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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 DE7D1C433DF for ; Wed, 27 May 2020 08:44:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6C602084C for ; Wed, 27 May 2020 08:44:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388216AbgE0Ioj (ORCPT ); Wed, 27 May 2020 04:44:39 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:40046 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388206AbgE0Iog (ORCPT ); Wed, 27 May 2020 04:44:36 -0400 Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 773482A3703; Wed, 27 May 2020 09:44:33 +0100 (BST) Date: Wed, 27 May 2020 10:44:30 +0200 From: Boris Brezillon To: Miquel Raynal Cc: Richard Weinberger , Vignesh Raghavendra , Tudor Ambarus , , Rob Herring , Mark Rutland , Subject: Re: [RESEND v5 09/21] mtd: rawnand: Create a new enumeration to describe properly ECC types Message-ID: <20200527104430.187e5feb@collabora.com> In-Reply-To: <20200527103356.56e145a9@xps13> References: <20200526195633.11543-1-miquel.raynal@bootlin.com> <20200526195633.11543-10-miquel.raynal@bootlin.com> <20200527005928.39c549e2@collabora.com> <20200527103356.56e145a9@xps13> Organization: Collabora X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Wed, 27 May 2020 10:33:56 +0200 Miquel Raynal wrote: > Boris Brezillon wrote on Wed, 27 May > 2020 00:59:28 +0200: > > > On Tue, 26 May 2020 21:56:21 +0200 > > Miquel Raynal wrote: > > > > > Now that the misleading mix between ECC engine type and OOB placement > > > has been addressed, add a new enumeration to properly define ECC types > > > (also called provider or mode). > > > > > > Signed-off-by: Miquel Raynal > > > Reviewed-by: Boris Brezillon > > > --- > > > drivers/mtd/nand/raw/nand_base.c | 7 +++++++ > > > include/linux/mtd/rawnand.h | 16 ++++++++++++++++ > > > 2 files changed, 23 insertions(+) > > > > > > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c > > > index 515cd4681660..5c6ab5b93270 100644 > > > --- a/drivers/mtd/nand/raw/nand_base.c > > > +++ b/drivers/mtd/nand/raw/nand_base.c > > > @@ -5018,6 +5018,13 @@ static const char * const nand_ecc_modes[] = { > > > [NAND_ECC_ON_DIE] = "on-die", > > > }; > > > > > > +static const char * const nand_ecc_engine_providers[] = { > > > > This table is not used here, are you sure it should be introduced now? > > > > > + [NAND_ECC_ENGINE_NONE] = "none", > > > + [NAND_ECC_ENGINE_SOFT] = "soft", > > > + [NAND_ECC_ENGINE_CONTROLLER] = "hw", > > > > ^ "on-controller" ? > > This would break DT backward compatibility, I am afraid I cannot do > that. You can always keep a translation table for the old prop (nand-ecc-mode) and have a new one for the new prop (nand-ecc-engine-type). But maybe you're not introducing a new property in this series, in which case the translation table here is just fine. > Honnestly, I find "hw" good enough because "on-controller" is > also too restrictive. How about "on-host", it doesn't say anything about where the engine is on the host (can be embedded in the controller, or an external block), yet clearly describe the fact that it's not on-die ECC. > What about an external (non-pipelined) engine > like the one I am about to introduce? > > > > > > + [NAND_ECC_ENGINE_ON_DIE] = "on-die", Well, this one is also a HW engine, and that's the problem I have with the "hw" string. > > > +}; > > > + > > > static const char * const nand_ecc_placement[] = { > > > [NAND_ECC_PLACEMENT_INTERLEAVED] = "interleaved", > > > }; > > > diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h > > > index dc909fb977c7..a2078c5f3d21 100644 > > > --- a/include/linux/mtd/rawnand.h > > > +++ b/include/linux/mtd/rawnand.h > > > @@ -92,6 +92,22 @@ enum nand_ecc_mode { > > > NAND_ECC_ON_DIE, > > > }; > > > > > > +/** > > > + * enum nand_ecc_engine_type - NAND ECC engine type/provider > > > + * @NAND_ECC_ENGINE_INVALID: Invalid value > > > + * @NAND_ECC_ENGINE_NONE: No ECC correction > > > + * @NAND_ECC_ENGINE_SOFT: Software ECC correction > > > + * @NAND_ECC_ENGINE_CONTROLLER: Hardware controller ECC correction > > > + * @NAND_ECC_ENGINE_ON_DIE: On chip hardware ECC correction > > > + */ > > > +enum nand_ecc_engine_type { > > > + NAND_ECC_ENGINE_INVALID, > > > + NAND_ECC_ENGINE_NONE, > > > + NAND_ECC_ENGINE_SOFT, > > > + NAND_ECC_ENGINE_CONTROLLER, > > > + NAND_ECC_ENGINE_ON_DIE, > > > +}; > > > + > > > /** > > > * enum nand_ecc_placement - NAND ECC placement > > > * @NAND_ECC_PLACEMENT_FREE: The driver can decide where to put ECC bytes. > >