summaryrefslogtreecommitdiffstats
path: root/drivers/spi/spi_imx.c
blob: 3b4650ae6f1ab14acd070d9b87f0faa75c1e3ce2 (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
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
/*
 * drivers/spi/spi_imx.c
 *
 * Copyright (C) 2006 SWAPP
 *	Andrea Paterniani <a.paterniani@swapp-eng.it>
 *
 * Initial version inspired by:
 *	linux-2.6.17-rc3-mm1/drivers/spi/pxa2xx_spi.c
 *
 * 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.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/spi/spi.h>
#include <linux/workqueue.h>
#include <linux/delay.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/delay.h>

#include <asm/arch/hardware.h>
#include <asm/arch/imx-dma.h>
#include <asm/arch/spi_imx.h>

/*-------------------------------------------------------------------------*/
/* SPI Registers offsets from peripheral base address */
#define SPI_RXDATA		(0x00)
#define SPI_TXDATA		(0x04)
#define SPI_CONTROL		(0x08)
#define SPI_INT_STATUS		(0x0C)
#define SPI_TEST		(0x10)
#define SPI_PERIOD		(0x14)
#define SPI_DMA			(0x18)
#define SPI_RESET		(0x1C)

/* SPI Control Register Bit Fields & Masks */
#define SPI_CONTROL_BITCOUNT_MASK	(0xF)		/* Bit Count Mask */
#define SPI_CONTROL_BITCOUNT(n)		(((n) - 1) & SPI_CONTROL_BITCOUNT_MASK)
#define SPI_CONTROL_POL			(0x1 << 4)      /* Clock Polarity Mask */
#define SPI_CONTROL_POL_ACT_HIGH	(0x0 << 4)      /* Active high pol. (0=idle) */
#define SPI_CONTROL_POL_ACT_LOW		(0x1 << 4)      /* Active low pol. (1=idle) */
#define SPI_CONTROL_PHA			(0x1 << 5)      /* Clock Phase Mask */
#define SPI_CONTROL_PHA_0		(0x0 << 5)      /* Clock Phase 0 */
#define SPI_CONTROL_PHA_1		(0x1 << 5)      /* Clock Phase 1 */
#define SPI_CONTROL_SSCTL		(0x1 << 6)      /* /SS Waveform Select Mask */
#define SPI_CONTROL_SSCTL_0		(0x0 << 6)      /* Master: /SS stays low between SPI burst
							   Slave: RXFIFO advanced by BIT_COUNT */
#define SPI_CONTROL_SSCTL_1		(0x1 << 6)      /* Master: /SS insert pulse between SPI burst
							   Slave: RXFIFO advanced by /SS rising edge */
#define SPI_CONTROL_SSPOL		(0x1 << 7)      /* /SS Polarity Select Mask */
#define SPI_CONTROL_SSPOL_ACT_LOW	(0x0 << 7)      /* /SS Active low */
#define SPI_CONTROL_SSPOL_ACT_HIGH	(0x1 << 7)      /* /SS Active high */
#define SPI_CONTROL_XCH			(0x1 << 8)      /* Exchange */
#define SPI_CONTROL_SPIEN		(0x1 << 9)      /* SPI Module Enable */
#define SPI_CONTROL_MODE		(0x1 << 10)     /* SPI Mode Select Mask */
#define SPI_CONTROL_MODE_SLAVE		(0x0 << 10)     /* SPI Mode Slave */
#define SPI_CONTROL_MODE_MASTER		(0x1 << 10)     /* SPI Mode Master */
#define SPI_CONTROL_DRCTL		(0x3 << 11)     /* /SPI_RDY Control Mask */
#define SPI_CONTROL_DRCTL_0		(0x0 << 11)     /* Ignore /SPI_RDY */
#define SPI_CONTROL_DRCTL_1		(0x1 << 11)     /* /SPI_RDY falling edge triggers input */
#define SPI_CONTROL_DRCTL_2		(0x2 << 11)     /* /SPI_RDY active low level triggers input */
#define SPI_CONTROL_DATARATE		(0x7 << 13)     /* Data Rate Mask */
#define SPI_PERCLK2_DIV_MIN		(0)		/* PERCLK2:4 */
#define SPI_PERCLK2_DIV_MAX		(7)		/* PERCLK2:512 */
#define SPI_CONTROL_DATARATE_MIN	(SPI_PERCLK2_DIV_MAX << 13)
#define SPI_CONTROL_DATARATE_MAX	(SPI_PERCLK2_DIV_MIN << 13)
#define SPI_CONTROL_DATARATE_BAD	(SPI_CONTROL_DATARATE_MIN + 1)

/* SPI Interrupt/Status Register Bit Fields & Masks */
#define SPI_STATUS_TE	(0x1 << 0)	/* TXFIFO Empty Status */
#define SPI_STATUS_TH	(0x1 << 1)      /* TXFIFO Half Status */
#define SPI_STATUS_TF	(0x1 << 2)      /* TXFIFO Full Status */
#define SPI_STATUS_RR	(0x1 << 3)      /* RXFIFO Data Ready Status */
#define SPI_STATUS_RH	(0x1 << 4)      /* RXFIFO Half Status */
#define SPI_STATUS_RF	(0x1 << 5)      /* RXFIFO Full Status */
#define SPI_STATUS_RO	(0x1 << 6)      /* RXFIFO Overflow */
#define SPI_STATUS_BO	(0x1 << 7)      /* Bit Count Overflow */
#define SPI_STATUS	(0xFF)		/* SPI Status Mask */
#define SPI_INTEN_TE	(0x1 << 8)      /* TXFIFO Empty Interrupt Enable */
#define SPI_INTEN_TH	(0x1 << 9)      /* TXFIFO Half Interrupt Enable */
#define SPI_INTEN_TF	(0x1 << 10)     /* TXFIFO Full Interrupt Enable */
#define SPI_INTEN_RE	(0x1 << 11)     /* RXFIFO Data Ready Interrupt Enable */
#define SPI_INTEN_RH	(0x1 << 12)     /* RXFIFO Half Interrupt Enable */
#define SPI_INTEN_RF	(0x1 << 13)     /* RXFIFO Full Interrupt Enable */
#define SPI_INTEN_RO	(0x1 << 14)     /* RXFIFO Overflow Interrupt Enable */
#define SPI_INTEN_BO	(0x1 << 15)     /* Bit Count Overflow Interrupt Enable */
#define SPI_INTEN	(0xFF << 8)	/* SPI Interrupt Enable Mask */

/* SPI Test Register Bit Fields & Masks */
#define SPI_TEST_TXCNT		(0xF << 0)	/* TXFIFO Counter */
#define SPI_TEST_RXCNT_LSB	(4)		/* RXFIFO Counter LSB */
#define SPI_TEST_RXCNT		(0xF << 4)	/* RXFIFO Counter */
#define SPI_TEST_SSTATUS	(0xF << 8)	/* State Machine Status */
#define SPI_TEST_LBC		(0x1 << 14)	/* Loop Back Control */

/* SPI Period Register Bit Fields & Masks */
#define SPI_PERIOD_WAIT		(0x7FFF << 0)	/* Wait Between Transactions */
#define SPI_PERIOD_MAX_WAIT	(0x7FFF)	/* Max Wait Between
							Transactions */
#define SPI_PERIOD_CSRC		(0x1 << 15)	/* Period Clock Source Mask */
#define SPI_PERIOD_CSRC_BCLK	(0x0 << 15)	/* Period Clock Source is
							Bit Clock */
#define SPI_PERIOD_CSRC_32768	(0x1 << 15)	/* Period Clock Source is
							32.768 KHz Clock */

