xref: /openbmc/linux/arch/arm64/kernel/pci.c (revision b9d60124)
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  */
pcibios_alloc_irq(struct pci_dev * dev)23 int 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  */
raw_pci_read(unsigned int domain,unsigned int bus,unsigned int devfn,int reg,int len,u32 * val)35 int 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, bus);
39 
40 	if (!b)
41 		return PCIBIOS_DEVICE_NOT_FOUND;
42 	return b->ops->read(b, devfn, reg, len, val);
43 }
44 
raw_pci_write(unsigned int domain,unsigned int bus,unsigned int devfn,int reg,int len,u32 val)45 int 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, 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 
pcibus_to_node(struct pci_bus * bus)57 int pcibus_to_node(struct pci_bus *bus)
58 {
59 	return dev_to_node(&bus->dev);
60 }
61 EXPORT_SYMBOL(pcibus_to_node);
62 
63 #endif
64 
65 #ifdef CONFIG_ACPI
66 
67 struct acpi_pci_generic_root_info {
68 	struct acpi_pci_root_info	common;
69 	struct pci_config_window	*cfg;	/* config space mapping */
70 };
71 
acpi_pci_bus_find_domain_nr(struct pci_bus * bus)72 int 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(adev);
77 
78 	return root->segment;
79 }
80 
pcibios_root_bridge_prepare(struct pci_host_bridge * bridge)81 int 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(bus_dev, acpi_get_node(acpi_device_handle(adev)));
106 
107 	return 0;
108 }
109 
pci_acpi_root_prepare_resources(struct acpi_pci_root_info * ci)110 static 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(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  */
127 static struct pci_config_window *
pci_acpi_setup_ecam_mapping(struct acpi_pci_root * root)128 pci_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, &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(&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, bus_res, ecam_ops);
154 	if (IS_ERR(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 */
pci_acpi_generic_release_info(struct acpi_pci_root_info * ci)164 static 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(ri->cfg);
170 	kfree(ci->ops);
171 	kfree(ri);
172 }
173 
174 /* Interface called from ACPI code to setup PCI host controller */
pci_acpi_scan_root(struct acpi_pci_root * root)175 struct 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(sizeof(*ri), GFP_KERNEL);
183 	if (!ri)
184 		return NULL;
185 
186 	root_ops = kzalloc(sizeof(*root_ops), GFP_KERNEL);
187 	if (!root_ops) {
188 		kfree(ri);
189 		return NULL;
190 	}
191 
192 	ri->cfg = pci_acpi_setup_ecam_mapping(root);
193 	if (!ri->cfg) {
194 		kfree(ri);
195 		kfree(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, root_ops, &ri->common, 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(child);
219 
220 	return bus;
221 }
222 
pcibios_add_bus(struct pci_bus * bus)223 void pcibios_add_bus(struct pci_bus *bus)
224 {
225 	acpi_pci_add_bus(bus);
226 }
227 
pcibios_remove_bus(struct pci_bus * bus)228 void pcibios_remove_bus(struct pci_bus *bus)
229 {
230 	acpi_pci_remove_bus(bus);
231 }
232 
233 #endif
234