Implement tud_audio_set_ep_in_target_fifo_size function to set the target fifo size of the ep in flow control

2 files changed, 31 insertions, 5 deletions

diff --git a/src/class/audio/audio_device.c b/src/class/audio/audio_device.c
index 7df177773..7b78b39b8 100644
--- a/src/class/audio/audio_device.c
+++ b/src/class/audio/audio_device.c
@@ -223,6 +223,7 @@ typedef struct
   uint16_t ep_in_sz;        // Current size of TX EP
   uint8_t ep_in_as_intf_num;// Corresponding Standard AS Interface Descriptor (4.9.1) belonging to output terminal to which this EP belongs - 0 is invalid (this fits to UAC2 specification since AS interfaces can not have interface number equal to zero)
   uint8_t ep_in_alt;        // Current alternate setting of TX EP
+  uint16_t ep_in_target_fifo_size;// Target size for the EP IN FIFO.
   #endif
 
 #if CFG_TUD_AUDIO_ENABLE_EP_OUT
@@ -469,7 +470,7 @@ static uint8_t audiod_get_audio_fct_idx(audiod_function_t *audio);
 #if CFG_TUD_AUDIO_ENABLE_EP_IN && CFG_TUD_AUDIO_EP_IN_FLOW_CONTROL
 static void audiod_parse_flow_control_params(audiod_function_t *audio, uint8_t const *p_desc);
 static bool audiod_calc_tx_packet_sz(audiod_function_t *audio);
-static uint16_t audiod_tx_packet_size(const uint16_t *norminal_size, uint16_t data_count, uint16_t fifo_depth, uint16_t max_size);
+static uint16_t audiod_tx_packet_size(const uint16_t *norminal_size, uint16_t data_count, uint16_t fifo_depth, uint16_t target_fifo_size, uint16_t max_size);
 #endif
 
 #if CFG_TUD_AUDIO_ENABLE_EP_OUT && CFG_TUD_AUDIO_ENABLE_FEEDBACK_EP
@@ -563,6 +564,17 @@ tu_fifo_t *tud_audio_n_get_ep_in_ff(uint8_t func_id) {
   return NULL;
 }
 
+uint16_t tud_audio_n_get_ep_in_target_fifo_size(uint8_t func_id) {
+  if (func_id < CFG_TUD_AUDIO) return _audiod_fct[func_id].ep_in_target_fifo_size;
+  return 0;
+}
+
+void tud_audio_n_set_ep_in_target_fifo_size(uint8_t func_id, uint16_t target_fifo_size) {
+  if (func_id < CFG_TUD_AUDIO && target_fifo_size < _audiod_fct[func_id].ep_in_ff.depth) {
+    _audiod_fct[func_id].ep_in_target_fifo_size = target_fifo_size;
+  }
+}
+
 static bool audiod_tx_xfer_isr(uint8_t rhport, audiod_function_t * audio, uint16_t n_bytes_sent) {
   uint8_t idx_audio_fct = audiod_get_audio_fct_idx(audio);
 
@@ -574,7 +586,7 @@ static bool audiod_tx_xfer_isr(uint8_t rhport, audiod_function_t * audio, uint16
 
   #if CFG_TUD_AUDIO_EP_IN_FLOW_CONTROL
   // packet_sz_tx is based on total packet size, here we want size for each support buffer.
-  n_bytes_tx = audiod_tx_packet_size(audio->packet_sz_tx, tu_fifo_count(&audio->ep_in_ff), audio->ep_in_ff.depth, audio->ep_in_sz);
+  n_bytes_tx = audiod_tx_packet_size(audio->packet_sz_tx, tu_fifo_count(&audio->ep_in_ff), audio->ep_in_ff.depth, audio->ep_in_target_fifo_size, audio->ep_in_sz);
   #else
   n_bytes_tx = tu_min16(tu_fifo_count(&audio->ep_in_ff), audio->ep_in_sz);// Limit up to max packet size, more can not be done for ISO
   #endif
@@ -1126,6 +1138,8 @@ static bool audiod_set_interface(uint8_t rhport, tusb_control_request_t const *p
             audio->ep_in_as_intf_num = itf;
             audio->ep_in_alt = alt;
             audio->ep_in_sz = tu_edpt_packet_size(desc_ep);
+            // Set the default EP IN target size to half the fifo depth.
+            audio->ep_in_target_fifo_size = audio->ep_in_ff.depth / 2;
 
