STM32F103使用串口DMA收发数据的源码该怎样去实现呢

u8 gprsTxBuf[100];
u8 gprsRxBuf[1500];
//接收DMA初始化
void tx_dma_init(void)
{
        DMA_InitTypeDef         DMA_InitStructure;
       
        RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
       
        DMA_Cmd(DMA1_Channel7, DISABLE);  
        DMA_DeInit(DMA1_Channel7);
        DMA_InitStructure.DMA_BufferSize=sizeof(gprsTxBuf);                                //ÏÈÉèÖÃΪ1K´óС
        DMA_InitStructure.DMA_DIR=DMA_DIR_PeripheralDST;
        DMA_InitStructure.DMA_M2M=DMA_M2M_Disable;               
        DMA_InitStructure.DMA_MemoryBaseAddr=(uint32_t)gprsTxBuf;
        DMA_InitStructure.DMA_MemoryDataSize=DMA_MemoryDataSize_Byte;
        DMA_InitStructure.DMA_MemoryInc=DMA_MemoryInc_Enable;
        DMA_InitStructure.DMA_Mode=DMA_Mode_Normal;
        DMA_InitStructure.DMA_PeripheralBaseAddr=(u32)&USART2->DR;
        DMA_InitStructure.DMA_PeripheralDataSize=DMA_PeripheralDataSize_Byte;
        DMA_InitStructure.DMA_PeripheralInc=DMA_PeripheralInc_Disable;
        DMA_InitStructure.DMA_Priority=DMA_Priority_High;
        DMA_Init(DMA1_Channel7,&DMA_InitStructure);                //³õʼ»¯TXµÄDMA
}
//发送DMA初始化
void rx_dma_init(void)
{
        DMA_InitTypeDef DMA_InitStructure;


        RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
        DMA_InitStructure.DMA_PeripheralBaseAddr = USART_DR_ADDRESS;
        DMA_InitStructure.DMA_MemoryBaseAddr = (u32)gprsRxBuf;
        DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
        DMA_InitStructure.DMA_BufferSize = sizeof(gprsRxBuf);
        DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
        DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
        DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
        DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;         
        DMA_InitStructure.DMA_Mode = DMA_Mode_Normal ;
        DMA_InitStructure.DMA_Priority = DMA_Priority_High;
        DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;          
        DMA_Init(DMA1_Channel6, &DMA_InitStructure);
        DMA_Cmd (DMA1_Channel6,ENABLE);
}




//串口初始化
void uart_init(void)
{
        GPIO_InitTypeDef   GPIO_InitStructure;   
        USART_InitTypeDef  USART_InitStructure;         
        NVIC_InitTypeDef   NVIC_InitStructure;       
       
        RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA        , ENABLE);
        RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
       
        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
        GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
        GPIO_Init(GPIOA, &GPIO_InitStructure);
       
        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
        GPIO_Init(GPIOA, &GPIO_InitStructure);
       
        NVIC_InitStructure.NVIC_IRQChannel=USART2_IRQn;
        NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3;
        NVIC_InitStructure.NVIC_IRQChannelSubPriority=0;
        NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
        NVIC_Init(&NVIC_InitStructure);
       
        USART_InitStructure.USART_BaudRate = 115200;
        USART_InitStructure.USART_WordLength = USART_WordLength_8b;       
        USART_InitStructure.USART_StopBits = USART_StopBits_1;
        USART_InitStructure.USART_Parity = USART_Parity_No;
        USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
        USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
        USART_Init(USART2, &USART_InitStructure);
       
        USART_DMACmd(USART2,USART_DMAReq_Tx,ENABLE);
        USART_DMACmd(USART2,USART_DMAReq_Rx,ENABLE);
       
        USART_ClearFlag(USART2,USART_FLAG_RXNE);
        USART_ClearFlag(USART2, USART_FLAG_TC);
        USART_ITConfig(USART2,USART_IT_IDLE,ENABLE);
       
        USART_Cmd(USART2, ENABLE);
}
//DMA发送数据
void send_commend(u8 *buf,u16 size)
{
        memset(gprsTxBuf,0,100);
        memcpy(gprsTxBuf,buf,size);
       
        DMA_Cmd(DMA1_Channel7,DISABLE);
        DMA_SetCurrDataCounter(DMA1_Channel7,size);
        DMA_Cmd(DMA1_Channel7,ENABLE);
}


void gprs_dma_reset()
{
    DMA_Cmd(DMA1_Channel6, DISABLE );
    DMA_SetCurrDataCounter(DMA1_Channel6, sizeof(gprsRxBuf));
    DMA_Cmd(DMA1_Channel6, ENABLE);  
}


extern u8 gprsRecOverFlag;
extern u16 gprsRecCnt;
void USART2_IRQHandler(void)            
{


        u16 uartRecCnt=0;


        if(USART_GetITStatus(USART2, USART_IT_IDLE) != RESET)
        {
                USART_ReceiveData(USART2);
                uartRecCnt = sizeof(gprsRxBuf) - DMA_GetCurrDataCounter(DMA1_Channel6);
                //**********************//
                gprsRecOverFlag=1;
                gprsRecCnt=uartRecCnt;
                //*************************************//
                gprs_dma_reset();              
                USART_ClearITPendingBit(USART2,USART_IT_IDLE);   
        }
}