xref: /linux/drivers/cxl/core/features.c (revision 570f7e331f5febb30f1384817463c7e42b65ca7d)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright(c) 2024-2025 Intel Corporation. All rights reserved. */
3 #include <linux/fwctl.h>
4 #include <linux/device.h>
5 #include <cxl/mailbox.h>
6 #include <cxl/features.h>
7 #include <uapi/fwctl/cxl.h>
8 #include "cxl.h"
9 #include "core.h"
10 #include "cxlmem.h"
11 
12 /**
13  * DOC: cxl features
14  *
15  * CXL Features:
16  * A CXL device that includes a mailbox supports commands that allows
17  * listing, getting, and setting of optionally defined features such
18  * as memory sparing or post package sparing. Vendors may define custom
19  * features for the device.
20  */
21 
22 /* All the features below are exclusive to the kernel */
23 static const uuid_t cxl_exclusive_feats[] = {
24 	CXL_FEAT_PATROL_SCRUB_UUID,
25 	CXL_FEAT_ECS_UUID,
26 	CXL_FEAT_SPPR_UUID,
27 	CXL_FEAT_HPPR_UUID,
28 	CXL_FEAT_CACHELINE_SPARING_UUID,
29 	CXL_FEAT_ROW_SPARING_UUID,
30 	CXL_FEAT_BANK_SPARING_UUID,
31 	CXL_FEAT_RANK_SPARING_UUID,
32 };
33 
34 static bool is_cxl_feature_exclusive_by_uuid(const uuid_t *uuid)
35 {
36 	for (int i = 0; i < ARRAY_SIZE(cxl_exclusive_feats); i++) {
37 		if (uuid_equal(uuid, &cxl_exclusive_feats[i]))
38 			return true;
39 	}
40 
41 	return false;
42 }
43 
44 static bool is_cxl_feature_exclusive(struct cxl_feat_entry *entry)
45 {
46 	return is_cxl_feature_exclusive_by_uuid(&entry->uuid);
47 }
48 
49 struct cxl_features_state *to_cxlfs(struct cxl_dev_state *cxlds)
50 {
51 	return cxlds->cxlfs;
52 }
53 EXPORT_SYMBOL_NS_GPL(to_cxlfs, "CXL");
54 
55 static int cxl_get_supported_features_count(struct cxl_mailbox *cxl_mbox)
56 {
57 	struct cxl_mbox_get_sup_feats_out mbox_out;
58 	struct cxl_mbox_get_sup_feats_in mbox_in;
59 	struct cxl_mbox_cmd mbox_cmd;
60 	int rc;
61 
62 	memset(&mbox_in, 0, sizeof(mbox_in));
63 	mbox_in.count = cpu_to_le32(sizeof(mbox_out));
64 	memset(&mbox_out, 0, sizeof(mbox_out));
65 	mbox_cmd = (struct cxl_mbox_cmd) {
66 		.opcode = CXL_MBOX_OP_GET_SUPPORTED_FEATURES,
67 		.size_in = sizeof(mbox_in),
68 		.payload_in = &mbox_in,
69 		.size_out = sizeof(mbox_out),
70 		.payload_out = &mbox_out,
71 		.min_out = sizeof(mbox_out),
72 	};
73 	rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
74 	if (rc < 0)
75 		return rc;
76 
77 	return le16_to_cpu(mbox_out.supported_feats);
78 }
79 
80 static struct cxl_feat_entries *
81 get_supported_features(struct cxl_features_state *cxlfs)
82 {
83 	int remain_feats, max_size, max_feats, start, rc, hdr_size;
84 	struct cxl_mailbox *cxl_mbox = &cxlfs->cxlds->cxl_mbox;
85 	int feat_size = sizeof(struct cxl_feat_entry);
86 	struct cxl_mbox_get_sup_feats_in mbox_in;
87 	struct cxl_feat_entry *entry;
88 	struct cxl_mbox_cmd mbox_cmd;
89 	int user_feats = 0;
90 	int count;
91 
92 	count = cxl_get_supported_features_count(cxl_mbox);
93 	if (count <= 0)
94 		return NULL;
95 
96 	struct cxl_feat_entries *entries __free(kvfree) =
