summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/i915/intel_lrc.c
blob: 424e6219778712dcaf0e7c5c1ae7c51709fce6ba (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
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
/*
 * Copyright © 2014 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Ben Widawsky <ben@bwidawsk.net>
 *    Michel Thierry <michel.thierry@intel.com>
 *    Thomas Daniel <thomas.daniel@intel.com>
 *    Oscar Mateo <oscar.mateo@intel.com>
 *
 */

/**
 * DOC: Logical Rings, Logical Ring Contexts and Execlists
 *
 * Motivation:
 * GEN8 brings an expansion of the HW contexts: "Logical Ring Contexts".
 * These expanded contexts enable a number of new abilities, especially
 * "Execlists" (also implemented in this file).
 *
 * One of the main differences with the legacy HW contexts is that logical
 * ring contexts incorporate many more things to the context's state, like
 * PDPs or ringbuffer control registers:
 *
 * The reason why PDPs are included in the context is straightforward: as
 * PPGTTs (per-process GTTs) are actually per-context, having the PDPs
 * contained there mean you don't need to do a ppgtt->switch_mm yourself,
 * instead, the GPU will do it for you on the context switch.
 *
 * But, what about the ringbuffer control registers (head, tail, etc..)?
 * shouldn't we just need a set of those per engine command streamer? This is
 * where the name "Logical Rings" starts to make sense: by virtualizing the
 * rings, the engine cs shifts to a new "ring buffer" with every context
 * switch. When you want to submit a workload to the GPU you: A) choose your
 * context, B) find its appropriate virtualized ring, C) write commands to it
 * and then, finally, D) tell the GPU to switch to that context.
 *
 * Instead of the legacy MI_SET_CONTEXT, the way you tell the GPU to switch
 * to a contexts is via a context execution list, ergo "Execlists".
 *
 * LRC implementation:
 * Regarding the creation of contexts, we have:
 *
 * - One global default context.
 * - One local default context for each opened fd.
 * - One local extra context for each context create ioctl call.
 *
 * Now that ringbuffers belong per-context (and not per-engine, like before)
 * and that contexts are uniquely tied to a given engine (and not reusable,
 * like before) we need:
 *
 * - One ringbuffer per-engine inside each context.
 * - One backing object per-engine inside each context.
 *
 * The global default context starts its life with these new objects fully
 * allocated and populated. The local default context for each opened fd is
 * more complex, because we don't know at creation time which engine is going
 * to use them. To handle this, we have implemented a deferred creation of LR
 * contexts:
 *
 * The local context starts its life as a hollow or blank holder, that only
 * gets populated for a given engine once we receive an execbuffer. If later
 * on we receive another execbuffer ioctl for the same context but a different
 * engine, we allocate/populate a new ringbuffer and context backing object and
 * so on.
 *
 * Finally, regarding local contexts created using the ioctl call: as they are
 * only allowed with the render ring, we can allocate & populate them right
 * away (no need to defer anything, at least for now).
 *
 * Execlists implementation:
 * Execlists are the new method by which, on gen8+ hardware, workloads are
 * submitted for execution (as opposed to the legacy, ringbuffer-based, method).
 * This method works as follows:
 *
 * When a request is committed, its commands (the BB start and any leading or
 * trailing commands, like the seqno breadcrumbs) are placed in the ringbuffer
 * for the appropriate context. The tail pointer in the hardware context is not
 * updated at this time, but instead, kept by the driver in the ringbuffer
 * structure. A structure representing this request is added to a request queue
 * for the appropriate engine: this structure contains a copy of the context's
 * tail after the request was written to the ring buffer and a pointer to the
 * context itself.
 *
 * If the engine's request queue was empty before the request was added, the
 * queue is processed immediately. Otherwise the queue will be processed during
 * a context switch interrupt. In any case, elements on the queue will get sent
 * (in pairs) to the GPU's ExecLists Submit Port (ELSP, for short) with a
 * globally unique 20-bits submission ID.
 *
 * When execution of a request completes, the GPU updates the context status
 * buffer with a context complete event and generates a context switch interrupt.
 * During the interrupt handling, the driver examines the events in the buffer:
 * for each context complete event, if the announced ID matches that on the head
 * of the request queue, then that request is retired and removed from the queue.
 *
 * After processing, if any requests were retired and the queue is not empty
 * then a new execution list can be submitted. The two requests at the front of
 * the queue are next to be submitted but since a context may not occur twice in
 * an execution list, if subsequent requests have the same ID as the first then
 * the two requests must be combined. This is done simply by discarding requests
 * at the head of the queue until either only one requests is left (in which case
 * we use a NULL second context) or the first two requests have unique IDs.
 *
 * By always executing the first two requests in the queue the driver ensures
 * that the GPU is kept as busy as possible. In the case where a single context
 * completes but a second context is still executing, the request for this second
 * context will be at the head of the queue when we remove the first one. This
 * request will then be resubmitted along with a new request for a different context,
 * which will cause the hardware to continue executing the second request and queue
 * the new request (the GPU detects the condition of a context getting preempted
 * with the same context and optimizes the context switch flow by not doing
 * preemption, but just sampling the new tail pointer).
 *
 */

