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LibrePilot/flight/PiOS/STM32F10x/pios_usart.c

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/**
******************************************************************************
* @addtogroup PIOS PIOS Core hardware abstraction layer
* @{
* @addtogroup PIOS_USART USART Functions
* @brief PIOS interface for USART port
* @{
*
* @file pios_usart.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* Parts by Thorsten Klose (tk@midibox.org) (tk@midibox.org)
* @brief USART commands. Inits USARTs, controls USARTs & Interupt handlers. (STM32 dependent)
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/* Project Includes */
#include "pios.h"
#if defined(PIOS_INCLUDE_USART)
#include <pios_usart_priv.h>
/* Provide a COM driver */
static void PIOS_USART_ChangeBaud(uint32_t usart_id, uint32_t baud);
static int32_t PIOS_USART_TxBufferPutMoreNonBlocking(uint32_t usart_id, const uint8_t *buffer, uint16_t len);
static int32_t PIOS_USART_TxBufferPutMore(uint32_t usart_id, const uint8_t *buffer, uint16_t len);
static int32_t PIOS_USART_RxBufferGet(uint32_t usart_id);
static int32_t PIOS_USART_RxBufferUsed(uint32_t usart_id);
const struct pios_com_driver pios_usart_com_driver = {
.set_baud = PIOS_USART_ChangeBaud,
.tx_nb = PIOS_USART_TxBufferPutMoreNonBlocking,
.tx = PIOS_USART_TxBufferPutMore,
.rx = PIOS_USART_RxBufferGet,
.rx_avail = PIOS_USART_RxBufferUsed,
};
static bool PIOS_USART_validate(struct pios_usart_dev * usart_dev)
{
return (usart_dev->magic == PIOS_USART_DEV_MAGIC);
}
#if defined(PIOS_INCLUDE_FREERTOS) && 0
static struct pios_usart_dev * PIOS_USART_alloc(void)
{
struct pios_usart_dev * usart_dev;
usart_dev = (struct pios_usart_dev *)malloc(sizeof(*usart_dev));
if (!usart_dev) return(NULL);
usart_dev->magic = PIOS_USART_DEV_MAGIC;
return(usart_dev);
}
#else
static struct pios_usart_dev pios_usart_devs[PIOS_USART_MAX_DEVS];
static uint8_t pios_usart_num_devs;
static struct pios_usart_dev * PIOS_USART_alloc(void)
{
struct pios_usart_dev * usart_dev;
if (pios_usart_num_devs >= PIOS_USART_MAX_DEVS) {
return (NULL);
}
usart_dev = &pios_usart_devs[pios_usart_num_devs++];
usart_dev->magic = PIOS_USART_DEV_MAGIC;
return (usart_dev);
}
#endif
/**
* Initialise a single USART device
*/
int32_t PIOS_USART_Init(uint32_t * usart_id, const struct pios_usart_cfg * cfg)
{
PIOS_DEBUG_Assert(usart_id);
PIOS_DEBUG_Assert(cfg);
struct pios_usart_dev * usart_dev;
usart_dev = (struct pios_usart_dev *) PIOS_USART_alloc();
if (!usart_dev) goto out_fail;
/* Bind the configuration to the device instance */
usart_dev->cfg = cfg;
/* Clear buffer counters */
fifoBuf_init(&usart_dev->rx, usart_dev->rx_buffer, sizeof(usart_dev->rx_buffer));
fifoBuf_init(&usart_dev->tx, usart_dev->tx_buffer, sizeof(usart_dev->tx_buffer));
/* Enable the USART Pins Software Remapping */
if (usart_dev->cfg->remap) {
GPIO_PinRemapConfig(usart_dev->cfg->remap, ENABLE);
}
/* Initialize the USART Rx and Tx pins */
GPIO_Init(usart_dev->cfg->rx.gpio, &usart_dev->cfg->rx.init);
GPIO_Init(usart_dev->cfg->tx.gpio, &usart_dev->cfg->tx.init);
/* Enable USART clock */
switch ((uint32_t)usart_dev->cfg->regs) {
case (uint32_t)USART1:
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
break;
case (uint32_t)USART2:
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
break;
case (uint32_t)USART3:
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
break;
}
/* Configure the USART */
USART_Init(usart_dev->cfg->regs, &usart_dev->cfg->init);
*usart_id = (uint32_t)usart_dev;
/* Configure USART Interrupts */
NVIC_Init(&usart_dev->cfg->irq.init);
USART_ITConfig(usart_dev->cfg->regs, USART_IT_RXNE, ENABLE);
USART_ITConfig(usart_dev->cfg->regs, USART_IT_TXE, ENABLE);
/* Enable USART */
USART_Cmd(usart_dev->cfg->regs, ENABLE);
return(0);
out_fail:
return(-1);
}
/**
* Changes the baud rate of the USART peripheral without re-initialising.
