drm/i915/dg2: Introduce Wa_18018764978

Wa_18018764978 applies to specific steppings of DG2 (G10 C0+,
G11 and G12 A0+). Clean up style in function at the same time.

Bspec: 66622
Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221123183648.407058-1-matthew.s.atwood@intel.com
(cherry picked from commit 468a4e63)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

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

@@ -457,6 +457,9 @@
 #define GEN8_L3CNTLREG				_MMIO(0x7034)
 #define   GEN8_ERRDETBCTRL			(1 << 9)
 
+#define PSS_MODE2				_MMIO(0x703c)
+#define   SCOREBOARD_STALL_FLUSH_CONTROL	REG_BIT(5)
+
 #define GEN7_SC_INSTDONE			_MMIO(0x7100)
 #define GEN12_SC_INSTDONE_EXTRA			_MMIO(0x7104)
 #define GEN12_SC_INSTDONE_EXTRA2		_MMIO(0x7108)

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

@@ -771,9 +771,14 @@ static void dg2_ctx_workarounds_init(struct intel_engine_cs *engine,
 
 	/* Wa_14014947963:dg2 */
 	if (IS_DG2_GRAPHICS_STEP(engine->i915, G10, STEP_B0, STEP_FOREVER) ||
-		IS_DG2_G11(engine->i915) || IS_DG2_G12(engine->i915))
+	    IS_DG2_G11(engine->i915) || IS_DG2_G12(engine->i915))
 		wa_masked_field_set(wal, VF_PREEMPTION, PREEMPTION_VERTEX_COUNT, 0x4000);
 
+	/* Wa_18018764978:dg2 */
+	if (IS_DG2_GRAPHICS_STEP(engine->i915, G10, STEP_C0, STEP_FOREVER) ||
+	    IS_DG2_G11(engine->i915) || IS_DG2_G12(engine->i915))
+		wa_masked_en(wal, PSS_MODE2, SCOREBOARD_STALL_FLUSH_CONTROL);
+
 	/* Wa_15010599737:dg2 */
 	wa_mcr_masked_en(wal, CHICKEN_RASTER_1, DIS_SF_ROUND_NEAREST_EVEN);
 }