drm/i915: Move residency calculation into intel_pm.c

Plan is to make generic residency calculation utility
function for usage outside of sysfs. As a first step
move residency calculation into intel_pm.c

Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index af0ac9f..ab723e3 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -42,32 +42,7 @@ static inline struct drm_i915_private *kdev_minor_to_i915(struct device *kdev)
 static u32 calc_residency(struct drm_i915_private *dev_priv,
 			  i915_reg_t reg)
 {
-	u64 raw_time; /* 32b value may overflow during fixed point math */
-	u64 units = 128ULL, div = 100000ULL;
-	u32 ret;
-
-	if (!intel_enable_rc6())
-		return 0;
-
-	intel_runtime_pm_get(dev_priv);
-
-	/* On VLV and CHV, residency time is in CZ units rather than 1.28us */
-	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
-		units = 1;
-		div = dev_priv->czclk_freq;
-
-		if (I915_READ(VLV_COUNTER_CONTROL) & VLV_COUNT_RANGE_HIGH)
-			units <<= 8;
-	} else if (IS_GEN9_LP(dev_priv)) {
-		units = 1;
-		div = 1200;		/* 833.33ns */
-	}
-
-	raw_time = I915_READ(reg) * units;
-	ret = DIV_ROUND_UP_ULL(raw_time, div);
-
-	intel_runtime_pm_put(dev_priv);
-	return ret;
+	return intel_rc6_residency(dev_priv, reg);
 }
 
 static ssize_t