From ff2dc0a5471c3166a1995cc2abb5f42a8a9ab035 Mon Sep 17 00:00:00 2001 From: Reinhard Panhuber Date: Sun, 20 Mar 2022 11:21:33 +0100 Subject: [PATCH] Streamline feedback calc, find fb interval from descriptors, inc. checks --- src/class/audio/audio_device.c | 195 ++++++++++++++++++--------------- src/class/audio/audio_device.h | 28 ++++- 2 files changed, 135 insertions(+), 88 deletions(-) diff --git a/src/class/audio/audio_device.c b/src/class/audio/audio_device.c index a815f7557..b97155823 100644 --- a/src/class/audio/audio_device.c +++ b/src/class/audio/audio_device.c @@ -305,18 +305,29 @@ typedef struct #endif #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 + uint32_t fb_val; // Feedback value for asynchronous mode (in 16.16 format). +#endif #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 n_cycles_old; // Old cycle count - union { - uint32_t i; - float f; - } feedback_param_factor_N; // Numerator of feedback parameter coefficient - uint32_t feedback_param_factor_D; // Denominator of feedback parameter coefficient - uint32_t * feedback_param_p_cycle_count; // Pointer to cycle counter + volatile uint32_t fb_val; // Feedback value for asynchronous mode (in 16.16 format). + uint8_t fb_n_frames; // Number of (micro)frames used to estimate feedback value + volatile uint8_t fb_n_frames_current; // Current (micro)frame number + volatile uint32_t fb_n_cycles_old; // Old cycle count + uint32_t * fb_param_p_cycle_count; // Pointer to cycle counter + +#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE == CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_POWER_OF_TWO_SHIFT + uint8_t fb_power_of_two_val; +#endif + +#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE == CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FLOAT + float fb_float_val; +#endif + +#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE == CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FIXED_POINT + uint64_t fb_param_factor_N; // Numerator of feedback parameter coefficient + uint64_t fb_param_factor_D; // Denominator of feedback parameter coefficient +#endif #endif #endif @@ -1527,7 +1538,7 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const * tu_fifo_clear(&audio->tx_supp_ff[cnt]); } #endif - + // Invoke callback - can be used to stop data sampling if (tud_audio_set_itf_close_EP_cb) TU_VERIFY(tud_audio_set_itf_close_EP_cb(rhport, p_request)); @@ -1560,7 +1571,7 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const * // Close corresponding feedback EP #if CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP usbd_edpt_close(rhport, audio->ep_fb); - audio->ep_fb = 0; // Necessary? + audio->ep_fb = 0; #endif } #endif @@ -1677,8 +1688,9 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const * #if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR usbd_sof_enable(rhport, true); // Enable SOF interrupt - audio->n_frames_current = 0; - audio->n_cycles_old = 0; + audio->fb_n_frames = desc_ep->bInterval; + audio->fb_n_frames_current = 0; + audio->fb_n_cycles_old = 0; #endif // Invoke callback after ep_out is set @@ -1711,12 +1723,12 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const * bool disable = true; for(uint8_t i=0; i < CFG_TUD_AUDIO; i++) + { + if (_audiod_fct[i].ep_fb != 0) { - if (_audiod_fct[i].ep_fb != 0) - { - disable = false; - } + disable = false; } + } if (disable) usbd_sof_enable(rhport, false); @@ -2011,40 +2023,56 @@ bool audiod_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint3 } #if CFG_TUD_AUDIO_ENABLE_EP_OUT && CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP && CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR -// f_s max is 2^19-1 = 524287 Hz -// n_frames_min is ceil(2^10 * f_s / f_m) for full speed and ceil(2^13 * f_s / f_m) for high speed -// f_m max is 2^29/(1 ms * n_frames) for full speed and 2^29/(125 us * n_frames) for high speed -bool tud_audio_set_feedback_params_fm_fs(uint8_t func_id, uint32_t f_m, uint32_t f_s, uint32_t * p_cycle_count, bool