Files
lib_xua/examples/xua_lite_example/src/xua_buffer_lite.xc
2018-11-14 10:04:39 +00:00

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#include <stdint.h>
#include <xs1.h>
#include "xua_commands.h"
#include "xud.h"
#include "testct_byref.h"
#define DEBUG_UNIT XUA_LITE_BUFFER
#define DEBUG_PRINT_ENABLE_XUA_LITE_BUFFER 1
#include "debug_print.h"
#include "xua.h"
#include "fifo_impl.h"
#include "xua_ep0_wrapper.h"
//Currently only single frequency supported
#define NOMINAL_SR_DEVICE DEFAULT_FREQ
#define NOMINAL_SR_HOST DEFAULT_FREQ
#define DIV_ROUND_UP(n, d) (n / d + 1) //Always rounds up to the next integer. Needed for 48001Hz case etc.
#define BIGGEST(a, b) (a > b ? a : b)
#define SOF_FREQ_HZ (8000 - ((2 - AUDIO_CLASS) * 7000) )
//Defines for endpoint buffer sizes. Samples is total number of samples across all channels
#define MAX_OUT_SAMPLES_PER_SOF_PERIOD (DIV_ROUND_UP(MAX_FREQ, SOF_FREQ_HZ) * NUM_USB_CHAN_OUT)
#define MAX_IN_SAMPLES_PER_SOF_PERIOD (DIV_ROUND_UP(MAX_FREQ, SOF_FREQ_HZ) * NUM_USB_CHAN_IN)
#define MAX_OUTPUT_SLOT_SIZE 4
#define MAX_INPUT_SLOT_SIZE 4
#define OUT_AUDIO_BUFFER_SIZE_BYTES (MAX_OUT_SAMPLES_PER_SOF_PERIOD * MAX_OUTPUT_SLOT_SIZE)
#define IN_AUDIO_BUFFER_SIZE_BYTES (MAX_IN_SAMPLES_PER_SOF_PERIOD * MAX_INPUT_SLOT_SIZE)
//Helper to disassemble USB packets into 32b left aligned audio samples
#pragma unsafe arrays
static inline void unpack_buff_to_samples(unsigned char input[], const unsigned n_samples, const unsigned slot_size, int output[]){
switch(slot_size){
case 4:
for (int i = 0; i < n_samples; i++){
unsigned base = i * 4;
output[i] = (input[base + 3] << 24) | (input[base + 2] << 16) | (input[base + 1] << 8) | input[base + 0];
}
break;
case 3:
for (int i = 0; i < n_samples; i++){
unsigned base = i * 3;
output[i] = (input[base + 2] << 24) | (input[base + 1] << 16) | (input[base + 0] << 8);
}
break;
case 2:
for (int i = 0; i < n_samples; i++){
unsigned base = i * 2;
output[i] = (input[base + 1] << 24) | (input[base + 0] << 16);
}
break;
default:
debug_printf("Invalid slot_size\n");
break;
}
}
//Helper to assemble USB packets from 32b left aligned audio samples
#pragma unsafe arrays
static inline void pack_samples_to_buff(int input[], const unsigned n_samples, const unsigned slot_size, unsigned char output[]){
switch(slot_size){
case 4:
for (int i = 0; i < n_samples; i++){
unsigned base = i * 4;
unsigned in_word = (unsigned)input[i];
output[base + 0] = in_word & 0xff;
output[base + 1] = (in_word & 0xff00) >> 8;
output[base + 2] = (in_word & 0xff0000) >> 16;
output[base + 3] = (in_word) >> 24;
}
break;
case 3:
for (int i = 0; i < n_samples; i++){
unsigned base = i * 3;
unsigned in_word = (unsigned)input[i];
output[base + 0] = (in_word & 0xff00) >> 8;
output[base + 1] = (in_word & 0xff0000) >> 16;
output[base + 2] = (in_word) >> 24;
}
break;
case 2:
for (int i = 0; i < n_samples; i++){
unsigned base = i * 2;
unsigned in_word = (unsigned)input[i];
output[base + 0] = (in_word & 0xff0000) >> 16;
output[base + 1] = (in_word) >> 24;
}
break;
default:
debug_printf("Invalid slot_size\n");
break;
}
}
static void do_feedback_calculation(unsigned &sof_count
,const unsigned mclk_hz
,unsigned mclk_port_counter
,unsigned &mclk_port_counter_old
,long long &feedback_value
,unsigned &mod_from_last_time
,unsigned fb_clocks[1]){
// Assuming 48kHz from a 24.576 master clock (0.0407uS period)
// MCLK ticks per SOF = 125uS / 0.0407 = 3072 MCLK ticks per SOF.
