diff --git a/sys/dev/mscp/mscpreg.h b/sys/dev/mscp/mscpreg.h
new file mode 100644
index 000000000000..431498a02859
--- /dev/null
+++ b/sys/dev/mscp/mscpreg.h
@@ -0,0 +1,125 @@
+/*	$NetBSD: mscpreg.h,v 1.4 1999/05/29 19:12:53 ragge Exp $	*/
+/*
+ * Copyright (c) 1996 Ludd, University of Lule}, Sweden.
+ * Copyright (c) 1988 Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * 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, 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
+ *
+ *	@(#)udareg.h	7.3 (Berkeley) 5/8/91
+ */
+
+/*
+ * NRSPL2 and NCMDL2 control the number of response and command
+ * packets respectively.  They may be any value from 0 to 7, though
+ * setting them higher than 5 is unlikely to be of any value.
+ * If you get warnings about your command ring being too small,
+ * try increasing the values by one.
+ */
+#ifndef NRSP
+#define NRSPL2	5
+#define NCMDL2	5
+#define NRSP	(1 << NRSPL2)
+#define NCMD	(1 << NCMDL2)
+#endif
+
+/*
+ * Communication area definition. This seems to be the same for
+ * all types of MSCP controllers.
+ */
+
+struct mscp_ca {
+	short	ca_xxx1;	/* unused */
+	char	ca_xxx2;	/* unused */
+	char	ca_bdp;		/* BDP to purge */
+	short	ca_cmdint;	/* command ring transition flag */
+	short	ca_rspint;	/* response ring transition flag */
+	long	ca_rspdsc[NRSP];/* response descriptors */
+	long	ca_cmddsc[NCMD];/* command descriptors */
+};
+
+/*
+ * Simplified routines (e.g., uddump) reprogram the UDA50 for one command
+ * and one response at a time; uda1ca is like udaca except that it provides
+ * exactly one command and response descriptor.
+ */
+struct mscp_1ca {
+	short	ca_xxx1;
+	char	ca_xxx2;
+	char	ca_bdp;
+	short	ca_cmdint;
+	short	ca_rspint;
+	long	ca_rspdsc;
+	long	ca_cmddsc;
+};
+
+/*
+ * Combined communications area and MSCP packet pools, per controller.
+ * NRSP and NCMD must be defined before this struct is used.
+ */
+
+struct	mscp_pack {
+	struct	mscp_ca mp_ca;		/* communications area */
+	struct	mscp mp_rsp[NRSP];	/* response packets */
+	struct	mscp mp_cmd[NCMD];	/* command packets */
+};
+
+/*
+ * Bits in UDA status register during initialisation
+ */
+#define MP_ERR		0x8000	/* error */
+#define MP_STEP4	0x4000	/* step 4 has started */
+#define MP_STEP3	0x2000	/* step 3 has started */
+#define MP_STEP2	0x1000	/* step 2 has started */
+#define MP_STEP1	0x0800	/* step 1 has started */
+#define MP_NV		0x0400	/* no host settable interrupt vector */
+#define MP_QB		0x0200	/* controller supports Q22 bus */
+#define MP_DI		0x0100	/* controller implements diagnostics */
+#define MP_IE		0x0080	/* interrupt enable */
+#define MP_NCNRMASK	0x003f	/* in STEP1, bits 0-2=NCMDL2, 3-5=NRSPL2 */
+#define MP_IVECMASK	0x007f	/* in STEP2, bits 0-6 are interruptvec / 4 */
+#define MP_PI		0x0001	/* host requests adapter purge interrupts */
+#define MP_GO		0x0001	/* Go command to ctlr */
+
+#define ALLSTEPS	(MP_ERR | MP_STEP4 | MP_STEP3 | MP_STEP2 | MP_STEP1)
+
+#define STEP0MASK	(ALLSTEPS | MP_NV)
+
+#define STEP1MASK	(ALLSTEPS | MP_IE | MP_NCNRMASK) 
+#define STEP1GOOD	(MP_STEP2 | MP_IE | (NCMDL2 << 3) | NRSPL2)
+ 
+#define STEP2MASK	(ALLSTEPS | MP_IE | MP_IVECMASK)
+#define STEP2GOOD(iv)	(MP_STEP3 | MP_IE | (iv))
+ 
+#define STEP3MASK	ALLSTEPS
+#define STEP3GOOD	MP_STEP4
+