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author | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
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committer | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
commit | 871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch) | |
tree | 8718f573808810c2a1e8cb8fb6ac469093ca2784 /arch/mn10300/kernel/time.c | |
parent | 9d40ac5867b9aefe0722bc1f110b965ff294d30d (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')
-rw-r--r-- | arch/mn10300/kernel/time.c | 124 |
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(); +} |