summaryrefslogtreecommitdiff
path: root/drivers/macintosh/smu.c
blob: b495bfa7789625ad5d7bf9101ae2d45167b843e2 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * PowerMac G5 SMU driver
 *
 * Copyright 2004 J. Mayer <l_indien@magic.fr>
 * Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
 */

/*
 * TODO:
 *  - maybe add timeout to commands ?
 *  - blocking version of time functions
 *  - polling version of i2c commands (including timer that works with
 *    interrupts off)
 *  - maybe avoid some data copies with i2c by directly using the smu cmd
 *    buffer and a lower level internal interface
 *  - understand SMU -> CPU events and implement reception of them via
 *    the userland interface
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/dmapool.h>
#include <linux/memblock.h>
#include <linux/vmalloc.h>
#include <linux/highmem.h>
#include <linux/jiffies.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/completion.h>
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>

#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/pmac_feature.h>
#include <asm/smu.h>
#include <asm/sections.h>
#include <linux/uaccess.h>

#define VERSION "0.7"
#define AUTHOR  "(c) 2005 Benjamin Herrenschmidt, IBM Corp."

#undef DEBUG_SMU

#ifdef DEBUG_SMU
#define DPRINTK(fmt, args...) do { printk(KERN_DEBUG fmt , ##args); } while (0)
#else
#define DPRINTK(fmt, args...) do { } while (0)
#endif

/*
 * This is the command buffer passed to the SMU hardware
 */
#define SMU_MAX_DATA	254

struct smu_cmd_buf {
	u8 cmd;
	u8 length;
	u8 data[SMU_MAX_DATA];
};

struct smu_device {
	spinlock_t		lock;
	struct device_node	*of_node;
	struct platform_device	*of_dev;
	int			doorbell;	/* doorbell gpio */
	u32 __iomem		*db_buf;	/* doorbell buffer */
	struct device_node	*db_node;
	unsigned int		db_irq;
	int			msg;
	struct device_node	*msg_node;
	unsigned int		msg_irq;
	struct smu_cmd_buf	*cmd_buf;	/* command buffer virtual */
	u32			cmd_buf_abs;	/* command buffer absolute */
	struct list_head	cmd_list;
	struct smu_cmd		*cmd_cur;	/* pending command */
	int			broken_nap;
	struct list_head	cmd_i2c_list;
	struct smu_i2c_cmd	*cmd_i2c_cur;	/* pending i2c command */
	struct timer_list	i2c_timer;
};

/*
 * I don't think there will ever be more than one SMU, so
 * for now, just hard code that
 */
static DEFINE_MUTEX(smu_mutex);
static struct smu_device	*smu;
static DEFINE_MUTEX(smu_part_access);
static int smu_irq_inited;
static unsigned long smu_cmdbuf_abs;

static void smu_i2c_retry(struct timer_list *t);

/*
 * SMU driver low level stuff
 */

static void smu_start_cmd(void)
{
	unsigned long faddr, fend;
	struct smu_cmd *cmd;

	if (list_empty(&smu->cmd_list))
		return;

	/* Fetch first command in queue */
	cmd = list_entry(smu->cmd_list.next, struct smu_cmd, link);
	smu->cmd_cur = cmd;
	list_del(&cmd->link);

	DPRINTK("SMU: starting cmd %x, %d bytes data\n", cmd->cmd,
		cmd->data_len);
	DPRINTK("SMU: data buffer: %8ph\n", cmd->data_buf);

	/* Fill the SMU command buffer */
	smu->cmd_buf->cmd = cmd->cmd;
	smu->cmd_buf->length = cmd->data_len;
	memcpy(smu->cmd_buf->data, cmd->data_buf, cmd->data_len);

	/* Flush command and data to RAM */
	faddr = (unsigned long)smu->cmd_buf;
	fend = faddr + smu->cmd_buf->length + 2;
	flush_dcache_range(faddr, fend);


	/* We also disable NAP mode for the duration of the command
	 * on U3 based machines.
	 * This is slightly racy as it can be written back to 1 by a sysctl
	 * but that never happens in practice. There seem to be an issue with
	 * U3 based machines such as the iMac G5 where napping for the
	 * whole duration of the command prevents the SMU from fetching it
	 * from memory. This might be related to the strange i2c based
	 * mechanism the SMU uses to access memory.
	 */
	if (smu->broken_nap)
		powersave_nap = 0;

	/* This isn't exactly a DMA mapping here, I suspect
	 * the SMU is actually communicating with us via i2c to the
	 * northbridge or the CPU to access RAM.
	 */
	writel(smu->cmd_buf_abs, smu->db_buf);

	/* Ring the SMU doorbell */
	pmac_do_feature_call(PMAC_FTR_WRITE_GPIO, NULL, smu->doorbell, 4);
}


static irqreturn_t smu_db_intr(int irq, void *arg)
{
	unsigned long flags;
	struct smu_cmd *cmd;
	void (*done)(struct smu_cmd *cmd, void *misc) = NULL;
	void *misc = NULL;
	u8 gpio;
	int rc = 0;

