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:

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 NetBSD2.0.

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.