目录
摘要
本节主要记录自己学px4的代码架构与Ardupilot代码架构对比文档，欢迎批评指正。
（1）px4与apm固件的区别与联系
（2）px4与apm每个文件夹的作用
（3）px4与apm无人机的启动过程
第一节：px4与apm的区别与联系
（1）pixhawk
（2）APM
（3）px4—Firmware
（4）apm—Ardupilot
第二节：px4与apm每个文件夹的作用
（1）px4代码代码架构
1>整理目录
2>每个文件夹的作用
（2）apm代码代码架构
1>整理目录
2>每个文件夹的作用
第三节：px4与apm无人机的启动过程
这里只讲解Nuttx启动到ArduCopter多旋翼入口函数的过程，Bootloader到Nuttx的过程将在：Bootloader启动分析中讲解。
1.px4固件启动过程
（1）Bootloader启动后，单片机的入口函数：stm32_start.c
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需要思考的问题：这个启动过程是STM32F427还是STM32F103的入口，或者两个同时都有
//复位后的入口函数：This is the reset entry point.
void __start(void)
{
const uint32_t *src;
uint32_t *dest;
#ifdef CONFIG_ARMV7M_STACKCHECK
/* Set the stack limit before we attempt to call any functions */
__asm__ volatile ("sub r10, sp, %0" : : "r" (CONFIG_IDLETHREAD_STACKSIZE - 64) : );
#endif
/* Configure the UART so that we can get debug output as soon as possible */
stm32_clockconfig(); //初始化时钟
stm32_fpuconfig(); //配置FPU(浮点运算)
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
showprogress('A'); //输出A
/* Clear .bss. We'll do this inline (vs. calling memset) just to be
* certain that there are no issues with the state of global variables.
*/
for (dest = _START_BSS; dest < _END_BSS; )
{
*dest++ = 0;
}
showprogress('B');
/* Move the initialized data section from his temporary holding spot in
* FLASH into the correct place in SRAM. The correct place in SRAM is
* give by _sdata and _edata. The temporary location is in FLASH at the
* end of all of the other read-only data (.text, .rodata) at _eronly.
*/
for (src = _DATA_INIT, dest = _START_DATA; dest < _END_DATA; )
{
*dest++ = *src++;
}
showprogress('C');
#ifdef CONFIG_ARMV7M_ITMSYSLOG
/* Perform ARMv7-M ITM SYSLOG initialization */
itm_syslog_initialize();
#endif
/* Perform early serial initialization */
#ifdef USE_EARLYSERIALINIT
up_earlyserialinit(); //初始化串口，之后可以使用up_putc()
#endif
showprogress('D');
/* For the case of the separate user-/kernel-space build, perform whatever
* platform specific initialization of the user memory is required.
* Normally this just means initializing the user space .data and .bss
* segments.
*/
#ifdef CONFIG_BUILD_PROTECTED
stm32_userspace();
showprogress('E');
#endif
/* Initialize onboard resources */
stm32_boardinitialize(); //stm32硬件板层配置初始化，完成，之后可以启动STM32的Nuttx操作系统
showprogress('F');
/* Then start NuttX */
showprogress('\r');
showprogress('\n');
#ifdef CONFIG_STACK_COLORATION
/* Set the IDLE stack to the coloration value and jump into os_start() */
go_os_start((FAR void *)&_ebss, CONFIG_IDLETHREAD_STACKSIZE);
#else
/* Call os_start() */
os_start(); //启动Nuttx操作系统
/* Shoulnd't get here */
for (; ; ); //进入死循环，这里是不是看到跟一般的FreeRTOS基本一样，就是配置硬件时钟，串口，IO等等，可以启动Nuttx操作系统，之后执行while死循环。
#endif
}（2）nuttx启动入口函数：void os_start(void)
/****************************************************************************
* Name: os_start
*
* Description:
* This function is called to initialize the operating system and to spawn
* the user initialization thread of execution. This is the initial entry
* point into NuttX
*
* Input Parameters:
* None
*
* Returned value:
* Does not return.
*
****************************************************************************/
//这个函数被调用来初始化操作系统并生成执行的用户初始化线程。这是NuttX最初的切入点。
void os_start(void)
{
#ifdef CONFIG_SMP
int cpu;
#else
# define cpu 0
#endif
int i;
sinfo("Entry\n");
/* Boot up is complete */
g_os_initstate = OSINIT_BOOT;
/* Initialize RTOS Data ***************************************************/
/* Initialize all task lists */
dq_init(&g_readytorun); //初始化各种状态的任务列表（置为null）
dq_init(&g_pendingtasks);
dq_init(&g_waitingforsemaphore);
#ifndef CONFIG_DISABLE_SIGNALS
dq_init(&g_waitingforsignal);
#endif
#ifndef CONFIG_DISABLE_MQUEUE
dq_init(&g_waitingformqnotfull);
dq_init(&g_waitingformqnotempty);
#endif
#ifdef CONFIG_PAGING
dq_init(&g_waitingforfill);
#endif
dq_init(&g_inactivetasks);
#if (defined(CONFIG_BUILD_PROTECTED) || defined(CONFIG_BUILD_KERNEL)) && \
defined(CONFIG_MM_KERNEL_HEAP)
sq_init(&g_delayed_kfree);
#endif
#ifndef CONFIG_BUILD_KERNEL
sq_init(&g_delayed_kufree);
#endif
#ifdef CONFIG_SMP
for (i = 0; i < CONFIG_SMP_NCPUS; i++)
{
dq_init(&g_assignedtasks[i]);
}
#endif
/* Initialize the logic that determine unique process IDs. */
g_lastpid = 0;
for (i = 0; i < CONFIG_MAX_TASKS; i++) //初始化唯一可以确定的元素--进程ID
{
g_pidhash[i].tcb = NULL;
g_pidhash[i].pid = INVALID_PROCESS_ID;
}
/* Initialize the IDLE task TCB *******************************************/
//初始化空闲任务TCB
#ifdef CONFIG_SMP
for (cpu = 0; cpu < CONFIG_SMP_NCPUS; cpu++, g_lastpid++)
#endif
{
FAR dq_queue_t *tasklist;
int hashndx;
/* Assign the process ID(s) of ZERO to the idle task(s) */
hashndx = PIDHASH(g_lastpid);
g_pidhash[hashndx].tcb = &g_idletcb[cpu].cmn;
g_pidhash[hashndx].pid = g_lastpid;
/* Initialize a TCB for this thread of execution. NOTE: The default
* value for most components of the g_idletcb are zero. The entire
* structure is set to zero. Then only the (potentially) non-zero
* elements are initialized. NOTE: The idle task is the only task in
* that has pid == 0 and sched_priority == 0.
*/
memset((void *)&g_idletcb[cpu], 0, sizeof(struct task_tcb_s));
g_idletcb[cpu].cmn.pid = g_lastpid;
g_idletcb[cpu].cmn.task_state = TSTATE_TASK_RUNNING;
/* Set the entry point. This is only for debug purposes. NOTE: that
* the start_t entry point is not saved. That is acceptable, however,
* becaue it can be used only for restarting a task: The IDLE task
* cannot be restarted.
*/
#ifdef CONFIG_SMP
if (cpu > 0)
{
g_idletcb[cpu].cmn.start = os_idle_trampoline;
g_idletcb[cpu].cmn.entry.main = os_idle_task;
}
else
#endif
{
g_idletcb[cpu].cmn.start = (start_t)os_start;
g_idletcb[cpu].cmn.entry.main = (main_t)os_start;
}
/* Set the task flags to indicate that this is a kernel thread and, if
* configured for SMP, that this task is locked to this CPU.
*/
#ifdef CONFIG_SMP
g_idletcb[cpu].cmn.flags = (TCB_FLAG_TTYPE_KERNEL | TCB_FLAG_NONCANCELABLE |
TCB_FLAG_CPU_LOCKED);
g_idletcb[cpu].cmn.cpu = cpu;
#else
g_idletcb[cpu].cmn.flags = (TCB_FLAG_TTYPE_KERNEL | TCB_FLAG_NONCANCELABLE);
#endif
#ifdef CONFIG_SMP
/* Set the affinity mask to allow the thread to run on all CPUs. No,
* this IDLE thread can only run on its assigned CPU. That is
* enforced by the TCB_FLAG_CPU_LOCKED which overrides the affinity
* mask. This is essential because all tasks inherit the affinity
* mask from their parent and, ultimately, the parent of all tasks is
* the IDLE task.
*/
g_idletcb[cpu].cmn.affinity = SCHED_ALL_CPUS;
#endif
#if CONFIG_TASK_NAME_SIZE > 0
/* Set the IDLE task name */
# ifdef CONFIG_SMP
snprintf(g_idletcb[cpu].cmn.name, CONFIG_TASK_NAME_SIZE, "CPU%d IDLE", cpu);
# else
strncpy(g_idletcb[cpu].cmn.name, g_idlename, CONFIG_TASK_NAME_SIZE);
g_idletcb[cpu].cmn.name[CONFIG_TASK_NAME_SIZE] = '\0';
# endif
#endif
/* Configure the task name in the argument list. The IDLE task does
* not really have an argument list, but this name is still useful
* for things like the NSH PS command.
*
* In the kernel mode build, the arguments are saved on the task's
* stack and there is no support that yet.
*/
#if CONFIG_TASK_NAME_SIZE > 0
g_idleargv[cpu][0] = g_idletcb[cpu].cmn.name;
#else
g_idleargv[cpu][0] = (FAR char *)g_idlename;
#endif /* CONFIG_TASK_NAME_SIZE */
g_idleargv[cpu][1] = NULL;
g_idletcb[cpu].argv = &g_idleargv[cpu][0];
/* Then add the idle task's TCB to the head of the corrent ready to
* run list.
*/
#ifdef CONFIG_SMP
tasklist = TLIST_HEAD(TSTATE_TASK_RUNNING, cpu);
#else
tasklist = TLIST_HEAD(TSTATE_TASK_RUNNING);
#endif
dq_addfirst((FAR dq_entry_t *)&g_idletcb[cpu], tasklist);
/* Initialize the processor-specific portion of the TCB */
up_initial_state(&g_idletcb[cpu].cmn);
}
/* Task lists are initialized */
g_os_initstate = OSINIT_TASKLISTS;
/* Initialize RTOS facilities *********************************************/
/* Initialize the semaphore facility. This has to be done very early
* because many subsystems depend upon fully functional semaphores.
*/
sem_initialize(); //初始化信号量
#if defined(MM_KERNEL_USRHEAP_INIT) || defined(CONFIG_MM_KERNEL_HEAP) || \
defined(CONFIG_MM_PGALLOC)
/* Initialize the memory manager */
{
FAR void *heap_start;
size_t heap_size;
#ifdef MM_KERNEL_USRHEAP_INIT
/* Get the user-mode heap from the platform specific code and configure
* the user-mode memory allocator.
*/
up_allocate_heap(&heap_start, &heap_size); //分配用户模式的堆（设置堆的起点和大小）
kumm_initialize(heap_start, heap_size); //初始化用户模式的堆
#endif
#ifdef CONFIG_MM_KERNEL_HEAP
/* Get the kernel-mode heap from the platform specific code and configure
* the kernel-mode memory allocator.
