1 files changed, 54 insertions, 0 deletions

diff --git a/include/asm-mips/timex.h b/include/asm-mips/timex.h
new file mode 100644
index 000000000000..98aa737b34aa
--- /dev/null
+++ b/include/asm-mips/timex.h
@@ -0,0 +1,54 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1998, 1999, 2003 by Ralf Baechle
+ */
+#ifndef _ASM_TIMEX_H
+#define _ASM_TIMEX_H
+
+#include <asm/mipsregs.h>
+
+/*
+ * This is the frequency of the timer used for Linux's timer interrupt.
+ * The value should be defined as accurate as possible or under certain
+ * circumstances Linux timekeeping might become inaccurate or fail.
+ *
+ * For many system the exact clockrate of the timer isn't known but due to
+ * the way this value is used we can get away with a wrong value as long
+ * as this value is:
+ *
+ *  - a multiple of HZ
+ *  - a divisor of the actual rate
+ *
+ * 500000 is a good such cheat value.
+ *
+ * The obscure number 1193182 is the same as used by the original i8254
+ * time in legacy PC hardware; the chip unfortunately also found in a
+ * bunch of MIPS systems.  The last remaining user of the i8254 for the
+ * timer interrupt is the RM200; it's a very standard system so there is
+ * no reason to make this a separate architecture.
+ */
+
+#include <timex.h>
+
+/*
+ * Standard way to access the cycle counter.
+ * Currently only used on SMP for scheduling.
+ *
+ * Only the low 32 bits are available as a continuously counting entity.
+ * But this only means we'll force a reschedule every 8 seconds or so,
+ * which isn't an evil thing.
+ *
+ * We know that all SMP capable CPUs have cycle counters.
+ */
+
+typedef unsigned int cycles_t;
+
+static inline cycles_t get_cycles (void)
+{
+        return read_c0_count();
+}
+
+#endif /*  _ASM_TIMEX_H */