drm/i915: Move skl/bxt gt specific workarounds to ring init

Some registers are, naturally, lost in gpu reset/suspend cycle.
And some registers, for example in display domain, are not subject
to gpu reset so they retain their contents.

As hang recovery triggers a reset, recoverable gpu hang can currently
flush out essential workarounds and cause havoc later on.

When register GEN8_GARBNTL is missing the WaEnableGapsTsvCreditFix:skl,
it can cause random system hangs [1]. This workaround was added in:
commit 245d96670d26 ("drm/i915:skl: Add WaEnableGapsTsvCreditFix")
But another set of system hangs were observed and the failure pattern
indicated that there was random gpu hang preceding the system hang [2].
This lead to the realization that we lose this workaround and BDW_SCRATCH1
on reset.

Add these workarounds setup in display init to skl/bxt ring init
where LRI workarounds are also setup. This way their setup is not
dependent on display side init.

References: [1] https://bugs.freedesktop.org/show_bug.cgi?id=90854
References: [2] https://bugs.freedesktop.org/show_bug.cgi?id=92315
Reported-by: Tomi Sarvela <tomix.p.sarvela@intel.com>
Cc: Tomi Sarvela <tomix.p.sarvela@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Tomi Sarvela <tomix.p.sarvela@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -52,56 +52,10 @@
 #define INTEL_RC6p_ENABLE			(1<<1)
 #define INTEL_RC6pp_ENABLE			(1<<2)
 
-static void gen9_init_clock_gating(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	/* WaEnableLbsSlaRetryTimerDecrement:skl */
-	I915_WRITE(BDW_SCRATCH1, I915_READ(BDW_SCRATCH1) |
-		   GEN9_LBS_SLA_RETRY_TIMER_DECREMENT_ENABLE);
-
-	/* WaDisableKillLogic:bxt,skl */
-	I915_WRITE(GAM_ECOCHK, I915_READ(GAM_ECOCHK) |
-		   ECOCHK_DIS_TLB);
-}
-
-static void skl_init_clock_gating(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	gen9_init_clock_gating(dev);
-
-	if (INTEL_REVID(dev) <= SKL_REVID_D0) {
-		/* WaDisableHDCInvalidation:skl */
-		I915_WRITE(GAM_ECOCHK, I915_READ(GAM_ECOCHK) |
-			   BDW_DISABLE_HDC_INVALIDATION);
-
-		/* WaDisableChickenBitTSGBarrierAckForFFSliceCS:skl */
-		I915_WRITE(FF_SLICE_CS_CHICKEN2,
-			   _MASKED_BIT_ENABLE(GEN9_TSG_BARRIER_ACK_DISABLE));
-	}
-
-	/* GEN8_L3SQCREG4 has a dependency with WA batch so any new changes
-	 * involving this register should also be added to WA batch as required.
-	 */
-	if (INTEL_REVID(dev) <= SKL_REVID_E0)
-		/* WaDisableLSQCROPERFforOCL:skl */
-		I915_WRITE(GEN8_L3SQCREG4, I915_READ(GEN8_L3SQCREG4) |
-			   GEN8_LQSC_RO_PERF_DIS);
-
-	/* WaEnableGapsTsvCreditFix:skl */
-	if (IS_SKYLAKE(dev) && (INTEL_REVID(dev) >= SKL_REVID_C0)) {
-		I915_WRITE(GEN8_GARBCNTL, (I915_READ(GEN8_GARBCNTL) |
-					   GEN9_GAPS_TSV_CREDIT_DISABLE));
-	}
-}
-
 static void bxt_init_clock_gating(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	gen9_init_clock_gating(dev);
-
 	/* WaDisableSDEUnitClockGating:bxt */
 	I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
 		   GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
@@ -112,17 +66,6 @@ static void bxt_init_clock_gating(struct drm_device *dev)
 	 */
 	I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
 		   GEN8_HDCUNIT_CLOCK_GATE_DISABLE_HDCREQ);
-
-	/* WaStoreMultiplePTEenable:bxt */
-	/* This is a requirement according to Hardware specification */
-	if (INTEL_REVID(dev) == BXT_REVID_A0)
-		I915_WRITE(TILECTL, I915_READ(TILECTL) | TILECTL_TLBPF);
-
-	/* WaSetClckGatingDisableMedia:bxt */
-	if (INTEL_REVID(dev) == BXT_REVID_A0) {
-		I915_WRITE(GEN7_MISCCPCTL, (I915_READ(GEN7_MISCCPCTL) &
-					    ~GEN8_DOP_CLOCK_GATE_MEDIA_ENABLE));
-	}
 }
 
