/* $OpenBSD: acpihpet.c,v 1.32 2025/09/16 12:18:10 hshoexer Exp $ */
/*
 * Copyright (c) 2005 Thorsten Lockert <tholo@sigmasoft.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/stdint.h>
#include <sys/timetc.h>

#include <machine/bus.h>
#include <machine/cpu.h>

#include <dev/acpi/acpireg.h>
#include <dev/acpi/acpivar.h>
#include <dev/acpi/acpidev.h>

int acpihpet_attached;

int acpihpet_match(struct device *, void *, void *);
void acpihpet_attach(struct device *, struct device *, void *);
int acpihpet_activate(struct device *, int);
void acpihpet_delay(int);
u_int acpihpet_gettime(struct timecounter *tc);

uint64_t        acpihpet_r(bus_space_tag_t _iot, bus_space_handle_t _ioh,
                    bus_size_t _ioa);
void            acpihpet_w(bus_space_tag_t _iot, bus_space_handle_t _ioh,
                    bus_size_t _ioa, uint64_t _val);

static struct timecounter hpet_timecounter = {
        .tc_get_timecount = acpihpet_gettime,
        .tc_counter_mask = 0xffffffff,
        .tc_frequency = 0,
        .tc_name = 0,
        .tc_quality = 1000,
        .tc_priv = NULL,
        .tc_user = 0,
};

#define HPET_TIMERS     3
struct hpet_regs {
        uint64_t        configuration;
        uint64_t        interrupt_status;
        uint64_t        main_counter;
        struct {        /* timers */
                uint64_t config;
                uint64_t compare;
                uint64_t interrupt;
        } timers[HPET_TIMERS];
};

struct acpihpet_softc {
        struct device           sc_dev;

        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;

        uint32_t                sc_conf;
        struct hpet_regs        sc_save;
};

const struct cfattach acpihpet_ca = {
        sizeof(struct acpihpet_softc), acpihpet_match, acpihpet_attach,
        NULL, acpihpet_activate
};

struct cfdriver acpihpet_cd = {
        NULL, "acpihpet", DV_DULL, CD_COCOVM
};

uint64_t
acpihpet_r(bus_space_tag_t iot, bus_space_handle_t ioh, bus_size_t ioa)
{
        uint64_t val;

        val = bus_space_read_4(iot, ioh, ioa + 4);
        val = val << 32;
        val |= bus_space_read_4(iot, ioh, ioa);
        return (val);
}

void
acpihpet_w(bus_space_tag_t iot, bus_space_handle_t ioh, bus_size_t ioa,
    uint64_t val)
{
        bus_space_write_4(iot, ioh, ioa + 4, val >> 32);
        bus_space_write_4(iot, ioh, ioa, val & 0xffffffff);
}

int
acpihpet_activate(struct device *self, int act)
{
        struct acpihpet_softc *sc = (struct acpihpet_softc *) self;

        switch (act) {
        case DVACT_SUSPEND:
                delay_fini(acpihpet_delay);

                /* stop, then save */
                bus_space_write_4(sc->sc_iot, sc->sc_ioh,
                    HPET_CONFIGURATION, sc->sc_conf);

                sc->sc_save.configuration = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_CONFIGURATION);
                sc->sc_save.interrupt_status = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_INTERRUPT_STATUS);
                sc->sc_save.main_counter = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_MAIN_COUNTER);
                sc->sc_save.timers[0].config = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_TIMER0_CONFIG);
                sc->sc_save.timers[0].interrupt = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_TIMER0_INTERRUPT);
                sc->sc_save.timers[0].compare = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_TIMER0_COMPARE);
                sc->sc_save.timers[1].config = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_TIMER1_CONFIG);
                sc->sc_save.timers[1].interrupt = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_TIMER1_INTERRUPT);
                sc->sc_save.timers[1].compare = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_TIMER1_COMPARE);
                sc->sc_save.timers[2].config = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_TIMER2_CONFIG);
                sc->sc_save.timers[2].interrupt = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_TIMER2_INTERRUPT);
                sc->sc_save.timers[2].compare = acpihpet_r(sc->sc_iot,
                    sc->sc_ioh, HPET_TIMER2_COMPARE);
                break;
        case DVACT_RESUME:
                /* stop, restore, then restart */
                bus_space_write_4(sc->sc_iot, sc->sc_ioh,
                    HPET_CONFIGURATION, sc->sc_conf);

