drm/i915: Agressive downclocking on Baytrail

Reuse the same reclocking strategy for Baytail as on its bigger brethren,
Sandybridge and Ivybridge. In particular, this makes the device quicker
to reclock (both up and down) though the tendency now is to downclock
more aggressively to compensate for the RPS boosts.

v2: Rebase
v3: Exclude Cherrytrail as Deepak was concerned that the increased
number of register writes would wake the common powerwell too often.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Deepak S <deepak.s@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1035,6 +1035,9 @@ struct intel_gen6_power_mgmt {
 	u8 rp0_freq;		/* Non-overclocked max frequency. */
 	u32 cz_freq;
 
+	u8 up_threshold; /* Current %busy required to uplock */
+	u8 down_threshold; /* Current %busy required to downclock */
+
 	int last_adj;
 	enum { LOW_POWER, BETWEEN, HIGH_POWER } power;
 

drivers/gpu/drm/i915/i915_irq.c

@@ -1049,15 +1049,15 @@ static u32 vlv_wa_c0_ei(struct drm_i915_private *dev_priv, u32 pm_iir)
 	if (pm_iir & GEN6_PM_RP_DOWN_EI_EXPIRED) {
 		if (!vlv_c0_above(dev_priv,
 				  &dev_priv->rps.down_ei, &now,
-				  VLV_RP_DOWN_EI_THRESHOLD))
+				  dev_priv->rps.down_threshold))
 			events |= GEN6_PM_RP_DOWN_THRESHOLD;
 		dev_priv->rps.down_ei = now;
 	}
 
 	if (pm_iir & GEN6_PM_RP_UP_EI_EXPIRED) {
 		if (vlv_c0_above(dev_priv,
 				 &dev_priv->rps.up_ei, &now,
-				 VLV_RP_UP_EI_THRESHOLD))
+				 dev_priv->rps.up_threshold))
 			events |= GEN6_PM_RP_UP_THRESHOLD;
 		dev_priv->rps.up_ei = now;
 	}

drivers/gpu/drm/i915/i915_reg.h

@@ -671,8 +671,6 @@ enum skl_disp_power_wells {
 #define   FB_FMAX_VMIN_FREQ_LO_MASK		0xf8000000
 
 #define VLV_CZ_CLOCK_TO_MILLI_SEC		100000
-#define VLV_RP_UP_EI_THRESHOLD			90
-#define VLV_RP_DOWN_EI_THRESHOLD		70
 
 /* vlv2 north clock has */
 #define CCK_FUSE_REG				0x8

drivers/gpu/drm/i915/intel_pm.c

@@ -3934,6 +3934,8 @@ static void gen6_set_rps_thresholds(struct drm_i915_private *dev_priv, u8 val)
 		    GEN6_RP_DOWN_IDLE_AVG);
 
 	dev_priv->rps.power = new_power;
+	dev_priv->rps.up_threshold = threshold_up;
+	dev_priv->rps.down_threshold = threshold_down;
 	dev_priv->rps.last_adj = 0;
 }
 
@@ -4005,8 +4007,11 @@ static void valleyview_set_rps(struct drm_device *dev, u8 val)
 		      "Odd GPU freq value\n"))
 		val &= ~1;
 
-	if (val != dev_priv->rps.cur_freq)
+	if (val != dev_priv->rps.cur_freq) {
 		vlv_punit_write(dev_priv, PUNIT_REG_GPU_FREQ_REQ, val);
+		if (!IS_CHERRYVIEW(dev_priv))
+			gen6_set_rps_thresholds(dev_priv, val);
+	}
 
 	I915_WRITE(GEN6_PMINTRMSK, gen6_rps_pm_mask(dev_priv, val));
 
@@ -4055,6 +4060,7 @@ static void vlv_set_rps_idle(struct drm_i915_private *dev_priv)
 				& GENFREQSTATUS) == 0, 100))
 		DRM_ERROR("timed out waiting for Punit\n");
 
+	gen6_set_rps_thresholds(dev_priv, val);
 	vlv_force_gfx_clock(dev_priv, false);
 
 	I915_WRITE(GEN6_PMINTRMSK, gen6_rps_pm_mask(dev_priv, val));