1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Support routines for initializing a PCI subsystem
4 *
5 * Extruded from code written by
6 * Dave Rusling (david.rusling@reo.mts.dec.com)
7 * David Mosberger (davidm@cs.arizona.edu)
8 * David Miller (davem@redhat.com)
9 *
10 * Fixed for multiple PCI buses, 1999 Andrea Arcangeli <andrea@suse.de>
11 *
12 * Nov 2000, Ivan Kokshaysky <ink@jurassic.park.msu.ru>
13 * Resource sorting
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/export.h>
18 #include <linux/pci.h>
19 #include <linux/errno.h>
20 #include <linux/ioport.h>
21 #include <linux/cache.h>
22 #include <linux/slab.h>
23 #include "pci.h"
24
pci_std_update_resource(struct pci_dev * dev,int resno)25 static void pci_std_update_resource(struct pci_dev *dev, int resno)
26 {
27 struct pci_bus_region region;
28 bool disable;
29 u16 cmd;
30 u32 new, check, mask;
31 int reg;
32 struct resource *res = dev->resource + resno;
33
34 /* Per SR-IOV spec 3.4.1.11, VF BARs are RO zero */
35 if (dev->is_virtfn)
36 return;
37
38 /*
39 * Ignore resources for unimplemented BARs and unused resource slots
40 * for 64 bit BARs.
41 */
42 if (!res->flags)
43 return;
44
45 if (res->flags & IORESOURCE_UNSET)
46 return;
47
48 /*
49 * Ignore non-moveable resources. This might be legacy resources for
50 * which no functional BAR register exists or another important
51 * system resource we shouldn't move around.
52 */
53 if (res->flags & IORESOURCE_PCI_FIXED)
54 return;
55
56 pcibios_resource_to_bus(dev->bus, ®ion, res);
57 new = region.start;
58
59 if (res->flags & IORESOURCE_IO) {
60 mask = (u32)PCI_BASE_ADDRESS_IO_MASK;
61 new |= res->flags & ~PCI_BASE_ADDRESS_IO_MASK;
62 } else if (resno == PCI_ROM_RESOURCE) {
63 mask = PCI_ROM_ADDRESS_MASK;
64 } else {
65 mask = (u32)PCI_BASE_ADDRESS_MEM_MASK;
66 new |= res->flags & ~PCI_BASE_ADDRESS_MEM_MASK;
67 }
68
69 if (resno < PCI_ROM_RESOURCE) {
70 reg = PCI_BASE_ADDRESS_0 + 4 * resno;
71 } else if (resno == PCI_ROM_RESOURCE) {
72
73 /*
74 * Apparently some Matrox devices have ROM BARs that read
75 * as zero when disabled, so don't update ROM BARs unless
76 * they're enabled. See
77 * https://lore.kernel.org/r/43147B3D.1030309@vc.cvut.cz/
78 * But we must update ROM BAR for buggy devices where even a
79 * disabled ROM can conflict with other BARs.
80 */
81 if (!(res->flags & IORESOURCE_ROM_ENABLE) &&
82 !dev->rom_bar_overlap)
83 return;
84
85 reg = dev->rom_base_reg;
86 if (res->flags & IORESOURCE_ROM_ENABLE)
87 new |= PCI_ROM_ADDRESS_ENABLE;
88 } else
89 return;
90
91 /*
92 * We can't update a 64-bit BAR atomically, so when possible,
93 * disable decoding so that a half-updated BAR won't conflict
94 * with another device.
