/*
 * This file is part of the coreboot project.
 *
 * Copyright 2016 Rockchip Inc.
 *
 * 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; version 2 of the License.
 *
 * 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.
 */

#include <boardid.h>
#include <console/console.h>
#include <stdlib.h>
#include <soc/saradc.h>

/*
 * ID info:
 *  ID : Volts : ADC value :   Bucket
 *  ==   =====   =========   ===========
 *   0 : 0.074V:        42 :    0 -   81
 *   1 : 0.211V:       120 :   82 -  150
 *   2 : 0.319V:       181 :  151 -  211
 *   3 : 0.427V:       242 :  212 -  274
 *   4 : 0.542V:       307 :  275 -  342
 *   5 : 0.666V:       378 :  343 -  411
 *   6 : 0.781V:       444 :  412 -  477
 *   7 : 0.900V:       511 :  478 -  545
 *   8 : 1.023V:       581 :  546 -  613
 *   9 : 1.137V:       646 :  614 -  675
 *  10 : 1.240V:       704 :  676 -  733
 *  11 : 1.343V:       763 :  734 -  795
 *  12 : 1.457V:       828 :  796 -  861
 *  13 : 1.576V:       895 :  862 -  925
 *  14 : 1.684V:       956 :  926 -  989
 *  15 : 1.800V:      1023 :  990 - 1023
 */
static const int id_readings[] = { 81, 150, 211, 274, 342, 411, 477, 545,
				  613, 675, 733, 795, 861, 925, 989, 1023 };
_Static_assert(ARRAY_SIZE(id_readings) == 16, "Yo' messed up da table, bruh!");
static int cached_board_id = -1;
static int cached_ram_id = -1;

static uint32_t get_index(uint32_t channel, int *cached_id)
{
	int i;
	int adc_reading;

	if (*cached_id != -1)
		return *cached_id;

	adc_reading = get_saradc_value(channel);
	for (i = 0; i < ARRAY_SIZE(id_readings); i++) {
		if (adc_reading <= id_readings[i]) {
			printk(BIOS_DEBUG, "ADC reading %d, ID %d\n",
			       adc_reading, i);
			*cached_id = i;
			return i;
		}
	}

	die("Read impossible value ( > 1023) from 10-bit ADC!");
}

uint8_t board_id(void)
{
	return get_index(1, &cached_board_id);
}

uint32_t ram_code(void)
{
	return get_index(0, &cached_ram_id);
}