请写出stm32用hal库实现基于dma的串口通信的代码

以下是基于DMA的STM32串口通信的HAL库实现代码：

#include "stm32f4xx_hal.h"

UART_HandleTypeDef huart;

void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(uartHandle->Instance==USART1)
  {
    /* USART1 clock enable */
    __HAL_RCC_USART1_CLK_ENABLE();
  
    __HAL_RCC_GPIOA_CLK_ENABLE();
    /**USART1 GPIO Configuration    
    PA9     ------> USART1_TX
    PA10     ------> USART1_RX 
    */
    GPIO_InitStruct.Pin = GPIO_PIN_9|GPIO_PIN_10;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    /* USART1 DMA Init */
    /* USART1_TX Init */
    hdma_usart1_tx.Instance = DMA2_Stream7;
    hdma_usart1_tx.Init.Channel = DMA_CHANNEL_4;
    hdma_usart1_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
    hdma_usart1_tx.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_usart1_tx.Init.MemInc = DMA_MINC_ENABLE;
    hdma_usart1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_usart1_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_usart1_tx.Init.Mode = DMA_NORMAL;
    hdma_usart1_tx.Init.Priority = DMA_PRIORITY_LOW;
    hdma_usart1_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
    if (HAL_DMA_Init(&hdma_usart1_tx) != HAL_OK)
    {
      Error_Handler();
    }

    __HAL_LINKDMA(uartHandle,hdmatx,hdma_usart1_tx);

    /* USART1_RX Init */
    hdma_usart1_rx.Instance = DMA2_Stream2;
    hdma_usart1_rx.Init.Channel = DMA_CHANNEL_4;
    hdma_usart1_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_usart1_rx.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_usart1_rx.Init.MemInc = DMA_MINC_ENABLE;
    hdma_usart1_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_usart1_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_usart1_rx.Init.Mode = DMA_CIRCULAR;
    hdma_usart1_rx.Init.Priority = DMA_PRIORITY_LOW;
    hdma_usart1_rx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
    if (HAL_DMA_Init(&hdma_usart1_rx) != HAL_OK)
    {
      Error_Handler();
    }

    __HAL_LINKDMA(uartHandle,hdmarx,hdma_usart1_rx);
  }
}

void HAL_UART_MspDeInit(UART_HandleTypeDef* uartHandle)
{
  if(uartHandle->Instance==USART1)
  {
    /* Peripheral clock disable */
    __HAL_RCC_USART1_CLK_DISABLE();
  
    /**USART1 GPIO Configuration    
    PA9     ------> USART1_TX
    PA10     ------> USART1_RX 
    */
    HAL_GPIO_DeInit(GPIOA, GPIO_PIN_9|GPIO_PIN_10);

    /* USART1 DMA DeInit */
    HAL_DMA_DeInit(uartHandle->hdmatx);
    HAL_DMA_DeInit(uartHandle->hdmarx);
  }
}

void MX_USART1_UART_Init(void)
{

  huart.Instance = USART1;
  huart.Init.BaudRate = 115200;
  huart.Init.WordLength = UART_WORDLENGTH_8B;
  huart.Init.StopBits = UART_STOPBITS_1;
  huart.Init.Parity = UART_PARITY_NONE;
  huart.Init.Mode = UART_MODE_TX_RX;
  huart.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart) != HAL_OK)
  {
    Error_Handler();
  }

}

这段代码使用了HAL库实现了基于DMA的串口通信。在这个例子中，我们使用了USART1作为串口，使用了DMA2的Stream7和Stream2作为发送和接收的DMA通道。在初始化函数中，我们设置了串口的波特率、数据位、停止位、校验位等参数，并且初始化了DMA通道。在使用串口进行通信时，我们可以使用HAL库提供的函数来发送和接收数据，例如：

HAL_UART_Transmit_DMA(&huart, (uint8_t*)tx_buffer, tx_len);
HAL_UART_Receive_DMA(&huart, (uint8_t*)rx_buffer, rx_len);

这两个函数分别使用DMA通道发送和接收数据，可以大大提高串口通信的效率。