/* SPI DMA Register Bit Fields & Masks */
#define SPI_DMA_RHDMA	(0x1 << 4)	/* RXFIFO Half Status */
#define SPI_DMA_RFDMA	(0x1 << 5)      /* RXFIFO Full Status */
#define SPI_DMA_TEDMA	(0x1 << 6)      /* TXFIFO Empty Status */
#define SPI_DMA_THDMA	(0x1 << 7)      /* TXFIFO Half Status */
#define SPI_DMA_RHDEN	(0x1 << 12)	/* RXFIFO Half DMA Request Enable */
#define SPI_DMA_RFDEN	(0x1 << 13)     /* RXFIFO Full DMA Request Enable */
#define SPI_DMA_TEDEN	(0x1 << 14)     /* TXFIFO Empty DMA Request Enable */
#define SPI_DMA_THDEN	(0x1 << 15)     /* TXFIFO Half DMA Request Enable */

/* SPI Soft Reset Register Bit Fields & Masks */
#define SPI_RESET_START	(0x1)		/* Start */

/* Default SPI configuration values */
#define SPI_DEFAULT_CONTROL		\
(					\
	SPI_CONTROL_BITCOUNT(16) | 	\
	SPI_CONTROL_POL_ACT_HIGH |	\
	SPI_CONTROL_PHA_0 |		\
	SPI_CONTROL_SPIEN |		\
	SPI_CONTROL_SSCTL_1 |		\
	SPI_CONTROL_MODE_MASTER |	\
	SPI_CONTROL_DRCTL_0 |		\
	SPI_CONTROL_DATARATE_MIN	\
)
#define SPI_DEFAULT_ENABLE_LOOPBACK	(0)
#define SPI_DEFAULT_ENABLE_DMA		(0)
#define SPI_DEFAULT_PERIOD_WAIT		(8)
/*-------------------------------------------------------------------------*/


/*-------------------------------------------------------------------------*/
/* TX/RX SPI FIFO size */
#define SPI_FIFO_DEPTH			(8)
#define SPI_FIFO_BYTE_WIDTH		(2)
#define SPI_FIFO_OVERFLOW_MARGIN	(2)

/* DMA burst lenght for half full/empty request trigger */
#define SPI_DMA_BLR			(SPI_FIFO_DEPTH * SPI_FIFO_BYTE_WIDTH / 2)

/* Dummy char output to achieve reads.
   Choosing something different from all zeroes may help pattern recogition
   for oscilloscope analysis, but may break some drivers. */
#define SPI_DUMMY_u8			0
#define SPI_DUMMY_u16			((SPI_DUMMY_u8 << 8) | SPI_DUMMY_u8)
#define SPI_DUMMY_u32			((SPI_DUMMY_u16 << 16) | SPI_DUMMY_u16)

/**
 * Macro to change a u32 field:
 * @r : register to edit
 * @m : bit mask
 * @v : new value for the field correctly bit-alligned
*/
#define u32_EDIT(r, m, v)		r = (r & ~(m)) | (v)

/* Message state */
#define START_STATE			((void*)0)
#define RUNNING_STATE			((void*)1)
#define DONE_STATE			((void*)2)
#define ERROR_STATE			((void*)-1)

/* Queue state */
#define QUEUE_RUNNING			(0)
#define QUEUE_STOPPED			(1)

#define IS_DMA_ALIGNED(x) 		(((u32)(x) & 0x03) == 0)
/*-------------------------------------------------------------------------*/


/*-------------------------------------------------------------------------*/
/* Driver data structs */

/* Context */
struct driver_data {
	/* Driver model hookup */
	struct platform_device *pdev;

	/* SPI framework hookup */
	struct spi_master *master;

	/* IMX hookup */
	struct spi_imx_master *master_info;

	/* Memory resources and SPI regs virtual address */
	struct resource *ioarea;
	void __iomem *regs;

	/* SPI RX_DATA physical address */
	dma_addr_t rd_data_phys;

	/* Driver message queue */
	struct workqueue_struct	*workqueue;
	struct work_struct work;
	spinlock_t lock;
	struct list_head queue;
	int busy;
	int run;

	/* Message Transfer pump */
	struct tasklet_struct pump_transfers;

	/* Current message, transfer and state */
	struct spi_message *cur_msg;
	struct spi_transfer *cur_transfer;
	struct chip_data *cur_chip;

	/* Rd / Wr buffers pointers */
	size_t len;
	void *tx;
	void *tx_end;
	void *rx;
	void *rx_end;

	u8 rd_only;
	u8 n_bytes;
	int cs_change;

	/* Function pointers */
	irqreturn_t (*transfer_handler)(struct driver_data *drv_data);
	void (*cs_control)(u32 command);

	/* DMA setup */
	int rx_channel;
	int tx_channel;
	dma_addr_t rx_dma;
	dma_addr_t tx_dma;
	int rx_dma_needs_unmap;
	int tx_dma_needs_unmap;
	size_t tx_map_len;
	u32 dummy_dma_buf ____cacheline_aligned;
};

/* Runtime state */
struct chip_data {
	u32 control;
	u32 period;
	u32 test;

	u8 enable_dma:1;
	u8 bits_per_word;
	u8 n_bytes;
	u32 max_speed_hz;

	void (*cs_control)(u32 command);
};
/*-------------------------------------------------------------------------*/


static void pump_messages(struct work_struct *work);

static int flush(struct driver_data *drv_data)
{
	unsigned long limit = loops_per_jiffy << 1;
	void __iomem *regs = drv_data->regs;
	volatile u32 d;

	dev_dbg(&drv_data->pdev->dev, "flush\n");
	do {
		while (readl(regs + SPI_INT_STATUS) & SPI_STATUS_RR)
			d = readl(regs + SPI_RXDATA);
	} while ((readl(regs + SPI_CONTROL) & SPI_CONTROL_XCH) && limit--);

	return limit;
}

static void restore_state(struct driver_data *drv_data)
{
	void __iomem *regs = drv_data->regs;
	struct chip_data *chip = drv_data->cur_chip;

	/* Load chip registers */
	dev_dbg(&drv_data->pdev->dev,
		"restore_state\n"
		"    test    = 0x%08X\n"
		"    control = 0x%08X\n",
		chip->test,
		chip->control);
	writel(chip->test, regs + SPI_TEST);
	writel(chip->period, regs + SPI_PERIOD);
	writel(0, regs + SPI_INT_STATUS);
	writel(chip->control, regs + SPI_CONTROL);
}

static void null_cs_control(u32 command)
{
}

static inline u32 data_to_write(struct driver_data *drv_data)
{
	return ((u32)(drv_data->tx_end - drv_data->tx)) / drv_data->n_bytes;
}

static inline u32 data_to_read(struct driver_data *drv_data)
{
	return ((u32)(drv_data->rx_end - drv_data->rx)) / drv_data->n_bytes;
}

static int write(struct driver_data *drv_data)
{
	void __iomem *regs = drv_data->regs;
	void *tx = drv_data->tx;
	void *tx_end = drv_data->tx_end;
	u8 n_bytes = drv_data->n_bytes;
	u32 remaining_writes;
	u32 fifo_avail_space;
	u32 n;
	u16 d;

