/* $NetBSD: acpi_pci.c,v 1.30 2021/01/14 14:37:17 thorpej Exp $ */

/*
 * Copyright (c) 2009, 2010 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Christoph Egger and Gregoire Sutre.
 *
 * 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. 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: acpi_pci.c,v 1.30 2021/01/14 14:37:17 thorpej Exp $");

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

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

#include <dev/acpi/acpireg.h>
#include <dev/acpi/acpivar.h>
#include <dev/acpi/acpi_pci.h>

#include "locators.h"

#define _COMPONENT	  ACPI_BUS_COMPONENT
ACPI_MODULE_NAME	  ("acpi_pci")

#define ACPI_HILODWORD(x) ACPI_HIWORD(ACPI_LODWORD((x)))
#define ACPI_LOLODWORD(x) ACPI_LOWORD(ACPI_LODWORD((x)))

static ACPI_STATUS	  acpi_pcidev_pciroot_bus_callback(ACPI_RESOURCE *,
							   void *);

/*
 * UUID for _DSM control method, from PCI Firmware Specification.
 */
static UINT8 acpi_pci_dsm_uuid[ACPI_UUID_LENGTH] = {
	0xd0, 0x37, 0xc9, 0xe5, 0x53, 0x35, 0x7a, 0x4d,
	0x91, 0x17, 0xea, 0x4d, 0x19, 0xc3, 0x43, 0x4d
};

/*
 * Regarding PCI Segment Groups (ACPI 4.0, p. 277):
 *
 * "The optional _SEG object is located under a PCI host bridge and
 *  evaluates to an integer that describes the PCI Segment Group (see PCI
 *  Firmware Specification v3.0)."
 *
 * "PCI Segment Group is purely a software concept managed by system
 *  firmware and used by OSPM. It is a logical collection of PCI buses
 *  (or bus segments). It is a way to logically group the PCI bus segments
 *  and PCI Express Hierarchies. _SEG is a level higher than _BBN."
 *
 * "PCI Segment Group supports more than 256 buses in a system by allowing
 *  the reuse of the PCI bus numbers.  Within each PCI Segment Group, the bus
 *  numbers for the PCI buses must be unique. PCI buses in different PCI
 *  Segment Group are permitted to have the same bus number."
 */

/*
 * Regarding PCI Base Bus Numbers (ACPI 4.0, p. 277):
 *
 * "For multi-root PCI platforms, the _BBN object evaluates to the PCI bus
 *  number that the BIOS assigns.  This is needed to access a PCI_Config
 *  operation region for the specified bus.  The _BBN object is located under
 *  a PCI host bridge and must be unique for every host bridge within a
 *  segment since it is the PCI bus number."
 *
 * Moreover, the ACPI FAQ (http://www.acpi.info/acpi_faq.htm) says:
 *
 * "For a multiple root bus machine, _BBN is required for each bus.  _BBN
 *  should provide the bus number assigned to this bus by the BIOS at boot
 *  time."
 */

/*
 * acpi_pcidev_pciroot_bus:
 *
 *	Derive the PCI bus number of a PCI root bridge from its resources.
 *	If successful, return AE_OK and fill *busp.  Otherwise, return an
 *	exception code and leave *busp unchanged.
 */
ACPI_STATUS
acpi_pcidev_pciroot_bus(ACPI_HANDLE handle, uint16_t *busp)
{
	ACPI_STATUS rv;
	int32_t bus;

	bus = -1;

	/*
	 * XXX:	Use the ACPI resource parsing functions (acpi_resource.c)
	 *	once bus number ranges have been implemented there.
	 */
	rv = AcpiWalkResources(handle, "_CRS",
	    acpi_pcidev_pciroot_bus_callback, &bus);

	if (ACPI_FAILURE(rv))
		return rv;

	if (bus == -1)
		return AE_NOT_EXIST;

	/* Here it holds that 0 <= bus <= 0xFFFF. */
	*busp = (uint16_t)bus;

	return rv;
}

static ACPI_STATUS
acpi_pcidev_pciroot_bus_callback(ACPI_RESOURCE *res, void *context)
{
	ACPI_RESOURCE_ADDRESS64 addr64;
	int32_t *bus = context;