	/* SMU completed the command, well, we hope, let's make sure
	 * of it
	 */
	spin_lock_irqsave(&smu->lock, flags);

	gpio = pmac_do_feature_call(PMAC_FTR_READ_GPIO, NULL, smu->doorbell);
	if ((gpio & 7) != 7) {
		spin_unlock_irqrestore(&smu->lock, flags);
		return IRQ_HANDLED;
	}

	cmd = smu->cmd_cur;
	smu->cmd_cur = NULL;
	if (cmd == NULL)
		goto bail;

	if (rc == 0) {
		unsigned long faddr;
		int reply_len;
		u8 ack;

		/* CPU might have brought back the cache line, so we need
		 * to flush again before peeking at the SMU response. We
		 * flush the entire buffer for now as we haven't read the
		 * reply length (it's only 2 cache lines anyway)
		 */
		faddr = (unsigned long)smu->cmd_buf;
		flush_dcache_range(faddr, faddr + 256);

		/* Now check ack */
		ack = (~cmd->cmd) & 0xff;
		if (ack != smu->cmd_buf->cmd) {
			DPRINTK("SMU: incorrect ack, want %x got %x\n",
				ack, smu->cmd_buf->cmd);
			rc = -EIO;
		}
		reply_len = rc == 0 ? smu->cmd_buf->length : 0;
		DPRINTK("SMU: reply len: %d\n", reply_len);
		if (reply_len > cmd->reply_len) {
			printk(KERN_WARNING "SMU: reply buffer too small,"
			       "got %d bytes for a %d bytes buffer\n",
			       reply_len, cmd->reply_len);
			reply_len = cmd->reply_len;
		}
		cmd->reply_len = reply_len;
		if (cmd->reply_buf && reply_len)
			memcpy(cmd->reply_buf, smu->cmd_buf->data, reply_len);
	}

	/* Now complete the command. Write status last in order as we lost
	 * ownership of the command structure as soon as it's no longer -1
	 */
	done = cmd->done;
	misc = cmd->misc;
	mb();
	cmd->status = rc;

	/* Re-enable NAP mode */
	if (smu->broken_nap)
		powersave_nap = 1;
 bail:
	/* Start next command if any */
	smu_start_cmd();
	spin_unlock_irqrestore(&smu->lock, flags);

	/* Call command completion handler if any */
	if (done)
		done(cmd, misc);

	/* It's an edge interrupt, nothing to do */
	return IRQ_HANDLED;
}


static irqreturn_t smu_msg_intr(int irq, void *arg)
{
	/* I don't quite know what to do with this one, we seem to never
	 * receive it, so I suspect we have to arm it someway in the SMU
	 * to start getting events that way.
	 */

	printk(KERN_INFO "SMU: message interrupt !\n");

	/* It's an edge interrupt, nothing to do */
	return IRQ_HANDLED;
}


/*
 * Queued command management.
 *
 */

int smu_queue_cmd(struct smu_cmd *cmd)
{
	unsigned long flags;

	if (smu == NULL)
		return -ENODEV;
	if (cmd->data_len > SMU_MAX_DATA ||
	    cmd->reply_len > SMU_MAX_DATA)
		return -EINVAL;

	cmd->status = 1;
	spin_lock_irqsave(&smu->lock, flags);
	list_add_tail(&cmd->link, &smu->cmd_list);
	if (smu->cmd_cur == NULL)
		smu_start_cmd();
	spin_unlock_irqrestore(&smu->lock, flags);

	/* Workaround for early calls when irq isn't available */
	if (!smu_irq_inited || !smu->db_irq)
		smu_spinwait_cmd(cmd);

	return 0;
}
EXPORT_SYMBOL(smu_queue_cmd);


int smu_queue_simple(struct smu_simple_cmd *scmd, u8 command,
		     unsigned int data_len,
		     void (*done)(struct smu_cmd *cmd, void *misc),
		     void *misc, ...)
{
	struct smu_cmd *cmd = &scmd->cmd;
	va_list list;
	int i;

	if (data_len > sizeof(scmd->buffer))
		return -EINVAL;

	memset(scmd, 0, sizeof(*scmd));
	cmd->cmd = command;
	cmd->data_len = data_len;
	cmd->data_buf = scmd->buffer;
	cmd->reply_len = sizeof(scmd->buffer);
	cmd->reply_buf = scmd->buffer;
	cmd->done = done;
	cmd->misc = misc;

	va_start(list, misc);
	for (i = 0; i < data_len; ++i)
		scmd->buffer[i] = (u8)va_arg(list, int);
	va_end(list);

	return smu_queue_cmd(cmd);
}
EXPORT_SYMBOL(smu_queue_simple);


void smu_poll(void)
{
	u8 gpio;

	if (smu == NULL)
		return;

	gpio = pmac_do_feature_call(PMAC_FTR_READ_GPIO, NULL, smu->doorbell);
	if ((gpio & 7) == 7)
		smu_db_intr(smu->db_irq, smu);
}
EXPORT_SYMBOL(smu_poll);


void smu_done_complete(struct smu_cmd *cmd, void *misc)
{
	struct completion *comp = misc;

	complete(comp);
}
EXPORT_SYMBOL(smu_done_complete);


void smu_spinwait_cmd(struct smu_cmd *cmd)
{
	while(cmd->status == 1)
		smu_poll();
}
EXPORT_SYMBOL(smu_spinwait_cmd);


