File content as of revision 4:e518dde96e59:

/**
 * @file    BufferedSpi.cpp
 * @brief   Software Buffer - Extends mbed SPI functionallity
 * @author  Armelle Duboc
 * @version 1.0
 * @see
 *
 * Copyright (c) STMicroelectronics 2017
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "BufferedSpi.h"
#include <stdarg.h>
#include "mbed_debug.h"
#include "mbed_error.h"

// change to true to add few SPI debug lines
#define local_debug false

extern "C" int BufferedPrintfC(void *stream, int size, const char *format, va_list arg);

void BufferedSpi::DatareadyRising(void)
{
    if (_cmddata_rdy_rising_event == 1) {
        _cmddata_rdy_rising_event = 0;
    }
}

int BufferedSpi::wait_cmddata_rdy_high(void)
{
    Timer timer;
    timer.start();

    /* wait for dataready = 1 */
    while (dataready.read() == 0) {
        if (timer.read_ms() > _timeout) {
            debug_if(local_debug, "ERROR: SPI write timeout\r\n");
            return -1;
        }
    }

    _cmddata_rdy_rising_event = 1;

    return 0;
}

int BufferedSpi::wait_cmddata_rdy_rising_event(void)
{
    Timer timer;
    timer.start();

    while (_cmddata_rdy_rising_event == 1) {
        if (timer.read_ms() > _timeout) {
            _cmddata_rdy_rising_event = 0;
            if (dataready.read() == 1) {
                debug_if(local_debug, "ERROR: We missed rising event !! (timemout=%d)\r\n", _timeout);
            }
            debug_if(local_debug, "ERROR: SPI read timeout\r\n");
            return -1;
        }
    }

    return 0;
}

BufferedSpi::BufferedSpi(PinName mosi, PinName miso, PinName sclk, PinName _nss, PinName _datareadypin,
                         uint32_t buf_size, uint32_t tx_multiple, const char *name)
    : SPI(mosi, miso, sclk, NC), nss(_nss),  _txbuf((uint32_t)(tx_multiple * buf_size)), _rxbuf(buf_size), dataready(_datareadypin)
{
    this->_buf_size = buf_size;
    this->_tx_multiple = tx_multiple;
    this->_sigio_event = 0;

    _datareadyInt = new InterruptIn(_datareadypin);
    _datareadyInt->rise(callback(this, &BufferedSpi::DatareadyRising));

    _cmddata_rdy_rising_event = 1;

    return;
}

BufferedSpi::~BufferedSpi(void)
{

    return;
}

void BufferedSpi::frequency(int hz)
{
    SPI::frequency(hz);
}

void BufferedSpi::format(int bits, int mode)
{
    SPI::format(bits, mode);
}

void BufferedSpi::disable_nss()
{
    nss = 1;
    wait_us(15);
}

void BufferedSpi::enable_nss()
{
    nss = 0;
    wait_us(15);
}

int BufferedSpi::readable(void)
{
    return _rxbuf.available();  // note: look if things are in the buffer
}

int BufferedSpi::writeable(void)
{
    return 1;   // buffer allows overwriting by design, always true
}

int BufferedSpi::getc(void)
{
    if (_rxbuf.available()) {
        return _rxbuf;
    } else {
        return -1;
    }
}

int BufferedSpi::putc(int c)
{
    _txbuf = (char)c;

    return c;
}

void BufferedSpi::flush_txbuf(void)
{
    _txbuf.clear();
}

int BufferedSpi::puts(const char *s)
{
    if (s != NULL) {
        const char *ptr = s;

        while (*(ptr) != 0) {
            _txbuf = *(ptr++);
        }
        _txbuf = '\n';  // done per puts definition
        BufferedSpi::txIrq();                // only write to hardware in one place
        return (ptr - s) + 1;
    }
    return 0;
}

extern "C" size_t BufferedSpiThunk(void *buf_spi, const void *s, size_t length)
{
    BufferedSpi *buffered_spi = (BufferedSpi *)buf_spi;
    return buffered_spi->buffwrite(s, length);
}

int BufferedSpi::printf(const char *format, ...)
{
    va_list arg;
    va_start(arg, format);
    int r = BufferedPrintfC((void *)this, this->_buf_size, format, arg);
    va_end(arg);
    return r;
}

