/*
 * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
 */

#ifndef _ASM_SPARC_VVAR_DATA_H
#define _ASM_SPARC_VVAR_DATA_H

#include <asm/clocksource.h>
#include <asm/processor.h>
#include <asm/barrier.h>
#include <linux/time.h>
#include <linux/types.h>

struct vvar_data {
        unsigned int seq;

        int vclock_mode;
        struct { /* extract of a clocksource struct */
                u64     cycle_last;
                u64     mask;
                int     mult;
                int     shift;
        } clock;
        /* open coded 'struct timespec' */
        u64             wall_time_sec;
        u64             wall_time_snsec;
        u64             monotonic_time_snsec;
        u64             monotonic_time_sec;
        u64             monotonic_time_coarse_sec;
        u64             monotonic_time_coarse_nsec;
        u64             wall_time_coarse_sec;
        u64             wall_time_coarse_nsec;

        int             tz_minuteswest;
        int             tz_dsttime;
};

extern struct vvar_data *vvar_data;
extern int vdso_fix_stick;

static inline unsigned int vvar_read_begin(const struct vvar_data *s)
{
        unsigned int ret;

repeat:
        ret = READ_ONCE(s->seq);
        if (unlikely(ret & 1)) {
                cpu_relax();
                goto repeat;
        }
        smp_rmb(); /* Finish all reads before we return seq */
        return ret;
}

static inline int vvar_read_retry(const struct vvar_data *s,
                                        unsigned int start)
{
        smp_rmb(); /* Finish all reads before checking the value of seq */
        return unlikely(s->seq != start);
}

static inline void vvar_write_begin(struct vvar_data *s)
{
        ++s->seq;
        smp_wmb(); /* Makes sure that increment of seq is reflected */
}

static inline void vvar_write_end(struct vvar_data *s)
{
        smp_wmb(); /* Makes the value of seq current before we increment */
        ++s->seq;
}


#endif /* _ASM_SPARC_VVAR_DATA_H */