xref: /openbmc/linux/drivers/cxl/core/hdm.c (revision 97ee19ff491479822eade8a869d49f9ddcd71e75)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright(c) 2022 Intel Corporation. All rights reserved. */
3 #include <linux/seq_file.h>
4 #include <linux/device.h>
5 #include <linux/delay.h>
6 
7 #include "cxlmem.h"
8 #include "core.h"
9 
10 /**
11  * DOC: cxl core hdm
12  *
13  * Compute Express Link Host Managed Device Memory, starting with the
14  * CXL 2.0 specification, is managed by an array of HDM Decoder register
15  * instances per CXL port and per CXL endpoint. Define common helpers
16  * for enumerating these registers and capabilities.
17  */
18 
19 DECLARE_RWSEM(cxl_dpa_rwsem);
20 
21 static int add_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
22 			   int *target_map)
23 {
24 	int rc;
25 
26 	rc = cxl_decoder_add_locked(cxld, target_map);
27 	if (rc) {
28 		put_device(&cxld->dev);
29 		dev_err(&port->dev, "Failed to add decoder\n");
30 		return rc;
31 	}
32 
33 	rc = cxl_decoder_autoremove(&port->dev, cxld);
34 	if (rc)
35 		return rc;
36 
37 	dev_dbg(&cxld->dev, "Added to port %s\n", dev_name(&port->dev));
38 
39 	return 0;
40 }
41 
42 /*
43  * Per the CXL specification (8.2.5.12 CXL HDM Decoder Capability Structure)
44  * single ported host-bridges need not publish a decoder capability when a
45  * passthrough decode can be assumed, i.e. all transactions that the uport sees
46  * are claimed and passed to the single dport. Disable the range until the first
47  * CXL region is enumerated / activated.
48  */
49 int devm_cxl_add_passthrough_decoder(struct cxl_port *port)
50 {
51 	struct cxl_switch_decoder *cxlsd;
52 	struct cxl_dport *dport = NULL;
53 	int single_port_map[1];
54 	unsigned long index;
55 
56 	cxlsd = cxl_switch_decoder_alloc(port, 1);
57 	if (IS_ERR(cxlsd))
58 		return PTR_ERR(cxlsd);
59 
60 	device_lock_assert(&port->dev);
61 
62 	xa_for_each(&port->dports, index, dport)
63 		break;
64 	single_port_map[0] = dport->port_id;
65 
66 	return add_hdm_decoder(port, &cxlsd->cxld, single_port_map);
67 }
68 EXPORT_SYMBOL_NS_GPL(devm_cxl_add_passthrough_decoder, CXL);
69 
70 static void parse_hdm_decoder_caps(struct cxl_hdm *cxlhdm)
71 {
72 	u32 hdm_cap;
73 
74 	hdm_cap = readl(cxlhdm->regs.hdm_decoder + CXL_HDM_DECODER_CAP_OFFSET);
75 	cxlhdm->decoder_count = cxl_hdm_decoder_count(hdm_cap);
76 	cxlhdm->target_count =
77 		FIELD_GET(CXL_HDM_DECODER_TARGET_COUNT_MASK, hdm_cap);
78 	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_11_8, hdm_cap))
79 		cxlhdm->interleave_mask |= GENMASK(11, 8);
80 	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_14_12, hdm_cap))
81 		cxlhdm->interleave_mask |= GENMASK(14, 12);
82 }
83 
84 static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
85 				struct cxl_component_regs *regs)
86 {
87 	struct cxl_register_map map = {
88 		.host = &port->dev,
89 		.resource = port->component_reg_phys,
90 		.base = crb,
91 		.max_size = CXL_COMPONENT_REG_BLOCK_SIZE,
92 	};
93 
94 	cxl_probe_component_regs(&port->dev, crb, &map.component_map);
95 	if (!map.component_map.hdm_decoder.valid) {
96 		dev_dbg(&port->dev, "HDM decoder registers not implemented\n");
97 		/* unique error code to indicate no HDM decoder capability */
98 		return -ENODEV;
99 	}
100 
101 	return cxl_map_component_regs(&map, regs, BIT(CXL_CM_CAP_CAP_ID_HDM));
102 }
103 
104 static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
105 {
106 	struct cxl_hdm *cxlhdm;
107 	void __iomem *hdm;
108 	u32 ctrl;
109 	int i;
110 
111 	if (!info)
112 		return false;
113 
114 	cxlhdm = dev_get_drvdata(&info->port->dev);
115 	hdm = cxlhdm->regs.hdm_decoder;
116 
117 	if (!hdm)
118 		return true;
119 
120 	/*
121 	 * If HDM decoders are present and the driver is in control of
122 	 * Mem_Enable skip DVSEC based emulation
123 	 */
124 	if (!info->mem_enabled)
125 		return false;
126 
127 	/*
128 	 * If any decoders are committed already, there should not be any
129 	 * emulated DVSEC decoders.