97 		kvmalloc_flex(*entries, ent, count);
98 	if (!entries)
99 		return NULL;
100 
101 	struct cxl_mbox_get_sup_feats_out *mbox_out __free(kvfree) =
102 		kvmalloc(cxl_mbox->payload_size, GFP_KERNEL);
103 	if (!mbox_out)
104 		return NULL;
105 
106 	hdr_size = struct_size(mbox_out, ents, 0);
107 	max_size = cxl_mbox->payload_size - hdr_size;
108 	/* max feat entries that can fit in mailbox max payload size */
109 	max_feats = max_size / feat_size;
110 	entry = entries->ent;
111 
112 	start = 0;
113 	remain_feats = count;
114 	do {
115 		int retrieved, alloc_size, copy_feats;
116 		int num_entries;
117 
118 		if (remain_feats > max_feats) {
119 			alloc_size = struct_size(mbox_out, ents, max_feats);
120 			remain_feats = remain_feats - max_feats;
121 			copy_feats = max_feats;
122 		} else {
123 			alloc_size = struct_size(mbox_out, ents, remain_feats);
124 			copy_feats = remain_feats;
125 			remain_feats = 0;
126 		}
127 
128 		memset(&mbox_in, 0, sizeof(mbox_in));
129 		mbox_in.count = cpu_to_le32(alloc_size);
130 		mbox_in.start_idx = cpu_to_le16(start);
131 		memset(mbox_out, 0, alloc_size);
132 		mbox_cmd = (struct cxl_mbox_cmd) {
133 			.opcode = CXL_MBOX_OP_GET_SUPPORTED_FEATURES,
134 			.size_in = sizeof(mbox_in),
135 			.payload_in = &mbox_in,
136 			.size_out = alloc_size,
137 			.payload_out = mbox_out,
138 			.min_out = hdr_size,
139 		};
140 		rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
141 		if (rc < 0)
142 			return NULL;
143 
144 		if (mbox_cmd.size_out <= hdr_size)
145 			return NULL;
146 
147 		/*
148 		 * Make sure retrieved out buffer is multiple of feature
149 		 * entries.
150 		 */
151 		retrieved = mbox_cmd.size_out - hdr_size;
152 		if (retrieved % feat_size)
153 			return NULL;
154 
155 		num_entries = le16_to_cpu(mbox_out->num_entries);
156 		/*
157 		 * If the reported output entries * defined entry size !=
158 		 * retrieved output bytes, then the output package is incorrect.
159 		 */
160 		if (num_entries * feat_size != retrieved)
161 			return NULL;
162 
163 		memcpy(entry, mbox_out->ents, retrieved);
164 		for (int i = 0; i < num_entries; i++) {
165 			if (!is_cxl_feature_exclusive(entry + i))
166 				user_feats++;
167 		}
168 		entry += num_entries;
169 		/*
170 		 * If the number of output entries is less than expected, add the
171 		 * remaining entries to the next batch.
172 		 */
173 		remain_feats += copy_feats - num_entries;
174 		start += num_entries;
175 	} while (remain_feats);
176 
177 	entries->num_features = count;
178 	entries->num_user_features = user_feats;
179 
180 	return no_free_ptr(entries);
181 }
182 
183 static void free_cxlfs(void *_cxlfs)
184 {
185 	struct cxl_features_state *cxlfs = _cxlfs;
186 	struct cxl_dev_state *cxlds = cxlfs->cxlds;
187 
188 	cxlds->cxlfs = NULL;
189 	kvfree(cxlfs->entries);
190 	kfree(cxlfs);
191 }
192 
193 /**
194  * devm_cxl_setup_features() - Allocate and initialize features context
195  * @cxlds: CXL device context
196  *
197  * Return 0 on success or -errno on failure.