#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"

#define GEN9_LR_CONTEXT_RENDER_SIZE (22 * PAGE_SIZE)
#define GEN8_LR_CONTEXT_RENDER_SIZE (20 * PAGE_SIZE)
#define GEN8_LR_CONTEXT_OTHER_SIZE (2 * PAGE_SIZE)

#define RING_EXECLIST_QFULL		(1 << 0x2)
#define RING_EXECLIST1_VALID		(1 << 0x3)
#define RING_EXECLIST0_VALID		(1 << 0x4)
#define RING_EXECLIST_ACTIVE_STATUS	(3 << 0xE)
#define RING_EXECLIST1_ACTIVE		(1 << 0x11)
#define RING_EXECLIST0_ACTIVE		(1 << 0x12)

#define GEN8_CTX_STATUS_IDLE_ACTIVE	(1 << 0)
#define GEN8_CTX_STATUS_PREEMPTED	(1 << 1)
#define GEN8_CTX_STATUS_ELEMENT_SWITCH	(1 << 2)
#define GEN8_CTX_STATUS_ACTIVE_IDLE	(1 << 3)
#define GEN8_CTX_STATUS_COMPLETE	(1 << 4)
#define GEN8_CTX_STATUS_LITE_RESTORE	(1 << 15)

#define CTX_LRI_HEADER_0		0x01
#define CTX_CONTEXT_CONTROL		0x02
#define CTX_RING_HEAD			0x04
#define CTX_RING_TAIL			0x06
#define CTX_RING_BUFFER_START		0x08
#define CTX_RING_BUFFER_CONTROL		0x0a
#define CTX_BB_HEAD_U			0x0c
#define CTX_BB_HEAD_L			0x0e
#define CTX_BB_STATE			0x10
#define CTX_SECOND_BB_HEAD_U		0x12
#define CTX_SECOND_BB_HEAD_L		0x14
#define CTX_SECOND_BB_STATE		0x16
#define CTX_BB_PER_CTX_PTR		0x18
#define CTX_RCS_INDIRECT_CTX		0x1a
#define CTX_RCS_INDIRECT_CTX_OFFSET	0x1c
#define CTX_LRI_HEADER_1		0x21
#define CTX_CTX_TIMESTAMP		0x22
#define CTX_PDP3_UDW			0x24
#define CTX_PDP3_LDW			0x26
#define CTX_PDP2_UDW			0x28
#define CTX_PDP2_LDW			0x2a
#define CTX_PDP1_UDW			0x2c
#define CTX_PDP1_LDW			0x2e
#define CTX_PDP0_UDW			0x30
#define CTX_PDP0_LDW			0x32
#define CTX_LRI_HEADER_2		0x41
#define CTX_R_PWR_CLK_STATE		0x42
#define CTX_GPGPU_CSR_BASE_ADDRESS	0x44

#define GEN8_CTX_VALID (1<<0)
#define GEN8_CTX_FORCE_PD_RESTORE (1<<1)
#define GEN8_CTX_FORCE_RESTORE (1<<2)
#define GEN8_CTX_L3LLC_COHERENT (1<<5)
#define GEN8_CTX_PRIVILEGE (1<<8)
enum {
	ADVANCED_CONTEXT = 0,
	LEGACY_CONTEXT,
	ADVANCED_AD_CONTEXT,
	LEGACY_64B_CONTEXT
};
#define GEN8_CTX_MODE_SHIFT 3
enum {
	FAULT_AND_HANG = 0,
	FAULT_AND_HALT, /* Debug only */
	FAULT_AND_STREAM,
	FAULT_AND_CONTINUE /* Unsupported */
};
#define GEN8_CTX_ID_SHIFT 32

static int intel_lr_context_pin(struct intel_engine_cs *ring,
		struct intel_context *ctx);

