Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <1546314952-15990-1-git-send-email-yong.wu@mediatek.com> <1546314952-15990-20-git-send-email-yong.wu@mediatek.com>
In-Reply-To: <1546314952-15990-20-git-send-email-yong.wu@mediatek.com>
From:   Evan Green <evgreen@chromium.org>
Date:   Wed, 30 Jan 2019 11:12:51 -0800
Message-ID: <CAE=gft4g4HbDG7shtiqUP5vw9tiyRr4VEheMGM2uhEL_65yYmg@mail.gmail.com>
Subject: Re: [PATCH v5 19/20] iommu/mediatek: Add shutdown callback
To:     Yong Wu <yong.wu@mediatek.com>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Rob Herring <robh+dt@kernel.org>,
        Tomasz Figa <tfiga@google.com>,
        Will Deacon <will.deacon@arm.com>,
        linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        linux-arm-kernel@lists.infradead.org,
        iommu@lists.linux-foundation.org, Arnd Bergmann <arnd@arndb.de>,
        yingjoe.chen@mediatek.com, youlin.pei@mediatek.com,
        Nicolas Boichat <drinkcat@chromium.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Dec 31, 2018 at 8:00 PM Yong Wu <yong.wu@mediatek.com> wrote:
>
> In the reboot burning test, if some Multimedia HW has something wrong,
> It may keep send the invalid request to IOMMU. In order to avoid
> affect the reboot flow, we add the shutdown callback to disable
> M4U HW when shutdown.

Sounds unpleasant. Hopefully the reboot flow still continues properly
even in that case, since this shutdown code may not run during some
rougher resets.

Reviewed-by: Evan Green <evgreen@chromium.org>