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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168// SPDX-License-Identifier: GPL-2.0-or-later/* * Copyright 2001 MontaVista Software Inc. * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net * Copyright (c) 2003, 2004 Maciej W. Rozycki * * Common time service routines for MIPS machines. */#include <linux/bug.h>#include <linux/clockchips.h>#include <linux/types.h>#include <linux/kernel.h>#include <linux/init.h>#include <linux/sched.h>#include <linux/param.h>#include <linux/time.h>#include <linux/timex.h>#include <linux/smp.h>#include <linux/spinlock.h>#include <linux/export.h>#include <linux/cpufreq.h>#include <linux/delay.h>
#include <asm/cpu-features.h>#include <asm/cpu-type.h>#include <asm/div64.h>#include <asm/time.h>
#ifdef CONFIG_CPU_FREQ
static DEFINE_PER_CPU(unsigned long, pcp_lpj_ref);static DEFINE_PER_CPU(unsigned long, pcp_lpj_ref_freq);static unsigned long glb_lpj_ref;static unsigned long glb_lpj_ref_freq;
static int cpufreq_callback(struct notifier_block *nb, unsigned long val, void *data){ struct cpufreq_freqs *freq = data; struct cpumask *cpus = freq->policy->cpus; unsigned long lpj; int cpu;
/* * Skip lpj numbers adjustment if the CPU-freq transition is safe for * the loops delay. (Is this possible?) */ if (freq->flags & CPUFREQ_CONST_LOOPS) return NOTIFY_OK;
/* Save the initial values of the lpjes for future scaling. */ if (!glb_lpj_ref) { glb_lpj_ref = boot_cpu_data.udelay_val; glb_lpj_ref_freq = freq->old;
for_each_online_cpu(cpu) { per_cpu(pcp_lpj_ref, cpu) = cpu_data[cpu].udelay_val; per_cpu(pcp_lpj_ref_freq, cpu) = freq->old; } }
/* * Adjust global lpj variable and per-CPU udelay_val number in * accordance with the new CPU frequency. */ if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) || (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) { loops_per_jiffy = cpufreq_scale(glb_lpj_ref, glb_lpj_ref_freq, freq->new);
for_each_cpu(cpu, cpus) { lpj = cpufreq_scale(per_cpu(pcp_lpj_ref, cpu), per_cpu(pcp_lpj_ref_freq, cpu), freq->new); cpu_data[cpu].udelay_val = (unsigned int)lpj; } }
return NOTIFY_OK;}
static struct notifier_block cpufreq_notifier = { .notifier_call = cpufreq_callback,};
static int __init register_cpufreq_notifier(void){ return cpufreq_register_notifier(&cpufreq_notifier, CPUFREQ_TRANSITION_NOTIFIER);}core_initcall(register_cpufreq_notifier);
#endif /* CONFIG_CPU_FREQ */
/* * forward reference */DEFINE_SPINLOCK(rtc_lock);EXPORT_SYMBOL(rtc_lock);
static int null_perf_irq(void){ return 0;}
int (*perf_irq)(void) = null_perf_irq;
EXPORT_SYMBOL(perf_irq);
/* * time_init() - it does the following things. * * 1) plat_time_init() - * a) (optional) set up RTC routines, * b) (optional) calibrate and set the mips_hpt_frequency * (only needed if you intended to use cpu counter as timer interrupt * source) * 2) calculate a couple of cached variables for later usage */
unsigned int mips_hpt_frequency;EXPORT_SYMBOL_GPL(mips_hpt_frequency);
static __init int cpu_has_mfc0_count_bug(void){ switch (current_cpu_type()) { case CPU_R4000PC: case CPU_R4000SC: case CPU_R4000MC: /* * V3.0 is documented as suffering from the mfc0 from count bug. * Afaik this is the last version of the R4000. Later versions * were marketed as R4400. */ return 1;
case CPU_R4400PC: case CPU_R4400SC: case CPU_R4400MC: /* * The published errata for the R4400 up to 3.0 say the CPU * has the mfc0 from count bug. This seems the last version * produced. */ return 1; }
return 0;}
void __init time_init(void){ plat_time_init();
/* * The use of the R4k timer as a clock event takes precedence; * if reading the Count register might interfere with the timer * interrupt, then we don't use the timer as a clock source. * We may still use the timer as a clock source though if the * timer interrupt isn't reliable; the interference doesn't * matter then, because we don't use the interrupt. */ if (mips_clockevent_init() != 0 || !cpu_has_mfc0_count_bug()) init_mips_clocksource();}