[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>

4 files changed, 248 insertions, 0 deletions

diff --git a/src/include/ipxe/efi/Protocol/ServiceBinding.h b/src/include/ipxe/efi/Protocol/ServiceBinding.h
new file mode 100644
index 00000000..6baf73aa
--- /dev/null
+++ b/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
diff --git a/src/include/ipxe/efi/efi_service.h b/src/include/ipxe/efi/efi_service.h
new file mode 100644
index 00000000..ca4c7b2a
--- /dev/null
+++ b/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 */
diff --git a/src/include/ipxe/errfile.h b/src/include/ipxe/errfile.h
index c673b9a4..083c77e1 100644
--- a/src/include/ipxe/errfile.h
+++ b/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 )
diff --git a/src/interface/efi/efi_service.c b/src/interface/efi/efi_service.c
new file mode 100644
index 00000000..d4129c0d
--- /dev/null
+++ b/src/interface/efi/efi_service.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2024 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * EFI service binding
+ *
+ */
+
+#include <string.h>
+#include <errno.h>
+#include <ipxe/efi/efi.h>
+#include <ipxe/efi/efi_service.h>
+#include <ipxe/efi/Protocol/ServiceBinding.h>
+
+/**
+ * Add service to child handle
+ *
+ * @v service		Service binding handle
+ * @v binding		Service binding protocol GUID
+ * @v handle		Handle on which to install child
+ * @ret rc		Return status code
+ */
+int efi_service_add ( EFI_HANDLE service, EFI_GUID *binding,
+		      EFI_HANDLE *handle ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	union {
+		EFI_SERVICE_BINDING_PROTOCOL *sb;
+		void *interface;
+	} u;
+	EFI_STATUS efirc;
+	int rc;
+
+	/* Open service binding protocol */
+	if ( ( efirc = bs->OpenProtocol ( service, binding, &u.interface,
+					  efi_image_handle, service,
+					  EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
+		rc = -EEFI ( efirc );
+		DBGC ( service, "EFISVC %s cannot open %s binding: %s\n",
+		       efi_handle_name ( service ), efi_guid_ntoa ( binding ),
+		       strerror ( rc ) );
+		goto err_open;
+	}
+
+	/* Create child handle */
+	if ( ( efirc = u.sb->CreateChild ( u.sb, handle ) ) != 0 ) {
+		rc = -EEFI ( efirc );
+		DBGC ( service, "EFISVC %s could not create %s child: %s\n",
+		       efi_handle_name ( service ), efi_guid_ntoa ( binding ),
+		       strerror ( rc ) );
+		goto err_create;
+	}
+
+	/* Success */
+	rc = 0;
+	DBGC ( service, "EFISVC %s created %s child ",
+	       efi_handle_name ( service ), efi_guid_ntoa ( binding ) );
+	DBGC ( service, "%s\n", efi_handle_name ( *handle ) );
+
+ err_create:
+	bs->CloseProtocol ( service, binding, efi_image_handle, service );
+ err_open:
+	return rc;
+}
+
+/**
+ * Remove service from child handle
+ *
+ * @v service		Service binding handle
+ * @v binding		Service binding protocol GUID
+ * @v handle		Child handle
+ * @ret rc		Return status code
+ */
+int efi_service_del ( EFI_HANDLE service, EFI_GUID *binding,
+		      EFI_HANDLE handle ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	union {
+		EFI_SERVICE_BINDING_PROTOCOL *sb;
+		void *interface;
+	} u;
+	EFI_STATUS efirc;
+	int rc;
+
+	DBGC ( service, "EFISVC %s removing %s child ",
+	       efi_handle_name ( service ), efi_guid_ntoa ( binding ) );
+	DBGC ( service, "%s\n", efi_handle_name ( handle ) );
+
+	/* Open service binding protocol */
+	if ( ( efirc = bs->OpenProtocol ( service, binding, &u.interface,
+					  efi_image_handle, service,
+					  EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
+		rc = -EEFI ( efirc );
+		DBGC ( service, "EFISVC %s cannot open %s binding: %s\n",
+		       efi_handle_name ( service ), efi_guid_ntoa ( binding ),
+		       strerror ( rc ) );
+		goto err_open;
+	}
+
+	/* Destroy child handle */
+	if ( ( efirc = u.sb->DestroyChild ( u.sb, handle ) ) != 0 ) {
+		rc = -EEFI ( efirc );
+		DBGC ( service, "EFISVC %s could not destroy %s child ",
+		       efi_handle_name ( service ), efi_guid_ntoa ( binding ) );
+		DBGC ( service, "%s: %s\n",
+		       efi_handle_name ( handle ), strerror ( rc ) );
+		goto err_destroy;
+	}
+
+	/* Success */
+	rc = 0;
+
+ err_destroy:
+	bs->CloseProtocol ( service, binding, efi_image_handle, service );
+ err_open:
+	return rc;
+}