1 files changed, 82 insertions, 0 deletions
diff --git a/sys/arch/amd64/stand/libsa/gateA20.c b/sys/arch/amd64/stand/libsa/gateA20.c
new file mode 100644
index 00000000000..26cfb3539cb
--- /dev/null
+++ b/sys/arch/amd64/stand/libsa/gateA20.c
@@ -0,0 +1,82 @@
+/*	$OpenBSD: gateA20.c,v 1.1 2004/02/03 12:09:47 mickey Exp $	*/
+
+/*
+ * Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
+ *
+ * Mach Operating System
+ * Copyright (c) 1992, 1991 Carnegie Mellon University
+ * All Rights Reserved.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie Mellon
+ * the rights to redistribute these changes.
+ */
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <machine/pio.h>
+#include <dev/ic/i8042reg.h>
+#include <dev/isa/isareg.h>
+
+#include "libsa.h"
+
+#define KB_A20		0xdf		/* enable A20,
+					   enable output buffer full interrupt
+					   enable data line
+					   enable clock line */
+
+
+/*
+ * Gate A20 for high memory
+ */
+void
+gateA20(int on)
+{
+	if (ps2model == 0xf82 ||
+	    (inb(IO_KBD + KBSTATP) == 0xff && inb(IO_KBD + KBDATAP) == 0xff)) {
+		int data;
+
+		/* Try to use 0x92 to turn on A20 */
+		if (on) {
+			data = inb(0x92);
+			outb(0x92, data | 0x2);
+		} else {
+			data = inb(0x92);
+			outb(0x92, data & ~0x2);
+		}
+	} else {
+
+		while (inb(IO_KBD + KBSTATP) & KBS_IBF);
+
+		while (inb(IO_KBD + KBSTATP) & KBS_DIB)
+			(void)inb(IO_KBD + KBDATAP);
+
+		outb(IO_KBD + KBCMDP, KBC_CMDWOUT);
+		while (inb(IO_KBD + KBSTATP) & KBS_IBF);
+
+		if (on)
+			outb(IO_KBD + KBDATAP, KB_A20);
+		else
+			outb(IO_KBD + KBDATAP, 0xcd);
+		while (inb(IO_KBD + KBSTATP) & KBS_IBF);
+
+		while (inb(IO_KBD + KBSTATP) & KBS_DIB)
+			(void)inb(IO_KBD + KBDATAP);
+	}
+}