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=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=no 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 A887AC433DF for ; Wed, 14 Oct 2020 12:59:49 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 27F8E20848 for ; Wed, 14 Oct 2020 12:59:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="c0ByUXFx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 27F8E20848 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=collabora.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:References:In-Reply-To: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=sBnDSq9jxCGBnD+dmyU8nkRjA9T7GfKBZJhnhAFO7AU=; b=c0ByUXFx3eKAO9oG9EErs6rE1 wV5nUwdQk2dznVxgDbU3kGN+eOShibeW6fMRSD2VYOy+yh2YuS/yuEg5zuhYTMG18Lic0DcDrRDFX +DSmgruUQ2/oFZDUU8ypFCx3YMGSmxbTqXfvW34aot0PeiF8ZdknjXhVKzFR+KTmci8n6tJCiUcEg eCHzhXnvFAxAPPgVfAmon9TWDXSaPV05Ik/n+yOoPtkCEnYS+mKfK4PLDChhGRRCab1BZH/sgwkeq 4evjqmXskvHqo7LZvegVnzPFm/L+JgN4V6KvJI8eSbnxZ6GP7kOmpK+7iFqyYcC7wZkZLZ0kuGo/R nykWj3XkA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kSgNY-0008TU-WC; Wed, 14 Oct 2020 12:59:41 +0000 Received: from bhuna.collabora.co.uk ([46.235.227.227]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kSgNW-0008SP-4f for linux-rockchip@lists.infradead.org; Wed, 14 Oct 2020 12:59:39 +0000 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: aratiu) with ESMTPSA id CC77C1F41295 From: Adrian Ratiu To: Mark Brown , Adrian Ratiu Subject: Re: [PATCH 07/18] regmap: mmio: add config option to allow relaxed MMIO accesses In-Reply-To: <20201014121249.GA4580@sirena.org.uk> References: <20201012205957.889185-1-adrian.ratiu@collabora.com> <20201012205957.889185-8-adrian.ratiu@collabora.com> <20201013102656.GA5425@sirena.org.uk> <87o8l581ql.fsf@collabora.com> <20201014121249.GA4580@sirena.org.uk> Date: Wed, 14 Oct 2020 16:00:38 +0300 Message-ID: <87lfg97yix.fsf@collabora.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201014_085938_283747_85480860 X-CRM114-Status: GOOD ( 26.39 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fruehberger Peter , kernel@collabora.com, Philipp Zabel , linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, kuhanh.murugasen.krishnan@intel.com, Daniel Vetter , Mauro Carvalho Chehab , Ezequiel Garcia , linux-media@vger.kernel.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org On Wed, 14 Oct 2020, Mark Brown wrote: > On Wed, Oct 14, 2020 at 02:51:14PM +0300, Adrian Ratiu wrote: >> On Tue, 13 Oct 2020, Mark Brown wrote: >> > On Mon, Oct 12, 2020 at 11:59:46PM +0300, Adrian Ratiu wrote: > >> > > - writeb(val, ctx->regs + reg); + if >> > > (ctx->relaxed_mmio) + writeb_relaxed(val, ctx->regs + reg); >> > > + else + writeb(val, ctx->regs + reg); > >> > There is no point in doing a conditional operation on every >> > I/O, it'd be better to register a different set of ops when >> > doing relaxed I/O. > >> Indeed I have considered adding new functions but went with >> this solution because it's easier for the users to only have to >> define a "relaxed" config then test the regmap ctx as above. > > It seems like you've taken this in a direction other than what > I was thinking of here - defining separate ops doesn't mean we > have to do anything which has any impact on the interface seen > by users. The regmap config is supplied at registration time, > it's just as available then as it is when doing I/O. Right. I got confused by the meaning of ops :) Sorry about that. > >> Thinking a bit more about it, yes, it makes more sense to have >> dedicated ops: this way users don't have to be explicit about >> adding membarriers and can combine relaxed and non-relaxed more >> easily, so it's also a better API trade-off in addition to >> avoiding the conditional. Thanks! > > I'm not sure what you're proposing here - it does seem useful to > be able to combine relaxed and non-relaxed I/O but that seems > like it'd break down the abstraction for regmap since tht's not > really a concept other buses are going to have? Unless we > provide an operation to switch by setting flags or somethin > possibly and integrate it with the cache perhaps. Could you be > a bit more specific about what you were thinking of here please? I was thinking about exposing a relaxed API like regmap_write_relaxed but now that I know what you meant by ops and also that it doesn't make sense for other busses / violates the abstraction, I realize that is a bad idea and I will continue improving this to avoid the conditional and send a separete patch. Thanks again! > >> Question: Do you want me to split this patch from the series and send it >> separately just for the regmap subsystem to be easier to review / apply? > > Sure. _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip