tinyUSB/src/class/midi/midi_host.c

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * This file is part of the TinyUSB stack.
 */

#include "tusb_option.h"

#if (TUSB_OPT_HOST_ENABLED && CFG_TUH_MIDI)

#include "host/usbh.h"
#include "host/usbh_pvt.h"

#include "midi_host.h"

//--------------------------------------------------------------------+
// MACRO CONSTANT TYPEDEF
//--------------------------------------------------------------------+

// TODO: refactor to share code with the MIDI Device driver
typedef struct
{
  uint8_t buffer[4];
  uint8_t index;
  uint8_t total;
}midi_stream_t;

typedef struct
{
  uint8_t dev_addr;
  uint8_t itf_num;

  uint8_t ep_in;          // IN endpoint address
  uint8_t ep_out;         // OUT endpoint address
  uint16_t ep_in_max;     // min( CFG_TUH_MIDI_RX_BUFSIZE, wMaxPacketSize of the IN endpoint)
  uint16_t ep_out_max;    //  min( CFG_TUH_MIDI_TX_BUFSIZE, wMaxPacketSize of the OUT endpoint)

  uint8_t num_cables_rx;  // IN endpoint CS descriptor bNumEmbMIDIJack value
  uint8_t num_cables_tx;  // OUT endpoint CS descriptor bNumEmbMIDIJack value

  // For Stream read()/write() API
  // Messages are always 4 bytes long, queue them for reading and writing so the
  // callers can use the Stream interface with single-byte read/write calls.
  midi_stream_t stream_write;
  midi_stream_t stream_read;

  /*------------- From this point, data is not cleared by bus reset -------------*/
  // Endpoint FIFOs
  tu_fifo_t rx_ff;
  tu_fifo_t tx_ff;


  uint8_t rx_ff_buf[CFG_TUH_MIDI_RX_BUFSIZE];
  uint8_t tx_ff_buf[CFG_TUH_MIDI_TX_BUFSIZE];

  #if CFG_FIFO_MUTEX
  osal_mutex_def_t rx_ff_mutex;
  osal_mutex_def_t tx_ff_mutex;
  #endif

  // Endpoint Transfer buffer
  CFG_TUSB_MEM_ALIGN uint8_t epout_buf[CFG_TUH_MIDI_EP_BUFSIZE];
  CFG_TUSB_MEM_ALIGN uint8_t epin_buf[CFG_TUH_MIDI_EP_BUFSIZE];

  bool configured;

#if CFG_MIDI_HOST_DEVSTRINGS
#define MAX_STRING_INDICES 32
  uint8_t all_string_indices[MAX_STRING_INDICES];
  uint8_t num_string_indices;
#define MAX_IN_JACKS 8
#define MAX_OUT_JACKS 8
  struct {
    uint8_t jack_id;
    uint8_t jack_type;
    uint8_t string_index;
  } in_jack_info[MAX_IN_JACKS];
  uint8_t next_in_jack;
  struct {
    uint8_t jack_id;
    uint8_t jack_type;
    uint8_t num_source_ids;
    uint8_t source_ids[MAX_IN_JACKS/4];
    uint8_t string_index;
  } out_jack_info[MAX_OUT_JACKS];
  uint8_t next_out_jack;
  uint8_t ep_in_associated_jacks[MAX_OUT_JACKS/2];
  uint8_t ep_out_associated_jacks[MAX_IN_JACKS/2];
#endif
}midih_interface_t;

static midih_interface_t _midi_host[CFG_TUH_MIDI];

//------------- Internal prototypes -------------//
static uint32_t write_flush(uint8_t dev_addr, midih_interface_t* midi);

//--------------------------------------------------------------------+
// Helper
//--------------------------------------------------------------------+

TU_ATTR_ALWAYS_INLINE static inline midih_interface_t* find_midi_by_daddr(uint8_t dev_addr) {
  for (uint8_t i = 0; i < CFG_TUH_MIDI; i++) {
    if (_midi_host[i].dev_addr == dev_addr) {
      return &_midi_host[i];
    }
  }
  return NULL;
}

TU_ATTR_ALWAYS_INLINE static inline midih_interface_t* find_new_midi(void) {
  return find_midi_by_daddr(0);
}


//--------------------------------------------------------------------+
// USBH API
//--------------------------------------------------------------------+
bool midih_init(void) {
  tu_memclr(&_midi_host, sizeof(_midi_host));
  // config fifos
  for (int inst = 0; inst < CFG_TUH_MIDI; inst++) {
    midih_interface_t *p_midi_host = &_midi_host[inst];
    tu_fifo_config(&p_midi_host->rx_ff, p_midi_host->rx_ff_buf, CFG_TUH_MIDI_RX_BUFSIZE, 1, false);// true, true
    tu_fifo_config(&p_midi_host->tx_ff, p_midi_host->tx_ff_buf, CFG_TUH_MIDI_TX_BUFSIZE, 1, false);// OBVS.