ssize_t BufferedSpi::buffwrite(const void *s, size_t length)
{
    /* flush buffer from previous message */
    this->flush_txbuf();

    if (wait_cmddata_rdy_high() < 0) {
        debug_if(local_debug, "BufferedSpi::buffwrite timeout (%d)\r\n", _timeout);
        return -1;
    }

    this->enable_nss();

    if (s != NULL && length > 0) {
        /* 1st fill _txbuf */
        const char *ptr = (const char *)s;
        const char *end = ptr + length;

        while (ptr != end) {
            _txbuf = *(ptr++);
        }
        if (length & 1) { /* padding to send the last char */
            _txbuf = '\n';
            length++;
        }

        /* 2nd write in SPI */
        BufferedSpi::txIrq();                // only write to hardware in one place

        this->disable_nss();
        return ptr - (const char *)s;
    }
    this->disable_nss();

    return 0;
}

ssize_t BufferedSpi::buffsend(size_t length)
{
    /* wait for dataready = 1 */
    if (wait_cmddata_rdy_high() < 0) {
        debug_if(local_debug, "BufferedSpi::buffsend timeout (%d)\r\n", _timeout);
        return -1;
    }

    this->enable_nss();

    /* _txbuffer is already filled with data to send */
    /* check if _txbuffer needs padding to send the last char */
    if (length & 1) {
        _txbuf = '\n';
        length++;
    }
    BufferedSpi::txIrq();                // only write to hardware in one place

    this->disable_nss();

    return length;
}

ssize_t BufferedSpi::read()
{
    return this->read(0);
}

ssize_t BufferedSpi::read(uint32_t max)
{
    uint32_t len = 0;
    uint8_t FirstRemoved = 1;
    int tmp;

    disable_nss();

    /* wait for data ready is up */
    if (wait_cmddata_rdy_rising_event() != 0) {
        debug_if(local_debug, "BufferedSpi::read timeout (%d)\r\n", _timeout);
        return -1;
    }

    enable_nss();
    while (dataready.read() == 1 && (len < (_buf_size - 2))) {
        tmp = SPI::write(0xAA);  // dummy write to receive 2 bytes

        if (!((len == 0) && (tmp == 0x0A0D) && (FirstRemoved))) {
            /* do not take into account the 2 firts \r \n char in the buffer */
            if ((max == 0) || (len < max)) {
                _rxbuf = (char)(tmp & 0x00FF);
                _rxbuf = (char)((tmp >> 8) & 0xFF);
                len += 2;
            }
        } else {
            FirstRemoved = 0;
        }
    }
    disable_nss();

    if (len >= _buf_size) {
        debug_if(local_debug, "firmware ERROR ES_WIFI_ERROR_STUFFING_FOREVER\r\n");
        return -1;
    }

    debug_if(local_debug, "SPI READ %d BYTES\r\n", len);

    return len;
}

void BufferedSpi::txIrq(void)
{
    /* write everything available in the _txbuffer */
    int value = 0;
    int dbg_cnt = 0;
    while (_txbuf.available() && (_txbuf.getNbAvailable() > 0)) {
        value = _txbuf.get();
        if (_txbuf.available() && ((_txbuf.getNbAvailable() % 2) != 0)) {
            value |= ((_txbuf.get() << 8) & 0XFF00);
            SPI::write(value);
            dbg_cnt++;
        }
    }
    debug_if(local_debug, "SPI Sent %d BYTES\r\n", 2 * dbg_cnt);
    // disable the TX interrupt when there is nothing left to send
    BufferedSpi::attach(NULL, BufferedSpi::TxIrq);
    // trigger callback if necessary
    if (_cbs[TxIrq]) {
        _cbs[TxIrq]();
    }
    return;
}

void BufferedSpi::prime(void)
{
    BufferedSpi::txIrq();                // only write to hardware in one place
    return;
}

void BufferedSpi::attach(Callback<void()> func, IrqType type)
{
    _cbs[type] = func;
}

void BufferedSpi::sigio(Callback<void()> func)
{
    core_util_critical_section_enter();
    _sigio_cb = func;
    if (_sigio_cb) {
        if (_sigio_event == 1) {
            _sigio_cb();
            _sigio_event = 0;
        }
    }
    core_util_critical_section_exit();
}