arch/mips/ddb5xxx/common/prom.c

   1 /*
   2  * Copyright 2001 MontaVista Software Inc.
   3  * Author: jsun@mvista.com or jsun@junsun.net
   4  *
   5  * This program is free software; you can redistribute  it and/or modify it
   6  * under  the terms of  the GNU General  Public License as published by the
   7  * Free Software Foundation;  either version 2 of the  License, or (at your
   8  * option) any later version.
   9  */
  10 #include <linux/init.h>
  11 #include <linux/mm.h>
  12 #include <linux/sched.h>
  13 #include <linux/bootmem.h>
  14
  15 #include <asm/addrspace.h>
  16 #include <asm/bootinfo.h>
  17 #include <asm/ddb5xxx/ddb5xxx.h>
  18 #include <asm/debug.h>
  19
  20 const char *get_system_type(void)
  21 {
  22         switch (mips_machtype) {
  23         case MACH_NEC_DDB5477:          return "NEC DDB Vrc-5477";
  24         case MACH_NEC_ROCKHOPPER:       return "NEC Rockhopper";
  25         case MACH_NEC_ROCKHOPPERII:     return "NEC RockhopperII";
  26         default:                        return "Unknown NEC board";
  27         }
  28 }
  29
  30 #if defined(CONFIG_DDB5477)
  31 void ddb5477_runtime_detection(void);
  32 #endif
  33
  34 /* [jsun@junsun.net] PMON passes arguments in C main() style */
  35 void __init prom_init(void)
  36 {
  37         int argc = fw_arg0;
  38         char **arg = (char**) fw_arg1;
  39         int i;
  40
  41         /* if user passes kernel args, ignore the default one */
  42         if (argc > 1)
  43                 arcs_cmdline[0] = '\0';
  44
  45         /* arg[0] is "g", the rest is boot parameters */
  46         for (i = 1; i < argc; i++) {
  47                 if (strlen(arcs_cmdline) + strlen(arg[i] + 1)
  48                     >= sizeof(arcs_cmdline))
  49                         break;
  50                 strcat(arcs_cmdline, arg[i]);
  51                 strcat(arcs_cmdline, " ");
  52         }
  53
  54         mips_machgroup = MACH_GROUP_NEC_DDB;
  55
  56 #if defined(CONFIG_DDB5477)
  57         ddb5477_runtime_detection();
  58         add_memory_region(0, board_ram_size, BOOT_MEM_RAM);
  59 #endif
  60 }
  61
  62 unsigned long __init prom_free_prom_memory(void)
  63 {
  64         return 0;
  65 }
  66
  67 #if defined(CONFIG_DDB5477)
  68
  69 #define DEFAULT_LCS1_BASE 0x19000000
  70 #define TESTVAL1 'K'
  71 #define TESTVAL2 'S'
  72
  73 int board_ram_size;
  74 void ddb5477_runtime_detection(void)
  75 {
  76         volatile char *test_offset;
  77         char saved_test_byte;
  78
  79         /* Determine if this is a DDB5477 board, or a BSB-VR0300
  80            base board.  We can tell by checking for the location of
  81            the NVRAM.  It lives at the beginning of LCS1 on the DDB5477,
  82            and the beginning of LCS1 on the BSB-VR0300 is flash memory.
  83            The first 2K of the NVRAM are reserved, so don't we'll poke
  84            around just after that.
  85          */
  86
  87         /* We can only use the PCI bus to distinquish between
  88            the Rockhopper and RockhopperII backplanes and this must
  89            wait until ddb5477_board_init() in setup.c after the 5477
  90            is initialized.  So, until then handle
  91            both Rockhopper and RockhopperII backplanes as Rockhopper 1
  92          */
  93
  94         test_offset = (char *)KSEG1ADDR(DEFAULT_LCS1_BASE + 0x800);
  95         saved_test_byte = *test_offset;
  96
  97         *test_offset = TESTVAL1;
  98         if (*test_offset != TESTVAL1) {
  99                 /* We couldn't set our test value, so it must not be NVRAM,
 100                    so it's a BSB_VR0300 */
 101                 mips_machtype = MACH_NEC_ROCKHOPPER;
 102         } else {
 103                 /* We may have gotten lucky, and the TESTVAL1 was already
 104                    stored at the test location, so we must check a second
 105                    test value */
 106                 *test_offset = TESTVAL2;
 107                 if (*test_offset != TESTVAL2) {
 108                         /* OK, we couldn't set this value either, so it must
 109                            definately be a BSB_VR0300 */
 110                         mips_machtype = MACH_NEC_ROCKHOPPER;
 111                 } else {
 112                         /* We could change the value twice, so it must be
 113                         NVRAM, so it's a DDB_VRC5477 */
 114                         mips_machtype = MACH_NEC_DDB5477;
 115                 }
 116         }
 117         /* Restore the original byte */
 118         *test_offset = saved_test_byte;
 119
 120         /* before we know a better way, we will trust PMON for getting
 121          * RAM size
 122          */
 123         board_ram_size = 1 << (36 - (ddb_in32(DDB_SDRAM0) & 0xf));
 124
 125         db_run(printk("DDB run-time detection : %s, %d MB RAM\n",
 126                                 mips_machtype == MACH_NEC_DDB5477 ?
 127                                 "DDB5477" : "Rockhopper",
 128                                 board_ram_size >> 20));
 129
 130         /* we can't handle ram size > 128 MB */
 131         db_assert(board_ram_size <= (128 << 20));
 132 }
 133 #endif