mirror of https://github.com/ArduPilot/ardupilot
158 lines
3.9 KiB
C
158 lines
3.9 KiB
C
/*
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* Copyright (C) Siddharth Bharat Purohit 2017
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* This file is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This file is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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High Resolution Timer code. This provides support for 32 and 64 bit
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returns for micros and millis functions
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*/
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#include "ch.h"
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#include "hal.h"
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#include "hrt.h"
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#include <stdint.h>
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#pragma GCC optimize("O2")
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#include "../../../AP_Math/div1000.h"
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/*
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we have 4 possible configurations of boards, made up of boards that
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have the following properties:
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CH_CFG_ST_RESOLUTION = 16 or 32
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CH_CFG_ST_FREQUENCY = 1000 or 1000000
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To keep as much code in common as possible we create a function
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system_time_u32_us() for all boards which gives system time since
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boot in microseconds, and which wraps at 0xFFFFFFFF.
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On top of this base function we build get_systime_us32() which has
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the same property, but which allows for a startup offset
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for micros64()
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*/
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#if CH_CFG_ST_RESOLUTION == 16
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static uint32_t system_time_u32_us(void)
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{
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systime_t now = chVTGetSystemTimeX();
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#if CH_CFG_ST_FREQUENCY != 1000000U
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#error "must use 32 bit timer if system clock not 1MHz"
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#endif
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static systime_t last_systime;
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static uint32_t timer_base_us32;
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uint16_t dt = now - last_systime;
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last_systime = now;
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timer_base_us32 += dt;
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return timer_base_us32;
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}
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#elif CH_CFG_ST_RESOLUTION == 32
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static uint32_t system_time_u32_us(void)
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{
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systime_t now = chVTGetSystemTimeX();
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#if CH_CFG_ST_FREQUENCY != 1000000U
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now *= 1000000U/CH_CFG_ST_FREQUENCY;
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#endif
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return now;
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}
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#else
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#error "unsupported timer resolution"
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#endif
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static uint32_t get_systime_us32(void)
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{
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uint32_t now = system_time_u32_us();
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#ifdef AP_BOARD_START_TIME
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now += AP_BOARD_START_TIME;
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#endif
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return now;
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}
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/*
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for the exposed functions we use chVTGetTimeStampI which handles
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wrap and directly gives a uint64_t (aka systimestamp_t)
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*/
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static uint64_t hrt_micros64I(void)
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{
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uint64_t ret = chVTGetTimeStampI();
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#if CH_CFG_ST_FREQUENCY != 1000000U
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ret *= 1000000U/CH_CFG_ST_FREQUENCY;
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#endif
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#ifdef AP_BOARD_START_TIME
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ret += AP_BOARD_START_TIME;
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#endif
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return ret;
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}
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static inline bool is_locked(void) {
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return !port_irq_enabled(port_get_irq_status());
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}
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uint64_t hrt_micros64()
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{
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if (is_locked()) {
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return hrt_micros64I();
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} else if (port_is_isr_context()) {
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uint64_t ret;
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chSysLockFromISR();
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ret = hrt_micros64I();
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chSysUnlockFromISR();
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return ret;
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} else {
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uint64_t ret;
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chSysLock();
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ret = hrt_micros64I();
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chSysUnlock();
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return ret;
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}
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}
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uint32_t hrt_micros32()
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{
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#if CH_CFG_ST_RESOLUTION == 16
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// boards with 16 bit timers need to call get_systime_us32() in a
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// lock state because on those boards we have local static
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// variables that need protection
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if (is_locked()) {
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return get_systime_us32();
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} else if (port_is_isr_context()) {
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uint32_t ret;
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chSysLockFromISR();
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ret = get_systime_us32();
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chSysUnlockFromISR();
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return ret;
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} else {
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uint32_t ret;
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chSysLock();
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ret = get_systime_us32();
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chSysUnlock();
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return ret;
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}
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#else
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return get_systime_us32();
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#endif
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}
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uint64_t hrt_millis64()
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{
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return uint64_div1000(hrt_micros64());
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}
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uint32_t hrt_millis32()
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{
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return (uint32_t)(hrt_millis64());
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}
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