Re: [Intel-gfx] [PATCH 08/15] drm/i915/guc/slpc: Add methods to set min/max frequency

["Belgaumkar, Vinay" <vinay.belgaumkar@xxxxxxxxx>]

On 7/27/2021 8:24 AM, Michal Wajdeczko wrote:
> On 26.07.2021 21:07, Vinay Belgaumkar wrote:
> > Add param set h2g helpers to set the min and max frequencies
>
> s/h2g/H2G
>
> > for use by SLPC.
> >
> > v2: Address review comments (Michal W)
> > v3: Check for positive error code (Michal W)
> >
> > Signed-off-by: Sundaresan Sujaritha <sujaritha.sundaresan@xxxxxxxxx>
> > Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@xxxxxxxxx>
> > ---
> >   drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c | 89 ++++++++++++++++++++-
> >   drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h |  2 +
> >   2 files changed, 90 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> > index f5808d2acbca..63656640189c 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> > @@ -109,6 +109,21 @@ static u32 slpc_get_state(struct intel_guc_slpc *slpc)
> >   	return data->header.global_state;
> >   }
> >   
> > +static int guc_action_slpc_set_param(struct intel_guc *guc, u8 id, u32 value)
> > +{
> > +	u32 request[] = {
> > +		INTEL_GUC_ACTION_SLPC_REQUEST,
> > +		SLPC_EVENT(SLPC_EVENT_PARAMETER_SET, 2),
> > +		id,
> > +		value,
> > +	};
> > +	int ret;
> > +
> > +	ret = intel_guc_send(guc, request, ARRAY_SIZE(request));
> > +
> > +	return ret > 0 ? -EPROTO : ret;
> > +}
> > +
> >   static bool slpc_is_running(struct intel_guc_slpc *slpc)
> >   {
> >   	return (slpc_get_state(slpc) == SLPC_GLOBAL_STATE_RUNNING);
> > @@ -118,7 +133,7 @@ static int guc_action_slpc_query(struct intel_guc *guc, u32 offset)
> >   {
> >   	u32 request[] = {
> >   		INTEL_GUC_ACTION_SLPC_REQUEST,
> > - 		SLPC_EVENT(SLPC_EVENT_QUERY_TASK_STATE, 2),
> > +		SLPC_EVENT(SLPC_EVENT_QUERY_TASK_STATE, 2),
>
> this should be fixed in original patch
>
> >   		offset,
> >   		0,
> >   	};
> > @@ -146,6 +161,15 @@ static int slpc_query_task_state(struct intel_guc_slpc *slpc)
> >   	return ret;
> >   }
> >   
> > +static int slpc_set_param(struct intel_guc_slpc *slpc, u8 id, u32 value)
> > +{
> > +	struct intel_guc *guc = slpc_to_guc(slpc);
> > +
> > +	GEM_BUG_ON(id >= SLPC_MAX_PARAM);
> > +
> > +	return guc_action_slpc_set_param(guc, id, value);
> > +}
> > +
> >   static const char *slpc_global_state_to_string(enum slpc_global_state state)
> >   {
> >   	const char *str = NULL;
> > @@ -251,6 +275,69 @@ static u32 slpc_decode_max_freq(struct intel_guc_slpc *slpc)
> >   		GT_FREQUENCY_MULTIPLIER, GEN9_FREQ_SCALER);
> >   }
> >   
> > +/**
> > + * intel_guc_slpc_set_max_freq() - Set max frequency limit for SLPC.
> > + * @slpc: pointer to intel_guc_slpc.
> > + * @val: frequency (MHz)
> > + *
> > + * This function will invoke GuC SLPC action to update the max frequency
> > + * limit for unslice.
> > + *
> > + * Return: 0 on success, non-zero error code on failure.
> > + */
> > +int intel_guc_slpc_set_max_freq(struct intel_guc_slpc *slpc, u32 val)
> > +{
> > +	struct drm_i915_private *i915 = slpc_to_i915(slpc);
> > +	intel_wakeref_t wakeref;
> > +	int ret;
> > +
> > +	with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
> > +		ret = slpc_set_param(slpc,
> > +			       SLPC_PARAM_GLOBAL_MAX_GT_UNSLICE_FREQ_MHZ,
> > +			       val);
> > +		if (ret) {
> > +			drm_err(&i915->drm,
> > +				"Set max frequency unslice returned (%pe)\n", ERR_PTR(ret));
>
> maybe generic error reporting could be moved to slpc_set_param() ?
>
> > +			/* Return standardized err code for sysfs */
> > +			ret = -EIO;
>
> at this point we don't know if this function is for sysfs only
> I would sanitize error in "store" hook if really needed
>
> ssize_t slpc_max_freq_store(... const char *buf, size_t count)
> {
> 	...
> 	err = intel_guc_slpc_set_max_freq(slpc, val);
> 	return err ? -EIO : count;

that's the problem, sysfs wrapper will need to check for -EIO and 
-EINVAL, we want the ability to return either.

Thanks,
Vinay.
> }
>
> > +		}
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +/**
> > + * intel_guc_slpc_set_min_freq() - Set min frequency limit for SLPC.
> > + * @slpc: pointer to intel_guc_slpc.
> > + * @val: frequency (MHz)
> > + *
> > + * This function will invoke GuC SLPC action to update the min unslice
> > + * frequency.
> > + *
> > + * Return: 0 on success, non-zero error code on failure.
> > + */
> > +int intel_guc_slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 val)
> > +{
> > +	int ret;
> > +	struct intel_guc *guc = slpc_to_guc(slpc);
> > +	struct drm_i915_private *i915 = guc_to_gt(guc)->i915;
> > +	intel_wakeref_t wakeref;
> > +
> > +	with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
> > +		ret = slpc_set_param(slpc,
> > +			       SLPC_PARAM_GLOBAL_MIN_GT_UNSLICE_FREQ_MHZ,
> > +			       val);
> > +		if (ret) {
> > +			drm_err(&i915->drm,
> > +				"Set min frequency for unslice returned (%pe)\n", ERR_PTR(ret));
> > +			/* Return standardized err code for sysfs */
> > +			ret = -EIO;
> > +		}
> > +	}
>
> same here
>
> Michal
>
> > +
> > +	return ret;
> > +}
> > +
> >   /*
> >    * intel_guc_slpc_enable() - Start SLPC
> >    * @slpc: pointer to intel_guc_slpc.
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> > index c3b0ad7f0f93..e594510497ec 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> > @@ -29,5 +29,7 @@ void intel_guc_slpc_init_early(struct intel_guc_slpc *slpc);
> >   int intel_guc_slpc_init(struct intel_guc_slpc *slpc);
> >   int intel_guc_slpc_enable(struct intel_guc_slpc *slpc);
> >   void intel_guc_slpc_fini(struct intel_guc_slpc *slpc);
> > +int intel_guc_slpc_set_max_freq(struct intel_guc_slpc *slpc, u32 val);
> > +int intel_guc_slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 val);
> >   
> >   #endif