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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7FEE3C433EF for ; Wed, 29 Jun 2022 20:36:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230027AbiF2UgI (ORCPT ); Wed, 29 Jun 2022 16:36:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229492AbiF2UgI (ORCPT ); Wed, 29 Jun 2022 16:36:08 -0400 Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 733CA313BD; Wed, 29 Jun 2022 13:36:06 -0700 (PDT) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 25TKS467028346; Wed, 29 Jun 2022 15:28:04 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 25TKS1wF028345; Wed, 29 Jun 2022 15:28:01 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Wed, 29 Jun 2022 15:28:01 -0500 From: Segher Boessenkool To: Krzysztof Kozlowski Cc: Ash Logan , krzysztof.kozlowski+dt@linaro.org, paulus@samba.org, mpe@ellerman.id.au, christophe.leroy@csgroup.eu, robh+dt@kernel.org, benh@kernel.crashing.org, devicetree@vger.kernel.org, linkmauve@linkmauve.fr, linux-kernel@vger.kernel.org, rw-r-r-0644@protonmail.com, joel@jms.id.au, linuxppc-dev@lists.ozlabs.org, j.ne@posteo.net Subject: Re: [PATCH v3 02/12] powerpc: wiiu: device tree Message-ID: <20220629202800.GJ25951@gate.crashing.org> References: <20220622131037.57604-1-ash@heyquark.com> <20220628133144.142185-1-ash@heyquark.com> <20220628133144.142185-3-ash@heyquark.com> <20220629161302.GG25951@gate.crashing.org> <908e7555-0090-84fe-4227-d6b349de1394@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <908e7555-0090-84fe-4227-d6b349de1394@linaro.org> User-Agent: Mutt/1.4.2.3i Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Wed, Jun 29, 2022 at 08:13:13PM +0200, Krzysztof Kozlowski wrote: > On 29/06/2022 18:13, Segher Boessenkool wrote: > > On Wed, Jun 29, 2022 at 11:58:18AM +0200, Krzysztof Kozlowski wrote: > >>> + /* TODO: Add SMP */ > >>> + PowerPC,espresso@0 { > >> > >> Node name should be generic, so "cpu". Unless something needs the > >> specific node name? > > > > This is how most other PowerPC firmwares do it. The PowerPC processor > > binding is older than the generic naming practice, so CPU nodes have > > device_type "cpu" instead. > > ePAPR 1.0 from 2008 explicitly asks for generic node names. So 4 years > before Nintento Wii U. Maybe earlier ePAPR-s were also asking for this, > no clue, don't have them. The majority of PowerPC 750 systems long predate that. Many *current* systems implement the PowerPC Processor Binding, too (not the epapr thing, which is incompatible with the older standards!) > > There is no added value in generic naming for CPU nodes anyway, since > > you just find them as the children of the "/cpus" node :-) > > There is because you might have there caches. It also makes code easier > to read. In the processor binding the cache nodes were subnodes of cpu nodes or other cache nodes. But in some server products you can have cache that is enabled while the corresponding core is disabled; and also, not all cache belongs to only one higher level anyway. This was modelled pretty uncleanly, yup (cleaner would have been to have a /caches node as well as /cpus, for example). But on 750 you just have "l2-cache" subnodes, and all nodes in /cpus are CPUs :-) Segher