1*da3fe247SBin Meng /*
2*da3fe247SBin Meng * (C) Copyright 2002
3*da3fe247SBin Meng * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
4*da3fe247SBin Meng *
5*da3fe247SBin Meng * SPDX-License-Identifier: GPL-2.0+
6*da3fe247SBin Meng */
7*da3fe247SBin Meng
8*da3fe247SBin Meng #include <common.h>
9*da3fe247SBin Meng #include <asm/io.h>
10*da3fe247SBin Meng #include <asm/i8254.h>
11*da3fe247SBin Meng
12*da3fe247SBin Meng #define TIMER1_VALUE 18 /* 15.6us */
13*da3fe247SBin Meng #define TIMER2_VALUE 0x0a8e /* 440Hz */
14*da3fe247SBin Meng
i8254_init(void)15*da3fe247SBin Meng int i8254_init(void)
16*da3fe247SBin Meng {
17*da3fe247SBin Meng /*
18*da3fe247SBin Meng * Initialize counter 1, used to refresh request signal.
19*da3fe247SBin Meng * This is required for legacy purpose as some codes like
20*da3fe247SBin Meng * vgabios utilizes counter 1 to provide delay functionality.
21*da3fe247SBin Meng */
22*da3fe247SBin Meng outb(PIT_CMD_CTR1 | PIT_CMD_LOW | PIT_CMD_MODE2,
23*da3fe247SBin Meng PIT_BASE + PIT_COMMAND);
24*da3fe247SBin Meng outb(TIMER1_VALUE, PIT_BASE + PIT_T1);
25*da3fe247SBin Meng
26*da3fe247SBin Meng /*
27*da3fe247SBin Meng * Initialize counter 2, used to drive the speaker.
28*da3fe247SBin Meng * To start a beep, set both bit0 and bit1 of port 0x61.
29*da3fe247SBin Meng * To stop it, clear both bit0 and bit1 of port 0x61.
30*da3fe247SBin Meng */
31*da3fe247SBin Meng outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3,
32*da3fe247SBin Meng PIT_BASE + PIT_COMMAND);
33*da3fe247SBin Meng outb(TIMER2_VALUE & 0xff, PIT_BASE + PIT_T2);
34*da3fe247SBin Meng outb(TIMER2_VALUE >> 8, PIT_BASE + PIT_T2);
35*da3fe247SBin Meng
36*da3fe247SBin Meng return 0;
37*da3fe247SBin Meng }
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