[PATCH v8 24/32] fdt: Don't call board_fdt_blob_setup() without OF_BOARD

[Simon Glass]

At present this override function is called even when OF_BOARD is not
enabled. This makes it impossible to disable this feature and in fact
makes the OF_BOARD option useless.

Reinstate its intended purpose, so that it is possible to switch between
the appended devicetree and one provided by the board's custom function.

A follower patch adds warnings for this scenario, but for now we don't
have a Kconfig that definitively tells us that OF_BOARD should be used.

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

Changes in v8:
- Mention the follower patch

Changes in v7:
- Fix 'Is' typo in commit message

Changes in v5:
- Add new patches to clean up fdtdec_setup() and surrounds

 include/fdtdec.h |  7 +++++--
 lib/fdtdec.c     | 21 ++++++++++++---------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/include/fdtdec.h b/include/fdtdec.h
index 68786111a44..68a36f10583 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -1170,10 +1170,13 @@ int fdtdec_resetup(int *rescan);
 
 /**
  * Board-specific FDT initialization. Returns the address to a device tree blob.
- * Called when CONFIG_OF_BOARD is defined, or if CONFIG_OF_SEPARATE is defined
- * and the board implements it.
+ *
+ * Called when CONFIG_OF_BOARD is defined.
+ *
+ * The existing devicetree is available at gd->fdt_blob
  *
  * @err internal error code if we fail to setup a DTB
+ * @returns new devicetree blob pointer
  */
 void *board_fdt_blob_setup(int *err);
 
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index a7f62123a94..31a509bc221 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -1203,15 +1203,15 @@ static int uncompress_blob(const void *src, ulong sz_src, void **dstp)
 	return 0;
 }
 
-/*
- * For CONFIG_OF_SEPARATE, the board may optionally implement this to
- * provide and/or fixup the fdt.
+/**
+ * fdt_find_separate() - Find a devicetree at the end of the image
+ *
+ * @return pointer to FDT blob
  */
-__weak void *board_fdt_blob_setup(int *err)
+static void *fdt_find_separate(void)
 {
 	void *fdt_blob = NULL;
 
-	*err = 0;
 #ifdef CONFIG_SPL_BUILD
 	/* FDT is at end of BSS unless it is in a different memory region */
 	if (IS_ENABLED(CONFIG_SPL_SEPARATE_BSS))
@@ -1626,13 +1626,16 @@ int fdtdec_setup(void)
 	int ret;
 
 	/* The devicetree is typically appended to U-Boot */
-	if (IS_ENABLED(CONFIG_OF_SEPARATE) || IS_ENABLED(CONFIG_OF_BOARD)) {
-		/* Allow the board to override the fdt address. */
+	if (IS_ENABLED(CONFIG_OF_SEPARATE))
+		gd->fdt_blob = fdt_find_separate();
+	else /* embed dtb in ELF file for testing / development */
+		gd->fdt_blob = dtb_dt_embedded();
+
+	/* Allow the board to override the fdt address. */
+	if (IS_ENABLED(CONFIG_OF_BOARD)) {
 		gd->fdt_blob = board_fdt_blob_setup(&ret);
 		if (ret)
 			return ret;
-	} else { /* embed dtb in ELF file for testing / development */
-		gd->fdt_blob = dtb_dt_embedded();
 	}
 
 	if (!IS_ENABLED(CONFIG_SPL_BUILD)) {
-- 
2.34.1.173.g76aa8bc2d0-goog