[PATCH] cmd: pxe_utils: sysboot: add label override support

[Amjad Ouled-Ameur]

This will allow consumers to choose a pxe label at runtime instead of
having to prompt the user. One good use-case for this, is choosing
whether or not to apply a dtbo depending on the hardware configuration.
e.g: for TI's AM335x EVM, it would be convenient to apply a particular
dtbo only when the J9 jumper is on PRUSS mode. To achieve this, the
pxe menu should have 2 labels, one with the dtbo and the other without,
then the "pxe_label_override" env variable should point to the label with
the dtbo at runtime only when the jumper is on PRUSS mode.

This change can be used for different use-cases and bring more
flexibilty to consumers who use sysboot/pxe_utils.

if "pxe_label_override" is set but does not exist in the pxe menu,
the code should fallback to the default label if given, and no failure
is returned but rather a warning message.

Signed-off-by: Amjad Ouled-Ameur <aouledameur at baylibre.com>

---

 cmd/pxe_utils.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/cmd/pxe_utils.c b/cmd/pxe_utils.c
index 067c24e5ff4b..b1009f9c7547 100644
--- a/cmd/pxe_utils.c
+++ b/cmd/pxe_utils.c
@@ -1354,9 +1354,11 @@ static struct menu *pxe_menu_to_menu(struct pxe_menu *cfg)
 	struct pxe_label *label;
 	struct list_head *pos;
 	struct menu *m;
+	char *label_override;
 	int err;
 	int i = 1;
 	char *default_num = NULL;
+	char *override_num = NULL;
 
 	/*
 	 * Create a menu and add items for all the labels.
@@ -1367,6 +1369,8 @@ static struct menu *pxe_menu_to_menu(struct pxe_menu *cfg)
 	if (!m)
 		return NULL;
 
+	label_override = env_get("pxe_label_override");
+
 	list_for_each(pos, &cfg->labels) {
 		label = list_entry(pos, struct pxe_label, list);
 
@@ -1375,11 +1379,22 @@ static struct menu *pxe_menu_to_menu(struct pxe_menu *cfg)
 			menu_destroy(m);
 			return NULL;
 		}
+		if (label_override &&
+		    (strcmp(label->name, label_override) == 0))
+			override_num = label->num;
 		if (cfg->default_label &&
 		    (strcmp(label->name, cfg->default_label) == 0))
 			default_num = label->num;
 	}
 
+	if (label_override) {
+		if (override_num)
+			default_num = override_num;
+		else
+			printf("Missing override pxe label: %s\n",
+					label_override);
+	}
+
 	/*
 	 * After we've created items for each label in the menu, set the
 	 * menu's default label if one was specified.
-- 
2.25.1