1 /* 2 * Copyright (c) 2015 Intel Corporation. 3 * 4 * SPDX-License-Identifier: Apache-2.0 5 */ 6 7 #ifndef ZEPHYR_INCLUDE_INIT_H_ 8 #define ZEPHYR_INCLUDE_INIT_H_ 9 10 #include <stdint.h> 11 #include <stddef.h> 12 13 #include <zephyr/sys/util.h> 14 #include <zephyr/toolchain.h> 15 16 #ifdef __cplusplus 17 extern "C" { 18 #endif 19 20 /** 21 * @defgroup sys_init System Initialization 22 * @ingroup os_services 23 * 24 * Zephyr offers an infrastructure to call initialization code before `main`. 25 * Such initialization calls can be registered using SYS_INIT() or 26 * SYS_INIT_NAMED() macros. By using a combination of initialization levels and 27 * priorities init sequence can be adjusted as needed. The available 28 * initialization levels are described, in order, below: 29 * 30 * - `EARLY`: Used very early in the boot process, right after entering the C 31 * domain (``z_cstart()``). This can be used in architectures and SoCs that 32 * extend or implement architecture code and use drivers or system services 33 * that have to be initialized before the Kernel calls any architecture 34 * specific initialization code. 35 * - `PRE_KERNEL_1`: Executed in Kernel's initialization context, which uses 36 * the interrupt stack. At this point Kernel services are not yet available. 37 * - `PRE_KERNEL_2`: Same as `PRE_KERNEL_1`. 38 * - `POST_KERNEL`: Executed after Kernel is alive. From this point on, Kernel 39 * primitives can be used. 40 * - `APPLICATION`: Executed just before application code (`main`). 41 * - `SMP`: Only available if @kconfig{CONFIG_SMP} is enabled, specific for 42 * SMP. 43 * 44 * Initialization priority can take a value in the range of 0 to 99. 45 * 46 * @note The same infrastructure is used by devices. 47 * @{ 48 */ 49 50 struct device; 51 52 /** 53 * @brief Structure to store initialization entry information. 54 * 55 * @internal 56 * Init entries need to be defined following these rules: 57 * 58 * - Their name must be set using Z_INIT_ENTRY_NAME(). 59 * - They must be placed in a special init section, given by 60 * Z_INIT_ENTRY_SECTION(). 61 * - They must be aligned, e.g. using Z_DECL_ALIGN(). 62 * 63 * See SYS_INIT_NAMED() for an example. 64 * @endinternal 65 */ 66 struct init_entry { 67 /** 68 * If the init function belongs to a SYS_INIT, this field stored the 69 * initialization function, otherwise it is set to NULL. 70 */ 71 int (*init_fn)(void); 72 /** 73 * If the init entry belongs to a device, this fields stores a 74 * reference to it, otherwise it is set to NULL. 75 */ 76 const struct device *dev; 77 }; 78 79 /** @cond INTERNAL_HIDDEN */ 80 81 /* Helper definitions to evaluate level equality */ 82 #define Z_INIT_EARLY_EARLY 1 83 #define Z_INIT_PRE_KERNEL_1_PRE_KERNEL_1 1 84 #define Z_INIT_PRE_KERNEL_2_PRE_KERNEL_2 1 85 #define Z_INIT_POST_KERNEL_POST_KERNEL 1 86 #define Z_INIT_APPLICATION_APPLICATION 1 87 #define Z_INIT_SMP_SMP 1 88 89 /* Init level ordinals */ 90 #define Z_INIT_ORD_EARLY 0 91 #define Z_INIT_ORD_PRE_KERNEL_1 1 92 #define Z_INIT_ORD_PRE_KERNEL_2 2 93 #define Z_INIT_ORD_POST_KERNEL 3 94 #define Z_INIT_ORD_APPLICATION 4 95 #define Z_INIT_ORD_SMP 5 96 97 /** 98 * @brief Obtain init entry name. 99 * 100 * @param init_id Init entry unique identifier. 