xref: /openbmc/linux/drivers/cxl/acpi.c (revision 17bfcd6a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright(c) 2021 Intel Corporation. All rights reserved. */
3 #include <linux/platform_device.h>
4 #include <linux/module.h>
5 #include <linux/device.h>
6 #include <linux/kernel.h>
7 #include <linux/acpi.h>
8 #include <linux/pci.h>
9 #include <asm/div64.h>
10 #include "cxlpci.h"
11 #include "cxl.h"
12 
13 #define CXL_RCRB_SIZE	SZ_8K
14 
15 struct cxl_cxims_data {
16 	int nr_maps;
17 	u64 xormaps[] __counted_by(nr_maps);
18 };
19 
20 /*
21  * Find a targets entry (n) in the host bridge interleave list.
22  * CXL Specification 3.0 Table 9-22
23  */
24 static int cxl_xor_calc_n(u64 hpa, struct cxl_cxims_data *cximsd, int iw,
25 			  int ig)
26 {
27 	int i = 0, n = 0;
28 	u8 eiw;
29 
30 	/* IW: 2,4,6,8,12,16 begin building 'n' using xormaps */
31 	if (iw != 3) {
32 		for (i = 0; i < cximsd->nr_maps; i++)
33 			n |= (hweight64(hpa & cximsd->xormaps[i]) & 1) << i;
34 	}
35 	/* IW: 3,6,12 add a modulo calculation to 'n' */
36 	if (!is_power_of_2(iw)) {
37 		if (ways_to_eiw(iw, &eiw))
38 			return -1;
39 		hpa &= GENMASK_ULL(51, eiw + ig);
40 		n |= do_div(hpa, 3) << i;
41 	}
42 	return n;
43 }
44 
45 static struct cxl_dport *cxl_hb_xor(struct cxl_root_decoder *cxlrd, int pos)
46 {
47 	struct cxl_cxims_data *cximsd = cxlrd->platform_data;
48 	struct cxl_switch_decoder *cxlsd = &cxlrd->cxlsd;
49 	struct cxl_decoder *cxld = &cxlsd->cxld;
50 	int ig = cxld->interleave_granularity;
51 	int iw = cxld->interleave_ways;
52 	int n = 0;
53 	u64 hpa;
54 
55 	if (dev_WARN_ONCE(&cxld->dev,
56 			  cxld->interleave_ways != cxlsd->nr_targets,
57 			  "misconfigured root decoder\n"))
58 		return NULL;
59 
60 	hpa = cxlrd->res->start + pos * ig;
61 
62 	/* Entry (n) is 0 for no interleave (iw == 1) */
63 	if (iw != 1)
64 		n = cxl_xor_calc_n(hpa, cximsd, iw, ig);
65 
66 	if (n < 0)
67 		return NULL;
68 
69 	return cxlrd->cxlsd.target[n];
70 }
71 
72 struct cxl_cxims_context {
73 	struct device *dev;
74 	struct cxl_root_decoder *cxlrd;
75 };
76 
77 static int cxl_parse_cxims(union acpi_subtable_headers *header, void *arg,
78 			   const unsigned long end)
79 {
80 	struct acpi_cedt_cxims *cxims = (struct acpi_cedt_cxims *)header;
81 	struct cxl_cxims_context *ctx = arg;
82 	struct cxl_root_decoder *cxlrd = ctx->cxlrd;
83 	struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
84 	struct device *dev = ctx->dev;
85 	struct cxl_cxims_data *cximsd;
86 	unsigned int hbig, nr_maps;
87 	int rc;
88 
89 	rc = eig_to_granularity(cxims->hbig, &hbig);
90 	if (rc)
91 		return rc;
92 
93 	/* Does this CXIMS entry apply to the given CXL Window? */
94 	if (hbig != cxld->interleave_granularity)
95 		return 0;
96 
97 	/* IW 1,3 do not use xormaps and skip this parsing entirely */
98 	if (is_power_of_2(cxld->interleave_ways))
99 		/* 2, 4, 8, 16 way */
100 		nr_maps = ilog2(cxld->interleave_ways);
101 	else
102 		/* 6, 12 way */
103 		nr_maps = ilog2(cxld->interleave_ways / 3);
104 
105 	if (cxims->nr_xormaps < nr_maps) {
