LiteOS-Reading/src/doc/LiteOS_Code_Info_en.md

LiteOS Code Entry

The LiteOS entry is in the main.c file of a project. The basic process is as follows:

INT32 main(VOID)
{
    BoardConfig();
    HardwareInit();

    PRINT_RELEASE("\n********Hello Huawei LiteOS********\n"
                  "\nLiteOS Kernel Version : %s\n"
                  "build data : %s %s\n\n"
                  "**********************************\n",
                  HW_LITEOS_KERNEL_VERSION_STRING, __DATE__, __TIME__);

    UINT32 ret = OsMain();
    if (ret != LOS_OK) {
        return LOS_NOK;
    }

    OsStart();

    return 0;
}

Configure the memory end address using BoardConfig(), initialize the hardware using HardwareInit(), and print the version information of Huawei LiteOS.

Execute OsMain() to initialize the Huawei LiteOS kernel and routines. A user task is created in the OsMain() function, and the task processing function is app_init().

Call OsStart() to start task scheduling. Huawei LiteOS starts to work properly.

Description of the LiteOS Code Directory Structure

Source code stored in each directory is as follows:

Level-1 Directory	Level-2 Directory	Level-3 Directory	Description
arch	arm	cortex_a_r	Cortex-A architecture support
		cortex_m	Cortex-M architecture support
	arm64		ARM64 architecture support
build			Configuration and scripts required for building LiteOS
compat	cmsis		CMSIS-RTOS 1.0 and 2.0 APIs provided by LiteOS
components	ai		MindSpore-based AI operator library implementation
	connectivity	agent_tiny	agent_tiny, which is a device-cloud interconnect componentcontaining the public header file, sample code, client implementation code, and OS adaptation layer code
		lwm2m	Implementation of the LwM2M protocol
		mqtt	Implementation of the MQTT open-source protocol
		nb_iot	LiteOS NB-IoT API
	fs		File systems, including vfs, spiffs, ramfs, littlefs, kifs, fatfs and devfs
	gui		Open-source LittlevGL graphics library
	language		Language-related components, including lua
	lib	cjson	C language JSON library
	log		Log level control
	media		Media-related components, including Opus and libpng
	net	at_device	AT device adaptation layer
		at_frame	LiteOS AT framework API
		lwip/lwip_port	lwIP driver and OS adaptation code
		lwip/lwip-2.1.2	Implementation of the lwIP protocol
		lwip/ppp_port	Support for the PPP port of the lwIP protocol
		sal	Socket communication support
	ota		Firmware upgrade code
	security	mbedtls/mbedtls_port	mbed TLS OS adaptation code
		mbedtls/mbedtl-2.16.8	mbed TLS protocol implementation
	sensorhub	include	Sensor manager header file
		src	Sensor manager source code implementation
	utility		Parsing tools, including bidireference, freetype, iconv, iniparser, json-c and libxml2
demos	agenttiny_lwm2m		LwM2M protocol demo
	agenttiny_mqtt		MQTT protocol demo
	ai		AI demo
	dtls_server		DTLS protocol demo
	fs		File system demo
	gui		GUI demo
	ipv6_client		IPv6 protocol demo
	kernel	api	Demo code example for developers to test the LiteOS kernel
		include	Directory of API function header files
	language		Language-related component demo
	lms		LMS demo
	media		Media-related component demo
	nbiot_without_atiny		NB-IoT demo
	sensorhub	gyro	Demo for periodically reading the original data of the MPU6050 gyroscope based on the sensorhub sensor framework
	trace		Trace demo
	utility		Parser demo
doc			LiteOS-related documents, such as the usage guide and API description
include			Header files which each components module depends on
kernel	base		LiteOS basic kernel code, providing functions such as tasks, interrupts, software timers, queues, events, semaphores, mutex locks, and ticks
		debug	LiteOS kernel debugging code, including the debugging of queues, semaphores, mutexes, and task scheduling
		include	Header files internally used by the LiteOS basic kernel
		mem	Code related to memory management in LiteOS
		sched	Task scheduling, including multi-core scheduling
		shellcmd	Shell commands related to the basic kernel on LiteOS, including memcheck, task, systeminfo, and swtmr
	extended	cppsupport	Bottom-layer APIs for the C++ compatible adaptation layer
		cpup	cpup
		include	Header files required by the extended directory
		lms	Library file of LMS (used to check the validity of memory operations in real time)
		lowpower	Code related to the low-power framework
		trace	Event tracing, which is used to record the system running track in real time
	include		LiteOS open-source kernel header file
	init		LiteOS kernel initialization code
lib	huawei_libc		LiteOS Huawei-developed libc library and adapted POSIX API
	libc		The musl libc library for LiteOS adaptation
	libsec		Huawei security function library
	zlib		Open-source zlib library
osdepends	liteos		Some OS adaptation interfaces provided by LiteOS
shell			Implementing the code of the shell command and supporting the basic debugging function
targets	bsp		General board support package
	Cloud_STM32F429IGTx_FIRE		Wildfire STM32F429 (ARM Cortex M4) development project source code package
	qemu-virt-a53		QEMU development project source code package of Coretex-A53
	realview-pbx-a9		QEMU development project source code package of Coretex-A9
	STM32F072_Nucleo		Source code package of the development project for the STM32F072_Nucleo (ARM Cortex-M0) development board
	STM32F103_FIRE_Arbitrary		Development project source code package of the Wildfire STM32F103 (ARM Cortex-M3) Hegemony development board
	STM32F407_ATK_Explorer		STM32F407 (ARM Cortex-M4) explorer board development project source code package
	STM32F769IDISCOVERY		Source code package of the development project for the STM32F769IDISCOVERY (ARM Cortex-M7) development board
	STM32L4R9I_Discovery		Source code package of the development project for the STM32L4R9IDISCOVERY (ARM Cortex-M4) development board
	STM32L431_BearPi		Source code package of the development project for BearPi STM32L431 (ARM Cortex-M4) development board
	STM32L476_NB476		Source code package of the Shenzhen maker STM32L476 (ARM Cortex-M4) development board
	STM32L496_Nucleo		Source code package of the development project for the STM32L496 NUCLEO-144 (ARM Cortex-M4) development board
tools	build		Configuration file of the development board supported by LiteOS
	menuconfig		The menuconfig script required for building LiteOS
Makefile			LiteOS Makefile
.config			Configuration file of the development board. If you do not reselect a development board, the configuration file of the wildfire challenger STM32F429 development board is used by default.