* \param[in] usart_id USART name (GPS, TELEM, AUX)
* \param[in] baud Requested baud rate
*/
static void PIOS_USART_ChangeBaud(uint32_t usart_id, uint32_t baud)
{
struct pios_usart_dev * usart_dev = (struct pios_usart_dev *)usart_id;
bool valid = PIOS_USART_validate(usart_dev);
PIOS_Assert(valid)
USART_InitTypeDef USART_InitStructure;
/* Start with a copy of the default configuration for the peripheral */
USART_InitStructure = usart_dev->cfg->init;
/* Adjust the baud rate */
USART_InitStructure.USART_BaudRate = baud;
/* Write back the new configuration */
USART_Init(usart_dev->cfg->regs, &USART_InitStructure);
}
/**
* Returns number of used bytes in receive buffer
* \param[in] USART USART name
* \return > 0: number of used bytes
* \return 0 if USART not available
*/
static int32_t PIOS_USART_RxBufferUsed(uint32_t usart_id)
{
struct pios_usart_dev * usart_dev = (struct pios_usart_dev *)usart_id;
bool valid = PIOS_USART_validate(usart_dev);
PIOS_Assert(valid)
return (fifoBuf_getUsed(&usart_dev->rx));
}
/**
* Gets a byte from the receive buffer
* \param[in] USART USART name
* \return -1 if no new byte available
* \return >= 0: actual byte received
*/
static int32_t PIOS_USART_RxBufferGet(uint32_t usart_id)
{
struct pios_usart_dev * usart_dev = (struct pios_usart_dev *)usart_id;
bool valid = PIOS_USART_validate(usart_dev);
PIOS_Assert(valid)
if (fifoBuf_getUsed(&usart_dev->rx) == 0) {
/* Nothing new in the buffer */
return -1;
}
/* get byte - this operation should be atomic! */
uint8_t b = fifoBuf_getByte(&usart_dev->rx);
/* Return received byte */
return b;
}
/**
* puts a byte onto the receive buffer
* \param[in] USART USART name
* \param[in] b byte which should be put into Rx buffer
* \return 0 if no error
* \return -1 if buffer full (retry)
*/
static int32_t PIOS_USART_RxBufferPut(uint32_t usart_id, uint8_t b)
{
struct pios_usart_dev * usart_dev = (struct pios_usart_dev *)usart_id;
bool valid = PIOS_USART_validate(usart_dev);
PIOS_Assert(valid)
if (fifoBuf_getFree(&usart_dev->rx) < 1) {
/* Buffer full (retry) */
return -1;
}
/* Copy received byte into receive buffer */
/* This operation should be atomic! */
fifoBuf_putByte(&usart_dev->rx, b);
/* No error */
return 0;
}
/**
* returns number of used bytes in transmit buffer
* \param[in] USART USART name
* \return number of used bytes
* \return 0 if USART not available
*/
static int32_t PIOS_USART_TxBufferUsed(uint32_t usart_id)
{
struct pios_usart_dev * usart_dev = (struct pios_usart_dev *)usart_id;
bool valid = PIOS_USART_validate(usart_dev);
PIOS_Assert(valid)
return (fifoBuf_getUsed(&usart_dev->tx));
}
/**
* gets a byte from the transmit buffer
* \param[in] USART USART name
* \return -1 if no new byte available
* \return >= 0: transmitted byte
*/
static int32_t PIOS_USART_TxBufferGet(uint32_t usart_id)
{
