efi: Locate all block devices in the app

When starting the app, locate all block devices and make them available
to U-Boot. This allows listing partitions and accessing files in
filesystems.

EFI also has the concept of 'disks', meaning boot media. For now, this
is not obviously useful in U-Boot, but add code to at least locate these.
This can be expanded later as needed.

We cannot use printf() in the early stub or app since it is not compiled
in

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/include/efi.h b/include/efi.h
index 1432038..cd0bdcc 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -419,10 +419,12 @@
  *
  * @handle: handle of the controller on which this driver is installed
  * @blkio: block io protocol proxied by this driver
+ * @device_path: EFI path to the device
  */
 struct efi_media_plat {
-	efi_handle_t		handle;
-	struct efi_block_io	*blkio;
+	efi_handle_t handle;
+	struct efi_block_io *blkio;
+	struct efi_device_path *device_path;
 };
 
 /* Base address of the EFI image */
diff --git a/include/efi_api.h b/include/efi_api.h
index 80109f0..ec9fa89 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -2035,4 +2035,19 @@
 			const u16 *package_version_name);
 };
 
+#define EFI_DISK_IO_PROTOCOL_GUID	\
+	EFI_GUID(0xce345171, 0xba0b, 0x11d2, 0x8e, 0x4f, \
+		 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
+
+struct efi_disk {
+	u64 revision;
+	efi_status_t (EFIAPI *read_disk)(struct efi_disk *this, u32 media_id,
+					 u64 offset, efi_uintn_t buffer_size,
+					 void *buffer);
+
+	efi_status_t (EFIAPI *write_disk)(struct efi_disk *this, u32 media_id,
+					  u64 offset, efi_uintn_t buffer_size,
+					  void *buffer);
+};
+
 #endif