[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>

4 files changed, 22 insertions, 26 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);
 }
 
 
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 465e7435efbc..0af3fc1bdcc9 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -304,18 +304,21 @@ struct seq_operations cpuinfo_op = {
 void __init check_for_initrd(void)
 {
 #ifdef CONFIG_BLK_DEV_INITRD
-        const unsigned long *prop;
+        const unsigned int *prop;
+        int len;
 
         DBG(" -> check_for_initrd()\n");
 
         if (of_chosen) {
-                prop = get_property(of_chosen, "linux,initrd-start", NULL);
+                prop = get_property(of_chosen, "linux,initrd-start", &len);
                 if (prop != NULL) {
-                        initrd_start = (unsigned long)__va(*prop);
+                        initrd_start = (unsigned long)
+                                __va(of_read_ulong(prop, len / 4));
                         prop = get_property(of_chosen,
-                                        "linux,initrd-end", NULL);
+                                        "linux,initrd-end", &len);
                         if (prop != NULL) {
-                                initrd_end = (unsigned long)__va(*prop);
+                                initrd_end = (unsigned long)
+                                        __va(of_read_ulong(prop, len / 4));
                                 initrd_below_start_ok = 1;
                         } else
                                 initrd_start = 0;
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index b9a2061cfdb7..7a3c3f791ade 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -870,9 +870,7 @@ static int __init get_freq(char *name, int cells, unsigned long *val)
                 fp = get_property(cpu, name, NULL);
                 if (fp) {
                         found = 1;
-                        *val = 0;
-                        while (cells--)
-                                *val = (*val << 32) | *fp++;
+                        *val = of_read_ulong(fp, cells);
                 }
 
                 of_node_put(cpu);
diff --git a/include/asm-powerpc/prom.h b/include/asm-powerpc/prom.h
index c15e66a2e681..524629769336 100644
--- a/include/asm-powerpc/prom.h
+++ b/include/asm-powerpc/prom.h
@@ -197,7 +197,7 @@ extern int release_OF_resource(struct device_node* node, int index);
  */
 
 
-/* Helper to read a big number */
+/* Helper to read a big number; size is in cells (not bytes) */
 static inline u64 of_read_number(const u32 *cell, int size)
 {
         u64 r = 0;
@@ -206,6 +206,16 @@ static inline u64 of_read_number(const u32 *cell, int size)
         return r;
 }
 
+/* Like of_read_number, but we want an unsigned long result */
+#ifdef CONFIG_PPC32
+static inline unsigned long of_read_ulong(const u32 *cell, int size)
+{
+        return cell[size-1];
+}
+#else
+#define of_read_ulong(cell, size)       of_read_number(cell, size)
+#endif
+
 /* Translate an OF address block into a CPU physical address
  */
 #define OF_BAD_ADDR     ((u64)-1)