summaryrefslogtreecommitdiff
path: root/drivers/crypto/nx/nx-842.c
blob: 6c4c000671c50d88885bb39618c5ae9e4ceabe42 (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
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
/*
 * Driver for IBM Power 842 compression accelerator
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Copyright (C) IBM Corporation, 2012
 *
 * Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
 *          Seth Jennings <sjenning@linux.vnet.ibm.com>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/nx842.h>
#include <linux/of.h>
#include <linux/slab.h>

#include <asm/page.h>
#include <asm/vio.h>

#include "nx_csbcpb.h" /* struct nx_csbcpb */

#define MODULE_NAME "nx-compress"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Robert Jennings <rcj@linux.vnet.ibm.com>");
MODULE_DESCRIPTION("842 H/W Compression driver for IBM Power processors");

#define SHIFT_4K 12
#define SHIFT_64K 16
#define SIZE_4K (1UL << SHIFT_4K)
#define SIZE_64K (1UL << SHIFT_64K)

/* IO buffer must be 128 byte aligned */
#define IO_BUFFER_ALIGN 128

struct nx842_header {
	int blocks_nr; /* number of compressed blocks */
	int offset; /* offset of the first block (from beginning of header) */
	int sizes[0]; /* size of compressed blocks */
};

static inline int nx842_header_size(const struct nx842_header *hdr)
{
	return sizeof(struct nx842_header) +
			hdr->blocks_nr * sizeof(hdr->sizes[0]);
}

/* Macros for fields within nx_csbcpb */
/* Check the valid bit within the csbcpb valid field */
#define NX842_CSBCBP_VALID_CHK(x) (x & BIT_MASK(7))

/* CE macros operate on the completion_extension field bits in the csbcpb.
 * CE0 0=full completion, 1=partial completion
 * CE1 0=CE0 indicates completion, 1=termination (output may be modified)
 * CE2 0=processed_bytes is source bytes, 1=processed_bytes is target bytes */
#define NX842_CSBCPB_CE0(x)	(x & BIT_MASK(7))
#define NX842_CSBCPB_CE1(x)	(x & BIT_MASK(6))
#define NX842_CSBCPB_CE2(x)	(x & BIT_MASK(5))

/* The NX unit accepts data only on 4K page boundaries */
#define NX842_HW_PAGE_SHIFT	SHIFT_4K
#define NX842_HW_PAGE_SIZE	(ASM_CONST(1) << NX842_HW_PAGE_SHIFT)
#define NX842_HW_PAGE_MASK	(~(NX842_HW_PAGE_SIZE-1))

enum nx842_status {
	UNAVAILABLE,
	AVAILABLE
};

struct ibm_nx842_counters {
	atomic64_t comp_complete;
	atomic64_t comp_failed;
	atomic64_t decomp_complete;
	atomic64_t decomp_failed;
	atomic64_t swdecomp;
	atomic64_t comp_times[32];
	atomic64_t decomp_times[32];
};

static struct nx842_devdata {
	struct vio_dev *vdev;
	struct device *dev;
	struct ibm_nx842_counters *counters;
	unsigned int max_sg_len;
	unsigned int max_sync_size;
	unsigned int max_sync_sg;
	enum nx842_status status;
} __rcu *devdata;
static DEFINE_SPINLOCK(devdata_mutex);

#define NX842_COUNTER_INC(_x) \
static inline void nx842_inc_##_x( \
	const struct nx842_devdata *dev) { \
	if (dev) \
		atomic64_inc(&dev->counters->_x); \
}
NX842_COUNTER_INC(comp_complete);
NX842_COUNTER_INC(comp_failed);
NX842_COUNTER_INC(decomp_complete);
NX842_COUNTER_INC(decomp_failed);
NX842_COUNTER_INC(swdecomp);

#define NX842_HIST_SLOTS 16

static void ibm_nx842_incr_hist(atomic64_t *times, unsigned int time)
{
	int bucket = fls(time);

	if (bucket)
		bucket = min((NX842_HIST_SLOTS - 1), bucket - 1);

	atomic64_inc(&times[bucket]);
}

/* NX unit operation flags */
#define NX842_OP_COMPRESS	0x0
#define NX842_OP_CRC		0x1
#define NX842_OP_DECOMPRESS	0x2
#define NX842_OP_COMPRESS_CRC   (NX842_OP_COMPRESS | NX842_OP_CRC)
#define NX842_OP_DECOMPRESS_CRC (NX842_OP_DECOMPRESS | NX842_OP_CRC)
#define NX842_OP_ASYNC		(1<<23)
#define NX842_OP_NOTIFY		(1<<22)
#define NX842_OP_NOTIFY_INT(x)	((x & 0xff)<<8)

static unsigned long nx842_get_desired_dma(struct vio_dev *viodev)
{
	/* No use of DMA mappings within the driver. */
	return 0;
}

struct nx842_slentry {
	unsigned long ptr; /* Real address (use __pa()) */
	unsigned long len;
};

/* pHyp scatterlist entry */
struct nx842_scatterlist {
	int entry_nr; /* number of slentries */
	struct nx842_slentry *entries; /* ptr to array of slentries */
};

/* Does not include sizeof(entry_nr) in the size */
static inline unsigned long nx842_get_scatterlist_size(
				struct nx842_scatterlist *sl)
{
	return sl->entry_nr * sizeof(struct nx842_slentry);
}

static int nx842_build_scatterlist(unsigned long buf, int len,
			struct nx842_scatterlist *sl)
{
	unsigned long nextpage;
	struct nx842_slentry *entry;

	sl->entry_nr = 0;

	entry = sl->entries;
	while (len) {
		entry->ptr = __pa(buf);
		nextpage = ALIGN(buf + 1, NX842_HW_PAGE_SIZE);
		if (nextpage < buf + len) {
			/* we aren't at the end yet */
			if (IS_ALIGNED(buf, NX842_HW_PAGE_SIZE))
				/* we are in the middle (or beginning) */
				entry->len = NX842_HW_PAGE_SIZE;
			else
				/* we are at the beginning */
				entry->len = nextpage - buf;
		} else {
			/* at the end */
			entry->len = len;
		}

		len -= entry->len;
		buf += entry->len;
		sl->entry_nr++;
		entry++;
	}

	return 0;
}

/*
 * Working memory for software decompression
 */
struct sw842_fifo {
	union {
		char f8[256][8];
		char f4[512][4];
	};
	char f2[256][2];
	unsigned char f84_full;
	unsigned char f2_full;
	unsigned char f8_count;
	unsigned char f2_count;
	unsigned int f4_count;
};

