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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 92934C433B4 for ; Wed, 14 Apr 2021 13:42:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7B31A611B0 for ; Wed, 14 Apr 2021 13:42:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232844AbhDNNmg (ORCPT ); Wed, 14 Apr 2021 09:42:36 -0400 Received: from wout5-smtp.messagingengine.com ([64.147.123.21]:48253 "EHLO wout5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230477AbhDNNmg (ORCPT ); Wed, 14 Apr 2021 09:42:36 -0400 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.west.internal (Postfix) with ESMTP id EE1F51687; Wed, 14 Apr 2021 09:42:13 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute5.internal (MEProxy); Wed, 14 Apr 2021 09:42:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sholland.org; h= subject:to:references:from:message-id:date:mime-version :in-reply-to:content-type:content-transfer-encoding; s=fm2; bh=S q+aFQYu85UJZAAI/3lU2S/K+bPFlpctOhTGjYKZApA=; b=MkTHDEEZhPOaH0Zip 7RN9Z/f+atP0Hk5MLf9vDu+r7HRFVj20uoaEQP61DWrLDGq0xImTsCjoaSsvaHHB 09DyTwH9bqcWgc5jCZS+WAqFowNK58ASS7DmhuqjyzX70z4A3a7RKH6uydhhUVJr FUt5KpEnhZhC/4vWWJFShiE/PwJNn5QSnwOMDE/X9+sK07mNPE+BqXGrUR9RLwqd arhF8uKu0GpdP3mMQICt/CvdH6HTXoVDtoKEDiabrUvvlNO3JvuW/g5N2YfxqSyy xdKPxW5DF0fcpUxA3OPSUtjkZc31EfLpMVAyfkbhdkA2pmzxh7qlRfpgQEoXM7bV lr0aw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm2; bh=Sq+aFQYu85UJZAAI/3lU2S/K+bPFlpctOhTGjYKZA pA=; b=Scn0DUKOtZP2XyCw3Pc4E9J/EUlS5Kfn2XB3CZdDeO0GHJFQ2A1uVDwJM 8oxKZ/ml/CDfb3ioGdw/iF/lVGFek6eZFdSlCTEw1ZZqCfFVy8+aUo1nDMmKwssH fbhAMUl+4csJ7hNR7oSdRrq8UAlXEKJUe3vsbQ6s5iJwjQKxJzD3SEvRlZqtpBWI d8xQdtTvTe+8ycosjXvzDRwAZm7PQsuQE7kOLRMpkRNF7L6xwWzWWZPFCFnwXLrk 9TEG/W2LUFSFXuzmUnBJTvMnQmBOm5oh/5ZPNcwwnD6GDJ/hjoShktOiQVJ+/4FN 4Igdxi7kqasDYZi1xr5bLp7dMcHew== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrudeluddgieekucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepuffvfhfhkffffgggjggtgfesthekredttdefjeenucfhrhhomhepufgrmhhu vghlucfjohhllhgrnhguuceoshgrmhhuvghlsehshhholhhlrghnugdrohhrgheqnecugg ftrfgrthhtvghrnhepgfelkeduveejtdejhfeiledvhfeggeeiieeklefhfeefffffffeg udetteelieejnecukfhppeejtddrudefhedrudegkedrudehudenucevlhhushhtvghruf hiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpehsrghmuhgvlhesshhhohhllhgr nhgurdhorhhg X-ME-Proxy: Received: from [192.168.50.169] (70-135-148-151.lightspeed.stlsmo.sbcglobal.net [70.135.148.151]) by mail.messagingengine.com (Postfix) with ESMTPA id 8BA26240057; Wed, 14 Apr 2021 09:42:12 -0400 (EDT) Subject: Re: [PATCH] i2c: mv64xxx: Fix random system lock caused by runtime PM To: Wolfram Sang , =?UTF-8?Q?Marek_Beh=c3=ban?= , Gregory CLEMENT , linux-i2c@vger.kernel.org, Ondrej Jirman References: <20210408020000.21914-1-kabel@kernel.org> <20210413195854.GB2751@kunai> From: Samuel Holland Message-ID: <01f2a007-39d8-d7c0-b3bc-ef379956d43e@sholland.org> Date: Wed, 14 Apr 2021 08:42:11 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20210413195854.GB2751@kunai> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On 4/13/21 2:58 PM, Wolfram Sang wrote: > On Thu, Apr 08, 2021 at 04:00:00AM +0200, Marek Behún wrote: >> I noticed a weird bug with this driver on Marvell CN9130 Customer >> Reference Board. >> >> Sometime after boot, the system locks with the following message: >> [104.071363] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 >> >> The system does not respond afterwards, only warns about RCU stalls. >> >> This first appeared with commit e5c02cf54154 ("i2c: mv64xxx: Add runtime >> PM support"). >> >> With further experimentation I discovered that adding a delay into >> mv64xxx_i2c_hw_init() fixes this issue. This function is called before >> every xfer, due to how runtime PM works in this driver. It seems that in >> order to work correctly, a delay is needed after the bus is reset in >> this function. >> >> Since there already is a known erratum with this controller needing a >> delay, I assume that this is just another place this needs to be >> applied. Therefore I apply the delay only if errata_delay is true. >> >> Signed-off-by: Marek Behún > > Gregory? Looks reasonable to me and if so, we should have this in 5.12 > already. Comments from others are welcome, too, of course. I also don't have an affected platform, so I did not notice this when adding runtime PM. The change makes sense to me as well. Reviewed-by: Samuel Holland Cheers, Samuel >> --- >> drivers/i2c/busses/i2c-mv64xxx.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c >> index c590d36b5fd1..5c8e94b6cdb5 100644 >> --- a/drivers/i2c/busses/i2c-mv64xxx.c >> +++ b/drivers/i2c/busses/i2c-mv64xxx.c >> @@ -221,6 +221,10 @@ mv64xxx_i2c_hw_init(struct mv64xxx_i2c_data *drv_data) >> writel(0, drv_data->reg_base + drv_data->reg_offsets.ext_addr); >> writel(MV64XXX_I2C_REG_CONTROL_TWSIEN | MV64XXX_I2C_REG_CONTROL_STOP, >> drv_data->reg_base + drv_data->reg_offsets.control); >> + >> + if (drv_data->errata_delay) >> + udelay(5); >> + >> drv_data->state = MV64XXX_I2C_STATE_IDLE; >> } >> >> -- >> 2.26.2 >>