Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / mn10300 / kernel / time.c

diff --git a/kernel/arch/mn10300/kernel/time.c b/kernel/arch/mn10300/kernel/time.c
new file mode 100644 (file)
index 0000000..67c6416
--- /dev/null
+++ b/kernel/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();
+}