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 _COMPONENT              ACPI_PCI_COMPONENT
  32 ACPI_MODULE_NAME("pci_slot");
  33
  34 #define SLOT_NAME_SIZE 21               /* Inspired by #define in acpiphp.h */
  35
  36 struct acpi_pci_slot {
  37         struct pci_slot *pci_slot;      /* corresponding pci_slot */
  38         struct list_head list;          /* node in the list of slots */
  39 };
  40
  41 static LIST_HEAD(slot_list);
  42 static DEFINE_MUTEX(slot_list_lock);
  43
  44 static int
  45 check_slot(acpi_handle handle, unsigned long long *sun)
  46 {
  47         int device = -1;
  48         unsigned long long adr, sta;
  49         acpi_status status;
  50         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  51
  52         acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
  53         pr_debug("Checking slot on path: %s\n", (char *)buffer.pointer);
  54
  55         if (check_sta_before_sun) {
  56                 /* If SxFy doesn't have _STA, we just assume it's there */
  57                 status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
  58                 if (ACPI_SUCCESS(status) && !(sta & ACPI_STA_DEVICE_PRESENT))
  59                         goto out;
  60         }
  61
  62         status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
  63         if (ACPI_FAILURE(status)) {
  64                 pr_debug("_ADR returned %d on %s\n",
  65                          status, (char *)buffer.pointer);
  66                 goto out;
  67         }
  68
  69         /* No _SUN == not a slot == bail */
  70         status = acpi_evaluate_integer(handle, "_SUN", NULL, sun);
  71         if (ACPI_FAILURE(status)) {
  72                 pr_debug("_SUN returned %d on %s\n",
  73                          status, (char *)buffer.pointer);
  74                 goto out;
  75         }
  76
  77         device = (adr >> 16) & 0xffff;
  78 out:
  79         kfree(buffer.pointer);
  80         return device;
  81 }
  82
  83 /*
  84  * Check whether handle has an associated slot and create PCI slot if it has.
  85  */
  86 static acpi_status
  87 register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
  88 {
  89         int device;
  90         unsigned long long sun;
  91         char name[SLOT_NAME_SIZE];
  92         struct acpi_pci_slot *slot;
  93         struct pci_slot *pci_slot;
  94         struct pci_bus *pci_bus = context;
  95
  96         device = check_slot(handle, &sun);
  97         if (device < 0)
  98                 return AE_OK;
  99
 100         /*
 101          * There may be multiple PCI functions associated with the same slot.
 102          * Check whether PCI slot has already been created for this PCI device.
 103          */
 104         list_for_each_entry(slot, &slot_list, list) {
 105                 pci_slot = slot->pci_slot;
 106                 if (pci_slot->bus == pci_bus && pci_slot->number == device)
 107                         return AE_OK;
 108         }
 109
 110         slot = kmalloc(sizeof(*slot), GFP_KERNEL);
 111         if (!slot)
 112                 return AE_OK;
 113
 114         snprintf(name, sizeof(name), "%llu", sun);
 115         pci_slot = pci_create_slot(pci_bus, device, name, NULL);
 116         if (IS_ERR(pci_slot)) {
 117                 pr_err("pci_create_slot returned %ld\n", PTR_ERR(pci_slot));
 118                 kfree(slot);
 119                 return AE_OK;
 120         }
 121
 122         slot->pci_slot = pci_slot;
 123         list_add(&slot->list, &slot_list);
 124
 125         get_device(&pci_bus->dev);
 126
 127         pr_debug("%p, pci_bus: %x, device: %d, name: %s\n",
 128                  pci_slot, pci_bus->number, device, name);
 129
 130         return AE_OK;
 131 }
 132
 133 void acpi_pci_slot_enumerate(struct pci_bus *bus)
 134 {
 135         acpi_handle handle = ACPI_HANDLE(bus->bridge);
 136
 137         if (handle) {
 138                 mutex_lock(&slot_list_lock);
 139                 acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
 140                                     register_slot, NULL, bus, NULL);
 141                 mutex_unlock(&slot_list_lock);
 142         }
 143 }
 144
 145 void acpi_pci_slot_remove(struct pci_bus *bus)
 146 {
 147         struct acpi_pci_slot *slot, *tmp;
 148
 149         mutex_lock(&slot_list_lock);
 150         list_for_each_entry_safe(slot, tmp, &slot_list, list) {
 151                 if (slot->pci_slot->bus == bus) {
 152                         list_del(&slot->list);
 153                         pci_destroy_slot(slot->pci_slot);
 154                         put_device(&bus->dev);
 155                         kfree(slot);
 156                 }
 157         }
 158         mutex_unlock(&slot_list_lock);
 159 }
 160
 161 static int do_sta_before_sun(const struct dmi_system_id *d)
 162 {
 163         pr_info("%s detected: will evaluate _STA before calling _SUN\n",
 164                 d->ident);
 165         check_sta_before_sun = 1;
 166         return 0;
 167 }
 168
 169 static const struct dmi_system_id acpi_pci_slot_dmi_table[] __initconst = {
 170         /*
 171          * Fujitsu Primequest machines will return 1023 to indicate an
 172          * error if the _SUN method is evaluated on SxFy objects that
 173          * are not present (as indicated by _STA), so for those machines,
 174          * we want to check _STA before evaluating _SUN.
 175          */
 176         {
 177          .callback = do_sta_before_sun,
 178          .ident = "Fujitsu PRIMEQUEST",
 179          .matches = {
 180                 DMI_MATCH(DMI_BIOS_VENDOR, "FUJITSU LIMITED"),
 181                 DMI_MATCH(DMI_BIOS_VERSION, "PRIMEQUEST"),
 182                 },
 183         },
 184         {}
 185 };
 186
 187 void __init acpi_pci_slot_init(void)
 188 {
 189         dmi_check_system(acpi_pci_slot_dmi_table);
 190 }