rt_can_write内_can_int_tx死循环

发布于 2020-07-20 14:02:36 浏览：1824 订阅该版

环境：stm32f407 时钟频率168M CAN波特率1M
can配置如下：
```c
    drv_can->CanHandle.Init.TimeTriggeredMode = DISABLE;
    drv_can->CanHandle.Init.AutoBusOff = ENABLE;
    drv_can->CanHandle.Init.AutoWakeUp = DISABLE;
    drv_can->CanHandle.Init.AutoRetransmission = DISABLE;
    drv_can->CanHandle.Init.ReceiveFifoLocked = DISABLE;
    drv_can->CanHandle.Init.TransmitFifoPriority = ENABLE;
```
问题：
接了can设备时，使用正常
开发板拔掉can总线线后，或can设备不通电时，一直在这个函数内死循环。
```c
rt_inline int _can_int_tx(struct rt_can_device *can, const struct rt_can_msg *data, int msgs)
{
    int size;
    struct rt_can_tx_fifo *tx_fifo;

RT_ASSERT(can != RT_NULL);

size = msgs;
    tx_fifo = (struct rt_can_tx_fifo *) can->can_tx;
    RT_ASSERT(tx_fifo != RT_NULL);

while (msgs)
    {
        rt_base_t level;
        rt_uint32_t no;
        rt_uint32_t result;
        struct rt_can_sndbxinx_list *tx_tosnd = RT_NULL;

rt_sem_take(&(tx_fifo->sem), RT_WAITING_FOREVER);
        level = rt_hw_interrupt_disable();
        tx_tosnd = rt_list_entry(tx_fifo->freelist.next, struct rt_can_sndbxinx_list, list);
        RT_ASSERT(tx_tosnd != RT_NULL);
        rt_list_remove(&tx_tosnd->list);
        rt_hw_interrupt_enable(level);

no = ((rt_uint32_t)tx_tosnd - (rt_uint32_t)tx_fifo->buffer) / sizeof(struct rt_can_sndbxinx_list);
        tx_tosnd->result = RT_CAN_SND_RESULT_WAIT;
        if (can->ops->sendmsg(can, data, no) != RT_EOK)
        {//一直进入此条件内

/* send failed. */
            level = rt_hw_interrupt_disable();
            rt_list_insert_after(&tx_fifo->freelist, &tx_tosnd->list);
            rt_hw_interrupt_enable(level);
            rt_sem_release(&(tx_fifo->sem));

continue;
        }

can->status.sndchange = 1;
        rt_completion_wait(&(tx_tosnd->completion), RT_WAITING_FOREVER);

level = rt_hw_interrupt_disable();
        result = tx_tosnd->result;
        if (!rt_list_isempty(&tx_tosnd->list))
        {
            rt_list_remove(&tx_tosnd->list);
        }
        rt_list_insert_before(&tx_fifo->freelist, &tx_tosnd->list);
        rt_hw_interrupt_enable(level);
        rt_sem_release(&(tx_fifo->sem));

if (result == RT_CAN_SND_RESULT_OK)
        {
            level = rt_hw_interrupt_disable();
            can->status.sndpkg++;
            rt_hw_interrupt_enable(level);

data ++;
            msgs -= sizeof(struct rt_can_msg);
            if (!msgs) break;
        }
        else
        {
            level = rt_hw_interrupt_disable();
            can->status.dropedsndpkg++;
            rt_hw_interrupt_enable(level);
            break;
        }
    }

return (size - msgs);
}
```