PlutoTX.hxx

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#pragma once
/*
Copyright (c) 2026 Matthew H. Reilly (kb1vc)
All rights reserved.
 
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
 
    Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
    Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in
    the documentation and/or other materials provided with the
    distribution.
 
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

 
#include "RadioTX.hxx"
#include "SoDaBase.hxx"
#include "Params.hxx"
#include <SoDa/ReSampler.hxx>
#include <iio.h>
#include <memory>
#include <vector>
#include <complex>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <deque>
 
namespace SoDa {
  class PlutoTX;
  typedef std::shared_ptr<PlutoTX> PlutoTXPtr;
 
  class PlutoTX : public RadioTX {
  protected:
    PlutoTX(ParamsPtr params);
 
  public:
    ~PlutoTX();
 
    static PlutoTXPtr make(ParamsPtr params) {
      auto ret = std::shared_ptr<PlutoTX>(new PlutoTX(params));
      ret->self = ret;
      ret->registerThread(ret);
      return ret;
    }
 
    void init() override;

    bool transmitSwitch(bool tx_on) override;

    bool put(CBufPtr buf) override;
 
    RadioTXPtr getSelfPtr() override { return self.lock(); }
 
  private:
    void pushToHW(const std::vector<std::complex<float>> & block);
    void flushZeros();
    void ioThreadFn();
    void enqueue(std::vector<std::complex<float>> block);
 
    // Kernel DMA slots; IO thread pre-fills (N_KERNEL_BUFS-1) on TX arm.
    // 120000 samples / 2.5 MSPS = 48 ms each → 4 × 48 ms = 192 ms headroom.
    static constexpr unsigned int N_KERNEL_BUFS = 5;
    // Software queue cap: prevents RadioTX from flooding the IO thread.
    static constexpr unsigned int MAX_SW_QUEUE  = 16;
 
    // IIO streaming objects — owned by the IO thread after init().
    iio_context * ctx;
    iio_device  * dev;
    iio_channel * tx_i_chan;
    iio_channel * tx_q_chan;
    iio_buffer  * txbuf;
 
    unsigned int hw_buf_size;
    unsigned int rs_in_size;
 
    SoDa::ReSamplerPtr hw_resampler;
 
    std::vector<std::complex<float>> accu;   
    std::vector<std::complex<float>> rs_in;  
    std::vector<std::complex<float>> hw_cf;  
 
    std::weak_ptr<PlutoTX> self;
 
    // Async IO: dedicated thread drains tx_queue via iio_buffer_push() so
    // RadioTX::put() never blocks on USB scheduling jitter.
    std::thread                                  io_thread;
    std::mutex                                   tx_mutex;
    std::condition_variable                      tx_cv;
    std::deque<std::vector<std::complex<float>>> tx_queue;
    bool                                         io_running{false};
  };
}