LXR linux/arch/arm/mach-shmobile/timer.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * SH-Mobile Timer
   4 *
   5 * Copyright (C) 2010  Magnus Damm
   6 * Copyright (C) 2002 - 2009  Paul Mundt
   7 */
   8#include <linux/platform_device.h>
   9#include <linux/clocksource.h>
  10#include <linux/delay.h>
  11#include <linux/of_address.h>
  12
  13#include "common.h"
  14
  15void __init shmobile_init_delay(void)
  16{
  17        struct device_node *np;
  18        u32 max_freq = 0;
  19
  20        for_each_of_cpu_node(np) {
  21                u32 freq;
  22
  23                if (!of_property_read_u32(np, "clock-frequency", &freq))
  24                        max_freq = max(max_freq, freq);
  25        }
  26
  27        if (!max_freq)
  28                return;
  29
  30        /*
  31         * Calculate a worst-case loops-per-jiffy value
  32         * based on maximum cpu core hz setting and the
  33         * __delay() implementation in arch/arm/lib/delay.S.
  34         *
  35         * This will result in a longer delay than expected
  36         * when the cpu core runs on lower frequencies.
  37         */
  38
  39        if (!preset_lpj)
  40                preset_lpj = max_freq / HZ;
  41}
  42