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=-14.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=no 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 7DA09C4363C for ; Fri, 2 Oct 2020 17:49:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4171320758 for ; Fri, 2 Oct 2020 17:49:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="K7c10yve" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388034AbgJBRs7 (ORCPT ); Fri, 2 Oct 2020 13:48:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387688AbgJBRs7 (ORCPT ); Fri, 2 Oct 2020 13:48:59 -0400 Received: from mail-yb1-xb41.google.com (mail-yb1-xb41.google.com [IPv6:2607:f8b0:4864:20::b41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 18B3FC0613E3 for ; Fri, 2 Oct 2020 10:48:59 -0700 (PDT) Received: by mail-yb1-xb41.google.com with SMTP id c3so1648569ybl.0 for ; Fri, 02 Oct 2020 10:48:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=QS77N6+CVhOOVc5MzAkxD23OY8NSVhkBewUyPpHdYlc=; b=K7c10yve+m/Ym4Ka9KOtXjRc9l7h/9hkwYlCtP8U1y4i6VsUSwagmYsszDYzzPWyAP doQk7cUQ9E4iFl5joVcME6pkx0+Pj0NsYO3HE/qyf6VtbK2Diua2nRDGfeOBwoWALiim +Ebyf6fiS6NK0ZzNY7ZIsUiq/eTsSs7/ZOWOi3yFac6jJuSuHA4dSGIgkHWCbpBogq9q eYFwMnw1+qz+fp/jKT6fALkj+dHmdwbAH14KNPVxicedjtSDsBGonfJnlK3l+dBoLnRC PE82kdBmi+UIMhTe/CkBfifxDFqTUbuUX0IJm9YVYH55/UwM/DFQdEknfpHW3ogGenQe rVPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=QS77N6+CVhOOVc5MzAkxD23OY8NSVhkBewUyPpHdYlc=; b=C1EMbWCAunIp08ACx5pNvmySFBvK3fuYk0/8hfL1d0BueXu04VtmKLiEwBj5uaMoPJ ERU8UmUE1ePoGaEA5miolgdk+vr6h4R14gpG9EmSh2h9NeNuQ7JmW92Hr3RldKChnfag ecyIJtDTukEc31wZ4lfjUUuU3ZdNcZZBG5hrm+N357c7NCKrk8Japf0jXOhEeJAmIfdW NeaKW/97wCiFM/LMxWzjH0gongDZf9OF5RhvlQC4gMgHNwjRiEjiJKenKUpiVkFJ/Vpg TdQNprqln/ORcS3IBvMczrpMFAfRSa1qgRxeZMnJCs0cxcvGkexGQyUKlDMzRZeEiKLK /diA== X-Gm-Message-State: AOAM533qjZRU61Cy9WbdGGibjUiemlFzttA84xo/7taDewboJwkCQQfa 7s4i8T+6QDQMjuDbO4Busx7fpPGSUM7ueoxE3KL11g== X-Google-Smtp-Source: ABdhPJyK6MpLcp9s4wybIfKzU+/XBpBlE4yS0Lf4BV1uGhjLp79GVzaBk0S/XxweTFTrs7362+sisG6zJp8OI284NSw= X-Received: by 2002:a05:6902:725:: with SMTP id l5mr4087154ybt.346.1601660938079; Fri, 02 Oct 2020 10:48:58 -0700 (PDT) MIME-Version: 1.0 References: <20201001225952.3676755-1-saravanak@google.com> <20201001231922.GG3722@pendragon.ideasonboard.com> <17bdc3f0-d816-151a-fef2-88cd38fc8621@ti.com> In-Reply-To: From: Saravana Kannan Date: Fri, 2 Oct 2020 10:48:22 -0700 Message-ID: Subject: Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path To: Grygorii Strashko Cc: Laurent Pinchart , Rob Herring , Frank Rowand , Geert Uytterhoeven , Greg Kroah-Hartman , Linux-OMAP , Linux PM , Peter Ujfalusi , "Rafael J. Wysocki" , Tomi Valkeinen , Tony Lindgren , Ulf Hansson , Android Kernel Team , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Fri, Oct 2, 2020 at 8:03 AM 'Grygorii Strashko' via kernel-team wrote: > > > > On 02/10/2020 14:40, Grygorii Strashko wrote: > > > > > > On 02/10/2020 02:19, Laurent Pinchart wrote: > >> Hi Saravana, > >> > >> Thank you for the patch. > >> > >> On Thu, Oct 01, 2020 at 03:59:51PM -0700, Saravana Kannan wrote: > >>> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when > >>> adding all top level devices") optimized the fwnode parsing when all top > >>> level devices are added, it missed out optimizing this for platform > >>> where the top level devices are added through the init_machine() path. > >>> > >>> This commit does the