【IoT迷你赛】TencentOS学习源码分析（1）——task

#define K_TASK_PRIO_IDLE         (k_prio_t)(TOS_CFG_TASK_PRIO_MAX - (k_prio_t)1u)
#define K_TASK_PRIO_INVALID      (k_prio_t)(TOS_CFG_TASK_PRIO_MAX)

// ready to schedule
// a task's pend_list is in readyqueue
#define K_TASK_STATE_READY                (k_task_state_t)0x0000

// delayed, or pend for a timeout
// a task's tick_list is in k_tick_list
#define K_TASK_STATE_SLEEP                (k_task_state_t)0x0001

// pend for something
// a task's pend_list is in some pend object's list
#define K_TASK_STATE_PEND                 (k_task_state_t)0x0002

// suspended
#define K_TASK_STATE_SUSPENDED            (k_task_state_t)0x0004

// deleted
#define K_TASK_STATE_DELETED              (k_task_state_t)0x0008

// we are pending, also we are waitting for a timeout(eg. tos_sem_pend with a valid timeout, not TOS_TIME_FOREVER)
// both a task's tick_list and pend_list is not empty
#define K_TASK_STATE_PENDTIMEOUT                      (k_task_state_t)(K_TASK_STATE_PEND | K_TASK_STATE_SLEEP)

// suspended when sleeping
#define K_TASK_STATE_SLEEP_SUSPENDED                  (k_task_state_t)(K_TASK_STATE_SLEEP | K_TASK_STATE_SUSPENDED)

// suspened when pending
#define K_TASK_STATE_PEND_SUSPENDED                   (k_task_state_t)(K_TASK_STATE_PEND | K_TASK_STATE_SUSPENDED)

// suspended when pendtimeout
#define K_TASK_STATE_PENDTIMEOUT_SUSPENDED            (k_task_state_t)(K_TASK_STATE_PENDTIMEOUT | K_TASK_STATE_SUSPENDED)

readyqueue_t        k_rdyq;

typedef struct readyqueue_st {
    k_list_t    task_list_head[TOS_CFG_TASK_PRIO_MAX];
    uint32_t    prio_mask[K_PRIO_TBL_SIZE];
    k_prio_t    highest_prio;
} readyqueue_t;

#define K_PRIO_TBL_SIZE         ((TOS_CFG_TASK_PRIO_MAX + 31) / 32)

k_list_t             k_tick_list;

typedef struct k_task_st {
    k_stack_t          *sp;                 /**< 任务栈指针,用于切换上下文*/

#if TOS_CFG_OBJECT_VERIFY_EN > 0u
    knl_obj_t           knl_obj;            /**< 只是为了验证，测试当前对象是否真的是一项任务。*/
#endif

    char               *name;               /**< 任务名称 */
    k_task_entry_t      entry;              /**< 任务主体 */
    void               *arg;                /**< 任务主体形参 */
    k_task_state_t      state;              /**< 任务状态 */
    k_prio_t            prio;               /**< 任务优先级 */

    k_stack_t          *stk_base;           /**< 任务栈基地址 */
    size_t              stk_size;           /**< 任务栈大小 */

    k_tick_t            tick_expires;       /**< 任务阻塞的时间 */

    k_list_t            tick_list;          /**< 延时列表 */
    k_list_t            pend_list;          /**< 等待列表 */

#if TOS_CFG_MUTEX_EN > 0u
    k_list_t            mutex_own_list;     /**< 任务拥有的互斥量 */
    k_prio_t            prio_pending;       /*< 用于记录持有互斥量的任务初始优先级，在优先级继承中使用 */
#endif

    pend_obj_t         *pending_obj;       /**< 等待的对象 */
    pend_state_t        pend_state;         /**< 等待被唤醒的原因（状态） */

#if TOS_CFG_ROUND_ROBIN_EN > 0u
    k_timeslice_t       timeslice_reload;   /**< 时间片初始值（重装载值） */
    k_timeslice_t       timeslice;          /**< 剩余时间片 */
#endif

#if TOS_CFG_MSG_EN > 0u
    void               *msg_addr;           /**< 保存接收到的消息 */
    size_t              msg_size;            /**< 保存接收到的消息大小 */
#endif

#if TOS_CFG_EVENT_EN > 0u
    k_opt_t             opt_event_pend;     /**< 等待事件的的操作类型：TOS_OPT_EVENT_PEND_ANY 、 TOS_OPT_EVENT_PEND_ALL */
    k_event_flag_t      flag_expect;        /**< 期待发生的事件 */
    k_event_flag_t     *flag_match;         /**< 等待到的事件 */
#endif
} k_task_t;

