text: /*
   * Copyright (C) 2018 bzt (bztsrc@github)
   *
   * 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.
   *
   */
  
  /* a properly aligned buffer */
  extern volatile unsigned int mbox[36];
  
  #define MBOX_REQUEST    0
  
  /* channels */
  #define MBOX_CH_POWER   0
  #define MBOX_CH_FB      1
  #define MBOX_CH_VUART   2
  #define MBOX_CH_VCHIQ   3
  #define MBOX_CH_LEDS    4
  #define MBOX_CH_BTNS    5
  #define MBOX_CH_TOUCH   6
  #define MBOX_CH_COUNT   7
  #define MBOX_CH_PROP    8
  
  /* tags */
  #define MBOX_TAG_GETSERIAL      0x10004
  #define MBOX_TAG_LAST           0
  
  int mbox_call(unsigned char ch);
  