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=-5.1 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,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 A1354C4363C for ; Sun, 4 Oct 2020 22:03:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 689C2206DD for ; Sun, 4 Oct 2020 22:03:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YGtddg2o" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726523AbgJDWDz (ORCPT ); Sun, 4 Oct 2020 18:03:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726398AbgJDWDz (ORCPT ); Sun, 4 Oct 2020 18:03:55 -0400 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C394C0613CE; Sun, 4 Oct 2020 15:03:54 -0700 (PDT) Received: by mail-pj1-x1043.google.com with SMTP id b17so4142969pji.1; Sun, 04 Oct 2020 15:03:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=hiTQzSF4WkdU76QTi9QZDEhHhUN1SUtqOZbzP+32RK4=; b=YGtddg2oP1zVqUfCFFhAO4LAsgstkdAA3IL24t43oNsEjqjCnBLxcRDpe3b4GkB7Fi qNS7GUN7e0UwYYngF/FYAHRRt9pEpyYgHhBTEXJw7dW4Fszet2kUTtBdOOjst2f1eQqu K7XHAlKWXJe28W7vaswHtMLoBI5fuOyTK9/TT/VXfA9MUOcNuGor+S4fK7KTerhChyC0 EEmoD8rnyMVoDE2sdy+Tk5LTuZN3I4oXlK/TRngSxw+8zU4ACUFj1NXaLTkQRSw0B0C3 p1ekNvDq/IAtbH7rRTGm7qBOkM1LZJxME3P5839WQfuSvdRBtxGFP7gALM94EdoMM5eR DsZg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=hiTQzSF4WkdU76QTi9QZDEhHhUN1SUtqOZbzP+32RK4=; b=Hv23CgaYdkC0rmNDmOoo59vKoMJcXdfonc/4fPghD8GL4pD4kg1/e5X7BYeiFt7NAT P1r26rBcCC92mzRqkq0a934s/70DYBqGpuVjfHNRkaQQiRDqYkdGGCTHvVB0BAdfceKe iMopnDJxjQHEKgEEutROk5asAeFIOVrdWXpC96g9G+CXzOpglmOBlBf/ccGGicIot1NN eSq8k3wl6g0XW54/2E4j2Tv/NzxSeVzsJI8ghIrysVbic/hCLt17J+n00rW0XgNJYE3d stYX2OoovxgiHOOpaYKyQKPUqDDyElT87YVsJvptSbnEkeAIEgTZIOGDpDJIBcvJ3LvT AoTg== X-Gm-Message-State: AOAM533Dw/Bg+0rJ5s+lOWCTXly3Cnb1kn/Jtub9GCTMQhyMXNN3MT8b 3cDNUKGfWBwJWvyaPzd1VxKjxjhtwDc= X-Google-Smtp-Source: ABdhPJymMfT4hxoF5YwtFJKrWgXA9ioeVfiQ8Bw5gURBdv8+OmuXnFjc/3+WMwpThxpJKagDsNeu6A== X-Received: by 2002:a17:90b:1741:: with SMTP id jf1mr13242190pjb.164.1601849033662; Sun, 04 Oct 2020 15:03:53 -0700 (PDT) Received: from Asurada-Nvidia (thunderhill.nvidia.com. [216.228.112.22]) by smtp.gmail.com with ESMTPSA id d128sm9942284pfc.8.2020.10.04.15.03.53 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sun, 04 Oct 2020 15:03:53 -0700 (PDT) Date: Sun, 4 Oct 2020 14:57:31 -0700 From: Nicolin Chen To: Dmitry Osipenko Cc: thierry.reding@gmail.com, joro@8bytes.org, vdumpa@nvidia.com, jonathanh@nvidia.com, linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 2/3] iommu/tegra-smmu: Rework tegra_smmu_probe_device() Message-ID: <20201004215731.GA21420@Asurada-Nvidia> References: <20201003065947.18671-1-nicoleotsuka@gmail.com> <20201003065947.18671-3-nicoleotsuka@gmail.com> <4a5a5b1c-080a-327a-1e2f-dc087948e1a1@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4a5a5b1c-080a-327a-1e2f-dc087948e1a1@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org On Sat, Oct 03, 2020 at 05:06:42PM +0300, Dmitry Osipenko wrote: > 03.10.2020 09:59, Nicolin Chen пишет: > > static int tegra_smmu_of_xlate(struct device *dev, > > struct of_phandle_args *args) > > { > > + struct platform_device *iommu_pdev = of_find_device_by_node(args->np); > > + struct tegra_mc *mc = platform_get_drvdata(iommu_pdev); > > u32 id = args->args[0]; > > > > + put_device(&iommu_pdev->dev); > > + > > + if (!mc || !mc->smmu) > > + return -EPROBE_DEFER; > > I'm not very excited by seeing code in the patches that can't be > explained by the patch authors and will appreciate if you could provide > a detailed explanation