radio/src/dmafifo.h

   1 /*
   2  * Copyright (C) OpenTX
   3  *
   4  * Based on code named
   5  *   th9x - http://code.google.com/p/th9x
   6  *   er9x - http://code.google.com/p/er9x
   7  *   gruvin9x - http://code.google.com/p/gruvin9x
   8  *
   9  * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  */
  20
  21 #ifndef _DMA_FIFO_H_
  22 #define _DMA_FIFO_H_
  23
  24 #include "definitions.h"
  25
  26 template <int N>
  27 class DMAFifo
  28 {
  29   public:
  30     DMAFifo(DMA_Stream_TypeDef * stream):
  31       stream(stream),
  32       ridx(0)
  33     {
  34     }
  35
  36     void clear()
  37     {
  38       ridx = 0;
  39     }
  40
  41     uint32_t size()
  42     {
  43       return N;
  44     }
  45
  46     uint8_t last(int index)
  47     {
  48       return fifo[(2*N - stream->NDTR - index) & (N-1)];
  49     }
  50
  51     bool isEmpty()
  52     {
  53 #if defined(SIMU)
  54       return true;
  55 #endif
  56       return (ridx == N - stream->NDTR);
  57     }
  58
  59     bool pop(uint8_t & element)
  60     {
  61       if (isEmpty()) {
  62         return false;
  63       }
  64       else {
  65         element = fifo[ridx];
  66         ridx = (ridx+1) & (N-1);
  67         return true;
  68       }
  69     }
  70
  71     uint8_t * buffer()
  72     {
  73       return fifo;
  74     }
  75
  76   protected:
  77     uint8_t fifo[N];
  78     DMA_Stream_TypeDef * stream;
  79     volatile uint32_t ridx;
  80 };
  81
  82 #endif // _DMA_FIFO_H_