[POWERPC] pci32: Add flags modifying the PCI code behaviour

This adds to the 32 bits PCI code some flags, replacing the old
pci_assign_all_busses global, that allow us to control various
aspects of the PCI probing, such as whether to re-assign all
resources or not, or to not try to assign anything at all.

This also adds the flag x86 already has to avoid ISA alignment
on bridges that don't have ISA forwarding enabled (no legacy
devices on the top level bus) and sets it for PowerMacs.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/pci_32.c

@@ -35,6 +35,9 @@ unsigned long isa_io_base     = 0;
 unsigned long pci_dram_offset = 0;
 int pcibios_assign_bus_offset = 1;
 
+/* Default PCI flags is 0 */
+unsigned int ppc_pci_flags;
+
 void pcibios_make_OF_bus_map(void);
 
 static void pcibios_fixup_resources(struct pci_dev* dev);
@@ -48,7 +51,7 @@ static u8* pci_to_OF_bus_map;
 /* By default, we don't re-assign bus numbers. We do this only on
  * some pmacs
  */
-int pci_assign_all_buses;
+static int pci_assign_all_buses;
 
 LIST_HEAD(hose_list);
 
@@ -174,6 +177,14 @@ void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
 }
 EXPORT_SYMBOL(pcibios_bus_to_resource);
 
+static int skip_isa_ioresource_align(struct pci_dev *dev)
+{
+	if ((ppc_pci_flags & PPC_PCI_CAN_SKIP_ISA_ALIGN) &&
+	    !(dev->bus->bridge_ctl & PCI_BRIDGE_CTL_ISA))
+		return 1;
+	return 0;
+}
+
 /*
  * We need to avoid collisions with `mirrored' VGA ports
  * and other strange ISA hardware, so we always want the
@@ -195,6 +206,8 @@ void pcibios_align_resource(void *data, struct resource *res,
 	if (res->flags & IORESOURCE_IO) {
 		resource_size_t start = res->start;
 
+		if (skip_isa_ioresource_align(dev))
+			return;
 		if (start & 0x300) {
 			start = (start + 0x3ff) & ~0x3ff;
 			res->start = start;
@@ -251,8 +264,13 @@ pcibios_allocate_bus_resources(struct list_head *bus_list)
 				continue;
 			if (bus->parent == NULL)
 				pr = (res->flags & IORESOURCE_IO)?
-					&ioport_resource: &iomem_resource;
+					&ioport_resource : &iomem_resource;
 			else {
+				/* Don't bother with non-root busses when
+				 * re-assigning all resources.
+				 */
+				if (ppc_pci_flags & PPC_PCI_REASSIGN_ALL_RSRC)
+					continue;
 				pr = pci_find_parent_resource(bus->self, res);
 				if (pr == res) {
 					/* this happens when the generic PCI
@@ -720,6 +738,9 @@ pcibios_init(void)
 
 	printk(KERN_INFO "PCI: Probing PCI hardware\n");
 
+	if (ppc_pci_flags & PPC_PCI_REASSIGN_ALL_BUS)
+		pci_assign_all_buses = 1;
+
 	/* Scan all of the recorded PCI controllers.  */
 	list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
 		if (pci_assign_all_buses)
@@ -746,13 +767,18 @@ pcibios_init(void)
 	if (ppc_md.pcibios_fixup)
 		ppc_md.pcibios_fixup();
 
-	/* Allocate and assign resources */
+	/* Allocate and assign resources. If we re-assign everything, then
+	 * we skip the allocate phase
+	 */
 	pcibios_allocate_bus_resources(&pci_root_buses);
-	pcibios_allocate_resources(0);
-	pcibios_allocate_resources(1);
-
-	DBG("PCI: Assigning unassigned resouces...\n");
-	pci_assign_unassigned_resources();
+	if (!(ppc_pci_flags & PPC_PCI_REASSIGN_ALL_RSRC)) {
+		pcibios_allocate_resources(0);
+		pcibios_allocate_resources(1);
+	}
+	if (!(ppc_pci_flags & PPC_PCI_PROBE_ONLY)) {
+		DBG("PCI: Assigning unassigned resouces...\n");
+		pci_assign_unassigned_resources();
+	}
 
 	/* Call machine dependent post-init code */
 	if (ppc_md.pcibios_after_init)