wangchdo commented on code in PR #17675: URL: https://github.com/apache/nuttx/pull/17675#discussion_r2647738904
########## include/nuttx/hrtimer_queue.h: ########## @@ -0,0 +1,555 @@ +/**************************************************************************** + * include/nuttx/hrtimer_queue.h + * + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. + * + ****************************************************************************/ + +#ifndef __INCLUDE_HRTIMER_QUEUE_H +#define __INCLUDE_HRTIMER_QUEUE_H + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <nuttx/compiler.h> +#include <nuttx/clock.h> +#include <nuttx/seqlock.h> + +#include <nuttx/hrtimer_queue_type.h> + +#include <stdint.h> + +/* This header file should be only included for internal use, + * DO NOT EXPOSE IT TO USERS. + * + * Before including this file, Please provide the following inputs: + * + * Include the hrtimer_type_xxx.h header file. This header file should + * provide the implementation of the queue operations and definition for + * internal hrtimer. + * + * Function implementation: static inline_function + * void hrtimer_reprogram(FAR USER_HRTIMER_QUEUE_TYPE *queue, + * uint64_t next_expired); + * - Reprogram the timer hardware to the next expired time. + */ + +#ifdef __cplusplus +#define EXTERN extern "C" +extern "C" +{ +#else +#define EXTERN extern +#endif + +/**************************************************************************** + * Inline function + ****************************************************************************/ + +/* The relied function hrtimer_reprogram must be implemented. + * Please note the forward declaration and reverse dependency here. + * We instead of the function pointers because most functional-safety + * compilers (E.g. GHC, Tasking and CompCert C) do not support inlining + * function pointers, which would introduce additional memory and + * performance overhead. + */ + +static inline_function +void hrtimer_reprogram(FAR hrtimer_queue_internal_t *queue, + uint64_t next_expired); + +/* Reusable library code for user-defined high-resolution timer queue. */ + +/**************************************************************************** + * Name: hrtimer_queue_init + * + * Description: + * Initialize the hrtimer queue. + * + * Input Parameters: + * queue - The timer queue. + * guard_timer - The guard timer. + * + * Returned Value: + * 0 on OK, -EINVAL on error. + * + ****************************************************************************/ + +static inline_function +int hrtimer_queue_init(FAR hrtimer_queue_internal_t *queue) +{ + int ret = -EINVAL; + int cpu; + + if (queue) + { + FAR hrtimer_internal_t *guard_timer = &queue->guard_timer; + + /* The guard timer is designed to ensure the system will enter the + * safe state if the timing system is not working properly. + * It can be customized by the user after the hrtimer_queue_init + * and before the first user hrtimer is added. + * If the guard timer fired, it means 292-years have passed, which is + * impossible. In this case we should trigger the kernel panic and + * reboot the system. Here we assume the system will reboot after + * jumping to NULL. + */ + + hrtimer_fill(guard_timer, NULL, NULL, INT64_MAX); + + seqlock_init(&queue->lock); + + hrtimer_queue_clear(queue); + + queue->next_expired = UINT64_MAX; + hrtimer_queue_add(queue, guard_timer); + + memset(queue->running, 0, sizeof(queue->running)); + ret = OK; + } + + return ret; +} + +/**************************************************************************** + * Name: hrtimer_queue_read_64/32 + * + * Description: + * Internal function to read the value in the queue atomically. + * Do not use this function if you are not sure about the thread-safe + * of the value you are reading. + * + * Input Parameters: + * queue - The timer queue. + * ptr - The pointer to be read. + * + * Returned Value: + * The value in the queue. + * + ****************************************************************************/ + +static inline_function +uint64_t hrtimer_queue_read_64(FAR hrtimer_queue_internal_t *queue, + FAR const uint64_t *ptr) +{ + uint64_t val; + + DEBUGASSERT(queue && ptr); + +#ifdef CONFIG_ARCH_64BIT + /* On 64-bit architectures, read/write uint64_t is atomic. */ + + val = *((FAR volatile uint64_t *)ptr); +#else + uint32_t seq; + + do + { + seq = read_seqbegin(&queue->lock); + val = *ptr; + } + while (read_seqretry(&queue->lock, seq)); +#endif + + return val; +} + +static inline_function +uint32_t hrtimer_queue_read_32(FAR hrtimer_queue_internal_t *queue, + FAR const uint32_t *ptr) +{ + uint32_t val; + + DEBUGASSERT(queue && ptr); + +#if (UINT_MAX >= UINT32_MAX) + /* On 32/64-bit architectures, read/write uint32_t is atomic. */ + + val = *((FAR volatile uint32_t *)ptr); +#else + uint32_t seq; + + do + { + seq = read_seqbegin(&queue->lock); + val = *ptr; + } + while (read_seqretry(&queue->lock, seq)); +#endif + + return val; +} + +/* Generic function to read the value in the queue atomically. */ + +#define hrtimer_queue_read(queue, ptr) \ + (sizeof(*(ptr)) == 8u ? \ + hrtimer_queue_read_64(queue, (FAR const uint64_t *)(ptr)) : \ + (sizeof(*(ptr)) == 4u ? \ + hrtimer_queue_read_32(queue, (FAR const uint32_t *)(ptr)) : 0u)) + +/**************************************************************************** + * Name: hrtimer_queue_expiry + * + * Description: + * Process the time expiration of the hrtimer queue. + * + * Input Parameters: + * queue - The hrtimer queue. + * current - The current time. + * reprogram - The timer reprogram function. + * + * Returned Value: + * The next expiration time of the hrtimer queue. + * + * Assumption: + * The caller should be in the interrupt context. + * + ****************************************************************************/ + +static inline_function +uint64_t hrtimer_queue_expiry(FAR hrtimer_queue_internal_t *queue, + uint64_t current) +{ + FAR hrtimer_internal_t *timer; + FAR void *arg; + hrtimer_callback_t func; + uint64_t next_expired; + uint64_t expired; + int cpu = this_cpu(); + irqstate_t flags = write_seqlock_irqsave(&queue->lock); + + /* Check if we need processing the expiration. */ + + while (HRTIMER_TIME_BEFORE_EQ(queue->next_expired, current)) + { + timer = hrtimer_queue_peek(queue); + + /* Remove the hrtimer from the head of the queue + * and update the next_expired. + */ + + func = timer->func; + arg = timer->arg; + expired = timer->expired; + + /* Indicate the timer is not in the queue anymore. */ + + hrtimer_mark_dequeued(timer); + hrtimer_queue_del(queue, timer); + + /* Mark the hrtimer via the hazard potiner. In this case, + * User can not reclaim (deallocate or modify) the hrtimer. + */ + + queue->running[cpu] = (uintptr_t)timer; + + write_sequnlock_irqrestore(&queue->lock, flags); + + /* Execute the hrtimer function. */ + + next_expired = expired + func(arg, expired); + DEBUGASSERT(HRTIMER_TIME_AFTER_EQ(next_expired, expired)); + + flags = write_seqlock_irqsave(&queue->lock); + + /* In the interrupt context, the cpu core id should not change. + * NuttX currently does not support kernel preemption, thus interrupts + * cannot be nested within interrupt context. + * Even if kernel preemption and interrupt nesting are supported in the + * future, we can avoid nested calls to `hrtimer_expiry` by an + * interrupt nesting counter. + * Besides, in SMP mode, during interrupt handling, we use per-core + * `ARCH_INTERRUPTSTACK`, ensuring that the core ID remains unchanged + * while in interrupt context. + */ + + DEBUGASSERT(cpu == this_cpu()); + + /* If the hazard-pointer has not changed, we can re-enqueue the + * timer or release the ownership. Otherwise, the hrtimer should + * have been cancelled. In this case, we lose the ownership of the + * hrtimer and can not modify this hrtimer anymore. + */ + + if (queue->running[cpu] == timer) Review Comment: this logic is only SMP related, we should separate it with CONFIG_SMP to improve performance in non-smp target -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