*/
up_allocate_kheap(&heap_start, &heap_size);
kmm_initialize(heap_start, heap_size);
#endif
#ifdef CONFIG_MM_PGALLOC
/* If there is a page allocator in the configuration, then get the page
* heap information from the platform-specific code and configure the
* page allocator.
*/
//如果在配置页面分配器，然后让页面堆信息从特定于平台的代码和配置页面分配器。
up_allocate_pgheap(&heap_start, &heap_size); //分配用户模式的堆（设置堆的起点和大小）
mm_pginitialize(heap_start, heap_size); //初始化内核模式的堆
#endif
}
#endif
/* The memory manager is available */
g_os_initstate = OSINIT_MEMORY;
#if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS)
/* Initialize tasking data structures */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (task_initialize != NULL)
#endif
{
task_initialize(); //初始化任务数据结构
}
#endif
/* Initialize the interrupt handling subsystem (if included) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (irq_initialize != NULL)
#endif
{
irq_initialize(); //初始化中断处理子系统（如果包含的话）
}
/* Initialize the watchdog facility (if included in the link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (wd_initialize != NULL)
#endif
{
wd_initialize(); //初始化看门狗设施（如果包含在链接中）
}
/* Initialize the POSIX timer facility (if included in the link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (clock_initialize != NULL)
#endif
{
clock_initialize(); //初始化POSIX定时器工具（如果包含在链接中）
}
#ifndef CONFIG_DISABLE_POSIX_TIMERS
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (timer_initialize != NULL)
#endif
{
timer_initialize(); //配置POSIX定时器
}
#endif
#ifndef CONFIG_DISABLE_SIGNALS
/* Initialize the signal facility (if in link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (sig_initialize != NULL)
#endif
{
sig_initialize();//初始化信号设施（如果在链路中）
}
#endif
#ifndef CONFIG_DISABLE_MQUEUE
/* Initialize the named message queue facility (if in link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (mq_initialize != NULL)
#endif
{
mq_initialize(); //初始化命名的消息队列设施（如果在链接中）
}
#endif
#ifndef CONFIG_DISABLE_PTHREAD
/* Initialize the thread-specific data facility (if in link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (pthread_initialize != NULL)
#endif
{
pthread_initialize(); //初始化线程特定的数据，空函数
}
#endif
#if CONFIG_NFILE_DESCRIPTORS > 0
/* Initialize the file system (needed to support device drivers) */
fs_initialize(); //初始化文件系统
#endif
#ifdef CONFIG_NET
/* Initialize the networking system. Network initialization is
* performed in two steps: (1) net_setup() initializes static
* configuration of the network support. This must be done prior
* to registering network drivers by up_initialize(). This step
* cannot require upon any hardware-depending features such as
* timers or interrupts.
*/
net_setup(); //初始化网络
#endif
/* The processor specific details of running the operating system
* will be handled here. Such things as setting up interrupt
* service routines and starting the clock are some of the things
* that are different for each processor and hardware platform.
*/
up_initialize(); //处理器特定的初始化
/* Hardware resources are available */
g_os_initstate = OSINIT_HARDWARE;
#ifdef CONFIG_NET
/* Complete initialization the networking system now that interrupts
* and timers have been configured by up_initialize().
*/
net_initialize();
#endif
#ifdef CONFIG_MM_SHM
/* Initialize shared memory support */
shm_initialize();
#endif
/* Initialize the C libraries. This is done last because the libraries
* may depend on the above.
*/
lib_initialize();
/* IDLE Group Initialization **********************************************/
/* Announce that the CPU0 IDLE task has started */
sched_note_start(&g_idletcb[0].cmn);
#ifdef CONFIG_SMP
/* Initialize the IDLE group for the IDLE task of each CPU */
for (cpu = 0; cpu < CONFIG_SMP_NCPUS; cpu++)
#endif
{
#ifdef HAVE_TASK_GROUP
/* Allocate the IDLE group */
DEBUGVERIFY(group_allocate(&g_idletcb[cpu], g_idletcb[cpu].cmn.flags));
#endif
#if CONFIG_NFILE_DESCRIPTORS > 0 || CONFIG_NSOCKET_DESCRIPTORS > 0
#ifdef CONFIG_SMP
if (cpu > 0)
{
/* Clone stdout, stderr, stdin from the CPU0 IDLE task. */
DEBUGVERIFY(group_setuptaskfiles(&g_idletcb[cpu]));
}
else
#endif
{
/* Create stdout, stderr, stdin on the CPU0 IDLE task. These
* will be inherited by all of the threads created by the CPU0
* IDLE task.
*/
DEBUGVERIFY(group_setupidlefiles(&g_idletcb[cpu]));
}
#endif
#ifdef HAVE_TASK_GROUP
/* Complete initialization of the IDLE group. Suppress retention
* of child status in the IDLE group.
*/
DEBUGVERIFY(group_initialize(&g_idletcb[cpu]));
g_idletcb[cpu].cmn.group->tg_flags = GROUP_FLAG_NOCLDWAIT;
#endif
}
/* Start SYSLOG ***********************************************************/
/* Late initialization of the system logging device. Some SYSLOG channel
* must be initialized late in the initialization sequence because it may
* depend on having IDLE task file structures setup.
*/
syslog_initialize(SYSLOG_INIT_LATE);
#ifdef CONFIG_SMP
/* Start all CPUs *********************************************************/
/* A few basic sanity checks */
DEBUGASSERT(this_cpu() == 0 && CONFIG_MAX_TASKS > CONFIG_SMP_NCPUS);
/* Take the memory manager semaphore on this CPU so that it will not be
* available on the other CPUs until we have finished initialization.
*/
DEBUGVERIFY(kmm_trysemaphore());
/* Then start the other CPUs */
DEBUGVERIFY(os_smp_start());//然后启动其他cpus
#endif /* CONFIG_SMP */
/* Bring Up the System ****************************************************/
/* The OS is fully initialized and we are beginning multi-tasking */
g_os_initstate = OSINIT_OSREADY;
/* Create initial tasks and bring-up the system */
DEBUGVERIFY(os_bringup()); //创建初始线程并提出系统
#ifdef CONFIG_SMP
/* Let other threads have access to the memory manager */
kmm_givesemaphore(); //让其他线程访问内存管理器
#endif /* CONFIG_SMP */
/* The IDLE Loop **********************************************************/
/* When control is return to this point, the system is idle. */
sinfo("CPU0: Beginning Idle Loop\n");
for (; ; )
{
/* Perform garbage collection (if it is not being done by the worker
* thread). This cleans-up memory de-allocations that were queued
* because they could not be freed in that execution context (for
* example, if the memory was freed from an interrupt handler).
*/
#ifndef CONFIG_SCHED_WORKQUEUE
/* We must have exclusive access to the memory manager to do this
* BUT the idle task cannot wait on a semaphore. So we only do
* the cleanup now if we can get the semaphore -- this should be
* possible because if the IDLE thread is running, no other task is!
*
* WARNING: This logic could have undesirable side-effects if priority
* inheritance is enabled. Imaginee the possible issues if the
* priority of the IDLE thread were to get boosted! Moral: If you
* use priority inheritance, then you should also enable the work
* queue so that is done in a safer context.
*/
if (sched_have_garbage() && kmm_trysemaphore() == 0)
{
sched_garbage_collection();
kmm_givesemaphore();
}
#endif
/* Perform any processor-specific idle state operations */
up_idle(); //执行任何处理器特定的空闲状态操作
}
}
（3）创建初始线程任务：os_bringup()
int os_bringup(void)
{
/* Setup up the initial environment for the idle task. At present, this
* may consist of only the initial PATH variable. The PATH variable is
* (probably) not used by the IDLE task. However, the environment
* containing the PATH variable will be inherited by all of the threads
* created by the IDLE task.
*/
//为空闲任务设置初始环境。目前，这可能只有初始路径变量。路径变量（可能）不被空闲任务使用。然而，包含路径变量，将所有的空闲任务创建线程继承的环境。
#if !defined(CONFIG_DISABLE_ENVIRON) && defined(CONFIG_PATH_INITIAL)
(void)setenv("PATH", CONFIG_PATH_INITIAL, 1);
#endif
/* Start the page fill worker kernel thread that will resolve page faults.
* This should always be the first thread started because it may have to
* resolve page faults in other threads
*/
//启动将解决页面错误的页面填充工作者内核线程。这应该总是第一个线程启动，因为它可能需要解决其他线程中的页面错误。
os_pgworker();
/* Start the worker thread that will serve as the device driver "bottom-
* half" and will perform misc garbage clean-up.
*/
//启动将充当设备驱动程序“下半部分”的工作线程，并执行MISC垃圾清理
os_workqueues();
/* Once the operating system has been initialized, the system must be
* started by spawning the user initialization thread of execution. This
* will be the first user-mode thread.
*/
//一旦操作系统被初始化，系统就必须通过生成执行的用户初始化线程来启动。这将是第一个用户模式线程。
os_start_application(); //这里是比较重要的函数
/* We an save a few bytes by discarding the IDLE thread's environment. */
#if !defined(CONFIG_DISABLE_ENVIRON) && defined(CONFIG_PATH_INITIAL)
(void)clearenv();
#endif
return OK;
}（4）创建初始线程任务：os_start_application()
static inline void os_start_application(void)
{
#ifdef CONFIG_BOARD_INITTHREAD
int pid;
/* Do the board/application initialization on a separate thread of
* execution.
*/
//在单独的执行线程上执行板/应用程序初始化。
//任务创建：名字，优先级，堆栈大小，任务函数入口
pid = kernel_thread("AppBringUp", CONFIG_BOARD_INITTHREAD_PRIORITY, //内核线程函数，
CONFIG_BOARD_INITTHREAD_STACKSIZE,
(main_t)os_start_task, (FAR char * const *)NULL);
ASSERT(pid > 0);
#else
/* Do the board/application initialization on this thread of execution. */
os_do_appstart();//在这个执行线程上执行板/应用程序初始化
#endif
}//分析下这个函数：kernel_thread（）
int kernel_thread(FAR const char *name, int priority,
int stack_size, main_t entry, FAR char *const argv[])
{
return thread_create(name, TCB_FLAG_TTYPE_KERNEL, priority, stack_size,
entry, argv);
}static int thread_create(FAR const char *name, uint8_t ttype, int priority,
int stack_size, main_t entry,
FAR char * const argv[])
{
FAR struct task_tcb_s *tcb;
pid_t pid;
int errcode;
int ret;
/* Allocate a TCB for the new task. */
tcb = (FAR struct task_tcb_s *)kmm_zalloc(sizeof(struct task_tcb_s));
if (!tcb)
{
serr("ERROR: Failed to allocate TCB\n");
errcode = ENOMEM;
goto errout;
}
/* Allocate a new task group with privileges appropriate for the parent
* thread type.
*/
#ifdef HAVE_TASK_GROUP
ret = group_allocate(tcb, ttype);
if (ret < 0)
{
errcode = -ret;
goto errout_with_tcb;
}
#endif
#if CONFIG_NFILE_DESCRIPTORS > 0 || CONFIG_NSOCKET_DESCRIPTORS > 0
#if 0 /* No... there are side effects */
/* Associate file descriptors with the new task. Exclude kernel threads;
* kernel threads do not have file or socket descriptors. They must use
* SYSLOG for output and the low-level psock interfaces for network I/O.
