[PATCH 2/8] FIT: skip possible overlay config nodes

[Marco Felsch <m.felsch@xxxxxxxxxxxxxx>]

The FIT spec is not very specific when it comes to device-tree overlay
handling. Overlays can be added directely to an config node:

	config-a {
		compatible = "machine-compatible";
		kernel = "kernel-img-name";
		fdt = "fdt-base-name", "fdt-overlay1-name", "...";
	}

or they are supplied via dedicated config nodes:

	overlay-2 {
		fdt = "fdt-overlay2-name";
	}

Of course these config nodes can have compatibles as well:

	overlay-3 {
		compatible = "machine-compatible";
		fdt = "fdt-overlay3-name";
	}

The current fit_find_compatible_unit() code would skip the overlay node
if the config-a compatible has the same score as the overlay-3
compatible and if the overlay-3 config-node is listed after the config-a
config-node. But if the compatible of config-a config-node has a lower
score or the overlay-3 config-note is listed first (the spec does not
specify any order) we end up in taking the overlay-3 config-node instead
of config-a config-node.

Make to code more robust by skip all config nodes matching the pattern
from global.of.overlay.fitconfigpattern.

Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx>
---
 common/image-fit.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/common/image-fit.c b/common/image-fit.c
index b16752de05bc..bf1562315b40 100644
--- a/common/image-fit.c
+++ b/common/image-fit.c
@@ -7,6 +7,7 @@
 
 #define pr_fmt(fmt) "FIT: " fmt
 #include <common.h>
+#include <environment.h>
 #include <init.h>
 #include <bootm.h>
 #include <libfile.h>
@@ -14,6 +15,7 @@
 #include <digest.h>
 #include <of.h>
 #include <fs.h>
+#include <fnmatch.h>
 #include <malloc.h>
 #include <linux/ctype.h>
 #include <asm/byteorder.h>
@@ -715,6 +717,23 @@ static int fit_config_verify_signature(struct fit_handle *handle, struct device_
 	return ret;
 }
 
+static bool fit_config_is_overlay(struct device_node *conf_node)
+{
+	const char *overlay_pattern;
+	int no_match;
+
+	if (!IS_ENABLED(CONFIG_OF_OVERLAY))
+		return false;
+
+	overlay_pattern = getenv_nonempty("global.of.overlay.fitconfigpattern");
+	if (!overlay_pattern)
+		return false;
+
+	no_match = fnmatch(overlay_pattern, conf_node->name, 0);
+
+	return no_match ? false : true;
+}
+
 static int fit_find_compatible_unit(struct device_node *conf_node,
 				    const char **unit)
 {
@@ -733,7 +752,12 @@ static int fit_find_compatible_unit(struct device_node *conf_node,
 		return -ENOENT;
 
 	for_each_child_of_node(conf_node, child) {
-		int score = of_device_is_compatible(child, machine);
+		int score;
+
+		if (fit_config_is_overlay(child))
+			continue;
+
+		score = of_device_is_compatible(child, machine);
 		if (score > best_score) {
 			best_score = score;
 			*unit = child->name;
-- 
2.39.2