/* SPDX-License-Identifier: GPL-2.0 */
/*
 *  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 <linux/preempt.h>
#include <linux/time64.h>
#include <asm/lowcore.h>

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

extern u64 clock_comparator_max;

union tod_clock {
        __uint128_t val;
        struct {
                __uint128_t ei  :  8; /* epoch index */
                __uint128_t tod : 64; /* bits 0-63 of tod clock */
                __uint128_t     : 40;
                __uint128_t pf  : 16; /* programmable field */
        };
        struct {
                __uint128_t eitod : 72; /* epoch index + bits 0-63 tod clock */
                __uint128_t       : 56;
        };
        struct {
                __uint128_t us  : 60; /* micro-seconds */
                __uint128_t sus : 12; /* sub-microseconds */
                __uint128_t     : 56;
        };
} __packed;

/* 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_ext_cc(union tod_clock *clk)
{
        int cc;

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

static inline void store_tod_clock_ext(union tod_clock *tod)
{
        asm volatile("stcke %0" : "=Q" (*tod) : : "cc");
}

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

static inline void set_tod_programmable_field(u16 val)
{
        asm volatile(
                "       lgr     0,%[val]\n"
                "       sckpf\n"
                :
                : [val] "d" ((unsigned long)val)
                : "0");
}

void clock_comparator_work(void);

void __init time_early_init(void);

extern unsigned char ptff_function_mask[16];

/* Function codes for the ptff instruction. */
#define PTFF_QAF        0x00    /* query available functions */
#define PTFF_QTO        0x01    /* query tod offset */
#define PTFF_QSI        0x02    /* query steering information */
#define PTFF_QUI        0x04    /* query UTC information */
#define PTFF_ATO        0x40    /* adjust tod offset */
#define PTFF_STO        0x41    /* set tod offset */
#define PTFF_SFS        0x42    /* set fine steering rate */
#define PTFF_SGS        0x43    /* set gross steering rate */

/* Query TOD offset result */
struct ptff_qto {
        unsigned long physical_clock;
        unsigned long tod_offset;
        unsigned long logical_tod_offset;
        unsigned long tod_epoch_difference;
} __packed;

static inline int ptff_query(unsigned int nr)
{
        unsigned char *ptr;

        ptr = ptff_function_mask + (nr >> 3);
        return (*ptr & (0x80 >> (nr & 7))) != 0;
}

/* Query UTC information result */
struct ptff_qui {
        unsigned int tm : 2;
        unsigned int ts : 2;
        unsigned int : 28;
        unsigned int pad_0x04;
        unsigned long leap_event;
        short old_leap;
        short new_leap;
        unsigned int pad_0x14;
        unsigned long prt[5];
        unsigned long cst[3];
        unsigned int skew;
        unsigned int pad_0x5c[41];
} __packed;

/*
 * ptff - Perform timing facility function
 * @ptff_block: Pointer to ptff parameter block
 * @len: Length of parameter block
 * @func: Function code
 * Returns: Condition code (0 on success)
 */
#define ptff(ptff_block, len, func)                                     \
({                                                                      \
        struct addrtype { char _[len]; };                               \
        unsigned int reg0 = func;                                       \
        unsigned long reg1 = (unsigned long)(ptff_block);               \
        int rc;                                                         \
                                                                        \
        asm volatile(                                                   \
                "       lgr     0,%[reg0]\n"                            \
                "       lgr     1,%[reg1]\n"                            \
                "       .insn   e,0x0104\n"                             \
                "       ipm     %[rc]\n"                                \
                "       srl     %[rc],28\n"                             \
                : [rc] "=&d" (rc), "+m" (*(struct addrtype *)reg1)      \
                : [reg0] "d" (reg0), [reg1] "d" (reg1)                  \
                : "cc", "0", "1");                                      \
        rc;                                                             \
})

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

        old = S390_lowcore.clock_comparator;
        S390_lowcore.clock_comparator = clock_comparator_max;
        set_clock_comparator(S390_lowcore.clock_comparator);
        return old;
}

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

#define CLOCK_TICK_RATE         1193180 /* Underlying HZ */

typedef unsigned long cycles_t;

static inline unsigned long get_tod_clock(void)
{
        union tod_clock clk;

        store_tod_clock_ext(&clk);
        return clk.tod;
}

static inline unsigned long get_tod_clock_fast(void)
{
#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
        unsigned 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_phys_clock(unsigned long *clock);
void init_cpu_timer(void);

extern union tod_clock tod_clock_base;

/**
 * get_clock_monotonic - returns current time in clock rate units
 *
 * The clock and tod_clock_base get changed via stop_machine.
 * Therefore preemption must be disabled, otherwise the returned
 * value is not guaranteed to be monotonic.
 */
static inline unsigned long get_tod_clock_monotonic(void)
{
        unsigned long tod;

        preempt_disable_notrace();
        tod = get_tod_clock() - tod_clock_base.tod;
        preempt_enable_notrace();
        return tod;
}

/**
 * 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 == 2^9 * th + tl (th upper 55 bits, tl lower 9 bits)
 * we end up with
 *
 *    ns = ((2^9 * th + tl) * 125 ) >> 9;
 * -> ns = (th * 125) + ((tl * 125) >> 9);
 *
 */
static inline unsigned long tod_to_ns(unsigned long todval)
{
        return ((todval >> 9) * 125) + (((todval & 0x1ff) * 125) >> 9);
}

/**
 * tod_after - compare two 64 bit TOD values
 * @a: first 64 bit TOD timestamp
 * @b: second 64 bit TOD timestamp
 *
 * Returns: true if a is later than b
 */
static inline int tod_after(unsigned long a, unsigned long b)
{
        if (MACHINE_HAS_SCC)
                return (long) a > (long) b;
        return a > b;
}

/**
 * tod_after_eq - compare two 64 bit TOD values
 * @a: first 64 bit TOD timestamp
 * @b: second 64 bit TOD timestamp
 *
 * Returns: true if a is later than b
 */
static inline int tod_after_eq(unsigned long a, unsigned long b)
{
        if (MACHINE_HAS_SCC)
                return (long) a >= (long) b;
        return a >= b;
}

#endif