Hi Shimoda-san,
On Tue, Sep 7, 2021 at 2:02 AM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
> > From: Geert Uytterhoeven, Sent: Tuesday, September 7, 2021 12:34 AM
> > On Wed, Sep 1, 2021 at 12:27 PM Yoshihiro Shimoda
> > <yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
> > > Add support for r8a779a0 (R-Car V3U). The IPMMU hardware design
> > > of this SoC differs than others. So, add a new ipmmu_features for it.
> > >
> > > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> >
> > > --- a/drivers/iommu/ipmmu-vmsa.c
> > > +++ b/drivers/iommu/ipmmu-vmsa.c
> >
> > > @@ -922,6 +922,20 @@ static const struct ipmmu_features ipmmu_features_rcar_gen3 = {
> > > .utlb_offset_base = 0,
> > > };
> > >
> > > +static const struct ipmmu_features ipmmu_features_r8a779a0 = {
> > > + .use_ns_alias_offset = false,
> > > + .has_cache_leaf_nodes = true,
> > > + .number_of_contexts = 8,
> >
> > Shouldn't this be 16?
> > Or do you plan to add support for more than 8 contexts later, as that
> > would require increasing IPMMU_CTX_MAX, and updating ipmmu_ctx_reg()
> > to handle the second bank of 8 contexts?
>
> I would like to add support for more than 8 contexts later because
> I realized that ctx_offset_{base,stride} are not suitable for the second bank
> of 8 contexts...
Wouldn't something like below be sufficient?
static unsigned int ipmmu_ctx_reg(struct ipmmu_vmsa_device *mmu,
unsigned int context_id, unsigned int reg)
{
- return mmu->features->ctx_offset_base +
- context_id * mmu->features->ctx_offset_stride + reg;
+ unsigned int base = mmu->features->ctx_offset_base;
+
+ if (context_id > 7)
+ base += 0x800 - 8 * 0x1040;
+
+ return base + context_id * mmu->features->ctx_offset_stride + reg;
}
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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