 static void i915_pineview_get_mem_freq(struct drm_device *dev)
@@ -7109,9 +7052,6 @@ void intel_init_pm(struct drm_device *dev)
 		if (IS_BROXTON(dev))
 			dev_priv->display.init_clock_gating =
 				bxt_init_clock_gating;
-		else if (IS_SKYLAKE(dev))
-			dev_priv->display.init_clock_gating =
-				skl_init_clock_gating;
 		dev_priv->display.update_wm = skl_update_wm;
 		dev_priv->display.update_sprite_wm = skl_update_sprite_wm;
 	} else if (HAS_PCH_SPLIT(dev)) {

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -906,6 +906,14 @@ static int gen9_init_workarounds(struct intel_engine_cs *ring)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	uint32_t tmp;
 
+	/* WaEnableLbsSlaRetryTimerDecrement:skl */
+	I915_WRITE(BDW_SCRATCH1, I915_READ(BDW_SCRATCH1) |
+		   GEN9_LBS_SLA_RETRY_TIMER_DECREMENT_ENABLE);
+
+	/* WaDisableKillLogic:bxt,skl */
+	I915_WRITE(GAM_ECOCHK, I915_READ(GAM_ECOCHK) |
+		   ECOCHK_DIS_TLB);
+
 	/* WaDisablePartialInstShootdown:skl,bxt */
 	WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN,
 			  PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE);
@@ -1018,7 +1026,6 @@ static int skl_tune_iz_hashing(struct intel_engine_cs *ring)
 	return 0;
 }
 
-
 static int skl_init_workarounds(struct intel_engine_cs *ring)
 {
 	int ret;
@@ -1029,6 +1036,30 @@ static int skl_init_workarounds(struct intel_engine_cs *ring)
 	if (ret)
 		return ret;
 
+	if (INTEL_REVID(dev) <= SKL_REVID_D0) {
+		/* WaDisableHDCInvalidation:skl */
+		I915_WRITE(GAM_ECOCHK, I915_READ(GAM_ECOCHK) |
+			   BDW_DISABLE_HDC_INVALIDATION);
+
+		/* WaDisableChickenBitTSGBarrierAckForFFSliceCS:skl */
+		I915_WRITE(FF_SLICE_CS_CHICKEN2,
+			   _MASKED_BIT_ENABLE(GEN9_TSG_BARRIER_ACK_DISABLE));
+	}
+
+	/* GEN8_L3SQCREG4 has a dependency with WA batch so any new changes
+	 * involving this register should also be added to WA batch as required.
+	 */
+	if (INTEL_REVID(dev) <= SKL_REVID_E0)
+		/* WaDisableLSQCROPERFforOCL:skl */
+		I915_WRITE(GEN8_L3SQCREG4, I915_READ(GEN8_L3SQCREG4) |
+			   GEN8_LQSC_RO_PERF_DIS);
+
+	/* WaEnableGapsTsvCreditFix:skl */
+	if (IS_SKYLAKE(dev) && (INTEL_REVID(dev) >= SKL_REVID_C0)) {
+		I915_WRITE(GEN8_GARBCNTL, (I915_READ(GEN8_GARBCNTL) |
+					   GEN9_GAPS_TSV_CREDIT_DISABLE));
+	}
+
 	/* WaDisablePowerCompilerClockGating:skl */
 	if (INTEL_REVID(dev) == SKL_REVID_B0)
 		WA_SET_BIT_MASKED(HIZ_CHICKEN,
@@ -1072,6 +1103,17 @@ static int bxt_init_workarounds(struct intel_engine_cs *ring)
 	if (ret)
 		return ret;
 
+	/* WaStoreMultiplePTEenable:bxt */
+	/* This is a requirement according to Hardware specification */
+	if (INTEL_REVID(dev) == BXT_REVID_A0)
+		I915_WRITE(TILECTL, I915_READ(TILECTL) | TILECTL_TLBPF);
+
+	/* WaSetClckGatingDisableMedia:bxt */
+	if (INTEL_REVID(dev) == BXT_REVID_A0) {
+		I915_WRITE(GEN7_MISCCPCTL, (I915_READ(GEN7_MISCCPCTL) &
+					    ~GEN8_DOP_CLOCK_GATE_MEDIA_ENABLE));
+	}
+
 	/* WaDisableThreadStallDopClockGating:bxt */
 	WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN,
 			  STALL_DOP_GATING_DISABLE);