MQX学习笔记（二）

/*MQX通过下面的代码（任务模板），向系统注册多个用户进程：--- 当然，我们也可以通过MQX的接口函数来创建任务。*/

const TASK_TEMPLATE_STRUCT  MQX_template_list[] = 
{
　　/* Task Index， Function， Stack， Priority， Name， Attributes， Param， Time Slice */
　　{SDCARD_TASK，sdcard_task，2000，11，"SDcard"，MQX_AUTO_START_TASK，0， 0 }， 
　　{ 0 }
}；

int main( void )
{ /* Body */
    extern const MQX_INITIALIZATION_STRUCT MQX_init_struct;
    /* Start MQX */
    _mqx( (MQX_INITIALIZATION_STRUCT_PTR) &MQX_init_struct );

    return 0;
} /* Endbody */

extern TASK_TEMPLATE_STRUCT MQX_template_list[];

const MQX_INITIALIZATION_STRUCT  MQX_init_struct =
{
    /* PROCESSOR_NUMBER                */  BSP_DEFAULT_PROCESSOR_NUMBER,
    /* START_OF_KERNEL_MEMORY          */  BSP_DEFAULT_START_OF_KERNEL_MEMORY,
    /* END_OF_KERNEL_MEMORY            */  BSP_DEFAULT_END_OF_KERNEL_MEMORY,
    /* INTERRUPT_STACK_SIZE            */  BSP_DEFAULT_INTERRUPT_STACK_SIZE,
    /* TASK_TEMPLATE_LIST              */  MQX_template_list,
    /* MQX_HARDWARE_INTERRUPT_LEVEL_MAX*/  BSP_DEFAULT_MQX_HARDWARE_INTERRUPT_LEVEL_MAX,
    /* MAX_MSGPOOLS                    */  BSP_DEFAULT_MAX_MSGPOOLS,
    /* MAX_MSGQS                       */  BSP_DEFAULT_MAX_MSGQS,
    /* IO_CHANNEL                      */  BSP_DEFAULT_IO_CHANNEL,
    /* IO_OPEN_MODE                    */  BSP_DEFAULT_IO_OPEN_MODE,
    0,
    0,
#if MQX_ENABLE_USER_MODE   
    BSP_DEFAULT_START_OF_KERNEL_AREA,
    BSP_DEFAULT_END_OF_KERNEL_AREA,

    BSP_DEFAULT_START_OF_USER_DEFAULT_MEMORY,
    BSP_DEFAULT_END_OF_USER_DEFAULT_MEMORY,

    BSP_DEFAULT_START_OF_USER_HEAP,
    BSP_DEFAULT_END_OF_USER_HEAP,

    BSP_DEFAULT_START_OF_USER_RW_MEMORY,
    BSP_DEFAULT_END_OF_USER_RW_MEMORY,

    BSP_DEFAULT_START_OF_USER_RO_MEMORY,
    BSP_DEFAULT_END_OF_USER_RO_MEMORY,

    BSP_DEFAULT_START_OF_USER_NO_MEMORY,
    BSP_DEFAULT_END_OF_USER_NO_MEMORY,

    BSP_DEFAULT_MAX_USER_TASK_PRIORITY,
    BSP_DEFAULT_MAX_USER_TASK_COUNT,
#endif
};

/*!
 * \brief Initializes and starts MQX on the processor.
 * 
 * The function does the following:
 * \li Initializes the default memory pool and memory components.
 * \li Initializes kernel data.
 * \li Performs BSP-specific initialization, which includes installing the 
 * periodic timer.
 * \li Performs PSP-specific initialization.
 * \li Creates the interrupt stack.
 * \li Creates the ready queues.
 * \li Starts MQX tasks.
 * \li Starts autostart application tasks.
 * 
 * \param[in] mqx_init Pointer to the MQX initialization structure for the 
 * processor.
 * 
 * \return Does not return (Success.)
 * \return If application called _mqx_exit(), error code that it passed to 
 * _mqx_exit() (Success.)
 * \return Errors from _int_install_isr() (MQX cannot install the interrupt 
 *  subsystem.)
 * \return Errors from _io_init() (MQX cannot install the I/O subsystem.)
 * \return Errors from _mem_alloc_system() (There is not enough memory to 
 * allocate either the interrupt stack or the interrupt table.)
 * \return Errors from _mem_alloc_zero() (There is not enough memory to allocate 
 * the ready queues.)
 * \return MQX_KERNEL_MEMORY_TOO_SMALL (Init_struct_ptr does not specify enough 
 * kernel memory.)
 * \return MQX_OUT_OF_MEMORY (There is not enough memory to allocate either the 
 * ready queues, the interrupt stack, or the interrupt table.)
 * \return MQX_TIMER_ISR_INSTALL_FAIL (MQX cannot install the periodic timer ISR.)
 * 
 * \warning Must be called exactly once per processor.
 * 
 * \see _mqx_exit
 * \see _int_install_isr
 * \see _mem_alloc() 
 * \see _mem_alloc_from()
 * \see _mem_alloc_system()
 * \see _mem_alloc_system_from()
 * \see _mem_alloc_system_zero()
 * \see _mem_alloc_system_zero_from()
 * \see _mem_alloc_zero()
 * \see _mem_alloc_zero_from()
 * \see _mem_alloc_align()
 * \see _mem_alloc_align_from()
 * \see _mem_alloc_at()
 * \see MQX_INITIALIZATION_STRUCT
 * \see TASK_TEMPLATE_STRUCT        
 */ 
_mqx_uint _mqx( register MQX_INITIALIZATION_STRUCT_PTR mqx_init )
{ /* Body */
    KERNEL_DATA_STRUCT_PTR  kernel_data;
    TASK_TEMPLATE_STRUCT_PTR  template_ptr; /*任务模板指针*/
    TD_STRUCT_PTR  td_ptr;
    _mqx_uint  result;
    pointer  stack_ptr;
    pointer  sys_td_stack_ptr;
    uchar_ptr  sys_stack_base_ptr;
    /*
     * The kernel data structure starts at the start of kernel memory,
     * as specified in the initialization structure. Make sure address
     * specified is aligned
     */
    kernel_data = (KERNEL_DATA_STRUCT_PTR) _ALIGN_ADDR_TO_HIGHER_MEM(mqx_init->START_OF_KERNEL_MEMORY);

