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/*
* FreeRTOS Kernel V10.3.0
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/* Basic interrupt driven serial port driver for uart1.
*/
/* Standard includes. */
#include <stdlib.h>
/* Kernel includes. */
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"
/* Demo application includes. */
#include <machine/uart.h>
#include <machine/ic.h>
#include "serial.h"
/*-----------------------------------------------------------*/
#define comBLOCK_RETRY_TIME 10
/*-----------------------------------------------------------*/
/* The interrupt handlers are naked functions that call C handlers. The C
handlers are marked as noinline to ensure they work correctly when the
optimiser is on. */
void interrupt5_handler( void ) __attribute__((naked));
static void prvTxHandler( void ) __attribute__((noinline));
void interrupt6_handler( void ) __attribute__((naked));
static void prvRxHandler( void ) __attribute__((noinline));
/*-----------------------------------------------------------*/
/* Queues used to hold received characters, and characters waiting to be
transmitted. */
static QueueHandle_t xRxedChars;
static QueueHandle_t xCharsForTx;
/*-----------------------------------------------------------*/
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
/* Create the queues used to hold Rx and Tx characters. */
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
if( ( xRxedChars ) && ( xCharsForTx ) )
{
/* Set up interrupts */
/* tx interrupt will be enabled when we need to send something */
uart1->tx_mask = 0;
uart1->rx_mask = 1;
irq[IRQ_UART1_TX].ien = 1;
irq[IRQ_UART1_RX].ien = 1;
}
return ( xComPortHandle ) 0;
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
{
/* The port handle is not required as this driver only supports uart1. */
(void) pxPort;
/* Get the next character from the buffer. Return false if no characters
are available, or arrive before xBlockTime expires. */
if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
{
return pdTRUE;
}
else
{
return pdFALSE;
}
}
/*-----------------------------------------------------------*/
void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
{
int i;
signed char *pChNext;
/* Send each character in the string, one at a time. */
pChNext = ( signed char * )pcString;
for( i = 0; i < usStringLength; i++ )
{
/* Block until character has been transmitted. */
while( xSerialPutChar( pxPort, *pChNext, comBLOCK_RETRY_TIME ) != pdTRUE ); pChNext++;
}
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
{
( void ) pxPort;
/* Place the character in the queue of characters to be transmitted. */
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
{
return pdFAIL;
}
/* Turn on the Tx interrupt so the ISR will remove the character from the
queue and send it. This does not need to be in a critical section as
if the interrupt has already removed the character the next interrupt
will simply turn off the Tx interrupt again. */
uart1->tx_mask = 1;
return pdPASS;
}
/*-----------------------------------------------------------*/
void vSerialClose( xComPortHandle xPort )
{
/* Not supported as not required by the demo application. */
( void ) xPort;
}
/*-----------------------------------------------------------*/
/* UART Tx interrupt handler. */
void interrupt5_handler( void )
{
/* This is a naked function. */
portSAVE_CONTEXT();
prvTxHandler();
portRESTORE_CONTEXT();
}
/*-----------------------------------------------------------*/
static void prvTxHandler( void )
{
signed char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* The interrupt was caused by the transmit fifo having space for at least one
character. Are there any more characters to transmit? */
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
{
/* A character was retrieved from the queue so can be sent to the uart now. */
uart1->tx_data = cChar;
}
else
{
/* Queue empty, nothing to send so turn off the Tx interrupt. */
uart1->tx_mask = 0;
}
/* If an event caused a task to unblock then we call "Yield from ISR" to
ensure that the unblocked task is the task that executes when the interrupt
completes if the unblocked task has a priority higher than the interrupted
task. */
portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
}
/*-----------------------------------------------------------*/
/* UART Rx interrupt. */
void interrupt6_handler( void )
{
portSAVE_CONTEXT();
prvRxHandler();
portRESTORE_CONTEXT();
}
/*-----------------------------------------------------------*/
static void prvRxHandler( void )
{
signed char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* The interrupt was caused by the receiver getting data. */
cChar = uart1->rx_data;
xQueueSendFromISR(xRxedChars, &cChar, &xHigherPriorityTaskWoken );
/* If an event caused a task to unblock then we call "Yield from ISR" to
ensure that the unblocked task is the task that executes when the interrupt
completes if the unblocked task has a priority higher than the interrupted
task. */
portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
}
/*-----------------------------------------------------------*/
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