1 /*
2 * Simple, generic PCI host controller driver targetting firmware-initialised
3 * systems and virtual machines (e.g. the PCI emulation provided by kvmtool).
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
16 *
17 * Copyright (C) 2014 ARM Limited
18 *
19 * Author: Will Deacon <will.deacon@arm.com>
20 */
21
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/of_address.h>
25 #include <linux/of_pci.h>
26 #include <linux/platform_device.h>
27
28 struct gen_pci_cfg_bus_ops {
29 u32 bus_shift;
30 void __iomem *(*map_bus)(struct pci_bus *, unsigned int, int);
31 };
32
33 struct gen_pci_cfg_windows {
34 struct resource res;
35 struct resource bus_range;
36 void __iomem **win;
37
38 const struct gen_pci_cfg_bus_ops *ops;
39 };
40
41 struct gen_pci {
42 struct pci_host_bridge host;
43 struct gen_pci_cfg_windows cfg;
44 struct list_head resources;
45 };
46
gen_pci_map_cfg_bus_cam(struct pci_bus * bus,unsigned int devfn,int where)47 static void __iomem *gen_pci_map_cfg_bus_cam(struct pci_bus *bus,
48 unsigned int devfn,
49 int where)
50 {
51 struct pci_sys_data *sys = bus->sysdata;
52 struct gen_pci *pci = sys->private_data;
53 resource_size_t idx = bus->number - pci->cfg.bus_range.start;
54
55 return pci->cfg.win[idx] + ((devfn << 8) | where);
56 }
57
58 static struct gen_pci_cfg_bus_ops gen_pci_cfg_cam_bus_ops = {
59 .bus_shift = 16,
60 .map_bus = gen_pci_map_cfg_bus_cam,
61 };
62
gen_pci_map_cfg_bus_ecam(struct pci_bus * bus,unsigned int devfn,int where)63 static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus,
64 unsigned int devfn,
65 int where)
66 {
67 struct pci_sys_data *sys = bus->sysdata;
68 struct gen_pci *pci = sys->private_data;
69 resource_size_t idx = bus->number - pci->cfg.bus_range.start;
70
71 return pci->cfg.win[idx] + ((devfn << 12) | where);
72 }
73
74 static struct gen_pci_cfg_bus_ops gen_pci_cfg_ecam_bus_ops = {
75 .bus_shift = 20,
76 .map_bus = gen_pci_map_cfg_bus_ecam,
77 };
78
gen_pci_config_read(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 * val)79 static int gen_pci_config_read(struct pci_bus *bus, unsigned int devfn,
80 int where, int size, u32 *val)
81 {
82 void __iomem *addr;
83 struct pci_sys_data *sys = bus->sysdata;
84 struct gen_pci *pci = sys->private_data;
85
86 addr = pci->cfg.ops->map_bus(bus, devfn, where);
87
88 switch (size) {
89 case 1:
90 *val = readb(addr);
91 break;
92 case 2:
93 *val = readw(addr);
94 break;
95 default:
96 *val = readl(addr);
97 }
98
99 return PCIBIOS_SUCCESSFUL;
100 }
101
gen_pci_config_write(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 val)102 static int gen_pci_config_write(struct pci_bus *bus, unsigned int devfn,
103 int where, int size, u32 val)
104 {
105 void __iomem *addr;
106 struct pci_sys_data *sys = bus->sysdata;
107 struct gen_pci *pci = sys->private_data;
108
109 addr = pci->cfg.ops->map_bus(bus, devfn, where);
110
111 switch (size) {
112 case 1:
113 writeb(val, addr);
114 break;
115 case 2:
116 writew(val, addr);
117 break;
118 default:
119 writel(val, addr);
120 }
121
122 return PCIBIOS_SUCCESSFUL;
123 }
124
125 static struct pci_ops gen_pci_ops = {
126 .read = gen_pci_config_read,
127 .write = gen_pci_config_write,
128 };
129
130 static const struct of_device_id gen_pci_of_match[] = {
131 { .compatible = "pci-host-cam-generic",
132 .data = &gen_pci_cfg_cam_bus_ops },
133
134 { .compatible = "pci-host-ecam-generic",
135 .data = &gen_pci_cfg_ecam_bus_ops },
136
137 { },
138 };
139 MODULE_DEVICE_TABLE(of, gen_pci_of_match);
140
