/* 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 <asm/lowcore.h>
#include <linux/time64.h>

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

extern u64 clock_comparator_max;

/* 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);

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 long physical_clock;
        unsigned long long tod_offset;
        unsigned long long logical_tod_offset;
        unsigned long 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]; };                               \
        register unsigned int reg0 asm("0") = func;                     \
        register unsigned long reg1 asm("1") = (unsigned long) (ptff_block);\
        int rc;                                                         \
                                                                        \
        asm volatile(                                                   \
                "       .word   0x0104\n"                               \
                "       ipm     %0\n"                                   \
                "       srl     %0,28\n"                                \
                : "=d" (rc), "+m" (*(struct addrtype *) reg1)           \
                : "d" (reg0), "d" (reg1) : "cc");                       \
        rc;                                                             \
})

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

#define CLOCK_TICK_RATE         1193180 /* Underlying HZ */
#define STORE_CLOCK_EXT_SIZE    16      /* stcke writes 16 bytes */

typedef unsigned long long cycles_t;

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

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

static inline unsigned long long get_tod_clock(void)
{
        unsigned char clk[STORE_CLOCK_EXT_SIZE];

        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_phys_clock(unsigned long *clock);
void init_cpu_timer(void);
unsigned long long monotonic_clock(void);

extern unsigned char tod_clock_base[16] __aligned(8);

/**
 * get_clock_monotonic - returns current time in clock rate units
 *
 * The caller must ensure that preemption is disabled.
 * The clock and tod_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() - *(unsigned long long *) &tod_clock_base[1];
}

/**
 * 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 long tod_to_ns(unsigned long 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 long a, unsigned long long b)
{
        if (MACHINE_HAS_SCC)
                return (long long) a > (long 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 long a, unsigned long long b)
{
        if (MACHINE_HAS_SCC)
                return (long long) a >= (long long) b;
        return a >= b;
}

#endif