[PATCH] lib: sbi: Enable M-mode external interrupt only for AIA

[Anup Patel]

On Fri, Feb 18, 2022 at 10:27 PM Atish Patra <atishp at rivosinc.com> wrote:
>
> Some platforms may inject spurious M-mode external interrupt if
> the external interrupt bit is enabled in mie. We really don't
> need to enable M-mode external interrupts for platforms without
> AIA. This issue is observed in HiFive unmatched.
>
> Keep the M-mode external interrupt disabled for non-AIA platforms.
>
> Signed-off-by: Atish Patra <atishp at rivosinc.com>
> ---
>  lib/sbi/sbi_init.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
> index 6876eb2f0f22..76b7c5d953ec 100644
> --- a/lib/sbi/sbi_init.c
> +++ b/lib/sbi/sbi_init.c
> @@ -276,7 +276,12 @@ static void __noreturn init_coldboot(struct sbi_scratch *scratch, u32 hartid)
>                            __func__, rc);
>                 sbi_hart_hang();
>         }
> -       csr_set(CSR_MIE, MIP_MEIP);
> +       /**
> +        * HiFive unmatched platform generates spurious interrupt if external
> +        * interrupt is enabled in mie. Enable it only if AIA is present.
> +        */
> +       if (sbi_hart_has_feature(scratch, SBI_HART_HAS_AIA))

Actually, we have to check for AIA IMSIC and not just AIA.

Regards,
Anup

> +               csr_set(CSR_MIE, MIP_MEIP);
>
>         rc = sbi_ipi_init(scratch, TRUE);
>         if (rc) {
> @@ -377,7 +382,12 @@ static void init_warm_startup(struct sbi_scratch *scratch, u32 hartid)
>         rc = sbi_platform_irqchip_init(plat, FALSE);
>         if (rc)
>                 sbi_hart_hang();
> -       csr_set(CSR_MIE, MIP_MEIP);
> +       /**
> +        * HiFive unmatched platform generates spurious interrupt if external
> +        * interrupt is enabled in mie. Enable it only if AIA is present.
> +        */
> +       if (sbi_hart_has_feature(scratch, SBI_HART_HAS_AIA))
> +               csr_set(CSR_MIE, MIP_MEIP);
>
>         rc = sbi_ipi_init(scratch, FALSE);
>         if (rc)
> --
> 2.30.2
>
>
> --
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