1 files changed, 122 insertions, 11 deletions

diff --git a/lib/efi_loader/efi_device_path_utilities.c b/lib/efi_loader/efi_device_path_utilities.c
index bc97eeee31..0ada2111db 100644
--- a/lib/efi_loader/efi_device_path_utilities.c
+++ b/lib/efi_loader/efi_device_path_utilities.c
@@ -12,69 +12,180 @@
 const efi_guid_t efi_guid_device_path_utilities_protocol =
 		EFI_DEVICE_PATH_UTILITIES_PROTOCOL_GUID;
 
+/*
+ * Get size of a device path.
+ *
+ * This function implements the GetDevicePathSize service of the device path
+ * utilities protocol. The device path length includes the end of path tag
+ * which may be an instance end.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ *
+ * @device_path		device path
+ * @return		size in bytes
+ */
 static efi_uintn_t EFIAPI get_device_path_size(
 	const struct efi_device_path *device_path)
 {
 	efi_uintn_t sz = 0;
 
-	EFI_ENTRY("%p", device_path);
+	EFI_ENTRY("%pD", device_path);
 	/* size includes the END node: */
 	if (device_path)
 		sz = efi_dp_size(device_path) + sizeof(struct efi_device_path);
 	return EFI_EXIT(sz);
 }
 
+/*
+ * Duplicate a device path.
+ *
+ * This function implements the DuplicateDevicePath service of the device path
+ * utilities protocol.
+ *
+ * The UEFI spec does not indicate what happens to the end tag. We follow the
+ * EDK2 logic: In case the device path ends with an end of instance tag, the
+ * copy will also end with an end of instance tag.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ *
+ * @device_path		device path
+ * @return		copy of the device path
+ */
 static struct efi_device_path * EFIAPI duplicate_device_path(
 	const struct efi_device_path *device_path)
 {
-	EFI_ENTRY("%p", device_path);
+	EFI_ENTRY("%pD", device_path);
 	return EFI_EXIT(efi_dp_dup(device_path));
 }
 
+/*
+ * Append device path.
+ *
+ * This function implements the AppendDevicePath service of the device path
+ * utilities protocol.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ *
+ * @src1		1st device path
+ * @src2		2nd device path
+ * @return		concatenated device path
+ */
 static struct efi_device_path * EFIAPI append_device_path(
 	const struct efi_device_path *src1,
 	const struct efi_device_path *src2)
 {
-	EFI_ENTRY("%p, %p", src1, src2);
+	EFI_ENTRY("%pD, %pD", src1, src2);
 	return EFI_EXIT(efi_dp_append(src1, src2));
 }
 
+/*
+ * Append device path node.
+ *
+ * This function implements the AppendDeviceNode service of the device path
+ * utilities protocol.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ *
+ * @device_path		device path
+ * @device_node		device node
+ * @return		concatenated device path
+ */
 static struct efi_device_path * EFIAPI append_device_node(
 	const struct efi_device_path *device_path,
 	const struct efi_device_path *device_node)
 {
-	EFI_ENTRY("%p, %p", device_path, device_node);
+	EFI_ENTRY("%pD, %p", device_path, device_node);
 	return EFI_EXIT(efi_dp_append_node(device_path, device_node));
 }
 
+/*
+ * Append device path instance.
+ *
+ * This function implements the AppendDevicePathInstance service of the device
+ * path utilities protocol.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ *
+ * @device_path			1st device path
+ * @device_path_instance	2nd device path
+ * @return			concatenated device path
+ */
 static struct efi_device_path * EFIAPI append_device_path_instance(
 	const struct efi_device_path *device_path,
 	const struct efi_device_path *device_path_instance)
 {
-	EFI_ENTRY("%p, %p", device_path, device_path_instance);
-	return EFI_EXIT(NULL);
+	EFI_ENTRY("%pD, %pD", device_path, device_path_instance);
+	return EFI_EXIT(efi_dp_append_instance(device_path,
+					       device_path_instance));
 }
 
+/*
+ * Get next device path instance.
+ *
+ * This function implements the GetNextDevicePathInstance service of the device
+ * path utilities protocol.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ *
+ * @device_path_instance	next device path instance
+ * @device_path_instance_size	size of the device path instance
+ * @return			concatenated device path
+ */
 static struct efi_device_path * EFIAPI get_next_device_path_instance(
 	struct efi_device_path **device_path_instance,
 	efi_uintn_t *device_path_instance_size)
 {
-	EFI_ENTRY("%p, %p", device_path_instance, device_path_instance_size);
-	return EFI_EXIT(NULL);
+	EFI_ENTRY("%pD, %p", device_path_instance, device_path_instance_size);
+	return EFI_EXIT(efi_dp_get_next_instance(device_path_instance,
+						 device_path_instance_size));
 }
 
+/*
+ * Check if a device path contains more than one instance.
+ *
+ * This function implements the AppendDeviceNode service of the device path
+ * utilities protocol.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ *
+ * @device_path		device path
+ * @device_node		device node
+ * @return		concatenated device path
+ */
 static bool EFIAPI is_device_path_multi_instance(
 	const struct efi_device_path *device_path)
 {
-	EFI_ENTRY("%p", device_path);
-	return EFI_EXIT(false);
+	EFI_ENTRY("%pD", device_path);
+	return EFI_EXIT(efi_dp_is_multi_instance(device_path));
 }
 
+/*
+ * Create device node.
+ *
+ * This function implements the CreateDeviceNode service of the device path
+ * utilities protocol.
+ *
+ * See the Unified Extensible Firmware Interface (UEFI) specification
+ * for details.
+ *
+ * @node_type		node type
+ * @node_sub_type	node sub type
+ * @node_length		node length
+ * @return		device path node
+ */
 static struct efi_device_path * EFIAPI create_device_node(
 	uint8_t node_type, uint8_t node_sub_type, uint16_t node_length)
 {
 	EFI_ENTRY("%u, %u, %u", node_type, node_sub_type, node_length);
-	return EFI_EXIT(NULL);
+	return EFI_EXIT(efi_dp_create_device_node(node_type, node_sub_type,
+			node_length));
 }
 
 const struct efi_device_path_utilities_protocol efi_device_path_utilities = {