shared/console/uart.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /*
0004  *  Uart driver for Lattice Mico32 (lm32) UART
0005  */
0006
0007 /*
0008  *  COPYRIGHT (c) 1989-1999.
0009  *  On-Line Applications Research Corporation (OAR).
0010  *
0011  * Redistribution and use in source and binary forms, with or without
0012  * modification, are permitted provided that the following conditions
0013  * are met:
0014  * 1. Redistributions of source code must retain the above copyright
0015  *    notice, this list of conditions and the following disclaimer.
0016  * 2. Redistributions in binary form must reproduce the above copyright
0017  *    notice, this list of conditions and the following disclaimer in the
0018  *    documentation and/or other materials provided with the distribution.
0019  *
0020  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0021  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0022  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0023  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0024  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0025  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0026  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0027  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0028  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0029  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0030  * POSSIBILITY OF SUCH DAMAGE.
0031  *
0032  *  Jukka Pietarinen <jukka.pietarinen@mrf.fi>, 2008,
0033  *  Micro-Research Finland Oy
0034  */
0035
0036 #include "../include/system_conf.h"
0037 #include "uart.h"
0038 #include <bsp.h>
0039 #include <rtems/libio.h>
0040
0041 static inline int uartread(unsigned int reg)
0042 {
0043   return *((int*)(UART_BASE_ADDRESS + reg));
0044 }
0045
0046 static inline void uartwrite(unsigned int reg, int value)
0047 {
0048   *((int*)(UART_BASE_ADDRESS + reg)) = value;
0049 }
0050
0051 void BSP_uart_init(int baud)
0052 {
0053   /* Disable UART interrupts */
0054   uartwrite(LM32_UART_IER, 0);
0055
0056   /* Line control 8 bit, 1 stop, no parity */
0057   uartwrite(LM32_UART_LCR, LM32_UART_LCR_8BIT);
0058
0059   /* Modem control, DTR = 1, RTS = 1 */
0060   uartwrite(LM32_UART_MCR, LM32_UART_MCR_DTR | LM32_UART_MCR_RTS);
0061
0062   /* Set baud rate */
0063   uartwrite(LM32_UART_DIV, CPU_FREQUENCY/baud);
0064 }
0065
0066 void BSP_uart_polled_write(char ch)
0067 {
0068   /* Insert CR before LF */
0069   if (ch == '\n')
0070     BSP_uart_polled_write('\r');
0071   /* Wait until THR is empty. */
0072   while (!(uartread(LM32_UART_LSR) & LM32_UART_LSR_THRE));
0073   uartwrite(LM32_UART_RBR, ch);
0074 }
0075
0076 int BSP_uart_polled_read( void )
0077 {
0078   /* Wait until there is a byte in RBR */
0079   while (!(uartread(LM32_UART_LSR) & LM32_UART_LSR_DR));
0080   return (int) uartread(LM32_UART_RBR);
0081 }
0082
0083 char BSP_uart_is_character_ready(char *ch)
0084 {
0085   if (uartread(LM32_UART_LSR) & LM32_UART_LSR_DR)
0086     {
0087       *ch = (char) uartread(LM32_UART_RBR);
0088       return true;
0089     }
0090   *ch = '0';
0091   return false;
0092 }