__API__ k_err_t tos_task_create(k_task_t *task,
                                char *name,
                                k_task_entry_t entry,
                                void *arg,
                                k_prio_t prio,
                                k_stack_t *stk_base,
                                size_t stk_size,
                                k_timeslice_t timeslice)
{
    TOS_CPU_CPSR_ALLOC();

    TOS_IN_IRQ_CHECK();

    TOS_PTR_SANITY_CHECK(task);
    TOS_PTR_SANITY_CHECK(entry);
    TOS_PTR_SANITY_CHECK(stk_base);

    if (unlikely(stk_size < sizeof(cpu_context_t))) {
        return K_ERR_TASK_STK_SIZE_INVALID;
    }

    if (unlikely(prio == K_TASK_PRIO_IDLE && !knl_is_idle(task))) {
        return K_ERR_TASK_PRIO_INVALID;
    }

    if (unlikely(prio > K_TASK_PRIO_IDLE)) {
        return K_ERR_TASK_PRIO_INVALID;
    }

    task_reset(task);
#if TOS_CFG_OBJECT_VERIFY_EN > 0u
    knl_object_init(&task->knl_obj, KNL_OBJ_TYPE_TASK);
#endif

    task->sp        = cpu_task_stk_init((void *)entry, arg, (void *)task_exit, stk_base, stk_size);
    task->entry     = entry;
    task->arg       = arg;
    task->name      = name;
    task->prio      = prio;
    task->stk_base  = stk_base;
    task->stk_size  = stk_size;

#if TOS_CFG_ROUND_ROBIN_EN > 0u
    task->timeslice_reload = timeslice;

    if (timeslice == (k_timeslice_t)0u) {
        task->timeslice = k_robin_default_timeslice;
    } else {
        task->timeslice = timeslice;
    }
#endif

    TOS_CPU_INT_DISABLE();
    task_state_set_ready(task);
    readyqueue_add_tail(task);
    TOS_CPU_INT_ENABLE();

    if (tos_knl_is_running()) {
        knl_sched();
    }

    return K_ERR_NONE;
}

__API__ k_err_t tos_task_destroy(k_task_t *task)
{
    TOS_CPU_CPSR_ALLOC();

    TOS_IN_IRQ_CHECK();

    if (unlikely(!task)) {
        task = k_curr_task;
    }

#if TOS_CFG_OBJECT_VERIFY_EN > 0u
    if (!knl_object_verify(&task->knl_obj, KNL_OBJ_TYPE_TASK)) {
        return K_ERR_OBJ_INVALID;
    }
#endif

    if (knl_is_idle(task)) {
        return K_ERR_TASK_DESTROY_IDLE;
    }

    if (knl_is_self(task) && knl_is_sched_locked()) {
        return K_ERR_SCHED_LOCKED;
    }

    TOS_CPU_INT_DISABLE();

#if TOS_CFG_MUTEX_EN > 0u
    // when we die, wakeup all the people in this land.
    if (!tos_list_empty(&task->mutex_own_list)) {
        task_mutex_release(task);
    }
#endif

    if (task_state_is_ready(task)) { // that's simple, good kid
        readyqueue_remove(task);
    }
    if (task_state_is_sleeping(task)) {
        tick_list_remove(task);
    }
    if (task_state_is_pending(task)) {
        pend_list_remove(task);
    }

    task_reset(task);
    task_state_set_deleted(task);

    TOS_CPU_INT_ENABLE();
    knl_sched();

    return K_ERR_NONE;
}

__API__ k_err_t tos_task_delay(k_tick_t delay)
{
    TOS_CPU_CPSR_ALLOC();

    TOS_IN_IRQ_CHECK();

    if (knl_is_sched_locked()) {
        return K_ERR_SCHED_LOCKED;
    }

    if (unlikely(delay == (k_tick_t)0u)) {
        tos_task_yield();
        return K_ERR_NONE;
    }

    TOS_CPU_INT_DISABLE();

    if (tick_list_add(k_curr_task, delay) != K_ERR_NONE) {
        TOS_CPU_INT_ENABLE();
        return K_ERR_DELAY_FOREVER;
    }

    readyqueue_remove(k_curr_task);

    TOS_CPU_INT_ENABLE();
    knl_sched();

    return K_ERR_NONE;
}