/*
* S390 version
* Copyright IBM Corp. 1999
*
* Derived from "include/asm-i386/timex.h"
* Copyright (C) 1992, Linus Torvalds
*/

#ifndef _ASM_S390_TIMEX_H
#define _ASM_S390_TIMEX_H

#include <asm/lowcore.h>

/* The value of the TOD clock for 1.1.1970. */
#define TOD_UNIX_EPOCH 0x7d91048bca000000ULL

/* Inline functions for clock register access. */
static inline int set_tod_clock(__u64 time)
{
int cc;

asm volatile(
" sck %1\n"
" ipm %0\n"
" srl %0,28\n"
: "=d" (cc) : "Q" (time) : "cc");
return cc;
}

static inline int store_tod_clock(__u64 *time)
{
int cc;

asm volatile(
" stck %1\n"
" ipm %0\n"
" srl %0,28\n"
: "=d" (cc), "=Q" (*time) : : "cc");
return cc;
}

static inline void set_clock_comparator(__u64 time)
{
asm volatile("sckc %0" : : "Q" (time));
}

static inline void store_clock_comparator(__u64 *time)
{
asm volatile("stckc %0" : "=Q" (*time));
}

void clock_comparator_work(void);

static inline unsigned long long local_tick_disable(void)
{
unsigned long long old;

old = S390_lowcore.clock_comparator;
S390_lowcore.clock_comparator = -1ULL;
set_clock_comparator(S390_lowcore.clock_comparator);
return old;
}

static inline void local_tick_enable(unsigned long long comp)
{
S390_lowcore.clock_comparator = comp;
set_clock_comparator(S390_lowcore.clock_comparator);
}

#define CLOCK_TICK_RATE 1193180 /* Underlying HZ */

typedef unsigned long long cycles_t;

static inline void get_tod_clock_ext(char clk[16])
{
typedef struct { char _[sizeof(clk)]; } addrtype;

asm volatile("stcke %0" : "=Q" (*(addrtype *) clk) : : "cc");
}

static inline unsigned long long get_tod_clock(void)
{
unsigned char clk[16];
get_tod_clock_ext(clk);
return *((unsigned long long *)&clk[1]);
}

static inline unsigned long long get_tod_clock_fast(void)
{
#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
unsigned long long clk;

asm volatile("stckf %0" : "=Q" (clk) : : "cc");
return clk;
#else
return get_tod_clock();
#endif
}

static inline cycles_t get_cycles(void)
{
return (cycles_t) get_tod_clock() >> 2;
}

int get_sync_clock(unsigned long long *clock);
void init_cpu_timer(void);
unsigned long long monotonic_clock(void);

void tod_to_timeval(__u64, struct timespec *);

static inline
void stck_to_timespec(unsigned long long stck, struct timespec *ts)
{
tod_to_timeval(stck - TOD_UNIX_EPOCH, ts);
}

extern u64 sched_clock_base_cc;

/**
* get_clock_monotonic - returns current time in clock rate units
*
* The caller must ensure that preemption is disabled.
* The clock and sched_clock_base get changed via stop_machine.
* Therefore preemption must be disabled when calling this
* function, otherwise the returned value is not guaranteed to
* be monotonic.
*/
static inline unsigned long long get_tod_clock_monotonic(void)
{
return get_tod_clock() - sched_clock_base_cc;
}

/**
* tod_to_ns - convert a TOD format value to nanoseconds
* @todval: to be converted TOD format value
* Returns: number of nanoseconds that correspond to the TOD format value
*
* Converting a 64 Bit TOD format value to nanoseconds means that the value
* must be divided by 4.096. In order to achieve that we multiply with 125
* and divide by 512:
*
* ns = (todval * 125) >> 9;
*
* In order to avoid an overflow with the multiplication we can rewrite this.
* With a split todval == 2^32 * th + tl (th upper 32 bits, tl lower 32 bits)
* we end up with
*
* ns = ((2^32 * th + tl) * 125 ) >> 9;
* -> ns = (2^23 * th * 125) + ((tl * 125) >> 9);
*
*/
static inline unsigned long long tod_to_ns(unsigned long long todval)
{
unsigned long long ns;

ns = ((todval >> 32) << 23) * 125;
ns += ((todval & 0xffffffff) * 125) >> 9;
return ns;
}

#endif