aboutsummaryrefslogtreecommitdiffstats
path: root/arch/powerpc/platforms/pseries/hotplug-memory.c
blob: 2f166136bb50af2e28e5af1f77919c3a4818c71c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
/*
 * pseries Memory Hotplug infrastructure.
 *
 * Copyright (C) 2008 Badari Pulavarty, IBM Corporation
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#define pr_fmt(fmt)	"pseries-hotplug-mem: " fmt

#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/memblock.h>
#include <linux/memory.h>
#include <linux/memory_hotplug.h>
#include <linux/slab.h>

#include <asm/firmware.h>
#include <asm/machdep.h>
#include <asm/prom.h>
#include <asm/sparsemem.h>
#include <asm/fadump.h>
#include <asm/drmem.h>
#include "pseries.h"

static bool rtas_hp_event;

unsigned long pseries_memory_block_size(void)
{
	struct device_node *np;
	unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
	struct resource r;

	np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
	if (np) {
		const __be64 *size;

		size = of_get_property(np, "ibm,lmb-size", NULL);
		if (size)
			memblock_size = be64_to_cpup(size);
		of_node_put(np);
	} else  if (machine_is(pseries)) {
		/* This fallback really only applies to pseries */
		unsigned int memzero_size = 0;

		np = of_find_node_by_path("/memory@0");
		if (np) {
			if (!of_address_to_resource(np, 0, &r))
				memzero_size = resource_size(&r);
			of_node_put(np);
		}

		if (memzero_size) {
			/* We now know the size of memory@0, use this to find
			 * the first memoryblock and get its size.
			 */
			char buf[64];

			sprintf(buf, "/memory@%x", memzero_size);
			np = of_find_node_by_path(buf);
			if (np) {
				if (!of_address_to_resource(np, 0, &r))
					memblock_size = resource_size(&r);
				of_node_put(np);
			}
		}
	}
	return memblock_size;
}

static void dlpar_free_property(struct property *prop)
{
	kfree(prop->name);
	kfree(prop->value);
	kfree(prop);
}

static struct property *dlpar_clone_property(struct property *prop,
					     u32 prop_size)
{
	struct property *new_prop;

	new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
	if (!new_prop)
		return NULL;

	new_prop->name = kstrdup(prop->name, GFP_KERNEL);
	new_prop->value = kzalloc(prop_size, GFP_KERNEL);
	if (!new_prop->name || !new_prop->value) {
		dlpar_free_property(new_prop);
		return NULL;
	}

	memcpy(new_prop->value, prop->value, prop->length);
	new_prop->length = prop_size;

	of_property_set_flag(new_prop, OF_DYNAMIC);
	return new_prop;
}

static u32 find_aa_index(struct device_node *dr_node,
			 struct property *ala_prop, const u32 *lmb_assoc)
{
	u32 *assoc_arrays;
	u32 aa_index;
	int aa_arrays, aa_array_entries, aa_array_sz;
	int i, index;

	/*
	 * The ibm,associativity-lookup-arrays property is defined to be
	 * a 32-bit value specifying the number of associativity arrays
	 * followed by a 32-bitvalue specifying the number of entries per
	 * array, followed by the associativity arrays.
	 */
	assoc_arrays = ala_prop->value;

	aa_arrays = be32_to_cpu(assoc_arrays[0]);
	aa_array_entries = be32_to_cpu(assoc_arrays[1]);
	aa_array_sz = aa_array_entries * sizeof(u32);

	aa_index = -1;
	for (i = 0; i < aa_arrays; i++) {
		index = (i * aa_array_entries) + 2;

		if (memcmp(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz))
			continue;

		aa_index = i;
		break;
	}

	if (aa_index == -1) {
		struct property *new_prop;
		u32 new_prop_size;

		new_prop_size = ala_prop->length + aa_array_sz;
		new_prop = dlpar_clone_property(ala_prop, new_prop_size);
		if (!new_prop)
			return -1;

		assoc_arrays = new_prop->value;

		/* increment the number of entries in the lookup array */
		assoc_arrays[0] = cpu_to_be32(aa_arrays + 1);

