1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * pseries Memory Hotplug infrastructure.
4  *
5  * Copyright (C) 2008 Badari Pulavarty, IBM Corporation
6  */
7 
8 #define pr_fmt(fmt)	"pseries-hotplug-mem: " fmt
9 
10 #include <linux/of.h>
11 #include <linux/of_address.h>
12 #include <linux/memblock.h>
13 #include <linux/memory.h>
14 #include <linux/memory_hotplug.h>
15 #include <linux/slab.h>
16 
17 #include <asm/firmware.h>
18 #include <asm/machdep.h>
19 #include <asm/prom.h>
20 #include <asm/sparsemem.h>
21 #include <asm/fadump.h>
22 #include <asm/drmem.h>
23 #include "pseries.h"
24 
25 unsigned long pseries_memory_block_size(void)
26 {
27 	struct device_node *np;
28 	u64 memblock_size = MIN_MEMORY_BLOCK_SIZE;
29 	struct resource r;
30 
31 	np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
32 	if (np) {
33 		int len;
34 		int size_cells;
35 		const __be32 *prop;
36 
37 		size_cells = of_n_size_cells(np);
38 
39 		prop = of_get_property(np, "ibm,lmb-size", &len);
40 		if (prop && len >= size_cells * sizeof(__be32))
41 			memblock_size = of_read_number(prop, size_cells);
42 		of_node_put(np);
43 
44 	} else  if (machine_is(pseries)) {
45 		/* This fallback really only applies to pseries */
46 		unsigned int memzero_size = 0;
47 
48 		np = of_find_node_by_path("/memory@0");
49 		if (np) {
50 			if (!of_address_to_resource(np, 0, &r))
51 				memzero_size = resource_size(&r);
52 			of_node_put(np);
53 		}
54 
55 		if (memzero_size) {
56 			/* We now know the size of memory@0, use this to find
57 			 * the first memoryblock and get its size.
58 			 */
59 			char buf[64];
60 
61 			sprintf(buf, "/memory@%x", memzero_size);
62 			np = of_find_node_by_path(buf);
63 			if (np) {
64 				if (!of_address_to_resource(np, 0, &r))
65 					memblock_size = resource_size(&r);
66 				of_node_put(np);
67 			}
68 		}
69 	}
70 	return memblock_size;
71 }
72 
73 static void dlpar_free_property(struct property *prop)
74 {
75 	kfree(prop->name);
76 	kfree(prop->value);
77 	kfree(prop);
78 }
79 
80 static struct property *dlpar_clone_property(struct property *prop,
81 					     u32 prop_size)
82 {
83 	struct property *new_prop;
84 
85 	new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
86 	if (!new_prop)
87 		return NULL;
88 
89 	new_prop->name = kstrdup(prop->name, GFP_KERNEL);
90 	new_prop->value = kzalloc(prop_size, GFP_KERNEL);
91 	if (!new_prop->name || !new_prop->value) {
92 		dlpar_free_property(new_prop);
93 		return NULL;
94 	}
95 
96 	memcpy(new_prop->value, prop->value, prop->length);
97 	new_prop->length = prop_size;
98 
99 	of_property_set_flag(new_prop, OF_DYNAMIC);
100 	return new_prop;
101 }
102 
103 static bool find_aa_index(struct device_node *dr_node,
104 			 struct property *ala_prop,
105 			 const u32 *lmb_assoc, u32 *aa_index)
106 {
107 	u32 *assoc_arrays, new_prop_size;
108 	struct property *new_prop;
109 	int aa_arrays, aa_array_entries, aa_array_sz;
110 	int i, index;
111 
112 	/*
113 	 * The ibm,associativity-lookup-arrays property is defined to be
114 	 * a 32-bit value specifying the number of associativity arrays
115 	 * followed by a 32-bitvalue specifying the number of entries per
116 	 * array, followed by the associativity arrays.