/**
 * intel_sanitize_enable_execlists() - sanitize i915.enable_execlists
 * @dev: DRM device.
 * @enable_execlists: value of i915.enable_execlists module parameter.
 *
 * Only certain platforms support Execlists (the prerequisites being
 * support for Logical Ring Contexts and Aliasing PPGTT or better).
 *
 * Return: 1 if Execlists is supported and has to be enabled.
 */
int intel_sanitize_enable_execlists(struct drm_device *dev, int enable_execlists)
{
	WARN_ON(i915.enable_ppgtt == -1);

	if (INTEL_INFO(dev)->gen >= 9)
		return 1;

	if (enable_execlists == 0)
		return 0;

	if (HAS_LOGICAL_RING_CONTEXTS(dev) && USES_PPGTT(dev) &&
	    i915.use_mmio_flip >= 0)
		return 1;

	return 0;
}

/**
 * intel_execlists_ctx_id() - get the Execlists Context ID
 * @ctx_obj: Logical Ring Context backing object.
 *
 * Do not confuse with ctx->id! Unfortunately we have a name overload
 * here: the old context ID we pass to userspace as a handler so that
 * they can refer to a context, and the new context ID we pass to the
 * ELSP so that the GPU can inform us of the context status via
 * interrupts.
 *
 * Return: 20-bits globally unique context ID.
 */
u32 intel_execlists_ctx_id(struct drm_i915_gem_object *ctx_obj)
{
	u32 lrca = i915_gem_obj_ggtt_offset(ctx_obj);

	/* LRCA is required to be 4K aligned so the more significant 20 bits
	 * are globally unique */
	return lrca >> 12;
}

static uint64_t execlists_ctx_descriptor(struct intel_engine_cs *ring,
					 struct drm_i915_gem_object *ctx_obj)
{
	struct drm_device *dev = ring->dev;
	uint64_t desc;
	uint64_t lrca = i915_gem_obj_ggtt_offset(ctx_obj);

	WARN_ON(lrca & 0xFFFFFFFF00000FFFULL);

	desc = GEN8_CTX_VALID;
	desc |= LEGACY_CONTEXT << GEN8_CTX_MODE_SHIFT;
	desc |= GEN8_CTX_L3LLC_COHERENT;
	desc |= GEN8_CTX_PRIVILEGE;
	desc |= lrca;
	desc |= (u64)intel_execlists_ctx_id(ctx_obj) << GEN8_CTX_ID_SHIFT;

	/* TODO: WaDisableLiteRestore when we start using semaphore
	 * signalling between Command Streamers */
	/* desc |= GEN8_CTX_FORCE_RESTORE; */

	/* WaEnableForceRestoreInCtxtDescForVCS:skl */
	if (IS_GEN9(dev) &&
	    INTEL_REVID(dev) <= SKL_REVID_B0 &&
	    (ring->id == BCS || ring->id == VCS ||
	    ring->id == VECS || ring->id == VCS2))
		desc |= GEN8_CTX_FORCE_RESTORE;

	return desc;
}

static void execlists_elsp_write(struct intel_engine_cs *ring,
				 struct drm_i915_gem_object *ctx_obj0,
				 struct drm_i915_gem_object *ctx_obj1)
{
	struct drm_device *dev = ring->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	uint64_t temp = 0;
	uint32_t desc[4];

	/* XXX: You must always write both descriptors in the order below. */
	if (ctx_obj1)
		temp = execlists_ctx_descriptor(ring, ctx_obj1);
	else
		temp = 0;
	desc[1] = (u32)(temp >> 32);
	desc[0] = (u32)temp;

	temp = execlists_ctx_descriptor(ring, ctx_obj0);
	desc[3] = (u32)(temp >> 32);
	desc[2] = (u32)temp;

	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
	I915_WRITE(RING_ELSP(ring), desc[1]);
	I915_WRITE(RING_ELSP(ring), desc[0]);
	I915_WRITE(RING_ELSP(ring), desc[3]);

	/* The context is automatically loaded after the following */
	I915_WRITE(RING_ELSP(ring), desc[2]);

