[efi] Add helper functions for service binding protocols

The EFI service binding abstraction is used to add and remove child
handles for multiple different protocols.  Provide a common interface
for doing so.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/efi/Protocol/ServiceBinding.h

@@ -0,0 +1,90 @@
+/** @file
+  UEFI Service Binding Protocol is defined in UEFI specification.
+
+  The file defines the generic Service Binding Protocol functions.
+  It provides services that are required to create and destroy child
+  handles that support a given set of protocols.
+
+  Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef __EFI_SERVICE_BINDING_H__
+#define __EFI_SERVICE_BINDING_H__
+
+FILE_LICENCE ( BSD2_PATENT );
+
+///
+/// Forward reference for pure ANSI compatability
+///
+typedef struct _EFI_SERVICE_BINDING_PROTOCOL EFI_SERVICE_BINDING_PROTOCOL;
+
+/**
+  Creates a child handle and installs a protocol.
+
+  The CreateChild() function installs a protocol on ChildHandle.
+  If ChildHandle is a pointer to NULL, then a new handle is created and returned in ChildHandle.
+  If ChildHandle is not a pointer to NULL, then the protocol installs on the existing ChildHandle.
+
+  @param  This        Pointer to the EFI_SERVICE_BINDING_PROTOCOL instance.
+  @param  ChildHandle Pointer to the handle of the child to create. If it is NULL,
+                      then a new handle is created. If it is a pointer to an existing UEFI handle,
+                      then the protocol is added to the existing UEFI handle.
+
+  @retval EFI_SUCCES            The protocol was added to ChildHandle.
+  @retval EFI_INVALID_PARAMETER ChildHandle is NULL.
+  @retval EFI_OUT_OF_RESOURCES  There are not enough resources available to create
+                                the child
+  @retval other                 The child handle was not created
+
+**/
+typedef
+EFI_STATUS
+(EFIAPI *EFI_SERVICE_BINDING_CREATE_CHILD)(
+  IN     EFI_SERVICE_BINDING_PROTOCOL  *This,
+  IN OUT EFI_HANDLE                    *ChildHandle
+  );
+
+/**
+  Destroys a child handle with a protocol installed on it.
+
+  The DestroyChild() function does the opposite of CreateChild(). It removes a protocol
+  that was installed by CreateChild() from ChildHandle. If the removed protocol is the
+  last protocol on ChildHandle, then ChildHandle is destroyed.
+
+  @param  This        Pointer to the EFI_SERVICE_BINDING_PROTOCOL instance.
+  @param  ChildHandle Handle of the child to destroy
+
+  @retval EFI_SUCCES            The protocol was removed from ChildHandle.
+  @retval EFI_UNSUPPORTED       ChildHandle does not support the protocol that is being removed.
+  @retval EFI_INVALID_PARAMETER Child handle is NULL.
+  @retval EFI_ACCESS_DENIED     The protocol could not be removed from the ChildHandle
+                                because its services are being used.
+  @retval other                 The child handle was not destroyed
+
+**/
+typedef
+EFI_STATUS
+(EFIAPI *EFI_SERVICE_BINDING_DESTROY_CHILD)(
+  IN EFI_SERVICE_BINDING_PROTOCOL          *This,
+  IN EFI_HANDLE                            ChildHandle
+  );
+
+///
+/// The EFI_SERVICE_BINDING_PROTOCOL provides member functions to create and destroy
+/// child handles. A driver is responsible for adding protocols to the child handle
+/// in CreateChild() and removing protocols in DestroyChild(). It is also required
+/// that the CreateChild() function opens the parent protocol BY_CHILD_CONTROLLER
+/// to establish the parent-child relationship, and closes the protocol in DestroyChild().
+/// The pseudo code for CreateChild() and DestroyChild() is provided to specify the
+/// required behavior, not to specify the required implementation. Each consumer of
+/// a software protocol is responsible for calling CreateChild() when it requires the
+/// protocol and calling DestroyChild() when it is finished with that protocol.
+///
+struct _EFI_SERVICE_BINDING_PROTOCOL {
+  EFI_SERVICE_BINDING_CREATE_CHILD     CreateChild;
+  EFI_SERVICE_BINDING_DESTROY_CHILD    DestroyChild;
+};
+
+#endif

src/include/ipxe/efi/efi_service.h

@@ -0,0 +1,19 @@
+#ifndef _IPXE_EFI_SERVICE_H
+#define _IPXE_EFI_SERVICE_H
+
+/** @file
+ *
+ * EFI service binding
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/efi/efi.h>
+
+extern int efi_service_add ( EFI_HANDLE service, EFI_GUID *binding,
+			     EFI_HANDLE *handle );
+extern int efi_service_del ( EFI_HANDLE service, EFI_GUID *binding,
+			     EFI_HANDLE handle );
+
+#endif /* _IPXE_EFI_SERVICE_H */

src/include/ipxe/errfile.h

@@ -82,6 +82,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ERRFILE_uuid		       ( ERRFILE_CORE | 0x002a0000 )
 #define ERRFILE_efi_path	       ( ERRFILE_CORE | 0x002b0000 )
 #define ERRFILE_efi_mp		       ( ERRFILE_CORE | 0x002c0000 )
+#define ERRFILE_efi_service	       ( ERRFILE_CORE | 0x002d0000 )
 
 #define ERRFILE_eisa		     ( ERRFILE_DRIVER | 0x00000000 )
 #define ERRFILE_isa		     ( ERRFILE_DRIVER | 0x00010000 )