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+/*
+ * linux/arch/i386/kernel/time.c
+ *
+ * Copyright (C) 1991, 1992, 1995 Linus Torvalds
+ *
+ * This file contains the PC-specific time handling details:
+ * reading the RTC at bootup, etc..
+ * 1994-07-02 Alan Modra
+ * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
+ * 1995-03-26 Markus Kuhn
+ * fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
+ * precision CMOS clock update
+ * 1996-05-03 Ingo Molnar
+ * fixed time warps in do_[slow|fast]_gettimeoffset()
+ * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
+ * "A Kernel Model for Precision Timekeeping" by Dave Mills
+ * 1998-09-05 (Various)
+ * More robust do_fast_gettimeoffset() algorithm implemented
+ * (works with APM, Cyrix 6x86MX and Centaur C6),
+ * monotonic gettimeofday() with fast_get_timeoffset(),
+ * drift-proof precision TSC calibration on boot
+ * (C. Scott Ananian <cananian@alumni.princeton.edu>, Andrew D.
+ * Balsa <andrebalsa@altern.org>, Philip Gladstone <philip@raptor.com>;
+ * ported from 2.0.35 Jumbo-9 by Michael Krause <m.krause@tu-harburg.de>).
+ * 1998-12-16 Andrea Arcangeli
+ * Fixed Jumbo-9 code in 2.1.131: do_gettimeofday was missing 1 jiffy
+ * because was not accounting lost_ticks.
+ * 1998-12-24 Copyright (C) 1998 Andrea Arcangeli
+ * Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
+ * serialize accesses to xtime/lost_ticks).
+ */
+
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/module.h>
+#include <linux/sysdev.h>
+#include <linux/bcd.h>
+#include <linux/efi.h>
+#include <linux/mca.h>
+
+#include <asm/io.h>
+#include <asm/smp.h>
+#include <asm/irq.h>
+#include <asm/msr.h>
+#include <asm/delay.h>
+#include <asm/mpspec.h>
+#include <asm/uaccess.h>
+#include <asm/processor.h>
+#include <asm/timer.h>
+#include <asm/time.h>
+
+#include "mach_time.h"
+
+#include <linux/timex.h>
+
+#include <asm/hpet.h>
+
+#include <asm/arch_hooks.h>
+
+#include "io_ports.h"
+
+#include <asm/i8259.h>
+
+#include "do_timer.h"
+
+unsigned int cpu_khz; /* Detected as we calibrate the TSC */
+EXPORT_SYMBOL(cpu_khz);
+
+DEFINE_SPINLOCK(rtc_lock);
+EXPORT_SYMBOL(rtc_lock);
+
+/*
+ * This is a special lock that is owned by the CPU and holds the index
+ * register we are working with. It is required for NMI access to the
+ * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details.
