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Beef this up a little.

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ad 2001-08-04 17:06:22 +00:00
parent cc274c12b6
commit 6d6da41477
1 changed files with 48 additions and 1 deletions
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49
share/man/man4/iop.4
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@ -1,4 +1,4 @@
.\" $NetBSD: iop.4,v 1.8 2001/06/12 12:00:20 wiz Exp $
.\" $NetBSD: iop.4,v 1.9 2001/08/04 17:06:22 ad Exp $
.\"
.\" Copyright (c) 2000 The NetBSD Foundation, Inc.
.\" All rights reserved.
@ -54,6 +54,47 @@ driver provides support for
I/O processors conforming to the
.Tn I2O
specification, revision 1.5 and above.
.Pp
I2O is a specification that defines a software interface for communicating
with a number of device types. In its basic form, I2O provides the
following:
.Pp
.Bl -bullet
.It
A vendor-neutral interface for communicating with an I/O processor (IOP)
and a number of types of peripherals. In order to achieve this,
hardware-specific device drivers run on the IOP, and hardware-neutral device
drivers run on the host.
.It
Reduced I/O overhead for the host. All communication between the host and
the IOP is performed using a high level protocol. The specification also
provides for batching of requests and replies between the host and IOP.
.It
An optional vendor-neutral configuration interface. Data from HTTP GET and
POST operations can be channeled to individual devices, and HTML pages
returned.
.El
.Pp
Five types of devices are well defined by the specification. These are:
.Pp
.Bl -bullet -compact
.It
Random block storage devices (disks).
.It
Sequential storage devices (tapes).
.It
LAN interfaces, including Ethernet, FDDI, Token Ring and FC.
.It
Bus ports (SCSI).
.It
SCSI peripherals.
.El
.Pp
The
.Nm
driver's role is to initalize and monitor the IOP, provide a conduit for
messages and replies to and from devices, and provide other common services
for peripheral drivers, such as DMA mapping.
.Sh IOCTL INTERFACE
The following structures and constants are defined in
.Pa dev/i2o/iopio.h .
@ -90,6 +131,12 @@ The minimum timeout value that may be specified is 1000ms. All other values
must not exceed the
.Nm
driver's operational limits.
.Pp
The initiator context and transaction context fields in the message frame
will be filled by the
.Nm
driver. As such, this ioctl may not be used to send messages without a
transaction context payload.
.It Dv IOPIOCGSTATUS (struct iovec)
Request the latest available status record from the IOP. This special-case
ioctl is provided as the I2O_EXEC_STATUS_GET message does not post replies,