use_float) + +// This function must be called from the user within the tud_audio_set_itf_cb(rhport, p_request) callback function, where p_request needs to be checked as +// uint8_t const itf = tu_u16_low(p_request->wIndex); +// uint8_t const alt = tu_u16_low(p_request->wValue); +// such that tud_audio_set_fb_params() gets called with the parameters corresponding to the defined interface and alternate setting +// Also, start the main clock cycle counter (or reset its value) within tud_audio_set_itf_cb() +TU_ATTR_WEAK bool tud_audio_set_fb_params(uint8_t func_id, uint32_t f_m, uint32_t f_s, uint32_t * p_cycle_count) { audiod_function_t* audio = &_audiod_fct[func_id]; - audio->feedback_param_p_cycle_count = p_cycle_count; - uint8_t n_frame = 1; // TODO: finalize that - audio->n_frames = n_frame; + audio->fb_param_p_cycle_count = p_cycle_count; + // Check if frame interval is within sane limits + // The interval value audio->fb_n_frames was taken from the descriptors within audiod_set_interface() - - // Check if parameters reduce to a power of two shift i.e. is n_f * f_m / f_s a power of two? - if ((f_m % f_s) == 0 && tu_is_power_of_two(n_frame * f_m / f_s)) + // n_frames_min is ceil(2^10 * f_s / f_m) for full speed and ceil(2^13 * f_s / f_m) for high speed - this lower limit ensures the measures feedback value has sufficient precision + if ((TUSB_SPEED_FULL == tud_speed_get() && ((2^10 * f_s / f_m) + 1) > audio->fb_n_frames) || (TUSB_SPEED_HIGH == tud_speed_get() && ((2^13 * f_s / f_m) + 1) > audio->fb_n_frames)) { - audio->feedback_param_factor_N.i = 0; // zero marks power of two option - audio->feedback_param_factor_D = 16 - tu_log2(n_frame * f_m / f_s); + TU_LOG2(" UAC2 feedback interval too small\r\n"); TU_BREAKPOINT(); return false; } - else + + +#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE == CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_POWER_OF_TWO_SHIFT + // Check if parameters really allow for a power of two division + if ((f_m % f_s) != 0 || !tu_is_power_of_two(audio->fb_n_frames * f_m / f_s)) { - // Next best option is to use float if a FPU is available - this has to be enabled by the user - if (use_float) - { - audio->feedback_param_factor_N.f = (float)f_s / n_frame / f_m * (1 << 16); - audio->feedback_param_factor_D = 0; // non zero marks float option - } - else - { - // Neither a power of two or floats - use fixed point number - audio->feedback_param_factor_N.i = f_s << 13; - audio->feedback_param_factor_D = f_m * n_frame; - } + TU_LOG2(" FEEDBACK_DETERMINATION_MODE_POWER_OF_TWO_SHIFT not possible!\r\n"); TU_BREAKPOINT(); return false; } + audio->fb_power_of_two_val = 16 - tu_log2(audio->fb_n_frames * f_m / f_s); +#endif + +#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE == CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FLOAT + audio->fb_float_val = (float)f_s / audio->fb_n_frames / f_m * (1 << 16); +#endif + +#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE == CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FIXED_POINT + + // f_s max is 2^19-1 = 524287 Hz + // f_m max is 2^29/(1 ms * n_frames) for full speed and 2^29/(125 us * n_frames) for high speed, this means for f_m fitting in an uint32, n_frames must be < 125 for full speed and < 1000 for high speed (1000 does not fit into uint8 so the maximum possible value cannot even be reached by UAC2 - we don't need to check for it) + + if ((f_s > (2^19)-1) || (TUSB_SPEED_FULL == tud_speed_get() && (audio->fb_n_frames > 125))) + { + // If this check fails, not every thing is lost - you need to re-evaluate the scaling factors of the parameters such that the numbers fit into uint64 again. feedback = n_cycles * S_c / (n_frames * S_n) * f_s * S_s / (f_m * S_m). In the end S_c*S_s / (S_n * S_m) = 2^16 for a 16.16 fixed point precision. If you find something, define your own function of tud_audio_set_feedback_params_fm_fs() and audiod_sof() and use your values + TU_LOG2(" FEEDBACK_DETERMINATION_MODE_FIXED_POINT not possible!