init.h

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/*
 * Copyright (c) 2015 Intel Corporation.
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
#ifndef ZEPHYR_INCLUDE_INIT_H_
#define ZEPHYR_INCLUDE_INIT_H_
 
#include <stdint.h>
#include <stddef.h>
 
#include <zephyr/sys/util.h>
#include <zephyr/toolchain.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
struct device;
 
union init_function {
        int (*sys)(void);
        int (*dev)(const struct device *dev);
#ifdef CONFIG_DEVICE_MUTABLE
        int (*dev_rw)(struct device *dev);
#endif
};
 
struct init_entry {
        union init_function init_fn;
        union {
                const struct device *dev;
#ifdef CONFIG_DEVICE_MUTABLE
                struct device *dev_rw;
#endif
        };
};
 
/* Helper definitions to evaluate level equality */
#define Z_INIT_EARLY_EARLY               1
#define Z_INIT_PRE_KERNEL_1_PRE_KERNEL_1 1
#define Z_INIT_PRE_KERNEL_2_PRE_KERNEL_2 1
#define Z_INIT_POST_KERNEL_POST_KERNEL   1
#define Z_INIT_APPLICATION_APPLICATION   1
#define Z_INIT_SMP_SMP                   1
 
/* Init level ordinals */
#define Z_INIT_ORD_EARLY        0
#define Z_INIT_ORD_PRE_KERNEL_1 1
#define Z_INIT_ORD_PRE_KERNEL_2 2
#define Z_INIT_ORD_POST_KERNEL  3
#define Z_INIT_ORD_APPLICATION  4
#define Z_INIT_ORD_SMP          5
 
#define Z_INIT_ENTRY_NAME(init_id) _CONCAT(__init_, init_id)
 
#define Z_INIT_ENTRY_SECTION(level, prio, sub_prio)                           \
        __attribute__((__section__(                                           \
                ".z_init_" #level STRINGIFY(prio)"_" STRINGIFY(sub_prio)"_")))
 
 
/* Designated initializers where added to C in C99. There were added to
 * C++ 20 years later in a much more restricted form. C99 allows many
 * variations: out of order, mix of designated and not, overlap,
 * override,... but C++ allows none of these. See differences detailed
 * in the P0329R0.pdf C++ proposal.
 * Note __STDC_VERSION__ is undefined when compiling C++.
 */
#if defined(__STDC_VERSION__) && (__STDC_VERSION__) < 201100
 
/* Anonymous unions require C11. Some pre-C11 gcc versions have early
 * support for anonymous unions but they require these braces when
 * combined with C99 designated initializers, see longer discussion in
 * #69411.
 * These braces are compatible with any C version but not with C++20.
 */
#  define Z_INIT_SYS_INIT_DEV_NULL  { .dev = NULL }
 
#else
 
/* When using -std=c++20 or higher, g++ (v12.2.0) reject braces for
 * initializing anonymous unions because it is technically a mix of
 * designated and not designated initializers which is not allowed in
 * C++. Interestingly, the _same_ g++ version does accept the braces above
 * when using -std=c++17 or lower!
 * The tests/lib/cpp/cxx/ added by commit 3d9c428d57bf invoke the C++
 * compiler with a range of different `-std=...` parameters without needing
 * any manual configuration.
 */
#  define Z_INIT_SYS_INIT_DEV_NULL    .dev = NULL
 
#endif
 
#define INIT_LEVEL_ORD(level)                                                  \
        COND_CODE_1(Z_INIT_EARLY_##level, (Z_INIT_ORD_EARLY),                  \
        (COND_CODE_1(Z_INIT_PRE_KERNEL_1_##level, (Z_INIT_ORD_PRE_KERNEL_1),   \
        (COND_CODE_1(Z_INIT_PRE_KERNEL_2_##level, (Z_INIT_ORD_PRE_KERNEL_2),   \
        (COND_CODE_1(Z_INIT_POST_KERNEL_##level, (Z_INIT_ORD_POST_KERNEL),     \
        (COND_CODE_1(Z_INIT_APPLICATION_##level, (Z_INIT_ORD_APPLICATION),     \
        (COND_CODE_1(Z_INIT_SMP_##level, (Z_INIT_ORD_SMP),                     \
        (ZERO_OR_COMPILE_ERROR(0)))))))))))))
 
#define SYS_INIT(init_fn, level, prio)                                         \
        SYS_INIT_NAMED(init_fn, init_fn, level, prio)
 
#define SYS_INIT_NAMED(name, init_fn_, level, prio)                                       \
        static const Z_DECL_ALIGN(struct init_entry)                                      \
                Z_INIT_ENTRY_SECTION(level, prio, 0) __used __noasan                      \
                Z_INIT_ENTRY_NAME(name) = {.init_fn = {.sys = (init_fn_)},                \
                        Z_INIT_SYS_INIT_DEV_NULL}
 
#ifdef __cplusplus
}
#endif
 
#endif /* ZEPHYR_INCLUDE_INIT_H_ */