NuttX 启动流程

最新推荐文章于 2025-09-03 21:52:57 发布
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本文详细介绍了嵌入式实时操作系统NuttX 7.1版本在STM32平台上的启动过程。从处理器的第一条指令开始，经过时钟初始化、外设配置、操作系统初始化等多个步骤，最终创建初始任务并进入空闲任务循环。
（嵌入式实时操作系统 rtos nuttx 7.1 stm32 源代码分析）
NuttX 启动流程

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 __start--                                 #处理器执行的第一条指令  
         |  
         v  
    stm32_clockconfig()------              #初始化时钟  
                            |  
                            v  
                  rcc_reset()              #复位rcc  
                  stm32_stdclockconfig()   #初始化标准时钟  
                  rcc_enableperipherals()  #使能外设时钟  
                            |  
         --------------------  
         |  
         v  
    stm32_fpuconfig()                      #配置fpu，shenzhou/nsh未调用  
    stm32_lowsetup()                       #基本初始化串口，之后可以使用up_lowputc()  
    stm32_gpioinit()                       #初始化gpio，只是调用stm32_gpioremap()设置重映射  
    up_earlyserialinit()                   #初始化串口，之后可以使用up_putc()  
    stm32_boardinitialize()--              #板级初始化  
                            |  
                            v  
                  stm32_spiinitialize()    #初始化spi，只是调用stm32_configgpio()设置gpio  
                  stm32_usbinitialize()    #初始化usb，只是调用stm32_configgpio()设置gpio  
                  board_led_initialize()   #初始化led，只是调用stm32_configgpio()设置gpio  
                            |  
         --------------------  
         |  
         v  
    os_start()---------------              #初始化操作系统  
                            |  
                            v  
                  dq_init()                #初始化各种状态的任务列表（置为null）  
                  g_pidhash[i]=            #初始化唯一可以确定的元素--进程ID  
                  g_pidhash[PIDHASH(0)]=   #分配空闲任务的进程ID为0  
                  g_idletcb=               #初始化空闲任务的任务控制块  
                  sem_initialize()--       #初始化信号量  
                                   |  
                                   v  
                        dq_init()          #将信号量队列置为null  
                        sem_initholders()  #初始化持有者结构以支持优先级继承，shenzhou/nsh未调用  
                                   |  
                            --------  
                            |  
                            v  
                  up_allocate_heap()       #分配用户模式的堆（设置堆的起点和大小）  
                  kumm_initialize()        #初始化用户模式的堆  
                  up_allocate_kheap()      #分配内核模式的堆，shenzhou/nsh未调用  
                  kmm_initialize()         #初始化内核模式的堆，shenzhou/nsh未调用  
                  task_initialize()        #初始化任务数据结构，shenzhou/nsh未调用  
                  irq_initialize()         #将所有中断向量都指向同一个异常中断处理程序  
                  wd_initialize()          #初始化看门狗数据结构  
                  clock_initialize()       #初始化rtc  
                  timer_initialize()       #配置POSIX定时器  
                  sig_initialize()         #初始化信号  
                  mq_initialize()          #初始化命名消息队列  
                  pthread_initialize()     #初始化线程特定的数据，空函数  
                  fs_initialize()---       #初始化文件系统  
                                   |  
                                   v  
                        sem_init()         #初始化节点信号量为1  
                        files_initialize() #初始化文件数组，空函数  
                                   |  
                            --------  
                            |  
                            v  
                  net_initialize()--       #初始化网络  
                                   |  
                                   v  
                        uip_initialize()   #初始化uIP层  
                        net_initroute()    #初始化路由表，shenzhou/nsh未调用  
                        netdev_seminit()   #初始化网络设备信号量  
                        arptimer_init()    #初始化ARP定时器  
                                   |  
                            --------  
                            |  
                            v  
                  up_initialize()---       #处理器特定的初始化  
                                   |  
                                   v  
                        up_calibratedelay()#校准定时器  
                        up_addregion()     #增加额外的内存段  
                        up_irqinitialize() #设置中断优先级，关联硬件异常处理函数  
                        up_pminitialize()  #初始化电源管理，shenzhou/nsh未调用  
                        up_dmainitialize() #初始化DMA，shenzhou/nsh未调用  
                        up_timerinit()     #初始化定时器中断  
                        devnull_register() #注册/dev/null  
                        devzero_register() #注册/dev/zero，shenzhou/nsh未调用  
                        up_serialinit()    #注册串口控制台/dev/console和串口/dev/ttyS0  
                        up_rnginitialize() #初始化并注册随机数生成器，shenzhou/nsh未调用  
                        up_netinitialize() #初始化网络，是arch/arm/src/chip/stm32_eth.c中的  
                        up_usbinitialize() #初始化usb驱动，shenzhou/nsh未调用  
                        board_led_on()     #打开中断使能led，但很快会被其它地方的led操作改变状态  
                                   |  
                            --------  
                            |  
                            v  
                  lib_initialize()         #初始化c库，空函数  
                  group_allocate()         #分配空闲组  
                  group_setupidlefiles()   #在空闲任务上创建stdout、stderr、stdin  
                  group_initialize()       #完全初始化空闲组  
                  os_bringup()------       #创建初始任务  
                                   |  
                                   v  
                        KEKERNEL_THREAD()  #启动内核工作者线程  
                        board_initialize() #最后一刻的板级初始化，shenzhou/nsh未调用  
                        TASK_CREATE()      #启动默认应用程序  
                                   |  
                            --------  
                            |  
                            v  
                  for up_idle()            #空闲任务循环  
                            |  
         --------------------  
         |  
         v  
    for(;;)                                #不应该到达这里  