arch/mips/cpu/mips32/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        (CONFIG_SYS_MIPS_TIMER_FREQ + CONFIG_SYS_HZ / 2) / CONFIG_SYS_HZ
  15
  16 /*
  17  * timer without interrupts
  18  */
  19
  20 int timer_init(void)
  21 {
  22         /* Set up the timer for the first expiration. */
  23         write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
  24
  25         return 0;
  26 }
  27
  28 ulong get_timer(ulong base)
  29 {
  30         unsigned int count;
  31         unsigned int expirelo = read_c0_compare();
  32
  33         /* Check to see if we have missed any timestamps. */
  34         count = read_c0_count();
  35         while ((count - expirelo) < 0x7fffffff) {
  36                 expirelo += CYCLES_PER_JIFFY;
  37                 timestamp++;
  38         }
  39         write_c0_compare(expirelo);
  40
  41         return (timestamp - base);
  42 }
  43
  44 void __udelay(unsigned long usec)
  45 {
  46         unsigned int tmo;
  47
  48         tmo = read_c0_count() + (usec * (CONFIG_SYS_MIPS_TIMER_FREQ / 1000000));
  49         while ((tmo - read_c0_count()) < 0x7fffffff)
  50                 /*NOP*/;
  51 }
  52
  53 /*
  54  * This function is derived from PowerPC code (read timebase as long long).
  55  * On MIPS it just returns the timer value.
  56  */
  57 unsigned long long get_ticks(void)
  58 {
  59         return get_timer(0);
  60 }
  61
  62 /*
  63  * This function is derived from PowerPC code (timebase clock frequency).
  64  * On MIPS it returns the number of timer ticks per second.
  65  */
  66 ulong get_tbclk(void)
  67 {
  68         return CONFIG_SYS_HZ;
  69 }