Function rt_mq_init

src/ipc.c:3097–3156

* @brief Initialize a static messagequeue object. * * @note For the static messagequeue object, its memory space is allocated by the compiler during compiling, * and shall placed on the read-write data segment or on the uninitialized data segment. * By contrast, the rt_mq_create() function will allocate memory space automatically * and initialize the messa

 * @warning  This function can ONLY be called from threads.
 */
rt_err_t rt_mq_init(rt_mq_t     mq,
                    const char *name,
                    void       *msgpool,
                    rt_size_t   msg_size,
                    rt_size_t   pool_size,
                    rt_uint8_t  flag)
{
    struct rt_mq_message *head;
    rt_base_t temp;
    register rt_size_t msg_align_size;

    /* parameter check */
    RT_ASSERT(mq != RT_NULL);
    RT_ASSERT((flag == RT_IPC_FLAG_FIFO) || (flag == RT_IPC_FLAG_PRIO));

    /* initialize object */
    rt_object_init(&(mq->parent.parent), RT_Object_Class_MessageQueue, name);

    /* set parent flag */
    mq->parent.parent.flag = flag;

    /* initialize ipc object */
    _ipc_object_init(&(mq->parent));

    /* set message pool */
    mq->msg_pool = msgpool;

    /* get correct message size */
    msg_align_size = RT_ALIGN(msg_size, RT_ALIGN_SIZE);
    mq->msg_size = msg_size;
    mq->max_msgs = pool_size / (msg_align_size + sizeof(struct rt_mq_message));

    if (0 == mq->max_msgs)
    {
        return -RT_EINVAL;
    }

    /* initialize message list */
    mq->msg_queue_head = RT_NULL;
    mq->msg_queue_tail = RT_NULL;

    /* initialize message empty list */
    mq->msg_queue_free = RT_NULL;
    for (temp = 0; temp < mq->max_msgs; temp ++)
    {
        head = (struct rt_mq_message *)((rt_uint8_t *)mq->msg_pool +
                                        temp * (msg_align_size + sizeof(struct rt_mq_message)));
        head->next = (struct rt_mq_message *)mq->msg_queue_free;
        mq->msg_queue_free = head;
    }

    /* the initial entry is zero */
    mq->entry = 0;

    /* initialize an additional list of sender suspend thread */
    rt_list_init(&(mq->suspend_sender_thread));
    rt_spin_lock_init(&(mq->spinlock));