powerpc: Make radeon 32-bit MSI quirk work on powernv

This moves the quirk itself to pci_64.c as to get built on all ppc64
platforms (the only ones with a pci_dn), factors the two implementations
of get_pdn() into a single pci_get_dn() and use the quirk to do 32-bit
MSIs on IODA based powernv platforms.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index 873050d..2e86296 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -266,3 +266,13 @@
 }
 EXPORT_SYMBOL(pcibus_to_node);
 #endif
+
+static void quirk_radeon_32bit_msi(struct pci_dev *dev)
+{
+	struct pci_dn *pdn = pci_get_pdn(dev);
+
+	if (pdn)
+		pdn->force_32bit_msi = 1;
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x68f2, quirk_radeon_32bit_msi);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0xaa68, quirk_radeon_32bit_msi);
diff --git a/arch/powerpc/kernel/pci_dn.c b/arch/powerpc/kernel/pci_dn.c
index e7af165..df03844 100644
--- a/arch/powerpc/kernel/pci_dn.c
+++ b/arch/powerpc/kernel/pci_dn.c
@@ -32,6 +32,14 @@
 #include <asm/ppc-pci.h>
 #include <asm/firmware.h>
 
+struct pci_dn *pci_get_pdn(struct pci_dev *pdev)
+{
+	struct device_node *dn = pci_device_to_OF_node(pdev);
+	if (!dn)
+		return NULL;
+	return PCI_DN(dn);
+}
+
 /*
  * Traverse_func that inits the PCI fields of the device node.
  * NOTE: this *must* be done before read/write config to the device.