1 /*
2 *
3 * Copyright (C) 2007 Uwe Hermann <[email protected]>
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 /*
30 * Datasheet:
31 * - Name: 82C54 CHMOS Programmable Interval Timer
32 * - PDF: http://www.intel.com/design/archives/periphrl/docs/23124406.pdf
33 * - Order number: 231244-006
34 */
35
36 #include <libpayload.h>
37
38 #define I82C54_CONTROL_WORD_REGISTER 0x43 /* Write-only. */
39
40 #define I82C54_COUNTER0 0x40
41 #define I82C54_COUNTER1 0x41
42 #define I82C54_COUNTER2 0x42
43
44 #define PC_SPEAKER_PORT 0x61
45
46 /**
47 * Use the PC speaker to create a tone/sound of the specified frequency.
48 *
49 * The Intel 82C54 CHMOS Programmable Interval Timer (PIT) provides a
50 * superset of the functions of the original Intel 8253/8254 PIT. It has
51 * three programmable counters/timers (counter 0, 1, and 2). Counter 2 can
52 * be used to generate tones/sounds of various frequencies and duration.
53 *
54 * See also:
55 * - http://en.wikipedia.org/wiki/Pc_speaker
56 * - http://en.wikipedia.org/wiki/Intel_8253
57 *
58 * @param freq The frequency of the tone.
59 */
speaker_enable(u16 freq)60 void speaker_enable(u16 freq)
61 {
62 u16 reg16 = 1193180 / freq;
63
64 /* Select counter 2. Read/write LSB first, then MSB. Use mode 3
65 (square wave generator). Use a 16bit binary counter. */
66 outb(0xb6, I82C54_CONTROL_WORD_REGISTER);
67
68 /* Set the desired tone frequency. */
69 outb((u8)(reg16 & 0x00ff), I82C54_COUNTER2); /* LSB. */
70 outb((u8)(reg16 >> 8), I82C54_COUNTER2); /* MSB. */
71
72 /* Enable the PC speaker (set bits 0 and 1). */
73 outb(inb(PC_SPEAKER_PORT) | 0x03, PC_SPEAKER_PORT);
74 }
75
76 /**
77 * Disable the PC speaker.
78 */
speaker_disable(void)79 void speaker_disable(void)
80 {
81 /* Disable the PC speaker (clear bits 0 and 1). */
82 outb(inb(PC_SPEAKER_PORT) & 0xfc, PC_SPEAKER_PORT);
83 }
84
85 /**
86 * Use the PC speaker to create a tone/beep of the specified frequency
87 * and duration.
88 *
89 * Wait for a short amount of time after the beep to make it distinguishable
90 * from the next beep (if any).
91 *
92 * @param freq The frequency of the tone/beep.
93 * @param duration The duration of the tone/beep in milliseconds.
94 */
speaker_tone(u16 freq,unsigned int duration)95 void speaker_tone(u16 freq, unsigned int duration)
96 {
97 speaker_enable(freq);
98 mdelay(duration);
99 speaker_disable();
100 mdelay(100);
101 }
102