*/
if (ttype != TCB_FLAG_TTYPE_KERNEL)
#endif
{
ret = group_setuptaskfiles(tcb);
if (ret < OK)
{
errcode = -ret;
goto errout_with_tcb;
}
}
#endif
/* Allocate the stack for the TCB */
ret = up_create_stack((FAR struct tcb_s *)tcb, stack_size, ttype);
if (ret < OK)
{
errcode = -ret;
goto errout_with_tcb;
}
/* Initialize the task control block */
ret = task_schedsetup(tcb, priority, task_start, entry, ttype);
if (ret < OK)
{
errcode = -ret;
goto errout_with_tcb;
}
/* Setup to pass parameters to the new task */
(void)task_argsetup(tcb, name, argv);
/* Now we have enough in place that we can join the group */
#ifdef HAVE_TASK_GROUP
ret = group_initialize(tcb);
if (ret < 0)
{
errcode = -ret;
goto errout_with_tcb;
}
#endif
/* Get the assigned pid before we start the task */
pid = (int)tcb->cmn.pid;
/* Activate the task */
ret = task_activate((FAR struct tcb_s *)tcb);
if (ret < OK)
{
errcode = get_errno();
/* The TCB was added to the active task list by task_schedsetup() */
dq_rem((FAR dq_entry_t *)tcb, (FAR dq_queue_t *)&g_inactivetasks);
goto errout_with_tcb;
}
return pid;
errout_with_tcb:
sched_releasetcb((FAR struct tcb_s *)tcb, ttype);
errout:
set_errno(errcode);
return ERROR;
}
（5）创建初始线程任务：os_start_task()
#ifdef CONFIG_BOARD_INITTHREAD
static int os_start_task(int argc, FAR char **argv)
{
/* Do the board/application initialization and exit */
os_do_appstart(); //核心任务，这个将会调用FMU和IO的APP函数入口
return OK;
}
#endif#if defined(CONFIG_INIT_ENTRYPOINT)
static inline void os_do_appstart(void)
{
int pid;
#ifdef CONFIG_BOARD_INITIALIZE
/* Perform any last-minute, board-specific initialization, if so
* configured.
*/
board_initialize();
#endif
/* Start the application initialization task. In a flat build, this is
* entrypoint is given by the definitions, CONFIG_USER_ENTRYPOINT. In
* the protected build, however, we must get the address of the
* entrypoint from the header at the beginning of the user-space blob.
*/
sinfo("Starting init thread\n");
#ifdef CONFIG_BUILD_PROTECTED
DEBUGASSERT(USERSPACE->us_entrypoint != NULL);
pid = task_create("init", SCHED_PRIORITY_DEFAULT,
CONFIG_USERMAIN_STACKSIZE, USERSPACE->us_entrypoint,
(FAR char * const *)NULL);
#else
pid = task_create("init", SCHED_PRIORITY_DEFAULT, //优先级
CONFIG_USERMAIN_STACKSIZE, //堆栈大小
(main_t)CONFIG_USER_ENTRYPOINT, //函数入口
(FAR char * const *)NULL);
#endif
ASSERT(pid > 0);
}
#elif defined(CONFIG_INIT_FILEPATH)
static inline void os_do_appstart(void)
{
int ret;
#ifdef CONFIG_BOARD_INITIALIZE
/* Perform any last-minute, board-specific initialization, if so
* configured.
*/
board_initialize();
#endif
/* Start the application initialization program from a program in a
* mounted file system. Presumably the file system was mounted as part
* of the board_initialize() operation.
*/
sinfo("Starting init task: %s\n", CONFIG_USER_INITPATH);
ret = exec(CONFIG_USER_INITPATH, NULL, CONFIG_INIT_SYMTAB,
CONFIG_INIT_NEXPORTS);
ASSERT(ret >= 0);
}（6）核心接口CONFIG_USER_ENTRYPOINT
CONFIG_USER_ENTRYPOINT="nsh_main"//所在的目录
CONFIG_USER_ENTRYPOINT="user_start"//所在的目录
到这里需要分两路去研究，一路是STM32F427的nsh_main()函数，另外一路是user_start（）
（7）核心接口nsh_main（）函数
int nsh_main(int argc, char *argv[])
#endif
{
int exitval = 0;
int ret;
/* Call all C++ static constructors */
#if defined(CONFIG_EXAMPLES_NSH_CXXINITIALIZE)
up_cxxinitialize(); //调用C++静态构造函数
#endif
/* Make sure that we are using our symbol table */
#if defined(CONFIG_LIBC_EXECFUNCS) && defined(CONFIG_EXECFUNCS_SYMTAB)
exec_setsymtab(CONFIG_EXECFUNCS_SYMTAB, 0); //外部函数缺少定义
#endif
/* Register the BINFS file system */
#if defined(CONFIG_FS_BINFS) && (CONFIG_BUILTIN)
ret = builtin_initialize();
if (ret < 0)
{
fprintf(stderr, "ERROR: builtin_initialize failed: %d\n", ret);
exitval = 1;
}
#endif
/* Initialize the NSH library */
nsh_initialize(); //初始化NSH库
/* If the Telnet console is selected as a front-end, then start the
* Telnet daemon UNLESS network initialization is deferred via
* CONFIG_NSH_NETLOCAL. In that case, the telnet daemon must be
* started manually with the telnetd command after the network has
* been initialized
*/
#if defined(CONFIG_NSH_TELNET) && !defined(CONFIG_NSH_NETLOCAL)
ret = nsh_telnetstart(ADDR_FAMILY);
if (ret < 0)
{
/* The daemon is NOT running. Report the error then fail...
* either with the serial console up or just exiting.
*/
fprintf(stderr, "ERROR: Failed to start TELNET daemon: %d\n", ret);
exitval = 1;
}
#endif
/* If the serial console front end is selected, then run it on this thread */
#ifdef CONFIG_NSH_CONSOLE
ret = nsh_consolemain(0, NULL); //重要的函数
/* nsh_consolemain() should not return. So if we get here, something
* is wrong.
*/
#if CONFIG_NFILE_DESCRIPTORS > 0
fprintf(stderr, "ERROR: nsh_consolemain() returned: %d\n", ret);
#else
printf("ERROR: nsh_consolemain() returned: %d\n", ret);
#endif
exitval = 1;
#endif
return exitval;
}
（1）int nsh_consolemain(int argc, char *argv[])
int nsh_consolemain(int argc, char *argv[])
{
FAR struct console_stdio_s *pstate = nsh_newconsole();
int ret;
DEBUGASSERT(pstate != NULL);
#ifdef CONFIG_NSH_ROMFSETC
/* Execute the start-up script */
(void)nsh_initscript(&pstate->cn_vtbl); //执行脚本初始化
#ifndef CONFIG_NSH_DISABLESCRIPT
/* Reset the option flags */
pstate->cn_vtbl.np.np_flags = NSH_NP_SET_OPTIONS_INIT;
#endif
#endif
#ifdef CONFIG_NSH_USBDEV_TRACE
/* Initialize any USB tracing options that were requested */
usbtrace_enable(TRACE_BITSET);
#endif
/* Execute the session */
ret = nsh_session(pstate); //与用户交互的终端命令，我们用还是那个危机连接飞控时，可以与飞控交互的串口命令
/* Exit upon return */
nsh_exit(&pstate->cn_vtbl, ret);
return ret;
}
#endif /* !HAVE_USB_CONSOLE && !HAVE_USB_KEYBOARD */
（2） (void)nsh_initscript(&pstate->cn_vtbl);
int nsh_initscript(FAR struct nsh_vtbl_s *vtbl)
{
static bool initialized;
bool already;
int ret = OK;
/* Atomic test and set of the initialized flag */
sched_lock();
already = initialized;
initialized = true;
sched_unlock();
/* If we have not already executed the init script, then do so now */
if (!already)
{
ret = nsh_script(vtbl, "init", NSH_INITPATH); //解析脚本
}
return ret;
}（3）ret = nsh_script(vtbl, “init”, NSH_INITPATH); //解析脚本
#!nsh
# Un comment and use set +e to ignore and set -e to enable 'exit on error control'
set +e
# Un comment the line below to help debug scripts by printing a trace of the script commands
#set -x
# PX4FMU startup script.
#
# NOTE: environment variable references:
# If the dollar sign ('$') is followed by a left bracket ('{') then the
# variable name is terminated with the right bracket character ('}').
# Otherwise, the variable name goes to the end of the argument.
#
#
# NOTE: COMMENT LINES ARE REMOVED BEFORE STORED IN ROMFS.
#
# UART mapping on FMUv2/3/4:
#
# UART1 /dev/ttyS0 IO debug
# USART2 /dev/ttyS1 TELEM1 (flow control)
# USART3 /dev/ttyS2 TELEM2 (flow control)
# UART4
# UART7 CONSOLE
# UART8 SERIAL4
#
#
# UART mapping on FMUv5:
#
# UART1 /dev/ttyS0 GPS
# USART2 /dev/ttyS1 TELEM1 (flow control)
# USART3 /dev/ttyS2 TELEM2 (flow control)
# UART4 /dev/ttyS3 ?
# USART6 /dev/ttyS4 TELEM3 (flow control)
# UART7 /dev/ttyS5 ?
# UART8 /dev/ttyS6 CONSOLE
#
# Mount the procfs.
#
mount -t procfs /proc
#
# Start CDC/ACM serial driver
#
sercon
# print full system version
ver all
#
# Default to auto-start mode.
#
set MODE autostart
set TUNE_ERR ML<<CP4CP4CP4CP4CP4
set LOG_FILE /fs/microsd/bootlog.txt
#
# Try to mount the microSD card.
#
# REBOOTWORK this needs to start after the flight control loop
if mount -t vfat /dev/mmcsd0 /fs/microsd
then
echo "[i] microSD mounted: /fs/microsd"
if hardfault_log check
then
tone_alarm error
if hardfault_log commit
then
hardfault_log reset
tone_alarm stop
fi
else
# Start playing the startup tune
tone_alarm start
fi
else
tone_alarm MBAGP
if mkfatfs /dev/mmcsd0
then
if mount -t vfat /dev/mmcsd0 /fs/microsd
then
echo "INFO [init] MicroSD card formatted"
else
echo "ERROR [init] Format failed"
tone_alarm MNBG
set LOG_FILE /dev/null
fi
else
set LOG_FILE /dev/null
fi
fi
#
# Look for an init script on the microSD card.
# Disable autostart if the script found.
#
set FRC /fs/microsd/etc/rc.txt
if [ -f $FRC ]
then
echo "INFO [init] Executing script: ${FRC}"
sh $FRC
set MODE custom
fi
unset FRC
if [ $MODE == autostart ]
