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From: Tomasz Figa <tfiga@google.com>
To: Yong Wu <yong.wu@mediatek.com>
Cc: youlin.pei@mediatek.com, devicetree@vger.kernel.org,
	"Nicolas Boichat" <drinkcat@chromium.org>,
	srv_heupstream <srv_heupstream@mediatek.com>,
	"Joerg Roedel" <joro@8bytes.org>,
	"Will Deacon" <will.deacon@arm.com>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Evan Green" <evgreen@chromium.org>,
	"list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
	Joerg Roedel <joro@8bytes.org>,
	" <iommu@lists.linux-foundation.org>,
	"Rob Herring" <robh+dt@kernel.org>,
	"moderated list:ARM/Mediatek SoC support"
	<linux-mediatek@lists.infradead.org>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"Yingjoe Chen (陳英洲)" <yingjoe.chen@mediatek.com>,
	anan.sun@mediatek.com, "Robin Murphy" <robin.murphy@arm.com>,
	"Matthias Kaehlcke" <mka@chromium.org>,
	"list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
	Joerg Roedel <joro@8bytes.org>,
	" <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v7 14/21] iommu/mediatek: Add mmu1 support
Date: Tue, 18 Jun 2019 23:05:39 +0900
Message-ID: <CAAFQd5B8MiMA_OCUJ5HRmC5SA2772HF-rBGK0aZcKoWscOzOog@mail.gmail.com> (raw)
In-Reply-To: <1560859743.8082.23.camel@mhfsdcap03>

On Tue, Jun 18, 2019 at 9:09 PM Yong Wu <yong.wu@mediatek.com> wrote:
>
> On Tue, 2019-06-18 at 15:19 +0900, Tomasz Figa wrote:
> > On Mon, Jun 10, 2019 at 9:21 PM Yong Wu <yong.wu@mediatek.com> wrote:
> > >
> > > Normally the M4U HW connect EMI with smi. the diagram is like below:
> > >               EMI
> > >                |
> > >               M4U
> > >                |
> > >             smi-common
> > >                |
> > >        -----------------
> > >        |    |    |     |    ...
> > >     larb0 larb1  larb2 larb3
> > >
> > > Actually there are 2 mmu cells in the M4U HW, like this diagram:
> > >
> > >               EMI
> > >            ---------
> > >             |     |
> > >            mmu0  mmu1     <- M4U
> > >             |     |
> > >            ---------
> > >                |
> > >             smi-common
> > >                |
> > >        -----------------
> > >        |    |    |     |    ...
> > >     larb0 larb1  larb2 larb3
> > >
> > > This patch add support for mmu1. In order to get better performance,
> > > we could adjust some larbs go to mmu1 while the others still go to
> > > mmu0. This is controlled by a SMI COMMON register SMI_BUS_SEL(0x220).
> > >
> > > mt2712, mt8173 and mt8183 M4U HW all have 2 mmu cells. the default
> > > value of that register is 0 which means all the larbs go to mmu0
> > > defaultly.
> > >
> > > This is a preparing patch for adjusting SMI_BUS_SEL for mt8183.
> > >
> > > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > > Reviewed-by: Evan Green <evgreen@chromium.org>
> > > ---
> > >  drivers/iommu/mtk_iommu.c | 46 +++++++++++++++++++++++++++++-----------------
> > >  1 file changed, 29 insertions(+), 17 deletions(-)
> > >
> > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > > index 3a14301..ec4ce74 100644
> > > --- a/drivers/iommu/mtk_iommu.c
> > > +++ b/drivers/iommu/mtk_iommu.c
> > > @@ -72,26 +72,32 @@
> > >  #define F_INT_CLR_BIT                          BIT(12)
> > >
> > >  #define REG_MMU_INT_MAIN_CONTROL               0x124
> > > -#define F_INT_TRANSLATION_FAULT                        BIT(0)
> > > -#define F_INT_MAIN_MULTI_HIT_FAULT             BIT(1)
> > > -#define F_INT_INVALID_PA_FAULT                 BIT(2)
> > > -#define F_INT_ENTRY_REPLACEMENT_FAULT          BIT(3)
> > > -#define F_INT_TLB_MISS_FAULT                   BIT(4)
> > > -#define F_INT_MISS_TRANSACTION_FIFO_FAULT      BIT(5)
> > > -#define F_INT_PRETETCH_TRANSATION_FIFO_FAULT   BIT(6)
> > > +                                               /* mmu0 | mmu1 */
> > > +#define F_INT_TRANSLATION_FAULT                        (BIT(0) | BIT(7))
> > > +#define F_INT_MAIN_MULTI_HIT_FAULT             (BIT(1) | BIT(8))
> > > +#define F_INT_INVALID_PA_FAULT                 (BIT(2) | BIT(9))
> > > +#define F_INT_ENTRY_REPLACEMENT_FAULT          (BIT(3) | BIT(10))
> > > +#define F_INT_TLB_MISS_FAULT                   (BIT(4) | BIT(11))
> > > +#define F_INT_MISS_TRANSACTION_FIFO_FAULT      (BIT(5) | BIT(12))
> > > +#define F_INT_PRETETCH_TRANSATION_FIFO_FAULT   (BIT(6) | BIT(13))
> >
> > If there are two IOMMUs, shouldn't we have two driver instances handle
> > them, instead of making the driver combine them two internally?
>
> Actually it means only one IOMMU(M4U) HW here. Each a M4U HW has two
> small iommu cells which have independent MTLB. As the diagram above, M4U
> contain mmu0 and mmu1.
>
> MT8173 and MT8183 have only one M4U HW while MT2712 have 2 M4U HWs(two
> driver instances).
>
> >
> > And, what is even more important from security point of view actually,
> > have two separate page tables (aka IOMMU groups) for them?
>
> Each a IOMMU(M4U) have its own pagetable, thus, mt8183 have only one
> pagetable while mt2712 have two.