130 	 */
131 	for (i = 0; i < cxlhdm->decoder_count; i++) {
132 		ctrl = readl(hdm + CXL_HDM_DECODER0_CTRL_OFFSET(i));
133 		dev_dbg(&info->port->dev,
134 			"decoder%d.%d: committed: %ld base: %#x_%.8x size: %#x_%.8x\n",
135 			info->port->id, i,
136 			FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl),
137 			readl(hdm + CXL_HDM_DECODER0_BASE_HIGH_OFFSET(i)),
138 			readl(hdm + CXL_HDM_DECODER0_BASE_LOW_OFFSET(i)),
139 			readl(hdm + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(i)),
140 			readl(hdm + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(i)));
141 		if (FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl))
142 			return false;
143 	}
144 
145 	return true;
146 }
147 
148 /**
149  * devm_cxl_setup_hdm - map HDM decoder component registers
150  * @port: cxl_port to map
151  * @info: cached DVSEC range register info
152  */
153 struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port,
154 				   struct cxl_endpoint_dvsec_info *info)
155 {
156 	struct device *dev = &port->dev;
157 	struct cxl_hdm *cxlhdm;
158 	void __iomem *crb;
159 	int rc;
160 
161 	cxlhdm = devm_kzalloc(dev, sizeof(*cxlhdm), GFP_KERNEL);
162 	if (!cxlhdm)
163 		return ERR_PTR(-ENOMEM);
164 	cxlhdm->port = port;
165 	dev_set_drvdata(dev, cxlhdm);
166 
167 	crb = ioremap(port->component_reg_phys, CXL_COMPONENT_REG_BLOCK_SIZE);
168 	if (!crb && info && info->mem_enabled) {
169 		cxlhdm->decoder_count = info->ranges;
170 		return cxlhdm;
171 	} else if (!crb) {
172 		dev_err(dev, "No component registers mapped\n");
173 		return ERR_PTR(-ENXIO);
174 	}
175 
176 	rc = map_hdm_decoder_regs(port, crb, &cxlhdm->regs);
177 	iounmap(crb);
178 	if (rc)
179 		return ERR_PTR(rc);
180 
181 	parse_hdm_decoder_caps(cxlhdm);
182 	if (cxlhdm->decoder_count == 0) {
183 		dev_err(dev, "Spec violation. Caps invalid\n");
184 		return ERR_PTR(-ENXIO);
185 	}
186 
187 	/*
188 	 * Now that the hdm capability is parsed, decide if range
189 	 * register emulation is needed and fixup cxlhdm accordingly.
190 	 */
191 	if (should_emulate_decoders(info)) {
192 		dev_dbg(dev, "Fallback map %d range register%s\n", info->ranges,
193 			info->ranges > 1 ? "s" : "");
194 		cxlhdm->decoder_count = info->ranges;
195 	}
196 
197 	return cxlhdm;
198 }
199 EXPORT_SYMBOL_NS_GPL(devm_cxl_setup_hdm, CXL);
200 
201 static void __cxl_dpa_debug(struct seq_file *file, struct resource *r, int depth)
202 {
203 	unsigned long long start = r->start, end = r->end;
204 
205 	seq_printf(file, "%*s%08llx-%08llx : %s\n", depth * 2, "", start, end,
206 		   r->name);
207 }
208 
209 void cxl_dpa_debug(struct seq_file *file, struct cxl_dev_state *cxlds)
210 {
211 	struct resource *p1, *p2;
212 
213 	down_read(&cxl_dpa_rwsem);
214 	for (p1 = cxlds->dpa_res.child; p1; p1 = p1->sibling) {
215 		__cxl_dpa_debug(file, p1, 0);
216 		for (p2 = p1->child; p2; p2 = p2->sibling)
217 			__cxl_dpa_debug(file, p2, 1);
218 	}
219 	up_read(&cxl_dpa_rwsem);
220 }
221 EXPORT_SYMBOL_NS_GPL(cxl_dpa_debug, CXL);
222 
223 /*
224  * Must be called in a context that synchronizes against this decoder's
225  * port ->remove() callback (like an endpoint decoder sysfs attribute)
226  */
227 static void __cxl_dpa_release(struct cxl_endpoint_decoder *cxled)
228 {
229 	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
230 	struct cxl_port *port = cxled_to_port(cxled);
231 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
232 	struct resource *res = cxled->dpa_res;
233 	resource_size_t skip_start;
234 
235 	lockdep_assert_held_write(&cxl_dpa_rwsem);
236 
237 	/* save @skip_start, before @res is released */
238 	skip_start = res->start - cxled->skip;
239 	__release_region(&cxlds->dpa_res, res->start, resource_size(res));
240 	if (cxled->skip)
241 		__release_region(&cxlds->dpa_res, skip_start, cxled->skip);
242 	cxled->skip = 0;
243 	cxled->dpa_res = NULL;
244 	put_device(&cxled->cxld.dev);
245 	port->hdm_end--;
246 }
247 
248 static void cxl_dpa_release(void *cxled)
249 {
250 	down_write(&cxl_dpa_rwsem);
251 	__cxl_dpa_release(cxled);
252 	up_write(&cxl_dpa_rwsem);
253 }
254 
255 /*
256  * Must be called from context that will not race port device
257  * unregistration, like decoder sysfs attribute methods
258  */
259 static void devm_cxl_dpa_release(struct cxl_endpoint_decoder *cxled)
260 {
261 	struct cxl_port *port = cxled_to_port(cxled);
262 
263 	lockdep_assert_held_write(&cxl_dpa_rwsem);
264 	devm_remove_action(&port->dev, cxl_dpa_release, cxled);
265 	__cxl_dpa_release(cxled);
266 }
267 
268 static int __cxl_dpa_reserve(struct cxl_endpoint_decoder *cxled,
269 			     resource_size_t base, resource_size_t len,
270 			     resource_size_t skipped)
271 {
272 	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
273 	struct cxl_port *port = cxled_to_port(cxled);
274 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
275 	struct device *dev = &port->dev;
276 	struct resource *res;
277 
278 	lockdep_assert_held_write(&cxl_dpa_rwsem);
279 
280 	if (!len) {
281 		dev_warn(dev, "decoder%d.%d: empty reservation attempted\n",
282 			 port->id, cxled->cxld.id);
283 		return -EINVAL;
284 	}
285 
286 	if (cxled->dpa_res) {
287 		dev_dbg(dev, "decoder%d.%d: existing allocation %pr assigned\n",
288 			port->id, cxled->cxld.id, cxled->dpa_res);
289 		return -EBUSY;
290 	}
291 
292 	if (port->hdm_end + 1 != cxled->cxld.id) {
293 		/*
294 		 * Assumes alloc and commit order is always in hardware instance
295 		 * order per expectations from 8.2.5.12.20 Committing Decoder
296 		 * Programming that enforce decoder[m] committed before
297 		 * decoder[m+1] commit start.