	/* ELSP is a wo register, so use another nearby reg for posting instead */
	POSTING_READ(RING_EXECLIST_STATUS(ring));
	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
}

static int execlists_update_context(struct drm_i915_gem_object *ctx_obj,
				    struct drm_i915_gem_object *ring_obj,
				    u32 tail)
{
	struct page *page;
	uint32_t *reg_state;

	page = i915_gem_object_get_page(ctx_obj, 1);
	reg_state = kmap_atomic(page);

	reg_state[CTX_RING_TAIL+1] = tail;
	reg_state[CTX_RING_BUFFER_START+1] = i915_gem_obj_ggtt_offset(ring_obj);

	kunmap_atomic(reg_state);

	return 0;
}

static void execlists_submit_contexts(struct intel_engine_cs *ring,
				      struct intel_context *to0, u32 tail0,
				      struct intel_context *to1, u32 tail1)
{
	struct drm_i915_gem_object *ctx_obj0 = to0->engine[ring->id].state;
	struct intel_ringbuffer *ringbuf0 = to0->engine[ring->id].ringbuf;
	struct drm_i915_gem_object *ctx_obj1 = NULL;
	struct intel_ringbuffer *ringbuf1 = NULL;

	BUG_ON(!ctx_obj0);
	WARN_ON(!i915_gem_obj_is_pinned(ctx_obj0));
	WARN_ON(!i915_gem_obj_is_pinned(ringbuf0->obj));

	execlists_update_context(ctx_obj0, ringbuf0->obj, tail0);

	if (to1) {
		ringbuf1 = to1->engine[ring->id].ringbuf;
		ctx_obj1 = to1->engine[ring->id].state;
		BUG_ON(!ctx_obj1);
		WARN_ON(!i915_gem_obj_is_pinned(ctx_obj1));
		WARN_ON(!i915_gem_obj_is_pinned(ringbuf1->obj));

		execlists_update_context(ctx_obj1, ringbuf1->obj, tail1);
	}

	execlists_elsp_write(ring, ctx_obj0, ctx_obj1);
}

static void execlists_context_unqueue(struct intel_engine_cs *ring)
{
	struct drm_i915_gem_request *req0 = NULL, *req1 = NULL;
	struct drm_i915_gem_request *cursor = NULL, *tmp = NULL;

	assert_spin_locked(&ring->execlist_lock);

	if (list_empty(&ring->execlist_queue))
		return;

	/* Try to read in pairs */
	list_for_each_entry_safe(cursor, tmp, &ring->execlist_queue,
				 execlist_link) {
		if (!req0) {
			req0 = cursor;
		} else if (req0->ctx == cursor->ctx) {
			/* Same ctx: ignore first request, as second request
			 * will update tail past first request's workload */
			cursor->elsp_submitted = req0->elsp_submitted;
			list_del(&req0->execlist_link);
			list_add_tail(&req0->execlist_link,
				&ring->execlist_retired_req_list);
			req0 = cursor;
		} else {
			req1 = cursor;
			break;
		}
	}

	if (IS_GEN8(ring->dev) || IS_GEN9(ring->dev)) {
		/*
		 * WaIdleLiteRestore: make sure we never cause a lite
		 * restore with HEAD==TAIL
		 */
		if (req0 && req0->elsp_submitted) {
			/*
			 * Apply the wa NOOPS to prevent ring:HEAD == req:TAIL
			 * as we resubmit the request. See gen8_emit_request()
			 * for where we prepare the padding after the end of the
			 * request.
			 */
			struct intel_ringbuffer *ringbuf;

			ringbuf = req0->ctx->engine[ring->id].ringbuf;
			req0->tail += 8;
			req0->tail &= ringbuf->size - 1;
		}
	}

