source: rtos_arduino/trunk/arduino_lib/hardware/arduino/samd/cores/arduino/USB/CDC.cpp@ 224

/*
  Copyright (c) 2015 Arduino LLC.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
/*
** Modified 04/04/2016 by Arduino.org development team
*/

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>

// Include Atmel headers
#include <Arduino.h>
#include <Reset.h> 

#ifdef CDC_ENABLED

#define CDC_SERIAL_BUFFER_SIZE  256

/* For information purpose only since RTS is not always handled by the terminal application */
#define CDC_LINESTATE_DTR               0x01 // Data Terminal Ready
#define CDC_LINESTATE_RTS               0x02 // Ready to Send

#define CDC_LINESTATE_READY             (CDC_LINESTATE_RTS | CDC_LINESTATE_DTR)

struct ring_buffer {
        uint8_t buffer[CDC_SERIAL_BUFFER_SIZE];
        volatile uint32_t head;
        volatile uint32_t tail;
        volatile bool full;
};
ring_buffer cdc_rx_buffer = {{0}, 0, 0, false};

typedef struct {
        uint32_t dwDTERate;
        uint8_t bCharFormat;
        uint8_t bParityType;
        uint8_t bDataBits;
        uint8_t lineState;
} LineInfo;

_Pragma("pack(1)")
static volatile LineInfo _usbLineInfo = {
        115200, // dWDTERate
        0x00,   // bCharFormat
        0x00,   // bParityType
        0x08,   // bDataBits
        0x00    // lineState
};

static volatile int32_t breakValue = -1;

static CDCDescriptor _cdcInterface = {
        D_IAD(0, 2, CDC_COMMUNICATION_INTERFACE_CLASS, CDC_ABSTRACT_CONTROL_MODEL, 0),

        // CDC communication interface
        D_INTERFACE(CDC_ACM_INTERFACE, 1, CDC_COMMUNICATION_INTERFACE_CLASS, CDC_ABSTRACT_CONTROL_MODEL, 0),
        D_CDCCS(CDC_HEADER, CDC_V1_10 & 0xFF, (CDC_V1_10>>8) & 0x0FF), // Header (1.10 bcd)

        D_CDCCS4(CDC_ABSTRACT_CONTROL_MANAGEMENT, 6), // SET_LINE_CODING, GET_LINE_CODING, SET_CONTROL_LINE_STATE supported
        D_CDCCS(CDC_UNION, CDC_ACM_INTERFACE, CDC_DATA_INTERFACE), // Communication interface is master, data interface is slave 0
        D_CDCCS(CDC_CALL_MANAGEMENT, 1, 1), // Device handles call management (not)
        D_ENDPOINT(USB_ENDPOINT_IN(CDC_ENDPOINT_ACM), USB_ENDPOINT_TYPE_INTERRUPT, 0x10, 0x10),

        // CDC data interface
        D_INTERFACE(CDC_DATA_INTERFACE, 2, CDC_DATA_INTERFACE_CLASS, 0, 0),
        D_ENDPOINT(USB_ENDPOINT_OUT(CDC_ENDPOINT_OUT), USB_ENDPOINT_TYPE_BULK, EPX_SIZE, 0),
        D_ENDPOINT(USB_ENDPOINT_IN (CDC_ENDPOINT_IN ), USB_ENDPOINT_TYPE_BULK, EPX_SIZE, 0)
};
_Pragma("pack()")

const void* _CDC_GetInterface(void)
{
        return &_cdcInterface;
}

uint32_t _CDC_GetInterfaceLength(void)
{
        return sizeof(_cdcInterface);
}

int CDC_GetInterface(uint8_t* interfaceNum)
{
        interfaceNum[0] += 2;   // uses 2
        return USBD_SendControl(&_cdcInterface,sizeof(_cdcInterface));
}

bool CDC_Setup(Setup& pSetup)
{
        uint8_t requestType = pSetup.bmRequestType;
        uint8_t r = pSetup.bRequest;

        if (REQUEST_DEVICETOHOST_CLASS_INTERFACE == requestType)
        {
                if (CDC_GET_LINE_CODING == r)
                {
                        USBD_SendControl((void*)&_usbLineInfo, 7);
                        return true;
                }
        }

        if (REQUEST_HOSTTODEVICE_CLASS_INTERFACE == requestType)
        {
                if (CDC_SET_LINE_CODING == r)
                {
                        USBD_RecvControl((void*)&_usbLineInfo, 7);
                }

                if (CDC_SET_CONTROL_LINE_STATE == r)
                {
                        _usbLineInfo.lineState = pSetup.wValueL;
                }

                if (r == CDC_SET_LINE_CODING || r == CDC_SET_CONTROL_LINE_STATE)
                {
                        // auto-reset into the bootloader is triggered when the port, already
                        // open at 1200 bps, is closed. We check DTR state to determine if host 
                        // port is open (bit 0 of lineState).
                        if (_usbLineInfo.dwDTERate == 1200 && (_usbLineInfo.lineState & 0x01) == 0)
                        {
                                initiateReset(250);
                        }
                        else
                        {
                                cancelReset();
                        }
                        return false;
                }

                if (r == CDC_SEND_BREAK)
                {
                        breakValue = ((uint16_t)pSetup.wValueH << 8) | pSetup.wValueL;
                        return false;
                }
        }
        return false;
}

