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 45C2BC43217 for ; Fri, 18 Nov 2022 21:08:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229631AbiKRVIk (ORCPT ); Fri, 18 Nov 2022 16:08:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229514AbiKRVIj (ORCPT ); Fri, 18 Nov 2022 16:08:39 -0500 Received: from fllv0016.ext.ti.com (fllv0016.ext.ti.com [198.47.19.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8741F12636; Fri, 18 Nov 2022 13:08:36 -0800 (PST) Received: from fllv0035.itg.ti.com ([10.64.41.0]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 2AIL8Pjs098709; Fri, 18 Nov 2022 15:08:25 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1668805705; bh=Yr4LSYGMtRX7f6gDoB3pzPK7VDSrGB+Mip9zdhZE6vY=; h=Date:Subject:To:CC:References:From:In-Reply-To; b=pg20JjDTtULID4xVlEvXyUlUafjzZhVP48+U3vrSY7Kj8EzhZGkbUXODNcNIUpQnR pTFqmHHd4D5Rk45dCVDgqmf8jNus6PXqlQUgS9EQWdHA51ZcMjgWVArO4cJ9dxUzzL LEUg+foyGY8CZoHE4zSnYyQA8sG71fBn1PuI0H1k= Received: from DLEE100.ent.ti.com (dlee100.ent.ti.com [157.170.170.30]) by fllv0035.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 2AIL8PhZ102998 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 18 Nov 2022 15:08:25 -0600 Received: from DLEE103.ent.ti.com (157.170.170.33) by DLEE100.ent.ti.com (157.170.170.30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.16; Fri, 18 Nov 2022 15:08:25 -0600 Received: from fllv0039.itg.ti.com (10.64.41.19) by DLEE103.ent.ti.com (157.170.170.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.16 via Frontend Transport; Fri, 18 Nov 2022 15:08:24 -0600 Received: from [10.250.38.44] (ileaxei01-snat2.itg.ti.com [10.180.69.6]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id 2AIL8Op3017735; Fri, 18 Nov 2022 15:08:24 -0600 Message-ID: <3d5e41f6-16a8-4298-ccd3-6db60f94eb47@ti.com> Date: Fri, 18 Nov 2022 15:08:23 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH v3 4/4] arm64: dts: ti: Add support for J784S4 EVM board Content-Language: en-US To: Nishanth Menon CC: Apurva Nandan , Vignesh Raghavendra , Tero Kristo , Rob Herring , Krzysztof Kozlowski , Linus Walleij , , , , , Hari Nagalla References: <20221116130428.161329-1-a-nandan@ti.com> <20221116130428.161329-5-a-nandan@ti.com> <20221118174754.y37pq77drvla2uxj@tinderbox> <8c123fa2-caab-d2dd-5eb4-688f1c6abb33@ti.com> <20221118180808.wnel7d6gswsnooww@junkman> <93242211-95e7-09a0-fced-5ef2deb9fc08@ti.com> <20221118192744.wish2vrxgy7dg7c2@unnerving> From: Andrew Davis In-Reply-To: <20221118192744.wish2vrxgy7dg7c2@unnerving> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 11/18/22 1:27 PM, Nishanth Menon wrote: > On 12:15-20221118, Andrew Davis wrote: >> I don't see either of those addressed in that thread, only that >> the aliases should go in the .dts files and be trimmed, nothing > > Key is trimmed to what the system and ecosystem needs. > >> stops us from: >> >> chosen { >> stdout-path = "serial10:115200n8"; >> }; >> >> aliases { >> serial10 = &main_uart8; >> }; > > Do we need 10 serial aliases? There are'nt 10 serial ports exposed in > j782s2. ok - lets say we do this, then: [1] is needed to boot? but why > do we need to do that for all armv8 platforms when aliases allows us Why do we need SERIAL_8250_NR_UARTS at all, might be a better question. These should be dynamically allocated if the number goes over the default count imposed by the TTY framework. Maybe folks are still a bit too afraid to touch the TTY subsystem core, I don't blame them.. > to trim it to just the 3 or 4 serial ports the platform really needs > That + being able to use the convention that serial2 is always linux > console, is'nt that a good thing? Hence recommending to just expose the > serialports as aliases to exactly what we need while keeping serial2 as > the linux console (which in this case happens to be main_uart8 - example > as j721s2 does). > "serial2 as the linux console" is *not* a convention, we just don't want to fix up our bootloader/userspace to actually reason about what serial ports to put logins on. Why not make ttyS10 the default, or ttyS666, it doesn't solve your multi-distro issue either way since they usually only start a login on ttyS0, console=, and/or the first virtual tty. Never on ttyS2. So you are hacking up DT for a solution that doesn't do what you want in the end. Andrew > [1] https://lore.kernel.org/lkml/3ab9addf-7938-fcf3-6147-15a998e37d2d@ti.com/ >