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=-8.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 B439CC4727E for ; Wed, 30 Sep 2020 16:06:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 69B912085B for ; Wed, 30 Sep 2020 16:06:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hFSzWCe1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731217AbgI3QGg (ORCPT ); Wed, 30 Sep 2020 12:06:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725799AbgI3QGa (ORCPT ); Wed, 30 Sep 2020 12:06:30 -0400 Received: from mail-lj1-x241.google.com (mail-lj1-x241.google.com [IPv6:2a00:1450:4864:20::241]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 78FA9C0613D0; Wed, 30 Sep 2020 09:06:30 -0700 (PDT) Received: by mail-lj1-x241.google.com with SMTP id c2so2054280ljj.12; Wed, 30 Sep 2020 09:06:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=4gz7hftu8wVBoM2xjJ8sNgXbJ69uPZrDK6qSgjMFO8I=; b=hFSzWCe1t/zf7VGo+FfqCZaoM/N2qY5YJVjPZrrragCSJ0GCR0wNhhr5u/xxo/tWTm NcgaqdHrXLERvv4almzK8/pq914nCnSiudPKBqkHHqSe5YmKUiPKLgOEH0UcpRMjCFZb ILpPyXIxobmb6CVlCLhWwB7qqDGBUvb6JmMV9CAfQ8latiICicceLFFrr/LSRbOFnBRz fOEFHGDu8XTrH+lUko8EgIv8aFEW/Me6673r1OR1PgGNtbQm4UguXXS6kdioPrTVUAdf v/OrZzPNbiiJ9bU22qt8XjdjfTed+eqe4P/3N/dqANE+FAYkrC93UjbEOKWIKopWSYXv DOnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=4gz7hftu8wVBoM2xjJ8sNgXbJ69uPZrDK6qSgjMFO8I=; b=EKh6H6KYcep+kEOpo+1Kno3IM3FG3SaF9GqwgpihhOkPE/L7DtvhSuFm9skgIULn+P C9vzbMT1943szrYF+f5F5DoH9zDkhH13hDSjbSm/9evKomY8FrjG6wUHZi4RiEkliDyS h55Ha9KfcouRGfpsPeVbrEP3DyHNHpxmg/boWX4AGme4wVq4NrfI+DsTSX6FnzbR97Tk HIKyfREupvsOYrEPNF3lQAppdabsGzyneVdowzEcl+Sc6w4V2TKVkyEDeyMaWNBWaVMS HAG910UEfGcdF9Eg0AeCYdhlygGJZEyFj+f6bMt03jGI2Cck1XVudY3bwzaUHkAXtrVQ NGQw== X-Gm-Message-State: AOAM532Ga+1phTTIqdmZC3nMIZGeNGerzi4wYElVnT5gss/TsbHm1fTv AkpHLNInlBse1vNeB3YmMloIyBoA6Pc= X-Google-Smtp-Source: ABdhPJySEV3K0WwibW3y87Twid/De/fw/N9Cf01bPjdaok5d/TQT/lVjDYUNqNrOHN6liUWW/eo3Qg== X-Received: by 2002:a2e:3511:: with SMTP id z17mr1000169ljz.58.1601481988722; Wed, 30 Sep 2020 09:06:28 -0700 (PDT) Received: from [192.168.2.145] (109-252-170-211.dynamic.spd-mgts.ru. [109.252.170.211]) by smtp.googlemail.com with ESMTPSA id l4sm236175lfg.296.2020.09.30.09.06.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 30 Sep 2020 09:06:28 -0700 (PDT) Subject: Re: [PATCH v3 1/3] memory: tegra: Add devm_tegra_get_memory_controller() To: Thierry Reding Cc: Nicolin Chen , joro@8bytes.org, krzk@kernel.org, vdumpa@nvidia.com, jonathanh@nvidia.com, linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20200930084258.25493-1-nicoleotsuka@gmail.com> <20200930084258.25493-2-nicoleotsuka@gmail.com> <20200930152320.GA3833404@ulmo> <20200930160355.GC3833404@ulmo> From: