drm/nouveau: Add getparam for current PTIMER time.

This will be useful for computing GPU-CPU latency, including
GL_ARB_timer_query extension.
Signed-off-by: Marcin Kościelnicki <koriakin@0x04.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_state.c

@@ -913,6 +913,9 @@ int nouveau_ioctl_getparam(struct drm_device *dev, void *data,
 	case NOUVEAU_GETPARAM_VM_VRAM_BASE:
 		getparam->value = dev_priv->vm_vram_base;
 		break;
+	case NOUVEAU_GETPARAM_PTIMER_TIME:
+		getparam->value = dev_priv->engine.timer.read(dev);
+		break;
 	case NOUVEAU_GETPARAM_GRAPH_UNITS:
 		/* NV40 and NV50 versions are quite different, but register
 		 * address is the same. User is supposed to know the card

include/drm/nouveau_drm.h

@@ -79,6 +79,7 @@ struct drm_nouveau_gpuobj_free {
 #define NOUVEAU_GETPARAM_CHIPSET_ID      11
 #define NOUVEAU_GETPARAM_VM_VRAM_BASE    12
 #define NOUVEAU_GETPARAM_GRAPH_UNITS     13
+#define NOUVEAU_GETPARAM_PTIMER_TIME     14
 struct drm_nouveau_getparam {
 	uint64_t param;
 	uint64_t value;