efi_loader: add device-path utils

Helpers to construct device-paths from devices, partitions, files, and
for parsing and manipulating device-paths.

For non-legacy devices, this will use u-boot's device-model to construct
device-paths which include bus hierarchy to construct device-paths.  For
legacy devices we still fake it, but slightly more convincingly.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 25398ba..29701af 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -220,6 +220,32 @@
 #define EFI_LOADER_BOUNCE_BUFFER_SIZE (64 * 1024 * 1024)
 #endif
 
+
+struct efi_device_path *efi_dp_next(const struct efi_device_path *dp);
+int efi_dp_match(struct efi_device_path *a, struct efi_device_path *b);
+struct efi_object *efi_dp_find_obj(struct efi_device_path *dp,
+				   struct efi_device_path **rem);
+unsigned efi_dp_size(const struct efi_device_path *dp);
+struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp);
+struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
+				      const struct efi_device_path *dp2);
+struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
+					   const struct efi_device_path *node);
+
+
+struct efi_device_path *efi_dp_from_dev(struct udevice *dev);
+struct efi_device_path *efi_dp_from_part(struct blk_desc *desc, int part);
+struct efi_device_path *efi_dp_from_file(struct blk_desc *desc, int part,
+					 const char *path);
+struct efi_device_path *efi_dp_from_eth(void);
+void efi_dp_split_file_path(struct efi_device_path *full_path,
+			    struct efi_device_path **device_path,
+			    struct efi_device_path **file_path);
+
+#define EFI_DP_TYPE(_dp, _type, _subtype) \
+	(((_dp)->type == DEVICE_PATH_TYPE_##_type) && \
+	 ((_dp)->sub_type == DEVICE_PATH_SUB_TYPE_##_subtype))
+
 /* Convert strings from normal C strings to uEFI strings */
 static inline void ascii2unicode(u16 *unicode, const char *ascii)
 {