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
25static 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 const char *res_name = pci_resource_name(dev, i: resno);
34
35 /* Per SR-IOV spec 3.4.1.11, VF BARs are RO zero */
36 if (dev->is_virtfn)
37 return;
38
39 /*
40 * Ignore resources for unimplemented BARs and unused resource slots
41 * for 64 bit BARs.
42 */
43 if (!res->flags)
44 return;
45
46 if (res->flags & IORESOURCE_UNSET)
47 return;
48
49 /*
50 * Ignore non-moveable resources. This might be legacy resources for
51 * which no functional BAR register exists or another important
52 * system resource we shouldn't move around.
53 */
54 if (res->flags & IORESOURCE_PCI_FIXED)
55 return;
56
57 pcibios_resource_to_bus(bus: dev->bus, region: &region, res);
58 new = region.start;
59
60 if (res->flags & IORESOURCE_IO) {
61 mask = (u32)PCI_BASE_ADDRESS_IO_MASK;
62 new |= res->flags & ~PCI_BASE_ADDRESS_IO_MASK;
63 } else if (resno == PCI_ROM_RESOURCE) {
64 mask = PCI_ROM_ADDRESS_MASK;
65 } else {
66 mask = (u32)PCI_BASE_ADDRESS_MEM_MASK;
67 new |= res->flags & ~PCI_BASE_ADDRESS_MEM_MASK;
68 }
69
70 if (resno < PCI_ROM_RESOURCE) {
71 reg = PCI_BASE_ADDRESS_0 + 4 * resno;
72 } else if (resno == PCI_ROM_RESOURCE) {
73
74 /*
75 * Apparently some Matrox devices have ROM BARs that read
76 * as zero when disabled, so don't update ROM BARs unless
77 * they're enabled. See
78 * https://lore.kernel.org/r/43147B3D.1030309@vc.cvut.cz/
79 * But we must update ROM BAR for buggy devices where even a
80 * disabled ROM can conflict with other BARs.
81 */
82 if (!(res->flags & IORESOURCE_ROM_ENABLE) &&
83 !dev->rom_bar_overlap)
84 return;
85
86 reg = dev->rom_base_reg;
87 if (res->flags & IORESOURCE_ROM_ENABLE)
88 new |= PCI_ROM_ADDRESS_ENABLE;
89 } else
90 return;
91
92 /*
93 * We can't update a 64-bit BAR atomically, so when possible,
94 * disable decoding so that a half-updated BAR won't conflict
95 * with another device.
96 */
97 disable = (res->flags & IORESOURCE_MEM_64) && !dev->mmio_always_on;
98 if (disable) {
99 pci_read_config_word(dev, PCI_COMMAND, val: &cmd);
100 pci_write_config_word(dev, PCI_COMMAND,
101 val: cmd & ~PCI_COMMAND_MEMORY);
102 }
103
104 pci_write_config_dword(dev, where: reg, val: new);
105 pci_read_config_dword(dev, where: reg, val: &check);
106
107 if ((new ^ check) & mask) {
108 pci_err(dev, "%s: error updating (%#010x != %#010x)\n",
109 res_name, new, check);
110 }
111
112 if (res->flags & IORESOURCE_MEM_64) {
113 new = region.start >> 16 >> 16;
114 pci_write_config_dword(dev, where: reg + 4, val: new);
115 pci_read_config_dword(dev, where: reg + 4, val: &check);
116 if (check != new) {
117 pci_err(dev, "%s: error updating (high %#010x != %#010x)\n",
118 res_name, new, check);
119 }
120 }
121
122 if (disable)
123 pci_write_config_word(dev, PCI_COMMAND, val: cmd);
124}
125
126void pci_update_resource(struct pci_dev *dev, int resno)
127{
128 if (resno <= PCI_ROM_RESOURCE)
129 pci_std_update_resource(dev, resno);
130#ifdef CONFIG_PCI_IOV
131 else if (resno >= PCI_IOV_RESOURCES && resno <= PCI_IOV_RESOURCE_END)
132 pci_iov_update_resource(dev, resno);
133#endif
134}
135
136int pci_claim_resource(struct pci_dev *dev, int resource)
137{
138 struct resource *res = &dev->resource[resource];
139 const char *res_name = pci_resource_name(dev, i: resource);
140 struct resource *root, *conflict;
141
142 if (res->flags & IORESOURCE_UNSET) {
143 pci_info(dev, "%s %pR: can't claim; no address assigned\n",
144 res_name, res);
145 return -EINVAL;
146 }
147
148 /*
149 * If we have a shadow copy in RAM, the PCI device doesn't respond
150 * to the shadow range, so we don't need to claim it, and upstream
151 * bridges don't need to route the range to the device.
