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/****************************************************************************
*
* Copyright (C) 2012,2013 PX4 Development Team. 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. Neither the name PX4 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.
*
****************************************************************************/
/**
* @file serial.c
*
* Serial communication for the PX4IO module.
*/
#include <stdint.h>
#include <unistd.h>
#include <termios.h>
#include <fcntl.h>
#include <string.h>
#include <nuttx/arch.h>
#include <arch/board/board.h>
/* XXX might be able to prune these */
#include <chip.h>
#include <up_internal.h>
#include <up_arch.h>
#include <stm32_internal.h>
#include <systemlib/hx_stream.h>
//#define DEBUG
#include "px4io.h"
static hx_stream_t if_stream;
static volatile bool sending = false;
static int serial_interrupt(int vector, void *context);
static void serial_callback(void *arg, const void *data, unsigned length);
/* serial register accessors */
#define REG(_x) (*(volatile uint32_t *)(SERIAL_BASE + _x))
#define rSR REG(STM32_USART_SR_OFFSET)
#define rDR REG(STM32_USART_DR_OFFSET)
#define rBRR REG(STM32_USART_BRR_OFFSET)
#define rCR1 REG(STM32_USART_CR1_OFFSET)
#define rCR2 REG(STM32_USART_CR2_OFFSET)
#define rCR3 REG(STM32_USART_CR3_OFFSET)
#define rGTPR REG(STM32_USART_GTPR_OFFSET)
void
interface_init(void)
{
/* XXX do serial port init here */
irq_attach(SERIAL_VECTOR, serial_interrupt);
if_stream = hx_stream_init(-1, serial_callback, NULL);
/* XXX add stream stats counters? */
debug("serial init");
}
void
interface_tick()
{
/* XXX nothing interesting to do here */
}
static int
serial_interrupt(int vector, void *context)
{
uint32_t sr = rSR;
if (sr & USART_SR_TXE) {
int c = hx_stream_send_next(if_stream);
if (c == -1) {
/* no more bytes to send, not interested in interrupts now */
rCR1 &= ~USART_CR1_TXEIE;
sending = false;
} else {
rDR = c;
}
}
if (sr & USART_SR_RXNE) {
uint8_t c = rDR;
hx_stream_rx(if_stream, c);
}
return 0;
}
static void
serial_callback(void *arg, const void *data, unsigned length)
{
const uint8_t *message = (const uint8_t *)data;
/* malformed frame, ignore it */
if (length < 2)
return;
/* we got a new request while we were still sending the last reply - not supported */
if (sending)
return;
/* reads are page / offset / length */
if (length == 3) {
uint16_t *registers;
unsigned count;
/* get registers for response, send an empty reply on error */
if (registers_get(message[0], message[1], ®isters, &count) < 0)
count = 0;
/* constrain count to requested size or message limit */
if (count > message[2])
count = message[2];
if (count > HX_STREAM_MAX_FRAME)
count = HX_STREAM_MAX_FRAME;
/* start sending the reply */
sending = true;
hx_stream_reset(if_stream);
hx_stream_start(if_stream, registers, count * 2 + 2);
/* enable the TX-ready interrupt */
rCR1 |= USART_CR1_TXEIE;
return;
} else {
/* it's a write operation, pass it to the register API */
registers_set(message[0],
message[1],
(const uint16_t *)&message[2],
(length - 2) / 2);
}
}
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