\r\n"); TU_BREAKPOINT(); return false; + } + + audio->fb_param_factor_N = (uint64_t)f_s << 13; + audio->fb_param_factor_D = (uint64_t)f_m * audio->fb_n_frames; +#endif + return true; } @@ -2053,54 +2081,47 @@ bool tud_audio_set_feedback_params_fm_fs(uint8_t func_id, uint32_t f_m, uint32_t void audiod_sof (uint8_t rhport, uint32_t frame_count) { (void) rhport; - (void) frame_count; + (void) frame_count; // frame_count is not used since some devices may not provide the frame count value #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_m) 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 + // Since an accuracy of less than 1 Sample / second is desired, at least n_frames = ceil(2^K * f_s / f_m) 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_m 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_m / f_s)), K) + // feedback = n_cycles / n_frames * f_s / f_m in 16.16 format, where n_cycles are the number of main clock cycles within fb_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) { - audiod_function_t* audio = &_audiod_fct[i]; - - if (audio->ep_fb != 0) + audio->fb_n_frames_current++; + if (audio->fb_n_frames_current == audio->fb_n_frames) { - audio->n_frames_current++; - if (audio->n_frames_current == audio->n_frames) - { - uint32_t n_cylces = *audio->feedback_param_p_cycle_count; - uint32_t feedback; + uint32_t n_cylces = *audio->fb_param_p_cycle_count; + uint32_t feedback; - if (audio->feedback_param_factor_N.i == 0) - { - // Power of two shift - feedback = n_cylces << audio->feedback_param_factor_D; - } - else - { - if (audio->feedback_param_factor_D == 0) - { - // Float computation - feedback = (uint32_t)(n_cylces * audio->feedback_param_factor_N.f); - } - else - { - // Fixed point computation - feedback = ((n_cylces - audio->n_cycles_old) << 3) * audio->feedback_param_factor_N.i / audio->feedback_param_factor_D; // feeback_param_factor_N has scaling factor of 13 bits, n_cycles 3 and feeback_param_factor_D 1, hence 16.16 precision - } - } +#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE == CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_POWER_OF_TWO_SHIFT + feedback = (n_cylces - audio->fb_n_cycles_old) << audio->fb_power_of_two_val; +#endif - tud_audio_n_fb_set(i, feedback); - audio->n_frames_current = 0; - audio->n_cycles_old = n_cylces; - } +#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE == CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FLOAT + feedback = (uint32_t)((float)(n_cylces - audio->fb_n_cycles_old) * audio->fb_float_val); +#endif + +#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE == CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FIXED_POINT + feedback = ((n_cylces - audio->fb_n_cycles_old) << 3) * audio->fb_param_factor_N / audio->fb_param_factor_D; // feeback_param_factor_N has scaling factor of 13 bits, n_cycles 3 and feeback_param_factor_D 1, hence 16.16 precision +#endif + + tud_audio_n_fb_set(i, feedback); + audio->fb_n_frames_current = 0; + audio->fb_n_cycles_old = n_cylces; } } + } #endif } @@ -2299,6 +2320,16 @@ static bool audiod_verify_ep_exists(uint8_t ep, uint8_t *func_id) // Currently, only AS interfaces with an EP (in or out) are supposed to be parsed for! static void audiod_parse_for_AS_params(audiod_function_t* audio, uint8_t const * p_desc, uint8_t const * p_desc_end, uint8_t const as_itf) { +#if CFG_TUD_AUDIO_ENABLE_EP_IN && CFG_TUD_AUDIO_ENABLE_EP_OUT + if (as_itf != audio->ep_in_as_intf_num && as_itf != audio->ep_out_as_intf_num) return; // Abort, this interface has no EP, this driver does not support this currently +#endif +#if CFG_TUD_AUDIO_ENABLE_EP_IN && !CFG_TUD_AUDIO_ENABLE_EP_OUT + if (as_itf != audio->ep_in_as_intf_num) return; +#endif +#if !CFG_TUD_AUDIO_ENABLE_EP_IN && CFG_TUD_AUDIO_ENABLE_EP_OUT + if (as_itf != audio->ep_out_as_intf_num) return; +#endif + p_desc = tu_desc_next(p_desc); // Exclude standard AS interface descriptor of current alternate interface descriptor while (p_desc < p_desc_end) @@ -2309,16 +2340,6 @@ static