gen_pci_calc_io_offset(struct device * dev,struct of_pci_range * range,struct resource * res,resource_size_t * offset)141 static int gen_pci_calc_io_offset(struct device *dev,
142 struct of_pci_range *range,
143 struct resource *res,
144 resource_size_t *offset)
145 {
146 static atomic_t wins = ATOMIC_INIT(0);
147 int err, idx, max_win;
148 unsigned int window;
149
150 if (!PAGE_ALIGNED(range->cpu_addr))
151 return -EINVAL;
152
153 max_win = (IO_SPACE_LIMIT + 1) / SZ_64K;
154 idx = atomic_inc_return(&wins);
155 if (idx > max_win)
156 return -ENOSPC;
157
158 window = (idx - 1) * SZ_64K;
159 err = pci_ioremap_io(window, range->cpu_addr);
160 if (err)
161 return err;
162
163 of_pci_range_to_resource(range, dev->of_node, res);
164 res->start = window;
165 res->end = res->start + range->size - 1;
166 *offset = window - range->pci_addr;
167 return 0;
168 }
169
gen_pci_calc_mem_offset(struct device * dev,struct of_pci_range * range,struct resource * res,resource_size_t * offset)170 static int gen_pci_calc_mem_offset(struct device *dev,
171 struct of_pci_range *range,
172 struct resource *res,
173 resource_size_t *offset)
174 {
175 of_pci_range_to_resource(range, dev->of_node, res);
176 *offset = range->cpu_addr - range->pci_addr;
177 return 0;
178 }
179
gen_pci_release_of_pci_ranges(struct gen_pci * pci)180 static void gen_pci_release_of_pci_ranges(struct gen_pci *pci)
181 {
182 struct pci_host_bridge_window *win;
183
184 list_for_each_entry(win, &pci->resources, list)
185 release_resource(win->res);
186
187 pci_free_resource_list(&pci->resources);
188 }
189
gen_pci_parse_request_of_pci_ranges(struct gen_pci * pci)190 static int gen_pci_parse_request_of_pci_ranges(struct gen_pci *pci)
191 {
192 struct of_pci_range range;
193 struct of_pci_range_parser parser;
194 int err, res_valid = 0;
195 struct device *dev = pci->host.dev.parent;
196 struct device_node *np = dev->of_node;
197
198 if (of_pci_range_parser_init(&parser, np)) {
199 dev_err(dev, "missing \"ranges\" property\n");
200 return -EINVAL;
201 }
202
203 for_each_of_pci_range(&parser, &range) {
204 struct resource *parent, *res;
205 resource_size_t offset;
206 u32 restype = range.flags & IORESOURCE_TYPE_BITS;
207
208 res = devm_kmalloc(dev, sizeof(*res), GFP_KERNEL);
209 if (!res) {
210 err = -ENOMEM;
211 goto out_release_res;
212 }
213
214 switch (restype) {
215 case IORESOURCE_IO:
216 parent = &ioport_resource;
217 err = gen_pci_calc_io_offset(dev, &range, res, &offset);
218 break;
219 case IORESOURCE_MEM:
220 parent = &iomem_resource;
221 err = gen_pci_calc_mem_offset(dev, &range, res, &offset);
222 res_valid |= !(res->flags & IORESOURCE_PREFETCH || err);
223 break;
224 default:
225 err = -EINVAL;
226 continue;
227 }
228
229 if (err) {
230 dev_warn(dev,
231 "error %d: failed to add resource [type 0x%x, %lld bytes]\n",
232 err, restype, range.size);
233 continue;
234 }
235
236 err = request_resource(parent, res);
237 if (err)
238 goto out_release_res;
239
240 pci_add_resource_offset(&pci->resources, res, offset);
241 }
242
243 if (!res_valid) {
244 dev_err(dev, "non-prefetchable memory resource required\n");
245 err = -EINVAL;
246 goto out_release_res;
247 }
248
249 return 0;
250
251 out_release_res:
252 gen_pci_release_of_pci_ranges(pci);
253 return err;
254 }
255
gen_pci_parse_map_cfg_windows(struct gen_pci * pci)256 static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
257 {
258 int err;
259 u8 bus_max;
260 resource_size_t busn;
261 struct resource *bus_range;
262 struct device *dev = pci->host.dev.parent;
263 struct device_node *np = dev->of_node;
264
