LXR uboot/arch/powerpc/lib/time.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * (C) Copyright 2000, 2001
   4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   5 */
   6
   7#include <common.h>
   8#include <init.h>
   9#include <time.h>
  10#include <asm/io.h>
  11#include <linux/delay.h>
  12
  13/* ------------------------------------------------------------------------- */
  14
  15/*
  16 * This function is intended for SHORT delays only.
  17 * It will overflow at around 10 seconds @ 400MHz,
  18 * or 20 seconds @ 200MHz.
  19 */
  20unsigned long usec2ticks(unsigned long usec)
  21{
  22        ulong ticks;
  23
  24        if (usec < 1000) {
  25                ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
  26        } else {
  27                ticks = ((usec / 10) * (get_tbclk() / 100000));
  28        }
  29
  30        return (ticks);
  31}
  32
  33/* ------------------------------------------------------------------------- */
  34
  35/*
  36 * We implement the delay by converting the delay (the number of
  37 * microseconds to wait) into a number of time base ticks; then we
  38 * watch the time base until it has incremented by that amount.
  39 */
  40void __udelay(unsigned long usec)
  41{
  42        ulong ticks = usec2ticks (usec);
  43        wait_ticks (ticks);
  44}
  45
  46/* ------------------------------------------------------------------------- */
  47#ifndef CONFIG_NAND_SPL
  48unsigned long ticks2usec(unsigned long ticks)
  49{
  50        ulong tbclk = get_tbclk();
  51
  52        /* usec = ticks * 1000000 / tbclk
  53         * Multiplication would overflow at ~4.2e3 ticks,
  54         * so we break it up into
  55         * usec = ( ( ticks * 1000) / tbclk ) * 1000;
  56         */
  57        ticks *= 1000L;
  58        ticks /= tbclk;
  59        ticks *= 1000L;
  60
  61        return ((ulong)ticks);
  62}
  63#endif
  64/* ------------------------------------------------------------------------- */
  65
  66int timer_init(void)
  67{
  68        unsigned long temp;
  69
  70        /* reset */
  71        asm volatile("li %0,0 ; mttbl %0 ; mttbu %0;"
  72             : "=&r"(temp) );
  73
  74        return (0);
  75}
  76/* ------------------------------------------------------------------------- */
  77