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/*
* (C) Copyright 2002
* Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/io.h>
#include <asm/i8254.h>
#define TIMER1_VALUE 18 /* 15.6us */
#define TIMER2_VALUE 0x0a8e /* 440Hz */
int i8254_init(void)
{
/*
* Initialize counter 1, used to refresh request signal.
* This is required for legacy purpose as some codes like
* vgabios utilizes counter 1 to provide delay functionality.
*/
outb(PIT_CMD_CTR1 | PIT_CMD_LOW | PIT_CMD_MODE2,
PIT_BASE + PIT_COMMAND);
outb(TIMER1_VALUE, PIT_BASE + PIT_T1);
/*
* Initialize counter 2, used to drive the speaker.
* To start a beep, set both bit0 and bit1 of port 0x61.
* To stop it, clear both bit0 and bit1 of port 0x61.
*/
outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3,
PIT_BASE + PIT_COMMAND);
outb(TIMER2_VALUE & 0xff, PIT_BASE + PIT_T2);
outb(TIMER2_VALUE >> 8, PIT_BASE + PIT_T2);
return 0;
}
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