101 */ 102 #define Z_INIT_ENTRY_NAME(init_id) _CONCAT(__init_, init_id) 103 104 /** 105 * @brief Init entry section. 106 * 107 * Each init entry is placed in a section with a name crafted so that it allows 108 * linker scripts to sort them according to the specified 109 * level/priority/sub-priority. 110 */ 111 #define Z_INIT_ENTRY_SECTION(level, prio, sub_prio) \ 112 __attribute__((__section__( \ 113 ".z_init_" #level STRINGIFY(prio)"_" STRINGIFY(sub_prio)"_"))) 114 115 /** @endcond */ 116 117 /** 118 * @brief Obtain the ordinal for an init level. 119 * 120 * @param level Init level (EARLY, PRE_KERNEL_1, PRE_KERNEL_2, POST_KERNEL, 121 * APPLICATION, SMP). 122 * 123 * @return Init level ordinal. 124 */ 125 #define INIT_LEVEL_ORD(level) \ 126 COND_CODE_1(Z_INIT_EARLY_##level, (Z_INIT_ORD_EARLY), \ 127 (COND_CODE_1(Z_INIT_PRE_KERNEL_1_##level, (Z_INIT_ORD_PRE_KERNEL_1), \ 128 (COND_CODE_1(Z_INIT_PRE_KERNEL_2_##level, (Z_INIT_ORD_PRE_KERNEL_2), \ 129 (COND_CODE_1(Z_INIT_POST_KERNEL_##level, (Z_INIT_ORD_POST_KERNEL), \ 130 (COND_CODE_1(Z_INIT_APPLICATION_##level, (Z_INIT_ORD_APPLICATION), \ 131 (COND_CODE_1(Z_INIT_SMP_##level, (Z_INIT_ORD_SMP), \ 132 (ZERO_OR_COMPILE_ERROR(0))))))))))))) 133 134 /** 135 * @brief Register an initialization function. 136 * 137 * The function will be called during system initialization according to the 138 * given level and priority. 139 * 140 * @param init_fn Initialization function. 141 * @param level Initialization level. Allowed tokens: `EARLY`, `PRE_KERNEL_1`, 142 * `PRE_KERNEL_2`, `POST_KERNEL`, `APPLICATION` and `SMP` if 143 * @kconfig{CONFIG_SMP} is enabled. 144 * @param prio Initialization priority within @p _level. Note that it must be a 145 * decimal integer literal without leading zeroes or sign (e.g. `32`), or an 146 * equivalent symbolic name (e.g. `#define MY_INIT_PRIO 32`); symbolic 147 * expressions are **not** permitted (e.g. 148 * `CONFIG_KERNEL_INIT_PRIORITY_DEFAULT + 5`). 149 */ 150 #define SYS_INIT(init_fn, level, prio) \ 151 SYS_INIT_NAMED(init_fn, init_fn, level, prio) 152 153 /** 154 * @brief Register an initialization function (named). 155 * 156 * @note This macro can be used for cases where the multiple init calls use the 157 * same init function. 158 * 159 * @param name Unique name for SYS_INIT entry. 160 * @param init_fn_ See SYS_INIT(). 161 * @param level See SYS_INIT(). 162 * @param prio See SYS_INIT(). 163 * 164 * @see SYS_INIT() 165 */ 166 #define SYS_INIT_NAMED(name, init_fn_, level, prio) \ 167 static const Z_DECL_ALIGN(struct init_entry) \ 168 Z_INIT_ENTRY_SECTION(level, prio, 0) __used __noasan \ 169 Z_INIT_ENTRY_NAME(name) = {.init_fn = (init_fn_), .dev = NULL} \ 170 171 /** @} */ 172 173 #ifdef __cplusplus 174 } 175 #endif 176 177 #endif /* ZEPHYR_INCLUDE_INIT_H_ */ 178
