/** * dma_buf_get - returns the dma_buf structure related to an fd * @fd: [in] fd associated with the dma_buf to be returned * * On success, returns the dma_buf structure associated with an fd; uses * file's refcounting done by fget to increase refcount. returns ERR_PTR * ot...
ddi_dma_addr_bind_handle(9F), ddi_dma_alloc_handle(9F), ddi_dma_free_handle(9F), ddi_dma_getwin(9F), ddi_dma_nextcookie(9F), ddi_dma_sync(9F), ddi_dma_unbind_handle(9F), buf(9S), ddi_dma_attr(9S), ddi_dma_cookie(9S) Writing Device Drivers ...
A DMA buffer allocated by u-dma-buf can be accessed from the user space by opening the device file (e.g. /dev/udmabuf0) and mapping to the user memory space, or using the read()/write() functions.CPU cache for the allocated DMA buffer can be disabled by setting the O_SYNC flag ...
adc_buf[6] =(int)(u16)ADC_ConvertedValue[6];//A4 adc_buf[7] =(int)(u16)ADC_ConvertedValue[7];//A4 adc_buf[8] =(int)(ADC_ConvertedValue[0]>>16);//A8 adc_buf[9] =(int)(ADC_ConvertedValue[1]>>16);//A8 adc_buf[10]=(int)(ADC_ConvertedValue[2]>>16);//A8 adc_buf[11]...
如果将 NULL 作为buf(9S) 结构指针传递,则指示 physio(9F) 分配buf(9S) 结构。如果驱动程序必须向 physio(9F) 提供buf(9S) 结构,应使用 getrbuf(9F) 来分配该结构。如果传输成功完成,physio(9F) 返回零;如果传输失败,则返回错误号。调用 strategy(9E) 后,physio(9F) 会调用 biowait(9F) 以进入阻塞状态...
(struct dma_chan *chan, dma_addr_t buf, size_t len, size_t period_len, enum dma_transfer_direction dir, unsigned long flags) { struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan); struct dma_slave_config *sconfig = &vchan->cfg; struct sun4i_dma_promise *promise; ...
HAL_DMA_Start_IT(&hdma_tx, *TBuf0,(uint32_t) &(SPI4->TXDR),TBS0); } function for SPI_DMA init #define VIDEO_DMA DMA2 #define DMA_STREAM DMA2_Stream3 #define DMA_CHANNEL DMA_Channel_3 void SPI_Configuration( void ) {
MYDMA_Enable(DMA2_Stream7,SEND_BUF_SIZE); //开始一次DMA传输! while(1) { if(DMA_GetFlagStatus(DMA2_Stream7,DMA_FLAG_TCIF7)!=RESET)//等待DMA2_Steam7传输完成 { DMA_ClearFlag(DMA2_Stream7,DMA_FLAG_TCIF7);//清除DMA2_Steam7传输完成标志 ...
Function Name: uint16_t ring_buf_len(ring_buff* ring_buff) Description: get the valid data length Input: Return: get the valid data length Others: ***/uint16_t Ring_Buf_Len(ring_buff*ring_buffer) {returnring_buffer->Rear_Index - ring_buffer->Front_Index;//get the valid data length...
严谨的做法需要做双buf,CPU和DMA各自一块内存交替访问,即是"乒乓缓存” ,处理流程步骤应该是这样: 【1】第一步,DMA先将数据搬运到buf1,搬运完成通知CPU来拷贝buf1数据 【2】第二步,DMA将数据搬运到buf2,与CPU拷贝buf1数据不会冲突 【3】第三步,buf2数据搬运完成,通知CPU来拷贝buf2数据 ...