optimization for all paths by simply moving the > >>> fw_devlink_pause/resume() inside of_platform_default_populate(). > >> > >> Based on v5.9-rc5, before the patch: > >> > >> [ 0.652887] cpuidle: using governor menu > >> [ 12.349476] No ATAGs? > >> > >> After the patch: > >> > >> [ 0.650460] cpuidle: using governor menu > >> [ 12.262101] No ATAGs? > >> > >> :-( > > > > This is kinda expected :( because omap2 arch doesn't call of_platform_default_populate() > > > > Call path: > > board-generic.c > > DT_MACHINE_START() > > .init_machine = omap_generic_init, > > > > omap_generic_init() > > pdata_quirks_init(omap_dt_match_table); > > of_platform_populate(NULL, omap_dt_match_table, > > omap_auxdata_lookup, NULL); > > > > Other affected platforms > > arm: mach-ux500 > > some mips > > some powerpc > > > > there are also case when a lot of devices placed under bus node, in such case > > of_platform_populate() calls from bus drivers will also suffer from this issue. > > > > I think one option could be to add some parameter to _populate() or introduce new api. > > > > By the way, is there option to disable this feature at all? > > Is there Kconfig option? > > Is there any reasons why such complex and time consuming code added to the kernel and not implemented on DTC level? > > > > > > Also, I've came with another diff, pls check. > > > > [ 0.000000] Booting Linux on physical CPU 0x0 > > [ 0.000000] Linux version 5.9.0-rc6-01791-g9acba6b38757-dirty (grygorii@grygorii-XPS-13-9370) (arm-linux-gnueabihf-gcc (GNU Toolcha0 > > [ 0.000000] CPU: ARMv7 Processor [412fc0f2] revision 2 (ARMv7), cr=10c5387d > > [ 0.000000] CPU: div instructions available: patching division code > > [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache > > [ 0.000000] OF: fdt: Machine model: TI AM5718 IDK > > ... > > [ 0.053443] cpuidle: using governor ladder > > [ 0.053470] cpuidle: using governor menu > > [ 0.089304] No ATAGs? > > ... > > [ 3.092291] devtmpfs: mounted > > [ 3.095804] Freeing unused kernel memory: 1024K > > [ 3.100483] Run /sbin/init as init process > > > > > > > > ------ >< --- > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > > index 071f04da32c8..4521b26e7745 100644 > > --- a/drivers/of/platform.c > > +++ b/drivers/of/platform.c > > @@ -514,6 +514,12 @@ static const struct of_device_id reserved_mem_matches[] = { > > {} > > }; > > > > +static int __init of_platform_fw_devlink_pause(void) > > +{ > > + fw_devlink_pause(); > > +} > > +core_initcall(of_platform_fw_devlink_pause); > > + > > static int __init of_platform_default_populate_init(void) > > { > > struct device_node *node; > > @@ -538,9 +544,7 @@ static int __init of_platform_default_populate_init(void) > > } > > > > /* Populate everything else. */ > > - fw_devlink_pause(); > > of_platform_default_populate(NULL, NULL, NULL); > > - fw_devlink_resume(); > > > > return 0; > > } > > @@ -548,6 +552,7 @@ arch_initcall_sync(of_platform_default_populate_init); > > > > static int __init of_platform_sync_state_init(void) > > { > > + fw_devlink_resume(); > > ^ it seems has to be done earlier, like > +static int __init of_platform_fw_devlink_resume(void) > +{ > + fw_devlink_resume(); > + return 0; > +} > +device_initcall_sync(of_platform_fw_devlink_resume); This will mean no device will probe until device_initcall_sync(). Unfortunately, I don't think we can make such a sweeping assumption. -Saravana