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path: root/arch/sh/drivers/pci/fixups-cayman.c
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Diffstat (limited to 'arch/sh/drivers/pci/fixups-cayman.c')
-rw-r--r--arch/sh/drivers/pci/fixups-cayman.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/arch/sh/drivers/pci/fixups-cayman.c b/arch/sh/drivers/pci/fixups-cayman.c
new file mode 100644
index 00000000000..b68b61d22c6
--- /dev/null
+++ b/arch/sh/drivers/pci/fixups-cayman.c
@@ -0,0 +1,77 @@
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/types.h>
+#include <cpu/irq.h>
+#include "pci-sh5.h"
+
+int __init pcibios_map_platform_irq(struct pci_dev *dev, u8 slot, u8 pin)
+{
+ int result = -1;
+
+ /* The complication here is that the PCI IRQ lines from the Cayman's 2
+ 5V slots get into the CPU via a different path from the IRQ lines
+ from the 3 3.3V slots. Thus, we have to detect whether the card's
+ interrupts go via the 5V or 3.3V path, i.e. the 'bridge swizzling'
+ at the point where we cross from 5V to 3.3V is not the normal case.
+
+ The added complication is that we don't know that the 5V slots are
+ always bus 2, because a card containing a PCI-PCI bridge may be
+ plugged into a 3.3V slot, and this changes the bus numbering.
+
+ Also, the Cayman has an intermediate PCI bus that goes a custom
+ expansion board header (and to the secondary bridge). This bus has
+ never been used in practice.
+
+ The 1ary onboard PCI-PCI bridge is device 3 on bus 0
+ The 2ary onboard PCI-PCI bridge is device 0 on the 2ary bus of
+ the 1ary bridge.
+ */
+
+ struct slot_pin {
+ int slot;
+ int pin;
+ } path[4];
+ int i=0;
+
+ while (dev->bus->number > 0) {
+
+ slot = path[i].slot = PCI_SLOT(dev->devfn);
+ pin = path[i].pin = pci_swizzle_interrupt_pin(dev, pin);
+ dev = dev->bus->self;
+ i++;
+ if (i > 3) panic("PCI path to root bus too long!\n");
+ }
+
+ slot = PCI_SLOT(dev->devfn);
+ /* This is the slot on bus 0 through which the device is eventually
+ reachable. */
+
+ /* Now work back up. */
+ if ((slot < 3) || (i == 0)) {
+ /* Bus 0 (incl. PCI-PCI bridge itself) : perform the final
+ swizzle now. */
+ result = IRQ_INTA + pci_swizzle_interrupt_pin(dev, pin) - 1;
+ } else {
+ i--;
+ slot = path[i].slot;
+ pin = path[i].pin;
+ if (slot > 0) {
+ panic("PCI expansion bus device found - not handled!\n");
+ } else {
+ if (i > 0) {
+ /* 5V slots */
+ i--;
+ slot = path[i].slot;
+ pin = path[i].pin;
+ /* 'pin' was swizzled earlier wrt slot, don't do it again. */
+ result = IRQ_P2INTA + (pin - 1);
+ } else {
+ /* IRQ for 2ary PCI-PCI bridge : unused */
+ result = -1;
+ }
+ }
+ }
+
+ return result;
+}