/* RTC low level commands */
static inline int bcd2hex (int n)
{
	return (((n & 0xf0) >> 4) * 10) + (n & 0xf);
}


static inline int hex2bcd (int n)
{
	return ((n / 10) << 4) + (n % 10);
}


static inline void smu_fill_set_rtc_cmd(struct smu_cmd_buf *cmd_buf,
					struct rtc_time *time)
{
	cmd_buf->cmd = 0x8e;
	cmd_buf->length = 8;
	cmd_buf->data[0] = 0x80;
	cmd_buf->data[1] = hex2bcd(time->tm_sec);
	cmd_buf->data[2] = hex2bcd(time->tm_min);
	cmd_buf->data[3] = hex2bcd(time->tm_hour);
	cmd_buf->data[4] = time->tm_wday;
	cmd_buf->data[5] = hex2bcd(time->tm_mday);
	cmd_buf->data[6] = hex2bcd(time->tm_mon) + 1;
	cmd_buf->data[7] = hex2bcd(time->tm_year - 100);
}


int smu_get_rtc_time(struct rtc_time *time, int spinwait)
{
	struct smu_simple_cmd cmd;
	int rc;

	if (smu == NULL)
		return -ENODEV;

	memset(time, 0, sizeof(struct rtc_time));
	rc = smu_queue_simple(&cmd, SMU_CMD_RTC_COMMAND, 1, NULL, NULL,
			      SMU_CMD_RTC_GET_DATETIME);
	if (rc)
		return rc;
	smu_spinwait_simple(&cmd);

	time->tm_sec = bcd2hex(cmd.buffer[0]);
	time->tm_min = bcd2hex(cmd.buffer[1]);
	time->tm_hour = bcd2hex(cmd.buffer[2]);
	time->tm_wday = bcd2hex(cmd.buffer[3]);
	time->tm_mday = bcd2hex(cmd.buffer[4]);
	time->tm_mon = bcd2hex(cmd.buffer[5]) - 1;
	time->tm_year = bcd2hex(cmd.buffer[6]) + 100;

	return 0;
}


int smu_set_rtc_time(struct rtc_time *time, int spinwait)
{
	struct smu_simple_cmd cmd;
	int rc;

	if (smu == NULL)
		return -ENODEV;

	rc = smu_queue_simple(&cmd, SMU_CMD_RTC_COMMAND, 8, NULL, NULL,
			      SMU_CMD_RTC_SET_DATETIME,
			      hex2bcd(time->tm_sec),
			      hex2bcd(time->tm_min),
			      hex2bcd(time->tm_hour),
			      time->tm_wday,
			      hex2bcd(time->tm_mday),
			      hex2bcd(time->tm_mon) + 1,
			      hex2bcd(time->tm_year - 100));
	if (rc)
		return rc;
	smu_spinwait_simple(&cmd);

	return 0;
}


void smu_shutdown(void)
{
	struct smu_simple_cmd cmd;

	if (smu == NULL)
		return;

	if (smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 9, NULL, NULL,
			     'S', 'H', 'U', 'T', 'D', 'O', 'W', 'N', 0))
		return;
	smu_spinwait_simple(&cmd);
	for (;;)
		;
}


void smu_restart(void)
{
	struct smu_simple_cmd cmd;

	if (smu == NULL)
		return;

	if (smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 8, NULL, NULL,
			     'R', 'E', 'S', 'T', 'A', 'R', 'T', 0))
		return;
	smu_spinwait_simple(&cmd);
	for (;;)
		;
}


int smu_present(void)
{
	return smu != NULL;
}
EXPORT_SYMBOL(smu_present);


int __init smu_init (void)
{
	struct device_node *np;
	const u32 *data;
	int ret = 0;

        np = of_find_node_by_type(NULL, "smu");
        if (np == NULL)
		return -ENODEV;

	printk(KERN_INFO "SMU: Driver %s %s\n", VERSION, AUTHOR);

	/*
	 * SMU based G5s need some memory below 2Gb. Thankfully this is
	 * called at a time where memblock is still available.
	 */
	smu_cmdbuf_abs = memblock_phys_alloc_range(4096, 4096, 0, 0x80000000UL);
	if (smu_cmdbuf_abs == 0) {
		printk(KERN_ERR "SMU: Command buffer allocation failed !\n");
		ret = -EINVAL;
		goto fail_np;
	}

	smu = memblock_alloc(sizeof(struct smu_device), SMP_CACHE_BYTES);
	if (!smu)
		panic("%s: Failed to allocate %zu bytes\n", __func__,
		      sizeof(struct smu_device));

	spin_lock_init(&smu->lock);
	INIT_LIST_HEAD(&smu->cmd_list);
	INIT_LIST_HEAD(&smu->cmd_i2c_list);
	smu->of_node = np;
	smu->db_irq = 0;
	smu->msg_irq = 0;

