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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 177BBC5CFF1 for ; Tue, 12 Jun 2018 08:40:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB245208B1 for ; Tue, 12 Jun 2018 08:40:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB245208B1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934052AbeFLIkm (ORCPT ); Tue, 12 Jun 2018 04:40:42 -0400 Received: from mga17.intel.com ([192.55.52.151]:39362 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933363AbeFLIki (ORCPT ); Tue, 12 Jun 2018 04:40:38 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Jun 2018 01:40:37 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,213,1526367600"; d="scan'208";a="47085193" Received: from shbuild888.sh.intel.com (HELO localhost) ([10.239.146.239]) by fmsmga008.fm.intel.com with ESMTP; 12 Jun 2018 01:40:36 -0700 Date: Tue, 12 Jun 2018 16:42:34 +0800 From: Feng Tang To: Ulf Hansson Cc: Linux Kernel Mailing List , "linux-mmc@vger.kernel.org" , Greg Kroah-Hartman , Adrian Hunter Subject: Re: [PATCH] mmc: Move the mmc driver init earlier Message-ID: <20180612084234.gjzq66xsqblryrkm@shbuild888> References: <20180608095154.22413-1-feng.tang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ulf, Thanks for the review. On Tue, Jun 12, 2018 at 08:25:44AM +0200, Ulf Hansson wrote: > On 8 June 2018 at 11:51, Feng Tang wrote: > > When doing some boot time optimization for an eMMC rootfs NUCs, > > we found the rootfs may spend around 100 microseconds waiting > > for eMMC card to be initialized, then the rootfs could be > > mounted. > > [ 1.216561] Waiting for root device /dev/mmcblk1p1... > > [ 1.289262] mmc1: new HS400 MMC card at address 0001 > > [ 1.289667] mmcblk1: mmc1:0001 R1J56L 14.7 GiB > > [ 1.289772] mmcblk1boot0: mmc1:0001 R1J56L partition 1 8.00 MiB > > [ 1.289869] mmcblk1boot1: mmc1:0001 R1J56L partition 2 8.00 MiB > > [ 1.289967] mmcblk1rpmb: mmc1:0001 R1J56L partition 3 4.00 MiB > > [ 1.292798] mmcblk1: p1 p2 p3 > > [ 1.300576] EXT4-fs (mmcblk1p1): couldn't mount as ext3 due to feature incompatibilities > > [ 1.300912] EXT4-fs (mmcblk1p1): couldn't mount as ext2 due to feature incompatibilities > > > > And this is a common problem for smartphones, tablets, embedded > > devices and automotive products. This patch will make the eMMC/SD > > card start initializing earlier, by changing its order in drivers/Makefile. > > > > On our platform, the waiting for eMMC card is almost eliminated with the patch, > > which is critical to boot time. > > I am wondering what kernel version you are running here. There have > been some changes to the mmc initialization path, which perhaps can > help. These logs in commit msg are based on kernel 4.14, and the patch is generated against kernel 4.17. > > > > > Signed-off-by: Feng Tang > > --- > > drivers/Makefile | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/Makefile b/drivers/Makefile > > index 24cd47014657..c473afd3c688 100644 > > --- a/drivers/Makefile > > +++ b/drivers/Makefile > > @@ -50,6 +50,9 @@ obj-$(CONFIG_REGULATOR) += regulator/ > > # reset controllers early, since gpu drivers might rely on them to initialize > > obj-$(CONFIG_RESET_CONTROLLER) += reset/ > > > > +# put mmc early as many morden devices use emm/sd card as rootfs storage > > +obj-y += mmc/ > > + > > Your suggested approach isn't really a solution, as it may work for > your particular case but not for everybody else. Do you mean the patch may break some platforms? Yes, I only tested on some IA based NUCs, and I did think about other architectures, things that may affect MMC are gpio/clk/pinctrl, and those are still earlier than mmc after change. Thanks, Feng