mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-25 20:14:25 +08:00
dc7daf3362
Use clockevents_calc_mult_shift() instead of the homebrewn function in mn10300/kernel/time.c. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Cc: Mark Salter <msalter@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com>
125 lines
3.3 KiB
C
125 lines
3.3 KiB
C
/* 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();
|
|
}
|