env/nvram.c

   1 /*
   2  * (C) Copyright 2000-2010
   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  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11 /*
  12  * 09-18-2001 Andreas Heppel, Sysgo RTS GmbH <aheppel@sysgo.de>
  13  *
  14  * It might not be possible in all cases to use 'memcpy()' to copy
  15  * the environment to NVRAM, as the NVRAM might not be mapped into
  16  * the memory space. (I.e. this is the case for the BAB750). In those
  17  * cases it might be possible to access the NVRAM using a different
  18  * method. For example, the RTC on the BAB750 is accessible in IO
  19  * space using its address and data registers. To enable usage of
  20  * NVRAM in those cases I invented the functions 'nvram_read()' and
  21  * 'nvram_write()', which will be activated upon the configuration
  22  * #define CONFIG_SYS_NVRAM_ACCESS_ROUTINE. Note, that those functions are
  23  * strongly dependent on the used HW, and must be redefined for each
  24  * board that wants to use them.
  25  */
  26
  27 #include <common.h>
  28 #include <command.h>
  29 #include <environment.h>
  30 #include <linux/stddef.h>
  31 #include <search.h>
  32 #include <errno.h>
  33
  34 DECLARE_GLOBAL_DATA_PTR;
  35
  36 #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
  37 extern void *nvram_read(void *dest, const long src, size_t count);
  38 extern void nvram_write(long dest, const void *src, size_t count);
  39 #else
  40 env_t *env_ptr = (env_t *)CONFIG_ENV_ADDR;
  41 #endif
  42
  43 #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
  44 static int env_nvram_get_char(int index)
  45 {
  46         uchar c;
  47
  48         nvram_read(&c, CONFIG_ENV_ADDR + index, 1);
  49
  50         return c;
  51 }
  52 #endif
  53
  54 static int env_nvram_load(void)
  55 {
  56         char buf[CONFIG_ENV_SIZE];
  57
  58 #if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE)
  59         nvram_read(buf, CONFIG_ENV_ADDR, CONFIG_ENV_SIZE);
  60 #else
  61         memcpy(buf, (void *)CONFIG_ENV_ADDR, CONFIG_ENV_SIZE);
  62 #endif
  63         return env_import(buf, 1);
  64 }
  65
  66 static int env_nvram_save(void)
  67 {
  68         env_t   env_new;
  69         int     rcode = 0;
  70
  71         rcode = env_export(&env_new);
  72         if (rcode)
  73                 return rcode;
  74
  75 #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
  76         nvram_write(CONFIG_ENV_ADDR, &env_new, CONFIG_ENV_SIZE);
  77 #else
  78         if (memcpy((char *)CONFIG_ENV_ADDR, &env_new, CONFIG_ENV_SIZE) == NULL)
  79                 rcode = 1;
  80 #endif
  81         return rcode;
  82 }
  83
  84 /*
  85  * Initialize Environment use
  86  *
  87  * We are still running from ROM, so data use is limited
  88  */
  89 static int env_nvram_init(void)
  90 {
  91 #if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE)
  92         ulong crc;
  93         uchar data[ENV_SIZE];
  94
  95         nvram_read(&crc, CONFIG_ENV_ADDR, sizeof(ulong));
  96         nvram_read(data, CONFIG_ENV_ADDR + sizeof(ulong), ENV_SIZE);
  97
  98         if (crc32(0, data, ENV_SIZE) == crc) {
  99                 gd->env_addr    = (ulong)CONFIG_ENV_ADDR + sizeof(long);
 100 #else
 101         if (crc32(0, env_ptr->data, ENV_SIZE) == env_ptr->crc) {
 102                 gd->env_addr    = (ulong)&env_ptr->data;
 103 #endif
 104                 gd->env_valid = ENV_VALID;
 105         } else {
 106                 gd->env_addr    = (ulong)&default_environment[0];
 107                 gd->env_valid   = ENV_INVALID;
 108         }
 109
 110         return 0;
 111 }
 112
 113 U_BOOT_ENV_LOCATION(nvram) = {
 114         .location       = ENVL_NVRAM,
 115         ENV_NAME("NVRAM")
 116 #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
 117         .get_char       = env_nvram_get_char,
 118 #endif
 119         .load           = env_nvram_load,
 120         .save           = env_save_ptr(env_nvram_save),
 121         .init           = env_nvram_init,
 122 };