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/* nano_int_to_fiber.c - measure switching time from ISR back to fiber */
/*
* Copyright (c) 2012-2014 Wind River Systems, Inc.
*
* 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 of Wind River Systems 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 HOLDER 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.
*/
/*
* DESCRIPTION
* This file contains test that measures the switching time from the
* interrupt handler back to the executing fiber that got interrupted.
*/
#include "timestamp.h"
#include "utils.h"
#include <nanokernel/cpu.h>
#define STACKSIZE 2000
/* stack used by the fiber that generates the interrupt */
static char fiberStack[STACKSIZE];
static volatile int flagVar = 0;
static uint32_t timestamp;
/*******************************************************************************
*
* latencyTestIsr - test ISR used to measure best case interrupt latency
*
* The interrupt handler gets the second timestamp.
*
* RETURNS: N/A
*
* \NOMANUAL
*/
static void latencyTestIsr(void *unused)
{
ARG_UNUSED(unused);
flagVar = 1;
timestamp = TIME_STAMP_DELTA_GET(0);
}
/*******************************************************************************
*
* fiberInt - interrupt preparation fiber
*
* Fiber makes all the test preparations: registers the interrupt handler,
* gets the first timestamp and invokes the software interrupt.
*
* RETURNS: N/A
*
* \NOMANUAL
*/
static void fiberInt(void)
{
setSwInterrupt(latencyTestIsr);
flagVar = 0;
raiseIntFunc();
if (flagVar != 1) {
PRINT_FORMAT(" Flag variable has not changed. FAILED");
}
else
timestamp = TIME_STAMP_DELTA_GET(timestamp);
}
/*******************************************************************************
*
* nanoIntToFiber - the test main function
*
* RETURNS: 0 on success
*
* \NOMANUAL
*/
int nanoIntToFiber(void)
{
PRINT_FORMAT(" 2- Measure time to switch from ISR back to interrupted"
" fiber");
TICK_SYNCH();
task_fiber_start(&fiberStack[0], STACKSIZE,
(nano_fiber_entry_t) fiberInt, 0, 0, 6, 0);
if (flagVar == 1) {
PRINT_FORMAT(" switching time is %lu tcs = %lu nsec",
timestamp, SYS_CLOCK_HW_CYCLES_TO_NS(timestamp));
}
return 0;
}
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