1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Code borrowed from powerpc/kernel/pci-common.c
4 *
5 * Copyright (C) 2003 Anton Blanchard <anton@au.ibm.com>, IBM
6 * Copyright (C) 2014 ARM Ltd.
7 */
8
9#include <linux/acpi.h>
10#include <linux/init.h>
11#include <linux/io.h>
12#include <linux/kernel.h>
13#include <linux/mm.h>
14#include <linux/pci.h>
15#include <linux/pci-acpi.h>
16#include <linux/pci-ecam.h>
17#include <linux/slab.h>
18
19#ifdef CONFIG_ACPI
20/*
21 * Try to assign the IRQ number when probing a new device
22 */
23int pcibios_alloc_irq(struct pci_dev *dev)
24{
25 if (!acpi_disabled)
26 acpi_pci_irq_enable(dev);
27
28 return 0;
29}
30#endif
31
32/*
33 * raw_pci_read/write - Platform-specific PCI config space access.
34 */
35int raw_pci_read(unsigned int domain, unsigned int bus,
36 unsigned int devfn, int reg, int len, u32 *val)
37{
38 struct pci_bus *b = pci_find_bus(domain, busnr: bus);
39
40 if (!b)
41 return PCIBIOS_DEVICE_NOT_FOUND;
42 return b->ops->read(b, devfn, reg, len, val);
43}
44
45int raw_pci_write(unsigned int domain, unsigned int bus,
46 unsigned int devfn, int reg, int len, u32 val)
47{
48 struct pci_bus *b = pci_find_bus(domain, busnr: bus);
49
50 if (!b)
51 return PCIBIOS_DEVICE_NOT_FOUND;
52 return b->ops->write(b, devfn, reg, len, val);
53}
54
55#ifdef CONFIG_NUMA
56
57int pcibus_to_node(struct pci_bus *bus)
58{
59 return dev_to_node(dev: &bus->dev);
60}
61EXPORT_SYMBOL(pcibus_to_node);
62
63#endif
64
65#ifdef CONFIG_ACPI
66
67struct acpi_pci_generic_root_info {
68 struct acpi_pci_root_info common;
69 struct pci_config_window *cfg; /* config space mapping */
70};
71
72int acpi_pci_bus_find_domain_nr(struct pci_bus *bus)
73{
74 struct pci_config_window *cfg = bus->sysdata;
75 struct acpi_device *adev = to_acpi_device(cfg->parent);
76 struct acpi_pci_root *root = acpi_driver_data(d: adev);
77
78 return root->segment;
79}
80
81int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
82{
83 struct pci_config_window *cfg;
84 struct acpi_device *adev;
85 struct device *bus_dev;
86
87 if (acpi_disabled)
88 return 0;
89
90 cfg = bridge->bus->sysdata;
91
92 /*
93 * On Hyper-V there is no corresponding ACPI device for a root bridge,
94 * therefore ->parent is set as NULL by the driver. And set 'adev' as
95 * NULL in this case because there is no proper ACPI device.
96 */
97 if (!cfg->parent)
98 adev = NULL;
99 else
100 adev = to_acpi_device(cfg->parent);
101
102 bus_dev = &bridge->bus->dev;
103
104 ACPI_COMPANION_SET(&bridge->dev, adev);
105 set_dev_node(dev: bus_dev, node: acpi_get_node(handle: acpi_device_handle(adev)));
106
107 return 0;
108}
109
110static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci)
111{
112 struct resource_entry *entry, *tmp;
113 int status;
114
115 status = acpi_pci_probe_root_resources(info: ci);
116 resource_list_for_each_entry_safe(entry, tmp, &ci->resources) {
117 if (!(entry->res->flags & IORESOURCE_WINDOW))
118 resource_list_destroy_entry(entry);
119 }
120 return status;
121}
122
123/*
124 * Lookup the bus range for the domain in MCFG, and set up config space
125 * mapping.
