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@xxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/pci/probe.c | 38 ++++++++++++++++++++++++++++++++++++++
include/linux/pci.h | 1 +
2 files changed, 39 insertions(+)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 7e4ffc4..c7a7f72 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2412,6 +2412,44 @@ 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;
+}
+
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)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 99878a9..757779a 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -847,6 +847,7 @@ 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);
--
2.10.0
