diff options
Diffstat (limited to 'arch/x86/kernel/time_32.c')
| -rw-r--r-- | arch/x86/kernel/time_32.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/arch/x86/kernel/time_32.c b/arch/x86/kernel/time_32.c new file mode 100644 index 0000000..19a6c67 --- /dev/null +++ b/arch/x86/kernel/time_32.c @@ -0,0 +1,236 @@ +/* + * 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 *)®s->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(); +} |