1 /*-
2 * Copyright (c) 2021 Hans Petter Selasky <hselasky@freebsd.org>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 #include <sys/soundcard.h>
27
28 #include <err.h>
29 #include <errno.h>
30 #include <fcntl.h>
31 #include <math.h>
32 #include <paths.h>
33 #include <stdbool.h>
34 #include <stdint.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <unistd.h>
39
40 #define SAMPLE_RATE_DEF 48000 /* hz */
41 #define SAMPLE_RATE_MAX 48000 /* hz */
42 #define SAMPLE_RATE_MIN 8000 /* hz */
43
44 #define DURATION_DEF 150 /* ms */
45 #define DURATION_MAX 2000 /* ms */
46 #define DURATION_MIN 50 /* ms */
47
48 #define GAIN_DEF 75
49 #define GAIN_MAX 100
50 #define GAIN_MIN 0
51
52 #define WAVE_POWER 1.25f
53
54 #define DEFAULT_HZ 440
55
56 #define DEFAULT_DEVICE _PATH_DEV "dsp"
57
58 static int frequency = DEFAULT_HZ;
59 static int duration_ms = DURATION_DEF;
60 static int sample_rate = SAMPLE_RATE_DEF;
61 static int gain = GAIN_DEF;
62 static const char *oss_dev = DEFAULT_DEVICE;
63 static bool background;
64
65 /*
66 * wave_function_16
67 *
68 * "phase" should be in the range [0.0f .. 1.0f>
69 * "power" should be in the range <0.0f .. 2.0f>
70 *
71 * The return value is in the range [-1.0f .. 1.0f]
72 */
73 static float
wave_function_16(float phase,float power)74 wave_function_16(float phase, float power)
75 {
76 uint16_t x = phase * (1U << 16);
77 float retval;
78 uint8_t num;
79
80 /* Handle special cases, if any */
81 switch (x) {
82 case 0xffff:
83 case 0x0000:
84 return (1.0f);
85 case 0x3fff:
86 case 0x4000:
87 case 0xBfff:
88 case 0xC000:
89 return (0.0f);
90 case 0x7FFF:
91 case 0x8000:
92 return (-1.0f);
93 default:
94 break;
95 }
96
97 /* Apply Gray coding */
98 for (uint16_t mask = 1U << 15; mask != 1; mask /= 2) {
99 if (x & mask)
100 x ^= (mask - 1);
101 }
102
103 /* Find first set bit */
104 for (num = 0; num != 14; num++) {
105 if (x & (1U << num)) {
106 num++;
107 break;
108 }
109 }
110
111 /* Initialize return value */
112 retval = 0.0;
113
114 /* Compute the rest of the power series */
115 for (; num != 14; num++) {
116 if (x & (1U << num)) {
117 retval = (1.0f - retval) / 2.0f;
118 retval = powf(retval, power);
119 } else {
120 retval = (1.0f + retval) / 2.0f;
121 retval = powf(retval, power);
122 }
123 }
124
125 /* Check if halfway */
126 if (x & (1ULL << 14))
127 retval = -retval;
128
129 return (retval);
130 }
131
132 static void
usage(void)133 usage(void)
134 {
135 fprintf(stderr, "Usage: %s [parameters]\n"
136 "\t" "-F <frequency in HZ, default %d Hz>\n"
137 "\t" "-D <duration in ms, from %d ms to %d ms, default %d ms>\n"
138 "\t" "-r <sample rate in HZ, from %d Hz to %d Hz, default %d Hz>\n"
139 "\t" "-d <OSS device (default %s)>\n"
140 "\t" "-g <gain from %d to %d, default %d>\n"
141 "\t" "-B Run in background\n"
142 "\t" "-h Show usage\n",
143 getprogname(),
144 DEFAULT_HZ,
145 DURATION_MIN, DURATION_MAX, DURATION_DEF,
146 SAMPLE_RATE_MIN, SAMPLE_RATE_MAX, SAMPLE_RATE_DEF,
147 DEFAULT_DEVICE,
148 GAIN_MIN, GAIN_MAX, GAIN_DEF);
149 exit(1);
150 }
151
152 int
