Context -> AdapterObject, MAX_MAPPING,sizeof(KSMAPPING) ); } ... 此代码示例适用于 64 位和 32 位平台。 如果驱动程序找不到IKsDeviceFunctions::RegisterAdapterObjectEx,它仍调用KsDeviceRegisterAdapter。 此外,在创作 64 位 AVStream 驱动程序时,请尽量减少持有的并发帧锁数。 由于 AVStream 在微型...
size_t dma_max_mapping_size(struct device *dev); Returns the maximum size of a mapping for the device. The size parameter of the mapping functions like dma_map_single(), dma_map_page() and others should not be larger than the returned value. 返回设备映射的最大大小。dma_map_single()、...
.max_mapping_size = swiotlb_max_mapping_size, };2 changes: 1 addition & 1 deletion 2 include/linux/dma-map-ops.h Original file line numberDiff line numberDiff line change @@ -29,7 +29,7 @@ struct dma_map_ops { unsigned long attrs); void (*free)(struct device *dev, size_t ...
else if (devinfo->flags & US_FL_MAX_SECTORS_240) blk_queue_max_hw_sectors(sdev->request_queue, 240);blk_queue_max_hw_sectors(sdev->request_queue, min_t(size_t, queue_max_hw_sectors(sdev->request_queue), dma_max_mapping_size(dev) >> SECTOR_SHIFT));if...
DMA MAPPING 需要Buffer 需要Buffer描述符 启动传输 交给DMAC dmaengine_submitBuffer 控制DMA 寄存器位开启 等待传输完成 等待DMA 中断 读DMA 寄存器状态位 中断处理 硬件中断基础上,使用 DMAC 收发数据都将多产生一次中断 都有 数据BUFFER 自己处理 自己处理 描述符 需要申请 自己管理 最重要的概念是:谁是 DMA 传输...
memset(max_zone_pfns, 0, sizeof(max_zone_pfns)); max_zone_pfns[ZONE_DMA] = virt_to_pfn(MAX_DMA_ADDRESS); max_zone_pfns[ZONE_NORMAL] = max_low_pfn; diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
void(*unmap)(struct vm_area_struct *vma,unsigned long addr,size_t len); 核心调用这个方法取消一个区域的部分或全部映射。如果整个区域的映射被取消,核心在vm_ops->unmap返回后立即调用vm_ops->close。 void (*protect)(struct vm_area_struct *vma,unsigned long,size_t,unsigned int new prot); ...
include/linux/dma-mapping.h:点击(此处)折叠或打开 struct dma_map_ops { void* (*alloc)(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, struct dma_attrs *attrs); void (*free)(struct device *dev, size_t size, ...
This field gives the granularity in bytes of the DMA transfer ability of the device. An example of how this value is used is to specify the sector size of a mass storage device. When a bind operation requires a partial mapping, this field is used to ensure that the sum of the sizes ...
*/map->dm_mapsize =0;map->dm_nsegs =0; KASSERT(map->dm_maxsegsz <=map->_dm_maxmaxsegsz);if(buflen >map->_dm_size)return(EINVAL);if(p !=NULL) { vm = p->p_vmspace; }else{ vm = vmspace_kernel(); } seg =0;