esp-idf/components/esp_system/include/esp_private/critical_section.h

384 lines
14 KiB
C

/*
* SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* This file provides an abstract OS API for entering and exiting critical sections.
* It furthermore provides macros to define and initialize an optional spinlock
* if the used chip is a multi-core chip. If a single-core chip is used, just disabling interrupts
* is sufficient to guarantee consecutive, non-interrupted execution of a critical section.
* Hence, the spinlock is unneccessary and will be automatically ommitted by the macros.
*/
#pragma once
#include "freertos/portmacro.h"
#include "spinlock.h"
#ifdef __cplusplus
extern "C" {
#endif
#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S3 || CONFIG_IDF_TARGET_ESP32S2
/**
* This macro also helps users switching between spinlock declarations/definitions for multi-/single core environments
* if the macros below aren't sufficient.
*/
#define OS_SPINLOCK 1
#else
#define OS_SPINLOCK 0
#endif
#if OS_SPINLOCK == 1
typedef spinlock_t esp_os_spinlock_t;
#endif
/**
* Define and initialize a static (internal linking) lock for entering critical sections.
*
* Use this when all the critical sections are local inside a file.
* The lock will only be defined if built for a multi-core system, otherwise it is unnecessary.
*
* @note When using this macro, the critical section macros esp_os_enter_critical* and esp_os_exit_critical*
* MUST be used, otherwise normal functions would be passed an undefined variable when build for single-core systems.
*
* @param lock_name Variable name of the lock. This will later be used to reference the declared lock.
* @param optional_qualifiers Qualifiers such as DRAM_ATTR and other attributes. Can be omitted if no qualifiers are
* required.
*
* Example usage:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* DEFINE_CRIT_SECTION_LOCK_STATIC(my_lock); // will have internal linking (static)
* ...
* esp_os_enter_critical(&my_lock);
* ...
* esp_os_exit_critical(&my_lock);
* @endcode
*/
#if OS_SPINLOCK == 1
#define DEFINE_CRIT_SECTION_LOCK_STATIC(lock_name, optional_qualifiers...) static optional_qualifiers esp_os_spinlock_t lock_name = SPINLOCK_INITIALIZER
#else
#define DEFINE_CRIT_SECTION_LOCK_STATIC(lock_name, optional_qualifiers...)
#endif
/**
* Define and initialize a non-static (external linking) lock for entering critical sections.
*
* Locks defined by this macro can be linked among object files but this rather exceptional.
* Prefer the static lock definition whenever possible.
* The lock will only be defined if built for a multi-core system, otherwise it is unnecessary.
*
* @note When using this macro, the critical section macros esp_os_enter_critical* and esp_os_exit_critical*
* MUST be used, otherwise normal functions would be passed an undefined variable when build for single-core systems.
*
* @param lock_name Variable name of the lock. This will later be used to reference the declared lock.
* @param optional_qualifiers Qualifiers such as DRAM_ATTR and other attributes. Can be omitted if no qualifiers are
* required.
*
* Example usage:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* DEFINE_CRIT_SECTION_LOCK(my_lock); // will have external linking (non-static)
* ...
* esp_os_enter_critical(&my_lock);
* ...
* esp_os_exit_critical(&my_lock);
* @endcode
*/
#if OS_SPINLOCK == 1
#define DEFINE_CRIT_SECTION_LOCK(lock_name, optional_qualifiers...) optional_qualifiers esp_os_spinlock_t lock_name = SPINLOCK_INITIALIZER
#else
#define DEFINE_CRIT_SECTION_LOCK(lock_name, optional_qualifiers...)
#endif
/**
* @brief This macro initializes a critical section lock at runtime.
*
* This macro basically creates a member of the initialization list, including the trailing comma.
* If the lock is unnecessary because the architecture is single-core, this macro will not do anything.
* This is incompatible with a lock created by DEFINE_CRIT_SECTION_LOCK_STATIC from above.
*
* @param lock_name Pointer to the lock.
*
* @note When using this macro, the critical section macros esp_os_enter_critical* and esp_os_exit_critical*
* MUST be used, otherwise normal functions would be passed an undefined variable when build for single-core
* systems.
*
* Example usage:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* typedef struct protected_struct_t {
* int member1;
* DECLARE_CRIT_SECTION_LOCK_IN_STRUCT(my_lock)
* int another_member;
* };
* ...
