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.\" by Andrew Doran.
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.Dd December 2, 2007
.Dt IOP 4
.Os
.Sh NAME
.Nm iop
.Nd
.Tn I2O adapter driver
.Sh SYNOPSIS
.Cd "iop* at pci? dev ? function ?"
.Cd "iopsp* at iop? tid ?"
.Cd "ld* at iop? tid ?"
.Cd "dpti* at iop? tid 0"
.Sh DESCRIPTION
The
.Nm
driver provides support for
.Tn PCI
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, and Token Ring.
.It
Bus ports (SCSI).
.It
SCSI peripherals.
.El
.Pp
The
.Nm
driver's role is to initialize 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 .
Note that the headers
.Pa sys/types.h ,
.Pa sys/device.h
and
.Pa dev/i2o/i2o.h
are prerequisites and must therefore be included beforehand.
.Bl -tag -width OTTF
.It Dv IOPIOCPT (struct ioppt)
Submit a message to the IOP and return the reply.
Note that the return value of this ioctl is not affected by completion
status as indicated by the reply.
.Bd -literal
struct ioppt {
	void	*pt_msg;	/* pointer to message buffer */
	size_t	pt_msglen;	/* message buffer size in bytes */
	void	*pt_reply;	/* pointer to reply buffer */
	size_t	pt_replylen;	/* reply buffer size in bytes */
	int	pt_timo;	/* completion timeout in ms */
	int	pt_nbufs;	/* number of transfers */
	struct	ioppt_buf pt_bufs[IOP_MAX_MSG_XFERS]; /* transfers */
};

struct ioppt_buf {
	void	*ptb_data;	/* pointer to buffer */
	size_t	ptb_datalen;	/* buffer size in bytes */
	int	ptb_out;	/* non-zero if transfer is to IOP */
};
.Ed
.Pp
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, and can therefore not be safely
issued using the IOPIOCPT ioctl.
.El
.Pp
The following ioctls may block while attempting to acquire the
.Nm
driver's configuration lock, and may fail if the acquisition times out.
.Bl -tag -width OTTF
.It Dv IOPIOCGLCT (struct iovec)
Retrieve the
.Nm
driver's copy of the logical configuration table.
This copy of the LCT matches the current device configuration, but
is not necessarily the latest available version of the LCT.
.It Dv IOPIOCRECONFIG
Request that the
.Nm
driver scan all bus ports, retrieve the latest version of the LCT, and
attach or detach devices as necessary.
Note that higher-level reconfiguration tasks (such as logically
re-scanning SCSI busses) will not be performed by this ioctl.
.It Dv IOPIOCGTIDMAP (struct iovec)
Retrieve the TID to device map.
This map indicates which targets are
configured, and what the corresponding device name for each is.
Although at any given point it contains the same number of entries
as the LCT, the number of entries should be determined using the
iov_len field from the returned iovec.
.Bd -literal
struct iop_tidmap {
	u_short	it_tid;
	u_short	it_flags;
	char	it_dvname[sizeof(((struct device *)NULL)->dv_xname)];
};
#define	IT_CONFIGURED	0x02	/* target configured */
.Ed
.El
.Sh FILES
.Bl -tag -width /dev/iopn -compact
.It Pa /dev/iop Ns Ar u
control device for IOP unit
.Ar u
.El
.Sh SEE ALSO
.Xr dpti 4 ,
.Xr intro 4 ,
.Xr iopsp 4 ,
.Xr ld 4 ,
.Xr iopctl 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Nx 1.5.3 .