drm/nouveau: add falcon interrupt handler

This prevents 100% cpu usage on fermi cards when the exit interrupt
from the secret scrubber is not acked.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/engine/bsp/nvc0.c

@@ -90,6 +90,7 @@ nvc0_bsp_ctor(struct nouveau_object *parent, struct nouveau_object *engine,
 		return ret;
 
 	nv_subdev(priv)->unit = 0x00008000;
+	nv_subdev(priv)->intr = nouveau_falcon_intr;
 	nv_engine(priv)->cclass = &nvc0_bsp_cclass;
 	nv_engine(priv)->sclass = nvc0_bsp_sclass;
 	return 0;

drivers/gpu/drm/nouveau/core/engine/bsp/nve0.c

@@ -90,6 +90,7 @@ nve0_bsp_ctor(struct nouveau_object *parent, struct nouveau_object *engine,
 		return ret;
 
 	nv_subdev(priv)->unit = 0x00008000;
+	nv_subdev(priv)->intr = nouveau_falcon_intr;
 	nv_engine(priv)->cclass = &nve0_bsp_cclass;
 	nv_engine(priv)->sclass = nve0_bsp_sclass;
 	return 0;

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

@@ -23,6 +23,25 @@
 #include <engine/falcon.h>
 #include <subdev/timer.h>
 
+void
+nouveau_falcon_intr(struct nouveau_subdev *subdev)
+{
+	struct nouveau_falcon *falcon = (void *)subdev;
+	u32 dispatch = nv_ro32(falcon, 0x01c);
+	u32 intr = nv_ro32(falcon, 0x008) & dispatch & ~(dispatch >> 16);
+
+	if (intr & 0x00000010) {
+		nv_debug(falcon, "ucode halted\n");
+		nv_wo32(falcon, 0x004, 0x00000010);
+		intr &= ~0x00000010;
+	}
+
+	if (intr)  {
+		nv_error(falcon, "unhandled intr 0x%08x\n", intr);
+		nv_wo32(falcon, 0x004, intr);
+	}
+}
+
 u32
 _nouveau_falcon_rd32(struct nouveau_object *object, u64 addr)
 {

drivers/gpu/drm/nouveau/core/engine/ppp/nvc0.c

@@ -90,6 +90,7 @@ nvc0_ppp_ctor(struct nouveau_object *parent, struct nouveau_object *engine,
 		return ret;
 
 	nv_subdev(priv)->unit = 0x00000002;
+	nv_subdev(priv)->intr = nouveau_falcon_intr;
 	nv_engine(priv)->cclass = &nvc0_ppp_cclass;
 	nv_engine(priv)->sclass = nvc0_ppp_sclass;
 	return 0;

drivers/gpu/drm/nouveau/core/engine/vp/nvc0.c

@@ -90,6 +90,7 @@ nvc0_vp_ctor(struct nouveau_object *parent, struct nouveau_object *engine,
 		return ret;
 
 	nv_subdev(priv)->unit = 0x00020000;
+	nv_subdev(priv)->intr = nouveau_falcon_intr;
 	nv_engine(priv)->cclass = &nvc0_vp_cclass;
 	nv_engine(priv)->sclass = nvc0_vp_sclass;
 	return 0;

drivers/gpu/drm/nouveau/core/engine/vp/nve0.c

@@ -90,6 +90,7 @@ nve0_vp_ctor(struct nouveau_object *parent, struct nouveau_object *engine,
 		return ret;
 
 	nv_subdev(priv)->unit = 0x00020000;
+	nv_subdev(priv)->intr = nouveau_falcon_intr;
 	nv_engine(priv)->cclass = &nve0_vp_cclass;
 	nv_engine(priv)->sclass = nve0_vp_sclass;
 	return 0;

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

@@ -72,6 +72,8 @@ int nouveau_falcon_create_(struct nouveau_object *, struct nouveau_object *,
 			   struct nouveau_oclass *, u32, bool, const char *,
 			   const char *, int, void **);
 
+void nouveau_falcon_intr(struct nouveau_subdev *subdev);
+
 #define _nouveau_falcon_dtor _nouveau_engine_dtor
 int  _nouveau_falcon_init(struct nouveau_object *);
 int  _nouveau_falcon_fini(struct nouveau_object *, bool);