    #if CFG_FIFO_MUTEX
    tu_fifo_config_mutex(&p_midi_host->rx_ff, NULL, osal_mutex_create(&p_midi_host->rx_ff_mutex));
    tu_fifo_config_mutex(&p_midi_host->tx_ff, osal_mutex_create(&p_midi_host->tx_ff_mutex), NULL);
    #endif
  }
  return true;
}

bool midih_xfer_cb(uint8_t dev_addr, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes)
{
  (void)result;
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  if ( ep_addr == p_midi_host->ep_in)
  {
    if (0 == xferred_bytes)
    {
      return true; // No data to handle
    }

    // receive new data if available
    uint32_t packets_queued = 0;
    if (xferred_bytes)
    {
      // put in the RX FIFO only non-zero MIDI IN 4-byte packets
      uint8_t* buf = p_midi_host->epin_buf;
      uint32_t npackets = xferred_bytes / 4;
      uint32_t packet_num;
      for (packet_num = 0; packet_num < npackets; packet_num++)
      {
        // some devices send back all zero packets even if there is no data ready
        uint32_t packet = (uint32_t)((*buf)<<24) | ((uint32_t)(*(buf+1))<<16) | ((uint32_t)(*(buf+2))<<8) | ((uint32_t)(*(buf+3)));
        if (packet != 0)
        {
          tu_fifo_write_n(&p_midi_host->rx_ff, buf, 4);
          ++packets_queued;
          TU_LOG3("MIDI RX=%08x\r\n", packet);
        }
        buf += 4;
      }
    }
    // invoke receive callback if available
    if (tuh_midi_rx_cb)
    {
      tuh_midi_rx_cb(dev_addr, packets_queued);
    }
  }
  else if ( ep_addr == p_midi_host->ep_out )
  {
    if (0 == write_flush(dev_addr, p_midi_host))
    {
      // If there is no data left, a ZLP should be sent if
      // xferred_bytes is multiple of EP size and not zero
      if ( !tu_fifo_count(&p_midi_host->tx_ff) && xferred_bytes && (0 == (xferred_bytes % p_midi_host->ep_out_max)) )
      {
        if ( usbh_edpt_claim(dev_addr, p_midi_host->ep_out) )
        {
          TU_ASSERT(usbh_edpt_xfer(dev_addr, p_midi_host->ep_out, XFER_RESULT_SUCCESS, 0));
        }
      }
    }
    if (tuh_midi_tx_cb)
    {
      tuh_midi_tx_cb(dev_addr);
    }
  }

  return true;
}

void midih_close(uint8_t dev_addr) {
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  if (p_midi_host == NULL) {
    return;
  }
  if (tuh_midi_umount_cb) {
    tuh_midi_umount_cb(dev_addr, 0);
  }
  tu_fifo_clear(&p_midi_host->rx_ff);
  tu_fifo_clear(&p_midi_host->tx_ff);
  p_midi_host->ep_in = 0;
  p_midi_host->ep_in_max = 0;
  p_midi_host->ep_out = 0;
  p_midi_host->ep_out_max = 0;
  p_midi_host->itf_num = 0;
  p_midi_host->num_cables_rx = 0;
  p_midi_host->num_cables_tx = 0;
  p_midi_host->dev_addr = 255; // invalid
  p_midi_host->configured = false;
  tu_memclr(&p_midi_host->stream_read, sizeof(p_midi_host->stream_read));
  tu_memclr(&p_midi_host->stream_write, sizeof(p_midi_host->stream_write));
}

//--------------------------------------------------------------------+
// Enumeration
//--------------------------------------------------------------------+
bool midih_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_interface_t const *desc_itf, uint16_t max_len)
{
  (void) rhport;

  midih_interface_t *p_midi_host = find_new_midi();
  TU_VERIFY(p_midi_host != NULL);

  p_midi_host->num_string_indices = 0;
  TU_VERIFY(TUSB_CLASS_AUDIO == desc_itf->bInterfaceClass);
  // There can be just a MIDI interface or an audio and a MIDI interface. Only open the MIDI interface
  uint8_t const *p_desc = (uint8_t const *) desc_itf;
  uint16_t len_parsed = 0;
  if (AUDIO_SUBCLASS_CONTROL == desc_itf->bInterfaceSubClass) {
    // Keep track of any string descriptor that might be here
    if (desc_itf->iInterface != 0) {
      p_midi_host->all_string_indices[p_midi_host->num_string_indices++] = desc_itf->iInterface;
    }
    // This driver does not support audio streaming. However, if this is the audio control interface
    // there might be a MIDI interface following it. Search through every descriptor until a MIDI
    // interface is found or the end of the descriptor is found
    while (len_parsed < max_len &&
          (desc_itf->bInterfaceClass != TUSB_CLASS_AUDIO || desc_itf->bInterfaceSubClass != AUDIO_SUBCLASS_MIDI_STREAMING)) {
      len_parsed += desc_itf->bLength;
      p_desc = tu_desc_next(p_desc);
      desc_itf = (tusb_desc_interface_t const *)p_desc;
    }

