drm/i915/xelpg: Add Wa_14020495402

Disable clockgating for TDL SVHS fub.

v2: Implement in general render/compute wa's(MattR)

Bspec: 46045
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240318210025.562698-1-radhakrishna.sripada@intel.com

drivers/gpu/drm/i915/gt/intel_gt_regs.h

@@ -1215,6 +1215,7 @@
 #define   GEN12_DISABLE_EARLY_READ		REG_BIT(14)
 #define   GEN12_ENABLE_LARGE_GRF_MODE		REG_BIT(12)
 #define   GEN12_PUSH_CONST_DEREF_HOLD_DIS	REG_BIT(8)
+#define   XELPG_DISABLE_TDL_SVHS_GATING		REG_BIT(1)
 #define   GEN12_DISABLE_DOP_GATING              REG_BIT(0)
 
 #define RT_CTRL					MCR_REG(0xe530)

drivers/gpu/drm/i915/gt/intel_workarounds.c

@@ -2891,10 +2891,14 @@ general_render_compute_wa_init(struct intel_engine_cs *engine, struct i915_wa_li
 
 	if (IS_GFX_GT_IP_STEP(gt, IP_VER(12, 70), STEP_B0, STEP_FOREVER) ||
 	    IS_GFX_GT_IP_STEP(gt, IP_VER(12, 71), STEP_B0, STEP_FOREVER) ||
-	    IS_GFX_GT_IP_RANGE(gt, IP_VER(12, 74), IP_VER(12, 74)))
+	    IS_GFX_GT_IP_RANGE(gt, IP_VER(12, 74), IP_VER(12, 74))) {
 		/* Wa_14017856879 */
 		wa_mcr_masked_en(wal, GEN9_ROW_CHICKEN3, MTL_DISABLE_FIX_FOR_EOT_FLUSH);
 
+		/* Wa_14020495402 */
+		wa_mcr_masked_en(wal, GEN8_ROW_CHICKEN2, XELPG_DISABLE_TDL_SVHS_GATING);
+	}
+
 	if (IS_GFX_GT_IP_STEP(gt, IP_VER(12, 70), STEP_A0, STEP_B0) ||
 	    IS_GFX_GT_IP_STEP(gt, IP_VER(12, 71), STEP_A0, STEP_B0))
 		/*