•dma_sync_single_for_device是Linux内核中用于同步设备与内存之间单个数据缓冲区的函数。 2. •dma_sync_single_for_device函数用于确保设备与内存中的数据一致性,即设备能够正确读取或写入内存中的数据。 •它会刷新设备或CPU缓存中的数据,使得设备操作的是内存中最新的数据。 •dma_sync_single_for_device...
这是伪代码,显示了您需要使用 dma_sync*() 接口的情况 my_card_setup_receive_buffer(structmy_card*cp,char*buffer,intlen){dma_addr_tmapping;mapping=dma_map_single(cp->dev,buffer,len,DMA_FROM_DEVICE);if(dma_mapping_error(cp->dev,mapping)){/** reduce current DMA mapping usage,* delay ...
voiddma_sync_single_for_cpu(structdevice *dev,dma_addr_tdma_handle,size_tsize,enumdma_data_direction direction) voiddma_sync_single_for_device(structdevice *dev,dma_addr_tdma_handle,size_tsize,enumdma_data_direction direction) voiddma_sync_sg_for_cpu(structdevice *dev,structscatterlist *sg,i...
.sync_single_for_cpu = __swiotlb_sync_single_for_cpu, .sync_single_for_device = __swiotlb_sync_single_for_device, .sync_sg_for_cpu = __swiotlb_sync_sg_for_cpu, .sync_sg_for_device = __swiotlb_sync_sg_for_device, .dma_supported = __swiotlb_dma_supported, .mapping_error = __s...
16 void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr, 17 size_t size, 18 enum dma_data_direction dir, 19 unsigned long attrs) page映射 1 dma_addr_t dma_map_page(struct device *dev, struct page *page, 2 size_t offset, size_t size, ...
count= dma->tx_bytes_requested -state.residue;/*调用如下接口,使cpu看到内存的最新数据,因为该内存原先由DMA操作*/dma_sync_single_for_cpu(ourport->port.dev, dma->tx_transfer_addr, dma->tx_size, DMA_TO_DEVICE);/*从tty层请求更多数据*/spin_lock_irqsave(&port->lock, flags); ...
(2)在向外传输(tx)时,一种可能的情形是CPU构造的本地协议栈反馈包还在D-Cache中,故在send调用中需要先Flush D-Cache(sync_single_for_device)将数据写回(write back)到内存,使DMA缓存更新为最新鲜的待发送数据再启动DMA TX trigger。 需要注意的是,在某些平台上,比如ARM,CPU的读/写用的是不同的cache(读...
the driver can give a virtual address X to an interface like dma_map_single(), which sets up any required IOMMU mapping and returns the DMA address Z. The driver then tells the device to do DMA to Z, and the IOMMU maps it to the buffer at address Y in system RAM. 在某些简单的系...
.sync_single_for_cpu = iommu_dma_sync_single_for_cpu, .sync_single_for_device = iommu_dma_sync_single_for_device, .sync_sg_for_cpu = iommu_dma_sync_sg_for_cpu, .sync_sg_for_device = iommu_dma_sync_sg_for_device, .map_resource = iommu_dma_map_resource, ...
.sync_single_for_cpu= mips_dma_sync_single_for_cpu, .sync_single_for_device= mips_dma_sync_single_for_device, .sync_sg_for_cpu= mips_dma_sync_sg_for_cpu, .sync_sg_for_device= mips_dma_sync_sg_for_device, .mapping_error= mips_dma_mapping_error, ...