// expected Feedback is 48000/8000 = 6 samples. so 0x60000 in 16:16 format.
// Average over 128 SOFs - 128 x 3072 = 0x60000.
unsigned long long feedbackMul = 64ULL;
if(AUDIO_CLASS == 1) feedbackMul = 8ULL; // TODO Use 4 instead of 8 to avoid windows LSB issues?
// Number of MCLK ticks in this SOF period (E.g = 125 * 24.576 = 3072)
int mclk_ticks_this_sof_period = (int) ((short)(mclk_port_counter - mclk_port_counter_old));
unsigned long long full_result = mclk_ticks_this_sof_period * feedbackMul * DEFAULT_FREQ;
feedback_value += full_result;
// Store MCLK for next time around...
mclk_port_counter_old = mclk_port_counter;
// Reset counts based on SOF counting. Expect 16ms (128 HS SOFs/16 FS SOFS) per feedback poll
// We always count 128 SOFs, so 16ms @ HS, 128ms @ FS
if(sof_count == 128){
//debug_printf("fb\n");
sof_count = 0;
feedback_value += mod_from_last_time;
unsigned clocks = feedback_value / mclk_hz;
mod_from_last_time = feedback_value % mclk_hz;
feedback_value = 0;
//Scale for working out number of samps to take from device for input
if(AUDIO_CLASS == 2){
clocks <<= 3;
}
else{
clocks <<= 6;
}
asm volatile("stw %0, dp[g_speed]"::"r"(clocks)); // g_speed = clocks
//Write to feedback EP buffer
if (AUDIO_CLASS == 2){
fb_clocks[0] = clocks;
}
else{
fb_clocks[0] = clocks >> 2;
}
}
}
void fill_level_process(int fill_level, int &clock_nudge){
//Because we always check level after USB has produced a block, and total FIFO size is 2x max, half full is at 3/4
const int half_full_out = ((MAX_OUT_SAMPLES_PER_SOF_PERIOD * 2) * 3) / 4;
const int trigger_high_upper = half_full_out + 4;
const int trigger_low_upper = half_full_out - 4;
if (fill_level >= trigger_high_upper){
clock_nudge = 1;
//debug_printf("Nudge down\n");
}
else if (fill_level <= trigger_low_upper){
//debug_printf("Nudge up\n");
clock_nudge = -1;
}
else clock_nudge = 0;
//debug_printf("%d\n", clock_nudge);
static unsigned counter; counter++; if (counter>SOF_FREQ_HZ){counter = 0; debug_printf("f: %d\n",fill_level);}
}
extern "C"{
void XUA_Endpoint0_lite_init(chanend c_ep0_out, chanend c_ep0_in, chanend c_audioControl,
chanend ?c_mix_ctl, chanend ?c_clk_ctl, chanend ?c_EANativeTransport_ctrl, CLIENT_INTERFACE(i_dfu, ?dfuInterface) VENDOR_REQUESTS_PARAMS_DEC_);
void XUA_Endpoint0_lite_loop(XUD_Result_t result, USB_SetupPacket_t sp, chanend c_ep0_out, chanend c_ep0_in, chanend c_audioControl,
chanend ?c_mix_ctl, chanend ?c_clk_ctl, chanend ?c_EANativeTransport_ctrl, CLIENT_INTERFACE(i_dfu, ?dfuInterface) VENDOR_REQUESTS_PARAMS_DEC_, unsigned *input_interface_num, unsigned *output_interface_num);
}
#pragma select handler
void XUD_GetSetupData_Select(chanend c, XUD_ep e_out, unsigned &length, XUD_Result_t &result);
extern XUD_ep ep0_out;
extern XUD_ep ep0_in;
