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 #include <command.h>
  29 #include <environment.h>
  30 #include <linux/stddef.h>
  31
  32 DECLARE_GLOBAL_DATA_PTR;
  33
  34 env_t *env_ptr = NULL;
  35
  36 char * env_name_spec = "EEPROM";
  37
  38 uchar env_get_char_spec (int index)
  39 {
  40         uchar c;
  41
  42         eeprom_read (CONFIG_SYS_DEF_EEPROM_ADDR,
  43                      CONFIG_ENV_OFFSET+index+offsetof(env_t,data),
  44                      &c, 1);
  45
  46         return (c);
  47 }
  48
  49 void env_relocate_spec (void)
  50 {
  51         eeprom_read (CONFIG_SYS_DEF_EEPROM_ADDR,
  52                      CONFIG_ENV_OFFSET,
  53                      (uchar*)env_ptr,
  54                      CONFIG_ENV_SIZE);
  55 }
  56
  57 int saveenv(void)
  58 {
  59         return eeprom_write (CONFIG_SYS_DEF_EEPROM_ADDR,
  60                              CONFIG_ENV_OFFSET,
  61                              (uchar *)env_ptr,
  62                              CONFIG_ENV_SIZE);
  63 }
  64
  65 /************************************************************************
  66  * Initialize Environment use
  67  *
  68  * We are still running from ROM, so data use is limited
  69  * Use a (moderately small) buffer on the stack
  70  */
  71 int env_init(void)
  72 {
  73         ulong crc, len, new;
  74         unsigned off;
  75         uchar buf[64];
  76
  77         eeprom_init (); /* prepare for EEPROM read/write */
  78
  79         /* read old CRC */
  80         eeprom_read (CONFIG_SYS_DEF_EEPROM_ADDR,
  81                      CONFIG_ENV_OFFSET+offsetof(env_t,crc),
  82                      (uchar *)&crc, sizeof(ulong));
  83
  84         new = 0;
  85         len = ENV_SIZE;
  86         off = offsetof(env_t,data);
  87         while (len > 0) {
  88                 int n = (len > sizeof(buf)) ? sizeof(buf) : len;
  89
  90                 eeprom_read (CONFIG_SYS_DEF_EEPROM_ADDR, CONFIG_ENV_OFFSET+off, buf, n);
  91                 new = crc32 (new, buf, n);
  92                 len -= n;
  93                 off += n;
  94         }
  95
  96         if (crc == new) {
  97                 gd->env_addr  = offsetof(env_t,data);
  98                 gd->env_valid = 1;
  99         } else {
 100                 gd->env_addr  = 0;
 101                 gd->env_valid = 0;
 102         }
 103
 104         return (0);
 105 }