117 	 */
118 	assoc_arrays = ala_prop->value;
119 
120 	aa_arrays = be32_to_cpu(assoc_arrays[0]);
121 	aa_array_entries = be32_to_cpu(assoc_arrays[1]);
122 	aa_array_sz = aa_array_entries * sizeof(u32);
123 
124 	for (i = 0; i < aa_arrays; i++) {
125 		index = (i * aa_array_entries) + 2;
126 
127 		if (memcmp(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz))
128 			continue;
129 
130 		*aa_index = i;
131 		return true;
132 	}
133 
134 	new_prop_size = ala_prop->length + aa_array_sz;
135 	new_prop = dlpar_clone_property(ala_prop, new_prop_size);
136 	if (!new_prop)
137 		return false;
138 
139 	assoc_arrays = new_prop->value;
140 
141 	/* increment the number of entries in the lookup array */
142 	assoc_arrays[0] = cpu_to_be32(aa_arrays + 1);
143 
144 	/* copy the new associativity into the lookup array */
145 	index = aa_arrays * aa_array_entries + 2;
146 	memcpy(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz);
147 
148 	of_update_property(dr_node, new_prop);
149 
150 	/*
151 	 * The associativity lookup array index for this lmb is
152 	 * number of entries - 1 since we added its associativity
153 	 * to the end of the lookup array.
154 	 */
155 	*aa_index = be32_to_cpu(assoc_arrays[0]) - 1;
156 	return true;
157 }
158 
159 static int update_lmb_associativity_index(struct drmem_lmb *lmb)
160 {
161 	struct device_node *parent, *lmb_node, *dr_node;
162 	struct property *ala_prop;
163 	const u32 *lmb_assoc;
164 	u32 aa_index;
165 	bool found;
166 
167 	parent = of_find_node_by_path("/");
168 	if (!parent)
169 		return -ENODEV;
170 
171 	lmb_node = dlpar_configure_connector(cpu_to_be32(lmb->drc_index),
172 					     parent);
173 	of_node_put(parent);
174 	if (!lmb_node)
175 		return -EINVAL;
176 
177 	lmb_assoc = of_get_property(lmb_node, "ibm,associativity", NULL);
178 	if (!lmb_assoc) {
179 		dlpar_free_cc_nodes(lmb_node);
180 		return -ENODEV;
181 	}
182 
183 	dr_node = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
184 	if (!dr_node) {
185 		dlpar_free_cc_nodes(lmb_node);
186 		return -ENODEV;
187 	}
188 
189 	ala_prop = of_find_property(dr_node, "ibm,associativity-lookup-arrays",
190 				    NULL);
191 	if (!ala_prop) {
192 		of_node_put(dr_node);
193 		dlpar_free_cc_nodes(lmb_node);
194 		return -ENODEV;
195 	}
196 
197 	found = find_aa_index(dr_node, ala_prop, lmb_assoc, &aa_index);
198 
199 	of_node_put(dr_node);
200 	dlpar_free_cc_nodes(lmb_node);
201 
202 	if (!found) {
203 		pr_err("Could not find LMB associativity\n");
204 		return -1;
205 	}
206 
207 	lmb->aa_index = aa_index;
208 	return 0;
209 }
210 
211 static struct memory_block *lmb_to_memblock(struct drmem_lmb *lmb)
212 {
213 	unsigned long section_nr;
214 	struct mem_section *mem_sect;
215 	struct memory_block *mem_block;
216 
217 	section_nr = pfn_to_section_nr(PFN_DOWN(lmb->base_addr));
218 	mem_sect = __nr_to_section(section_nr);
219 
220 	mem_block = find_memory_block(mem_sect);
221 	return mem_block;
222 }
223 
224 static int get_lmb_range(u32 drc_index, int n_lmbs,
225 			 struct drmem_lmb **start_lmb,
226 			 struct drmem_lmb **end_lmb)
227 {
228 	struct drmem_lmb *lmb, *start, *end;
229 	struct drmem_lmb *limit;
