efi: Add uclass for devices provided by UEFI firmware

UCLASS_EFI_LOADER is used for devices created by applications and
drivers loaded by U-Boots UEFI implementation.

This patch provides a new uclass (UCLASS_EFI_MEDIA) to be used for devices
that provided by a UEFI firmware calling U-Boot as an EFI application.

If the two uclasses can be unified, is left to future redesign.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 56a4eec..755fdcc 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -61,6 +61,29 @@
 	help
 	  This option enables the disk-block cache in TPL
 
+config EFI_MEDIA
+	bool "Support EFI media drivers"
+	default y if EFI || SANDBOX
+	help
+	  Enable this to support media devices on top of UEFI. This enables
+	  just the uclass so you also need a specific driver to make this do
+	  anything.
+
+	  For sandbox there is a test driver.
+
+if EFI_MEDIA
+
+config EFI_MEDIA_SANDBOX
+	bool "Sandbox EFI media driver"
+	depends on SANDBOX
+	default y
+	help
+	  Enables a simple sandbox media driver, used for testing just the
+	  EFI_MEDIA uclass. It does not do anything useful, since sandbox does
+	  not actually support running on top of UEFI.
+
+endif  # EFI_MEDIA
+
 config IDE
 	bool "Support IDE controllers"
 	select HAVE_BLOCK_DEVICE