* protected_struct_t my_protected;
* INIT_CRIT_SECTION_LOCK_IN_STRUCT(&(my_protected.my_lock));
* };
* @endcode
*/
#if OS_SPINLOCK == 1
#define INIT_CRIT_SECTION_LOCK_RUNTIME(lock_name) spinlock_initialize(lock_name)
#else
#define INIT_CRIT_SECTION_LOCK_RUNTIME(lock_name)
#endif
/**
* @brief This macro declares a critical section lock as a member of a struct.
*
* The critical section lock member is only declared if built for multi-core systems, otherwise it is omitted.
*
* @note When using this macro, the critical section macros esp_os_enter_critical* and esp_os_exit_critical*
* MUST be used, otherwise normal functions would be passed an undefined variable when build for single-core
* systems.
* @note Do NOT add any semicolon after declaring the member with this macro.
* The trailing semicolon is included in the macro, otherwise -Wpedantic would complain about
* superfluous ";" if OS_SPINLOCK == 0.
*
* Example usage:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* typedef struct protected_struct_t {
* int member1;
* DECLARE_CRIT_SECTION_LOCK_IN_STRUCT(my_lock) // no semicolon!
* int another_member;
* };
* @endcode
*/
#if OS_SPINLOCK == 1
#define DECLARE_CRIT_SECTION_LOCK_IN_STRUCT(lock_name) esp_os_spinlock_t lock_name;
#else
#define DECLARE_CRIT_SECTION_LOCK_IN_STRUCT(lock_name)
#endif
/**
* @brief This macro initializes a critical section lock as a member of a struct when using an list initialization.
* It has to be used together with \c DECLARE_CRIT_SECTION_LOCK_IN_STRUCT() to work.
*
* This macro basically creates a member of the initialization list, including the trailing comma.
* If the lock is unnecessary because the architecture is single-core, this macro will not do anything.
* This means that if \c lock_name is still a member of the struct, \c lock_name will be uninitialized.
* Hence, this macro has to be used together with \c DECLARE_CRIT_SECTION_LOCK_IN_STRUCT() to correctly to declare
* or omit the struct member \c lock_name.
*
* @param lock_name The field name of the lock inside the struct.
*
* @note When using this macro, the critical section macros esp_os_enter_critical* and esp_os_exit_critical*
* MUST be used, otherwise normal functions would be passed an undefined variable when build for single-core
* systems.
* @note Do NOT add any comma in the initializer list after using this macro.
*
* Example usage:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* typedef struct protected_struct_t {
* int member1;
* DECLARE_CRIT_SECTION_LOCK_IN_STRUCT(my_lock)
* int another_member;
* };
* ...
* protected_struct_t my_protected = {
* .member1 = 0,
* INIT_CRIT_SECTION_LOCK_IN_STRUCT(my_lock) // no comma!
* another_member = 47,
* };
* @endcode
*/
#if OS_SPINLOCK == 1
#define INIT_CRIT_SECTION_LOCK_IN_STRUCT(lock_name) .lock_name = portMUX_INITIALIZER_UNLOCKED,
#else
#define INIT_CRIT_SECTION_LOCK_IN_STRUCT(lock_name)
#endif
/**
* @brief Enter a critical section, i.e., a section that will not be interrupted by any other task or interrupt.
*
* On multi-core systems, this will disable interrupts and take the spinlock \c lock. On single core systems, a
* spinlock is unncessary, hence \c lock is ignored and interrupts are disabled only.
*
* @note This macro MUST be used together with any of the initialization macros, e.g.
* DEFINE_CRIT_SECTION_LOCK_STATIC. If not, there may be unused variables.
*
* @param lock Pointer to the critical section lock. Ignored if build for single core system.
*
* Example usage with static locks:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* DEFINE_CRIT_SECTION_LOCK_STATIC(my_lock); // will have internal linking (static)
* ...
* esp_os_enter_critical(&my_lock);
* // code inside critical section
* esp_os_exit_critical(&my_lock);
* @endcode
*/
#if OS_SPINLOCK == 1
#define esp_os_enter_critical(lock) portENTER_CRITICAL(lock)
#else
#define esp_os_enter_critical(lock) vPortEnterCritical()
#endif
/**
* @brief Exit a critical section.
*
* On multi-core systems, this will enable interrupts and release the spinlock \c lock. On single core systems, a
* spinlock is unncessary, hence \c lock is ignored and interrupts are enabled only.
*
* @note This macro MUST be used together with any of the initialization macros, e.g.
* DEFINE_CRIT_SECTION_LOCK_STATIC. If not, there may be unused variables.
*
* @param lock Pointer to the critical section lock. Ignored if build for single core system.
*
* Example usage with static locks:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* DEFINE_CRIT_SECTION_LOCK_STATIC(my_lock); // will have internal linking (static)
* ...
