Re: [PATCH 10/13] drm/i915/cnl: Unify dvfs level selection.

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Wed, Oct 04, 2017 at 01:20:57PM +0000, Mika Kahola wrote:
> On Tue, 2017-10-03 at 00:06 -0700, Rodrigo Vivi wrote:
> > When port clock is zero or undefined we base our
> > calculation on cdclk. So, same function can be used
> > for port clock == 0 now that we have the same default "2".
> > 
> > v2: s/get/new: When documenting "get" sounded ambiguous
> >     because we could be getting the current level at pcode.
> > 
> > Cc: Mika Kahola <mika.kahola@intel.com>
> > Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_cdclk.c    | 28 +++++++++++++----------
> > -----
> >  drivers/gpu/drm/i915/intel_dpll_mgr.c | 12 +-----------
> >  drivers/gpu/drm/i915/intel_drv.h      |  1 +
> >  3 files changed, 15 insertions(+), 26 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_cdclk.c
> > b/drivers/gpu/drm/i915/intel_cdclk.c
> > index 7e9c4444c844..c62d6e752fb7 100644
> > --- a/drivers/gpu/drm/i915/intel_cdclk.c
> > +++ b/drivers/gpu/drm/i915/intel_cdclk.c
> > @@ -1535,12 +1535,22 @@ void cnl_dvfs_post_change(struct
> > drm_i915_private *dev_priv, int level)
> >  	mutex_unlock(&dev_priv->rps.hw_lock);
> >  }
> >  
> > +int cnl_dvfs_new_level(int cdclk, int portclk)
> > +{
> > +	if (cdclk == 168000 && portclk <= 594000)
> > +		return 0;
> > +	else if (cdclk == 336000 && portclk <= 594000)
> > +		return 1;
> > +	else
> > +		return 2;
> > +}
> > +
> Maybe we could leave the function name as cnl_get_dvfs_level()?
> The original one is stripped down later in this patch.

Since I was exporting I decided to use the same standard as others
and move dvfs back a bit
so cnl_dvfs_get_level...
But also when I was documenting on the last patch I noticed
that "get level" is kind of ambiguous... which level? the current
or the new? the more natural is current, but this function also
get the new desired/needed.

But I'm open to other suggestions that fix the ambiguity.

>  
> >  static void cnl_set_cdclk(struct drm_i915_private *dev_priv,
> >  			  const struct intel_cdclk_state
> > *cdclk_state)
> >  {
> >  	int cdclk = cdclk_state->cdclk;
> >  	int vco = cdclk_state->vco;
> > -	u32 val, divider, pcu_ack;
> > +	u32 val, divider, level;
> >  
> >  	if (cnl_dvfs_pre_change(dev_priv))
> >  		return;
> > @@ -1561,19 +1571,6 @@ static void cnl_set_cdclk(struct
> > drm_i915_private *dev_priv,
> >  		break;
> >  	}
> >  
> > -	switch (cdclk) {
> > -	case 168000:
> > -		pcu_ack = 0;
> > -		break;
> > -	case 336000:
> > -		pcu_ack = 1;
> > -		break;
> > -	case 528000:
> > -	default:
> > -		pcu_ack = 2;
> > -		break;
> > -	}
> > -
> >  	if (dev_priv->cdclk.hw.vco != 0 &&
> >  	    dev_priv->cdclk.hw.vco != vco)
> >  		cnl_cdclk_pll_disable(dev_priv);
> > @@ -1590,7 +1587,8 @@ static void cnl_set_cdclk(struct
> > drm_i915_private *dev_priv,
> >  	I915_WRITE(CDCLK_CTL, val);
> >  
> >  	/* inform PCU of the change */
> > -	cnl_dvfs_post_change(dev_priv, pcu_ack);
> > +	level = cnl_dvfs_new_level(cdclk, 0);
> > +	cnl_dvfs_post_change(dev_priv, level);
> >  
> >  	intel_update_cdclk(dev_priv);
> >  }
> > diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.c
> > b/drivers/gpu/drm/i915/intel_dpll_mgr.c
> > index a71a6c396bbd..0dddbd3a7a97 100644
> > --- a/drivers/gpu/drm/i915/intel_dpll_mgr.c
> > +++ b/drivers/gpu/drm/i915/intel_dpll_mgr.c
> > @@ -1966,16 +1966,6 @@ static const struct intel_dpll_mgr bxt_pll_mgr
> > = {
> >  	.dump_hw_state = bxt_dump_hw_state,
> >  };
> >  
> > -static int cnl_get_dvfs_level(int cdclk, int portclk)
> > -{
> > -	if (cdclk == 168000 && portclk <= 594000)
> > -		return 0;
> > -	else if (cdclk == 336000 && portclk <= 594000)
> > -		return 1;
> > -	else
> > -		return 2;
> > -}
> > -
> >  static void cnl_ddi_pll_enable(struct drm_i915_private *dev_priv,
> >  			       struct intel_shared_dpll *pll)
> >  {
> > @@ -2044,7 +2034,7 @@ static void cnl_ddi_pll_enable(struct
> > drm_i915_private *dev_priv,
> >  	if (ret == 0) {
> >  		cdclk = dev_priv->cdclk.hw.cdclk;
> >  		portclk = intel_ddi_port_clock(dev_priv, pll->id);
> > -		level = cnl_get_dvfs_level(cdclk, portclk);
> > +		level = cnl_dvfs_new_level(cdclk, portclk);
> >  		cnl_dvfs_post_change(dev_priv, level);
> >  	}
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > b/drivers/gpu/drm/i915/intel_drv.h
> > index 934ccf17f8ab..dec11d7b15ab 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1325,6 +1325,7 @@ void cnl_init_cdclk(struct drm_i915_private
> > *dev_priv);
> >  void cnl_uninit_cdclk(struct drm_i915_private *dev_priv);
> >  int cnl_dvfs_pre_change(struct drm_i915_private *dev_priv);
> >  void cnl_dvfs_post_change(struct drm_i915_private *dev_priv, int
> > level);
> > +int cnl_dvfs_new_level(int cdclk, int portclk);
> >  void bxt_init_cdclk(struct drm_i915_private *dev_priv);
> >  void bxt_uninit_cdclk(struct drm_i915_private *dev_priv);
> >  void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv);
> -- 
> Mika Kahola - Intel OTC
> 
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