    TU_VERIFY(TUSB_CLASS_AUDIO == desc_itf->bInterfaceClass);
  }
  TU_VERIFY(AUDIO_SUBCLASS_MIDI_STREAMING == desc_itf->bInterfaceSubClass);
  len_parsed += desc_itf->bLength;

  // Keep track of any string descriptor that might be here
  if (desc_itf->iInterface != 0) {
    p_midi_host->all_string_indices[p_midi_host->num_string_indices++] = desc_itf->iInterface;
  }

  p_desc = tu_desc_next(p_desc);
  TU_LOG1("MIDI opening Interface %u (addr = %u)\r\n", desc_itf->bInterfaceNumber, dev_addr);
  // Find out if getting the MIDI class specific interface header or an endpoint descriptor
  // or a class-specific endpoint descriptor
  // Jack descriptors or element descriptors must follow the cs interface header,
  // but this driver does not support devices that contain element descriptors

  // assume it is an interface header
  midi_desc_header_t const *p_mdh = (midi_desc_header_t const *)p_desc;
  TU_VERIFY((p_mdh->bDescriptorType == TUSB_DESC_CS_INTERFACE && p_mdh->bDescriptorSubType == MIDI_CS_INTERFACE_HEADER) ||
            (p_mdh->bDescriptorType == TUSB_DESC_CS_ENDPOINT && p_mdh->bDescriptorSubType == MIDI_CS_ENDPOINT_GENERAL) ||
            p_mdh->bDescriptorType == TUSB_DESC_ENDPOINT);

  uint8_t prev_ep_addr = 0; // the CS endpoint descriptor is associated with the previous endpoint descriptor
  p_midi_host->itf_num = desc_itf->bInterfaceNumber;
  tusb_desc_endpoint_t const* in_desc = NULL;
  tusb_desc_endpoint_t const* out_desc = NULL;
  while (len_parsed < max_len) {
    TU_VERIFY((p_mdh->bDescriptorType == TUSB_DESC_CS_INTERFACE) ||
              (p_mdh->bDescriptorType == TUSB_DESC_CS_ENDPOINT && p_mdh->bDescriptorSubType == MIDI_CS_ENDPOINT_GENERAL) ||
              p_mdh->bDescriptorType == TUSB_DESC_ENDPOINT);

    if (p_mdh->bDescriptorType == TUSB_DESC_CS_INTERFACE) {
      // The USB host doesn't really need this information unless it uses
      // the string descriptor for a jack or Element