void audiod_parse_for_AS_params(audiod_function_t* audio, uint8_t const * // Look for a Class-Specific AS Interface Descriptor(4.9.2) to verify format type and format and also to get number of physical channels if (tu_desc_type(p_desc) == TUSB_DESC_CS_INTERFACE && tu_desc_subtype(p_desc) == AUDIO_CS_AS_INTERFACE_AS_GENERAL) { -#if CFG_TUD_AUDIO_ENABLE_EP_IN && CFG_TUD_AUDIO_ENABLE_EP_OUT - if (as_itf != audio->ep_in_as_intf_num && as_itf != audio->ep_out_as_intf_num) break; // Abort loop, this interface has no EP, this driver does not support this currently -#endif -#if CFG_TUD_AUDIO_ENABLE_EP_IN && !CFG_TUD_AUDIO_ENABLE_EP_OUT - if (as_itf != audio->ep_in_as_intf_num) break; -#endif -#if !CFG_TUD_AUDIO_ENABLE_EP_IN && CFG_TUD_AUDIO_ENABLE_EP_OUT - if (as_itf != audio->ep_out_as_intf_num) break; -#endif - #if CFG_TUD_AUDIO_ENABLE_EP_IN if (as_itf == audio->ep_in_as_intf_num) { diff --git a/src/class/audio/audio_device.h b/src/class/audio/audio_device.h index 3645bda46..f1bb084d6 100644 --- a/src/class/audio/audio_device.h +++ b/src/class/audio/audio_device.h @@ -196,6 +196,25 @@ #define CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR 1 // 0 or 1 #endif +// Feeback calculation mode +#if CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_WITHIN_SOF_ISR + +#define CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_POWER_OF_TWO_SHIFT 1 +#define CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FLOAT 2 +#define CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FIXED_POINT 3 + +#ifndef CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE +#error You must tell the driver the feedback determination mode! Possible choices are: CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_POWER_OF_TWO_SHIFT, CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FLOAT, or CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FIXED_POINT! +#endif + +#ifdef CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE +#if (CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE != CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_POWER_OF_TWO_SHIFT && CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE != CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FLOAT && CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE != CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FIXED_POINT) +#error Unknown CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE. Possible choices are: CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_POWER_OF_TWO_SHIFT, CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FLOAT, or CFG_TUD_AUDIO_ENABLE_FEEDBACK_DETERMINATION_MODE_FIXED_POINT! +#endif +#endif + +#endif + // Audio interrupt control EP size - disabled if 0 #ifndef CFG_TUD_AUDIO_INT_CTR_EPSIZE_IN #define CFG_TUD_AUDIO_INT_CTR_EPSIZE_IN 0 // Audio interrupt control - if required - 6 Bytes according to UAC 2 specification (p. 74) @@ -487,7 +506,14 @@ TU_ATTR_WEAK uint32_t tud_audio_n_get_fm_n_cycles_cb(uint8_t rhport, uint8_t ep_ // f_m : Main clock frequency in Hz i.e. master clock to which sample clock is locked // f_s : Current sample rate in Hz -bool tud_audio_set_feedback_params_fm_fs(uint8_t func_id, uint32_t f_m, uint32_t f_s, uint32_t * p_cycle_count, bool use_float); +// p_cycle_count : Pointer to main clock cycle counter register where the current count can be read from (e.g. a timer register) + +// This function must be called from the user within the tud_audio_set_itf_cb(rhport, p_request) callback function, where p_request needs to be checked as +// uint8_t const itf = tu_u16_low(p_request->wIndex); +// uint8_t const alt = tu_u16_low(p_request->wValue); +// such that tud_audio_set_fb_params() gets called with the parameters corresponding to the defined interface and alternate setting +// Also, start the main clock cycle counter (or reset its value) within tud_audio_set_itf_cb() +TU_ATTR_WEAK bool tud_audio_set_fb_params(uint8_t func_id, uint32_t f_m, uint32_t f_s, uint32_t * p_cycle_count); #endif #endif