diff options
Diffstat (limited to 'apps/px4/tests/test_time.c')
| -rw-r--r-- | apps/px4/tests/test_time.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/apps/px4/tests/test_time.c b/apps/px4/tests/test_time.c new file mode 100644 index 000000000..c128c73a3 --- /dev/null +++ b/apps/px4/tests/test_time.c @@ -0,0 +1,160 @@ +/**************************************************************************** + * px4/tests/test_time.c + * + * Copyright (C) 2012 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. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <sys/types.h> + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <fcntl.h> +#include <errno.h> +#include <debug.h> + +#include <arch/board/board.h> + +#include "tests.h" + +#include <math.h> +#include <float.h> +#include <arch/board/up_hrt.h> + + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +/**************************************************************************** + * Public Data + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/* emulate hrt_absolute_time using the cycle counter */ +static hrt_abstime +cycletime(void) +{ + static uint64_t basetime; + static uint32_t lasttime; + uint32_t cycles; + + cycles = *(unsigned long *)0xe0001004; + + if (cycles < lasttime) + basetime += 0x100000000ULL; + + lasttime = cycles; + + return (basetime + cycles) / 168; +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: test_led + ****************************************************************************/ + +int test_time(int argc, char *argv[]) +{ + hrt_abstime h, c; + int64_t lowdelta, maxdelta = 0; + int64_t delta, deltadelta; + + /* enable the cycle counter */ + (*(unsigned long *)0xe000edfc) |= (1 << 24); /* DEMCR |= DEMCR_TRCENA */ + (*(unsigned long *)0xe0001000) |= 1; /* DWT_CTRL |= DWT_CYCCNT_ENA */ + + /* get an average delta between the two clocks - this should stay roughly the same */ + delta = 0; + + for (unsigned i = 0; i < 100; i++) { + uint32_t flags = irqsave(); + + h = hrt_absolute_time(); + c = cycletime(); + + irqrestore(flags); + + delta += h - c; + } + + lowdelta = abs(delta / 100); + + /* loop checking the time */ + for (unsigned i = 0; i < 100000; i++) { + + usleep(rand() * 10); + + uint32_t flags = irqsave(); + + c = cycletime(); + h = hrt_absolute_time(); + + irqrestore(flags); + + delta = abs(h - c); + deltadelta = abs(delta - lowdelta); + + if (deltadelta > maxdelta) + maxdelta = deltadelta; + + if (deltadelta > 1000) + fprintf(stderr, "h %llu c %llu d %lld\n", h, c, delta - lowdelta); + } + + printf("Maximum jitter %lld\n", maxdelta); + + return 0; +} |