95 */
96 disable = (res->flags & IORESOURCE_MEM_64) && !dev->mmio_always_on;
97 if (disable) {
98 pci_read_config_word(dev, PCI_COMMAND, &cmd);
99 pci_write_config_word(dev, PCI_COMMAND,
100 cmd & ~PCI_COMMAND_MEMORY);
101 }
102
103 pci_write_config_dword(dev, reg, new);
104 pci_read_config_dword(dev, reg, &check);
105
106 if ((new ^ check) & mask) {
107 pci_err(dev, "BAR %d: error updating (%#08x != %#08x)\n",
108 resno, new, check);
109 }
110
111 if (res->flags & IORESOURCE_MEM_64) {
112 new = region.start >> 16 >> 16;
113 pci_write_config_dword(dev, reg + 4, new);
114 pci_read_config_dword(dev, reg + 4, &check);
115 if (check != new) {
116 pci_err(dev, "BAR %d: error updating (high %#08x != %#08x)\n",
117 resno, new, check);
118 }
119 }
120
121 if (disable)
122 pci_write_config_word(dev, PCI_COMMAND, cmd);
123 }
124
pci_update_resource(struct pci_dev * dev,int resno)125 void pci_update_resource(struct pci_dev *dev, int resno)
126 {
127 if (resno <= PCI_ROM_RESOURCE)
128 pci_std_update_resource(dev, resno);
129 #ifdef CONFIG_PCI_IOV
130 else if (resno >= PCI_IOV_RESOURCES && resno <= PCI_IOV_RESOURCE_END)
131 pci_iov_update_resource(dev, resno);
132 #endif
133 }
134
pci_claim_resource(struct pci_dev * dev,int resource)135 int pci_claim_resource(struct pci_dev *dev, int resource)
136 {
137 struct resource *res = &dev->resource[resource];
138 struct resource *root, *conflict;
139
140 if (res->flags & IORESOURCE_UNSET) {
141 pci_info(dev, "can't claim BAR %d %pR: no address assigned\n",
142 resource, res);
143 return -EINVAL;
144 }
145
146 /*
147 * If we have a shadow copy in RAM, the PCI device doesn't respond
148 * to the shadow range, so we don't need to claim it, and upstream
149 * bridges don't need to route the range to the device.
150 */
151 if (res->flags & IORESOURCE_ROM_SHADOW)
152 return 0;
153
154 root = pci_find_parent_resource(dev, res);
155 if (!root) {
156 pci_info(dev, "can't claim BAR %d %pR: no compatible bridge window\n",
157 resource, res);
158 res->flags |= IORESOURCE_UNSET;
159 return -EINVAL;
160 }
161
162 conflict = request_resource_conflict(root, res);
163 if (conflict) {
164 pci_info(dev, "can't claim BAR %d %pR: address conflict with %s %pR\n",
165 resource, res, conflict->name, conflict);
166 res->flags |= IORESOURCE_UNSET;
167 return -EBUSY;
168 }
169
170 return 0;
171 }
172 EXPORT_SYMBOL(pci_claim_resource);
173
pci_disable_bridge_window(struct pci_dev * dev)174 void pci_disable_bridge_window(struct pci_dev *dev)
175 {
176 /* MMIO Base/Limit */
177 pci_write_config_dword(dev, PCI_MEMORY_BASE, 0x0000fff0);
178
179 /* Prefetchable MMIO Base/Limit */
180 pci_write_config_dword(dev, PCI_PREF_LIMIT_UPPER32, 0);
181 pci_write_config_dword(dev, PCI_PREF_MEMORY_BASE, 0x0000fff0);
182 pci_write_config_dword(dev, PCI_PREF_BASE_UPPER32, 0xffffffff);
183 }
184
185 /*
186 * Generic function that returns a value indicating that the device's
187 * original BIOS BAR address was not saved and so is not available for
188 * reinstatement.
189 *
190 * Can be over-ridden by architecture specific code that implements
191 * reinstatement functionality rather than leaving it disabled when
192 * normal allocation attempts fail.
