libgloss/visium/serial-inbyte.c

   1 /* Serial Input for the Visium processor.
   2
   3    Copyright (c) 2015 Rolls-Royce Controls and Data Services Limited.
   4    All rights reserved.
   5
   6    Redistribution and use in source and binary forms, with or without
   7    modification, are permitted provided that the following conditions are met:
   8
   9      * Redistributions of source code must retain the above copyright notice,
  10        this list of conditions and the following disclaimer.
  11      * Redistributions in binary form must reproduce the above copyright
  12        notice, this list of conditions and the following disclaimer in the
  13        documentation and/or other materials provided with the distribution.
  14      * Neither the name of Rolls-Royce Controls and Data Services Limited nor
  15        the names of its contributors may be used to endorse or promote products
  16        derived from this software without specific prior written permission.
  17
  18    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  19    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21    ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  22    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  28    THE POSSIBILITY OF SUCH DAMAGE.  */
  29
  30 char
  31 inbyte (void)
  32 {
  33 #ifdef __VISIUM_ARCH_MCM__
  34   volatile int *const rxdata = (int *) 0x20003920;
  35   volatile int *const rxqs   = (int *) 0x20003930;
  36 #else
  37   volatile int *const rxdata = (int *) 0x20001a20;
  38   volatile int *const rxqs   = (int *) 0x20001a30;
  39 #endif
  40   int bytes_in_fifo = 0;
  41
  42   while (!bytes_in_fifo)
  43     bytes_in_fifo = *rxqs;
  44
  45   /* Read one character.  */
  46   return (*rxdata) & 0xff;
  47 }