then
#
# Start the ORB (first app to start)
#
uorb start
#
# Load parameters
#
set PARAM_FILE /fs/microsd/params
if mtd start
then
set PARAM_FILE /fs/mtd_params
fi
param select $PARAM_FILE
if param load
then
else
if param reset
then
fi
fi
#
# Start system state indicator
#
if rgbled start
then
else
if blinkm start
then
blinkm systemstate
fi
fi
# FMUv5 may have both PWM I2C RGB LED support
rgbled_pwm start
#
# Set AUTOCNF flag to use it in AUTOSTART scripts
#
if param compare SYS_AUTOCONFIG 1
then
# Wipe out params except RC* and total flight time
param reset_nostart RC* LND_FLIGHT_T_*
set AUTOCNF yes
else
set AUTOCNF no
#
# Release 1.4.0 transitional support:
# set to old default if unconfigured.
# this preserves the previous behaviour
#
if param compare BAT_N_CELLS 0
then
param set BAT_N_CELLS 3
fi
fi
#
# Set default values
#
set VEHICLE_TYPE none
set MIXER none
set MIXER_AUX none
set OUTPUT_MODE none
set PWM_OUT none
set PWM_RATE p:PWM_RATE
set PWM_DISARMED p:PWM_DISARMED
set PWM_MIN p:PWM_MIN
set PWM_MAX p:PWM_MAX
set PWM_AUX_OUT none
set PWM_AUX_RATE none
set PWM_ACHDIS none
set PWM_AUX_DISARMED p:PWM_AUX_DISARMED
set PWM_AUX_MIN p:PWM_AUX_MIN
set PWM_AUX_MAX p:PWM_AUX_MAX
set FAILSAFE_AUX none
set MK_MODE none
set FMU_MODE pwm
set AUX_MODE pwm
set FMU_ARGS ""
set MAVLINK_F default
set MAVLINK_COMPANION_DEVICE /dev/ttyS2
set MAV_TYPE none
set FAILSAFE none
set USE_IO no
set LOGGER_BUF 16
if ver hwcmp PX4FMU_V4
then
param set SYS_FMU_TASK 1
fi
if ver hwcmp PX4FMU_V4PRO
then
param set SYS_FMU_TASK 1
fi
if ver hwcmp PX4FMU_V5
then
param set SYS_FMU_TASK 1
set MAVLINK_COMPANION_DEVICE /dev/ttyS3
set LOGGER_BUF 64
param set SDLOG_MODE 2
fi
if ver hwcmp CRAZYFLIE
then
if param compare SYS_AUTOSTART 0
then
param set SYS_AUTOSTART 4900
set AUTOCNF yes
fi
fi
if ver hwcmp AEROFC_V1
then
if param compare SYS_AUTOSTART 0
then
set AUTOCNF yes
fi
# We don't allow changing AUTOSTART as it doesn't work in
# other configurations
param set SYS_AUTOSTART 4070
fi
if ver hwcmp NXPHLITE_V3
then
param set SYS_FMU_TASK 1
set MAVLINK_COMPANION_DEVICE /dev/ttyS4
fi
#
# Set USE_IO flag
#
if param compare SYS_USE_IO 1
then
set USE_IO yes
fi
if param compare SYS_FMU_TASK 1
then
set FMU_ARGS "-t"
fi
#
# Set parameters and env variables for selected AUTOSTART
#
if param compare SYS_AUTOSTART 0
then
else
sh /etc/init.d/rc.autostart
fi
unset MODE
#
# If mount (gimbal) control is enabled and output mode is AUX, set the aux
# mixer to mount (override the airframe-specific MIXER_AUX setting)
#
if param compare MNT_MODE_IN -1
then
else
if param compare MNT_MODE_OUT 0
then
set MIXER_AUX mount
fi
fi
#
# Override parameters from user configuration file
#
set FCONFIG /fs/microsd/etc/config.txt
if [ -f $FCONFIG ]
then
echo "Custom: ${FCONFIG}"
sh $FCONFIG
fi
unset FCONFIG
#
# If autoconfig parameter was set, reset it and save parameters
#
if [ $AUTOCNF == yes ]
then
# Disable safety switch by default on Pixracer
if ver hwcmp PX4FMU_V4
then
param set CBRK_IO_SAFETY 22027
fi
param set SYS_AUTOCONFIG 0
fi
unset AUTOCNF
set IO_PRESENT no
if [ $USE_IO == yes ]
then
#
# Check if PX4IO present and update firmware if needed
#
if [ -f /etc/extras/px4io-v2.bin ]
then
set IO_FILE /etc/extras/px4io-v2.bin
if px4io checkcrc ${IO_FILE}
then
echo "[init] PX4IO CRC OK" >> $LOG_FILE
set IO_PRESENT yes
else
tone_alarm MLL32CP8MB
if px4io start
then
# try to safe px4 io so motor outputs dont go crazy
if px4io safety_on
then
# success! no-op
else
# px4io did not respond to the safety command
px4io stop
fi
fi
if px4io forceupdate 14662 ${IO_FILE}
then
usleep 10000
if px4io checkcrc ${IO_FILE}
then
echo "PX4IO CRC OK after updating" >> $LOG_FILE
tone_alarm MLL8CDE
set IO_PRESENT yes
else
echo "PX4IO update failed" >> $LOG_FILE
tone_alarm ${TUNE_ERR}
fi
else
echo "PX4IO update failed" >> $LOG_FILE
tone_alarm ${TUNE_ERR}
fi
fi
fi
unset IO_FILE
if [ $IO_PRESENT == no ]
then
echo "PX4IO not found" >> $LOG_FILE
tone_alarm ${TUNE_ERR}
fi
fi
#
# Set default output if not set
#
if [ $OUTPUT_MODE == none ]
then
if [ $USE_IO == yes ]
then
set OUTPUT_MODE io
else
set OUTPUT_MODE fmu
fi
fi
if [ $OUTPUT_MODE == io -a $IO_PRESENT != yes ]
then
# Need IO for output but it not present, disable output
set OUTPUT_MODE none
fi
if [ $OUTPUT_MODE == tap_esc ]
then
set FMU_MODE rcin
fi
set DATAMAN_OPT ""
if ver hwcmp AEROFC_V1
then
set DATAMAN_OPT -i
fi
if ver hwcmp AEROCORE2
then
set DATAMAN_OPT "-f /fs/mtd_dataman"
fi
# waypoint storage
# REBOOTWORK this needs to start in parallel
if dataman start $DATAMAN_OPT
then
fi
unset DATAMAN_OPT
#
# Sensors System (start before Commander so Preflight checks are properly run)
# commander Needs to be this early for in-air-restarts
if param compare SYS_HITL 1
then
set OUTPUT_MODE hil
sensors start -h
commander start --hil
else
if ver hwcmp PX4_SAME70XPLAINED_V1
then
gps start -d /dev/ttyS2
else
gps start
fi
sh /etc/init.d/rc.sensors
commander start
fi
send_event start
load_mon start
#
# Check if UAVCAN is enabled, default to it for ESCs
#
if param greater UAVCAN_ENABLE 2
then
set OUTPUT_MODE uavcan_esc
fi
# Sensors on the PWM interface bank
if param compare SENS_EN_LL40LS 1
then
# clear pins 5 and 6
set FMU_MODE pwm4
set AUX_MODE pwm4
fi
if param greater TRIG_MODE 0
then
# We ONLY support trigger on pins 5 and 6 when simultanously using AUX for actuator output
if param compare TRIG_PINS 56
then
# clear pins 5 and 6
set FMU_MODE pwm4
set AUX_MODE pwm4
else
set FMU_MODE none
set AUX_MODE none
fi
camera_trigger start
param set CAM_FBACK_MODE 1
camera_feedback start
fi
# If OUTPUT_MODE == none then something is wrong with setup and we shouldn't try to enable output
if [ $OUTPUT_MODE != none ]
then
if [ $OUTPUT_MODE == uavcan_esc ]
then
if param compare UAVCAN_ENABLE 0
then
echo "OVERRIDING UAVCAN_ENABLE = 3" >> $LOG_FILE
param set UAVCAN_ENABLE 3
fi
fi
if [ $OUTPUT_MODE == io -o $OUTPUT_MODE == uavcan_esc ]
then
if px4io start
then
sh /etc/init.d/rc.io
else
echo "PX4IO start failed" >> $LOG_FILE
tone_alarm $TUNE_ERR
fi
fi
if [ $OUTPUT_MODE == fmu ]
then
if fmu mode_$FMU_MODE $FMU_ARGS
then
else
echo "FMU start failed" >> $LOG_FILE
tone_alarm $TUNE_ERR
fi
fi
if [ $OUTPUT_MODE == mkblctrl ]
then
set MKBLCTRL_ARG ""
if [ $MKBLCTRL_MODE == x ]
then
set MKBLCTRL_ARG "-mkmode x"
fi
if [ $MKBLCTRL_MODE == + ]
then
set MKBLCTRL_ARG "-mkmode +"
fi
if mkblctrl $MKBLCTRL_ARG
then
else
echo "MK start failed" >> $LOG_FILE
tone_alarm $TUNE_ERR
fi
unset MKBLCTRL_ARG
fi
unset MK_MODE
if [ $OUTPUT_MODE == hil ]
then
if pwm_out_sim mode_pwm16
then
else
tone_alarm $TUNE_ERR
fi
fi
#
# Start IO or FMU for RC PPM input if needed
#
if [ $IO_PRESENT == yes ]
then
if [ $OUTPUT_MODE != io ]
then
if px4io start
then
sh /etc/init.d/rc.io
else
echo "PX4IO start failed" >> $LOG_FILE
tone_alarm $TUNE_ERR
fi
fi
else
if [ $OUTPUT_MODE != fmu ]
then
if fmu mode_${FMU_MODE} $FMU_ARGS
then
else
echo "FMU mode_${FMU_MODE} start failed" >> $LOG_FILE
tone_alarm $TUNE_ERR
fi
fi
fi
fi
if [ $MAVLINK_F == default ]
then
# Normal mode, use baudrate 57600 (default) and data rate 1000 bytes/s
set MAVLINK_F "-r 1200 -f"
# Avoid using ttyS1 for MAVLink on FMUv4
if ver hwcmp PX4FMU_V4
then
set MAVLINK_F "-r 1200 -d /dev/ttyS1"
# Start MAVLink on Wifi (ESP8266 port)
mavlink start -r 20000 -b 921600 -d /dev/ttyS0
fi
if ver hwcmp AEROFC_V1
then
set MAVLINK_F "-r 1200 -d /dev/ttyS3"
fi
if ver hwcmp CRAZYFLIE
then
# Avoid using either of the two available serials
set MAVLINK_F none
fi
fi
if [ "x$MAVLINK_F" == xnone ]
then
else
mavlink start ${MAVLINK_F}
fi
unset MAVLINK_F
#
# MAVLink onboard / TELEM2
#
# XXX We need a better way for runtime eval of shell variables,
# but this works for now
if param compare SYS_COMPANION 10
then
frsky_telemetry start -d ${MAVLINK_COMPANION_DEVICE}
fi
if param compare SYS_COMPANION 20
then
syslink start
mavlink start -d /dev/bridge0 -b 57600 -m osd -r 40000
fi
if param compare SYS_COMPANION 921600
then
if ver hwcmp AEROFC_V1
then
if protocol_splitter start ${MAVLINK_COMPANION_DEVICE}
then
mavlink start -d /dev/mavlink -b 921600 -m onboard -r 5000 -x
micrortps_client start -d /dev/rtps -b 921600 -l -1 -s 2000
else
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 921600 -m onboard -r 80000 -x -f
fi
else
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 921600 -m onboard -r 80000 -x -f
fi
fi
if param compare SYS_COMPANION 57600
then
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 57600 -m onboard -r 5000 -x -f
fi
if param compare SYS_COMPANION 460800
then
