1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Based on arch/arm/kernel/time.c
4 *
5 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
6 * Modifications for ARM (C) 1994-2001 Russell King
7 * Copyright (C) 2012 ARM Ltd.
8 */
9
10#include <linux/clockchips.h>
11#include <linux/export.h>
12#include <linux/kernel.h>
13#include <linux/interrupt.h>
14#include <linux/time.h>
15#include <linux/init.h>
16#include <linux/sched.h>
17#include <linux/smp.h>
18#include <linux/timex.h>
19#include <linux/errno.h>
20#include <linux/profile.h>
21#include <linux/stacktrace.h>
22#include <linux/syscore_ops.h>
23#include <linux/timer.h>
24#include <linux/irq.h>
25#include <linux/delay.h>
26#include <linux/clocksource.h>
27#include <linux/of_clk.h>
28#include <linux/acpi.h>
29
30#include <clocksource/arm_arch_timer.h>
31
32#include <asm/thread_info.h>
33#include <asm/paravirt.h>
34
35static bool profile_pc_cb(void *arg, unsigned long pc)
36{
37 unsigned long *prof_pc = arg;
38
39 if (in_lock_functions(addr: pc))
40 return true;
41 *prof_pc = pc;
42 return false;
43}
44
45unsigned long profile_pc(struct pt_regs *regs)
46{
47 unsigned long prof_pc = 0;
48
49 arch_stack_walk(consume_entry: profile_pc_cb, cookie: &prof_pc, current, regs);
50
51 return prof_pc;
52}
53EXPORT_SYMBOL(profile_pc);
54
55void __init time_init(void)
56{
57 u32 arch_timer_rate;
58
59 of_clk_init(NULL);
60 timer_probe();
61
62 tick_setup_hrtimer_broadcast();
63
64 arch_timer_rate = arch_timer_get_rate();
65 if (!arch_timer_rate)
66 panic(fmt: "Unable to initialise architected timer.\n");
67
68 /* Calibrate the delay loop directly */
69 lpj_fine = arch_timer_rate / HZ;
70
71 pv_time_init();
72}
73

source code of linux/arch/arm64/kernel/time.c