/*
 * Working memory for crypto API
 */
struct nx842_workmem {
	char bounce[PAGE_SIZE]; /* bounce buffer for decompression input */
	union {
		/* hardware working memory */
		struct {
			/* scatterlist */
			char slin[SIZE_4K];
			char slout[SIZE_4K];
			/* coprocessor status/parameter block */
			struct nx_csbcpb csbcpb;
		};
		/* software working memory */
		struct sw842_fifo swfifo; /* software decompression fifo */
	};
};

int nx842_get_workmem_size(void)
{
	return sizeof(struct nx842_workmem) + NX842_HW_PAGE_SIZE;
}
EXPORT_SYMBOL_GPL(nx842_get_workmem_size);

int nx842_get_workmem_size_aligned(void)
{
	return sizeof(struct nx842_workmem);
}
EXPORT_SYMBOL_GPL(nx842_get_workmem_size_aligned);

static int nx842_validate_result(struct device *dev,
	struct cop_status_block *csb)
{
	/* The csb must be valid after returning from vio_h_cop_sync */
	if (!NX842_CSBCBP_VALID_CHK(csb->valid)) {
		dev_err(dev, "%s: cspcbp not valid upon completion.\n",
				__func__);
		dev_dbg(dev, "valid:0x%02x cs:0x%02x cc:0x%02x ce:0x%02x\n",
				csb->valid,
				csb->crb_seq_number,
				csb->completion_code,
				csb->completion_extension);
		dev_dbg(dev, "processed_bytes:%d address:0x%016lx\n",
				csb->processed_byte_count,
				(unsigned long)csb->address);
		return -EIO;
	}

	/* Check return values from the hardware in the CSB */
	switch (csb->completion_code) {
	case 0:	/* Completed without error */
		break;
	case 64: /* Target bytes > Source bytes during compression */
	case 13: /* Output buffer too small */
		dev_dbg(dev, "%s: Compression output larger than input\n",
					__func__);
		return -ENOSPC;
	case 66: /* Input data contains an illegal template field */
	case 67: /* Template indicates data past the end of the input stream */
		dev_dbg(dev, "%s: Bad data for decompression (code:%d)\n",
					__func__, csb->completion_code);
		return -EINVAL;
	default:
		dev_dbg(dev, "%s: Unspecified error (code:%d)\n",
					__func__, csb->completion_code);
		return -EIO;
	}

	/* Hardware sanity check */
	if (!NX842_CSBCPB_CE2(csb->completion_extension)) {
		dev_err(dev, "%s: No error returned by hardware, but "
				"data returned is unusable, contact support.\n"
				"(Additional info: csbcbp->processed bytes "
				"does not specify processed bytes for the "
				"target buffer.)\n", __func__);
		return -EIO;
	}

	return 0;
}

/**
 * nx842_compress - Compress data using the 842 algorithm
 *
 * Compression provide by the NX842 coprocessor on IBM Power systems.
 * The input buffer is compressed and the result is stored in the
 * provided output buffer.
 *
 * Upon return from this function @outlen contains the length of the
 * compressed data.  If there is an error then @outlen will be 0 and an
 * error will be specified by the return code from this function.
 *
 * @in: Pointer to input buffer, must be page aligned
 * @inlen: Length of input buffer, must be PAGE_SIZE
 * @out: Pointer to output buffer
 * @outlen: Length of output buffer
 * @wrkmem: ptr to buffer for working memory, size determined by
 *          nx842_get_workmem_size()
 *
 * Returns:
 *   0		Success, output of length @outlen stored in the buffer at @out
 *   -ENOMEM	Unable to allocate internal buffers
 *   -ENOSPC	Output buffer is to small
 *   -EMSGSIZE	XXX Difficult to describe this limitation
 *   -EIO	Internal error
 *   -ENODEV	Hardware unavailable
 */
int nx842_compress(const unsigned char *in, unsigned int inlen,
		       unsigned char *out, unsigned int *outlen, void *wmem)
{
	struct nx842_header *hdr;
	struct nx842_devdata *local_devdata;
	struct device *dev = NULL;
	struct nx842_workmem *workmem;
	struct nx842_scatterlist slin, slout;
	struct nx_csbcpb *csbcpb;
	int ret = 0, max_sync_size, i, bytesleft, size, hdrsize;
	unsigned long inbuf, outbuf, padding;
	struct vio_pfo_op op = {
		.done = NULL,
		.handle = 0,
		.timeout = 0,
	};
	unsigned long start_time = get_tb();

	/*
	 * Make sure input buffer is 64k page aligned.  This is assumed since
	 * this driver is designed for page compression only (for now).  This
	 * is very nice since we can now use direct DDE(s) for the input and
	 * the alignment is guaranteed.
	*/
	inbuf = (unsigned long)in;
	if (!IS_ALIGNED(inbuf, PAGE_SIZE) || inlen != PAGE_SIZE)
		return -EINVAL;

	rcu_read_lock();
	local_devdata = rcu_dereference(devdata);
	if (!local_devdata || !local_devdata->dev) {
		rcu_read_unlock();
		return -ENODEV;
	}
	max_sync_size = local_devdata->max_sync_size;
	dev = local_devdata->dev;

	/* Create the header */
	hdr = (struct nx842_header *)out;
	hdr->blocks_nr = PAGE_SIZE / max_sync_size;
	hdrsize = nx842_header_size(hdr);
	outbuf = (unsigned long)out + hdrsize;
	bytesleft = *outlen - hdrsize;

	/* Init scatterlist */
	workmem = (struct nx842_workmem *)ALIGN((unsigned long)wmem,
		NX842_HW_PAGE_SIZE);
	slin.entries = (struct nx842_slentry *)workmem->slin;
	slout.entries = (struct nx842_slentry *)workmem->slout;

	/* Init operation */
	op.flags = NX842_OP_COMPRESS;
	csbcpb = &workmem->csbcpb;
	memset(csbcpb, 0, sizeof(*csbcpb));
	op.csbcpb = __pa(csbcpb);
	op.out = __pa(slout.entries);

	for (i = 0; i < hdr->blocks_nr; i++) {
		/*
		 * Aligning the output blocks to 128 bytes does waste space,
		 * but it prevents the need for bounce buffers and memory
		 * copies.  It also simplifies the code a lot.  In the worst
		 * case (64k page, 4k max_sync_size), you lose up to
		 * (128*16)/64k = ~3% the compression factor. For 64k
		 * max_sync_size, the loss would be at most 128/64k = ~0.2%.
		 */
		padding = ALIGN(outbuf, IO_BUFFER_ALIGN) - outbuf;
		outbuf += padding;
		bytesleft -= padding;
		if (i == 0)
			/* save offset into first block in header */
			hdr->offset = padding + hdrsize;

		if (bytesleft <= 0) {
			ret = -ENOSPC;
			goto unlock;
		}

		/*
		 * NOTE: If the default max_sync_size is changed from 4k
		 * to 64k, remove the "likely" case below, since a
		 * scatterlist will always be needed.
		 */
		if (likely(max_sync_size == NX842_HW_PAGE_SIZE)) {
			/* Create direct DDE */
			op.in = __pa(inbuf);
			op.inlen = max_sync_size;

		} else {
			/* Create indirect DDE (scatterlist) */
			nx842_build_scatterlist(inbuf, max_sync_size, &slin);
			op.in = __pa(slin.entries);
			op.inlen = -nx842_get_scatterlist_size(&slin);
		}

