drm/nouveau/top: add function to translate subdev index to mmu fault id

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

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

@@ -11,6 +11,7 @@ struct nvkm_top {
 u32 nvkm_top_reset(struct nvkm_device *, enum nvkm_devidx);
 u32 nvkm_top_intr(struct nvkm_device *, u32 intr, u64 *subdevs);
 u32 nvkm_top_intr_mask(struct nvkm_device *, enum nvkm_devidx);
+int nvkm_top_fault_id(struct nvkm_device *, enum nvkm_devidx);
 enum nvkm_devidx nvkm_top_fault(struct nvkm_device *, int fault);
 enum nvkm_devidx nvkm_top_engine(struct nvkm_device *, int, int *runl, int *engn);
 

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

@@ -95,6 +95,20 @@ nvkm_top_intr(struct nvkm_device *device, u32 intr, u64 *psubdevs)
 	return intr & ~handled;
 }
 
+int
+nvkm_top_fault_id(struct nvkm_device *device, enum nvkm_devidx devidx)
+{
+	struct nvkm_top *top = device->top;
+	struct nvkm_top_device *info;
+
+	list_for_each_entry(info, &top->device, head) {
+		if (info->index == devidx && info->fault >= 0)
+			return info->fault;
+	}
+
+	return -ENOENT;
+}
+
 enum nvkm_devidx
 nvkm_top_fault(struct nvkm_device *device, int fault)
 {