		/* copy the new associativity into the lookup array */
		index = aa_arrays * aa_array_entries + 2;
		memcpy(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz);

		of_update_property(dr_node, new_prop);

		/*
		 * The associativity lookup array index for this lmb is
		 * number of entries - 1 since we added its associativity
		 * to the end of the lookup array.
		 */
		aa_index = be32_to_cpu(assoc_arrays[0]) - 1;
	}

	return aa_index;
}

static int update_lmb_associativity_index(struct drmem_lmb *lmb)
{
	struct device_node *parent, *lmb_node, *dr_node;
	struct property *ala_prop;
	const u32 *lmb_assoc;
	u32 aa_index;

	parent = of_find_node_by_path("/");
	if (!parent)
		return -ENODEV;

	lmb_node = dlpar_configure_connector(cpu_to_be32(lmb->drc_index),
					     parent);
	of_node_put(parent);
	if (!lmb_node)
		return -EINVAL;

	lmb_assoc = of_get_property(lmb_node, "ibm,associativity", NULL);
	if (!lmb_assoc) {
		dlpar_free_cc_nodes(lmb_node);
		return -ENODEV;
	}

	dr_node = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
	if (!dr_node) {
		dlpar_free_cc_nodes(lmb_node);
		return -ENODEV;
	}

	ala_prop = of_find_property(dr_node, "ibm,associativity-lookup-arrays",
				    NULL);
	if (!ala_prop) {
		of_node_put(dr_node);
		dlpar_free_cc_nodes(lmb_node);
		return -ENODEV;
	}

	aa_index = find_aa_index(dr_node, ala_prop, lmb_assoc);

	dlpar_free_cc_nodes(lmb_node);

	if (aa_index < 0) {
		pr_err("Could not find LMB associativity\n");
		return -1;
	}

	lmb->aa_index = aa_index;
	return 0;
}

static struct memory_block *lmb_to_memblock(struct drmem_lmb *lmb)
{
	unsigned long section_nr;
	struct mem_section *mem_sect;
	struct memory_block *mem_block;

	section_nr = pfn_to_section_nr(PFN_DOWN(lmb->base_addr));
	mem_sect = __nr_to_section(section_nr);

	mem_block = find_memory_block(mem_sect);
	return mem_block;
}

static int get_lmb_range(u32 drc_index, int n_lmbs,
			 struct drmem_lmb **start_lmb,
			 struct drmem_lmb **end_lmb)
{
	struct drmem_lmb *lmb, *start, *end;
	struct drmem_lmb *last_lmb;

	start = NULL;
	for_each_drmem_lmb(lmb) {
		if (lmb->drc_index == drc_index) {
			start = lmb;
			break;
		}
	}

	if (!start)
		return -EINVAL;

	end = &start[n_lmbs - 1];

	last_lmb = &drmem_info->lmbs[drmem_info->n_lmbs - 1];
	if (end > last_lmb)
		return -EINVAL;

	*start_lmb = start;
	*end_lmb = end;
	return 0;
}

static int dlpar_change_lmb_state(struct drmem_lmb *lmb, bool online)
{
	struct memory_block *mem_block;
	int rc;

	mem_block = lmb_to_memblock(lmb);
	if (!mem_block)
		return -EINVAL;

	if (online && mem_block->dev.offline)
		rc = device_online(&mem_block->dev);
	else if (!online && !mem_block->dev.offline)
		rc = device_offline(&mem_block->dev);
	else
		rc = 0;

	put_device(&mem_block->dev);

	return rc;
}

static int dlpar_online_lmb(struct drmem_lmb *lmb)
{
	return dlpar_change_lmb_state(lmb, true);
}

#ifdef CONFIG_MEMORY_HOTREMOVE
static int dlpar_offline_lmb(struct drmem_lmb *lmb)
{
	return dlpar_change_lmb_state(lmb, false);
}

static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
{
	unsigned long block_sz, start_pfn;
	int sections_per_block;
	int i, nid;

	start_pfn = base >> PAGE_SHIFT;

	lock_device_hotplug();

	if (!pfn_valid(start_pfn))
		goto out;

	block_sz = pseries_memory_block_size();
	sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
	nid = memory_add_physaddr_to_nid(base);

	for (i = 0; i < sections_per_block; i++) {
		remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
		base += MIN_MEMORY_BLOCK_SIZE;
	}

out:
	/* Update memory regions for memory remove */
	memblock_remove(base, memblock_size);
	unlock_device_hotplug();
	return 0;
}

static int pseries_remove_mem_node(struct device_node *np)
{
	const char *type;
	const __be32 *regs;
	unsigned long base;
	unsigned int lmb_size;
	int ret = -EINVAL;

