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Commit 1228c4b6 authored by Lorenzo Pieralisi's avatar Lorenzo Pieralisi Committed by Bjorn Helgaas
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PCI: Add pci_scan_root_bus_bridge() interface 



The current pci_scan_root_bus() interface is made up of two main code
paths:

  - pci_create_root_bus()
  - pci_scan_child_bus()

pci_create_root_bus() is a wrapper function that allows to create a struct
pci_host_bridge structure, initialize it with the passed parameters and
register it with the kernel.

As the struct pci_host_bridge require additional struct members,
pci_create_root_bus() parameters list has grown in time, making it unwieldy
to add further parameters to it in case the struct pci_host_bridge gains
more members fields to augment its functionality.

Since PCI core code provides functions to allocate struct pci_host_bridge,
instead of forcing the pci_create_root_bus() interface to add new
parameters to cater for new struct pci_host_bridge functionality, it is
more suitable to add an interface in PCI core code to scan a PCI bus
straight from a struct pci_host_bridge created and customized by each
specific PCI host controller driver.

Add a pci_scan_root_bus_bridge() function to allow PCI host controller
drivers to create and initialize struct pci_host_bridge and scan the
resulting bus.

Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
parent 792abc6e

drivers/pci/probe.c

+39 −0
Original line number Diff line number Diff line
@@ -2426,6 +2426,45 @@ void pci_bus_release_busn_res(struct pci_bus *b) 
			res, ret ? "can not be" : "is");

}



int pci_scan_root_bus_bridge(struct pci_host_bridge *bridge)

{

	struct resource_entry *window;

	bool found = false;

	struct pci_bus *b;

	int max, bus, ret;



	if (!bridge)

		return -EINVAL;



	resource_list_for_each_entry(window, &bridge->windows)

		if (window->res->flags & IORESOURCE_BUS) {

			found = true;

			break;

		}



	ret = pci_register_host_bridge(bridge);

	if (ret < 0)

		return ret;



	b = bridge->bus;

	bus = bridge->busnr;



	if (!found) {

		dev_info(&b->dev,

		 "No busn resource found for root bus, will use [bus %02x-ff]\n",

			bus);

		pci_bus_insert_busn_res(b, bus, 255);

	}



	max = pci_scan_child_bus(b);



	if (!found)

		pci_bus_update_busn_res_end(b, max);



	return 0;

}

EXPORT_SYMBOL(pci_scan_root_bus_bridge);



struct pci_bus *pci_scan_root_bus_msi(struct device *parent, int bus,

		struct pci_ops *ops, void *sysdata,

		struct list_head *resources, struct msi_controller *msi)

include/linux/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -857,6 +857,7 @@ struct pci_bus *pci_scan_root_bus_msi(struct device *parent, int bus, 
struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,

					     struct pci_ops *ops, void *sysdata,

					     struct list_head *resources);

int pci_scan_root_bus_bridge(struct pci_host_bridge *bridge);

struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev,

				int busnr);

void pcie_update_link_speed(struct pci_bus *bus, u16 link_status);