[PATCH v2 02/13] lib: sbi: Detect AIA CSRs at boot-time

[Atish Patra]

On Wed, Feb 9, 2022 at 7:05 AM Anup Patel <apatel at ventanamicro.com> wrote:
>
> We extend HART feature detection to discover AIA CSRs at boot-time.
>
> Signed-off-by: Anup Patel <anup.patel at wdc.com>
> Signed-off-by: Anup Patel <apatel at ventanamicro.com>
> ---
>  include/sbi/sbi_hart.h |  4 +++-
>  lib/sbi/sbi_hart.c     | 11 +++++++++++
>  2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
> index d2db9d6..a83b45b 100644
> --- a/include/sbi/sbi_hart.h
> +++ b/include/sbi/sbi_hart.h
> @@ -24,9 +24,11 @@ enum sbi_hart_features {
>         SBI_HART_HAS_SSCOFPMF = (1 << 3),
>         /** HART has timer csr implementation in hardware */
>         SBI_HART_HAS_TIME = (1 << 4),
> +       /** HART has AIA local interrupt CSRs */
> +       SBI_HART_HAS_AIA = (1 << 5),
>
>         /** Last index of Hart features*/
> -       SBI_HART_HAS_LAST_FEATURE = SBI_HART_HAS_TIME,
> +       SBI_HART_HAS_LAST_FEATURE = SBI_HART_HAS_AIA,
>  };
>
>  struct sbi_scratch;
> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> index 36908b1..e028540 100644
> --- a/lib/sbi/sbi_hart.c
> +++ b/lib/sbi/sbi_hart.c
> @@ -301,6 +301,9 @@ static inline char *sbi_hart_feature_id2string(unsigned long feature)
>         case SBI_HART_HAS_TIME:
>                 fstr = "time";
>                 break;
> +       case SBI_HART_HAS_AIA:
> +               fstr = "aia";
> +               break;
>         default:
>                 break;
>         }
> @@ -524,6 +527,14 @@ __mhpm_skip:
>         csr_read_allowed(CSR_TIME, (unsigned long)&trap);
>         if (!trap.cause)
>                 hfeatures->features |= SBI_HART_HAS_TIME;
> +
> +       /* Detect if hart has AIA local interrupt CSRs */
> +       csr_read_allowed(CSR_MTOPI, (unsigned long)&trap);
> +       if (trap.cause)
> +               goto __aia_skip;
> +       hfeatures->features |= SBI_HART_HAS_AIA;
> +__aia_skip:
> +       return;
>  }
>
>  int sbi_hart_reinit(struct sbi_scratch *scratch)
> --
> 2.25.1
>

Reviewed-by: Atish Patra <atishp at rivosinc.com>


-- 
Regards,
Atish