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/config.h>
  11 #include <linux/init.h>
  12 #include <linux/mm.h>
  13 #include <linux/sched.h>
  14 #include <linux/bootmem.h>
  15
  16 #include <asm/addrspace.h>
  17 #include <asm/bootinfo.h>
  18 #include <asm/ddb5xxx/ddb5xxx.h>
  19 #include <asm/debug.h>
  20
  21 const char *get_system_type(void)
  22 {
  23         switch (mips_machtype) {
  24         case MACH_NEC_DDB5074:          return "NEC DDB Vrc-5074";
  25         case MACH_NEC_DDB5476:          return "NEC DDB Vrc-5476";
  26         case MACH_NEC_DDB5477:          return "NEC DDB Vrc-5477";
  27         case MACH_NEC_ROCKHOPPER:       return "NEC Rockhopper";
  28         case MACH_NEC_ROCKHOPPERII:     return "NEC RockhopperII";
  29         default:                        return "Unknown NEC board";
  30         }
  31 }
  32
  33 #if defined(CONFIG_DDB5477)
  34 void ddb5477_runtime_detection(void);
  35 #endif
  36
  37 /* [jsun@junsun.net] PMON passes arguments in C main() style */
  38 void __init prom_init(void)
  39 {
  40         int argc = fw_arg0;
  41         char **arg = (char**) fw_arg1;
  42         int i;
  43
  44         /* if user passes kernel args, ignore the default one */
  45         if (argc > 1)
  46                 arcs_cmdline[0] = '\0';
  47
  48         /* arg[0] is "g", the rest is boot parameters */
  49         for (i = 1; i < argc; i++) {
  50                 if (strlen(arcs_cmdline) + strlen(arg[i] + 1)
  51                     >= sizeof(arcs_cmdline))
  52                         break;
  53                 strcat(arcs_cmdline, arg[i]);
  54                 strcat(arcs_cmdline, " ");
  55         }
  56
  57         mips_machgroup = MACH_GROUP_NEC_DDB;
  58
  59 #if defined(CONFIG_DDB5074)
  60         mips_machtype = MACH_NEC_DDB5074;
  61         add_memory_region(0, DDB_SDRAM_SIZE, BOOT_MEM_RAM);
  62 #elif defined(CONFIG_DDB5476)
  63         mips_machtype = MACH_NEC_DDB5476;
  64         add_memory_region(0, DDB_SDRAM_SIZE, BOOT_MEM_RAM);
  65 #elif defined(CONFIG_DDB5477)
  66         ddb5477_runtime_detection();
  67         add_memory_region(0, board_ram_size, BOOT_MEM_RAM);
  68 #endif
  69 }
  70
  71 unsigned long __init prom_free_prom_memory(void)
  72 {
  73         return 0;
  74 }
  75
  76 #if defined(CONFIG_DDB5477)
  77
  78 #define DEFAULT_LCS1_BASE 0x19000000
  79 #define TESTVAL1 'K'
  80 #define TESTVAL2 'S'
  81
  82 int board_ram_size;
  83 void ddb5477_runtime_detection(void)
  84 {
  85         volatile char *test_offset;
  86         char saved_test_byte;
  87
  88         /* Determine if this is a DDB5477 board, or a BSB-VR0300
  89            base board.  We can tell by checking for the location of
  90            the NVRAM.  It lives at the beginning of LCS1 on the DDB5477,
  91            and the beginning of LCS1 on the BSB-VR0300 is flash memory.
  92            The first 2K of the NVRAM are reserved, so don't we'll poke
  93            around just after that.
  94          */
  95
  96         /* We can only use the PCI bus to distinquish between
  97            the Rockhopper and RockhopperII backplanes and this must
  98            wait until ddb5477_board_init() in setup.c after the 5477
  99            is initialized.  So, until then handle
 100            both Rockhopper and RockhopperII backplanes as Rockhopper 1
 101          */
 102
 103         test_offset = (char *)KSEG1ADDR(DEFAULT_LCS1_BASE + 0x800);
 104         saved_test_byte = *test_offset;
 105
 106         *test_offset = TESTVAL1;
 107         if (*test_offset != TESTVAL1) {
 108                 /* We couldn't set our test value, so it must not be NVRAM,
 109                    so it's a BSB_VR0300 */
 110                 mips_machtype = MACH_NEC_ROCKHOPPER;
 111         } else {
 112                 /* We may have gotten lucky, and the TESTVAL1 was already
 113                    stored at the test location, so we must check a second
 114                    test value */
 115                 *test_offset = TESTVAL2;
 116                 if (*test_offset != TESTVAL2) {
 117                         /* OK, we couldn't set this value either, so it must
 118                            definately be a BSB_VR0300 */
 119                         mips_machtype = MACH_NEC_ROCKHOPPER;
 120                 } else {
 121                         /* We could change the value twice, so it must be
 122                         NVRAM, so it's a DDB_VRC5477 */
 123                         mips_machtype = MACH_NEC_DDB5477;
 124                 }
 125         }
 126         /* Restore the original byte */
 127         *test_offset = saved_test_byte;
 128
 129         /* before we know a better way, we will trust PMON for getting
 130          * RAM size
 131          */
 132         board_ram_size = 1 << (36 - (ddb_in32(DDB_SDRAM0) & 0xf));
 133
 134         db_run(printk("DDB run-time detection : %s, %d MB RAM\n",
 135                                 mips_machtype == MACH_NEC_DDB5477 ?
 136                                 "DDB5477" : "Rockhopper",
 137                                 board_ram_size >> 20));
 138
 139         /* we can't handle ram size > 128 MB */
 140         db_assert(board_ram_size <= (128 << 20));
 141 }
 142 #endif