lpc24xx/start/timer.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup RTEMSBSPsARMLPC24XX
0007  *
0008  * @brief Benchmark timer support.
0009  */
0010
0011 /*
0012  * Copyright (C) 2008, 2009 embedded brains GmbH & Co. KG
0013  *
0014  * Redistribution and use in source and binary forms, with or without
0015  * modification, are permitted provided that the following conditions
0016  * are met:
0017  * 1. Redistributions of source code must retain the above copyright
0018  *    notice, this list of conditions and the following disclaimer.
0019  * 2. Redistributions in binary form must reproduce the above copyright
0020  *    notice, this list of conditions and the following disclaimer in the
0021  *    documentation and/or other materials provided with the distribution.
0022  *
0023  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0024  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0025  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0026  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0027  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0028  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0029  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0032  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0033  * POSSIBILITY OF SUCH DAMAGE.
0034  */
0035
0036 #include <rtems.h>
0037 #include <bsp.h>
0038 #include <rtems/btimer.h>
0039
0040 #include <bsp/system-clocks.h>
0041
0042 bool benchmark_timer_find_average_overhead = false;
0043
0044 static uint32_t benchmark_timer_base;
0045
0046 void benchmark_timer_initialize(void)
0047 {
0048   benchmark_timer_base = lpc24xx_timer();
0049 }
0050
0051 benchmark_timer_t benchmark_timer_read(void)
0052 {
0053   uint32_t delta = lpc24xx_timer() - benchmark_timer_base;
0054
0055   if (benchmark_timer_find_average_overhead) {
0056     return delta;
0057   } else {
0058     /* Value determined by tmck for NCS board */
0059     if (delta > 74) {
0060       return delta - 74;
0061     } else {
0062       return 0;
0063     }
0064   }
0065 }
0066
0067 void benchmark_timer_disable_subtracting_average_overhead(bool find_average_overhead )
0068 {
0069   benchmark_timer_find_average_overhead = find_average_overhead;
0070 }