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--- a/arch/mips/bcm47xx/prom.c
+++ b/arch/mips/bcm47xx/prom.c
@@ -126,6 +126,7 @@ static __init void prom_init_cmdline(voi
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("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);
}
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