		/*
		 * If max_sync_size != NX842_HW_PAGE_SIZE, an indirect
		 * DDE is required for the outbuf.
		 * If max_sync_size == NX842_HW_PAGE_SIZE, outbuf must
		 * also be page aligned (1 in 128/4k=32 chance) in order
		 * to use a direct DDE.
		 * This is unlikely, just use an indirect DDE always.
		 */
		nx842_build_scatterlist(outbuf,
			min(bytesleft, max_sync_size), &slout);
		/* op.out set before loop */
		op.outlen = -nx842_get_scatterlist_size(&slout);

		/* Send request to pHyp */
		ret = vio_h_cop_sync(local_devdata->vdev, &op);

		/* Check for pHyp error */
		if (ret) {
			dev_dbg(dev, "%s: vio_h_cop_sync error (ret=%d, hret=%ld)\n",
				__func__, ret, op.hcall_err);
			ret = -EIO;
			goto unlock;
		}

		/* Check for hardware error */
		ret = nx842_validate_result(dev, &csbcpb->csb);
		if (ret && ret != -ENOSPC)
			goto unlock;

		/* Handle incompressible data */
		if (unlikely(ret == -ENOSPC)) {
			if (bytesleft < max_sync_size) {
				/*
				 * Not enough space left in the output buffer
				 * to store uncompressed block
				 */
				goto unlock;
			} else {
				/* Store incompressible block */
				memcpy((void *)outbuf, (void *)inbuf,
					max_sync_size);
				hdr->sizes[i] = -max_sync_size;
				outbuf += max_sync_size;
				bytesleft -= max_sync_size;
				/* Reset ret, incompressible data handled */
				ret = 0;
			}
		} else {
			/* Normal case, compression was successful */
			size = csbcpb->csb.processed_byte_count;
			dev_dbg(dev, "%s: processed_bytes=%d\n",
				__func__, size);
			hdr->sizes[i] = size;
			outbuf += size;
			bytesleft -= size;
		}

		inbuf += max_sync_size;
	}

	*outlen = (unsigned int)(outbuf - (unsigned long)out);

unlock:
	if (ret)
		nx842_inc_comp_failed(local_devdata);
	else {
		nx842_inc_comp_complete(local_devdata);
		ibm_nx842_incr_hist(local_devdata->counters->comp_times,
			(get_tb() - start_time) / tb_ticks_per_usec);
	}
	rcu_read_unlock();
	return ret;
}
EXPORT_SYMBOL_GPL(nx842_compress);

static int sw842_decompress(const unsigned char *, int, unsigned char *, int *,
			const void *);

/**
 * nx842_decompress - Decompress data using the 842 algorithm
 *
 * Decompression provide by the NX842 coprocessor on IBM Power systems.
 * The input buffer is decompressed and the result is stored in the
 * provided output buffer.  The size allocated to the output buffer is
 * provided by the caller of this function in @outlen.  Upon return from
 * this function @outlen contains the length of the decompressed data.
 * If there is an error then @outlen will be 0 and an error will be
 * specified by the return code from this function.
 *
 * @in: Pointer to input buffer, will use bounce buffer if not 128 byte
 *      aligned
 * @inlen: Length of input buffer
 * @out: Pointer to output buffer, must be page aligned
 * @outlen: Length of output buffer, must be PAGE_SIZE
 * @wrkmem: ptr to buffer for working memory, size determined by
 *          nx842_get_workmem_size()
 *
 * Returns:
 *   0		Success, output of length @outlen stored in the buffer at @out
 *   -ENODEV	Hardware decompression device is unavailable
 *   -ENOMEM	Unable to allocate internal buffers
 *   -ENOSPC	Output buffer is to small
 *   -EINVAL	Bad input data encountered when attempting decompress
 *   -EIO	Internal error
 */
int nx842_decompress(const unsigned char *in, unsigned int inlen,
			 unsigned char *out, unsigned int *outlen, void *wmem)
{
	struct nx842_header *hdr;
	struct nx842_devdata *local_devdata;
	struct device *dev = NULL;
	struct nx842_workmem *workmem;
	struct nx842_scatterlist slin, slout;
	struct nx_csbcpb *csbcpb;
	int ret = 0, i, size, max_sync_size;
	unsigned long inbuf, outbuf;
	struct vio_pfo_op op = {
		.done = NULL,
		.handle = 0,
		.timeout = 0,
	};
	unsigned long start_time = get_tb();

	/* Ensure page alignment and size */
	outbuf = (unsigned long)out;
	if (!IS_ALIGNED(outbuf, PAGE_SIZE) || *outlen != PAGE_SIZE)
		return -EINVAL;

	rcu_read_lock();
	local_devdata = rcu_dereference(devdata);
	if (local_devdata)
		dev = local_devdata->dev;

	/* Get header */
	hdr = (struct nx842_header *)in;

	workmem = (struct nx842_workmem *)ALIGN((unsigned long)wmem,
		NX842_HW_PAGE_SIZE);

	inbuf = (unsigned long)in + hdr->offset;
	if (likely(!IS_ALIGNED(inbuf, IO_BUFFER_ALIGN))) {
		/* Copy block(s) into bounce buffer for alignment */
		memcpy(workmem->bounce, in + hdr->offset, inlen - hdr->offset);
		inbuf = (unsigned long)workmem->bounce;
	}

	/* Init scatterlist */
	slin.entries = (struct nx842_slentry *)workmem->slin;
	slout.entries = (struct nx842_slentry *)workmem->slout;

	/* Init operation */
	op.flags = NX842_OP_DECOMPRESS;
	csbcpb = &workmem->csbcpb;
	memset(csbcpb, 0, sizeof(*csbcpb));
	op.csbcpb = __pa(csbcpb);

	/*
	 * max_sync_size may have changed since compression,
	 * so we can't read it from the device info. We need
	 * to derive it from hdr->blocks_nr.
	 */
	max_sync_size = PAGE_SIZE / hdr->blocks_nr;

	for (i = 0; i < hdr->blocks_nr; i++) {
		/* Skip padding */
		inbuf = ALIGN(inbuf, IO_BUFFER_ALIGN);

		if (hdr->sizes[i] < 0) {
			/* Negative sizes indicate uncompressed data blocks */
			size = abs(hdr->sizes[i]);
			memcpy((void *)outbuf, (void *)inbuf, size);
			outbuf += size;
			inbuf += size;
			continue;
		}

		if (!dev)
			goto sw;

		/*
		 * The better the compression, the more likely the "likely"
		 * case becomes.
		 */
		if (likely((inbuf & NX842_HW_PAGE_MASK) ==
			((inbuf + hdr->sizes[i] - 1) & NX842_HW_PAGE_MASK))) {
			/* Create direct DDE */
			op.in = __pa(inbuf);
			op.inlen = hdr->sizes[i];
		} else {
			/* Create indirect DDE (scatterlist) */
			nx842_build_scatterlist(inbuf, hdr->sizes[i] , &slin);
			op.in = __pa(slin.entries);
			op.inlen = -nx842_get_scatterlist_size(&slin);
		}

