[PATCH v7 11/12] lib: sbi: Add system_resume callback for restoring the system

[Anup Patel]

On Mon, Oct 20, 2025 at 11:57 AM Nick Hu <nick.hu at sifive.com> wrote:
>
> The last core who performs the system suspend is responsible for
> restoring the system after waking up. Add the system_resume callback for
> restoring the system from suspend.
>
> Suggested-by: Anup Patel <anup at brainfault.org>
> Signed-off-by: Nick Hu <nick.hu at sifive.com>

LGTM.

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

Regards,
Anup

> ---
>  include/sbi/sbi_system.h |  7 +++++++
>  lib/sbi/sbi_hsm.c        |  5 ++++-
>  lib/sbi/sbi_system.c     | 17 +++++++++++++++++
>  3 files changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/include/sbi/sbi_system.h b/include/sbi/sbi_system.h
> index 0fdcc98cce5dac43583e68ffa8c98e79fd95dad4..f48a019a06b6957b5ab9cb4b9ef795a899a34ff9 100644
> --- a/include/sbi/sbi_system.h
> +++ b/include/sbi/sbi_system.h
> @@ -69,11 +69,18 @@ struct sbi_system_suspend_device {
>          *     return from system_suspend() may ignore this parameter.
>          */
>         int (*system_suspend)(u32 sleep_type, unsigned long mmode_resume_addr);
> +
> +       /**
> +        * Resume the system from system suspend
> +        */
> +       void (*system_resume)(void);
>  };
>
>  const struct sbi_system_suspend_device *sbi_system_suspend_get_device(void);
>  void sbi_system_suspend_set_device(struct sbi_system_suspend_device *dev);
>  void sbi_system_suspend_test_enable(void);
> +void sbi_system_resume(void);
> +bool sbi_system_is_suspended(void);
>  bool sbi_system_suspend_supported(u32 sleep_type);
>  int sbi_system_suspend(u32 sleep_type, ulong resume_addr, ulong opaque);
>
> diff --git a/lib/sbi/sbi_hsm.c b/lib/sbi/sbi_hsm.c
> index 0d97b43e0cd8f7b4fc97407ef01007485e3f5a24..0a355f9c2372075aaf303cba2aa5683993c4c079 100644
> --- a/lib/sbi/sbi_hsm.c
> +++ b/lib/sbi/sbi_hsm.c
> @@ -455,7 +455,10 @@ void sbi_hsm_hart_resume_start(struct sbi_scratch *scratch)
>                                          SBI_HSM_STATE_RESUME_PENDING))
>                 sbi_hart_hang();
>
> -       hsm_device_hart_resume();
> +       if (sbi_system_is_suspended())
> +               sbi_system_resume();
> +       else
> +               hsm_device_hart_resume();
>  }
>
>  void __noreturn sbi_hsm_hart_resume_finish(struct sbi_scratch *scratch,
> diff --git a/lib/sbi/sbi_system.c b/lib/sbi/sbi_system.c
> index cd0f4ba42bbe67e606bc821870716f7342eaf0d2..5500b05d22882bd43d84a1b715529cd8a26bee3f 100644
> --- a/lib/sbi/sbi_system.c
> +++ b/lib/sbi/sbi_system.c
> @@ -87,6 +87,7 @@ void __noreturn sbi_system_reset(u32 reset_type, u32 reset_reason)
>  }
>
>  static const struct sbi_system_suspend_device *suspend_dev = NULL;
> +static bool system_suspended;
>
>  const struct sbi_system_suspend_device *sbi_system_suspend_get_device(void)
>  {
> @@ -137,6 +138,19 @@ bool sbi_system_suspend_supported(u32 sleep_type)
>                suspend_dev->system_suspend_check(sleep_type) == 0;
>  }
>
> +bool sbi_system_is_suspended(void)
> +{
> +       return system_suspended;
> +}
> +
> +void sbi_system_resume(void)
> +{
> +       if (suspend_dev && suspend_dev->system_resume)
> +               suspend_dev->system_resume();
> +
> +       system_suspended = false;
> +}
> +
>  int sbi_system_suspend(u32 sleep_type, ulong resume_addr, ulong opaque)
>  {
>         struct sbi_domain *dom = sbi_domain_thishart_ptr();
> @@ -189,11 +203,14 @@ int sbi_system_suspend(u32 sleep_type, ulong resume_addr, ulong opaque)
>         __sbi_hsm_suspend_non_ret_save(scratch);
>
>         /* Suspend */
> +       system_suspended = true;
>         ret = suspend_dev->system_suspend(sleep_type, scratch->warmboot_addr);
>         if (ret != SBI_OK) {
>                 if (!sbi_hsm_hart_change_state(scratch, SBI_HSM_STATE_SUSPENDED,
>                                                SBI_HSM_STATE_STARTED))
>                         sbi_hart_hang();
> +
> +               system_suspended = false;
>                 return ret;
>         }
>
>
> --
> 2.34.1
>