efi_loader: Disable ANSI output for tests

We don't want ANSI escape-sequences written in tests since it is a pain
to check the output with ut_assert_nextline() et al.

Provide a way to tests to request that these characters not be sent.

Add a proper function comment while we are here, to encourage others.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

include/efi_loader.h

@@ -588,8 +588,27 @@ efi_status_t efi_bootmgr_delete_boot_option(u16 boot_index);
 efi_status_t efi_bootmgr_run(void *fdt);
 /* search the boot option index in BootOrder */
 bool efi_search_bootorder(u16 *bootorder, efi_uintn_t num, u32 target, u32 *index);
-/* Set up console modes */
+
+/**
+ * efi_setup_console_size() - update the mode table.
+ *
+ * By default the only mode available is 80x25. If the console has at least 50
+ * lines, enable mode 80x50. If we can query the console size and it is neither
+ * 80x25 nor 80x50, set it as an additional mode.
+ */
 void efi_setup_console_size(void);
+
+/**
+ * efi_console_set_ansi() - Set whether ANSI escape-characters should be emitted
+ *
+ * These characters mess up tests which use ut_assert_nextline(). Call this
+ * function to tell efi_loader not to emit these characters when starting up the
+ * terminal
+ *
+ * @allow_ansi: Allow emitting ANSI escape-characters
+ */
+void efi_console_set_ansi(bool allow_ansi);
+
 /* Set up load options from environment variable */
 efi_status_t efi_env_set_load_options(efi_handle_t handle, const char *env_var,
 				      u16 **load_options);