		/*
		 * NOTE: If the default max_sync_size is changed from 4k
		 * to 64k, remove the "likely" case below, since a
		 * scatterlist will always be needed.
		 */
		if (likely(max_sync_size == NX842_HW_PAGE_SIZE)) {
			/* Create direct DDE */
			op.out = __pa(outbuf);
			op.outlen = max_sync_size;
		} else {
			/* Create indirect DDE (scatterlist) */
			nx842_build_scatterlist(outbuf, max_sync_size, &slout);
			op.out = __pa(slout.entries);
			op.outlen = -nx842_get_scatterlist_size(&slout);
		}

		/* Send request to pHyp */
		ret = vio_h_cop_sync(local_devdata->vdev, &op);

		/* Check for pHyp error */
		if (ret) {
			dev_dbg(dev, "%s: vio_h_cop_sync error (ret=%d, hret=%ld)\n",
				__func__, ret, op.hcall_err);
			dev = NULL;
			goto sw;
		}

		/* Check for hardware error */
		ret = nx842_validate_result(dev, &csbcpb->csb);
		if (ret) {
			dev = NULL;
			goto sw;
		}

		/* HW decompression success */
		inbuf += hdr->sizes[i];
		outbuf += csbcpb->csb.processed_byte_count;
		continue;

sw:
		/* software decompression */
		size = max_sync_size;
		ret = sw842_decompress(
			(unsigned char *)inbuf, hdr->sizes[i],
			(unsigned char *)outbuf, &size, wmem);
		if (ret)
			pr_debug("%s: sw842_decompress failed with %d\n",
				__func__, ret);

		if (ret) {
			if (ret != -ENOSPC && ret != -EINVAL &&
					ret != -EMSGSIZE)
				ret = -EIO;
			goto unlock;
		}

		/* SW decompression success */
		inbuf += hdr->sizes[i];
		outbuf += size;
	}

	*outlen = (unsigned int)(outbuf - (unsigned long)out);

unlock:
	if (ret)
		/* decompress fail */
		nx842_inc_decomp_failed(local_devdata);
	else {
		if (!dev)
			/* software decompress */
			nx842_inc_swdecomp(local_devdata);
		nx842_inc_decomp_complete(local_devdata);
		ibm_nx842_incr_hist(local_devdata->counters->decomp_times,
			(get_tb() - start_time) / tb_ticks_per_usec);
	}

	rcu_read_unlock();
	return ret;
}
EXPORT_SYMBOL_GPL(nx842_decompress);

/**
 * nx842_OF_set_defaults -- Set default (disabled) values for devdata
 *
 * @devdata - struct nx842_devdata to update
 *
 * Returns:
 *  0 on success
 *  -ENOENT if @devdata ptr is NULL
 */
static int nx842_OF_set_defaults(struct nx842_devdata *devdata)
{
	if (devdata) {
		devdata->max_sync_size = 0;
		devdata->max_sync_sg = 0;
		devdata->max_sg_len = 0;
		devdata->status = UNAVAILABLE;
		return 0;
	} else
		return -ENOENT;
}

/**
 * nx842_OF_upd_status -- Update the device info from OF status prop
 *
 * The status property indicates if the accelerator is enabled.  If the
 * device is in the OF tree it indicates that the hardware is present.
 * The status field indicates if the device is enabled when the status
 * is 'okay'.  Otherwise the device driver will be disabled.
 *
 * @devdata - struct nx842_devdata to update
 * @prop - struct property point containing the maxsyncop for the update
 *
 * Returns:
 *  0 - Device is available
 *  -EINVAL - Device is not available
 */
static int nx842_OF_upd_status(struct nx842_devdata *devdata,
					struct property *prop) {
	int ret = 0;
	const char *status = (const char *)prop->value;

	if (!strncmp(status, "okay", (size_t)prop->length)) {
		devdata->status = AVAILABLE;
	} else {
		dev_info(devdata->dev, "%s: status '%s' is not 'okay'\n",
				__func__, status);
		devdata->status = UNAVAILABLE;
	}

	return ret;
}

/**
 * nx842_OF_upd_maxsglen -- Update the device info from OF maxsglen prop
 *
 * Definition of the 'ibm,max-sg-len' OF property:
 *  This field indicates the maximum byte length of a scatter list
 *  for the platform facility. It is a single cell encoded as with encode-int.
 *
 * Example:
 *  # od -x ibm,max-sg-len
 *  0000000 0000 0ff0
 *
 *  In this example, the maximum byte length of a scatter list is
 *  0x0ff0 (4,080).
 *
 * @devdata - struct nx842_devdata to update
 * @prop - struct property point containing the maxsyncop for the update
 *
 * Returns:
 *  0 on success
 *  -EINVAL on failure
 */
static int nx842_OF_upd_maxsglen(struct nx842_devdata *devdata,
					struct property *prop) {
	int ret = 0;
	const int *maxsglen = prop->value;

	if (prop->length != sizeof(*maxsglen)) {
		dev_err(devdata->dev, "%s: unexpected format for ibm,max-sg-len property\n", __func__);
		dev_dbg(devdata->dev, "%s: ibm,max-sg-len is %d bytes long, expected %lu bytes\n", __func__,
				prop->length, sizeof(*maxsglen));
		ret = -EINVAL;
	} else {
		devdata->max_sg_len = (unsigned int)min(*maxsglen,
				(int)NX842_HW_PAGE_SIZE);
	}

	return ret;
}

/**
 * nx842_OF_upd_maxsyncop -- Update the device info from OF maxsyncop prop
 *
 * Definition of the 'ibm,max-sync-cop' OF property:
 *  Two series of cells.  The first series of cells represents the maximums
 *  that can be synchronously compressed. The second series of cells
 *  represents the maximums that can be synchronously decompressed.
 *  1. The first cell in each series contains the count of the number of
 *     data length, scatter list elements pairs that follow – each being
 *     of the form
 *    a. One cell data byte length
 *    b. One cell total number of scatter list elements
 *
 * Example:
 *  # od -x ibm,max-sync-cop
 *  0000000 0000 0001 0000 1000 0000 01fe 0000 0001
 *  0000020 0000 1000 0000 01fe
 *
 *  In this example, compression supports 0x1000 (4,096) data byte length
 *  and 0x1fe (510) total scatter list elements.  Decompression supports
 *  0x1000 (4,096) data byte length and 0x1f3 (510) total scatter list
 *  elements.
 *
 * @devdata - struct nx842_devdata to update
 * @prop - struct property point containing the maxsyncop for the update
 *
 * Returns:
 *  0 on success
 *  -EINVAL on failure
 */
static int nx842_OF_upd_maxsyncop(struct nx842_devdata *devdata,
					struct property *prop) {
	int ret = 0;
	const struct maxsynccop_t {
		int comp_elements;
		int comp_data_limit;
		int comp_sg_limit;
		int decomp_elements;
		int decomp_data_limit;
		int decomp_sg_limit;
	} *maxsynccop;

	if (prop->length != sizeof(*maxsynccop)) {
		dev_err(devdata->dev, "%s: unexpected format for ibm,max-sync-cop property\n", __func__);
		dev_dbg(devdata->dev, "%s: ibm,max-sync-cop is %d bytes long, expected %lu bytes\n", __func__, prop->length,
				sizeof(*maxsynccop));
		ret = -EINVAL;
		goto out;
	}

	maxsynccop = (const struct maxsynccop_t *)prop->value;

