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 #if defined(CONFIG_I2C_ENV_EEPROM_BUS)
  32 #include <i2c.h>
  33 #endif
  34
  35 DECLARE_GLOBAL_DATA_PTR;
  36
  37 env_t *env_ptr = NULL;
  38
  39 char * env_name_spec = "EEPROM";
  40 int env_eeprom_bus = -1;
  41
  42 static int eeprom_bus_read (unsigned dev_addr, unsigned offset, uchar *buffer,
  43                                 unsigned cnt)
  44 {
  45         int rcode;
  46 #if defined(CONFIG_I2C_ENV_EEPROM_BUS)
  47         int old_bus = i2c_get_bus_num();
  48
  49         if (gd->flags & GD_FLG_RELOC) {
  50                 if (env_eeprom_bus == -1) {
  51                         I2C_MUX_DEVICE *dev = NULL;
  52                         dev = i2c_mux_ident_muxstring(
  53                                 (uchar *)CONFIG_I2C_ENV_EEPROM_BUS);
  54                         if (dev != NULL) {
  55                                 env_eeprom_bus = dev->busid;
  56                         } else
  57                                 printf ("error adding env eeprom bus.\n");
  58                 }
  59                 if (old_bus != env_eeprom_bus) {
  60                         i2c_set_bus_num(env_eeprom_bus);
  61                         old_bus = env_eeprom_bus;
  62                 }
  63         } else {
  64                 rcode = i2c_mux_ident_muxstring_f(
  65                                 (uchar *)CONFIG_I2C_ENV_EEPROM_BUS);
  66         }
  67 #endif
  68
  69         rcode = eeprom_read (dev_addr, offset, buffer, cnt);
  70 #if defined(CONFIG_I2C_ENV_EEPROM_BUS)
  71         if (old_bus != env_eeprom_bus)
  72                 i2c_set_bus_num(old_bus);
  73 #endif
  74         return rcode;
  75 }
  76
  77 static int eeprom_bus_write (unsigned dev_addr, unsigned offset, uchar *buffer,
  78                                 unsigned cnt)
  79 {
  80         int rcode;
  81 #if defined(CONFIG_I2C_ENV_EEPROM_BUS)
  82         int old_bus = i2c_get_bus_num();
  83
  84         rcode = i2c_mux_ident_muxstring_f((uchar *)CONFIG_I2C_ENV_EEPROM_BUS);
  85 #endif
  86         rcode = eeprom_write (dev_addr, offset, buffer, cnt);
  87 #if defined(CONFIG_I2C_ENV_EEPROM_BUS)
  88         i2c_set_bus_num(old_bus);
  89 #endif
  90         return rcode;
  91 }
  92
  93 uchar env_get_char_spec (int index)
  94 {
  95         uchar c;
  96
  97         eeprom_bus_read (CONFIG_SYS_DEF_EEPROM_ADDR,
  98                      CONFIG_ENV_OFFSET+index+offsetof(env_t,data),
  99                      &c, 1);
 100
 101         return (c);
 102 }
 103
 104 void env_relocate_spec (void)
 105 {
 106         eeprom_bus_read (CONFIG_SYS_DEF_EEPROM_ADDR,
 107                      CONFIG_ENV_OFFSET,
 108                      (uchar*)env_ptr,
 109                      CONFIG_ENV_SIZE);
 110 }
 111
 112 int saveenv(void)
 113 {
 114         return eeprom_bus_write (CONFIG_SYS_DEF_EEPROM_ADDR,
 115                              CONFIG_ENV_OFFSET,
 116                              (uchar *)env_ptr,
 117                              CONFIG_ENV_SIZE);
 118 }
 119
 120 /************************************************************************
 121  * Initialize Environment use
 122  *
 123  * We are still running from ROM, so data use is limited
 124  * Use a (moderately small) buffer on the stack
 125  */
 126 int env_init(void)
 127 {
 128         ulong crc, len, new;
 129         unsigned off;
 130         uchar buf[64];
 131
 132         eeprom_init (); /* prepare for EEPROM read/write */
 133
 134         /* read old CRC */
 135         eeprom_bus_read (CONFIG_SYS_DEF_EEPROM_ADDR,
 136                      CONFIG_ENV_OFFSET+offsetof(env_t,crc),
 137                      (uchar *)&crc, sizeof(ulong));
 138
 139         new = 0;
 140         len = ENV_SIZE;
 141         off = offsetof(env_t,data);
 142         while (len > 0) {
 143                 int n = (len > sizeof(buf)) ? sizeof(buf) : len;
 144
 145                 eeprom_bus_read (CONFIG_SYS_DEF_EEPROM_ADDR,
 146                                 CONFIG_ENV_OFFSET + off, buf, n);
 147                 new = crc32 (new, buf, n);
 148                 len -= n;
 149                 off += n;
 150         }
 151
 152         if (crc == new) {
 153                 gd->env_addr  = offsetof(env_t,data);
 154                 gd->env_valid = 1;
 155         } else {
 156                 gd->env_addr  = 0;
 157                 gd->env_valid = 0;
 158         }
 159
 160         return (0);
 161 }