Re: [Intel-gfx] [PATCH v2 06/10] drm/i915/uc: Improve tracking of uC init status

["Michal Wajdeczko" <michal.wajdeczko@intel.com>]

On Tue, 04 Feb 2020 00:28:34 +0100, Daniele Ceraolo Spurio  
<daniele.ceraolospurio@intel.com> wrote:

> To be able to setup GuC submission functions during engine init we need
> to commit to using GuC as soon as possible.
> Currently, the only thing that can stop us from using the
> microcontrollers once we've fetched the blobs is a fundamental
> error (e.g. OOM); given that if we hit such an error we can't really
> fall-back to anything, we can "officialize" the FW fetching completion
> as the moment at which we're committing to using GuC.
>
> To better differentiate this case, the uses_guc check, which indicates
> that GuC is supported and was selected in modparam, is renamed to
> wants_guc and a new uses_guc is introduced to represent the case were
> we're committed to using the GuC. Note that uses_guc does still not imply
> that the blob is actually loaded on the HW (is_running is the check for
> that). Also, since we need to have attempted the fetch for the result
> of uses_guc to be meaningful, we need to make sure we've moved away
> from INTEL_UC_FIRMWARE_SELECTED.
>
> All the GuC changes have been mirrored on the HuC for coherency.
>
> v2: split fetch return changes and new macros to their own patches,
>     support HuC only if GuC is wanted, improve "used" state
>     description (Michal)
>
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Cc: John Harrison <John.C.Harrison@Intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>
> Reviewed-by: Fernando Pacheco <fernando.pacheco@intel.com> #v1
> ---
>  drivers/gpu/drm/i915/gt/uc/intel_guc.h    |  8 +++++++-
>  drivers/gpu/drm/i915/gt/uc/intel_huc.h    |  8 +++++++-
>  drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c |  2 +-
>  drivers/gpu/drm/i915/gt/uc/intel_uc.c     | 23 ++++++++++++----------
>  drivers/gpu/drm/i915/gt/uc/intel_uc.h     | 24 ++++++++++++++++++++++-
>  5 files changed, 51 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h  
> b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> index 7ca9e5159f05..f6b33745ae0b 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> @@ -143,11 +143,17 @@ static inline bool intel_guc_is_supported(struct  
> intel_guc *guc)
>  	return intel_uc_fw_is_supported(&guc->fw);
>  }
> -static inline bool intel_guc_is_enabled(struct intel_guc *guc)
> +static inline bool intel_guc_is_wanted(struct intel_guc *guc)
>  {
>  	return intel_uc_fw_is_enabled(&guc->fw);
>  }
> +static inline bool intel_guc_is_used(struct intel_guc *guc)
> +{
> +	GEM_BUG_ON(__intel_uc_fw_status(&guc->fw) ==  
> INTEL_UC_FIRMWARE_SELECTED);
> +	return intel_uc_fw_is_available(&guc->fw);
> +}
> +
>  static inline bool intel_guc_is_fw_running(struct intel_guc *guc)
>  {
>  	return intel_uc_fw_is_running(&guc->fw);
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc.h  
> b/drivers/gpu/drm/i915/gt/uc/intel_huc.h
> index 644c059fe01d..a40b9cfc6c22 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_huc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_huc.h
> @@ -41,11 +41,17 @@ static inline bool intel_huc_is_supported(struct  
> intel_huc *huc)
>  	return intel_uc_fw_is_supported(&huc->fw);
>  }
> -static inline bool intel_huc_is_enabled(struct intel_huc *huc)
> +static inline bool intel_huc_is_wanted(struct intel_huc *huc)
>  {
>  	return intel_uc_fw_is_enabled(&huc->fw);
>  }
> +static inline bool intel_huc_is_used(struct intel_huc *huc)
> +{
> +	GEM_BUG_ON(__intel_uc_fw_status(&huc->fw) ==  
> INTEL_UC_FIRMWARE_SELECTED);
> +	return intel_uc_fw_is_available(&huc->fw);
> +}
> +
>  static inline bool intel_huc_is_authenticated(struct intel_huc *huc)
>  {
>  	return intel_uc_fw_is_running(&huc->fw);
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c  
> b/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c
> index eee193bf2cc4..9cdf4cbe691c 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c
> @@ -20,7 +20,7 @@ void intel_huc_fw_init_early(struct intel_huc *huc)
>  	struct drm_i915_private *i915 = gt->i915;
> 	intel_uc_fw_init_early(&huc->fw, INTEL_UC_FW_TYPE_HUC,
> -			       intel_uc_uses_guc(uc),
> +			       intel_uc_wants_guc(uc),
>  			       INTEL_INFO(i915)->platform, INTEL_REVID(i915));
>  }
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c  
> b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> index affc4d6f9ead..654d7c0c757a 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> @@ -48,17 +48,17 @@ static void __confirm_options(struct intel_uc *uc)
>  	DRM_DEV_DEBUG_DRIVER(i915->drm.dev,
>  			     "enable_guc=%d (guc:%s submission:%s huc:%s)\n",