      // assume it is an input jack
      midi_desc_in_jack_t const *p_mdij = (midi_desc_in_jack_t const *) p_desc;
      if (p_mdij->bDescriptorSubType == MIDI_CS_INTERFACE_HEADER) {
        TU_LOG2("Found MIDI Interface Header\r\b");
      } else if (p_mdij->bDescriptorSubType == MIDI_CS_INTERFACE_IN_JACK) {
        // Then it is an in jack.
        TU_LOG2("Found in jack\r\n");
  #if CFG_MIDI_HOST_DEVSTRINGS
        if (p_midi_host->next_in_jack < MAX_IN_JACKS) {
          p_midi_host->in_jack_info[p_midi_host->next_in_jack].jack_id = p_mdij->bJackID;
          p_midi_host->in_jack_info[p_midi_host->next_in_jack].jack_type = p_mdij->bJackType;
          p_midi_host->in_jack_info[p_midi_host->next_in_jack].string_index = p_mdij->iJack;
          ++p_midi_host->next_in_jack;
          // Keep track of any string descriptor that might be here
          if (p_mdij->iJack != 0) {
            p_midi_host->all_string_indices[p_midi_host->num_string_indices++] = p_mdij->iJack;
          }
        }
  #endif
      } else if (p_mdij->bDescriptorSubType == MIDI_CS_INTERFACE_OUT_JACK) {
        // then it is an out jack
        TU_LOG2("Found out jack\r\n");
  #if CFG_MIDI_HOST_DEVSTRINGS
        if (p_midi_host->next_out_jack < MAX_OUT_JACKS) {
          midi_desc_out_jack_t const *p_mdoj = (midi_desc_out_jack_t const *) p_desc;
          p_midi_host->out_jack_info[p_midi_host->next_out_jack].jack_id = p_mdoj->bJackID;
          p_midi_host->out_jack_info[p_midi_host->next_out_jack].jack_type = p_mdoj->bJackType;
          p_midi_host->out_jack_info[p_midi_host->next_out_jack].num_source_ids = p_mdoj->bNrInputPins;
          const struct associated_jack_s {
            uint8_t id;
            uint8_t pin;
          } *associated_jack = (const struct associated_jack_s *) (p_desc + 6);
          int jack;
          for (jack = 0; jack < p_mdoj->bNrInputPins; jack++) {
            p_midi_host->out_jack_info[p_midi_host->next_out_jack].source_ids[jack] = associated_jack->id;
          }
          p_midi_host->out_jack_info[p_midi_host->next_out_jack].string_index = *(p_desc + 6 + p_mdoj->bNrInputPins * 2);
          ++p_midi_host->next_out_jack;
          if (p_mdoj->iJack != 0) {
            p_midi_host->all_string_indices[p_midi_host->num_string_indices++] = p_mdoj->iJack;
          }
        }
  #endif
      } else if (p_mdij->bDescriptorSubType == MIDI_CS_INTERFACE_ELEMENT) {
        // the it is an element;
  #if CFG_MIDI_HOST_DEVSTRINGS
        TU_LOG1("Found element; strings not supported\r\n");
  #else
        TU_LOG2("Found element\r\n");
  #endif
      } else {
        TU_LOG2("Unknown CS Interface sub-type %u\r\n", p_mdij->bDescriptorSubType);
        TU_VERIFY(false);// unknown CS Interface sub-type
      }
      len_parsed += p_mdij->bLength;
    } else if (p_mdh->bDescriptorType == TUSB_DESC_CS_ENDPOINT) {
      TU_LOG2("found CS_ENDPOINT Descriptor for %u\r\n", prev_ep_addr);
      TU_VERIFY(prev_ep_addr != 0);
      // parse out the mapping between the device's embedded jacks and the endpoints
      // Each embedded IN jack is associated with an OUT endpoint
      midi_cs_desc_endpoint_t const *p_csep = (midi_cs_desc_endpoint_t const *) p_mdh;
      if (tu_edpt_dir(prev_ep_addr) == TUSB_DIR_OUT) {
        TU_VERIFY(p_midi_host->ep_out == prev_ep_addr);
        TU_VERIFY(p_midi_host->num_cables_tx == 0);
        p_midi_host->num_cables_tx = p_csep->bNumEmbMIDIJack;
  #if CFG_MIDI_HOST_DEVSTRINGS
        uint8_t jack;
        uint8_t max_jack = p_midi_host->num_cables_tx;
        if (max_jack > sizeof(p_midi_host->ep_out_associated_jacks)) {
          max_jack = sizeof(p_midi_host->ep_out_associated_jacks);
        }
        for (jack = 0; jack < max_jack; jack++) {
          p_midi_host->ep_out_associated_jacks[jack] = p_csep->baAssocJackID[jack];
        }
  #endif
      } else {
        TU_VERIFY(p_midi_host->ep_in == prev_ep_addr);
        TU_VERIFY(p_midi_host->num_cables_rx == 0);
        p_midi_host->num_cables_rx = p_csep->bNumEmbMIDIJack;
  #if CFG_MIDI_HOST_DEVSTRINGS
        uint8_t jack;
        uint8_t max_jack = p_midi_host->num_cables_rx;
        if (max_jack > sizeof(p_midi_host->ep_in_associated_jacks)) {
          max_jack = sizeof(p_midi_host->ep_in_associated_jacks);
        }
        for (jack = 0; jack < max_jack; jack++) {
          p_midi_host->ep_in_associated_jacks[jack] = p_csep->baAssocJackID[jack];
        }
  #endif
      }
      len_parsed += p_csep->bLength;
      prev_ep_addr = 0;
    } else if (p_mdh->bDescriptorType == TUSB_DESC_ENDPOINT) {
      // parse out the bulk endpoint info
      tusb_desc_endpoint_t const *p_ep = (tusb_desc_endpoint_t const *) p_mdh;
      TU_LOG2("found ENDPOINT Descriptor for %u\r\n", p_ep->bEndpointAddress);
      if (tu_edpt_dir(p_ep->bEndpointAddress) == TUSB_DIR_OUT) {
        TU_VERIFY(p_midi_host->ep_out == 0);
        TU_VERIFY(p_midi_host->num_cables_tx == 0);
        p_midi_host->ep_out = p_ep->bEndpointAddress;
        p_midi_host->ep_out_max = p_ep->wMaxPacketSize;
        if (p_midi_host->ep_out_max > CFG_TUH_MIDI_TX_BUFSIZE) {
          p_midi_host->ep_out_max = CFG_TUH_MIDI_TX_BUFSIZE;
        }
        prev_ep_addr = p_midi_host->ep_out;
        out_desc = p_ep;
      } else {
        TU_VERIFY(p_midi_host->ep_in == 0);
        TU_VERIFY(p_midi_host->num_cables_rx == 0);
        p_midi_host->ep_in = p_ep->bEndpointAddress;
        p_midi_host->ep_in_max = p_ep->wMaxPacketSize;
        if (p_midi_host->ep_in_max > CFG_TUH_MIDI_RX_BUFSIZE) {
          p_midi_host->ep_in_max = CFG_TUH_MIDI_RX_BUFSIZE;
        }
        prev_ep_addr = p_midi_host->ep_in;
        in_desc = p_ep;
      }
      len_parsed += p_mdh->bLength;
    }
    p_desc = tu_desc_next(p_desc);
    p_mdh = (midi_desc_header_t const *) p_desc;
  }
  TU_VERIFY((p_midi_host->ep_out != 0 && p_midi_host->num_cables_tx != 0) ||
            (p_midi_host->ep_in != 0 && p_midi_host->num_cables_rx != 0));
  TU_LOG1("MIDI descriptor parsed successfully\r\n");
  // remove duplicate string indices
  for (int idx = 0; idx < p_midi_host->num_string_indices; idx++) {
    for (int jdx = idx + 1; jdx < p_midi_host->num_string_indices; jdx++) {
      while (jdx < p_midi_host->num_string_indices && p_midi_host->all_string_indices[idx] == p_midi_host->all_string_indices[jdx]) {
        // delete the duplicate by overwriting it with the last entry and reducing the number of entries by 1
        p_midi_host->all_string_indices[jdx] = p_midi_host->all_string_indices[p_midi_host->num_string_indices - 1];
        --p_midi_host->num_string_indices;
      }
    }
  }
  if (in_desc) {
    TU_ASSERT(tuh_edpt_open(dev_addr, in_desc));
    // Some devices always return exactly the request length so transfers won't complete
    // unless you assume every transfer is the last one.
    // TODO usbh_edpt_force_last_buffer(dev_addr, p_midi_host->ep_in, true);
  }
  if (out_desc) {
    TU_ASSERT(tuh_edpt_open(dev_addr, out_desc));
  }
  p_midi_host->dev_addr = dev_addr;

