[PATCH v7 31/31] fdt: Show build/runtime warnings based on devicetree source

[Simon Glass]

Show a warning at build time if the devicetree is built for a board which
normally should get it from a prior stage:

   Warning: Devicetree was built but is not normally used on this board

When running, if the devicetree failed to come from the expected source,
show a warning then also, e.g:

   U-Boot ...

   DRAM:  128 MiB
   Core:  42 devices, 11 uclasses, devicetree: separate
   Warning: Unexpected devicetree source (not from a prior stage)
   Warning: U-Boot may not function properly
   Flash: 64 MiB
   ...

These warnings should only appear if the board config has been changed, or
the prior stage is broken.

Signed-off-by: Simon Glass <sjg at chromium.org>

---

(no changes since v1)

 Makefile         | 3 +++
 common/board_r.c | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/Makefile b/Makefile
index a3f018f01e0..0059f10cbca 100644
--- a/Makefile
+++ b/Makefile
@@ -1107,6 +1107,9 @@ endif
 ifeq ($(CONFIG_DEPRECATED),y)
 	$(warning "You have deprecated configuration options enabled in your .config! Please check your configuration.")
 endif
+ifeq ($(CONFIG_OF_HAS_PRIOR_STAGE).$(CONFIG_OF_OMIT_DTB),y.)
+	@echo >&2 "Warning: Devicetree was built but is not normally used on this board"
+endif
 ifeq ($(CONFIG_OF_EMBED)$(CONFIG_EFI_APP),y)
 	@echo >&2 "===================== WARNING ======================"
 	@echo >&2 "CONFIG_OF_EMBED is enabled. This option should only"
diff --git a/common/board_r.c b/common/board_r.c
index 99adff14b39..6d520662dbb 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -598,6 +598,12 @@ static int dm_announce(void)
 		if (CONFIG_IS_ENABLED(OF_REAL))
 			printf(", devicetree: %s", fdtdec_get_srcname());
 		printf("\n");
+		if (IS_ENABLED(CONFIG_OF_HAS_PRIOR_STAGE) &&
+		    (gd->fdt_src == FDTSRC_SEPARATE ||
+		     gd->fdt_src == FDTSRC_EMBED)) {
+			printf("Warning: Unexpected devicetree source (not from a prior stage)");
+			printf("Warning: U-Boot may not function properly\n");
+		}
 	}
 
 	return 0;
-- 
2.34.1.400.ga245620fadb-goog