	/* smu_cmdbuf_abs is in the low 2G of RAM, can be converted to a
	 * 32 bits value safely
	 */
	smu->cmd_buf_abs = (u32)smu_cmdbuf_abs;
	smu->cmd_buf = __va(smu_cmdbuf_abs);

	smu->db_node = of_find_node_by_name(NULL, "smu-doorbell");
	if (smu->db_node == NULL) {
		printk(KERN_ERR "SMU: Can't find doorbell GPIO !\n");
		ret = -ENXIO;
		goto fail_bootmem;
	}
	data = of_get_property(smu->db_node, "reg", NULL);
	if (data == NULL) {
		printk(KERN_ERR "SMU: Can't find doorbell GPIO address !\n");
		ret = -ENXIO;
		goto fail_db_node;
	}

	/* Current setup has one doorbell GPIO that does both doorbell
	 * and ack. GPIOs are at 0x50, best would be to find that out
	 * in the device-tree though.
	 */
	smu->doorbell = *data;
	if (smu->doorbell < 0x50)
		smu->doorbell += 0x50;

	/* Now look for the smu-interrupt GPIO */
	do {
		smu->msg_node = of_find_node_by_name(NULL, "smu-interrupt");
		if (smu->msg_node == NULL)
			break;
		data = of_get_property(smu->msg_node, "reg", NULL);
		if (data == NULL) {
			of_node_put(smu->msg_node);
			smu->msg_node = NULL;
			break;
		}
		smu->msg = *data;
		if (smu->msg < 0x50)
			smu->msg += 0x50;
	} while(0);

	/* Doorbell buffer is currently hard-coded, I didn't find a proper
	 * device-tree entry giving the address. Best would probably to use
	 * an offset for K2 base though, but let's do it that way for now.
	 */
	smu->db_buf = ioremap(0x8000860c, 0x1000);
	if (smu->db_buf == NULL) {
		printk(KERN_ERR "SMU: Can't map doorbell buffer pointer !\n");
		ret = -ENXIO;
		goto fail_msg_node;
	}

	/* U3 has an issue with NAP mode when issuing SMU commands */
	smu->broken_nap = pmac_get_uninorth_variant() < 4;
	if (smu->broken_nap)
		printk(KERN_INFO "SMU: using NAP mode workaround\n");

	sys_ctrler = SYS_CTRLER_SMU;
	return 0;

fail_msg_node:
	of_node_put(smu->msg_node);
fail_db_node:
	of_node_put(smu->db_node);
fail_bootmem:
	memblock_free(smu, sizeof(struct smu_device));
	smu = NULL;
fail_np:
	of_node_put(np);
	return ret;
}


static int smu_late_init(void)
{
	if (!smu)
		return 0;

	timer_setup(&smu->i2c_timer, smu_i2c_retry, 0);

	if (smu->db_node) {
		smu->db_irq = irq_of_parse_and_map(smu->db_node, 0);
		if (!smu->db_irq)
			printk(KERN_ERR "smu: failed to map irq for node %pOF\n",
			       smu->db_node);
	}
	if (smu->msg_node) {
		smu->msg_irq = irq_of_parse_and_map(smu->msg_node, 0);
		if (!smu->msg_irq)
			printk(KERN_ERR "smu: failed to map irq for node %pOF\n",
			       smu->msg_node);
	}

	/*
	 * Try to request the interrupts
	 */

	if (smu->db_irq) {
		if (request_irq(smu->db_irq, smu_db_intr,
				IRQF_SHARED, "SMU doorbell", smu) < 0) {
			printk(KERN_WARNING "SMU: can't "
			       "request interrupt %d\n",
			       smu->db_irq);
			smu->db_irq = 0;
		}
	}

	if (smu->msg_irq) {
		if (request_irq(smu->msg_irq, smu_msg_intr,
				IRQF_SHARED, "SMU message", smu) < 0) {
			printk(KERN_WARNING "SMU: can't "
			       "request interrupt %d\n",
			       smu->msg_irq);
			smu->msg_irq = 0;
		}
	}

	smu_irq_inited = 1;
	return 0;
}
/* This has to be before arch_initcall as the low i2c stuff relies on the
 * above having been done before we reach arch_initcalls
 */
core_initcall(smu_late_init);

/*
 * sysfs visibility
 */

static void smu_expose_childs(struct work_struct *unused)
{
	struct device_node *np;

	for_each_child_of_node(smu->of_node, np)
		if (of_device_is_compatible(np, "smu-sensors"))
			of_platform_device_create(np, "smu-sensors",
						  &smu->of_dev->dev);
}

static DECLARE_WORK(smu_expose_childs_work, smu_expose_childs);

static int smu_platform_probe(struct platform_device* dev)
{
	if (!smu)
		return -ENODEV;
	smu->of_dev = dev;

	/*
	 * Ok, we are matched, now expose all i2c busses. We have to defer
	 * that unfortunately or it would deadlock inside the device model
	 */
	schedule_work(&smu_expose_childs_work);

	return 0;
}

static const struct of_device_id smu_platform_match[] =
{
	{
		.type		= "smu",
	},
	{},
};

static struct platform_driver smu_of_platform_driver =
{
	.driver = {
		.name = "smu",
		.of_match_table = smu_platform_match,
	},
	.probe		= smu_platform_probe,
};

static int __init smu_init_sysfs(void)
{
	/*
	 * For now, we don't power manage machines with an SMU chip,
	 * I'm a bit too far from figuring out how that works with those
	 * new chipsets, but that will come back and bite us
	 */
	platform_driver_register(&smu_of_platform_driver);
	return 0;
}

device_initcall(smu_init_sysfs);

struct platform_device *smu_get_ofdev(void)
{
	if (!smu)
		return NULL;
	return smu->of_dev;
}

