/* Ported over from i386 by AK, original copyright was: * * (C) Dominik Brodowski <linux@brodo.de> 2003 * * Driver to use the Power Management Timer (PMTMR) available in some * southbridges as primary timing source for the Linux kernel. * * Based on parts of linux/drivers/acpi/hardware/hwtimer.c, timer_pit.c, * timer_hpet.c, and on Arjan van de Ven's implementation for 2.4. * * This file is licensed under the GPL v2. * * Dropped all the hardware bug workarounds for now. Hopefully they * are not needed on 64bit chipsets. */ #include <linux/jiffies.h>#include <linux/kernel.h>#include <linux/time.h>#include <linux/init.h>#include <linux/cpumask.h>#include <asm/io.h>#include <asm/proto.h>#include <asm/msr.h>#include <asm/vsyscall.h> /* The I/O port the PMTMR resides at. * The location is detected during setup_arch(), * in arch/i386/kernel/acpi/boot.c */u32 pmtmr_ioport; /* value of the Power timer at last timer interrupt */static u32 offset_delay;static u32 last_pmtmr_tick; #define ACPI_PM_MASK 0xFFFFFF /* limit it to 24 bits */ static inline u32 cyc2us(u32 cycles){	/* The Power Management Timer ticks at 3.579545 ticks per microsecond.	 * 1 / PM_TIMER_FREQUENCY == 0.27936511 =~ 286/1024 [error: 0.024%]	 *	 * Even with HZ = 100, delta is at maximum 35796 ticks, so it can	 * easily be multiplied with 286 (=0x11E) without having to fear	 * u32 overflows.	 */	cycles *= 286;	return (cycles >> 10);} int pmtimer_mark_offset(void){	static int first_run = 1;	unsigned long tsc;	u32 lost; 	u32 tick = inl(pmtmr_ioport);	u32 delta; 	delta = cyc2us((tick - last_pmtmr_tick) & ACPI_PM_MASK); 	last_pmtmr_tick = tick;	monotonic_base += delta * NSEC_PER_USEC; 	delta += offset_delay; 	lost = delta / (USEC_PER_SEC / HZ);	offset_delay = delta % (USEC_PER_SEC / HZ); 	rdtscll(tsc);	vxtime.last_tsc = tsc - offset_delay * (u64)cpu_khz / 1000; 	/* don't calculate delay for first run,	   or if we've got less then a tick */	if (first_run || (lost < 1)) {		first_run = 0;		offset_delay = 0;	} 	return lost - 1;} static unsigned pmtimer_wait_tick(void){	u32 a, b;	for (a = b = inl(pmtmr_ioport) & ACPI_PM_MASK;	     a == b;	     b = inl(pmtmr_ioport) & ACPI_PM_MASK)		cpu_relax();	return b;} /* note: wait time is rounded up to one tick */void pmtimer_wait(unsigned us){	u32 a, b;	a = pmtimer_wait_tick();	do {		b = inl(pmtmr_ioport);		cpu_relax();	} while (cyc2us(b - a) < us);} void pmtimer_resume(void){	last_pmtmr_tick = inl(pmtmr_ioport);} unsigned int do_gettimeoffset_pm(void){	u32 now, offset, delta = 0; 	offset = last_pmtmr_tick;	now = inl(pmtmr_ioport);	delta = (now - offset) & ACPI_PM_MASK; 	return offset_delay + cyc2us(delta);}  static int __init nopmtimer_setup(char *s){	pmtmr_ioport = 0;	return 1;} __setup("nopmtimer", nopmtimer_setup);