Working with Adapter Objects

Although the specific details vary with the nature of the device and the architecture of the driver, DMA drivers generally have to perform several kinds of operations on Adapter objects.

  • Locate the Adapter object associated with the specific device.

  • Acquire and release ownership of Adapter objects and their mapping registers.

  • Load the Adapter object's mapping registers at the start of a transfer.

  • Flush the Adapter object's cache after a transfer completes.

The following sections discuss these topics in general terms. Later sections of this chapter add more detail.

Finding the Right Adapter Object

All DMA drivers need to locate an Adapter object before they can perform any I/O operations. To find the right one, a driver's ...

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