//Unsafe to allow us to use fifo API without local unsafe scope
unsafe void XUA_Buffer_lite(chanend c_ep0_out, chanend c_ep0_in, chanend c_aud_out, chanend ?c_feedback, chanend c_aud_in, chanend c_sof, in port p_for_mclk_count, streaming chanend c_audio_hub) {
debug_printf("%d\n", MAX_OUT_SAMPLES_PER_SOF_PERIOD);
//These buffers are unions so we can access them as different types
union buffer_aud_out{
unsigned char bytes[OUT_AUDIO_BUFFER_SIZE_BYTES];
short short_words[OUT_AUDIO_BUFFER_SIZE_BYTES / 2];
long long_words[OUT_AUDIO_BUFFER_SIZE_BYTES / 4];
}buffer_aud_out;
union buffer_aud_in{
unsigned char bytes[IN_AUDIO_BUFFER_SIZE_BYTES];
short short_words[IN_AUDIO_BUFFER_SIZE_BYTES / 2];
unsigned long long_words[IN_AUDIO_BUFFER_SIZE_BYTES / 4];
}buffer_aud_in;
unsigned in_subslot_size = (AUDIO_CLASS == 1) ? FS_STREAM_FORMAT_INPUT_1_SUBSLOT_BYTES : HS_STREAM_FORMAT_INPUT_1_SUBSLOT_BYTES;
unsigned out_subslot_size = (AUDIO_CLASS == 1) ? FS_STREAM_FORMAT_OUTPUT_1_SUBSLOT_BYTES : HS_STREAM_FORMAT_OUTPUT_1_SUBSLOT_BYTES;
//Asynch feedback calculation
unsigned sof_count = 0;
unsigned mclk_port_counter_old = 0;
long long feedback_value = 0;
unsigned mod_from_last_time = 0;
const unsigned mclk_hz = MCLK_48;
unsigned int fb_clocks[1] = {0};
//Adapative device clock control
int clock_nudge = 0;
//Endpoints
XUD_ep ep_aud_out = XUD_InitEp(c_aud_out);
XUD_ep ep_aud_in = XUD_InitEp(c_aud_in);
XUD_ep ep_feedback = 0;
if (!isnull(c_feedback)) ep_feedback = XUD_InitEp(c_feedback);
unsigned num_samples_received_from_host = 0;
unsigned num_samples_to_send_to_host = 0;
short samples_in_short[NUM_USB_CHAN_IN] = {0};
short samples_out_short[NUM_USB_CHAN_OUT] = {0};
#define c_audioControl null
#define dfuInterface null
XUA_Endpoint0_lite_init(c_ep0_out, c_ep0_in, c_audioControl, null, null, null, dfuInterface);
unsigned char sbuffer[120]; //Raw buffer for EP0 data
USB_SetupPacket_t sp; //Parsed setup packet from EP0
unsigned input_interface_num = 0;
unsigned output_interface_num = 0;
//Enable all EPs
XUD_SetReady_OutPtr(ep_aud_out, (unsigned)buffer_aud_out.long_words);
XUD_SetReady_InPtr(ep_aud_in, (unsigned)buffer_aud_in.long_words, num_samples_to_send_to_host);
XUD_SetReady_Out(ep0_out, sbuffer);
if (!isnull(c_feedback)) XUD_SetReady_InPtr(ep_feedback, (unsigned)fb_clocks, (AUDIO_CLASS == 2) ? 4 : 3);
//Send initial samples so audiohub is not blocked
for (int i = 0; i < 2 * (NUM_USB_CHAN_OUT + (XUA_ADAPTIVE != 0 ? 1 : 0)); i++) c_audio_hub <: 0;
//FIFOs from EP buffers to audio
short host_to_device_fifo_storage[MAX_OUT_SAMPLES_PER_SOF_PERIOD * 2];
short device_to_host_fifo_storage[MAX_IN_SAMPLES_PER_SOF_PERIOD * 2];
mem_fifo_short_t host_to_device_fifo = {sizeof(host_to_device_fifo_storage)/sizeof(host_to_device_fifo_storage[0]), host_to_device_fifo_storage, 0, 0};
