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