265 if (of_pci_parse_bus_range(np, &pci->cfg.bus_range))
266 pci->cfg.bus_range = (struct resource) {
267 .name = np->name,
268 .start = 0,
269 .end = 0xff,
270 .flags = IORESOURCE_BUS,
271 };
272
273 err = of_address_to_resource(np, 0, &pci->cfg.res);
274 if (err) {
275 dev_err(dev, "missing \"reg\" property\n");
276 return err;
277 }
278
279 pci->cfg.win = devm_kcalloc(dev, resource_size(&pci->cfg.bus_range),
280 sizeof(*pci->cfg.win), GFP_KERNEL);
281 if (!pci->cfg.win)
282 return -ENOMEM;
283
284 /* Limit the bus-range to fit within reg */
285 bus_max = pci->cfg.bus_range.start +
286 (resource_size(&pci->cfg.res) >> pci->cfg.ops->bus_shift) - 1;
287 pci->cfg.bus_range.end = min_t(resource_size_t, pci->cfg.bus_range.end,
288 bus_max);
289
290 /* Map our Configuration Space windows */
291 if (!devm_request_mem_region(dev, pci->cfg.res.start,
292 resource_size(&pci->cfg.res),
293 "Configuration Space"))
294 return -ENOMEM;
295
296 bus_range = &pci->cfg.bus_range;
297 for (busn = bus_range->start; busn <= bus_range->end; ++busn) {
298 u32 idx = busn - bus_range->start;
299 u32 sz = 1 << pci->cfg.ops->bus_shift;
300
301 pci->cfg.win[idx] = devm_ioremap(dev,
302 pci->cfg.res.start + busn * sz,
303 sz);
304 if (!pci->cfg.win[idx])
305 return -ENOMEM;
306 }
307
308 /* Register bus resource */
309 pci_add_resource(&pci->resources, bus_range);
310 return 0;
311 }
312
gen_pci_setup(int nr,struct pci_sys_data * sys)313 static int gen_pci_setup(int nr, struct pci_sys_data *sys)
314 {
315 struct gen_pci *pci = sys->private_data;
316 list_splice_init(&pci->resources, &sys->resources);
317 return 1;
318 }
319
gen_pci_probe(struct platform_device * pdev)320 static int gen_pci_probe(struct platform_device *pdev)
321 {
322 int err;
323 const char *type;
324 const struct of_device_id *of_id;
325 const int *prop;
326 struct device *dev = &pdev->dev;
327 struct device_node *np = dev->of_node;
328 struct gen_pci *pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
329 struct hw_pci hw = {
330 .nr_controllers = 1,
331 .private_data = (void **)&pci,
332 .setup = gen_pci_setup,
333 .map_irq = of_irq_parse_and_map_pci,
334 .ops = &gen_pci_ops,
335 };
336
337 if (!pci)
338 return -ENOMEM;
339
340 type = of_get_property(np, "device_type", NULL);
341 if (!type || strcmp(type, "pci")) {
342 dev_err(dev, "invalid \"device_type\" %s\n", type);
343 return -EINVAL;
344 }
345
346 prop = of_get_property(of_chosen, "linux,pci-probe-only", NULL);
347 if (prop) {
348 if (*prop)
349 pci_add_flags(PCI_PROBE_ONLY);
350 else
351 pci_clear_flags(PCI_PROBE_ONLY);
352 }
353
354 of_id = of_match_node(gen_pci_of_match, np);
355 pci->cfg.ops = of_id->data;
356 pci->host.dev.parent = dev;
357 INIT_LIST_HEAD(&pci->host.windows);
358 INIT_LIST_HEAD(&pci->resources);
359
360 /* Parse our PCI ranges and request their resources */
361 err = gen_pci_parse_request_of_pci_ranges(pci);
362 if (err)
363 return err;
364
365 /* Parse and map our Configuration Space windows */
366 err = gen_pci_parse_map_cfg_windows(pci);
367 if (err) {
368 gen_pci_release_of_pci_ranges(pci);
369 return err;
370 }
371
372 pci_common_init_dev(dev, &hw);
373 return 0;
374 }
375
376 static struct platform_driver gen_pci_driver = {
377 .driver = {
378 .name = "pci-host-generic",
379 .owner = THIS_MODULE,
380 .of_match_table = gen_pci_of_match,
381 },
382 .probe = gen_pci_probe,
383 };
384 module_platform_driver(gen_pci_driver);
385
386 MODULE_DESCRIPTION("Generic PCI host driver");
387 MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
388 MODULE_LICENSE("GPL v2");
389