	/* Compute how many fifo writes to do */
	remaining_writes = (u32)(tx_end - tx) / n_bytes;
	fifo_avail_space = SPI_FIFO_DEPTH -
				(readl(regs + SPI_TEST) & SPI_TEST_TXCNT);
	if (drv_data->rx && (fifo_avail_space > SPI_FIFO_OVERFLOW_MARGIN))
		/* Fix misunderstood receive overflow */
		fifo_avail_space -= SPI_FIFO_OVERFLOW_MARGIN;
	n = min(remaining_writes, fifo_avail_space);

	dev_dbg(&drv_data->pdev->dev,
		"write type %s\n"
		"    remaining writes = %d\n"
		"    fifo avail space = %d\n"
		"    fifo writes      = %d\n",
		(n_bytes == 1) ? "u8" : "u16",
		remaining_writes,
		fifo_avail_space,
		n);

	if (n > 0) {
		/* Fill SPI TXFIFO */
		if (drv_data->rd_only) {
			tx += n * n_bytes;
			while (n--)
				writel(SPI_DUMMY_u16, regs + SPI_TXDATA);
		} else {
			if (n_bytes == 1) {
				while (n--) {
					d = *(u8*)tx;
					writel(d, regs + SPI_TXDATA);
					tx += 1;
				}
			} else {
				while (n--) {
					d = *(u16*)tx;
					writel(d, regs + SPI_TXDATA);
					tx += 2;
				}
			}
		}

		/* Trigger transfer */
		writel(readl(regs + SPI_CONTROL) | SPI_CONTROL_XCH,
			regs + SPI_CONTROL);

		/* Update tx pointer */
		drv_data->tx = tx;
	}

	return (tx >= tx_end);
}

static int read(struct driver_data *drv_data)
{
	void __iomem *regs = drv_data->regs;
	void *rx = drv_data->rx;
	void *rx_end = drv_data->rx_end;
	u8 n_bytes = drv_data->n_bytes;
	u32 remaining_reads;
	u32 fifo_rxcnt;
	u32 n;
	u16 d;

	/* Compute how many fifo reads to do */
	remaining_reads = (u32)(rx_end - rx) / n_bytes;
	fifo_rxcnt = (readl(regs + SPI_TEST) & SPI_TEST_RXCNT) >>
			SPI_TEST_RXCNT_LSB;
	n = min(remaining_reads, fifo_rxcnt);

	dev_dbg(&drv_data->pdev->dev,
		"read type %s\n"
		"    remaining reads = %d\n"
		"    fifo rx count   = %d\n"
		"    fifo reads      = %d\n",
		(n_bytes == 1) ? "u8" : "u16",
		remaining_reads,
		fifo_rxcnt,
		n);

	if (n > 0) {
		/* Read SPI RXFIFO */
		if (n_bytes == 1) {
			while (n--) {
				d = readl(regs + SPI_RXDATA);
				*((u8*)rx) = d;
				rx += 1;
			}
		} else {
			while (n--) {
				d = readl(regs + SPI_RXDATA);
				*((u16*)rx) = d;
				rx += 2;
			}
		}

		/* Update rx pointer */
		drv_data->rx = rx;
	}

	return (rx >= rx_end);
}

static void *next_transfer(struct driver_data *drv_data)
{
	struct spi_message *msg = drv_data->cur_msg;
	struct spi_transfer *trans = drv_data->cur_transfer;

	/* Move to next transfer */
	if (trans->transfer_list.next != &msg->transfers) {
		drv_data->cur_transfer =
			list_entry(trans->transfer_list.next,
					struct spi_transfer,
					transfer_list);
		return RUNNING_STATE;
	}

	return DONE_STATE;
}

static int map_dma_buffers(struct driver_data *drv_data)
{
	struct spi_message *msg;
	struct device *dev;
	void *buf;

	drv_data->rx_dma_needs_unmap = 0;
	drv_data->tx_dma_needs_unmap = 0;

	if (!drv_data->master_info->enable_dma ||
		!drv_data->cur_chip->enable_dma)
			return -1;

	msg = drv_data->cur_msg;
	dev = &msg->spi->dev;
	if (msg->is_dma_mapped) {
		if (drv_data->tx_dma)
			/* The caller provided at least dma and cpu virtual
			   address for write; pump_transfers() will consider the
			   transfer as write only if cpu rx virtual address is
			   NULL */
			return 0;

		if (drv_data->rx_dma) {
			/* The caller provided dma and cpu virtual address to
			   performe read only transfer -->
			   use drv_data->dummy_dma_buf for dummy writes to
			   achive reads */
			buf = &drv_data->dummy_dma_buf;
			drv_data->tx_map_len = sizeof(drv_data->dummy_dma_buf);
			drv_data->tx_dma = dma_map_single(dev,
							buf,
							drv_data->tx_map_len,
							DMA_TO_DEVICE);
			if (dma_mapping_error(drv_data->tx_dma))
				return -1;

			drv_data->tx_dma_needs_unmap = 1;

			/* Flags transfer as rd_only for pump_transfers() DMA
			   regs programming (should be redundant) */
			drv_data->tx = NULL;

			return 0;
		}
	}

	if (!IS_DMA_ALIGNED(drv_data->rx) || !IS_DMA_ALIGNED(drv_data->tx))
		return -1;

	/* NULL rx means write-only transfer and no map needed
	   since rx DMA will not be used */
	if (drv_data->rx) {
		buf = drv_data->rx;
		drv_data->rx_dma = dma_map_single(
					dev,
					buf,
					drv_data->len,
					DMA_FROM_DEVICE);
		if (dma_mapping_error(drv_data->rx_dma))
			return -1;
		drv_data->rx_dma_needs_unmap = 1;
	}

	if (drv_data->tx == NULL) {
		/* Read only message --> use drv_data->dummy_dma_buf for dummy
		   writes to achive reads */
		buf = &drv_data->dummy_dma_buf;
		drv_data->tx_map_len = sizeof(drv_data->dummy_dma_buf);
	} else {
		buf = drv_data->tx;
		drv_data->tx_map_len = drv_data->len;
	}
	drv_data->tx_dma = dma_map_single(dev,
					buf,
					drv_data->tx_map_len,
					DMA_TO_DEVICE);
	if (dma_mapping_error(drv_data->tx_dma)) {
		if (drv_data->rx_dma) {
			dma_unmap_single(dev,
					drv_data->rx_dma,
					drv_data->len,
					DMA_FROM_DEVICE);
			drv_data->rx_dma_needs_unmap = 0;
		}
		return -1;
	}
	drv_data->tx_dma_needs_unmap = 1;

	return 0;
}

static void unmap_dma_buffers(struct driver_data *drv_data)
{
	struct spi_message *msg = drv_data->cur_msg;
	struct device *dev = &msg->spi->dev;

	if (drv_data->rx_dma_needs_unmap) {
		dma_unmap_single(dev,
				drv_data->rx_dma,
				drv_data->len,
				DMA_FROM_DEVICE);
		drv_data->rx_dma_needs_unmap = 0;
	}
	if (drv_data->tx_dma_needs_unmap) {
		dma_unmap_single(dev,
				drv_data->tx_dma,
				drv_data->tx_map_len,
				DMA_TO_DEVICE);
		drv_data->tx_dma_needs_unmap = 0;
	}
}

/* Caller already set message->status (dma is already blocked) */
static void giveback(struct spi_message *message, struct driver_data *drv_data)
{
	void __iomem *regs = drv_data->regs;

