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/*
* This file is part of the coreboot project.
*
* Copyright 2014 Google 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.
*
* 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.
*/
#include <boardid.h>
#include <gpio.h>
#include <console/console.h>
#include <stdlib.h>
/*
* Storm boards dedicate to the board ID three GPIOs in tertiary mode: 29, 30
* and 68. On proto0 GPIO68 is used and tied low, so it reads as 'zero' by
* gpio_base3_value(), whereas the other two pins are not connected
* and read as 'two'. This results in gpio_base3_value() returning
* 8 on proto0.
*
* Three tertitiary signals could represent 27 different values. To make
* calculated board ID value continuous and starting at zero, offset the
* calculated value by 19 (i.e. 27 - 8) and return modulo 27 of the offset
* number. This results in proto0 returning zero as the board ID, the future
* revisions will have the inputs configured to match the actual board
* revision.
*/
static int board_id_value = -1;
static uint8_t get_board_id(void)
{
uint8_t bid;
gpio_t hw_rev_gpios[] = {[2] = 68, [1] = 30, [0] = 29}; /* 29 is LSB */
int offset = 19;
bid = gpio_base3_value(hw_rev_gpios, ARRAY_SIZE(hw_rev_gpios));
bid = (bid + offset) % 27;
printk(BIOS_INFO, "Board ID %d\n", bid);
return bid;
}
uint8_t board_id(void)
{
if (board_id_value < 0)
board_id_value = get_board_id();
return board_id_value;
}
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