src/class/cdc/cdc_device.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_DEVICE_ENABLED && CFG_TUD_CDC)

#include "cdc_device.h"
#include "device/usbd_pvt.h"

//--------------------------------------------------------------------+
// MACRO CONSTANT TYPEDEF
//--------------------------------------------------------------------+
typedef struct
{
  uint8_t itf_num;
  uint8_t ep_notif;
  uint8_t ep_in;
  uint8_t ep_out;

  // Bit 0:  DTR (Data Terminal Ready), Bit 1: RTS (Request to Send)
  uint8_t line_state;

  /*------------- From this point, data is not cleared by bus reset -------------*/
  char    wanted_char;
  cdc_line_coding_t line_coding;

  // FIFO
  tu_fifo_t rx_ff;
  tu_fifo_t tx_ff;

  uint8_t rx_ff_buf[CFG_TUD_CDC_RX_BUFSIZE];
  uint8_t tx_ff_buf[CFG_TUD_CDC_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_TUD_CDC_EPSIZE];
  CFG_TUSB_MEM_ALIGN uint8_t epin_buf[CFG_TUD_CDC_EPSIZE];

}cdcd_interface_t;

#define ITF_MEM_RESET_SIZE   offsetof(cdcd_interface_t, wanted_char)

//--------------------------------------------------------------------+
// INTERNAL OBJECT & FUNCTION DECLARATION
//--------------------------------------------------------------------+
CFG_TUSB_MEM_SECTION static cdcd_interface_t _cdcd_itf[CFG_TUD_CDC];

static void _prep_out_transaction (uint8_t itf)
{
  cdcd_interface_t* p_cdc = &_cdcd_itf[itf];

  // skip if previous transfer not complete
  if ( usbd_edpt_busy(TUD_OPT_RHPORT, p_cdc->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_cdc->rx_ff);
  if ( max_read >= CFG_TUD_CDC_EPSIZE )
  {
    usbd_edpt_xfer(TUD_OPT_RHPORT, p_cdc->ep_out, p_cdc->epout_buf, CFG_TUD_CDC_EPSIZE);
  }
}

//--------------------------------------------------------------------+
// APPLICATION API
//--------------------------------------------------------------------+
bool tud_cdc_n_connected(uint8_t itf)
{
  // DTR (bit 0) active  is considered as connected
  return tud_ready() && tu_bit_test(_cdcd_itf[itf].line_state, 0);
}

uint8_t tud_cdc_n_get_line_state (uint8_t itf)
{
  return _cdcd_itf[itf].line_state;
}

void tud_cdc_n_get_line_coding (uint8_t itf, cdc_line_coding_t* coding)
{
  (*coding) = _cdcd_itf[itf].line_coding;
}

void tud_cdc_n_set_wanted_char (uint8_t itf, char wanted)
{
  _cdcd_itf[itf].wanted_char = wanted;
}


//--------------------------------------------------------------------+
// READ API
//--------------------------------------------------------------------+
uint32_t tud_cdc_n_available(uint8_t itf)
{
  return tu_fifo_count(&_cdcd_itf[itf].rx_ff);
}

signed char tud_cdc_n_read_char(uint8_t itf)
{
  signed char ch;
  return tud_cdc_n_read(itf, &ch, 1) ? ch : (-1);
}

uint32_t tud_cdc_n_read(uint8_t itf, void* buffer, uint32_t bufsize)
{
  uint32_t num_read = tu_fifo_read_n(&_cdcd_itf[itf].rx_ff, buffer, bufsize);
  _prep_out_transaction(itf);
  return num_read;
}

signed char tud_cdc_n_peek(uint8_t itf, int pos)
{
  signed char ch;
  return tu_fifo_peek_at(&_cdcd_itf[itf].rx_ff, pos, &ch) ? ch : (-1);
}

void tud_cdc_n_read_flush (uint8_t itf)
{
  tu_fifo_clear(&_cdcd_itf[itf].rx_ff);
  _prep_out_transaction(itf);
}

//--------------------------------------------------------------------+
// WRITE API
//--------------------------------------------------------------------+

uint32_t tud_cdc_n_write_char(uint8_t itf, char ch)
{
  return tud_cdc_n_write(itf, &ch, 1);
}

uint32_t tud_cdc_n_write_str (uint8_t itf, char const* str)
{
  return tud_cdc_n_write(itf, str, strlen(str));
}

uint32_t tud_cdc_n_write(uint8_t itf, void const* buffer, uint32_t bufsize)
{
  uint16_t ret = tu_fifo_write_n(&_cdcd_itf[itf].tx_ff, buffer, bufsize);

