drm/i915: Use czclk_freq in vlv c0 residency calculations

Replace the use of mem_freq/4 with czclk_freq in the vlv c0 residency
calculations.

Also deal with VLV_COUNT_RANGE_HIGH which affects all RCx residency
counters. We have just enough bits to do this without intermediate
divisions.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

@@ -997,12 +997,16 @@ static bool vlv_c0_above(struct drm_i915_private *dev_priv,
 			 int threshold)
 {
 	u64 time, c0;
+	unsigned int mul = 100;
 
 	if (old->cz_clock == 0)
 		return false;
 
+	if (I915_READ(VLV_COUNTER_CONTROL) & VLV_COUNT_RANGE_HIGH)
+		mul <<= 8;
+
 	time = now->cz_clock - old->cz_clock;
-	time *= threshold * dev_priv->mem_freq;
+	time *= threshold * dev_priv->czclk_freq;
 
 	/* Workload can be split between render + media, e.g. SwapBuffers
 	 * being blitted in X after being rendered in mesa. To account for
@@ -1010,7 +1014,7 @@ static bool vlv_c0_above(struct drm_i915_private *dev_priv,
 	 */
 	c0 = now->render_c0 - old->render_c0;
 	c0 += now->media_c0 - old->media_c0;
-	c0 *= 100 * VLV_CZ_CLOCK_TO_MILLI_SEC * 4 / 1000;
+	c0 *= mul * VLV_CZ_CLOCK_TO_MILLI_SEC;
 
 	return c0 >= time;
 }