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