[PATCH 1/2] platform: generic: thead: separate T-Head PMU Errata

[Anup Patel]

On Sun, Apr 21, 2024 at 9:22 PM Yangyu Chen <cyy at cyyself.name> wrote:
>
> As Guo Ren said from the kernel mailing list [1], future T-Head CPUs,
> including the newer versions of T-Head C908, will feature standard
> Sscofpmf extension. For these CPUs, T-Head's implementation of PMU
> Overflow Interrupts may not needed anymore. In this case, we shouldn't
> apply T-Head PMU for all T-Head CPUs. Thus, this patch separated T-Head PMU
> errata.
>
> [1] https://lore.kernel.org/linux-riscv/Zh9sUUUT09LZb0MO@gmail.com/
>
> Signed-off-by: Yangyu Chen <cyy at cyyself.name>

LGTM.

Reviewed-by: Anup Patel <anup at brainfault.org>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup

> ---
>  platform/generic/include/thead/c9xx_errata.h | 1 +
>  platform/generic/thead/thead-generic.c       | 8 ++++++--
>  2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/platform/generic/include/thead/c9xx_errata.h b/platform/generic/include/thead/c9xx_errata.h
> index bf97938..40c1587 100644
> --- a/platform/generic/include/thead/c9xx_errata.h
> +++ b/platform/generic/include/thead/c9xx_errata.h
> @@ -7,6 +7,7 @@
>   * stale entrie avoid incorrect memory access.
>   */
>  #define THEAD_QUIRK_ERRATA_TLB_FLUSH           BIT(0)
> +#define THEAD_QUIRK_ERRATA_THEAD_PMU           BIT(1)
>
>  void thead_register_tlb_flush_trap_handler(void);
>
> diff --git a/platform/generic/thead/thead-generic.c b/platform/generic/thead/thead-generic.c
> index 72f4aaa..da55e05 100644
> --- a/platform/generic/thead/thead-generic.c
> +++ b/platform/generic/thead/thead-generic.c
> @@ -33,12 +33,16 @@ static int thead_generic_early_init(bool cold_boot,
>  static int thead_generic_extensions_init(const struct fdt_match *match,
>                                          struct sbi_hart_features *hfeatures)
>  {
> -       thead_c9xx_register_pmu_device();
> +       struct thead_generic_quirks *quirks = (void *)match->data;
> +
> +       if (quirks->errata & THEAD_QUIRK_ERRATA_THEAD_PMU)
> +               thead_c9xx_register_pmu_device();
> +
>         return 0;
>  }
>
>  static struct thead_generic_quirks thead_th1520_quirks = {
> -       .errata = THEAD_QUIRK_ERRATA_TLB_FLUSH,
> +       .errata = THEAD_QUIRK_ERRATA_TLB_FLUSH | THEAD_QUIRK_ERRATA_THEAD_PMU,
>  };
>
>  static const struct fdt_match thead_generic_match[] = {
> --
> 2.43.0
>
>
> --
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