152 */
153 if (res->flags & IORESOURCE_ROM_SHADOW)
154 return 0;
155
156 root = pci_find_parent_resource(dev, res);
157 if (!root) {
158 pci_info(dev, "%s %pR: can't claim; no compatible bridge window\n",
159 res_name, res);
160 res->flags |= IORESOURCE_UNSET;
161 return -EINVAL;
162 }
163
164 conflict = request_resource_conflict(root, new: res);
165 if (conflict) {
166 pci_info(dev, "%s %pR: can't claim; address conflict with %s %pR\n",
167 res_name, res, conflict->name, conflict);
168 res->flags |= IORESOURCE_UNSET;
169 return -EBUSY;
170 }
171
172 return 0;
173}
174EXPORT_SYMBOL(pci_claim_resource);
175
176void pci_disable_bridge_window(struct pci_dev *dev)
177{
178 /* MMIO Base/Limit */
179 pci_write_config_dword(dev, PCI_MEMORY_BASE, val: 0x0000fff0);
180
181 /* Prefetchable MMIO Base/Limit */
182 pci_write_config_dword(dev, PCI_PREF_LIMIT_UPPER32, val: 0);
183 pci_write_config_dword(dev, PCI_PREF_MEMORY_BASE, val: 0x0000fff0);
184 pci_write_config_dword(dev, PCI_PREF_BASE_UPPER32, val: 0xffffffff);
185}
186
187/*
188 * Generic function that returns a value indicating that the device's
189 * original BIOS BAR address was not saved and so is not available for
190 * reinstatement.
191 *
192 * Can be over-ridden by architecture specific code that implements
193 * reinstatement functionality rather than leaving it disabled when
194 * normal allocation attempts fail.
195 */
196resource_size_t __weak pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx)
197{
198 return 0;
199}
200
201static int pci_revert_fw_address(struct resource *res, struct pci_dev *dev,
202 int resno, resource_size_t size)
203{
204 struct resource *root, *conflict;
205 resource_size_t fw_addr, start, end;
206 const char *res_name = pci_resource_name(dev, i: resno);
207
208 fw_addr = pcibios_retrieve_fw_addr(dev, idx: resno);
209 if (!fw_addr)
210 return -ENOMEM;
211
212 start = res->start;
213 end = res->end;
214 res->start = fw_addr;
215 res->end = res->start + size - 1;
216 res->flags &= ~IORESOURCE_UNSET;
217
218 root = pci_find_parent_resource(dev, res);
219 if (!root) {
220 /*
221 * If dev is behind a bridge, accesses will only reach it
222 * if res is inside the relevant bridge window.
223 */
224 if (pci_upstream_bridge(dev))
225 return -ENXIO;
226
227 /*
228 * On the root bus, assume the host bridge will forward
229 * everything.
230 */
231 if (res->flags & IORESOURCE_IO)
232 root = &ioport_resource;
233 else
234 root = &iomem_resource;
235 }
236
237 pci_info(dev, "%s: trying firmware assignment %pR\n", res_name, res);
238 conflict = request_resource_conflict(root, new: res);
239 if (conflict) {
240 pci_info(dev, "%s %pR: conflicts with %s %pR\n", res_name, res,
241 conflict->name, conflict);
242 res->start = start;
243 res->end = end;
244 res->flags |= IORESOURCE_UNSET;
245 return -EBUSY;
246 }
247 return 0;
248}
249
250/*
251 * We don't have to worry about legacy ISA devices, so nothing to do here.
252 * This is marked as __weak because multiple architectures define it; it should
253 * eventually go away.
254 */
255resource_size_t __weak pcibios_align_resource(void *data,
256 const struct resource *res,
257 resource_size_t size,
258 resource_size_t align)
259{
260 return res->start;
261}
262
263static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
264 int resno, resource_size_t size, resource_size_t align)
265{
266 struct resource *res = dev->resource + resno;
267 resource_size_t min;
268 int ret;
269
270 min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
271
272 /*
273 * First, try exact prefetching match. Even if a 64-bit
274 * prefetchable bridge window is below 4GB, we can't put a 32-bit
275 * prefetchable resource in it because pbus_size_mem() assumes a
276 * 64-bit window will contain no 32-bit resources. If we assign
277 * things differently than they were sized, not everything will fit.
