common/env_eeprom.c

   1 /*
   2  * (C) Copyright 2000-2002
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * (C) Copyright 2001 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   6  * Andreas Heppel <aheppel@sysgo.de>
   7
   8  * See file CREDITS for list of people who contributed to this
   9  * project.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of
  14  * the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  24  * MA 02111-1307 USA
  25  */
  26
  27 #include <common.h>
  28
  29 #if defined(CFG_ENV_IS_IN_EEPROM) /* Environment is in EEPROM */
  30
  31 #include <command.h>
  32 #include <environment.h>
  33 #include <linux/stddef.h>
  34
  35 env_t *env_ptr = NULL;
  36
  37 char * env_name_spec = "EEPROM";
  38
  39 extern uchar (*env_get_char)(int);
  40 extern uchar env_get_char_memory (int index);
  41
  42
  43 uchar env_get_char_spec (int index)
  44 {
  45         uchar c;
  46
  47         eeprom_read (CFG_DEF_EEPROM_ADDR,
  48                      CFG_ENV_OFFSET+index+offsetof(env_t,data),
  49                      &c, 1);
  50
  51         return (c);
  52 }
  53
  54 void env_relocate_spec (void)
  55 {
  56         eeprom_read (CFG_DEF_EEPROM_ADDR,
  57                      CFG_ENV_OFFSET,
  58                      (uchar*)env_ptr,
  59                      CFG_ENV_SIZE);
  60 }
  61
  62 int saveenv(void)
  63 {
  64         return eeprom_write (CFG_DEF_EEPROM_ADDR,
  65                              CFG_ENV_OFFSET,
  66                              (uchar *)env_ptr,
  67                              CFG_ENV_SIZE);
  68 }
  69
  70 /************************************************************************
  71  * Initialize Environment use
  72  *
  73  * We are still running from ROM, so data use is limited
  74  * Use a (moderately small) buffer on the stack
  75  */
  76 int env_init(void)
  77 {
  78         DECLARE_GLOBAL_DATA_PTR;
  79
  80         ulong crc, len, new;
  81         unsigned off;
  82         uchar buf[64];
  83
  84         eeprom_init (); /* prepare for EEPROM read/write */
  85
  86         /* read old CRC */
  87         eeprom_read (CFG_DEF_EEPROM_ADDR,
  88                      CFG_ENV_OFFSET+offsetof(env_t,crc),
  89                      (uchar *)&crc, sizeof(ulong));
  90
  91         new = 0;
  92         len = ENV_SIZE;
  93         off = offsetof(env_t,data);
  94         while (len > 0) {
  95                 int n = (len > sizeof(buf)) ? sizeof(buf) : len;
  96
  97                 eeprom_read (CFG_DEF_EEPROM_ADDR, CFG_ENV_OFFSET+off, buf, n);
  98                 new = crc32 (new, buf, n);
  99                 len -= n;
 100                 off += n;
 101         }
 102
 103         if (crc == new) {
 104                 gd->env_addr  = offsetof(env_t,data);
 105                 gd->env_valid = 1;
 106         } else {
 107                 gd->env_addr  = 0;
 108                 gd->env_valid = 0;
 109         }
 110
 111         return (0);
 112 }
 113
 114 #endif /* CFG_ENV_IS_IN_EEPROM */