198  */
199 int devm_cxl_setup_features(struct cxl_dev_state *cxlds)
200 {
201 	struct cxl_mailbox *cxl_mbox = &cxlds->cxl_mbox;
202 
203 	if (cxl_mbox->feat_cap < CXL_FEATURES_RO)
204 		return -ENODEV;
205 
206 	struct cxl_features_state *cxlfs __free(kfree) =
207 		kzalloc_obj(*cxlfs);
208 	if (!cxlfs)
209 		return -ENOMEM;
210 
211 	cxlfs->cxlds = cxlds;
212 
213 	cxlfs->entries = get_supported_features(cxlfs);
214 	if (!cxlfs->entries)
215 		return -ENOMEM;
216 
217 	cxlds->cxlfs = cxlfs;
218 
219 	return devm_add_action_or_reset(cxlds->dev, free_cxlfs, no_free_ptr(cxlfs));
220 }
221 EXPORT_SYMBOL_NS_GPL(devm_cxl_setup_features, "CXL");
222 
223 size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
224 		       enum cxl_get_feat_selection selection,
225 		       void *feat_out, size_t feat_out_size, u16 offset,
226 		       u16 *return_code)
227 {
228 	size_t data_to_rd_size;
229 	struct cxl_mbox_get_feat_in pi;
230 	struct cxl_mbox_cmd mbox_cmd;
231 	size_t data_rcvd_size = 0;
232 	int rc;
233 
234 	if (return_code)
235 		*return_code = CXL_MBOX_CMD_RC_INPUT;
236 
237 	if (!feat_out || !feat_out_size)
238 		return 0;
239 
240 	uuid_copy(&pi.uuid, feat_uuid);
241 	pi.selection = selection;
242 
243 	guard(mutex)(&cxl_mbox->feat_mutex);
244 	do {
245 		data_to_rd_size = min(feat_out_size - data_rcvd_size,
246 				      cxl_mbox->payload_size);
247 		pi.offset = cpu_to_le16(offset + data_rcvd_size);
248 		pi.count = cpu_to_le16(data_to_rd_size);
249 
250 		mbox_cmd = (struct cxl_mbox_cmd) {
251 			.opcode = CXL_MBOX_OP_GET_FEATURE,
252 			.size_in = sizeof(pi),
253 			.payload_in = &pi,
254 			.size_out = data_to_rd_size,
255 			.payload_out = feat_out + data_rcvd_size,
256 			.min_out = data_to_rd_size,
257 		};
258 		rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
259 		if (rc < 0 || !mbox_cmd.size_out) {
260 			if (return_code)
261 				*return_code = mbox_cmd.return_code;
262 			return 0;
263 		}
264 		data_rcvd_size += mbox_cmd.size_out;
265 	} while (data_rcvd_size < feat_out_size);
266 
267 	if (return_code)
268 		*return_code = CXL_MBOX_CMD_RC_SUCCESS;
269 
270 	return data_rcvd_size;
271 }
272 
273 /*
274  * FEAT_DATA_MIN_PAYLOAD_SIZE - min extra number of bytes should be
275  * available in the mailbox for storing the actual feature data so that
276  * the feature data transfer would work as expected.
277  */
278 #define FEAT_DATA_MIN_PAYLOAD_SIZE 10
279 int cxl_set_feature(struct cxl_mailbox *cxl_mbox,
280 		    const uuid_t *feat_uuid, u8 feat_version,
281 		    const void *feat_data, size_t feat_data_size,
282 		    u32 feat_flag, u16 offset, u16 *return_code)
283 {
284 	size_t data_in_size, data_sent_size = 0;
285 	struct cxl_mbox_cmd mbox_cmd;
286 	size_t hdr_size;
287 
288 	if (return_code)
289 		*return_code = CXL_MBOX_CMD_RC_INPUT;
290 
291 	struct cxl_mbox_set_feat_in *pi __free(kfree) =
292 			kzalloc(cxl_mbox->payload_size, GFP_KERNEL);
293 	if (!pi)
294 		return -ENOMEM;
295 
296 	uuid_copy(&pi->uuid, feat_uuid);
297 	pi->version = feat_version;
298 	feat_flag &= ~CXL_SET_FEAT_FLAG_DATA_TRANSFER_MASK;
299 	feat_flag |= CXL_SET_FEAT_FLAG_DATA_SAVED_ACROSS_RESET;
300 	hdr_size = sizeof(pi->hdr);
301 	/*
302 	 * Check minimum mbox payload size is available for
303 	 * the feature data transfer.
