rt-thread/components/drivers/src/dataqueue.c

/*
 * File      : dataqueue.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 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
 * 2012-09-30     Bernard      first version.
 */

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

struct rt_data_item
{
    const void *data_ptr;
    rt_size_t data_size;
};

rt_err_t
rt_data_queue_init(struct rt_data_queue *queue,
                   rt_uint16_t size,
                   rt_uint16_t lwm,
                   void (*evt_notify)(struct rt_data_queue *queue, rt_uint32_t event))
{
    RT_ASSERT(queue != RT_NULL);

    queue->evt_notify = evt_notify;

    queue->size = size;
    queue->lwm = lwm;
    queue->waiting_lwm = RT_FALSE;

    queue->get_index = 0;
    queue->put_index = 0;

    rt_list_init(&(queue->suspended_push_list));
    rt_list_init(&(queue->suspended_pop_list));

    queue->queue = (struct rt_data_item *)rt_malloc(sizeof(struct rt_data_item) * size);
    if (queue->queue == RT_NULL)
    {
        return -RT_ENOMEM;
    }

    return RT_EOK;
}
RTM_EXPORT(rt_data_queue_init);

rt_err_t rt_data_queue_push(struct rt_data_queue *queue,
                            const void *data_ptr,
                            rt_size_t data_size,
                            rt_int32_t timeout)
{
    rt_uint16_t mask;
    rt_ubase_t  level;
    rt_thread_t thread;
    rt_err_t    result;
    
    RT_ASSERT(queue != RT_NULL);

    result = RT_EOK;
    thread = rt_thread_self();
    mask = queue->size - 1;

    level = rt_hw_interrupt_disable();
    while (queue->put_index - queue->get_index == queue->size)
    {
        queue->waiting_lwm = RT_TRUE;

        /* queue is full */
        if (timeout == 0)
        {
            result = -RT_ETIMEOUT;

            goto __exit;
        }

        /* current context checking */
        RT_DEBUG_NOT_IN_INTERRUPT;

        /* reset thread error number */
        thread->error = RT_EOK;
        
        /* suspend thread on the push list */
        rt_thread_suspend(thread);
        rt_list_insert_before(&(queue->suspended_push_list), &(thread->tlist));
        /* start timer */
        if (timeout > 0)
        {
            /* reset the timeout of thread timer and start it */
            rt_timer_control(&(thread->thread_timer), RT_TIMER_CTRL_SET_TIME, &timeout);
            rt_timer_start(&(thread->thread_timer));
        }

        /* enable interrupt */
        rt_hw_interrupt_enable(level);

        /* do schedule */
        rt_schedule();

        /* thread is waked up */
        result = thread->error;
        level = rt_hw_interrupt_disable();
        if (result != RT_EOK) goto __exit;
    }

    queue->queue[queue->put_index & mask].data_ptr  = data_ptr;
    queue->queue[queue->put_index & mask].data_size = data_size;
    queue->put_index += 1;

    if (!rt_list_isempty(&(queue->suspended_pop_list)))
    {
        /* there is at least one thread in suspended list */

        /* get thread entry */
        thread = rt_list_entry(queue->suspended_pop_list.next, struct rt_thread, tlist);

        /* resume it */
        rt_thread_resume(thread);
        rt_hw_interrupt_enable(level);

        /* perform a schedule */
        rt_schedule();

        return result;
    }

__exit:
    rt_hw_interrupt_enable(level);
    if ((result == RT_EOK) && queue->evt_notify != RT_NULL)
    {
        queue->evt_notify(queue, RT_DATAQUEUE_EVENT_PUSH);
    }

    return result;
}
RTM_EXPORT(rt_data_queue_push);

rt_err_t rt_data_queue_pop(struct rt_data_queue *queue,
                           const void** data_ptr,
                           rt_size_t *size, 
                           rt_int32_t timeout)
{
    rt_ubase_t  level;
    rt_thread_t thread;
    rt_err_t    result;
    rt_uint16_t mask;

    RT_ASSERT(queue != RT_NULL);
    RT_ASSERT(data_ptr != RT_NULL);
    RT_ASSERT(size != RT_NULL);

    result = RT_EOK;
    thread = rt_thread_self();
    mask = queue->size - 1;

    level = rt_hw_interrupt_disable();
    while (queue->get_index == queue->put_index)
    {
        /* queue is empty */
        if (timeout == 0)
        {
            result = -RT_ETIMEOUT;
            goto __exit;
        }

