1/*
2 *
3 * BRIEF MODULE DESCRIPTION
4 *	Low level uart routines to directly access a 16550 uart.
5 *
6 * Copyright 2001 MontaVista Software Inc.
7 * Author: MontaVista Software, Inc.
8 *         	ppopov@mvista.com or source@mvista.com
9 *
10 *  This program is free software; you can redistribute  it and/or modify it
11 *  under  the terms of  the GNU General  Public License as published by the
12 *  Free Software Foundation;  either version 2 of the  License, or (at your
13 *  option) any later version.
14 *
15 *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
16 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
17 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
18 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
19 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
21 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
22 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
23 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 *  You should have received a copy of the  GNU General Public License along
27 *  with this program; if not, write  to the Free Software Foundation, Inc.,
28 *  675 Mass Ave, Cambridge, MA 02139, USA.
29 */
30
31#include <linux/types.h>
32#include <asm/mach-au1x00/au1000.h>
33
34#define SERIAL_BASE   UART_BASE
35#define SER_CMD       0x7
36#define SER_DATA      0x1
37#define TX_BUSY       0x20
38
39#define TIMEOUT       0xffffff
40#define SLOW_DOWN
41
42static volatile unsigned long * const com1 = (unsigned long *)SERIAL_BASE;
43
44
45#ifdef SLOW_DOWN
46static inline void slow_down(void)
47{
48    int k;
49    for (k=0; k<10000; k++);
50}
51#else
52#define slow_down()
53#endif
54
55void
56prom_putchar(const unsigned char c)
57{
58    unsigned char ch;
59    int i = 0;
60
61    do {
62        ch = com1[SER_CMD];
63        slow_down();
64        i++;
65        if (i>TIMEOUT) {
66            break;
67        }
68    } while (0 == (ch & TX_BUSY));
69    com1[SER_DATA] = c;
70}
71