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 /** Call this function from overridden env_get_char_spec() if you need
  45  * this functionality.
  46  */
  47 int env_nvram_get_char(int index)
  48 {
  49         uchar c;
  50
  51         nvram_read(&c, CONFIG_ENV_ADDR + index, 1);
  52
  53         return c;
  54 }
  55 #endif
  56
  57 static int env_nvram_load(void)
  58 {
  59         char buf[CONFIG_ENV_SIZE];
  60
  61 #if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE)
  62         nvram_read(buf, CONFIG_ENV_ADDR, CONFIG_ENV_SIZE);
  63 #else
  64         memcpy(buf, (void *)CONFIG_ENV_ADDR, CONFIG_ENV_SIZE);
  65 #endif
  66         return env_import(buf, 1);
  67 }
  68
  69 static int env_nvram_save(void)
  70 {
  71         env_t   env_new;
  72         int     rcode = 0;
  73
  74         rcode = env_export(&env_new);
  75         if (rcode)
  76                 return rcode;
  77
  78 #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
  79         nvram_write(CONFIG_ENV_ADDR, &env_new, CONFIG_ENV_SIZE);
  80 #else
  81         if (memcpy((char *)CONFIG_ENV_ADDR, &env_new, CONFIG_ENV_SIZE) == NULL)
  82                 rcode = 1;
  83 #endif
  84         return rcode;
  85 }
  86
  87 /*
  88  * Initialize Environment use
  89  *
  90  * We are still running from ROM, so data use is limited
  91  */
  92 static int env_nvram_init(void)
  93 {
  94 #if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE)
  95         ulong crc;
  96         uchar data[ENV_SIZE];
  97
  98         nvram_read(&crc, CONFIG_ENV_ADDR, sizeof(ulong));
  99         nvram_read(data, CONFIG_ENV_ADDR + sizeof(ulong), ENV_SIZE);
 100
 101         if (crc32(0, data, ENV_SIZE) == crc) {
 102                 gd->env_addr    = (ulong)CONFIG_ENV_ADDR + sizeof(long);
 103 #else
 104         if (crc32(0, env_ptr->data, ENV_SIZE) == env_ptr->crc) {
 105                 gd->env_addr    = (ulong)&env_ptr->data;
 106 #endif
 107                 gd->env_valid = ENV_VALID;
 108         } else {
 109                 gd->env_addr    = (ulong)&default_environment[0];
 110                 gd->env_valid   = ENV_INVALID;
 111         }
 112
 113         return 0;
 114 }
 115
 116 U_BOOT_ENV_LOCATION(nvram) = {
 117         .location       = ENVL_NVRAM,
 118         ENV_NAME("NVRAM")
 119         .load           = env_nvram_load,
 120         .save           = env_save_ptr(env_nvram_save),
 121         .init           = env_nvram_init,
 122 };