#if 0 // TODO issue with circuitpython's REPL
  // flush if queue more than endpoint size
  if ( tu_fifo_count(&_cdcd_itf[itf].tx_ff) >= CFG_TUD_CDC_EPSIZE )
  {
    tud_cdc_n_write_flush(itf);
  }
#endif

  return ret;
}

bool tud_cdc_n_write_flush (uint8_t itf)
{
  cdcd_interface_t* p_cdc = &_cdcd_itf[itf];
  TU_VERIFY( !usbd_edpt_busy(TUD_OPT_RHPORT, p_cdc->ep_in) ); // skip if previous transfer not complete

  uint16_t count = tu_fifo_read_n(&_cdcd_itf[itf].tx_ff, p_cdc->epin_buf, CFG_TUD_CDC_EPSIZE);
  if ( count )
  {
    TU_VERIFY( tud_cdc_n_connected(itf) ); // fifo is empty if not connected
    TU_ASSERT( usbd_edpt_xfer(TUD_OPT_RHPORT, p_cdc->ep_in, p_cdc->epin_buf, count) );
  }

  return true;
}


//--------------------------------------------------------------------+
// USBD Driver API
//--------------------------------------------------------------------+
void cdcd_init(void)
{
  tu_memclr(_cdcd_itf, sizeof(_cdcd_itf));

  for(uint8_t i=0; i<CFG_TUD_CDC; i++)
  {
    cdcd_interface_t* p_cdc = &_cdcd_itf[i];

    p_cdc->wanted_char = -1;

    // default line coding is : stop bit = 1, parity = none, data bits = 8
    p_cdc->line_coding.bit_rate = 115200;
    p_cdc->line_coding.stop_bits = 0;
    p_cdc->line_coding.parity    = 0;
    p_cdc->line_coding.data_bits = 8;

    // config fifo
    tu_fifo_config(&p_cdc->rx_ff, p_cdc->rx_ff_buf, CFG_TUD_CDC_RX_BUFSIZE, 1, false);
    tu_fifo_config(&p_cdc->tx_ff, p_cdc->tx_ff_buf, CFG_TUD_CDC_TX_BUFSIZE, 1, false);

#if CFG_FIFO_MUTEX
    tu_fifo_config_mutex(&p_cdc->rx_ff, osal_mutex_create(&p_cdc->rx_ff_mutex));
    tu_fifo_config_mutex(&p_cdc->tx_ff, osal_mutex_create(&p_cdc->tx_ff_mutex));
#endif
  }
}

void cdcd_reset(uint8_t rhport)
{
  (void) rhport;

  for(uint8_t i=0; i<CFG_TUD_CDC; i++)
  {
    tu_memclr(&_cdcd_itf[i], ITF_MEM_RESET_SIZE);
    tu_fifo_clear(&_cdcd_itf[i].rx_ff);
    tu_fifo_clear(&_cdcd_itf[i].tx_ff);
  }
}

bool cdcd_open(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t *p_length)
{
  // Only support ACM subclass
  TU_ASSERT ( CDC_COMM_SUBCLASS_ABSTRACT_CONTROL_MODEL == itf_desc->bInterfaceSubClass);

  // Only support AT commands, no protocol and vendor specific commands.
  TU_ASSERT(tu_within(CDC_COMM_PROTOCOL_NONE, itf_desc->bInterfaceProtocol, CDC_COMM_PROTOCOL_ATCOMMAND_CDMA) ||
            itf_desc->bInterfaceProtocol == 0xff);

  // Find available interface
  cdcd_interface_t * p_cdc = NULL;
  uint8_t cdc_id;
  for(cdc_id=0; cdc_id<CFG_TUD_CDC; cdc_id++)
  {
    if ( _cdcd_itf[cdc_id].ep_in == 0 )
    {
      p_cdc = &_cdcd_itf[cdc_id];
      break;
    }
  }
  TU_ASSERT(p_cdc);

  //------------- Control Interface -------------//
  p_cdc->itf_num = itf_desc->bInterfaceNumber;

  uint8_t const * p_desc = tu_desc_next( itf_desc );
  (*p_length) = sizeof(tusb_desc_interface_t);

  // Communication Functional Descriptors
  while ( TUSB_DESC_CS_INTERFACE == tu_desc_type(p_desc) )
  {
    (*p_length) += tu_desc_len(p_desc);
    p_desc = tu_desc_next(p_desc);
  }

  if ( TUSB_DESC_ENDPOINT == tu_desc_type(p_desc) )
  {
    // notification endpoint if any
    TU_ASSERT( dcd_edpt_open(rhport, (tusb_desc_endpoint_t const *) p_desc) );

    p_cdc->ep_notif = ((tusb_desc_endpoint_t const *) p_desc)->bEndpointAddress;

