drm/nouveau/fifo: perform reset from preinit

RM appears to do this really early in its initialisation, before DEVINIT.

We currently do this before BAR2 initialisation for some reason.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/include/nvkm/core/engine.h

@@ -15,6 +15,7 @@ struct nvkm_engine {
 
 struct nvkm_engine_func {
 	void *(*dtor)(struct nvkm_engine *);
+	void (*preinit)(struct nvkm_engine *);
 	int (*oneinit)(struct nvkm_engine *);
 	int (*init)(struct nvkm_engine *);
 	int (*fini)(struct nvkm_engine *, bool suspend);

drivers/gpu/drm/nouveau/nvkm/core/engine.c

@@ -126,6 +126,15 @@ nvkm_engine_init(struct nvkm_subdev *subdev)
 	return ret;
 }
 
+static int
+nvkm_engine_preinit(struct nvkm_subdev *subdev)
+{
+	struct nvkm_engine *engine = nvkm_engine(subdev);
+	if (engine->func->preinit)
+		engine->func->preinit(engine);
+	return 0;
+}
+
 static void *
 nvkm_engine_dtor(struct nvkm_subdev *subdev)
 {
@@ -138,6 +147,7 @@ nvkm_engine_dtor(struct nvkm_subdev *subdev)
 static const struct nvkm_subdev_func
 nvkm_engine_func = {
 	.dtor = nvkm_engine_dtor,
+	.preinit = nvkm_engine_preinit,
 	.init = nvkm_engine_init,
 	.fini = nvkm_engine_fini,
 	.intr = nvkm_engine_intr,

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

@@ -27,6 +27,7 @@
 #include <core/client.h>
 #include <core/gpuobj.h>
 #include <core/notify.h>
+#include <subdev/mc.h>
 
 #include <nvif/event.h>
 #include <nvif/unpack.h>
@@ -278,6 +279,12 @@ nvkm_fifo_oneinit(struct nvkm_engine *engine)
 	return 0;
 }
 
+static void
+nvkm_fifo_preinit(struct nvkm_engine *engine)
+{
+	nvkm_mc_reset(engine->subdev.device, NVKM_ENGINE_FIFO);
+}
+
 static int
 nvkm_fifo_init(struct nvkm_engine *engine)
 {
@@ -302,6 +309,7 @@ nvkm_fifo_dtor(struct nvkm_engine *engine)
 static const struct nvkm_engine_func
 nvkm_fifo = {
 	.dtor = nvkm_fifo_dtor,
+	.preinit = nvkm_fifo_preinit,
 	.oneinit = nvkm_fifo_oneinit,
 	.init = nvkm_fifo_init,
 	.fini = nvkm_fifo_fini,