4d846d260e
The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch up to that fact and revert to their recommended match of BSD-2-Clause. Discussed with: pfg MFC After: 3 days Sponsored by: Netflix
133 lines
4.2 KiB
Groff
133 lines
4.2 KiB
Groff
.\"
|
|
.\" SPDX-License-Identifier: BSD-2-Clause
|
|
.\"
|
|
.\" Copyright (c) 2018 Panasas
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd March 2, 2018
|
|
.Dt IMCSMB 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm imcsmb
|
|
.Nd Intel integrated Memory Controller (iMC) SMBus controller driver
|
|
.Sh SYNOPSIS
|
|
.Cd device pci
|
|
.Cd device smbus
|
|
.Cd device imcsmb
|
|
.Pp
|
|
Alternatively, to load the driver as a module at boot time, place the following
|
|
line in
|
|
.Xr loader.conf 5 :
|
|
.Bd -literal -offset indent
|
|
imcsmb_load="YES"
|
|
.Ed
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
driver provides
|
|
.Xr smbus 4
|
|
support for the SMBus controller functionality in the integrated Memory
|
|
Controllers (iMCs) embedded in Intel Sandybridge-Xeon, Ivybridge-Xeon,
|
|
Haswell-Xeon, and Broadwell-Xeon CPUs.
|
|
Each CPU implements one or more iMCs, depending on the number of cores;
|
|
each iMC implements two SMBus controllers (iMC-SMBs).
|
|
The iMC-SMBs are used by the iMCs to read configuration information from the
|
|
DIMMs during POST.
|
|
They may also be used, by motherboard firmware or a BMC, to monitor the
|
|
temperature of the DIMMs.
|
|
.Pp
|
|
The iMC-SMBs are
|
|
.Sy not
|
|
general-purpose SMBus controllers.
|
|
By their nature, they are only ever attached to DIMMs, so they implement only
|
|
the SMBus operations need for communicating with DIMMs.
|
|
Specifically:
|
|
.Pp
|
|
.Bl -dash -offset indent -compact
|
|
.It
|
|
READB
|
|
.It
|
|
READW
|
|
.It
|
|
WRITEB
|
|
.It
|
|
WRITEW
|
|
.El
|
|
.Pp
|
|
A more detailed discussion of the hardware and driver architecture can be found
|
|
at the top of
|
|
.Pa sys/dev/imcsmb/imcsmb_pci.c .
|
|
.Sh WARNINGS
|
|
As mentioned above, firmware might use the iMC-SMBs to read DIMM temperatures.
|
|
The public iMC documentation does not describe any sort of coordination
|
|
mechanism to prevent requests from different sources -- such as the motherboard
|
|
firmware, a BMC, or the operating system -- from interfering with each other.
|
|
.Pp
|
|
.Bf Sy
|
|
Therefore, it is highly recommended that developers contact the motherboard
|
|
vendor for any board-specific instructions on how to disable and re-enable DIMM
|
|
temperature monitoring.
|
|
.Ef
|
|
.Pp
|
|
DIMM temperature monitoring should be disabled before returning from
|
|
.Fn imcsmb_pci_request_bus ,
|
|
and re-enabled before returning from
|
|
.Fn imcsmb_pci_release_bus .
|
|
The driver includes comments to that effect at the appropriate locations.
|
|
The driver has been tested and shown to work, with only that type of
|
|
modification, on certain motherboards from Intel.
|
|
.Po
|
|
Unfortunately, those modifications were based on material covered under a
|
|
non-disclosure agreement, and therefore are not included in this driver.
|
|
.Pc
|
|
The driver has also been tested and shown to work as-is on various motherboards
|
|
from SuperMicro.
|
|
.Pp
|
|
The
|
|
.Xr smb 4
|
|
driver will connect to the
|
|
.Xr smbus 4
|
|
instances created by
|
|
.Nm .
|
|
However, since the IMC-SMBs are not general-purpose SMBus controllers, using
|
|
.Xr smbmsg 8
|
|
with those
|
|
.Xr smb 4
|
|
devices is not supported.
|
|
.Sh SEE ALSO
|
|
.Xr jedec_dimm 4 ,
|
|
.Xr smbus 4
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
driver first appeared in
|
|
.Fx 12.0 .
|
|
.Sh AUTHORS
|
|
The
|
|
.Nm
|
|
driver was originally written for Panasas by
|
|
.An Joe Kloss .
|
|
It was substantially refactored, and this manual page was written, by
|
|
.An Ravi Pokala Aq Mt rpokala@freebsd.org
|