mem_fifo_short_t device_to_host_fifo = {sizeof(device_to_host_fifo_storage)/sizeof(device_to_host_fifo_storage[0]), device_to_host_fifo_storage, 0, 0};
volatile mem_fifo_short_t * unsafe host_to_device_fifo_ptr = &host_to_device_fifo;
volatile mem_fifo_short_t * unsafe device_to_host_fifo_ptr = &device_to_host_fifo;
//XUD transaction variables passed in by reference
XUD_Result_t result;
unsigned length = 0;
unsigned u_tmp; //For select channel input by ref on EP0
int s_tmp; //For select on channel from audiohub
while(1){
#pragma ordered
select{
//Handle EP0 requests
case XUD_GetSetupData_Select(c_ep0_out, ep0_out, length, result):
timer tmr; int t0, t1; tmr :> t0;
debug_printf("ep0, result: %d, length: %d\n", result, length); //-1 reset, 0 ok, 1 error
USB_ParseSetupPacket(sbuffer, sp); //Parse data buffer end populate SetupPacket struct
XUA_Endpoint0_lite_loop(result, sp, c_ep0_out, c_ep0_in, c_audioControl, null/*mix*/, null/*clk*/, null/*EA*/, dfuInterface, &input_interface_num, &output_interface_num);
XUD_SetReady_Out(ep0_out, sbuffer);
tmr :> t1; debug_printf("c%d\n", t1 - t0);
break;
//SOF handling
case inuint_byref(c_sof, u_tmp):
timer tmr; int t0, t1; tmr :> t0;
unsigned mclk_port_counter = 0;
asm volatile(" getts %0, res[%1]" : "=r" (mclk_port_counter) : "r" (p_for_mclk_count));
if (!isnull(c_feedback)) do_feedback_calculation(sof_count, mclk_hz, mclk_port_counter, mclk_port_counter_old, feedback_value, mod_from_last_time, fb_clocks);
sof_count++;
tmr :> t1; debug_printf("s%d\n", t1 - t0);
break;
//Receive samples from host
case XUD_GetData_Select(c_aud_out, ep_aud_out, length, result):
timer tmr; int t0, t1; tmr :> t0;
num_samples_received_from_host = length / out_subslot_size;
fifo_ret_t ret = fifo_block_push_short(host_to_device_fifo_ptr, buffer_aud_out.short_words, num_samples_received_from_host);
if (ret != FIFO_SUCCESS) debug_printf("h2d full\n");
num_samples_to_send_to_host = num_samples_received_from_host;
int fill_level = fifo_get_fill_short(host_to_device_fifo_ptr);
fill_level_process(fill_level, clock_nudge);
//Mark EP as ready for next frame from host
XUD_SetReady_OutPtr(ep_aud_out, (unsigned)buffer_aud_out.long_words);
tmr :> t1; debug_printf("o%d\n", t1 - t0);
break;
//Send asynch explicit feedback value, but only if enabled
case !isnull(c_feedback) => XUD_SetData_Select(c_feedback, ep_feedback, result):
timer tmr; int t0, t1; tmr :> t0;
XUD_SetReady_In(ep_feedback, (fb_clocks, unsigned char[]), (AUDIO_CLASS == 2) ? 4 : 3);
//debug_printf("0x%x\n", fb_clocks[0]);
tmr :> t1; debug_printf("f%d\n", t1 - t0);
break;
//Send samples to host
case XUD_SetData_Select(c_aud_in, ep_aud_in, result):
timer tmr; int t0, t1; tmr :> t0;
if (output_interface_num == 0) num_samples_to_send_to_host = (DEFAULT_FREQ / SOF_FREQ_HZ) * NUM_USB_CHAN_IN;
