/* $NetBSD: apple_pmgr.c,v 1.2 2022/05/10 08:10:28 skrll Exp $ */

/*-
 * Copyright (c) 2022 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Nick Hudson
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: apple_pmgr.c,v 1.2 2022/05/10 08:10:28 skrll Exp $");

#include <sys/param.h>

#include <sys/bus.h>
#include <sys/kmem.h>
#include <sys/queue.h>

#include <libfdt.h>
#include <dev/fdt/fdtvar.h>

/*
 * Power manager registers
 */
#define PMGR_PS_TARGET_MASK     __BITS(3, 0)
#define PMGR_PS_ACTUAL_MASK     __BITS(7, 4)
#define  PMGR_PS_ACTIVE         0xf
#define  PMGR_PS_PWRGATE        0x0

struct apple_pmgr_softc {
        device_t sc_dev;
        bus_space_tag_t sc_bst;
        bus_space_handle_t sc_bsh;
};

#define PMGR_READ(sc, reg) \
        bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))
#define PMGR_WRITE(sc, reg, val) \
        bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))


static const struct device_compatible_entry compat_data[] = {
        { .compat = "apple,pmgr" },
        DEVICE_COMPAT_EOL
};

static void
apple_pmgr_enable(device_t dev, const uint32_t *data, bool enable)
{
        struct apple_pmgr_softc * const sc = device_private(dev);
        const uint32_t pstate = enable ? PMGR_PS_ACTIVE : PMGR_PS_PWRGATE;
        const int phandle = fdtbus_get_phandle_from_native(be32dec(data));

        fdtbus_powerdomain_enable(phandle);

        bus_size_t off;
        bus_size_t size;
        if (fdtbus_get_reg(phandle, 0, &off, &size) != 0 || size != 4) {
                aprint_error(": invalid 'reg' property\n");
                return;
        }

        uint32_t val = PMGR_READ(sc, off);

        val &= ~PMGR_PS_TARGET_MASK;
        val |= __SHIFTIN(pstate, PMGR_PS_TARGET_MASK);
        PMGR_WRITE(sc, off, val);

        for (int timo = 0; timo < 100; timo++) {
                val = PMGR_READ(sc, off);
                if (__SHIFTOUT(val, PMGR_PS_ACTUAL_MASK) == pstate)
                        break;
                delay(1);
        }
}


static int
apple_pmgr_match(device_t parent, cfdata_t cf, void *aux)
{
        struct fdt_attach_args * const faa = aux;

        return of_compatible_match(faa->faa_phandle, compat_data);
}


static void
apple_pmgr_attach(device_t parent, device_t self, void *aux)
{
        struct apple_pmgr_softc * const sc = device_private(self);
        struct fdt_attach_args * const faa = aux;
        const int phandle = faa->faa_phandle;

        bus_addr_t pmgr_addr;
        bus_size_t pmgr_size;

        int error = fdtbus_get_reg(phandle, 0, &pmgr_addr, &pmgr_size);
        if (error) {
                aprint_error(": couldn't get registers\n");
                return;
        }

        sc->sc_dev = self;
        sc->sc_bst = faa->faa_bst;

        error = bus_space_map(faa->faa_bst, pmgr_addr, pmgr_size, 0,
            &sc->sc_bsh);
        if (error) {
                aprint_error(": couldn't map registers: %d\n", error);
                return;
        }

        aprint_naive("\n");
        aprint_normal(": Apple PMGR\n");

        for (int node = OF_child(phandle); node; node = OF_peer(node)) {
                static const struct device_compatible_entry compat_ps[] = {
                        { .compat = "apple,pmgr-pwrstate" },
                        DEVICE_COMPAT_EOL
                };

                if (!of_compatible_match(node, compat_ps))
                        continue;

                static struct fdtbus_powerdomain_controller_func funcs = {
                        .pdc_enable = apple_pmgr_enable,
                };

                fdtbus_register_powerdomain_controller(self, node, &funcs);
        }
}

CFATTACH_DECL_NEW(apple_pmgr, sizeof(struct apple_pmgr_softc),
    apple_pmgr_match, apple_pmgr_attach, NULL, NULL);