                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_CONFIGURATION, sc->sc_save.configuration);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_INTERRUPT_STATUS, sc->sc_save.interrupt_status);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_MAIN_COUNTER, sc->sc_save.main_counter);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_TIMER0_CONFIG, sc->sc_save.timers[0].config);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_TIMER0_INTERRUPT, sc->sc_save.timers[0].interrupt);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_TIMER0_COMPARE, sc->sc_save.timers[0].compare);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_TIMER1_CONFIG, sc->sc_save.timers[1].config);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_TIMER1_INTERRUPT, sc->sc_save.timers[1].interrupt);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_TIMER1_COMPARE, sc->sc_save.timers[1].compare);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_TIMER2_CONFIG, sc->sc_save.timers[2].config);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_TIMER2_INTERRUPT, sc->sc_save.timers[2].interrupt);
                acpihpet_w(sc->sc_iot, sc->sc_ioh,
                    HPET_TIMER2_COMPARE, sc->sc_save.timers[2].compare);
                bus_space_write_4(sc->sc_iot, sc->sc_ioh,
                    HPET_CONFIGURATION, sc->sc_conf | 1);

                delay_init(acpihpet_delay, 2000);
                break;
        }

        return 0;
}

int
acpihpet_match(struct device *parent, void *match, void *aux)
{
        struct acpi_attach_args *aaa = aux;
        struct acpi_table_header *hdr;

        /*
         * If we do not have a table, it is not us; attach only once
         */
        if (acpihpet_attached || aaa->aaa_table == NULL)
                return (0);

        /*
         * If it is an HPET table, we can attach
         */
        hdr = (struct acpi_table_header *)aaa->aaa_table;
        if (memcmp(hdr->signature, HPET_SIG, sizeof(HPET_SIG) - 1) != 0)
                return (0);

        return (1);
}

void
acpihpet_attach(struct device *parent, struct device *self, void *aux)
{
        struct acpihpet_softc *sc = (struct acpihpet_softc *) self;
        struct acpi_softc *psc = (struct acpi_softc *)parent;
        struct acpi_attach_args *aaa = aux;
        struct acpi_hpet *hpet = (struct acpi_hpet *)aaa->aaa_table;
        uint64_t period, freq;  /* timer period in femtoseconds (10^-15) */
        uint32_t v1, v2;
        int timeout;

        if (acpi_map_address(psc, &hpet->base_address, 0, HPET_REG_SIZE,
            &sc->sc_ioh, &sc->sc_iot))  {
                printf(": can't map i/o space\n");
                return;
        }

        /*
         * Revisions 0x30 through 0x3a of the AMD SB700, with spread
         * spectrum enabled, have an SMM based HPET emulation that's
         * subtly broken.  The hardware is initialized upon first
         * access of the configuration register.  Initialization takes
         * some time during which the configuration register returns
         * 0xffffffff.
         */
        timeout = 1000;
        do {
                if (bus_space_read_4(sc->sc_iot, sc->sc_ioh,
                    HPET_CONFIGURATION) != 0xffffffff)
                        break;
        } while(--timeout > 0);

        if (timeout == 0) {
                printf(": disabled\n");
                return;
        }

        /* enable hpet */
        sc->sc_conf = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
            HPET_CONFIGURATION) & ~1;
        bus_space_write_4(sc->sc_iot, sc->sc_ioh, HPET_CONFIGURATION,
            sc->sc_conf | 1);

        /* make sure hpet is working */
        v1 = bus_space_read_4(sc->sc_iot, sc->sc_ioh, HPET_MAIN_COUNTER);
        delay(1);
        v2 = bus_space_read_4(sc->sc_iot, sc->sc_ioh, HPET_MAIN_COUNTER);
        if (v1 == v2) {
                printf(": counter not incrementing\n");
                bus_space_write_4(sc->sc_iot, sc->sc_ioh,
                    HPET_CONFIGURATION, sc->sc_conf);
                return;
        }

        period = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
            HPET_CAPABILITIES + sizeof(uint32_t));

        /* Period must be > 0 and less than 100ns (10^8 fs) */
        if (period == 0 || period > HPET_MAX_PERIOD) {
                printf(": invalid period\n");
                bus_space_write_4(sc->sc_iot, sc->sc_ioh,
                    HPET_CONFIGURATION, sc->sc_conf);
                return;
        }
        freq = 1000000000000000ull / period;
        printf(": %lld Hz\n", freq);

        hpet_timecounter.tc_frequency = freq;
        hpet_timecounter.tc_priv = sc;
        hpet_timecounter.tc_name = sc->sc_dev.dv_xname;
        tc_init(&hpet_timecounter);

        delay_init(acpihpet_delay, 2000);

#if defined(__amd64__)
        extern void cpu_recalibrate_tsc(struct timecounter *);
        cpu_recalibrate_tsc(&hpet_timecounter);
#endif
        acpihpet_attached++;
}

void
acpihpet_delay(int usecs)
{
        uint64_t count = 0, cycles;
        struct acpihpet_softc *sc = hpet_timecounter.tc_priv;
        uint32_t val1, val2;

        val2 = bus_space_read_4(sc->sc_iot, sc->sc_ioh, HPET_MAIN_COUNTER);
        cycles = usecs * hpet_timecounter.tc_frequency / 1000000;
        while (count < cycles) {
                CPU_BUSY_CYCLE();
                val1 = val2;
                val2 = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
                    HPET_MAIN_COUNTER);
                count += val2 - val1;
        }
}

u_int
acpihpet_gettime(struct timecounter *tc)
{
        struct acpihpet_softc *sc = tc->tc_priv;

        return (bus_space_read_4(sc->sc_iot, sc->sc_ioh, HPET_MAIN_COUNTER));
}