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/****************************************************************************
* arch/x86/src/qemu/qemu_lowputc.c
*
* Copyright (C) 2011 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 NuttX 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 <arch/io.h>
#include "up_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* COM1 port addresses */
#define COM1_PORT 0x3f8 /* COM1: I/O port 0x3f8, IRQ 4 */
#define COM2_PORT 0x2f8 /* COM2: I/O port 0x2f8, IRQ 3 */
#define COM3_PORT 0x3e8 /* COM3: I/O port 0x3e8, IRQ 4 */
#define COM4_PORT 0x2e8 /* COM4: I/O port 0x2e8, IRQ 3 */
/* 16650 register offsets */
#define COM_RBR 0 /* DLAB=0, Receiver Buffer (read) */
#define COM_THR 0 /* DLAB=0, Transmitter Holding Register (write) */
#define COM_DLL 0 /* DLAB=1, Divisor Latch (least significant byte) */
#define COM_IER 1 /* DLAB=0, Interrupt Enable */
#define COM_DLM 1 /* DLAB=1, Divisor Latch(most significant byte) */
#define COM_IIR 2 /* Interrupt Identification (read) */
#define COM_FCR 2 /* FIFO Control (write) */
#define COM_LCR 3 /* Line Control */
#define COM_MCR 4 /* MODEM Control */
#define COM_LSR 5 /* Line Status */
#define COM_MSR 6 /* MODEM Status */
#define COM_SCR 7 /* Scratch */
/* 16650 register bit definitions */
#define LSR_THRE (1 << 5) /* Bit 5: Transmitter Holding Register Empty */
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/**************************************************************************
* Name: up_lowputc
*
* Description:
* Output one byte on the serial console
*
**************************************************************************/
void up_lowputc(char ch)
{
/* Wait until the Transmitter Holding Register (THR) is empty. */
while ((inb(COM1_PORT+COM_LSR) & LSR_THRE) == 0);
/* Then output the character to the THR*/
outb(ch, COM1_PORT+COM_THR);
}
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