From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6DB8C0044C for ; Wed, 7 Nov 2018 17:11:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7BFFE2081D for ; Wed, 7 Nov 2018 17:11:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="DO/l2bJS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7BFFE2081D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-pci-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731624AbeKHCmC (ORCPT ); Wed, 7 Nov 2018 21:42:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:38282 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731439AbeKHCmC (ORCPT ); Wed, 7 Nov 2018 21:42:02 -0500 Received: from localhost (unknown [64.22.249.253]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4BA1820883; Wed, 7 Nov 2018 17:10:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541610645; bh=LJAyj4HG6WxEKD4qnKwEopxUPQTdQJ+ExpoPS9iQuyw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DO/l2bJSuR+SlwR9MCcqELJTXvbnU8uyHOZAmx89zPOPM2EohbglKBmD1/uWKU5ms Ybx9hEENkIU3Nh+v67O0XDMKoXJovvHjwWrmgEEEwdr86HNwjknrNobjY+edOSm+LG WpntkiNLYHu63QI1YASSQVV/YX4rtMjVi9tn8OfE= Date: Wed, 7 Nov 2018 11:10:44 -0600 From: Bjorn Helgaas To: Borislav Petkov Cc: "Woods, Brian" , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "x86@kernel.org" , Clemens Ladisch , Jean Delvare , Guenter Roeck , Pu Wen , Jia Zhang , Takashi Iwai , Andy Whitcroft , Colin Ian King , Myron Stowe , Sumeet Pawnikar , Srinivas Pandruvada , "linux-kernel@vger.kernel.org" , "linux-hwmon@vger.kernel.org" , "linux-pci@vger.kernel.org" Subject: Re: [PATCH 2/4] x86/amd_nb: add support for newer PCI topologies Message-ID: <20181107171044.GA261200@google.com> References: <20181102195925.GB160487@google.com> <20181102232948.GC26770@zn.tnic> <20181105214537.GA19420@google.com> <20181105215650.GG26868@zn.tnic> <20181106214256.GA65443@google.com> <20181106220059.GA4139@zn.tnic> <20181106232040.GA85755@google.com> <20181107091838.GA10835@zn.tnic> <20181107133856.GA238955@google.com> <20181107160707.GA14169@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181107160707.GA14169@zn.tnic> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Nov 07, 2018 at 05:07:07PM +0100, Borislav Petkov wrote: > On Wed, Nov 07, 2018 at 07:38:56AM -0600, Bjorn Helgaas wrote: > > Firmware supplies ACPI namespace. The namespace contains an abstract > > description of the platform, including devices. Devices are > > identified by PNP IDs, which are analogous to PCI vendor/device IDs, > > except that a device may have several generic "compatible device IDs" > > in addition to an ID unique to the device. Devices may also contain > > methods (supplied by firmware as part of the namespace), which are > > essentially bytecode that can be executed by the ACPI interpreter in > > the kernel. Linux drivers claim ACPI devices based on PNP ID and > > operate them using either ACPI methods (which can decouple the driver > > from device specifics) or the usual direct MMIO/IO port/MSR style. > > > > Here's an outline of how it *could* work: > > > > - AMD defines "AMD0001" device ID for the CPU temp sensor > > - BIOS supplies AMD0001 devices in the ACPI namespace > > - Each AMD0001 device has a _TMP method (supplied by BIOS and > > specific to the CPU) > > - Linux driver claims AMD0001 devices > > - Driver reads temp sensors by executing _TMP methods (Linux ACPI > > interpreter runs the bytecode) > > Thanks for explaining. > > > That way when you release a new platform with different temp sensors, > > you update the BIOS AMD0001 devices and _TMP methods to know about > > them, and the old Linux driver works unchanged. > > So I don't know about temp sensors - I'm talking about amd_nb which is > something... well, I explained already what it is in my previous mail so > I won't repeat myself. > > Anyway, if there is such a PNP ID device - and I believe I have stumbled > upon some blurb about it in the BKDGs - which says "this device > represents the PCI device IDs of a CPU" and if that can be used to > register amd_nb through it, then sure, I don't see why not. > > This way, when new CPU comes out and the same PNP ID device is present, > amd_nb would load, sure. No, the idea was more that that temp monitoring, e.g., k10temp, could be independent of amd_nb. But I can tell this idea isn't going anywhere, so let's just forget that I stuck my neck out and let it die on the vine :) Bjorn