drm/i915: kill intel_resume_prepare()

Because, really, the abstraction is not working for us. It is nice for
VLV, but doesn't add anything useful on SNB/HSW/BDW. We want to change
this code due to a recently-discovered bug, but we can't seem to find
a nice solution that repects the current abstraction. So let's kill
intel_resume_prepare() and its friends, and add an equivalent
implementation to both its callers.

Also, look at the diffstat!

v2: - Rebase.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -551,8 +551,8 @@ static void intel_suspend_encoders(struct drm_i915_private *dev_priv)
 }
 
 static int intel_suspend_complete(struct drm_i915_private *dev_priv);
-static int intel_resume_prepare(struct drm_i915_private *dev_priv,
-				bool rpm_resume);
+static int vlv_resume_prepare(struct drm_i915_private *dev_priv,
+			      bool rpm_resume);
 
 static int i915_drm_suspend(struct drm_device *dev)
 {
@@ -744,7 +744,7 @@ static int i915_drm_resume(struct drm_device *dev)
 static int i915_drm_resume_early(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	int ret;
+	int ret = 0;
 
 	/*
 	 * We have a resume ordering issue with the snd-hda driver also
@@ -760,7 +760,10 @@ static int i915_drm_resume_early(struct drm_device *dev)
 
 	pci_set_master(dev->pdev);
 
-	ret = intel_resume_prepare(dev_priv, false);
+	if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
+		hsw_disable_pc8(dev_priv);
+	else if (IS_VALLEYVIEW(dev_priv))
+		ret = vlv_resume_prepare(dev_priv, false);
 	if (ret)
 		DRM_ERROR("Resume prepare failed: %d,Continuing resume\n", ret);
 
@@ -986,25 +989,6 @@ static int hsw_suspend_complete(struct drm_i915_private *dev_priv)
 	return 0;
 }
 
-static int snb_resume_prepare(struct drm_i915_private *dev_priv,
-				bool rpm_resume)
-{
-	struct drm_device *dev = dev_priv->dev;
-
-	if (rpm_resume)
-		intel_init_pch_refclk(dev);
-
-	return 0;
-}
-
-static int hsw_resume_prepare(struct drm_i915_private *dev_priv,
-				bool rpm_resume)
-{
-	hsw_disable_pc8(dev_priv);
-
-	return 0;
-}
-
 /*
  * Save all Gunit registers that may be lost after a D3 and a subsequent
  * S0i[R123] transition. The list of registers needing a save/restore is
@@ -1462,7 +1446,7 @@ static int intel_runtime_resume(struct device *device)
 	struct pci_dev *pdev = to_pci_dev(device);
 	struct drm_device *dev = pci_get_drvdata(pdev);
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	int ret;
+	int ret = 0;
 
 	if (WARN_ON_ONCE(!HAS_RUNTIME_PM(dev)))
 		return -ENODEV;
@@ -1472,7 +1456,13 @@ static int intel_runtime_resume(struct device *device)
 	intel_opregion_notify_adapter(dev, PCI_D0);
 	dev_priv->pm.suspended = false;
 
-	ret = intel_resume_prepare(dev_priv, true);
+	if (IS_GEN6(dev_priv))
+		intel_init_pch_refclk(dev);
+	else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
+		hsw_disable_pc8(dev_priv);
+	else if (IS_VALLEYVIEW(dev_priv))
+		ret = vlv_resume_prepare(dev_priv, true);
+
 	/*
 	 * No point of rolling back things in case of an error, as the best
 	 * we can do is to hope that things will still work (and disable RPM).
@@ -1510,29 +1500,6 @@ static int intel_suspend_complete(struct drm_i915_private *dev_priv)
 	return ret;
 }
 
-/*
- * This function implements common functionality of runtime and system
- * resume sequence. Variable rpm_resume used for implementing different
- * code paths.
- */
-static int intel_resume_prepare(struct drm_i915_private *dev_priv,
-				bool rpm_resume)
-{
-	struct drm_device *dev = dev_priv->dev;
-	int ret;
-
-	if (IS_GEN6(dev))
-		ret = snb_resume_prepare(dev_priv, rpm_resume);
-	else if (IS_HASWELL(dev) || IS_BROADWELL(dev))
-		ret = hsw_resume_prepare(dev_priv, rpm_resume);
-	else if (IS_VALLEYVIEW(dev))
-		ret = vlv_resume_prepare(dev_priv, rpm_resume);
-	else
-		ret = 0;
-
-	return ret;
-}
-
 static const struct dev_pm_ops i915_pm_ops = {
 	/*
 	 * S0ix (via system suspend) and S3 event handlers [PMSG_SUSPEND,