278 */
279 ret = pci_bus_alloc_resource(bus, res, size, align, min,
280 IORESOURCE_PREFETCH | IORESOURCE_MEM_64,
281 alignf: pcibios_align_resource, alignf_data: dev);
282 if (ret == 0)
283 return 0;
284
285 /*
286 * If the prefetchable window is only 32 bits wide, we can put
287 * 64-bit prefetchable resources in it.
288 */
289 if ((res->flags & (IORESOURCE_PREFETCH | IORESOURCE_MEM_64)) ==
290 (IORESOURCE_PREFETCH | IORESOURCE_MEM_64)) {
291 ret = pci_bus_alloc_resource(bus, res, size, align, min,
292 IORESOURCE_PREFETCH,
293 alignf: pcibios_align_resource, alignf_data: dev);
294 if (ret == 0)
295 return 0;
296 }
297
298 /*
299 * If we didn't find a better match, we can put any memory resource
300 * in a non-prefetchable window. If this resource is 32 bits and
301 * non-prefetchable, the first call already tried the only possibility
302 * so we don't need to try again.
303 */
304 if (res->flags & (IORESOURCE_PREFETCH | IORESOURCE_MEM_64))
305 ret = pci_bus_alloc_resource(bus, res, size, align, min, type_mask: 0,
306 alignf: pcibios_align_resource, alignf_data: dev);
307
308 return ret;
309}
310
311static int _pci_assign_resource(struct pci_dev *dev, int resno,
312 resource_size_t size, resource_size_t min_align)
313{
314 struct pci_bus *bus;
315 int ret;
316
317 bus = dev->bus;
318 while ((ret = __pci_assign_resource(bus, dev, resno, size, align: min_align))) {
319 if (!bus->parent || !bus->self->transparent)
320 break;
321 bus = bus->parent;
322 }
323
324 return ret;
325}
326
327int pci_assign_resource(struct pci_dev *dev, int resno)
328{
329 struct resource *res = dev->resource + resno;
330 const char *res_name = pci_resource_name(dev, i: resno);
331 resource_size_t align, size;
332 int ret;
333
334 if (res->flags & IORESOURCE_PCI_FIXED)
335 return 0;
336
337 res->flags |= IORESOURCE_UNSET;
338 align = pci_resource_alignment(dev, res);
339 if (!align) {
340 pci_info(dev, "%s %pR: can't assign; bogus alignment\n",
341 res_name, res);
342 return -EINVAL;
343 }
344
345 size = resource_size(res);
346 ret = _pci_assign_resource(dev, resno, size, min_align: align);
347
348 /*
349 * If we failed to assign anything, let's try the address
350 * where firmware left it. That at least has a chance of
351 * working, which is better than just leaving it disabled.
352 */
353 if (ret < 0) {
354 pci_info(dev, "%s %pR: can't assign; no space\n", res_name, res);
355 ret = pci_revert_fw_address(res, dev, resno, size);
356 }
357
358 if (ret < 0) {
359 pci_info(dev, "%s %pR: failed to assign\n", res_name, res);
360 return ret;
361 }
362
363 res->flags &= ~IORESOURCE_UNSET;
364 res->flags &= ~IORESOURCE_STARTALIGN;
365 pci_info(dev, "%s %pR: assigned\n", res_name, res);
366 if (resno < PCI_BRIDGE_RESOURCES)
367 pci_update_resource(dev, resno);
368
369 return 0;
370}
371EXPORT_SYMBOL(pci_assign_resource);
372
373int pci_reassign_resource(struct pci_dev *dev, int resno,
374 resource_size_t addsize, resource_size_t min_align)
375{
376 struct resource *res = dev->resource + resno;
377 const char *res_name = pci_resource_name(dev, i: resno);
378 unsigned long flags;
379 resource_size_t new_size;
380 int ret;
381
382 if (res->flags & IORESOURCE_PCI_FIXED)
383 return 0;
384
385 flags = res->flags;
386 res->flags |= IORESOURCE_UNSET;
387 if (!res->parent) {
388 pci_info(dev, "%s %pR: can't reassign; unassigned resource\n",
389 res_name, res);
390 return -EINVAL;
391 }
392
393 /* already aligned with min_align */
394 new_size = resource_size(res) + addsize;
395 ret = _pci_assign_resource(dev, resno, size: new_size, min_align);
396 if (ret) {