>  			     i915_modparams.enable_guc,
> -			     yesno(intel_uc_uses_guc(uc)),
> +			     yesno(intel_uc_wants_guc(uc)),
>  			     yesno(intel_uc_uses_guc_submission(uc)),
> -			     yesno(intel_uc_uses_huc(uc)));
> +			     yesno(intel_uc_wants_huc(uc)));
> 	if (i915_modparams.enable_guc == -1)
>  		return;
> 	if (i915_modparams.enable_guc == 0) {
> -		GEM_BUG_ON(intel_uc_uses_guc(uc));
> +		GEM_BUG_ON(intel_uc_wants_guc(uc));
>  		GEM_BUG_ON(intel_uc_uses_guc_submission(uc));
> -		GEM_BUG_ON(intel_uc_uses_huc(uc));
> +		GEM_BUG_ON(intel_uc_wants_huc(uc));
>  		return;
>  	}
> @@ -93,7 +93,7 @@ void intel_uc_init_early(struct intel_uc *uc)
> 	__confirm_options(uc);
> -	if (intel_uc_uses_guc(uc))
> +	if (intel_uc_wants_guc(uc))
>  		uc->ops = &uc_ops_on;
>  	else
>  		uc->ops = &uc_ops_off;
> @@ -257,13 +257,13 @@ static void __uc_fetch_firmwares(struct intel_uc  
> *uc)
>  {
>  	int err;
> -	GEM_BUG_ON(!intel_uc_uses_guc(uc));
> +	GEM_BUG_ON(!intel_uc_wants_guc(uc));
> 	err = intel_uc_fw_fetch(&uc->guc.fw);
>  	if (err)
>  		return;
> -	if (intel_uc_uses_huc(uc))
> +	if (intel_uc_wants_huc(uc))
>  		intel_uc_fw_fetch(&uc->huc.fw);
>  }
> @@ -279,7 +279,10 @@ static void __uc_init(struct intel_uc *uc)
>  	struct intel_huc *huc = &uc->huc;
>  	int ret;
> -	GEM_BUG_ON(!intel_uc_uses_guc(uc));
> +	GEM_BUG_ON(!intel_uc_wants_guc(uc));
> +
> +	if (!intel_uc_uses_guc(uc))
> +		return;
> 	/* XXX: GuC submission is unavailable for now */
>  	GEM_BUG_ON(intel_uc_supports_guc_submission(uc));
> @@ -322,7 +325,7 @@ static int uc_init_wopcm(struct intel_uc *uc)
>  	struct intel_uncore *uncore = gt->uncore;
>  	u32 base = intel_wopcm_guc_base(&gt->i915->wopcm);
>  	u32 size = intel_wopcm_guc_size(&gt->i915->wopcm);
> -	u32 huc_agent = intel_uc_uses_huc(uc) ? HUC_LOADING_AGENT_GUC : 0;
> +	u32 huc_agent = intel_uc_wants_huc(uc) ? HUC_LOADING_AGENT_GUC : 0;
>  	u32 mask;
>  	int err;
> @@ -402,7 +405,7 @@ static int __uc_init_hw(struct intel_uc *uc)
>  	int ret, attempts;
> 	GEM_BUG_ON(!intel_uc_supports_guc(uc));
> -	GEM_BUG_ON(!intel_uc_uses_guc(uc));
> +	GEM_BUG_ON(!intel_uc_wants_guc(uc));
> 	if (!intel_uc_fw_is_available(&guc->fw)) {
>  		ret = __uc_check_hw(uc) ||
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.h  
> b/drivers/gpu/drm/i915/gt/uc/intel_uc.h
> index 2ce993ceb60a..a41aaf353f88 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.h
> @@ -40,6 +40,27 @@ void intel_uc_runtime_suspend(struct intel_uc *uc);
>  int intel_uc_resume(struct intel_uc *uc);
>  int intel_uc_runtime_resume(struct intel_uc *uc);
> +/*
> + * We need to know as early as possible if we're going to use GuC or  
> not to
> + * take the correct setup paths. Additionally, once we've started  
> loading the
> + * GuC, it is unsafe to keep executing without it because some parts of  
> the HW,
> + * a subset of which is not cleaned on GT reset, will start expecting  
> the GuC FW
> + * to be running.
> + * To solve both these requirements, we commit to using the  
> microcontrollers if
> + * the relevant modparam is set and the blobs are found on the system.  
> At this
> + * stage, the only thing that can stop us from attempting to load the  
> blobs on
> + * the HW and use them is a fundamental issue (e.g. no memory for our
> + * structures); if we hit such a problem during driver load we're  
> broken even
> + * without GuC, so there is no point in trying to fall back.
> + *
> + * Given the above, we can be in one of 4 states, with the last one  
> implying
> + * we're committed to using the microcontroller:

nit: maybe we should document below state names in capitals as:
NOT_SUPPORTED, WANTED, IN_USE, ...

> + * - Not supported: not available in HW and/or firmware not defined.
> + * - Supported: available in HW and firmware defined.
> + * - Wanted: supported + enabled in modparam.

hmm, we are checking modparam during fw path selection, thus for me
there is no difference between SUPPORTED and WANTED, what I missed?

maybe we only need 3 states: NOT_SUPPORTED, WANTED, IN_USE.

> + * - In use: wanted + firmware found on the system and successfully  
> fetched.

In what state we will be after unsuccessful fetch ? still WANTED ?

> + */
> +
>  #define __uc_state_checker(x, state, required) \
>  static inline bool intel_uc_##state##_##x(struct intel_uc *uc) \
>  { \
> @@ -48,7 +69,8 @@ static inline bool intel_uc_##state##_##x(struct  
> intel_uc *uc) \
> #define uc_state_checkers(x) \
>  __uc_state_checker(x, supports, supported) \
> -__uc_state_checker(x, uses, enabled)
> +__uc_state_checker(x, wants, wanted) \
> +__uc_state_checker(x, uses, used)
> uc_state_checkers(guc);
>  uc_state_checkers(huc);
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