RT-thread can 接收数据无法拷贝读取rt_device_read(candev, ...

发布于 2019-06-06 16:44:02 浏览：2133 订阅该版

RT-thread CAN  提供的驱动文包含 can.c  drv_can.c

drv_can.c 中
  /* save to user fifo */
        rt_hw_can_isr(&dev_can1, RT_CAN_EVENT_RX_IND | 0 << 8);
can 进行debug 调试发现
调用在文件  can.c  中

void rt_hw_can_isr(struct rt_can_device *can, int event)
{
    switch (event & 0xff)
    {
    case RT_CAN_EVENT_RXOF_IND:
    {
        rt_base_t level;
        level = rt_hw_interrupt_disable();
        can->status.dropedrcvpkg++;
        rt_hw_interrupt_enable(level);
    }
 case RT_CAN_EVENT_RX_IND:
    {
        struct rt_can_msg tmpmsg;
        struct rt_can_rx_fifo *rx_fifo;
        struct rt_can_msg_list *listmsg = RT_NULL;
#ifdef RT_CAN_USING_HDR
        rt_int8_t hdr;
#endif
        int ch = -1;
        rt_base_t level;
        rt_uint32_t no;

rx_fifo = (struct rt_can_rx_fifo *)can->can_rx;
        RT_ASSERT(rx_fifo != RT_NULL);
        /* interrupt mode receive */
        RT_ASSERT(can->parent.open_flag & RT_DEVICE_FLAG_INT_RX);

no = event >> 8;
        ch = can->ops->recvmsg(can, &tmpmsg, no);这里可以成功的 将can寄存器中的数据  拷贝到tmpmsg 中
        if (ch == -1) break;

/* disable interrupt */
        level = rt_hw_interrupt_disable();
        can->status.rcvpkg++;
        can->status.rcvchange = 1;//  下面的代码 就看不懂了  有链表的操作指导教材吗？
        if (!rt_list_isempty(&rx_fifo->freelist))
        {
            listmsg = rt_list_entry(rx_fifo->freelist.next, struct rt_can_msg_list, list);
            rt_list_remove(&listmsg->list);
#ifdef RT_CAN_USING_HDR
            rt_list_remove(&listmsg->hdrlist);
            if (listmsg->owner != RT_NULL && listmsg->owner->msgs)
            {
                listmsg->owner->msgs--;
            }
            listmsg->owner = RT_NULL;
#endif /*RT_CAN_USING_HDR*/
            RT_ASSERT(rx_fifo->freenumbers > 0);
            rx_fifo->freenumbers--;
        }
        else if (!rt_list_isempty(&rx_fifo->uselist))
        {
            listmsg = rt_list_entry(rx_fifo->uselist.next, struct rt_can_msg_list, list);
            can->status.dropedrcvpkg++;
            rt_list_remove(&listmsg->list);
#ifdef RT_CAN_USING_HDR
            rt_list_remove(&listmsg->hdrlist);
            if (listmsg->owner != RT_NULL && listmsg->owner->msgs)
            {
                listmsg->owner->msgs--;
            }
            listmsg->owner = RT_NULL;
#endif
        }
        /* enable interrupt */
        rt_hw_interrupt_enable(level);

if (listmsg != RT_NULL)
        {
            rt_memcpy(&listmsg->data, &tmpmsg, sizeof(struct rt_can_msg));//  这里拷贝can 接受到数据 到listmsg 没有执行
            level = rt_hw_interrupt_disable();
            rt_list_insert_before(&rx_fifo->uselist, &listmsg->list);
#ifdef RT_CAN_USING_HDR
            hdr = tmpmsg.hdr;
            if (can->hdr != RT_NULL)
            {
                RT_ASSERT(hdr < can->config.maxhdr && hdr >= 0);
                if (can->hdr[hdr].connected)
                {
                    rt_list_insert_before(&can->hdr[hdr].list, &listmsg->hdrlist);
                    listmsg->owner = &can->hdr[hdr];
                    can->hdr[hdr].msgs++;
                }

}
#endif
            rt_hw_interrupt_enable(level);
        }

/* invoke callback */
#ifdef RT_CAN_USING_HDR
        if (can->hdr != RT_NULL && can->hdr[hdr].connected && can->hdr[hdr].filter.ind)
        {
            rt_size_t rx_length;
            RT_ASSERT(hdr < can->config.maxhdr && hdr >= 0);

level = rt_hw_interrupt_disable();
            rx_length = can->hdr[hdr].msgs * sizeof(struct rt_can_msg);
            rt_hw_interrupt_enable(level);
            can->hdr[hdr].filter.ind(&can->parent, can->hdr[hdr].filter.args, hdr, rx_length);
        }
        else
#endif
        {
            if (can->parent.rx_indicate != RT_NULL)
            {
                rt_size_t rx_length;

level = rt_hw_interrupt_disable();
                /* get rx length */
                rx_length = rt_list_len(&rx_fifo->uselist)* sizeof(struct rt_can_msg);
                rt_hw_interrupt_enable(level);

can->parent.rx_indicate(&can->parent, rx_length);
            }
        }
        break;
    }

代码中 提及了HDR  我需要这块的操作说明  如何初始化？