/* * Alpha-specific clock support * * Copyright (C) 2000 FSM Labs (http://www.fsmlabs.com/) *  Written by Cort Dougan <cort@fsmlabs.com> */#include <linux/module.h>#include <linux/kernel.h>#include <linux/errno.h>#include <linux/sched.h>#include <linux/timex.h>#include <linux/mc146818rtc.h>#include <asm/smp.h>#include <asm/system.h>#include <asm/io.h>#include <asm/hwrpb.h>#include <rtl_core.h>#include <rtl_time.h>#include <rtl_sync.h>#include <rtl.h>MODULE_AUTHOR("Cort Dougan <cort@fsmlabs.com>");MODULE_DESCRIPTION("RTLinux Alpha Timer Module");static unsigned long hrtime_last_tick = 0;static __u32 cycles_last_tick = 0;struct rtl_clock _i8254_clock;static unsigned int clock_counter; /* current latch value */#define wait_value(x) do {; } while ((inb(0x61) & 0x20) != (x))#define wait_cycle() do { wait_value(0); wait_value(0x20); } while (0)#define WRITE_COUNTER_ZERO16(x)  { \	outb_p(x&0xff,0x40); outb_p((x>>8)&0xff,0x40);\      	clock_counter =x; \} #define WRITE_COUNTER_ZERO8(x)  { \	outb_p(x&0xff,0x40); \	clock_counter =x; \}#define WRITE_COUNTER_ZERO_ONESHOT(x) WRITE_COUNTER_ZERO16(x)#define CLATCH (1024 * 32)#define NLOOPS 50#define READ_CNT0(var) \{ var = inb(0x40); var |= (inb(0x40) << 8); }#define READ_CNT2(var) \{ var = inb(0x42); var |= (inb(0x42) << 8); }#define LATCH2 0x8000#define LATCH_CNT0() \outb(0xd2, 0x43);#define LATCH_CNT0_AND_2() \outb(0xda, 0x43);#define LATCH_CNT2() \outb(0xd8, 0x43);static inline long RTIME_to_8254_ticks(long t){	return t / (NSECS_PER_SEC / CLOCK_TICK_RATE);}static int _8254_setperiodic (clockid_t c, hrtime_t interval){	long t;	t = RTIME_to_8254_ticks (interval) + 1;	if(t < 2)		t = 2;	else if ( t > 0xffff )		t = 0xffff;	outb_p(0x34,0x43);              /* binary, mode 2, LSB/MSB, ch 0 */	WRITE_COUNTER_ZERO16 (t);		_i8254_clock.value = gethrtime();	_i8254_clock.resolution = interval;	_i8254_clock.arch.istimerset = 1;	return 0;}	static int _8254_setoneshot (clockid_t c, hrtime_t interval){	long t;	t = RTIME_to_8254_ticks (interval);	if (t < 1) 		t = 1;	else if (t > 0xffff)		t = 0xffff;		WRITE_COUNTER_ZERO_ONESHOT(t);	_i8254_clock.arch.istimerset = 1;	return 0;}int _8254_settimermode (struct rtl_clock *c, int mode){	if (mode == RTL_CLOCK_MODE_PERIODIC) {		outb_p(0x30, 0x43);/* 8254, channel 0, mode 0, lsb+msb */		outb_p(0x34, 0x43); /* binary, mode 2, LSB/MSB, ch 0 */		_i8254_clock.mode = mode;		_i8254_clock.settimer = _8254_setperiodic;		_i8254_clock.arch.count_irqs = 0;	} else if (mode == RTL_CLOCK_MODE_ONESHOT) {		outb_p(0x30, 0x43);    /* 8254, channel 0, mode 0, lsb+msb */		_i8254_clock.mode = mode;		_i8254_clock.settimer = _8254_setoneshot;		_i8254_clock.resolution = HRTICKS_PER_SEC / CLOCK_TICK_RATE;	} else {		return -EINVAL;	}	return 0;}static unsigned int _8254_irq(unsigned int irq, struct pt_regs *regs){	/* keep track of the cycle timer */	__u32 x;	rdtscl(x);	hrtime_last_tick += ((hrtime_t)(x - cycles_last_tick) * (hrtime_t)NSECS_PER_SEC) / (ulong)hwrpb->cycle_freq;	cycles_last_tick = x;	if (_i8254_clock.mode == RTL_CLOCK_MODE_PERIODIC) {		if (test_and_set_bit(0, &_i8254_clock.arch.count_irqs)) {			_i8254_clock.value += _i8254_clock.resolution;		}	} else {		_i8254_clock.arch.istimerset = 0;	}	rtl_hard_enable_irq(0);	_i8254_clock.handler(regs);	return 0;}static int _8254_init (clockid_t clock){	int flags;	rtl_no_interrupts (flags);	rdtscl(cycles_last_tick);		if ( rtl_request_global_irq(0, _8254_irq) )	{		printk("_8254_init(): failed to get irq for timer\n");		return -1;	}	_8254_settimermode (clock, RTL_CLOCK_MODE_ONESHOT);	rtl_restore_interrupts (flags);	return 0;}static void _8254_uninit (clockid_t clock){	if (clock -> mode == RTL_CLOCK_MODE_UNINITIALIZED) {		return;	}	clock->handler = RTL_CLOCK_DEFAULTS.handler;	rtl_free_global_irq(0);	clock -> mode = RTL_CLOCK_MODE_UNINITIALIZED;}hrtime_t _gethrtime(struct rtl_clock *c){	return gethrtime();}hrtime_t gethrtime(void){	u32 x = 0;	rdtscl(x);	x -= cycles_last_tick;	return (((ulong)x * (ulong)NSECS_PER_SEC) / (ulong)hwrpb->cycle_freq)		+ hrtime_last_tick;}hrtime_t gethrtimeres(void){	return NSECS_PER_SEC / hwrpb->cycle_freq;}int rtl_create_clock_8254(void){	_i8254_clock = RTL_CLOCK_DEFAULTS;	_i8254_clock.gethrtime = _gethrtime;	_i8254_clock.init = _8254_init;	_i8254_clock.uninit = _8254_uninit;	_i8254_clock.settimermode = _8254_settimermode;	return 0;}clockid_t rtl_getbestclock (unsigned int cpu){	return &_i8254_clock;}int init_module (void){	rtl_create_clock_8254();	rtl_init_standard_clocks();	return 0;}void cleanup_module(void){	rtl_cleanup_standard_clocks();	_8254_uninit(&_i8254_clock);}