	/* Always continue the walk by returning AE_OK. */
	if ((res->Type != ACPI_RESOURCE_TYPE_ADDRESS16) &&
	    (res->Type != ACPI_RESOURCE_TYPE_ADDRESS32) &&
	    (res->Type != ACPI_RESOURCE_TYPE_ADDRESS64))
		return AE_OK;

	if (ACPI_FAILURE(AcpiResourceToAddress64(res, &addr64)))
		return AE_OK;

	if (addr64.ResourceType != ACPI_BUS_NUMBER_RANGE)
		return AE_OK;

	if (*bus != -1)
		return AE_ALREADY_EXISTS;

	if (addr64.Address.Minimum > 0xFFFF)
		return AE_BAD_DATA;

	*bus = (int32_t)addr64.Address.Minimum;

	return AE_OK;
}

/*
 * acpi_pcidev_scan:
 *
 *	Scan the ACPI device tree for PCI devices.  A node is detected as a
 *	PCI device if it has an ancestor that is a PCI root bridge and such
 *	that all intermediate nodes are PCI-to-PCI bridges.  Depth-first
 *	recursive implementation.
 *
 *	PCI root bridges do not necessarily contain an _ADR, since they already
 *	contain an _HID (ACPI 4.0a, p. 197).  However we require an _ADR for
 *	all non-root PCI devices.
 */
ACPI_STATUS
acpi_pcidev_scan(struct acpi_devnode *ad)
{
	struct acpi_devnode *child;
	struct acpi_pci_info *ap;
	ACPI_INTEGER val;
	ACPI_STATUS rv;

	ad->ad_pciinfo = NULL;

	/*
	 * We attach PCI information only to devices that are present,
	 * enabled, and functioning properly.
	 * Note: there is a possible race condition, because _STA may
	 * have changed since ad->ad_devinfo->CurrentStatus was set.
	 */
	if (ad->ad_devinfo->Type != ACPI_TYPE_DEVICE)
		goto rec;

	if (!acpi_device_present(ad->ad_handle))
		goto rec;

	if (ad->ad_devinfo->Flags & ACPI_PCI_ROOT_BRIDGE) {

		ap = kmem_zalloc(sizeof(*ap), KM_SLEEP);

		/*
		 * If no _SEG exist, all PCI bus segments are assumed
		 * to be in the PCI segment group 0 (ACPI 4.0, p. 277).
		 * The segment group number is conveyed in the lower
		 * 16 bits of _SEG (the other bits are all reserved).
		 */
		rv = acpi_eval_integer(ad->ad_handle, "_SEG", &val);

		if (ACPI_SUCCESS(rv))
			ap->ap_segment = ACPI_LOWORD(val);

		/* Try to get downstream bus number using _CRS first. */
		rv = acpi_pcidev_pciroot_bus(ad->ad_handle, &ap->ap_downbus);

		if (ACPI_FAILURE(rv)) {
			rv = acpi_eval_integer(ad->ad_handle, "_BBN", &val);

			if (ACPI_SUCCESS(rv))
				ap->ap_downbus = ACPI_LOWORD(val);
		}

		if (ap->ap_downbus > 255) {
			aprint_error_dev(ad->ad_root,
			    "invalid PCI downstream bus for %s\n", ad->ad_name);
			kmem_free(ap, sizeof(*ap));
			goto rec;
		}

		ap->ap_flags |= ACPI_PCI_INFO_BRIDGE;

		ap->ap_pc = acpi_get_pci_chipset_tag(acpi_softc, ap->ap_segment, ap->ap_downbus);

		/*
		 * This ACPI node denotes a PCI root bridge, but it may also
		 * denote a PCI device on the bridge's downstream bus segment.
		 */
		if (ad->ad_devinfo->Valid & ACPI_VALID_ADR) {
			ap->ap_bus = ap->ap_downbus;
			ap->ap_device =
			    ACPI_HILODWORD(ad->ad_devinfo->Address);
			ap->ap_function =
			    ACPI_LOLODWORD(ad->ad_devinfo->Address);

			if (ap->ap_device > 31 ||
			    (ap->ap_function > 7 && ap->ap_function != 0xFFFF))
				aprint_error_dev(ad->ad_root,
				    "invalid PCI address for %s\n", ad->ad_name);
			else
				ap->ap_flags |= ACPI_PCI_INFO_DEVICE;
		}

		ad->ad_pciinfo = ap;

		goto rec;
	}

	if ((ad->ad_parent != NULL) &&
	    (ad->ad_parent->ad_pciinfo != NULL) &&
	    (ad->ad_parent->ad_pciinfo->ap_flags & ACPI_PCI_INFO_BRIDGE) &&
	    (ad->ad_devinfo->Valid & ACPI_VALID_ADR)) {

