pci_dev *bridge; + struct tegra_pcie_port *port; + if (bus->number == 0) return pci_generic_config_read32(bus, devfn, where, size, value); + bridge = pcie_find_root_port(bus->self); + + list_for_each_entry(port, &pcie->ports, list) + if (port->index + 1 == PCI_SLOT(bridge->devfn)) + break; + + /* If there is no link, then there is no device */ + if (!tegra_pcie_link_up(port)) { + *value = 0xffffffff; + return PCIBIOS_DEVICE_NOT_FOUND; + } + return pci_generic_config_read(bus, devfn, where, size, value); } static int tegra_pcie_config_write(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 value) { + struct tegra_pcie *pcie = bus->sysdata; + struct tegra_pcie_port *port; + struct pci_dev *bridge; + if (bus->number == 0) return pci_generic_config_write32(bus, devfn, where, size, value); + bridge = pcie_find_root_port(bus->self); + + list_for_each_entry(port, &pcie->ports, list) + if (port->index + 1 == PCI_SLOT(bridge->devfn)) + break; + + /* If there is no link, then there is no device */ + if (!tegra_pcie_link_up(port)) + return PCIBIOS_DEVICE_NOT_FOUND; + return pci_generic_config_write(bus, devfn, where, size, value); }