Windows® 2000 Device Driver Book: A Guide for Programmers, Second Edition, The

Writing a Common Buffer Bus Master DMA Driver

In common-buffer bus master DMA, the device transfers data to or from a contiguous nonpaged pool buffer, using a DMA controller that is part of the device itself. Frequently, this kind of hardware treats the common buffer as a mailbox for exchanging control and status messages with the driver.

How Common-Buffer Bus Master DMA Works

The exact operation of a common-buffer bus master driver will depend on the physical device. The description that follows is based on the typical architecture. It assumes the device uses one mailbox for commands and another to return status information. Figure 12.7 illustrates this arrangement.

IRP_MN_START_DEVICE HANDLER

This handler must now perform the following tasks: ...