304 	 */
305 	if (hdr_size + FEAT_DATA_MIN_PAYLOAD_SIZE > cxl_mbox->payload_size)
306 		return -ENOMEM;
307 
308 	if (hdr_size + feat_data_size <= cxl_mbox->payload_size) {
309 		pi->flags = cpu_to_le32(feat_flag |
310 					CXL_SET_FEAT_FLAG_FULL_DATA_TRANSFER);
311 		data_in_size = feat_data_size;
312 	} else {
313 		pi->flags = cpu_to_le32(feat_flag |
314 					CXL_SET_FEAT_FLAG_INITIATE_DATA_TRANSFER);
315 		data_in_size = cxl_mbox->payload_size - hdr_size;
316 	}
317 
318 	guard(mutex)(&cxl_mbox->feat_mutex);
319 	do {
320 		int rc;
321 
322 		pi->offset = cpu_to_le16(offset + data_sent_size);
323 		memcpy(pi->feat_data, feat_data + data_sent_size, data_in_size);
324 		mbox_cmd = (struct cxl_mbox_cmd) {
325 			.opcode = CXL_MBOX_OP_SET_FEATURE,
326 			.size_in = hdr_size + data_in_size,
327 			.payload_in = pi,
328 		};
329 		rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
330 		if (rc < 0) {
331 			if (return_code)
332 				*return_code = mbox_cmd.return_code;
333 			return rc;
334 		}
335 
336 		data_sent_size += data_in_size;
337 		if (data_sent_size >= feat_data_size) {
338 			if (return_code)
339 				*return_code = CXL_MBOX_CMD_RC_SUCCESS;
340 			return 0;
341 		}
342 
343 		if ((feat_data_size - data_sent_size) <= (cxl_mbox->payload_size - hdr_size)) {
344 			data_in_size = feat_data_size - data_sent_size;
345 			pi->flags = cpu_to_le32(feat_flag |
346 						CXL_SET_FEAT_FLAG_FINISH_DATA_TRANSFER);
347 		} else {
348 			pi->flags = cpu_to_le32(feat_flag |
349 						CXL_SET_FEAT_FLAG_CONTINUE_DATA_TRANSFER);
350 		}
351 	} while (true);
352 }
353 
354 /* FWCTL support */
355 
356 static inline struct cxl_memdev *fwctl_to_memdev(struct fwctl_device *fwctl_dev)
357 {
358 	return to_cxl_memdev(fwctl_dev->dev.parent);
359 }
360 
361 static int cxlctl_open_uctx(struct fwctl_uctx *uctx)
362 {
363 	return 0;
364 }
365 
366 static void cxlctl_close_uctx(struct fwctl_uctx *uctx)
367 {
368 }
369 
370 struct cxl_feat_entry *
371 cxl_feature_info(struct cxl_features_state *cxlfs,
372 		 const uuid_t *uuid)
373 {
374 	struct cxl_feat_entry *feat;
375 
376 	if (!cxlfs || !cxlfs->entries)
377 		return ERR_PTR(-EOPNOTSUPP);
378 
379 	for (int i = 0; i < cxlfs->entries->num_features; i++) {
380 		feat = &cxlfs->entries->ent[i];
381 		if (uuid_equal(uuid, &feat->uuid))
382 			return feat;
383 	}
384 
385 	return ERR_PTR(-EINVAL);
386 }
387 
388 static void *cxlctl_get_supported_features(struct cxl_features_state *cxlfs,
389 					   const struct fwctl_rpc_cxl *rpc_in,
390 					   size_t *out_len)
391 {
392 	const struct cxl_mbox_get_sup_feats_in *feat_in;
393 	struct cxl_mbox_get_sup_feats_out *feat_out;
394 	struct cxl_feat_entry *pos;
395 	size_t out_size;
396 	int requested;
397 	u32 count;
398 	u16 start;
399 	int i;
400 
401 	if (rpc_in->op_size != sizeof(*feat_in))
402 		return ERR_PTR(-EINVAL);
403 
404 	feat_in = &rpc_in->get_sup_feats_in;
405 	count = le32_to_cpu(feat_in->count);
406 	start = le16_to_cpu(feat_in->start_idx);
407 	requested = count / sizeof(*pos);
408 
409 	/*
410 	 * Make sure that the total requested number of entries is not greater
411 	 * than the total number of supported features allowed for userspace.