	/*
	 * Check to see if we are actually removing memory
	 */
	type = of_get_property(np, "device_type", NULL);
	if (type == NULL || strcmp(type, "memory") != 0)
		return 0;

	/*
	 * Find the base address and size of the memblock
	 */
	regs = of_get_property(np, "reg", NULL);
	if (!regs)
		return ret;

	base = be64_to_cpu(*(unsigned long *)regs);
	lmb_size = be32_to_cpu(regs[3]);

	pseries_remove_memblock(base, lmb_size);
	return 0;
}

static bool lmb_is_removable(struct drmem_lmb *lmb)
{
	int i, scns_per_block;
	int rc = 1;
	unsigned long pfn, block_sz;
	u64 phys_addr;

	if (!(lmb->flags & DRCONF_MEM_ASSIGNED))
		return false;

	block_sz = memory_block_size_bytes();
	scns_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
	phys_addr = lmb->base_addr;

#ifdef CONFIG_FA_DUMP
	/*
	 * Don't hot-remove memory that falls in fadump boot memory area
	 * and memory that is reserved for capturing old kernel memory.
	 */
	if (is_fadump_memory_area(phys_addr, block_sz))
		return false;
#endif

	for (i = 0; i < scns_per_block; i++) {
		pfn = PFN_DOWN(phys_addr);
		if (!pfn_present(pfn))
			continue;

		rc &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
		phys_addr += MIN_MEMORY_BLOCK_SIZE;
	}

	return rc ? true : false;
}

static int dlpar_add_lmb(struct drmem_lmb *);

static int dlpar_remove_lmb(struct drmem_lmb *lmb)
{
	unsigned long block_sz;
	int nid, rc;

	if (!lmb_is_removable(lmb))
		return -EINVAL;

	rc = dlpar_offline_lmb(lmb);
	if (rc)
		return rc;

	block_sz = pseries_memory_block_size();
	nid = memory_add_physaddr_to_nid(lmb->base_addr);

	remove_memory(nid, lmb->base_addr, block_sz);

	/* Update memory regions for memory remove */
	memblock_remove(lmb->base_addr, block_sz);

	invalidate_lmb_associativity_index(lmb);
	lmb->flags &= ~DRCONF_MEM_ASSIGNED;

	return 0;
}

static int dlpar_memory_remove_by_count(u32 lmbs_to_remove)
{
	struct drmem_lmb *lmb;
	int lmbs_removed = 0;
	int lmbs_available = 0;
	int rc;

	pr_info("Attempting to hot-remove %d LMB(s)\n", lmbs_to_remove);

	if (lmbs_to_remove == 0)
		return -EINVAL;

	/* Validate that there are enough LMBs to satisfy the request */
	for_each_drmem_lmb(lmb) {
		if (lmb_is_removable(lmb))
			lmbs_available++;

		if (lmbs_available == lmbs_to_remove)
			break;
	}

	if (lmbs_available < lmbs_to_remove) {
		pr_info("Not enough LMBs available (%d of %d) to satisfy request\n",
			lmbs_available, lmbs_to_remove);
		return -EINVAL;
	}

	for_each_drmem_lmb(lmb) {
		rc = dlpar_remove_lmb(lmb);
		if (rc)
			continue;

