From: "yf.wang--- via iommu" <iommu@lists.linux-foundation.org>
To: <yong.wu@mediatek.com>
Cc: wsd_upstream@mediatek.com, will@kernel.org,
linux-kernel@vger.kernel.org, Libo.Kang@mediatek.com,
yf.wang@mediatek.com, iommu@lists.linux-foundation.org,
linux-mediatek@lists.infradead.org, ning.li@mediatek.com,
matthias.bgg@gmail.com, robin.murphy@arm.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v5 2/2] iommu/mediatek: Allow page table PA up to 35bit
Date: Wed, 25 May 2022 13:36:42 +0800 [thread overview]
Message-ID: <20220525053642.29653-1-yf.wang@mediatek.com> (raw)
In-Reply-To: <1625ec1f4cded0f825d93743d3d03fcf83cad5aa.camel@mediatek.com>
On Thu, 2022-05-19 at 14:58 +0800, Yong Wu wrote:
> On Mon, 2022-05-16 at 22:16 +0800, yf.wang@mediatek.com wrote:
> > From: Yunfei Wang <yf.wang@mediatek.com>
> >
> > Add the quirk IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT support, so that
> > allows
> > page table PA up to 35bit, not only in ZONE_DMA32.
>
> Comment why this is needed.
>
> e.g. For single normal zone.
>
Hi Yong,
There is no DMA32 zone in some mediatek smartphone chip for single normal zone.
The level 1 and level 2 pgtable are both allocated in ZONE_DMA32, and may have two possible problem:
1.The level 2 pgtable is allocated in ZONE_DMA32 with atomic flag, and it may fail if ZONE_DMA32 memory is used out.
2.Single memory feature will make ZONE_DMA32 empty, and cause level 1 and level 2 pgtable PA more than 32bit.
Solution:
Add the quirk IO_PGTABLE_QUIRK_ARM_MTK_TTBR_EXT support, so that level 1 and level 2 pgtable can support at most 35bit PA.
I will update the commit message in next version.
Thanks,
Yunfei.
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next prev parent reply other threads:[~2022-05-25 5:43 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220516141608.11709-1-yf.wang@mediatek.com>
2022-05-16 14:16 ` [PATCH v5 1/2] iommu/io-pgtable-arm-v7s: Add a quirk to allow pgtable PA up to 35bit yf.wang--- via iommu
2022-05-19 6:27 ` Miles Chen via iommu
2022-05-25 3:21 ` yf.wang--- via iommu
2022-05-16 14:16 ` [PATCH v5 2/2] iommu/mediatek: Allow page table " yf.wang--- via iommu
2022-05-19 6:58 ` Yong Wu via iommu
2022-05-25 5:36 ` yf.wang--- via iommu [this message]
2022-06-11 10:20 ` yf.wang--- via iommu
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