298 		 */
299 		dev_dbg(dev, "decoder%d.%d: expected decoder%d.%d\n", port->id,
300 			cxled->cxld.id, port->id, port->hdm_end + 1);
301 		return -EBUSY;
302 	}
303 
304 	if (skipped) {
305 		res = __request_region(&cxlds->dpa_res, base - skipped, skipped,
306 				       dev_name(&cxled->cxld.dev), 0);
307 		if (!res) {
308 			dev_dbg(dev,
309 				"decoder%d.%d: failed to reserve skipped space\n",
310 				port->id, cxled->cxld.id);
311 			return -EBUSY;
312 		}
313 	}
314 	res = __request_region(&cxlds->dpa_res, base, len,
315 			       dev_name(&cxled->cxld.dev), 0);
316 	if (!res) {
317 		dev_dbg(dev, "decoder%d.%d: failed to reserve allocation\n",
318 			port->id, cxled->cxld.id);
319 		if (skipped)
320 			__release_region(&cxlds->dpa_res, base - skipped,
321 					 skipped);
322 		return -EBUSY;
323 	}
324 	cxled->dpa_res = res;
325 	cxled->skip = skipped;
326 
327 	if (resource_contains(&cxlds->pmem_res, res))
328 		cxled->mode = CXL_DECODER_PMEM;
329 	else if (resource_contains(&cxlds->ram_res, res))
330 		cxled->mode = CXL_DECODER_RAM;
331 	else {
332 		dev_dbg(dev, "decoder%d.%d: %pr mixed\n", port->id,
333 			cxled->cxld.id, cxled->dpa_res);
334 		cxled->mode = CXL_DECODER_MIXED;
335 	}
336 
337 	port->hdm_end++;
338 	get_device(&cxled->cxld.dev);
339 	return 0;
340 }
341 
342 int devm_cxl_dpa_reserve(struct cxl_endpoint_decoder *cxled,
343 				resource_size_t base, resource_size_t len,
344 				resource_size_t skipped)
345 {
346 	struct cxl_port *port = cxled_to_port(cxled);
347 	int rc;
348 
349 	down_write(&cxl_dpa_rwsem);
350 	rc = __cxl_dpa_reserve(cxled, base, len, skipped);
351 	up_write(&cxl_dpa_rwsem);
352 
353 	if (rc)
354 		return rc;
355 
356 	return devm_add_action_or_reset(&port->dev, cxl_dpa_release, cxled);
357 }
358 EXPORT_SYMBOL_NS_GPL(devm_cxl_dpa_reserve, CXL);
359 
360 resource_size_t cxl_dpa_size(struct cxl_endpoint_decoder *cxled)
361 {
362 	resource_size_t size = 0;
363 
364 	down_read(&cxl_dpa_rwsem);
365 	if (cxled->dpa_res)
366 		size = resource_size(cxled->dpa_res);
367 	up_read(&cxl_dpa_rwsem);
368 
369 	return size;
370 }
371 
372 resource_size_t cxl_dpa_resource_start(struct cxl_endpoint_decoder *cxled)
373 {
374 	resource_size_t base = -1;
375 
376 	lockdep_assert_held(&cxl_dpa_rwsem);
377 	if (cxled->dpa_res)
378 		base = cxled->dpa_res->start;
379 
380 	return base;
381 }
382 
383 int cxl_dpa_free(struct cxl_endpoint_decoder *cxled)
384 {
385 	struct cxl_port *port = cxled_to_port(cxled);
386 	struct device *dev = &cxled->cxld.dev;
387 	int rc;
388 
389 	down_write(&cxl_dpa_rwsem);
390 	if (!cxled->dpa_res) {
391 		rc = 0;
392 		goto out;
393 	}
394 	if (cxled->cxld.region) {
395 		dev_dbg(dev, "decoder assigned to: %s\n",
396 			dev_name(&cxled->cxld.region->dev));
397 		rc = -EBUSY;
398 		goto out;
399 	}
400 	if (cxled->cxld.flags & CXL_DECODER_F_ENABLE) {
401 		dev_dbg(dev, "decoder enabled\n");
402 		rc = -EBUSY;
403 		goto out;
404 	}
405 	if (cxled->cxld.id != port->hdm_end) {
406 		dev_dbg(dev, "expected decoder%d.%d\n", port->id,
407 			port->hdm_end);
408 		rc = -EBUSY;
409 		goto out;
410 	}
411 	devm_cxl_dpa_release(cxled);
412 	rc = 0;
413 out:
414 	up_write(&cxl_dpa_rwsem);
415 	return rc;
416 }
417 
418 int cxl_dpa_set_mode(struct cxl_endpoint_decoder *cxled,
419 		     enum cxl_decoder_mode mode)
420 {
421 	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
422 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
423 	struct device *dev = &cxled->cxld.dev;
424 	int rc;
425 
