55d0b4e3f6
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
457 lines
11 KiB
C
457 lines
11 KiB
C
/*
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* Copyright 2001 MontaVista Software Inc.
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* Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
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* Copyright (c) 2003, 2004 Maciej W. Rozycki
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*
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* Common time service routines for MIPS machines. See
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* Documentation/mips/time.README.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/param.h>
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#include <linux/time.h>
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#include <linux/timex.h>
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#include <linux/smp.h>
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#include <linux/kernel_stat.h>
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <asm/bootinfo.h>
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#include <asm/cache.h>
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#include <asm/compiler.h>
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#include <asm/cpu.h>
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#include <asm/cpu-features.h>
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#include <asm/div64.h>
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#include <asm/sections.h>
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#include <asm/time.h>
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/*
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* The integer part of the number of usecs per jiffy is taken from tick,
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* but the fractional part is not recorded, so we calculate it using the
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* initial value of HZ. This aids systems where tick isn't really an
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* integer (e.g. for HZ = 128).
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*/
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#define USECS_PER_JIFFY TICK_SIZE
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#define USECS_PER_JIFFY_FRAC ((unsigned long)(u32)((1000000ULL << 32) / HZ))
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#define TICK_SIZE (tick_nsec / 1000)
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/*
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* forward reference
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*/
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DEFINE_SPINLOCK(rtc_lock);
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/*
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* By default we provide the null RTC ops
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*/
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static unsigned long null_rtc_get_time(void)
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{
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return mktime(2000, 1, 1, 0, 0, 0);
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}
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static int null_rtc_set_time(unsigned long sec)
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{
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return 0;
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}
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unsigned long (*rtc_mips_get_time)(void) = null_rtc_get_time;
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int (*rtc_mips_set_time)(unsigned long) = null_rtc_set_time;
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int (*rtc_mips_set_mmss)(unsigned long);
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/* how many counter cycles in a jiffy */
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static unsigned long cycles_per_jiffy __read_mostly;
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/* expirelo is the count value for next CPU timer interrupt */
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static unsigned int expirelo;
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/*
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* Null timer ack for systems not needing one (e.g. i8254).
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*/
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static void null_timer_ack(void) { /* nothing */ }
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/*
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* Null high precision timer functions for systems lacking one.
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*/
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static cycle_t null_hpt_read(void)
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{
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return 0;
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}
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/*
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* Timer ack for an R4k-compatible timer of a known frequency.
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*/
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static void c0_timer_ack(void)
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{
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unsigned int count;
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/* Ack this timer interrupt and set the next one. */
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expirelo += cycles_per_jiffy;
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write_c0_compare(expirelo);
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/* Check to see if we have missed any timer interrupts. */
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while (((count = read_c0_count()) - expirelo) < 0x7fffffff) {
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/* missed_timer_count++; */
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expirelo = count + cycles_per_jiffy;
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write_c0_compare(expirelo);
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}
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}
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/*
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* High precision timer functions for a R4k-compatible timer.
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*/
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static cycle_t c0_hpt_read(void)
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{
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return read_c0_count();
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}
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/* For use both as a high precision timer and an interrupt source. */
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static void __init c0_hpt_timer_init(void)
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{
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expirelo = read_c0_count() + cycles_per_jiffy;
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write_c0_compare(expirelo);
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}
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int (*mips_timer_state)(void);
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void (*mips_timer_ack)(void);
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/* last time when xtime and rtc are sync'ed up */
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static long last_rtc_update;
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/*
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* local_timer_interrupt() does profiling and process accounting
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* on a per-CPU basis.
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*
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* In UP mode, it is invoked from the (global) timer_interrupt.
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*
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* In SMP mode, it might invoked by per-CPU timer interrupt, or
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* a broadcasted inter-processor interrupt which itself is triggered
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* by the global timer interrupt.
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*/
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void local_timer_interrupt(int irq, void *dev_id)
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{
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profile_tick(CPU_PROFILING);
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update_process_times(user_mode(get_irq_regs()));
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}
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/*
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* High-level timer interrupt service routines. This function
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* is set as irqaction->handler and is invoked through do_IRQ.
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*/
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irqreturn_t timer_interrupt(int irq, void *dev_id)
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{
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write_seqlock(&xtime_lock);
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mips_timer_ack();
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/*
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* call the generic timer interrupt handling
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*/
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do_timer(1);
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/*
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* If we have an externally synchronized Linux clock, then update
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* CMOS clock accordingly every ~11 minutes. rtc_mips_set_time() has to be
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* called as close as possible to 500 ms before the new second starts.
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*/
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if (ntp_synced() &&
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xtime.tv_sec > last_rtc_update + 660 &&
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(xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
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(xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
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if (rtc_mips_set_mmss(xtime.tv_sec) == 0) {
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last_rtc_update = xtime.tv_sec;
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} else {
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/* do it again in 60 s */
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last_rtc_update = xtime.tv_sec - 600;
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}
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}
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write_sequnlock(&xtime_lock);
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/*
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* In UP mode, we call local_timer_interrupt() to do profiling
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* and process accouting.
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*
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* In SMP mode, local_timer_interrupt() is invoked by appropriate
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* low-level local timer interrupt handler.
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*/
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local_timer_interrupt(irq, dev_id);
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return IRQ_HANDLED;
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}
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int null_perf_irq(void)
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{
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return 0;
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}
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int (*perf_irq)(void) = null_perf_irq;
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EXPORT_SYMBOL(null_perf_irq);
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EXPORT_SYMBOL(perf_irq);
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asmlinkage void ll_timer_interrupt(int irq)
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{
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int r2 = cpu_has_mips_r2;
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irq_enter();
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kstat_this_cpu.irqs[irq]++;
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/*
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* Suckage alert:
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* Before R2 of the architecture there was no way to see if a
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* performance counter interrupt was pending, so we have to run the
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* performance counter interrupt handler anyway.
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*/
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if (!r2 || (read_c0_cause() & (1 << 26)))
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if (perf_irq())
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goto out;
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/* we keep interrupt disabled all the time */
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if (!r2 || (read_c0_cause() & (1 << 30)))
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timer_interrupt(irq, NULL);
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out:
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irq_exit();
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}
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asmlinkage void ll_local_timer_interrupt(int irq)
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{
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irq_enter();
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if (smp_processor_id() != 0)
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kstat_this_cpu.irqs[irq]++;
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/* we keep interrupt disabled all the time */
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local_timer_interrupt(irq, NULL);
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irq_exit();
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}
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/*
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* time_init() - it does the following things.
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*
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* 1) board_time_init() -
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* a) (optional) set up RTC routines,
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* b) (optional) calibrate and set the mips_hpt_frequency
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* (only needed if you intended to use cpu counter as timer interrupt
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* source)
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* 2) setup xtime based on rtc_mips_get_time().
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* 3) calculate a couple of cached variables for later usage
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* 4) plat_timer_setup() -
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* a) (optional) over-write any choices made above by time_init().
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* b) machine specific code should setup the timer irqaction.
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* c) enable the timer interrupt
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*/
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void (*board_time_init)(void);
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unsigned int mips_hpt_frequency;
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static struct irqaction timer_irqaction = {
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.handler = timer_interrupt,
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.flags = IRQF_DISABLED,
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.name = "timer",
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};
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static unsigned int __init calibrate_hpt(void)
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{
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cycle_t frequency, hpt_start, hpt_end, hpt_count, hz;
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const int loops = HZ / 10;
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int log_2_loops = 0;
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int i;
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/*
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* We want to calibrate for 0.1s, but to avoid a 64-bit
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* division we round the number of loops up to the nearest
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* power of 2.
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*/
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while (loops > 1 << log_2_loops)
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log_2_loops++;
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i = 1 << log_2_loops;
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/*
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* Wait for a rising edge of the timer interrupt.
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*/
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while (mips_timer_state());
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while (!mips_timer_state());
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/*
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* Now see how many high precision timer ticks happen
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* during the calculated number of periods between timer
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* interrupts.