  if (tuh_midi_mount_cb) {
    tuh_midi_mount_cb(dev_addr, p_midi_host->ep_in, p_midi_host->ep_out, p_midi_host->num_cables_rx, p_midi_host->num_cables_tx);
  }
  return true;
}

bool tuh_midi_configured(uint8_t dev_addr)
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  return p_midi_host->configured;
}

bool midih_set_config(uint8_t dev_addr, uint8_t itf_num)
{
  (void) itf_num;
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  p_midi_host->configured = true;

  // TODO I don't think there are any special config things to do for MIDI
  usbh_driver_set_config_complete(dev_addr, p_midi_host->itf_num);
  return true;
}

//--------------------------------------------------------------------+
// Stream API
//--------------------------------------------------------------------+
static uint32_t write_flush(uint8_t dev_addr, midih_interface_t* midi) {
  // No data to send
  if ( !tu_fifo_count(&midi->tx_ff) ) { return 0; }

  // skip if previous transfer not complete
  TU_VERIFY( usbh_edpt_claim(dev_addr, midi->ep_out) );

  uint16_t count = tu_fifo_read_n(&midi->tx_ff, midi->epout_buf, midi->ep_out_max);

  if (count) {
    TU_ASSERT(usbh_edpt_xfer(dev_addr, midi->ep_out, midi->epout_buf, count), 0);
    return count;
  } else {
    // Release endpoint since we don't make any transfer
    usbh_edpt_release(dev_addr, midi->ep_out);
    return 0;
  }
}

bool tuh_midi_read_poll(uint8_t dev_addr) {
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  bool result = false;

  bool in_edpt_not_busy = !usbh_edpt_busy(dev_addr, p_midi_host->ep_in);
  if (in_edpt_not_busy) {
    TU_LOG2("Requesting poll IN endpoint %d\r\n", p_midi_host->ep_in);
    TU_ASSERT(usbh_edpt_xfer(p_midi_host->dev_addr, p_midi_host->ep_in, p_midi_host->epin_buf, p_midi_host->ep_in_max), 0);
    result = true;
  } else {
    // Maybe the IN endpoint is only busy because the RP2040 host hardware
    // is retrying a NAK'd IN transfer forever. Try aborting the NAK'd
    // transfer to allow other transfers to happen on the one shared
    // epx endpoint.
    // TODO for RP2040 USB shared endpoint: usbh_edpt_clear_in_on_nak(p_midi_host->dev_addr, p_midi_host->ep_in);
  }
  return result;
}

