1 files changed, 31 insertions, 3 deletions

diff --git a/arch/sparc/kernel/of_device.c b/arch/sparc/kernel/of_device.c
index 5a2faad5d043..97bf87e8cdde 100644
--- a/arch/sparc/kernel/of_device.c
+++ b/arch/sparc/kernel/of_device.c
@@ -596,14 +596,41 @@ static struct of_device * __init scan_one_device(struct device_node *dp,
                 static int pil_to_sbus[] = {
                         0, 0, 1, 2, 0, 3, 0, 4, 0, 5, 0, 6, 0, 7, 0, 0,
                 };
-                struct device_node *busp = dp->parent;
+                struct device_node *io_unit, *sbi = dp->parent;
                 struct linux_prom_registers *regs;
-                int board = of_getintprop_default(busp, "board#", 0);
-                int slot;
+                int board, slot;
+
+                while (sbi) {
+                        if (!strcmp(sbi->name, "sbi"))
+                                break;
+
+                        sbi = sbi->parent;
+                }
+                if (!sbi)
+                        goto build_resources;
 
                 regs = of_get_property(dp, "reg", NULL);
+                if (!regs)
+                        goto build_resources;
+
                 slot = regs->which_io;
 
+                /* If SBI's parent is not io-unit or the io-unit lacks
+                 * a "board#" property, something is very wrong.
+                 */
+                if (!sbi->parent || strcmp(sbi->parent->name, "io-unit")) {
+                        printk("%s: Error, parent is not io-unit.\n",
+                               sbi->full_name);
+                        goto build_resources;
+                }
+                io_unit = sbi->parent;
+                board = of_getintprop_default(io_unit, "board#", -1);
+                if (board == -1) {
+                        printk("%s: Error, lacks board# property.\n",
+                               io_unit->full_name);
+                        goto build_resources;
+                }
+
                 for (i = 0; i < op->num_irqs; i++) {
                         int this_irq = op->irqs[i];
                         int sbusl = pil_to_sbus[this_irq];
@@ -617,6 +644,7 @@ static struct of_device * __init scan_one_device(struct device_node *dp,
                 }
         }
 
+build_resources:
         build_device_resources(op, parent);
 
         op->dev.parent = parent;