| /************************************************************************** |
| * c5471/c5471_lowputc.S |
| * |
| * Copyright (C) 2007 Gregory Nutt. All rights reserved. |
| * Author: Gregory Nutt <spudmonkey@racsa.co.cr> |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * 3. Neither the name Gregory Nutt nor the names of its contributors may be |
| * used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
| * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| * |
| **************************************************************************/ |
| |
| /************************************************************************** |
| * Included Files |
| **************************************************************************/ |
| |
| #include <nuttx/config.h> |
| #include "up_internal.h" |
| #include "up_arch.h" |
| |
| /************************************************************************** |
| * Private Definitions |
| **************************************************************************/ |
| |
| /************************************************************************** |
| * Private Types |
| **************************************************************************/ |
| |
| /************************************************************************** |
| * Private Function Prototypes |
| **************************************************************************/ |
| |
| /************************************************************************** |
| * Global Variables |
| **************************************************************************/ |
| |
| /************************************************************************** |
| * Private Variables |
| **************************************************************************/ |
| |
| /************************************************************************** |
| * Private Functions |
| **************************************************************************/ |
| |
| /************************************************************************** |
| * Public Functions |
| **************************************************************************/ |
| |
| /************************************************************************** |
| * Name: up_lowputc |
| **************************************************************************/ |
| |
| /* This assembly language version has the advantage that it can does not |
| * require a C stack and uses only r0-r1. Hence it can be used during |
| * early boot phases. |
| */ |
| |
| .text |
| .global up_lowputc |
| .type up_lowputc, function |
| up_lowputc: |
| /* On entry, r0 holds the character to be printed */ |
| |
| #ifdef CONFIG_SERIAL_IRDA_CONSOLE |
| ldr r2, =UART_IRDA_BASE /* r2=IRDA UART base */ |
| #else |
| ldr r2, =UART_MODEM_BASE /* r2=Modem UART base */ |
| #endif |
| |
| /* Poll bit 0 of the UART_SSR register. When the bit |
| * is clear, the TX FIFO is no longer full |
| */ |
| |
| 1: ldr r1, [r2, #UART_SSR_OFFS] |
| tst r1, #UART_SSR_TXFULL |
| bne 1b |
| |
| /* Send the character by writing it into the UART_THR |
| * register. |
| */ |
| |
| str r0, [r2, #UART_THR_OFFS] |
| |
| /* Wait for the tranmsit holding regiser (THR) to be |
| * emptied. This is detemined when bit 6 of the LSR |
| * is set. |
| */ |
| |
| 2: ldr r1, [r2, #UART_LSR_OFFS] |
| tst r1, #0x00000020 |
| beq 2b |
| |
| /* If the character that we just sent was a linefeed, |
| * then send a carriage return as well. |
| */ |
| |
| teq r0, #'\n' |
| moveq r0, #'\r' |
| beq 1b |
| |
| /* And return */ |
| |
| mov pc, lr |
| |
