rt-thread移植finSH控制台中STM32 HAL库的缺陷

小小的一个串口居然看了半天，原来对STM32系列的lib库，好像是1.x版本感觉还不错的。后来ST非要整个CUBEMx库，往一个中断接受函数里丢了一堆东西。
在rt-thread官网中给出了nano版本增加控制台的示范例程，主要是增加了一个接受队列。(如果用rt-thread studio配置控制台，接受好像用的是查询模式，如果只是单纯一个控制台，不干其他事情好像也没啥事)

#ifdef RT_USING_FINSH
char rt_hw_console_getchar(void)
{
    int ch = -1;

    if (__HAL_UART_GET_FLAG(&handle, UART_FLAG_RXNE) != RESET)
    {
#if defined(SOC_SERIES_STM32L4) || defined(SOC_SERIES_STM32F7) || defined(SOC_SERIES_STM32F0) \
    || defined(SOC_SERIES_STM32L0) || defined(SOC_SERIES_STM32G0) || defined(SOC_SERIES_STM32H7) \
    || defined(SOC_SERIES_STM32G4)
        ch = handle.Instance->RDR & 0xff;
#else
        ch = handle.Instance->DR & 0xff;
#endif
    }
    else
    {
        if(__HAL_UART_GET_FLAG(&handle, UART_FLAG_ORE) != RESET)
        {
            __HAL_UART_CLEAR_OREFLAG(&handle);
        }
        rt_thread_mdelay(10);
    }
    return ch;
}

用中断模式+接受队列接受大量数据可能会更健壮可靠些。问题是实验了几次，只要在串口助手中发送了2个字节，中断接受就出现问题，再也进入不了中断函数了。后来关闭了控制台的echo回应功能，居然神奇的好了。

    /* normal is echo mode */
#ifndef FINSH_ECHO_DISABLE_DEFAULT
    shell->echo_mode = 1;
#else
    shell->echo_mode = 0;
#endif

多半定位到是串口发送导致的。原来这是ST的HAL库的bug，在串口发送中进行了互斥操作，导致有接受中断时不能再次启动接受中断。如下

/**
  * @brief  Sends an amount of data in blocking mode.
  * @note   When UART parity is not enabled (PCE = 0), and Word Length is configured to 9 bits (M1-M0 = 01),
  *         the sent data is handled as a set of u16. In this case, Size must indicate the number
  *         of u16 provided through pData.
  * @param  huart Pointer to a UART_HandleTypeDef structure that contains
  *               the configuration information for the specified UART module.
  * @param  pData Pointer to data buffer (u8 or u16 data elements).
  * @param  Size  Amount of data elements (u8 or u16) to be sent
  * @param  Timeout Timeout duration
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_UART_Transmit(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size, uint32_t Timeout)
{
  uint16_t *tmp;
  uint32_t tickstart = 0U;

  /* Check that a Tx process is not already ongoing */
  if (huart->gState == HAL_UART_STATE_READY)
  {
    if ((pData == NULL) || (Size == 0U))
    {
      return  HAL_ERROR;
    }

    /* Process Locked */
    __HAL_LOCK(huart);


   ....
   ....


    /* At end of Tx process, restore huart->gState to Ready */
    huart->gState = HAL_UART_STATE_READY;

    /* Process Unlocked */
    __HAL_UNLOCK(huart);

国外论坛也有这个讨论
[https://community.st.com/s/question/0D50X00009XkeOGSAZ/questions-surrounding-hallock]

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
...


        __HAL_UNLOCK(&HUART);   
...
    }
}

在中断回调函数中加入个unlock就好了。
当时是注意到RTT官方的文档中断发送函数中有unlock操作，看来接受也得加个

/* 移植控制台，实现控制台输出, 对接 rt_hw_console_output */
void rt_hw_console_output(const char *str)
{
    rt_size_t i = 0, size = 0;
    char a = '\r';

    __HAL_UNLOCK(&HUART);

    size = rt_strlen(str);
    for (i = 0; i < size; i++)
    {
        if (*(str + i) == '\n')
        {
            HAL_UART_Transmit(&HUART, (uint8_t *)&a, 1, 1);
        }
        HAL_UART_Transmit(&HUART, (uint8_t *)(str + i), 1, 1);
    }
}