106 		dev_dbg(dev, "CXIMS nr_xormaps[%d] expected[%d]\n",
107 			cxims->nr_xormaps, nr_maps);
108 		return -ENXIO;
109 	}
110 
111 	cximsd = devm_kzalloc(dev, struct_size(cximsd, xormaps, nr_maps),
112 			      GFP_KERNEL);
113 	if (!cximsd)
114 		return -ENOMEM;
115 	cximsd->nr_maps = nr_maps;
116 	memcpy(cximsd->xormaps, cxims->xormap_list,
117 	       nr_maps * sizeof(*cximsd->xormaps));
118 	cxlrd->platform_data = cximsd;
119 
120 	return 0;
121 }
122 
123 static unsigned long cfmws_to_decoder_flags(int restrictions)
124 {
125 	unsigned long flags = CXL_DECODER_F_ENABLE;
126 
127 	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_TYPE2)
128 		flags |= CXL_DECODER_F_TYPE2;
129 	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_TYPE3)
130 		flags |= CXL_DECODER_F_TYPE3;
131 	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_VOLATILE)
132 		flags |= CXL_DECODER_F_RAM;
133 	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_PMEM)
134 		flags |= CXL_DECODER_F_PMEM;
135 	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_FIXED)
136 		flags |= CXL_DECODER_F_LOCK;
137 
138 	return flags;
139 }
140 
141 static int cxl_acpi_cfmws_verify(struct device *dev,
142 				 struct acpi_cedt_cfmws *cfmws)
143 {
144 	int rc, expected_len;
145 	unsigned int ways;
146 
147 	if (cfmws->interleave_arithmetic != ACPI_CEDT_CFMWS_ARITHMETIC_MODULO &&
148 	    cfmws->interleave_arithmetic != ACPI_CEDT_CFMWS_ARITHMETIC_XOR) {
149 		dev_err(dev, "CFMWS Unknown Interleave Arithmetic: %d\n",
150 			cfmws->interleave_arithmetic);
151 		return -EINVAL;
152 	}
153 
154 	if (!IS_ALIGNED(cfmws->base_hpa, SZ_256M)) {
155 		dev_err(dev, "CFMWS Base HPA not 256MB aligned\n");
156 		return -EINVAL;
157 	}
158 
159 	if (!IS_ALIGNED(cfmws->window_size, SZ_256M)) {
160 		dev_err(dev, "CFMWS Window Size not 256MB aligned\n");
161 		return -EINVAL;
162 	}
163 
164 	rc = eiw_to_ways(cfmws->interleave_ways, &ways);
165 	if (rc) {
166 		dev_err(dev, "CFMWS Interleave Ways (%d) invalid\n",
167 			cfmws->interleave_ways);
168 		return -EINVAL;
169 	}
170 
171 	expected_len = struct_size(cfmws, interleave_targets, ways);
172 
173 	if (cfmws->header.length < expected_len) {
174 		dev_err(dev, "CFMWS length %d less than expected %d\n",
175 			cfmws->header.length, expected_len);
176 		return -EINVAL;
177 	}
178 
179 	if (cfmws->header.length > expected_len)
180 		dev_dbg(dev, "CFMWS length %d greater than expected %d\n",
181 			cfmws->header.length, expected_len);
182 
183 	return 0;
184 }
185 
186 /*
187  * Note, @dev must be the first member, see 'struct cxl_chbs_context'
188  * and mock_acpi_table_parse_cedt()
189  */
190 struct cxl_cfmws_context {
191 	struct device *dev;
192 	struct cxl_port *root_port;
193 	struct resource *cxl_res;
194 	int id;
195 };
196 
197 static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg,
198 			   const unsigned long end)
199 {
200 	int target_map[CXL_DECODER_MAX_INTERLEAVE];
201 	struct cxl_cfmws_context *ctx = arg;
202 	struct cxl_port *root_port = ctx->root_port;
203 	struct resource *cxl_res = ctx->cxl_res;
