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 DECLARE_GLOBAL_DATA_PTR;
  36
  37 env_t *env_ptr = NULL;
  38
  39 char * env_name_spec = "EEPROM";
  40
  41 extern uchar env_get_char_memory (int index);
  42
  43
  44 uchar env_get_char_spec (int index)
  45 {
  46         uchar c;
  47
  48         eeprom_read (CFG_DEF_EEPROM_ADDR,
  49                      CFG_ENV_OFFSET+index+offsetof(env_t,data),
  50                      &c, 1);
  51
  52         return (c);
  53 }
  54
  55 void env_relocate_spec (void)
  56 {
  57         eeprom_read (CFG_DEF_EEPROM_ADDR,
  58                      CFG_ENV_OFFSET,
  59                      (uchar*)env_ptr,
  60                      CFG_ENV_SIZE);
  61 }
  62
  63 int saveenv(void)
  64 {
  65         return eeprom_write (CFG_DEF_EEPROM_ADDR,
  66                              CFG_ENV_OFFSET,
  67                              (uchar *)env_ptr,
  68                              CFG_ENV_SIZE);
  69 }
  70
  71 /************************************************************************
  72  * Initialize Environment use
  73  *
  74  * We are still running from ROM, so data use is limited
  75  * Use a (moderately small) buffer on the stack
  76  */
  77 int env_init(void)
  78 {
  79         ulong crc, len, new;
  80         unsigned off;
  81         uchar buf[64];
  82
  83         eeprom_init (); /* prepare for EEPROM read/write */
  84
  85         /* read old CRC */
  86         eeprom_read (CFG_DEF_EEPROM_ADDR,
  87                      CFG_ENV_OFFSET+offsetof(env_t,crc),
  88                      (uchar *)&crc, sizeof(ulong));
  89
  90         new = 0;
  91         len = ENV_SIZE;
  92         off = offsetof(env_t,data);
  93         while (len > 0) {
  94                 int n = (len > sizeof(buf)) ? sizeof(buf) : len;
  95
  96                 eeprom_read (CFG_DEF_EEPROM_ADDR, CFG_ENV_OFFSET+off, buf, n);
  97                 new = crc32 (new, buf, n);
  98                 len -= n;
  99                 off += n;
 100         }
 101
 102         if (crc == new) {
 103                 gd->env_addr  = offsetof(env_t,data);
 104                 gd->env_valid = 1;
 105         } else {
 106                 gd->env_addr  = 0;
 107                 gd->env_valid = 0;
 108         }
 109
 110         return (0);
 111 }
 112
 113 #endif /* CFG_ENV_IS_IN_EEPROM */