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authorSrikant Patnaik2015-01-11 12:28:04 +0530
committerSrikant Patnaik2015-01-11 12:28:04 +0530
commit871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch)
tree8718f573808810c2a1e8cb8fb6ac469093ca2784 /arch/mn10300/kernel/time.c
parent9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff)
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Moved, renamed, and deleted files
The original directory structure was scattered and unorganized. Changes are basically to make it look like kernel structure.
Diffstat (limited to 'arch/mn10300/kernel/time.c')
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1 files changed, 124 insertions, 0 deletions
diff --git a/arch/mn10300/kernel/time.c b/arch/mn10300/kernel/time.c
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+/* 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();
+}