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/syscore_ops.h>
  22 #include <linux/timer.h>
  23 #include <linux/irq.h>
  24 #include <linux/delay.h>
  25 #include <linux/clocksource.h>
  26 #include <linux/clk-provider.h>
  27 #include <linux/acpi.h>
  28
  29 #include <clocksource/arm_arch_timer.h>
  30
  31 #include <asm/thread_info.h>
  32 #include <asm/stacktrace.h>
  33 #include <asm/paravirt.h>
  34
  35 unsigned long profile_pc(struct pt_regs *regs)
  36 {
  37         struct stackframe frame;
  38
  39         if (!in_lock_functions(regs->pc))
  40                 return regs->pc;
  41
  42         start_backtrace(&frame, regs->regs[29], regs->pc);
  43
  44         do {
  45                 int ret = unwind_frame(NULL, &frame);
  46                 if (ret < 0)
  47                         return 0;
  48         } while (in_lock_functions(frame.pc));
  49
  50         return frame.pc;
  51 }
  52 EXPORT_SYMBOL(profile_pc);
  53
  54 void __init time_init(void)
  55 {
  56         u32 arch_timer_rate;
  57
  58         of_clk_init(NULL);
  59         timer_probe();
  60
  61         tick_setup_hrtimer_broadcast();
  62
  63         arch_timer_rate = arch_timer_get_rate();
  64         if (!arch_timer_rate)
  65                 panic("Unable to initialise architected timer.\n");
  66
  67         /* Calibrate the delay loop directly */
  68         lpj_fine = arch_timer_rate / HZ;
  69
  70         pv_time_init();
  71 }