[PATCH] ARM/dt: Respect #address-cells when parsing CPUs

[Robin Murphy]

Whilst MPIDR values themselves are only 32 bits, it is still perfectly
valid for a DT to have #address-cells > 1 in the CPUs node, resulting in
the "reg" property having leading zero cell(s). In that situation, the
big-endian nature of the data conspires with the current behaviour of
just parsing the first cell to cause the kernel to think all CPUs have
ID 0, and become resoundingly unhappy as a consequence.

Take #address-cells into account when parsing CPUs so as to be correct
under any circumstances.

CC: Russell King <linux at armlinux.org.uk>
Signed-off-by: Robin Murphy <robin.murphy at arm.com>
---
 arch/arm/kernel/devtree.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index 40ecd5f514a2..7ab113c5c818 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -88,6 +88,7 @@ void __init arm_dt_init_cpu_maps(void)
 		return;
 
 	for_each_child_of_node(cpus, cpu) {
+		const u32 *cell;
 		u32 hwid;
 
 		if (of_node_cmp(cpu->type, "cpu"))
@@ -99,12 +100,14 @@ void __init arm_dt_init_cpu_maps(void)
 		 * properties is considered invalid to build the
 		 * cpu_logical_map.
 		 */
-		if (of_property_read_u32(cpu, "reg", &hwid)) {
+		cell = of_get_property(cpu, "reg", NULL);
+		if (!cell) {
 			pr_debug(" * %s missing reg property\n",
 				     cpu->full_name);
 			of_node_put(cpu);
 			return;
 		}
+		hwid = of_read_number(cell, of_n_addr_cells(cpu));
 
 		/*
 		 * 8 MSBs must be set to 0 in the DT since the reg property
-- 
2.8.1.dirty