drm/nouveau/devinit/gf100-: detect if BIOS invoked devinit

It is not advisable to perform devinit if it has already been done.
VBIOS will very likely have invoked devinit if the GPU is the primary
graphics device, but there is no accurate way to detect this fact yet.

This patch adds such a method for gf100 and later chips, by means of the
NV_PTOP_SCRATCH1_DEVINIT_COMPLETED bit. This bit is set to 1 by devinit,
and reset to 0 when the GPU is powered.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/subdev/devinit/gf100.c

@@ -90,9 +90,21 @@ gf100_devinit_disable(struct nvkm_devinit *init)
 	return disable;
 }
 
+void
+gf100_devinit_preinit(struct nvkm_devinit *base)
+{
+	struct nv50_devinit *init = nv50_devinit(base);
+	struct nvkm_subdev *subdev = &init->base.subdev;
+	struct nvkm_device *device = subdev->device;
+
+	/* This bit is set by devinit, and flips back to 0 on suspend */
+	if (!base->post)
+		base->post = ((nvkm_rd32(device, 0x2240c) & BIT(1)) == 0);
+}
+
 static const struct nvkm_devinit_func
 gf100_devinit = {
-	.preinit = nv50_devinit_preinit,
+	.preinit = gf100_devinit_preinit,
 	.init = nv50_devinit_init,
 	.post = nv04_devinit_post,
 	.pll_set = gf100_devinit_pll_set,

drivers/gpu/drm/nouveau/nvkm/subdev/devinit/gm107.c

@@ -46,7 +46,7 @@ gm107_devinit_disable(struct nvkm_devinit *init)
 
 static const struct nvkm_devinit_func
 gm107_devinit = {
-	.preinit = nv50_devinit_preinit,
+	.preinit = gf100_devinit_preinit,
 	.init = nv50_devinit_init,
 	.post = nv04_devinit_post,
 	.pll_set = gf100_devinit_pll_set,

drivers/gpu/drm/nouveau/nvkm/subdev/devinit/gm200.c

@@ -166,7 +166,7 @@ gm200_devinit_post(struct nvkm_devinit *base, bool post)
 
 static const struct nvkm_devinit_func
 gm200_devinit = {
-	.preinit = nv50_devinit_preinit,
+	.preinit = gf100_devinit_preinit,
 	.init = nv50_devinit_init,
 	.post = gm200_devinit_post,
 	.pll_set = gf100_devinit_pll_set,

drivers/gpu/drm/nouveau/nvkm/subdev/devinit/nv50.h

@@ -20,6 +20,7 @@ int  gf100_devinit_ctor(struct nvkm_object *, struct nvkm_object *,
 			struct nvkm_oclass *, void *, u32,
 			struct nvkm_object **);
 int  gf100_devinit_pll_set(struct nvkm_devinit *, u32, u32);
+void gf100_devinit_preinit(struct nvkm_devinit *);
 
 u64  gm107_devinit_disable(struct nvkm_devinit *);
 #endif