target/linux/brcm-2.4/files/arch/mips/bcm947xx/prom.c

   1 /*
   2  * Early initialization code for BCM94710 boards
   3  *
   4  * Copyright 2004, Broadcom Corporation
   5  * All Rights Reserved.
   6  *
   7  * THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY
   8  * KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM
   9  * SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
  10  * FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.
  11  *
  12  */
  13
  14 #include <linux/config.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/types.h>
  18 #include <asm/bootinfo.h>
  19
  20 void __init
  21 prom_init(int argc, const char **argv)
  22 {
  23         unsigned long mem;
  24         unsigned long max;
  25
  26         mips_machgroup = MACH_GROUP_BRCM;
  27         mips_machtype = MACH_BCM947XX;
  28
  29         /* Figure out memory size by finding aliases
  30          *
  31          * BCM47XX uses 128MB for addressing the ram, if the system contains
  32          * less that that amount of ram it remaps the ram more often into the
  33          * available space.
  34          * Accessing memory after 128MB will cause an exception.
  35          * max contains the biggest possible address supported by the platform.
  36          * If the method wants to try something above we assume 128MB ram.
  37          */
  38         max = ((unsigned long)(prom_init) | ((128 << 20) - 1));
  39         for (mem = (1 << 20); mem < (128 << 20); mem += (1 << 20)) {
  40                 if (((unsigned long)(prom_init) + mem) > max) {
  41                         mem = (128 << 20);
  42                         printk("assume 128MB RAM\n");
  43                         break;
  44                 }
  45                 if (*(unsigned long *)((unsigned long)(prom_init) + mem) ==
  46                     *(unsigned long *)(prom_init))
  47                         break;
  48         }
  49
  50         add_memory_region(0, mem, BOOT_MEM_RAM);
  51 }
  52
  53 void __init
  54 prom_free_prom_memory(void)
  55 {
  56 }