1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *  linux/arch/arm/kernel/time.c
4 *
5 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
6 *  Modifications for ARM (C) 1994-2001 Russell King
7 *
8 *  This file contains the ARM-specific time handling details:
9 *  reading the RTC at bootup, etc...
10 */
11#include <linux/clockchips.h>
12#include <linux/clocksource.h>
13#include <linux/errno.h>
14#include <linux/export.h>
15#include <linux/init.h>
16#include <linux/interrupt.h>
17#include <linux/irq.h>
18#include <linux/kernel.h>
19#include <linux/of_clk.h>
20#include <linux/profile.h>
21#include <linux/sched.h>
22#include <linux/sched_clock.h>
23#include <linux/smp.h>
24#include <linux/time.h>
25#include <linux/timex.h>
26#include <linux/timer.h>
27
28#include <asm/mach/arch.h>
29#include <asm/mach/time.h>
30#include <asm/stacktrace.h>
31#include <asm/thread_info.h>
32
33#if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || \
34    defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE)
35/* this needs a better home */
36DEFINE_SPINLOCK(rtc_lock);
37EXPORT_SYMBOL(rtc_lock);
38#endif	/* pc-style 'CMOS' RTC support */
39
40/* change this if you have some constant time drift */
41#define USECS_PER_JIFFY	(1000000/HZ)
42
43#ifdef CONFIG_SMP
44unsigned long profile_pc(struct pt_regs *regs)
45{
46	struct stackframe frame;
47
48	if (!in_lock_functions(regs->ARM_pc))
49		return regs->ARM_pc;
50
51	arm_get_current_stackframe(regs, &frame);
52	do {
53		int ret = unwind_frame(&frame);
54		if (ret < 0)
55			return 0;
56	} while (in_lock_functions(frame.pc));
57
58	return frame.pc;
59}
60EXPORT_SYMBOL(profile_pc);
61#endif
62
63static void dummy_clock_access(struct timespec64 *ts)
64{
65	ts->tv_sec = 0;
66	ts->tv_nsec = 0;
67}
68
69static clock_access_fn __read_persistent_clock = dummy_clock_access;
70
71void read_persistent_clock64(struct timespec64 *ts)
72{
73	__read_persistent_clock(ts);
74}
75
76int __init register_persistent_clock(clock_access_fn read_persistent)
77{
78	/* Only allow the clockaccess functions to be registered once */
79	if (__read_persistent_clock == dummy_clock_access) {
80		if (read_persistent)
81			__read_persistent_clock = read_persistent;
82		return 0;
83	}
84
85	return -EINVAL;
86}
87
88void __init time_init(void)
89{
90	if (machine_desc->init_time) {
91		machine_desc->init_time();
92	} else {
93#ifdef CONFIG_COMMON_CLK
94		of_clk_init(NULL);
95#endif
96		timer_probe();
97		tick_setup_hrtimer_broadcast();
98	}
99}
100