	WARN_ON(req1 && req1->elsp_submitted);

	execlists_submit_contexts(ring, req0->ctx, req0->tail,
				  req1 ? req1->ctx : NULL,
				  req1 ? req1->tail : 0);

	req0->elsp_submitted++;
	if (req1)
		req1->elsp_submitted++;
}

static bool execlists_check_remove_request(struct intel_engine_cs *ring,
					   u32 request_id)
{
	struct drm_i915_gem_request *head_req;

	assert_spin_locked(&ring->execlist_lock);

	head_req = list_first_entry_or_null(&ring->execlist_queue,
					    struct drm_i915_gem_request,
					    execlist_link);

	if (head_req != NULL) {
		struct drm_i915_gem_object *ctx_obj =
				head_req->ctx->engine[ring->id].state;
		if (intel_execlists_ctx_id(ctx_obj) == request_id) {
			WARN(head_req->elsp_submitted == 0,
			     "Never submitted head request\n");

			if (--head_req->elsp_submitted <= 0) {
				list_del(&head_req->execlist_link);
				list_add_tail(&head_req->execlist_link,
					&ring->execlist_retired_req_list);
				return true;
			}
		}
	}

	return false;
}

/**
 * intel_lrc_irq_handler() - handle Context Switch interrupts
 * @ring: Engine Command Streamer to handle.
 *
 * Check the unread Context Status Buffers and manage the submission of new
 * contexts to the ELSP accordingly.
 */
void intel_lrc_irq_handler(struct intel_engine_cs *ring)
{
	struct drm_i915_private *dev_priv = ring->dev->dev_private;
	u32 status_pointer;
	u8 read_pointer;
	u8 write_pointer;
	u32 status;
	u32 status_id;
	u32 submit_contexts = 0;

	status_pointer = I915_READ(RING_CONTEXT_STATUS_PTR(ring));

	read_pointer = ring->next_context_status_buffer;
	write_pointer = status_pointer & 0x07;
	if (read_pointer > write_pointer)
		write_pointer += 6;

	spin_lock(&ring->execlist_lock);

	while (read_pointer < write_pointer) {
		read_pointer++;
		status = I915_READ(RING_CONTEXT_STATUS_BUF(ring) +
				(read_pointer % 6) * 8);
		status_id = I915_READ(RING_CONTEXT_STATUS_BUF(ring) +
				(read_pointer % 6) * 8 + 4);

		if (status & GEN8_CTX_STATUS_PREEMPTED) {
			if (status & GEN8_CTX_STATUS_LITE_RESTORE) {
				if (execlists_check_remove_request(ring, status_id))
					WARN(1, "Lite Restored request removed from queue\n");
			} else
				WARN(1, "Preemption without Lite Restore\n");
		}

		 if ((status & GEN8_CTX_STATUS_ACTIVE_IDLE) ||
		     (status & GEN8_CTX_STATUS_ELEMENT_SWITCH)) {
			if (execlists_check_remove_request(ring, status_id))
				submit_contexts++;
		}
	}

	if (submit_contexts != 0)
		execlists_context_unqueue(ring);

	spin_unlock(&ring->execlist_lock);

	WARN(submit_contexts > 2, "More than two context complete events?\n");
	ring->next_context_status_buffer = write_pointer % 6;

	I915_WRITE(RING_CONTEXT_STATUS_PTR(ring),
		   ((u32)ring->next_context_status_buffer & 0x07) << 8);
}

static int execlists_context_queue(struct intel_engine_cs *ring,
				   struct intel_context *to,
				   u32 tail,
				   struct drm_i915_gem_request *request)
{
	struct drm_i915_gem_request *cursor;
	struct drm_i915_private *dev_priv = ring->dev->dev_private;
	unsigned long flags;
	int num_elements = 0;

	if (to != ring->default_context)
		intel_lr_context_pin(ring, to);

	if (!request) {
		/*
		 * If there isn't a request associated with this submission,
		 * create one as a temporary holder.
		 */
		request = kzalloc(sizeof(*request), GFP_KERNEL);
		if (request == NULL)
			return -ENOMEM;
		request->ring = ring;
		request->ctx = to;
		kref_init(&request->ref);
		request->uniq = dev_priv->request_uniq++;
		i915_gem_context_reference(request->ctx);
	} else {
		i915_gem_request_reference(request);
		WARN_ON(to != request->ctx);
	}
	request->tail = tail;

	intel_runtime_pm_get(dev_priv);

	spin_lock_irqsave(&ring->execlist_lock, flags);

	list_for_each_entry(cursor, &ring->execlist_queue, execlist_link)
		if (++num_elements > 2)
			break;

	if (num_elements > 2) {
		struct drm_i915_gem_request *tail_req;

		tail_req = list_last_entry(&ring->execlist_queue,
					   struct drm_i915_gem_request,
					   execlist_link);

