1 files changed, 14 insertions, 8 deletions

diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c
index 0fa646c5a84..f6e9063cc4c 100644
--- a/arch/mips/bcm47xx/prom.c
+++ b/arch/mips/bcm47xx/prom.c
@@ -126,6 +126,7 @@ static __init void prom_init_cmdline(void)
 static __init void prom_init_mem(void)
 {
         unsigned long mem;
+        unsigned long max;
 
         /* Figure out memory size by finding aliases.
          *
@@ -134,21 +135,26 @@ static __init void prom_init_mem(void)
          * want to reuse the memory used by CFE (around 4MB). That means cfe_*
          * functions stop to work at some point during the boot, we should only
          * call them at the beginning of the boot.
+         *
+         * BCM47XX uses 128MB for addressing the ram, if the system contains
+         * less that that amount of ram it remaps the ram more often into the
+         * available space.
+         * Accessing memory after 128MB will cause an exception.
+         * max contains the biggest possible address supported by the platform.
+         * If the method wants to try something above we assume 128MB ram.
          */
+        max = ((unsigned long)(prom_init) | ((128 << 20) - 1));
         for (mem = (1 << 20); mem < (128 << 20); mem += (1 << 20)) {
+                if (((unsigned long)(prom_init) + mem) > max) {
+                        mem = (128 << 20);
+                        printk(KERN_DEBUG "assume 128MB RAM\n");
+                        break;
+                }
                 if (*(unsigned long *)((unsigned long)(prom_init) + mem) ==
                     *(unsigned long *)(prom_init))
                         break;
         }
 
-        /* Ignoring the last page when ddr size is 128M. Cached
-         * accesses to last page is causing the processor to prefetch
-         * using address above 128M stepping out of the ddr address
-         * space.
-         */
-        if (mem == 0x8000000)
-                mem -= 0x1000;
-
         add_memory_region(0, mem, BOOT_MEM_RAM);
 }