	/* Bring SPI to sleep; restore_state() and pump_transfer()
	   will do new setup */
	writel(0, regs + SPI_INT_STATUS);
	writel(0, regs + SPI_DMA);

	drv_data->cs_control(SPI_CS_DEASSERT);

	message->state = NULL;
	if (message->complete)
		message->complete(message->context);

	drv_data->cur_msg = NULL;
	drv_data->cur_transfer = NULL;
	drv_data->cur_chip = NULL;
	queue_work(drv_data->workqueue, &drv_data->work);
}

static void dma_err_handler(int channel, void *data, int errcode)
{
	struct driver_data *drv_data = data;
	struct spi_message *msg = drv_data->cur_msg;

	dev_dbg(&drv_data->pdev->dev, "dma_err_handler\n");

	/* Disable both rx and tx dma channels */
	imx_dma_disable(drv_data->rx_channel);
	imx_dma_disable(drv_data->tx_channel);

	if (flush(drv_data) == 0)
		dev_err(&drv_data->pdev->dev,
				"dma_err_handler - flush failed\n");

	unmap_dma_buffers(drv_data);

	msg->state = ERROR_STATE;
	tasklet_schedule(&drv_data->pump_transfers);
}

static void dma_tx_handler(int channel, void *data)
{
	struct driver_data *drv_data = data;

	dev_dbg(&drv_data->pdev->dev, "dma_tx_handler\n");

	imx_dma_disable(channel);

	/* Now waits for TX FIFO empty */
	writel(readl(drv_data->regs + SPI_INT_STATUS) | SPI_INTEN_TE,
			drv_data->regs + SPI_INT_STATUS);
}

static irqreturn_t dma_transfer(struct driver_data *drv_data)
{
	u32 status;
	struct spi_message *msg = drv_data->cur_msg;
	void __iomem *regs = drv_data->regs;
	unsigned long limit;

	status = readl(regs + SPI_INT_STATUS);

	if ((status & SPI_INTEN_RO) && (status & SPI_STATUS_RO)) {
		writel(status & ~SPI_INTEN, regs + SPI_INT_STATUS);

		imx_dma_disable(drv_data->rx_channel);
		unmap_dma_buffers(drv_data);

		if (flush(drv_data) == 0)
			dev_err(&drv_data->pdev->dev,
				"dma_transfer - flush failed\n");

		dev_warn(&drv_data->pdev->dev,
				"dma_transfer - fifo overun\n");

		msg->state = ERROR_STATE;
		tasklet_schedule(&drv_data->pump_transfers);

		return IRQ_HANDLED;
	}

	if (status & SPI_STATUS_TE) {
		writel(status & ~SPI_INTEN_TE, regs + SPI_INT_STATUS);

		if (drv_data->rx) {
			/* Wait end of transfer before read trailing data */
			limit = loops_per_jiffy << 1;
			while ((readl(regs + SPI_CONTROL) & SPI_CONTROL_XCH) &&
					limit--);

			if (limit == 0)
				dev_err(&drv_data->pdev->dev,
					"dma_transfer - end of tx failed\n");
			else
				dev_dbg(&drv_data->pdev->dev,
					"dma_transfer - end of tx\n");

			imx_dma_disable(drv_data->rx_channel);
			unmap_dma_buffers(drv_data);

			/* Calculate number of trailing data and read them */
			dev_dbg(&drv_data->pdev->dev,
				"dma_transfer - test = 0x%08X\n",
				readl(regs + SPI_TEST));
			drv_data->rx = drv_data->rx_end -
					((readl(regs + SPI_TEST) &
					SPI_TEST_RXCNT) >>
					SPI_TEST_RXCNT_LSB)*drv_data->n_bytes;
			read(drv_data);
		} else {
			/* Write only transfer */
			unmap_dma_buffers(drv_data);

			if (flush(drv_data) == 0)
				dev_err(&drv_data->pdev->dev,
					"dma_transfer - flush failed\n");
		}

		/* End of transfer, update total byte transfered */
		msg->actual_length += drv_data->len;

		/* Release chip select if requested, transfer delays are
		   handled in pump_transfers() */
		if (drv_data->cs_change)
			drv_data->cs_control(SPI_CS_DEASSERT);

		/* Move to next transfer */
		msg->state = next_transfer(drv_data);

		/* Schedule transfer tasklet */
		tasklet_schedule(&drv_data->pump_transfers);

		return IRQ_HANDLED;
	}

	/* Opps problem detected */
	return IRQ_NONE;
}

static irqreturn_t interrupt_wronly_transfer(struct driver_data *drv_data)
{
	struct spi_message *msg = drv_data->cur_msg;
	void __iomem *regs = drv_data->regs;
	u32 status;
	irqreturn_t handled = IRQ_NONE;

	status = readl(regs + SPI_INT_STATUS);

	while (status & SPI_STATUS_TH) {
		dev_dbg(&drv_data->pdev->dev,
			"interrupt_wronly_transfer - status = 0x%08X\n", status);

		/* Pump data */
		if (write(drv_data)) {
			writel(readl(regs + SPI_INT_STATUS) & ~SPI_INTEN,
				regs + SPI_INT_STATUS);

			dev_dbg(&drv_data->pdev->dev,
				"interrupt_wronly_transfer - end of tx\n");

			if (flush(drv_data) == 0)
				dev_err(&drv_data->pdev->dev,
					"interrupt_wronly_transfer - "
					"flush failed\n");

			/* End of transfer, update total byte transfered */
			msg->actual_length += drv_data->len;

			/* Release chip select if requested, transfer delays are
			   handled in pump_transfers */
			if (drv_data->cs_change)
				drv_data->cs_control(SPI_CS_DEASSERT);

			/* Move to next transfer */
			msg->state = next_transfer(drv_data);

			/* Schedule transfer tasklet */
			tasklet_schedule(&drv_data->pump_transfers);

			return IRQ_HANDLED;
		}

		status = readl(regs + SPI_INT_STATUS);

		/* We did something */
		handled = IRQ_HANDLED;
	}

	return handled;
}

static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
{
	struct spi_message *msg = drv_data->cur_msg;
	void __iomem *regs = drv_data->regs;
	u32 status;
	irqreturn_t handled = IRQ_NONE;
	unsigned long limit;

	status = readl(regs + SPI_INT_STATUS);

	while (status & (SPI_STATUS_TH | SPI_STATUS_RO)) {
		dev_dbg(&drv_data->pdev->dev,
			"interrupt_transfer - status = 0x%08X\n", status);

		if (status & SPI_STATUS_RO) {
			writel(readl(regs + SPI_INT_STATUS) & ~SPI_INTEN,
				regs + SPI_INT_STATUS);

			dev_warn(&drv_data->pdev->dev,
				"interrupt_transfer - fifo overun\n"
				"    data not yet written = %d\n"
				"    data not yet read    = %d\n",
				data_to_write(drv_data),
				data_to_read(drv_data));

			if (flush(drv_data) == 0)
				dev_err(&drv_data->pdev->dev,
					"interrupt_transfer - flush failed\n");

			msg->state = ERROR_STATE;
			tasklet_schedule(&drv_data->pump_transfers);

			return IRQ_HANDLED;
		}

		/* Pump data */
		read(drv_data);
		if (write(drv_data)) {
			writel(readl(regs + SPI_INT_STATUS) & ~SPI_INTEN,
				regs + SPI_INT_STATUS);

			dev_dbg(&drv_data->pdev->dev,
				"interrupt_transfer - end of tx\n");

			/* Read trailing bytes */
			limit = loops_per_jiffy << 1;
			while ((read(drv_data) == 0) && limit--);

			if (limit == 0)
				dev_err(&drv_data->pdev->dev,
					"interrupt_transfer - "
					"trailing byte read failed\n");
			else
				dev_dbg(&drv_data->pdev->dev,
					"interrupt_transfer - end of rx\n");

