diff options
| -rw-r--r-- | arch/mips/bcm47xx/prom.c | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c index 0fa646c5a844..f6e9063cc4c2 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); } |