// SPDX-License-Identifier: GPL-2.0+

  /*

   * (C) Copyright 2000-2010

   * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   *
   * (C) Copyright 2001 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   * Andreas Heppel <aheppel@sysgo.de>

   */
  
  /*
   * 09-18-2001 Andreas Heppel, Sysgo RTS GmbH <aheppel@sysgo.de>
   *
   * It might not be possible in all cases to use 'memcpy()' to copy
   * the environment to NVRAM, as the NVRAM might not be mapped into
   * the memory space. (I.e. this is the case for the BAB750). In those
   * cases it might be possible to access the NVRAM using a different
   * method. For example, the RTC on the BAB750 is accessible in IO
   * space using its address and data registers. To enable usage of
   * NVRAM in those cases I invented the functions 'nvram_read()' and
   * 'nvram_write()', which will be activated upon the configuration

   * #define CONFIG_SYS_NVRAM_ACCESS_ROUTINE. Note, that those functions are

   * strongly dependent on the used HW, and must be redefined for each
   * board that wants to use them.
   */
  
  #include <common.h>

  #include <command.h>

  #include <env.h>

  #include <env_internal.h>

  #include <linux/stddef.h>

  #include <search.h>
  #include <errno.h>

  #include <u-boot/crc.h>

  DECLARE_GLOBAL_DATA_PTR;

  #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE

  extern void *nvram_read(void *dest, const long src, size_t count);
  extern void nvram_write(long dest, const void *src, size_t count);

  #else

  env_t *env_ptr = (env_t *)CONFIG_ENV_ADDR;

  #endif

  #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE

  /** Call this function from overridden env_get_char_spec() if you need
   * this functionality.
   */
  int env_nvram_get_char(int index)

  {

  	uchar c;

  	nvram_read(&c, CONFIG_ENV_ADDR + index, 1);

  
  	return c;

  }

  #endif

  static int env_nvram_load(void)

  {

  	char buf[CONFIG_ENV_SIZE];

  #if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE)

  	nvram_read(buf, CONFIG_ENV_ADDR, CONFIG_ENV_SIZE);

  #else

  	memcpy(buf, (void *)CONFIG_ENV_ADDR, CONFIG_ENV_SIZE);

  #endif

  	return env_import(buf, 1);

  }

  static int env_nvram_save(void)

  {

  	env_t	env_new;

  	int	rcode = 0;

  	rcode = env_export(&env_new);
  	if (rcode)
  		return rcode;

  #ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE

  	nvram_write(CONFIG_ENV_ADDR, &env_new, CONFIG_ENV_SIZE);
  #else
  	if (memcpy((char *)CONFIG_ENV_ADDR, &env_new, CONFIG_ENV_SIZE) == NULL)
  		rcode = 1;

  #endif
  	return rcode;
  }

  /*

   * Initialize Environment use
   *
   * We are still running from ROM, so data use is limited
   */

  static int env_nvram_init(void)

  {

  #if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE)

  	ulong crc;

  	uchar data[ENV_SIZE];

  
  	nvram_read(&crc, CONFIG_ENV_ADDR, sizeof(ulong));

  	nvram_read(data, CONFIG_ENV_ADDR + sizeof(ulong), ENV_SIZE);

  
  	if (crc32(0, data, ENV_SIZE) == crc) {

  		gd->env_addr	= (ulong)CONFIG_ENV_ADDR + sizeof(long);

  #else
  	if (crc32(0, env_ptr->data, ENV_SIZE) == env_ptr->crc) {

  		gd->env_addr	= (ulong)&env_ptr->data;

  #endif

  		gd->env_valid = ENV_VALID;

  	} else {

  		gd->env_addr	= (ulong)&default_environment[0];

  		gd->env_valid	= ENV_INVALID;

  	}

  
  	return 0;

  }

  
  U_BOOT_ENV_LOCATION(nvram) = {
  	.location	= ENVL_NVRAM,

  	ENV_NAME("NVRAM")

  	.load		= env_nvram_load,
  	.save		= env_save_ptr(env_nvram_save),
  	.init		= env_nvram_init,

  };