		/* Mark this lmb so we can add it later if all of the
		 * requested LMBs cannot be removed.
		 */
		drmem_mark_lmb_reserved(lmb);

		lmbs_removed++;
		if (lmbs_removed == lmbs_to_remove)
			break;
	}

	if (lmbs_removed != lmbs_to_remove) {
		pr_err("Memory hot-remove failed, adding LMB's back\n");

		for_each_drmem_lmb(lmb) {
			if (!drmem_lmb_reserved(lmb))
				continue;

			rc = dlpar_add_lmb(lmb);
			if (rc)
				pr_err("Failed to add LMB back, drc index %x\n",
				       lmb->drc_index);

			drmem_remove_lmb_reservation(lmb);
		}

		rc = -EINVAL;
	} else {
		for_each_drmem_lmb(lmb) {
			if (!drmem_lmb_reserved(lmb))
				continue;

			dlpar_release_drc(lmb->drc_index);
			pr_info("Memory at %llx was hot-removed\n",
				lmb->base_addr);

			drmem_remove_lmb_reservation(lmb);
		}
		rc = 0;
	}

	return rc;
}

static int dlpar_memory_remove_by_index(u32 drc_index)
{
	struct drmem_lmb *lmb;
	int lmb_found;
	int rc;

	pr_info("Attempting to hot-remove LMB, drc index %x\n", drc_index);

	lmb_found = 0;
	for_each_drmem_lmb(lmb) {
		if (lmb->drc_index == drc_index) {
			lmb_found = 1;
			rc = dlpar_remove_lmb(lmb);
			if (!rc)
				dlpar_release_drc(lmb->drc_index);

			break;
		}
	}

	if (!lmb_found)
		rc = -EINVAL;

	if (rc)
		pr_info("Failed to hot-remove memory at %llx\n",
			lmb->base_addr);
	else
		pr_info("Memory at %llx was hot-removed\n", lmb->base_addr);

	return rc;
}

static int dlpar_memory_readd_by_index(u32 drc_index)
{
	struct drmem_lmb *lmb;
	int lmb_found;
	int rc;

	pr_info("Attempting to update LMB, drc index %x\n", drc_index);

	lmb_found = 0;
	for_each_drmem_lmb(lmb) {
		if (lmb->drc_index == drc_index) {
			lmb_found = 1;
			rc = dlpar_remove_lmb(lmb);
			if (!rc) {
				rc = dlpar_add_lmb(lmb);
				if (rc)
					dlpar_release_drc(lmb->drc_index);
			}
			break;
		}
	}

	if (!lmb_found)
		rc = -EINVAL;

	if (rc)
		pr_info("Failed to update memory at %llx\n",
			lmb->base_addr);
	else
		pr_info("Memory at %llx was updated\n", lmb->base_addr);

	return rc;
}

static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index)
{
	struct drmem_lmb *lmb, *start_lmb, *end_lmb;
	int lmbs_available = 0;
	int rc;

	pr_info("Attempting to hot-remove %u LMB(s) at %x\n",
		lmbs_to_remove, drc_index);

	if (lmbs_to_remove == 0)
		return -EINVAL;

	rc = get_lmb_range(drc_index, lmbs_to_remove, &start_lmb, &end_lmb);
	if (rc)
		return -EINVAL;

	/* Validate that there are enough LMBs to satisfy the request */
	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
		if (lmb->flags & DRCONF_MEM_RESERVED)
			break;

		lmbs_available++;
	}

	if (lmbs_available < lmbs_to_remove)
		return -EINVAL;

	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
		if (!(lmb->flags & DRCONF_MEM_ASSIGNED))
			continue;

		rc = dlpar_remove_lmb(lmb);
		if (rc)
			break;

		drmem_mark_lmb_reserved(lmb);
	}

	if (rc) {
		pr_err("Memory indexed-count-remove failed, adding any removed LMBs\n");


		for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
			if (!drmem_lmb_reserved(lmb))
				continue;

			rc = dlpar_add_lmb(lmb);
			if (rc)
				pr_err("Failed to add LMB, drc index %x\n",
				       lmb->drc_index);

			drmem_remove_lmb_reservation(lmb);
		}
		rc = -EINVAL;
	} else {
		for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
			if (!drmem_lmb_reserved(lmb))
				continue;

			dlpar_release_drc(lmb->drc_index);
			pr_info("Memory at %llx (drc index %x) was hot-removed\n",
				lmb->base_addr, lmb->drc_index);

