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 %pe\n", 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