drm/i915/tgl: Wa_1409420604

Avoid possible hang in CPSS unit.
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191015154449.10338-6-mika.kuoppala@linux.intel.com

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

@@ -902,6 +902,11 @@ icl_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
 static void
 tgl_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
 {
+	/* Wa_1409420604:tgl */
+	if (IS_TGL_REVID(i915, TGL_REVID_A0, TGL_REVID_A0))
+		wa_write_or(wal,
+			    SUBSLICE_UNIT_LEVEL_CLKGATE2,
+			    CPSSUNIT_CLKGATE_DIS);
 }
 
 static void

drivers/gpu/drm/i915/i915_reg.h

@@ -4056,6 +4056,9 @@ enum {
 #define SUBSLICE_UNIT_LEVEL_CLKGATE	_MMIO(0x9524)
 #define  GWUNIT_CLKGATE_DIS		(1 << 16)
 
+#define SUBSLICE_UNIT_LEVEL_CLKGATE2	_MMIO(0x9528)
+#define  CPSSUNIT_CLKGATE_DIS		REG_BIT(9)
+
 #define UNSLICE_UNIT_LEVEL_CLKGATE	_MMIO(0x9434)
 #define  VFUNIT_CLKGATE_DIS		(1 << 20)