412 	 */
413 	if (start >= cxlfs->entries->num_features)
414 		return ERR_PTR(-EINVAL);
415 
416 	requested = min_t(int, requested, cxlfs->entries->num_features - start);
417 
418 	out_size = sizeof(struct fwctl_rpc_cxl_out) +
419 		struct_size(feat_out, ents, requested);
420 
421 	struct fwctl_rpc_cxl_out *rpc_out __free(kvfree) =
422 		kvzalloc(out_size, GFP_KERNEL);
423 	if (!rpc_out)
424 		return ERR_PTR(-ENOMEM);
425 
426 	rpc_out->size = struct_size(feat_out, ents, requested);
427 	feat_out = &rpc_out->get_sup_feats_out;
428 	feat_out->num_entries = cpu_to_le16(requested);
429 
430 	for (i = start, pos = &feat_out->ents[0];
431 	     i < cxlfs->entries->num_features; i++, pos++) {
432 		if (i - start == requested)
433 			break;
434 
435 		memcpy(pos, &cxlfs->entries->ent[i], sizeof(*pos));
436 		/*
437 		 * If the feature is exclusive, set the set_feat_size to 0 to
438 		 * indicate that the feature is not changeable.
439 		 */
440 		if (is_cxl_feature_exclusive(pos)) {
441 			u32 flags;
442 
443 			pos->set_feat_size = 0;
444 			flags = le32_to_cpu(pos->flags);
445 			flags &= ~CXL_FEATURE_F_CHANGEABLE;
446 			pos->flags = cpu_to_le32(flags);
447 		}
448 	}
449 
450 	feat_out->supported_feats = cpu_to_le16(cxlfs->entries->num_features);
451 	rpc_out->retval = CXL_MBOX_CMD_RC_SUCCESS;
452 	*out_len = out_size;
453 
454 	return no_free_ptr(rpc_out);
455 }
456 
457 static void *cxlctl_get_feature(struct cxl_features_state *cxlfs,
458 				const struct fwctl_rpc_cxl *rpc_in,
459 				size_t *out_len)
460 {
461 	struct cxl_mailbox *cxl_mbox = &cxlfs->cxlds->cxl_mbox;
462 	const struct cxl_mbox_get_feat_in *feat_in;
463 	u16 offset, count, return_code;
464 	size_t out_size = *out_len;
465 
466 	if (rpc_in->op_size != sizeof(*feat_in))
467 		return ERR_PTR(-EINVAL);
468 
469 	feat_in = &rpc_in->get_feat_in;
470 	offset = le16_to_cpu(feat_in->offset);
471 	count = le16_to_cpu(feat_in->count);
472 
473 	if (!count)
474 		return ERR_PTR(-EINVAL);
475 
476 	if (out_size < offsetof(struct fwctl_rpc_cxl_out, payload) ||
477 	    count > out_size - offsetof(struct fwctl_rpc_cxl_out, payload))
478 		return ERR_PTR(-EINVAL);
479 
480 	struct fwctl_rpc_cxl_out *rpc_out __free(kvfree) =
481 		kvzalloc(out_size, GFP_KERNEL);
482 	if (!rpc_out)
483 		return ERR_PTR(-ENOMEM);
484 
485 	out_size = cxl_get_feature(cxl_mbox, &feat_in->uuid,
486 				   feat_in->selection, rpc_out->payload,
487 				   count, offset, &return_code);
488 	*out_len = sizeof(struct fwctl_rpc_cxl_out);
489 	if (!out_size) {
490 		rpc_out->size = 0;
491 		rpc_out->retval = return_code;
492 		return no_free_ptr(rpc_out);
493 	}
494 
495 	rpc_out->size = out_size;
496 	rpc_out->retval = CXL_MBOX_CMD_RC_SUCCESS;
497 	*out_len += out_size;
498 
499 	return no_free_ptr(rpc_out);
500 }
501 
502 static void *cxlctl_set_feature(struct cxl_features_state *cxlfs,
503 				const struct fwctl_rpc_cxl *rpc_in,
504 				size_t *out_len)
505 {
506 	struct cxl_mailbox *cxl_mbox = &cxlfs->cxlds->cxl_mbox;
507 	const struct cxl_mbox_set_feat_in *feat_in;
508 	size_t out_size, data_size;
509 	u16 offset, return_code;
