Re: [PATCH v5 18/20] iommu/mediatek: Fix VLD_PA_RANGE register backup when suspend

[Yong Wu <yong.wu@mediatek.com>]

On Wed, 2019-01-02 at 14:54 +0800, Nicolas Boichat wrote:
> On Tue, Jan 1, 2019 at 11:59 AM Yong Wu <yong.wu@mediatek.com> wrote:
> >
> > The register VLD_PA_RNG(0x118) was forgot to backup while adding 4GB
> > mode support for mt2712. this patch add it.
> >
> > Fixes: 30e2fccf9512 ("iommu/mediatek: Enlarge the validate PA range
> > for 4GB mode")
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 ++
> >  drivers/iommu/mtk_iommu.h | 1 +
> >  2 files changed, 3 insertions(+)
> >
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 7fcef19..ddf1969 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -716,6 +716,7 @@ static int __maybe_unused mtk_iommu_suspend(struct device *dev)
> >         reg->int_control0 = readl_relaxed(base + REG_MMU_INT_CONTROL0);
> >         reg->int_main_control = readl_relaxed(base + REG_MMU_INT_MAIN_CONTROL);
> >         reg->ivrp_paddr = readl_relaxed(base + REG_MMU_IVRP_PADDR);
> > +       reg->vld_pa_range = readl_relaxed(base + REG_MMU_VLD_PA_RNG);
> 
> Don't we want to add:
> if (data->plat_data->vld_pa_rng)
> before this save/restore operation? Or it doesn't matter?

It doesn't matter. If some SoCs don't have it, the register doesn't
conflict with the others. Reading it will return 0, and writing 0 will
have no effect.

> 
> >         clk_disable_unprepare(data->bclk);
> >         return 0;
> >  }
> > @@ -740,6 +741,7 @@ static int __maybe_unused mtk_iommu_resume(struct device *dev)
> >         writel_relaxed(reg->int_control0, base + REG_MMU_INT_CONTROL0);
> >         writel_relaxed(reg->int_main_control, base + REG_MMU_INT_MAIN_CONTROL);
> >         writel_relaxed(reg->ivrp_paddr, base + REG_MMU_IVRP_PADDR);
> > +       writel_relaxed(reg->vld_pa_range, base + REG_MMU_VLD_PA_RNG);
> >         if (m4u_dom)
> >                 writel(m4u_dom->cfg.arm_v7s_cfg.ttbr[0] & MMU_PT_ADDR_MASK,
> >                        base + REG_MMU_PT_BASE_ADDR);
> > diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
> > index 0a7c463..c500bfd 100644
> > --- a/drivers/iommu/mtk_iommu.h
> > +++ b/drivers/iommu/mtk_iommu.h
> > @@ -33,6 +33,7 @@ struct mtk_iommu_suspend_reg {
> >         u32                             int_control0;
> >         u32                             int_main_control;
> >         u32                             ivrp_paddr;
> > +       u32                             vld_pa_range;
> 
> Well, please be consistent ,-) Either vld_pa_rng, or valid_pa_range ,-)

Thanks. I will use "vld_pa_rng", Keep same with the register name from
CODA.

> 
> >  };
> >
> >  enum mtk_iommu_plat {
> > --
> > 1.9.1
> >