Function _serial_dma_rx

components/drivers/serial/dev_serial.c:523–578

* Serial DMA routines */

 * Serial DMA routines
 */
rt_inline int _serial_dma_rx(struct rt_serial_device *serial, rt_uint8_t *data, int length)
{
    rt_base_t level;

    RT_ASSERT((serial != RT_NULL) && (data != RT_NULL));

    level = rt_spin_lock_irqsave(&(serial->spinlock));

    if (serial->config.bufsz == 0)
    {
        int result = RT_EOK;
        struct rt_serial_rx_dma *rx_dma;

        rx_dma = (struct rt_serial_rx_dma*)serial->serial_rx;
        RT_ASSERT(rx_dma != RT_NULL);

        if (rx_dma->activated != RT_TRUE)
        {
            rx_dma->activated = RT_TRUE;
            RT_ASSERT(serial->ops->dma_transmit != RT_NULL);
            serial->ops->dma_transmit(serial, data, length, RT_SERIAL_DMA_RX);
        }
        else result = -RT_EBUSY;
        rt_spin_unlock_irqrestore(&(serial->spinlock), level);

        if (result == RT_EOK) return length;

        rt_set_errno(result);
        return 0;
    }
    else
    {
        struct rt_serial_rx_fifo *rx_fifo = (struct rt_serial_rx_fifo *) serial->serial_rx;
        rt_size_t recv_len = 0, fifo_recved_len = rt_dma_calc_recved_len(serial);

        RT_ASSERT(rx_fifo != RT_NULL);

        if (length < (int)fifo_recved_len)
            recv_len = length;
        else
            recv_len = fifo_recved_len;

        if (rx_fifo->get_index + recv_len < serial->config.bufsz)
            rt_memcpy(data, rx_fifo->buffer + rx_fifo->get_index, recv_len);
        else
        {
            rt_memcpy(data, rx_fifo->buffer + rx_fifo->get_index,
                    serial->config.bufsz - rx_fifo->get_index);
            rt_memcpy(data + serial->config.bufsz - rx_fifo->get_index, rx_fifo->buffer,
                    recv_len + rx_fifo->get_index - serial->config.bufsz);
        }
        rt_dma_recv_update_get_index(serial, recv_len);
        rt_spin_unlock_irqrestore(&(serial->spinlock), level);
        return recv_len;
    }
}

rt_inline int _serial_dma_tx(struct rt_serial_device *serial, const rt_uint8_t *data, int length)