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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50841C433EF for ; Tue, 9 Nov 2021 12:21:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F67860E8F for ; Tue, 9 Nov 2021 12:21:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241979AbhKIMYe (ORCPT ); Tue, 9 Nov 2021 07:24:34 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:48284 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241497AbhKIMYd (ORCPT ); Tue, 9 Nov 2021 07:24:33 -0500 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: dafna) with ESMTPSA id F1CFE1F44D7E DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=collabora.com; s=mail; t=1636460505; bh=icmFwD1DiBfEau8eUnScXn4nA4/iWPq/nH6eQjEm6v8=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=E985wN/8METi/vHeXCu7xQ7uLE6fvI8c5u7OyY5q5m1WILO849kR3+AL3VTBXW+c2 stcVgAI/mhzmx4XX0wafjqBIh7cTH19y6mOTRN1n15zASFRNzWx6zm9Fbh1a+IpPwA 9hBmXkt5n8G9m4xZkKXunZRj42g0XoJQDON4U2kBNG2kjQtRCO86eBvcqjeKJLR7J1 cVqVZtwhYdqTOR25sSXIQ8cg8SF9wCZULE7Do3JLxRLSmz5LzSuG/ek21D5Sg8Ogz2 RWhc2IzyQCO+eINdUl/w9OeP0WsTuAjIFVWC8c33RXWqurSflpMgSxJpICG6cpW55z SuHtylGB+Geuw== Subject: Re: [PATCH v3 12/33] iommu/mediatek: Always tlb_flush_all when each PM resume To: Yong Wu , Joerg Roedel , Rob Herring , Matthias Brugger , Will Deacon , Robin Murphy Cc: Krzysztof Kozlowski , Tomasz Figa , linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, Hsin-Yi Wang , youlin.pei@mediatek.com, anan.sun@mediatek.com, chao.hao@mediatek.com, yen-chang.chen@mediatek.com, AngeloGioacchino Del Regno , Fabien Parent , sebastian.reichel@collabora.com, Collabora Kernel ML References: <20210923115840.17813-1-yong.wu@mediatek.com> <20210923115840.17813-13-yong.wu@mediatek.com> From: Dafna Hirschfeld Message-ID: Date: Tue, 9 Nov 2021 14:21:37 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20210923115840.17813-13-yong.wu@mediatek.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi This patch is needed in order to update the tlb when a device is powered on. Could you send this patch alone without the whole series so it get accepted easier? I can resend the patch on your behalf if you want. Thanks, Dafna On 23.09.21 14:58, Yong Wu wrote: > Prepare for 2 HWs that sharing pgtable in different power-domains. > > When there are 2 M4U HWs, it may has problem in the flush_range in which > we get the pm_status via the m4u dev, BUT that function don't reflect the > real power-domain status of the HW since there may be other HW also use > that power-domain. > > The function dma_alloc_attrs help allocate the iommu buffer which > need the corresponding power domain since tlb flush is needed when > preparing iova. BUT this function only is for allocating buffer, > we have no good reason to request the user always call pm_runtime_get > before calling dma_alloc_xxx. Therefore, we add a tlb_flush_all > in the pm_runtime_resume to make sure the tlb always is clean. > > Another solution is always call pm_runtime_get in the tlb_flush_range. > This will trigger pm runtime resume/backup so often when the iommu > power is not active at some time(means user don't call pm_runtime_get > before calling dma_alloc_xxx), This may cause the performance drop. > thus we don't use this. > > In other case, the iommu's power should always be active via device > link with smi. > > The previous SoC don't have PM except mt8192. the mt8192 IOMMU is display's > power-domain which nearly always is enabled. thus no need fix tags here. > Prepare for mt8195. > > Signed-off-by: Yong Wu > --- > drivers/iommu/mtk_iommu.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > index 44cf5547d084..e9e94944ed91 100644 > --- a/drivers/iommu/mtk_iommu.c > +++ b/drivers/iommu/mtk_iommu.c > @@ -984,6 +984,17 @@ static int __maybe_unused mtk_iommu_runtime_resume(struct device *dev) > return ret; > } > > + /* > + * Users may allocate dma buffer before they call pm_runtime_get, then > + * it will lack the necessary tlb flush. > + * > + * We have no good reason to request the users always call dma_alloc_xx > + * after pm_runtime_get_sync. > + * > + * Thus, Make sure the tlb always is clean after each PM resume. > + */ > + mtk_iommu_tlb_do_flush_all(data); > + > /* > * Uppon first resume, only enable the clk and return, since the values of the > * registers are not yet set. >