230 
231 	start = NULL;
232 	for_each_drmem_lmb(lmb) {
233 		if (lmb->drc_index == drc_index) {
234 			start = lmb;
235 			break;
236 		}
237 	}
238 
239 	if (!start)
240 		return -EINVAL;
241 
242 	end = &start[n_lmbs];
243 
244 	limit = &drmem_info->lmbs[drmem_info->n_lmbs];
245 	if (end > limit)
246 		return -EINVAL;
247 
248 	*start_lmb = start;
249 	*end_lmb = end;
250 	return 0;
251 }
252 
253 static int dlpar_change_lmb_state(struct drmem_lmb *lmb, bool online)
254 {
255 	struct memory_block *mem_block;
256 	int rc;
257 
258 	mem_block = lmb_to_memblock(lmb);
259 	if (!mem_block)
260 		return -EINVAL;
261 
262 	if (online && mem_block->dev.offline)
263 		rc = device_online(&mem_block->dev);
264 	else if (!online && !mem_block->dev.offline)
265 		rc = device_offline(&mem_block->dev);
266 	else
267 		rc = 0;
268 
269 	put_device(&mem_block->dev);
270 
271 	return rc;
272 }
273 
274 static int dlpar_online_lmb(struct drmem_lmb *lmb)
275 {
276 	return dlpar_change_lmb_state(lmb, true);
277 }
278 
279 #ifdef CONFIG_MEMORY_HOTREMOVE
280 static int dlpar_offline_lmb(struct drmem_lmb *lmb)
281 {
282 	return dlpar_change_lmb_state(lmb, false);
283 }
284 
285 static int pseries_remove_memblock(unsigned long base, unsigned long memblock_size)
286 {
287 	unsigned long block_sz, start_pfn;
288 	int sections_per_block;
289 	int i, nid;
290 
291 	start_pfn = base >> PAGE_SHIFT;
292 
293 	lock_device_hotplug();
294 
295 	if (!pfn_valid(start_pfn))
296 		goto out;
297 
298 	block_sz = pseries_memory_block_size();
299 	sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
300 	nid = memory_add_physaddr_to_nid(base);
301 
302 	for (i = 0; i < sections_per_block; i++) {
303 		__remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
304 		base += MIN_MEMORY_BLOCK_SIZE;
305 	}
306 
307 out:
308 	/* Update memory regions for memory remove */
309 	memblock_remove(base, memblock_size);
310 	unlock_device_hotplug();
311 	return 0;
312 }
313 
314 static int pseries_remove_mem_node(struct device_node *np)
315 {
316 	const __be32 *prop;
317 	unsigned long base;
318 	unsigned long lmb_size;
319 	int ret = -EINVAL;
320 	int addr_cells, size_cells;
321 
322 	/*
323 	 * Check to see if we are actually removing memory
324 	 */
325 	if (!of_node_is_type(np, "memory"))
326 		return 0;
327 
328 	/*
329 	 * Find the base address and size of the memblock
330 	 */
331 	prop = of_get_property(np, "reg", NULL);
332 	if (!prop)
333 		return ret;
334 
335 	addr_cells = of_n_addr_cells(np);
336 	size_cells = of_n_size_cells(np);
337 
338 	/*
339 	 * "reg" property represents (addr,size) tuple.
340 	 */
341 	base = of_read_number(prop, addr_cells);
342 	prop += addr_cells;
343 	lmb_size = of_read_number(prop, size_cells);
344 
345 	pseries_remove_memblock(base, lmb_size);
346 	return 0;
347 }
348 
349 static bool lmb_is_removable(struct drmem_lmb *lmb)
350 {
351 	if ((lmb->flags & DRCONF_MEM_RESERVED) ||
352 		!(lmb->flags & DRCONF_MEM_ASSIGNED))
353 		return false;
354 
355 #ifdef CONFIG_FA_DUMP
356 	/*
357 	 * Don't hot-remove memory that falls in fadump boot memory area
358 	 * and memory that is reserved for capturing old kernel memory.