397 res->flags = flags;
398 pci_info(dev, "%s %pR: failed to expand by %#llx\n",
399 res_name, res, (unsigned long long) addsize);
400 return ret;
401 }
402
403 res->flags &= ~IORESOURCE_UNSET;
404 res->flags &= ~IORESOURCE_STARTALIGN;
405 pci_info(dev, "%s %pR: reassigned; expanded by %#llx\n",
406 res_name, res, (unsigned long long) addsize);
407 if (resno < PCI_BRIDGE_RESOURCES)
408 pci_update_resource(dev, resno);
409
410 return 0;
411}
412
413void pci_release_resource(struct pci_dev *dev, int resno)
414{
415 struct resource *res = dev->resource + resno;
416 const char *res_name = pci_resource_name(dev, i: resno);
417
418 pci_info(dev, "%s %pR: releasing\n", res_name, res);
419
420 if (!res->parent)
421 return;
422
423 release_resource(new: res);
424 res->end = resource_size(res) - 1;
425 res->start = 0;
426 res->flags |= IORESOURCE_UNSET;
427}
428EXPORT_SYMBOL(pci_release_resource);
429
430int pci_resize_resource(struct pci_dev *dev, int resno, int size)
431{
432 struct resource *res = dev->resource + resno;
433 struct pci_host_bridge *host;
434 int old, ret;
435 u32 sizes;
436 u16 cmd;
437
438 /* Check if we must preserve the firmware's resource assignment */
439 host = pci_find_host_bridge(bus: dev->bus);
440 if (host->preserve_config)
441 return -ENOTSUPP;
442
443 /* Make sure the resource isn't assigned before resizing it. */
444 if (!(res->flags & IORESOURCE_UNSET))
445 return -EBUSY;
446
447 pci_read_config_word(dev, PCI_COMMAND, val: &cmd);
448 if (cmd & PCI_COMMAND_MEMORY)
449 return -EBUSY;
450
451 sizes = pci_rebar_get_possible_sizes(pdev: dev, bar: resno);
452 if (!sizes)
453 return -ENOTSUPP;
454
455 if (!(sizes & BIT(size)))
456 return -EINVAL;
457
458 old = pci_rebar_get_current_size(pdev: dev, bar: resno);
459 if (old < 0)
460 return old;
461
462 ret = pci_rebar_set_size(pdev: dev, bar: resno, size);
463 if (ret)
464 return ret;
465
466 res->end = res->start + pci_rebar_size_to_bytes(size) - 1;
467
468 /* Check if the new config works by trying to assign everything. */
469 if (dev->bus->self) {
470 ret = pci_reassign_bridge_resources(bridge: dev->bus->self, type: res->flags);
471 if (ret)
472 goto error_resize;
473 }
474 return 0;
475
476error_resize:
477 pci_rebar_set_size(pdev: dev, bar: resno, size: old);
478 res->end = res->start + pci_rebar_size_to_bytes(size: old) - 1;
479 return ret;
480}
481EXPORT_SYMBOL(pci_resize_resource);
482
483int pci_enable_resources(struct pci_dev *dev, int mask)
484{
485 u16 cmd, old_cmd;
486 int i;
487 struct resource *r;
488 const char *r_name;
489
490 pci_read_config_word(dev, PCI_COMMAND, val: &cmd);
491 old_cmd = cmd;
492
493 pci_dev_for_each_resource(dev, r, i) {
494 if (!(mask & (1 << i)))
495 continue;
496
497 r_name = pci_resource_name(dev, i);
498
499 if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
500 continue;
501 if ((i == PCI_ROM_RESOURCE) &&
502 (!(r->flags & IORESOURCE_ROM_ENABLE)))
503 continue;
504
505 if (r->flags & IORESOURCE_UNSET) {
506 pci_err(dev, "%s %pR: not assigned; can't enable device\n",
507 r_name, r);
508 return -EINVAL;
509 }
510
511 if (!r->parent) {
512 pci_err(dev, "%s %pR: not claimed; can't enable device\n",
513 r_name, r);
514 return -EINVAL;
515 }
516
517 if (r->flags & IORESOURCE_IO)
518 cmd |= PCI_COMMAND_IO;
519 if (r->flags & IORESOURCE_MEM)
520 cmd |= PCI_COMMAND_MEMORY;
521 }
522
523 if (cmd != old_cmd) {
524 pci_info(dev, "enabling device (%04x -> %04x)\n", old_cmd, cmd);
525 pci_write_config_word(dev, PCI_COMMAND, val: cmd);
526 }
527 return 0;
528}
529

source code of linux/drivers/pci/setup-res.c