Function serial_fops_read

components/drivers/serial/dev_serial_v2.c:145–179

static ssize_t serial_fops_read(struct dfs_file *fd, void *buf, size_t count, off_t *pos)
#else
static ssize_t serial_fops_read(struct dfs_file *fd, void *buf, size_t count)
#endif
{
    ssize_t     size = 0;
    rt_device_t device;
    rt_int32_t  rx_timout;

    if (count == 0) return 0;
    RT_ASSERT(fd != RT_NULL && buf != RT_NULL);

    device = (rt_device_t)fd->vnode->data;
    RT_ASSERT(device != RT_NULL);

    /* nonblock mode */
    if (fd->flags & O_NONBLOCK)
    {
        rx_timout = RT_WAITING_NO;
        rt_device_control(device, RT_SERIAL_CTRL_SET_RX_TIMEOUT, (void *)&rx_timout);
        size = rt_device_read(device, -1, buf, count);
        if (size <= 0)
        {
            size = -1;
            rt_set_errno(EAGAIN);
        }
    }
    else
    {
        rx_timout = RT_WAITING_FOREVER;
        rt_device_control(device, RT_SERIAL_CTRL_SET_RX_TIMEOUT, (void *)&rx_timout);
        size = rt_device_read(device, -1, buf, count);
    }


    return size;
}

#ifdef RT_USING_DFS_V2
static ssize_t serial_fops_write(struct dfs_file *fd, const void *buf, size_t count, off_t *pos)