August 2, 2002 IOPAAU 4 evbarm

### 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 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.