x86 BIOS interface for RTC on SGI UV

Real-time code needs to know the number of cycles per second
on SGI UV.  The information is provided via a run time BIOS
call.  This patch provides the linux side of that interface.
This is the first of several run time BIOS calls to be defined
in uv/bios.h and bios_uv.c.

Note that BIOS_CALL() is just a stub for now.  The bios
side is being worked on.

Signed-off-by: Russ Anderson <rja@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/uv/bios.h b/include/asm-x86/uv/bios.h
new file mode 100644
index 0000000..aa73362
--- /dev/null
+++ b/include/asm-x86/uv/bios.h
@@ -0,0 +1,68 @@
+#ifndef _ASM_X86_BIOS_H
+#define _ASM_X86_BIOS_H
+
+/*
+ * BIOS layer definitions.
+ *
+ *  Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
+ *
+ *  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
+ *  (at your option) 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/rtc.h>
+
+#define BIOS_FREQ_BASE			0x01000001
+
+enum {
+	BIOS_FREQ_BASE_PLATFORM = 0,
+	BIOS_FREQ_BASE_INTERVAL_TIMER = 1,
+	BIOS_FREQ_BASE_REALTIME_CLOCK = 2
+};
+
+# define BIOS_CALL(result, a0, a1, a2, a3, a4, a5, a6, a7)		\
+	do {								\
+		/* XXX - the real call goes here */			\
+		result.status = BIOS_STATUS_UNIMPLEMENTED;		\
+		isrv.v0 = 0;						\
+		isrv.v1 = 0;						\
+	} while (0)
+
+enum {
+	BIOS_STATUS_SUCCESS		=  0,
+	BIOS_STATUS_UNIMPLEMENTED	= -1,
+	BIOS_STATUS_EINVAL		= -2,
+	BIOS_STATUS_ERROR		= -3
+};
+
+struct uv_bios_retval {
+	/*
+	 * A zero status value indicates call completed without error.
+	 * A negative status value indicates reason of call failure.
+	 * A positive status value indicates success but an
+	 * informational value should be printed (e.g., "reboot for
+	 * change to take effect").
+	 */
+	s64 status;
+	u64 v0;
+	u64 v1;
+	u64 v2;
+};
+
+extern long
+x86_bios_freq_base(unsigned long which, unsigned long *ticks_per_second,
+		   unsigned long *drift_info);
+extern const char *x86_bios_strerror(long status);
+
+#endif /* _ASM_X86_BIOS_H */