drm/nouveau/sec2: dump tracepc info on halt

- useful to distinguish between different issues.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>

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

@@ -47,6 +47,7 @@ void gm200_flcn_bind_inst(struct nvkm_falcon *, int, u64);
 int gm200_flcn_bind_stat(struct nvkm_falcon *, bool);
 extern const struct nvkm_falcon_func_pio gm200_flcn_imem_pio;
 extern const struct nvkm_falcon_func_pio gm200_flcn_dmem_pio;
+void gm200_flcn_tracepc(struct nvkm_falcon *);
 
 int gp102_flcn_reset_eng(struct nvkm_falcon *);
 extern const struct nvkm_falcon_func_pio gp102_flcn_emem_pio;

drivers/gpu/drm/nouveau/nvkm/engine/sec2/gp102.c

@@ -178,6 +178,11 @@ gp102_sec2_intr(struct nvkm_inth *inth)
 	}
 
 	if (intr & 0x00000010) {
+		if (atomic_read(&sec2->running)) {
+			FLCN_ERR(falcon, "halted");
+			gm200_flcn_tracepc(falcon);
+		}
+
 		nvkm_falcon_wr32(falcon, 0x004, 0x00000010);
 		intr &= ~0x00000010;
 	}

drivers/gpu/drm/nouveau/nvkm/falcon/gm200.c

@@ -25,6 +25,21 @@
 #include <subdev/mc.h>
 #include <subdev/timer.h>
 
+void
+gm200_flcn_tracepc(struct nvkm_falcon *falcon)
+{
+	u32 sctl = nvkm_falcon_rd32(falcon, 0x240);
+	u32 tidx = nvkm_falcon_rd32(falcon, 0x148);
+	int nr = (tidx & 0x00ff0000) >> 16, sp, ip;
+
+	FLCN_ERR(falcon, "TRACEPC SCTL %08x TIDX %08x", sctl, tidx);
+	for (sp = 0; sp < nr; sp++) {
+		nvkm_falcon_wr32(falcon, 0x148, sp);
+		ip = nvkm_falcon_rd32(falcon, 0x14c);
+		FLCN_ERR(falcon, "TRACEPC: %08x", ip);
+	}
+}
+
 static void
 gm200_flcn_pio_dmem_rd(struct nvkm_falcon *falcon, u8 port, const u8 *img, int len)
 {