efi: stub: Pass EFI GOP information to U-Boot payload

If UEFI BIOS has the graphics output protocol (GOP), let's pass its
information to U-Boot payload so that U-Boot can utilize it (eg:
an EFI framebuffer driver).

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/efi/efi_stub.c b/lib/efi/efi_stub.c
index 9deffe2..262fc56 100644
--- a/lib/efi/efi_stub.c
+++ b/lib/efi/efi_stub.c
@@ -275,6 +275,9 @@
 	struct efi_boot_services *boot = sys_table->boottime;
 	struct efi_mem_desc *desc;
 	struct efi_entry_memmap map;
+	struct efi_gop *gop;
+	struct efi_entry_gopmode mode;
+	efi_guid_t efi_gop_guid = EFI_GOP_GUID;
 	efi_uintn_t key, desc_size, size;
 	efi_status_t ret;
 	u32 version;
@@ -313,6 +316,18 @@
 	if (ret)
 		return ret;
 
+	ret = boot->locate_protocol(&efi_gop_guid, NULL, (void **)&gop);
+	if (ret) {
+		puts(" GOP unavailable\n");
+	} else {
+		mode.fb_base = gop->mode->fb_base;
+		mode.fb_size = gop->mode->fb_size;
+		mode.info_size = gop->mode->info_size;
+		add_entry_addr(priv, EFIET_GOP_MODE, &mode, sizeof(mode),
+			       gop->mode->info,
+			       sizeof(struct efi_gop_mode_info));
+	}
+
 	ret = boot->get_memory_map(&size, desc, &key, &desc_size, &version);
 	if (ret) {
 		printhex2(ret);