Diffstat (limited to 'arch/arm/kernel/bios32.c')
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
@@ -374,16 +374,29 @@ EXPORT_SYMBOL(pcibios_fixup_bus);
- * 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;
slot = sys->swizzle(dev, pin);
+ slot = pci_common_swizzle(dev, pin);
printk("PCI: %s swizzling pin %d => pin %d slot %d\n",