             // If flow control is enabled, parse for the corresponding parameters - doing this here means only AS interfaces with EPs get scanned for parameters
   #if  CFG_TUD_AUDIO_EP_IN_FLOW_CONTROL
@@ -1786,7 +1800,7 @@ static bool audiod_calc_tx_packet_sz(audiod_function_t *audio) {
   return true;
 }
 
-static uint16_t audiod_tx_packet_size(const uint16_t *norminal_size, uint16_t data_count, uint16_t fifo_depth, uint16_t max_depth) {
+static uint16_t audiod_tx_packet_size(const uint16_t *norminal_size, uint16_t data_count, uint16_t fifo_depth, uint16_t target_fifo_size, uint16_t max_depth) {
   // Flow control need a FIFO size of at least 4*Navg
   if (norminal_size[1] && norminal_size[1] <= fifo_depth * 4) {
     // Use blackout to prioritize normal size packet
@@ -1796,10 +1810,10 @@ static uint16_t audiod_tx_packet_size(const uint16_t *norminal_size, uint16_t da
     if (data_count < norminal_size[0]) {
       // If you get here frequently, then your I2S clock deviation is too big !
       packet_size = 0;
-    } else if (data_count < fifo_depth / 2 - slot_size && !ctrl_blackout) {
+    } else if (data_count < (target_fifo_size - slot_size) - slot_size && !ctrl_blackout) {
       packet_size = norminal_size[0];
       ctrl_blackout = 10;
-    } else if (data_count > fifo_depth / 2 + slot_size && !ctrl_blackout) {
+    } else if (data_count > (target_fifo_size - slot_size) + slot_size && !ctrl_blackout) {
       packet_size = norminal_size[2];
       if (norminal_size[0] == norminal_size[1]) {
         // nav > INT(nav), eg. 44.1k, 88.2k
diff --git a/src/class/audio/audio_device.h b/src/class/audio/audio_device.h
index b22a918f4..a501c5a19 100644
--- a/src/class/audio/audio_device.h
+++ b/src/class/audio/audio_device.h
@@ -217,6 +217,8 @@ tu_fifo_t* tud_audio_n_get_ep_out_ff   (uint8_t func_id);
 uint16_t   tud_audio_n_write          (uint8_t func_id, const void * data, uint16_t len);
 bool       tud_audio_n_clear_ep_in_ff (uint8_t func_id);
 tu_fifo_t* tud_audio_n_get_ep_in_ff   (uint8_t func_id);
+uint16_t   tud_audio_n_get_ep_in_target_fifo_size(uint8_t func_id);
+void       tud_audio_n_set_ep_in_target_fifo_size(uint8_t func_id, uint16_t target_fifo_size);
 #endif
 
 #if CFG_TUD_AUDIO_ENABLE_INTERRUPT_EP
@@ -432,6 +434,16 @@ TU_ATTR_ALWAYS_INLINE static inline tu_fifo_t* tud_audio_get_ep_in_ff(void) {
   return tud_audio_n_get_ep_in_ff(0);
 }
 
+TU_ATTR_ALWAYS_INLINE static inline uint16_t tud_audio_get_ep_in_target_fifo_size(void)
+{
+  return tud_audio_n_get_ep_in_target_fifo_size(0);
+}
+
+TU_ATTR_ALWAYS_INLINE static inline void tud_audio_set_ep_in_target_fifo_size(uint16_t target_fifo_size)
+{
+  tud_audio_n_set_ep_in_target_fifo_size(0, target_fifo_size);
+}
+
 #endif
 
 #if CFG_TUD_AUDIO_ENABLE_INTERRUPT_EP