Dmitry Osipenko Message-ID: <839df5d6-513f-3d77-ba5f-a1afe5d0883a@gmail.com> Date: Wed, 30 Sep 2020 19:06:27 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200930160355.GC3833404@ulmo> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org 30.09.2020 19:03, Thierry Reding пишет: > On Wed, Sep 30, 2020 at 06:53:06PM +0300, Dmitry Osipenko wrote: >> 30.09.2020 18:23, Thierry Reding пишет: >>> On Wed, Sep 30, 2020 at 01:42:56AM -0700, Nicolin Chen wrote: >>>> From: Dmitry Osipenko >>>> >>>> Multiple Tegra drivers need to retrieve Memory Controller and hence there >>>> is quite some duplication of the retrieval code among the drivers. Let's >>>> add a new common helper for the retrieval of the MC. >>>> >>>> Signed-off-by: Dmitry Osipenko >>>> Signed-off-by: Nicolin Chen >>>> --- >>>> >>>> Changelog >>>> v2->v3: >>>> * Replaced with Dimtry's devm_tegra_get_memory_controller() >>>> v1->v2: >>>> * N/A >>>> >>>> drivers/memory/tegra/mc.c | 39 +++++++++++++++++++++++++++++++++++++++ >>>> include/soc/tegra/mc.h | 17 +++++++++++++++++ >>>> 2 files changed, 56 insertions(+) >>> >>> Let's not add this helper, please. If a device needs a reference to the >>> memory controller, it should have a phandle to the memory controller in >>> device tree so that it can be looked up explicitly. >>> >>> Adding this helper is officially sanctioning that it's okay not to have >>> that reference and that's a bad idea. >> >> And please explain why it's a bad idea, I don't see anything bad here at >> all. > > Well, you said yourself in a recent comment that we should avoid global > variables. devm_tegra_get_memory_controller() is nothing but a glorified > global variable. This is not a variable, but a common helper function which will remove the duplicated code and will help to avoid common mistakes like a missed put_device(). 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[109.252.170.211]) by smtp.googlemail.com with ESMTPSA id l4sm236175lfg.296.2020.09.30.09.06.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 30 Sep 2020 09:06:28 -0700 (PDT) Subject: Re: [PATCH v3 1/3] memory: tegra: Add devm_tegra_get_memory_controller() To: Thierry Reding References: <20200930084258.25493-1-nicoleotsuka@gmail.com> <20200930084258.25493-2-nicoleotsuka@gmail.com> <20200930152320.GA3833404@ulmo> <20200930160355.GC3833404@ulmo> From: Dmitry Osipenko Message-ID: <839df5d6-513f-3d77-ba5f-a1afe5d0883a@gmail.com> Date: Wed, 30 Sep 2020 19:06:27 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200930160355.GC3833404@ulmo> Content-Language: en-US Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, krzk@kernel.org, jonathanh@nvidia.com, linux-tegra@vger.kernel.