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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 48CE6C433B4 for ; Tue, 13 Apr 2021 19:58:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 225FA613C1 for ; Tue, 13 Apr 2021 19:58:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231802AbhDMT7S (ORCPT ); Tue, 13 Apr 2021 15:59:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:45716 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230244AbhDMT7S (ORCPT ); Tue, 13 Apr 2021 15:59:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5F74F613CA; Tue, 13 Apr 2021 19:58:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618343938; bh=5bddcdQJZV2HK/VysiMwp2703Aq6rjJ1j6rCQCWbhLs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=f8/OKm6v57j03Z47qRJY13vjZEfcqeDehdig8mpIvd+b2wLIniwGslXK+23oqTWkj bOK8D0B2ypX6P40FgwI6w8cft36esrsAt32f1rPH4BN+/VaGtpcbI5jzo2X/EuAdVF /i1+YzuO5Coy+eSkmPWOszZpesjPI/1aBqdkzOOE0ezk3Cr+365lITUp9FtyB6oqva bKjoneYkPR+HljfQ2brQyv4glsaUh9FN6v6ZatSQD6jE829wOYriCjgdDmv5nLcA2U bUi9/tep4JSxyBm6wpb6tQJQ8Jr0TEP40bFS5YidI/Sv+g/Hxy/4IRBphJeX9dx1Fp d94eWhMzk9qnQ== Date: Tue, 13 Apr 2021 21:58:54 +0200 From: Wolfram Sang To: Marek =?utf-8?B?QmVow7pu?= , Gregory CLEMENT Cc: linux-i2c@vger.kernel.org, Samuel Holland , Ondrej Jirman Subject: Re: [PATCH] i2c: mv64xxx: Fix random system lock caused by runtime PM Message-ID: <20210413195854.GB2751@kunai> Mail-Followup-To: Wolfram Sang , Marek =?utf-8?B?QmVow7pu?= , Gregory CLEMENT , linux-i2c@vger.kernel.org, Samuel Holland , Ondrej Jirman References: <20210408020000.21914-1-kabel@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="FkmkrVfFsRoUs1wW" Content-Disposition: inline In-Reply-To: <20210408020000.21914-1-kabel@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org --FkmkrVfFsRoUs1wW Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Apr 08, 2021 at 04:00:00AM +0200, Marek Beh=C3=BAn wrote: > I noticed a weird bug with this driver on Marvell CN9130 Customer > Reference Board. >=20 > Sometime after boot, the system locks with the following message: > [104.071363] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 >=20 > The system does not respond afterwards, only warns about RCU stalls. >=20 > This first appeared with commit e5c02cf54154 ("i2c: mv64xxx: Add runtime > PM support"). >=20 > 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. >=20 > 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. >=20 > Signed-off-by: Marek Beh=C3=BAn Gregory? Looks reasonable to me and if so, we should have this in 5.12 already. Comments from others are welcome, too, of course. > --- > drivers/i2c/busses/i2c-mv64xxx.c | 4 ++++ > 1 file changed, 4 insertions(+) >=20 > diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv= 64xxx.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_dat= a) > 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 =3D MV64XXX_I2C_STATE_IDLE; > } > =20 > --=20 > 2.26.2 >=20 --FkmkrVfFsRoUs1wW Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAmB19/4ACgkQFA3kzBSg KbZ0uw//U7Bl9nR2Gbar+SfrDajWg6geFRUjr4X42Qi4w5leFfRzr81aTMUk9rFm QHk/0NiG5RH9lAzBLE8jTILcladqNVlBrGYUDqQkXGFZlyKDU5EaLG90rxX6r7h/ KRGpIl5iq5gYla+S4E2GYRka/dTe3UAV6QG40dPnQRKdO2YVpXb3VDxRGTlwqlzV r/EInqFq4z4OPX+4uob+qujKVW6diQbIOT4XVd27yrrME2xUX9HYOpwwhYCOkAwN y2isE5qQz5X2zp3RTdvPGAGfLo6EJ43S30xl9Vn+P2tknFZBG1TJ8ydhuMSvHRI2 eeZMazkZN+AiHPvMo78+uWbzJIghPlf7rIN7xHpQumJq9fA4uYsaNZfQPUUeqM8P Pd2V4kute8JF4Kj15hXdNjmOCttEhhYlNa9SAjz0Z93SDFvA+kZwUuNJT75FTtuA JhNJF+24mS8Hxaf9/ixLYEjXuzoJu45JwdTNQk88R8i/rGXfb4INYVdiqaGfRQjI 2uzLY50cYJR1olcBizQq8LQCBb5rkPOCCvUTcpgPbkrs8ZGrFF4qYtHKqsU5mmKX 3L6fiBcRCUjE6TCSqnn6gX9MGdm5JquavM+vDEGpFhdwdMGnjjre4ioBU9YteGI/ 3x7ZPOz3U4u1YjkA5Dhp6z7VnDtm9w2u3BfGmiI1KWpldl0tTGQ= =r1xV -----END PGP SIGNATURE----- --FkmkrVfFsRoUs1wW--