        /* current context checking */
        RT_DEBUG_NOT_IN_INTERRUPT;

        /* reset thread error number */
        thread->error = RT_EOK;
        
        /* suspend thread on the pop list */
        rt_thread_suspend(thread);
        rt_list_insert_before(&(queue->suspended_pop_list), &(thread->tlist));
        /* start timer */
        if (timeout > 0)
        {
            /* reset the timeout of thread timer and start it */
            rt_timer_control(&(thread->thread_timer), RT_TIMER_CTRL_SET_TIME, &timeout);
            rt_timer_start(&(thread->thread_timer));
        }

        /* enable interrupt */
        rt_hw_interrupt_enable(level);

        /* do schedule */
        rt_schedule();

        /* thread is waked up */
        result = thread->error;
        level = rt_hw_interrupt_disable();
        if (result != RT_EOK) goto __exit;
    }

    *data_ptr = queue->queue[queue->get_index & mask].data_ptr;
    *size     = queue->queue[queue->get_index & mask].data_size;

    queue->get_index += 1;

    if ((queue->waiting_lwm == RT_TRUE) && 
        (queue->put_index - queue->get_index) <= queue->lwm)
    {
        queue->waiting_lwm = RT_FALSE;

        /* there is at least one thread in suspended list and less than low water mark */
        if (!rt_list_isempty(&(queue->suspended_push_list)))
        {
            /* get thread entry */
            thread = rt_list_entry(queue->suspended_push_list.next, struct rt_thread, tlist);

            /* resume it */
            rt_thread_resume(thread);
            rt_hw_interrupt_enable(level);

            /* perform a schedule */
            rt_schedule();
        }

        if (queue->evt_notify != RT_NULL)
            queue->evt_notify(queue, RT_DATAQUEUE_EVENT_LWM);

        return result;
    }

__exit:
    rt_hw_interrupt_enable(level);
    if ((result == RT_EOK) && (queue->evt_notify != RT_NULL))
    {
        queue->evt_notify(queue, RT_DATAQUEUE_EVENT_POP);
    }

    return result;
}
RTM_EXPORT(rt_data_queue_pop);

rt_err_t rt_data_queue_peak(struct rt_data_queue *queue,
                            const void** data_ptr,
                            rt_size_t *size)
{
    rt_ubase_t  level;
    rt_uint16_t mask;

    RT_ASSERT(queue != RT_NULL);

    mask = queue->size - 1;

    level = rt_hw_interrupt_disable();

    if (queue->get_index == queue->put_index) 
    {
        rt_hw_interrupt_enable(level);
        
        return -RT_EEMPTY;
    }

    *data_ptr = queue->queue[queue->get_index & mask].data_ptr;
    *size     = queue->queue[queue->get_index & mask].data_size;

    rt_hw_interrupt_enable(level);

    return RT_EOK;
}
RTM_EXPORT(rt_data_queue_peak);

void rt_data_queue_reset(struct rt_data_queue *queue)
{
    struct rt_thread *thread;
    register rt_ubase_t temp;

    rt_enter_critical();
    /* wakeup all suspend threads */

    /* resume on pop list */
    while (!rt_list_isempty(&(queue->suspended_pop_list)))
    {
        /* disable interrupt */
        temp = rt_hw_interrupt_disable();

        /* get next suspend thread */
        thread = rt_list_entry(queue->suspended_pop_list.next, struct rt_thread, tlist);
        /* set error code to RT_ERROR */
        thread->error = -RT_ERROR;

        /*
         * resume thread
         * In rt_thread_resume function, it will remove current thread from
         * suspend list
         */
        rt_thread_resume(thread);

        /* enable interrupt */
        rt_hw_interrupt_enable(temp);
    }

    /* resume on push list */
    while (!rt_list_isempty(&(queue->suspended_push_list)))
    {
        /* disable interrupt */
        temp = rt_hw_interrupt_disable();

        /* get next suspend thread */
        thread = rt_list_entry(queue->suspended_push_list.next, struct rt_thread, tlist);
        /* set error code to RT_ERROR */
        thread->error = -RT_ERROR;

        /*
         * resume thread
         * In rt_thread_resume function, it will remove current thread from
         * suspend list
         */
        rt_thread_resume(thread);

        /* enable interrupt */
        rt_hw_interrupt_enable(temp);
    }
    rt_exit_critical();

    rt_schedule();
}
RTM_EXPORT(rt_data_queue_reset);