0001 .. SPDX-License-Identifier: GPL-2.0-only
0002
0003 ========
0004 Overview
0005 ========
0006
0007 The Platform Environment Control Interface (PECI) is a communication
0008 interface between Intel processor and management controllers
0009 (e.g. Baseboard Management Controller, BMC).
0010 PECI provides services that allow the management controller to
0011 configure, monitor and debug platform by accessing various registers.
0012 It defines a dedicated command protocol, where the management
0013 controller is acting as a PECI originator and the processor - as
0014 a PECI responder.
0015 PECI can be used in both single processor and multiple-processor based
0016 systems.
0017
0018 NOTE:
0019 Intel PECI specification is not released as a dedicated document,
0020 instead it is a part of External Design Specification (EDS) for given
0021 Intel CPU. External Design Specifications are usually not publicly
0022 available.
0023
0024 PECI Wire
0025 ---------
0026
0027 PECI Wire interface uses a single wire for self-clocking and data
0028 transfer. It does not require any additional control lines - the
0029 physical layer is a self-clocked one-wire bus signal that begins each
0030 bit with a driven, rising edge from an idle near zero volts. The
0031 duration of the signal driven high allows to determine whether the bit
0032 value is logic '0' or logic '1'. PECI Wire also includes variable data
0033 rate established with every message.
0034
0035 For PECI Wire, each processor package will utilize unique, fixed
0036 addresses within a defined range and that address should
0037 have a fixed relationship with the processor socket ID - if one of the
0038 processors is removed, it does not affect addresses of remaining
0039 processors.
0040
0041 PECI subsystem internals
0042 ------------------------
0043
0044 .. kernel-doc:: include/linux/peci.h
0045 .. kernel-doc:: drivers/peci/internal.h
0046 .. kernel-doc:: drivers/peci/core.c
0047 .. kernel-doc:: drivers/peci/request.c
0048
0049 PECI CPU Driver API
0050 -------------------
0051 .. kernel-doc:: drivers/peci/cpu.c
