Atlas - SDL_ps2audio.c
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1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2025 Sam Lantinga <[email protected]>
4
5  This software is provided 'as-is', without any express or implied
6  warranty.  In no event will the authors be held liable for any damages
7  arising from the use of this software.
8
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12
13  1. The origin of this software must not be misrepresented; you must not
14     claim that you wrote the original software. If you use this software
15     in a product, an acknowledgment in the product documentation would be
16     appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18     misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20*/
21#include "SDL_internal.h"
22
23#include "../SDL_sysaudio.h"
24#include "SDL_ps2audio.h"
25
26#include <kernel.h>
27#include <audsrv.h>
28#include <ps2_audio_driver.h>
29
30static bool PS2AUDIO_OpenDevice(SDL_AudioDevice *device)
31{
32    device->hidden = (struct SDL_PrivateAudioData *) SDL_calloc(1, sizeof(*device->hidden));
33    if (!device->hidden) {
34        return false;
35    }
36
37    // These are the native supported audio PS2 configs
38    switch (device->spec.freq) {
39    case 11025:
40    case 12000:
41    case 22050:
42    case 24000:
43    case 32000:
44    case 44100:
45    case 48000:
46        break;  // acceptable value, keep it
47    default:
48        device->spec.freq = 48000;
49        break;
50    }
51
52    device->sample_frames = 512;
53    device->spec.channels = device->spec.channels == 1 ? 1 : 2;
54    device->spec.format = device->spec.format == SDL_AUDIO_S8 ? SDL_AUDIO_S8 : SDL_AUDIO_S16;
55
56    struct audsrv_fmt_t format;
57    format.bits = device->spec.format == SDL_AUDIO_S8 ? 8 : 16;
58    format.freq = device->spec.freq;
59    format.channels = device->spec.channels;
60
61    device->hidden->channel = audsrv_set_format(&format);
62    audsrv_set_volume(MAX_VOLUME);
63
64    if (device->hidden->channel < 0) {
65        return SDL_SetError("Couldn't reserve hardware channel");
66    }
67
68    // Update the fragment size as size in bytes.
69    SDL_UpdatedAudioDeviceFormat(device);
70
71    /* Allocate the mixing buffer.  Its size and starting address must
72       be a multiple of 64 bytes.  Our sample count is already a multiple of
73       64, so spec->size should be a multiple of 64 as well. */
74    const int mixlen = device->buffer_size * NUM_BUFFERS;
75    device->hidden->rawbuf = (Uint8 *)SDL_aligned_alloc(64, mixlen);
76    if (!device->hidden->rawbuf) {
77        return SDL_SetError("Couldn't allocate mixing buffer");
78    }
79
80    SDL_memset(device->hidden->rawbuf, device->silence_value, mixlen);
81    for (int i = 0; i < NUM_BUFFERS; i++) {
82        device->hidden->mixbufs[i] = &device->hidden->rawbuf[i * device->buffer_size];
83    }
84
85    return true;
86}
87
88static bool PS2AUDIO_PlayDevice(SDL_AudioDevice *device, const Uint8 *buffer, int buflen)
89{
90    // this returns number of bytes accepted or a negative error. We assume anything other than buflen is a fatal error.
91    return (audsrv_play_audio((char *)buffer, buflen) == buflen);
92}
93
94static bool PS2AUDIO_WaitDevice(SDL_AudioDevice *device)
95{
96    audsrv_wait_audio(device->buffer_size);
97    return true;
98}
99
100static Uint8 *PS2AUDIO_GetDeviceBuf(SDL_AudioDevice *device, int *buffer_size)
101{
102    Uint8 *buffer = device->hidden->mixbufs[device->hidden->next_buffer];
103    device->hidden->next_buffer = (device->hidden->next_buffer + 1) % NUM_BUFFERS;
104    return buffer;
105}
106
107static void PS2AUDIO_CloseDevice(SDL_AudioDevice *device)
108{
109    if (device->hidden) {
110        if (device->hidden->channel >= 0) {
111            audsrv_stop_audio();
112            device->hidden->channel = -1;
113        }
114
115        if (device->hidden->rawbuf) {
116            SDL_aligned_free(device->hidden->rawbuf);
117            device->hidden->rawbuf = NULL;
118        }
119        SDL_free(device->hidden);
120        device->hidden = NULL;
121    }
122}
123
124static void PS2AUDIO_ThreadInit(SDL_AudioDevice *device)
125{
126    /* Increase the priority of this audio thread by 1 to put it
127       ahead of other SDL threads. */
128    const int32_t thid = GetThreadId();
129    ee_thread_status_t status;
130    if (ReferThreadStatus(thid, &status) == 0) {
131        ChangeThreadPriority(thid, status.current_priority - 1);
132    }
133}
134
135static void PS2AUDIO_Deinitialize(void)
136{
137    deinit_audio_driver();
138}
139
140static bool PS2AUDIO_Init(SDL_AudioDriverImpl *impl)
141{
142    if (init_audio_driver() < 0) {
143        return false;
144    }
145
146    impl->OpenDevice = PS2AUDIO_OpenDevice;
147    impl->PlayDevice = PS2AUDIO_PlayDevice;
148    impl->WaitDevice = PS2AUDIO_WaitDevice;
149    impl->GetDeviceBuf = PS2AUDIO_GetDeviceBuf;
150    impl->CloseDevice = PS2AUDIO_CloseDevice;
151    impl->ThreadInit = PS2AUDIO_ThreadInit;
152    impl->Deinitialize = PS2AUDIO_Deinitialize;
153    impl->OnlyHasDefaultPlaybackDevice = true;
154    return true; // this audio target is available.
155}
156
157AudioBootStrap PS2AUDIO_bootstrap = {
158    "ps2", "PS2 audio driver", PS2AUDIO_Init, false, false
159};
160
[FILE END]
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