fifo_ret_t ret = fifo_block_pop_short(device_to_host_fifo_ptr, buffer_aud_in.short_words, num_samples_received_from_host);
if (ret != FIFO_SUCCESS) debug_printf("d2h empty\n");
//Populate the input buffer ready for the next read
//pack_samples_to_buff(loopback_samples, num_samples_to_send_to_host, in_subslot_size, buffer_aud_in);
//Use the number of samples we received last time so we are always balanced (assumes same in/out count)
unsigned input_buffer_size = num_samples_to_send_to_host * in_subslot_size;
XUD_SetReady_InPtr(ep_aud_in, (unsigned)buffer_aud_in.long_words, input_buffer_size); //loopback
num_samples_to_send_to_host = 0;
tmr :> t1; debug_printf("i%d\n", t1 - t0);
break;
//Exchange samples with audiohub. Note we are using channel buffering here to act as a FIFO
case c_audio_hub :> s_tmp:
timer tmr; int t0, t1; tmr :> t0;
samples_in_short[0] = s_tmp >> 16;
for (int i = 1; i < NUM_USB_CHAN_IN; i++){
c_audio_hub :> s_tmp;
samples_in_short[i] = s_tmp >> 16;
}
fifo_ret_t ret = fifo_block_pop_short(host_to_device_fifo_ptr, samples_out_short, NUM_USB_CHAN_OUT);
if (ret != FIFO_SUCCESS && output_interface_num != 0) debug_printf("h2d empty\n");
for (int i = 0; i < NUM_USB_CHAN_OUT; i++) c_audio_hub <: (int)samples_out_short[i] << 16;
if (XUA_ADAPTIVE) c_audio_hub <: clock_nudge;
ret = fifo_block_push_short(device_to_host_fifo_ptr, samples_in_short, NUM_USB_CHAN_IN);
if (ret != FIFO_SUCCESS && input_interface_num != 0) debug_printf("d2h full\n");
tmr :> t1; debug_printf("a%d\n", t1 - t0);
break;
}
}
}
extern port p_sda;
[[combinable]]
//Unsafe to allow us to use fifo API without local unsafe scope
unsafe void XUA_Buffer_lite2(server ep0_control_if i_ep0_ctl, chanend c_aud_out, chanend ?c_feedback, chanend c_aud_in, chanend c_sof, in port p_for_mclk_count, streaming chanend c_audio_hub) {
debug_printf("%d\n", MAX_OUT_SAMPLES_PER_SOF_PERIOD);
//These buffers are unions so we can access them as different types
union buffer_aud_out{
unsigned char bytes[OUT_AUDIO_BUFFER_SIZE_BYTES];
short short_words[OUT_AUDIO_BUFFER_SIZE_BYTES / 2];
long long_words[OUT_AUDIO_BUFFER_SIZE_BYTES / 4];
}buffer_aud_out;
union buffer_aud_in{
unsigned char bytes[IN_AUDIO_BUFFER_SIZE_BYTES];
short short_words[IN_AUDIO_BUFFER_SIZE_BYTES / 2];
unsigned long long_words[IN_AUDIO_BUFFER_SIZE_BYTES / 4];
}buffer_aud_in;
unsigned in_subslot_size = (AUDIO_CLASS == 1) ? FS_STREAM_FORMAT_INPUT_1_SUBSLOT_BYTES : HS_STREAM_FORMAT_INPUT_1_SUBSLOT_BYTES;
unsigned out_subslot_size = (AUDIO_CLASS == 1) ? FS_STREAM_FORMAT_OUTPUT_1_SUBSLOT_BYTES : HS_STREAM_FORMAT_OUTPUT_1_SUBSLOT_BYTES;
//Asynch feedback calculation
unsigned sof_count = 0;
unsigned mclk_port_counter_old = 0;
long long feedback_value = 0;
unsigned mod_from_last_time = 0;
const unsigned mclk_hz = MCLK_48;
