openwrt/target/linux/ipq806x/patches-5.4/900-arm-add-cmdline-override.patch

--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1840,6 +1840,14 @@ config ARM_ATAG_DTB_COMPAT_CMDLINE_MANGL
 
 endchoice
 
+config CMDLINE_OVERRIDE
+	bool "Use alternative cmdline from device tree"
+	help
+	  Some bootloaders may have uneditable bootargs. While CMDLINE_FORCE can
+	  be used, this is not a good option for kernels that are shared across
+	  devices. This setting enables using "chosen/cmdline-override" as the
+	  cmdline if it exists in the device tree.
+
 config CMDLINE
 	string "Default kernel command string"
 	default ""
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1060,6 +1060,17 @@ int __init early_init_dt_scan_chosen(uns
 	if (p != NULL && l > 0)
 		strlcpy(data, p, min(l, COMMAND_LINE_SIZE));
 
+    /* CONFIG_CMDLINE_OVERRIDE is used to fallback to a different
+     * device tree option of chosen/bootargs-override. This is
+     * helpful on boards where u-boot sets bootargs, and is unable
+     * to be modified.
+     */
+#ifdef CONFIG_CMDLINE_OVERRIDE
+	p = of_get_flat_dt_prop(node, "bootargs-override", &l);
+	if (p != NULL && l > 0)
+		strlcpy(data, p, min((int)l, COMMAND_LINE_SIZE));
+#endif
+
 	/*
 	 * CONFIG_CMDLINE is meant to be a default in case nothing else
 	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE