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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [libgloss/] [or32/] [uart.c] - Blame information for rev 247

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Line No. Rev Author Line
1 207 jeremybenn
/* uart.c. UART support functions
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   Copyright (C) 2004, Jacob Bower
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   Copyright (C) 2010, Embecosm Limited <info@embecosm.com>
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   Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>
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   This file is part of Newlib.
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   The original work by Jacob Bower is provided as-is without any kind of
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   warranty. Use it at your own risk!
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   All subsequent work is bound by version 3 of the GPL as follows.
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   This program is free software; you can redistribute it and/or modify it
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   under the terms of the GNU General Public License as published by the Free
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   Software Foundation; either version 3 of the License, or (at your option)
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   any later version.
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   This program is distributed in the hope that it will be useful, but WITHOUT
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   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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   more details.
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   You should have received a copy of the GNU General Public License along
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   with this program.  If not, see <http:#www.gnu.org/licenses/>.             */
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/* -------------------------------------------------------------------------- */
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/* This program is commented throughout in a fashion suitable for processing
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   with Doxygen.                                                              */
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/* -------------------------------------------------------------------------- */
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#include "or1ksim-board.h"
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#include "uart.h"
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/*! Macro to access a UART register */
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#define UREG8(reg) REG8 (UART_BASE + reg)
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/*! Macro to check if transmit and transmit holding registers are both empty. */
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#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
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/*! Macro to wait until a char has been transmitted */
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#define WAIT_FOR_XMITR                          \
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  do                                            \
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    {                                           \
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      lsr = UREG8 (UART_LSR);                   \
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    }                                           \
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  while ((lsr & BOTH_EMPTY) != BOTH_EMPTY)
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/*! Macro to wait until a char can be transmitted */
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#define WAIT_FOR_THRE                           \
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  do                                            \
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    {                                           \
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      lsr = UREG8 (UART_LSR);                   \
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    }                                           \
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  while ((lsr & UART_LSR_THRE) != UART_LSR_THRE)
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/* Macro to see if a character has been received */
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#define CHECK_FOR_CHAR (UREG8 (UART_LSR) & UART_LSR_DR)
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/* Macro to wait until a character is received */
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#define WAIT_FOR_CHAR \
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         do { \
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                lsr = UREG8 (UART_LSR); \
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         } while ((lsr & UART_LSR_DR) != UART_LSR_DR)
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/* -------------------------------------------------------------------------- */
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/*!Initialize the UART                                                        */
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/* -------------------------------------------------------------------------- */
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void
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_uart_init ()
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{
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        int divisor;
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        /* Reset receiver and transmiter */
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        UREG8 (UART_FCR) = UART_FCR_ENABLE_FIFO |
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                           UART_FCR_CLEAR_RCVR  |
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                           UART_FCR_CLEAR_XMIT  |
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                           UART_FCR_TRIGGER_14;
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        /* Disable all interrupts */
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        UREG8 (UART_IER) = 0x00;
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        /* Set 8 bit char, 1 stop bit, no parity */
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        UREG8 (UART_LCR) = UART_LCR_WLEN8 & ~(UART_LCR_STOP | UART_LCR_PARITY);
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        /* Set baud rate */
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        divisor = IN_CLK / (16 * UART_BAUD_RATE);
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        UREG8 (UART_LCR) |= UART_LCR_DLAB;
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        UREG8 (UART_DLL)  = divisor & 0x000000ff;
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        UREG8 (UART_DLM)  = (divisor >> 8) & 0x000000ff;
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        UREG8 (UART_LCR) &= ~(UART_LCR_DLAB);
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}       /* _uart_init () */
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/* -------------------------------------------------------------------------- */
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/*!Put a character out on the UART
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   @param[in] c  The character to output                                      */
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/* -------------------------------------------------------------------------- */
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void _uart_putc (char  c)
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{
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  unsigned char lsr;
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  /* Wait until we are free to transmit */
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  WAIT_FOR_THRE;
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  /* Put the character to be transmitted and wait until it has gone. */
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  UREG8 (UART_TX) = c;
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  WAIT_FOR_XMITR;
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}       /* _uart_putc () */
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/* -------------------------------------------------------------------------- */
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/*!Get a character from the UART
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   @reurn  The character read.                                                */
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/* -------------------------------------------------------------------------- */
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char
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_uart_getc ()
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{
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  unsigned char lsr;
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  char c;
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  /* Wait until a char is available, then get it. */
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  WAIT_FOR_CHAR;
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  return  UREG8 (UART_RX);
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}       /* _uart_getc () */

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