/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2010 Hudson River Trading LLC
 * Written by: John H. Baldwin <jhb@FreeBSD.org>
 * 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.
 */

/*
 * This driver provides a pseudo-bus to enumerate the PCI buses
 * present on a system using a QPI chipset.  It creates a qpi0 bus that
 * is a child of nexus0 and then creates Host-PCI bridges as a
 * child of that.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: releng/12.0/sys/x86/pci/qpi.c 326263 2017-11-27 15:11:47Z pfg $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/systm.h>

#include <machine/cputypes.h>
#include <machine/md_var.h>
#include <x86/legacyvar.h>
#include <x86/pci_cfgreg.h>
#include <x86/specialreg.h>

#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>
#include <dev/pci/pcib_private.h>
#include "pcib_if.h"

struct qpi_device {
	int	qd_pcibus;
};

static MALLOC_DEFINE(M_QPI, "qpidrv", "qpi system device");

static void
qpi_identify(driver_t *driver, device_t parent)
{
	int do_qpi;

	/* Check CPUID to ensure this is an i7 CPU of some sort. */
	if (cpu_vendor_id != CPU_VENDOR_INTEL ||
	    CPUID_TO_FAMILY(cpu_id) != 0x6)
		return;

	/* Only discover buses with configuration devices if allowed by user */
	do_qpi = 0;
	TUNABLE_INT_FETCH("hw.attach_intel_csr_pci", &do_qpi);
	if (!do_qpi)
		return;

	/* PCI config register access is required. */
	if (pci_cfgregopen() == 0)
		return;

	/* Add a qpi bus device. */
	if (BUS_ADD_CHILD(parent, 20, "qpi", -1) == NULL)
		panic("Failed to add qpi bus");
}

static int
qpi_probe(device_t dev)
{

	device_set_desc(dev, "QPI system bus");
	return (BUS_PROBE_SPECIFIC);
}

/*
 * Look for a PCI bus with the specified bus address.  If one is found,
 * add a pcib device and return 0.  Otherwise, return an error code.
 */
static int
qpi_probe_pcib(device_t dev, int bus)
{
	struct qpi_device *qdev;
	device_t child;
	uint32_t devid;
	int s;

	/*
	 * If a PCI bus already exists for this bus number, then
	 * fail.
	 */
	if (pci_find_bsf(bus, 0, 0) != NULL)
		return (EEXIST);

	/*
	 * Attempt to read the device id for every slot, function 0 on
	 * the bus.  If all read values are 0xffffffff this means that
	 * the bus is not present.
	 */
	for (s = 0; s <= PCI_SLOTMAX; s++) {
		devid = pci_cfgregread(bus, s, 0, PCIR_DEVVENDOR, 4);
		if (devid != 0xffffffff)
			break;
	}
	if (devid == 0xffffffff)
		return (ENOENT);

	if ((devid & 0xffff) != 0x8086) {
		if (bootverbose)
			device_printf(dev,
			    "Device at pci%d.%d.0 has non-Intel vendor 0x%x\n",
			    bus, s, devid & 0xffff);
		return (ENXIO);
	}

	child = BUS_ADD_CHILD(dev, 0, "pcib", -1);
	if (child == NULL)
		panic("%s: failed to add pci bus %d", device_get_nameunit(dev),
		    bus);
	qdev = malloc(sizeof(struct qpi_device), M_QPI, M_WAITOK);
	qdev->qd_pcibus = bus;
	device_set_ivars(child, qdev);
	return (0);
}

static int
qpi_attach(device_t dev)
{
	int bus;

	/*
	 * Each processor socket has a dedicated PCI bus, sometimes
	 * not enumerated by ACPI.  Probe all unattached buses from 0
	 * to 255.
	 */
	for (bus = PCI_BUSMAX; bus >= 0; bus--)
		qpi_probe_pcib(dev, bus);

	return (bus_generic_attach(dev));
}

static int
qpi_print_child(device_t bus, device_t child)
{
	struct qpi_device *qdev;
	int retval = 0;

	qdev = device_get_ivars(child);
	retval += bus_print_child_header(bus, child);
	if (qdev->qd_pcibus != -1)
		retval += printf(" pcibus %d", qdev->qd_pcibus);
	retval += bus_print_child_footer(bus, child);

	return (retval);
}

static int
qpi_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
{
	struct qpi_device *qdev;

	qdev = device_get_ivars(child);
	switch (which) {
	case PCIB_IVAR_BUS:
		*result = qdev->qd_pcibus;
		break;
	default:
		return (ENOENT);
	}
	return (0);
}

static device_method_t qpi_methods[] = {
	/* Device interface */
	DEVMETHOD(device_identify,	qpi_identify),
	DEVMETHOD(device_probe,		qpi_probe),
	DEVMETHOD(device_attach,	qpi_attach),
	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
	DEVMETHOD(device_suspend,	bus_generic_suspend),
	DEVMETHOD(device_resume,	bus_generic_resume),