	/* Use one limit rather than separate limits for compression and
	 * decompression. Set a maximum for this so as not to exceed the
	 * size that the header can support and round the value down to
	 * the hardware page size (4K) */
	devdata->max_sync_size =
			(unsigned int)min(maxsynccop->comp_data_limit,
					maxsynccop->decomp_data_limit);

	devdata->max_sync_size = min_t(unsigned int, devdata->max_sync_size,
					SIZE_64K);

	if (devdata->max_sync_size < SIZE_4K) {
		dev_err(devdata->dev, "%s: hardware max data size (%u) is "
				"less than the driver minimum, unable to use "
				"the hardware device\n",
				__func__, devdata->max_sync_size);
		ret = -EINVAL;
		goto out;
	}

	devdata->max_sync_sg = (unsigned int)min(maxsynccop->comp_sg_limit,
						maxsynccop->decomp_sg_limit);
	if (devdata->max_sync_sg < 1) {
		dev_err(devdata->dev, "%s: hardware max sg size (%u) is "
				"less than the driver minimum, unable to use "
				"the hardware device\n",
				__func__, devdata->max_sync_sg);
		ret = -EINVAL;
		goto out;
	}

out:
	return ret;
}

/**
 *
 * nx842_OF_upd -- Handle OF properties updates for the device.
 *
 * Set all properties from the OF tree.  Optionally, a new property
 * can be provided by the @new_prop pointer to overwrite an existing value.
 * The device will remain disabled until all values are valid, this function
 * will return an error for updates unless all values are valid.
 *
 * @new_prop: If not NULL, this property is being updated.  If NULL, update
 *  all properties from the current values in the OF tree.
 *
 * Returns:
 *  0 - Success
 *  -ENOMEM - Could not allocate memory for new devdata structure
 *  -EINVAL - property value not found, new_prop is not a recognized
 *	property for the device or property value is not valid.
 *  -ENODEV - Device is not available
 */
static int nx842_OF_upd(struct property *new_prop)
{
	struct nx842_devdata *old_devdata = NULL;
	struct nx842_devdata *new_devdata = NULL;
	struct device_node *of_node = NULL;
	struct property *status = NULL;
	struct property *maxsglen = NULL;
	struct property *maxsyncop = NULL;
	int ret = 0;
	unsigned long flags;

	spin_lock_irqsave(&devdata_mutex, flags);
	old_devdata = rcu_dereference_check(devdata,
			lockdep_is_held(&devdata_mutex));
	if (old_devdata)
		of_node = old_devdata->dev->of_node;

	if (!old_devdata || !of_node) {
		pr_err("%s: device is not available\n", __func__);
		spin_unlock_irqrestore(&devdata_mutex, flags);
		return -ENODEV;
	}

	new_devdata = kzalloc(sizeof(*new_devdata), GFP_NOFS);
	if (!new_devdata) {
		dev_err(old_devdata->dev, "%s: Could not allocate memory for device data\n", __func__);
		ret = -ENOMEM;
		goto error_out;
	}

	memcpy(new_devdata, old_devdata, sizeof(*old_devdata));
	new_devdata->counters = old_devdata->counters;

	/* Set ptrs for existing properties */
	status = of_find_property(of_node, "status", NULL);
	maxsglen = of_find_property(of_node, "ibm,max-sg-len", NULL);
	maxsyncop = of_find_property(of_node, "ibm,max-sync-cop", NULL);
	if (!status || !maxsglen || !maxsyncop) {
		dev_err(old_devdata->dev, "%s: Could not locate device properties\n", __func__);
		ret = -EINVAL;
		goto error_out;
	}

	/* Set ptr to new property if provided */
	if (new_prop) {
		/* Single property */
		if (!strncmp(new_prop->name, "status", new_prop->length)) {
			status = new_prop;

		} else if (!strncmp(new_prop->name, "ibm,max-sg-len",
					new_prop->length)) {
			maxsglen = new_prop;

		} else if (!strncmp(new_prop->name, "ibm,max-sync-cop",
					new_prop->length)) {
			maxsyncop = new_prop;

		} else {
			/*
			 * Skip the update, the property being updated
			 * has no impact.
			 */
			goto out;
		}
	}

	/* Perform property updates */
	ret = nx842_OF_upd_status(new_devdata, status);
	if (ret)
		goto error_out;

	ret = nx842_OF_upd_maxsglen(new_devdata, maxsglen);
	if (ret)
		goto error_out;

	ret = nx842_OF_upd_maxsyncop(new_devdata, maxsyncop);
	if (ret)
		goto error_out;

out:
	dev_info(old_devdata->dev, "%s: max_sync_size new:%u old:%u\n",
			__func__, new_devdata->max_sync_size,
			old_devdata->max_sync_size);
	dev_info(old_devdata->dev, "%s: max_sync_sg new:%u old:%u\n",
			__func__, new_devdata->max_sync_sg,
			old_devdata->max_sync_sg);
	dev_info(old_devdata->dev, "%s: max_sg_len new:%u old:%u\n",
			__func__, new_devdata->max_sg_len,
			old_devdata->max_sg_len);

	rcu_assign_pointer(devdata, new_devdata);
	spin_unlock_irqrestore(&devdata_mutex, flags);
	synchronize_rcu();
	dev_set_drvdata(new_devdata->dev, new_devdata);
	kfree(old_devdata);
	return 0;

error_out:
	if (new_devdata) {
		dev_info(old_devdata->dev, "%s: device disabled\n", __func__);
		nx842_OF_set_defaults(new_devdata);
		rcu_assign_pointer(devdata, new_devdata);
		spin_unlock_irqrestore(&devdata_mutex, flags);
		synchronize_rcu();
		dev_set_drvdata(new_devdata->dev, new_devdata);
		kfree(old_devdata);
	} else {
		dev_err(old_devdata->dev, "%s: could not update driver from hardware\n", __func__);
		spin_unlock_irqrestore(&devdata_mutex, flags);
	}

	if (!ret)
		ret = -EINVAL;
	return ret;
}

/**
 * nx842_OF_notifier - Process updates to OF properties for the device
 *
 * @np: notifier block
 * @action: notifier action
 * @update: struct pSeries_reconfig_prop_update pointer if action is
 *	PSERIES_UPDATE_PROPERTY
 *
 * Returns:
 *	NOTIFY_OK on success
 *	NOTIFY_BAD encoded with error number on failure, use
 *		notifier_to_errno() to decode this value
 */
static int nx842_OF_notifier(struct notifier_block *np, unsigned long action,
			     void *update)
{
	struct of_prop_reconfig *upd = update;
	struct nx842_devdata *local_devdata;
	struct device_node *node = NULL;

	rcu_read_lock();
	local_devdata = rcu_dereference(devdata);
	if (local_devdata)
		node = local_devdata->dev->of_node;

	if (local_devdata &&
			action == OF_RECONFIG_UPDATE_PROPERTY &&
			!strcmp(upd->dn->name, node->name)) {
		rcu_read_unlock();
		nx842_OF_upd(upd->prop);
	} else
		rcu_read_unlock();

	return NOTIFY_OK;
}

static struct notifier_block nx842_of_nb = {
	.notifier_call = nx842_OF_notifier,
};

