1 files changed, 25 insertions, 13 deletions

diff --git a/sim/bfin/dv-bfin_gpio2.c b/sim/bfin/dv-bfin_gpio2.c
index 0069e0d331b..a2b941956a0 100644
--- a/sim/bfin/dv-bfin_gpio2.c
+++ b/sim/bfin/dv-bfin_gpio2.c
@@ -66,22 +66,28 @@ bfin_gpio_io_write_buffer (struct hw *me, const void *source, int space,
   bu32 *value32p;
   void *valuep;
 
+  mmr_off = addr - port->base;
+
+  /* Invalid access mode is higher priority than missing register.  */
+  if (mmr_off == mmr_offset (mux))
+    {
+      if (!dv_bfin_mmr_require_32 (me, addr, nr_bytes, true))
+	return 0;
+    }
+  else
+    if (!dv_bfin_mmr_require_16 (me, addr, nr_bytes, true))
+	return 0;
+
   if (nr_bytes == 4)
     value = dv_load_4 (source);
   else
     value = dv_load_2 (source);
-  mmr_off = addr - port->base;
   valuep = (void *)((unsigned long)port + mmr_base() + mmr_off);
   value16p = valuep;
   value32p = valuep;
 
   HW_TRACE_WRITE ();
 
-  if (mmr_off == mmr_offset (mux))
-    dv_bfin_mmr_require_32 (me, addr, nr_bytes, true);
-  else
-    dv_bfin_mmr_require_16 (me, addr, nr_bytes, true);
-
   switch (mmr_off)
     {
     case mmr_offset(fer):
@@ -108,7 +114,7 @@ bfin_gpio_io_write_buffer (struct hw *me, const void *source, int space,
       break;
     default:
       dv_bfin_mmr_invalid (me, addr, nr_bytes, true);
-      break;
+      return 0;
     }
 
   /* If tweaking output pins, make sure we send updated port info.  */
@@ -148,17 +154,23 @@ bfin_gpio_io_read_buffer (struct hw *me, void *dest, int space,
   void *valuep;
 
   mmr_off = addr - port->base;
+
+  /* Invalid access mode is higher priority than missing register.  */
+  if (mmr_off == mmr_offset (mux))
+    {
+      if (!dv_bfin_mmr_require_32 (me, addr, nr_bytes, false))
+	return 0;
+    }
+  else
+    if (!dv_bfin_mmr_require_16 (me, addr, nr_bytes, false))
+      return 0;
+
   valuep = (void *)((unsigned long)port + mmr_base() + mmr_off);
   value16p = valuep;
   value32p = valuep;
 
   HW_TRACE_READ ();
 
-  if (mmr_off == mmr_offset (mux))
-    dv_bfin_mmr_require_32 (me, addr, nr_bytes, false);
-  else
-    dv_bfin_mmr_require_16 (me, addr, nr_bytes, false);
-
   switch (mmr_off)
     {
     case mmr_offset(data):
@@ -179,7 +191,7 @@ bfin_gpio_io_read_buffer (struct hw *me, void *dest, int space,
       break;
     default:
       dv_bfin_mmr_invalid (me, addr, nr_bytes, false);
-      break;
+      return 0;
     }
 
   return nr_bytes;