state: warn when a state node will be overwritten

This ports the following barebox commit:

| commit b30047b433a60e6183216e8364971efddd5d208e
| Author: Sascha Hauer <s.hauer@pengutronix.de>
| Date:   Thu May 4 11:58:23 2017 +0200
|
|     state: warn when a state node will be overwritten
|
|     People do not seem to know that a state node in the kernel
|     device tree will be overwritten by barebox. Print a warning
|     when this happens so that people can get an idea why changes
|     in the kernel device tree state node do not have any effect.
|
|     Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>
Signed-off-by: Roland Hieber <rhi@pengutronix.de>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/barebox-state/state.c b/src/barebox-state/state.c
index 9c4edb3..fda51db 100644
--- a/src/barebox-state/state.c
+++ b/src/barebox-state/state.c
@@ -416,6 +416,15 @@ static int of_state_fixup(struct device_node *root, void *ctx)
 	if (node) {
 		/* replace existing node - it will be deleted later */
 		parent = node->parent;
+
+		/*
+		 * barebox replaces the state node in the device tree it starts the
+		 * kernel with, so a state node that already exists in the device tree
+		 * will be overwritten. Warn about this so people do not wonder why
+		 * changes in the kernels state node do not have any effect.
+		 */
+		if (root != of_get_root_node())
+			dev_warn(&state->dev, "Warning: Kernel devicetree contains state node, replacing it\n");
 	} else {
 		char *of_path, *c;