target/linux/brcm47xx/patches-3.6/191-MIPS-BCM47XX-ignore-last-memory-page.patch

   1 --- a/arch/mips/bcm47xx/prom.c
   2 +++ b/arch/mips/bcm47xx/prom.c
   3 @@ -27,6 +27,7 @@
   4  #include <linux/types.h>
   5  #include <linux/kernel.h>
   6  #include <linux/spinlock.h>
   7 +#include <linux/smp.h>
   8  #include <asm/bootinfo.h>
   9  #include <asm/fw/cfe/cfe_api.h>
  10  #include <asm/fw/cfe/cfe_error.h>
  11 @@ -59,6 +60,7 @@ static __init void prom_init_mem(void)
  12  {
  13         unsigned long mem;
  14         unsigned long max;
  15 +       struct cpuinfo_mips *c = &current_cpu_data;
  16
  17         /* Figure out memory size by finding aliases.
  18          *
  19 @@ -87,6 +89,14 @@ static __init void prom_init_mem(void)
  20                         break;
  21         }
  22
  23 +       /* Ignoring the last page when ddr size is 128M. Cached
  24 +        * accesses to last page is causing the processor to prefetch
  25 +        * using address above 128M stepping out of the ddr address
  26 +        * space.
  27 +        */
  28 +       if (c->cputype == CPU_74K && (mem == (128  << 20)))
  29 +               mem -= 0x1000;
  30 +
  31         add_memory_region(0, mem, BOOT_MEM_RAM);
  32  }
  33