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(object: handle, ACPI_FULL_PATHNAME, ret_path_ptr: &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, pathname: "_STA", NULL, data: &sta);
55 if (ACPI_SUCCESS(status) && !(sta & ACPI_STA_DEVICE_PRESENT))
56 goto out;
57 }
58
59 status = acpi_evaluate_integer(handle, pathname: "_ADR", NULL, data: &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, pathname: "_SUN", NULL, data: 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(objp: 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: &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(size: sizeof(*slot), GFP_KERNEL);
108 if (!slot)
109 return AE_OK;
110
111 snprintf(buf: name, size: sizeof(name), fmt: "%llu", sun);
112 pci_slot = pci_create_slot(parent: pci_bus, slot_nr: device, name, NULL);
113 if (IS_ERR(ptr: pci_slot)) {
114 pr_err("pci_create_slot returned %ld\n", PTR_ERR(pci_slot));
115 kfree(objp: slot);
116 return AE_OK;
117 }
118
119 slot->pci_slot = pci_slot;
120 list_add(new: &slot->list, head: &slot_list);
121
122 get_device(dev: &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, start_object: handle, max_depth: 1,
137 descending_callback: register_slot, NULL, context: bus, NULL);
138 mutex_unlock(lock: &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(entry: &slot->list);
150 pci_destroy_slot(slot: slot->pci_slot);
151 put_device(dev: &bus->dev);
152 kfree(objp: slot);
153 }
154 }
155 mutex_unlock(lock: &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(list: acpi_pci_slot_dmi_table);
187}
188

source code of linux/drivers/acpi/pci_slot.c