dm: pci: Make ranges dt property optional

If we use U-Boot as coreboot payload with a generic dts without
any ranges specified we fail in pci pre_probe and our pci bus
is not usable.

So convert decode_regions(..) into a void function and do the simple
error handling there.

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: fixed 'u-boot' in the commit message and checkpatch warning]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/pci/pci-uclass.c

@@ -810,8 +810,8 @@ error:
 	return ret;
 }
 
-static int decode_regions(struct pci_controller *hose, ofnode parent_node,
-			  ofnode node)
+static void decode_regions(struct pci_controller *hose, ofnode parent_node,
+			   ofnode node)
 {
 	int pci_addr_cells, addr_cells, size_cells;
 	int cells_per_record;
@@ -820,8 +820,11 @@ static int decode_regions(struct pci_controller *hose, ofnode parent_node,
 	int i;
 
 	prop = ofnode_get_property(node, "ranges", &len);
-	if (!prop)
-		return -EINVAL;
+	if (!prop) {
+		debug("%s: Cannot decode regions\n", __func__);
+		return;
+	}
+
 	pci_addr_cells = ofnode_read_simple_addr_cells(node);
 	addr_cells = ofnode_read_simple_addr_cells(parent_node);
 	size_cells = ofnode_read_simple_size_cells(node);
@@ -883,7 +886,7 @@ static int decode_regions(struct pci_controller *hose, ofnode parent_node,
 	bd_t *bd = gd->bd;
 
 	if (!bd)
-		return 0;
+		return;
 
 	for (i = 0; i < CONFIG_NR_DRAM_BANKS; ++i) {
 		if (bd->bi_dram[i].size) {
@@ -908,13 +911,12 @@ static int decode_regions(struct pci_controller *hose, ofnode parent_node,
 			base, size, PCI_REGION_MEM | PCI_REGION_SYS_MEMORY);
 #endif
 
-	return 0;
+	return;
 }
 
 static int pci_uclass_pre_probe(struct udevice *bus)
 {
 	struct pci_controller *hose;
-	int ret;
 
 	debug("%s, bus=%d/%s, parent=%s\n", __func__, bus->seq, bus->name,
 	      bus->parent->name);
@@ -923,12 +925,7 @@ static int pci_uclass_pre_probe(struct udevice *bus)
 	/* For bridges, use the top-level PCI controller */
 	if (!device_is_on_pci_bus(bus)) {
 		hose->ctlr = bus;
-		ret = decode_regions(hose, dev_ofnode(bus->parent),
-				     dev_ofnode(bus));
-		if (ret) {
-			debug("%s: Cannot decode regions\n", __func__);
-			return ret;
-		}
+		decode_regions(hose, dev_ofnode(bus->parent), dev_ofnode(bus));
 	} else {
 		struct pci_controller *parent_hose;