1  /*
  2   *
  3   * Copyright (C) 2007 Uwe Hermann <uwe@hermann-uwe.de>
  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   */
 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   */
 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   */
 95  void speaker_tone(u16 freq, unsigned int duration)
 96  {
 97  	speaker_enable(freq);
 98  	mdelay(duration);
 99  	speaker_disable();
100  	mdelay(100);
101  }