204 	struct cxl_cxims_context cxims_ctx;
205 	struct cxl_root_decoder *cxlrd;
206 	struct device *dev = ctx->dev;
207 	struct acpi_cedt_cfmws *cfmws;
208 	cxl_calc_hb_fn cxl_calc_hb;
209 	struct cxl_decoder *cxld;
210 	unsigned int ways, i, ig;
211 	struct resource *res;
212 	int rc;
213 
214 	cfmws = (struct acpi_cedt_cfmws *) header;
215 
216 	rc = cxl_acpi_cfmws_verify(dev, cfmws);
217 	if (rc) {
218 		dev_err(dev, "CFMWS range %#llx-%#llx not registered\n",
219 			cfmws->base_hpa,
220 			cfmws->base_hpa + cfmws->window_size - 1);
221 		return 0;
222 	}
223 
224 	rc = eiw_to_ways(cfmws->interleave_ways, &ways);
225 	if (rc)
226 		return rc;
227 	rc = eig_to_granularity(cfmws->granularity, &ig);
228 	if (rc)
229 		return rc;
230 	for (i = 0; i < ways; i++)
231 		target_map[i] = cfmws->interleave_targets[i];
232 
233 	res = kzalloc(sizeof(*res), GFP_KERNEL);
234 	if (!res)
235 		return -ENOMEM;
236 
237 	res->name = kasprintf(GFP_KERNEL, "CXL Window %d", ctx->id++);
238 	if (!res->name)
239 		goto err_name;
240 
241 	res->start = cfmws->base_hpa;
242 	res->end = cfmws->base_hpa + cfmws->window_size - 1;
243 	res->flags = IORESOURCE_MEM;
244 
245 	/* add to the local resource tracking to establish a sort order */
246 	rc = insert_resource(cxl_res, res);
247 	if (rc)
248 		goto err_insert;
249 
250 	if (cfmws->interleave_arithmetic == ACPI_CEDT_CFMWS_ARITHMETIC_MODULO)
251 		cxl_calc_hb = cxl_hb_modulo;
252 	else
253 		cxl_calc_hb = cxl_hb_xor;
254 
255 	cxlrd = cxl_root_decoder_alloc(root_port, ways, cxl_calc_hb);
256 	if (IS_ERR(cxlrd))
257 		return 0;
258 
259 	cxld = &cxlrd->cxlsd.cxld;
260 	cxld->flags = cfmws_to_decoder_flags(cfmws->restrictions);
261 	cxld->target_type = CXL_DECODER_HOSTONLYMEM;
262 	cxld->hpa_range = (struct range) {
263 		.start = res->start,
264 		.end = res->end,
265 	};
266 	cxld->interleave_ways = ways;
267 	/*
268 	 * Minimize the x1 granularity to advertise support for any
269 	 * valid region granularity
270 	 */
271 	if (ways == 1)
272 		ig = CXL_DECODER_MIN_GRANULARITY;
273 	cxld->interleave_granularity = ig;
274 
275 	if (cfmws->interleave_arithmetic == ACPI_CEDT_CFMWS_ARITHMETIC_XOR) {
276 		if (ways != 1 && ways != 3) {
277 			cxims_ctx = (struct cxl_cxims_context) {
278 				.dev = dev,
279 				.cxlrd = cxlrd,
280 			};
281 			rc = acpi_table_parse_cedt(ACPI_CEDT_TYPE_CXIMS,
282 						   cxl_parse_cxims, &cxims_ctx);
283 			if (rc < 0)
284 				goto err_xormap;
285 			if (!cxlrd->platform_data) {
286 				dev_err(dev, "No CXIMS for HBIG %u\n", ig);
287 				rc = -EINVAL;
288 				goto err_xormap;
289 			}
290 		}
291 	}
292 	rc = cxl_decoder_add(cxld, target_map);
293 err_xormap:
294 	if (rc)
295 		put_device(&cxld->dev);
296 	else
297 		rc = cxl_decoder_autoremove(dev, cxld);
298 	if (rc) {
299 		dev_err(dev, "Failed to add decode range: %pr", res);
300 		return rc;
301 	}
302 	dev_dbg(dev, "add: %s node: %d range [%#llx - %#llx]\n",
303 		dev_name(&cxld->dev),
304 		phys_to_target_node(cxld->hpa_range.start),
305 		cxld->hpa_range.start, cxld->hpa_range.end);
