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/*
* 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);
}
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