env/nvram.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * (C) Copyright 2000-2010
   4  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   5  *
   6  * (C) Copyright 2001 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   7  * Andreas Heppel <aheppel@sysgo.de>
   8  */
   9
  10 /*
  11  * 09-18-2001 Andreas Heppel, Sysgo RTS GmbH <aheppel@sysgo.de>
  12  *
  13  * It might not be possible in all cases to use 'memcpy()' to copy
  14  * the environment to NVRAM, as the NVRAM might not be mapped into
  15  * the memory space. (I.e. this is the case for the BAB750). In those
  16  * cases it might be possible to access the NVRAM using a different
  17  * method. For example, the RTC on the BAB750 is accessible in IO
  18  * space using its address and data registers. To enable usage of
  19  * NVRAM in those cases I invented the functions 'nvram_read()' and
  20  * 'nvram_write()', which will be activated upon the configuration
  21  * #define CONFIG_SYS_NVRAM_ACCESS_ROUTINE. Note, that those functions are
  22  * strongly dependent on the used HW, and must be redefined for each
  23  * board that wants to use them.
  24  */
  25
  26 #include <common.h>
  27 #include <command.h>
  28 #include <environment.h>
  29 #include <linux/stddef.h>
  30 #include <search.h>
  31 #include <errno.h>
  32
  33 DECLARE_GLOBAL_DATA_PTR;
  34
  35 #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
  36 extern void *nvram_read(void *dest, const long src, size_t count);
  37 extern void nvram_write(long dest, const void *src, size_t count);
  38 #else
  39 env_t *env_ptr = (env_t *)CONFIG_ENV_ADDR;
  40 #endif
  41
  42 #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
  43 /** Call this function from overridden env_get_char_spec() if you need
  44  * this functionality.
  45  */
  46 int env_nvram_get_char(int index)
  47 {
  48         uchar c;
  49
  50         nvram_read(&c, CONFIG_ENV_ADDR + index, 1);
  51
  52         return c;
  53 }
  54 #endif
  55
  56 static int env_nvram_load(void)
  57 {
  58         char buf[CONFIG_ENV_SIZE];
  59
  60 #if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE)
  61         nvram_read(buf, CONFIG_ENV_ADDR, CONFIG_ENV_SIZE);
  62 #else
  63         memcpy(buf, (void *)CONFIG_ENV_ADDR, CONFIG_ENV_SIZE);
  64 #endif
  65         return env_import(buf, 1);
  66 }
  67
  68 static int env_nvram_save(void)
  69 {
  70         env_t   env_new;
  71         int     rcode = 0;
  72
  73         rcode = env_export(&env_new);
  74         if (rcode)
  75                 return rcode;
  76
  77 #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
  78         nvram_write(CONFIG_ENV_ADDR, &env_new, CONFIG_ENV_SIZE);
  79 #else
  80         if (memcpy((char *)CONFIG_ENV_ADDR, &env_new, CONFIG_ENV_SIZE) == NULL)
  81                 rcode = 1;
  82 #endif
  83         return rcode;
  84 }
  85
  86 /*
  87  * Initialize Environment use
  88  *
  89  * We are still running from ROM, so data use is limited
  90  */
  91 static int env_nvram_init(void)
  92 {
  93 #if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE)
  94         ulong crc;
  95         uchar data[ENV_SIZE];
  96
  97         nvram_read(&crc, CONFIG_ENV_ADDR, sizeof(ulong));
  98         nvram_read(data, CONFIG_ENV_ADDR + sizeof(ulong), ENV_SIZE);
  99
 100         if (crc32(0, data, ENV_SIZE) == crc) {
 101                 gd->env_addr    = (ulong)CONFIG_ENV_ADDR + sizeof(long);
 102 #else
 103         if (crc32(0, env_ptr->data, ENV_SIZE) == env_ptr->crc) {
 104                 gd->env_addr    = (ulong)&env_ptr->data;
 105 #endif
 106                 gd->env_valid = ENV_VALID;
 107         } else {
 108                 gd->env_addr    = (ulong)&default_environment[0];
 109                 gd->env_valid   = ENV_INVALID;
 110         }
 111
 112         return 0;
 113 }
 114
 115 U_BOOT_ENV_LOCATION(nvram) = {
 116         .location       = ENVL_NVRAM,
 117         ENV_NAME("NVRAM")
 118         .load           = env_nvram_load,
 119         .save           = env_save_ptr(env_nvram_save),
 120         .init           = env_nvram_init,
 121 };