本文來源電子發燒友社區，作者：李先生， 帖子地址：https://bbs.elecfans.com/jishu_2307381_1_1.html



前言

磨刀不誤砍材工,為了方便后面開發,先對照著打印信息和代碼,對啟動過程進行分析,對程序執行過程有個大致了解。

程序入口點,內核啟動

device/soc/esp/esp32/components/esp_system/port/cpu_start.c

call_start_cpu0

打印如下

I (370) cpu_start: Pro cpu up.

I (376) cpu_start: Single core mode

device/soc/esp/esp32/components/esp_system/startup.c

start_cpu0_default

打印如下

I (371) cpu_start: Pro cpu start user code

I (373) cpu_start: cpu freq: 160000000

I (378) cpu_start: Application information:

I (380) cpu_start: Project name:     spp_client_demo

I (383) cpu_start: App version:      1

I (389) cpu_start: Compile time:     Sep 23 2022 21:28:08

I (393) cpu_start: ELF file SHA256:  aa63348688c93d38...

I (394) cpu_start: ESP-IDF:          v4.3.1-dirty

device/soc/esp/esp32/components/heap/heap_caps_init.c

heap_caps_init

打印如下

I (94) heap_init: Initializing. RAM available for dynamic allocation:

I (118) heap_init: At 3FF80000 len 00002000 (8 KiB): RTCRAM

I (118) heap_init: At 3FFAFF10 len 000000F0 (0 KiB): DRAM

I (118) heap_init: At 3FFB6388 len 00001C78 (7 KiB): DRAM

I (118) heap_init: At 3FFB9A20 len 00004108 (16 KiB): DRAM

I (118) heap_init: At 3FFC5128 len 0001AED8 (107 KiB): DRAM

I (118) heap_init: At 3FFE0440 len 0001FBC0 (126 KiB): D/IRAM

I (118) heap_init: At 40078000 len 00008000 (32 KiB): IRAM

I (118) heap_init: At 400905E0 len 0000FA20 (62 KiB): IRAM

kernel/liteos_m/kernel/src/los_init.c

LOS_KernelInit

打印如下

entering kernel init...

kernel/liteos_m/kernel/src/los_sched.c

OsSchedStart

打印如下

Entering scheduler

系統初始化

deviceboardopenvalleyniobeu4liteos_mtargetsrctarget_startup.c

OHOS_SystemInitEntry ->

int err;

printf("Code Build Time:%s %sn", __DATE__, __TIME__);

before_ohos_run();

esp_err_t ret = nvs_flash_init();

if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {

    nvs_flash_erase();

    ret = nvs_flash_init();

}

DeviceWifiStart();

init_trace_system();

err = DeviceManagerStart();

if (err) {

    printf("DeviceManagerStart.ret=0x%Xn", err);

}

OHOS_SystemInit();

ohos_app_main();

return NULL;

l 先打印編譯時間

l before_ohos_run調用鉤子函數BEFORE_OHOS_RUN_FUNC_ENTRY

該函數由#define BEFORE_OHOS_RUN(func) void *BEFORE_OHOS_RUN_FUNC_ENTRY = (func)宏定義,實際是一個全局函數指針變量

l nvs_flash_init進行flash初始化

對應打印如下

l DeviceWifiStart

l init_trace_system 注冊打印輸出接口g_hilogOutputProc賦值為HilogProc_Impl

OutputLog即調用該函數打印輸出

l DeviceManagerStart

l OHOS_SystemInit

l ohos_app_main調用用戶代碼

Code Build Time:Sep 23 2022 21:52:39

I (321) spi_flash: detected chip: generic

I (218) spi_flash: flash io: dio

I (18) wifi:wifi driver task: 6, prio:23, stack:6656, core=0

I (56) system_api: Base MAC address is not set

I (156) system_api: read default base MAC address from EFUSE

I (18) wifi:wifi firmware version: 88c8747

I (28) wifi:wifi certification version: v7.0

I (28) wifi:config NVS flash: disabled

I (28) wifi:config nano formating: disabled

I (38) wifi:Init data frame dynamic rx buffer num: 32

I (38) wifi:Init management frame dynamic rx buffer num: 32

I (48) wifi:Init management short buffer num: 32

I (48) wifi:Init dynamic tx buffer num: 32

I (48) wifi:Init static rx buffer size: 1600

I (58) wifi:Init static rx buffer num: 10

I (58) wifi:Init dynamic rx buffer num: 32

I (141) wifi_init: rx ba win: 6

I (145) wifi_init: tcpip mbox: 32

I (146) wifi_init: udp mbox: 6

I (147) wifi_init: tcp mbox: 6

I (148) wifi_init: tcp tx win: 5744

I (149) wifi_init: tcp rx win: 5744

I (150) wifi_init: tcp mss: 1440

I (157) wifi_init: WiFi IRAM OP enabled

hilog will init.

hievent will init.

hievent init success.

01-01 00:00:00.247 0 48 D 0/HIVIEW: log limit init success.

Littlefs.mount=/Openvalley addr=0x312000 size=832K OK!!!

01-01 00:00:00.257 0 48 I 1/SAMGR: Bootstrap core services(count:1).

01-01 00:00:00.263 0 48 I 1/SAMGR: Init service:0x3f401224

hiview init success.

01-01 00:00:00.269 0 112 I 1/SAMGR: Init service 0x3f401224 20ms> success!

01-01 00:00:00.277 0 112 I 1/SAMGR: Initialized all core system services!

01-01 00:00:00.283 0 112 I 1/SAMGR: Goto next boot step return code:-6

用戶代碼執行

用戶代碼中,例如

OHOS_APP_RUN(Niobeu4HelloWorld);

定義全局函數指針變量OHOS_APP_FUNC_ENTRY,并賦值。

其宏定義如下

#define OHOS_APP_RUN(func) void *OHOS_APP_FUNC_ENTRY = (func)

在如下

deviceboardopenvalleyniobeu4liteos_mtargetsrctarget_startup.c

ohos_app_main

調用OHOS_APP_FUNC_ENTRY即調用Niobeu4HelloWorld。

對應打印如下

<--------------- OHOS Application Start Here --------------->

---

* [Openvalley/Niobeu4] *
* Hello world.    *

---