arch/arm64/kernel/time.c

   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
  35 static bool profile_pc_cb(void *arg, unsigned long pc)
  36 {
  37         unsigned long *prof_pc = arg;
  38
  39         if (in_lock_functions(pc))
  40                 return true;
  41         *prof_pc = pc;
  42         return false;
  43 }
  44
  45 unsigned long profile_pc(struct pt_regs *regs)
  46 {
  47         unsigned long prof_pc = 0;
  48
  49         arch_stack_walk(profile_pc_cb, &prof_pc, current, regs);
  50
  51         return prof_pc;
  52 }
  53 EXPORT_SYMBOL(profile_pc);
  54
  55 void __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("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 }