/* $NetBSD: acpi_pci.c,v 1.37 2022/10/14 22:10:15 jmcneill 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 1.37 2022/10/14 22:10:15 jmcneill 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/pci/pci_calls.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 *);

/*
* 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->sc_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->sc_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;

               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_bus_get_child_devhandle:
*
*      Implements the "pci-bus-get-child-devhandle" device call for
*      ACPI device handles
*/
static int
acpi_pci_bus_get_child_devhandle(device_t dev, devhandle_t call_handle, void *v)
{
       struct pci_bus_get_child_devhandle_args *args = v;
       struct acpi_devnode *ad;
       ACPI_HANDLE hdl;
       int b, d, f;
       u_int segment;

       segment = pci_get_segment(args->pc);

       pci_decompose_tag(args->pc, args->tag, &b, &d, &f);

       ad = acpi_pcidev_find(segment, b, d, f);

       if (ad != NULL && (hdl = ad->ad_handle) != NULL) {
               /* Found it! */
               args->devhandle = devhandle_from_acpi(call_handle, hdl);
               return 0;
       }

       return ENODEV;
}
ACPI_DEVICE_CALL_REGISTER(PCI_BUS_GET_CHILD_DEVHANDLE_STR,
                         acpi_pci_bus_get_child_devhandle)

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