uint32_t tuh_midi_stream_write (uint8_t dev_addr, uint8_t cable_num, uint8_t const* buffer, uint32_t bufsize)
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  TU_VERIFY(cable_num < p_midi_host->num_cables_tx);
  midi_stream_t *stream = &p_midi_host->stream_write;

  uint32_t i = 0;
  while ( (i < bufsize) && (tu_fifo_remaining(&p_midi_host->tx_ff) >= 4) )
  {
    uint8_t const data = buffer[i];
    i++;
    if (data >= MIDI_STATUS_SYSREAL_TIMING_CLOCK)
    {
      // real-time messages need to be sent right away
      midi_stream_t streamrt;
      streamrt.buffer[0] = MIDI_CIN_SYSEX_END_1BYTE;
      streamrt.buffer[1] = data;
      streamrt.index = 2;
      streamrt.total = 2;
      uint16_t const count = tu_fifo_write_n(&p_midi_host->tx_ff, streamrt.buffer, 4);
      // FIFO overflown, since we already check fifo remaining. It is probably race condition
      TU_ASSERT(count == 4, i);
    }
    else if ( stream->index == 0 )
    {
      //------------- New event packet -------------//

      uint8_t const msg = data >> 4;

      stream->index = 2;
      stream->buffer[1] = data;

      // Check to see if we're still in a SysEx transmit.
      if ( stream->buffer[0] == MIDI_CIN_SYSEX_START )
      {
        if ( data == MIDI_STATUS_SYSEX_END )
        {
          stream->buffer[0] = MIDI_CIN_SYSEX_END_1BYTE;
          stream->total = 2;
        }
        else
        {
          stream->total = 4;
        }
      }
      else if ( (msg >= 0x8 && msg <= 0xB) || msg == 0xE )
      {
        // Channel Voice Messages
        stream->buffer[0] = (uint8_t) ((cable_num << 4) | msg);
        stream->total = 4;
      }
      else if ( msg == 0xC || msg == 0xD)
      {
        // Channel Voice Messages, two-byte variants (Program Change and Channel Pressure)
        stream->buffer[0] = (uint8_t) ((cable_num << 4) | msg);
        stream->total = 3;
      }
      else if ( msg == 0xf )
      {
        // System message
        if ( data == MIDI_STATUS_SYSEX_START )
        {
          stream->buffer[0] = MIDI_CIN_SYSEX_START;
          stream->total = 4;
        }
        else if ( data == MIDI_STATUS_SYSCOM_TIME_CODE_QUARTER_FRAME || data == MIDI_STATUS_SYSCOM_SONG_SELECT )
        {
          stream->buffer[0] = MIDI_CIN_SYSCOM_2BYTE;
          stream->total = 3;
        }
        else if ( data == MIDI_STATUS_SYSCOM_SONG_POSITION_POINTER )
        {
          stream->buffer[0] = MIDI_CIN_SYSCOM_3BYTE;
          stream->total = 4;
        }
        else
        {
          stream->buffer[0] = MIDI_CIN_SYSEX_END_1BYTE;
          stream->total = 2;
        }
      }
      else
      {
        // Pack individual bytes if we don't support packing them into words.
        stream->buffer[0] = (uint8_t) (cable_num << 4 | 0xf);
        stream->buffer[2] = 0;
        stream->buffer[3] = 0;
        stream->index = 2;
        stream->total = 2;
      }
    }
    else
    {
      //------------- On-going (buffering) packet -------------//

      TU_ASSERT(stream->index < 4, i);
      stream->buffer[stream->index] = data;
      stream->index++;
      // See if this byte ends a SysEx.
      if ( stream->buffer[0] == MIDI_CIN_SYSEX_START && data == MIDI_STATUS_SYSEX_END )
      {
        stream->buffer[0] = MIDI_CIN_SYSEX_START + (stream->index - 1);
        stream->total = stream->index;
      }
    }

    // Send out packet
    if ( stream->index >= 2 && stream->index == stream->total )
    {
      // zeroes unused bytes
      for(uint8_t idx = stream->total; idx < 4; idx++) stream->buffer[idx] = 0;
      TU_LOG3_MEM(stream->buffer, 4, 2);

      uint16_t const count = tu_fifo_write_n(&p_midi_host->tx_ff, stream->buffer, 4);

      // complete current event packet, reset stream
      stream->index = 0;
      stream->total = 0;