			drmem_remove_lmb_reservation(lmb);
		}
	}

	return rc;
}

#else
static inline int pseries_remove_memblock(unsigned long base,
					  unsigned int memblock_size)
{
	return -EOPNOTSUPP;
}
static inline int pseries_remove_mem_node(struct device_node *np)
{
	return 0;
}
static inline int dlpar_memory_remove(struct pseries_hp_errorlog *hp_elog)
{
	return -EOPNOTSUPP;
}
static int dlpar_remove_lmb(struct drmem_lmb *lmb)
{
	return -EOPNOTSUPP;
}
static int dlpar_memory_remove_by_count(u32 lmbs_to_remove)
{
	return -EOPNOTSUPP;
}
static int dlpar_memory_remove_by_index(u32 drc_index)
{
	return -EOPNOTSUPP;
}
static int dlpar_memory_readd_by_index(u32 drc_index)
{
	return -EOPNOTSUPP;
}

static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index)
{
	return -EOPNOTSUPP;
}
#endif /* CONFIG_MEMORY_HOTREMOVE */

static int dlpar_add_lmb(struct drmem_lmb *lmb)
{
	unsigned long block_sz;
	int nid, rc;

	if (lmb->flags & DRCONF_MEM_ASSIGNED)
		return -EINVAL;

	rc = update_lmb_associativity_index(lmb);
	if (rc) {
		dlpar_release_drc(lmb->drc_index);
		return rc;
	}

	block_sz = memory_block_size_bytes();

	/* Find the node id for this address */
	nid = memory_add_physaddr_to_nid(lmb->base_addr);

	/* Add the memory */
	rc = add_memory(nid, lmb->base_addr, block_sz);
	if (rc) {
		invalidate_lmb_associativity_index(lmb);
		return rc;
	}

	rc = dlpar_online_lmb(lmb);
	if (rc) {
		remove_memory(nid, lmb->base_addr, block_sz);
		invalidate_lmb_associativity_index(lmb);
	} else {
		lmb->flags |= DRCONF_MEM_ASSIGNED;
	}

	return rc;
}

static int dlpar_memory_add_by_count(u32 lmbs_to_add)
{
	struct drmem_lmb *lmb;
	int lmbs_available = 0;
	int lmbs_added = 0;
	int rc;

	pr_info("Attempting to hot-add %d LMB(s)\n", lmbs_to_add);

	if (lmbs_to_add == 0)
		return -EINVAL;

	/* Validate that there are enough LMBs to satisfy the request */
	for_each_drmem_lmb(lmb) {
		if (!(lmb->flags & DRCONF_MEM_ASSIGNED))
			lmbs_available++;

		if (lmbs_available == lmbs_to_add)
			break;
	}

	if (lmbs_available < lmbs_to_add)
		return -EINVAL;

	for_each_drmem_lmb(lmb) {
		if (lmb->flags & DRCONF_MEM_ASSIGNED)
			continue;

		rc = dlpar_acquire_drc(lmb->drc_index);
		if (rc)
			continue;

		rc = dlpar_add_lmb(lmb);
		if (rc) {
			dlpar_release_drc(lmb->drc_index);
			continue;
		}

		/* Mark this lmb so we can remove it later if all of the
		 * requested LMBs cannot be added.
		 */
		drmem_mark_lmb_reserved(lmb);

		lmbs_added++;
		if (lmbs_added == lmbs_to_add)
			break;
	}

	if (lmbs_added != lmbs_to_add) {
		pr_err("Memory hot-add failed, removing any added LMBs\n");

		for_each_drmem_lmb(lmb) {
			if (!drmem_lmb_reserved(lmb))
				continue;

			rc = dlpar_remove_lmb(lmb);
			if (rc)
				pr_err("Failed to remove LMB, drc index %x\n",
				       lmb->drc_index);
			else
				dlpar_release_drc(lmb->drc_index);

			drmem_remove_lmb_reservation(lmb);
		}
		rc = -EINVAL;
	} else {
		for_each_drmem_lmb(lmb) {
			if (!drmem_lmb_reserved(lmb))
				continue;

			pr_info("Memory at %llx (drc index %x) was hot-added\n",
				lmb->base_addr, lmb->drc_index);
			drmem_remove_lmb_reservation(lmb);
		}
		rc = 0;
	}

	return rc;
}

static int dlpar_memory_add_by_index(u32 drc_index)
{
	struct drmem_lmb *lmb;
	int rc, lmb_found;