EXPORT_SYMBOL_GPL(smu_get_ofdev);

/*
 * i2c interface
 */

static void smu_i2c_complete_command(struct smu_i2c_cmd *cmd, int fail)
{
	void (*done)(struct smu_i2c_cmd *cmd, void *misc) = cmd->done;
	void *misc = cmd->misc;
	unsigned long flags;

	/* Check for read case */
	if (!fail && cmd->read) {
		if (cmd->pdata[0] < 1)
			fail = 1;
		else
			memcpy(cmd->info.data, &cmd->pdata[1],
			       cmd->info.datalen);
	}

	DPRINTK("SMU: completing, success: %d\n", !fail);

	/* Update status and mark no pending i2c command with lock
	 * held so nobody comes in while we dequeue an eventual
	 * pending next i2c command
	 */
	spin_lock_irqsave(&smu->lock, flags);
	smu->cmd_i2c_cur = NULL;
	wmb();
	cmd->status = fail ? -EIO : 0;

	/* Is there another i2c command waiting ? */
	if (!list_empty(&smu->cmd_i2c_list)) {
		struct smu_i2c_cmd *newcmd;

		/* Fetch it, new current, remove from list */
		newcmd = list_entry(smu->cmd_i2c_list.next,
				    struct smu_i2c_cmd, link);
		smu->cmd_i2c_cur = newcmd;
		list_del(&cmd->link);

		/* Queue with low level smu */
		list_add_tail(&cmd->scmd.link, &smu->cmd_list);
		if (smu->cmd_cur == NULL)
			smu_start_cmd();
	}
	spin_unlock_irqrestore(&smu->lock, flags);

	/* Call command completion handler if any */
	if (done)
		done(cmd, misc);

}


static void smu_i2c_retry(struct timer_list *unused)
{
	struct smu_i2c_cmd	*cmd = smu->cmd_i2c_cur;

	DPRINTK("SMU: i2c failure, requeuing...\n");

	/* requeue command simply by resetting reply_len */
	cmd->pdata[0] = 0xff;
	cmd->scmd.reply_len = sizeof(cmd->pdata);
	smu_queue_cmd(&cmd->scmd);
}


static void smu_i2c_low_completion(struct smu_cmd *scmd, void *misc)
{
	struct smu_i2c_cmd	*cmd = misc;
	int			fail = 0;

	DPRINTK("SMU: i2c compl. stage=%d status=%x pdata[0]=%x rlen: %x\n",
		cmd->stage, scmd->status, cmd->pdata[0], scmd->reply_len);

	/* Check for possible status */
	if (scmd->status < 0)
		fail = 1;
	else if (cmd->read) {
		if (cmd->stage == 0)
			fail = cmd->pdata[0] != 0;
		else
			fail = cmd->pdata[0] >= 0x80;
	} else {
		fail = cmd->pdata[0] != 0;
	}

	/* Handle failures by requeuing command, after 5ms interval
	 */
	if (fail && --cmd->retries > 0) {
		DPRINTK("SMU: i2c failure, starting timer...\n");
		BUG_ON(cmd != smu->cmd_i2c_cur);
		if (!smu_irq_inited) {
			mdelay(5);
			smu_i2c_retry(NULL);
			return;
		}
		mod_timer(&smu->i2c_timer, jiffies + msecs_to_jiffies(5));
		return;
	}

	/* If failure or stage 1, command is complete */
	if (fail || cmd->stage != 0) {
		smu_i2c_complete_command(cmd, fail);
		return;
	}

	DPRINTK("SMU: going to stage 1\n");

	/* Ok, initial command complete, now poll status */
	scmd->reply_buf = cmd->pdata;
	scmd->reply_len = sizeof(cmd->pdata);
	scmd->data_buf = cmd->pdata;
	scmd->data_len = 1;
	cmd->pdata[0] = 0;
	cmd->stage = 1;
	cmd->retries = 20;
	smu_queue_cmd(scmd);
}


int smu_queue_i2c(struct smu_i2c_cmd *cmd)
{
	unsigned long flags;

	if (smu == NULL)
		return -ENODEV;

	/* Fill most fields of scmd */
	cmd->scmd.cmd = SMU_CMD_I2C_COMMAND;
	cmd->scmd.done = smu_i2c_low_completion;
	cmd->scmd.misc = cmd;
	cmd->scmd.reply_buf = cmd->pdata;
	cmd->scmd.reply_len = sizeof(cmd->pdata);
	cmd->scmd.data_buf = (u8 *)(char *)&cmd->info;
	cmd->scmd.status = 1;
	cmd->stage = 0;
	cmd->pdata[0] = 0xff;
	cmd->retries = 20;
	cmd->status = 1;

