1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * (C) Copyright 2002
3*4882a593Smuzhiyun * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * SPDX-License-Identifier: GPL-2.0+
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <common.h>
9*4882a593Smuzhiyun #include <asm/io.h>
10*4882a593Smuzhiyun #include <asm/i8254.h>
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #define TIMER1_VALUE 18 /* 15.6us */
13*4882a593Smuzhiyun #define TIMER2_VALUE 0x0a8e /* 440Hz */
14*4882a593Smuzhiyun
i8254_init(void)15*4882a593Smuzhiyun int i8254_init(void)
16*4882a593Smuzhiyun {
17*4882a593Smuzhiyun /*
18*4882a593Smuzhiyun * Initialize counter 1, used to refresh request signal.
19*4882a593Smuzhiyun * This is required for legacy purpose as some codes like
20*4882a593Smuzhiyun * vgabios utilizes counter 1 to provide delay functionality.
21*4882a593Smuzhiyun */
22*4882a593Smuzhiyun outb(PIT_CMD_CTR1 | PIT_CMD_LOW | PIT_CMD_MODE2,
23*4882a593Smuzhiyun PIT_BASE + PIT_COMMAND);
24*4882a593Smuzhiyun outb(TIMER1_VALUE, PIT_BASE + PIT_T1);
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun /*
27*4882a593Smuzhiyun * Initialize counter 2, used to drive the speaker.
28*4882a593Smuzhiyun * To start a beep, set both bit0 and bit1 of port 0x61.
29*4882a593Smuzhiyun * To stop it, clear both bit0 and bit1 of port 0x61.
30*4882a593Smuzhiyun */
31*4882a593Smuzhiyun outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3,
32*4882a593Smuzhiyun PIT_BASE + PIT_COMMAND);
33*4882a593Smuzhiyun outb(TIMER2_VALUE & 0xff, PIT_BASE + PIT_T2);
34*4882a593Smuzhiyun outb(TIMER2_VALUE >> 8, PIT_BASE + PIT_T2);
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun return 0;
37*4882a593Smuzhiyun }
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