drm/i915/icl: WaDisableImprovedTdlClkGating

Revert to the legacy implementation.

v2: GEN7_ROW_CHICKEN2 is masked
v3:
  - Rebased
  - Renamed to Wa_2006611047
  - A0 and B0 only
v4:
  - Add spaces around '<<' (and fix the surrounding code as well)
  - Mark the WA as pre-prod
v5: Rebased on top of the WA refactoring
v6: Added References (Mika)
v7: Fixed in B0

References: HSDES#2006611047
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1527285939-20113-2-git-send-email-oscar.mateo@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -8328,8 +8328,9 @@ enum {
 
 #define GEN7_ROW_CHICKEN2		_MMIO(0xe4f4)
 #define GEN7_ROW_CHICKEN2_GT2		_MMIO(0xf4f4)
-#define   DOP_CLOCK_GATING_DISABLE	(1<<0)
-#define   PUSH_CONSTANT_DEREF_DISABLE	(1<<8)
+#define   DOP_CLOCK_GATING_DISABLE	(1 << 0)
+#define   PUSH_CONSTANT_DEREF_DISABLE	(1 << 8)
+#define   GEN11_TDL_CLOCK_GATING_FIX_DISABLE	(1 << 1)
 
 #define HSW_ROW_CHICKEN3		_MMIO(0xe49c)
 #define  HSW_ROW_CHICKEN3_L3_GLOBAL_ATOMICS_DISABLE    (1 << 6)

drivers/gpu/drm/i915/intel_workarounds.c

@@ -463,6 +463,13 @@ static int icl_ctx_workarounds_init(struct drm_i915_private *dev_priv)
 	 */
 	WA_SET_BIT_MASKED(ICL_HDC_MODE, HDC_FORCE_NON_COHERENT);
 
+	/* Wa_2006611047:icl (pre-prod)
+	 * Formerly known as WaDisableImprovedTdlClkGating
+	 */
+	if (IS_ICL_REVID(dev_priv, ICL_REVID_A0, ICL_REVID_A0))
+		WA_SET_BIT_MASKED(GEN7_ROW_CHICKEN2,
+				  GEN11_TDL_CLOCK_GATING_FIX_DISABLE);
+
 	return 0;
 }