diff options
Diffstat (limited to 'arch/arm/kernel/bios32.c')
| -rw-r--r-- | arch/arm/kernel/bios32.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c index e17dd2591b26..d22e35168e88 100644 --- a/arch/arm/kernel/bios32.c +++ b/arch/arm/kernel/bios32.c @@ -374,16 +374,29 @@ EXPORT_SYMBOL(pcibios_fixup_bus); #endif /* - * Swizzle the device pin each time we cross a bridge. - * This might update pin and returns the slot number. + * Swizzle the device pin each time we cross a bridge. If a platform does + * not provide a swizzle function, we perform the standard PCI swizzling. + * + * The default swizzling walks up the bus tree one level at a time, applying + * the standard swizzle function at each step, stopping when it finds the PCI + * root bus. This will return the slot number of the bridge device on the + * root bus and the interrupt pin on that device which should correspond + * with the downstream device interrupt. + * + * Platforms may override this, in which case the slot and pin returned + * depend entirely on the platform code. However, please note that the + * PCI standard swizzle is implemented on plug-in cards and Cardbus based + * PCI extenders, so it can not be ignored. */ static u8 __devinit pcibios_swizzle(struct pci_dev *dev, u8 *pin) { struct pci_sys_data *sys = dev->sysdata; - int slot = 0, oldpin = *pin; + int slot, oldpin = *pin; if (sys->swizzle) slot = sys->swizzle(dev, pin); + else + slot = pci_common_swizzle(dev, pin); if (debug_pci) printk("PCI: %s swizzling pin %d => pin %d slot %d\n", |