OpenRISC: Timekeeping

Implements support for the OpenRISC timer which is a 28 bit cycle counter
that can be read out of a special purpose register.  This counter is
used as a both a clock event and clocksource device.

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Cc: tglx@linutronix.de
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

arch/openrisc/include/asm/timex.h

@@ -0,0 +1,36 @@
+/*
+ * OpenRISC Linux
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others.  All original copyrights apply as per the original source
+ * declaration.
+ *
+ * OpenRISC implementation:
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ *
+ * 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.
+ */
+
+#ifndef __ASM_OPENRISC_TIMEX_H
+#define __ASM_OPENRISC_TIMEX_H
+
+#define get_cycles get_cycles
+
+#include <asm-generic/timex.h>
+#include <asm/spr.h>
+#include <asm/spr_defs.h>
+
+static inline cycles_t get_cycles(void)
+{
+	return mfspr(SPR_TTCR);
+}
+
+/* This isn't really used any more */
+#define CLOCK_TICK_RATE 1000
+
+#define ARCH_HAS_READ_CURRENT_TIMER
+
+#endif