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PCI: Add pci_scan_root_bus_bridge() interface

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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>
This commit is contained in:
Lorenzo Pieralisi 2017-06-28 15:13:55 -05:00 committed by Bjorn Helgaas
parent 792abc6e2f
commit 1228c4b6c1
2 changed files with 40 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
drivers/pci/probe.c
View File

@ -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)

1
include/linux/pci.h
View File

@ -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);