359 	 */
360 	if (is_fadump_memory_area(lmb->base_addr, memory_block_size_bytes()))
361 		return false;
362 #endif
363 	/* device_offline() will determine if we can actually remove this lmb */
364 	return true;
365 }
366 
367 static int dlpar_add_lmb(struct drmem_lmb *);
368 
369 static int dlpar_remove_lmb(struct drmem_lmb *lmb)
370 {
371 	struct memory_block *mem_block;
372 	unsigned long block_sz;
373 	int rc;
374 
375 	if (!lmb_is_removable(lmb))
376 		return -EINVAL;
377 
378 	mem_block = lmb_to_memblock(lmb);
379 	if (mem_block == NULL)
380 		return -EINVAL;
381 
382 	rc = dlpar_offline_lmb(lmb);
383 	if (rc) {
384 		put_device(&mem_block->dev);
385 		return rc;
386 	}
387 
388 	block_sz = pseries_memory_block_size();
389 
390 	__remove_memory(mem_block->nid, lmb->base_addr, block_sz);
391 	put_device(&mem_block->dev);
392 
393 	/* Update memory regions for memory remove */
394 	memblock_remove(lmb->base_addr, block_sz);
395 
396 	invalidate_lmb_associativity_index(lmb);
397 	lmb->flags &= ~DRCONF_MEM_ASSIGNED;
398 
399 	return 0;
400 }
401 
402 static int dlpar_memory_remove_by_count(u32 lmbs_to_remove)
403 {
404 	struct drmem_lmb *lmb;
405 	int lmbs_reserved = 0;
406 	int lmbs_available = 0;
407 	int rc;
408 
409 	pr_info("Attempting to hot-remove %d LMB(s)\n", lmbs_to_remove);
410 
411 	if (lmbs_to_remove == 0)
412 		return -EINVAL;
413 
414 	/* Validate that there are enough LMBs to satisfy the request */
415 	for_each_drmem_lmb(lmb) {
416 		if (lmb_is_removable(lmb))
417 			lmbs_available++;
418 
419 		if (lmbs_available == lmbs_to_remove)
420 			break;
421 	}
422 
423 	if (lmbs_available < lmbs_to_remove) {
424 		pr_info("Not enough LMBs available (%d of %d) to satisfy request\n",
425 			lmbs_available, lmbs_to_remove);
426 		return -EINVAL;
427 	}
428 
429 	for_each_drmem_lmb(lmb) {
430 		rc = dlpar_remove_lmb(lmb);
431 		if (rc)
432 			continue;
433 
434 		/* Mark this lmb so we can add it later if all of the
435 		 * requested LMBs cannot be removed.
436 		 */
437 		drmem_mark_lmb_reserved(lmb);
438 
439 		lmbs_reserved++;
440 		if (lmbs_reserved == lmbs_to_remove)
441 			break;
442 	}
443 
444 	if (lmbs_reserved != lmbs_to_remove) {
445 		pr_err("Memory hot-remove failed, adding LMB's back\n");
446 
447 		for_each_drmem_lmb(lmb) {
448 			if (!drmem_lmb_reserved(lmb))
449 				continue;
450 
451 			rc = dlpar_add_lmb(lmb);
452 			if (rc)
453 				pr_err("Failed to add LMB back, drc index %x\n",
454 				       lmb->drc_index);
455 
456 			drmem_remove_lmb_reservation(lmb);
457 
458 			lmbs_reserved--;
459 			if (lmbs_reserved == 0)
460 				break;
461 		}
462 
463 		rc = -EINVAL;
464 	} else {
465 		for_each_drmem_lmb(lmb) {
466 			if (!drmem_lmb_reserved(lmb))
467 				continue;
468 
469 			dlpar_release_drc(lmb->drc_index);
470 			pr_info("Memory at %llx was hot-removed\n",
471 				lmb->base_addr);
472 
473 			drmem_remove_lmb_reservation(lmb);
474 
475 			lmbs_reserved--;
476 			if (lmbs_reserved == 0)
477 				break;
478 		}
479 		rc = 0;
