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160 lines
4.9 KiB
160 lines
4.9 KiB
/**************************************************************************** |
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* px4/tests/test_time.c |
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* |
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* Copyright (C) 2012 PX4 Development Team. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name PX4 nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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* |
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****************************************************************************/ |
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/**************************************************************************** |
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* Included Files |
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****************************************************************************/ |
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#include <nuttx/config.h> |
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#include <sys/types.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <unistd.h> |
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#include <fcntl.h> |
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#include <errno.h> |
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#include <debug.h> |
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#include <arch/board/board.h> |
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#include "tests.h" |
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#include <math.h> |
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#include <float.h> |
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#include <drivers/drv_hrt.h> |
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/**************************************************************************** |
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* Pre-processor Definitions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Types |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Function Prototypes |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Data |
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****************************************************************************/ |
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/**************************************************************************** |
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* Public Data |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Functions |
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****************************************************************************/ |
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/* emulate hrt_absolute_time using the cycle counter */ |
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static hrt_abstime |
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cycletime(void) |
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{ |
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static uint64_t basetime; |
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static uint32_t lasttime; |
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uint32_t cycles; |
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cycles = *(unsigned long *)0xe0001004; |
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if (cycles < lasttime) |
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basetime += 0x100000000ULL; |
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lasttime = cycles; |
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return (basetime + cycles) / 168; /* XXX magic number */ |
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} |
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/**************************************************************************** |
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* Public Functions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Name: test_led |
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****************************************************************************/ |
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int test_time(int argc, char *argv[]) |
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{ |
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hrt_abstime h, c; |
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int64_t lowdelta, maxdelta = 0; |
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int64_t delta, deltadelta; |
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/* enable the cycle counter */ |
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(*(unsigned long *)0xe000edfc) |= (1 << 24); /* DEMCR |= DEMCR_TRCENA */ |
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(*(unsigned long *)0xe0001000) |= 1; /* DWT_CTRL |= DWT_CYCCNT_ENA */ |
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/* get an average delta between the two clocks - this should stay roughly the same */ |
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delta = 0; |
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for (unsigned i = 0; i < 100; i++) { |
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uint32_t flags = irqsave(); |
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h = hrt_absolute_time(); |
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c = cycletime(); |
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irqrestore(flags); |
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delta += h - c; |
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} |
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lowdelta = abs(delta / 100); |
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/* loop checking the time */ |
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for (unsigned i = 0; i < 100; i++) { |
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usleep(rand()); |
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uint32_t flags = irqsave(); |
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c = cycletime(); |
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h = hrt_absolute_time(); |
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irqrestore(flags); |
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delta = abs(h - c); |
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deltadelta = abs(delta - lowdelta); |
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if (deltadelta > maxdelta) |
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maxdelta = deltadelta; |
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if (deltadelta > 1000) |
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fprintf(stderr, "h %llu c %llu d %lld\n", h, c, delta - lowdelta); |
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} |
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printf("Maximum jitter %lldus\n", maxdelta); |
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return 0; |
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}
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