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, &region, 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