480 	}
481 
482 	return rc;
483 }
484 
485 static int dlpar_memory_remove_by_index(u32 drc_index)
486 {
487 	struct drmem_lmb *lmb;
488 	int lmb_found;
489 	int rc;
490 
491 	pr_debug("Attempting to hot-remove LMB, drc index %x\n", drc_index);
492 
493 	lmb_found = 0;
494 	for_each_drmem_lmb(lmb) {
495 		if (lmb->drc_index == drc_index) {
496 			lmb_found = 1;
497 			rc = dlpar_remove_lmb(lmb);
498 			if (!rc)
499 				dlpar_release_drc(lmb->drc_index);
500 
501 			break;
502 		}
503 	}
504 
505 	if (!lmb_found)
506 		rc = -EINVAL;
507 
508 	if (rc)
509 		pr_debug("Failed to hot-remove memory at %llx\n",
510 			 lmb->base_addr);
511 	else
512 		pr_debug("Memory at %llx was hot-removed\n", lmb->base_addr);
513 
514 	return rc;
515 }
516 
517 static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index)
518 {
519 	struct drmem_lmb *lmb, *start_lmb, *end_lmb;
520 	int rc;
521 
522 	pr_info("Attempting to hot-remove %u LMB(s) at %x\n",
523 		lmbs_to_remove, drc_index);
524 
525 	if (lmbs_to_remove == 0)
526 		return -EINVAL;
527 
528 	rc = get_lmb_range(drc_index, lmbs_to_remove, &start_lmb, &end_lmb);
529 	if (rc)
530 		return -EINVAL;
531 
532 	/*
533 	 * Validate that all LMBs in range are not reserved. Note that it
534 	 * is ok if they are !ASSIGNED since our goal here is to remove the
535 	 * LMB range, regardless of whether some LMBs were already removed
536 	 * by any other reason.
537 	 *
538 	 * This is a contrast to what is done in remove_by_count() where we
539 	 * check for both RESERVED and !ASSIGNED (via lmb_is_removable()),
540 	 * because we want to remove a fixed amount of LMBs in that function.
541 	 */
542 	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
543 		if (lmb->flags & DRCONF_MEM_RESERVED) {
544 			pr_err("Memory at %llx (drc index %x) is reserved\n",
545 				lmb->base_addr, lmb->drc_index);
546 			return -EINVAL;
547 		}
548 	}
549 
550 	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
551 		/*
552 		 * dlpar_remove_lmb() will error out if the LMB is already
553 		 * !ASSIGNED, but this case is a no-op for us.
554 		 */
555 		if (!(lmb->flags & DRCONF_MEM_ASSIGNED))
556 			continue;
557 
558 		rc = dlpar_remove_lmb(lmb);
559 		if (rc)
560 			break;
561 
562 		drmem_mark_lmb_reserved(lmb);
563 	}
564 
565 	if (rc) {
566 		pr_err("Memory indexed-count-remove failed, adding any removed LMBs\n");
567 
568 
569 		for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
570 			if (!drmem_lmb_reserved(lmb))
571 				continue;
572 
573 			/*
574 			 * Setting the isolation state of an UNISOLATED/CONFIGURED
575 			 * device to UNISOLATE is a no-op, but the hypervisor can
576 			 * use it as a hint that the LMB removal failed.
577 			 */
578 			dlpar_unisolate_drc(lmb->drc_index);
579 
580 			rc = dlpar_add_lmb(lmb);
581 			if (rc)
582 				pr_err("Failed to add LMB, drc index %x\n",
583 				       lmb->drc_index);
584 
585 			drmem_remove_lmb_reservation(lmb);
586 		}
587 		rc = -EINVAL;
588 	} else {
