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