arm64/kernel/time.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Based on arch/arm/kernel/time.c
0004  *
0005  * Copyright (C) 1991, 1992, 1995  Linus Torvalds
0006  * Modifications for ARM (C) 1994-2001 Russell King
0007  * Copyright (C) 2012 ARM Ltd.
0008  */
0009
0010 #include <linux/clockchips.h>
0011 #include <linux/export.h>
0012 #include <linux/kernel.h>
0013 #include <linux/interrupt.h>
0014 #include <linux/time.h>
0015 #include <linux/init.h>
0016 #include <linux/sched.h>
0017 #include <linux/smp.h>
0018 #include <linux/timex.h>
0019 #include <linux/errno.h>
0020 #include <linux/profile.h>
0021 #include <linux/stacktrace.h>
0022 #include <linux/syscore_ops.h>
0023 #include <linux/timer.h>
0024 #include <linux/irq.h>
0025 #include <linux/delay.h>
0026 #include <linux/clocksource.h>
0027 #include <linux/of_clk.h>
0028 #include <linux/acpi.h>
0029
0030 #include <clocksource/arm_arch_timer.h>
0031
0032 #include <asm/thread_info.h>
0033 #include <asm/paravirt.h>
0034
0035 static bool profile_pc_cb(void *arg, unsigned long pc)
0036 {
0037     unsigned long *prof_pc = arg;
0038
0039     if (in_lock_functions(pc))
0040         return true;
0041     *prof_pc = pc;
0042     return false;
0043 }
0044
0045 unsigned long profile_pc(struct pt_regs *regs)
0046 {
0047     unsigned long prof_pc = 0;
0048
0049     arch_stack_walk(profile_pc_cb, &prof_pc, current, regs);
0050
0051     return prof_pc;
0052 }
0053 EXPORT_SYMBOL(profile_pc);
0054
0055 void __init time_init(void)
0056 {
0057     u32 arch_timer_rate;
0058
0059     of_clk_init(NULL);
0060     timer_probe();
0061
0062     tick_setup_hrtimer_broadcast();
0063
0064     arch_timer_rate = arch_timer_get_rate();
0065     if (!arch_timer_rate)
0066         panic("Unable to initialise architected timer.\n");
0067
0068     /* Calibrate the delay loop directly */
0069     lpj_fine = arch_timer_rate / HZ;
0070
0071     pv_time_init();
0072 }