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 460800 -m onboard -r 5000 -x -f
fi
if param compare SYS_COMPANION 157600
then
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 57600 -m osd -r 1000
fi
if param compare SYS_COMPANION 257600
then
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 57600 -m magic -r 5000 -x -f
fi
if param compare SYS_COMPANION 319200
then
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 19200 -r 1000 -f
fi
if param compare SYS_COMPANION 338400
then
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 38400 -r 1000 -f
fi
if param compare SYS_COMPANION 357600
then
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 57600 -r 1000 -f
fi
if param compare SYS_COMPANION 3115200
then
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 115200 -r 1000 -f
fi
if param compare SYS_COMPANION 419200
then
iridiumsbd start -d /dev/ttyS2
mavlink start -d /dev/iridium -b 19200 -m iridium -r 10
fi
if param compare SYS_COMPANION 1921600
then
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 921600 -r 20000
fi
if param compare SYS_COMPANION 1500000
then
mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 1500000 -m onboard -r 10000 -x -f
fi
unset MAVLINK_COMPANION_DEVICE
#
# Starting stuff according to UAVCAN_ENABLE value
#
if param greater UAVCAN_ENABLE 0
then
if uavcan start
then
set LOGGER_BUF 6
uavcan start fw
else
tone_alarm ${TUNE_ERR}
fi
fi
if ver hwcmp PX4FMU_V4
then
frsky_telemetry start -d /dev/ttyS6
fi
if ver hwcmp MINDPX_V2
then
frsky_telemetry start -d /dev/ttyS6
fi
if ver hwcmp PX4FMU_V2
then
# Check for flow sensor - as it is a background task, launch it last
px4flow start &
fi
if ver hwcmp PX4FMU_V4
then
# Check for flow sensor - as it is a background task, launch it last
px4flow start &
fi
if ver hwcmp PX4FMU_V4PRO
then
# Check for flow sensor - as it is a background task, launch it last
px4flow start &
fi
if ver hwcmp MINDPX_V2
then
px4flow start &
fi
if ver hwcmp AEROFC_V1
then
# don't start mavlink ttyACM0 on aerofc_v1
else
# Start MAVLink
mavlink start -r 800000 -d /dev/ttyACM0 -m config -x
fi
#
# Logging
#
if param compare SYS_LOGGER 0
then
sdlog2 start -r 100 -a -b 9 -t
else
set LOGGER_ARGS ""
if param compare SDLOG_MODE 1
then
set LOGGER_ARGS "-e"
fi
if param compare SDLOG_MODE 2
then
set LOGGER_ARGS "-f"
fi
if ver hwcmp AEROFC_V1
then
set LOGGER_ARGS "-m mavlink"
fi
logger start -b ${LOGGER_BUF} -t ${LOGGER_ARGS}
unset LOGGER_BUF
unset LOGGER_ARGS
fi
#
# Fixed wing setup
#
if [ $VEHICLE_TYPE == fw ]
then
if [ $MIXER == none ]
then
# Set default mixer for fixed wing if not defined
set MIXER AERT
fi
if [ $MAV_TYPE == none ]
then
# Use MAV_TYPE = 1 (fixed wing) if not defined
set MAV_TYPE 1
fi
param set MAV_TYPE ${MAV_TYPE}
# Load mixer and configure outputs
sh /etc/init.d/rc.interface
# Start standard fixedwing apps
sh /etc/init.d/rc.fw_apps
fi
#
# Multicopters setup
#
if [ $VEHICLE_TYPE == mc ]
then
if [ $MIXER == none ]
then
echo "Mixer undefined"
fi
if [ $MAV_TYPE == none ]
then
# Use mixer to detect vehicle type
if [ $MIXER == quad_x -o $MIXER == quad_+ ]
then
set MAV_TYPE 2
fi
if [ $MIXER == quad_w -o $MIXER == quad_dc ]
then
set MAV_TYPE 2
fi
if [ $MIXER == quad_h ]
then
set MAV_TYPE 2
fi
if [ $MIXER == tri_y_yaw- -o $MIXER == tri_y_yaw+ ]
then
set MAV_TYPE 15
fi
if [ $MIXER == hexa_x -o $MIXER == hexa_+ ]
then
set MAV_TYPE 13
fi
if [ $MIXER == hexa_cox ]
then
set MAV_TYPE 13
fi
if [ $MIXER == octo_x -o $MIXER == octo_+ ]
then
set MAV_TYPE 14
fi
if [ $MIXER == octo_cox -o $MIXER == octo_cox_w ]
then
set MAV_TYPE 14
fi
if [ $MIXER == coax ]
then
set MAV_TYPE 3
fi
fi
# Still no MAV_TYPE found
if [ $MAV_TYPE == none ]
then
echo "Unknown MAV_TYPE"
param set MAV_TYPE 2
else
param set MAV_TYPE ${MAV_TYPE}
fi
# Load mixer and configure outputs
sh /etc/init.d/rc.interface
# Start standard multicopter apps
sh /etc/init.d/rc.mc_apps
fi
#
# VTOL setup
#
if [ $VEHICLE_TYPE == vtol ]
then
if [ $MIXER == none ]
then
echo "VTOL mixer undefined"
fi
if [ $MAV_TYPE == none ]
then
# Use mixer to detect vehicle type
if [ $MIXER == caipirinha_vtol ]
then
set MAV_TYPE 19
fi
if [ $MIXER == firefly6 ]
then
set MAV_TYPE 21
fi
if [ $MIXER == quad_x_pusher_vtol ]
then
set MAV_TYPE 22
fi
fi
# Still no MAV_TYPE found
if [ $MAV_TYPE == none ]
then
echo "Unknown MAV_TYPE"
param set MAV_TYPE 19
else
param set MAV_TYPE ${MAV_TYPE}
fi
# Load mixer and configure outputs
sh /etc/init.d/rc.interface
# Start standard vtol apps
sh /etc/init.d/rc.vtol_apps
fi
#
# UGV setup
#
if [ $VEHICLE_TYPE == ugv ]
then
if [ $MIXER == none ]
then
# Set default mixer for UGV if not defined
set MIXER ugv_generic
fi
if [ $MAV_TYPE == none ]
then
# Use MAV_TYPE = 10 (UGV) if not defined
set MAV_TYPE 10
fi
param set MAV_TYPE ${MAV_TYPE}
# Load mixer and configure outputs
sh /etc/init.d/rc.interface
# Start standard UGV apps
sh /etc/init.d/rc.ugv_apps
fi
#
# For snapdragon, we need a passthrough mode
# Do not run any mavlink instances since we need the serial port for
# communication with Snapdragon.
#
if [ $VEHICLE_TYPE == passthrough ]
then
mavlink stop-all
commander stop
# Stop multicopter attitude controller if it is running, the controls come
# from Snapdragon.
if mc_att_control stop
then
fi
# Start snapdragon interface on serial port.
if ver hwcmp PX4FMU_V2
then
# On Pixfalcon use the standard telemetry port (Telem 1).
snapdragon_rc_pwm start -d /dev/ttyS1
px4io start
fi
if ver hwcmp PX4FMU_V4
then
# On Pixracer use Telem 2 port (TL2).
snapdragon_rc_pwm start -d /dev/ttyS2
fmu mode_pwm4 $FMU_ARGS
fi
pwm failsafe -c 1234 -p 900
pwm disarmed -c 1234 -p 900
# Arm straightaway.
pwm arm
# Use 400 Hz PWM on all channels.
pwm rate -a -r 400
fi
unset MIXER
unset MAV_TYPE
unset OUTPUT_MODE
#
# Start the navigator
#
navigator start
#
# Generic setup (autostart ID not found)
#
if [ $VEHICLE_TYPE == none ]
then
echo "No autostart ID found"
ekf2 start
fi
# Start any custom addons
set FEXTRAS /fs/microsd/etc/extras.txt
if [ -f $FEXTRAS ]
then
echo "Addons script: ${FEXTRAS}"
sh $FEXTRAS
fi
unset FEXTRAS
if ver hwcmp CRAZYFLIE
then
# CF2 shouldn't have an sd card
else
if ver hwcmp AEROCORE2
then
# AEROCORE2 shouldn't have an sd card
else
# Run no SD alarm
if [ $LOG_FILE == /dev/null ]
then
# Play SOS
tone_alarm error
fi
fi
fi
#
# Check if we should start a thermal calibration
# TODO move further up and don't start unnecessary services if we are calibrating
#
set TEMP_CALIB_ARGS ""
if param compare SYS_CAL_GYRO 1
then
set TEMP_CALIB_ARGS "${TEMP_CALIB_ARGS} -g"
param set SYS_CAL_GYRO 0
fi
if param compare SYS_CAL_ACCEL 1
then
set TEMP_CALIB_ARGS "${TEMP_CALIB_ARGS} -a"
param set SYS_CAL_ACCEL 0
fi
if param compare SYS_CAL_BARO 1
then
set TEMP_CALIB_ARGS "${TEMP_CALIB_ARGS} -b"
param set SYS_CAL_BARO 0
fi
if [ "x$TEMP_CALIB_ARGS" != "x" ]
then
send_event temperature_calibration ${TEMP_CALIB_ARGS}
fi
unset TEMP_CALIB_ARGS
# vmount to control mounts such as gimbals, disabled by default.
if param compare MNT_MODE_IN -1
then
else
if vmount start
then
fi
fi
# End of autostart
fi
# There is no further script processing, so we can free some RAM
# XXX potentially unset all script variables.
unset TUNE_ERR
# Boot is complete, inform MAVLink app(s) that the system is now fully up and running
mavlink boot_complete
int nsh_script(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
FAR const char *path)
{
FAR char *fullpath;
FAR FILE *savestream;
FAR char *buffer;
FAR char *pret;
int ret = ERROR;
/* The path to the script may be relative to the current working directory */
fullpath = nsh_getfullpath(vtbl, path);
if (!fullpath)
{
return ERROR;
}
/* Get a reference to the common input buffer */
buffer = nsh_linebuffer(vtbl);
if (buffer)
{
/* Save the parent stream in case of nested script processing */
savestream = vtbl->np.np_stream;
/* Open the file containing the script */
vtbl->np.np_stream = fopen(fullpath, "r");
if (!vtbl->np.np_stream)
{
nsh_output(vtbl, g_fmtcmdfailed, cmd, "fopen", NSH_ERRNO);
/* Free the allocated path */
nsh_freefullpath(fullpath);
/* Restore the parent script stream */
vtbl->np.np_stream = savestream;
return ERROR;
}
/* Loop, processing each command line in the script file (or
* until an error occurs)
*/
do
{
/* Flush any output generated by the previous line */
fflush(stdout);
#ifndef CONFIG_NSH_DISABLE_LOOPS
/* Get the current file position. This is used to control
* looping. If a loop begins in the next line, then this file
* offset will be needed to locate the top of the loop in the
* script file. Note that ftell will return -1 on failure.
