drm/i915: Read guaranteed freq for valleyview

Reading RP1 for valleyview to help us enable "pm_rps" i-g-t testcase
execution.
Signed-off-by: Deepak S <deepak.s@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
[danvet: Add missing static.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -3810,6 +3810,17 @@ static int cherryview_rps_min_freq(struct drm_i915_private *dev_priv)
 	return rpn;
 }
 
+static int valleyview_rps_guar_freq(struct drm_i915_private *dev_priv)
+{
+	u32 val, rp1;
+
+	val = vlv_nc_read(dev_priv, IOSF_NC_FB_GFX_FREQ_FUSE);
+
+	rp1 = (val & FB_GFX_FGUARANTEED_FREQ_FUSE_MASK) >> FB_GFX_FGUARANTEED_FREQ_FUSE_SHIFT;
+
+	return rp1;
+}
+
 static int valleyview_rps_max_freq(struct drm_i915_private *dev_priv)
 {
 	u32 val, rp0;
@@ -3952,6 +3963,11 @@ static void valleyview_init_gt_powersave(struct drm_device *dev)
 			 vlv_gpu_freq(dev_priv, dev_priv->rps.efficient_freq),
 			 dev_priv->rps.efficient_freq);
 
+	dev_priv->rps.rp1_freq = valleyview_rps_guar_freq(dev_priv);
+	DRM_DEBUG_DRIVER("RP1(Guar Freq) GPU freq: %d MHz (%u)\n",
+			 vlv_gpu_freq(dev_priv, dev_priv->rps.rp1_freq),
+			 dev_priv->rps.rp1_freq);
+
 	dev_priv->rps.min_freq = valleyview_rps_min_freq(dev_priv);
 	DRM_DEBUG_DRIVER("min GPU freq: %d MHz (%u)\n",
 			 vlv_gpu_freq(dev_priv, dev_priv->rps.min_freq),