510 	u32 flags;
511 	int rc;
512 
513 	if (rpc_in->op_size <= sizeof(feat_in->hdr))
514 		return ERR_PTR(-EINVAL);
515 
516 	feat_in = &rpc_in->set_feat_in;
517 
518 	if (is_cxl_feature_exclusive_by_uuid(&feat_in->uuid))
519 		return ERR_PTR(-EPERM);
520 
521 	offset = le16_to_cpu(feat_in->offset);
522 	flags = le32_to_cpu(feat_in->flags);
523 	out_size = *out_len;
524 
525 	if (out_size < offsetof(struct fwctl_rpc_cxl_out, payload))
526 		return ERR_PTR(-EINVAL);
527 
528 	struct fwctl_rpc_cxl_out *rpc_out __free(kvfree) =
529 		kvzalloc(out_size, GFP_KERNEL);
530 	if (!rpc_out)
531 		return ERR_PTR(-ENOMEM);
532 
533 	rpc_out->size = 0;
534 
535 	data_size = rpc_in->op_size - sizeof(feat_in->hdr);
536 	rc = cxl_set_feature(cxl_mbox, &feat_in->uuid,
537 			     feat_in->version, feat_in->feat_data,
538 			     data_size, flags, offset, &return_code);
539 	*out_len = sizeof(*rpc_out);
540 	if (rc) {
541 		rpc_out->retval = return_code;
542 		return no_free_ptr(rpc_out);
543 	}
544 
545 	rpc_out->retval = CXL_MBOX_CMD_RC_SUCCESS;
546 
547 	return no_free_ptr(rpc_out);
548 }
549 
550 static bool cxlctl_validate_set_features(struct cxl_features_state *cxlfs,
551 					 const struct fwctl_rpc_cxl *rpc_in,
552 					 enum fwctl_rpc_scope scope)
553 {
554 	u16 effects, imm_mask, reset_mask;
555 	struct cxl_feat_entry *feat;
556 	u32 flags;
557 
558 	if (rpc_in->op_size < sizeof(uuid_t))
559 		return false;
560 
561 	feat = cxl_feature_info(cxlfs, &rpc_in->set_feat_in.uuid);
562 	if (IS_ERR(feat))
563 		return false;
564 
565 	/* Ensure that the attribute is changeable */
566 	flags = le32_to_cpu(feat->flags);
567 	if (!(flags & CXL_FEATURE_F_CHANGEABLE))
568 		return false;
569 
570 	effects = le16_to_cpu(feat->effects);
571 
572 	/*
573 	 * Reserved bits are set, rejecting since the effects is not
574 	 * comprehended by the driver.
575 	 */
576 	if (effects & CXL_CMD_EFFECTS_RESERVED) {
577 		dev_warn_once(cxlfs->cxlds->dev,
578 			      "Reserved bits set in the Feature effects field!\n");
579 		return false;
580 	}
581 
582 	/* Currently no user background command support */
583 	if (effects & CXL_CMD_BACKGROUND)
584 		return false;
585 
586 	/* Effects cause immediate change, highest security scope is needed */
587 	imm_mask = CXL_CMD_CONFIG_CHANGE_IMMEDIATE |
588 		   CXL_CMD_DATA_CHANGE_IMMEDIATE |
589 		   CXL_CMD_POLICY_CHANGE_IMMEDIATE |
590 		   CXL_CMD_LOG_CHANGE_IMMEDIATE;
591 
592 	reset_mask = CXL_CMD_CONFIG_CHANGE_COLD_RESET |
593 		     CXL_CMD_CONFIG_CHANGE_CONV_RESET |
594 		     CXL_CMD_CONFIG_CHANGE_CXL_RESET;
595 
596 	/* If no immediate or reset effect set, The hardware has a bug */
597 	if (!(effects & imm_mask) && !(effects & reset_mask))
598 		return false;
599 
600 	/*
601 	 * If the Feature setting causes immediate configuration change
602 	 * then we need the full write permission policy.
603 	 */
604 	if (effects & imm_mask && scope >= FWCTL_RPC_DEBUG_WRITE_FULL)
605 		return true;
606 
607 	/*
608 	 * If the Feature setting only causes configuration change
609 	 * after a reset, then the lesser level of write permission
610 	 * policy is ok.