126 */
127static struct pci_config_window *
128pci_acpi_setup_ecam_mapping(struct acpi_pci_root *root)
129{
130 struct device *dev = &root->device->dev;
131 struct resource *bus_res = &root->secondary;
132 u16 seg = root->segment;
133 const struct pci_ecam_ops *ecam_ops;
134 struct resource cfgres;
135 struct acpi_device *adev;
136 struct pci_config_window *cfg;
137 int ret;
138
139 ret = pci_mcfg_lookup(root, cfgres: &cfgres, ecam_ops: &ecam_ops);
140 if (ret) {
141 dev_err(dev, "%04x:%pR ECAM region not found\n", seg, bus_res);
142 return NULL;
143 }
144
145 adev = acpi_resource_consumer(res: &cfgres);
146 if (adev)
147 dev_info(dev, "ECAM area %pR reserved by %s\n", &cfgres,
148 dev_name(&adev->dev));
149 else
150 dev_warn(dev, FW_BUG "ECAM area %pR not reserved in ACPI namespace\n",
151 &cfgres);
152
153 cfg = pci_ecam_create(dev, cfgres: &cfgres, busr: bus_res, ops: ecam_ops);
154 if (IS_ERR(ptr: cfg)) {
155 dev_err(dev, "%04x:%pR error %ld mapping ECAM\n", seg, bus_res,
156 PTR_ERR(cfg));
157 return NULL;
158 }
159
160 return cfg;
161}
162
163/* release_info: free resources allocated by init_info */
164static void pci_acpi_generic_release_info(struct acpi_pci_root_info *ci)
165{
166 struct acpi_pci_generic_root_info *ri;
167
168 ri = container_of(ci, struct acpi_pci_generic_root_info, common);
169 pci_ecam_free(cfg: ri->cfg);
170 kfree(objp: ci->ops);
171 kfree(objp: ri);
172}
173
174/* Interface called from ACPI code to setup PCI host controller */
175struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
176{
177 struct acpi_pci_generic_root_info *ri;
178 struct pci_bus *bus, *child;
179 struct acpi_pci_root_ops *root_ops;
180 struct pci_host_bridge *host;
181
182 ri = kzalloc(size: sizeof(*ri), GFP_KERNEL);
183 if (!ri)
184 return NULL;
185
186 root_ops = kzalloc(size: sizeof(*root_ops), GFP_KERNEL);
187 if (!root_ops) {
188 kfree(objp: ri);
189 return NULL;
190 }
191
192 ri->cfg = pci_acpi_setup_ecam_mapping(root);
193 if (!ri->cfg) {
194 kfree(objp: ri);
195 kfree(objp: root_ops);
196 return NULL;
197 }
198
199 root_ops->release_info = pci_acpi_generic_release_info;
200 root_ops->prepare_resources = pci_acpi_root_prepare_resources;
201 root_ops->pci_ops = (struct pci_ops *)&ri->cfg->ops->pci_ops;
202 bus = acpi_pci_root_create(root, ops: root_ops, info: &ri->common, sd: ri->cfg);
203 if (!bus)
204 return NULL;
205
206 /* If we must preserve the resource configuration, claim now */
207 host = pci_find_host_bridge(bus);
208 if (host->preserve_config)
209 pci_bus_claim_resources(bus);
210
211 /*
212 * Assign whatever was left unassigned. If we didn't claim above,
213 * this will reassign everything.
214 */
215 pci_assign_unassigned_root_bus_resources(bus);
216
217 list_for_each_entry(child, &bus->children, node)
218 pcie_bus_configure_settings(bus: child);
219
220 return bus;
221}
222
223void pcibios_add_bus(struct pci_bus *bus)
224{
225 acpi_pci_add_bus(bus);
226}
227
228void pcibios_remove_bus(struct pci_bus *bus)
229{
230 acpi_pci_remove_bus(bus);
231}
232
233#endif
234

source code of linux/arch/arm64/kernel/pci.c