Re: [PATCH v6 7/8] drm/i915/pxp: On MTL, KCR enabling doesn't wait on tee component

["Ceraolo Spurio, Daniele" <daniele.ceraolospurio@xxxxxxxxx>]

On 2/27/2023 6:21 PM, Alan Previn wrote:
> On legacy platforms, KCR HW enabling is done at the time the mei
> component interface is bound. It's also disabled during unbind.
> However, for MTL onwards, we don't depend on a tee component
> to start sending GSC-CS firmware messages.
>
> Thus, immediately enable (or disable) KCR HW on PXP's init,
> fini and resume.
>
> Signed-off-by: Alan Previn <alan.previn.teres.alexis@xxxxxxxxx>
> ---
>   drivers/gpu/drm/i915/pxp/intel_pxp.c    | 19 +++++++++++++++----
>   drivers/gpu/drm/i915/pxp/intel_pxp_pm.c |  3 ++-
>   2 files changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.c b/drivers/gpu/drm/i915/pxp/intel_pxp.c
> index 61041277be24..e2f2cc5f6a6e 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp.c
> @@ -119,6 +119,7 @@ static void destroy_vcs_context(struct intel_pxp *pxp)
>   static void pxp_init_full(struct intel_pxp *pxp)
>   {
>   	struct intel_gt *gt = pxp->ctrl_gt;
> +	intel_wakeref_t wakeref;
>   	int ret;
>   
>   	/*
> @@ -140,10 +141,15 @@ static void pxp_init_full(struct intel_pxp *pxp)
>   	if (ret)
>   		return;
>   
> -	if (HAS_ENGINE(pxp->ctrl_gt, GSC0))
> +	if (HAS_ENGINE(pxp->ctrl_gt, GSC0)) {
>   		ret = intel_pxp_gsccs_init(pxp);
> -	else
> +		if (!ret) {
> +			with_intel_runtime_pm(&pxp->ctrl_gt->i915->runtime_pm, wakeref)
> +				intel_pxp_init_hw(pxp);

personal preference: I'd move this (and the matching call in fini) 
inside intel_pxp_gsccs_init/fini. That way we can see this as more 
back-end specific: the gsccs initialize everything immediately, while 
the tee back-end follows a 2-step approach with the component.
Not a blocker since it is a personal preference, so with or without the 
change:

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>

Daniele

> +		}
> +	} else {
>   		ret = intel_pxp_tee_component_init(pxp);
> +	}
>   	if (ret)
>   		goto out_context;
>   
> @@ -239,15 +245,20 @@ int intel_pxp_init(struct drm_i915_private *i915)
>   
>   void intel_pxp_fini(struct drm_i915_private *i915)
>   {
> +	intel_wakeref_t wakeref;
> +
>   	if (!i915->pxp)
>   		return;
>   
>   	i915->pxp->arb_is_valid = false;
>   
> -	if (HAS_ENGINE(i915->pxp->ctrl_gt, GSC0))
> +	if (HAS_ENGINE(i915->pxp->ctrl_gt, GSC0)) {
> +		with_intel_runtime_pm(&i915->pxp->ctrl_gt->i915->runtime_pm, wakeref)
> +			intel_pxp_fini_hw(i915->pxp);
>   		intel_pxp_gsccs_fini(i915->pxp);
> -	else
> +	} else {
>   		intel_pxp_tee_component_fini(i915->pxp);
> +	}
>   
>   	destroy_vcs_context(i915->pxp);
>   
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_pm.c b/drivers/gpu/drm/i915/pxp/intel_pxp_pm.c
> index 4f836b317424..1a04067f61fc 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_pm.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_pm.c
> @@ -43,8 +43,9 @@ void intel_pxp_resume_complete(struct intel_pxp *pxp)
>   	 * The PXP component gets automatically unbound when we go into S3 and
>   	 * re-bound after we come out, so in that scenario we can defer the
>   	 * hw init to the bind call.
> +	 * NOTE: GSC-CS backend doesn't rely on components.
>   	 */
> -	if (!pxp->pxp_component)
> +	if (!HAS_ENGINE(pxp->ctrl_gt, GSC0) && !pxp->pxp_component)
>   		return;
>   
>   	intel_pxp_init_hw(pxp);