arch/arm/kernel/arch_timer.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/arch/arm/kernel/arch_timer.c
   4  *
   5  *  Copyright (C) 2011 ARM Ltd.
   6  *  All Rights Reserved
   7  */
   8 #include <linux/init.h>
   9 #include <linux/types.h>
  10 #include <linux/errno.h>
  11
  12 #include <asm/delay.h>
  13
  14 #include <clocksource/arm_arch_timer.h>
  15
  16 static unsigned long arch_timer_read_counter_long(void)
  17 {
  18         return arch_timer_read_counter();
  19 }
  20
  21 static struct delay_timer arch_delay_timer;
  22
  23 static void __init arch_timer_delay_timer_register(void)
  24 {
  25         /* Use the architected timer for the delay loop. */
  26         arch_delay_timer.read_current_timer = arch_timer_read_counter_long;
  27         arch_delay_timer.freq = arch_timer_get_rate();
  28         register_current_timer_delay(&arch_delay_timer);
  29 }
  30
  31 int __init arch_timer_arch_init(void)
  32 {
  33         u32 arch_timer_rate = arch_timer_get_rate();
  34
  35         if (arch_timer_rate == 0)
  36                 return -ENXIO;
  37
  38         arch_timer_delay_timer_register();
  39
  40         return 0;
  41 }