drm/nouveau/vm: perform a bar flush when flushing vm

Appears to fix the regression from "drm/nvc0/vm: handle bar tlb flushes
internally".

nvidia always seems to do this flush after writing values.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/subdev/vm/nv50.c

@@ -27,6 +27,7 @@
 
 #include <subdev/timer.h>
 #include <subdev/fb.h>
+#include <subdev/bar.h>
 #include <subdev/vm.h>
 
 struct nv50_vmmgr_priv {
@@ -151,9 +152,12 @@ static void
 nv50_vm_flush(struct nouveau_vm *vm)
 {
 	struct nv50_vmmgr_priv *priv = (void *)vm->vmm;
+	struct nouveau_bar *bar = nouveau_bar(priv);
 	struct nouveau_engine *engine;
 	int i, vme;
 
+	bar->flush(bar);
+
 	mutex_lock(&nv_subdev(priv)->mutex);
 	for (i = 0; i < NVDEV_SUBDEV_NR; i++) {
 		if (!atomic_read(&vm->engref[i]))

drivers/gpu/drm/nouveau/core/subdev/vm/nvc0.c

@@ -29,6 +29,7 @@
 #include <subdev/fb.h>
 #include <subdev/vm.h>
 #include <subdev/ltcg.h>
+#include <subdev/bar.h>
 
 struct nvc0_vmmgr_priv {
 	struct nouveau_vmmgr base;
@@ -163,9 +164,12 @@ static void
 nvc0_vm_flush(struct nouveau_vm *vm)
 {
 	struct nvc0_vmmgr_priv *priv = (void *)vm->vmm;
+	struct nouveau_bar *bar = nouveau_bar(priv);
 	struct nouveau_vm_pgd *vpgd;
 	u32 type;
 
+	bar->flush(bar);
+
 	type = 0x00000001; /* PAGE_ALL */
 	if (atomic_read(&vm->engref[NVDEV_SUBDEV_BAR]))
 		type |= 0x00000004; /* HUB_ONLY */