306 
307 	return 0;
308 
309 err_insert:
310 	kfree(res->name);
311 err_name:
312 	kfree(res);
313 	return -ENOMEM;
314 }
315 
316 __mock struct acpi_device *to_cxl_host_bridge(struct device *host,
317 					      struct device *dev)
318 {
319 	struct acpi_device *adev = to_acpi_device(dev);
320 
321 	if (!acpi_pci_find_root(adev->handle))
322 		return NULL;
323 
324 	if (strcmp(acpi_device_hid(adev), "ACPI0016") == 0)
325 		return adev;
326 	return NULL;
327 }
328 
329 /* Note, @dev is used by mock_acpi_table_parse_cedt() */
330 struct cxl_chbs_context {
331 	struct device *dev;
332 	unsigned long long uid;
333 	resource_size_t base;
334 	u32 cxl_version;
335 };
336 
337 static int cxl_get_chbs_iter(union acpi_subtable_headers *header, void *arg,
338 			     const unsigned long end)
339 {
340 	struct cxl_chbs_context *ctx = arg;
341 	struct acpi_cedt_chbs *chbs;
342 
343 	if (ctx->base != CXL_RESOURCE_NONE)
344 		return 0;
345 
346 	chbs = (struct acpi_cedt_chbs *) header;
347 
348 	if (ctx->uid != chbs->uid)
349 		return 0;
350 
351 	ctx->cxl_version = chbs->cxl_version;
352 	if (!chbs->base)
353 		return 0;
354 
355 	if (chbs->cxl_version == ACPI_CEDT_CHBS_VERSION_CXL11 &&
356 	    chbs->length != CXL_RCRB_SIZE)
357 		return 0;
358 
359 	ctx->base = chbs->base;
360 
361 	return 0;
362 }
363 
364 static int cxl_get_chbs(struct device *dev, struct acpi_device *hb,
365 			struct cxl_chbs_context *ctx)
366 {
367 	unsigned long long uid;
368 	int rc;
369 
370 	rc = acpi_evaluate_integer(hb->handle, METHOD_NAME__UID, NULL, &uid);
371 	if (rc != AE_OK) {
372 		dev_err(dev, "unable to retrieve _UID\n");
373 		return -ENOENT;
374 	}
375 
376 	dev_dbg(dev, "UID found: %lld\n", uid);
377 	*ctx = (struct cxl_chbs_context) {
378 		.dev = dev,
379 		.uid = uid,
380 		.base = CXL_RESOURCE_NONE,
381 		.cxl_version = UINT_MAX,
382 	};
383 
384 	acpi_table_parse_cedt(ACPI_CEDT_TYPE_CHBS, cxl_get_chbs_iter, ctx);
385 
386 	return 0;
387 }
388 
389 static int add_host_bridge_dport(struct device *match, void *arg)
390 {
391 	acpi_status rc;
392 	struct device *bridge;
393 	struct cxl_dport *dport;
394 	struct cxl_chbs_context ctx;
395 	struct acpi_pci_root *pci_root;
396 	struct cxl_port *root_port = arg;
397 	struct device *host = root_port->dev.parent;
398 	struct acpi_device *hb = to_cxl_host_bridge(host, match);
399 
400 	if (!hb)
401 		return 0;
402 
403 	rc = cxl_get_chbs(match, hb, &ctx);
404 	if (rc)
405 		return rc;
406 
407 	if (ctx.cxl_version == UINT_MAX) {
408 		dev_warn(match, "No CHBS found for Host Bridge (UID %lld)\n",
409 			 ctx.uid);
410 		return 0;
411 	}
412 
413 	if (ctx.base == CXL_RESOURCE_NONE) {
414 		dev_warn(match, "CHBS invalid for Host Bridge (UID %lld)\n",
415 			 ctx.uid);
416 		return 0;
417 	}
418 
419 	pci_root = acpi_pci_find_root(hb->handle);
420 	bridge = pci_root->bus->bridge;
421 
422 	/*
423 	 * In RCH mode, bind the component regs base to the dport. In
424 	 * VH mode it will be bound to the CXL host bridge's port
425 	 * object later in add_host_bridge_uport().
