/* * Copyright (c) 2015 Intel Corporation. * * SPDX-License-Identifier: Apache-2.0 */ #ifndef ZEPHYR_INCLUDE_INIT_H_ #define ZEPHYR_INCLUDE_INIT_H_ #include #include #include #include #ifdef __cplusplus extern "C" { #endif /** * @defgroup sys_init System Initialization * @ingroup os_services * * Zephyr offers an infrastructure to call initialization code before `main`. * Such initialization calls can be registered using SYS_INIT() or * SYS_INIT_NAMED() macros. By using a combination of initialization levels and * priorities init sequence can be adjusted as needed. The available * initialization levels are described, in order, below: * * - `EARLY`: Used very early in the boot process, right after entering the C * domain (``z_cstart()``). This can be used in architectures and SoCs that * extend or implement architecture code and use drivers or system services * that have to be initialized before the Kernel calls any architecture * specific initialization code. * - `PRE_KERNEL_1`: Executed in Kernel's initialization context, which uses * the interrupt stack. At this point Kernel services are not yet available. * - `PRE_KERNEL_2`: Same as `PRE_KERNEL_1`. * - `POST_KERNEL`: Executed after Kernel is alive. From this point on, Kernel * primitives can be used. * - `APPLICATION`: Executed just before application code (`main`). * - `SMP`: Only available if @kconfig{CONFIG_SMP} is enabled, specific for * SMP. * * Initialization priority can take a value in the range of 0 to 99. * * @note The same infrastructure is used by devices. * @{ */ struct device; /** * @brief Initialization function for init entries. * * Init entries support both the system initialization and the device * APIs. Each API has its own init function signature; hence, we have a * union to cover both. */ union init_function { /** * System initialization function. * * @retval 0 On success * @retval -errno If init fails. */ int (*sys)(void); /** * Device initialization function. * * @param dev Device instance. * * @retval 0 On success * @retval -errno If device initialization fails. */ int (*dev)(const struct device *dev); }; /** * @brief Structure to store initialization entry information. * * @internal * Init entries need to be defined following these rules: * * - Their name must be set using Z_INIT_ENTRY_NAME(). * - They must be placed in a special init section, given by * Z_INIT_ENTRY_SECTION(). * - They must be aligned, e.g. using Z_DECL_ALIGN(). * * See SYS_INIT_NAMED() for an example. * @endinternal */ struct init_entry { /** Initialization function. */ union init_function init_fn; /** * If the init entry belongs to a device, this fields stores a * reference to it, otherwise it is set to NULL. */ const struct device *dev; }; /** @cond INTERNAL_HIDDEN */ /* 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 /** * @brief Obtain init entry name. * * @param init_id Init entry unique identifier. */ #define Z_INIT_ENTRY_NAME(init_id) _CONCAT(__init_, init_id) /** * @brief Init entry section. * * Each init entry is placed in a section with a name crafted so that it allows * linker scripts to sort them according to the specified level/priority. */ #define Z_INIT_ENTRY_SECTION(level, prio) \ __attribute__((__section__(".z_init_" #level STRINGIFY(prio)"_"))) /** @endcond */ /** * @brief Obtain the ordinal for an init level. * * @param level Init level (EARLY, PRE_KERNEL_1, PRE_KERNEL_2, POST_KERNEL, * APPLICATION, SMP). * * @return Init level ordinal. */ #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))))))))))))) /** * @brief Register an initialization function. * * The function will be called during system initialization according to the * given level and priority. * * @param init_fn Initialization function. * @param level Initialization level. Allowed tokens: `EARLY`, `PRE_KERNEL_1`, * `PRE_KERNEL_2`, `POST_KERNEL`, `APPLICATION` and `SMP` if * @kconfig{CONFIG_SMP} is enabled. * @param prio Initialization priority within @p _level. Note that it must be a * decimal integer literal without leading zeroes or sign (e.g. `32`), or an * equivalent symbolic name (e.g. `#define MY_INIT_PRIO 32`); symbolic * expressions are **not** permitted (e.g. * `CONFIG_KERNEL_INIT_PRIORITY_DEFAULT + 5`). */ #define SYS_INIT(init_fn, level, prio) \ SYS_INIT_NAMED(init_fn, init_fn, level, prio) /** * @brief Register an initialization function (named). * * @note This macro can be used for cases where the multiple init calls use the * same init function. * * @param name Unique name for SYS_INIT entry. * @param init_fn_ See SYS_INIT(). * @param level See SYS_INIT(). * @param prio See SYS_INIT(). * * @see SYS_INIT() */ #define SYS_INIT_NAMED(name, init_fn_, level, prio) \ static const Z_DECL_ALIGN(struct init_entry) \ Z_INIT_ENTRY_SECTION(level, prio) __used __noasan \ Z_INIT_ENTRY_NAME(name) = { \ .init_fn = {.sys = (init_fn_)}, \ .dev = NULL, \ } /** @} */ #ifdef __cplusplus } #endif #endif /* ZEPHYR_INCLUDE_INIT_H_ */