1 files changed, 124 insertions, 0 deletions
diff --git a/arch/mn10300/kernel/time.c b/arch/mn10300/kernel/time.c
new file mode 100644
index 00000000..67c6416a
--- /dev/null
+++ b/arch/mn10300/kernel/time.c
@@ -0,0 +1,124 @@
+/* MN10300 Low level time management
+ *
+ * Copyright (C) 2007-2008 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ * - Derived from arch/i386/kernel/time.c
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/profile.h>
+#include <linux/cnt32_to_63.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <asm/irq.h>
+#include <asm/div64.h>
+#include <asm/processor.h>
+#include <asm/intctl-regs.h>
+#include <asm/rtc.h>
+#include "internal.h"
+
+static unsigned long mn10300_last_tsc;	/* time-stamp counter at last time
+					 * interrupt occurred */
+
+static unsigned long sched_clock_multiplier;
+
+/*
+ * scheduler clock - returns current time in nanosec units.
+ */
+unsigned long long sched_clock(void)
+{
+	union {
+		unsigned long long ll;
+		unsigned l[2];
+	} tsc64, result;
+	unsigned long tmp;
+	unsigned product[3]; /* 96-bit intermediate value */
+
+	/* cnt32_to_63() is not safe with preemption */
+	preempt_disable();
+
+	/* expand the tsc to 64-bits.
+	 * - sched_clock() must be called once a minute or better or the
+	 *   following will go horribly wrong - see cnt32_to_63()
+	 */
+	tsc64.ll = cnt32_to_63(get_cycles()) & 0x7fffffffffffffffULL;
+
+	preempt_enable();
+
+	/* scale the 64-bit TSC value to a nanosecond value via a 96-bit
+	 * intermediate
+	 */
+	asm("mulu	%2,%0,%3,%0	\n"	/* LSW * mult ->  0:%3:%0 */
+	    "mulu	%2,%1,%2,%1	\n"	/* MSW * mult -> %2:%1:0 */
+	    "add	%3,%1		\n"
+	    "addc	0,%2		\n"	/* result in %2:%1:%0 */
+	    : "=r"(product[0]), "=r"(product[1]), "=r"(product[2]), "=r"(tmp)
+	    :  "0"(tsc64.l[0]),  "1"(tsc64.l[1]),  "2"(sched_clock_multiplier)
+	    : "cc");
+
+	result.l[0] = product[1] << 16 | product[0] >> 16;
+	result.l[1] = product[2] << 16 | product[1] >> 16;
+
+	return result.ll;
+}
+
+/*
+ * initialise the scheduler clock
+ */
+static void __init mn10300_sched_clock_init(void)
+{
+	sched_clock_multiplier =
+		__muldiv64u(NSEC_PER_SEC, 1 << 16, MN10300_TSCCLK);
+}
+
+/**
+ * local_timer_interrupt - Local timer interrupt handler
+ *
+ * Handle local timer interrupts for this CPU.  They may have been propagated
+ * to this CPU from the CPU that actually gets them by way of an IPI.
+ */
+irqreturn_t local_timer_interrupt(void)
+{
+	profile_tick(CPU_PROFILING);
+	update_process_times(user_mode(get_irq_regs()));
+	return IRQ_HANDLED;
+}
+
+/*
+ * initialise the various timers used by the main part of the kernel
+ */
+void __init time_init(void)
+{
+	/* we need the prescalar running to be able to use IOCLK/8
+	 * - IOCLK runs at 1/4 (ST5 open) or 1/8 (ST5 closed) internal CPU clock
+	 * - IOCLK runs at Fosc rate (crystal speed)
+	 */
+	TMPSCNT |= TMPSCNT_ENABLE;
+
+	init_clocksource();
+
+	printk(KERN_INFO
+	       "timestamp counter I/O clock running at %lu.%02lu"
+	       " (calibrated against RTC)\n",
+	       MN10300_TSCCLK / 1000000, (MN10300_TSCCLK / 10000) % 100);
+
+	mn10300_last_tsc = read_timestamp_counter();
+
+	init_clockevents();
+
+#ifdef CONFIG_MN10300_WD_TIMER
+	/* start the watchdog timer */
+	watchdog_go();
+#endif
+
+	mn10300_sched_clock_init();
+}