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 Initialization function for init entries. 54 * 55 * Init entries support both the system initialization and the device 56 * APIs. Each API has its own init function signature; hence, we have a 57 * union to cover both. 58 */ 59 union init_function { 60 /** 61 * System initialization function. 62 * 63 * @retval 0 On success 64 * @retval -errno If init fails. 65 */ 66 int (*sys)(void); 67 /** 68 * Device initialization function. 69 * 70 * @param dev Device instance. 71 * 72 * @retval 0 On success 73 * @retval -errno If device initialization fails. 74 */ 75 int (*dev)(const struct device *dev); 76 }; 77 78 /** 79 * @brief Structure to store initialization entry information. 80 * 81 * @internal 82 * Init entries need to be defined following these rules: 83 * 84 * - Their name must be set using Z_INIT_ENTRY_NAME(). 85 * - They must be placed in a special init section, given by 86 * Z_INIT_ENTRY_SECTION(). 87 * - They must be aligned, e.g. using Z_DECL_ALIGN(). 88 * 89 * See SYS_INIT_NAMED() for an example. 90 * @endinternal 91 */ 92 struct init_entry { 93 /** Initialization function. */ 94 union init_function init_fn; 95 /** 96 * If the init entry belongs to a device, this fields stores a 97 * reference to it, otherwise it is set to NULL. 98 */ 99 const struct device *dev; 100 }; 101 102 /** @cond INTERNAL_HIDDEN */ 103 104 /* Helper definitions to evaluate level equality */ 105 #define Z_INIT_EARLY_EARLY 1 106 #define Z_INIT_PRE_KERNEL_1_PRE_KERNEL_1 1 107 #define Z_INIT_PRE_KERNEL_2_PRE_KERNEL_2 1 108 #define Z_INIT_POST_KERNEL_POST_KERNEL 1 109 #define Z_INIT_APPLICATION_APPLICATION 1 110 #define Z_INIT_SMP_SMP 1 111 112 /* Init level ordinals */ 113 #define Z_INIT_ORD_EARLY 0 114 #define Z_INIT_ORD_PRE_KERNEL_1 1 115 #define Z_INIT_ORD_PRE_KERNEL_2 2 116 #define Z_INIT_ORD_POST_KERNEL 3 117 #define Z_INIT_ORD_APPLICATION 4 118 #define Z_INIT_ORD_SMP 5 119 120 /** 121 * @brief Obtain init entry name. 122 * 123 * @param init_id Init entry unique identifier. 124 */ 125 #define Z_INIT_ENTRY_NAME(init_id) _CONCAT(__init_, init_id) 126 127 /** 128 * @brief Init entry section. 129 * 130 * Each init entry is placed in a section with a name crafted so that it allows 131 * linker scripts to sort them according to the specified level/priority. 132 */ 133 #define Z_INIT_ENTRY_SECTION(level, prio) \ 134 __attribute__((__section__(".z_init_" #level STRINGIFY(prio)"_"))) 135 136 /** @endcond */ 137 138 /** 139 * @brief Obtain the ordinal for an init level. 140 * 141 * @param level Init level (EARLY, PRE_KERNEL_1, PRE_KERNEL_2, POST_KERNEL, 142 * APPLICATION, SMP). 143 * 144 * @return Init level ordinal. 145 */ 146 #define INIT_LEVEL_ORD(level) \ 147 COND_CODE_1(Z_INIT_EARLY_##level, (Z_INIT_ORD_EARLY), \ 148 (COND_CODE_1(Z_INIT_PRE_KERNEL_1_##level, (Z_INIT_ORD_PRE_KERNEL_1), \ 149 (COND_CODE_1(Z_INIT_PRE_KERNEL_2_##level, (Z_INIT_ORD_PRE_KERNEL_2), \ 150 (COND_CODE_1(Z_INIT_POST_KERNEL_##level, (Z_INIT_ORD_POST_KERNEL), \ 151 (COND_CODE_1(Z_INIT_APPLICATION_##level, (Z_INIT_ORD_APPLICATION), \ 152 (COND_CODE_1(Z_INIT_SMP_##level, (Z_INIT_ORD_SMP), \ 153 (ZERO_OR_COMPILE_ERROR(0))))))))))))) 154 155 /** 156 * @brief Register an initialization function. 157 * 158 * The function will be called during system initialization according to the 159 * given level and priority. 160 * 161 * @param init_fn Initialization function. 162 * @param level Initialization level. Allowed tokens: `EARLY`, `PRE_KERNEL_1`, 163 * `PRE_KERNEL_2`, `POST_KERNEL`, `APPLICATION` and `SMP` if 164 * @kconfig{CONFIG_SMP} is enabled. 165 * @param prio Initialization priority within @p _level. Note that it must be a 166 * decimal integer literal without leading zeroes or sign (e.g. `32`), or an 167 * equivalent symbolic name (e.g. `#define MY_INIT_PRIO 32`); symbolic 168 * expressions are **not** permitted (e.g. 169 * `CONFIG_KERNEL_INIT_PRIORITY_DEFAULT + 5`). 170 */ 171 #define SYS_INIT(init_fn, level, prio) \ 172 SYS_INIT_NAMED(init_fn, init_fn, level, prio) 173 174 /** 175 * @brief Register an initialization function (named). 176 * 177 * @note This macro can be used for cases where the multiple init calls use the 178 * same init function. 179 * 180 * @param name Unique name for SYS_INIT entry. 181 * @param init_fn_ See SYS_INIT(). 182 * @param level See SYS_INIT(). 183 * @param prio See SYS_INIT(). 184 * 185 * @see SYS_INIT() 186 */ 187 #define SYS_INIT_NAMED(name, init_fn_, level, prio) \ 188 static const Z_DECL_ALIGN(struct init_entry) \ 189 Z_INIT_ENTRY_SECTION(level, prio) __used __noasan \ 190 Z_INIT_ENTRY_NAME(name) = { \ 191 .init_fn = {.sys = (init_fn_)}, \ 192 .dev = NULL, \ 193 } 194 195 /** @} */ 196 197 #ifdef __cplusplus 198 } 199 #endif 200 201 #endif /* ZEPHYR_INCLUDE_INIT_H_ */ 202