426 	 */
427 	if (ctx.cxl_version == ACPI_CEDT_CHBS_VERSION_CXL11) {
428 		dev_dbg(match, "RCRB found for UID %lld: %pa\n", ctx.uid,
429 			&ctx.base);
430 		dport = devm_cxl_add_rch_dport(root_port, bridge, ctx.uid,
431 					       ctx.base);
432 	} else {
433 		dport = devm_cxl_add_dport(root_port, bridge, ctx.uid,
434 					   CXL_RESOURCE_NONE);
435 	}
436 
437 	if (IS_ERR(dport))
438 		return PTR_ERR(dport);
439 
440 	return 0;
441 }
442 
443 /*
444  * A host bridge is a dport to a CFMWS decode and it is a uport to the
445  * dport (PCIe Root Ports) in the host bridge.
446  */
447 static int add_host_bridge_uport(struct device *match, void *arg)
448 {
449 	struct cxl_port *root_port = arg;
450 	struct device *host = root_port->dev.parent;
451 	struct acpi_device *hb = to_cxl_host_bridge(host, match);
452 	struct acpi_pci_root *pci_root;
453 	struct cxl_dport *dport;
454 	struct cxl_port *port;
455 	struct device *bridge;
456 	struct cxl_chbs_context ctx;
457 	resource_size_t component_reg_phys;
458 	int rc;
459 
460 	if (!hb)
461 		return 0;
462 
463 	pci_root = acpi_pci_find_root(hb->handle);
464 	bridge = pci_root->bus->bridge;
465 	dport = cxl_find_dport_by_dev(root_port, bridge);
466 	if (!dport) {
467 		dev_dbg(host, "host bridge expected and not found\n");
468 		return 0;
469 	}
470 
471 	if (dport->rch) {
472 		dev_info(bridge, "host supports CXL (restricted)\n");
473 		return 0;
474 	}
475 
476 	rc = cxl_get_chbs(match, hb, &ctx);
477 	if (rc)
478 		return rc;
479 
480 	if (ctx.cxl_version == ACPI_CEDT_CHBS_VERSION_CXL11) {
481 		dev_warn(bridge,
482 			 "CXL CHBS version mismatch, skip port registration\n");
483 		return 0;
484 	}
485 
486 	component_reg_phys = ctx.base;
487 	if (component_reg_phys != CXL_RESOURCE_NONE)
488 		dev_dbg(match, "CHBCR found for UID %lld: %pa\n",
489 			ctx.uid, &component_reg_phys);
490 
491 	rc = devm_cxl_register_pci_bus(host, bridge, pci_root->bus);
492 	if (rc)
493 		return rc;
494 
495 	port = devm_cxl_add_port(host, bridge, component_reg_phys, dport);
496 	if (IS_ERR(port))
497 		return PTR_ERR(port);
498 
499 	dev_info(bridge, "host supports CXL\n");
500 
501 	return 0;
502 }
503 
504 static int add_root_nvdimm_bridge(struct device *match, void *data)
505 {
506 	struct cxl_decoder *cxld;
507 	struct cxl_port *root_port = data;
508 	struct cxl_nvdimm_bridge *cxl_nvb;
509 	struct device *host = root_port->dev.parent;
510 
511 	if (!is_root_decoder(match))
512 		return 0;
513 
514 	cxld = to_cxl_decoder(match);
515 	if (!(cxld->flags & CXL_DECODER_F_PMEM))
516 		return 0;
517 
518 	cxl_nvb = devm_cxl_add_nvdimm_bridge(host, root_port);
519 	if (IS_ERR(cxl_nvb)) {
520 		dev_dbg(host, "failed to register pmem\n");
521 		return PTR_ERR(cxl_nvb);
522 	}
523 	dev_dbg(host, "%s: add: %s\n", dev_name(&root_port->dev),
524 		dev_name(&cxl_nvb->dev));
525 	return 1;
526 }
527 
528 static struct lock_class_key cxl_root_key;
529 
530 static void cxl_acpi_lock_reset_class(void *dev)
531 {
532 	device_lock_reset_class(dev);
533 }
534 
535 static void del_cxl_resource(struct resource *res)
536 {
537 	kfree(res->name);
538 	kfree(res);
539 }
540 
541 static void cxl_set_public_resource(struct resource *priv, struct resource *pub)