	/* Check transfer type, sanitize some "info" fields
	 * based on transfer type and do more checking
	 */
	cmd->info.caddr = cmd->info.devaddr;
	cmd->read = cmd->info.devaddr & 0x01;
	switch(cmd->info.type) {
	case SMU_I2C_TRANSFER_SIMPLE:
		cmd->info.sublen = 0;
		memset(cmd->info.subaddr, 0, sizeof(cmd->info.subaddr));
		break;
	case SMU_I2C_TRANSFER_COMBINED:
		cmd->info.devaddr &= 0xfe;
		fallthrough;
	case SMU_I2C_TRANSFER_STDSUB:
		if (cmd->info.sublen > 3)
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}

	/* Finish setting up command based on transfer direction
	 */
	if (cmd->read) {
		if (cmd->info.datalen > SMU_I2C_READ_MAX)
			return -EINVAL;
		memset(cmd->info.data, 0xff, cmd->info.datalen);
		cmd->scmd.data_len = 9;
	} else {
		if (cmd->info.datalen > SMU_I2C_WRITE_MAX)
			return -EINVAL;
		cmd->scmd.data_len = 9 + cmd->info.datalen;
	}

	DPRINTK("SMU: i2c enqueuing command\n");
	DPRINTK("SMU:   %s, len=%d bus=%x addr=%x sub0=%x type=%x\n",
		cmd->read ? "read" : "write", cmd->info.datalen,
		cmd->info.bus, cmd->info.caddr,
		cmd->info.subaddr[0], cmd->info.type);


	/* Enqueue command in i2c list, and if empty, enqueue also in
	 * main command list
	 */
	spin_lock_irqsave(&smu->lock, flags);
	if (smu->cmd_i2c_cur == NULL) {
		smu->cmd_i2c_cur = cmd;
		list_add_tail(&cmd->scmd.link, &smu->cmd_list);
		if (smu->cmd_cur == NULL)
			smu_start_cmd();
	} else
		list_add_tail(&cmd->link, &smu->cmd_i2c_list);
	spin_unlock_irqrestore(&smu->lock, flags);

	return 0;
}

/*
 * Handling of "partitions"
 */

static int smu_read_datablock(u8 *dest, unsigned int addr, unsigned int len)
{
	DECLARE_COMPLETION_ONSTACK(comp);
	unsigned int chunk;
	struct smu_cmd cmd;
	int rc;
	u8 params[8];

	/* We currently use a chunk size of 0xe. We could check the
	 * SMU firmware version and use bigger sizes though
	 */
	chunk = 0xe;

	while (len) {
		unsigned int clen = min(len, chunk);

		cmd.cmd = SMU_CMD_MISC_ee_COMMAND;
		cmd.data_len = 7;
		cmd.data_buf = params;
		cmd.reply_len = chunk;
		cmd.reply_buf = dest;
		cmd.done = smu_done_complete;
		cmd.misc = &comp;
		params[0] = SMU_CMD_MISC_ee_GET_DATABLOCK_REC;
		params[1] = 0x4;
		*((u32 *)&params[2]) = addr;
		params[6] = clen;

		rc = smu_queue_cmd(&cmd);
		if (rc)
			return rc;
		wait_for_completion(&comp);
		if (cmd.status != 0)
			return rc;
		if (cmd.reply_len != clen) {
			printk(KERN_DEBUG "SMU: short read in "
			       "smu_read_datablock, got: %d, want: %d\n",
			       cmd.reply_len, clen);
			return -EIO;
		}
		len -= clen;
		addr += clen;
		dest += clen;
	}
	return 0;
}

static struct smu_sdbp_header *smu_create_sdb_partition(int id)
{
	DECLARE_COMPLETION_ONSTACK(comp);
	struct smu_simple_cmd cmd;
	unsigned int addr, len, tlen;
	struct smu_sdbp_header *hdr;
	struct property *prop;

	/* First query the partition info */
	DPRINTK("SMU: Query partition infos ... (irq=%d)\n", smu->db_irq);
	smu_queue_simple(&cmd, SMU_CMD_PARTITION_COMMAND, 2,
			 smu_done_complete, &comp,
			 SMU_CMD_PARTITION_LATEST, id);
	wait_for_completion(&comp);
	DPRINTK("SMU: done, status: %d, reply_len: %d\n",
		cmd.cmd.status, cmd.cmd.reply_len);

	/* Partition doesn't exist (or other error) */
	if (cmd.cmd.status != 0 || cmd.cmd.reply_len != 6)
		return NULL;

	/* Fetch address and length from reply */
	addr = *((u16 *)cmd.buffer);
	len = cmd.buffer[3] << 2;
	/* Calucluate total length to allocate, including the 17 bytes
	 * for "sdb-partition-XX" that we append at the end of the buffer
	 */
	tlen = sizeof(struct property) + len + 18;

	prop = kzalloc(tlen, GFP_KERNEL);
	if (prop == NULL)
		return NULL;
	hdr = (struct smu_sdbp_header *)(prop + 1);
	prop->name = ((char *)prop) + tlen - 18;
	sprintf(prop->name, "sdb-partition-%02x", id);
	prop->length = len;
	prop->value = hdr;
	prop->next = NULL;

