linux-kernel - Re: [PATCH v2 3/5] iommu/mediatek: Remove the power status checking in tlb flush all

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Message-ID: <10ca4eae-2959-a697-6818-308e04f88e14@collabora.com>
Date:   Mon, 10 Jan 2022 12:43:46 +0100
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Dafna Hirschfeld <dafna.hirschfeld@...labora.com>,
        iommu@...ts.linux-foundation.org, Yong Wu <yong.wu@...iatek.com>,
        Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "moderated list:MEDIATEK IOMMU DRIVER" 
        <linux-mediatek@...ts.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-arm-kernel@...ts.infradead.org>,
        open list <linux-kernel@...r.kernel.org>, kernel@...labora.com,
        linux-media@...r.kernel.org, sebastian.reichel@...labora.com
Subject: Re: [PATCH v2 3/5] iommu/mediatek: Remove the power status checking
 in tlb flush all

Il 08/12/21 13:07, Dafna Hirschfeld ha scritto:
> From: Yong Wu <yong.wu@...iatek.com>
> 
> To simplify the code, Remove the power status checking in the
> tlb_flush_all, remove this:
>     if (pm_runtime_get_if_in_use(data->dev) <= 0)
> 	    continue;
> 
> The mtk_iommu_tlb_flush_all is called from
> a) isr
> b) tlb flush range fail case
> c) iommu_create_device_direct_mappings
> 
> In first two cases, the power and clock are always enabled.
> In the third case tlb flush is unnecessary because in a later patch
> in the series a full flush from the pm_runtime_resume callback is added.
> 
> In addition, writing the tlb control register when the iommu is not resumed
> is ok and the write is ignored.
> 
> Signed-off-by: Yong Wu <yong.wu@...iatek.com>
> [refactor commit log]
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@...labora.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>