*/
vtbl->np.np_foffs = ftell(vtbl->np.np_stream);
vtbl->np.np_loffs = 0;
if (vtbl->np.np_foffs < 0)
{
nsh_output(vtbl, g_fmtcmdfailed, "loop", "ftell", NSH_ERRNO);
}
#endif
/* Now read the next line from the script file */
pret = fgets(buffer, CONFIG_NSH_LINELEN, vtbl->np.np_stream);
if (pret)
{
/* Parse process the command. NOTE: this is recursive...
* we got to cmd_sh via a call to nsh_parse. So some
* considerable amount of stack may be used.
*/
if ((vtbl->np.np_flags & NSH_PFLAG_SILENT) == 0)
{
nsh_output(vtbl,"%s", buffer);
}
ret = nsh_parse(vtbl, buffer);
}
}
while (pret && (ret == OK || (vtbl->np.np_flags & NSH_PFLAG_IGNORE)));
/* Close the script file */
fclose(vtbl->np.np_stream);
/* Restore the parent script stream */
vtbl->np.np_stream = savestream;
}
/* Free the allocated path */
nsh_freefullpath(fullpath);
return ret;
}（8）核心接口user_start（）函数
//所在的目录
可以看出IO只是FMU的一个核心模块。所以FMU与IO怎么启动的过程是我们需要核心研究的
int user_start(int argc, char *argv[])
{
/* configure the first 8 PWM outputs (i.e. all of them) */
up_pwm_servo_init(0xff); //配置8路PWM输出
#if defined(CONFIG_HAVE_CXX) && defined(CONFIG_HAVE_CXXINITIALIZE)
/* run C++ ctors before we go any further */
up_cxxinitialize(); //运行C++库
# if defined(CONFIG_EXAMPLES_NSH_CXXINITIALIZE)
# error CONFIG_EXAMPLES_NSH_CXXINITIALIZE Must not be defined! Use CONFIG_HAVE_CXX and CONFIG_HAVE_CXXINITIALIZE.
# endif
#else
# error platform is dependent on c++ both CONFIG_HAVE_CXX and CONFIG_HAVE_CXXINITIALIZE must be defined.
#endif
/* reset all to zero */
memset(&system_state, 0, sizeof(system_state));//复位系统存储
/* configure the high-resolution time/callout interface */
hrt_init(); //配置高速时钟
/* calculate our fw CRC so FMU can decide if we need to update */
calculate_fw_crc(); //计算我用的crc时钟，判断fmu是否更新
/*
* Poll at 1ms intervals for received bytes that have not triggered
* a DMA event.对于未触发的接收字节，以1ms间隔进行轮询
*/
#ifdef CONFIG_ARCH_DMA
hrt_call_every(&serial_dma_call, 1000, 1000, (hrt_callout)stm32_serial_dma_poll, NULL);
#endif
/* print some startup info */
syslog(LOG_INFO, "\nPX4IO: starting\n");
/* default all the LEDs to off while we start */
LED_AMBER(false); //关闭所有的灯
LED_BLUE(false);
LED_SAFETY(false);
#ifdef GPIO_LED4
LED_RING(false);
#endif
/* turn on servo power (if supported) */
#ifdef POWER_SERVO
POWER_SERVO(true); //打开servo电源
#endif
/* turn off S.Bus out (if supported) */
#ifdef ENABLE_SBUS_OUT
ENABLE_SBUS_OUT(false); //关闭SBUS
#endif
/* start the safety switch handler */
safety_init(); //启动安全开关处理器
/* initialise the control inputs */
controls_init(); //初始化控制输入
/* set up the ADC */
adc_init(); //初始化ADC
/* start the FMU interface */
interface_init();//串口初始化
/* add a performance counter for mixing */
perf_counter_t mixer_perf = perf_alloc(PC_ELAPSED, "mix"); //添加用于混合的性能计数器
/* add a performance counter for controls */
perf_counter_t controls_perf = perf_alloc(PC_ELAPSED, "controls");//为控件添加性能计数器
/* and one for measuring the loop rate */
perf_counter_t loop_perf = perf_alloc(PC_INTERVAL, "loop"); //一种测量环路速率的方法
struct mallinfo minfo = mallinfo();
r_page_status[PX4IO_P_STATUS_FREEMEM] = minfo.mxordblk;
syslog(LOG_INFO, "MEM: free %u, largest %u\n", minfo.mxordblk, minfo.fordblks);
/* initialize PWM limit lib */
pwm_limit_init(&pwm_limit); //初始化PWM限制
/*
* P O L I C E L I G H T S
*
* Not enough memory, lock down.
*
* We might need to allocate mixers later, and this will
* ensure that a developer doing a change will notice
* that he just burned the remaining RAM with static
* allocations. We don't want him to be able to
* get past that point. This needs to be clearly
* documented in the dev guide.
*
*/
if (minfo.mxordblk < 600)
{
syslog(LOG_ERR, "ERR: not enough MEM");
bool phase = false;
while (true)
{
if (phase)
{
LED_AMBER(true);
LED_BLUE(false);
} else
{
LED_AMBER(false);
LED_BLUE(true);
}
up_udelay(250000);
phase = !phase;
}
}
/* Start the failsafe led init */
failsafe_led_init();//启动故障安全LED初始化
/*
* Run everything in a tight loop.把每件事都搞得一团糟
*/
uint64_t last_debug_time = 0;
uint64_t last_heartbeat_time = 0;
uint64_t last_loop_time = 0;
for (;;)
{
dt = (hrt_absolute_time() - last_loop_time) / 1000000.0f;
last_loop_time = hrt_absolute_time();
if (dt < 0.0001f)
{
dt = 0.0001f;
} else if (dt > 0.02f)
{
dt = 0.02f;
}
/* track the rate at which the loop is running */
perf_count(loop_perf);//计算循环运行时间
/* kick the mixer */
perf_begin(mixer_perf);
mixer_tick();
perf_end(mixer_perf);
/* kick the control inputs */
perf_begin(controls_perf);
controls_tick();
perf_end(controls_perf);
/* some boards such as Pixhawk 2.1 made
the unfortunate choice to combine the blue led channel with
the IMU heater. We need a software hack to fix the hardware hack
by allowing to disable the LED / heater.
*/
if (r_page_setup[PX4IO_P_SETUP_THERMAL] == PX4IO_THERMAL_IGNORE) {
/*
blink blue LED at 4Hz in normal operation. When in
override blink 4x faster so the user can clearly see
that override is happening. This helps when
pre-flight testing the override system
*/
uint32_t heartbeat_period_us = 250 * 1000UL;
if (r_status_flags & PX4IO_P_STATUS_FLAGS_OVERRIDE) {
heartbeat_period_us /= 4;
}
if ((hrt_absolute_time() - last_heartbeat_time) > heartbeat_period_us) {
last_heartbeat_time = hrt_absolute_time();
heartbeat_blink();
}
} else if (r_page_setup[PX4IO_P_SETUP_THERMAL] < PX4IO_THERMAL_FULL) {
/* switch resistive heater off */
LED_BLUE(false);
} else {
/* switch resistive heater hard on */
LED_BLUE(true);
}
update_mem_usage();
ring_blink();
check_reboot();
/* check for debug activity (default: none) */
show_debug_messages();
/* post debug state at ~1Hz - this is via an auxiliary serial port
* DEFAULTS TO OFF!
*/
if (hrt_absolute_time() - last_debug_time > (1000 * 1000)) {
isr_debug(1, "d:%u s=0x%x a=0x%x f=0x%x m=%u",
(unsigned)r_page_setup[PX4IO_P_SETUP_SET_DEBUG],
(unsigned)r_status_flags,
(unsigned)r_setup_arming,
(unsigned)r_setup_features,
(unsigned)mallinfo().mxordblk);
last_debug_time = hrt_absolute_time();
}
}
}
可以看出px4所有的任务都是以任务函数执行，都在那个rcs里面，然而apm的不是这样
PX4的运行过程就先说到这里，后面会继续研究每个函数的作用，这里只是大致梳理一下过程。与APM形成比较
2.APM固件启动过程
(1)void __start(void)
void __start(void)
{
const uint32_t *src;
uint32_t *dest;
#ifdef CONFIG_ARMV7M_STACKCHECK
/* Set the stack limit before we attempt to call any functions */
__asm__ volatile ("sub r10, sp, %0" : : "r" (CONFIG_IDLETHREAD_STACKSIZE - 64) : );
#endif
/* Configure the uart so that we can get debug output as soon as possible */
stm32_clockconfig();//初始化时钟
stm32_fpuconfig(); //配置FMU
stm32_lowsetup(); //初始化基本串口
stm32_gpioinit(); //配置IO
showprogress('A');
/* Clear .bss. We'll do this inline (vs. calling memset) just to be
* certain that there are no issues with the state of global variables.
*/
for (dest = &_sbss; dest < &_ebss; )
{
*dest++ = 0;
}
showprogress('B');
/* Move the intialized data section from his temporary holding spot in
* FLASH into the correct place in SRAM. The correct place in SRAM is
* give by _sdata and _edata. The temporary location is in FLASH at the
* end of all of the other read-only data (.text, .rodata) at _eronly.
*/
for (src = &_eronly, dest = &_sdata; dest < &_edata; )
{
*dest++ = *src++;
}
showprogress('C');
/* Perform early serial initialization */
#ifdef USE_EARLYSERIALINIT
up_earlyserialinit();
#endif
showprogress('D');
/* For the case of the separate user-/kernel-space build, perform whatever
* platform specific initialization of the user memory is required.
* Normally this just means initializing the user space .data and .bss
* segments.
*/
#ifdef CONFIG_NUTTX_KERNEL
stm32_userspace();
showprogress('E');
#endif
/* Initialize onboard resources */
stm32_boardinitialize(); //板层初始化
showprogress('F');
/* Then start NuttX */
showprogress('\r');
showprogress('\n');
os_start(); //启动Nuttx
/* Shoulnd't get here */
for(;;);
}
(2)os_start(); //启动Nuttx
****************************************************************************/
void os_start(void)
{
int i;
slldbg("Entry\n");
/* Initialize RTOS Data ***************************************************/
/* Initialize all task lists */
dq_init(&g_readytorun); /
dq_init(&g_pendingtasks);
dq_init(&g_waitingforsemaphore);
#ifndef CONFIG_DISABLE_SIGNALS
dq_init(&g_waitingforsignal);
#endif
#ifndef CONFIG_DISABLE_MQUEUE
dq_init(&g_waitingformqnotfull);
dq_init(&g_waitingformqnotempty);
#endif
#ifdef CONFIG_PAGING
dq_init(&g_waitingforfill);
#endif
dq_init(&g_inactivetasks);
sq_init(&g_delayed_kufree);
#if defined(CONFIG_NUTTX_KERNEL) && defined(CONFIG_MM_KERNEL_HEAP)
sq_init(&g_delayed_kfree);
#endif
/* Initialize the logic that determine unique process IDs. */
g_lastpid = 0;
for (i = 0; i < CONFIG_MAX_TASKS; i++)
{
g_pidhash[i].tcb = NULL;
g_pidhash[i].pid = INVALID_PROCESS_ID;
}
/* Assign the process ID of ZERO to the idle task */
g_pidhash[ PIDHASH(0)].tcb = &g_idletcb.cmn;
g_pidhash[ PIDHASH(0)].pid = 0;
/* Initialize the IDLE task TCB *******************************************/
/* Initialize a TCB for this thread of execution. NOTE: The default
* value for most components of the g_idletcb are zero. The entire
* structure is set to zero. Then only the (potentially) non-zero
* elements are initialized. NOTE: The idle task is the only task in
* that has pid == 0 and sched_priority == 0.
