arch/riscv/kernel/time.c

   1 /*
   2  * Copyright (C) 2012 Regents of the University of California
   3  * Copyright (C) 2017 SiFive
   4  *
   5  *   This program is free software; you can redistribute it and/or
   6  *   modify it under the terms of the GNU General Public License
   7  *   as published by the Free Software Foundation, version 2.
   8  *
   9  *   This program is distributed in the hope that it will be useful,
  10  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *   GNU General Public License for more details.
  13  */
  14
  15 #include <linux/clocksource.h>
  16 #include <linux/delay.h>
  17 #include <asm/sbi.h>
  18
  19 unsigned long riscv_timebase;
  20
  21 void __init time_init(void)
  22 {
  23         struct device_node *cpu;
  24         u32 prop;
  25
  26         cpu = of_find_node_by_path("/cpus");
  27         if (!cpu || of_property_read_u32(cpu, "timebase-frequency", &prop))
  28                 panic(KERN_WARNING "RISC-V system with no 'timebase-frequency' in DTS\n");
  29         riscv_timebase = prop;
  30
  31         lpj_fine = riscv_timebase / HZ;
  32         timer_probe();
  33 }