Index: sys/compat/linuxkpi/common/include/linux/ioport.h
===================================================================
--- /dev/null
+++ sys/compat/linuxkpi/common/include/linux/ioport.h
@@ -0,0 +1,50 @@
+/*-
+ * Copyright (c) 2019 Jonathan Gray
+ * Copyright (c) 2021 Neel Chauhan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice unmodified, this list of conditions, and the following
+ *    disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _LINUX_IOPORT_H
+#define _LINUX_IOPORT_H
+
+#include <sys/types.h>
+
+struct resource {
+	u_long	start;
+	u_long	end;
+};
+
+static inline resource_size_t
+resource_size(const struct resource *r)
+{
+	return r->end - r->start + 1;
+}
+
+#define DEFINE_RES_MEM(_start, _size)		\
+	{					\
+		.start = (_start),		\
+		.end = (_start) + (_size) - 1,	\
+	}
+
+#endif