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 2DF6EC433F5 for ; Mon, 18 Oct 2021 07:13:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 12CA6610A3 for ; Mon, 18 Oct 2021 07:13:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230114AbhJRHPp (ORCPT ); Mon, 18 Oct 2021 03:15:45 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:58568 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230006AbhJRHPi (ORCPT ); Mon, 18 Oct 2021 03:15:38 -0400 Received: from [IPv6:2a02:810a:880:f54:88bb:da86:4533:43d6] (unknown [IPv6:2a02:810a:880:f54:88bb:da86:4533:43d6]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: dafna) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id BE80A1F42642; Mon, 18 Oct 2021 08:13:25 +0100 (BST) Subject: Re: [PATCH v8 04/12] iommu/mediatek: Add device_link between the consumer and the larb devices To: Yong Wu , Matthias Brugger , Joerg Roedel , Rob Herring , Krzysztof Kozlowski , David Airlie , Mauro Carvalho Chehab Cc: Evan Green , Robin Murphy , Tomasz Figa , Will Deacon , linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, youlin.pei@mediatek.com, Matthias Kaehlcke , anan.sun@mediatek.com, yi.kuo@mediatek.com, acourbot@chromium.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, Daniel Vetter , Chun-Kuang Hu , Philipp Zabel , Tiffany Lin , Hsin-Yi Wang , Eizan Miyamoto , anthony.huang@mediatek.com, Frank Wunderlich References: <20210929013719.25120-1-yong.wu@mediatek.com> <20210929013719.25120-5-yong.wu@mediatek.com> From: Dafna Hirschfeld Message-ID: Date: Mon, 18 Oct 2021 09:13:22 +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: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16.10.21 04:23, Yong Wu wrote: > On Mon, 2021-10-11 at 14:36 +0200, Dafna Hirschfeld wrote: >> >> On 29.09.21 03:37, Yong Wu wrote: >>> MediaTek IOMMU-SMI diagram is like below. all the consumer connect >>> with >>> smi-larb, then connect with smi-common. >>> >>> M4U >>> | >>> smi-common >>> | >>> ------------- >>> | | ... >>> | | >>> larb1 larb2 >>> | | >>> vdec venc >>> >>> When the consumer works, it should enable the smi-larb's power >>> which >>> also need enable the smi-common's power firstly. >>> >>> Thus, First of all, use the device link connect the consumer and >>> the >>> smi-larbs. then add device link between the smi-larb and smi- >>> common. >>> >>> This patch adds device_link between the consumer and the larbs. >>> >>> When device_link_add, I add the flag DL_FLAG_STATELESS to avoid >>> calling >>> pm_runtime_xx to keep the original status of clocks. It can avoid >>> two >>> issues: >>> 1) Display HW show fastlogo abnormally reported in [1]. At the >>> beggining, >>> all the clocks are enabled before entering kernel, but the clocks >>> for >>> display HW(always in larb0) will be gated after clk_enable and >>> clk_disable >>> called from device_link_add(->pm_runtime_resume) and rpm_idle. The >>> clock >>> operation happened before display driver probe. At that time, the >>> display >>> HW will be abnormal. >>> >>> 2) A deadlock issue reported in [2]. Use DL_FLAG_STATELESS to skip >>> pm_runtime_xx to avoid the deadlock. >>> >>> Corresponding, DL_FLAG_AUTOREMOVE_CONSUMER can't be added, then >>> device_link_removed should be added explicitly. >>> >>> [1] >>> https://lore.kernel.org/linux-mediatek/1564213888.22908.4.camel@mhfsdcap03/ >>> [2] https://lore.kernel.org/patchwork/patch/1086569/ >>> >>> Suggested-by: Tomasz Figa >>> Signed-off-by: Yong Wu >>> Tested-by: Frank Wunderlich # BPI- >>> R2/MT7623 >>> --- >>> drivers/iommu/mtk_iommu.c | 22 ++++++++++++++++++++++ >>> drivers/iommu/mtk_iommu_v1.c | 20 +++++++++++++++++++- >>> 2 files changed, 41 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c >>> index d5848f78a677..a2fa55899434 100644 >>> --- a/drivers/iommu/mtk_iommu.c >>> +++ b/drivers/iommu/mtk_iommu.c >>> @@ -560,22 +560,44 @@ static struct iommu_device >>> *mtk_iommu_probe_device(struct device *dev) >>> { >>> struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); >>> struct mtk_iommu_data *data; >>> + struct device_link *link; >>> + struct device *larbdev; >>> + unsigned int larbid; >>> >>> if (!fwspec || fwspec->ops != &mtk_iommu_ops) >>> return ERR_PTR(-ENODEV); /* Not a iommu client device >>> */ >>> >>> data = dev_iommu_priv_get(dev); >>> >>> + /* >>> + * Link the consumer device with the smi-larb device(supplier) >>> + * The device in each a larb is a independent HW. thus only >>> link >>> + * one larb here. >>> + */ >>> + larbid = MTK_M4U_TO_LARB(fwspec->ids[0]); >> >> so larbid is always the same for all the ids of a device? > > Yes. For me, each a dtsi node should represent a HW unit which can only > connect one larb. > >> If so maybe it worth testing it and return error if this is not the >> case. > > Thanks for the suggestion. This is very helpful. I did see someone put > the different larbs in one node. I will check this, and add return I am working on bugs found on media drivers, could you please point me to that wrong node? Will you send a fix to that node in the dtsi? Thanks, Dafna > EINVAL for this case. > >> >> Thanks, >> Dafna > >>>