+ */
+volatile unsigned long cmos_lock = 0;
+EXPORT_SYMBOL(cmos_lock);
+
+/* Routines for accessing the CMOS RAM/RTC. */
+unsigned char rtc_cmos_read(unsigned char addr)
+{
+ unsigned char val;
+ lock_cmos_prefix(addr);
+ outb_p(addr, RTC_PORT(0));
+ val = inb_p(RTC_PORT(1));
+ lock_cmos_suffix(addr);
+ return val;
+}
+EXPORT_SYMBOL(rtc_cmos_read);
+
+void rtc_cmos_write(unsigned char val, unsigned char addr)
+{
+ lock_cmos_prefix(addr);
+ outb_p(addr, RTC_PORT(0));
+ outb_p(val, RTC_PORT(1));
+ lock_cmos_suffix(addr);
+}
+EXPORT_SYMBOL(rtc_cmos_write);
+
+static int set_rtc_mmss(unsigned long nowtime)
+{
+ int retval;
+ unsigned long flags;
+
+ /* gets recalled with irq locally disabled */
+ /* XXX - does irqsave resolve this? -johnstul */
+ spin_lock_irqsave(&rtc_lock, flags);
+ retval = set_wallclock(nowtime);
+ spin_unlock_irqrestore(&rtc_lock, flags);
+
+ return retval;
+}
+
+
+int timer_ack;
+
+unsigned long profile_pc(struct pt_regs *regs)
+{
+ unsigned long pc = instruction_pointer(regs);
+
+#ifdef CONFIG_SMP
+ if (!v8086_mode(regs) && SEGMENT_IS_KERNEL_CODE(regs->xcs) &&
+ in_lock_functions(pc)) {
+#ifdef CONFIG_FRAME_POINTER
+ return *(unsigned long *)(regs->ebp + 4);
+#else
+ unsigned long *sp = (unsigned long *)&regs->esp;
+
+ /* Return address is either directly at stack pointer
+ or above a saved eflags. Eflags has bits 22-31 zero,
+ kernel addresses don't. */
+ if (sp[0] >> 22)
+ return sp[0];
+ if (sp[1] >> 22)
+ return sp[1];
+#endif
+ }
+#endif
+ return pc;
+}
+EXPORT_SYMBOL(profile_pc);
+
+/*
+ * This is the same as the above, except we _also_ save the current
+ * Time Stamp Counter value at the time of the timer interrupt, so that
+ * we later on can estimate the time of day more exactly.
+ */
+irqreturn_t timer_interrupt(int irq, void *dev_id)
+{
+#ifdef CONFIG_X86_IO_APIC
+ if (timer_ack) {
+ /*
+ * Subtle, when I/O APICs are used we have to ack timer IRQ
+ * manually to reset the IRR bit for do_slow_gettimeoffset().
+ * This will also deassert NMI lines for the watchdog if run
+ * on an 82489DX-based system.
+ */
+ spin_lock(&i8259A_lock);
+ outb(0x0c, PIC_MASTER_OCW3);
+ /* Ack the IRQ; AEOI will end it automatically. */
+ inb(PIC_MASTER_POLL);
+ spin_unlock(&i8259A_lock);
+ }
+#endif
+
+ do_timer_interrupt_hook();
+
+ if (MCA_bus) {
+ /* The PS/2 uses level-triggered interrupts. You can't
+ turn them off, nor would you want to (any attempt to
+ enable edge-triggered interrupts usually gets intercepted by a
+ special hardware circuit). Hence we have to acknowledge
+ the timer interrupt. Through some incredibly stupid
+ design idea, the reset for IRQ 0 is done by setting the
+ high bit of the PPI port B (0x61). Note that some PS/2s,
+ notably the 55SX, work fine if this is removed. */
+
+ u8 irq_v = inb_p( 0x61 ); /* read the current state */
+ outb_p( irq_v|0x80, 0x61 ); /* reset the IRQ */
+ }
+
+ return IRQ_HANDLED;
+}
+
+/* not static: needed by APM */
+unsigned long read_persistent_clock(void)
+{
+ unsigned long retval;
+ unsigned long flags;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+
+ retval = get_wallclock();
+
+ spin_unlock_irqrestore(&rtc_lock, flags);
+
+ return retval;
+}
+
+int update_persistent_clock(struct timespec now)
+{
+ return set_rtc_mmss(now.tv_sec);
+}
+
+extern void (*late_time_init)(void);
+/* Duplicate of time_init() below, with hpet_enable part added */
+void __init hpet_time_init(void)
+{
+ if (!hpet_enable())
+ setup_pit_timer();
+ time_init_hook();
+}
+
+/*
+ * This is called directly from init code; we must delay timer setup in the
+ * HPET case as we can't make the decision to turn on HPET this early in the
+ * boot process.
+ *
+ * The chosen time_init function will usually be hpet_time_init, above, but
+ * in the case of virtual hardware, an alternative function may be substituted.
+ */
+void __init time_init(void)
+{
+ tsc_init();
+ late_time_init = choose_time_init();
+}