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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7ED03CD98CE for ; Fri, 12 Jun 2026 15:44:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ftGeg50CGe9xz7E7JfMoLIbNd3f4BkCApA9FnTerMy0=; b=P1Bi1gbSnmn2nVS6fCryhEJLWy RFvh74JNbRZlJnKmAkHn5tvNvnFLFfQenv4OZS7R9GF2AJGL/iJ5L4dv9bBOVPoh25twLnjwi/n88 jkqeEA6J4DdxjlvyPt7Th6xqDEQhlhew76pWTzlUIP2XlljSUF9qxAfFlbCy0jbKdpstkPPyKUIFz OOfmEdK4UY6x2qMRcXJBNIllFW4nUSG7gXzwj8jL11/yaNJj1gtJUVqv+/xl07/iQc4Fu0Bxn1bD5 ahSAEDrxPycTl/yqLNmhp/KrgpwkjLXh/4vZ7Px5g9jPJZ0xJibQ1KKZszCYYoVKgqfAUL+cREUMo hs72t4wg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wY43G-0000000BAn3-17cN; Fri, 12 Jun 2026 15:44:10 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wY43D-0000000BAmq-2sQ0; Fri, 12 Jun 2026 15:44:08 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 6998D6008A; Fri, 12 Jun 2026 15:44:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2CD361F000E9; Fri, 12 Jun 2026 15:44:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781279046; bh=Ua7ilpqGQ1TJZ+Bnhifl0cs54R7li+gA4PLtG5KdeuQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=h91m9/RTVoc4n7+PHfPlE/bu8XLven6nAKb35XV39yApAjaHBXzKJ8LUiHX1Ax3Uc hs+12QVOwd6kjjJHbtVqYUbhAHbpwTwAT5pFJ1nP+Sh0z/nfy0DvOJYNcBQNju/VQ8 P04Ynl5UWyd/Y7FiICFoenOJs8qje3zDwnbGwSrCRteIPXWRqJ+I5RPoff7YUeQKum 036rNdlfFTMd8xwP8TnkpAhJ8pars/jTvXV2Gk1guqSQ4I9+GOgKudR2CLNTsWKdV3 iLGdyKn3IuvIXLxhLCWAjcln79zQPU1A7k5OmuBwMgVtAKBb5X12h4oXaUeQjm/24M 9ALyckPrchIYg== Date: Fri, 12 Jun 2026 16:44:00 +0100 From: Conor Dooley To: Vladimir Oltean Cc: linux-phy@lists.infradead.org, devicetree@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, Ioana Ciornei , Vinod Koul , Neil Armstrong , Tanjeff Moos , "Christophe Leroy (CS GROUP)" , Michael Walle , Shawn Guo , Frank Li , linux-kernel@vger.kernel.org, Krzysztof Kozlowski , Rob Herring Subject: Re: [PATCH v1 phy-next 6/8] dt-bindings: fsl: layerscape-dcfg: define DCFG_DCSR region Message-ID: <20260612-graveyard-hacked-c65d54a1ece8@spud> References: <20260611193940.44416-1-vladimir.oltean@nxp.com> <20260611193940.44416-7-vladimir.oltean@nxp.com> MIME-Version: 1.0 In-Reply-To: <20260611193940.44416-7-vladimir.oltean@nxp.com> X-BeenThere: linux-phy@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux Phy Mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============8203861088378344239==" Sender: "linux-phy" Errors-To: linux-phy-bounces+linux-phy=archiver.kernel.org@lists.infradead.org --===============8203861088378344239== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Anvk3G/afIgQqFuh" Content-Disposition: inline --Anvk3G/afIgQqFuh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 11, 2026 at 10:39:38PM +0300, Vladimir Oltean wrote: > In Layerscape (Arm) and QorIQ (PowerPC) devices, hardware peripherals > are accessed by the CPU through a portion of the SoC address space > called CCSR ("Configuration, Control, and Status Registers"). All > hardware IP blocks have their registers mapped here, and the Device > Configuration block makes no exception. >=20 > However, there exists a secondary range of the address space named DCSR > ("Debug Control and Status Registers") which, like CCSR, also holds > registers of hardware IP blocks, except the DCSR contents is hidden in > all public reference manuals. >=20 > The intention of the CCSR/DCSR split, to the best of my knowledge, was > to place the