powerpc/pci: Support per-aperture memory offset

The PCI core supports an offset per aperture nowadays but our arch
code still has a single offset per host bridge representing the
difference betwen CPU memory addresses and PCI MMIO addresses.

This is a problem as new machines and hypervisor versions are
coming out where the 64-bit windows will have a different offset
(basically mapped 1:1) from the 32-bit windows.

This fixes it by using separate offsets. In the long run, we probably
want to get rid of that intermediary struct pci_controller and have
those directly stored into the pci_host_bridge as they are parsed
but this will be a more invasive change.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 97b08fc..1da578b 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -915,11 +915,14 @@
 				index++;
 			}
 		} else if (res->flags & IORESOURCE_MEM) {
+			/* WARNING: Assumes M32 is mem region 0 in PHB. We need to
+			 * harden that algorithm when we start supporting M64
+			 */
 			region.start = res->start -
-				       hose->pci_mem_offset -
+				       hose->mem_offset[0] -
 				       phb->ioda.m32_pci_base;
 			region.end   = res->end -
-				       hose->pci_mem_offset -
+				       hose->mem_offset[0] -
 				       phb->ioda.m32_pci_base;
 			index = region.start / phb->ioda.m32_segsize;
 
@@ -1115,8 +1118,7 @@
 	phb->ioda.m32_size += 0x10000;
 
 	phb->ioda.m32_segsize = phb->ioda.m32_size / phb->ioda.total_pe;
-	phb->ioda.m32_pci_base = hose->mem_resources[0].start -
-		hose->pci_mem_offset;
+	phb->ioda.m32_pci_base = hose->mem_resources[0].start - hose->mem_offset[0];
 	phb->ioda.io_size = hose->pci_io_size;
 	phb->ioda.io_segsize = phb->ioda.io_size / phb->ioda.total_pe;
 	phb->ioda.io_pci_base = 0; /* XXX calculate this ? */