common/env_nvram.c

/*
 * (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>

 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

/*
 * 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 <environment.h>
#include <linux/stddef.h>
#include <search.h>
#include <errno.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);
env_t *env_ptr;
#else
env_t *env_ptr = (env_t *)CONFIG_ENV_ADDR;
#endif

char *env_name_spec = "NVRAM";

#ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
static char env_buf[CONFIG_ENV_SIZE];
#endif

#ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
uchar env_get_char_spec(int index)
{
	uchar c;

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

	return c;
}
#endif

void env_relocate_spec(void)
{
	char *buf;

#if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE)
	buf = env_buf;
	nvram_read(buf, CONFIG_ENV_ADDR, CONFIG_ENV_SIZE);
#else
	buf = (void *)CONFIG_ENV_ADDR;
#endif
	env_import(buf, 1);
}

int saveenv(void)
{
#ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
	env_t	*env_new = (env_t *)env_buf;
#else
	env_t	*env_new = (env_t *)CONFIG_ENV_ADDR;
#endif
	ssize_t	len;
	char	*res;
	int	rcode = 0;

	res = (char *)env_new->data;
	len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, 0, NULL);
	if (len < 0) {
		error("Cannot export environment: errno = %d\n", errno);
		return 1;
	}
	env_new->crc = crc32(0, env_new->data, ENV_SIZE);

#ifdef CONFIG_SYS_NVRAM_ACCESS_ROUTINE
	nvram_write(CONFIG_ENV_ADDR, env_new, CONFIG_ENV_SIZE);
#endif
	return rcode;
}

/*
 * Initialize Environment use
 *
 * We are still running from ROM, so data use is limited
 */
int env_init(void)
{
#if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE)
	ulong crc;
	uchar *data = env_buf;

	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	= 1;
	} else {
		gd->env_addr	= (ulong)&default_environment[0];
		gd->env_valid	= 0;
	}

	return 0;
}