[POWERPC] Define of_read_ulong helper

There are various places where we want to extract an unsigned long
value from a device-tree property that can be 1 or 2 cells in length.
This replaces some open-coded calculations, and one place where we
assumed without checking that properties were the length we wanted,
with a little of_read_ulong() helper.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2 insertions, 17 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index bf2005b2feb6..eb913f80bfb1 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -757,24 +757,9 @@ static int __init early_init_dt_scan_root(unsigned long node,
 static unsigned long __init dt_mem_next_cell(int s, cell_t **cellp)
 {
 	cell_t *p = *cellp;
-	unsigned long r;
 
-	/* Ignore more than 2 cells */
-	while (s > sizeof(unsigned long) / 4) {
-		p++;
-		s--;
-	}
-	r = *p++;
-#ifdef CONFIG_PPC64
-	if (s > 1) {
-		r <<= 32;
-		r |= *(p++);
-		s--;
-	}
-#endif
-
-	*cellp = p;
-	return r;
+	*cellp = p + s;
+	return of_read_ulong(p, s);
 }