193 */
pcibios_retrieve_fw_addr(struct pci_dev * dev,int idx)194 resource_size_t __weak pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx)
195 {
196 return 0;
197 }
198
pci_revert_fw_address(struct resource * res,struct pci_dev * dev,int resno,resource_size_t size)199 static int pci_revert_fw_address(struct resource *res, struct pci_dev *dev,
200 int resno, resource_size_t size)
201 {
202 struct resource *root, *conflict;
203 resource_size_t fw_addr, start, end;
204
205 fw_addr = pcibios_retrieve_fw_addr(dev, resno);
206 if (!fw_addr)
207 return -ENOMEM;
208
209 start = res->start;
210 end = res->end;
211 res->start = fw_addr;
212 res->end = res->start + size - 1;
213 res->flags &= ~IORESOURCE_UNSET;
214
215 root = pci_find_parent_resource(dev, res);
216 if (!root) {
217 /*
218 * If dev is behind a bridge, accesses will only reach it
219 * if res is inside the relevant bridge window.
220 */
221 if (pci_upstream_bridge(dev))
222 return -ENXIO;
223
224 /*
225 * On the root bus, assume the host bridge will forward
226 * everything.
227 */
228 if (res->flags & IORESOURCE_IO)
229 root = &ioport_resource;
230 else
231 root = &iomem_resource;
232 }
233
234 pci_info(dev, "BAR %d: trying firmware assignment %pR\n",
235 resno, res);
236 conflict = request_resource_conflict(root, res);
237 if (conflict) {
238 pci_info(dev, "BAR %d: %pR conflicts with %s %pR\n",
239 resno, res, conflict->name, conflict);
240 res->start = start;
241 res->end = end;
242 res->flags |= IORESOURCE_UNSET;
243 return -EBUSY;
244 }
245 return 0;
246 }
247
248 /*
249 * We don't have to worry about legacy ISA devices, so nothing to do here.
250 * This is marked as __weak because multiple architectures define it; it should
251 * eventually go away.
252 */
pcibios_align_resource(void * data,const struct resource * res,resource_size_t size,resource_size_t align)253 resource_size_t __weak pcibios_align_resource(void *data,
254 const struct resource *res,
255 resource_size_t size,
256 resource_size_t align)
257 {
258 return res->start;
259 }
260
__pci_assign_resource(struct pci_bus * bus,struct pci_dev * dev,int resno,resource_size_t size,resource_size_t align)261 static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
262 int resno, resource_size_t size, resource_size_t align)
263 {
264 struct resource *res = dev->resource + resno;
265 resource_size_t min;
266 int ret;
267
268 min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
269
270 /*
271 * First, try exact prefetching match. Even if a 64-bit
272 * prefetchable bridge window is below 4GB, we can't put a 32-bit
273 * prefetchable resource in it because pbus_size_mem() assumes a
274 * 64-bit window will contain no 32-bit resources. If we assign
275 * things differently than they were sized, not everything will fit.
276 */
277 ret = pci_bus_alloc_resource(bus, res, size, align, min,
278 IORESOURCE_PREFETCH | IORESOURCE_MEM_64,
279 pcibios_align_resource, dev);
280 if (ret == 0)
281 return 0;
282
283 /*
284 * If the prefetchable window is only 32 bits wide, we can put
285 * 64-bit prefetchable resources in it.
286 */
287 if ((res->flags & (IORESOURCE_PREFETCH | IORESOURCE_MEM_64)) ==
288 (IORESOURCE_PREFETCH | IORESOURCE_MEM_64)) {
289 ret = pci_bus_alloc_resource(bus, res, size, align, min,
290 IORESOURCE_PREFETCH,
291 pcibios_align_resource, dev);
292 if (ret == 0)
293 return 0;
294 }
295
296 /*
297 * If we didn't find a better match, we can put any memory resource
298 * in a non-prefetchable window. If this resource is 32 bits and
299 * non-prefetchable, the first call already tried the only possibility
300 * so we don't need to try again.
