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* [PATCH v2 1/2] PCI: add helper function to find root port for device
@ 2014-12-18 19:11 ` Lucas Stach
  0 siblings, 0 replies; 10+ messages in thread
From: Lucas Stach @ 2014-12-18 19:11 UTC (permalink / raw)
  To: Bjorn Helgaas, Thierry Reding
  Cc: Alexandre Courbot, linux-tegra-u79uwXL29TY76Z2rM5mHXA,
	linux-pci-u79uwXL29TY76Z2rM5mHXA

This adds a simple way to get the root port a given device
is connected to.

Signed-off-by: Lucas Stach <l.stach-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
v2: new patch in v2
---
 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 a81f413083e4..c3ae1c52c7cf 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -385,3 +385,23 @@ int pci_dev_present(const struct pci_device_id *ids)
 	return 0;
 }
 EXPORT_SYMBOL(pci_dev_present);
+
+/**
+ * pci_get_rootport - 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_get_rootport(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_get_rootport);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 4c8ac5fcc224..05442db50cad 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -843,6 +843,7 @@ 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_get_rootport(struct pci_dev *dev);
 
 int pci_bus_read_config_byte(struct pci_bus *bus, unsigned int devfn,
 			     int where, u8 *val);
-- 
2.1.3

^ permalink raw reply related	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2015-01-09 11:58 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-12-18 19:11 [PATCH v2 1/2] PCI: add helper function to find root port for device Lucas Stach
2014-12-18 19:11 ` Lucas Stach
     [not found] ` <1418929903-8506-1-git-send-email-l.stach-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2014-12-18 19:11   ` [PATCH v2 2/2] PCI: tegra: apply relaxed ordering fixup only on Tegra Lucas Stach
2014-12-18 19:11     ` Lucas Stach
2015-01-09 11:32     ` Thierry Reding
2015-01-09 11:45       ` Lucas Stach
2015-01-09 11:45         ` Lucas Stach
2015-01-09 11:58         ` Thierry Reding
2015-01-09 11:25   ` [PATCH v2 1/2] PCI: add helper function to find root port for device Thierry Reding
2015-01-09 11:25     ` Thierry Reding

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