arch/mips/cpu/mips64/time.c

   1 /*
   2  * (C) Copyright 2003
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <asm/mipsregs.h>
  10
  11 static unsigned long timestamp;
  12
  13 /* how many counter cycles in a jiffy */
  14 #define CYCLES_PER_JIFFY         \
  15         (CONFIG_SYS_MIPS_TIMER_FREQ + CONFIG_SYS_HZ / 2) / CONFIG_SYS_HZ
  16
  17 /*
  18  * timer without interrupts
  19  */
  20
  21 int timer_init(void)
  22 {
  23         /* Set up the timer for the first expiration. */
  24         write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
  25
  26         return 0;
  27 }
  28
  29 ulong get_timer(ulong base)
  30 {
  31         unsigned int count;
  32         unsigned int expirelo = read_c0_compare();
  33
  34         /* Check to see if we have missed any timestamps. */
  35         count = read_c0_count();
  36         while ((count - expirelo) < 0x7fffffff) {
  37                 expirelo += CYCLES_PER_JIFFY;
  38                 timestamp++;
  39         }
  40         write_c0_compare(expirelo);
  41
  42         return timestamp - base;
  43 }
  44
  45 void __udelay(unsigned long usec)
  46 {
  47         unsigned int tmo;
  48
  49         tmo = read_c0_count() + (usec * (CONFIG_SYS_MIPS_TIMER_FREQ / 1000000));
  50         while ((tmo - read_c0_count()) < 0x7fffffff)
  51                 /*NOP*/;
  52 }
  53
  54 /*
  55  * This function is derived from PowerPC code (read timebase as long long).
  56  * On MIPS it just returns the timer value.
  57  */
  58 unsigned long long get_ticks(void)
  59 {
  60         return get_timer(0);
  61 }
  62
  63 /*
  64  * This function is derived from PowerPC code (timebase clock frequency).
  65  * On MIPS it returns the number of timer ticks per second.
  66  */
  67 ulong get_tbclk(void)
  68 {
  69         return CONFIG_SYS_HZ;
  70 }