/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright 2003 by Peter Grehan. 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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/proc.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 <powerpc/powermac/gracklevar.h>

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

#include "pcib_if.h"

/*
 * Device interface.
 */
static int              grackle_probe(device_t);
static int              grackle_attach(device_t);

/*
 * pcib interface.
 */
static u_int32_t        grackle_read_config(device_t, u_int, u_int, u_int,
                            u_int, int);
static void             grackle_write_config(device_t, u_int, u_int, u_int,
                            u_int, u_int32_t, int);

/*
 * Local routines.
 */
static int              grackle_enable_config(struct grackle_softc *, u_int,
                            u_int, u_int, u_int);
static void             grackle_disable_config(struct grackle_softc *);
static int              badaddr(void *, size_t);

/*
 * Driver methods.
 */
static device_method_t  grackle_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         grackle_probe),
        DEVMETHOD(device_attach,        grackle_attach),

        /* pcib interface */
        DEVMETHOD(pcib_read_config,     grackle_read_config),
        DEVMETHOD(pcib_write_config,    grackle_write_config),

        DEVMETHOD_END
};

DEFINE_CLASS_1(pcib, grackle_driver, grackle_methods,
    sizeof(struct grackle_softc), ofw_pcib_driver);
DRIVER_MODULE(grackle, ofwbus, grackle_driver, 0, 0);

static int
grackle_probe(device_t dev)
{
        const char      *type, *compatible;

        type = ofw_bus_get_type(dev);
        compatible = ofw_bus_get_compat(dev);

        if (type == NULL || compatible == NULL)
                return (ENXIO);

        if (strcmp(type, "pci") != 0 || strcmp(compatible, "grackle") != 0)
                return (ENXIO);

        device_set_desc(dev, "MPC106 (Grackle) Host-PCI bridge");
        return (0);
}

static int
grackle_attach(device_t dev)
{
        struct          grackle_softc *sc;

        sc = device_get_softc(dev);

        /*
         * The Grackle PCI config addr/data registers are actually in
         * PCI space, but since they are needed to actually probe the
         * PCI bus, use the fact that they are also available directly
         * on the processor bus and map them
         */
        sc->sc_addr = (vm_offset_t)pmap_mapdev(GRACKLE_ADDR, PAGE_SIZE);
        sc->sc_data = (vm_offset_t)pmap_mapdev(GRACKLE_DATA, PAGE_SIZE);

        return (ofw_pcib_attach(dev));
}

static u_int32_t
grackle_read_config(device_t dev, u_int bus, u_int slot, u_int func, u_int reg,
    int width)
{
        struct          grackle_softc *sc;
        vm_offset_t     caoff;
        u_int32_t       retval = 0xffffffff;

        sc = device_get_softc(dev);
        caoff = sc->sc_data + (reg & 0x03);

        if (grackle_enable_config(sc, bus, slot, func, reg) != 0) {
                /*
                 * Config probes to non-existent devices on the
                 * secondary bus generates machine checks. Be sure
                 * to catch these.
                 */
                if (bus > 0) {
                  if (badaddr((void *)sc->sc_data, 4)) {
                          return (retval);
                  }
                }

                switch (width) {
                case 1:
                        retval = (in8rb(caoff));
                        break;
                case 2:
                        retval = (in16rb(caoff));
                        break;
                case 4:
                        retval = (in32rb(caoff));
                        break;
                }
        }
        grackle_disable_config(sc);

        return (retval);
}

static void
grackle_write_config(device_t dev, u_int bus, u_int slot, u_int func,
    u_int reg, u_int32_t val, int width)
{
        struct          grackle_softc *sc;
        vm_offset_t     caoff;

        sc = device_get_softc(dev);
        caoff = sc->sc_data + (reg & 0x03);

        if (grackle_enable_config(sc, bus, slot, func, reg)) {
                switch (width) {
                case 1:
                        out8rb(caoff, val);
                        (void)in8rb(caoff);
                        break;
                case 2:
                        out16rb(caoff, val);
                        (void)in16rb(caoff);
                        break;
                case 4:
                        out32rb(caoff, val);
                        (void)in32rb(caoff);
                        break;
                }
        }
        grackle_disable_config(sc);
}

static int
grackle_enable_config(struct grackle_softc *sc, u_int bus, u_int slot,
    u_int func, u_int reg)
{
        u_int32_t       cfgval;

        /*
         * Unlike UniNorth, the format of the config word is the same
         * for local (0) and remote busses.
         */
        cfgval = (bus << 16) | (slot << 11) | (func << 8) | (reg & 0xFC)
            | GRACKLE_CFG_ENABLE;

        out32rb(sc->sc_addr, cfgval);
        (void) in32rb(sc->sc_addr);

        return (1);
}

static void
grackle_disable_config(struct grackle_softc *sc)
{
        /*
         * Clear the GRACKLE_CFG_ENABLE bit to prevent stray
         * accesses from causing config cycles
         */
        out32rb(sc->sc_addr, 0);
}

static int
badaddr(void *addr, size_t size)
{
        struct thread   *td;
        jmp_buf         env, *oldfaultbuf;

        /* Get rid of any stale machine checks that have been waiting.  */
        __asm __volatile ("sync; isync");

        td = curthread;

        oldfaultbuf = td->td_pcb->pcb_onfault;
        td->td_pcb->pcb_onfault = &env;
        if (setjmp(env)) {
                td->td_pcb->pcb_onfault = oldfaultbuf;
                __asm __volatile ("sync");
                return 1;
        }

        __asm __volatile ("sync");

        switch (size) {
        case 1:
                (void)*(volatile int8_t *)addr;
                break;
        case 2:
                (void)*(volatile int16_t *)addr;
                break;
        case 4:
                (void)*(volatile int32_t *)addr;
                break;
        default:
                panic("badaddr: invalid size (%zd)", size);
        }

        /* Make sure we took the machine check, if we caused one. */
        __asm __volatile ("sync; isync");

        td->td_pcb->pcb_onfault = oldfaultbuf;
        __asm __volatile ("sync");      /* To be sure. */

        return (0);
}

/*
 * Driver to swallow Grackle host bridges from the PCI bus side.
 */
static int
grackle_hb_probe(device_t dev)
{

        if (pci_get_devid(dev) == 0x00021057) {
                device_set_desc(dev, "Grackle Host to PCI bridge");
                device_quiet(dev);
                return (0);
        }

        return (ENXIO);
}

static int
grackle_hb_attach(device_t dev)
{

        return (0);
}

static device_method_t grackle_hb_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         grackle_hb_probe),
        DEVMETHOD(device_attach,        grackle_hb_attach),
        { 0, 0 }
};

static driver_t grackle_hb_driver = {
        "grackle_hb",
        grackle_hb_methods,
        1,
};

DRIVER_MODULE(grackle_hb, pci, grackle_hb_driver, 0, 0);