xref: /openbmc/linux/drivers/pci/ecam.c (revision 8fe55ef2)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright 2016 Broadcom
4  */
5 
6 #include <linux/device.h>
7 #include <linux/io.h>
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/pci.h>
11 #include <linux/pci-ecam.h>
12 #include <linux/slab.h>
13 
14 /*
15  * On 64-bit systems, we do a single ioremap for the whole config space
16  * since we have enough virtual address range available.  On 32-bit, we
17  * ioremap the config space for each bus individually.
18  */
19 static const bool per_bus_mapping = !IS_ENABLED(CONFIG_64BIT);
20 
21 /*
22  * Create a PCI config space window
23  *  - reserve mem region
24  *  - alloc struct pci_config_window with space for all mappings
25  *  - ioremap the config space
26  */
pci_ecam_create(struct device * dev,struct resource * cfgres,struct resource * busr,const struct pci_ecam_ops * ops)27 struct pci_config_window *pci_ecam_create(struct device *dev,
28 		struct resource *cfgres, struct resource *busr,
29 		const struct pci_ecam_ops *ops)
30 {
31 	unsigned int bus_shift = ops->bus_shift;
32 	struct pci_config_window *cfg;
33 	unsigned int bus_range, bus_range_max, bsz;
34 	struct resource *conflict;
35 	int err;
36 
37 	if (busr->start > busr->end)
38 		return ERR_PTR(-EINVAL);
39 
40 	cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
41 	if (!cfg)
42 		return ERR_PTR(-ENOMEM);
43 
44 	/* ECAM-compliant platforms need not supply ops->bus_shift */
45 	if (!bus_shift)
46 		bus_shift = PCIE_ECAM_BUS_SHIFT;
47 
48 	cfg->parent = dev;
49 	cfg->ops = ops;
50 	cfg->busr.start = busr->start;
51 	cfg->busr.end = busr->end;
52 	cfg->busr.flags = IORESOURCE_BUS;
53 	cfg->bus_shift = bus_shift;
54 	bus_range = resource_size(&cfg->busr);
55 	bus_range_max = resource_size(cfgres) >> bus_shift;
56 	if (bus_range > bus_range_max) {
57 		bus_range = bus_range_max;
58 		cfg->busr.end = busr->start + bus_range - 1;
59 		dev_warn(dev, "ECAM area %pR can only accommodate %pR (reduced from %pR desired)\n",
60 			 cfgres, &cfg->busr, busr);
61 	}
62 	bsz = 1 << bus_shift;
63 
64 	cfg->res.start = cfgres->start;
65 	cfg->res.end = cfgres->end;
66 	cfg->res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
67 	cfg->res.name = "PCI ECAM";
68 
69 	conflict = request_resource_conflict(&iomem_resource, &cfg->res);
70 	if (conflict) {
71 		err = -EBUSY;
72 		dev_err(dev, "can't claim ECAM area %pR: address conflict with %s %pR\n",
73 			&cfg->res, conflict->name, conflict);
74 		goto err_exit;
75 	}
76 
77 	if (per_bus_mapping) {
78 		cfg->winp = kcalloc(bus_range, sizeof(*cfg->winp), GFP_KERNEL);
79 		if (!cfg->winp)
80 			goto err_exit_malloc;
81 	} else {
82 		cfg->win = pci_remap_cfgspace(cfgres->start, bus_range * bsz);
83 		if (!cfg->win)
84 			goto err_exit_iomap;
85 	}
86 
87 	if (ops->init) {
88 		err = ops->init(cfg);
89 		if (err)
90 			goto err_exit;
91 	}
92 	dev_info(dev, "ECAM at %pR for %pR\n", &cfg->res, &cfg->busr);
93 	return cfg;
94 
95 err_exit_iomap:
96 	dev_err(dev, "ECAM ioremap failed\n");
97 err_exit_malloc:
98 	err = -ENOMEM;
99 err_exit:
100 	pci_ecam_free(cfg);
101 	return ERR_PTR(err);
102 }
103 EXPORT_SYMBOL_GPL(pci_ecam_create);
104 
pci_ecam_free(struct pci_config_window * cfg)105 void pci_ecam_free(struct pci_config_window *cfg)
106 {
107 	int i;
108 
109 	if (per_bus_mapping) {
110 		if (cfg->winp) {
111 			for (i = 0; i < resource_size(&cfg->busr); i++)
112 				if (cfg->winp[i])
113 					iounmap(cfg->winp[i]);