426 	switch (mode) {
427 	case CXL_DECODER_RAM:
428 	case CXL_DECODER_PMEM:
429 		break;
430 	default:
431 		dev_dbg(dev, "unsupported mode: %d\n", mode);
432 		return -EINVAL;
433 	}
434 
435 	down_write(&cxl_dpa_rwsem);
436 	if (cxled->cxld.flags & CXL_DECODER_F_ENABLE) {
437 		rc = -EBUSY;
438 		goto out;
439 	}
440 
441 	/*
442 	 * Only allow modes that are supported by the current partition
443 	 * configuration
444 	 */
445 	if (mode == CXL_DECODER_PMEM && !resource_size(&cxlds->pmem_res)) {
446 		dev_dbg(dev, "no available pmem capacity\n");
447 		rc = -ENXIO;
448 		goto out;
449 	}
450 	if (mode == CXL_DECODER_RAM && !resource_size(&cxlds->ram_res)) {
451 		dev_dbg(dev, "no available ram capacity\n");
452 		rc = -ENXIO;
453 		goto out;
454 	}
455 
456 	cxled->mode = mode;
457 	rc = 0;
458 out:
459 	up_write(&cxl_dpa_rwsem);
460 
461 	return rc;
462 }
463 
464 int cxl_dpa_alloc(struct cxl_endpoint_decoder *cxled, unsigned long long size)
465 {
466 	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
467 	resource_size_t free_ram_start, free_pmem_start;
468 	struct cxl_port *port = cxled_to_port(cxled);
469 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
470 	struct device *dev = &cxled->cxld.dev;
471 	resource_size_t start, avail, skip;
472 	struct resource *p, *last;
473 	int rc;
474 
475 	down_write(&cxl_dpa_rwsem);
476 	if (cxled->cxld.region) {
477 		dev_dbg(dev, "decoder attached to %s\n",
478 			dev_name(&cxled->cxld.region->dev));
479 		rc = -EBUSY;
480 		goto out;
481 	}
482 
483 	if (cxled->cxld.flags & CXL_DECODER_F_ENABLE) {
484 		dev_dbg(dev, "decoder enabled\n");
485 		rc = -EBUSY;
486 		goto out;
487 	}
488 
489 	for (p = cxlds->ram_res.child, last = NULL; p; p = p->sibling)
490 		last = p;
491 	if (last)
492 		free_ram_start = last->end + 1;
493 	else
494 		free_ram_start = cxlds->ram_res.start;
495 
496 	for (p = cxlds->pmem_res.child, last = NULL; p; p = p->sibling)
497 		last = p;
498 	if (last)
499 		free_pmem_start = last->end + 1;
500 	else
501 		free_pmem_start = cxlds->pmem_res.start;
502 
503 	if (cxled->mode == CXL_DECODER_RAM) {
504 		start = free_ram_start;
505 		avail = cxlds->ram_res.end - start + 1;
506 		skip = 0;
507 	} else if (cxled->mode == CXL_DECODER_PMEM) {
508 		resource_size_t skip_start, skip_end;
509 
510 		start = free_pmem_start;
511 		avail = cxlds->pmem_res.end - start + 1;
512 		skip_start = free_ram_start;
513 
514 		/*
515 		 * If some pmem is already allocated, then that allocation
516 		 * already handled the skip.
517 		 */
518 		if (cxlds->pmem_res.child &&
519 		    skip_start == cxlds->pmem_res.child->start)
520 			skip_end = skip_start - 1;
521 		else
522 			skip_end = start - 1;
523 		skip = skip_end - skip_start + 1;
524 	} else {
525 		dev_dbg(dev, "mode not set\n");
526 		rc = -EINVAL;
527 		goto out;
528 	}
529 
530 	if (size > avail) {
531 		dev_dbg(dev, "%pa exceeds available %s capacity: %pa\n", &size,
532 			cxled->mode == CXL_DECODER_RAM ? "ram" : "pmem",
533 			&avail);
534 		rc = -ENOSPC;
535 		goto out;
536 	}
537 
538 	rc = __cxl_dpa_reserve(cxled, start, size, skip);
539 out:
540 	up_write(&cxl_dpa_rwsem);
541 
542 	if (rc)
543 		return rc;
544 
545 	return devm_add_action_or_reset(&port->dev, cxl_dpa_release, cxled);
546 }
547 
548 static void cxld_set_interleave(struct cxl_decoder *cxld, u32 *ctrl)
549 {
550 	u16 eig;
551 	u8 eiw;
552 
553 	/*
554 	 * Input validation ensures these warns never fire, but otherwise
555 	 * suppress unititalized variable usage warnings.
