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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E453CC433C1 for ; Wed, 24 Mar 2021 15:35:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B97A761A09 for ; Wed, 24 Mar 2021 15:35:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236697AbhCXPep (ORCPT ); Wed, 24 Mar 2021 11:34:45 -0400 Received: from mx2.suse.de ([195.135.220.15]:45108 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236629AbhCXPeM (ORCPT ); Wed, 24 Mar 2021 11:34:12 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C2AD5AD9F; Wed, 24 Mar 2021 15:34:10 +0000 (UTC) Message-ID: <78dec30c052e9bb76e52c38f3da5af371e5d65f5.camel@suse.de> Subject: Re: [PATCH 4/4] ARM: dts: Fix-up EMMC2 controller's frequency From: Nicolas Saenz Julienne To: Stefan Wahren , Nicolas Saenz Julienne , linux-arm-kernel@lists.infradead.org, linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, linux-rpi-kernel@lists.infradead.org, Rob Herring Cc: f.fainelli@gmail.com, phil@raspberrypi.com, tim.gover@raspberrypi.com, adrian.hunter@intel.com, sbranden@broadcom.com, alcooperx@gmail.com, linux-kernel@vger.kernel.org, ulf.hansson@linaro.org Date: Wed, 24 Mar 2021 16:34:09 +0100 In-Reply-To: <401100ea-90ad-57b1-50da-967118a090da@i2se.com> References: <20210322185816.27582-1-nsaenz@kernel.org> <20210322185816.27582-5-nsaenz@kernel.org> <401100ea-90ad-57b1-50da-967118a090da@i2se.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-FFEARCZYyZSHobHLGWfZ" User-Agent: Evolution 3.38.4 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org --=-FFEARCZYyZSHobHLGWfZ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Stefan, On Wed, 2021-03-24 at 16:16 +0100, Stefan Wahren wrote: > Hi Nicolas, >=20 > Am 22.03.21 um 19:58 schrieb Nicolas Saenz Julienne: > > From: Nicolas Saenz Julienne > >=20 > > Force emmc2's frequency to 150MHz as the default 100MHz (set by FW) > > seems to interfere with the VPU clock when setup at frequencies bigger > > than 500MHz (a pretty common case). This ends up causing unwarranted > > SDHCI CMD hangs when no SD card is present. > >=20 > > Signed-off-by: Nicolas Saenz Julienne > > --- > > =C2=A0arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 6 ++++++ > > =C2=A01 file changed, 6 insertions(+) > >=20 > > diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/= bcm2711-rpi-4-b.dts > > index 3b4ab947492a..9aa8408d9960 100644 > > --- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts > > +++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts > > @@ -257,6 +257,12 @@ &emmc2 { > > =C2=A0 vqmmc-supply =3D <&sd_io_1v8_reg>; > > =C2=A0 vmmc-supply =3D <&sd_vcc_reg>; > > =C2=A0 broken-cd; > > + /* > > + * Force the frequency to 150MHz as the default 100MHz seems to > > + * interfere with the VPU clock when setup at frequencies bigger than > > + * 500MHz, causing unwarranted CMD hangs. > > + */ > > + clock-frequency =3D <150000000>; >=20 > i don't want to bike-shed here, but is there any chance to solve this in > clk-bcm2835 in a less hacky way? What do you have in mind? All I can think of is adding some kind of heuristic to the clock's prepare(= ) callback. That said, I don't feel it would be a better solution than this. Regards, Nicolas --=-FFEARCZYyZSHobHLGWfZ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEErOkkGDHCg2EbPcGjlfZmHno8x/4FAmBbW/EACgkQlfZmHno8 x/67jAgAkEAjGxqXoq4Ga/ry0PqEcfUiGD4+CRAlqZtglOAj2WqZ5z6CRwxg6Xt5 LYDxIoLjBAENrkkjbMv4nQPdLLDvf3UjBeRTK70mfsON7Pt6HLk3fxAws/36/1DK AAMprq5BVCTNY04+tjdQvV0A/w6o71aQF74ghlytDlP2fm7jS6WcEqRLIkuGqe7U dXtOGwt7SPJGevPbktCQff7xLJ5Aw4W0+JHoM3nxDIdiA3hpOFvuQSQbn90OpCTf P4O9cbCFQ4Am60dYBmGAIuV3jGpkB4PZk8wJms+ePiTGtZBso5eorU1jyqKbZAOd kB4wrjXd1OrQbZB87A5SELjhUUa1FQ== =qWwb -----END PGP SIGNATURE----- --=-FFEARCZYyZSHobHLGWfZ--