Revert "Merge pull request #359 from versioduo/midi-flow-control"

This reverts commit 1d33aa9b6f7940f9eac07ce684515856940175da, reversing
changes made to 718db7e5369df57b0f49a563737e6e0446fd4c4d.

src/class/midi/midi_device.c

@@ -85,19 +85,6 @@ bool tud_midi_n_mounted (uint8_t itf)
   return midi->ep_in && midi->ep_out;
 }
 
-static void _prep_out_transaction (midid_interface_t* p_midi)
-{
-  // skip if previous transfer not complete
-  if ( usbd_edpt_busy(TUD_OPT_RHPORT, p_midi->ep_out) ) return;
-
-  // Prepare for incoming data but only allow what we can store in the ring buffer.
-  uint16_t max_read = tu_fifo_remaining(&p_midi->rx_ff);
-  if ( max_read >= CFG_TUD_MIDI_EPSIZE )
-  {
-    usbd_edpt_xfer(TUD_OPT_RHPORT, p_midi->ep_out, p_midi->epout_buf, CFG_TUD_MIDI_EPSIZE);
-  }
-}
-
 //--------------------------------------------------------------------+
 // READ API
 //--------------------------------------------------------------------+
@@ -151,17 +138,11 @@ void tud_midi_n_read_flush (uint8_t itf, uint8_t jack_id)
 {
   (void) jack_id;
   tu_fifo_clear(&_midid_itf[itf].rx_ff);
-
-  if (tud_ready() && &_midid_itf[itf].ep_out != 0)
-    _prep_out_transaction(&_midid_itf[itf]);
 }
 
 bool tud_midi_n_receive (uint8_t itf, uint8_t packet[4])
 {
-  if (tud_ready() && &_midid_itf[itf].ep_out != 0)
-    _prep_out_transaction(&_midid_itf[itf]);
-
-  return tu_fifo_read_n(&_midid_itf[itf].rx_ff, packet, 4) == 4;
+  return tu_fifo_read_n(&_midid_itf[itf].rx_ff, packet, 4);
 }
 
 void midi_rx_done_cb(midid_interface_t* midi, uint8_t const* buffer, uint32_t bufsize) {
@@ -286,8 +267,8 @@ void midid_init(void)
     midid_interface_t* midi = &_midid_itf[i];
 
     // config fifo
-    tu_fifo_config(&midi->rx_ff, midi->rx_ff_buf, CFG_TUD_MIDI_RX_BUFSIZE, 1, false);
-    tu_fifo_config(&midi->tx_ff, midi->tx_ff_buf, CFG_TUD_MIDI_TX_BUFSIZE, 1, false);
+    tu_fifo_config(&midi->rx_ff, midi->rx_ff_buf, CFG_TUD_MIDI_RX_BUFSIZE, 1, true);
+    tu_fifo_config(&midi->tx_ff, midi->tx_ff_buf, CFG_TUD_MIDI_TX_BUFSIZE, 1, true);
 
     #if CFG_FIFO_MUTEX
     tu_fifo_config_mutex(&midi->rx_ff, osal_mutex_create(&midi->rx_ff_mutex));
@@ -377,7 +358,7 @@ bool midid_open(uint8_t rhport, tusb_desc_interface_t const * desc_itf, uint16_t
   *p_length = drv_len;
 
   // Prepare for incoming data
-  _prep_out_transaction(p_midi);
+  TU_ASSERT( usbd_edpt_xfer(rhport, p_midi->ep_out, p_midi->epout_buf, CFG_TUD_MIDI_EPSIZE), false);
 
   return true;
 }
@@ -400,7 +381,6 @@ bool midid_control_request(uint8_t rhport, tusb_control_request_t const * p_requ
 
 bool midid_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes)
 {
-  (void) rhport;
   (void) result;
 
   uint8_t itf = 0;
@@ -419,8 +399,7 @@ bool midid_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32
     midi_rx_done_cb(p_midi, p_midi->epout_buf, xferred_bytes);
 
     // prepare for next
-    _prep_out_transaction(p_midi);
-
+    TU_ASSERT( usbd_edpt_xfer(rhport, p_midi->ep_out, p_midi->epout_buf, CFG_TUD_MIDI_EPSIZE), false );
   } else if ( ep_addr == p_midi->ep_in ) {
     maybe_transmit(p_midi, itf);
   }