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authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>2017-11-10 19:52:30 +0200
committerBjorn Helgaas <bhelgaas@google.com>2017-12-18 23:05:52 -0600
commit9d987eba8ed794b9fcf0d08cf1b312d2ece598de (patch)
tree4ca8f71fa0dd8293cabaac39d378d0a91c558cc1 /arch/powerpc/kernel/pci-hotplug.c
parentdd1ea5763e65c69983697dc97ea9d6e3cb9df922 (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/powerpc/kernel/pci-hotplug.c')
-rw-r--r--arch/powerpc/kernel/pci-hotplug.c17
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);
}