about why this NULL checking is needed because I > think it is unneeded, especially given that other IOMMU drivers don't > have such check. This function could be called from of_iommu_configure(), which is a part of other driver's probe(). So I think it's safer to have a check. Yet, given mc driver is added to the "arch_initcall" stage, you are probably right that there's no really need at this moment because all clients should be called after mc/smmu are inited. So I'll resend a v6, if that makes you happy. > I'm asking this question second time now, please don't ignore review > comments next time. I think I missed your reply or misunderstood it. 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[216.228.112.22]) by smtp.gmail.com with ESMTPSA id d128sm9942284pfc.8.2020.10.04.15.03.53 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sun, 04 Oct 2020 15:03:53 -0700 (PDT) Date: Sun, 4 Oct 2020 14:57:31 -0700 From: Nicolin Chen To: Dmitry Osipenko Subject: Re: [PATCH v5 2/3] iommu/tegra-smmu: Rework tegra_smmu_probe_device() Message-ID: <20201004215731.GA21420@Asurada-Nvidia> References: <20201003065947.18671-1-nicoleotsuka@gmail.com> <20201003065947.18671-3-nicoleotsuka@gmail.com> <4a5a5b1c-080a-327a-1e2f-dc087948e1a1@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <4a5a5b1c-080a-327a-1e2f-dc087948e1a1@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, jonathanh@nvidia.com, thierry.reding@gmail.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" T24gU2F0LCBPY3QgMDMsIDIwMjAgYXQgMDU6MDY6NDJQTSArMDMwMCwgRG1pdHJ5IE9zaXBlbmtv IHdyb3RlOgo+IDAzLjEwLjIwMjAgMDk6NTksIE5pY29saW4gQ2hlbiDQv9C40YjQtdGCOgo+ID4g IHN0YXRpYyBpbnQgdGVncmFfc21tdV9vZl94bGF0ZShzdHJ1Y3QgZGV2aWNlICpkZXYsCj4gPiAg CQkJICAgICAgIHN0cnVjdCBvZl9waGFuZGxlX2FyZ3MgKmFyZ3MpCj4gPiAgewo+ID4gKwlzdHJ1 Y3QgcGxhdGZvcm1fZGV2aWNlICppb21tdV9wZGV2ID0gb2ZfZmluZF9kZXZpY2VfYnlfbm9kZShh cmdzLT5ucCk7Cj4gPiArCXN0cnVjdCB0ZWdyYV9tYyAqbWMgPSBwbGF0Zm9ybV9nZXRfZHJ2ZGF0 YShpb21tdV9wZGV2KTsKPiA+ICAJdTMyIGlkID0gYXJncy0+YXJnc1swXTsKPiA+ICAKPiA+ICsJ cHV0X2RldmljZSgmaW9tbXVfcGRldi0+ZGV2KTsKPiA+ICsKPiA+ICsJaWYgKCFtYyB8fCAhbWMt PnNtbXUpCj4gPiArCQlyZXR1cm4gLUVQUk9CRV9ERUZFUjsKPiAKPiBJJ20gbm90IHZlcnkgZXhj aXRlZCBieSBzZWVpbmcgY29kZSBpbiB0aGUgcGF0Y2hlcyB0aGF0IGNhbid0IGJlCj4gZXhwbGFp bmVkIGJ5IHRoZSBwYXRjaCBhdXRob3JzIGFuZCB3aWxsIGFwcHJlY2lhdGUgaWYgeW91IGNvdWxk IHByb3ZpZGUKPiBhIGRldGFpbGVkIGV4cGxhbmF0aW9uIGFib3V0IHdoeSB0aGlzIE5VTEwgY2hl Y2tpbmcgaXMgbmVlZGVkIGJlY2F1c2UgSQo+IHRoaW5rIGl0IGlzIHVubmVlZGVkLCBlc3BlY2lh bGx5IGdpdmVuIHRoYXQgb3RoZXIgSU9NTVUgZHJpdmVycyBkb24ndAo+IGhhdmUgc3VjaCBjaGVj ay4KClRoaXMgZnVuY3Rpb24gY291bGQgYmUgY2FsbGVkIGZyb20gb2ZfaW9tbXVfY29uZmlndXJl KCksIHdoaWNoIGlzCmEgcGFydCBvZiBvdGhlciBkcml2ZXIncyBwcm9iZSgpLiBTbyBJIHRoaW5r IGl0J3Mgc2FmZXIgdG8gaGF2ZSBhCmNoZWNrLiBZZXQsIGdpdmVuIG1jIGRyaXZlciBpcyBhZGRl ZCB0byB0aGUgImFyY2hfaW5pdGNhbGwiIHN0YWdlLAp5b3UgYXJlIHByb2JhYmx5IHJpZ2h0IHRo YXQgdGhlcmUncyBubyByZWFsbHkgbmVlZCBhdCB0aGlzIG1vbWVudApiZWNhdXNlIGFsbCBjbGll bnRzIHNob3VsZCBiZSBjYWxsZWQgYWZ0ZXIgbWMvc21tdSBhcmUgaW5pdGVkLiBTbwpJJ2xsIHJl c2VuZCBhIHY2LCBpZiB0aGF0IG1ha2VzIHlvdSBoYXBweS4KCj4gSSdtIGFza2luZyB0aGlzIHF1 ZXN0aW9uIHNlY29uZCB0aW1lIG5vdywgcGxlYXNlIGRvbid0IGlnbm9yZSByZXZpZXcKPiBjb21t ZW50cyBuZXh0IHRpbWUuCgpJIHRoaW5rIEkgbWlzc2VkIHlvdXIgcmVwbHkgb3IgbWlzdW5kZXJz dG9vZCBpdC4KX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18K aW9tbXUgbWFpbGluZyBsaXN0CmlvbW11QGxpc3RzLmxpbnV4LWZvdW5kYXRpb24ub3JnCmh0dHBz Oi8vbGlzdHMubGludXhmb3VuZGF0aW9uLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2lvbW11