556 	 */
557 	if (WARN_ONCE(ways_to_eiw(cxld->interleave_ways, &eiw),
558 		      "invalid interleave_ways: %d\n", cxld->interleave_ways))
559 		return;
560 	if (WARN_ONCE(granularity_to_eig(cxld->interleave_granularity, &eig),
561 		      "invalid interleave_granularity: %d\n",
562 		      cxld->interleave_granularity))
563 		return;
564 
565 	u32p_replace_bits(ctrl, eig, CXL_HDM_DECODER0_CTRL_IG_MASK);
566 	u32p_replace_bits(ctrl, eiw, CXL_HDM_DECODER0_CTRL_IW_MASK);
567 	*ctrl |= CXL_HDM_DECODER0_CTRL_COMMIT;
568 }
569 
570 static void cxld_set_type(struct cxl_decoder *cxld, u32 *ctrl)
571 {
572 	u32p_replace_bits(ctrl,
573 			  !!(cxld->target_type == CXL_DECODER_HOSTONLYMEM),
574 			  CXL_HDM_DECODER0_CTRL_HOSTONLY);
575 }
576 
577 static void cxlsd_set_targets(struct cxl_switch_decoder *cxlsd, u64 *tgt)
578 {
579 	struct cxl_dport **t = &cxlsd->target[0];
580 	int ways = cxlsd->cxld.interleave_ways;
581 
582 	*tgt = FIELD_PREP(GENMASK(7, 0), t[0]->port_id);
583 	if (ways > 1)
584 		*tgt |= FIELD_PREP(GENMASK(15, 8), t[1]->port_id);
585 	if (ways > 2)
586 		*tgt |= FIELD_PREP(GENMASK(23, 16), t[2]->port_id);
587 	if (ways > 3)
588 		*tgt |= FIELD_PREP(GENMASK(31, 24), t[3]->port_id);
589 	if (ways > 4)
590 		*tgt |= FIELD_PREP(GENMASK_ULL(39, 32), t[4]->port_id);
591 	if (ways > 5)
592 		*tgt |= FIELD_PREP(GENMASK_ULL(47, 40), t[5]->port_id);
593 	if (ways > 6)
594 		*tgt |= FIELD_PREP(GENMASK_ULL(55, 48), t[6]->port_id);
595 	if (ways > 7)
596 		*tgt |= FIELD_PREP(GENMASK_ULL(63, 56), t[7]->port_id);
597 }
598 
599 /*
600  * Per CXL 2.0 8.2.5.12.20 Committing Decoder Programming, hardware must set
601  * committed or error within 10ms, but just be generous with 20ms to account for
602  * clock skew and other marginal behavior
603  */
604 #define COMMIT_TIMEOUT_MS 20
605 static int cxld_await_commit(void __iomem *hdm, int id)
606 {
607 	u32 ctrl;
608 	int i;
609 
610 	for (i = 0; i < COMMIT_TIMEOUT_MS; i++) {
611 		ctrl = readl(hdm + CXL_HDM_DECODER0_CTRL_OFFSET(id));
612 		if (FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMIT_ERROR, ctrl)) {
613 			ctrl &= ~CXL_HDM_DECODER0_CTRL_COMMIT;
614 			writel(ctrl, hdm + CXL_HDM_DECODER0_CTRL_OFFSET(id));
615 			return -EIO;
616 		}
617 		if (FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl))
618 			return 0;
619 		fsleep(1000);
620 	}
621 
622 	return -ETIMEDOUT;
623 }
624 
625 static int cxl_decoder_commit(struct cxl_decoder *cxld)
626 {
627 	struct cxl_port *port = to_cxl_port(cxld->dev.parent);
628 	struct cxl_hdm *cxlhdm = dev_get_drvdata(&port->dev);
629 	void __iomem *hdm = cxlhdm->regs.hdm_decoder;
630 	int id = cxld->id, rc;
631 	u64 base, size;
632 	u32 ctrl;
633 
634 	if (cxld->flags & CXL_DECODER_F_ENABLE)
635 		return 0;
636 
637 	if (port->commit_end + 1 != id) {
638 		dev_dbg(&port->dev,
639 			"%s: out of order commit, expected decoder%d.%d\n",
640 			dev_name(&cxld->dev), port->id, port->commit_end + 1);
641 		return -EBUSY;
642 	}
643 
644 	/*
645 	 * For endpoint decoders hosted on CXL memory devices that
646 	 * support the sanitize operation, make sure sanitize is not in-flight.
