RT-Thread Audio - 1. 音频框架的分析

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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"
   
4. 
   
5. #define DBG_TAG "drv_sound"
   
6. #define DBG_LVL DBG_LOG
   
7. #define DBG_COLOR
   
8. #include
   
9. 
   
10. #define TX_DMA_FIFO_SIZE (2048)
    
11. 
    
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. };
    
19. 
    
20. static rt_err_t getcaps(struct rt_audio_device *audio, struct rt_audio_caps *caps)
    
21. {
    
22. struct temp_sound *sound = RT_NULL;
    
23. 
    
24. RT_ASSERT(audio != RT_NULL);
    
25. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;
    
26. 
    
27. return RT_EOK;
    
28. }
    
29. 
    
30. static rt_err_t configure(struct rt_audio_device *audio, struct rt_audio_caps *caps)
    
31. {
    
32. struct temp_sound *sound = RT_NULL;
    
33. 
    
34. RT_ASSERT(audio != RT_NULL);
    
35. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;
    
36. 
    
37. return RT_EOK;
    
38. }
    
39. 
    
40. static rt_err_t init(struct rt_audio_device *audio)
    
41. {
    
42. struct temp_sound *sound = RT_NULL;
    
43. 
    
44. RT_ASSERT(audio != RT_NULL);
    
45. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;
    
46. 
    
47. return RT_EOK;
    
48. }
    
49. 
    
50. static rt_err_t start(struct rt_audio_device *audio, int stream)
    
51. {
    
52. struct temp_sound *sound = RT_NULL;
    
53. 
    
54. RT_ASSERT(audio != RT_NULL);
    
55. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;
    
56. 
    
57. return RT_EOK;
    
58. }
    
59. 
    
60. static rt_err_t stop(struct rt_audio_device *audio, int stream)
    
61. {
    
62. struct temp_sound *sound = RT_NULL;
    
63. 
    
64. RT_ASSERT(audio != RT_NULL);
    
65. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;
    
66. 
    
67. return RT_EOK;
    
68. }
    
69. 
    
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;
    
73. 
    
74. RT_ASSERT(audio != RT_NULL);
    
75. sound = (struct temp_sound *)audio->parent.user_data; (void)sound;
    
76. 
    
77. return size;
    
78. }
    
79. 
    
80. static void buffer_info(struct rt_audio_device *audio, struct rt_audio_buf_info *info)
    
81. {
    
82. struct temp_sound *sound = RT_NULL;
    
83. 
    
84. RT_ASSERT(audio != RT_NULL);
    
85. sound = (struct temp_sound *)audio->parent.user_data;
    
86. 
    
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. }
    
99. 
    
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. };
     
110. 
     
111. static int rt_hw_sound_init(void)
     
112. {
     
113. rt_uint8_t *tx_fifo = RT_NULL;
     
114. static struct temp_sound sound = {0};
     
115. 
     
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. }
     
122. 
     
123. sound.tx_fifo = tx_fifo;
     
124. 
     
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);
     
128. 
     
129. return RT_EOK;
     
130. }
     
131. INIT_DEVICE_EXPORT(rt_hw_sound_init);

复制代码

5. 代码分析

待后续补充。。。

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