diff options
| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2017-11-10 19:52:30 +0200 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2017-12-18 23:05:52 -0600 |
| commit | 9d987eba8ed794b9fcf0d08cf1b312d2ece598de (patch) | |
| tree | 4ca8f71fa0dd8293cabaac39d378d0a91c558cc1 /arch | |
| parent | dd1ea5763e65c69983697dc97ea9d6e3cb9df922 (diff) | |
powerpc/pci: Unroll two pass loop when scanning bridges
The current scanning code is really hard to understand because it calls the
same function in a loop where pass value is changed without any comments
explaining it:
for (pass = 0; pass < 2; pass++)
for_each_pci_bridge(dev, bus)
max = pci_scan_bridge(bus, dev, max, pass);
Unfamiliar reader cannot tell easily what is the purpose of this loop
without looking at internals of pci_scan_bridge().
In order to make this bit easier to understand, open-code the loop in
pci_scan_child_bus() and pci_hp_add_bridge() with added comments.
No functional changes intended.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/pci-hotplug.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/arch/powerpc/kernel/pci-hotplug.c b/arch/powerpc/kernel/pci-hotplug.c index 741f47295188..cf47b1aec4c2 100644 --- a/arch/powerpc/kernel/pci-hotplug.c +++ b/arch/powerpc/kernel/pci-hotplug.c @@ -104,7 +104,7 @@ EXPORT_SYMBOL_GPL(pci_hp_remove_devices); */ void pci_hp_add_devices(struct pci_bus *bus) { - int slotno, mode, pass, max; + int slotno, mode, max; struct pci_dev *dev; struct pci_controller *phb; struct device_node *dn = pci_bus_to_OF_node(bus); @@ -133,10 +133,17 @@ void pci_hp_add_devices(struct pci_bus *bus) pci_scan_slot(bus, PCI_DEVFN(slotno, 0)); pcibios_setup_bus_devices(bus); max = bus->busn_res.start; - for (pass = 0; pass < 2; pass++) { - for_each_pci_bridge(dev, bus) - max = pci_scan_bridge(bus, dev, max, pass); - } + /* + * Scan bridges that are already configured. We don't touch + * them unless they are misconfigured (which will be done in + * the second scan below). + */ + for_each_pci_bridge(dev, bus) + max = pci_scan_bridge(bus, dev, max, 0); + + /* Scan bridges that need to be reconfigured */ + for_each_pci_bridge(dev, bus) + max = pci_scan_bridge(bus, dev, max, 1); } pcibios_finish_adding_to_bus(bus); } |