efi_loader: fix setting PlatformLang

The UEFI variables PlatformLang and PlatformLangCodes specify the current
firmware language and the list of all available languages.

Currently their values are hard coded. With the patch a new configuration
variable EFI_PLATFORM_LANG_CODES is provided.

When initializing the UEFI subsystem this configuration variable is used to
initialize PlatformLangCodes. The value of variable PlatformLang is read.
If it is not set, the first language specified in EFI_PLATFORM_LANG_CODES
is used to initialize PlatformLang.

Suggested-by: Takahiro Akashi <takahiro.akashi@linaro.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

2 files changed, 67 insertions, 15 deletions

diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index a6489ca5343..50b050159c3 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -26,6 +26,16 @@ config EFI_UNICODE_CAPITALIZATION
 	  set, only the the correct handling of the letters of the codepage
 	  used by the FAT file system is ensured.
 
+config EFI_PLATFORM_LANG_CODES
+	string "Language codes supported by firmware"
+	depends on EFI_LOADER
+	default "en-US"
+	help
+	  This value is used to initialize the PlatformLangCodes variable. Its
+	  value is a semicolon (;) separated list of language codes in native
+	  RFC 4646 format, e.g. "en-US;de-DE". The first language code is used
+	  to initialize the PlatformLang variable.
+
 config EFI_LOADER_BOUNCE_BUFFER
 	bool "EFI Applications use bounce buffers for DMA operations"
 	depends on EFI_LOADER && ARM64
diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
index 6e9d5fe5b7a..b32a7b3f934 100644
--- a/lib/efi_loader/efi_setup.c
+++ b/lib/efi_loader/efi_setup.c
@@ -10,44 +10,86 @@
 
 #define OBJ_LIST_NOT_INITIALIZED 1
 
-/* Language code for American English according to RFC 4646 */
-#define EN_US L"en-US"
-
 static efi_status_t efi_obj_list_initialized = OBJ_LIST_NOT_INITIALIZED;
 
-/* Initialize and populate EFI object list */
-efi_status_t efi_init_obj_list(void)
+/**
+ * efi_init_platform_lang() - define supported languages
+ *
+ * Set the PlatformLangCodes and PlatformLang variables.
+ *
+ * Return:	status code
+ */
+static efi_status_t efi_init_platform_lang(void)
 {
-	efi_status_t ret = EFI_SUCCESS;
+	efi_status_t ret;
+	efi_uintn_t data_size = 0;
+	char *lang = CONFIG_EFI_PLATFORM_LANG_CODES;
+	char *pos;
 
 	/*
-	 * Variable PlatformLang defines the language that the machine has been
-	 * configured for.
+	 * Variable PlatformLangCodes defines the language codes that the
+	 * machine can support.
 	 */
-	ret = EFI_CALL(efi_set_variable(L"PlatformLang",
+	ret = EFI_CALL(efi_set_variable(L"PlatformLangCodes",
 					&efi_global_variable_guid,
 					EFI_VARIABLE_BOOTSERVICE_ACCESS |
 					EFI_VARIABLE_RUNTIME_ACCESS,
-					sizeof(EN_US), EN_US));
+					sizeof(CONFIG_EFI_PLATFORM_LANG_CODES),
+					CONFIG_EFI_PLATFORM_LANG_CODES));
 	if (ret != EFI_SUCCESS)
 		goto out;
 
 	/*
-	 * Variable PlatformLangCodes defines the language codes that the
-	 * machine can support.
+	 * Variable PlatformLang defines the language that the machine has been
+	 * configured for.
 	 */
-	ret = EFI_CALL(efi_set_variable(L"PlatformLangCodes",
+	ret = EFI_CALL(efi_get_variable(L"PlatformLang",
 					&efi_global_variable_guid,
+					NULL, &data_size, &pos));
+	if (ret == EFI_BUFFER_TOO_SMALL) {
+		/* The variable is already set. Do not change it. */
+		ret = EFI_SUCCESS;
+		goto out;
+	}
+
+	/*
+	 * The list of supported languages is semicolon separated. Use the first
+	 * language to initialize PlatformLang.
+	 */
+	pos = strchr(lang, ';');
+	if (pos)
+		*pos = 0;
+
+	ret = EFI_CALL(efi_set_variable(L"PlatformLang",
+					&efi_global_variable_guid,
+					EFI_VARIABLE_NON_VOLATILE |
 					EFI_VARIABLE_BOOTSERVICE_ACCESS |
 					EFI_VARIABLE_RUNTIME_ACCESS,
-					sizeof(EN_US), EN_US));
+					1 + strlen(lang), lang));
+out:
 	if (ret != EFI_SUCCESS)
-		goto out;
+		printf("EFI: cannot initialize platform language settings\n");
+	return ret;
+}
+
+/**
+ * efi_init_obj_list() - Initialize and populate EFI object list
+ *
+ * Return:	status code
+ */
+efi_status_t efi_init_obj_list(void)
+{
+	efi_status_t ret = EFI_SUCCESS;
 
 	/* Initialize once only */
 	if (efi_obj_list_initialized != OBJ_LIST_NOT_INITIALIZED)
 		return efi_obj_list_initialized;
 
+	/* Define supported languages */
+	ret = efi_init_platform_lang();
+	if (ret != EFI_SUCCESS)
+		goto out;
+
 	/* Initialize system table */
 	ret = efi_initialize_system_table();
 	if (ret != EFI_SUCCESS)