uint32_t _serialPeek = -1;
void Serial_::begin(uint32_t baud_count)
{
}

void Serial_::begin(uint32_t baud_count, uint8_t config)
{
}

void Serial_::end(void)
{
}

void Serial_::accept(void)
{
        uint8_t buffer[CDC_SERIAL_BUFFER_SIZE];
        uint32_t len = USBD_Recv(CDC_ENDPOINT_OUT, &buffer, CDC_SERIAL_BUFFER_SIZE);

        uint8_t enableInterrupts = ((__get_PRIMASK() & 0x1) == 0);
        __disable_irq();

        ring_buffer *ringBuffer = &cdc_rx_buffer;
        uint32_t i = ringBuffer->head;

        uint32_t k = 0;
        while (len > 0 && !ringBuffer->full) {
                len--;
                ringBuffer->buffer[i++] = buffer[k++];
                i %= CDC_SERIAL_BUFFER_SIZE;
                if (i == ringBuffer->tail)
                        ringBuffer->full = true;
        }
        ringBuffer->head = i;
        if (enableInterrupts) {
                __enable_irq();
        }
}

int Serial_::available(void)
{
        ring_buffer *buffer = &cdc_rx_buffer;
        if (buffer->full) {
                return CDC_SERIAL_BUFFER_SIZE;
        }
        if (buffer->head == buffer->tail) {
                USB->DEVICE.DeviceEndpoint[CDC_ENDPOINT_OUT].EPINTENSET.reg = USB_DEVICE_EPINTENCLR_TRCPT(1);
        }
        return (uint32_t)(CDC_SERIAL_BUFFER_SIZE + buffer->head - buffer->tail) % CDC_SERIAL_BUFFER_SIZE;
}

int Serial_::peek(void)
{
        ring_buffer *buffer = &cdc_rx_buffer;
        if (buffer->head == buffer->tail && !buffer->full) {
                return -1;
        } else {
                return buffer->buffer[buffer->tail];
        }
}


// if the ringBuffer is empty: try to fill it
// if it's still empty: return -1
// else return the last char
// so the buffer is filled only when needed
int Serial_::read(void)
{
        ring_buffer *buffer = &cdc_rx_buffer;

        // if the head isn't ahead of the tail, we don't have any characters
        if (buffer->head == buffer->tail && !buffer->full)
        {
                if (USBD_Available(CDC_ENDPOINT_OUT))
                        accept();
        }
        if (buffer->head == buffer->tail && !buffer->full)
        {
                return -1;
        }
        else
        {
                unsigned char c = buffer->buffer[buffer->tail];
                buffer->tail = (uint32_t)(buffer->tail + 1) % CDC_SERIAL_BUFFER_SIZE;
                buffer->full = false;
                return c;
        }
}

void Serial_::flush(void)
{
        USBD_Flush(CDC_ENDPOINT_IN);
}

size_t Serial_::write(const uint8_t *buffer, size_t size)
{
        /* only try to send bytes if the high-level CDC connection itself
         is open (not just the pipe) - the OS should set lineState when the port
         is opened and clear lineState when the port is closed.
         bytes sent before the user opens the connection or after
         the connection is closed are lost - just like with a UART. */
        if (_usbLineInfo.lineState > 0)  // Problem with Windows(R)
        {
                uint32_t r = USBD_Send(CDC_ENDPOINT_IN, buffer, size);

                if (r == 0) {
                        return r;
                } else {
                        setWriteError();
                        return 0;
                }
         }
        setWriteError();
        return 0;
}

size_t Serial_::write(uint8_t c) {
        return write(&c, 1);
}

// This operator is a convenient way for a sketch to check whether the
// port has actually been configured and opened by the host (as opposed
// to just being connected to the host).  It can be used, for example, in
// setup() before printing to ensure that an application on the host is
// actually ready to receive and display the data.
// We add a short delay before returning to fix a bug observed by Federico
// where the port is configured (lineState != 0) but not quite opened.
Serial_::operator bool()
{
        // this is here to avoid spurious opening after upload
        if (millis() < 500)
                return false;

        bool result = false;

        if (_usbLineInfo.lineState > 0)
        {
                result = true;
        }

        delay(10);
        return result;
}

int32_t Serial_::readBreak() {
        uint8_t enableInterrupts = ((__get_PRIMASK() & 0x1) == 0);

        // disable interrupts,
        // to avoid clearing a breakValue that might occur 
        // while processing the current break value
        __disable_irq();

        int32_t ret = breakValue;

        breakValue = -1;

        if (enableInterrupts) {
                // re-enable the interrupts
                __enable_irq();
        }

        return ret;
}

unsigned long Serial_::baud() {
        return _usbLineInfo.dwDTERate;
}

uint8_t Serial_::stopbits() {
        return _usbLineInfo.bCharFormat;
}

uint8_t Serial_::paritytype() {
        return _usbLineInfo.bParityType;
}

uint8_t Serial_::numbits() {
        return _usbLineInfo.bDataBits;
}

bool Serial_::dtr() {
        return _usbLineInfo.lineState & 0x1;
}

bool Serial_::rts() {
        return _usbLineInfo.lineState & 0x2;
}

Serial_ SerialUSB(USBDevice);

#endif