		/*
		 * Our parent is a PCI root bridge or a PCI-to-PCI
		 * bridge. We have the same PCI segment number, and
		 * our bus number is its downstream bus number.
		 */
		ap = kmem_zalloc(sizeof(*ap), KM_SLEEP);

		ap->ap_pc = ad->ad_parent->ad_pciinfo->ap_pc;
		ap->ap_segment = ad->ad_parent->ad_pciinfo->ap_segment;
		ap->ap_bus = ad->ad_parent->ad_pciinfo->ap_downbus;

		ap->ap_device = ACPI_HILODWORD(ad->ad_devinfo->Address);
		ap->ap_function = ACPI_LOLODWORD(ad->ad_devinfo->Address);

		if (ap->ap_device > 31 ||
		    (ap->ap_function > 7 && ap->ap_function != 0xFFFF)) {
			aprint_error_dev(ad->ad_root,
			    "invalid PCI address for %s\n", ad->ad_name);
			kmem_free(ap, sizeof(*ap));
			goto rec;
		}

		ap->ap_flags |= ACPI_PCI_INFO_DEVICE;

		if (ap->ap_function == 0xFFFF) {
			/*
			 * Assume that this device is not a PCI-to-PCI bridge.
			 * XXX: Do we need to be smarter?
			 */
		} else {
			/*
			 * Check whether this device is a PCI-to-PCI
			 * bridge and get its secondary bus number.
			 */
			rv = acpi_pcidev_ppb_downbus(
			    ad->ad_parent->ad_pciinfo->ap_pc,
			    ap->ap_segment, ap->ap_bus, ap->ap_device,
			    ap->ap_function, &ap->ap_downbus);

			if (ACPI_SUCCESS(rv))
				ap->ap_flags |= ACPI_PCI_INFO_BRIDGE;
		}

		ad->ad_pciinfo = ap;

		goto rec;
	}

rec:
	SIMPLEQ_FOREACH(child, &ad->ad_child_head, ad_child_list) {
		rv = acpi_pcidev_scan(child);

		if (ACPI_FAILURE(rv))
			return rv;
	}

	return AE_OK;
}

/*
 * acpi_pcidev_ppb_downbus:
 *
 *	Retrieve the secondary bus number of the PCI-to-PCI bridge having the
 *	given PCI id.  If successful, return AE_OK and fill *downbus.
 *	Otherwise, return an exception code and leave *downbus unchanged.
 *
 * XXX	Need to deal with PCI segment groups (see also acpica/OsdHardware.c).
 */
ACPI_STATUS
acpi_pcidev_ppb_downbus(pci_chipset_tag_t pc, uint16_t segment, uint16_t bus,
    uint16_t device, uint16_t function, uint16_t *downbus)
{
	pcitag_t tag;
	pcireg_t val;

	if (bus > 255 || device > 31 || function > 7)
		return AE_BAD_PARAMETER;

	tag = pci_make_tag(pc, bus, device, function);

	/* Check that this device exists. */
	val = pci_conf_read(pc, tag, PCI_ID_REG);

	if (PCI_VENDOR(val) == PCI_VENDOR_INVALID ||
	    PCI_VENDOR(val) == 0)
		return AE_NOT_EXIST;

	/* Check that this device is a PCI-to-PCI bridge. */
	val = pci_conf_read(pc, tag, PCI_BHLC_REG);

	if (PCI_HDRTYPE_TYPE(val) != PCI_HDRTYPE_PPB)
		return AE_TYPE;

	/* This is a PCI-to-PCI bridge.  Get its secondary bus#. */
	val = pci_conf_read(pc, tag, PCI_BRIDGE_BUS_REG);
	*downbus = PCI_BRIDGE_BUS_NUM_SECONDARY(val);

	return AE_OK;
}

/*
 * acpi_pcidev_find:
 *
 *      Finds a PCI device in the ACPI name space.
 *
 *      Returns an ACPI device node on success and NULL on failure.
 */
struct acpi_devnode *
acpi_pcidev_find(uint16_t segment, uint16_t bus,
    uint16_t device, uint16_t function)
{
	struct acpi_softc *sc = acpi_softc;
	struct acpi_devnode *ad;

	if (sc == NULL)
		return NULL;