542 {
543 	priv->desc = (unsigned long) pub;
544 }
545 
546 static struct resource *cxl_get_public_resource(struct resource *priv)
547 {
548 	return (struct resource *) priv->desc;
549 }
550 
551 static void remove_cxl_resources(void *data)
552 {
553 	struct resource *res, *next, *cxl = data;
554 
555 	for (res = cxl->child; res; res = next) {
556 		struct resource *victim = cxl_get_public_resource(res);
557 
558 		next = res->sibling;
559 		remove_resource(res);
560 
561 		if (victim) {
562 			remove_resource(victim);
563 			kfree(victim);
564 		}
565 
566 		del_cxl_resource(res);
567 	}
568 }
569 
570 /**
571  * add_cxl_resources() - reflect CXL fixed memory windows in iomem_resource
572  * @cxl_res: A standalone resource tree where each CXL window is a sibling
573  *
574  * Walk each CXL window in @cxl_res and add it to iomem_resource potentially
575  * expanding its boundaries to ensure that any conflicting resources become
576  * children. If a window is expanded it may then conflict with a another window
577  * entry and require the window to be truncated or trimmed. Consider this
578  * situation:
579  *
580  * |-- "CXL Window 0" --||----- "CXL Window 1" -----|
581  * |--------------- "System RAM" -------------|
582  *
583  * ...where platform firmware has established as System RAM resource across 2
584  * windows, but has left some portion of window 1 for dynamic CXL region
585  * provisioning. In this case "Window 0" will span the entirety of the "System
586  * RAM" span, and "CXL Window 1" is truncated to the remaining tail past the end
587  * of that "System RAM" resource.
588  */
589 static int add_cxl_resources(struct resource *cxl_res)
590 {
591 	struct resource *res, *new, *next;
592 
593 	for (res = cxl_res->child; res; res = next) {
594 		new = kzalloc(sizeof(*new), GFP_KERNEL);
595 		if (!new)
596 			return -ENOMEM;
597 		new->name = res->name;
598 		new->start = res->start;
599 		new->end = res->end;
600 		new->flags = IORESOURCE_MEM;
601 		new->desc = IORES_DESC_CXL;
602 
603 		/*
604 		 * Record the public resource in the private cxl_res tree for
605 		 * later removal.
606 		 */
607 		cxl_set_public_resource(res, new);
608 
609 		insert_resource_expand_to_fit(&iomem_resource, new);
610 
611 		next = res->sibling;
612 		while (next && resource_overlaps(new, next)) {
613 			if (resource_contains(new, next)) {
614 				struct resource *_next = next->sibling;
615 
616 				remove_resource(next);
617 				del_cxl_resource(next);
618 				next = _next;
619 			} else
620 				next->start = new->end + 1;
621 		}
622 	}
623 	return 0;
624 }
625 
626 static int pair_cxl_resource(struct device *dev, void *data)
627 {
628 	struct resource *cxl_res = data;
629 	struct resource *p;
630 
631 	if (!is_root_decoder(dev))
632 		return 0;
633 
634 	for (p = cxl_res->child; p; p = p->sibling) {
635 		struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
636 		struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
637 		struct resource res = {
638 			.start = cxld->hpa_range.start,
639 			.end = cxld->hpa_range.end,
640 			.flags = IORESOURCE_MEM,
641 		};
642 
643 		if (resource_contains(p, &res)) {
644 			cxlrd->res = cxl_get_public_resource(p);
645 			break;