struct pios_usart_dev * usart_dev = (struct pios_usart_dev *)usart_id;
bool valid = PIOS_USART_validate(usart_dev);
PIOS_Assert(valid)
if (fifoBuf_getUsed(&usart_dev->tx) == 0) {
/* Nothing new in the buffer */
return -1;
}
/* get byte - this operation should be atomic! */
PIOS_IRQ_Disable();
uint8_t b = fifoBuf_getByte(&usart_dev->tx);
PIOS_IRQ_Enable();
/* Return received byte */
return b;
}
/**
* puts more than one byte onto the transmit buffer (used for atomic sends)
* \param[in] USART USART name
* \param[in] *buffer pointer to buffer to be sent
* \param[in] len number of bytes to be sent
* \return 0 if no error
* \return -1 if buffer full or cannot get all requested bytes (retry)
*/
static int32_t PIOS_USART_TxBufferPutMoreNonBlocking(uint32_t usart_id, const uint8_t *buffer, uint16_t len)
{
struct pios_usart_dev * usart_dev = (struct pios_usart_dev *)usart_id;
bool valid = PIOS_USART_validate(usart_dev);
PIOS_Assert(valid)
if (len >= fifoBuf_getFree(&usart_dev->tx)) {
/* Buffer cannot accept all requested bytes (retry) */
return -1;
}
/* Copy bytes to be transmitted into transmit buffer */
/* This operation should be atomic! */
PIOS_IRQ_Disable();
uint16_t used = fifoBuf_getUsed(&usart_dev->tx);
fifoBuf_putData(&usart_dev->tx,buffer,len);
if (used == 0) {
/* enable sending when buffer was previously empty */
USART_ITConfig(usart_dev->cfg->regs, USART_IT_TXE, ENABLE);
}
PIOS_IRQ_Enable();
/* No error */
return 0;
}
/**
* puts more than one byte onto the transmit buffer (used for atomic sends)<BR>
* (blocking function)
* \param[in] USART USART name
* \param[in] *buffer pointer to buffer to be sent
* \param[in] len number of bytes to be sent
* \return 0 if no error
*/
static int32_t PIOS_USART_TxBufferPutMore(uint32_t usart_id, const uint8_t *buffer, uint16_t len)
{
int32_t rc;
while ((rc = PIOS_USART_TxBufferPutMoreNonBlocking(usart_id, buffer, len)) == -1);
return rc;
}
void PIOS_USART_IRQ_Handler(uint32_t usart_id)
{
struct pios_usart_dev * usart_dev = (struct pios_usart_dev *)usart_id;
bool valid = PIOS_USART_validate(usart_dev);
PIOS_Assert(valid)
/* Force read of dr after sr to make sure to clear error flags */
volatile uint16_t sr = usart_dev->cfg->regs->SR;
volatile uint8_t dr = usart_dev->cfg->regs->DR;
/* Check if RXNE flag is set */
if (sr & USART_SR_RXNE) {
if (PIOS_USART_RxBufferPut(usart_id, dr) < 0) {
/* Here we could add some error handling */
}
}
/* Check if TXE flag is set */
if (sr & USART_SR_TXE) {
if (PIOS_USART_TxBufferUsed(usart_id) > 0) {
int32_t b = PIOS_USART_TxBufferGet(usart_id);
if (b < 0) {
/* Here we could add some error handling */
usart_dev->cfg->regs->DR = 0xff;
} else {
usart_dev->cfg->regs->DR = b & 0xff;
}
} else {
/* Disable TXE interrupt (TXEIE=0) */
USART_ITConfig(usart_dev->cfg->regs, USART_IT_TXE, DISABLE);
}
}
}
#endif
/**
* @}
* @}
*/