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Add SOF callback function for feedback value determination in uac - wip!

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This commit is contained in:
Reinhard Panhuber
2022-03-14 20:40:33 +01:00
parent 606f932d92
commit f212899b54
5 changed files with 156 additions and 9 deletions
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83
src/class/audio/audio_device.c
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@@ -306,6 +306,13 @@ typedef struct
#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP
uint32_t fb_val; // Feedback value for asynchronous mode (in 16.16 format).
#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR
uint8_t n_frames; // Number of (micro)frames used to estimate feedback value
uint8_t n_frames_current; // Current (micro)frame number
uint32_t feeback_param_factor; // TODO: Set this value within some new tud_audio_set_feedback_params_fm_fs function as feeback_param_factor = f_s / (f_cpu * n_frames)!
#endif
#endif
#endif
@@ -421,6 +428,10 @@ static inline uint8_t tu_desc_subtype(void const* desc)
}
#endif
#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR
static bool tud_audio_n_fb_set(uint8_t func_id, uint32_t feedback);
#endif
bool tud_audio_n_mounted(uint8_t func_id)
{
TU_VERIFY(func_id < CFG_TUD_AUDIO);
@@ -1658,6 +1669,11 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const *
{
audio->ep_fb = ep_addr;
#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR
usbd_sof_enable(rhport, true); // Enable SOF interrupt
audio->n_frames_current = 0;
#endif
// Invoke callback after ep_out is set
if (audio->ep_out != 0)
{
@@ -1682,6 +1698,23 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const *
p_desc = tu_desc_next(p_desc);
}
// Disable SOF interrupt if no driver has any enabled feedback EP
#if CFG_TUD_AUDIO_ENABLE_EP_OUT && CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP && CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR
bool disable = true;
for(uint8_t i=0; i < CFG_TUD_AUDIO; i++)
{
if (_audiod_fct[i].ep_fb != 0)
{
disable = false;
}
}
if (disable) usbd_sof_enable(rhport, false);
#endif
tud_control_status(rhport, p_request);
return true;
@@ -1970,6 +2003,52 @@ bool audiod_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint3
return false;
}
#if CFG_TUD_AUDIO_ENABLE_EP_OUT && CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP && CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR
bool tud_audio_set_feedback_params_fm_fs(uint8_t func_id, uint32_t f_m, uint32_t f_s)
{
audiod_function_t* audio = &_audiod_fct[func_id];
uint8_t n_frame = 1; // TODO: finalize that
audio->n_frames = n_frame;
audio->feeback_param_factor = f_s / f_m / n_frame; // TODO: Check the 16.16 precision!
return true;
}
#endif
void audiod_sof (uint8_t rhport, uint32_t frame_count)
{
(void) rhport;
(void) frame_count;
#if CFG_TUD_AUDIO_ENABLE_EP_OUT && CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP && CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR
// Determine feedback value - The feedback method is described in 5.12.4.2 of the USB 2.0 spec
// Boiled down, the feedback value Ff = n_samples / (micro)frame.
// Since an accuracy of less than 1 Sample / second is desired, at least n_frames = ceil(2^K * f_s / f_cpu) frames need to be measured, where K = 10 for full speed and K = 13 for high speed, f_s is the sampling frequency e.g. 48 kHz and f_cpu is the cpu clock frequency e.g. 100 MHz (or any other master clock whose clock count is available and locked to f_s)
// The update interval in the (4.10.2.1) Feedback Endpoint Descriptor must be less or equal to 2^(K - P), where P = min( ceil(log2(f_cpu / f_s)), K)
// Ff = n_cycles / n_frames * f_s / f_cpu in 16.16 format, where n_cycles are the number of CPU cycles within n_frames
// Iterate over audio functions and set feedback value
for(uint8_t i=0; i < CFG_TUD_AUDIO; i++)
{
audiod_function_t* audio = &_audiod_fct[i];
if (audio->ep_fb != 0)
{
audio->n_frames_current++;
if (audio->n_frames_current == audio->n_frames)
{
uint32_t n_cylces = tud_audio_n_get_fm_n_cycles_cb(rhport, audio->ep_fb);
uint32_t feedback = n_cylces * audio->feeback_param_factor;
tud_audio_n_fb_set(i, feedback);
audio->n_frames_current = 0;
}
}
}
#endif
}
bool tud_audio_buffer_and_schedule_control_xfer(uint8_t rhport, tusb_control_request_t const * p_request, void* data, uint16_t len)
{
// Handles only sending of data not receiving
@@ -2247,7 +2326,11 @@ static void audiod_parse_for_AS_params(audiod_function_t* audio, uint8_t const *
#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP
#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR
static bool tud_audio_n_fb_set(uint8_t func_id, uint32_t feedback)
#else
bool tud_audio_n_fb_set(uint8_t func_id, uint32_t feedback)
#endif
{
TU_VERIFY(func_id < CFG_TUD_AUDIO && _audiod_fct[func_id].p_desc != NULL);