646 		}
647 	}
648 
649 	return 0;
650 }
651 
652 static int cxl_acpi_probe(struct platform_device *pdev)
653 {
654 	int rc;
655 	struct resource *cxl_res;
656 	struct cxl_port *root_port;
657 	struct device *host = &pdev->dev;
658 	struct acpi_device *adev = ACPI_COMPANION(host);
659 	struct cxl_cfmws_context ctx;
660 
661 	device_lock_set_class(&pdev->dev, &cxl_root_key);
662 	rc = devm_add_action_or_reset(&pdev->dev, cxl_acpi_lock_reset_class,
663 				      &pdev->dev);
664 	if (rc)
665 		return rc;
666 
667 	cxl_res = devm_kzalloc(host, sizeof(*cxl_res), GFP_KERNEL);
668 	if (!cxl_res)
669 		return -ENOMEM;
670 	cxl_res->name = "CXL mem";
671 	cxl_res->start = 0;
672 	cxl_res->end = -1;
673 	cxl_res->flags = IORESOURCE_MEM;
674 
675 	root_port = devm_cxl_add_port(host, host, CXL_RESOURCE_NONE, NULL);
676 	if (IS_ERR(root_port))
677 		return PTR_ERR(root_port);
678 
679 	rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
680 			      add_host_bridge_dport);
681 	if (rc < 0)
682 		return rc;
683 
684 	rc = devm_add_action_or_reset(host, remove_cxl_resources, cxl_res);
685 	if (rc)
686 		return rc;
687 
688 	ctx = (struct cxl_cfmws_context) {
689 		.dev = host,
690 		.root_port = root_port,
691 		.cxl_res = cxl_res,
692 	};
693 	rc = acpi_table_parse_cedt(ACPI_CEDT_TYPE_CFMWS, cxl_parse_cfmws, &ctx);
694 	if (rc < 0)
695 		return -ENXIO;
696 
697 	rc = add_cxl_resources(cxl_res);
698 	if (rc)
699 		return rc;
700 
701 	/*
702 	 * Populate the root decoders with their related iomem resource,
703 	 * if present
704 	 */
705 	device_for_each_child(&root_port->dev, cxl_res, pair_cxl_resource);
706 
707 	/*
708 	 * Root level scanned with host-bridge as dports, now scan host-bridges
709 	 * for their role as CXL uports to their CXL-capable PCIe Root Ports.
710 	 */
711 	rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
712 			      add_host_bridge_uport);
713 	if (rc < 0)
714 		return rc;
715 
716 	if (IS_ENABLED(CONFIG_CXL_PMEM))
717 		rc = device_for_each_child(&root_port->dev, root_port,
718 					   add_root_nvdimm_bridge);
719 	if (rc < 0)
720 		return rc;
721 
722 	/* In case PCI is scanned before ACPI re-trigger memdev attach */
723 	cxl_bus_rescan();
724 	return 0;
725 }
726 
727 static const struct acpi_device_id cxl_acpi_ids[] = {
728 	{ "ACPI0017" },
729 	{ },
730 };
731 MODULE_DEVICE_TABLE(acpi, cxl_acpi_ids);
732 
733 static const struct platform_device_id cxl_test_ids[] = {
734 	{ "cxl_acpi" },
735 	{ },
736 };
737 MODULE_DEVICE_TABLE(platform, cxl_test_ids);
738 
739 static struct platform_driver cxl_acpi_driver = {
740 	.probe = cxl_acpi_probe,
741 	.driver = {
742 		.name = KBUILD_MODNAME,
743 		.acpi_match_table = cxl_acpi_ids,
744 	},
745 	.id_table = cxl_test_ids,
746 };
747 
748 static int __init cxl_acpi_init(void)
749 {
750 	return platform_driver_register(&cxl_acpi_driver);
751 }
752 
753 static void __exit cxl_acpi_exit(void)
754 {
755 	platform_driver_unregister(&cxl_acpi_driver);
756 	cxl_bus_drain();
757 }
758 
759 /* load before dax_hmem sees 'Soft Reserved' CXL ranges */
760 subsys_initcall(cxl_acpi_init);
761 module_exit(cxl_acpi_exit);
762 MODULE_LICENSE("GPL v2");
763 MODULE_IMPORT_NS(CXL);
764 MODULE_IMPORT_NS(ACPI);
765