[Intel-gfx] [PATCH 3/4] drm/i915: Simplify vlv/chv rc6 residency calculation

[Ville Syrjälä]

On Mon, Sep 28, 2015 at 10:37:52PM +0300, Imre Deak wrote:
> On Thu, 2015-09-24 at 23:29 +0300, ville.syrjala at linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > We have the czclk freqeuency in dev_priv now, so let's just use it
>                    ^frequency
> > when converting the rc6 counters to milliseconds. This elimiantes
>                                                         ^eliminates

Someone needs to integrate a proper spell checker into checkpatch :)

> > a bunch of hairy code that essentially tries to extract the czclk
> > frequency using yet another method.
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Reviewed-by: Imre Deak <imre.deak at intel.com>
> 
> > ---
> >  drivers/gpu/drm/i915/i915_sysfs.c | 31 +++----------------------------
> >  1 file changed, 3 insertions(+), 28 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
> > index 55bd04c..74086eb 100644
> > --- a/drivers/gpu/drm/i915/i915_sysfs.c
> > +++ b/drivers/gpu/drm/i915/i915_sysfs.c
> > @@ -39,7 +39,7 @@ static u32 calc_residency(struct drm_device *dev, const u32 reg)
> >  {
> >  	struct drm_i915_private *dev_priv = dev->dev_private;
> >  	u64 raw_time; /* 32b value may overflow during fixed point math */
> > -	u64 units = 128ULL, div = 100000ULL, bias = 100ULL;
> > +	u64 units = 128ULL, div = 100000ULL;
> >  	u32 ret;
> >  
> >  	if (!intel_enable_rc6(dev))
> > @@ -49,41 +49,16 @@ static u32 calc_residency(struct drm_device *dev, const u32 reg)
> >  
> >  	/* On VLV and CHV, residency time is in CZ units rather than 1.28us */
> >  	if (IS_VALLEYVIEW(dev)) {
> > -		u32 clk_reg, czcount_30ns;
> > -
> > -		if (IS_CHERRYVIEW(dev))
> > -			clk_reg = CHV_CLK_CTL1;
> > -		else
> > -			clk_reg = VLV_CLK_CTL2;
> > -
> > -		czcount_30ns = I915_READ(clk_reg) >> CLK_CTL2_CZCOUNT_30NS_SHIFT;
> > -
> > -		if (!czcount_30ns) {
> > -			WARN(!czcount_30ns, "bogus CZ count value");
> > -			ret = 0;
> > -			goto out;
> > -		}
> > -
> > -		if (IS_CHERRYVIEW(dev) && czcount_30ns == 1) {
> > -			/* Special case for 320Mhz */
> > -			div = 10000000ULL;
> > -			units = 3125ULL;
> > -		} else {
> > -			czcount_30ns += 1;
> > -			div = 1000000ULL;
> > -			units = DIV_ROUND_UP_ULL(30ULL * bias, czcount_30ns);
> > -		}
> > +		units = 1;
> > +		div = dev_priv->czclk_freq;
> >  
> >  		if (I915_READ(VLV_COUNTER_CONTROL) & VLV_COUNT_RANGE_HIGH)
> >  			units <<= 8;
> > -
> > -		div = div * bias;
> >  	}
> >  
> >  	raw_time = I915_READ(reg) * units;
> >  	ret = DIV_ROUND_UP_ULL(raw_time, div);
> >  
> > -out:
> >  	intel_runtime_pm_put(dev_priv);
> >  	return ret;
> >  }
> 

-- 
Ville Syrjälä
Intel OTC