From patchwork Wed Jan 12 23:02:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Winiarska, Iwona" X-Patchwork-Id: 12712046 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C5D7C433EF for ; Wed, 12 Jan 2022 23:09:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235315AbiALXJs (ORCPT ); Wed, 12 Jan 2022 18:09:48 -0500 Received: from mga17.intel.com ([192.55.52.151]:5928 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235388AbiALXJP (ORCPT ); Wed, 12 Jan 2022 18:09:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1642028955; x=1673564955; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=zSmYRU8FIGX3cJZGcSG6CFzwqnaKQim/SWuh0EbKmk4=; b=IJSXFFTzi7GwHQX8CKbBpIe3b7sKSQfP73SDJe9K0Bgk4MWfwCQs0RWV Ww0aPTopw4B0FbTvIMiqMDw0FRW0XGAlyTokR/Gu7siaU/M8LL8hkj59m L3ESPIw8lcvcMLwDWS/iQzwf0HSWk6LkJvStulhbL2Rp38WfdLBB1TBta eGW7K1OAGZ4aiFjFTc6K6gZ0IpB/TL1boCDUEQY1drniY64dP+IEtfNy8 TBT5WpHNd9dPBwauMPQ5QWp7DYF+10QaUoRVWxKfiIB9iuHQ8wwSLmMjX SC9+FT1GG5Fuh6Gmy+9GS59jL7hZl3HZSUD2KvOAXQA6DbSDfqw4Cg79e A==; X-IronPort-AV: E=McAfee;i="6200,9189,10225"; a="224564667" X-IronPort-AV: E=Sophos;i="5.88,284,1635231600"; d="scan'208";a="224564667" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 15:09:13 -0800 X-IronPort-AV: E=Sophos;i="5.88,284,1635231600"; d="scan'208";a="576736956" Received: from kstefans-mobl.ger.corp.intel.com (HELO localhost) ([10.249.154.174]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 15:09:05 -0800 From: Iwona Winiarska To: linux-kernel@vger.kernel.org, openbmc@lists.ozlabs.org, Greg Kroah-Hartman Cc: devicetree@vger.kernel.org, linux-aspeed@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-hwmon@vger.kernel.org, linux-doc@vger.kernel.org, Rob Herring , Joel Stanley , Andrew Jeffery , Jean Delvare , Guenter Roeck , Arnd Bergmann , Olof Johansson , Jonathan Corbet , Borislav Petkov , Pierre-Louis Bossart , Tony Luck , Andy Shevchenko , Dan Williams , Randy Dunlap , Zev Weiss , David Muller , Dave Hansen , Billy Tsai , Iwona Winiarska Subject: [PATCH v5 13/13] docs: Add PECI documentation Date: Thu, 13 Jan 2022 00:02:47 +0100 Message-Id: <20220112230247.982212-14-iwona.winiarska@intel.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220112230247.982212-1-iwona.winiarska@intel.com> References: <20220112230247.982212-1-iwona.winiarska@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org Add a brief overview of PECI and PECI wire interface. The documentation also contains kernel-doc for PECI subsystem internals and PECI CPU Driver API. Signed-off-by: Iwona Winiarska Reviewed-by: Pierre-Louis Bossart --- Documentation/index.rst | 1 + Documentation/peci/index.rst | 16 +++++++++++ Documentation/peci/peci.rst | 51 ++++++++++++++++++++++++++++++++++++ MAINTAINERS | 1 + 4 files changed, 69 insertions(+) create mode 100644 Documentation/peci/index.rst create mode 100644 Documentation/peci/peci.rst diff --git a/Documentation/index.rst b/Documentation/index.rst index 54ce34fd6fbd..7671f2cd474f 100644 --- a/Documentation/index.rst +++ b/Documentation/index.rst @@ -137,6 +137,7 @@ needed). misc-devices/index scheduler/index mhi/index + peci/index Architecture-agnostic documentation ----------------------------------- diff --git a/Documentation/peci/index.rst b/Documentation/peci/index.rst new file mode 100644 index 000000000000..989de10416e7 --- /dev/null +++ b/Documentation/peci/index.rst @@ -0,0 +1,16 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +==================== +Linux PECI Subsystem +==================== + +.. toctree:: + + peci + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/peci/peci.rst b/Documentation/peci/peci.rst new file mode 100644 index 000000000000..331b1ec00e22 --- /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 diff --git a/MAINTAINERS b/MAINTAINERS index 6ae398baffc8..908ebdf5ffff 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -14943,6 +14943,7 @@ M: Iwona Winiarska L: openbmc@lists.ozlabs.org (moderated for non-subscribers) S: Supported F: Documentation/devicetree/bindings/peci/ +F: Documentation/peci/ F: drivers/peci/ F: include/linux/peci-cpu.h F: include/linux/peci.h