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/*
*
* Copyright (C) 2007 Uwe Hermann <uwe@hermann-uwe.de>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Datasheet:
* - Name: 82C54 CHMOS Programmable Interval Timer
* - PDF: http://www.intel.com/design/archives/periphrl/docs/23124406.pdf
* - Order number: 231244-006
*/
#include <libpayload.h>
#define I82C54_CONTROL_WORD_REGISTER 0x43 /* Write-only. */
#define I82C54_COUNTER0 0x40
#define I82C54_COUNTER1 0x41
#define I82C54_COUNTER2 0x42
#define PC_SPEAKER_PORT 0x61
/**
* Use the PC speaker to create a tone/sound of the specified frequency.
*
* The Intel 82C54 CHMOS Programmable Interval Timer (PIT) provides a
* superset of the functions of the original Intel 8253/8254 PIT. It has
* three programmable counters/timers (counter 0, 1, and 2). Counter 2 can
* be used to generate tones/sounds of various frequencies and duration.
*
* See also:
* - http://en.wikipedia.org/wiki/Pc_speaker
* - http://en.wikipedia.org/wiki/Intel_8253
*
* @param freq The frequency of the tone.
*/
void speaker_enable(u16 freq)
{
u16 reg16 = 1193180 / freq;
/* Select counter 2. Read/write LSB first, then MSB. Use mode 3
(square wave generator). Use a 16bit binary counter. */
outb(0xb6, I82C54_CONTROL_WORD_REGISTER);
/* Set the desired tone frequency. */
outb((u8)(reg16 & 0x00ff), I82C54_COUNTER2); /* LSB. */
outb((u8)(reg16 >> 8), I82C54_COUNTER2); /* MSB. */
/* Enable the PC speaker (set bits 0 and 1). */
outb(inb(PC_SPEAKER_PORT) | 0x03, PC_SPEAKER_PORT);
}
/**
* Disable the PC speaker.
*/
void speaker_disable(void)
{
/* Disable the PC speaker (clear bits 0 and 1). */
outb(inb(PC_SPEAKER_PORT) & 0xfc, PC_SPEAKER_PORT);
}
/**
* Use the PC speaker to create a tone/beep of the specified frequency
* and duration.
*
* Wait for a short amount of time after the beep to make it distinguishable
* from the next beep (if any).
*
* @param freq The frequency of the tone/beep.
* @param duration The duration of the tone/beep in milliseconds.
*/
void speaker_tone(u16 freq, unsigned int duration)
{
speaker_enable(freq);
mdelay(duration);
speaker_disable();
mdelay(100);
}
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