unsigned int fb_clocks[1] = {0};
//Adapative device clock control
int clock_nudge = 0;
//Endpoints
XUD_ep ep_aud_out = XUD_InitEp(c_aud_out);
XUD_ep ep_aud_in = XUD_InitEp(c_aud_in);
XUD_ep ep_feedback = 0;
if (!isnull(c_feedback)) ep_feedback = XUD_InitEp(c_feedback);
unsigned num_samples_received_from_host = 0;
unsigned num_samples_to_send_to_host = 0;
unsigned input_interface_num = 0;
unsigned output_interface_num = 0;
//Enable all EPs
XUD_SetReady_OutPtr(ep_aud_out, (unsigned)buffer_aud_out.long_words);
XUD_SetReady_InPtr(ep_aud_in, (unsigned)buffer_aud_in.long_words, num_samples_to_send_to_host);
if (!isnull(c_feedback)) XUD_SetReady_InPtr(ep_feedback, (unsigned)fb_clocks, (AUDIO_CLASS == 2) ? 4 : 3);
short samples_in_short[NUM_USB_CHAN_IN] = {0};
short samples_out_short[NUM_USB_CHAN_OUT] = {0};
//Send initial samples so audiohub is not blocked
for (int i = 0; i < 2 * (NUM_USB_CHAN_OUT + (XUA_ADAPTIVE != 0 ? 1 : 0)); i++) c_audio_hub <: 0;
//FIFOs from EP buffers to audio
short host_to_device_fifo_storage[MAX_OUT_SAMPLES_PER_SOF_PERIOD * 2];
short device_to_host_fifo_storage[MAX_IN_SAMPLES_PER_SOF_PERIOD * 2];
mem_fifo_short_t host_to_device_fifo = {sizeof(host_to_device_fifo_storage)/sizeof(host_to_device_fifo_storage[0]), host_to_device_fifo_storage, 0, 0};
mem_fifo_short_t device_to_host_fifo = {sizeof(device_to_host_fifo_storage)/sizeof(device_to_host_fifo_storage[0]), device_to_host_fifo_storage, 0, 0};
volatile mem_fifo_short_t * unsafe host_to_device_fifo_ptr = &host_to_device_fifo;
volatile mem_fifo_short_t * unsafe device_to_host_fifo_ptr = &device_to_host_fifo;
//XUD transaction variables passed in by reference
XUD_Result_t result;
unsigned length = 0;
unsigned u_tmp; //For select channel input by ref on EP0
int s_tmp; //For select on channel from audiohub
while(1){
select{
//Handle EP0 requests
case i_ep0_ctl.set_output_interface(unsigned num):
output_interface_num = num;
debug_printf("output_interface_num: %d\n", num);
break;
case i_ep0_ctl.set_input_interface(unsigned num):
input_interface_num = num;
debug_printf("input_interface_num: %d\n", num);
break;
case i_ep0_ctl.set_host_active(unsigned active):
break;
//SOF handling
case inuint_byref(c_sof, u_tmp):
timer tmr; int t0, t1; tmr :> t0;
unsigned mclk_port_counter = 0;
asm volatile(" getts %0, res[%1]" : "=r" (mclk_port_counter) : "r" (p_for_mclk_count));
if (!isnull(c_feedback)) do_feedback_calculation(sof_count, mclk_hz, mclk_port_counter, mclk_port_counter_old, feedback_value, mod_from_last_time, fb_clocks);
sof_count++;
//tmr :> t1; debug_printf("s%d\n", t1 - t0);
break;
//Receive samples from host
case XUD_GetData_Select(c_aud_out, ep_aud_out, length, result):
timer tmr; int t0, t1; tmr :> t0;
num_samples_received_from_host = length / out_subslot_size;
