/* $NetBSD: ttwoga_pci.c,v 1.10 2021/06/25 03:49:47 thorpej Exp $ */

/*-
 * Copyright (c) 1999, 2000 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *
 * 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>                  /* RCS ID & Copyright macro defns */

__KERNEL_RCSID(0, "$NetBSD: ttwoga_pci.c,v 1.10 2021/06/25 03:49:47 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>

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

#include <alpha/pci/ttwogareg.h>
#include <alpha/pci/ttwogavar.h>

static int      ttwoga_bus_maxdevs(void *, int);
static pcireg_t ttwoga_conf_read(void *, pcitag_t, int);
static void     ttwoga_conf_write(void *, pcitag_t, int, pcireg_t);

static paddr_t  ttwoga_make_type0addr(int, int);

/*
 * The T2 has an annoying bug that can manifest itself while
 * probing for devices.  If a non-existent CBUS address is
 * accessed with a read, "a few" subsequent write cycles
 * will generate spurious memory errors.  We work around this
 * by tracking which CPU has the PCI configuration mutex and
 * "expect" machine checks on that CPU for the duraction of
 * the PCI configuration access routine.
 */

static kmutex_t ttwoga_conf_lock;
cpuid_t ttwoga_conf_cpu;                /* XXX core logic bug */

#define TTWOGA_CONF_LOCK()                                              \
do {                                                                    \
        mutex_enter(&ttwoga_conf_lock);                                 \
        ttwoga_conf_cpu = cpu_number();                                 \
} while (0)

#define TTWOGA_CONF_UNLOCK()                                            \
do {                                                                    \
        ttwoga_conf_cpu = (cpuid_t)-1;                                  \
        mutex_exit(&ttwoga_conf_lock);                                  \
} while (0)

void
ttwoga_pci_init(pci_chipset_tag_t pc, void *v)
{

        mutex_init(&ttwoga_conf_lock, MUTEX_DEFAULT, IPL_HIGH);

        pc->pc_conf_v = v;
        pc->pc_bus_maxdevs = ttwoga_bus_maxdevs;
        pc->pc_conf_read = ttwoga_conf_read;
        pc->pc_conf_write = ttwoga_conf_write;
}

static int
ttwoga_bus_maxdevs(void *cpv, int busno)
{
        /*
         * We have to drive the IDSEL directly on bus 0, so we are
         * limited to 9 devices there.
         */
        return busno == 0 ? 9 : 32;
}

static paddr_t
ttwoga_make_type0addr(int d, int f)
{
        KASSERT(d < 9);
        return PCI_CONF_TYPE0_IDSEL(d) | __SHIFTIN(f, PCI_CONF_TYPE1_FUNCTION);
}

static pcireg_t
ttwoga_conf_read(void *cpv, pcitag_t tag, int offset)
{
        struct ttwoga_config *tcp = cpv;
        pcireg_t *datap, data;
        int b, d, f, ba;
        paddr_t addr;
        uint64_t old_hae3;

        if ((unsigned int)offset >= PCI_CONF_SIZE)
                return (pcireg_t) -1;

        pci_decompose_tag(&tcp->tc_pc, tag, &b, &d, &f);

        addr = b ? tag : ttwoga_make_type0addr(d, f);

        TTWOGA_CONF_LOCK();

        alpha_mb();
        old_hae3 = T2GA(tcp, T2_HAE0_3) & ~HAE0_3_PCA;
        T2GA(tcp, T2_HAE0_3) =
            old_hae3 | ((b ? 1UL : 0UL) << HAE0_3_PCA_SHIFT);
        alpha_mb();
        alpha_mb();

        datap =
            (pcireg_t *)ALPHA_PHYS_TO_K0SEG(tcp->tc_sysmap->tsmap_conf_base |
            addr << 5UL |               /* address shift */
            (offset & ~0x03) << 5UL |   /* address shift */
            0x3 << 3UL);                /* 4-byte, size shift */
        data = (pcireg_t)-1;
        if (!(ba = badaddr(datap, sizeof *datap)))
                data = *datap;

        alpha_mb();
        T2GA(tcp, T2_HAE0_3) = old_hae3;
        alpha_mb();
        alpha_mb();

        alpha_pal_draina();
        alpha_mb();
        alpha_mb();

        TTWOGA_CONF_UNLOCK();

#if 0
        printf("ttwoga_conf_read: tag 0x%lx, reg 0x%x -> 0x%x @ %p%s\n",
            tag, offset, data, datap, ba ? " (badaddr)" : "");
#endif

        return (data);
}

static void
ttwoga_conf_write(void *cpv, pcitag_t tag, int offset, pcireg_t data)
{
        struct ttwoga_config *tcp = cpv;
        pcireg_t *datap;
        int b, d, f;
        paddr_t addr;
        uint64_t old_hae3;

        if ((unsigned int)offset >= PCI_CONF_SIZE)
                return;

        pci_decompose_tag(&tcp->tc_pc, tag, &b, &d, &f);

        addr = b ? tag : ttwoga_make_type0addr(d, f);

        TTWOGA_CONF_LOCK();

        alpha_mb();
        old_hae3 = T2GA(tcp, T2_HAE0_3) & ~HAE0_3_PCA;
        T2GA(tcp, T2_HAE0_3) =
            old_hae3 | ((b ? 1UL : 0UL) << HAE0_3_PCA_SHIFT);
        alpha_mb();
        alpha_mb();

        datap =
            (pcireg_t *)ALPHA_PHYS_TO_K0SEG(tcp->tc_sysmap->tsmap_conf_base |
            addr << 5UL |               /* address shift */
            (offset & ~0x03) << 5UL |   /* address shift */
            0x3 << 3UL);                /* 4-byte, size shift */

        alpha_mb();
        *datap = data;
        alpha_mb();
        alpha_mb();

        alpha_mb();
        T2GA(tcp, T2_HAE0_3) = old_hae3;
        alpha_mb();
        alpha_mb();

        TTWOGA_CONF_UNLOCK();

#if 0
        printf("ttwoga_conf_write: tag 0x%lx, reg 0x%x -> 0x%x @ %p\n",
            tag, offset, data, datap);
#endif
}