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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 DAA4AC0044C for ; Wed, 7 Nov 2018 16:07:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD83720827 for ; Wed, 7 Nov 2018 16:07:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AD83720827 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=alien8.de 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 S1728098AbeKHBiU (ORCPT ); Wed, 7 Nov 2018 20:38:20 -0500 Received: from mail.skyhub.de ([5.9.137.197]:44498 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727668AbeKHBiU (ORCPT ); Wed, 7 Nov 2018 20:38:20 -0500 X-Virus-Scanned: Nedap ESD1 at mail.skyhub.de Received: from mail.skyhub.de ([127.0.0.1]) by localhost (blast.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id lK5pCVWiX6yr; Wed, 7 Nov 2018 17:07:20 +0100 (CET) Received: from zn.tnic (p200300EC2BCBE000329C23FFFEA6A903.dip0.t-ipconnect.de [IPv6:2003:ec:2bcb:e000:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 180A51EC0402; Wed, 7 Nov 2018 17:07:20 +0100 (CET) Date: Wed, 7 Nov 2018 17:07:07 +0100 From: Borislav Petkov To: Bjorn Helgaas , "Woods, Brian" Cc: 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: <20181107160707.GA14169@zn.tnic> References: <20181102181055.130531-3-brian.woods@amd.com> <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> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20181107133856.GA238955@google.com> 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 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. Maybe Brian knows more on the subject... -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.