589 		for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
590 			if (!drmem_lmb_reserved(lmb))
591 				continue;
592 
593 			dlpar_release_drc(lmb->drc_index);
594 			pr_info("Memory at %llx (drc index %x) was hot-removed\n",
595 				lmb->base_addr, lmb->drc_index);
596 
597 			drmem_remove_lmb_reservation(lmb);
598 		}
599 	}
600 
601 	return rc;
602 }
603 
604 #else
605 static inline int pseries_remove_memblock(unsigned long base,
606 					  unsigned long memblock_size)
607 {
608 	return -EOPNOTSUPP;
609 }
610 static inline int pseries_remove_mem_node(struct device_node *np)
611 {
612 	return 0;
613 }
614 static int dlpar_remove_lmb(struct drmem_lmb *lmb)
615 {
616 	return -EOPNOTSUPP;
617 }
618 static int dlpar_memory_remove_by_count(u32 lmbs_to_remove)
619 {
620 	return -EOPNOTSUPP;
621 }
622 static int dlpar_memory_remove_by_index(u32 drc_index)
623 {
624 	return -EOPNOTSUPP;
625 }
626 
627 static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index)
628 {
629 	return -EOPNOTSUPP;
630 }
631 #endif /* CONFIG_MEMORY_HOTREMOVE */
632 
633 static int dlpar_add_lmb(struct drmem_lmb *lmb)
634 {
635 	unsigned long block_sz;
636 	int nid, rc;
637 
638 	if (lmb->flags & DRCONF_MEM_ASSIGNED)
639 		return -EINVAL;
640 
641 	rc = update_lmb_associativity_index(lmb);
642 	if (rc) {
643 		dlpar_release_drc(lmb->drc_index);
644 		return rc;
645 	}
646 
647 	block_sz = memory_block_size_bytes();
648 
649 	/* Find the node id for this LMB.  Fake one if necessary. */
650 	nid = of_drconf_to_nid_single(lmb);
651 	if (nid < 0 || !node_possible(nid))
652 		nid = first_online_node;
653 
654 	/* Add the memory */
655 	rc = __add_memory(nid, lmb->base_addr, block_sz, MHP_NONE);
656 	if (rc) {
657 		invalidate_lmb_associativity_index(lmb);
658 		return rc;
659 	}
660 
661 	rc = dlpar_online_lmb(lmb);
662 	if (rc) {
663 		__remove_memory(nid, lmb->base_addr, block_sz);
664 		invalidate_lmb_associativity_index(lmb);
665 	} else {
666 		lmb->flags |= DRCONF_MEM_ASSIGNED;
667 	}
668 
669 	return rc;
670 }
671 
672 static int dlpar_memory_add_by_count(u32 lmbs_to_add)
673 {
674 	struct drmem_lmb *lmb;
675 	int lmbs_available = 0;
676 	int lmbs_added = 0;
677 	int rc;
678 
679 	pr_info("Attempting to hot-add %d LMB(s)\n", lmbs_to_add);
680 
681 	if (lmbs_to_add == 0)
682 		return -EINVAL;
683 
684 	/* Validate that there are enough LMBs to satisfy the request */
685 	for_each_drmem_lmb(lmb) {
686 		if (!(lmb->flags & DRCONF_MEM_ASSIGNED))
687 			lmbs_available++;
688 
689 		if (lmbs_available == lmbs_to_add)
690 			break;
691 	}
692 
693 	if (lmbs_available < lmbs_to_add)
694 		return -EINVAL;
695 
696 	for_each_drmem_lmb(lmb) {
697 		if (lmb->flags & DRCONF_MEM_ASSIGNED)
698 			continue;
699 
700 		rc = dlpar_acquire_drc(lmb->drc_index);
701 		if (rc)
702 			continue;
703 
704 		rc = dlpar_add_lmb(lmb);
705 		if (rc) {
706 			dlpar_release_drc(lmb->drc_index);
707 			continue;
708 		}
709 
710 		/* Mark this lmb so we can remove it later if all of the
711 		 * requested LMBs cannot be added.
