Handling dma operations in framework-based drivers

 · A set of framework DMA objects and methods that drivers use to convert I/O requests into DMA operations. A set of driver-supplied event callback functions that configure the device's DMA behavior as different events occur. The framework supports both single packet and scatter/gather DMA transfers. It also supports the use of common buffers. On SoC-based . The driver uses DMA engine routines (see ddi_dmae(9F)) to initialize and program the DMA engine. For each DMA data transfer, the driver programs the DMA engine and then gives the device a command to initiate the transferin cooperation with that engine. First-party DMA.  · To handle bus-master and system-mode DMA operations in a framework-based driver, the framework provides three objects: DMA enabler object The framework's DMA enabler object enables a driver to use the framework's DMA support for a particular device. The driver must create a DMA enabler object for each of its devices that supports DMA .

The driver completes its DMA-specific initialization by calling WdfCommonBufferGetAlignedLogicalAddress to get the device bus logical address of the common buffer. Finally, the driver creates a DMA transaction object by calling WdfDmaTransactionCreate, passing a handle to the DMA enabler object. The driver uses this transaction object for all DMA read requests. KMDF drivers can use the framework's DMA enabler objects and DMA transaction objects to handle a device's direct memory access (DMA) operations. If your KMDF driver's device supports DMA operations, the driver should call WdfDmaEnablerCreate to create a DMA enabler object and WdfDmaTransactionCreate to create one or more DMA transaction objects. The DMA routines then perform any platform-specific operations needed to set the object up for DMA access. The driver receives a DMA handle to identify the DMA resources allocated for the object. This handle is opaque to the device driver; the driver must save the handle and pass it in subsequent calls to DMA routines, but should not interpret it in any way.

١٠‏/٠٨‏/٢٠٢٠ The WDF Framework is its own I/O processing ecosystem. and Close, in which the operation takes place based on a specific File Object. ١٦‏/١١‏/٢٠١١ As I've pointed out in previous articles, if your device doesn't handle interrupts, perform direct memory access (DMA), or require other kernel. This DMA device supports two modes of operation: contiguous transfer and In scatter-gather mode the bytes are instead copied from a data structure known.