RE: [PATCH 3/3] iommu/ipmmu-vmsa: Add utlb_offset_base

[Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>]

Hi Geert-san,

> From: Geert Uytterhoeven, Sent: Friday, October 11, 2019 9:32 PM
> 
> Hi Shimoda-san,
> 
> On Wed, Oct 9, 2019 at 10:27 AM Yoshihiro Shimoda
> <yoshihiro.shimoda.uh@renesas.com> wrote:
> > Since we will have changed memory mapping of the IPMMU in the future,
> > this patch adds a utlb_offset_base into struct ipmmu_features
> > for IMUCTR and IMUASID registers.
> > No behavior change.
> >
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> 
> Thanks for your patch!
> 
> > --- a/drivers/iommu/ipmmu-vmsa.c
> > +++ b/drivers/iommu/ipmmu-vmsa.c
> > @@ -52,6 +52,7 @@ struct ipmmu_features {
> >         bool cache_snoop;
> >         u32 ctx_offset_base;
> >         u32 ctx_offset_stride;
> > +       u32 utlb_offset_base;
> >  };
> >
> >  struct ipmmu_vmsa_device {
> > @@ -285,6 +286,11 @@ static void ipmmu_ctx_write_all(struct ipmmu_vmsa_domain *domain,
> >         ipmmu_ctx_write_root(domain, reg, data);
> >  }
> >
> > +static u32 ipmmu_utlb_reg(struct ipmmu_vmsa_device *mmu, unsigned int reg)
> > +{
> > +       return mmu->features->utlb_offset_base + reg;
> > +}
> > +
> >  /* -----------------------------------------------------------------------------
> >   * TLB and microTLB Management
> >   */
> > @@ -330,9 +336,9 @@ static void ipmmu_utlb_enable(struct ipmmu_vmsa_domain *domain,
> >          */
> >
> >         /* TODO: What should we set the ASID to ? */
> > -       ipmmu_write(mmu, IMUASID(utlb), 0);
> > +       ipmmu_write(mmu, ipmmu_utlb_reg(mmu, IMUASID(utlb)), 0);
> >         /* TODO: Do we need to flush the microTLB ? */
> > -       ipmmu_write(mmu, IMUCTR(utlb),
> > +       ipmmu_write(mmu, ipmmu_utlb_reg(mmu, IMUCTR(utlb)),
> >                     IMUCTR_TTSEL_MMU(domain->context_id) | IMUCTR_FLUSH |
> >                     IMUCTR_MMUEN);
> 
> Like in [PATCH 2/3], I think providing two helpers would make this more
> readable:
> 
>     ipmmu_imuasid_write(mmu, utlb, 0);
>     ipmmu_imuctr_write(mmu, utlb, data);

I agree. I'll fix it.

Best regards,
Yoshihiro Shimoda

> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds