efi: stub: Pass EFI system table address to U-Boot payload

This updates the EFI stub codes to pass UEFI BIOS's system table
address to U-Boot payload so that U-Boot can utilize it.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

include/efi.h

@@ -248,6 +248,7 @@ enum efi_entry_t {
 	EFIET_END,	/* Signals this is the last (empty) entry */
 	EFIET_MEMORY_MAP,
 	EFIET_GOP_MODE,
+	EFIET_SYS_TABLE,
 
 	/* Number of entries */
 	EFIET_MEMORY_COUNT,
@@ -338,6 +339,15 @@ struct efi_entry_gopmode {
 	} info[];
 };
 
+/**
+ * struct efi_entry_systable - system table passed to U-Boot
+ *
+ * @sys_table:	EFI system table address
+ */
+struct efi_entry_systable {
+	efi_physical_addr_t sys_table;
+};
+
 static inline struct efi_mem_desc *efi_get_next_mem_desc(
 		struct efi_entry_memmap *map, struct efi_mem_desc *desc)
 {

lib/efi/efi_stub.c

@@ -277,6 +277,7 @@ efi_status_t EFIAPI efi_main(efi_handle_t image,
 	struct efi_entry_memmap map;
 	struct efi_gop *gop;
 	struct efi_entry_gopmode mode;
+	struct efi_entry_systable table;
 	efi_guid_t efi_gop_guid = EFI_GOP_GUID;
 	efi_uintn_t key, desc_size, size;
 	efi_status_t ret;
@@ -335,6 +336,9 @@ efi_status_t EFIAPI efi_main(efi_handle_t image,
 		return ret;
 	}
 
+	table.sys_table = (ulong)sys_table;
+	add_entry_addr(priv, EFIET_SYS_TABLE, &table, sizeof(table), NULL, 0);
+
 	ret = boot->exit_boot_services(image, key);
 	if (ret) {
 		/*