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io.c
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io.c
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/******************************************************************************
*
* Copyright 2014 Altera Corporation. All Rights Reserved.
*
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER "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 AUTHOR 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.
*
******************************************************************************/
/*
* This file contains minimal IO support to make printf work over UART
* The code relies on the Preloader to set the UART module including baud rate
*/
#include <stdio.h>
#include <inttypes.h>
#include "socal/alt_uart.h"
#include "socal/hps.h"
#include "socal/socal.h"
#define STDOUT_FILENO 1
int _close(int file)
{
/* Succeeds only for STDOUT */
return (file == STDOUT_FILENO) ? 0 : -1;
}
int _fstat(int file, void *st)
{
/* Succeeds only for STDOUT */
return (file == STDOUT_FILENO) ? 0 : -1;
}
int _isatty(int file)
{
/* Succeeds only for STDOUT */
return (file == STDOUT_FILENO) ? 1 : -1;
}
off_t _lseek(int file, off_t ptr, int dir)
{
/* Succeeds only for STDOUT */
return (file == STDOUT_FILENO) ? 0 : -1;
}
int _read(int file, void *ptr, size_t len)
{
/* Always fails */
return -1;
}
int _write(int file, char * ptr, unsigned len, int flag )
{
/* Fails if not STDOUT */
if(file != STDOUT_FILENO)
{
return -1;
}
/* Print each character to UART */
for(int i=0; i<len; i++)
{
/* Wait until THR is empty*/
while(1 != ALT_UART_LSR_THRE_GET(alt_read_word(ALT_UART0_LSR_ADDR)))
{
}
/* Write character to THR */
alt_write_word(ALT_UART0_RBR_THR_DLL_ADDR, ptr[i]);
}
/* All printed fine */
return len;
}