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 7ECA3C4167B for ; Fri, 1 Dec 2023 19:20:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379518AbjLATUT (ORCPT ); Fri, 1 Dec 2023 14:20:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379411AbjLATUR (ORCPT ); Fri, 1 Dec 2023 14:20:17 -0500 Received: from fllv0015.ext.ti.com (fllv0015.ext.ti.com [198.47.19.141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4377AF2 for ; Fri, 1 Dec 2023 11:20:23 -0800 (PST) Received: from lelv0266.itg.ti.com ([10.180.67.225]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 3B1JJxSJ017110; Fri, 1 Dec 2023 13:19:59 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1701458399; bh=4hE0ULmqeZ9UHjJRy8A8SQgh9lDr0tGQ6QM7S2mBOaI=; h=Date:From:To:CC:Subject:References:In-Reply-To; b=iOok+rK5zroDJMumbpaL41DjCkuMdF3uyFDHl/Awo+PxUDY2udKJM5to5TEd5SqjC ctjsXlV1rc2+LkSdU04ImQIjFtCibXYqMQOTCxPoNor14l8t8nOHtOjRqtN/IPH4JR 9eyd820VtCrWZRZC8NMSNOoI8mkzlcEaKDvv1X6Q= Received: from DFLE111.ent.ti.com (dfle111.ent.ti.com [10.64.6.32]) by lelv0266.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 3B1JJxLI046494 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 1 Dec 2023 13:19:59 -0600 Received: from DFLE111.ent.ti.com (10.64.6.32) by DFLE111.ent.ti.com (10.64.6.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23; Fri, 1 Dec 2023 13:19:58 -0600 Received: from lelv0327.itg.ti.com (10.180.67.183) by DFLE111.ent.ti.com (10.64.6.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23 via Frontend Transport; Fri, 1 Dec 2023 13:19:58 -0600 Received: from localhost (ileaxei01-snat.itg.ti.com [10.180.69.5]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id 3B1JJwpU012447; Fri, 1 Dec 2023 13:19:58 -0600 Date: Fri, 1 Dec 2023 13:19:58 -0600 From: Nishanth Menon To: Francesco Dolcini CC: , , Arnd Bergmann , Vignesh Raghavendra , Catalin Marinas , Will Deacon , Tero Kristo , Tony Lindgren Subject: Re: [PATCH v2] arm64: defconfig: increase SERIAL_8250_NR_UARTS Message-ID: <20231201191958.kmwkpmttmebsas47@kooky> References: <20231201171544.1901-1-francesco@dolcini.it> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20231201171544.1901-1-francesco@dolcini.it> X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18:15-20231201, Francesco Dolcini wrote: > Increase CONFIG_SERIAL_8250_NR_UARTS from 4 to 8, the current legacy value > is not adequate for embedded systems that use SoCs where it's common to > have a large number of serial ports. > > No need to change CONFIG_SERIAL_8250_RUNTIME_UARTS, see commit 9d86719f8769 > ("serial: 8250: Allow using ports higher than SERIAL_8250_RUNTIME_UARTS"). > > The need to increase this value was noticed while working with Toradex > Verdin AM62, this board has 4 serial UART instances available to the user > plus an internal one that is connected to a Bluetooth module. Without this > change the fifth UART connected to the BT module is not instantiated and BT > is not working. > > Instead of increasing the number to the bare minimum (5) that would be > required to solve this specific issue, we increase this to 8 which seems a > more reasonable number to have in the defconfig and should cover more valid > use cases. To address Arnd's concern on size increase, it will be good to add: --- With this change kernel image increases by ~3.2k. bloat-o-meter summary: add/remove: 1/1 grow/shrink: 7/0 up/down: 3220/-8 (3212) --- Full bloat-o-meter report: aarch64-none-linux-gnu-gcc (11.3.1 20220712) $ ./scripts/bloat-o-meter ./vmlinux.old vmlinux add/remove: 1/1 grow/shrink: 7/0 up/down: 3220/-8 (3212) Function old new delta serial8250_ports 3136 6272 +3136 serial8250_register_8250_port 1176 1208 +32 serial8250_remove 120 136 +16 serial8250_unregister_port 288 296 +8 serial8250_suspend 120 128 +8 serial8250_setup_port 212 220 +8 e843419@0d28_000102dd_3a64 - 8 +8 serial8250_init 468 472 +4 e843419@0c0a_0000eb9e_8cc 8 - -8 Total: Before=28756614, After=28759826, chg +0.01% > > Cc: Tony Lindgren > Reviewed-by: Tony Lindgren > Signed-off-by: Francesco Dolcini > --- > arch/arm64/configs/defconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig > index b60aa1f89343..ecd365cd1d87 100644 > --- a/arch/arm64/configs/defconfig > +++ b/arch/arm64/configs/defconfig > @@ -448,6 +448,7 @@ CONFIG_SERIO_AMBAKMI=y > CONFIG_LEGACY_PTY_COUNT=16 > CONFIG_SERIAL_8250=y > CONFIG_SERIAL_8250_CONSOLE=y > +CONFIG_SERIAL_8250_NR_UARTS=8 > CONFIG_SERIAL_8250_EXTENDED=y > CONFIG_SERIAL_8250_SHARE_IRQ=y > CONFIG_SERIAL_8250_BCM2835AUX=y > -- > 2.39.2 > -- Regards, Nishanth Menon Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3 1A34 DDB5 849D 1736 249D