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标题: RT-Thread Audio - 1. 音频框架的分析 [打印本页]
作者: sunsili    时间: 2021-12-9 13:53
标题: RT-Thread Audio - 1. 音频框架的分析
本帖最后由 sunsili 于 2021-12-9 13:59 编辑

RT-Thread Audio - 1. 音频框架的分析

Github 上 RT-Thread 源码最新更新了关于 Audio 驱动相关的部分，让上层和底层都开发和编程简单了，不过对于大部分的开发者来说还不太熟悉这套框架的，那么笔者就这次编写音频驱动给大家分析下代码框架。

这里会先贴一张框架图，整个帖子都是笔者在编写开发过程中写的，可能有格式和错误，最终全部更新完毕后会整理整个系列的帖子。

1. RT-Thread 音频架构图



2. RT-Thread 音频框架的调用逻辑关系图(建议右键大图)



3. RT-Thread 音频应用代码模板(以wavplay为例)

https://github.com/RT-Thread-packages/wavplayer

4. RT-Thread 音频驱动代码模板

  1. #include "drv_sound.h"
  2. #include "drv_tina.h"
  3. #include "drivers/audio.h"

  5. #define DBG_TAG "drv_sound"
  6. #define DBG_LVL DBG_LOG
  7. #define DBG_COLOR
  8. #include

  10. #define TX_DMA_FIFO_SIZE (2048)

  12. struct temp_sound
  13. {
  14. struct rt_audio_device device;
  15. struct rt_audio_configure replay_config;
  16. int volume;
  17. rt_uint8_t *tx_fifo;
  18. };

  20. static rt_err_t getcaps(struct rt_audio_device *audio, struct rt_audio_caps *caps)
  21. {
  22. struct temp_sound *sound = RT_NULL;

  24. RT_ASSERT(audio != RT_NULL);
  25. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;

  27. return RT_EOK;
  28. }

  30. static rt_err_t configure(struct rt_audio_device *audio, struct rt_audio_caps *caps)
  31. {
  32. struct temp_sound *sound = RT_NULL;

  34. RT_ASSERT(audio != RT_NULL);
  35. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;

  37. return RT_EOK;
  38. }

  40. static rt_err_t init(struct rt_audio_device *audio)
  41. {
  42. struct temp_sound *sound = RT_NULL;

  44. RT_ASSERT(audio != RT_NULL);
  45. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;

  47. return RT_EOK;
  48. }

  50. static rt_err_t start(struct rt_audio_device *audio, int stream)
  51. {
  52. struct temp_sound *sound = RT_NULL;

  54. RT_ASSERT(audio != RT_NULL);
  55. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;

  57. return RT_EOK;
  58. }

  60. static rt_err_t stop(struct rt_audio_device *audio, int stream)
  61. {
  62. struct temp_sound *sound = RT_NULL;

  64. RT_ASSERT(audio != RT_NULL);
  65. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;

  67. return RT_EOK;
  68. }

  70. rt_size_t transmit(struct rt_audio_device *audio, const void *writeBuf, void *readBuf, rt_size_t size)
  71. {
  72. struct temp_sound *sound = RT_NULL;

  74. RT_ASSERT(audio != RT_NULL);
  75. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;

  77. return size;
  78. }

  80. static void buffer_info(struct rt_audio_device *audio, struct rt_audio_buf_info *info)
  81. {
  82. struct temp_sound *sound = RT_NULL;

  84. RT_ASSERT(audio != RT_NULL);
  85. sound = (struct temp_sound *)audio->parent.user_data;

  87. /**
  88. * TX_FIFO
  89. * +----------------+----------------+
  90. * | block1 | block2 |
  91. * +----------------+----------------+
  92. * \ block_size /
  93. */
  94. info->buffer = sound->tx_fifo;
  95. info->total_size = TX_DMA_FIFO_SIZE;
  96. info->block_size = TX_DMA_FIFO_SIZE / 2;
  97. info->block_count = 2;
  98. }

  100. static struct rt_audio_ops ops =
  101. {
  102. .getcaps = getcaps,
  103. .configure = configure,
  104. .init = init,
  105. .start = start,
  106. .stop = stop,
  107. .transmit = transmit,
  108. .buffer_info = buffer_info,
  109. };

  111. static int rt_hw_sound_init(void)
  112. {
  113. rt_uint8_t *tx_fifo = RT_NULL;
  114. static struct temp_sound sound = {0};

  116. /* 分配 DMA 搬运 buffer */
  117. tx_fifo = rt_calloc(1, TX_DMA_FIFO_SIZE);
  118. if(tx_fifo == RT_NULL)
  119. {
  120. return -RT_ENOMEM;
  121. }

  123. sound.tx_fifo = tx_fifo;

  125. /* 注册声卡放音驱动 */
  126. sound.device.ops = &ops;
  127. rt_audio_register(&sound.device, "sound0", RT_DEVICE_FLAG_WRONLY, &sound);

  129. return RT_EOK;
  130. }
  131. INIT_DEVICE_EXPORT(rt_hw_sound_init);
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5. 代码分析

待后续补充。。。

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