6d87da4c59
- Add recursive_mutex
- Make all locking primitives and sleep use common overridable wait/notify support to allow RTOS
implementations to replace WFE/SEV with something more appropriate
- Add busy_wait_ms
89 lines
3.1 KiB
C
89 lines
3.1 KiB
C
/*
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* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#ifndef _PLATFORM_CRITICAL_SECTION_H
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#define _PLATFORM_CRITICAL_SECTION_H
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#include "pico/lock_core.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** \file critical_section.h
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* \defgroup critical_section critical_section
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* \ingroup pico_sync
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* \brief Critical Section API for short-lived mutual exclusion safe for IRQ and multi-core
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*
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* A critical section is non-reentrant, and provides mutual exclusion using a spin-lock to prevent access
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* from the other core, and from (higher priority) interrupts on the same core. It does the former
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* using a spin lock and the latter by disabling interrupts on the calling core.
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*
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* Because interrupts are disabled when a critical_section is owned, uses of the critical_section
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* should be as short as possible.
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*/
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typedef struct __packed_aligned critical_section {
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spin_lock_t *spin_lock;
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uint32_t save;
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} critical_section_t;
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/*! \brief Initialise a critical_section structure allowing the system to assign a spin lock number
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* \ingroup critical_section
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*
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* The critical section is initialized ready for use, and will use a (possibly shared) spin lock
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* number assigned by the system. Note that in general it is unlikely that you would be nesting
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* critical sections, however if you do so you *must* use \ref critical_section_init_with_lock_num
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* to ensure that the spin lock's used are different.
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*
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* \param crit_sec Pointer to critical_section structure
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*/
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void critical_section_init(critical_section_t *crit_sec);
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/*! \brief Initialise a critical_section structure assigning a specific spin lock number
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* \ingroup critical_section
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* \param crit_sec Pointer to critical_section structure
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* \param lock_num the specific spin lock number to use
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*/
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void critical_section_init_with_lock_num(critical_section_t *crit_sec, uint lock_num);
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/*! \brief Enter a critical_section
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* \ingroup critical_section
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*
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* If the spin lock associated with this critical section is in use, then this
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* method will block until it is released.
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*
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* \param crit_sec Pointer to critical_section structure
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*/
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static inline void critical_section_enter_blocking(critical_section_t *crit_sec) {
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crit_sec->save = spin_lock_blocking(crit_sec->spin_lock);
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}
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/*! \brief Release a critical_section
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* \ingroup critical_section
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*
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* \param crit_sec Pointer to critical_section structure
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*/
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static inline void critical_section_exit(critical_section_t *crit_sec) {
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spin_unlock(crit_sec->spin_lock, crit_sec->save);
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}
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/*! \brief De-Initialise a critical_section created by the critical_section_init method
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* \ingroup critical_section
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*
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* This method is only used to free the associated spin lock allocated via
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* the critical_section_init method (it should not be used to de-initialize a spin lock
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* created via critical_section_init_with_lock_num). After this call, the critical section is invalid
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*
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* \param crit_sec Pointer to critical_section structure
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*/
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void critical_section_deinit(critical_section_t *crit_sec);
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#ifdef __cplusplus
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}
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#endif
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#endif
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