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*/
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hpt_start = clocksource_mips.read();
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do {
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while (mips_timer_state());
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while (!mips_timer_state());
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} while (--i);
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hpt_end = clocksource_mips.read();
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hpt_count = (hpt_end - hpt_start) & clocksource_mips.mask;
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hz = HZ;
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frequency = hpt_count * hz;
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return frequency >> log_2_loops;
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}
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struct clocksource clocksource_mips = {
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.name = "MIPS",
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.mask = CLOCKSOURCE_MASK(32),
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static void __init init_mips_clocksource(void)
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{
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u64 temp;
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u32 shift;
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if (!mips_hpt_frequency || clocksource_mips.read == null_hpt_read)
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return;
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/* Calclate a somewhat reasonable rating value */
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clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
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/* Find a shift value */
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for (shift = 32; shift > 0; shift--) {
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temp = (u64) NSEC_PER_SEC << shift;
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do_div(temp, mips_hpt_frequency);
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if ((temp >> 32) == 0)
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break;
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}
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clocksource_mips.shift = shift;
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clocksource_mips.mult = (u32)temp;
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clocksource_register(&clocksource_mips);
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}
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void __init time_init(void)
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{
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if (board_time_init)
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board_time_init();
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if (!rtc_mips_set_mmss)
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rtc_mips_set_mmss = rtc_mips_set_time;
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xtime.tv_sec = rtc_mips_get_time();
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xtime.tv_nsec = 0;
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set_normalized_timespec(&wall_to_monotonic,
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-xtime.tv_sec, -xtime.tv_nsec);
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/* Choose appropriate high precision timer routines. */
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if (!cpu_has_counter && !clocksource_mips.read)
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/* No high precision timer -- sorry. */
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clocksource_mips.read = null_hpt_read;
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else if (!mips_hpt_frequency && !mips_timer_state) {
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/* A high precision timer of unknown frequency. */
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if (!clocksource_mips.read)
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/* No external high precision timer -- use R4k. */
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clocksource_mips.read = c0_hpt_read;
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} else {
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/* We know counter frequency. Or we can get it. */
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if (!clocksource_mips.read) {
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/* No external high precision timer -- use R4k. */
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clocksource_mips.read = c0_hpt_read;
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if (!mips_timer_state) {
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/* No external timer interrupt -- use R4k. */
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mips_timer_ack = c0_timer_ack;
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/* Calculate cache parameters. */
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cycles_per_jiffy =
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(mips_hpt_frequency + HZ / 2) / HZ;
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/*
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* This sets up the high precision
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* timer for the first interrupt.
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*/
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c0_hpt_timer_init();
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}
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}
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if (!mips_hpt_frequency)
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mips_hpt_frequency = calibrate_hpt();
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/* Report the high precision timer rate for a reference. */
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printk("Using %u.%03u MHz high precision timer.\n",
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((mips_hpt_frequency + 500) / 1000) / 1000,
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((mips_hpt_frequency + 500) / 1000) % 1000);
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}
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if (!mips_timer_ack)
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/* No timer interrupt ack (e.g. i8254). */
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mips_timer_ack = null_timer_ack;
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/*
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* Call board specific timer interrupt setup.
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*
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* this pointer must be setup in machine setup routine.
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*
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* Even if a machine chooses to use a low-level timer interrupt,
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* it still needs to setup the timer_irqaction.
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* In that case, it might be better to set timer_irqaction.handler
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* to be NULL function so that we are sure the high-level code
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* is not invoked accidentally.
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*/
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plat_timer_setup(&timer_irqaction);
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init_mips_clocksource();
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}
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#define FEBRUARY 2
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#define STARTOFTIME 1970
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#define SECDAY 86400L
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#define SECYR (SECDAY * 365)
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#define leapyear(y) ((!((y) % 4) && ((y) % 100)) || !((y) % 400))
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#define days_in_year(y) (leapyear(y) ? 366 : 365)
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#define days_in_month(m) (month_days[(m) - 1])
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static int month_days[12] = {
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31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
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};
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void to_tm(unsigned long tim, struct rtc_time *tm)
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{
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long hms, day, gday;
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int i;
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gday = day = tim / SECDAY;
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hms = tim % SECDAY;
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/* Hours, minutes, seconds are easy */
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tm->tm_hour = hms / 3600;
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tm->tm_min = (hms % 3600) / 60;
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tm->tm_sec = (hms % 3600) % 60;
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/* Number of years in days */
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for (i = STARTOFTIME; day >= days_in_year(i); i++)
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day -= days_in_year(i);
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tm->tm_year = i;
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/* Number of months in days left */
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if (leapyear(tm->tm_year))
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days_in_month(FEBRUARY) = 29;
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for (i = 1; day >= days_in_month(i); i++)
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day -= days_in_month(i);
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days_in_month(FEBRUARY) = 28;
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tm->tm_mon = i - 1; /* tm_mon starts from 0 to 11 */
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/* Days are what is left over (+1) from all that. */
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tm->tm_mday = day + 1;
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/*
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* Determine the day of week
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*/
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tm->tm_wday = (gday + 4) % 7; /* 1970/1/1 was Thursday */
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}
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EXPORT_SYMBOL(rtc_lock);
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EXPORT_SYMBOL(to_tm);
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EXPORT_SYMBOL(rtc_mips_set_time);
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EXPORT_SYMBOL(rtc_mips_get_time);
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