230 lines
6.2 KiB
C
230 lines
6.2 KiB
C
/* system clock support for nanokernel-only systems */
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/*
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* Copyright (c) 1997-2015 Wind River Systems, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <nano_private.h>
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#include <toolchain.h>
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#include <sections.h>
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#include <wait_q.h>
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#include <drivers/system_timer.h>
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#ifdef CONFIG_SYS_CLOCK_EXISTS
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int sys_clock_us_per_tick = 1000000 / sys_clock_ticks_per_sec;
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int sys_clock_hw_cycles_per_tick =
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CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC / sys_clock_ticks_per_sec;
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#if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME)
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int sys_clock_hw_cycles_per_sec = CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC;
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#endif
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#else
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/* don't initialize to avoid division-by-zero error */
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int sys_clock_us_per_tick;
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int sys_clock_hw_cycles_per_tick;
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#if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME)
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int sys_clock_hw_cycles_per_sec;
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#endif
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#endif
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#ifdef CONFIG_NANOKERNEL
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/* updated by timer driver for tickless, stays at 1 for non-tickless */
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int32_t _sys_idle_elapsed_ticks = 1;
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#endif /* CONFIG_NANOKERNEL */
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int64_t _sys_clock_tick_count;
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/**
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*
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* @brief Return the lower part of the current system tick count
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*
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* @return the current system tick count
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*
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*/
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uint32_t sys_tick_get_32(void)
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{
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return (uint32_t)_sys_clock_tick_count;
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}
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/**
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*
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* @brief Return the current system tick count
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*
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* @return the current system tick count
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*
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*/
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int64_t sys_tick_get(void)
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{
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int64_t tmp_sys_clock_tick_count;
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/*
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* Lock the interrupts when reading _sys_clock_tick_count 64-bit variable.
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* Some architectures (x86) do not handle 64-bit atomically, so
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* we have to lock the timer interrupt that causes change of
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* _sys_clock_tick_count
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*/
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unsigned int imask = irq_lock();
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tmp_sys_clock_tick_count = _sys_clock_tick_count;
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irq_unlock(imask);
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return tmp_sys_clock_tick_count;
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}
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/**
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*
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* @brief Return number of ticks since a reference time
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*
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* This function is meant to be used in contained fragments of code. The first
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* call to it in a particular code fragment fills in a reference time variable
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* which then gets passed and updated every time the function is called. From
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* the second call on, the delta between the value passed to it and the current
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* tick count is the return value. Since the first call is meant to only fill in
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* the reference time, its return value should be discarded.
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*
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* Since a code fragment that wants to use sys_tick_delta() passes in its
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* own reference time variable, multiple code fragments can make use of this
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* function concurrently.
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*
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* e.g.
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* uint64_t reftime;
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* (void) sys_tick_delta(&reftime); /# prime it #/
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* [do stuff]
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* x = sys_tick_delta(&reftime); /# how long since priming #/
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* [do more stuff]
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* y = sys_tick_delta(&reftime); /# how long since [do stuff] #/
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*
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* @return tick count since reference time; undefined for first invocation
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*
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* NOTE: We use inline function for both 64-bit and 32-bit functions.
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* Compiler optimizes out 64-bit result handling in 32-bit version.
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*/
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static ALWAYS_INLINE int64_t _nano_tick_delta(int64_t *reftime)
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{
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int64_t delta;
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int64_t saved;
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/*
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* Lock the interrupts when reading _sys_clock_tick_count 64-bit variable.
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* Some architectures (x86) do not handle 64-bit atomically, so
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* we have to lock the timer interrupt that causes change of
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* _sys_clock_tick_count
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*/
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unsigned int imask = irq_lock();
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saved = _sys_clock_tick_count;
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irq_unlock(imask);
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delta = saved - (*reftime);
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*reftime = saved;
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return delta;
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}
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/**
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*
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* @brief Return number of ticks since a reference time
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*
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* @return tick count since reference time; undefined for first invocation
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*/
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int64_t sys_tick_delta(int64_t *reftime)
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{
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return _nano_tick_delta(reftime);
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}
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uint32_t sys_tick_delta_32(int64_t *reftime)
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{
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return (uint32_t)_nano_tick_delta(reftime);
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}
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/* handle the expired timeouts in the nano timeout queue */
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#ifdef CONFIG_NANO_TIMEOUTS
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#include <wait_q.h>
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static inline void handle_expired_nano_timeouts(int32_t ticks)
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{
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struct _nano_timeout *head =
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(struct _nano_timeout *)sys_dlist_peek_head(&_nanokernel.timeout_q);
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if (head) {
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head->delta_ticks_from_prev -= ticks;
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_nano_timeout_handle_timeouts();
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}
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}
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#else
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#define handle_expired_nano_timeouts(ticks) do { } while ((0))
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#endif
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/* handle the expired nano timers in the nano timers queue */
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#ifdef CONFIG_NANO_TIMERS
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#include <sys_clock.h>
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static inline void handle_expired_nano_timers(int ticks)
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{
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if (_nano_timer_list) {
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_nano_timer_list->ticks -= ticks;
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while (_nano_timer_list && (!_nano_timer_list->ticks)) {
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struct nano_timer *expired = _nano_timer_list;
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struct nano_lifo *lifo = &expired->lifo;
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_nano_timer_list = expired->link;
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nano_isr_lifo_put(lifo, expired->userData);
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}
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}
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}
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#else
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#define handle_expired_nano_timers(ticks) do { } while ((0))
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#endif
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/**
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*
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* @brief Announce a tick to the nanokernel
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*
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* This function is only to be called by the system clock timer driver when a
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* tick is to be announced to the nanokernel. It takes care of dequeuing the
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* timers that have expired and wake up the fibers pending on them.
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*
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* @return N/A
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*/
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void _nano_sys_clock_tick_announce(int32_t ticks)
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{
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_sys_clock_tick_count += ticks;
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handle_expired_nano_timeouts(ticks);
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handle_expired_nano_timers(ticks);
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}
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/* get closest nano timers deadline expiry, (uint32_t)TICKS_UNLIMITED if none */
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#ifdef CONFIG_NANO_TIMERS
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static inline uint32_t _nano_get_earliest_timers_deadline(void)
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{
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return _nano_timer_list ? _nano_timer_list->ticks : TICKS_UNLIMITED;
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}
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#else
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static inline uint32_t _nano_get_earliest_timers_deadline(void)
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{
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return TICKS_UNLIMITED;
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}
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#endif
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/*
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* Get closest nano timeouts/timers deadline expiry, (uint32_t)TICKS_UNLIMITED
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* if none.
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*/
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uint32_t _nano_get_earliest_deadline(void)
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{
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return min(_nano_get_earliest_timeouts_deadline(),
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_nano_get_earliest_timers_deadline());
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}
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