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wangchengdong
ed1cb6f9b8
NuttX provides the wdog module to implement timers for the scheduler. While it is lightweight and efficient, wdog only supports tick-level timers, typically in milliseconds. Although the tick duration can be configured, setting it to microsecond or nanosecond resolution is not practical. Doing so may cause an interrupt storm, where the CPU is constantly occupied handling tick interrupts. To address this limitation, a new hrtimer module is introduced. It coexists with the wdog module, providing both tick-level timers for wdog and high-resolution timers (nanosecond-level) directly to users. Signed-off-by: Chengdong Wang <wangchengdong@lixiang.com>
80 lines
3.1 KiB
C
80 lines
3.1 KiB
C
/****************************************************************************
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* sched/hrtimer/hrtimer_initialize.c
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. 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, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 "hrtimer/hrtimer.h"
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/****************************************************************************
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* Public Data
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****************************************************************************/
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/* Global spinlock protecting the high-resolution timer subsystem.
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*
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* This spinlock serializes access to the hrtimer red-black tree and
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* protects timer state transitions. It must be held whenever the
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* timer tree or hrtimer state is modified.
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*/
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spinlock_t g_hrtimer_spinlock = SP_UNLOCKED;
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/* Red-black tree containing all active high-resolution timers.
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*
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* Only timers in the ARMED state are present in this tree. Timers in
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* the RUNNING, CANCELED, or INACTIVE states must not be inserted.
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*
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* The tree is ordered by absolute expiration time.
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*/
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struct hrtimer_tree_s g_hrtimer_tree =
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RB_INITIALIZER(g_hrtimer_tree);
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: RB_GENERATE
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*
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* Description:
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* Instantiate the red-black tree helper functions for the hrtimer
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* subsystem.
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*
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* This macro generates the static inline functions required to
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* manipulate the hrtimer red-black tree, including insertion,
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* removal, and lookup operations.
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*
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* Assumptions/Notes:
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* - The tree key is the absolute expiration time stored in
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* hrtimer_node_s and compared via hrtimer_compare().
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* - All accesses to the tree must be serialized using
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* g_hrtimer_spinlock.
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* - These generated functions are used internally by the hrtimer
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* core (e.g., hrtimer_start(), hrtimer_cancel(), and expire paths).
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****************************************************************************/
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RB_GENERATE(hrtimer_tree_s, hrtimer_node_s, entry, hrtimer_compare);
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