647 	 */
648 	if (is_endpoint_decoder(&cxld->dev)) {
649 		struct cxl_endpoint_decoder *cxled =
650 			to_cxl_endpoint_decoder(&cxld->dev);
651 		struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
652 		struct cxl_memdev_state *mds =
653 			to_cxl_memdev_state(cxlmd->cxlds);
654 
655 		if (mds && mds->security.sanitize_active) {
656 			dev_dbg(&cxlmd->dev,
657 				"attempted to commit %s during sanitize\n",
658 				dev_name(&cxld->dev));
659 			return -EBUSY;
660 		}
661 	}
662 
663 	down_read(&cxl_dpa_rwsem);
664 	/* common decoder settings */
665 	ctrl = readl(hdm + CXL_HDM_DECODER0_CTRL_OFFSET(cxld->id));
666 	cxld_set_interleave(cxld, &ctrl);
667 	cxld_set_type(cxld, &ctrl);
668 	base = cxld->hpa_range.start;
669 	size = range_len(&cxld->hpa_range);
670 
671 	writel(upper_32_bits(base), hdm + CXL_HDM_DECODER0_BASE_HIGH_OFFSET(id));
672 	writel(lower_32_bits(base), hdm + CXL_HDM_DECODER0_BASE_LOW_OFFSET(id));
673 	writel(upper_32_bits(size), hdm + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(id));
674 	writel(lower_32_bits(size), hdm + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(id));
675 
676 	if (is_switch_decoder(&cxld->dev)) {
677 		struct cxl_switch_decoder *cxlsd =
678 			to_cxl_switch_decoder(&cxld->dev);
679 		void __iomem *tl_hi = hdm + CXL_HDM_DECODER0_TL_HIGH(id);
680 		void __iomem *tl_lo = hdm + CXL_HDM_DECODER0_TL_LOW(id);
681 		u64 targets;
682 
683 		cxlsd_set_targets(cxlsd, &targets);
684 		writel(upper_32_bits(targets), tl_hi);
685 		writel(lower_32_bits(targets), tl_lo);
686 	} else {
687 		struct cxl_endpoint_decoder *cxled =
688 			to_cxl_endpoint_decoder(&cxld->dev);
689 		void __iomem *sk_hi = hdm + CXL_HDM_DECODER0_SKIP_HIGH(id);
690 		void __iomem *sk_lo = hdm + CXL_HDM_DECODER0_SKIP_LOW(id);
691 
692 		writel(upper_32_bits(cxled->skip), sk_hi);
693 		writel(lower_32_bits(cxled->skip), sk_lo);
694 	}
695 
696 	writel(ctrl, hdm + CXL_HDM_DECODER0_CTRL_OFFSET(id));
697 	up_read(&cxl_dpa_rwsem);
698 
699 	port->commit_end++;
700 	rc = cxld_await_commit(hdm, cxld->id);
701 	if (rc) {
702 		dev_dbg(&port->dev, "%s: error %d committing decoder\n",
703 			dev_name(&cxld->dev), rc);
704 		cxld->reset(cxld);
705 		return rc;
706 	}
707 	cxld->flags |= CXL_DECODER_F_ENABLE;
708 
709 	return 0;
710 }
711 
712 static int cxl_decoder_reset(struct cxl_decoder *cxld)
713 {
714 	struct cxl_port *port = to_cxl_port(cxld->dev.parent);
715 	struct cxl_hdm *cxlhdm = dev_get_drvdata(&port->dev);
716 	void __iomem *hdm = cxlhdm->regs.hdm_decoder;
717 	int id = cxld->id;
718 	u32 ctrl;
719 
720 	if ((cxld->flags & CXL_DECODER_F_ENABLE) == 0)
721 		return 0;
722 
723 	if (port->commit_end != id) {
724 		dev_dbg(&port->dev,
725 			"%s: out of order reset, expected decoder%d.%d\n",
726 			dev_name(&cxld->dev), port->id, port->commit_end);
727 		return -EBUSY;
728 	}
729 
730 	down_read(&cxl_dpa_rwsem);
731 	ctrl = readl(hdm + CXL_HDM_DECODER0_CTRL_OFFSET(id));
732 	ctrl &= ~CXL_HDM_DECODER0_CTRL_COMMIT;
733 	writel(ctrl, hdm + CXL_HDM_DECODER0_CTRL_OFFSET(id));
734 
735 	writel(0, hdm + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(id));
736 	writel(0, hdm + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(id));
737 	writel(0, hdm + CXL_HDM_DECODER0_BASE_HIGH_OFFSET(id));
738 	writel(0, hdm + CXL_HDM_DECODER0_BASE_LOW_OFFSET(id));
739 	up_read(&cxl_dpa_rwsem);
740 
741 	port->commit_end--;
742 	cxld->flags &= ~CXL_DECODER_F_ENABLE;
743 
744 	/* Userspace is now responsible for reconfiguring this decoder */
745 	if (is_endpoint_decoder(&cxld->dev)) {
746 		struct cxl_endpoint_decoder *cxled;
747 
748 		cxled = to_cxl_endpoint_decoder(&cxld->dev);
749 		cxled->state = CXL_DECODER_STATE_MANUAL;
750 	}
751 
752 	return 0;
753 }
754 
755 static int cxl_setup_hdm_decoder_from_dvsec(
756 	struct cxl_port *port, struct cxl_decoder *cxld, u64 *dpa_base,
757 	int which, struct cxl_endpoint_dvsec_info *info)
758 {
759 	struct cxl_endpoint_decoder *cxled;
760 	u64 len;
761 	int rc;
762 
763 	if (!is_cxl_endpoint(port))
764 		return -EOPNOTSUPP;
765 
766 	cxled = to_cxl_endpoint_decoder(&cxld->dev);
767 	len = range_len(&info->dvsec_range[which]);
768 	if (!len)
769 		return -ENOENT;
770 
771 	cxld->target_type = CXL_DECODER_HOSTONLYMEM;
772 	cxld->commit = NULL;
773 	cxld->reset = NULL;
774 	cxld->hpa_range = info->dvsec_range[which];
775 
776 	/*
777 	 * Set the emulated decoder as locked pending additional support to
778 	 * change the range registers at run time.
