Introduce a weak function efi_load_platform_fdt() to allow platforms to provide custom device tree selection logic. This enables platforms with special requirements (such as multi-DTB selection based on hardware detection) to load fdt.
The default weak implementation does nothing, Platforms can provide a strong implementation to load platform-specific device trees. Signed-off-by: Aswin Murugan <[email protected]> --- include/efi_loader.h | 2 ++ lib/efi_loader/efi_bootmgr.c | 4 ++++ lib/efi_loader/efi_fdt.c | 23 +++++++++++++++++++++++ 3 files changed, 29 insertions(+) diff --git a/include/efi_loader.h b/include/efi_loader.h index 3e70ac07055..62c3df48f71 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -1303,4 +1303,6 @@ int efi_get_distro_fdt_name(char *fname, int size, int seq); void efi_load_distro_fdt(efi_handle_t handle, void **fdt, efi_uintn_t *fdt_size); +void efi_load_platform_fdt(efi_handle_t handle, void **fdt, efi_uintn_t *fdt_size); + #endif /* _EFI_LOADER_H */ diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c index a687f4d8e85..ed06a65feb7 100644 --- a/lib/efi_loader/efi_bootmgr.c +++ b/lib/efi_loader/efi_bootmgr.c @@ -1332,6 +1332,10 @@ efi_status_t efi_bootmgr_run(void *fdt) efi_load_distro_fdt(handle, &fdt_distro, &fdt_size); fdt = fdt_distro; } + if (!fdt) { + efi_load_platform_fdt(handle, &fdt_distro, &fdt_size); + fdt = fdt_distro; + } } /* diff --git a/lib/efi_loader/efi_fdt.c b/lib/efi_loader/efi_fdt.c index bfaa9cfc207..bfcfd933adf 100644 --- a/lib/efi_loader/efi_fdt.c +++ b/lib/efi_loader/efi_fdt.c @@ -78,6 +78,29 @@ int efi_get_distro_fdt_name(char *fname, int size, int seq) return 0; } +/** + * efi_load_platform_fdt() - Platform-specific FDT loading hook (weak) + * + * @handle: handle of loaded image + * @fdt: on return device-tree, must be freed via efi_free_pages() + * @fdt_size: buffer size + * + * This weak function allows platforms to provide custom DTB selection logic. + * The default implementation does nothing, allowing the standard distro boot + * path to handle FDT loading. Platforms can override this function to + * implement custom multi-DTB selection or other platform-specific logic. + * + * If this function successfully loads a DTB, it should set *fdt to point to + * the loaded DTB and return. If it cannot load a DTB, it should set *fdt to + * NULL, and the standard distro boot logic will be used as fallback. + */ +__weak void efi_load_platform_fdt(efi_handle_t handle, void **fdt, + efi_uintn_t *fdt_size) +{ + /* Default: do nothing, let standard distro boot handle it */ + *fdt = NULL; +} + /** * efi_load_distro_fdt() - load distro device-tree * -- 2.34.1
