drivers/acpi/pci_slot.c

   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
  29 static int check_sta_before_sun;
  30
  31 #define SLOT_NAME_SIZE 21               /* Inspired by #define in acpiphp.h */
  32
  33 struct 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
  38 static LIST_HEAD(slot_list);
  39 static DEFINE_MUTEX(slot_list_lock);
  40
  41 static int
  42 check_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;
  75 out:
  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  */
  83 static acpi_status
  84 register_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
 130 void 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
 142 void 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
 158 static 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
 166 static 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
 184 void __init acpi_pci_slot_init(void)
 185 {
 186         dmi_check_system(acpi_pci_slot_dmi_table);
 187 }