PCI: Add pci_scan_root_bus_bridge() interface (1228c4b6) · Commits · 戴 / test

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:

Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by:

Bjorn Helgaas <bhelgaas@google.com> Cc: Arnd Bergmann <arnd@arndb.de>

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);

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