	/* Read the datablock */
	if (smu_read_datablock((u8 *)hdr, addr, len)) {
		printk(KERN_DEBUG "SMU: datablock read failed while reading "
		       "partition %02x !\n", id);
		goto failure;
	}

	/* Got it, check a few things and create the property */
	if (hdr->id != id) {
		printk(KERN_DEBUG "SMU: Reading partition %02x and got "
		       "%02x !\n", id, hdr->id);
		goto failure;
	}
	if (of_add_property(smu->of_node, prop)) {
		printk(KERN_DEBUG "SMU: Failed creating sdb-partition-%02x "
		       "property !\n", id);
		goto failure;
	}

	return hdr;
 failure:
	kfree(prop);
	return NULL;
}

/* Note: Only allowed to return error code in pointers (using ERR_PTR)
 * when interruptible is 1
 */
static const struct smu_sdbp_header *__smu_get_sdb_partition(int id,
		unsigned int *size, int interruptible)
{
	char pname[32];
	const struct smu_sdbp_header *part;

	if (!smu)
		return NULL;

	sprintf(pname, "sdb-partition-%02x", id);

	DPRINTK("smu_get_sdb_partition(%02x)\n", id);

	if (interruptible) {
		int rc;
		rc = mutex_lock_interruptible(&smu_part_access);
		if (rc)
			return ERR_PTR(rc);
	} else
		mutex_lock(&smu_part_access);

	part = of_get_property(smu->of_node, pname, size);
	if (part == NULL) {
		DPRINTK("trying to extract from SMU ...\n");
		part = smu_create_sdb_partition(id);
		if (part != NULL && size)
			*size = part->len << 2;
	}
	mutex_unlock(&smu_part_access);
	return part;
}

const struct smu_sdbp_header *smu_get_sdb_partition(int id, unsigned int *size)
{
	return __smu_get_sdb_partition(id, size, 0);
}
EXPORT_SYMBOL(smu_get_sdb_partition);


/*
 * Userland driver interface
 */


static LIST_HEAD(smu_clist);
static DEFINE_SPINLOCK(smu_clist_lock);

enum smu_file_mode {
	smu_file_commands,
	smu_file_events,
	smu_file_closing
};

struct smu_private
{
	struct list_head	list;
	enum smu_file_mode	mode;
	int			busy;
	struct smu_cmd		cmd;
	spinlock_t		lock;
	wait_queue_head_t	wait;
	u8			buffer[SMU_MAX_DATA];
};


static int smu_open(struct inode *inode, struct file *file)
{
	struct smu_private *pp;
	unsigned long flags;

	pp = kzalloc(sizeof(struct smu_private), GFP_KERNEL);
	if (!pp)
		return -ENOMEM;
	spin_lock_init(&pp->lock);
	pp->mode = smu_file_commands;
	init_waitqueue_head(&pp->wait);

	mutex_lock(&smu_mutex);
	spin_lock_irqsave(&smu_clist_lock, flags);
	list_add(&pp->list, &smu_clist);
	spin_unlock_irqrestore(&smu_clist_lock, flags);
	file->private_data = pp;
	mutex_unlock(&smu_mutex);

	return 0;
}


static void smu_user_cmd_done(struct smu_cmd *cmd, void *misc)
{
	struct smu_private *pp = misc;

	wake_up_all(&pp->wait);
}


static ssize_t smu_write(struct file *file, const char __user *buf,
			 size_t count, loff_t *ppos)
{
	struct smu_private *pp = file->private_data;
	unsigned long flags;
	struct smu_user_cmd_hdr hdr;
	int rc = 0;

	if (pp->busy)
		return -EBUSY;
	else if (copy_from_user(&hdr, buf, sizeof(hdr)))
		return -EFAULT;
	else if (hdr.cmdtype == SMU_CMDTYPE_WANTS_EVENTS) {
		pp->mode = smu_file_events;
		return 0;
	} else if (hdr.cmdtype == SMU_CMDTYPE_GET_PARTITION) {
		const struct smu_sdbp_header *part;
		part = __smu_get_sdb_partition(hdr.cmd, NULL, 1);
		if (part == NULL)
			return -EINVAL;
		else if (IS_ERR(part))
			return PTR_ERR(part);
		return 0;
	} else if (hdr.cmdtype != SMU_CMDTYPE_SMU)
		return -EINVAL;
	else if (pp->mode != smu_file_commands)
		return -EBADFD;
	else if (hdr.data_len > SMU_MAX_DATA)
		return -EINVAL;

	spin_lock_irqsave(&pp->lock, flags);
	if (pp->busy) {
		spin_unlock_irqrestore(&pp->lock, flags);
		return -EBUSY;
	}
	pp->busy = 1;
	pp->cmd.status = 1;
	spin_unlock_irqrestore(&pp->lock, flags);

	if (copy_from_user(pp->buffer, buf + sizeof(hdr), hdr.data_len)) {
		pp->busy = 0;
		return -EFAULT;
	}

	pp->cmd.cmd = hdr.cmd;
	pp->cmd.data_len = hdr.data_len;
	pp->cmd.reply_len = SMU_MAX_DATA;
	pp->cmd.data_buf = pp->buffer;
	pp->cmd.reply_buf = pp->buffer;
	pp->cmd.done = smu_user_cmd_done;
	pp->cmd.misc = pp;
	rc = smu_queue_cmd(&pp->cmd);
	if (rc < 0)
		return rc;
	return count;
}


