/*
 * File      : idle.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rt-thread.org/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 * 2006-03-23     Bernard      the first version
 * 2010-11-10     Bernard      add cleanup callback function in thread exit.
 */

#include <rthw.h>
#include <rtthread.h>

#ifndef IDLE_THREAD_STACK_SIZE
#if defined (RT_USING_HOOK) || defined(RT_USING_HEAP)
#define IDLE_THREAD_STACK_SIZE  256
#else
#define IDLE_THREAD_STACK_SIZE  128
#endif
#endif

static struct rt_thread idle;
ALIGN(RT_ALIGN_SIZE)
static rt_uint8_t rt_thread_stack[IDLE_THREAD_STACK_SIZE];

extern rt_list_t rt_thread_defunct;

#ifdef RT_USING_HOOK
/**
 * @addtogroup Hook
 */

/*@{*/

static void (*rt_thread_idle_hook)();

/**
 * This function will set a hook function to idle thread loop.
 *
 * @param hook the specified hook function
 *
 * @note the hook function must be simple and never be blocked or suspend.
 */
void rt_thread_idle_sethook(void (*hook)())
{
    rt_thread_idle_hook = hook;
}

/*@}*/
#endif

/**
 * @ingroup Thread
 *
 * This function will perform system background job when system idle.
 */
void rt_thread_idle_excute(void)
{
    /* check the defunct thread list */
    if (!rt_list_isempty(&rt_thread_defunct))
    {
        rt_base_t lock;
        rt_thread_t thread;
#ifdef RT_USING_MODULE
        rt_module_t module = RT_NULL;
#endif
        RT_DEBUG_NOT_IN_INTERRUPT;

        /* disable interrupt */
        lock = rt_hw_interrupt_disable();

        /* re-check whether list is empty */
        if (!rt_list_isempty(&rt_thread_defunct))
        {
            /* get defunct thread */
            thread = rt_list_entry(rt_thread_defunct.next,
                                   struct rt_thread,
                                   tlist);
#ifdef RT_USING_MODULE
            /* get thread's parent module */
            module = (rt_module_t)thread->module_id;

            /* if the thread is module's main thread */
            if (module != RT_NULL && module->module_thread == thread)
            {
                /* detach module's main thread */
                module->module_thread = RT_NULL;
            }
#endif
            /* remove defunct thread */
            rt_list_remove(&(thread->tlist));
            /* invoke thread cleanup */
            if (thread->cleanup != RT_NULL)
                thread->cleanup(thread);

            /* if it's a system object, not delete it */
            if (rt_object_is_systemobject((rt_object_t)thread) == RT_TRUE)
            {
                /* enable interrupt */
                rt_hw_interrupt_enable(lock);

                return;
            }
        }
        else
        {
            /* enable interrupt */
            rt_hw_interrupt_enable(lock);

            /* may the defunct thread list is removed by others, just return */
            return;
        }

        /* enable interrupt */
        rt_hw_interrupt_enable(lock);

#ifdef RT_USING_HEAP
#if defined(RT_USING_MODULE) && defined(RT_USING_SLAB)
        /* the thread belongs to an application module */
        if (thread->flags & RT_OBJECT_FLAG_MODULE)
            rt_module_free((rt_module_t)thread->module_id, thread->stack_addr);
        else
#endif
        /* release thread's stack */
        rt_free(thread->stack_addr);
        /* delete thread object */
        rt_object_delete((rt_object_t)thread);
#endif

#ifdef RT_USING_MODULE
        if (module != RT_NULL)
        {
            extern rt_err_t rt_module_destroy(rt_module_t module);

            /* if sub thread list and main thread are all empty */
            if ((module->module_thread == RT_NULL) &&
                rt_list_isempty(&module->module_object[RT_Object_Class_Thread].object_list))
            {
                module->nref --;
            }

            /* destroy module */
            if (module->nref == 0)
                rt_module_destroy(module);
        }
#endif
    }
}

static void rt_thread_idle_entry(void *parameter)
{
    while (1)
    {
        #ifdef RT_USING_HOOK
        if (rt_thread_idle_hook != RT_NULL)
            rt_thread_idle_hook();
        #endif

        rt_thread_idle_excute();
    }
}

/**
 * @ingroup SymstemInit
 *
 * This function will initialize idle thread, then start it.
 *
 * @note this function must be invoked when system init.
 */
void rt_thread_idle_init(void)
{
    /* initialize thread */
    rt_thread_init(&idle,
                   "tidle",
                   rt_thread_idle_entry,
                   RT_NULL,
                   &rt_thread_stack[0],
                   sizeof(rt_thread_stack),
                   RT_THREAD_PRIORITY_MAX - 1,
                   32);

    /* startup */
    rt_thread_startup(&idle);
}