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" MzAuMDkuMjAyMCAxOTowMywgVGhpZXJyeSBSZWRpbmcg0L/QuNGI0LXRgjoKPiBPbiBXZWQsIFNl cCAzMCwgMjAyMCBhdCAwNjo1MzowNlBNICswMzAwLCBEbWl0cnkgT3NpcGVua28gd3JvdGU6Cj4+ IDMwLjA5LjIwMjAgMTg6MjMsIFRoaWVycnkgUmVkaW5nINC/0LjRiNC10YI6Cj4+PiBPbiBXZWQs IFNlcCAzMCwgMjAyMCBhdCAwMTo0Mjo1NkFNIC0wNzAwLCBOaWNvbGluIENoZW4gd3JvdGU6Cj4+ Pj4gRnJvbTogRG1pdHJ5IE9zaXBlbmtvIDxkaWdldHhAZ21haWwuY29tPgo+Pj4+Cj4+Pj4gTXVs dGlwbGUgVGVncmEgZHJpdmVycyBuZWVkIHRvIHJldHJpZXZlIE1lbW9yeSBDb250cm9sbGVyIGFu ZCBoZW5jZSB0aGVyZQo+Pj4+IGlzIHF1aXRlIHNvbWUgZHVwbGljYXRpb24gb2YgdGhlIHJldHJp ZXZhbCBjb2RlIGFtb25nIHRoZSBkcml2ZXJzLiBMZXQncwo+Pj4+IGFkZCBhIG5ldyBjb21tb24g aGVscGVyIGZvciB0aGUgcmV0cmlldmFsIG9mIHRoZSBNQy4KPj4+Pgo+Pj4+IFNpZ25lZC1vZmYt Ynk6IERtaXRyeSBPc2lwZW5rbyA8ZGlnZXR4QGdtYWlsLmNvbT4KPj4+PiBTaWduZWQtb2ZmLWJ5 OiBOaWNvbGluIENoZW4gPG5pY29sZW90c3VrYUBnbWFpbC5jb20+Cj4+Pj4gLS0tCj4+Pj4KPj4+ PiBDaGFuZ2Vsb2cKPj4+PiB2Mi0+djM6Cj4+Pj4gICogUmVwbGFjZWQgd2l0aCBEaW10cnkncyBk ZXZtX3RlZ3JhX2dldF9tZW1vcnlfY29udHJvbGxlcigpCj4+Pj4gdjEtPnYyOgo+Pj4+ICAqIE4v QQo+Pj4+Cj4+Pj4gIGRyaXZlcnMvbWVtb3J5L3RlZ3JhL21jLmMgfCAzOSArKysrKysrKysrKysr KysrKysrKysrKysrKysrKysrKysrKysrKysKPj4+PiAgaW5jbHVkZS9zb2MvdGVncmEvbWMuaCAg ICB8IDE3ICsrKysrKysrKysrKysrKysrCj4+Pj4gIDIgZmlsZXMgY2hhbmdlZCwgNTYgaW5zZXJ0 aW9ucygrKQo+Pj4KPj4+IExldCdzIG5vdCBhZGQgdGhpcyBoZWxwZXIsIHBsZWFzZS4gSWYgYSBk ZXZpY2UgbmVlZHMgYSByZWZlcmVuY2UgdG8gdGhlCj4+PiBtZW1vcnkgY29udHJvbGxlciwgaXQg c2hvdWxkIGhhdmUgYSBwaGFuZGxlIHRvIHRoZSBtZW1vcnkgY29udHJvbGxlciBpbgo+Pj4gZGV2 aWNlIHRyZWUgc28gdGhhdCBpdCBjYW4gYmUgbG9va2VkIHVwIGV4cGxpY2l0bHkuCj4+Pgo+Pj4g QWRkaW5nIHRoaXMgaGVscGVyIGlzIG9mZmljaWFsbHkgc2FuY3Rpb25pbmcgdGhhdCBpdCdzIG9r YXkgbm90IHRvIGhhdmUKPj4+IHRoYXQgcmVmZXJlbmNlIGFuZCB0aGF0J3MgYSBiYWQgaWRlYS4K Pj4KPj4gQW5kIHBsZWFzZSBleHBsYWluIHdoeSBpdCdzIGEgYmFkIGlkZWEsIEkgZG9uJ3Qgc2Vl IGFueXRoaW5nIGJhZCBoZXJlIGF0Cj4+IGFsbC4KPiAKPiBXZWxsLCB5b3Ugc2FpZCB5b3Vyc2Vs ZiBpbiBhIHJlY2VudCBjb21tZW50IHRoYXQgd2Ugc2hvdWxkIGF2b2lkIGdsb2JhbAo+IHZhcmlh Ymxlcy4gZGV2bV90ZWdyYV9nZXRfbWVtb3J5X2NvbnRyb2xsZXIoKSBpcyBub3RoaW5nIGJ1dCBh IGdsb3JpZmllZAo+IGdsb2JhbCB2YXJpYWJsZS4KClRoaXMgaXMgbm90IGEgdmFyaWFibGUsIGJ1 dCBhIGNvbW1vbiBoZWxwZXIgZnVuY3Rpb24gd2hpY2ggd2lsbCByZW1vdmUKdGhlIGR1cGxpY2F0 ZWQgY29kZSBhbmQgd2lsbCBoZWxwIHRvIGF2b2lkIGNvbW1vbiBtaXN0YWtlcyBsaWtlIGEgbWlz c2VkCnB1dF9kZXZpY2UoKS4KX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX18KaW9tbXUgbWFpbGluZyBsaXN0CmlvbW11QGxpc3RzLmxpbnV4LWZvdW5kYXRpb24u b3JnCmh0dHBzOi8vbGlzdHMubGludXhmb3VuZGF0aW9uLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2lv bW11