drm/i915: read current freq from Punit on VLV

Instead of returning the cached value, which is just what the kernel
requested.
Reviewed-by: NKenneth Graunke <kenneth@whitecape.org>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_sysfs.c

@@ -212,10 +212,13 @@ static ssize_t gt_cur_freq_mhz_show(struct device *kdev,
 	int ret;
 
 	mutex_lock(&dev_priv->rps.hw_lock);
-	if (IS_VALLEYVIEW(dev_priv->dev))
-		ret = vlv_gpu_freq(dev_priv->mem_freq, dev_priv->rps.cur_delay);
-	else
+	if (IS_VALLEYVIEW(dev_priv->dev)) {
+		u32 freq;
+		valleyview_punit_read(dev_priv, PUNIT_REG_GPU_FREQ_STS, &freq);
+		ret = vlv_gpu_freq(dev_priv->mem_freq, (freq >> 8) & 0xff);
+	} else {
 		ret = dev_priv->rps.cur_delay * GT_FREQUENCY_MULTIPLIER;
+	}
 	mutex_unlock(&dev_priv->rps.hw_lock);
 
 	return snprintf(buf, PAGE_SIZE, "%d\n", ret);