static ssize_t smu_read_command(struct file *file, struct smu_private *pp,
				char __user *buf, size_t count)
{
	DECLARE_WAITQUEUE(wait, current);
	struct smu_user_reply_hdr hdr;
	unsigned long flags;
	int size, rc = 0;

	if (!pp->busy)
		return 0;
	if (count < sizeof(struct smu_user_reply_hdr))
		return -EOVERFLOW;
	spin_lock_irqsave(&pp->lock, flags);
	if (pp->cmd.status == 1) {
		if (file->f_flags & O_NONBLOCK) {
			spin_unlock_irqrestore(&pp->lock, flags);
			return -EAGAIN;
		}
		add_wait_queue(&pp->wait, &wait);
		for (;;) {
			set_current_state(TASK_INTERRUPTIBLE);
			rc = 0;
			if (pp->cmd.status != 1)
				break;
			rc = -ERESTARTSYS;
			if (signal_pending(current))
				break;
			spin_unlock_irqrestore(&pp->lock, flags);
			schedule();
			spin_lock_irqsave(&pp->lock, flags);
		}
		set_current_state(TASK_RUNNING);
		remove_wait_queue(&pp->wait, &wait);
	}
	spin_unlock_irqrestore(&pp->lock, flags);
	if (rc)
		return rc;
	if (pp->cmd.status != 0)
		pp->cmd.reply_len = 0;
	size = sizeof(hdr) + pp->cmd.reply_len;
	if (count < size)
		size = count;
	rc = size;
	hdr.status = pp->cmd.status;
	hdr.reply_len = pp->cmd.reply_len;
	if (copy_to_user(buf, &hdr, sizeof(hdr)))
		return -EFAULT;
	size -= sizeof(hdr);
	if (size && copy_to_user(buf + sizeof(hdr), pp->buffer, size))
		return -EFAULT;
	pp->busy = 0;

	return rc;
}


static ssize_t smu_read_events(struct file *file, struct smu_private *pp,
			       char __user *buf, size_t count)
{
	/* Not implemented */
	msleep_interruptible(1000);
	return 0;
}


static ssize_t smu_read(struct file *file, char __user *buf,
			size_t count, loff_t *ppos)
{
	struct smu_private *pp = file->private_data;

	if (pp->mode == smu_file_commands)
		return smu_read_command(file, pp, buf, count);
	if (pp->mode == smu_file_events)
		return smu_read_events(file, pp, buf, count);

	return -EBADFD;
}

static __poll_t smu_fpoll(struct file *file, poll_table *wait)
{
	struct smu_private *pp = file->private_data;
	__poll_t mask = 0;
	unsigned long flags;

	if (!pp)
		return 0;

	if (pp->mode == smu_file_commands) {
		poll_wait(file, &pp->wait, wait);

		spin_lock_irqsave(&pp->lock, flags);
		if (pp->busy && pp->cmd.status != 1)
			mask |= EPOLLIN;
		spin_unlock_irqrestore(&pp->lock, flags);
	}
	if (pp->mode == smu_file_events) {
		/* Not yet implemented */
	}
	return mask;
}

static int smu_release(struct inode *inode, struct file *file)
{
	struct smu_private *pp = file->private_data;
	unsigned long flags;
	unsigned int busy;

	if (!pp)
		return 0;

	file->private_data = NULL;

	/* Mark file as closing to avoid races with new request */
	spin_lock_irqsave(&pp->lock, flags);
	pp->mode = smu_file_closing;
	busy = pp->busy;

	/* Wait for any pending request to complete */
	if (busy && pp->cmd.status == 1) {
		DECLARE_WAITQUEUE(wait, current);

		add_wait_queue(&pp->wait, &wait);
		for (;;) {
			set_current_state(TASK_UNINTERRUPTIBLE);
			if (pp->cmd.status != 1)
				break;
			spin_unlock_irqrestore(&pp->lock, flags);
			schedule();
			spin_lock_irqsave(&pp->lock, flags);
		}
		set_current_state(TASK_RUNNING);
		remove_wait_queue(&pp->wait, &wait);
	}
	spin_unlock_irqrestore(&pp->lock, flags);

	spin_lock_irqsave(&smu_clist_lock, flags);
	list_del(&pp->list);
	spin_unlock_irqrestore(&smu_clist_lock, flags);
	kfree(pp);

	return 0;
}


static const struct file_operations smu_device_fops = {
	.llseek		= no_llseek,
	.read		= smu_read,
	.write		= smu_write,
	.poll		= smu_fpoll,
	.open		= smu_open,
	.release	= smu_release,
};

static struct miscdevice pmu_device = {
	MISC_DYNAMIC_MINOR, "smu", &smu_device_fops
};

static int smu_device_init(void)
{
	if (!smu)
		return -ENODEV;
	if (misc_register(&pmu_device) < 0)
		printk(KERN_ERR "via-pmu: cannot register misc device.\n");
	return 0;
}
device_initcall(smu_device_init);