301 */
302 if (res->flags & (IORESOURCE_PREFETCH | IORESOURCE_MEM_64))
303 ret = pci_bus_alloc_resource(bus, res, size, align, min, 0,
304 pcibios_align_resource, dev);
305
306 return ret;
307 }
308
_pci_assign_resource(struct pci_dev * dev,int resno,resource_size_t size,resource_size_t min_align)309 static int _pci_assign_resource(struct pci_dev *dev, int resno,
310 resource_size_t size, resource_size_t min_align)
311 {
312 struct pci_bus *bus;
313 int ret;
314
315 bus = dev->bus;
316 while ((ret = __pci_assign_resource(bus, dev, resno, size, min_align))) {
317 if (!bus->parent || !bus->self->transparent)
318 break;
319 bus = bus->parent;
320 }
321
322 return ret;
323 }
324
pci_assign_resource(struct pci_dev * dev,int resno)325 int pci_assign_resource(struct pci_dev *dev, int resno)
326 {
327 struct resource *res = dev->resource + resno;
328 resource_size_t align, size;
329 int ret;
330
331 if (res->flags & IORESOURCE_PCI_FIXED)
332 return 0;
333
334 res->flags |= IORESOURCE_UNSET;
335 align = pci_resource_alignment(dev, res);
336 if (!align) {
337 pci_info(dev, "BAR %d: can't assign %pR (bogus alignment)\n",
338 resno, res);
339 return -EINVAL;
340 }
341
342 size = resource_size(res);
343 ret = _pci_assign_resource(dev, resno, size, align);
344
345 /*
346 * If we failed to assign anything, let's try the address
347 * where firmware left it. That at least has a chance of
348 * working, which is better than just leaving it disabled.
349 */
350 if (ret < 0) {
351 pci_info(dev, "BAR %d: no space for %pR\n", resno, res);
352 ret = pci_revert_fw_address(res, dev, resno, size);
353 }
354
355 if (ret < 0) {
356 pci_info(dev, "BAR %d: failed to assign %pR\n", resno, res);
357 return ret;
358 }
359
360 res->flags &= ~IORESOURCE_UNSET;
361 res->flags &= ~IORESOURCE_STARTALIGN;
362 pci_info(dev, "BAR %d: assigned %pR\n", resno, res);
363 if (resno < PCI_BRIDGE_RESOURCES)
364 pci_update_resource(dev, resno);
365
366 return 0;
367 }
368 EXPORT_SYMBOL(pci_assign_resource);
369
pci_reassign_resource(struct pci_dev * dev,int resno,resource_size_t addsize,resource_size_t min_align)370 int pci_reassign_resource(struct pci_dev *dev, int resno, resource_size_t addsize,
371 resource_size_t min_align)
372 {
373 struct resource *res = dev->resource + resno;
374 unsigned long flags;
375 resource_size_t new_size;
376 int ret;
377
378 if (res->flags & IORESOURCE_PCI_FIXED)
379 return 0;
380
381 flags = res->flags;
382 res->flags |= IORESOURCE_UNSET;
383 if (!res->parent) {
384 pci_info(dev, "BAR %d: can't reassign an unassigned resource %pR\n",
385 resno, res);
386 return -EINVAL;
387 }
388
389 /* already aligned with min_align */
390 new_size = resource_size(res) + addsize;
391 ret = _pci_assign_resource(dev, resno, new_size, min_align);
392 if (ret) {
393 res->flags = flags;
394 pci_info(dev, "BAR %d: %pR (failed to expand by %#llx)\n",
395 resno, res, (unsigned long long) addsize);
396 return ret;
397 }
398
399 res->flags &= ~IORESOURCE_UNSET;
400 res->flags &= ~IORESOURCE_STARTALIGN;
401 pci_info(dev, "BAR %d: reassigned %pR (expanded by %#llx)\n",
402 resno, res, (unsigned long long) addsize);
