drm/i915: Add engine scratch register to live_lrc_fixed

General purpose registers are per engine and
in a fixed location. Add to live_lrc_fixed.
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/20200424214841.28076-1-mika.kuoppala@linux.intel.com

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

@@ -250,6 +250,18 @@ static int lrc_ring_mi_mode(const struct intel_engine_cs *engine)
 		return -1;
 }
 
+static int lrc_ring_gpr0(const struct intel_engine_cs *engine)
+{
+	if (INTEL_GEN(engine->i915) >= 12)
+		return 0x74;
+	else if (INTEL_GEN(engine->i915) >= 9)
+		return 0x68;
+	else if (engine->class == RENDER_CLASS)
+		return 0xd8;
+	else
+		return -1;
+}
+
 static int lrc_ring_wa_bb_per_ctx(const struct intel_engine_cs *engine)
 {
 	if (INTEL_GEN(engine->i915) >= 12)

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

@@ -4613,6 +4613,11 @@ static int live_lrc_fixed(void *arg)
 				CTX_TIMESTAMP - 1,
 				"RING_CTX_TIMESTAMP"
 			},
+			{
+				i915_mmio_reg_offset(GEN8_RING_CS_GPR(engine->mmio_base, 0)),
+				lrc_ring_gpr0(engine),
+				"RING_CS_GPR0"
+			},
 			{ },
 		}, *t;
 		u32 *hw;