611 	 */
612 	if (!(effects & imm_mask) && scope >= FWCTL_RPC_DEBUG_WRITE)
613 		return true;
614 
615 	return false;
616 }
617 
618 static bool cxlctl_validate_hw_command(struct cxl_features_state *cxlfs,
619 				       const struct fwctl_rpc_cxl *rpc_in,
620 				       enum fwctl_rpc_scope scope,
621 				       u16 opcode)
622 {
623 	struct cxl_mailbox *cxl_mbox = &cxlfs->cxlds->cxl_mbox;
624 
625 	switch (opcode) {
626 	case CXL_MBOX_OP_GET_SUPPORTED_FEATURES:
627 	case CXL_MBOX_OP_GET_FEATURE:
628 		return cxl_mbox->feat_cap >= CXL_FEATURES_RO;
629 	case CXL_MBOX_OP_SET_FEATURE:
630 		if (cxl_mbox->feat_cap < CXL_FEATURES_RW)
631 			return false;
632 		return cxlctl_validate_set_features(cxlfs, rpc_in, scope);
633 	default:
634 		return false;
635 	}
636 }
637 
638 static void *cxlctl_handle_commands(struct cxl_features_state *cxlfs,
639 				    const struct fwctl_rpc_cxl *rpc_in,
640 				    size_t *out_len, u16 opcode)
641 {
642 	switch (opcode) {
643 	case CXL_MBOX_OP_GET_SUPPORTED_FEATURES:
644 		return cxlctl_get_supported_features(cxlfs, rpc_in, out_len);
645 	case CXL_MBOX_OP_GET_FEATURE:
646 		return cxlctl_get_feature(cxlfs, rpc_in, out_len);
647 	case CXL_MBOX_OP_SET_FEATURE:
648 		return cxlctl_set_feature(cxlfs, rpc_in, out_len);
649 	default:
650 		return ERR_PTR(-EOPNOTSUPP);
651 	}
652 }
653 
654 static void *cxlctl_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
655 			   void *in, size_t in_len, size_t *out_len)
656 {
657 	struct fwctl_device *fwctl_dev = uctx->fwctl;
658 	struct cxl_memdev *cxlmd = fwctl_to_memdev(fwctl_dev);
659 	struct cxl_features_state *cxlfs = to_cxlfs(cxlmd->cxlds);
660 	const struct fwctl_rpc_cxl *rpc_in = in;
661 	u16 opcode;
662 
663 	if (in_len < sizeof(rpc_in->hdr) ||
664 	    rpc_in->op_size > in_len - sizeof(rpc_in->hdr))
665 		return ERR_PTR(-EINVAL);
666 
667 	opcode = rpc_in->opcode;
668 
669 	if (!cxlctl_validate_hw_command(cxlfs, rpc_in, scope, opcode))
670 		return ERR_PTR(-EINVAL);
671 
672 	return cxlctl_handle_commands(cxlfs, rpc_in, out_len, opcode);
673 }
674 
675 static const struct fwctl_ops cxlctl_ops = {
676 	.device_type = FWCTL_DEVICE_TYPE_CXL,
677 	.uctx_size = sizeof(struct fwctl_uctx),
678 	.open_uctx = cxlctl_open_uctx,
679 	.close_uctx = cxlctl_close_uctx,
680 	.fw_rpc = cxlctl_fw_rpc,
681 };
682 
683 DEFINE_FREE(free_fwctl_dev, struct fwctl_device *, if (_T) fwctl_put(_T))
684 
685 static void free_memdev_fwctl(void *_fwctl_dev)
686 {
687 	struct fwctl_device *fwctl_dev = _fwctl_dev;
688 
689 	fwctl_unregister(fwctl_dev);
690 	fwctl_put(fwctl_dev);
691 }
692 
693 int devm_cxl_setup_fwctl(struct device *host, struct cxl_memdev *cxlmd)
694 {
695 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
696 	struct cxl_features_state *cxlfs;
697 	int rc;
698 
699 	cxlfs = to_cxlfs(cxlds);
700 	if (!cxlfs)
701 		return -ENODEV;
702 
703 	/* No need to setup FWCTL if there are no user allowed features found */
704 	if (!cxlfs->entries->num_user_features)
705 		return -ENODEV;
706 
707 	struct fwctl_device *fwctl_dev __free(free_fwctl_dev) =
708 		_fwctl_alloc_device(&cxlmd->dev, &cxlctl_ops, sizeof(*fwctl_dev));
709 	if (!fwctl_dev)
710 		return -ENOMEM;
711 
712 	rc = fwctl_register(fwctl_dev);
713 	if (rc)
714 		return rc;
715 
716 	return devm_add_action_or_reset(host, free_memdev_fwctl,
717 					no_free_ptr(fwctl_dev));
718 }
719 EXPORT_SYMBOL_NS_GPL(devm_cxl_setup_fwctl, "CXL");
720 
721 MODULE_IMPORT_NS("FWCTL");
722