functionality that is too low level for normal use, and > which is necessary only for debug, in a completely separate address > space which can be hidden. >=20 > A use case has appeared where networking SerDes lanes need to be > reconfigured at runtime for a different protocol (example: 10GBase-R to > SGMII), and the architecture of the SoCs does not normally permit that. > The Reset Configuration Word (RCW) is a data structure read by the SoC > preboot loader (PBL) which contains stuff like pinmuxing and SerDes > protocol mapping for each lane. >=20 > The RCW that the PBL has loaded is visible in the DCFG block's normal > status registers (from CCSR), as read only. Turns out, the RCW is also > mapped in the DCFG's shadow register map (in DCSR), in a write-only > form. Writing to the RCW registers from the DCFG's DCSR space to change > what the PBL has loaded is called "RCW override". >=20 > It has been validated that the RCW override procedure is necessary to > reconfigure the networking data path when a SerDes lane performs a major > protocol change. It changes some internal muxes which connect the PCS to > either the 10G MAC or to the 1G MAC. >=20 > Defining the DCSR area of the DCFG as a secondary 'reg' array element > allows operating systems to perform RCW overrides. Since it is > introduced late in the binding's lifetime, it is optional. It can be > identified by name, but also by index (first 'reg' is CCSR). >=20 > Note that while all SoCs should have a DCFG register block in DCSR, we > only need to expose it for the SoCs where the RCW override procedure is > known to be needed and has been validated. >=20 > Signed-off-by: Vladimir Oltean > --- > Cc: Conor Dooley Where did this email come from btw? get_maintainer.pl result should have +dt in it. Reviewed-by: Conor Dooley pw-bot: not-applicable Cheers, Conor. > Cc: Krzysztof Kozlowski > Cc: Rob Herring > Cc: devicetree@vger.kernel.org > --- > .../bindings/soc/fsl/fsl,layerscape-dcfg.yaml | 15 ++++++++++++++- > 1 file changed, 14 insertions(+), 1 deletion(-) >=20 > diff --git a/Documentation/devicetree/bindings/soc/fsl/fsl,layerscape-dcf= g.yaml b/Documentation/devicetree/bindings/soc/fsl/fsl,layerscape-dcfg.yaml > index 3fb0534ea597..fc14fd0bf84b 100644 > --- a/Documentation/devicetree/bindings/soc/fsl/fsl,layerscape-dcfg.yaml > +++ b/Documentation/devicetree/bindings/soc/fsl/fsl,layerscape-dcfg.yaml > @@ -36,7 +36,20 @@ properties: > - const: simple-mfd > =20 > reg: > - maxItems: 1 > + minItems: 1 > + items: > + - description: > + Customer-visible DCFG register map from CCSR address space > + (Configuration, Control and Status Registers) > + - description: > + Customer-hidden DCFG register map from DCSR address space > + (Debug Control and Status Registers) > + > + reg-names: > + minItems: 1 > + items: > + - const: dcfg_ccsr > + - const: dcfg_dcsr > =20 > little-endian: true > big-endian: true > --=20 > 2.34.1 >=20 --Anvk3G/afIgQqFuh Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCaiwpPQAKCRB4tDGHoIJi 0iTkAP4y8yskNE7dxgDzs/Wxh5ly8vIUHNi1EsapV2wtvfvMrwEA//4T48+aL7mC /esW1vHzfucr882C38bIUCbZewcjhgE= =NKQc -----END PGP SIGNATURE----- --Anvk3G/afIgQqFuh-- --===============8203861088378344239== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline -- linux-phy mailing list linux-phy@lists.infradead.org https://lists.infradead.org/mailman/listinfo/linux-phy --===============8203861088378344239==--