linux-kernel - Re: [PATCH v5 09/20] iommu/mediatek: Refine protect memory definition

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Date:   Wed, 2 Jan 2019 17:33:35 +0800
From:   Yong Wu <yong.wu@...iatek.com>
To:     Nicolas Boichat <drinkcat@...omium.org>,
        Matthias Brugger <matthias.bgg@...il.com>
CC:     Joerg Roedel <joro@...tes.org>,
        Robin Murphy <robin.murphy@....com>,
        "Rob Herring" <robh+dt@...nel.org>, Tomasz Figa <tfiga@...gle.com>,
        Will Deacon <will.deacon@....com>,
        <linux-mediatek@...ts.infradead.org>,
        <srv_heupstream@...iatek.com>, <devicetree@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        <iommu@...ts.linux-foundation.org>, Arnd Bergmann <arnd@...db.de>,
        Yingjoe Chen <yingjoe.chen@...iatek.com>,
        <youlin.pei@...iatek.com>
Subject: Re: [PATCH v5 09/20] iommu/mediatek: Refine protect memory
 definition

On Wed, 2019-01-02 at 14:23 +0800, Nicolas Boichat wrote:
> On Tue, Jan 1, 2019 at 11:58 AM Yong Wu <yong.wu@...iatek.com> wrote:
> >
> > The protect memory setting is a little different in the different SoCs.
> > In the register REG_MMU_CTRL_REG(0x110), the TF_PROT(translation fault
> > protect) shift bit is normally 4 while it shift 5 bits only in the
> > mt8173. This patch delete the complex MACRO and use a common if-else
> > instead.
> >
> > Also, use "F_MMU_TF_PROT_TO_PROGRAM_ADDR" instead of the hard code(2)
> > which means the M4U will output the dirty data to the programmed
> > address that we allocated dynamically when translation fault occurs.
> >
> > Signed-off-by: Yong Wu <yong.wu@...iatek.com>
> > ---
> > @Nicalos, I don't put it in the plat_data since only the previous mt8173
> > shift 5. As I know, the latest SoC always use the new setting like mt2712
> > and mt8183. Thus, I think it is unnecessary to put it in plat_data and
> > let all the latest SoC set it. Hence, I still keep "== mt8173" for this
> > like the reg REG_MMU_CTRL_REG.
> 
> Should be ok this way. But maybe one way to avoid hard-coding 4/5
> below is to have 2 macros:
> 
> #define F_MMU_TF_PROT_TO_PROGRAM_ADDR (2 << 4)
> #define F_MMU_TF_PROT_TO_PROGRAM_ADDR_MT8173 (2 << 5)
> 
> And still use the if below?

Thanks for your quick review.

OK for me.

I will wait Matthias's review for memory/ part. then send the next
version.

> 
> > ---
> >  drivers/iommu/mtk_iommu.c | 12 +++++-------
> >  1 file changed, 5 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index eca1536..35a1263 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -53,11 +53,7 @@
> >
> >  #define REG_MMU_CTRL_REG                       0x110
> >  #define F_MMU_PREFETCH_RT_REPLACE_MOD          BIT(4)
> > -#define F_MMU_TF_PROTECT_SEL_SHIFT(data) \
> > -       ((data)->plat_data->m4u_plat == M4U_MT2712 ? 4 : 5)
> > -/* It's named by F_MMU_TF_PROT_SEL in mt2712. */
> > -#define F_MMU_TF_PROTECT_SEL(prot, data) \
> > -       (((prot) & 0x3) << F_MMU_TF_PROTECT_SEL_SHIFT(data))
> > +#define F_MMU_TF_PROT_TO_PROGRAM_ADDR          2
> >
> >  #define REG_MMU_IVRP_PADDR                     0x114
> >
> > @@ -521,9 +517,11 @@ static int mtk_iommu_hw_init(const struct mtk_iommu_data *data)
> >                 return ret;
> >         }
> >
> > -       regval = F_MMU_TF_PROTECT_SEL(2, data);
> >         if (data->plat_data->m4u_plat == M4U_MT8173)
> > -               regval |= F_MMU_PREFETCH_RT_REPLACE_MOD;
> > +               regval = F_MMU_PREFETCH_RT_REPLACE_MOD |
> > +                         (F_MMU_TF_PROT_TO_PROGRAM_ADDR << 5);
> > +       else
> > +               regval = F_MMU_TF_PROT_TO_PROGRAM_ADDR << 4;
> >         writel_relaxed(regval, data->base + REG_MMU_CTRL_REG);
> >
> >         regval = F_L2_MULIT_HIT_EN |
> > --
> > 1.9.1
> >