[RFC PATCH 1/2] lib: sbi_hsm: Call a device hook during hart resume

[Anup Patel]

On Fri, May 6, 2022 at 12:27 PM Samuel Holland <samuel at sholland.org> wrote:
>
> Non-retentive suspend states may require platform-specific actions
> during resume. For example, firmware may need to save and restore the
> values of custom CSRs. Add a hook to support this.
>
> Signed-off-by: Samuel Holland <samuel at sholland.org>

Looks good to me.

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

Thanks,
Anup

> ---
>
>  include/sbi/sbi_hsm.h | 8 ++++++++
>  lib/sbi/sbi_hsm.c     | 8 ++++++++
>  2 files changed, 16 insertions(+)
>
> diff --git a/include/sbi/sbi_hsm.h b/include/sbi/sbi_hsm.h
> index c16e871..6da8cee 100644
> --- a/include/sbi/sbi_hsm.h
> +++ b/include/sbi/sbi_hsm.h
> @@ -37,6 +37,14 @@ struct sbi_hsm_device {
>          * specified resume address
>          */
>         int (*hart_suspend)(u32 suspend_type, ulong raddr);
> +
> +       /**
> +        * Perform platform-specific actions to resume from a suspended state.
> +        *
> +        * This includes restoring any platform state that was lost during
> +        * non-retentive suspend.
> +        */
> +       void (*hart_resume)(void);
>  };
>
>  struct sbi_domain;
> diff --git a/lib/sbi/sbi_hsm.c b/lib/sbi/sbi_hsm.c
> index c4d2c6d..a7b6a80 100644
> --- a/lib/sbi/sbi_hsm.c
> +++ b/lib/sbi/sbi_hsm.c
> @@ -178,6 +178,12 @@ static int hsm_device_hart_suspend(u32 suspend_type, ulong raddr)
>         return SBI_ENOTSUPP;
>  }
>
> +static void hsm_device_hart_resume(void)
> +{
> +       if (hsm_dev && hsm_dev->hart_resume)
> +               hsm_dev->hart_resume();
> +}
> +
>  int sbi_hsm_init(struct sbi_scratch *scratch, u32 hartid, bool cold_boot)
>  {
>         u32 i;
> @@ -384,6 +390,8 @@ void sbi_hsm_hart_resume_start(struct sbi_scratch *scratch)
>                            __func__, oldstate);
>                 sbi_hart_hang();
>         }
> +
> +       hsm_device_hart_resume();
>  }
>
>  void sbi_hsm_hart_resume_finish(struct sbi_scratch *scratch)
> --
> 2.35.1
>
>
> --
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