| 1 | --- a/arch/mips/bcm47xx/prom.c |
| 2 | +++ b/arch/mips/bcm47xx/prom.c |
| 3 | @@ -126,6 +126,7 @@ static __init void prom_init_cmdline(voi |
| 4 | static __init void prom_init_mem(void) |
| 5 | { |
| 6 | unsigned long mem; |
| 7 | + unsigned long max; |
| 8 | |
| 9 | /* Figure out memory size by finding aliases. |
| 10 | * |
| 11 | @@ -134,8 +135,21 @@ static __init void prom_init_mem(void) |
| 12 | * want to reuse the memory used by CFE (around 4MB). That means cfe_* |
| 13 | * functions stop to work at some point during the boot, we should only |
| 14 | * call them at the beginning of the boot. |
| 15 | + * |
| 16 | + * BCM47XX uses 128MB for addressing the ram, if the system contains |
| 17 | + * less that that amount of ram it remaps the ram more often into the |
| 18 | + * available space. |
| 19 | + * Accessing memory after 128MB will cause an exception. |
| 20 | + * max contains the biggest possible address supported by the platform. |
| 21 | + * If the method wants to try something above we assume 128MB ram. |
| 22 | */ |
| 23 | + max = ((unsigned long)(prom_init) | ((128 << 20) - 1)); |
| 24 | for (mem = (1 << 20); mem < (128 << 20); mem += (1 << 20)) { |
| 25 | + if (((unsigned long)(prom_init) + mem) > max) { |
| 26 | + mem = (128 << 20); |
| 27 | + printk("assume 128MB RAM\n"); |
| 28 | + break; |
| 29 | + } |
| 30 | if (*(unsigned long *)((unsigned long)(prom_init) + mem) == |
| 31 | *(unsigned long *)(prom_init)) |
| 32 | break; |
| 33 | |