			/* End of transfer, update total byte transfered */
			msg->actual_length += drv_data->len;

			/* Release chip select if requested, transfer delays are
			   handled in pump_transfers */
			if (drv_data->cs_change)
				drv_data->cs_control(SPI_CS_DEASSERT);

			/* Move to next transfer */
			msg->state = next_transfer(drv_data);

			/* Schedule transfer tasklet */
			tasklet_schedule(&drv_data->pump_transfers);

			return IRQ_HANDLED;
		}

		status = readl(regs + SPI_INT_STATUS);

		/* We did something */
		handled = IRQ_HANDLED;
	}

	return handled;
}

static irqreturn_t spi_int(int irq, void *dev_id)
{
	struct driver_data *drv_data = (struct driver_data *)dev_id;

	if (!drv_data->cur_msg) {
		dev_err(&drv_data->pdev->dev,
			"spi_int - bad message state\n");
		/* Never fail */
		return IRQ_HANDLED;
	}

	return drv_data->transfer_handler(drv_data);
}

static inline u32 spi_speed_hz(u32 data_rate)
{
	return imx_get_perclk2() / (4 << ((data_rate) >> 13));
}

static u32 spi_data_rate(u32 speed_hz)
{
	u32 div;
	u32 quantized_hz = imx_get_perclk2() >> 2;

	for (div = SPI_PERCLK2_DIV_MIN;
		div <= SPI_PERCLK2_DIV_MAX;
		div++, quantized_hz >>= 1) {
			if (quantized_hz <= speed_hz)
				/* Max available speed LEQ required speed */
				return div << 13;
	}
	return SPI_CONTROL_DATARATE_BAD;
}

static void pump_transfers(unsigned long data)
{
	struct driver_data *drv_data = (struct driver_data *)data;
	struct spi_message *message;
	struct spi_transfer *transfer, *previous;
	struct chip_data *chip;
	void __iomem *regs;
	u32 tmp, control;

	dev_dbg(&drv_data->pdev->dev, "pump_transfer\n");

	message = drv_data->cur_msg;

	/* Handle for abort */
	if (message->state == ERROR_STATE) {
		message->status = -EIO;
		giveback(message, drv_data);
		return;
	}

	/* Handle end of message */
	if (message->state == DONE_STATE) {
		message->status = 0;
		giveback(message, drv_data);
		return;
	}

	chip = drv_data->cur_chip;

	/* Delay if requested at end of transfer*/
	transfer = drv_data->cur_transfer;
	if (message->state == RUNNING_STATE) {
		previous = list_entry(transfer->transfer_list.prev,
					struct spi_transfer,
					transfer_list);
		if (previous->delay_usecs)
			udelay(previous->delay_usecs);
	} else {
		/* START_STATE */
		message->state = RUNNING_STATE;
		drv_data->cs_control = chip->cs_control;
	}

	transfer = drv_data->cur_transfer;
	drv_data->tx = (void *)transfer->tx_buf;
	drv_data->tx_end = drv_data->tx + transfer->len;
	drv_data->rx = transfer->rx_buf;
	drv_data->rx_end = drv_data->rx + transfer->len;
	drv_data->rx_dma = transfer->rx_dma;
	drv_data->tx_dma = transfer->tx_dma;
	drv_data->len = transfer->len;
	drv_data->cs_change = transfer->cs_change;
	drv_data->rd_only = (drv_data->tx == NULL);

	regs = drv_data->regs;
	control = readl(regs + SPI_CONTROL);

	/* Bits per word setup */
	tmp = transfer->bits_per_word;
	if (tmp == 0) {
		/* Use device setup */
		tmp = chip->bits_per_word;
		drv_data->n_bytes = chip->n_bytes;
	} else
		/* Use per-transfer setup */
		drv_data->n_bytes = (tmp <= 8) ? 1 : 2;
	u32_EDIT(control, SPI_CONTROL_BITCOUNT_MASK, tmp - 1);

	/* Speed setup (surely valid because already checked) */
	tmp = transfer->speed_hz;
	if (tmp == 0)
		tmp = chip->max_speed_hz;
	tmp = spi_data_rate(tmp);
	u32_EDIT(control, SPI_CONTROL_DATARATE, tmp);

	writel(control, regs + SPI_CONTROL);

	/* Assert device chip-select */
	drv_data->cs_control(SPI_CS_ASSERT);

	/* DMA cannot read/write SPI FIFOs other than 16 bits at a time; hence
	   if bits_per_word is less or equal 8 PIO transfers are performed.
	   Moreover DMA is convinient for transfer length bigger than FIFOs
	   byte size. */
	if ((drv_data->n_bytes == 2) &&
		(drv_data->len > SPI_FIFO_DEPTH*SPI_FIFO_BYTE_WIDTH) &&
		(map_dma_buffers(drv_data) == 0)) {
		dev_dbg(&drv_data->pdev->dev,
			"pump dma transfer\n"
			"    tx      = %p\n"
			"    tx_dma  = %08X\n"
			"    rx      = %p\n"
			"    rx_dma  = %08X\n"
			"    len     = %d\n",
			drv_data->tx,
			(unsigned int)drv_data->tx_dma,
			drv_data->rx,
			(unsigned int)drv_data->rx_dma,
			drv_data->len);

		/* Ensure we have the correct interrupt handler */
		drv_data->transfer_handler = dma_transfer;

		/* Trigger transfer */
		writel(readl(regs + SPI_CONTROL) | SPI_CONTROL_XCH,
			regs + SPI_CONTROL);

		/* Setup tx DMA */
		if (drv_data->tx)
			/* Linear source address */
			CCR(drv_data->tx_channel) =
				CCR_DMOD_FIFO |
				CCR_SMOD_LINEAR |
				CCR_SSIZ_32 | CCR_DSIZ_16 |
				CCR_REN;
		else
			/* Read only transfer -> fixed source address for
			   dummy write to achive read */
			CCR(drv_data->tx_channel) =
				CCR_DMOD_FIFO |
				CCR_SMOD_FIFO |
				CCR_SSIZ_32 | CCR_DSIZ_16 |
				CCR_REN;

		imx_dma_setup_single(
			drv_data->tx_channel,
			drv_data->tx_dma,
			drv_data->len,
			drv_data->rd_data_phys + 4,
			DMA_MODE_WRITE);

		if (drv_data->rx) {
			/* Setup rx DMA for linear destination address */
			CCR(drv_data->rx_channel) =
				CCR_DMOD_LINEAR |
				CCR_SMOD_FIFO |
				CCR_DSIZ_32 | CCR_SSIZ_16 |
				CCR_REN;
			imx_dma_setup_single(
				drv_data->rx_channel,
				drv_data->rx_dma,
				drv_data->len,
				drv_data->rd_data_phys,
				DMA_MODE_READ);
			imx_dma_enable(drv_data->rx_channel);

			/* Enable SPI interrupt */
			writel(SPI_INTEN_RO, regs + SPI_INT_STATUS);

			/* Set SPI to request DMA service on both
			   Rx and Tx half fifo watermark */
			writel(SPI_DMA_RHDEN | SPI_DMA_THDEN, regs + SPI_DMA);
		} else
			/* Write only access -> set SPI to request DMA
			   service on Tx half fifo watermark */
			writel(SPI_DMA_THDEN, regs + SPI_DMA);

		imx_dma_enable(drv_data->tx_channel);
	} else {
		dev_dbg(&drv_data->pdev->dev,
			"pump pio transfer\n"
			"    tx      = %p\n"
			"    rx      = %p\n"
			"    len     = %d\n",
			drv_data->tx,
			drv_data->rx,
			drv_data->len);