*/
bzero((void*)&g_idletcb, sizeof(struct task_tcb_s));
g_idletcb.cmn.task_state = TSTATE_TASK_RUNNING;
g_idletcb.cmn.entry.main = (main_t)os_start;
/* Set the IDLE task name */
#if CONFIG_TASK_NAME_SIZE > 0
strncpy(g_idletcb.cmn.name, g_idlename, CONFIG_TASK_NAME_SIZE-1);
#endif /* CONFIG_TASK_NAME_SIZE */
/* Configure the task name in the argument list. The IDLE task does
* not really have an argument list, but this name is still useful
* for things like the NSH PS command.
*
* In the kernel mode build, the arguments are saved on the task's stack
* and there is no support that yet.
*/
#if defined(CONFIG_CUSTOM_STACK) || !defined(CONFIG_NUTTX_KERNEL)
#if CONFIG_TASK_NAME_SIZE > 0
g_idletcb.argv[0] = g_idletcb.cmn.name;
#else
g_idletcb.argv[0] = (char*)g_idlename;
#endif /* CONFIG_TASK_NAME_SIZE */
#endif /* CONFIG_CUSTOM_STACK || !CONFIG_NUTTX_KERNEL */
/* Then add the idle task's TCB to the head of the ready to run list */
dq_addfirst((FAR dq_entry_t*)&g_idletcb, (FAR dq_queue_t*)&g_readytorun);
/* Initialize the processor-specific portion of the TCB */
up_initial_state(&g_idletcb.cmn);
/* Initialize RTOS facilities *********************************************/
/* Initialize the semaphore facility(if in link). This has to be done
* very early because many subsystems depend upon fully functional
* semaphores.
*/
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (sem_initialize != NULL)
#endif
{
sem_initialize();
}
/* Initialize the memory manager */
{
FAR void *heap_start;
size_t heap_size;
/* Get the user-mode heap from the platform specific code and configure
* the user-mode memory allocator.
*/
up_allocate_heap(&heap_start, &heap_size);
kumm_initialize(heap_start, heap_size);
#if defined(CONFIG_NUTTX_KERNEL) && defined(CONFIG_MM_KERNEL_HEAP)
/* Get the kernel-mode heap from the platform specific code and configure
* the kernel-mode memory allocator.
*/
up_allocate_kheap(&heap_start, &heap_size);
kmm_initialize(heap_start, heap_size);
#endif
}
/* Initialize tasking data structures */
#if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS)
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (task_initialize != NULL)
#endif
{
task_initialize();
}
#endif
/* Initialize the interrupt handling subsystem (if included) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (irq_initialize != NULL)
#endif
{
irq_initialize();
}
/* Initialize the watchdog facility (if included in the link) */
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (wd_initialize != NULL)
#endif
{
wd_initialize();
}
/* Initialize the POSIX timer facility (if included in the link) */
#ifndef CONFIG_DISABLE_CLOCK
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (clock_initialize != NULL)
#endif
{
clock_initialize();
}
#endif
#ifndef CONFIG_DISABLE_POSIX_TIMERS
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (timer_initialize != NULL)
#endif
{
timer_initialize();
}
#endif
/* Initialize the signal facility (if in link) */
#ifndef CONFIG_DISABLE_SIGNALS
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (sig_initialize != NULL)
#endif
{
sig_initialize();
}
#endif
/* Initialize the named message queue facility (if in link) */
#ifndef CONFIG_DISABLE_MQUEUE
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (mq_initialize != NULL)
#endif
{
mq_initialize();
}
#endif
/* Initialize the thread-specific data facility (if in link) */
#ifndef CONFIG_DISABLE_PTHREAD
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (pthread_initialize != NULL)
#endif
{
pthread_initialize();
}
#endif
/* Initialize the file system (needed to support device drivers) */
#if CONFIG_NFILE_DESCRIPTORS > 0
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (fs_initialize != NULL)
#endif
{
fs_initialize();
}
#endif
/* Initialize the network system */
#ifdef CONFIG_NET
#if 0
if (net_initialize != NULL)
#endif
{
net_initialize();
}
#endif
/* The processor specific details of running the operating system
* will be handled here. Such things as setting up interrupt
* service routines and starting the clock are some of the things
* that are different for each processor and hardware platform.
*/
up_initialize();
/* Initialize the C libraries (if included in the link). This
* is done last because the libraries may depend on the above.
*/
#ifdef CONFIG_HAVE_WEAKFUNCTIONS
if (lib_initialize != NULL)
#endif
{
lib_initialize();
}
/* IDLE Group Initialization **********************************************/
/* Allocate the IDLE group and suppress child status. */
#ifdef HAVE_TASK_GROUP
DEBUGVERIFY(group_allocate(&g_idletcb));
#endif
/* Create stdout, stderr, stdin on the IDLE task. These will be
* inherited by all of the threads created by the IDLE task.
*/
DEBUGVERIFY(group_setupidlefiles(&g_idletcb));
/* Complete initialization of the IDLE group. Suppress retention
* of child status in the IDLE group.
*/
#ifdef HAVE_TASK_GROUP
DEBUGVERIFY(group_initialize(&g_idletcb));
g_idletcb.cmn.group->tg_flags = GROUP_FLAG_NOCLDWAIT;
#endif
/* Bring Up the System ****************************************************/
/* Create initial tasks and bring-up the system */
DEBUGVERIFY(os_bringup());
/* The IDLE Loop **********************************************************/
/* When control is return to this point, the system is idle. */
sdbg("Beginning Idle Loop\n");
for (;;)
{
/* Perform garbage collection (if it is not being done by the worker
* thread). This cleans-up memory de-allocations that were queued
* because they could not be freed in that execution context (for
* example, if the memory was freed from an interrupt handler).
*/
#ifndef CONFIG_SCHED_WORKQUEUE
/* We must have exclusive access to the memory manager to do this
* BUT the idle task cannot wait on a semaphore. So we only do
* the cleanup now if we can get the semaphore -- this should be
* possible because if the IDLE thread is running, no other task is!
*/
if (kmm_trysemaphore() == 0)
{
sched_garbagecollection();
kmm_givesemaphore();
}
#endif
/* Perform any processor-specific idle state operations */
up_idle();
}
}
（3）os_bringup（）函数
int os_bringup(void)
{
int taskid;
/* Setup up the initial environment for the idle task. At present, this
* may consist of only the initial PATH variable. The PATH variable is
* (probably) not used by the IDLE task. However, the environment
* containing the PATH variable will be inherited by all of the threads
* created by the IDLE task.
*/
#if !defined(CONFIG_DISABLE_ENVIRON) && defined(CONFIG_PATH_INITIAL)
(void)setenv("PATH", CONFIG_PATH_INITIAL, 1);
#endif
/* Start the page fill worker kernel thread that will resolve page faults.
* This should always be the first thread started because it may have to
* resolve page faults in other threads
*/
#ifdef CONFIG_PAGING
svdbg("Starting paging thread\n");
g_pgworker = KERNEL_THREAD("pgfill", CONFIG_PAGING_DEFPRIO,
CONFIG_PAGING_STACKSIZE,
(main_t)pg_worker, (FAR char * const *)NULL);
DEBUGASSERT(g_pgworker > 0);
#endif
/* Start the worker thread that will serve as the device driver "bottom-
* half" and will perform misc garbage clean-up.
*/
#ifdef CONFIG_SCHED_WORKQUEUE
#ifdef CONFIG_SCHED_HPWORK
#ifdef CONFIG_SCHED_LPWORK
svdbg("Starting high-priority kernel worker thread\n");
#else
svdbg("Starting kernel worker thread\n");
#endif
g_work[HPWORK].pid = KERNEL_THREAD(HPWORKNAME, CONFIG_SCHED_WORKPRIORITY,
CONFIG_SCHED_WORKSTACKSIZE,
(main_t)work_hpthread, (FAR char * const *)NULL);
DEBUGASSERT(g_work[HPWORK].pid > 0);
/* Start a lower priority worker thread for other, non-critical continuation
* tasks
*/
#ifdef CONFIG_SCHED_LPWORK
svdbg("Starting low-priority kernel worker thread\n");
g_work[LPWORK].pid = KERNEL_THREAD(LPWORKNAME, CONFIG_SCHED_LPWORKPRIORITY,
CONFIG_SCHED_LPWORKSTACKSIZE,
(main_t)work_lpthread, (FAR char * const *)NULL);
DEBUGASSERT(g_work[LPWORK].pid > 0);
#endif /* CONFIG_SCHED_LPWORK */
#endif /* CONFIG_SCHED_HPWORK */
#if defined(CONFIG_NUTTX_KERNEL) && defined(CONFIG_SCHED_USRWORK)
/* Start the user-space work queue */
DEBUGASSERT(USERSPACE->work_usrstart != NULL);
taskid = USERSPACE->work_usrstart();
DEBUGASSERT(taskid > 0);
#endif
#endif /* CONFIG_SCHED_WORKQUEUE */
/* Once the operating system has been initialized, the system must be
* started by spawning the user init thread of execution. This is the
* first user-mode thead.
*/
svdbg("Starting init thread\n");
/* Perform any last-minute, board-specific initialization, if so
* configured.
*/
#ifdef CONFIG_BOARD_INITIALIZE
board_initialize();
#endif
/* Start the default application. In a flat build, this is entrypoint
* is given by the definitions, CONFIG_USER_ENTRYPOINT. In the kernel
* build, however, we must get the address of the entrypoint from the
* header at the beginning of the user-space blob.
*/
#ifdef CONFIG_NUTTX_KERNEL
DEBUGASSERT(USERSPACE->us_entrypoint != NULL);
taskid = TASK_CREATE("init", SCHED_PRIORITY_DEFAULT,
CONFIG_USERMAIN_STACKSIZE, USERSPACE->us_entrypoint, //启动入口us_entrypoint = (main_t)CONFIG_USER_ENTRYPOINT,
(FAR char * const *)NULL);
#else
taskid = TASK_CREATE("init", SCHED_PRIORITY_DEFAULT,
CONFIG_USERMAIN_STACKSIZE,
(main_t)CONFIG_USER_ENTRYPOINT, //启动入口
(FAR char * const *)NULL);
#endif
ASSERT(taskid > 0);
/* We an save a few bytes by discarding the IDLE thread's environment. */
#if !defined(CONFIG_DISABLE_ENVIRON) && defined(CONFIG_PATH_INITIAL)
(void)clearenv();
#endif
return OK;
}
CONFIG_USER_ENTRYPOINT=”nsh_main”
CONFIG_USER_ENTRYPOINT=”user_start”
（4）nsh_mian（）函数
int nsh_main(int argc, char *argv[])
{
int exitval = 0;
int ret;
/* Call all C++ static constructors */
#if defined(CONFIG_HAVE_CXX) && defined(CONFIG_HAVE_CXXINITIALIZE)
up_cxxinitialize();
#endif
/* Make sure that we are using our symbol take */
#if defined(CONFIG_LIBC_EXECFUNCS) && defined(CONFIG_EXECFUNCS_SYMTAB)
exec_setsymtab(CONFIG_EXECFUNCS_SYMTAB, 0);
#endif
/* Register the BINFS file system */
#if defined(CONFIG_FS_BINFS) && (CONFIG_BUILTIN)
ret = builtin_initialize();
if (ret < 0)
{
fprintf(stderr, "ERROR: builtin_initialize failed: %d\n", ret);
exitval = 1;
}
#endif
/* Initialize the NSH library */
nsh_initialize();
/* If the Telnet console is selected as a front-end, then start the
* Telnet daemon.