	/* Bus interface */
	DEVMETHOD(bus_print_child,	qpi_print_child),
	DEVMETHOD(bus_add_child,	bus_generic_add_child),
	DEVMETHOD(bus_read_ivar,	qpi_read_ivar),
	DEVMETHOD(bus_alloc_resource,	bus_generic_alloc_resource),
	DEVMETHOD(bus_release_resource,	bus_generic_release_resource),
	DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
	DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
	DEVMETHOD(bus_setup_intr,	bus_generic_setup_intr),
	DEVMETHOD(bus_teardown_intr,	bus_generic_teardown_intr),

	{ 0, 0 }
};

static devclass_t qpi_devclass;

DEFINE_CLASS_0(qpi, qpi_driver, qpi_methods, 0);
DRIVER_MODULE(qpi, nexus, qpi_driver, qpi_devclass, 0, 0);

static int
qpi_pcib_probe(device_t dev)
{

	device_set_desc(dev, "QPI Host-PCI bridge");
	return (BUS_PROBE_SPECIFIC);
}

static int
qpi_pcib_attach(device_t dev)
{

	device_add_child(dev, "pci", -1);
	return (bus_generic_attach(dev));
}

static int
qpi_pcib_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
{

	switch (which) {
	case PCIB_IVAR_DOMAIN:
		*result = 0;
		return (0);
	case PCIB_IVAR_BUS:
		*result = pcib_get_bus(dev);
		return (0);
	default:
		return (ENOENT);
	}
}

#if defined(NEW_PCIB) && defined(PCI_RES_BUS)
static struct resource *
qpi_pcib_alloc_resource(device_t dev, device_t child, int type, int *rid,
    rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{

	if (type == PCI_RES_BUS)
		return (pci_domain_alloc_bus(0, child, rid, start, end, count,
		    flags));
	return (bus_generic_alloc_resource(dev, child, type, rid, start, end,
	    count, flags));
}
#endif

static int
qpi_pcib_map_msi(device_t pcib, device_t dev, int irq, uint64_t *addr,
    uint32_t *data)
{
	device_t bus;

	bus = device_get_parent(pcib);
	return (PCIB_MAP_MSI(device_get_parent(bus), dev, irq, addr, data));
}

static device_method_t qpi_pcib_methods[] = {
	/* Device interface */
	DEVMETHOD(device_probe,		qpi_pcib_probe),
	DEVMETHOD(device_attach,	qpi_pcib_attach),
	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
	DEVMETHOD(device_suspend,	bus_generic_suspend),
	DEVMETHOD(device_resume,	bus_generic_resume),

	/* Bus interface */
	DEVMETHOD(bus_read_ivar,	qpi_pcib_read_ivar),
#if defined(NEW_PCIB) && defined(PCI_RES_BUS)
	DEVMETHOD(bus_alloc_resource,	qpi_pcib_alloc_resource),
	DEVMETHOD(bus_adjust_resource,	legacy_pcib_adjust_resource),
	DEVMETHOD(bus_release_resource,	legacy_pcib_release_resource),
#else
	DEVMETHOD(bus_alloc_resource,	bus_generic_alloc_resource),
	DEVMETHOD(bus_release_resource,	bus_generic_release_resource),
#endif
	DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
	DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
	DEVMETHOD(bus_setup_intr,	bus_generic_setup_intr),
	DEVMETHOD(bus_teardown_intr,	bus_generic_teardown_intr),

	/* pcib interface */
	DEVMETHOD(pcib_maxslots,	pcib_maxslots),
	DEVMETHOD(pcib_read_config,	legacy_pcib_read_config),
	DEVMETHOD(pcib_write_config,	legacy_pcib_write_config),
	DEVMETHOD(pcib_alloc_msi,	legacy_pcib_alloc_msi),
	DEVMETHOD(pcib_release_msi,	pcib_release_msi),
	DEVMETHOD(pcib_alloc_msix,	legacy_pcib_alloc_msix),
	DEVMETHOD(pcib_release_msix,	pcib_release_msix),
	DEVMETHOD(pcib_map_msi,		qpi_pcib_map_msi),

	DEVMETHOD_END
};

static devclass_t qpi_pcib_devclass;

DEFINE_CLASS_0(pcib, qpi_pcib_driver, qpi_pcib_methods, 0);
DRIVER_MODULE(pcib, qpi, qpi_pcib_driver, qpi_pcib_devclass, 0, 0);
