685ae2d55a
221220000 张三 Linux zzy 5.15.146.1-microsoft-standard-WSL2 #1 SMP Thu Jan 11 04:09:03 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux 21:14:43 up 3 days, 16:20, 1 user, load average: 0.53, 0.40, 0.61
106 lines
3.1 KiB
C
106 lines
3.1 KiB
C
/***************************************************************************************
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* Copyright (c) 2014-2022 Zihao Yu, Nanjing University
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*
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* NEMU is licensed under Mulan PSL v2.
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* You can use this software according to the terms and conditions of the Mulan PSL v2.
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* You may obtain a copy of Mulan PSL v2 at:
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* http://license.coscl.org.cn/MulanPSL2
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*
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* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
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* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
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* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
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*
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* See the Mulan PSL v2 for more details.
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***************************************************************************************/
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#include <common.h>
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#include <device/map.h>
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#include <SDL2/SDL.h>
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enum {
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reg_freq,
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reg_channels,
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reg_samples,
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reg_sbuf_size,
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reg_init,
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reg_count,
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nr_reg
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};
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static uint8_t *sbuf = NULL;
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static uint32_t *audio_base = NULL;
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static uint32_t pos_read = 0;
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#define MIN(a, b) ((a) < (b) ? (a) : (b))
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static void audio_callback(void *userdata, uint8_t *stream, int len) {
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uint32_t count = audio_base[reg_count];
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uint32_t read_cnt = MIN(count, len);
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uint32_t to_end_cnt = audio_base[reg_sbuf_size] - pos_read;
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int32_t out_bound_cnt = read_cnt - to_end_cnt;
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memset(stream, 0, len);
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if (out_bound_cnt > 0) {
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memcpy(stream, sbuf + pos_read, to_end_cnt);
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memcpy(stream + to_end_cnt, sbuf, out_bound_cnt);
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} else {
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memcpy(stream, sbuf + pos_read, read_cnt);
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}
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pos_read += read_cnt;
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pos_read %= audio_base[reg_sbuf_size];
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// if (len > read_cnt) memset(stream + read_cnt, 0, len - read_cnt);
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audio_base[reg_count] -= read_cnt;
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}
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static inline void init_audio_dev() {
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SDL_AudioSpec s = {};
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s.format = AUDIO_S16SYS; // 假设系统中音频数据的格式总是使用16位有符号数来表示
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s.userdata = NULL; // 不使用
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s.freq = audio_base[reg_freq];
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s.channels = audio_base[reg_channels];
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s.samples = audio_base[reg_samples];
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s.callback = audio_callback;
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assert(SDL_InitSubSystem(SDL_INIT_AUDIO) == 0);
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assert(SDL_OpenAudio(&s, NULL) == 0);
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SDL_PauseAudio(0);
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}
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static void audio_io_handler(uint32_t offset, int len, bool is_write) {
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assert(offset % 4 == 0);
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int idx = offset / 4;
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switch (idx) {
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case reg_freq:
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case reg_channels:
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case reg_samples:
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break;
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case reg_sbuf_size:
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assert(is_write == false);
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break;
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case reg_init:
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if (is_write && audio_base[reg_init] != 0) {
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init_audio_dev();
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}
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break;
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case reg_count:
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// TODO: must be add a lock here
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break;
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default:
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assert(0);
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}
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}
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void init_audio() {
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uint32_t space_size = sizeof(uint32_t) * nr_reg;
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audio_base = (uint32_t *)new_space(space_size);
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audio_base[reg_sbuf_size] = CONFIG_SB_SIZE;
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audio_base[reg_init] = 0;
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#ifdef CONFIG_HAS_PORT_IO
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add_pio_map ("audio", CONFIG_AUDIO_CTL_PORT, audio_base, space_size, audio_io_handler);
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#else
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add_mmio_map("audio", CONFIG_AUDIO_CTL_MMIO, audio_base, space_size, audio_io_handler);
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#endif
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sbuf = (uint8_t *)new_space(CONFIG_SB_SIZE);
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add_mmio_map("audio-sbuf", CONFIG_SB_ADDR, sbuf, CONFIG_SB_SIZE, NULL);
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}
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