common/env_dataflash.c

   1 /* LowLevel function for DataFlash environment support
   2  * Author : Gilles Gastaldi (Atmel)
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of
   7  * the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  17  * MA 02111-1307 USA
  18  *
  19  */
  20 #include <common.h>
  21 #include <command.h>
  22 #include <environment.h>
  23 #include <linux/stddef.h>
  24 #include <dataflash.h>
  25
  26 DECLARE_GLOBAL_DATA_PTR;
  27
  28 env_t *env_ptr = NULL;
  29
  30 char * env_name_spec = "dataflash";
  31
  32 extern int read_dataflash (unsigned long addr, unsigned long size, char
  33 *result);
  34 extern int write_dataflash (unsigned long addr_dest, unsigned long addr_src,
  35                      unsigned long size);
  36 extern int AT91F_DataflashInit (void);
  37 extern uchar default_environment[];
  38
  39
  40 uchar env_get_char_spec (int index)
  41 {
  42         uchar c;
  43         read_dataflash(CONFIG_ENV_ADDR + index + offsetof(env_t,data),
  44         1, (char *)&c);
  45         return (c);
  46 }
  47
  48 void env_relocate_spec (void)
  49 {
  50         read_dataflash(CONFIG_ENV_ADDR, CONFIG_ENV_SIZE, (char *)env_ptr);
  51 }
  52
  53 int saveenv(void)
  54 {
  55         /* env must be copied to do not alter env structure in memory*/
  56         unsigned char temp[CONFIG_ENV_SIZE];
  57         memcpy(temp, env_ptr, CONFIG_ENV_SIZE);
  58         return write_dataflash(CONFIG_ENV_ADDR, (unsigned long)temp, CONFIG_ENV_SIZE);
  59 }
  60
  61 /************************************************************************
  62  * Initialize Environment use
  63  *
  64  * We are still running from ROM, so data use is limited
  65  * Use a (moderately small) buffer on the stack
  66  */
  67 int env_init(void)
  68 {
  69         ulong crc, len, new;
  70         unsigned off;
  71         uchar buf[64];
  72         if (gd->env_valid == 0){
  73                 AT91F_DataflashInit();  /* prepare for DATAFLASH read/write */
  74
  75                 /* read old CRC */
  76                 read_dataflash(CONFIG_ENV_ADDR + offsetof(env_t, crc),
  77                         sizeof(ulong), (char *)&crc);
  78                 new = 0;
  79                 len = ENV_SIZE;
  80                 off = offsetof(env_t,data);
  81                 while (len > 0) {
  82                         int n = (len > sizeof(buf)) ? sizeof(buf) : len;
  83                         read_dataflash(CONFIG_ENV_ADDR + off, n, (char *)buf);
  84                         new = crc32 (new, buf, n);
  85                         len -= n;
  86                         off += n;
  87                 }
  88                 if (crc == new) {
  89                         gd->env_addr  = offsetof(env_t,data);
  90                         gd->env_valid = 1;
  91                 } else {
  92                         gd->env_addr  = (ulong)&default_environment[0];
  93                         gd->env_valid = 0;
  94                 }
  95         }
  96
  97         return (0);
  98 }