arch/mips/kernel/csrc-r4k.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2007 by Ralf Baechle
   7  */
   8 #include <linux/clocksource.h>
   9 #include <linux/init.h>
  10 #include <linux/sched_clock.h>
  11
  12 #include <asm/time.h>
  13
  14 static cycle_t c0_hpt_read(struct clocksource *cs)
  15 {
  16         return read_c0_count();
  17 }
  18
  19 static struct clocksource clocksource_mips = {
  20         .name           = "MIPS",
  21         .read           = c0_hpt_read,
  22         .mask           = CLOCKSOURCE_MASK(32),
  23         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  24 };
  25
  26 static u64 __maybe_unused notrace r4k_read_sched_clock(void)
  27 {
  28         return read_c0_count();
  29 }
  30
  31 int __init init_r4k_clocksource(void)
  32 {
  33         if (!cpu_has_counter || !mips_hpt_frequency)
  34                 return -ENXIO;
  35
  36         /* Calculate a somewhat reasonable rating value */
  37         clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
  38
  39         clocksource_register_hz(&clocksource_mips, mips_hpt_frequency);
  40
  41 #ifndef CONFIG_CPU_FREQ
  42         sched_clock_register(r4k_read_sched_clock, 32, mips_hpt_frequency);
  43 #endif
  44
  45         return 0;
  46 }