From a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Wed, 5 Aug 2026 07:52:36 -0700 Subject: workqueue: skip the node_nr_active update for non-unbound workqueues apply_wqattrs_commit() updates node_nr_active->max unconditionally. wq->node_nr_active[] is only allocated for unbound workqueues, so guard the call before per-cpu workqueues start using this path. No functional change: only unbound workqueues reach apply_wqattrs_*() today. Signed-off-by: Breno Leitao Signed-off-by: Tejun Heo --- Documentation/peci/index.rst | 9 ++++++++ Documentation/peci/peci.rst | 51 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 60 insertions(+) create mode 100644 Documentation/peci/index.rst create mode 100644 Documentation/peci/peci.rst (limited to 'Documentation/peci') diff --git a/Documentation/peci/index.rst b/Documentation/peci/index.rst new file mode 100644 index 000000000..1443c31a0 --- /dev/null +++ b/Documentation/peci/index.rst @@ -0,0 +1,9 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============== +PECI Subsystem +============== + +.. toctree:: + + peci diff --git a/Documentation/peci/peci.rst b/Documentation/peci/peci.rst new file mode 100644 index 000000000..331b1ec00 --- /dev/null +++ b/Documentation/peci/peci.rst @@ -0,0 +1,51 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +======== +Overview +======== + +The Platform Environment Control Interface (PECI) is a communication +interface between Intel processor and management controllers +(e.g. Baseboard Management Controller, BMC). +PECI provides services that allow the management controller to +configure, monitor and debug platform by accessing various registers. +It defines a dedicated command protocol, where the management +controller is acting as a PECI originator and the processor - as +a PECI responder. +PECI can be used in both single processor and multiple-processor based +systems. + +NOTE: +Intel PECI specification is not released as a dedicated document, +instead it is a part of External Design Specification (EDS) for given +Intel CPU. External Design Specifications are usually not publicly +available. + +PECI Wire +--------- + +PECI Wire interface uses a single wire for self-clocking and data +transfer. It does not require any additional control lines - the +physical layer is a self-clocked one-wire bus signal that begins each +bit with a driven, rising edge from an idle near zero volts. The +duration of the signal driven high allows to determine whether the bit +value is logic '0' or logic '1'. PECI Wire also includes variable data +rate established with every message. + +For PECI Wire, each processor package will utilize unique, fixed +addresses within a defined range and that address should +have a fixed relationship with the processor socket ID - if one of the +processors is removed, it does not affect addresses of remaining +processors. + +PECI subsystem internals +------------------------ + +.. kernel-doc:: include/linux/peci.h +.. kernel-doc:: drivers/peci/internal.h +.. kernel-doc:: drivers/peci/core.c +.. kernel-doc:: drivers/peci/request.c + +PECI CPU Driver API +------------------- +.. kernel-doc:: drivers/peci/cpu.c -- cgit v1.3.1