    (*p_length) += p_desc[DESC_OFFSET_LEN];
    p_desc = tu_desc_next(p_desc);
  }

  //------------- Data Interface (if any) -------------//
  if ( (TUSB_DESC_INTERFACE == p_desc[DESC_OFFSET_TYPE]) &&
       (TUSB_CLASS_CDC_DATA == ((tusb_desc_interface_t const *) p_desc)->bInterfaceClass) )
  {
    // next to endpoint descriptor
    p_desc = tu_desc_next(p_desc);

    // Open endpoint pair
    TU_ASSERT( usbd_open_edpt_pair(rhport, p_desc, 2, TUSB_XFER_BULK, &p_cdc->ep_out, &p_cdc->ep_in) );

    (*p_length) += sizeof(tusb_desc_interface_t) + 2*sizeof(tusb_desc_endpoint_t);
  }

  // Prepare for incoming data
  _prep_out_transaction(cdc_id);

  return true;
}

// Invoked when class request DATA stage is finished.
// return false to stall control endpoint (e.g Host send non-sense DATA)
bool cdcd_control_request_complete(uint8_t rhport, tusb_control_request_t const * request)
{
  (void) rhport;

  //------------- Class Specific Request -------------//
  TU_VERIFY (request->bmRequestType_bit.type == TUSB_REQ_TYPE_CLASS);

  // TODO Support multiple interfaces
  uint8_t const itf = 0;
  cdcd_interface_t* p_cdc = &_cdcd_itf[itf];

  // Invoke callback
  if ( CDC_REQUEST_SET_LINE_CODING == request->bRequest )
  {
    if ( tud_cdc_line_coding_cb ) tud_cdc_line_coding_cb(itf, &p_cdc->line_coding);
  }

  return true;
}

// Handle class control request
// return false to stall control endpoint (e.g unsupported request)
bool cdcd_control_request(uint8_t rhport, tusb_control_request_t const * request)
{
  //------------- Class Specific Request -------------//
  TU_ASSERT(request->bmRequestType_bit.type == TUSB_REQ_TYPE_CLASS);

  // TODO Support multiple interfaces
  uint8_t const itf = 0;
  cdcd_interface_t* p_cdc = &_cdcd_itf[itf];

  switch ( request->bRequest )
  {
    case CDC_REQUEST_SET_LINE_CODING:
      usbd_control_xfer(rhport, request, &p_cdc->line_coding, sizeof(cdc_line_coding_t));
    break;

    case CDC_REQUEST_GET_LINE_CODING:
      usbd_control_xfer(rhport, request, &p_cdc->line_coding, sizeof(cdc_line_coding_t));
    break;

    case CDC_REQUEST_SET_CONTROL_LINE_STATE:
      // CDC PSTN v1.2 section 6.3.12
      // Bit 0: Indicates if DTE is present or not.
      //        This signal corresponds to V.24 signal 108/2 and RS-232 signal DTR (Data Terminal Ready)
      // Bit 1: Carrier control for half-duplex modems.
      //        This signal corresponds to V.24 signal 105 and RS-232 signal RTS (Request to Send)
      p_cdc->line_state = (uint8_t) request->wValue;

      usbd_control_status(rhport, request);

      // Invoke callback
      if ( tud_cdc_line_state_cb) tud_cdc_line_state_cb(itf, tu_bit_test(request->wValue, 0), tu_bit_test(request->wValue, 1));
    break;

    default: return false; // stall unsupported request
  }

  return true;
}

bool cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes)
{
  (void) rhport;
  (void) result;

  // TODO Support multiple interfaces
  uint8_t const itf = 0;
  cdcd_interface_t* p_cdc = &_cdcd_itf[itf];

  // Received new data
  if ( ep_addr == p_cdc->ep_out )
  {
    for(uint32_t i=0; i<xferred_bytes; i++)
    {
      tu_fifo_write(&p_cdc->rx_ff, &p_cdc->epout_buf[i]);

      // Check for wanted char and invoke callback if needed
      if ( tud_cdc_rx_wanted_cb && ( ((signed char) p_cdc->wanted_char) != -1 ) && ( p_cdc->wanted_char == p_cdc->epout_buf[i] ) )
      {
        tud_cdc_rx_wanted_cb(itf, p_cdc->wanted_char);
      }
    }

    // invoke receive callback (if there is still data)
    if (tud_cdc_rx_cb && tu_fifo_count(&p_cdc->rx_ff) ) tud_cdc_rx_cb(itf);

    // prepare for OUT transaction
    _prep_out_transaction(itf);
  }

  // Data sent to host, we could continue to fetch data tx fifo to send.
  // But it will cause incorrect baudrate set in line coding.
  // Though maybe the baudrate is not really important !!!
//  if ( ep_addr == p_cdc->ep_in )
//  {
//
//  }

  // nothing to do with notif endpoint for now

  return true;
}

#endif