Am 6. Januar 2026 13:21:32 MEZ schrieb Aswin Murugan <[email protected]>: >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 > *
Have a look at starfive_visionfive2_defconfig which supports several boards and chooses the right devicetree based on a value in an EEPROM in SPL. In main U-Boot it sets a board specific value in $fdtfile which allows loading a device-tree from directory dtb/ on the ESP to override the U-Boot device-tree. Best regards Heinrich
