swh:1:snp:32555a3fd8878f019c2ebd6c964bc1edcaeff337
Tip revision: 16fbf79b0f83bc752cee8589279f1ebfe57b3b6e authored by Linus Torvalds on 23 March 2020, 01:31:56 UTC
Linux 5.6-rc7
Linux 5.6-rc7
Tip revision: 16fbf79
time.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/arch/arm/kernel/time.c
*
* Copyright (C) 1991, 1992, 1995 Linus Torvalds
* Modifications for ARM (C) 1994-2001 Russell King
*
* This file contains the ARM-specific time handling details:
* reading the RTC at bootup, etc...
*/
#include <linux/clk-provider.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/profile.h>
#include <linux/sched.h>
#include <linux/sched_clock.h>
#include <linux/smp.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/timer.h>
#include <asm/mach/arch.h>
#include <asm/mach/time.h>
#include <asm/stacktrace.h>
#include <asm/thread_info.h>
#if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || \
defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE)
/* this needs a better home */
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
#endif /* pc-style 'CMOS' RTC support */
/* change this if you have some constant time drift */
#define USECS_PER_JIFFY (1000000/HZ)
#ifdef CONFIG_SMP
unsigned long profile_pc(struct pt_regs *regs)
{
struct stackframe frame;
if (!in_lock_functions(regs->ARM_pc))
return regs->ARM_pc;
arm_get_current_stackframe(regs, &frame);
do {
int ret = unwind_frame(&frame);
if (ret < 0)
return 0;
} while (in_lock_functions(frame.pc));
return frame.pc;
}
EXPORT_SYMBOL(profile_pc);
#endif
#ifndef CONFIG_GENERIC_CLOCKEVENTS
/*
* Kernel system timer support.
*/
void timer_tick(void)
{
profile_tick(CPU_PROFILING);
xtime_update(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(get_irq_regs()));
#endif
}
#endif
static void dummy_clock_access(struct timespec64 *ts)
{
ts->tv_sec = 0;
ts->tv_nsec = 0;
}
static clock_access_fn __read_persistent_clock = dummy_clock_access;
void read_persistent_clock64(struct timespec64 *ts)
{
__read_persistent_clock(ts);
}
int __init register_persistent_clock(clock_access_fn read_persistent)
{
/* Only allow the clockaccess functions to be registered once */
if (__read_persistent_clock == dummy_clock_access) {
if (read_persistent)
__read_persistent_clock = read_persistent;
return 0;
}
return -EINVAL;
}
void __init time_init(void)
{
if (machine_desc->init_time) {
machine_desc->init_time();
} else {
#ifdef CONFIG_COMMON_CLK
of_clk_init(NULL);
#endif
timer_probe();
tick_setup_hrtimer_broadcast();
}
}