con_apbuart.c
2.78 KB
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/*
* Copyright (c) 2017, Cobham Gaisler AB
* 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.
*
* 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.
*/
#include "bcc/bcc_param.h"
#include "bcc/bcc.h"
#include "bcc/regs/apbuart.h"
enum {
FIFO_UNKNOWN,
FIFO_YES,
FIFO_NO,
};
static int fifoinfo = FIFO_UNKNOWN;
int __attribute__((weak)) __bcc_con_outbyte(char x)
{
if (0 == __bcc_con_handle) { return 0; }
volatile struct apbuart_regs *regs = (void *) __bcc_con_handle;
int fi;
/* Use transmitter FIFO if available */
again:
fi = fifoinfo;
if (FIFO_YES == fi) {
/* Transmitter FIFO full flag is available */
while (regs->status & APBUART_STATUS_TF);
} else if (FIFO_NO == fi) {
/*
* Transmitter "hold register empty" AKA "FIFO empty" flag is
* available
*/
while (!(regs->status & APBUART_STATUS_HOLD_REGISTER_EMPTY));
} else {
/* First time: probe */
if (regs->ctrl & APBUART_CTRL_FA) {
fifoinfo = FIFO_YES;
} else {
fifoinfo = FIFO_NO;
}
goto again;
}
regs->data = x & 0xff;
return 0;
}
char __attribute__((weak)) __bcc_con_inbyte(void)
{
if (0 == __bcc_con_handle) { return 0; }
volatile struct apbuart_regs *regs = (void *) __bcc_con_handle;
while (0 == (regs->status & APBUART_STATUS_DR));
return regs->data & 0xff;
}