779 	 */
780 	cxld->flags |= CXL_DECODER_F_ENABLE | CXL_DECODER_F_LOCK;
781 	port->commit_end = cxld->id;
782 
783 	rc = devm_cxl_dpa_reserve(cxled, *dpa_base, len, 0);
784 	if (rc) {
785 		dev_err(&port->dev,
786 			"decoder%d.%d: Failed to reserve DPA range %#llx - %#llx\n (%d)",
787 			port->id, cxld->id, *dpa_base, *dpa_base + len - 1, rc);
788 		return rc;
789 	}
790 	*dpa_base += len;
791 	cxled->state = CXL_DECODER_STATE_AUTO;
792 
793 	return 0;
794 }
795 
796 static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
797 			    int *target_map, void __iomem *hdm, int which,
798 			    u64 *dpa_base, struct cxl_endpoint_dvsec_info *info)
799 {
800 	struct cxl_endpoint_decoder *cxled = NULL;
801 	u64 size, base, skip, dpa_size, lo, hi;
802 	bool committed;
803 	u32 remainder;
804 	int i, rc;
805 	u32 ctrl;
806 	union {
807 		u64 value;
808 		unsigned char target_id[8];
809 	} target_list;
810 
811 	if (should_emulate_decoders(info))
812 		return cxl_setup_hdm_decoder_from_dvsec(port, cxld, dpa_base,
813 							which, info);
814 
815 	ctrl = readl(hdm + CXL_HDM_DECODER0_CTRL_OFFSET(which));
816 	lo = readl(hdm + CXL_HDM_DECODER0_BASE_LOW_OFFSET(which));
817 	hi = readl(hdm + CXL_HDM_DECODER0_BASE_HIGH_OFFSET(which));
818 	base = (hi << 32) + lo;
819 	lo = readl(hdm + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(which));
820 	hi = readl(hdm + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(which));
821 	size = (hi << 32) + lo;
822 	committed = !!(ctrl & CXL_HDM_DECODER0_CTRL_COMMITTED);
823 	cxld->commit = cxl_decoder_commit;
824 	cxld->reset = cxl_decoder_reset;
825 
826 	if (!committed)
827 		size = 0;
828 	if (base == U64_MAX || size == U64_MAX) {
829 		dev_warn(&port->dev, "decoder%d.%d: Invalid resource range\n",
830 			 port->id, cxld->id);
831 		return -ENXIO;
832 	}
833 
834 	if (info)
835 		cxled = to_cxl_endpoint_decoder(&cxld->dev);
836 	cxld->hpa_range = (struct range) {
837 		.start = base,
838 		.end = base + size - 1,
839 	};
840 
841 	/* decoders are enabled if committed */
842 	if (committed) {
843 		cxld->flags |= CXL_DECODER_F_ENABLE;
844 		if (ctrl & CXL_HDM_DECODER0_CTRL_LOCK)
845 			cxld->flags |= CXL_DECODER_F_LOCK;
846 		if (FIELD_GET(CXL_HDM_DECODER0_CTRL_HOSTONLY, ctrl))
847 			cxld->target_type = CXL_DECODER_HOSTONLYMEM;
848 		else
849 			cxld->target_type = CXL_DECODER_DEVMEM;
850 		if (cxld->id != port->commit_end + 1) {
851 			dev_warn(&port->dev,
852 				 "decoder%d.%d: Committed out of order\n",
853 				 port->id, cxld->id);
854 			return -ENXIO;
855 		}
856 
857 		if (size == 0) {
858 			dev_warn(&port->dev,
859 				 "decoder%d.%d: Committed with zero size\n",
860 				 port->id, cxld->id);
861 			return -ENXIO;
862 		}
863 		port->commit_end = cxld->id;
864 	} else {
865 		if (cxled) {
866 			struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
867 			struct cxl_dev_state *cxlds = cxlmd->cxlds;
868 
869 			/*
870 			 * Default by devtype until a device arrives that needs
871 			 * more precision.
872 			 */
873 			if (cxlds->type == CXL_DEVTYPE_CLASSMEM)
874 				cxld->target_type = CXL_DECODER_HOSTONLYMEM;
875 			else
876 				cxld->target_type = CXL_DECODER_DEVMEM;
877 		} else {
878 			/* To be overridden by region type at commit time */
879 			cxld->target_type = CXL_DECODER_HOSTONLYMEM;
880 		}
881 
882 		if (!FIELD_GET(CXL_HDM_DECODER0_CTRL_HOSTONLY, ctrl) &&
883 		    cxld->target_type == CXL_DECODER_HOSTONLYMEM) {
884 			ctrl |= CXL_HDM_DECODER0_CTRL_HOSTONLY;
885 			writel(ctrl, hdm + CXL_HDM_DECODER0_CTRL_OFFSET(which));
886 		}
887 	}
888 	rc = eiw_to_ways(FIELD_GET(CXL_HDM_DECODER0_CTRL_IW_MASK, ctrl),
889 			  &cxld->interleave_ways);
890 	if (rc) {
891 		dev_warn(&port->dev,
892 			 "decoder%d.%d: Invalid interleave ways (ctrl: %#x)\n",
893 			 port->id, cxld->id, ctrl);
894 		return rc;
895 	}
896 	rc = eig_to_granularity(FIELD_GET(CXL_HDM_DECODER0_CTRL_IG_MASK, ctrl),
897 				 &cxld->interleave_granularity);
898 	if (rc)
899 		return rc;
900 
901 	dev_dbg(&port->dev, "decoder%d.%d: range: %#llx-%#llx iw: %d ig: %d\n",