    /* Set the global pointer to the kernel data structure */
    _SET_KERNEL_DATA(kernel_data);

    /* The following assignments are done to force the linker to include
     * the symbols, which are required by TAD.
     * Note that we should use address of the variable so it is not optimized
     * as direct constant assignment when optimization level is high.
     * Note that counter will be immediately reset to zero on the subsequent
     * _mem_zero call. */
    *(volatile pointer*) kernel_data = (pointer) & _mqx_version_number;
    *(volatile pointer*) kernel_data = (pointer) & _mqx_vendor;

    /* Initialize the kernel data to zero. */
    _mem_zero((pointer) kernel_data, (_mem_size) sizeof(KERNEL_DATA_STRUCT));

    /* Copy the MQX initialization structure into kernel data. */
    kernel_data->INIT = *mqx_init;
    kernel_data->INIT.START_OF_KERNEL_MEMORY = (pointer) kernel_data;
    kernel_data->INIT.END_OF_KERNEL_MEMORY = (pointer) _ALIGN_ADDR_TO_LOWER_MEM(kernel_data->INIT.END_OF_KERNEL_MEMORY);

    /* init kernel data structures */
    _mqx_init_kernel_data_internal();

    /* Initialize the memory resource manager for the kernel */
    result = _mem_init_internal();

    /*
     * Set the stack for the system TD, in case the idle task gets blocked
     * by an exception or if idle task is not used.
     */
    result = PSP_MINSTACKSIZE;
    sys_td_stack_ptr = _mem_alloc_system((_mem_size) result);

    _mem_set_type(sys_td_stack_ptr, MEM_TYPE_SYSTEM_STACK);

    sys_stack_base_ptr = (uchar_ptr) _GET_STACK_BASE(sys_td_stack_ptr, result);
    td_ptr = SYSTEM_TD_PTR(kernel_data);
    td_ptr->STACK_PTR = (pointer)(sys_stack_base_ptr - sizeof(PSP_STACK_START_STRUCT));
    td_ptr->STACK_BASE = sys_stack_base_ptr;

    _mqx_system_stack = td_ptr->STACK_PTR;

    /* Build the MQX ready to run queues */
    result = _psp_init_readyqs();

    /* Create a light wait semaphore for task creation/destruction creation */
    _lwsem_create((LWSEM_STRUCT_PTR) & kernel_data->TASK_CREATE_LWSEM, 1);

    /* Call bsp to enable timers and other devices */
    result = _bsp_enable_card();

    /* Check here for auto-create tasks, and create them here */   /*加载用户任务列表*/
    template_ptr = kernel_data->INIT.TASK_TEMPLATE_LIST;
    while (template_ptr->TASK_TEMPLATE_INDEX) {
        if (template_ptr->TASK_ATTRIBUTES & MQX_AUTO_START_TASK) {   /*检测任务属性*/
            td_ptr = _task_init_internal(     /*创建任务，返回任务描述符*/
                    template_ptr,  /*任务列表指针*/
                    kernel_data->ACTIVE_PTR->TASK_ID,
                    template_ptr->CREATION_PARAMETER, 
                    FALSE, 
                    NULL, 
                    0
                );
        
#if MQX_CHECK_MEMORY_ALLOCATION_ERRORS
            if (td_ptr == NULL) {
                _mqx_exit(MQX_OUT_OF_MEMORY);
            } /* Endif */
#endif
            _task_ready_internal(td_ptr); /*把任务加入运行队列*/
        } /* Endif */
        ++template_ptr;  /*指针加1  */
    } /* Endwhile */

    _sched_start_internal(); /* WILL NEVER RETURN FROM HERE */

    return MQX_OK; /* To satisfy lint */

} /* Endbody */