drm/etnaviv: enable debug registers on demand

Some performance register are debug register and they need to
be enabled in order to be functional.

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drivers/gpu/drm/etnaviv/etnaviv_gpu.c

@@ -1353,6 +1353,11 @@ static void sync_point_perfmon_sample_pre(struct etnaviv_gpu *gpu,
 	val &= ~VIVS_PM_POWER_CONTROLS_ENABLE_MODULE_CLOCK_GATING;
 	gpu_write(gpu, VIVS_PM_POWER_CONTROLS, val);
 
+	/* enable debug register */
+	val = gpu_read(gpu, VIVS_HI_CLOCK_CONTROL);
+	val &= ~VIVS_HI_CLOCK_CONTROL_DISABLE_DEBUG_REGISTERS;
+	gpu_write(gpu, VIVS_HI_CLOCK_CONTROL, val);
+
 	sync_point_perfmon_sample(gpu, event, ETNA_PM_PROCESS_PRE);
 }
 
@@ -1371,6 +1376,11 @@ static void sync_point_perfmon_sample_post(struct etnaviv_gpu *gpu,
 		*pmr->bo_vma = pmr->sequence;
 	}
 
+	/* disable debug register */
+	val = gpu_read(gpu, VIVS_HI_CLOCK_CONTROL);
+	val |= VIVS_HI_CLOCK_CONTROL_DISABLE_DEBUG_REGISTERS;
+	gpu_write(gpu, VIVS_HI_CLOCK_CONTROL, val);
+
 	/* enable clock gating */
 	val = gpu_read(gpu, VIVS_PM_POWER_CONTROLS);
 	val |= VIVS_PM_POWER_CONTROLS_ENABLE_MODULE_CLOCK_GATING;