/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2011 Nathan Whitehorn
 * All rights reserved.
 *
 * 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 AUTHOR 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 AUTHOR 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/param.h>
#include <sys/systm.h>
#include <sys/module.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/rman.h>

#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_pci.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/ofwpci.h>

#include <dev/pci/pcivar.h>
#include <dev/pci/pcireg.h>

#include <machine/bus.h>
#include <machine/intr_machdep.h>
#include <machine/md_var.h>
#include <machine/pio.h>
#include <machine/resource.h>
#include <machine/rtas.h>

#include <vm/vm.h>
#include <vm/pmap.h>

#include <powerpc/pseries/plpar_iommu.h>

#include "pcib_if.h"
#include "iommu_if.h"

/*
 * Device interface.
 */
static int              rtaspci_probe(device_t);
static int              rtaspci_attach(device_t);

/*
 * pcib interface.
 */
static u_int32_t        rtaspci_read_config(device_t, u_int, u_int, u_int,
                            u_int, int);
static void             rtaspci_write_config(device_t, u_int, u_int, u_int,
                            u_int, u_int32_t, int);

/*
 * Driver methods.
 */
static device_method_t  rtaspci_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         rtaspci_probe),
        DEVMETHOD(device_attach,        rtaspci_attach),

        /* pcib interface */
        DEVMETHOD(pcib_read_config,     rtaspci_read_config),
        DEVMETHOD(pcib_write_config,    rtaspci_write_config),

        DEVMETHOD_END
};

struct rtaspci_softc {
        struct ofw_pci_softc    pci_sc;

        struct ofw_pci_register sc_pcir;

        cell_t                  read_pci_config, write_pci_config;
        cell_t                  ex_read_pci_config, ex_write_pci_config;
        int                     sc_extended_config;
};

DEFINE_CLASS_1(pcib, rtaspci_driver, rtaspci_methods,
    sizeof(struct rtaspci_softc), ofw_pcib_driver);
DRIVER_MODULE(rtaspci, ofwbus, rtaspci_driver, 0, 0);

static int
rtaspci_probe(device_t dev)
{
        const char      *type;

        if (!rtas_exists())
                return (ENXIO);

        type = ofw_bus_get_type(dev);

        if (OF_getproplen(ofw_bus_get_node(dev), "used-by-rtas") < 0)
                return (ENXIO);
        if (type == NULL || strcmp(type, "pci") != 0)
                return (ENXIO);

        device_set_desc(dev, "RTAS Host-PCI bridge");
        return (BUS_PROBE_GENERIC);
}

static int
rtaspci_attach(device_t dev)
{
        struct          rtaspci_softc *sc;

        sc = device_get_softc(dev);

        if (OF_getencprop(ofw_bus_get_node(dev), "reg", (pcell_t *)&sc->sc_pcir,
            sizeof(sc->sc_pcir)) == -1)
                return (ENXIO);

        sc->read_pci_config = rtas_token_lookup("read-pci-config");
        sc->write_pci_config = rtas_token_lookup("write-pci-config");
        sc->ex_read_pci_config = rtas_token_lookup("ibm,read-pci-config");
        sc->ex_write_pci_config = rtas_token_lookup("ibm,write-pci-config");

        sc->sc_extended_config = 0;
        OF_getencprop(ofw_bus_get_node(dev), "ibm,pci-config-space-type",
            &sc->sc_extended_config, sizeof(sc->sc_extended_config));

        return (ofw_pcib_attach(dev));
}

static uint32_t
rtaspci_read_config(device_t dev, u_int bus, u_int slot, u_int func, u_int reg,
    int width)
{
        struct rtaspci_softc *sc;
        uint32_t retval = 0xffffffff;
        uint32_t config_addr;
        int error, pcierror;

        sc = device_get_softc(dev);

        config_addr = ((bus & 0xff) << 16) | ((slot & 0x1f) << 11) |
            ((func & 0x7) << 8) | (reg & 0xff);
        if (sc->sc_extended_config)
                config_addr |= (reg & 0xf00) << 16;
                
        if (sc->ex_read_pci_config != -1)
                error = rtas_call_method(sc->ex_read_pci_config, 4, 2,
                    config_addr, sc->sc_pcir.phys_hi,
                    sc->sc_pcir.phys_mid, width, &pcierror, &retval);
        else
                error = rtas_call_method(sc->read_pci_config, 2, 2,
                    config_addr, width, &pcierror, &retval);

        /* Sign-extend output */
        switch (width) {
        case 1:
                retval = (int32_t)(int8_t)(retval);
                break;
        case 2:
                retval = (int32_t)(int16_t)(retval);
                break;
        }

        if (error < 0 || pcierror != 0)
                retval = 0xffffffff;

        return (retval);
}

static void
rtaspci_write_config(device_t dev, u_int bus, u_int slot, u_int func,
    u_int reg, uint32_t val, int width)
{
        struct rtaspci_softc *sc;
        uint32_t config_addr;
        int pcierror;

        sc = device_get_softc(dev);

        config_addr = ((bus & 0xff) << 16) | ((slot & 0x1f) << 11) |
            ((func & 0x7) << 8) | (reg & 0xff);
        if (sc->sc_extended_config)
                config_addr |= (reg & 0xf00) << 16;
                
        if (sc->ex_write_pci_config != -1)
                rtas_call_method(sc->ex_write_pci_config, 5, 1, config_addr,
                    sc->sc_pcir.phys_hi, sc->sc_pcir.phys_mid,
                    width, val, &pcierror);
        else
                rtas_call_method(sc->write_pci_config, 3, 1, config_addr,
                    width, val, &pcierror);
}