ARM: PCI: get rid of pci_std_swizzle()

Most PCI implementations use the standard PCI swizzle function, which
handles the well defined behaviour of PCI-to-PCI bridges which can be
found on cards (eg, four port ethernet cards.)

Rather than having almost every platform specify the standard swizzle
function, make this the default when no swizzle function is supplied.
Therefore, a swizzle function only needs to be provided when there is
something exceptional which needs to be handled.

This gets rid of the swizzle initializer from 47 files, and leaves us
with just two platforms specifying a swizzle function: ARM Integrator
and Chalice CATS.

Acked-by: Krzysztof Hałasa <khc@pm.waw.pl>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 16 insertions, 3 deletions

diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
index e17dd25..d22e351 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",