#define nx842_counter_read(_name)					\
static ssize_t nx842_##_name##_show(struct device *dev,		\
		struct device_attribute *attr,				\
		char *buf) {						\
	struct nx842_devdata *local_devdata;			\
	int p = 0;							\
	rcu_read_lock();						\
	local_devdata = rcu_dereference(devdata);			\
	if (local_devdata)						\
		p = snprintf(buf, PAGE_SIZE, "%ld\n",			\
		       atomic64_read(&local_devdata->counters->_name));	\
	rcu_read_unlock();						\
	return p;							\
}

#define NX842DEV_COUNTER_ATTR_RO(_name)					\
	nx842_counter_read(_name);					\
	static struct device_attribute dev_attr_##_name = __ATTR(_name,	\
						0444,			\
						nx842_##_name##_show,\
						NULL);

NX842DEV_COUNTER_ATTR_RO(comp_complete);
NX842DEV_COUNTER_ATTR_RO(comp_failed);
NX842DEV_COUNTER_ATTR_RO(decomp_complete);
NX842DEV_COUNTER_ATTR_RO(decomp_failed);
NX842DEV_COUNTER_ATTR_RO(swdecomp);

static ssize_t nx842_timehist_show(struct device *,
		struct device_attribute *, char *);

static struct device_attribute dev_attr_comp_times = __ATTR(comp_times, 0444,
		nx842_timehist_show, NULL);
static struct device_attribute dev_attr_decomp_times = __ATTR(decomp_times,
		0444, nx842_timehist_show, NULL);

static ssize_t nx842_timehist_show(struct device *dev,
		struct device_attribute *attr, char *buf) {
	char *p = buf;
	struct nx842_devdata *local_devdata;
	atomic64_t *times;
	int bytes_remain = PAGE_SIZE;
	int bytes;
	int i;

	rcu_read_lock();
	local_devdata = rcu_dereference(devdata);
	if (!local_devdata) {
		rcu_read_unlock();
		return 0;
	}

	if (attr == &dev_attr_comp_times)
		times = local_devdata->counters->comp_times;
	else if (attr == &dev_attr_decomp_times)
		times = local_devdata->counters->decomp_times;
	else {
		rcu_read_unlock();
		return 0;
	}

	for (i = 0; i < (NX842_HIST_SLOTS - 2); i++) {
		bytes = snprintf(p, bytes_remain, "%u-%uus:\t%ld\n",
			       i ? (2<<(i-1)) : 0, (2<<i)-1,
			       atomic64_read(&times[i]));
		bytes_remain -= bytes;
		p += bytes;
	}
	/* The last bucket holds everything over
	 * 2<<(NX842_HIST_SLOTS - 2) us */
	bytes = snprintf(p, bytes_remain, "%uus - :\t%ld\n",
			2<<(NX842_HIST_SLOTS - 2),
			atomic64_read(&times[(NX842_HIST_SLOTS - 1)]));
	p += bytes;

	rcu_read_unlock();
	return p - buf;
}

static struct attribute *nx842_sysfs_entries[] = {
	&dev_attr_comp_complete.attr,
	&dev_attr_comp_failed.attr,
	&dev_attr_decomp_complete.attr,
	&dev_attr_decomp_failed.attr,
	&dev_attr_swdecomp.attr,
	&dev_attr_comp_times.attr,
	&dev_attr_decomp_times.attr,
	NULL,
};

static struct attribute_group nx842_attribute_group = {
	.name = NULL,		/* put in device directory */
	.attrs = nx842_sysfs_entries,
};

static int __init nx842_probe(struct vio_dev *viodev,
				  const struct vio_device_id *id)
{
	struct nx842_devdata *old_devdata, *new_devdata = NULL;
	unsigned long flags;
	int ret = 0;

	spin_lock_irqsave(&devdata_mutex, flags);
	old_devdata = rcu_dereference_check(devdata,
			lockdep_is_held(&devdata_mutex));

	if (old_devdata && old_devdata->vdev != NULL) {
		dev_err(&viodev->dev, "%s: Attempt to register more than one instance of the hardware\n", __func__);
		ret = -1;
		goto error_unlock;
	}

	dev_set_drvdata(&viodev->dev, NULL);

	new_devdata = kzalloc(sizeof(*new_devdata), GFP_NOFS);
	if (!new_devdata) {
		dev_err(&viodev->dev, "%s: Could not allocate memory for device data\n", __func__);
		ret = -ENOMEM;
		goto error_unlock;
	}

	new_devdata->counters = kzalloc(sizeof(*new_devdata->counters),
			GFP_NOFS);
	if (!new_devdata->counters) {
		dev_err(&viodev->dev, "%s: Could not allocate memory for performance counters\n", __func__);
		ret = -ENOMEM;
		goto error_unlock;
	}

	new_devdata->vdev = viodev;
	new_devdata->dev = &viodev->dev;
	nx842_OF_set_defaults(new_devdata);

	rcu_assign_pointer(devdata, new_devdata);
	spin_unlock_irqrestore(&devdata_mutex, flags);
	synchronize_rcu();
	kfree(old_devdata);

	of_reconfig_notifier_register(&nx842_of_nb);

	ret = nx842_OF_upd(NULL);
	if (ret && ret != -ENODEV) {
		dev_err(&viodev->dev, "could not parse device tree. %d\n", ret);
		ret = -1;
		goto error;
	}

	rcu_read_lock();
	if (dev_set_drvdata(&viodev->dev, rcu_dereference(devdata))) {
		rcu_read_unlock();
		dev_err(&viodev->dev, "failed to set driver data for device\n");
		ret = -1;
		goto error;
	}
	rcu_read_unlock();

	if (sysfs_create_group(&viodev->dev.kobj, &nx842_attribute_group)) {
		dev_err(&viodev->dev, "could not create sysfs device attributes\n");
		ret = -1;
		goto error;
	}

	return 0;

error_unlock:
	spin_unlock_irqrestore(&devdata_mutex, flags);
	if (new_devdata)
		kfree(new_devdata->counters);
	kfree(new_devdata);
error:
	return ret;
}

