src/flash/ocl/at91sam7x/dcc.c

   1 /***************************************************************************
   2  *   Copyright (C) 2007 by Pavel Chromy                                    *
   3  *   chromy@asix.cz                                                        *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  19  ***************************************************************************/
  20 #include "dcc.h"
  21
  22
  23 /* debug channel read (debugger->MCU) */
  24 uint32 dcc_rd(void)
  25 {
  26         volatile uint32 dcc_reg;
  27
  28         do {
  29                 asm volatile ("mrc p14, 0, %0, C0, C0" : "=r" (dcc_reg) :);
  30         } while ((dcc_reg&1) == 0);
  31
  32         asm volatile ("mrc p14, 0, %0, C1, C0" : "=r" (dcc_reg) :);
  33         return dcc_reg;
  34 }
  35
  36
  37 /* debug channel write (MCU->debugger) */
  38 int dcc_wr(uint32 data)
  39 {
  40         volatile uint32 dcc_reg;
  41
  42         do {
  43                 asm volatile ("mrc p14, 0, %0, C0, C0" : "=r" (dcc_reg) :);
  44                 /* operation controled by master, cancel operation
  45                          upon reception of data for immediate response */
  46                 if (dcc_reg&1) return -1;
  47         } while (dcc_reg&2);
  48
  49         asm volatile ("mcr p14, 0, %0, C1, C0" : : "r" (data));
  50         return 0;
  51 }