IOPAAU(4)

NAME
iopaau - Intel I/O Processor Application Accelerator Unit

SYNOPSIS
iopxs* at mainbus?
iopaau* at iopxs?

DESCRIPTION
The Application Accelerator Unit, or AAU, provides hardware-assisted support for performing block fills on a region of memory, XOR of multiple regions of memory (parity computation), and parity verification.

The iopaau driver supports the Application Accelerator Units on the following Intel I/O Processors:

•   Intel i80321 I/O Processor

The iopaau driver provides a back-end to the dmover(9) interface, and supports the following dmover(9) functions:

zero
    Zero a region of memory

fill8
    Fill a region of memory with an 8-bit value

copy
    Copy a region of memory

xor2
    Perform an XOR of 2 input streams

xor3
    Perform an XOR of 3 input streams

xor4
    Perform an XOR of 4 input streams

xor5
    Perform an XOR of 5 input streams

xor6
    Perform an XOR of 6 input streams

xor7
    Perform an XOR of 7 input streams

xor8
    Perform an XOR of 8 input streams

SEE ALSO
dmover(9)

HISTORY
The iopaau device first appeared in NetBSD 2.0.

AUTHORS
The iopaau driver was written by Jason R. Thorpe <thorpej@wasabisystems.com> and contributed by Wasabi Systems, Inc.

BUGS
Due to limitations in how scatter-gather is done by the AAU hardware, a given DMA segment must be the same length for the output stream and each input stream. The easiest way to achieve this is to ensure that all streams used in an AAU operation begin at the same offset into a page.