712 		 */
713 		drmem_mark_lmb_reserved(lmb);
714 
715 		lmbs_added++;
716 		if (lmbs_added == lmbs_to_add)
717 			break;
718 	}
719 
720 	if (lmbs_added != lmbs_to_add) {
721 		pr_err("Memory hot-add failed, removing any added LMBs\n");
722 
723 		for_each_drmem_lmb(lmb) {
724 			if (!drmem_lmb_reserved(lmb))
725 				continue;
726 
727 			rc = dlpar_remove_lmb(lmb);
728 			if (rc)
729 				pr_err("Failed to remove LMB, drc index %x\n",
730 				       lmb->drc_index);
731 			else
732 				dlpar_release_drc(lmb->drc_index);
733 
734 			drmem_remove_lmb_reservation(lmb);
735 		}
736 		rc = -EINVAL;
737 	} else {
738 		for_each_drmem_lmb(lmb) {
739 			if (!drmem_lmb_reserved(lmb))
740 				continue;
741 
742 			pr_debug("Memory at %llx (drc index %x) was hot-added\n",
743 				 lmb->base_addr, lmb->drc_index);
744 			drmem_remove_lmb_reservation(lmb);
745 		}
746 		rc = 0;
747 	}
748 
749 	return rc;
750 }
751 
752 static int dlpar_memory_add_by_index(u32 drc_index)
753 {
754 	struct drmem_lmb *lmb;
755 	int rc, lmb_found;
756 
757 	pr_info("Attempting to hot-add LMB, drc index %x\n", drc_index);
758 
759 	lmb_found = 0;
760 	for_each_drmem_lmb(lmb) {
761 		if (lmb->drc_index == drc_index) {
762 			lmb_found = 1;
763 			rc = dlpar_acquire_drc(lmb->drc_index);
764 			if (!rc) {
765 				rc = dlpar_add_lmb(lmb);
766 				if (rc)
767 					dlpar_release_drc(lmb->drc_index);
768 			}
769 
770 			break;
771 		}
772 	}
773 
774 	if (!lmb_found)
775 		rc = -EINVAL;
776 
777 	if (rc)
778 		pr_info("Failed to hot-add memory, drc index %x\n", drc_index);
779 	else
780 		pr_info("Memory at %llx (drc index %x) was hot-added\n",
781 			lmb->base_addr, drc_index);
782 
783 	return rc;
784 }
785 
786 static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index)
787 {
788 	struct drmem_lmb *lmb, *start_lmb, *end_lmb;
789 	int lmbs_available = 0;
790 	int rc;
791 
792 	pr_info("Attempting to hot-add %u LMB(s) at index %x\n",
793 		lmbs_to_add, drc_index);
794 
795 	if (lmbs_to_add == 0)
796 		return -EINVAL;
797 
798 	rc = get_lmb_range(drc_index, lmbs_to_add, &start_lmb, &end_lmb);
799 	if (rc)
800 		return -EINVAL;
801 
802 	/* Validate that the LMBs in this range are not reserved */
803 	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
804 		if (lmb->flags & DRCONF_MEM_RESERVED)
805 			break;
806 
807 		lmbs_available++;
808 	}
809 
810 	if (lmbs_available < lmbs_to_add)
811 		return -EINVAL;
812 
813 	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
814 		if (lmb->flags & DRCONF_MEM_ASSIGNED)
815 			continue;
816 
817 		rc = dlpar_acquire_drc(lmb->drc_index);
818 		if (rc)
819 			break;
820 
821 		rc = dlpar_add_lmb(lmb);
822 		if (rc) {
823 			dlpar_release_drc(lmb->drc_index);
824 			break;
825 		}
826 
827 		drmem_mark_lmb_reserved(lmb);
828 	}
829 
830 	if (rc) {
831 		pr_err("Memory indexed-count-add failed, removing any added LMBs\n");
832 
833 		for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
834 			if (!drmem_lmb_reserved(lmb))
835 				continue;
836 
837 			rc = dlpar_remove_lmb(lmb);
838 			if (rc)
839 				pr_err("Failed to remove LMB, drc index %x\n",
840 				       lmb->drc_index);
841 			else
842 				dlpar_release_drc(lmb->drc_index);
843 
844 			drmem_remove_lmb_reservation(lmb);
845 		}
846 		rc = -EINVAL;
847 	} else {
848 		for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
849 			if (!drmem_lmb_reserved(lmb))
850 				continue;
851 
852 			pr_info("Memory at %llx (drc index %x) was hot-added\n",
853 				lmb->base_addr, lmb->drc_index);
