This adds a simple way to get the root port a given device is connected to.
Signed-off-by: Lucas Stach <[email protected]> --- v2: new patch in v2 v3: rename to pci_find_rootport to fit better with other API v4: - rename to make it obvious that this function is PCIe specific - fixes wrong assumption about what is a root bus in the presence virtual buses --- drivers/pci/search.c | 20 ++++++++++++++++++++ include/linux/pci.h | 1 + 2 files changed, 21 insertions(+) diff --git a/drivers/pci/search.c b/drivers/pci/search.c index a20ce7d5e2a7..d7c599103ae1 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -384,3 +384,23 @@ int pci_dev_present(const struct pci_device_id *ids) return 0; } EXPORT_SYMBOL(pci_dev_present); + +/** + * pcie_find_root_port - Returns the root port the given device is connected to. + * @dev: PCI device for which the root port should be found. + */ +struct pci_dev *pcie_find_root_port(struct pci_dev *dev) +{ + struct pci_bus *bus = dev->bus; + + /* if this device is located on the root bus, it is a root port */ + if (pci_is_root_bus(bus)) + return dev; + + /* walk up the PCI hierarchy to the first level below the root */ + while (bus->parent && bus->parent->parent) + bus = bus->parent; + + return bus->self; +} +EXPORT_SYMBOL(pcie_find_root_port); diff --git a/include/linux/pci.h b/include/linux/pci.h index 211e9da8a7d7..308c71081034 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -844,6 +844,7 @@ static inline struct pci_dev *pci_get_bus_and_slot(unsigned int bus, } struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from); int pci_dev_present(const struct pci_device_id *ids); +struct pci_dev *pcie_find_root_port(struct pci_dev *dev); int pci_bus_read_config_byte(struct pci_bus *bus, unsigned int devfn, int where, u8 *val); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
