From patchwork Tue Jan 25 01:11:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Iwona Winiarska X-Patchwork-Id: 536629 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 955D2C433F5 for ; Tue, 25 Jan 2022 03:35:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S3420503AbiAYDfh (ORCPT ); Mon, 24 Jan 2022 22:35:37 -0500 Received: from mga09.intel.com ([134.134.136.24]:16189 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S3415309AbiAYBkN (ORCPT ); Mon, 24 Jan 2022 20:40:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643074813; x=1674610813; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=o9Was9ki72grzMbUkZV5f169uo+CSki1buMNORj9WMM=; b=Iosa+Kgzx0kFeJdFxfW8uK+QuingCN9G16mSMlvGKUnkajpDY+ZElQpS GTLjyzf4S5hvYD4cSO61srK1b0FrNqu3BDAaUDMupzWlpuYoMHVEXbOia nnlsgbCruCX2nJUzB7bm7Qasxv1DGZWmIX9YBlfbHfSon/K09AJzSwejS ysFkjlUFDioS/zkmbfzDws7egrHObwjgmSNosgBTtLcC1VM2R+EySeihZ 86xsrGEVqNOrhtws6CHxSPOKdN8dxKe+/jdfYl62Yy3KoGD8KtcJaSctp JMpgRlzhx81IeUnGsYgkzUqgJy2zVSqHG0jwV7+hHPzpUhQEeTAP4sdpH A==; X-IronPort-AV: E=McAfee;i="6200,9189,10237"; a="245971866" X-IronPort-AV: E=Sophos;i="5.88,313,1635231600"; d="scan'208";a="245971866" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jan 2022 17:17:58 -0800 X-IronPort-AV: E=Sophos;i="5.88,313,1635231600"; d="scan'208";a="695635197" Received: from kerguder-mobl.ger.corp.intel.com (HELO localhost) ([10.249.158.133]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jan 2022 17:17:44 -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 v6 13/13] docs: Add PECI documentation Date: Tue, 25 Jan 2022 02:11:04 +0100 Message-Id: <20220125011104.2480133-14-iwona.winiarska@intel.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220125011104.2480133-1-iwona.winiarska@intel.com> References: <20220125011104.2480133-1-iwona.winiarska@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@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 2b4de3926858..deaa7f669fcd 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 d821aeaaa2d3..06449cc42a10 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15112,6 +15112,7 @@ 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