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, URIBL_BLOCKED,USER_AGENT_SANE_1 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 B5EEAC4CECE for ; Mon, 14 Oct 2019 14:13:22 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (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 82D882083B for ; Mon, 14 Oct 2019 14:13:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82D882083B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id EE61A1489; Mon, 14 Oct 2019 14:13:21 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 4ABB9141F for ; Mon, 14 Oct 2019 14:04:48 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id E52095D3 for ; Mon, 14 Oct 2019 14:04:46 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 83EDF337; Mon, 14 Oct 2019 07:04:46 -0700 (PDT) Received: from [10.1.197.57] (e110467-lin.cambridge.arm.com [10.1.197.57]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 22A513F68E; Mon, 14 Oct 2019 07:04:43 -0700 (PDT) Subject: Re: [PATCH v3 6/7] iommu/mediatek: Use writel for TLB range invalidation To: Yong Wu , Matthias Brugger , Joerg Roedel , Will Deacon References: <1571035101-4213-1-git-send-email-yong.wu@mediatek.com> <1571035101-4213-7-git-send-email-yong.wu@mediatek.com> From: Robin Murphy Message-ID: Date: Mon, 14 Oct 2019 15:04:42 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <1571035101-4213-7-git-send-email-yong.wu@mediatek.com> Content-Language: en-GB Cc: youlin.pei@mediatek.com, anan.sun@mediatek.com, Nicolas Boichat , cui.zhang@mediatek.com, srv_heupstream@mediatek.com, chao.hao@mediatek.com, edison.hsieh@mediatek.com, linux-kernel@vger.kernel.org, Evan Green , Tomasz Figa , iommu@lists.linux-foundation.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On 14/10/2019 07:38, Yong Wu wrote: > Use writel for the register F_MMU_INV_RANGE which is for triggering the > HW work. We expect all the setting(iova_start/iova_end...) have already > been finished before F_MMU_INV_RANGE. For Arm CPUs, these registers should be mapped as Device memory, therefore the same-peripheral rule should implicitly enforce that the accesses are made in program order, hence you're unlikely to have seen a problem in reality. However, the logical reasoning for the change seems valid in general, so I'd argue that it's still worth making if only for the sake of good practice: Acked-by: Robin Murphy > Signed-off-by: Anan.Sun > Signed-off-by: Yong Wu > --- > drivers/iommu/mtk_iommu.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > index dbbacc3..d285457 100644 > --- a/drivers/iommu/mtk_iommu.c > +++ b/drivers/iommu/mtk_iommu.c > @@ -187,8 +187,7 @@ static void mtk_iommu_tlb_flush_range_sync(unsigned long iova, size_t size, > writel_relaxed(iova, data->base + REG_MMU_INVLD_START_A); > writel_relaxed(iova + size - 1, > data->base + REG_MMU_INVLD_END_A); > - writel_relaxed(F_MMU_INV_RANGE, > - data->base + REG_MMU_INVALIDATE); > + writel(F_MMU_INV_RANGE, data->base + REG_MMU_INVALIDATE); > > /* tlb sync */ > ret = readl_poll_timeout_atomic(data->base + REG_MMU_CPE_DONE, > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu