xref: /linux/drivers/cxl/pmem.c (revision 23c48a124b469cee2eb0c75e6d22d366d1caa118)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright(c) 2021 Intel Corporation. All rights reserved. */
3 #include <linux/libnvdimm.h>
4 #include <asm/unaligned.h>
5 #include <linux/device.h>
6 #include <linux/module.h>
7 #include <linux/ndctl.h>
8 #include <linux/async.h>
9 #include <linux/slab.h>
10 #include <linux/nd.h>
11 #include "cxlmem.h"
12 #include "cxl.h"
13 
14 /*
15  * Ordered workqueue for cxl nvdimm device arrival and departure
16  * to coordinate bus rescans when a bridge arrives and trigger remove
17  * operations when the bridge is removed.
18  */
19 static struct workqueue_struct *cxl_pmem_wq;
20 
21 static __read_mostly DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX);
22 
23 static void clear_exclusive(void *cxlds)
24 {
25 	clear_exclusive_cxl_commands(cxlds, exclusive_cmds);
26 }
27 
28 static void unregister_nvdimm(void *nvdimm)
29 {
30 	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
31 	struct cxl_nvdimm_bridge *cxl_nvb = cxl_nvd->bridge;
32 	struct cxl_pmem_region *cxlr_pmem;
33 
34 	device_lock(&cxl_nvb->dev);
35 	cxlr_pmem = cxl_nvd->region;
36 	dev_set_drvdata(&cxl_nvd->dev, NULL);
37 	cxl_nvd->region = NULL;
38 	device_unlock(&cxl_nvb->dev);
39 
40 	if (cxlr_pmem) {
41 		device_release_driver(&cxlr_pmem->dev);
42 		put_device(&cxlr_pmem->dev);
43 	}
44 
45 	nvdimm_delete(nvdimm);
46 	cxl_nvd->bridge = NULL;
47 }
48 
49 static int cxl_nvdimm_probe(struct device *dev)
50 {
51 	struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
52 	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
53 	unsigned long flags = 0, cmd_mask = 0;
54 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
55 	struct cxl_nvdimm_bridge *cxl_nvb;
56 	struct nvdimm *nvdimm;
57 	int rc;
58 
59 	cxl_nvb = cxl_find_nvdimm_bridge(dev);
60 	if (!cxl_nvb)
61 		return -ENXIO;
62 
63 	device_lock(&cxl_nvb->dev);
64 	if (!cxl_nvb->nvdimm_bus) {
65 		rc = -ENXIO;
66 		goto out;
67 	}
68 
69 	set_exclusive_cxl_commands(cxlds, exclusive_cmds);
70 	rc = devm_add_action_or_reset(dev, clear_exclusive, cxlds);
71 	if (rc)
72 		goto out;
73 
74 	set_bit(NDD_LABELING, &flags);
75 	set_bit(ND_CMD_GET_CONFIG_SIZE, &cmd_mask);
76 	set_bit(ND_CMD_GET_CONFIG_DATA, &cmd_mask);
77 	set_bit(ND_CMD_SET_CONFIG_DATA, &cmd_mask);
78 	nvdimm = nvdimm_create(cxl_nvb->nvdimm_bus, cxl_nvd, NULL, flags,
79 			       cmd_mask, 0, NULL);
80 	if (!nvdimm) {
81 		rc = -ENOMEM;
82 		goto out;
83 	}
84 
85 	dev_set_drvdata(dev, nvdimm);
86 	cxl_nvd->bridge = cxl_nvb;
87 	rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm);
88 out:
89 	device_unlock(&cxl_nvb->dev);
90 	put_device(&cxl_nvb->dev);
91 
92 	return rc;
93 }
94 
95 static struct cxl_driver cxl_nvdimm_driver = {
96 	.name = "cxl_nvdimm",
97 	.probe = cxl_nvdimm_probe,
98 	.id = CXL_DEVICE_NVDIMM,
99 };
100 
101 static int cxl_pmem_get_config_size(struct cxl_dev_state *cxlds,
102 				    struct nd_cmd_get_config_size *cmd,
103 				    unsigned int buf_len)
104 {
105 	if (sizeof(*cmd) > buf_len)
106 		return -EINVAL;
107 
108 	*cmd = (struct nd_cmd_get_config_size) {
109 		 .config_size = cxlds->lsa_size,
110 		 .max_xfer = cxlds->payload_size,
111 	};
112 
113 	return 0;
114 }
115 
116 static int cxl_pmem_get_config_data(struct cxl_dev_state *cxlds,
117 				    struct nd_cmd_get_config_data_hdr *cmd,
118 				    unsigned int buf_len)
119 {
120 	struct cxl_mbox_get_lsa get_lsa;
121 	int rc;
122 
123 	if (sizeof(*cmd) > buf_len)
124 		return -EINVAL;
125 	if (struct_size(cmd, out_buf, cmd->in_length) > buf_len)
126 		return -EINVAL;
127 
128 	get_lsa = (struct cxl_mbox_get_lsa) {
129 		.offset = cpu_to_le32(cmd->in_offset),
130 		.length = cpu_to_le32(cmd->in_length),
131 	};
132 
133 	rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_GET_LSA, &get_lsa,
134 			       sizeof(get_lsa), cmd->out_buf, cmd->in_length);
135 	cmd->status = 0;
136 
137 	return rc;
138 }
139 
140 static int cxl_pmem_set_config_data(struct cxl_dev_state *cxlds,
141 				    struct nd_cmd_set_config_hdr *cmd,
142 				    unsigned int buf_len)
143 {
144 	struct cxl_mbox_set_lsa *set_lsa;
145 	int rc;
146 
147 	if (sizeof(*cmd) > buf_len)
148 		return -EINVAL;
149 
150 	/* 4-byte status follows the input data in the payload */
151 	if (struct_size(cmd, in_buf, cmd->in_length) + 4 > buf_len)
152 		return -EINVAL;
153 
154 	set_lsa =
155 		kvzalloc(struct_size(set_lsa, data, cmd->in_length), GFP_KERNEL);
156 	if (!set_lsa)
157 		return -ENOMEM;
158 
159 	*set_lsa = (struct cxl_mbox_set_lsa) {
160 		.offset = cpu_to_le32(cmd->in_offset),
161 	};
162 	memcpy(set_lsa->data, cmd->in_buf, cmd->in_length);
163 
164 	rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_SET_LSA, set_lsa,
165 			       struct_size(set_lsa, data, cmd->in_length),
166 			       NULL, 0);
167 
168 	/*
169 	 * Set "firmware" status (4-packed bytes at the end of the input
170 	 * payload.
171 	 */
172 	put_unaligned(0, (u32 *) &cmd->in_buf[cmd->in_length]);
173 	kvfree(set_lsa);
174 
175 	return rc;
176 }
177 
178 static int cxl_pmem_nvdimm_ctl(struct nvdimm *nvdimm, unsigned int cmd,
179 			       void *buf, unsigned int buf_len)
180 {
181 	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
182 	unsigned long cmd_mask = nvdimm_cmd_mask(nvdimm);
183 	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
184 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
185 
186 	if (!test_bit(cmd, &cmd_mask))
187 		return -ENOTTY;
188 
189 	switch (cmd) {
190 	case ND_CMD_GET_CONFIG_SIZE:
191 		return cxl_pmem_get_config_size(cxlds, buf, buf_len);
192 	case ND_CMD_GET_CONFIG_DATA:
193 		return cxl_pmem_get_config_data(cxlds, buf, buf_len);
194 	case ND_CMD_SET_CONFIG_DATA:
195 		return cxl_pmem_set_config_data(cxlds, buf, buf_len);
196 	default:
197 		return -ENOTTY;
198 	}
199 }
200 
201 static int cxl_pmem_ctl(struct nvdimm_bus_descriptor *nd_desc,
202 			struct nvdimm *nvdimm, unsigned int cmd, void *buf,
203 			unsigned int buf_len, int *cmd_rc)
204 {
205 	/*
206 	 * No firmware response to translate, let the transport error
207 	 * code take precedence.
208 	 */
209 	*cmd_rc = 0;
210 
211 	if (!nvdimm)
212 		return -ENOTTY;
213 	return cxl_pmem_nvdimm_ctl(nvdimm, cmd, buf, buf_len);
214 }
215 
216 static bool online_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb)
217 {
218 	if (cxl_nvb->nvdimm_bus)
219 		return true;
220 	cxl_nvb->nvdimm_bus =
221 		nvdimm_bus_register(&cxl_nvb->dev, &cxl_nvb->nd_desc);
222 	return cxl_nvb->nvdimm_bus != NULL;
223 }
224 
225 static int cxl_nvdimm_release_driver(struct device *dev, void *cxl_nvb)
226 {
227 	struct cxl_nvdimm *cxl_nvd;
228 
229 	if (!is_cxl_nvdimm(dev))
230 		return 0;
231 
232 	cxl_nvd = to_cxl_nvdimm(dev);
233 	if (cxl_nvd->bridge != cxl_nvb)
234 		return 0;
235 
236 	device_release_driver(dev);
237 	return 0;
238 }
239 
240 static int cxl_pmem_region_release_driver(struct device *dev, void *cxl_nvb)
241 {
242 	struct cxl_pmem_region *cxlr_pmem;
243 
244 	if (!is_cxl_pmem_region(dev))
245 		return 0;
246 
247 	cxlr_pmem = to_cxl_pmem_region(dev);
248 	if (cxlr_pmem->bridge != cxl_nvb)
249 		return 0;
250 
251 	device_release_driver(dev);
252 	return 0;
253 }
254 
255 static void offline_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb,
256 			       struct nvdimm_bus *nvdimm_bus)
257 {
258 	if (!nvdimm_bus)
259 		return;
260 
261 	/*
262 	 * Set the state of cxl_nvdimm devices to unbound / idle before
263 	 * nvdimm_bus_unregister() rips the nvdimm objects out from
264 	 * underneath them.
265 	 */
266 	bus_for_each_dev(&cxl_bus_type, NULL, cxl_nvb,
267 			 cxl_pmem_region_release_driver);
268 	bus_for_each_dev(&cxl_bus_type, NULL, cxl_nvb,
269 			 cxl_nvdimm_release_driver);
270 	nvdimm_bus_unregister(nvdimm_bus);
271 }
272 
273 static void cxl_nvb_update_state(struct work_struct *work)
274 {
275 	struct cxl_nvdimm_bridge *cxl_nvb =
276 		container_of(work, typeof(*cxl_nvb), state_work);
277 	struct nvdimm_bus *victim_bus = NULL;
278 	bool release = false, rescan = false;
279 
280 	device_lock(&cxl_nvb->dev);
281 	switch (cxl_nvb->state) {
282 	case CXL_NVB_ONLINE:
283 		if (!online_nvdimm_bus(cxl_nvb)) {
284 			dev_err(&cxl_nvb->dev,
285 				"failed to establish nvdimm bus\n");
286 			release = true;
287 		} else
288 			rescan = true;
289 		break;
290 	case CXL_NVB_OFFLINE:
291 	case CXL_NVB_DEAD:
292 		victim_bus = cxl_nvb->nvdimm_bus;
293 		cxl_nvb->nvdimm_bus = NULL;
294 		break;
295 	default:
296 		break;
297 	}
298 	device_unlock(&cxl_nvb->dev);
299 
300 	if (release)
301 		device_release_driver(&cxl_nvb->dev);
302 	if (rescan) {
303 		int rc = bus_rescan_devices(&cxl_bus_type);
304 
305 		dev_dbg(&cxl_nvb->dev, "rescan: %d\n", rc);
306 	}
307 	offline_nvdimm_bus(cxl_nvb, victim_bus);
308 
309 	put_device(&cxl_nvb->dev);
310 }
311 
312 static void cxl_nvdimm_bridge_state_work(struct cxl_nvdimm_bridge *cxl_nvb)
313 {
314 	/*
315 	 * Take a reference that the workqueue will drop if new work
316 	 * gets queued.
317 	 */
318 	get_device(&cxl_nvb->dev);
319 	if (!queue_work(cxl_pmem_wq, &cxl_nvb->state_work))
320 		put_device(&cxl_nvb->dev);
321 }
322 
323 static void cxl_nvdimm_bridge_remove(struct device *dev)
324 {
325 	struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
326 
327 	if (cxl_nvb->state == CXL_NVB_ONLINE)
328 		cxl_nvb->state = CXL_NVB_OFFLINE;
329 	cxl_nvdimm_bridge_state_work(cxl_nvb);
330 }
331 
332 static int cxl_nvdimm_bridge_probe(struct device *dev)
333 {
334 	struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
335 
336 	if (cxl_nvb->state == CXL_NVB_DEAD)
337 		return -ENXIO;
338 
339 	if (cxl_nvb->state == CXL_NVB_NEW) {
340 		cxl_nvb->nd_desc = (struct nvdimm_bus_descriptor) {
341 			.provider_name = "CXL",
342 			.module = THIS_MODULE,
343 			.ndctl = cxl_pmem_ctl,
344 		};
345 
346 		INIT_WORK(&cxl_nvb->state_work, cxl_nvb_update_state);
347 	}
348 
349 	cxl_nvb->state = CXL_NVB_ONLINE;
350 	cxl_nvdimm_bridge_state_work(cxl_nvb);
351 
352 	return 0;
353 }
354 
355 static struct cxl_driver cxl_nvdimm_bridge_driver = {
356 	.name = "cxl_nvdimm_bridge",
357 	.probe = cxl_nvdimm_bridge_probe,
358 	.remove = cxl_nvdimm_bridge_remove,
359 	.id = CXL_DEVICE_NVDIMM_BRIDGE,
360 };
361 
362 static int match_cxl_nvdimm(struct device *dev, void *data)
363 {
364 	return is_cxl_nvdimm(dev);
365 }
366 
367 static void unregister_nvdimm_region(void *nd_region)
368 {
369 	struct cxl_nvdimm_bridge *cxl_nvb;
370 	struct cxl_pmem_region *cxlr_pmem;
371 	int i;
372 
373 	cxlr_pmem = nd_region_provider_data(nd_region);
374 	cxl_nvb = cxlr_pmem->bridge;
375 	device_lock(&cxl_nvb->dev);
376 	for (i = 0; i < cxlr_pmem->nr_mappings; i++) {
377 		struct cxl_pmem_region_mapping *m = &cxlr_pmem->mapping[i];
378 		struct cxl_nvdimm *cxl_nvd = m->cxl_nvd;
379 
380 		if (cxl_nvd->region) {
381 			put_device(&cxlr_pmem->dev);
382 			cxl_nvd->region = NULL;
383 		}
384 	}
385 	device_unlock(&cxl_nvb->dev);
386 
387 	nvdimm_region_delete(nd_region);
388 }
389 
390 static void cxlr_pmem_remove_resource(void *res)
391 {
392 	remove_resource(res);
393 }
394 
395 struct cxl_pmem_region_info {
396 	u64 offset;
397 	u64 serial;
398 };
399 
400 static int cxl_pmem_region_probe(struct device *dev)
401 {
402 	struct nd_mapping_desc mappings[CXL_DECODER_MAX_INTERLEAVE];
403 	struct cxl_pmem_region *cxlr_pmem = to_cxl_pmem_region(dev);
404 	struct cxl_region *cxlr = cxlr_pmem->cxlr;
405 	struct cxl_pmem_region_info *info = NULL;
406 	struct cxl_nvdimm_bridge *cxl_nvb;
407 	struct nd_interleave_set *nd_set;
408 	struct nd_region_desc ndr_desc;
409 	struct cxl_nvdimm *cxl_nvd;
410 	struct nvdimm *nvdimm;
411 	struct resource *res;
412 	int rc, i = 0;
413 
414 	cxl_nvb = cxl_find_nvdimm_bridge(&cxlr_pmem->mapping[0].cxlmd->dev);
415 	if (!cxl_nvb) {
416 		dev_dbg(dev, "bridge not found\n");
417 		return -ENXIO;
418 	}
419 	cxlr_pmem->bridge = cxl_nvb;
420 
421 	device_lock(&cxl_nvb->dev);
422 	if (!cxl_nvb->nvdimm_bus) {
423 		dev_dbg(dev, "nvdimm bus not found\n");
424 		rc = -ENXIO;
425 		goto err;
426 	}
427 
428 	memset(&mappings, 0, sizeof(mappings));
429 	memset(&ndr_desc, 0, sizeof(ndr_desc));
430 
431 	res = devm_kzalloc(dev, sizeof(*res), GFP_KERNEL);
432 	if (!res) {
433 		rc = -ENOMEM;
434 		goto err;
435 	}
436 
437 	res->name = "Persistent Memory";
438 	res->start = cxlr_pmem->hpa_range.start;
439 	res->end = cxlr_pmem->hpa_range.end;
440 	res->flags = IORESOURCE_MEM;
441 	res->desc = IORES_DESC_PERSISTENT_MEMORY;
442 
443 	rc = insert_resource(&iomem_resource, res);
444 	if (rc)
445 		goto err;
446 
447 	rc = devm_add_action_or_reset(dev, cxlr_pmem_remove_resource, res);
448 	if (rc)
449 		goto err;
450 
451 	ndr_desc.res = res;
452 	ndr_desc.provider_data = cxlr_pmem;
453 
454 	ndr_desc.numa_node = memory_add_physaddr_to_nid(res->start);
455 	ndr_desc.target_node = phys_to_target_node(res->start);
456 	if (ndr_desc.target_node == NUMA_NO_NODE) {
457 		ndr_desc.target_node = ndr_desc.numa_node;
458 		dev_dbg(&cxlr->dev, "changing target node from %d to %d",
459 			NUMA_NO_NODE, ndr_desc.target_node);
460 	}
461 
462 	nd_set = devm_kzalloc(dev, sizeof(*nd_set), GFP_KERNEL);
463 	if (!nd_set) {
464 		rc = -ENOMEM;
465 		goto err;
466 	}
467 
468 	ndr_desc.memregion = cxlr->id;
469 	set_bit(ND_REGION_CXL, &ndr_desc.flags);
470 	set_bit(ND_REGION_PERSIST_MEMCTRL, &ndr_desc.flags);
471 
472 	info = kmalloc_array(cxlr_pmem->nr_mappings, sizeof(*info), GFP_KERNEL);
473 	if (!info) {
474 		rc = -ENOMEM;
475 		goto err;
476 	}
477 
478 	for (i = 0; i < cxlr_pmem->nr_mappings; i++) {
479 		struct cxl_pmem_region_mapping *m = &cxlr_pmem->mapping[i];
480 		struct cxl_memdev *cxlmd = m->cxlmd;
481 		struct cxl_dev_state *cxlds = cxlmd->cxlds;
482 		struct device *d;
483 
484 		d = device_find_child(&cxlmd->dev, NULL, match_cxl_nvdimm);
485 		if (!d) {
486 			dev_dbg(dev, "[%d]: %s: no cxl_nvdimm found\n", i,
487 				dev_name(&cxlmd->dev));
488 			rc = -ENODEV;
489 			goto err;
490 		}
491 
492 		/* safe to drop ref now with bridge lock held */
493 		put_device(d);
494 
495 		cxl_nvd = to_cxl_nvdimm(d);
496 		nvdimm = dev_get_drvdata(&cxl_nvd->dev);
497 		if (!nvdimm) {
498 			dev_dbg(dev, "[%d]: %s: no nvdimm found\n", i,
499 				dev_name(&cxlmd->dev));
500 			rc = -ENODEV;
501 			goto err;
502 		}
503 		cxl_nvd->region = cxlr_pmem;
504 		get_device(&cxlr_pmem->dev);
505 		m->cxl_nvd = cxl_nvd;
506 		mappings[i] = (struct nd_mapping_desc) {
507 			.nvdimm = nvdimm,
508 			.start = m->start,
509 			.size = m->size,
510 			.position = i,
511 		};
512 		info[i].offset = m->start;
513 		info[i].serial = cxlds->serial;
514 	}
515 	ndr_desc.num_mappings = cxlr_pmem->nr_mappings;
516 	ndr_desc.mapping = mappings;
517 
518 	/*
519 	 * TODO enable CXL labels which skip the need for 'interleave-set cookie'
520 	 */
521 	nd_set->cookie1 =
522 		nd_fletcher64(info, sizeof(*info) * cxlr_pmem->nr_mappings, 0);
