arm: stm32mp: add helper function stm32mp_is_closed()

Add the helper function stm32mp_is_closed() to check the "closed" state in
product life cycle, when product secrets have  been provisioned into the
device, by "secure secret provisioning" tools (SSP) for example.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/arch/arm/mach-stm32mp/cmd_stm32key.c b/arch/arm/mach-stm32mp/cmd_stm32key.c
index d6bf72d..6bfa678 100644
--- a/arch/arm/mach-stm32mp/cmd_stm32key.c
+++ b/arch/arm/mach-stm32mp/cmd_stm32key.c
@@ -618,3 +618,25 @@
 	U_BOOT_SUBCMD_MKENT(read, 2, 0, do_stm32key_read),
 	U_BOOT_SUBCMD_MKENT(fuse, 3, 0, do_stm32key_fuse),
 	U_BOOT_SUBCMD_MKENT(close, 2, 0, do_stm32key_close));
+
+/*
+ * Check the "closed" state in product life cycle, when product secrets have
+ * been provisioned into the device, by SSP tools for example.
+ * On closed devices, authentication is mandatory.
+ */
+bool stm32mp_is_closed(void)
+{
+	struct udevice *dev;
+	bool closed;
+	int ret;
+
+	ret = get_misc_dev(&dev);
+	if (ret)
+		return false;
+
+	ret = read_close_status(dev, false, &closed);
+	if (ret)
+		return false;
+
+	return closed;
+}