		/* Ensure we have the correct interrupt handler	*/
		if (drv_data->rx)
			drv_data->transfer_handler = interrupt_transfer;
		else
			drv_data->transfer_handler = interrupt_wronly_transfer;

		/* Enable SPI interrupt */
		if (drv_data->rx)
			writel(SPI_INTEN_TH | SPI_INTEN_RO,
				regs + SPI_INT_STATUS);
		else
			writel(SPI_INTEN_TH, regs + SPI_INT_STATUS);
	}
}

static void pump_messages(struct work_struct *work)
{
	struct driver_data *drv_data =
				container_of(work, struct driver_data, work);
	unsigned long flags;

	/* Lock queue and check for queue work */
	spin_lock_irqsave(&drv_data->lock, flags);
	if (list_empty(&drv_data->queue) || drv_data->run == QUEUE_STOPPED) {
		drv_data->busy = 0;
		spin_unlock_irqrestore(&drv_data->lock, flags);
		return;
	}

	/* Make sure we are not already running a message */
	if (drv_data->cur_msg) {
		spin_unlock_irqrestore(&drv_data->lock, flags);
		return;
	}

	/* Extract head of queue */
	drv_data->cur_msg = list_entry(drv_data->queue.next,
					struct spi_message, queue);
	list_del_init(&drv_data->cur_msg->queue);
	drv_data->busy = 1;
	spin_unlock_irqrestore(&drv_data->lock, flags);

	/* Initial message state */
	drv_data->cur_msg->state = START_STATE;
	drv_data->cur_transfer = list_entry(drv_data->cur_msg->transfers.next,
						struct spi_transfer,
						transfer_list);

	/* Setup the SPI using the per chip configuration */
	drv_data->cur_chip = spi_get_ctldata(drv_data->cur_msg->spi);
	restore_state(drv_data);

	/* Mark as busy and launch transfers */
	tasklet_schedule(&drv_data->pump_transfers);
}

static int transfer(struct spi_device *spi, struct spi_message *msg)
{
	struct driver_data *drv_data = spi_master_get_devdata(spi->master);
	u32 min_speed_hz, max_speed_hz, tmp;
	struct spi_transfer *trans;
	unsigned long flags;

	msg->actual_length = 0;

	/* Per transfer setup check */
	min_speed_hz = spi_speed_hz(SPI_CONTROL_DATARATE_MIN);
	max_speed_hz = spi->max_speed_hz;
	list_for_each_entry(trans, &msg->transfers, transfer_list) {
		tmp = trans->bits_per_word;
		if (tmp > 16) {
			dev_err(&drv_data->pdev->dev,
				"message rejected : "
				"invalid transfer bits_per_word (%d bits)\n",
				tmp);
			goto msg_rejected;
		}
		tmp = trans->speed_hz;
		if (tmp) {
			if (tmp < min_speed_hz) {
				dev_err(&drv_data->pdev->dev,
					"message rejected : "
					"device min speed (%d Hz) exceeds "
					"required transfer speed (%d Hz)\n",
					min_speed_hz,
					tmp);
				goto msg_rejected;
			} else if (tmp > max_speed_hz) {
				dev_err(&drv_data->pdev->dev,
					"message rejected : "
					"transfer speed (%d Hz) exceeds "
					"device max speed (%d Hz)\n",
					tmp,
					max_speed_hz);
				goto msg_rejected;
			}
		}
	}

	/* Message accepted */
	msg->status = -EINPROGRESS;
	msg->state = START_STATE;

	spin_lock_irqsave(&drv_data->lock, flags);
	if (drv_data->run == QUEUE_STOPPED) {
		spin_unlock_irqrestore(&drv_data->lock, flags);
		return -ESHUTDOWN;
	}

	list_add_tail(&msg->queue, &drv_data->queue);
	if (drv_data->run == QUEUE_RUNNING && !drv_data->busy)
		queue_work(drv_data->workqueue, &drv_data->work);

	spin_unlock_irqrestore(&drv_data->lock, flags);
	return 0;

msg_rejected:
	/* Message rejected and not queued */
	msg->status = -EINVAL;
	msg->state = ERROR_STATE;
	if (msg->complete)
		msg->complete(msg->context);
	return -EINVAL;
}

/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)

/* On first setup bad values must free chip_data memory since will cause
   spi_new_device to fail. Bad value setup from protocol driver are simply not
   applied and notified to the calling driver. */
static int setup(struct spi_device *spi)
{
	struct spi_imx_chip *chip_info;
	struct chip_data *chip;
	int first_setup = 0;
	u32 tmp;
	int status = 0;

	if (spi->mode & ~MODEBITS) {
		dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
			spi->mode & ~MODEBITS);
		return -EINVAL;
	}

	/* Get controller data */
	chip_info = spi->controller_data;

	/* Get controller_state */
	chip = spi_get_ctldata(spi);
	if (chip == NULL) {
		first_setup = 1;

		chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
		if (!chip) {
			dev_err(&spi->dev,
				"setup - cannot allocate controller state");
			return -ENOMEM;
		}
		chip->control = SPI_DEFAULT_CONTROL;

		if (chip_info == NULL) {
			/* spi_board_info.controller_data not is supplied */
			chip_info = kzalloc(sizeof(struct spi_imx_chip),
						GFP_KERNEL);
			if (!chip_info) {
				dev_err(&spi->dev,
					"setup - "
					"cannot allocate controller data");
				status = -ENOMEM;
				goto err_first_setup;
			}
			/* Set controller data default value */
			chip_info->enable_loopback =
						SPI_DEFAULT_ENABLE_LOOPBACK;
			chip_info->enable_dma = SPI_DEFAULT_ENABLE_DMA;
			chip_info->ins_ss_pulse = 1;
			chip_info->bclk_wait = SPI_DEFAULT_PERIOD_WAIT;
			chip_info->cs_control = null_cs_control;
		}
	}

	/* Now set controller state based on controller data */

	if (first_setup) {
		/* SPI loopback */
		if (chip_info->enable_loopback)
			chip->test = SPI_TEST_LBC;
		else
			chip->test = 0;

		/* SPI dma driven */
		chip->enable_dma = chip_info->enable_dma;

		/* SPI /SS pulse between spi burst */
		if (chip_info->ins_ss_pulse)
			u32_EDIT(chip->control,
				SPI_CONTROL_SSCTL, SPI_CONTROL_SSCTL_1);
		else
			u32_EDIT(chip->control,
				SPI_CONTROL_SSCTL, SPI_CONTROL_SSCTL_0);

		/* SPI bclk waits between each bits_per_word spi burst */
		if (chip_info->bclk_wait > SPI_PERIOD_MAX_WAIT) {
			dev_err(&spi->dev,
				"setup - "
				"bclk_wait exceeds max allowed (%d)\n",
				SPI_PERIOD_MAX_WAIT);
			goto err_first_setup;
		}
		chip->period = SPI_PERIOD_CSRC_BCLK |
				(chip_info->bclk_wait & SPI_PERIOD_WAIT);
	}

