metag: Time keeping

Add time keeping code for metag. Meta hardware threads have 2 timers.
The background timer (TXTIMER) is used as a free-running time base, and
the interrupt timer (TXTIMERI) is used for the timer interrupt. Both
counters traditionally count at approximately 1MHz.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 68 insertions, 0 deletions

diff --git a/arch/metag/kernel/clock.c b/arch/metag/kernel/clock.c
new file mode 100644
index 000000000000..defc84056f18
--- /dev/null
+++ b/arch/metag/kernel/clock.c
@@ -0,0 +1,53 @@
+/*
+ * arch/metag/kernel/clock.c
+ *
+ * Copyright (C) 2012 Imagination Technologies Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+
+#include <asm/param.h>
+#include <asm/clock.h>
+
+struct meta_clock_desc _meta_clock;
+
+/* Default machine get_core_freq callback. */
+static unsigned long get_core_freq_default(void)
+{
+#ifdef CONFIG_METAG_META21
+	/*
+	 * Meta 2 cores divide down the core clock for the Meta timers, so we
+	 * can estimate the core clock from the divider.
+	 */
+	return (metag_in32(EXPAND_TIMER_DIV) + 1) * 1000000;
+#else
+	/*
+	 * On Meta 1 we don't know the core clock, but assuming the Meta timer
+	 * is correct it can be estimated based on loops_per_jiffy.
+	 */
+	return (loops_per_jiffy * HZ * 5) >> 1;
+#endif
+}
+
+/**
+ * setup_meta_clocks() - Set up the Meta clock.
+ * @desc:	Clock descriptor usually provided by machine description
+ *
+ * Ensures all callbacks are valid.
+ */
+void __init setup_meta_clocks(struct meta_clock_desc *desc)
+{
+	/* copy callbacks */
+	if (desc)
+		_meta_clock = *desc;
+
+	/* set fallback functions */
+	if (!_meta_clock.get_core_freq)
+		_meta_clock.get_core_freq = get_core_freq_default;
+}
+
diff --git a/arch/metag/kernel/time.c b/arch/metag/kernel/time.c
new file mode 100644
index 000000000000..17dc10733b2f
--- /dev/null
+++ b/arch/metag/kernel/time.c
@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) 2005-2013 Imagination Technologies Ltd.
+ *
+ * This file contains the Meta-specific time handling details.
+ *
+ */
+
+#include <linux/init.h>
+
+#include <clocksource/metag_generic.h>
+
+void __init time_init(void)
+{
+	metag_generic_timer_init();
+}