e5ab6faf |
1 | /* sound output via OSS */ |
2 | #include <stdio.h> |
3 | #include <sys/types.h> |
4 | #include <sys/stat.h> |
5 | #include <fcntl.h> |
6 | #include <sys/ioctl.h> |
7 | #include <sys/soundcard.h> |
8 | #include <unistd.h> |
9 | |
10 | #include "sndout_oss.h" |
11 | |
12 | static int sounddev = -1, mixerdev = -1; |
13 | |
14 | int sndout_oss_init(void) |
15 | { |
16 | if (mixerdev >= 0) close(mixerdev); |
17 | mixerdev = open("/dev/mixer", O_RDWR); |
18 | if (mixerdev == -1) |
19 | { |
20 | perror("open(\"/dev/mixer\")"); |
21 | } |
22 | |
23 | return 0; |
24 | } |
25 | |
26 | |
27 | int sndout_oss_start(int rate, int bits, int stereo) |
28 | { |
29 | static int s_oldrate = 0, s_oldbits = 0, s_oldstereo = 0; |
30 | int frag = 0, bsize, buffers, ret; |
31 | |
32 | // if no settings change, we don't need to do anything, |
33 | // since audio is never stopped |
34 | if (rate == s_oldrate && s_oldbits == bits && s_oldstereo == stereo) |
35 | return 0; |
36 | |
37 | if (sounddev >= 0) close(sounddev); |
38 | sounddev = open("/dev/dsp", O_WRONLY|O_ASYNC); |
39 | if (sounddev == -1) |
40 | { |
41 | perror("open(\"/dev/dsp\")"); |
42 | return -1; |
43 | } |
44 | |
45 | // calculate buffer size |
46 | // this is tuned for GP2X |
47 | buffers = 16; |
48 | bsize = rate / 32; |
49 | if (rate > 22050) { bsize*=4; buffers*=2; } |
50 | while ((bsize>>=1)) frag++; |
51 | frag |= buffers<<16; // 16 buffers |
52 | ret = ioctl(sounddev, SNDCTL_DSP_SETFRAGMENT, &frag); |
53 | if (ret) perror("SNDCTL_DSP_SETFRAGMENT failed"); |
54 | |
55 | ret = ioctl(sounddev, SNDCTL_DSP_STEREO, &stereo); |
56 | ret |= ioctl(sounddev, SNDCTL_DSP_SETFMT, &bits); |
57 | ret |= ioctl(sounddev, SNDCTL_DSP_SPEED, &rate); |
58 | if (ret) printf("failed to set audio format\n"); |
59 | usleep(192*1024); |
60 | |
61 | printf("gp2x_set_sound: %i/%ibit/%s, %i buffers of %i bytes\n", |
62 | rate, bits, stereo?"stereo":"mono", frag>>16, 1<<(frag&0xffff)); |
63 | |
64 | s_oldrate = rate; s_oldbits = bits; s_oldstereo = stereo; |
65 | return 0; |
66 | } |
67 | |
68 | |
69 | int sndout_oss_write(const void *buff, int len) |
70 | { |
71 | return write(sounddev, buff, len); |
72 | } |
73 | |
74 | |
75 | void sndout_oss_sync(void) |
76 | { |
77 | ioctl(sounddev, SOUND_PCM_SYNC, 0); |
78 | } |
79 | |
80 | |
81 | void sndout_oss_setvol(int l, int r) |
82 | { |
83 | if (mixerdev < 0) return; |
84 | |
85 | l=l<0?0:l; l=l>255?255:l; r=r<0?0:r; r=r>255?255:r; |
86 | l<<=8; l|=r; |
87 | ioctl(mixerdev, SOUND_MIXER_WRITE_PCM, &l); /*SOUND_MIXER_WRITE_VOLUME*/ |
88 | } |
89 | |
90 | |
91 | void sndout_oss_exit(void) |
92 | { |
93 | if (sounddev >= 0) close(sounddev); sounddev = -1; |
94 | if (mixerdev >= 0) close(mixerdev); mixerdev = -1; |
95 | } |
96 | |