[PATCH 1/4] drm/i915: update current freq properly before requesting new freq.

[deepak.s@intel.com]

From: Deepak S <deepak.s@intel.com>

on VLV, P-Unit doesn't garauntee that last requested freq by driver
is actually the current running frequency. We need to make sure we update
the cur freq. before requesitng new freq.

Signed-off-by: Deepak S <deepak.s@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h |  1 +
 drivers/gpu/drm/i915/i915_irq.c |  8 ++++++++
 drivers/gpu/drm/i915/intel_pm.c | 31 +++++++++++++++++++++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 780f815..a62ac0c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2416,6 +2416,7 @@ extern bool ironlake_set_drps(struct drm_device *dev, u8 val);
 extern void intel_init_pch_refclk(struct drm_device *dev);
 extern void gen6_set_rps(struct drm_device *dev, u8 val);
 extern void valleyview_set_rps(struct drm_device *dev, u8 val);
+extern bool vlv_update_rps_cur_delay(struct drm_i915_private *dev_priv);
 extern int valleyview_rps_max_freq(struct drm_i915_private *dev_priv);
 extern int valleyview_rps_min_freq(struct drm_i915_private *dev_priv);
 extern void intel_detect_pch(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2715600..4bde03a 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -982,6 +982,14 @@ static void gen6_pm_rps_work(struct work_struct *work)
 
 	mutex_lock(&dev_priv->rps.hw_lock);
 
+	/* Make sure we have current freq updated properly. Doing this
+	 * here becuase, on VLV, P-Unit doesnt garauntee that last requested
+	 * freq by driver is actually the current running frequency
+	 */
+
+	if (IS_VALLEYVIEW(dev_priv->dev))
+		vlv_update_rps_cur_delay(dev_priv);
+
 	adj = dev_priv->rps.last_adj;
 	if (pm_iir & GEN6_PM_RP_UP_THRESHOLD) {
 		if (adj > 0)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index e6d98fe..7f6c747 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3607,6 +3607,35 @@ void gen6_rps_boost(struct drm_i915_private *dev_priv)
 	mutex_unlock(&dev_priv->rps.hw_lock);
 }
 
+/*
+ * Wait until the previous freq change has completed,
+ * or the timeout elapsed, and then update our notion
+ * of the current GPU frequency.
+ */
+bool vlv_update_rps_cur_delay(struct drm_i915_private *dev_priv)
+{
+	u32 pval;
+
+	WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
+
+	if (wait_for(((pval = vlv_punit_read(dev_priv,
+				PUNIT_REG_GPU_FREQ_STS)) &
+					GENFREQSTATUS) == 0, 10))
+		DRM_DEBUG_DRIVER("timed out waiting for Punit\n");
+
+	pval >>= 8;
+
+	if (pval != dev_priv->rps.cur_delay)
+		DRM_DEBUG_DRIVER("Punit overrode GPU freq: %d MHz (%u) requested, but got %d Mhz (%u)\n",
+				vlv_gpu_freq(dev_priv, dev_priv->rps.cur_delay),
+				dev_priv->rps.cur_delay,
+				vlv_gpu_freq(dev_priv, pval), pval);
+
+	dev_priv->rps.cur_delay = pval;
+	return true;
+}
+
+
 void valleyview_set_rps(struct drm_device *dev, u8 val)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -3615,6 +3644,8 @@ void valleyview_set_rps(struct drm_device *dev, u8 val)
 	WARN_ON(val > dev_priv->rps.max_delay);
 	WARN_ON(val < dev_priv->rps.min_delay);
 
+	vlv_update_rps_cur_delay(dev_priv);
+
 	DRM_DEBUG_DRIVER("GPU freq request from %d MHz (%u) to %d MHz (%u)\n",
 			 vlv_gpu_freq(dev_priv, dev_priv->rps.cur_delay),
 			 dev_priv->rps.cur_delay,
-- 
1.8.4.2