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st-u-boot / env / eeprom.c
// 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>
 */

#include <common.h>
#include <command.h>
#include <i2c.h>
#include <i2c_eeprom.h>
#include <env.h>
#include <env_internal.h>
#include <asm/global_data.h>
#include <linux/stddef.h>
#include <u-boot/crc.h>
#include <search.h>
#include <errno.h>
#include <linux/compiler.h>	/* for BUG_ON */
#include <asm/gpio.h>

DECLARE_GLOBAL_DATA_PTR;

static struct udevice *env_eeprom_dev(void)
{
	struct udevice *dev;
	int ret;

	ret = i2c_get_chip_for_busnum(CONFIG_I2C_ENV_EEPROM_BUS,
		CONFIG_SYS_I2C_EEPROM_ADDR, 1, &dev);

	if (ret) {
		printf("%s: Cannot find udev for a bus %d\n", __func__,
		       CONFIG_I2C_ENV_EEPROM_BUS);
	}

	return dev;
}
	
static int env_eeprom_load(void)
{
	char buf_env[CONFIG_ENV_SIZE];
	unsigned int off = CONFIG_ENV_OFFSET;
	struct udevice *dev = env_eeprom_dev();

	if(!dev)
		return CMD_RET_FAILURE;

#ifdef CONFIG_ENV_OFFSET_REDUND
	ulong len, crc[2], crc_tmp;
	unsigned int off_env[2];
	uchar rdbuf[64], flags[2];
	int i, crc_ok[2] = {0, 0};

	off_env[0] = CONFIG_ENV_OFFSET;
	off_env[1] = CONFIG_ENV_OFFSET_REDUND;

	for (i = 0; i < 2; i++) {
		/* read CRC */
		i2c_eeprom_read(dev, off_env[i] + offsetof(env_t, crc),
				(uchar *)&crc[i], sizeof(ulong));
		/* read FLAGS */
		i2c_eeprom_read(dev, off_env[i] + offsetof(env_t, flags),
				(uchar *)&flags[i], sizeof(uchar));

		crc_tmp = 0;
		len = ENV_SIZE;
		off = off_env[i] + offsetof(env_t, data);
		while (len > 0) {
			int n = (len > sizeof(rdbuf)) ? sizeof(rdbuf) : len;

			i2c_eeprom_read(dev, off, rdbuf, n);

			crc_tmp = crc32(crc_tmp, rdbuf, n);
			len -= n;
			off += n;
		}

		if (crc_tmp == crc[i])
			crc_ok[i] = 1;
	}

	if (!crc_ok[0] && !crc_ok[1]) {
		gd->env_addr	= 0;
		gd->env_valid = ENV_INVALID;
	} else if (crc_ok[0] && !crc_ok[1]) {
		gd->env_valid = ENV_VALID;
	} else if (!crc_ok[0] && crc_ok[1]) {
		gd->env_valid = ENV_REDUND;
	} else {
		/* both ok - check serial */
		if (flags[0] == ENV_REDUND_ACTIVE &&
		    flags[1] == ENV_REDUND_OBSOLETE)
			gd->env_valid = ENV_VALID;
		else if (flags[0] == ENV_REDUND_OBSOLETE &&
			 flags[1] == ENV_REDUND_ACTIVE)
			gd->env_valid = ENV_REDUND;
		else if (flags[0] == 0xFF && flags[1] == 0)
			gd->env_valid = ENV_REDUND;
		else if (flags[1] == 0xFF && flags[0] == 0)
			gd->env_valid = ENV_VALID;
		else /* flags are equal - almost impossible */
			gd->env_valid = ENV_VALID;
	}

#else /* CONFIG_ENV_OFFSET_REDUND */
	ulong crc, len, new;
	uchar rdbuf[64];

	/* read old CRC */
	i2c_eeprom_read(dev, CONFIG_ENV_OFFSET + offsetof(env_t, crc),
			(uchar *)&crc, sizeof(ulong));

	new = 0;
	len = ENV_SIZE;
	off = offsetof(env_t, data);
	while (len > 0) {
		int n = (len > sizeof(rdbuf)) ? sizeof(rdbuf) : len;

		i2c_eeprom_read(dev, CONFIG_ENV_OFFSET + off, rdbuf, n);
		new = crc32(new, rdbuf, n);
		len -= n;
		off += n;
	}

	if (crc == new) {
		gd->env_valid = ENV_VALID;
	} else {
		gd->env_valid = ENV_INVALID;
	}
#endif /* CONFIG_ENV_OFFSET_REDUND */

	off = CONFIG_ENV_OFFSET;
#ifdef CONFIG_ENV_OFFSET_REDUND
	if (gd->env_valid == ENV_REDUND)
		off = CONFIG_ENV_OFFSET_REDUND;
#endif

	i2c_eeprom_read(dev, off, (uchar *)buf_env, CONFIG_ENV_SIZE);

	return env_import(buf_env, 1, H_EXTERNAL);
}

static int env_eeprom_save(void)
{
	env_t	env_new;
	int	rc;
	unsigned int off	= CONFIG_ENV_OFFSET;
#ifdef CONFIG_ENV_OFFSET_REDUND
	unsigned int off_red	= CONFIG_ENV_OFFSET_REDUND;
	char flag_obsolete	= ENV_REDUND_OBSOLETE;
#endif
	struct udevice *dev = env_eeprom_dev();
	struct gpio_desc wp_gpio;

	if(!dev)
		return CMD_RET_FAILURE;

	gpio_request_by_name(dev, "wp-gpios", 0, &wp_gpio, GPIOD_IS_IN);

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

#ifdef CONFIG_ENV_OFFSET_REDUND
	if (gd->env_valid == ENV_VALID) {
		off	= CONFIG_ENV_OFFSET_REDUND;
		off_red	= CONFIG_ENV_OFFSET;
	}

	env_new.flags = ENV_REDUND_ACTIVE;
#endif

	if (dm_gpio_is_valid(&wp_gpio))
		dm_gpio_set_value(&wp_gpio, 1);

	rc = i2c_eeprom_write(dev, off, (uchar *)&env_new, CONFIG_ENV_SIZE);

#ifdef CONFIG_ENV_OFFSET_REDUND
	if (rc == 0) {
		i2c_eeprom_write(dev, off_red + offsetof(env_t, flags),
				 (uchar *)&flag_obsolete, 1);

		if (gd->env_valid == ENV_VALID)
			gd->env_valid = ENV_REDUND;
		else
			gd->env_valid = ENV_VALID;
	}
#endif

	if (dm_gpio_is_valid(&wp_gpio))
		dm_gpio_set_value(&wp_gpio, 0);

	return rc;
}

U_BOOT_ENV_LOCATION(eeprom) = {
	.location	= ENVL_EEPROM,
	ENV_NAME("EEPROM")
	.load		= env_eeprom_load,
	.save		= env_save_ptr(env_eeprom_save),
};