From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:35238 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752282AbbAMT5b (ORCPT ); Tue, 13 Jan 2015 14:57:31 -0500 From: Lucas Stach To: Thierry Reding , Bjorn Helgaas Cc: linux-tegra@vger.kernel.org, linux-pci@vger.kernel.org Subject: [PATCH v3 1/2] PCI: add helper function to find root port for device Date: Tue, 13 Jan 2015 20:57:27 +0100 Message-Id: <1421179048-25370-1-git-send-email-l.stach@pengutronix.de> Sender: linux-pci-owner@vger.kernel.org List-ID: This adds a simple way to get the root port a given device is connected to. Signed-off-by: Lucas Stach --- v2: new patch in v2 v3: rename to pci_find_rootport to fit better with other API --- 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..7254f126096d 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); + +/** + * pci_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 *pci_find_root_port(struct pci_dev *dev) +{ + struct pci_bus *bus = dev->bus; + + /* If there is no bridge on the bus the passed device is a root port. */ + if (!bus->self) + return dev; + + /* Walk up the PCI hierarchy to the first level below the root. */ + while (bus->parent && bus->parent->self) + bus = bus->parent; + + return bus->self; +} +EXPORT_SYMBOL(pci_find_root_port); diff --git a/include/linux/pci.h b/include/linux/pci.h index 360a966a97a5..f4321c5ba653 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 *pci_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