static int __exit nx842_remove(struct vio_dev *viodev)
{
	struct nx842_devdata *old_devdata;
	unsigned long flags;

	pr_info("Removing IBM Power 842 compression device\n");
	sysfs_remove_group(&viodev->dev.kobj, &nx842_attribute_group);

	spin_lock_irqsave(&devdata_mutex, flags);
	old_devdata = rcu_dereference_check(devdata,
			lockdep_is_held(&devdata_mutex));
	of_reconfig_notifier_unregister(&nx842_of_nb);
	rcu_assign_pointer(devdata, NULL);
	spin_unlock_irqrestore(&devdata_mutex, flags);
	synchronize_rcu();
	dev_set_drvdata(&viodev->dev, NULL);
	if (old_devdata)
		kfree(old_devdata->counters);
	kfree(old_devdata);
	return 0;
}

static struct vio_device_id nx842_driver_ids[] = {
	{"ibm,compression-v1", "ibm,compression"},
	{"", ""},
};

static struct vio_driver nx842_driver = {
	.name = MODULE_NAME,
	.probe = nx842_probe,
	.remove = nx842_remove,
	.get_desired_dma = nx842_get_desired_dma,
	.id_table = nx842_driver_ids,
};

static int __init nx842_init(void)
{
	struct nx842_devdata *new_devdata;
	pr_info("Registering IBM Power 842 compression driver\n");

	RCU_INIT_POINTER(devdata, NULL);
	new_devdata = kzalloc(sizeof(*new_devdata), GFP_KERNEL);
	if (!new_devdata) {
		pr_err("Could not allocate memory for device data\n");
		return -ENOMEM;
	}
	new_devdata->status = UNAVAILABLE;
	RCU_INIT_POINTER(devdata, new_devdata);

	return vio_register_driver(&nx842_driver);
}

module_init(nx842_init);

static void __exit nx842_exit(void)
{
	struct nx842_devdata *old_devdata;
	unsigned long flags;

	pr_info("Exiting IBM Power 842 compression driver\n");
	spin_lock_irqsave(&devdata_mutex, flags);
	old_devdata = rcu_dereference_check(devdata,
			lockdep_is_held(&devdata_mutex));
	rcu_assign_pointer(devdata, NULL);
	spin_unlock_irqrestore(&devdata_mutex, flags);
	synchronize_rcu();
	if (old_devdata)
		dev_set_drvdata(old_devdata->dev, NULL);
	kfree(old_devdata);
	vio_unregister_driver(&nx842_driver);
}

module_exit(nx842_exit);

/*********************************
 * 842 software decompressor
*********************************/
typedef int (*sw842_template_op)(const char **, int *, unsigned char **,
						struct sw842_fifo *);

static int sw842_data8(const char **, int *, unsigned char **,
						struct sw842_fifo *);
static int sw842_data4(const char **, int *, unsigned char **,
						struct sw842_fifo *);
static int sw842_data2(const char **, int *, unsigned char **,
						struct sw842_fifo *);
static int sw842_ptr8(const char **, int *, unsigned char **,
						struct sw842_fifo *);
static int sw842_ptr4(const char **, int *, unsigned char **,
						struct sw842_fifo *);
static int sw842_ptr2(const char **, int *, unsigned char **,
						struct sw842_fifo *);

/* special templates */
#define SW842_TMPL_REPEAT 0x1B
#define SW842_TMPL_ZEROS 0x1C
#define SW842_TMPL_EOF 0x1E

static sw842_template_op sw842_tmpl_ops[26][4] = {
	{ sw842_data8, NULL}, /* 0 (00000) */
	{ sw842_data4, sw842_data2, sw842_ptr2,  NULL},
	{ sw842_data4, sw842_ptr2,  sw842_data2, NULL},
	{ sw842_data4, sw842_ptr2,  sw842_ptr2,  NULL},
	{ sw842_data4, sw842_ptr4,  NULL},
	{ sw842_data2, sw842_ptr2,  sw842_data4, NULL},
	{ sw842_data2, sw842_ptr2,  sw842_data2, sw842_ptr2},
	{ sw842_data2, sw842_ptr2,  sw842_ptr2,  sw842_data2},
	{ sw842_data2, sw842_ptr2,  sw842_ptr2,  sw842_ptr2,},
	{ sw842_data2, sw842_ptr2,  sw842_ptr4,  NULL},
	{ sw842_ptr2,  sw842_data2, sw842_data4, NULL}, /* 10 (01010) */
	{ sw842_ptr2,  sw842_data4, sw842_ptr2,  NULL},
	{ sw842_ptr2,  sw842_data2, sw842_ptr2,  sw842_data2},
	{ sw842_ptr2,  sw842_data2, sw842_ptr2,  sw842_ptr2},
	{ sw842_ptr2,  sw842_data2, sw842_ptr4,  NULL},
	{ sw842_ptr2,  sw842_ptr2,  sw842_data4, NULL},
	{ sw842_ptr2,  sw842_ptr2,  sw842_data2, sw842_ptr2},
	{ sw842_ptr2,  sw842_ptr2,  sw842_ptr2,  sw842_data2},
	{ sw842_ptr2,  sw842_ptr2,  sw842_ptr2,  sw842_ptr2},
	{ sw842_ptr2,  sw842_ptr2,  sw842_ptr4,  NULL},
	{ sw842_ptr4,  sw842_data4, NULL}, /* 20 (10100) */
	{ sw842_ptr4,  sw842_data2, sw842_ptr2,  NULL},
	{ sw842_ptr4,  sw842_ptr2,  sw842_data2, NULL},
	{ sw842_ptr4,  sw842_ptr2,  sw842_ptr2,  NULL},
	{ sw842_ptr4,  sw842_ptr4,  NULL},
	{ sw842_ptr8,  NULL}
};

/* Software decompress helpers */

static uint8_t sw842_get_byte(const char *buf, int bit)
{
	uint8_t tmpl;
	uint16_t tmp;
	tmp = htons(*(uint16_t *)(buf));
	tmp = (uint16_t)(tmp << bit);
	tmp = ntohs(tmp);
	memcpy(&tmpl, &tmp, 1);
	return tmpl;
}

static uint8_t sw842_get_template(const char **buf, int *bit)
{
	uint8_t byte;
	byte = sw842_get_byte(*buf, *bit);
	byte = byte >> 3;
	byte &= 0x1F;
	*buf += (*bit + 5) / 8;
	*bit = (*bit + 5) % 8;
	return byte;
}

