LXR linux/arch/mips/alchemy/common/puts.c

   1/*
   2 *
   3 * BRIEF MODULE DESCRIPTION
   4 *      Low level UART routines to directly access Alchemy UART.
   5 *
   6 * Copyright 2001, 2008 MontaVista Software Inc.
   7 * Author: MontaVista Software, Inc. <source@mvista.com>
   8 *
   9 *  This program is free software; you can redistribute  it and/or modify it
  10 *  under  the terms of  the GNU General  Public License as published by the
  11 *  Free Software Foundation;  either version 2 of the  License, or (at your
  12 *  option) any later version.
  13 *
  14 *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
  15 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
  16 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  17 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
  18 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
  20 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  21 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
  22 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24 *
  25 *  You should have received a copy of the  GNU General Public License along
  26 *  with this program; if not, write  to the Free Software Foundation, Inc.,
  27 *  675 Mass Ave, Cambridge, MA 02139, USA.
  28 */
  29
  30#include <asm/mach-au1x00/au1000.h>
  31
  32#define SERIAL_BASE   UART_BASE
  33#define SER_CMD       0x7
  34#define SER_DATA      0x1
  35#define TX_BUSY       0x20
  36
  37#define TIMEOUT       0xffffff
  38#define SLOW_DOWN
  39
  40static volatile unsigned long * const com1 = (unsigned long *)SERIAL_BASE;
  41
  42#ifdef SLOW_DOWN
  43static inline void slow_down(void)
  44{
  45        int k;
  46
  47        for (k = 0; k < 10000; k++);
  48}
  49#else
  50#define slow_down()
  51#endif
  52
  53void
  54prom_putchar(const unsigned char c)
  55{
  56        unsigned char ch;
  57        int i = 0;
  58
  59        do {
  60                ch = com1[SER_CMD];
  61                slow_down();
  62                i++;
  63                if (i > TIMEOUT)
  64                        break;
  65        } while (0 == (ch & TX_BUSY));
  66
  67        com1[SER_DATA] = c;
  68}
  69