[RFC PATCH 09/11] lib: sbi: Implement system suspend

[Anup Patel]

On Fri, Jan 6, 2023 at 4:52 PM Andrew Jones <ajones at ventanamicro.com> wrote:
>
> Fill the implementation of the system suspend ecall. A platform
> implementation of the suspend callbacks is still required for this
> to do anything.
>
> Signed-off-by: Andrew Jones <ajones at ventanamicro.com>

Looks good to me.

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

Regards,
Anup

> ---
>  lib/sbi/sbi_system.c | 57 +++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 56 insertions(+), 1 deletion(-)
>
> diff --git a/lib/sbi/sbi_system.c b/lib/sbi/sbi_system.c
> index 5c123a6c9d8d..c18562cdcfab 100644
> --- a/lib/sbi/sbi_system.c
> +++ b/lib/sbi/sbi_system.c
> @@ -116,5 +116,60 @@ bool sbi_system_suspend_supported(u32 sleep_type)
>
>  int sbi_system_suspend(u32 sleep_type, ulong resume_addr, ulong opaque)
>  {
> -       return 0;
> +       int ret = SBI_ENOTSUPP;
> +       const struct sbi_domain *dom = sbi_domain_thishart_ptr();
> +       struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
> +       void (*jump_warmboot)(void) = (void (*)(void))scratch->warmboot_addr;
> +       unsigned int hartid = current_hartid();
> +       unsigned long prev_mode;
> +       unsigned long i;
> +
> +       if (!dom || !dom->system_suspend_allowed)
> +               return SBI_EFAIL;
> +
> +       if (!suspend_dev || !suspend_dev->system_suspend)
> +               return SBI_EFAIL;
> +
> +       if (!sbi_system_suspend_supported(sleep_type))
> +               return SBI_ENOTSUPP;
> +
> +       prev_mode = (csr_read(CSR_MSTATUS) & MSTATUS_MPP) >> MSTATUS_MPP_SHIFT;
> +       if (prev_mode != PRV_S && prev_mode != PRV_U)
> +               return SBI_EFAIL;
> +
> +       sbi_hartmask_for_each_hart(i, &dom->assigned_harts) {
> +               if (i == hartid)
> +                       continue;
> +               if (__sbi_hsm_hart_get_state(i) != SBI_HSM_STATE_STOPPED)
> +                       return SBI_EFAIL;
> +       }
> +
> +       if (!sbi_domain_check_addr(dom, resume_addr, prev_mode,
> +                                  SBI_DOMAIN_EXECUTE))
> +               return SBI_EINVALID_ADDR;
> +
> +       if (!sbi_hsm_hart_change_state(scratch, SBI_HSM_STATE_STARTED,
> +                                      SBI_HSM_STATE_SUSPENDED))
> +               return SBI_EFAIL;
> +
> +       /* Prepare for resume */
> +       scratch->next_mode = prev_mode;
> +       scratch->next_addr = resume_addr;
> +       scratch->next_arg1 = opaque;
> +
> +       __sbi_hsm_suspend_non_ret_save(scratch);
> +
> +       /* Suspend */
> +       ret = suspend_dev->system_suspend(sleep_type);
> +       if (ret != SBI_OK) {
> +               if (!sbi_hsm_hart_change_state(scratch, SBI_HSM_STATE_SUSPENDED,
> +                                              SBI_HSM_STATE_STARTED))
> +                       sbi_hart_hang();
> +               return ret;
> +       }
> +
> +       /* Resume */
> +       jump_warmboot();
> +
> +       __builtin_unreachable();
>  }
> --
> 2.39.0
>
>
> --
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