/* repeat_count happens to be 5-bit too (like the template) */
static uint8_t sw842_get_repeat_count(const char **buf, int *bit)
{
	uint8_t byte;
	byte = sw842_get_byte(*buf, *bit);
	byte = byte >> 2;
	byte &= 0x3F;
	*buf += (*bit + 6) / 8;
	*bit = (*bit + 6) % 8;
	return byte;
}

static uint8_t sw842_get_ptr2(const char **buf, int *bit)
{
	uint8_t ptr;
	ptr = sw842_get_byte(*buf, *bit);
	(*buf)++;
	return ptr;
}

static uint16_t sw842_get_ptr4(const char **buf, int *bit,
		struct sw842_fifo *fifo)
{
	uint16_t ptr;
	ptr = htons(*(uint16_t *)(*buf));
	ptr = (uint16_t)(ptr << *bit);
	ptr = ptr >> 7;
	ptr &= 0x01FF;
	*buf += (*bit + 9) / 8;
	*bit = (*bit + 9) % 8;
	return ptr;
}

static uint8_t sw842_get_ptr8(const char **buf, int *bit,
		struct sw842_fifo *fifo)
{
	return sw842_get_ptr2(buf, bit);
}

/* Software decompress template ops */

static int sw842_data8(const char **inbuf, int *inbit,
		unsigned char **outbuf, struct sw842_fifo *fifo)
{
	int ret;

	ret = sw842_data4(inbuf, inbit, outbuf, fifo);
	if (ret)
		return ret;
	ret = sw842_data4(inbuf, inbit, outbuf, fifo);
	return ret;
}

static int sw842_data4(const char **inbuf, int *inbit,
		unsigned char **outbuf, struct sw842_fifo *fifo)
{
	int ret;

	ret = sw842_data2(inbuf, inbit, outbuf, fifo);
	if (ret)
		return ret;
	ret = sw842_data2(inbuf, inbit, outbuf, fifo);
	return ret;
}

static int sw842_data2(const char **inbuf, int *inbit,
		unsigned char **outbuf, struct sw842_fifo *fifo)
{
	**outbuf = sw842_get_byte(*inbuf, *inbit);
	(*inbuf)++;
	(*outbuf)++;
	**outbuf = sw842_get_byte(*inbuf, *inbit);
	(*inbuf)++;
	(*outbuf)++;
	return 0;
}

static int sw842_ptr8(const char **inbuf, int *inbit,
		unsigned char **outbuf, struct sw842_fifo *fifo)
{
	uint8_t ptr;
	ptr = sw842_get_ptr8(inbuf, inbit, fifo);
	if (!fifo->f84_full && (ptr >= fifo->f8_count))
		return 1;
	memcpy(*outbuf, fifo->f8[ptr], 8);
	*outbuf += 8;
	return 0;
}

static int sw842_ptr4(const char **inbuf, int *inbit,
		unsigned char **outbuf, struct sw842_fifo *fifo)
{
	uint16_t ptr;
	ptr = sw842_get_ptr4(inbuf, inbit, fifo);
	if (!fifo->f84_full && (ptr >= fifo->f4_count))
		return 1;
	memcpy(*outbuf, fifo->f4[ptr], 4);
	*outbuf += 4;
	return 0;
}

static int sw842_ptr2(const char **inbuf, int *inbit,
		unsigned char **outbuf, struct sw842_fifo *fifo)
{
	uint8_t ptr;
	ptr = sw842_get_ptr2(inbuf, inbit);
	if (!fifo->f2_full && (ptr >= fifo->f2_count))
		return 1;
	memcpy(*outbuf, fifo->f2[ptr], 2);
	*outbuf += 2;
	return 0;
}

static void sw842_copy_to_fifo(const char *buf, struct sw842_fifo *fifo)
{
	unsigned char initial_f2count = fifo->f2_count;

	memcpy(fifo->f8[fifo->f8_count], buf, 8);
	fifo->f4_count += 2;
	fifo->f8_count += 1;

	if (!fifo->f84_full && fifo->f4_count >= 512) {
		fifo->f84_full = 1;
		fifo->f4_count /= 512;
	}

	memcpy(fifo->f2[fifo->f2_count++], buf, 2);
	memcpy(fifo->f2[fifo->f2_count++], buf + 2, 2);
	memcpy(fifo->f2[fifo->f2_count++], buf + 4, 2);
	memcpy(fifo->f2[fifo->f2_count++], buf + 6, 2);
	if (fifo->f2_count < initial_f2count)
		fifo->f2_full = 1;
}

static int sw842_decompress(const unsigned char *src, int srclen,
			unsigned char *dst, int *destlen,
			const void *wrkmem)
{
	uint8_t tmpl;
	const char *inbuf;
	int inbit = 0;
	unsigned char *outbuf, *outbuf_end, *origbuf, *prevbuf;
	const char *inbuf_end;
	sw842_template_op op;
	int opindex;
	int i, repeat_count;
	struct sw842_fifo *fifo;
	int ret = 0;

	fifo = &((struct nx842_workmem *)(wrkmem))->swfifo;
	memset(fifo, 0, sizeof(*fifo));

	origbuf = NULL;
	inbuf = src;
	inbuf_end = src + srclen;
	outbuf = dst;
	outbuf_end = dst + *destlen;

	while ((tmpl = sw842_get_template(&inbuf, &inbit)) != SW842_TMPL_EOF) {
		if (inbuf >= inbuf_end) {
			ret = -EINVAL;
			goto out;
		}

		opindex = 0;
		prevbuf = origbuf;
		origbuf = outbuf;
		switch (tmpl) {
		case SW842_TMPL_REPEAT:
			if (prevbuf == NULL) {
				ret = -EINVAL;
				goto out;
			}

			repeat_count = sw842_get_repeat_count(&inbuf,
								&inbit) + 1;

			/* Did the repeat count advance past the end of input */
			if (inbuf > inbuf_end) {
				ret = -EINVAL;
				goto out;
			}

			for (i = 0; i < repeat_count; i++) {
				/* Would this overflow the output buffer */
				if ((outbuf + 8) > outbuf_end) {
					ret = -ENOSPC;
					goto out;
				}

				memcpy(outbuf, prevbuf, 8);
				sw842_copy_to_fifo(outbuf, fifo);
				outbuf += 8;
			}
			break;

		case SW842_TMPL_ZEROS:
			/* Would this overflow the output buffer */
			if ((outbuf + 8) > outbuf_end) {
				ret = -ENOSPC;
				goto out;
			}

			memset(outbuf, 0, 8);
			sw842_copy_to_fifo(outbuf, fifo);
			outbuf += 8;
			break;

		default:
			if (tmpl > 25) {
				ret = -EINVAL;
				goto out;
			}

			/* Does this go past the end of the input buffer */
			if ((inbuf + 2) > inbuf_end) {
				ret = -EINVAL;
				goto out;
			}

			/* Would this overflow the output buffer */
			if ((outbuf + 8) > outbuf_end) {
				ret = -ENOSPC;
				goto out;
			}

			while (opindex < 4 &&
				(op = sw842_tmpl_ops[tmpl][opindex++])
					!= NULL) {
				ret = (*op)(&inbuf, &inbit, &outbuf, fifo);
				if (ret) {
					ret = -EINVAL;
					goto out;
				}
				sw842_copy_to_fifo(origbuf, fifo);
			}
		}
	}

out:
	if (!ret)
		*destlen = (unsigned int)(outbuf - dst);
	else
		*destlen = 0;

	return ret;
}