	/* SPI mode */
	tmp = spi->mode;
	if (tmp & SPI_CS_HIGH) {
		u32_EDIT(chip->control,
				SPI_CONTROL_SSPOL, SPI_CONTROL_SSPOL_ACT_HIGH);
	}
	switch (tmp & SPI_MODE_3) {
	case SPI_MODE_0:
		tmp = 0;
		break;
	case SPI_MODE_1:
		tmp = SPI_CONTROL_PHA_1;
		break;
	case SPI_MODE_2:
		tmp = SPI_CONTROL_POL_ACT_LOW;
		break;
	default:
		/* SPI_MODE_3 */
		tmp = SPI_CONTROL_PHA_1 | SPI_CONTROL_POL_ACT_LOW;
		break;
	}
	u32_EDIT(chip->control, SPI_CONTROL_POL | SPI_CONTROL_PHA, tmp);

	/* SPI word width */
	tmp = spi->bits_per_word;
	if (tmp == 0) {
		tmp = 8;
		spi->bits_per_word = 8;
	} else if (tmp > 16) {
		status = -EINVAL;
		dev_err(&spi->dev,
			"setup - "
			"invalid bits_per_word (%d)\n",
			tmp);
		if (first_setup)
			goto err_first_setup;
		else {
			/* Undo setup using chip as backup copy */
			tmp = chip->bits_per_word;
			spi->bits_per_word = tmp;
		}
	}
	chip->bits_per_word = tmp;
	u32_EDIT(chip->control, SPI_CONTROL_BITCOUNT_MASK, tmp - 1);
	chip->n_bytes = (tmp <= 8) ? 1 : 2;

	/* SPI datarate */
	tmp = spi_data_rate(spi->max_speed_hz);
	if (tmp == SPI_CONTROL_DATARATE_BAD) {
		status = -EINVAL;
		dev_err(&spi->dev,
			"setup - "
			"HW min speed (%d Hz) exceeds required "
			"max speed (%d Hz)\n",
			spi_speed_hz(SPI_CONTROL_DATARATE_MIN),
			spi->max_speed_hz);
		if (first_setup)
			goto err_first_setup;
		else
			/* Undo setup using chip as backup copy */
			spi->max_speed_hz = chip->max_speed_hz;
	} else {
		u32_EDIT(chip->control, SPI_CONTROL_DATARATE, tmp);
		/* Actual rounded max_speed_hz */
		tmp = spi_speed_hz(tmp);
		spi->max_speed_hz = tmp;
		chip->max_speed_hz = tmp;
	}

	/* SPI chip-select management */
	if (chip_info->cs_control)
		chip->cs_control = chip_info->cs_control;
	else
		chip->cs_control = null_cs_control;

	/* Save controller_state */
	spi_set_ctldata(spi, chip);

	/* Summary */
	dev_dbg(&spi->dev,
		"setup succeded\n"
		"    loopback enable   = %s\n"
		"    dma enable        = %s\n"
		"    insert /ss pulse  = %s\n"
		"    period wait       = %d\n"
		"    mode              = %d\n"
		"    bits per word     = %d\n"
		"    min speed         = %d Hz\n"
		"    rounded max speed = %d Hz\n",
		chip->test & SPI_TEST_LBC ? "Yes" : "No",
		chip->enable_dma ? "Yes" : "No",
		chip->control & SPI_CONTROL_SSCTL ? "Yes" : "No",
		chip->period & SPI_PERIOD_WAIT,
		spi->mode,
		spi->bits_per_word,
		spi_speed_hz(SPI_CONTROL_DATARATE_MIN),
		spi->max_speed_hz);
	return status;

err_first_setup:
	kfree(chip);
	return status;
}

static void cleanup(struct spi_device *spi)
{
	kfree(spi_get_ctldata(spi));
}

static int __init init_queue(struct driver_data *drv_data)
{
	INIT_LIST_HEAD(&drv_data->queue);
	spin_lock_init(&drv_data->lock);

	drv_data->run = QUEUE_STOPPED;
	drv_data->busy = 0;

	tasklet_init(&drv_data->pump_transfers,
			pump_transfers,	(unsigned long)drv_data);

	INIT_WORK(&drv_data->work, pump_messages);
	drv_data->workqueue = create_singlethread_workqueue(
					drv_data->master->dev.parent->bus_id);
	if (drv_data->workqueue == NULL)
		return -EBUSY;

	return 0;
}

static int start_queue(struct driver_data *drv_data)
{
	unsigned long flags;

	spin_lock_irqsave(&drv_data->lock, flags);

	if (drv_data->run == QUEUE_RUNNING || drv_data->busy) {
		spin_unlock_irqrestore(&drv_data->lock, flags);
		return -EBUSY;
	}

	drv_data->run = QUEUE_RUNNING;
	drv_data->cur_msg = NULL;
	drv_data->cur_transfer = NULL;
	drv_data->cur_chip = NULL;
	spin_unlock_irqrestore(&drv_data->lock, flags);

	queue_work(drv_data->workqueue, &drv_data->work);

	return 0;
}

static int stop_queue(struct driver_data *drv_data)
{
	unsigned long flags;
	unsigned limit = 500;
	int status = 0;

	spin_lock_irqsave(&drv_data->lock, flags);

	/* This is a bit lame, but is optimized for the common execution path.
	 * A wait_queue on the drv_data->busy could be used, but then the common
	 * execution path (pump_messages) would be required to call wake_up or
	 * friends on every SPI message. Do this instead */
	drv_data->run = QUEUE_STOPPED;
	while (!list_empty(&drv_data->queue) && drv_data->busy && limit--) {
		spin_unlock_irqrestore(&drv_data->lock, flags);
		msleep(10);
		spin_lock_irqsave(&drv_data->lock, flags);
	}

	if (!list_empty(&drv_data->queue) || drv_data->busy)
		status = -EBUSY;

	spin_unlock_irqrestore(&drv_data->lock, flags);

	return status;
}

static int destroy_queue(struct driver_data *drv_data)
{
	int status;

	status = stop_queue(drv_data);
	if (status != 0)
		return status;

	if (drv_data->workqueue)
		destroy_workqueue(drv_data->workqueue);

	return 0;
}

static int __init spi_imx_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct spi_imx_master *platform_info;
	struct spi_master *master;
	struct driver_data *drv_data = NULL;
	struct resource *res;
	int irq, status = 0;

	platform_info = dev->platform_data;
	if (platform_info == NULL) {
		dev_err(&pdev->dev, "probe - no platform data supplied\n");
		status = -ENODEV;
		goto err_no_pdata;
	}

	/* Allocate master with space for drv_data */
	master = spi_alloc_master(dev, sizeof(struct driver_data));
	if (!master) {
		dev_err(&pdev->dev, "probe - cannot alloc spi_master\n");
		status = -ENOMEM;
		goto err_no_mem;
	}
	drv_data = spi_master_get_devdata(master);
	drv_data->master = master;
	drv_data->master_info = platform_info;
	drv_data->pdev = pdev;

	master->bus_num = pdev->id;
	master->num_chipselect = platform_info->num_chipselect;
	master->cleanup = cleanup;
	master->setup = setup;
	master->transfer = transfer;

	drv_data->dummy_dma_buf = SPI_DUMMY_u32;

	/* Find and map resources */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&pdev->dev, "probe - MEM resources not defined\n");
		status = -ENODEV;
		goto err_no_iores;
	}
	drv_data->ioarea = request_mem_region(res->start,
						res->end - res->start + 1,
						pdev->name);
	if (drv_data->ioarea == NULL) {
		dev_err(&pdev->dev, "probe - cannot reserve region\n");
		status = -ENXIO;
		goto err_no_iores;
	}
	drv_data->regs = ioremap(res->start, res->end - res->start + 1);
	if (drv_data->regs == NULL) {
		dev_err(&pdev->dev, "probe - cannot map IO\n");
		status = -ENXIO;
		goto err_no_iomap;
	}
	drv_data->rd_data_phys = (dma_addr_t)res->start;

