blob: 0cb6bdb249f47056772e778e532f68828718a336 [file] [log] [blame]
/*
* Copyright (c) 1997-2015, Wind River Systems, Inc.
* Copyright (c) 2021 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef ZEPHYR_INCLUDE_SYS_ATOMIC_H_
#define ZEPHYR_INCLUDE_SYS_ATOMIC_H_
#include <stdbool.h>
#include <toolchain.h>
#include <stddef.h>
#include <zephyr/types.h>
#include <sys/util_macro.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef long atomic_t;
typedef atomic_t atomic_val_t;
typedef void *atomic_ptr_t;
typedef atomic_ptr_t atomic_ptr_val_t;
/* Low-level primitives come in several styles: */
#if defined(CONFIG_ATOMIC_OPERATIONS_C)
/* Generic-but-slow implementation based on kernel locking and syscalls */
#include <sys/atomic_c.h>
#elif defined(CONFIG_ATOMIC_OPERATIONS_ARCH)
/* Some architectures need their own implementation */
# ifdef CONFIG_XTENSA
/* Not all Xtensa toolchains support GCC-style atomic intrinsics */
# include <arch/xtensa/atomic_xtensa.h>
# else
/* Other arch specific implementation */
# include <sys/atomic_arch.h>
# endif /* CONFIG_XTENSA */
#else
/* Default. See this file for the Doxygen reference: */
#include <sys/atomic_builtin.h>
#endif
/* Portable higher-level utilities: */
/**
* @defgroup atomic_apis Atomic Services APIs
* @ingroup kernel_apis
* @{
*/
/**
* @brief Initialize an atomic variable.
*
* This macro can be used to initialize an atomic variable. For example,
* @code atomic_t my_var = ATOMIC_INIT(75); @endcode
*
* @param i Value to assign to atomic variable.
*/
#define ATOMIC_INIT(i) (i)
/**
* @brief Initialize an atomic pointer variable.
*
* This macro can be used to initialize an atomic pointer variable. For
* example,
* @code atomic_ptr_t my_ptr = ATOMIC_PTR_INIT(&data); @endcode
*
* @param p Pointer value to assign to atomic pointer variable.
*/
#define ATOMIC_PTR_INIT(p) (p)
/**
* @cond INTERNAL_HIDDEN
*/
#define ATOMIC_BITS (sizeof(atomic_val_t) * 8)
#define ATOMIC_MASK(bit) BIT((unsigned long)(bit) & (ATOMIC_BITS - 1U))
#define ATOMIC_ELEM(addr, bit) ((addr) + ((bit) / ATOMIC_BITS))
/**
* INTERNAL_HIDDEN @endcond
*/
/**
* @brief This macro computes the number of atomic variables necessary to
* represent a bitmap with @a num_bits.
*
* @param num_bits Number of bits.
*/
#define ATOMIC_BITMAP_SIZE(num_bits) (1 + ((num_bits) - 1) / ATOMIC_BITS)
/**
* @brief Define an array of atomic variables.
*
* This macro defines an array of atomic variables containing at least
* @a num_bits bits.
*
* @note
* If used from file scope, the bits of the array are initialized to zero;
* if used from within a function, the bits are left uninitialized.
*
* @cond INTERNAL_HIDDEN
* @note
* This macro should be replicated in the PREDEFINED field of the documentation
* Doxyfile.
* @endcond
*
* @param name Name of array of atomic variables.
* @param num_bits Number of bits needed.
*/
#define ATOMIC_DEFINE(name, num_bits) \
atomic_t name[ATOMIC_BITMAP_SIZE(num_bits)]
/**
* @brief Atomically test a bit.
*
* This routine tests whether bit number @a bit of @a target is set or not.
* The target may be a single atomic variable or an array of them.
*
* @note As for all atomic APIs, includes a
* full/sequentially-consistent memory barrier (where applicable).
*
* @param target Address of atomic variable or array.
* @param bit Bit number (starting from 0).
*
* @return true if the bit was set, false if it wasn't.
*/
static inline bool atomic_test_bit(const atomic_t *target, int bit)
{
atomic_val_t val = atomic_get(ATOMIC_ELEM(target, bit));
return (1 & (val >> (bit & (ATOMIC_BITS - 1)))) != 0;
}
/**
* @brief Atomically test and clear a bit.
*
* Atomically clear bit number @a bit of @a target and return its old value.
* The target may be a single atomic variable or an array of them.
*
* @note As for all atomic APIs, includes a
* full/sequentially-consistent memory barrier (where applicable).
*
* @param target Address of atomic variable or array.
* @param bit Bit number (starting from 0).
*
* @return true if the bit was set, false if it wasn't.
*/
static inline bool atomic_test_and_clear_bit(atomic_t *target, int bit)
{
atomic_val_t mask = ATOMIC_MASK(bit);
atomic_val_t old;
old = atomic_and(ATOMIC_ELEM(target, bit), ~mask);
return (old & mask) != 0;
}
/**
* @brief Atomically set a bit.
*
* Atomically set bit number @a bit of @a target and return its old value.
* The target may be a single atomic variable or an array of them.
*
* @note As for all atomic APIs, includes a
* full/sequentially-consistent memory barrier (where applicable).
*
* @param target Address of atomic variable or array.
* @param bit Bit number (starting from 0).
*
* @return true if the bit was set, false if it wasn't.
*/
static inline bool atomic_test_and_set_bit(atomic_t *target, int bit)
{
atomic_val_t mask = ATOMIC_MASK(bit);
atomic_val_t old;
old = atomic_or(ATOMIC_ELEM(target, bit), mask);
return (old & mask) != 0;
}
/**
* @brief Atomically clear a bit.
*
* Atomically clear bit number @a bit of @a target.
* The target may be a single atomic variable or an array of them.
*
* @note As for all atomic APIs, includes a
* full/sequentially-consistent memory barrier (where applicable).
*
* @param target Address of atomic variable or array.
* @param bit Bit number (starting from 0).
*/
static inline void atomic_clear_bit(atomic_t *target, int bit)
{
atomic_val_t mask = ATOMIC_MASK(bit);
(void)atomic_and(ATOMIC_ELEM(target, bit), ~mask);
}
/**
* @brief Atomically set a bit.
*
* Atomically set bit number @a bit of @a target.
* The target may be a single atomic variable or an array of them.
*
* @note As for all atomic APIs, includes a
* full/sequentially-consistent memory barrier (where applicable).
*
* @param target Address of atomic variable or array.
* @param bit Bit number (starting from 0).
*/
static inline void atomic_set_bit(atomic_t *target, int bit)
{
atomic_val_t mask = ATOMIC_MASK(bit);
(void)atomic_or(ATOMIC_ELEM(target, bit), mask);
}
/**
* @brief Atomically set a bit to a given value.
*
* Atomically set bit number @a bit of @a target to value @a val.
* The target may be a single atomic variable or an array of them.
*
* @note As for all atomic APIs, includes a
* full/sequentially-consistent memory barrier (where applicable).
*
* @param target Address of atomic variable or array.
* @param bit Bit number (starting from 0).
* @param val true for 1, false for 0.
*/
static inline void atomic_set_bit_to(atomic_t *target, int bit, bool val)
{
atomic_val_t mask = ATOMIC_MASK(bit);
if (val) {
(void)atomic_or(ATOMIC_ELEM(target, bit), mask);
} else {
(void)atomic_and(ATOMIC_ELEM(target, bit), ~mask);
}
}
/**
* @}
*/
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* ZEPHYR_INCLUDE_SYS_ATOMIC_H_ */