arch/arm/kernel/arch_timer.c

   1 /*
   2  *  linux/arch/arm/kernel/arch_timer.c
   3  *
   4  *  Copyright (C) 2011 ARM Ltd.
   5  *  All Rights Reserved
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/init.h>
  12 #include <linux/types.h>
  13
  14 #include <asm/delay.h>
  15 #include <asm/sched_clock.h>
  16
  17 #include <clocksource/arm_arch_timer.h>
  18
  19 static unsigned long arch_timer_read_counter_long(void)
  20 {
  21         return arch_timer_read_counter();
  22 }
  23
  24 static u32 arch_timer_read_counter_u32(void)
  25 {
  26         return arch_timer_read_counter();
  27 }
  28
  29 static struct delay_timer arch_delay_timer;
  30
  31 static void __init arch_timer_delay_timer_register(void)
  32 {
  33         /* Use the architected timer for the delay loop. */
  34         arch_delay_timer.read_current_timer = arch_timer_read_counter_long;
  35         arch_delay_timer.freq = arch_timer_get_rate();
  36         register_current_timer_delay(&arch_delay_timer);
  37 }
  38
  39 int __init arch_timer_of_register(void)
  40 {
  41         int ret;
  42
  43         ret = arch_timer_init();
  44         if (ret)
  45                 return ret;
  46
  47         arch_timer_delay_timer_register();
  48
  49         return 0;
  50 }
  51
  52 int __init arch_timer_sched_clock_init(void)
  53 {
  54         if (arch_timer_get_rate() == 0)
  55                 return -ENXIO;
  56
  57         setup_sched_clock(arch_timer_read_counter_u32,
  58                           32, arch_timer_get_rate());
  59         return 0;
  60 }