LXR linux/drivers/acpi/pci

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  pci_slot.c - ACPI PCI Slot Driver
   4 *
   5 *  The code here is heavily leveraged from the acpiphp module.
   6 *  Thanks to Matthew Wilcox <matthew@wil.cx> for much guidance.
   7 *  Thanks to Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> for code
   8 *  review and fixes.
   9 *
  10 *  Copyright (C) 2007-2008 Hewlett-Packard Development Company, L.P.
  11 *      Alex Chiang <achiang@hp.com>
  12 *
  13 *  Copyright (C) 2013 Huawei Tech. Co., Ltd.
  14 *      Jiang Liu <jiang.liu@huawei.com>
  15 */
  16
  17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18
  19#include <linux/kernel.h>
  20#include <linux/init.h>
  21#include <linux/slab.h>
  22#include <linux/types.h>
  23#include <linux/list.h>
  24#include <linux/pci.h>
  25#include <linux/acpi.h>
  26#include <linux/dmi.h>
  27#include <linux/pci-acpi.h>
  28
  29static int check_sta_before_sun;
  30
  31#define SLOT_NAME_SIZE 21               /* Inspired by #define in acpiphp.h */
  32
  33struct acpi_pci_slot {
  34        struct pci_slot *pci_slot;      /* corresponding pci_slot */
  35        struct list_head list;          /* node in the list of slots */
  36};
  37
  38static LIST_HEAD(slot_list);
  39static DEFINE_MUTEX(slot_list_lock);
  40
  41static int
  42check_slot(acpi_handle handle, unsigned long long *sun)
  43{
  44        int device = -1;
  45        unsigned long long adr, sta;
  46        acpi_status status;
  47        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  48
  49        acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
  50        pr_debug("Checking slot on path: %s\n", (char *)buffer.pointer);
  51
  52        if (check_sta_before_sun) {
  53                /* If SxFy doesn't have _STA, we just assume it's there */
  54                status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
  55                if (ACPI_SUCCESS(status) && !(sta & ACPI_STA_DEVICE_PRESENT))
  56                        goto out;
  57        }
  58
  59        status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
  60        if (ACPI_FAILURE(status)) {
  61                pr_debug("_ADR returned %d on %s\n",
  62                         status, (char *)buffer.pointer);
  63                goto out;
  64        }
  65
  66        /* No _SUN == not a slot == bail */
  67        status = acpi_evaluate_integer(handle, "_SUN", NULL, sun);
  68        if (ACPI_FAILURE(status)) {
  69                pr_debug("_SUN returned %d on %s\n",
  70                         status, (char *)buffer.pointer);
  71                goto out;
  72        }
  73
  74        device = (adr >> 16) & 0xffff;
  75out:
  76        kfree(buffer.pointer);
  77        return device;
  78}
  79
  80/*
  81 * Check whether handle has an associated slot and create PCI slot if it has.
  82 */
  83static acpi_status
  84register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
  85{
  86        int device;
  87        unsigned long long sun;
  88        char name[SLOT_NAME_SIZE];
  89        struct acpi_pci_slot *slot;
  90        struct pci_slot *pci_slot;
  91        struct pci_bus *pci_bus = context;
  92
  93        device = check_slot(handle, &sun);
  94        if (device < 0)
  95                return AE_OK;
  96
  97        /*
  98         * There may be multiple PCI functions associated with the same slot.
  99         * Check whether PCI slot has already been created for this PCI device.
 100         */
 101        list_for_each_entry(slot, &slot_list, list) {
 102                pci_slot = slot->pci_slot;
 103                if (pci_slot->bus == pci_bus && pci_slot->number == device)
 104                        return AE_OK;
 105        }
 106
 107        slot = kmalloc(sizeof(*slot), GFP_KERNEL);
 108        if (!slot)
 109                return AE_OK;
 110
 111        snprintf(name, sizeof(name), "%llu", sun);
 112        pci_slot = pci_create_slot(pci_bus, device, name, NULL);
 113        if (IS_ERR(pci_slot)) {
 114                pr_err("pci_create_slot returned %ld\n", PTR_ERR(pci_slot));
 115                kfree(slot);
 116                return AE_OK;
 117        }
 118
 119        slot->pci_slot = pci_slot;
 120        list_add(&slot->list, &slot_list);
 121
 122        get_device(&pci_bus->dev);
 123
 124        pr_debug("%p, pci_bus: %x, device: %d, name: %s\n",
 125                 pci_slot, pci_bus->number, device, name);
 126
 127        return AE_OK;
 128}
 129
 130void acpi_pci_slot_enumerate(struct pci_bus *bus)
 131{
 132        acpi_handle handle = ACPI_HANDLE(bus->bridge);
 133
 134        if (handle) {
 135                mutex_lock(&slot_list_lock);
 136                acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
 137                                    register_slot, NULL, bus, NULL);
 138                mutex_unlock(&slot_list_lock);
 139        }
 140}
 141
 142void acpi_pci_slot_remove(struct pci_bus *bus)
 143{
 144        struct acpi_pci_slot *slot, *tmp;
 145
 146        mutex_lock(&slot_list_lock);
 147        list_for_each_entry_safe(slot, tmp, &slot_list, list) {
 148                if (slot->pci_slot->bus == bus) {
 149                        list_del(&slot->list);
 150                        pci_destroy_slot(slot->pci_slot);
 151                        put_device(&bus->dev);
 152                        kfree(slot);
 153                }
 154        }
 155        mutex_unlock(&slot_list_lock);
 156}
 157
 158static int do_sta_before_sun(const struct dmi_system_id *d)
 159{
 160        pr_info("%s detected: will evaluate _STA before calling _SUN\n",
 161                d->ident);
 162        check_sta_before_sun = 1;
 163        return 0;
 164}
 165
 166static const struct dmi_system_id acpi_pci_slot_dmi_table[] __initconst = {
 167        /*
 168         * Fujitsu Primequest machines will return 1023 to indicate an
 169         * error if the _SUN method is evaluated on SxFy objects that
 170         * are not present (as indicated by _STA), so for those machines,
 171         * we want to check _STA before evaluating _SUN.
 172         */
 173        {
 174         .callback = do_sta_before_sun,
 175         .ident = "Fujitsu PRIMEQUEST",
 176         .matches = {
 177                DMI_MATCH(DMI_BIOS_VENDOR, "FUJITSU LIMITED"),
 178                DMI_MATCH(DMI_BIOS_VERSION, "PRIMEQUEST"),
 179                },
 180        },
 181        {}
 182};
 183
 184void __init acpi_pci_slot_init(void)
 185{
 186        dmi_check_system(acpi_pci_slot_dmi_table);
 187}
 188