      // FIFO overflown, since we already check fifo remaining. It is probably race condition
      TU_ASSERT(count == 4, i);
    }
  }
  return i;
}

bool tuh_midi_packet_write (uint8_t dev_addr, uint8_t const packet[4])
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);

  if (tu_fifo_remaining(&p_midi_host->tx_ff) < 4)
  {
    return false;
  }

  tu_fifo_write_n(&p_midi_host->tx_ff, packet, 4);

  return true;
}

uint32_t tuh_midi_stream_flush( uint8_t dev_addr )
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);

  uint32_t bytes_flushed = 0;
  if (!usbh_edpt_busy(p_midi_host->dev_addr, p_midi_host->ep_out))
  {
    bytes_flushed = write_flush(dev_addr, p_midi_host);
  }
  return bytes_flushed;
}
//--------------------------------------------------------------------+
// Helper
//--------------------------------------------------------------------+
uint8_t tuh_midih_get_num_tx_cables (uint8_t dev_addr)
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  TU_VERIFY(p_midi_host->ep_out != 0); // returns 0 if fails
  return p_midi_host->num_cables_tx;
}

uint8_t tuh_midih_get_num_rx_cables (uint8_t dev_addr)
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  TU_VERIFY(p_midi_host->ep_in != 0); // returns 0 if fails
  return p_midi_host->num_cables_rx;
}

bool tuh_midi_packet_read (uint8_t dev_addr, uint8_t packet[4])
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  TU_VERIFY(tu_fifo_count(&p_midi_host->rx_ff) >= 4);
  return tu_fifo_read_n(&p_midi_host->rx_ff, packet, 4) == 4;
}

uint32_t tuh_midi_stream_read (uint8_t dev_addr, uint8_t *p_cable_num, uint8_t *p_buffer, uint16_t bufsize)
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  uint32_t bytes_buffered = 0;
  TU_ASSERT(p_cable_num);
  TU_ASSERT(p_buffer);
  TU_ASSERT(bufsize);
  uint8_t one_byte;
  if (!tu_fifo_peek(&p_midi_host->rx_ff, &one_byte))
  {
    return 0;
  }
  *p_cable_num = (one_byte >> 4) & 0xf;
  uint32_t nread = tu_fifo_read_n(&p_midi_host->rx_ff, p_midi_host->stream_read.buffer, 4);
  static uint16_t cable_sysex_in_progress; // bit i is set if received MIDI_STATUS_SYSEX_START but not MIDI_STATUS_SYSEX_END
  while (nread == 4 && bytes_buffered < bufsize)
  {
    *p_cable_num=(p_midi_host->stream_read.buffer[0] >> 4) & 0x0f;
    uint8_t bytes_to_add_to_stream = 0;
    if (*p_cable_num < p_midi_host->num_cables_rx)
    {
      // ignore the CIN field; too many devices out there encode this wrong
      uint8_t status = p_midi_host->stream_read.buffer[1];
      uint16_t cable_mask = (uint16_t) (1 << *p_cable_num);
      if (status <= MIDI_MAX_DATA_VAL || status == MIDI_STATUS_SYSEX_START)
      {
        if (status == MIDI_STATUS_SYSEX_START)
        {
          cable_sysex_in_progress |= cable_mask;
        }
        // only add the packet if a sysex message is in progress
        if (cable_sysex_in_progress & cable_mask)
        {
          ++bytes_to_add_to_stream;
          uint8_t idx;
          for (idx = 2; idx < 4; idx++)
          {
            if (p_midi_host->stream_read.buffer[idx] <= MIDI_MAX_DATA_VAL)
            {
              ++bytes_to_add_to_stream;
            }
            else if (p_midi_host->stream_read.buffer[idx] == MIDI_STATUS_SYSEX_END)
            {
              ++bytes_to_add_to_stream;
              cable_sysex_in_progress &= (uint16_t) ~cable_mask;
              idx = 4; // force the loop to exit; I hate break statements in loops
            }
          }
        }
      }
      else if (status < MIDI_STATUS_SYSEX_START)
      {
        // then it is a channel message either three bytes or two
        uint8_t fake_cin = (status & 0xf0) >> 4;
        switch (fake_cin)
        {
          case MIDI_CIN_NOTE_OFF:
          case MIDI_CIN_NOTE_ON:
          case MIDI_CIN_POLY_KEYPRESS:
          case MIDI_CIN_CONTROL_CHANGE:
          case MIDI_CIN_PITCH_BEND_CHANGE:
            bytes_to_add_to_stream = 3;
            break;
          case MIDI_CIN_PROGRAM_CHANGE:
          case MIDI_CIN_CHANNEL_PRESSURE:
            bytes_to_add_to_stream = 2;
            break;
          default:
            break; // Should not get this
        }
        cable_sysex_in_progress &= (uint16_t)~cable_mask;
      }
      else if (status < MIDI_STATUS_SYSREAL_TIMING_CLOCK)
      {
        switch (status)
        {
          case MIDI_STATUS_SYSCOM_TIME_CODE_QUARTER_FRAME:
          case MIDI_STATUS_SYSCOM_SONG_SELECT:
            bytes_to_add_to_stream = 2;
            break;
          case MIDI_STATUS_SYSCOM_SONG_POSITION_POINTER:
            bytes_to_add_to_stream = 3;
            break;
          case MIDI_STATUS_SYSCOM_TUNE_REQUEST:
          case MIDI_STATUS_SYSEX_END:
            bytes_to_add_to_stream = 1;
            break;
          default:
            break;
          cable_sysex_in_progress &= (uint16_t)~cable_mask;
        }
      }
      else
      {
        // Real-time message: can be inserted into a sysex message,
        // so do don't clear cable_sysex_in_progress bit
        bytes_to_add_to_stream = 1;
      }
    }
    uint8_t idx;
    for (idx = 1; idx <= bytes_to_add_to_stream; idx++)
    {
      *p_buffer++ = p_midi_host->stream_read.buffer[idx];
    }
    bytes_buffered += bytes_to_add_to_stream;
    nread = 0;
    if (tu_fifo_peek(&p_midi_host->rx_ff, &one_byte))
    {
      uint8_t new_cable = (one_byte >> 4) & 0xf;
      if (new_cable == *p_cable_num)
      {
        // still on the same cable. Continue reading the stream
        nread = tu_fifo_read_n(&p_midi_host->rx_ff, p_midi_host->stream_read.buffer, 4);
      }
    }
  }

