From patchwork Tue Feb 8 15:36:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Winiarska, Iwona" X-Patchwork-Id: 12738921 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 3B579C433EF for ; Tue, 8 Feb 2022 15:42:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1381322AbiBHPmU (ORCPT ); Tue, 8 Feb 2022 10:42:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1381476AbiBHPmR (ORCPT ); Tue, 8 Feb 2022 10:42:17 -0500 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 46794C0612B9; Tue, 8 Feb 2022 07:42:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1644334933; x=1675870933; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=4GFjvUMiVMcumvdOgAlzmh492IdarzKncsOwfSSWUls=; b=d3ZHEdZ3XkH+gQrXw5FmwH3LcJoGIB/nc4KwuJoSDSiYaD/oXfHH6XJn uM8jv8A80rqFyYgxO/5LzqnAD8aHpwzAkNLASD6dqmR99hf1PYdKNqdpy hZ5WJjlRhk5n9bnIJFtoA/7U48QxjS7RBjdU5WLZ9h50aaMAUkj4BlWnp VX9QHuAWekNhld3LfkTQ869E2APSUmBLTGd6VuD1/Cq4kPlp+ySWnVvyp zmZG14lnYg4ryoBElIYHvVc9xH/HAlTcL1kdPBPF21scIeKUciJPBpLeU jIgohHIg9IsuErx4LHM4V0x3hVRYiPwRHJHVRtOLJqki/mX0AtUxZVk6i w==; X-IronPort-AV: E=McAfee;i="6200,9189,10252"; a="228940640" X-IronPort-AV: E=Sophos;i="5.88,353,1635231600"; d="scan'208";a="228940640" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2022 07:42:13 -0800 X-IronPort-AV: E=Sophos;i="5.88,353,1635231600"; d="scan'208";a="601273985" Received: from mgorzkow-mobl1.ger.corp.intel.com (HELO localhost) ([10.249.139.232]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2022 07:42:07 -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 v8 13/13] docs: Add PECI documentation Date: Tue, 8 Feb 2022 16:36:39 +0100 Message-Id: <20220208153639.255278-14-iwona.winiarska@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220208153639.255278-1-iwona.winiarska@intel.com> References: <20220208153639.255278-1-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 b58692d687f6..1988c19d9daf 100644 --- a/Documentation/index.rst +++ b/Documentation/index.rst @@ -138,6 +138,7 @@ needed). scheduler/index mhi/index tty/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 c666ef7ea5a5..9d248d55ac30 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15122,6 +15122,7 @@ 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