[Skiboot] [PATCH V2 1/2] opal-prd: Add support for runtime OCC reset in ZZ

[Nicholas Piggin]

On Wed,  6 Dec 2017 19:47:01 +0530
Shilpasri G Bhat <shilpa.bhat at linux.vnet.ibm.com> wrote:

> This patch handles OCC_RESET runtime events in host opal-prd and also
> provides support for calling 'hostinterface->wakeup()' which is
> required for doing the reset operation.
> 
> Signed-off-by: Shilpasri G Bhat <shilpa.bhat at linux.vnet.ibm.com>
> ---
>  core/direct-controls.c       |  27 +++++++++++
>  core/hostservices.c          |  46 +++++++++++++++++-
>  external/opal-prd/opal-prd.c | 112 +++++++++++++++++++++++++++++++++++++++++++
>  external/opal-prd/thunk.S    |   2 +-
>  hw/occ.c                     |  51 +++++++++++++++++++-
>  hw/prd.c                     |  22 +++++++++
>  include/cpu.h                |   1 +
>  include/hostservices.h       |   2 +
>  include/opal-api.h           |  11 +++++
>  include/skiboot.h            |   1 +
>  10 files changed, 272 insertions(+), 3 deletions(-)
> 
> diff --git a/core/direct-controls.c b/core/direct-controls.c
> index ba3e4d1..39c9a75 100644
> --- a/core/direct-controls.c
> +++ b/core/direct-controls.c
> @@ -554,6 +554,33 @@ int dctl_core_is_gated(struct cpu_thread *t)
>  	return !!(val & P9_CORE_GATED);
>  }
>  
> +int dctl_clear_all_special_wakeup(void)
> +{
> +	struct proc_chip *chip;
> +	struct cpu_thread *c;
> +	int rc;
> +
> +	if (proc_gen != proc_gen_p9)
> +		return OPAL_UNSUPPORTED;
> +
> +	for_each_chip(chip)
> +		for_each_available_core_in_chip(c, chip->id) {
> +			lock(&c->dctl_lock);
> +			if (c->special_wakeup_count) {
> +				rc = p9_core_clear_special_wakeup(c);
> +				if (!rc) {
> +					c->special_wakeup_count = 0;
> +				} else {
> +					unlock(&c->dctl_lock);
> +					return rc;
> +				}
> +			}
> +			unlock(&c->dctl_lock);
> +		}
> +
> +	return OPAL_SUCCESS;
> +}

This seems wrong, because there may be other users of special wakeup
apart from host services.

What are the semantics expected for this? My guess is that it wants
to undo the effect of all previous calls to ->wakeup(). In that case
I think another counter is needed to count hservice wakeups.

Thanks,
Nick