drm/nouveau/fb/gp102-: unlock VPR right after devinit

Under memory load, instmem allocations could end up in the regions of
VRAM that are inaccessible right after boot, and be corrupted after a
suspend/resume cycle as a result of being restored before booting the
mem unlock firmware.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>

drivers/gpu/drm/nouveau/include/nvkm/subdev/fb.h

@@ -58,6 +58,8 @@ struct nvkm_fb {
 	struct nvkm_memory *mmu_wr;
 };
 
+int nvkm_fb_mem_unlock(struct nvkm_fb *);
+
 void nvkm_fb_tile_init(struct nvkm_fb *, int region, u32 addr, u32 size,
 		       u32 pitch, u32 flags, struct nvkm_fb_tile *);
 void nvkm_fb_tile_fini(struct nvkm_fb *, int region, struct nvkm_fb_tile *);

drivers/gpu/drm/nouveau/nvkm/engine/device/base.c

@@ -2808,6 +2808,10 @@ nvkm_device_preinit(struct nvkm_device *device)
 	if (ret)
 		goto fail;
 
+	ret = nvkm_fb_mem_unlock(device->fb);
+	if (ret)
+		goto fail;
+
 	time = ktime_to_us(ktime_get()) - time;
 	nvdev_trace(device, "preinit completed in %lldus\n", time);
 	return 0;

drivers/gpu/drm/nouveau/nvkm/subdev/fb/base.c

@@ -134,12 +134,20 @@ nvkm_fb_oneinit(struct nvkm_subdev *subdev)
 	return nvkm_mm_init(&fb->tags.mm, 0, 0, tags, 1);
 }
 
-static int
-nvkm_fb_init_scrub_vpr(struct nvkm_fb *fb)
+int
+nvkm_fb_mem_unlock(struct nvkm_fb *fb)
 {
 	struct nvkm_subdev *subdev = &fb->subdev;
 	int ret;
 
+	if (!fb->func->vpr.scrub_required)
+		return 0;
+
+	if (!fb->func->vpr.scrub_required(fb)) {
+		nvkm_debug(subdev, "VPR not locked\n");
+		return 0;
+	}
+
 	nvkm_debug(subdev, "VPR locked, running scrubber binary\n");
 
 	if (!fb->vpr_scrubber.size) {
@@ -194,13 +202,6 @@ nvkm_fb_init(struct nvkm_subdev *subdev)
 	if (fb->func->init_unkn)
 		fb->func->init_unkn(fb);
 
-	if (fb->func->vpr.scrub_required &&
-	    fb->func->vpr.scrub_required(fb)) {
-		ret = nvkm_fb_init_scrub_vpr(fb);
-		if (ret)
-			return ret;
-	}
-
 	return 0;
 }