854 			drmem_remove_lmb_reservation(lmb);
855 		}
856 	}
857 
858 	return rc;
859 }
860 
861 int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
862 {
863 	u32 count, drc_index;
864 	int rc;
865 
866 	lock_device_hotplug();
867 
868 	switch (hp_elog->action) {
869 	case PSERIES_HP_ELOG_ACTION_ADD:
870 		switch (hp_elog->id_type) {
871 		case PSERIES_HP_ELOG_ID_DRC_COUNT:
872 			count = hp_elog->_drc_u.drc_count;
873 			rc = dlpar_memory_add_by_count(count);
874 			break;
875 		case PSERIES_HP_ELOG_ID_DRC_INDEX:
876 			drc_index = hp_elog->_drc_u.drc_index;
877 			rc = dlpar_memory_add_by_index(drc_index);
878 			break;
879 		case PSERIES_HP_ELOG_ID_DRC_IC:
880 			count = hp_elog->_drc_u.ic.count;
881 			drc_index = hp_elog->_drc_u.ic.index;
882 			rc = dlpar_memory_add_by_ic(count, drc_index);
883 			break;
884 		default:
885 			rc = -EINVAL;
886 			break;
887 		}
888 
889 		break;
890 	case PSERIES_HP_ELOG_ACTION_REMOVE:
891 		switch (hp_elog->id_type) {
892 		case PSERIES_HP_ELOG_ID_DRC_COUNT:
893 			count = hp_elog->_drc_u.drc_count;
894 			rc = dlpar_memory_remove_by_count(count);
895 			break;
896 		case PSERIES_HP_ELOG_ID_DRC_INDEX:
897 			drc_index = hp_elog->_drc_u.drc_index;
898 			rc = dlpar_memory_remove_by_index(drc_index);
899 			break;
900 		case PSERIES_HP_ELOG_ID_DRC_IC:
901 			count = hp_elog->_drc_u.ic.count;
902 			drc_index = hp_elog->_drc_u.ic.index;
903 			rc = dlpar_memory_remove_by_ic(count, drc_index);
904 			break;
905 		default:
906 			rc = -EINVAL;
907 			break;
908 		}
909 
910 		break;
911 	default:
912 		pr_err("Invalid action (%d) specified\n", hp_elog->action);
913 		rc = -EINVAL;
914 		break;
915 	}
916 
917 	if (!rc)
918 		rc = drmem_update_dt();
919 
920 	unlock_device_hotplug();
921 	return rc;
922 }
923 
924 static int pseries_add_mem_node(struct device_node *np)
925 {
926 	const __be32 *prop;
927 	unsigned long base;
928 	unsigned long lmb_size;
929 	int ret = -EINVAL;
930 	int addr_cells, size_cells;
931 
932 	/*
933 	 * Check to see if we are actually adding memory
934 	 */
935 	if (!of_node_is_type(np, "memory"))
936 		return 0;
937 
938 	/*
939 	 * Find the base and size of the memblock
940 	 */
941 	prop = of_get_property(np, "reg", NULL);
942 	if (!prop)
943 		return ret;
944 
945 	addr_cells = of_n_addr_cells(np);
946 	size_cells = of_n_size_cells(np);
947 	/*
948 	 * "reg" property represents (addr,size) tuple.
949 	 */
950 	base = of_read_number(prop, addr_cells);
951 	prop += addr_cells;
952 	lmb_size = of_read_number(prop, size_cells);
953 
954 	/*
955 	 * Update memory region to represent the memory add
956 	 */
957 	ret = memblock_add(base, lmb_size);
958 	return (ret < 0) ? -EINVAL : 0;
959 }
960 
961 static int pseries_memory_notifier(struct notifier_block *nb,
962 				   unsigned long action, void *data)
963 {
964 	struct of_reconfig_data *rd = data;
965 	int err = 0;
966 
967 	switch (action) {
968 	case OF_RECONFIG_ATTACH_NODE:
969 		err = pseries_add_mem_node(rd->dn);
970 		break;
971 	case OF_RECONFIG_DETACH_NODE:
972 		err = pseries_remove_mem_node(rd->dn);
973 		break;
974 	}
975 	return notifier_from_errno(err);
976 }
977 
978 static struct notifier_block pseries_mem_nb = {
979 	.notifier_call = pseries_memory_notifier,
980 };
981 
982 static int __init pseries_memory_hotplug_init(void)
983 {
984 	if (firmware_has_feature(FW_FEATURE_LPAR))
985 		of_reconfig_notifier_register(&pseries_mem_nb);
986 
987 	return 0;
988 }
989 machine_device_initcall(pseries, pseries_memory_hotplug_init);
990