if (num_samples_received_from_host != 96) debug_printf("hs: %d\n", num_samples_received_from_host);
fifo_ret_t ret = fifo_block_push_short_fast(host_to_device_fifo_ptr, buffer_aud_out.short_words, num_samples_received_from_host);
if (ret != FIFO_SUCCESS) debug_printf("h2d full\n");
num_samples_to_send_to_host = num_samples_received_from_host;
int fill_level = fifo_get_fill_short(host_to_device_fifo_ptr);
fill_level_process(fill_level, clock_nudge);
//Mark EP as ready for next frame from host
XUD_SetReady_OutPtr(ep_aud_out, (unsigned)buffer_aud_out.long_words);
//tmr :> t1; debug_printf("o%d\n", t1 - t0);
break;
//Send asynch explicit feedback value, but only if enabled
case !isnull(c_feedback) => XUD_SetData_Select(c_feedback, ep_feedback, result):
timer tmr; int t0, t1; tmr :> t0;
XUD_SetReady_In(ep_feedback, (fb_clocks, unsigned char[]), (AUDIO_CLASS == 2) ? 4 : 3);
//debug_printf("0x%x\n", fb_clocks[0]);
//tmr :> t1; debug_printf("f%d\n", t1 - t0);
break;
//Send samples to host
case XUD_SetData_Select(c_aud_in, ep_aud_in, result):
timer tmr; int t0, t1; tmr :> t0;
//If host is not streaming out, then send a fixed number of samples to host
if (output_interface_num == 0) num_samples_to_send_to_host = (DEFAULT_FREQ / SOF_FREQ_HZ) * NUM_USB_CHAN_IN;
fifo_ret_t ret = fifo_block_pop_short_fast(device_to_host_fifo_ptr, buffer_aud_in.short_words, num_samples_received_from_host);
if (ret != FIFO_SUCCESS) debug_printf("d2h empty\n");
//Populate the input buffer ready for the next read
//pack_samples_to_buff(loopback_samples, num_samples_to_send_to_host, in_subslot_size, buffer_aud_in);
//Use the number of samples we received last time so we are always balanced (assumes same in/out count)
unsigned input_buffer_size = num_samples_to_send_to_host * in_subslot_size;
XUD_SetReady_InPtr(ep_aud_in, (unsigned)buffer_aud_in.long_words, input_buffer_size); //loopback
num_samples_to_send_to_host = 0;
//tmr :> t1; debug_printf("i%d\n", t1 - t0);
break;
//Exchange samples with audiohub. Note we are using channel buffering here to act as a FIFO
case c_audio_hub :> s_tmp:
timer tmr; int t0, t1; tmr :> t0;
samples_in_short[0] = s_tmp >> 16;
for (int i = 1; i < NUM_USB_CHAN_IN; i++){
c_audio_hub :> s_tmp;
samples_in_short[i] = s_tmp >> 16;
}
fifo_ret_t ret = fifo_block_pop_short(host_to_device_fifo_ptr, samples_out_short, NUM_USB_CHAN_OUT);
if (ret != FIFO_SUCCESS && output_interface_num != 0) debug_printf("h2d empty\n");
for (int i = 0; i < NUM_USB_CHAN_OUT; i++) c_audio_hub <: (int)samples_out_short[i] << 16;
if (XUA_ADAPTIVE) c_audio_hub <: clock_nudge;
ret = fifo_block_push_short(device_to_host_fifo_ptr, samples_in_short, NUM_USB_CHAN_IN);
if (ret != FIFO_SUCCESS && input_interface_num != 0) debug_printf("d2h full\n");
//tmr :> t1; debug_printf("a%d\n", t1 - t0);
break;
}
}
}