NetBSD/sys/dev/audiobell.c
bjh21 9556e4209d Simple code to provide a console bell through a generic audio device, for
systems that don't have a dedicated feeper.  It's up to MD code to enable
this by having the "audiobell" attribute and calling audiobell() at the
appropriate moment.

Code for making noise in the kernel from Richard Earnshaw.  Simple synthesizer
design from the RISC OS Programmer's Reference manual.
2004-01-17 20:55:59 +00:00

171 lines
5.4 KiB
C

/* $NetBSD: audiobell.c,v 1.1 2004/01/17 20:55:59 bjh21 Exp $ */
/*
* Copyright (c) 1999 Richard Earnshaw
* Copyright (c) 2004 Ben Harris
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the RiscBSD team.
* 4. 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 ``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 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.
*/
#include <sys/types.h>
__KERNEL_RCSID(0, "$NetBSD: audiobell.c,v 1.1 2004/01/17 20:55:59 bjh21 Exp $");
#include <sys/audioio.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/null.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <dev/audio_if.h>
#include <dev/audiobellvar.h>
extern dev_type_open(audioopen);
extern dev_type_write(audiowrite);
extern dev_type_close(audioclose);
/* Convert a %age volume to an amount to add to u-law values */
/* XXX Probably highly inaccurate -- should be regenerated */
static const uint8_t volmap[] = {
0x7f, 0x67, 0x5b, 0x53, 0x49, 0x45, 0x41, 0x3e, 0x3a, 0x38,
0x36, 0x32, 0x30, 0x2f, 0x2e, 0x2c, 0x2b, 0x2a, 0x28, 0x27,
0x26, 0x25, 0x23, 0x22, 0x21, 0x1f, 0x1f, 0x1e, 0x1e, 0x1d,
0x1c, 0x1c, 0x1b, 0x1a, 0x1a, 0x19, 0x18, 0x18, 0x17, 0x17,
0x16, 0x15, 0x15, 0x14, 0x13, 0x13, 0x12, 0x11, 0x11, 0x10,
0x0f, 0x0f, 0x0f, 0x0f, 0x0e, 0x0e, 0x0e, 0x0d, 0x0d, 0x0d,
0x0c, 0x0c, 0x0c, 0x0b, 0x0b, 0x0b, 0x0a, 0x0a, 0x0a, 0x09,
0x09, 0x09, 0x08, 0x08, 0x08, 0x07, 0x07, 0x07, 0x07, 0x06,
0x06, 0x06, 0x05, 0x05, 0x05, 0x04, 0x04, 0x04, 0x03, 0x03,
0x03, 0x02, 0x02, 0x02, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00,
0x00
};
/* 1/4 cycle sine wave in u-law */
/* XXX Probably highly inaccurate -- should be regenerated */
static const uint8_t sinewave[] = {
0xff, 0xd3, 0xc5, 0xbc, 0xb6, 0xb0, 0xad, 0xaa,
0xa7, 0xa3, 0xa0, 0x9e, 0x9d, 0x9b, 0x9a, 0x98,
0x97, 0x96, 0x94, 0x93, 0x91, 0x90, 0x8f, 0x8e,
0x8e, 0x8d, 0x8c, 0x8c, 0x8b, 0x8b, 0x8a, 0x89,
0x89, 0x88, 0x88, 0x87, 0x87, 0x86, 0x86, 0x85,
0x85, 0x84, 0x84, 0x84, 0x83, 0x83, 0x83, 0x82,
0x82, 0x82, 0x81, 0x81, 0x81, 0x81, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80,
};
static inline uint8_t
audiobell_ulawscale(uint8_t val, uint8_t vol)
{
uint8_t result;
result = val + vol;
/* Spot underflow and just return silence */
if ((result ^ val) & 0x80)
return 0x7f;
return result;
}
static inline void
audiobell_expandwave(uint8_t *buf, int volume)
{
u_int i;
int uvol;
KASSERT(volume >= 0 && volume <= 100);
uvol = volmap[volume];
for (i = 0; i < 65; i++)
buf[i] = audiobell_ulawscale(sinewave[i], uvol);
for (i = 65; i < 128; i++)
buf[i] = buf[128 - i];
for (i = 128; i < 256; i++)
buf[i] = buf[i - 128] ^ 0x80;
}
/*
* The algorithm here is based on that described in the RISC OS Programmer's
* Reference Manual (pp1624--1628).
*/
static inline int
audiobell_synthesize(uint8_t *buf, u_int pitch, u_int period, u_int volume)
{
uint8_t *wave;
uint16_t phase;
MALLOC(wave, uint8_t *, 256, M_TEMP, M_WAITOK);
if (wave == NULL) return -1;
audiobell_expandwave(wave, volume);
pitch = pitch * 65536 / 8000;
period = period * 8; /* 8000 / 1000 */
phase = 0;
for (; period != 0; period--) {
*buf++ = wave[phase >> 8];
phase += pitch;
}
FREE(wave, M_TEMP);
return 0;
}
void
audiobell(void *arg, u_int pitch, u_int period, u_int volume, int poll)
{
struct device *audio = arg;
uint8_t *buf;
struct uio auio;
struct iovec aiov;
/* The audio system isn't built for polling. */
if (poll) return;
/* If not configured, we can't beep. */
if (audioopen(AUDIO_DEVICE | audio->dv_unit, FWRITE, 0, NULL) != 0)
return;
buf = malloc(period * 8, M_TEMP, M_WAITOK);
if (buf == NULL) goto out;
if (audiobell_synthesize(buf, pitch, period, volume) != 0) goto out;
aiov.iov_base = (caddr_t)buf;
aiov.iov_len = period * 8;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = 0;
auio.uio_resid = period * 8;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = UIO_WRITE;
auio.uio_procp = NULL;
audiowrite(AUDIO_DEVICE | audio->dv_unit, &auio, 0);
out:
if (buf != NULL) free(buf, M_TEMP);
audioclose(AUDIO_DEVICE | audio->dv_unit, FWRITE, 0, NULL);
}