523 	nd_set->cookie2 = nd_set->cookie1;
524 	ndr_desc.nd_set = nd_set;
525 
526 	cxlr_pmem->nd_region =
527 		nvdimm_pmem_region_create(cxl_nvb->nvdimm_bus, &ndr_desc);
528 	if (!cxlr_pmem->nd_region) {
529 		rc = -ENOMEM;
530 		goto err;
531 	}
532 
533 	rc = devm_add_action_or_reset(dev, unregister_nvdimm_region,
534 				      cxlr_pmem->nd_region);
535 out:
536 	kfree(info);
537 	device_unlock(&cxl_nvb->dev);
538 	put_device(&cxl_nvb->dev);
539 
540 	return rc;
541 
542 err:
543 	dev_dbg(dev, "failed to create nvdimm region\n");
544 	for (i--; i >= 0; i--) {
545 		nvdimm = mappings[i].nvdimm;
546 		cxl_nvd = nvdimm_provider_data(nvdimm);
547 		put_device(&cxl_nvd->region->dev);
548 		cxl_nvd->region = NULL;
549 	}
550 	goto out;
551 }
552 
553 static struct cxl_driver cxl_pmem_region_driver = {
554 	.name = "cxl_pmem_region",
555 	.probe = cxl_pmem_region_probe,
556 	.id = CXL_DEVICE_PMEM_REGION,
557 };
558 
559 /*
560  * Return all bridges to the CXL_NVB_NEW state to invalidate any
561  * ->state_work referring to the now destroyed cxl_pmem_wq.
562  */
563 static int cxl_nvdimm_bridge_reset(struct device *dev, void *data)
564 {
565 	struct cxl_nvdimm_bridge *cxl_nvb;
566 
567 	if (!is_cxl_nvdimm_bridge(dev))
568 		return 0;
569 
570 	cxl_nvb = to_cxl_nvdimm_bridge(dev);
571 	device_lock(dev);
572 	cxl_nvb->state = CXL_NVB_NEW;
573 	device_unlock(dev);
574 
575 	return 0;
576 }
577 
578 static void destroy_cxl_pmem_wq(void)
579 {
580 	destroy_workqueue(cxl_pmem_wq);
581 	bus_for_each_dev(&cxl_bus_type, NULL, NULL, cxl_nvdimm_bridge_reset);
582 }
583 
584 static __init int cxl_pmem_init(void)
585 {
586 	int rc;
587 
588 	set_bit(CXL_MEM_COMMAND_ID_SET_SHUTDOWN_STATE, exclusive_cmds);
589 	set_bit(CXL_MEM_COMMAND_ID_SET_LSA, exclusive_cmds);
590 
591 	cxl_pmem_wq = alloc_ordered_workqueue("cxl_pmem", 0);
592 	if (!cxl_pmem_wq)
593 		return -ENXIO;
594 
595 	rc = cxl_driver_register(&cxl_nvdimm_bridge_driver);
596 	if (rc)
597 		goto err_bridge;
598 
599 	rc = cxl_driver_register(&cxl_nvdimm_driver);
600 	if (rc)
601 		goto err_nvdimm;
602 
603 	rc = cxl_driver_register(&cxl_pmem_region_driver);
604 	if (rc)
605 		goto err_region;
606 
607 	return 0;
608 
609 err_region:
610 	cxl_driver_unregister(&cxl_nvdimm_driver);
611 err_nvdimm:
612 	cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
613 err_bridge:
614 	destroy_cxl_pmem_wq();
615 	return rc;
616 }
617 
618 static __exit void cxl_pmem_exit(void)
619 {
620 	cxl_driver_unregister(&cxl_pmem_region_driver);
621 	cxl_driver_unregister(&cxl_nvdimm_driver);
622 	cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
623 	destroy_cxl_pmem_wq();
624 }
625 
626 MODULE_LICENSE("GPL v2");
627 module_init(cxl_pmem_init);
628 module_exit(cxl_pmem_exit);
629 MODULE_IMPORT_NS(CXL);
630 MODULE_ALIAS_CXL(CXL_DEVICE_NVDIMM_BRIDGE);
631 MODULE_ALIAS_CXL(CXL_DEVICE_NVDIMM);
632 MODULE_ALIAS_CXL(CXL_DEVICE_PMEM_REGION);
633