* esp_os_enter_critical(&my_lock);
* // code inside critical section
* esp_os_exit_critical(&my_lock);
* @endcode
*/
#if OS_SPINLOCK == 1
#define esp_os_exit_critical(lock) portEXIT_CRITICAL(lock)
#else
#define esp_os_exit_critical(lock) vPortExitCritical()
#endif
/**
* @brief Enter a critical section while from ISR.
*
* On multi-core systems, this will disable interrupts and take the spinlock \c lock. On single core systems, a
* spinlock is unncessary, hence \c lock is ignored and interrupts are disabled only.
*
* @note This macro MUST be used together with any of the initialization macros, e.g.
* DEFINE_CRIT_SECTION_LOCK_STATIC. If not, there may be unused variables.
*
* @param lock Pointer to the critical section lock. Ignored if build for single core system.
*
* Example usage with static locks:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* DEFINE_CRIT_SECTION_LOCK_STATIC(my_lock); // will have internal linking (static)
* ...
* esp_os_enter_critical(&my_lock);
* // code inside critical section
* esp_os_exit_critical(&my_lock);
* @endcode
*/
#if OS_SPINLOCK == 1
#define esp_os_enter_critical_isr(lock) portENTER_CRITICAL_ISR(lock)
#else
#define esp_os_enter_critical_isr(lock) vPortEnterCritical()
#endif
/**
* @brief Exit a critical section after entering from ISR.
*
* On multi-core systems, this will enable interrupts and release the spinlock \c lock. On single core systems, a
* spinlock is unncessary, hence \c lock is ignored and interrupts are enabled only.
*
* @note This macro MUST be used together with any of the initialization macros, e.g.
* DEFINE_CRIT_SECTION_LOCK_STATIC. If not, there may be unused variables.
*
* @param lock Pointer to the critical section lock. Ignored if build for single core system.
*
* Example usage with static locks:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* DEFINE_CRIT_SECTION_LOCK_STATIC(my_lock); // will have internal linking (static)
* ...
* esp_os_enter_critical(&my_lock);
* // code inside critical section
* esp_os_exit_critical(&my_lock);
* @endcode
*/
#if OS_SPINLOCK == 1
#define esp_os_exit_critical_isr(lock) portEXIT_CRITICAL_ISR(lock)
#else
#define esp_os_exit_critical_isr(lock) vPortExitCritical()
#endif
/**
* @brief Enter a critical section from normal task or ISR. This macro will check if the current CPU is processing
* an ISR or not and enter the critical section accordingly.
*
* On multi-core systems, this will disable interrupts and take the spinlock \c lock. On single core systems, a
* spinlock is unncessary, hence \c lock is ignored and interrupts are disabled only.
*
* @note This macro MUST be used together with any of the initialization macros, e.g.
* DEFINE_CRIT_SECTION_LOCK_STATIC. If not, there may be unused variables.
*
* @param lock Pointer to the critical section lock. Ignored if build for single core system.
*
* Example usage with static locks:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* DEFINE_CRIT_SECTION_LOCK_STATIC(my_lock); // will have internal linking (static)
* ...
* esp_os_enter_critical(&my_lock);
* // code inside critical section
* esp_os_exit_critical(&my_lock);
* @endcode
*/
#if OS_SPINLOCK == 1
#define esp_os_enter_critical_safe(lock) portENTER_CRITICAL_SAFE(lock)
#else
#define esp_os_enter_critical_safe(lock) vPortEnterCritical()
#endif
/**
* @brief Exit a critical section after entering via esp_os_enter_critical_safe.
*
* On multi-core systems, this will enable interrupts and release the spinlock \c lock. On single core systems, a
* spinlock is unncessary, hence \c lock is ignored and interrupts are enabled only.
*
* @note This macro MUST be used together with any of the initialization macros, e.g.
* DEFINE_CRIT_SECTION_LOCK_STATIC. If not, there may be unused variables.
*
* @param lock Pointer to the critical section lock. Ignored if build for single core system.
*
* Example usage with static locks:
* @code{c}
* ...
* #include "os/critical_section.h"
* ...
* DEFINE_CRIT_SECTION_LOCK_STATIC(my_lock); // will have internal linking (static)
* ...
* esp_os_enter_critical(&my_lock);
* // code inside critical section
* esp_os_exit_critical(&my_lock);
* @endcode
*/
#if OS_SPINLOCK == 1
#define esp_os_exit_critical_safe(lock) portEXIT_CRITICAL_SAFE(lock)
#else
#define esp_os_exit_critical_safe(lock) vPortExitCritical()
#endif
#ifdef __cplusplus
}
#endif