board: xen: De-initialize before jumping to Linux

Free resources used by Xen board before jumping to Linux kernel.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/board/xen/xenguest_arm64/xenguest_arm64.c b/board/xen/xenguest_arm64/xenguest_arm64.c
index cd36938..cce5436 100644
--- a/board/xen/xenguest_arm64/xenguest_arm64.c
+++ b/board/xen/xenguest_arm64/xenguest_arm64.c
@@ -12,6 +12,7 @@
 #include <dm.h>
 #include <errno.h>
 #include <malloc.h>
+#include <xen.h>
 
 #include <asm/io.h>
 #include <asm/armv8/mmu.h>
@@ -194,3 +195,8 @@
 	return 0;
 }
 
+void board_cleanup_before_linux(void)
+{
+	xen_fini();
+}
+
diff --git a/drivers/xen/hypervisor.c b/drivers/xen/hypervisor.c
index 58b0865..178c206 100644
--- a/drivers/xen/hypervisor.c
+++ b/drivers/xen/hypervisor.c
@@ -242,3 +242,11 @@
 	init_gnttab();
 }
 
+void xen_fini(void)
+{
+	debug("%s\n", __func__);
+
+	fini_gnttab();
+	fini_xenbus();
+	fini_events();
+}
diff --git a/include/xen.h b/include/xen.h
index 686b714..a952a2c 100644
--- a/include/xen.h
+++ b/include/xen.h
@@ -13,4 +13,12 @@
  */
 void xen_init(void);
 
+/**
+ * xen_fini() - Board cleanup before Linux kernel start
+ *
+ * Unmap Xen memory pages the specified guest's pseudophysical
+ * address space and unbind all event channels.
+ */
+void xen_fini(void);
+
 #endif /* __XEN_H__ */