	SIMPLEQ_FOREACH(ad, &sc->ad_head, ad_list) {

		if (ad->ad_pciinfo != NULL &&
		    (ad->ad_pciinfo->ap_flags & ACPI_PCI_INFO_DEVICE) &&
		    ad->ad_pciinfo->ap_segment == segment &&
		    ad->ad_pciinfo->ap_bus == bus &&
		    ad->ad_pciinfo->ap_device == device &&
		    ad->ad_pciinfo->ap_function == function)
			return ad;
	}

	return NULL;
}

/*
 * acpi_pcidev_get_tag:
 *
 *	Returns a PCI chipset tag for a PCI device in the ACPI name space.
 */
pci_chipset_tag_t
acpi_pcidev_get_tag(uint16_t segment, uint16_t bus,
    uint16_t device, uint16_t function)
{
	struct acpi_devnode *ad;

	ad = acpi_pcidev_find(segment, bus, device, function);
	if (ad == NULL || ad->ad_pciinfo == NULL)
		return NULL;

	return ad->ad_pciinfo->ap_pc;
}

/*
 * acpi_pciroot_find:
 *
 *	Finds a PCI root bridge in the ACPI name space.
 *
 *	Returns an ACPI device node on success and NULL on failure.
 */
struct acpi_devnode *
acpi_pciroot_find(uint16_t segment, uint16_t bus)
{
	struct acpi_softc *sc = acpi_softc;
	struct acpi_devnode *ad;

	if (sc == NULL)
		return NULL;

	SIMPLEQ_FOREACH(ad, &sc->ad_head, ad_list) {

		if (ad->ad_pciinfo != NULL &&
		    (ad->ad_pciinfo->ap_flags & ACPI_PCI_INFO_BRIDGE) &&
		    ad->ad_pciinfo->ap_segment == segment &&
		    ad->ad_pciinfo->ap_bus == bus)
			return ad;
	}

	return NULL;
}

/*
 * acpi_pcidev_find_dev:
 *
 *	Returns the device corresponding to the given PCI info, or NULL
 *	if it doesn't exist.
 */
device_t
acpi_pcidev_find_dev(struct acpi_devnode *ad)
{
	struct acpi_pci_info *ap;
	struct pci_softc *pci;
	device_t dv, pr;
	deviter_t di;

	if (ad == NULL)
		return NULL;

	if (ad->ad_pciinfo == NULL)
		return NULL;

	ap = ad->ad_pciinfo;

	if (ap->ap_function == 0xFFFF)
		return NULL;

	for (dv = deviter_first(&di, DEVITER_F_ROOT_FIRST);
	     dv != NULL; dv = deviter_next(&di)) {

		pr = device_parent(dv);

		if (pr == NULL || device_is_a(pr, "pci") != true)
			continue;

		if (dv->dv_locators == NULL)	/* This should not happen. */
			continue;

		pci = device_private(pr);

		if (pci->sc_bus == ap->ap_bus &&
		    device_locator(dv, PCICF_DEV) == ap->ap_device &&
		    device_locator(dv, PCICF_FUNCTION) == ap->ap_function)
			break;
	}

	deviter_release(&di);

	return dv;
}

/*
 * acpi_pci_ignore_boot_config:
 *
 *	Returns 1 if the operating system may ignore the boot configuration
 *	of PCI resources.
 */
ACPI_INTEGER
acpi_pci_ignore_boot_config(ACPI_HANDLE handle)
{
	ACPI_OBJECT *pobj = NULL;
	ACPI_INTEGER ret;

	/*
	 * This one is a little confusing, but the result of
	 * evaluating _DSM #5 is:
	 *
	 * 0: The operating system may not ignore the boot configuration
	 *    of PCI resources.
	 *
	 * 1: The operating system may ignore the boot configuration of
	 *    PCI resources, and reconfigure or rebalance these resources
	 *    in the hierarchy as required.
	 */

	if (ACPI_FAILURE(acpi_dsm(handle, acpi_pci_dsm_uuid,
				  1, 5, NULL, &pobj))) {
		/*
		 * In the absence of _DSM #5, we may assume that the
		 * boot config can be ignored.
		 */
		return 1;
	}

	/*
	 * ...and we default to "may ignore" in the event that the
	 * method returns nonsense.
	 */
	ret = 1;

	if (pobj != NULL) {
		switch (pobj->Type) {
		case ACPI_TYPE_INTEGER:
			ret = pobj->Integer.Value;
			break;

		case ACPI_TYPE_PACKAGE:
			if (pobj->Package.Count == 1 &&
			    pobj->Package.Elements[0].Type == ACPI_TYPE_INTEGER)
				ret = pobj->Package.Elements[0].Integer.Value;
			break;
		}
		ACPI_FREE(pobj);
	}

	return ret;
}