main(int argc,char ** argv)153 main(int argc, char **argv)
154 {
155 int32_t *buffer;
156 size_t slope;
157 size_t size;
158 size_t off;
159 float a;
160 float d;
161 float p;
162 int c;
163 int f;
164
165 while ((c = getopt(argc, argv, "BF:D:r:g:d:h")) != -1) {
166 switch (c) {
167 case 'F':
168 frequency = strtol(optarg, NULL, 10);
169 break;
170 case 'D':
171 duration_ms = strtol(optarg, NULL, 10);
172 if (duration_ms < DURATION_MIN ||
173 duration_ms > DURATION_MAX)
174 usage();
175 break;
176 case 'r':
177 sample_rate = strtol(optarg, NULL, 10);
178 if (sample_rate < SAMPLE_RATE_MIN ||
179 sample_rate > SAMPLE_RATE_MAX)
180 usage();
181 break;
182 case 'g':
183 gain = strtol(optarg, NULL, 10);
184 if (gain < GAIN_MIN ||
185 gain > GAIN_MAX)
186 usage();
187 break;
188 case 'd':
189 oss_dev = optarg;
190 break;
191 case 'B':
192 background = true;
193 break;
194 default:
195 usage();
196 break;
197 }
198 }
199
200 if (background && daemon(0, 0) != 0)
201 errx(1, "daemon(0,0) failed");
202
203 f = open(oss_dev, O_WRONLY);
204 if (f < 0)
205 err(1, "Failed to open '%s'", oss_dev);
206
207 c = 1; /* mono */
208 if (ioctl(f, SOUND_PCM_WRITE_CHANNELS, &c) != 0)
209 errx(1, "ioctl SOUND_PCM_WRITE_CHANNELS(1) failed");
210
211 c = AFMT_S32_NE;
212 if (ioctl(f, SNDCTL_DSP_SETFMT, &c) != 0)
213 errx(1, "ioctl SNDCTL_DSP_SETFMT(AFMT_S32_NE) failed");
214
215 if (ioctl(f, SNDCTL_DSP_SPEED, &sample_rate) != 0)
216 errx(1, "ioctl SNDCTL_DSP_SPEED(%d) failed", sample_rate);
217
218 c = (2 << 16);
219 while ((1ULL << (c & 63)) < (size_t)(4 * sample_rate / 50))
220 c++;
221 if (ioctl(f, SNDCTL_DSP_SETFRAGMENT, &c))
222 errx(1, "ioctl SNDCTL_DSP_SETFRAGMENT(0x%x) failed", c);
223
224 if (ioctl(f, SNDCTL_DSP_GETODELAY, &c) != 0)
225 errx(1, "ioctl SNDCTL_DSP_GETODELAY failed");
226
227 size = ((sample_rate * duration_ms) + 999) / 1000;
228 buffer = malloc(sizeof(buffer[0]) * size);
229 if (buffer == NULL)
230 errx(1, "out of memory");
231
232 /* compute slope duration in samples */
233 slope = (DURATION_MIN * sample_rate) / 2000;
234
235 /* compute base gain */
236 a = powf(65536.0f, (float)gain / (float)GAIN_MAX) / 65536.0f;
237
238 /* set initial phase and delta */
239 p = 0;
240 d = (float)frequency / (float)sample_rate;
241
242 /* compute wave */
243 for (p = off = 0; off != size; off++, p += d) {
244 float sample;
245
246 p = p - floorf(p);
247 sample = a * wave_function_16(p, WAVE_POWER);
248
249 if (off < slope)
250 sample = sample * off / (float)slope;
251 else if (off > (size - slope))
252 sample = sample * (size - off - 1) / (float)slope;
253
254 buffer[off] = sample * 0x7fffff00;
255 }
256
257 if (write(f, buffer, size * sizeof(buffer[0])) !=
258 (ssize_t)(size * sizeof(buffer[0])))
259 errx(1, "failed writing to DSP device(%s)", oss_dev);
260
261 free(buffer);
262
263 /* wait for data to be written */
264 while (ioctl(f, SNDCTL_DSP_GETODELAY, &c) == 0) {
265 if (c == 0)
266 break;
267 usleep(10000);
268 }
269
270 /* wait for audio to go out */
271 usleep(50000);
272 close(f);
273
274 return (0);
275 }
276