xref: /openbmc/linux/drivers/acpi/pci_slot.c (revision be690f3e)
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
check_slot(acpi_handle handle,unsigned long long * sun)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
register_slot(acpi_handle handle,u32 lvl,void * context,void ** rv)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 
acpi_pci_slot_enumerate(struct pci_bus * bus)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 
acpi_pci_slot_remove(struct pci_bus * bus)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 
do_sta_before_sun(const struct dmi_system_id * d)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 
acpi_pci_slot_init(void)184 void __init acpi_pci_slot_init(void)
185 {
186 	dmi_check_system(acpi_pci_slot_dmi_table);
187 }
188