	pr_info("Attempting to hot-add LMB, drc index %x\n", drc_index);

	lmb_found = 0;
	for_each_drmem_lmb(lmb) {
		if (lmb->drc_index == drc_index) {
			lmb_found = 1;
			rc = dlpar_acquire_drc(lmb->drc_index);
			if (!rc) {
				rc = dlpar_add_lmb(lmb);
				if (rc)
					dlpar_release_drc(lmb->drc_index);
			}

			break;
		}
	}

	if (!lmb_found)
		rc = -EINVAL;

	if (rc)
		pr_info("Failed to hot-add memory, drc index %x\n", drc_index);
	else
		pr_info("Memory at %llx (drc index %x) was hot-added\n",
			lmb->base_addr, drc_index);

	return rc;
}

static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index)
{
	struct drmem_lmb *lmb, *start_lmb, *end_lmb;
	int lmbs_available = 0;
	int rc;

	pr_info("Attempting to hot-add %u LMB(s) at index %x\n",
		lmbs_to_add, drc_index);

	if (lmbs_to_add == 0)
		return -EINVAL;

	rc = get_lmb_range(drc_index, lmbs_to_add, &start_lmb, &end_lmb);
	if (rc)
		return -EINVAL;

	/* Validate that the LMBs in this range are not reserved */
	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
		if (lmb->flags & DRCONF_MEM_RESERVED)
			break;

		lmbs_available++;
	}

	if (lmbs_available < lmbs_to_add)
		return -EINVAL;

	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
		if (lmb->flags & DRCONF_MEM_ASSIGNED)
			continue;

		rc = dlpar_acquire_drc(lmb->drc_index);
		if (rc)
			break;

		rc = dlpar_add_lmb(lmb);
		if (rc) {
			dlpar_release_drc(lmb->drc_index);
			break;
		}

		drmem_mark_lmb_reserved(lmb);
	}

	if (rc) {
		pr_err("Memory indexed-count-add failed, removing any added LMBs\n");

		for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
			if (!drmem_lmb_reserved(lmb))
				continue;

			rc = dlpar_remove_lmb(lmb);
			if (rc)
				pr_err("Failed to remove LMB, drc index %x\n",
				       lmb->drc_index);
			else
				dlpar_release_drc(lmb->drc_index);

			drmem_remove_lmb_reservation(lmb);
		}
		rc = -EINVAL;
	} else {
		for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
			if (!drmem_lmb_reserved(lmb))
				continue;

			pr_info("Memory at %llx (drc index %x) was hot-added\n",
				lmb->base_addr, lmb->drc_index);
			drmem_remove_lmb_reservation(lmb);
		}
	}

	return rc;
}

int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
{
	u32 count, drc_index;
	int rc;

	lock_device_hotplug();

	switch (hp_elog->action) {
	case PSERIES_HP_ELOG_ACTION_ADD:
		if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT) {
			count = hp_elog->_drc_u.drc_count;
			rc = dlpar_memory_add_by_count(count);
		} else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX) {
			drc_index = hp_elog->_drc_u.drc_index;
			rc = dlpar_memory_add_by_index(drc_index);
		} else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_IC) {
			count = hp_elog->_drc_u.ic.count;
			drc_index = hp_elog->_drc_u.ic.index;
			rc = dlpar_memory_add_by_ic(count, drc_index);
		} else {
			rc = -EINVAL;
		}

		break;
	case PSERIES_HP_ELOG_ACTION_REMOVE:
		if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT) {
			count = hp_elog->_drc_u.drc_count;
			rc = dlpar_memory_remove_by_count(count);
		} else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX) {
			drc_index = hp_elog->_drc_u.drc_index;
			rc = dlpar_memory_remove_by_index(drc_index);
		} else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_IC) {
			count = hp_elog->_drc_u.ic.count;
			drc_index = hp_elog->_drc_u.ic.index;
			rc = dlpar_memory_remove_by_ic(count, drc_index);
		} else {
			rc = -EINVAL;
		}

		break;
	case PSERIES_HP_ELOG_ACTION_READD:
		drc_index = hp_elog->_drc_u.drc_index;
		rc = dlpar_memory_readd_by_index(drc_index);
		break;
	default:
		pr_err("Invalid action (%d) specified\n", hp_elog->action);
		rc = -EINVAL;
		break;
	}

	if (!rc) {
		rtas_hp_event = true;
		rc = drmem_update_dt();
		rtas_hp_event = false;
	}

	unlock_device_hotplug();
	return rc;
}

static int pseries_add_mem_node(struct device_node *np)
{
	const char *type;
	const __be32 *regs;
	unsigned long base;
	unsigned int lmb_size;
	int ret = -EINVAL;