403 if (resno < PCI_BRIDGE_RESOURCES)
404 pci_update_resource(dev, resno);
405
406 return 0;
407 }
408
pci_release_resource(struct pci_dev * dev,int resno)409 void pci_release_resource(struct pci_dev *dev, int resno)
410 {
411 struct resource *res = dev->resource + resno;
412
413 pci_info(dev, "BAR %d: releasing %pR\n", resno, res);
414
415 if (!res->parent)
416 return;
417
418 release_resource(res);
419 res->end = resource_size(res) - 1;
420 res->start = 0;
421 res->flags |= IORESOURCE_UNSET;
422 }
423 EXPORT_SYMBOL(pci_release_resource);
424
pci_resize_resource(struct pci_dev * dev,int resno,int size)425 int pci_resize_resource(struct pci_dev *dev, int resno, int size)
426 {
427 struct resource *res = dev->resource + resno;
428 struct pci_host_bridge *host;
429 int old, ret;
430 u32 sizes;
431 u16 cmd;
432
433 /* Check if we must preserve the firmware's resource assignment */
434 host = pci_find_host_bridge(dev->bus);
435 if (host->preserve_config)
436 return -ENOTSUPP;
437
438 /* Make sure the resource isn't assigned before resizing it. */
439 if (!(res->flags & IORESOURCE_UNSET))
440 return -EBUSY;
441
442 pci_read_config_word(dev, PCI_COMMAND, &cmd);
443 if (cmd & PCI_COMMAND_MEMORY)
444 return -EBUSY;
445
446 sizes = pci_rebar_get_possible_sizes(dev, resno);
447 if (!sizes)
448 return -ENOTSUPP;
449
450 if (!(sizes & BIT(size)))
451 return -EINVAL;
452
453 old = pci_rebar_get_current_size(dev, resno);
454 if (old < 0)
455 return old;
456
457 ret = pci_rebar_set_size(dev, resno, size);
458 if (ret)
459 return ret;
460
461 res->end = res->start + pci_rebar_size_to_bytes(size) - 1;
462
463 /* Check if the new config works by trying to assign everything. */
464 if (dev->bus->self) {
465 ret = pci_reassign_bridge_resources(dev->bus->self, res->flags);
466 if (ret)
467 goto error_resize;
468 }
469 return 0;
470
471 error_resize:
472 pci_rebar_set_size(dev, resno, old);
473 res->end = res->start + pci_rebar_size_to_bytes(old) - 1;
474 return ret;
475 }
476 EXPORT_SYMBOL(pci_resize_resource);
477
pci_enable_resources(struct pci_dev * dev,int mask)478 int pci_enable_resources(struct pci_dev *dev, int mask)
479 {
480 u16 cmd, old_cmd;
481 int i;
482 struct resource *r;
483
484 pci_read_config_word(dev, PCI_COMMAND, &cmd);
485 old_cmd = cmd;
486
487 for (i = 0; i < PCI_NUM_RESOURCES; i++) {
488 if (!(mask & (1 << i)))
489 continue;
490
491 r = &dev->resource[i];
492
493 if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
494 continue;
495 if ((i == PCI_ROM_RESOURCE) &&
496 (!(r->flags & IORESOURCE_ROM_ENABLE)))
497 continue;
498
499 if (r->flags & IORESOURCE_UNSET) {
500 pci_err(dev, "can't enable device: BAR %d %pR not assigned\n",
501 i, r);
502 return -EINVAL;
503 }
504
505 if (!r->parent) {
506 pci_err(dev, "can't enable device: BAR %d %pR not claimed\n",
507 i, r);
508 return -EINVAL;
509 }
510
511 if (r->flags & IORESOURCE_IO)
512 cmd |= PCI_COMMAND_IO;
513 if (r->flags & IORESOURCE_MEM)
514 cmd |= PCI_COMMAND_MEMORY;
515 }
516
517 if (cmd != old_cmd) {
518 pci_info(dev, "enabling device (%04x -> %04x)\n", old_cmd, cmd);
519 pci_write_config_word(dev, PCI_COMMAND, cmd);
520 }
521 return 0;
522 }
523