[PATCH v2 1/2] powerpc: Introduce POWER10_DD1 feature

[Jordan Niethe]

On Thu, Oct 22, 2020 at 2:40 PM Ravi Bangoria
<ravi.bangoria at linux.ibm.com> wrote:
>
> POWER10_DD1 feature flag will be needed while adding
> conditional code that applies only for Power10 DD1.
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria at linux.ibm.com>
> ---
>  arch/powerpc/include/asm/cputable.h | 8 ++++++--
>  arch/powerpc/kernel/dt_cpu_ftrs.c   | 3 +++
>  arch/powerpc/kernel/prom.c          | 9 +++++++++
>  3 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
> index 93bc70d4c9a1..d486f56c0d33 100644
> --- a/arch/powerpc/include/asm/cputable.h
> +++ b/arch/powerpc/include/asm/cputable.h
> @@ -216,6 +216,7 @@ static inline void cpu_feature_keys_init(void) { }
>  #define CPU_FTR_P9_RADIX_PREFETCH_BUG  LONG_ASM_CONST(0x0002000000000000)
>  #define CPU_FTR_ARCH_31                        LONG_ASM_CONST(0x0004000000000000)
>  #define CPU_FTR_DAWR1                  LONG_ASM_CONST(0x0008000000000000)
> +#define CPU_FTR_POWER10_DD1            LONG_ASM_CONST(0x0010000000000000)
>
>  #ifndef __ASSEMBLY__
>
> @@ -479,6 +480,7 @@ static inline void cpu_feature_keys_init(void) { }
>             CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
>             CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | CPU_FTR_ARCH_31 | \
>             CPU_FTR_DAWR | CPU_FTR_DAWR1)
> +#define CPU_FTRS_POWER10_DD1   (CPU_FTRS_POWER10 | CPU_FTR_POWER10_DD1)
>  #define CPU_FTRS_CELL  (CPU_FTR_LWSYNC | \
>             CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
>             CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \
> @@ -497,14 +499,16 @@ static inline void cpu_feature_keys_init(void) { }
>  #define CPU_FTRS_POSSIBLE      \
>             (CPU_FTRS_POWER7 | CPU_FTRS_POWER8E | CPU_FTRS_POWER8 | \
>              CPU_FTR_ALTIVEC_COMP | CPU_FTR_VSX_COMP | CPU_FTRS_POWER9 | \
> -            CPU_FTRS_POWER9_DD2_1 | CPU_FTRS_POWER9_DD2_2 | CPU_FTRS_POWER10)
> +            CPU_FTRS_POWER9_DD2_1 | CPU_FTRS_POWER9_DD2_2 | CPU_FTRS_POWER10 | \
> +            CPU_FTRS_POWER10_DD1)
>  #else
>  #define CPU_FTRS_POSSIBLE      \
>             (CPU_FTRS_PPC970 | CPU_FTRS_POWER5 | \
>              CPU_FTRS_POWER6 | CPU_FTRS_POWER7 | CPU_FTRS_POWER8E | \
>              CPU_FTRS_POWER8 | CPU_FTRS_CELL | CPU_FTRS_PA6T | \
>              CPU_FTR_VSX_COMP | CPU_FTR_ALTIVEC_COMP | CPU_FTRS_POWER9 | \
> -            CPU_FTRS_POWER9_DD2_1 | CPU_FTRS_POWER9_DD2_2 | CPU_FTRS_POWER10)
> +            CPU_FTRS_POWER9_DD2_1 | CPU_FTRS_POWER9_DD2_2 | CPU_FTRS_POWER10 | \
> +            CPU_FTRS_POWER10_DD1)
>  #endif /* CONFIG_CPU_LITTLE_ENDIAN */
>  #endif
>  #else
> diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
> index 1098863e17ee..b2327f2967ff 100644
> --- a/arch/powerpc/kernel/dt_cpu_ftrs.c
> +++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
> @@ -811,6 +811,9 @@ static __init void cpufeatures_cpu_quirks(void)
>         }
>
>         update_tlbie_feature_flag(version);
> +
> +       if ((version & 0xffffffff) == 0x00800100)
> +               cur_cpu_spec->cpu_features |= CPU_FTR_POWER10_DD1;
>  }
>
>  static void __init cpufeatures_setup_finished(void)
> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
> index c1545f22c077..c778c81284f7 100644
> --- a/arch/powerpc/kernel/prom.c
> +++ b/arch/powerpc/kernel/prom.c
> @@ -305,6 +305,14 @@ static void __init check_cpu_feature_properties(unsigned long node)
>         }
>  }
>
> +static void __init fixup_cpu_features(void)
> +{
> +       unsigned long version = mfspr(SPRN_PVR);
> +
> +       if ((version & 0xffffffff) == 0x00800100)
> +               cur_cpu_spec->cpu_features |= CPU_FTR_POWER10_DD1;
> +}
> +
I am just wondering why this is needed here, but the same thing is not
done for, say, CPU_FTR_POWER9_DD2_1?
And should we get a /* Power10 DD 1 */ added to cpu_specs[]?

>  static int __init early_init_dt_scan_cpus(unsigned long node,
>                                           const char *uname, int depth,
>                                           void *data)
> @@ -378,6 +386,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
>
>                 check_cpu_feature_properties(node);
>                 check_cpu_pa_features(node);
> +               fixup_cpu_features();
>         }
>
>         identical_pvr_fixup(node);
> --
> 2.25.1
>