  return bytes_buffered;
}

uint8_t tuh_midi_get_num_rx_cables(uint8_t dev_addr)
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  uint8_t num_cables = 0;
  if (p_midi_host)
  {
    num_cables = p_midi_host->num_cables_rx;
  }
  return num_cables;
}

uint8_t tuh_midi_get_num_tx_cables(uint8_t dev_addr)
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  uint8_t num_cables = 0;
  if (p_midi_host)
  {
    num_cables = p_midi_host->num_cables_tx;
  }
  return num_cables;
}

#if CFG_MIDI_HOST_DEVSTRINGS
static uint8_t find_string_index(midih_interface_t *ptr, uint8_t jack_id)
{
  uint8_t index = 0;
  uint8_t assoc;
  for (assoc = 0; index == 0 && assoc < ptr->next_in_jack; assoc++)
  {
    if (jack_id == ptr->in_jack_info[assoc].jack_id)
    {
      index = ptr->in_jack_info[assoc].string_index;
    }
  }
  for (assoc = 0; index == 0 && assoc < ptr->next_out_jack; assoc++)
  {
    if (jack_id == ptr->out_jack_info[assoc].jack_id)
    {
      index = ptr->out_jack_info[assoc].string_index;
    }
  }
  return index;
}
#endif

#if CFG_MIDI_HOST_DEVSTRINGS
uint8_t tuh_midi_get_rx_cable_istrings(uint8_t dev_addr, uint8_t* istrings, uint8_t max_istrings)
{
  uint8_t nstrings = 0;
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  nstrings = p_midi_host->num_cables_rx;
  if (nstrings > max_istrings)
  {
      nstrings = max_istrings;
  }
  uint8_t jack;
  for (jack=0; jack<nstrings; jack++)
  {
    uint8_t jack_id = p_midi_host->ep_in_associated_jacks[jack];
    istrings[jack] = find_string_index(p_midi_host, jack_id);
  }
  return nstrings;
}

uint8_t tuh_midi_get_tx_cable_istrings(uint8_t dev_addr, uint8_t* istrings, uint8_t max_istrings)
{
  uint8_t nstrings = 0;
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  nstrings = p_midi_host->num_cables_tx;
  if (nstrings > max_istrings)
  {
      nstrings = max_istrings;
  }
  uint8_t jack;
  for (jack=0; jack<nstrings; jack++)
  {
    uint8_t jack_id = p_midi_host->ep_out_associated_jacks[jack];
    istrings[jack] = find_string_index(p_midi_host, jack_id);
  }
  return nstrings;
}
#endif

uint8_t tuh_midi_get_all_istrings(uint8_t dev_addr, const uint8_t** istrings)
{
  midih_interface_t *p_midi_host = find_midi_by_daddr(dev_addr);
  TU_VERIFY(p_midi_host != NULL);
  uint8_t nstrings = p_midi_host->num_string_indices;
  if (nstrings)
    *istrings = p_midi_host->all_string_indices;
  return nstrings;
}
#endif