I see, thanks for clarifying.

Best regards,
Tomasz

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  reply index

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-10 12:17 [PATCH v7 00/21] MT8183 IOMMU SUPPORT Yong Wu
2019-06-10 12:17 ` [PATCH v7 01/21] dt-bindings: mediatek: Add binding for mt8183 IOMMU and SMI Yong Wu
2019-06-10 12:17 ` [PATCH v7 02/21] iommu/mediatek: Use a struct as the platform data Yong Wu
2019-06-10 12:17 ` [PATCH v7 03/21] memory: mtk-smi: Use a general config_port interface Yong Wu
2019-06-10 12:17 ` [PATCH v7 04/21] memory: mtk-smi: Use a struct for the platform data for smi-common Yong Wu
2019-06-10 12:17 ` [PATCH v7 05/21] iommu/io-pgtable-arm-v7s: Add paddr_to_iopte and iopte_to_paddr helpers Yong Wu
2019-06-10 12:17 ` [PATCH v7 06/21] iommu/io-pgtable-arm-v7s: Extend MediaTek 4GB Mode Yong Wu
2019-06-10 12:17 ` [PATCH v7 07/21] iommu/mediatek: Add bclk can be supported optionally Yong Wu
2019-06-15 19:18   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 08/21] iommu/mediatek: Add larb-id remapped support Yong Wu
2019-06-17  9:25   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 09/21] iommu/mediatek: Refine protect memory definition Yong Wu
2019-06-17  9:59   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 10/21] iommu/mediatek: Move reset_axi into plat_data Yong Wu
2019-06-17 10:19   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 11/21] iommu/mediatek: Move vld_pa_rng " Yong Wu
2019-06-17 10:27   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 12/21] memory: mtk-smi: Add gals support Yong Wu
2019-06-17 15:43   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 13/21] iommu/mediatek: Add mt8183 IOMMU support Yong Wu
2019-06-17 15:51   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 14/21] iommu/mediatek: Add mmu1 support Yong Wu
2019-06-17 15:58   ` Matthias Brugger
2019-06-18  6:19   ` Tomasz Figa
2019-06-18 12:09     ` Yong Wu
2019-06-18 14:05       ` Tomasz Figa [this message]
2019-06-10 12:17 ` [PATCH v7 15/21] memory: mtk-smi: Invoke pm runtime_callback to enable clocks Yong Wu
2019-06-17 16:13   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 16/21] memory: mtk-smi: Add bus_sel for mt8183 Yong Wu
2019-06-13  8:20   ` Pi-Hsun Shih
2019-06-17 16:28     ` Matthias Brugger
2019-06-17 16:23   ` Matthias Brugger
2019-06-18 12:10     ` Yong Wu
2019-06-18 21:07       ` Matthias Brugger
     [not found]   ` <CANdKZ0d873PJ2u=Hn_aUJBu3dDiNyueVwBv94-VXHGLJBvAbGg@mail.gmail.com>
2019-06-20  9:35     ` Matthias Brugger
2019-06-20 11:38       ` Matthias Brugger
2019-06-21  3:57         ` Pi-Hsun Shih
2019-06-10 12:17 ` [PATCH v7 17/21] memory: mtk-smi: Get rid of need_larbid Yong Wu
2019-06-18 13:45   ` Matthias Brugger
2019-06-20 13:59     ` Yong Wu
2019-06-10 12:17 ` [PATCH v7 18/21] iommu/mediatek: Fix VLD_PA_RNG register backup when suspend Yong Wu
2019-06-17 16:30   ` Matthias Brugger
2019-06-10 12:17 ` [PATCH v7 19/21] iommu/mediatek: Rename enable_4GB to dram_is_4gb Yong Wu
2019-06-18 16:06   ` Matthias Brugger
2019-06-20 13:59     ` Yong Wu
2019-06-21 10:10       ` Matthias Brugger
2019-06-22  2:42         ` Yong Wu
2019-06-10 12:17 ` [PATCH v7 20/21] iommu/mediatek: Fix iova_to_phys PA start for 4GB mode Yong Wu
2019-06-18 16:35   ` Matthias Brugger
2019-06-20 14:00     ` Yong Wu
2019-06-10 12:18 ` [PATCH v7 21/21] iommu/mediatek: Switch to SPDX license identifier Yong Wu
2019-06-17 16:33   ` Matthias Brugger

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