	/*
	 * Check to see if we are actually adding memory
	 */
	type = of_get_property(np, "device_type", NULL);
	if (type == NULL || strcmp(type, "memory") != 0)
		return 0;

	/*
	 * Find the base and size of the memblock
	 */
	regs = of_get_property(np, "reg", NULL);
	if (!regs)
		return ret;

	base = be64_to_cpu(*(unsigned long *)regs);
	lmb_size = be32_to_cpu(regs[3]);

	/*
	 * Update memory region to represent the memory add
	 */
	ret = memblock_add(base, lmb_size);
	return (ret < 0) ? -EINVAL : 0;
}

static int pseries_update_drconf_memory(struct of_reconfig_data *pr)
{
	struct of_drconf_cell_v1 *new_drmem, *old_drmem;
	unsigned long memblock_size;
	u32 entries;
	__be32 *p;
	int i, rc = -EINVAL;

	if (rtas_hp_event)
		return 0;

	memblock_size = pseries_memory_block_size();
	if (!memblock_size)
		return -EINVAL;

	if (!pr->old_prop)
		return 0;

	p = (__be32 *) pr->old_prop->value;
	if (!p)
		return -EINVAL;

	/* The first int of the property is the number of lmb's described
	 * by the property. This is followed by an array of of_drconf_cell
	 * entries. Get the number of entries and skip to the array of
	 * of_drconf_cell's.
	 */
	entries = be32_to_cpu(*p++);
	old_drmem = (struct of_drconf_cell_v1 *)p;

	p = (__be32 *)pr->prop->value;
	p++;
	new_drmem = (struct of_drconf_cell_v1 *)p;

	for (i = 0; i < entries; i++) {
		if ((be32_to_cpu(old_drmem[i].flags) & DRCONF_MEM_ASSIGNED) &&
		    (!(be32_to_cpu(new_drmem[i].flags) & DRCONF_MEM_ASSIGNED))) {
			rc = pseries_remove_memblock(
				be64_to_cpu(old_drmem[i].base_addr),
						     memblock_size);
			break;
		} else if ((!(be32_to_cpu(old_drmem[i].flags) &
			    DRCONF_MEM_ASSIGNED)) &&
			    (be32_to_cpu(new_drmem[i].flags) &
			    DRCONF_MEM_ASSIGNED)) {
			rc = memblock_add(be64_to_cpu(old_drmem[i].base_addr),
					  memblock_size);
			rc = (rc < 0) ? -EINVAL : 0;
			break;
		}
	}
	return rc;
}

static int pseries_memory_notifier(struct notifier_block *nb,
				   unsigned long action, void *data)
{
	struct of_reconfig_data *rd = data;
	int err = 0;

	switch (action) {
	case OF_RECONFIG_ATTACH_NODE:
		err = pseries_add_mem_node(rd->dn);
		break;
	case OF_RECONFIG_DETACH_NODE:
		err = pseries_remove_mem_node(rd->dn);
		break;
	case OF_RECONFIG_UPDATE_PROPERTY:
		if (!strcmp(rd->prop->name, "ibm,dynamic-memory"))
			err = pseries_update_drconf_memory(rd);
		break;
	}
	return notifier_from_errno(err);
}

static struct notifier_block pseries_mem_nb = {
	.notifier_call = pseries_memory_notifier,
};

static int __init pseries_memory_hotplug_init(void)
{
	if (firmware_has_feature(FW_FEATURE_LPAR))
		of_reconfig_notifier_register(&pseries_mem_nb);

	return 0;
}
machine_device_initcall(pseries, pseries_memory_hotplug_init);