	/* Attach to IRQ */
	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "probe - IRQ resource not defined\n");
		status = -ENODEV;
		goto err_no_irqres;
	}
	status = request_irq(irq, spi_int, IRQF_DISABLED, dev->bus_id, drv_data);
	if (status < 0) {
		dev_err(&pdev->dev, "probe - cannot get IRQ (%d)\n", status);
		goto err_no_irqres;
	}

	/* Setup DMA if requested */
	drv_data->tx_channel = -1;
	drv_data->rx_channel = -1;
	if (platform_info->enable_dma) {
		/* Get rx DMA channel */
		status = imx_dma_request_by_prio(&drv_data->rx_channel,
			"spi_imx_rx", DMA_PRIO_HIGH);
		if (status < 0) {
			dev_err(dev,
				"probe - problem (%d) requesting rx channel\n",
				status);
			goto err_no_rxdma;
		} else
			imx_dma_setup_handlers(drv_data->rx_channel, NULL,
						dma_err_handler, drv_data);

		/* Get tx DMA channel */
		status = imx_dma_request_by_prio(&drv_data->tx_channel,
						"spi_imx_tx", DMA_PRIO_MEDIUM);
		if (status < 0) {
			dev_err(dev,
				"probe - problem (%d) requesting tx channel\n",
				status);
			imx_dma_free(drv_data->rx_channel);
			goto err_no_txdma;
		} else
			imx_dma_setup_handlers(drv_data->tx_channel,
						dma_tx_handler, dma_err_handler,
						drv_data);

		/* Set request source and burst length for allocated channels */
		switch (drv_data->pdev->id) {
		case 1:
			/* Using SPI1 */
			RSSR(drv_data->rx_channel) = DMA_REQ_SPI1_R;
			RSSR(drv_data->tx_channel) = DMA_REQ_SPI1_T;
			break;
		case 2:
			/* Using SPI2 */
			RSSR(drv_data->rx_channel) = DMA_REQ_SPI2_R;
			RSSR(drv_data->tx_channel) = DMA_REQ_SPI2_T;
			break;
		default:
			dev_err(dev, "probe - bad SPI Id\n");
			imx_dma_free(drv_data->rx_channel);
			imx_dma_free(drv_data->tx_channel);
			status = -ENODEV;
			goto err_no_devid;
		}
		BLR(drv_data->rx_channel) = SPI_DMA_BLR;
		BLR(drv_data->tx_channel) = SPI_DMA_BLR;
	}

	/* Load default SPI configuration */
	writel(SPI_RESET_START, drv_data->regs + SPI_RESET);
	writel(0, drv_data->regs + SPI_RESET);
	writel(SPI_DEFAULT_CONTROL, drv_data->regs + SPI_CONTROL);

	/* Initial and start queue */
	status = init_queue(drv_data);
	if (status != 0) {
		dev_err(&pdev->dev, "probe - problem initializing queue\n");
		goto err_init_queue;
	}
	status = start_queue(drv_data);
	if (status != 0) {
		dev_err(&pdev->dev, "probe - problem starting queue\n");
		goto err_start_queue;
	}

	/* Register with the SPI framework */
	platform_set_drvdata(pdev, drv_data);
	status = spi_register_master(master);
	if (status != 0) {
		dev_err(&pdev->dev, "probe - problem registering spi master\n");
		goto err_spi_register;
	}

	dev_dbg(dev, "probe succeded\n");
	return 0;

err_init_queue:
err_start_queue:
err_spi_register:
	destroy_queue(drv_data);

err_no_rxdma:
err_no_txdma:
err_no_devid:
	free_irq(irq, drv_data);

err_no_irqres:
	iounmap(drv_data->regs);

err_no_iomap:
	release_resource(drv_data->ioarea);
	kfree(drv_data->ioarea);

err_no_iores:
	spi_master_put(master);

err_no_pdata:
err_no_mem:
	return status;
}

static int __exit spi_imx_remove(struct platform_device *pdev)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);
	int irq;
	int status = 0;

	if (!drv_data)
		return 0;

	tasklet_kill(&drv_data->pump_transfers);

	/* Remove the queue */
	status = destroy_queue(drv_data);
	if (status != 0) {
		dev_err(&pdev->dev, "queue remove failed (%d)\n", status);
		return status;
	}

	/* Reset SPI */
	writel(SPI_RESET_START, drv_data->regs + SPI_RESET);
	writel(0, drv_data->regs + SPI_RESET);

	/* Release DMA */
	if (drv_data->master_info->enable_dma) {
		RSSR(drv_data->rx_channel) = 0;
		RSSR(drv_data->tx_channel) = 0;
		imx_dma_free(drv_data->tx_channel);
		imx_dma_free(drv_data->rx_channel);
	}

	/* Release IRQ */
	irq = platform_get_irq(pdev, 0);
	if (irq >= 0)
		free_irq(irq, drv_data);

	/* Release map resources */
	iounmap(drv_data->regs);
	release_resource(drv_data->ioarea);
	kfree(drv_data->ioarea);

	/* Disconnect from the SPI framework */
	spi_unregister_master(drv_data->master);
	spi_master_put(drv_data->master);

	/* Prevent double remove */
	platform_set_drvdata(pdev, NULL);

	dev_dbg(&pdev->dev, "remove succeded\n");

	return 0;
}

static void spi_imx_shutdown(struct platform_device *pdev)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);

	/* Reset SPI */
	writel(SPI_RESET_START, drv_data->regs + SPI_RESET);
	writel(0, drv_data->regs + SPI_RESET);

	dev_dbg(&pdev->dev, "shutdown succeded\n");
}

#ifdef CONFIG_PM
static int suspend_devices(struct device *dev, void *pm_message)
{
	pm_message_t *state = pm_message;

	if (dev->power.power_state.event != state->event) {
		dev_warn(dev, "pm state does not match request\n");
		return -1;
	}

	return 0;
}

static int spi_imx_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);
	int status = 0;

	status = stop_queue(drv_data);
	if (status != 0) {
		dev_warn(&pdev->dev, "suspend cannot stop queue\n");
		return status;
	}

	dev_dbg(&pdev->dev, "suspended\n");

	return 0;
}

static int spi_imx_resume(struct platform_device *pdev)
{
	struct driver_data *drv_data = platform_get_drvdata(pdev);
	int status = 0;

	/* Start the queue running */
	status = start_queue(drv_data);
	if (status != 0)
		dev_err(&pdev->dev, "problem starting queue (%d)\n", status);
	else
		dev_dbg(&pdev->dev, "resumed\n");

	return status;
}
#else
#define spi_imx_suspend NULL
#define spi_imx_resume NULL
#endif /* CONFIG_PM */

static struct platform_driver driver = {
	.driver = {
		.name = "spi_imx",
		.bus = &platform_bus_type,
		.owner = THIS_MODULE,
	},
	.remove = __exit_p(spi_imx_remove),
	.shutdown = spi_imx_shutdown,
	.suspend = spi_imx_suspend,
	.resume = spi_imx_resume,
};

static int __init spi_imx_init(void)
{
	return platform_driver_probe(&driver, spi_imx_probe);
}
module_init(spi_imx_init);

static void __exit spi_imx_exit(void)
{
	platform_driver_unregister(&driver);
}
module_exit(spi_imx_exit);

MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>");
MODULE_DESCRIPTION("iMX SPI Contoller Driver");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud