Hi Geert-san,
> From: Geert Uytterhoeven, Sent: Friday, October 11, 2019 9:29 PM
>
> Hi Shimoda-san,
>
> On Wed, Oct 9, 2019 at 10:27 AM Yoshihiro Shimoda
> <[email protected]> wrote:
> > Since we will have changed memory mapping of the IPMMU in the future,
> > this patch uses ipmmu_features values instead of a macro to
> > calculate context registers offset. No behavior change.
> >
> > Signed-off-by: Yoshihiro Shimoda <[email protected]>
>
> Thanks for your patch!
>
> > --- a/drivers/iommu/ipmmu-vmsa.c
> > +++ b/drivers/iommu/ipmmu-vmsa.c
> > @@ -50,6 +50,8 @@ struct ipmmu_features {
> > bool twobit_imttbcr_sl0;
> > bool reserved_context;
> > bool cache_snoop;
> > + u32 ctx_offset_base;
> > + u32 ctx_offset_stride;
> > };
> >
> > struct ipmmu_vmsa_device {
> > @@ -99,8 +101,6 @@ static struct ipmmu_vmsa_device *to_ipmmu(struct device
> > *dev)
> >
> > #define IM_NS_ALIAS_OFFSET 0x800
> >
> > -#define IM_CTX_SIZE 0x40
> > -
> > #define IMCTR 0x0000
> > #define IMCTR_TRE (1 << 17)
> > #define IMCTR_AFE (1 << 16)
> > @@ -253,18 +253,25 @@ static void ipmmu_write(struct ipmmu_vmsa_device
> > *mmu, unsigned int offset,
> > iowrite32(data, mmu->base + offset);
> > }
> >
> > +static u32 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;
> > +}
> > +
> > static u32 ipmmu_ctx_read_root(struct ipmmu_vmsa_domain *domain,
> > unsigned int reg)
> > {
> > return ipmmu_read(domain->mmu->root,
> > - domain->context_id * IM_CTX_SIZE + reg);
> > + ipmmu_ctx_reg(domain->mmu, domain->context_id,
> > reg));
>
> For consistency:
>
> ipmmu_ctx_reg(domain->mmu->root, ...)
>
> but in practice the features for domain->mmu and domain->mmu->root are
> identical anyway.
>
> > }
> >
> > static void ipmmu_ctx_write_root(struct ipmmu_vmsa_domain *domain,
> > unsigned int reg, u32 data)
> > {
> > ipmmu_write(domain->mmu->root,
> > - domain->context_id * IM_CTX_SIZE + reg, data);
> > + ipmmu_ctx_reg(domain->mmu, domain->context_id, reg),
> > data);
>
> Likewise:
>
> ipmmu_ctx_reg(domain->mmu->root, ...)?
Thank you for the comments! Yes, we can use domain->mmu->root to ipmmu_ctx_reg()
because ipmmu_ctx_reg() only use mmu->features.
> I find these ipmmu_{read,write}() a bit hard too read, with passing the
> mmu to both ipmmu_{read,write}() and ipmmu_ctx_reg().
I completely agree.
> What do you think about providing two helpers ipmmu_ctx_{read,write}(),
> so all users can just use e.g.
>
> ipmmu_ctx_write(mmu, context_id, reg, data);
>
> instead of
>
> ipmmu_write(mmu, ipmmu_ctx_reg(mmu, context_id, reg), data);
>
> ?
I think so. I'll fix it. Perhaps, I'll make a patch which changes
the function name at first.
Best regards,
Yoshihiro Shimoda
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> [email protected]
>
> 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
