1 /* 2 * Copyright (C) 2016-2024 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef UFDT_OVERLAY_H 18 #define UFDT_OVERLAY_H 19 20 #include <libfdt.h> 21 22 /* Given a buffer in RAM containing the contents of a .dtb file, 23 * it initializes an FDT in-place and returns a pointer to the 24 * given buffer, or NULL in case of error. 25 * In case of error, it may printf() diagnostic messages. 26 */ 27 struct fdt_header *ufdt_install_blob(void *blob, size_t blob_size); 28 29 /* Given a main_fdt_header buffer and an overlay_fdtp buffer containing the 30 * contents of a .dtbo file, it creates a new FDT containing the applied 31 * overlay_fdtp in a dto_malloc'd buffer and returns it, or NULL in case of 32 * error. 33 * It is allowed to modify the buffers (both main_fdt_header and overlay_fdtp 34 * buffer) passed in. 35 * It does not dto_free main_fdt_header and overlay_fdtp buffer passed in. 36 */ 37 struct fdt_header *ufdt_apply_overlay(struct fdt_header *main_fdt_header, 38 size_t main_fdt_size, 39 void *overlay_fdtp, 40 size_t overlay_size); 41 42 /* 43 * Apply device tree `overlays` to `main_fdt_header` fdt buffer. (API is unstable) 44 * 45 * `main_fdt_header` is getting overrided by result tree, so it must 46 * have enough space (provided by `main_fdt_buffer_size`) to store it. 47 * `main_fdt_header` and all `overlays` must be 8 bytes aligned. 48 * 49 * `dto_malloc` is used for: 50 * - ufdt structures around main fdt and overlays. 51 * - result tree temporary buffer at most `main_fdt_buffer_size` size. 52 * 53 * TODO(b/362830550): expose a more comprehensive error type. 54 * Returns 0 or -1 in case of error. 55 */ 56 int ufdt_apply_multioverlay(struct fdt_header *main_fdt_header, 57 size_t main_fdt_buffer_size, void *const *overlays, 58 size_t overlays_count); 59 60 #endif /* UFDT_OVERLAY_H */ 61