902 		port->id, cxld->id, cxld->hpa_range.start, cxld->hpa_range.end,
903 		cxld->interleave_ways, cxld->interleave_granularity);
904 
905 	if (!cxled) {
906 		lo = readl(hdm + CXL_HDM_DECODER0_TL_LOW(which));
907 		hi = readl(hdm + CXL_HDM_DECODER0_TL_HIGH(which));
908 		target_list.value = (hi << 32) + lo;
909 		for (i = 0; i < cxld->interleave_ways; i++)
910 			target_map[i] = target_list.target_id[i];
911 
912 		return 0;
913 	}
914 
915 	if (!committed)
916 		return 0;
917 
918 	dpa_size = div_u64_rem(size, cxld->interleave_ways, &remainder);
919 	if (remainder) {
920 		dev_err(&port->dev,
921 			"decoder%d.%d: invalid committed configuration size: %#llx ways: %d\n",
922 			port->id, cxld->id, size, cxld->interleave_ways);
923 		return -ENXIO;
924 	}
925 	lo = readl(hdm + CXL_HDM_DECODER0_SKIP_LOW(which));
926 	hi = readl(hdm + CXL_HDM_DECODER0_SKIP_HIGH(which));
927 	skip = (hi << 32) + lo;
928 	rc = devm_cxl_dpa_reserve(cxled, *dpa_base + skip, dpa_size, skip);
929 	if (rc) {
930 		dev_err(&port->dev,
931 			"decoder%d.%d: Failed to reserve DPA range %#llx - %#llx\n (%d)",
932 			port->id, cxld->id, *dpa_base,
933 			*dpa_base + dpa_size + skip - 1, rc);
934 		return rc;
935 	}
936 	*dpa_base += dpa_size + skip;
937 
938 	cxled->state = CXL_DECODER_STATE_AUTO;
939 
940 	return 0;
941 }
942 
943 static void cxl_settle_decoders(struct cxl_hdm *cxlhdm)
944 {
945 	void __iomem *hdm = cxlhdm->regs.hdm_decoder;
946 	int committed, i;
947 	u32 ctrl;
948 
949 	if (!hdm)
950 		return;
951 
952 	/*
953 	 * Since the register resource was recently claimed via request_region()
954 	 * be careful about trusting the "not-committed" status until the commit
955 	 * timeout has elapsed.  The commit timeout is 10ms (CXL 2.0
956 	 * 8.2.5.12.20), but double it to be tolerant of any clock skew between
957 	 * host and target.
958 	 */
959 	for (i = 0, committed = 0; i < cxlhdm->decoder_count; i++) {
960 		ctrl = readl(hdm + CXL_HDM_DECODER0_CTRL_OFFSET(i));
961 		if (ctrl & CXL_HDM_DECODER0_CTRL_COMMITTED)
962 			committed++;
963 	}
964 
965 	/* ensure that future checks of committed can be trusted */
966 	if (committed != cxlhdm->decoder_count)
967 		msleep(20);
968 }
969 
970 /**
971  * devm_cxl_enumerate_decoders - add decoder objects per HDM register set
972  * @cxlhdm: Structure to populate with HDM capabilities
973  * @info: cached DVSEC range register info
974  */
975 int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm,
976 				struct cxl_endpoint_dvsec_info *info)
977 {
978 	void __iomem *hdm = cxlhdm->regs.hdm_decoder;
979 	struct cxl_port *port = cxlhdm->port;
980 	int i;
981 	u64 dpa_base = 0;
982 
983 	cxl_settle_decoders(cxlhdm);
984 
985 	for (i = 0; i < cxlhdm->decoder_count; i++) {
986 		int target_map[CXL_DECODER_MAX_INTERLEAVE] = { 0 };
987 		int rc, target_count = cxlhdm->target_count;
988 		struct cxl_decoder *cxld;
989 
990 		if (is_cxl_endpoint(port)) {
991 			struct cxl_endpoint_decoder *cxled;
992 
993 			cxled = cxl_endpoint_decoder_alloc(port);
994 			if (IS_ERR(cxled)) {
995 				dev_warn(&port->dev,
996 					 "Failed to allocate decoder%d.%d\n",
997 					 port->id, i);
998 				return PTR_ERR(cxled);
999 			}
1000 			cxld = &cxled->cxld;
1001 		} else {
1002 			struct cxl_switch_decoder *cxlsd;
1003 
1004 			cxlsd = cxl_switch_decoder_alloc(port, target_count);
1005 			if (IS_ERR(cxlsd)) {
1006 				dev_warn(&port->dev,
1007 					 "Failed to allocate decoder%d.%d\n",
1008 					 port->id, i);
1009 				return PTR_ERR(cxlsd);
1010 			}
1011 			cxld = &cxlsd->cxld;
1012 		}
1013 
1014 		rc = init_hdm_decoder(port, cxld, target_map, hdm, i,
1015 				      &dpa_base, info);
1016 		if (rc) {
1017 			dev_warn(&port->dev,
1018 				 "Failed to initialize decoder%d.%d\n",
1019 				 port->id, i);
1020 			put_device(&cxld->dev);
1021 			return rc;
1022 		}
1023 		rc = add_hdm_decoder(port, cxld, target_map);
1024 		if (rc) {
1025 			dev_warn(&port->dev,
1026 				 "Failed to add decoder%d.%d\n", port->id, i);
1027 			return rc;
1028 		}
1029 	}
1030 
1031 	return 0;
1032 }
1033 EXPORT_SYMBOL_NS_GPL(devm_cxl_enumerate_decoders, CXL);
1034