/*      $OpenBSD: sysreg.c,v 1.6 2021/10/24 17:52:28 mpi Exp $  */

/*
 * Copyright (c) 2015 Jonathan Gray <jsg@openbsd.org>
 *
 * 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 <machine/bus.h>
#include <machine/fdt.h>

#include <armv7/armv7/armv7_machdep.h>

#include <dev/ofw/openfirm.h>
#include <dev/ofw/fdt.h>

#define SYS_ID                  0x00
#define SYS_PROCID0             0x84
#define SYS_PROCID1             0x88
#define SYS_CFGDATA             0xa0
#define SYS_CFGCTRL             0xa4
#define SYS_CFGSTAT             0xa8

#define SYS_CFG_WRITE           (1 << 30)
#define SYS_CFG_START           (1U << 31)

#define SYS_CFG_RESET           5
#define SYS_CFG_SHUTDOWN        8
#define SYS_CFG_REBOOT          9

#define SYS_CFGSTAT_COMPLETE    (1 << 0)
#define SYS_CFGSTAT_ERROR       (1 << 1)

struct sysreg_softc {
        struct device           sc_dev;
        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;
};

struct sysreg_softc *sysreg_sc;

int sysreg_match(struct device *, void *, void *);
void sysreg_attach(struct device *, struct device *, void *);
void sysconf_function(struct sysreg_softc *, int);
void sysconf_reboot(void);
void sysconf_shutdown(void);

const struct cfattach sysreg_ca = {
        sizeof (struct sysreg_softc), sysreg_match, sysreg_attach
};

struct cfdriver sysreg_cd = {
        NULL, "sysreg", DV_DULL
};

int
sysreg_match(struct device *parent, void *match, void *aux)
{
        struct fdt_attach_args *faa = aux;

        return OF_is_compatible(faa->fa_node, "arm,vexpress-sysreg");
}

void
sysreg_attach(struct device *parent, struct device *self, void *aux)
{
        struct fdt_attach_args *faa = aux;
        struct sysreg_softc *sc = (struct sysreg_softc *)self;
        uint32_t id;

        sc->sc_iot = faa->fa_iot;
        if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
            faa->fa_reg[0].size, 0, &sc->sc_ioh))
                panic(": bus_space_map failed!");
        sysreg_sc = sc;
        
        id = bus_space_read_4(sc->sc_iot, sc->sc_ioh, SYS_ID);
        printf(": ID 0x%x", id);

        id = bus_space_read_4(sc->sc_iot, sc->sc_ioh, SYS_PROCID0);
        printf(" PROCID0 0x%x\n", id);

        cpuresetfn = sysconf_reboot;
        powerdownfn = sysconf_shutdown;
}

void
sysconf_function(struct sysreg_softc *sc, int function)
{
        int dcc, site, position, device;

        dcc = 0;
        site = 0;
        position = 0;
        device = 0;

        bus_space_write_4(sc->sc_iot, sc->sc_ioh, SYS_CFGSTAT, 0);
        bus_space_write_4(sc->sc_iot, sc->sc_ioh, SYS_CFGCTRL,
            SYS_CFG_START | SYS_CFG_WRITE |
            (dcc << 26) | (function << 20) | (site << 16) |
            (position << 12) | device);

        while ((bus_space_read_4(sc->sc_iot, sc->sc_ioh, SYS_CFGSTAT) &
            SYS_CFGSTAT_COMPLETE) == 0);

        if (bus_space_read_4(sc->sc_iot, sc->sc_ioh, SYS_CFGSTAT) &
            SYS_CFGSTAT_ERROR)
                printf("SYS_CFGSTAT error\n");
}

void
sysconf_reboot(void)
{
        struct sysreg_softc *sc = sysreg_sc;

        if (sc == NULL)
                return;

        sysconf_function(sc, SYS_CFG_REBOOT);
}

void
sysconf_shutdown(void)
{
        struct sysreg_softc *sc = sysreg_sc;

        if (sc == NULL)
                return;

        sysconf_function(sc, SYS_CFG_SHUTDOWN);
}