mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-26 11:47:31 +00:00
31acd246c0
This is performed by using a line similar to: controller scbus0 at ahc0 bus 1 to wire scbus0 to the second bus on an adaptec 2742T controller. Reviewed by: Peter Dufault(dufault@hda.com), Rod Grimes(rgrimes@FreeBSD.org)
160 lines
5.7 KiB
Groff
160 lines
5.7 KiB
Groff
.Dd August 27, 1993
|
|
.Dt SD 4
|
|
.Os FreeBSD
|
|
.Sh NAME
|
|
.Nm scsi
|
|
.Nd scsi system
|
|
.Sh SYNOPSIS
|
|
.Nm controller scbus0
|
|
.Nm controller scbus1 at ahc0
|
|
.Nm controller scbus3 at ahc1 bus 0
|
|
.Nm controller scbus2 at ahc1 bus 1
|
|
.Nm device cd0
|
|
.Nm device ch0
|
|
.Nm disk sd0
|
|
.Nm tape st0
|
|
.Nm device ch1 at scbus0 target 4 unit 0
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Em scsi
|
|
system provides a uniform and modular system for the implementation
|
|
of drivers to control various scsi devices, and to utilise different
|
|
scsi host adapters through host adapter drivers. When the system probes the
|
|
.Em SCSI
|
|
busses, it attaches any devices it finds to the appropriate
|
|
drivers. If no driver seems appropriate, then it attaches the device to the
|
|
uk (unknown) driver so that user level scsi ioctls may
|
|
still be performed against the device.
|
|
.Sh KERNEL CONFIGURATION
|
|
The option SCSIDEBUG enables the debug ioctl.
|
|
.Pp
|
|
All devices and the SCSI busses support boot time allocation so that
|
|
an upper number of devices and controllers does not need to be configured;
|
|
.Em "device sd0"
|
|
will suffice for any number of disk drivers.
|
|
.Pp
|
|
The devices are either
|
|
.Em wired
|
|
so they appear as a particular device unit or
|
|
.Em counted
|
|
so that they appear as the next available unused unit.
|
|
.Pp
|
|
To configure a driver in the kernel without wiring down the device use a
|
|
config line similar to
|
|
.Em "device ch0"
|
|
to include the changer driver.
|
|
.Pp
|
|
To wire down a unit use a config line similar to
|
|
.Em "device ch1 at scbus0 target 4 unit 0"
|
|
to assign changer 1 as the changer with SCSI ID 4,
|
|
SCSI logical unit 0 on SCSI bus 0.
|
|
Individual scbuses can be wired down to specific controllers with
|
|
a config line similar to
|
|
.Em "controller scbus0 at ahc0"
|
|
which assigns scsi bus 0 to the first unit using the ahc driver.
|
|
For controllers supporting more than one bus,
|
|
the particualar bus can be specified as in
|
|
.Em "controller scbus3 at ahc1 bus 1"
|
|
which assigns scbus 1 to the second bus probled on the ahc1 device.
|
|
.Pp
|
|
When you have a mixture of wired down and counted devices then the
|
|
counting begins with the first non-wired down unit for a particular
|
|
type. That is, if you have a disk wired down as
|
|
.Em "disk sd1" ,
|
|
then the first non-wired disk shall come on line as
|
|
.Em sd2 .
|
|
.Sh IOCTLS
|
|
There are a number of ioctls that work on any
|
|
.Em SCSI
|
|
device. They are defined in
|
|
.Em sys/scsiio.h
|
|
and can be applied against any scsi device that permits them.
|
|
For the tape, it must be applied against the control
|
|
device. See the manual page for each device type for more information about
|
|
how generic scsi ioctls may be applied to a specific device.
|
|
.Bl -tag -width DIOCSDINFO____
|
|
.It Dv SCIOCRESET*
|
|
reset a device.
|
|
.It Dv SCIOCDEBUG
|
|
Turn on debugging.. All scsi operations originating from this device's driver
|
|
will be traced to the console, along with other information. Debugging is
|
|
controlled by four bits, described in the header file. If no debugging is
|
|
configured into the kernel, debugging will have no effect.
|
|
.Em SCSI
|
|
debugging is controlled by the configuration option
|
|
.Em SCSIDEBUG.
|
|
.It Dv SCIOCCOMMAND
|
|
Take a scsi command and data from a user process and apply them to the scsi
|
|
device. Return all status information and return data to the process. The
|
|
ioctl will return a successful status even if the device rejected the
|
|
command. As all status is returned to the user, it is up to the user
|
|
process to examine this information to decide the success of the command.
|
|
.It Dv SCIOCREPROBE
|
|
Ask the system to probe the scsi busses for any new devices. If it finds
|
|
any, they will be attached to the appropriate drivers. The search can be
|
|
narrowed to a specific bus, target or lun. The new device may or may not
|
|
be related to the device on which the ioctl was performed.
|
|
.It Dv SCIOCIDENTIFY
|
|
Ask the driver what it's bus, target and lun are.
|
|
.It Dv SCIOCDECONFIG
|
|
Ask the device to dissappear. This may not happen if the device is in use.
|
|
.El
|
|
.Sh NOTES
|
|
the generic scsi part of the system is still being mapped out.
|
|
Watch this space for changes.
|
|
.Pp
|
|
A device by the name of su (scsi_user)
|
|
(e.g su0-0-0) will map bus, target and lun to minor numbers. I have not
|
|
yet decided yet whether this device will be able to open a device that is
|
|
already controlled by an explicit driver.
|
|
.Sh ADAPTERS
|
|
The system allows common device drivers to work through many different
|
|
types of adapters. The adapters take requests from the upper layers and do
|
|
all IO between the
|
|
.Em SCSI
|
|
bus and the system. The maximum size of a transfer is governed by the
|
|
adapter. Most adapters can transfer 64KB in a single operation, however
|
|
many can transfer larger amounts.
|
|
.Sh TARGET MODE
|
|
Some adapters support
|
|
.Em Target mode
|
|
in which the system is capable of operating as a device, responding to
|
|
operations initioated by another system. Target mode will be supported for
|
|
some adapters, but is not yet complete for this version of the scsi system.
|
|
.Sh FILES
|
|
see other scsi device entries.
|
|
.Sh DIAGNOSTICS
|
|
When the kernel is compiled with option SCSIDEBUG, the SCIOCDEBUG ioctl
|
|
can be used to enable various amounts of tracing information on any
|
|
specific device. Devices not being traced will not produce trace information.
|
|
The four bits that make up the debug level, each control certain types
|
|
of debugging information.
|
|
.Bl -tag -width THIS_WIDE_PLEASE
|
|
.It Dv Bit 0
|
|
Bit 0 shows all scsi bus operations including scsi commands,
|
|
error information and the first 48 bytes of any data transferred.
|
|
.It Dv Bit 1
|
|
Bit 1 shows routines called.
|
|
.It Dv Bit 2
|
|
Bit 2 shows information about what branches are taken and often some
|
|
of the return values of functions.
|
|
.It Dv Bit 3
|
|
Bit 3 shows more detailed information including DMA scatter-gather logs.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr ch 4
|
|
.Xr cd 4
|
|
.Xr sd 4
|
|
.Xr st 4
|
|
.Xr uk 4
|
|
.Xr su 4
|
|
.Xr aha 4
|
|
.Xr ahb 4
|
|
.Xr bt 4
|
|
.Xr uha 4
|
|
.Sh HISTORY
|
|
This
|
|
.Nm
|
|
system appeared in MACH 2.5 at TRW.
|
|
|