Re: [PATCH kernel v2] powerpc/ioda: Use ibm, supported-tce-sizes for IOMMU page size mask

[Michael Ellerman]

Alexey Kardashevskiy <a...@ozlabs.ru> writes:

> At the moment we assume that IODA2 and newer PHBs can always do 4K/64K/16M
> IOMMU pages, however this is not the case for POWER9 and now skiboot
> advertises the supported sizes via the device so we use that instead
> of hard coding the mask.
>
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> ---
> Changes:
> v2:
> * added quirk for POWER8 to advertise 16M if skiboot has not provided info
> ---
>  arch/powerpc/platforms/powernv/pci-ioda.c | 26 +++++++++++++++++++++++++-
>  1 file changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c 
> b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 3f9c69d..891b4b6 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -2910,6 +2910,30 @@ static void pnv_pci_ioda2_table_free_pages(struct 
> iommu_table *tbl)
>                       tbl->it_indirect_levels);
>  }
>  
> +static unsigned long pnv_ioda_parse_tce_sizes(struct pnv_phb *phb)
> +{
> +     struct pci_controller *hose = phb->hose;
> +     struct device_node *dn = hose->dn;
> +     int i, len = 0;
> +     const __be32 *r;
> +     unsigned long mask = 0;
> +
> +     r = of_get_property(dn, "ibm,supported-tce-sizes", &len);
> +     if (!r || !len) {
> +             mask = SZ_4K | SZ_64K;
> +             /* Add 16M for POWER8 by default */
> +             if (cpu_has_feature(CPU_FTR_ARCH_207S) &&
> +                             !cpu_has_feature(CPU_FTR_ARCH_300))
> +                     mask |= SZ_16M;
> +             return mask;
> +     }
> +
> +     for (i = 0; i < len / sizeof(*r); ++i)
> +             mask |= 1ULL << be32_to_cpu(r[i]);
> +
> +     return mask;
> +}

Can we use the modern device tree accessors?

eg:


static unsigned long pnv_ioda_parse_tce_sizes(struct pnv_phb *phb)
{
        struct pci_controller *hose = phb->hose;
        struct device_node *dn = hose->dn;
        unsigned long mask = 0;
        int i, rc, count;
        u32 val;

        count = of_property_count_u32_elems(dn, "ibm,supported-tce-sizes");
        if (count <= 0) {
                mask = SZ_4K | SZ_64K;
                /* Add 16M for POWER8 by default */
                if (cpu_has_feature(CPU_FTR_ARCH_207S) &&
                                !cpu_has_feature(CPU_FTR_ARCH_300))
                        mask |= SZ_16M;
                return mask;
        }

        for (i = 0; i < count; i++) {
                rc = of_property_read_u32_index(dn, "ibm,supported-tce-sizes",
                                                i, &val);
                if (rc == 0)
                        mask |= 1ULL << val;
        }

        return mask;
}

cheers