114 			kfree(cfg->winp);
115 		}
116 	} else {
117 		if (cfg->win)
118 			iounmap(cfg->win);
119 	}
120 	if (cfg->res.parent)
121 		release_resource(&cfg->res);
122 	kfree(cfg);
123 }
124 EXPORT_SYMBOL_GPL(pci_ecam_free);
125 
pci_ecam_add_bus(struct pci_bus * bus)126 static int pci_ecam_add_bus(struct pci_bus *bus)
127 {
128 	struct pci_config_window *cfg = bus->sysdata;
129 	unsigned int bsz = 1 << cfg->bus_shift;
130 	unsigned int busn = bus->number;
131 	phys_addr_t start;
132 
133 	if (!per_bus_mapping)
134 		return 0;
135 
136 	if (busn < cfg->busr.start || busn > cfg->busr.end)
137 		return -EINVAL;
138 
139 	busn -= cfg->busr.start;
140 	start = cfg->res.start + busn * bsz;
141 
142 	cfg->winp[busn] = pci_remap_cfgspace(start, bsz);
143 	if (!cfg->winp[busn])
144 		return -ENOMEM;
145 
146 	return 0;
147 }
148 
pci_ecam_remove_bus(struct pci_bus * bus)149 static void pci_ecam_remove_bus(struct pci_bus *bus)
150 {
151 	struct pci_config_window *cfg = bus->sysdata;
152 	unsigned int busn = bus->number;
153 
154 	if (!per_bus_mapping || busn < cfg->busr.start || busn > cfg->busr.end)
155 		return;
156 
157 	busn -= cfg->busr.start;
158 	if (cfg->winp[busn]) {
159 		iounmap(cfg->winp[busn]);
160 		cfg->winp[busn] = NULL;
161 	}
162 }
163 
164 /*
165  * Function to implement the pci_ops ->map_bus method
166  */
pci_ecam_map_bus(struct pci_bus * bus,unsigned int devfn,int where)167 void __iomem *pci_ecam_map_bus(struct pci_bus *bus, unsigned int devfn,
168 			       int where)
169 {
170 	struct pci_config_window *cfg = bus->sysdata;
171 	unsigned int bus_shift = cfg->ops->bus_shift;
172 	unsigned int devfn_shift = cfg->ops->bus_shift - 8;
173 	unsigned int busn = bus->number;
174 	void __iomem *base;
175 	u32 bus_offset, devfn_offset;
176 
177 	if (busn < cfg->busr.start || busn > cfg->busr.end)
178 		return NULL;
179 
180 	busn -= cfg->busr.start;
181 	if (per_bus_mapping) {
182 		base = cfg->winp[busn];
183 		busn = 0;
184 	} else
185 		base = cfg->win;
186 
187 	if (cfg->ops->bus_shift) {
188 		bus_offset = (busn & PCIE_ECAM_BUS_MASK) << bus_shift;
189 		devfn_offset = (devfn & PCIE_ECAM_DEVFN_MASK) << devfn_shift;
190 		where &= PCIE_ECAM_REG_MASK;
191 
192 		return base + (bus_offset | devfn_offset | where);
193 	}
194 
195 	return base + PCIE_ECAM_OFFSET(busn, devfn, where);
196 }
197 EXPORT_SYMBOL_GPL(pci_ecam_map_bus);
198 
199 /* ECAM ops */
200 const struct pci_ecam_ops pci_generic_ecam_ops = {
201 	.pci_ops	= {
202 		.add_bus	= pci_ecam_add_bus,
203 		.remove_bus	= pci_ecam_remove_bus,
204 		.map_bus	= pci_ecam_map_bus,
205 		.read		= pci_generic_config_read,
206 		.write		= pci_generic_config_write,
207 	}
208 };
209 EXPORT_SYMBOL_GPL(pci_generic_ecam_ops);
210 
211 #if defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS)
212 /* ECAM ops for 32-bit access only (non-compliant) */
213 const struct pci_ecam_ops pci_32b_ops = {
214 	.pci_ops	= {
215 		.add_bus	= pci_ecam_add_bus,
216 		.remove_bus	= pci_ecam_remove_bus,
217 		.map_bus	= pci_ecam_map_bus,
218 		.read		= pci_generic_config_read32,
219 		.write		= pci_generic_config_write32,
220 	}
221 };
222 
223 /* ECAM ops for 32-bit read only (non-compliant) */
224 const struct pci_ecam_ops pci_32b_read_ops = {
225 	.pci_ops	= {
226 		.add_bus	= pci_ecam_add_bus,
227 		.remove_bus	= pci_ecam_remove_bus,
228 		.map_bus	= pci_ecam_map_bus,
229 		.read		= pci_generic_config_read32,
230 		.write		= pci_generic_config_write,
231 	}
232 };
233 #endif
234