*/
#ifdef CONFIG_NSH_TELNET
ret = nsh_telnetstart();
if (ret < 0)
{
/* The daemon is NOT running. Report the the error then fail...
* either with the serial console up or just exiting.
*/
fprintf(stderr, "ERROR: Failed to start TELNET daemon: %d\n", ret);
exitval = 1;
}
#endif
/* If the serial console front end is selected, then run it on this thread */
#ifdef CONFIG_NSH_CONSOLE
ret = nsh_consolemain(0, NULL); //核心文件
/* nsh_consolemain() should not return. So if we get here, something
* is wrong.
*/
fprintf(stderr, "ERROR: nsh_consolemain() returned: %d\n", ret);
exitval = 1;
#endif
return exitval;
}
int nsh_consolemain(int argc, char *argv[])
{
FAR struct console_stdio_s *pstate = nsh_newconsole();
int ret;
DEBUGASSERT(pstate);
/* Execute the start-up script */
#ifdef CONFIG_NSH_ROMFSETC
(void)nsh_initscript(&pstate->cn_vtbl);
#endif
/* Initialize any USB tracing options that were requested */
#ifdef CONFIG_NSH_USBDEV_TRACE
usbtrace_enable(TRACE_BITSET);
#endif
/* Execute the session */
ret = nsh_session(pstate);
/* Exit upon return */
nsh_exit(&pstate->cn_vtbl, ret);
return ret;
}到这里我们只关心这个函数nsh_consolemain（）-——》nsh_initscript()——》nsh_script()
int nsh_initscript(FAR struct nsh_vtbl_s *vtbl)
{
static bool initialized;
bool already;
int ret = OK;
/* Atomic test and set of the initialized flag */
sched_lock();
already = initialized;
initialized = true;
sched_unlock();
/* If we have not already executed the init script, then do so now */
if (!already)
{
ret = nsh_script(vtbl, "init", NSH_INITPATH);//解析脚本函数
}
return ret;
}
到这里我们就要看rcS文件
#!nsh
#
# PX4FMU startup script.
#
# This script is responsible for:
#
# - mounting the microSD card (if present)
# - running the user startup script from the microSD card (if present)
# - detecting the configuration of the system and picking a suitable
# startup script to continue with
#
# Note: DO NOT add configuration-specific commands to this script;
# add them to the per-configuration scripts instead.
#
set USB autoconnect
set NSH_ERROR_UART1 /dev/ttyACM0
set NSH_ERROR_UART2 /dev/ttyS0
#
# Try to mount the microSD card.
#
echo "[init] looking for microSD..."
if mount -t vfat /dev/mmcsd0 /fs/microsd
then
echo "[init] card mounted at /fs/microsd"
set HAVE_MICROSD 1
# Start playing the startup tune
if [ -f /etc/tones/startup ]
then
tone_alarm /etc/tones/startup
else
tone_alarm 1
fi
else
set HAVE_MICROSD 0
tone_alarm MNBGG
fi
# Look for an additional init script that allows changing the default
# behavior. Settings may be overriden in the following order:
#
# board-specific file
# etc/rc on microSD card
# etc/rc.txt on microSD card
if [ -f /etc/init.d/rc.board ]
then
echo "[init] reading /etc/init.d/rc.board"
sh /etc/init.d/rc.board
fi
if [ -f /fs/microsd/etc/rc ]
then
echo "[init] reading /fs/microsd/etc/rc"
sh /fs/microsd/etc/rc
fi
# Also consider rc.txt files
if [ -f /fs/microsd/etc/rc.txt ]
then
echo "[init] reading /fs/microsd/etc/rc.txt"
sh /fs/microsd/etc/rc.txt
fi
#
# Check for USB host
#
if [ $USB != autoconnect ]
then
echo "[init] not connecting USB"
else
if sercon
then
echo "[init] USB interface connected"
else
echo "[init] No USB connected"
fi
fi
if [ $HAVE_MICROSD == 0 ]
then
if usb_connected
then
echo "Opening USB nsh"
else
echo "booting with no microSD"
set HAVE_MICROSD 1
fi
fi
# if this is an APM build then there will be a rc.APM script
# from an EXTERNAL_SCRIPTS build option
if [ -f /etc/init.d/rc.APM -a $HAVE_MICROSD == 1 -a ! -f /fs/microsd/APM/nostart ]
then
echo Running rc.APM
# if APM startup is successful then nsh will exit
sh /etc/init.d/rc.APM
else
nshterm /dev/ttyACM0 &
fi
继续执行rc.APM
#!nsh
# APM startup script for NuttX on PX4
# To disable APM startup add a /fs/microsd/APM/nostart file
# check for an old file called APM, caused by
# a bug in an earlier firmware release
if [ -f /fs/microsd/APM ]
then
echo "APM file found - renaming"
mv /fs/microsd/APM /fs/microsd/APM.old
fi
if [ -f /fs/microsd/APM/nostart ]
then
echo "APM/nostart found - skipping APM startup"
sh /etc/init.d/rc.error
fi
# mount binfs so we can find the built-in apps
if [ -f /bin/reboot ]
then
echo "binfs already mounted"
else
echo "Mounting binfs"
if mount -t binfs /dev/null /bin
then
echo "binfs mounted OK"
else
sh /etc/init.d/rc.error
fi
fi
set sketch NONE
if rm /fs/microsd/APM/boot.log
then
echo "removed old boot.log"
fi
set logfile /fs/microsd/APM/BOOT.LOG
if [ ! -f /bin/ArduPilot ]
then
echo "/bin/ardupilot not found"
sh /etc/init.d/rc.error
fi
if mkdir /fs/microsd/APM > /dev/null
then
echo "Created APM directory"
fi
if uorb start
then
echo "uorb started OK"
else
sh /etc/init.d/rc.error
fi
echo Starting ArduPilot
if ArduPilot start
then
echo ArduPilot started OK
else
sh /etc/init.d/rc.error
fi
echo "rc.APM finished"
到这里我们会调用：
if ArduPilot start
then
echo ArduPilot started OK
到这里可以看出apm和px4的启动还是有很大的差别
（5）user_start（）函数
int user_start(int argc, char *argv[])
{
// detect hw version
hw_detect();
/* configure the first 8 PWM outputs (i.e. all of them) */
up_pwm_servo_init(0xff);
/* run C++ ctors before we go any further */
up_cxxinitialize();
/* reset all to zero */
memset(&system_state, 0, sizeof(system_state));
/* configure the high-resolution time/callout interface */
hrt_init();
/* calculate our fw CRC so FMU can decide if we need to update */
calculate_fw_crc();
/*
* Poll at 1ms intervals for received bytes that have not triggered
* a DMA event.
*/
#ifdef CONFIG_ARCH_DMA
hrt_call_every(&serial_dma_call, 1000, 1000, (hrt_callout)stm32_serial_dma_poll, NULL);
#endif
/* print some startup info */
lowsyslog("\nPX4IO: starting\n");
/* default all the LEDs to off while we start */
LED_AMBER(false);
LED_BLUE(false);
LED_SAFETY(false);
#ifdef GPIO_LED4
LED_RING(false);
#endif
/* turn on servo power (if supported) */
#ifdef POWER_SERVO
POWER_SERVO(true);
#endif
/* turn off S.Bus out (if supported) */
#ifdef ENABLE_SBUS_OUT
ENABLE_SBUS_OUT(false);
#endif
/* start the safety switch handler */
safety_init();
/* initialise the control inputs */
controls_init();
/* set up the ADC */
adc_init();
/* start the FMU interface */
interface_init();
/* add a performance counter for mixing */
perf_counter_t mixer_perf = perf_alloc(PC_ELAPSED, "mix");
/* add a performance counter for controls */
perf_counter_t controls_perf = perf_alloc(PC_ELAPSED, "controls");
/* and one for measuring the loop rate */
perf_counter_t loop_perf = perf_alloc(PC_INTERVAL, "loop");
struct mallinfo minfo = mallinfo();
lowsyslog("MEM: free %u, largest %u\n", minfo.mxordblk, minfo.fordblks);
/* initialize PWM limit lib */
pwm_limit_init(&pwm_limit);
/*
* P O L I C E L I G H T S
*
* Not enough memory, lock down.
*
* We might need to allocate mixers later, and this will
* ensure that a developer doing a change will notice
* that he just burned the remaining RAM with static
* allocations. We don't want him to be able to
* get past that point. This needs to be clearly
* documented in the dev guide.
*
*/
if (minfo.mxordblk < 600) {
lowsyslog("ERR: not enough MEM");
bool phase = false;
while (true) {
if (phase) {
LED_AMBER(true);
LED_BLUE(false);
} else {
LED_AMBER(false);
if (r_page_config[PX4IO_P_CONFIG_HARDWARE_VERSION] != 3) {
LED_BLUE(true);
}
}
up_udelay(250000);
phase = !phase;
}
}
/* Start the failsafe led init */
failsafe_led_init();
/*
* Run everything in a tight loop.
*/
uint64_t last_debug_time = 0;
for (;;) {
/* track the rate at which the loop is running */
perf_count(loop_perf);
/* kick the mixer */
perf_begin(mixer_perf);
if (!(r_setup_features & PX4IO_P_SETUP_FEATURES_ONESHOT)) {
/*
when in oneshot we don't trigger output
until we get new data from the FMU
*/
mixer_tick();
}
perf_end(mixer_perf);
/* kick the control inputs */
perf_begin(controls_perf);
controls_tick();
perf_end(controls_perf);
check_reboot();
/* check for debug activity (default: none) */
show_debug_messages();
/* post debug state at ~1Hz - this is via an auxiliary serial port
* DEFAULTS TO OFF!
*/
if (hrt_absolute_time() - last_debug_time > (1000 * 1000)) {
isr_debug(1, "d:%u s=0x%x a=0x%x f=0x%x m=%u",
(unsigned)r_page_setup[PX4IO_P_SETUP_SET_DEBUG],
(unsigned)r_status_flags,
(unsigned)r_setup_arming,
(unsigned)r_setup_features,
(unsigned)mallinfo().mxordblk);
last_debug_time = hrt_absolute_time();
}
if (r_page_setup[PX4IO_P_SETUP_HEATER_DUTY_CYCLE] <= PX4IO_HEATER_MAX) {
control_IMU_heater(r_page_setup[PX4IO_P_SETUP_HEATER_DUTY_CYCLE]);
} else if (r_page_config[PX4IO_P_CONFIG_HARDWARE_VERSION] == 3) {
// pixhawk2 with no target temperature
control_IMU_heater(0);
} else {
control_heartbeat_LED();
}
}
}
