/****************************************************************************
*
* Copyright (c) 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 interface_serial.cpp
*
* Serial interface for PX4IO
*/
/* XXX trim includes */
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <assert.h>
#include <debug.h>
#include <time.h>
#include <errno.h>
#include <string.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 <debug.h>
#include <systemlib/hx_stream.h>
#include "interface.h"
class PX4IO_serial : public PX4IO_interface
{
public:
PX4IO_serial(int port);
virtual ~PX4IO_serial();
virtual int set_reg(uint8_t page, uint8_t offset, const uint16_t *values, unsigned num_values);
virtual int get_reg(uint8_t page, uint8_t offset, uint16_t *values, unsigned num_values);
virtual bool ok();
private:
volatile uint32_t *_serial_base;
int _vector;
uint8_t *_tx_buf;
unsigned _tx_size;
const uint8_t *_rx_buf;
unsigned _rx_size;
hx_stream_t _stream;
sem_t _bus_semaphore;
sem_t _completion_semaphore;
/**
* Send _tx_size bytes from the buffer, then
* if _rx_size is greater than zero wait for a packet
* to come back.
*/
int _wait_complete();
/**
* Interrupt handler.
*/
static int _interrupt(int irq, void *context);
void _do_interrupt();
/**
* Stream transmit callback
*/
static void _tx(void *arg, uint8_t data);
void _do_tx(uint8_t data);
/**
* Stream receive callback
*/
static void _rx(void *arg, const void *data, size_t length);
void _do_rx(const uint8_t *data, size_t length);
/**
* Serial register accessors.
*/
volatile uint32_t &_sreg(unsigned offset)
{
return *(_serial_base + (offset / sizeof(uint32_t)));
}
volatile uint32_t &_SR() { return _sreg(STM32_USART_SR_OFFSET); }
volatile uint32_t &_DR() { return _sreg(STM32_USART_DR_OFFSET); }
volatile uint32_t &_BRR() { return _sreg(STM32_USART_BRR_OFFSET); }
volatile uint32_t &_CR1() { return _sreg(STM32_USART_CR1_OFFSET); }
volatile uint32_t &_CR2() { return _sreg(STM32_USART_CR2_OFFSET); }
volatile uint32_t &_CR3() { return _sreg(STM32_USART_CR3_OFFSET); }
volatile uint32_t &_GTPR() { return _sreg(STM32_USART_GTPR_OFFSET); }
};
/* XXX hack to avoid expensive IRQ lookup */
static PX4IO_serial *io_serial;
PX4IO_interface *io_serial_interface(int port)
{
return new PX4IO_serial(port);
}
PX4IO_serial::PX4IO_serial(int port) :
_serial_base(0),
_vector(0),
_tx_buf(nullptr),
_tx_size(0),
_rx_size(0),
_stream(0)
{
/* only allow one instance */
if (io_serial != nullptr)
return;
switch (port) {
case 5:
_serial_base = (volatile uint32_t *)STM32_UART5_BASE;
_vector = STM32_IRQ_UART5;
break;
default:
/* not a supported port */
return;
}
/* XXX need to configure the port here */
/* need space for worst-case escapes + hx protocol overhead */
/* XXX this is kinda gross, but hx transmits a byte at a time */
_tx_buf = new uint8_t[HX_STREAM_MAX_FRAME];
irq_attach(_vector, &_interrupt);
_stream = hx_stream_init(-1, _rx, this);
sem_init(&_completion_semaphore, 0, 0);
sem_init(&_bus_semaphore, 0, 1);
}
PX4IO_serial::~PX4IO_serial()
{
if (_tx_buf != nullptr)
delete[] _tx_buf;
if (_vector)
irq_detach(_vector);
if (io_serial == this)
io_serial = nullptr;
if (_stream)
hx_stream_free(_stream);
sem_destroy(&_completion_semaphore);
sem_destroy(&_bus_semaphore);
}
bool
PX4IO_serial::ok()
{
if (_serial_base == 0)
return false;
if (_vector == 0)
return false;
if (_tx_buf == nullptr)
return false;
if (!_stream)
return false;
return true;
}
int
PX4IO_serial::set_reg(uint8_t page, uint8_t offset, const uint16_t *values, unsigned num_values)
{
unsigned count = num_values * sizeof(*values);
if (count > (HX_STREAM_MAX_FRAME - 2))
return -EINVAL;
sem_wait(&_bus_semaphore);
_tx_buf[0] = page;
_tx_buf[1] = offset;
memcpy(&_tx_buf[2], (void *)values, count);
_tx_size = count + 2;
_rx_size = 0;
/* start the transaction and wait for it to complete */
int result = _wait_complete();
sem_post(&_bus_semaphore);
return result;
}
int
PX4IO_serial::get_reg(uint8_t page, uint8_t offset, uint16_t *values, unsigned num_values)
{
unsigned count = num_values * sizeof(*values);
if (count > HX_STREAM_MAX_FRAME)
return -EINVAL;
sem_wait(&_bus_semaphore);
_tx_buf[0] = page;
_tx_buf[1] = offset;
_tx_buf[2] = num_values;
_tx_size = 3; /* this tells IO that this is a read request */
_rx_size = count;
/* start the transaction and wait for it to complete */
int result = _wait_complete();
if (result != OK)
goto out;
/* compare the received count with the expected count */
if (_rx_size != count) {
return -EIO;
} else {
/* copy back the result */
memcpy(values, &_rx_buf[0], count);
}
out:
sem_post(&_bus_semaphore);
return OK;
}
int
PX4IO_serial::_wait_complete()
{
/* prepare the stream for transmission (also discards any received noise) */
hx_stream_reset(_stream);
hx_stream_start(_stream, _tx_buf, _tx_size);
/* enable transmit-ready interrupt, which will start transmission */
_CR1() |= USART_CR1_TXEIE;
/* compute the deadline for a 5ms timeout */
struct timespec abstime;
clock_gettime(CLOCK_REALTIME, &abstime);
abstime.tv_nsec += 5000000; /* 5ms timeout */
while (abstime.tv_nsec > 1000000000) {
abstime.tv_sec++;
abstime.tv_nsec -= 1000000000;
}
/* wait for the transaction to complete */
int ret = sem_timedwait(&_completion_semaphore, &abstime);
return ret;
}
int
PX4IO_serial::_interrupt(int irq, void *context)
{
/* ... because NuttX doesn't give us a handle per vector */
io_serial->_do_interrupt();
return 0;
}
void
PX4IO_serial::_do_interrupt()
{
uint32_t sr = _SR();
/* handle transmit completion */
if (sr & USART_SR_TXE) {
int c = hx_stream_send_next(_stream);
if (c == -1) {
/* no more bytes to send, not interested in interrupts now */
_CR1() &= ~USART_CR1_TXEIE;
/* was this a tx-only operation? */
if (_rx_size == 0) {
/* wake up waiting sender */
sem_post(&_completion_semaphore);
}
} else {
_DR() = c;
}
}
if (sr & USART_SR_RXNE) {
uint8_t c = _DR();
hx_stream_rx(_stream, c);
}
}
void
PX4IO_serial::_rx(void *arg, const void *data, size_t length)
{
PX4IO_serial *pserial = reinterpret_cast<PX4IO_serial *>(arg);
pserial->_do_rx((const uint8_t *)data, length);
}
void
PX4IO_serial::_do_rx(const uint8_t *data, size_t length)
{
_rx_buf = data;
if (length < _rx_size)
_rx_size = length;
/* notify waiting receiver */
sem_post(&_completion_semaphore);
}