		if (to == tail_req->ctx) {
			WARN(tail_req->elsp_submitted != 0,
				"More than 2 already-submitted reqs queued\n");
			list_del(&tail_req->execlist_link);
			list_add_tail(&tail_req->execlist_link,
				&ring->execlist_retired_req_list);
		}
	}

	list_add_tail(&request->execlist_link, &ring->execlist_queue);
	if (num_elements == 0)
		execlists_context_unqueue(ring);

	spin_unlock_irqrestore(&ring->execlist_lock, flags);

	return 0;
}

static int logical_ring_invalidate_all_caches(struct intel_ringbuffer *ringbuf,
					      struct intel_context *ctx)
{
	struct intel_engine_cs *ring = ringbuf->ring;
	uint32_t flush_domains;
	int ret;

	flush_domains = 0;
	if (ring->gpu_caches_dirty)
		flush_domains = I915_GEM_GPU_DOMAINS;

	ret = ring->emit_flush(ringbuf, ctx,
			       I915_GEM_GPU_DOMAINS, flush_domains);
	if (ret)
		return ret;

	ring->gpu_caches_dirty = false;
	return 0;
}

static int execlists_move_to_gpu(struct intel_ringbuffer *ringbuf,
				 struct intel_context *ctx,
				 struct list_head *vmas)
{
	struct intel_engine_cs *ring = ringbuf->ring;
	struct i915_vma *vma;
	uint32_t flush_domains = 0;
	bool flush_chipset = false;
	int ret;

	list_for_each_entry(vma, vmas, exec_list) {
		struct drm_i915_gem_object *obj = vma->obj;

		ret = i915_gem_object_sync(obj, ring);
		if (ret)
			return ret;

		if (obj->base.write_domain & I915_GEM_DOMAIN_CPU)
			flush_chipset |= i915_gem_clflush_object(obj, false);

		flush_domains |= obj->base.write_domain;
	}

	if (flush_domains & I915_GEM_DOMAIN_GTT)
		wmb();

	/* Unconditionally invalidate gpu caches and ensure that we do flush
	 * any residual writes from the previous batch.
	 */
	return logical_ring_invalidate_all_caches(ringbuf, ctx);
}

/**
 * execlists_submission() - submit a batchbuffer for execution, Execlists style
 * @dev: DRM device.
 * @file: DRM file.
 * @ring: Engine Command Streamer to submit to.
 * @ctx: Context to employ for this submission.
 * @args: execbuffer call arguments.
 * @vmas: list of vmas.
 * @batch_obj: the batchbuffer to submit.
 * @exec_start: batchbuffer start virtual address pointer.
 * @dispatch_flags: translated execbuffer call flags.
 *
 * This is the evil twin version of i915_gem_ringbuffer_submission. It abstracts
 * away the submission details of the execbuffer ioctl call.
 *
 * Return: non-zero if the submission fails.
 */
int intel_execlists_submission(struct drm_device *dev, struct drm_file *file,
			       struct intel_engine_cs *ring,
			       struct intel_context *ctx,
			       struct drm_i915_gem_execbuffer2 *args,
			       struct list_head *vmas,
			       struct drm_i915_gem_object *batch_obj,
			       u64 exec_start, u32 dispatch_flags)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;
	int instp_mode;
	u32 instp_mask;
	int ret;

	instp_mode = args->flags & I915_EXEC_CONSTANTS_MASK;
	instp_mask = I915_EXEC_CONSTANTS_MASK;
	switch (instp_mode) {
	case I915_EXEC_CONSTANTS_REL_GENERAL:
	case I915_EXEC_CONSTANTS_ABSOLUTE:
	case I915_EXEC_CONSTANTS_REL_SURFACE:
		if (instp_mode != 0 && ring != &dev_priv->ring[RCS]) {
			DRM_DEBUG("non-0 rel constants mode on non-RCS\n");
			return -EINVAL;
		}

		if (instp_mode != dev_priv->relative_constants_mode) {
			if (instp_mode == I915_EXEC_CONSTANTS_REL_SURFACE) {
				DRM_DEBUG("rel surface constants mode invalid on gen5+\n");
				return -EINVAL;
			}

			/* The HW changed the meaning on this bit on gen6 */
			instp_mask &= ~I915_EXEC_CONSTANTS_REL_SURFACE;
		}
		break;
	default:
		DRM_DEBUG("execbuf with unknown constants: %d\n", instp_mode);
		return -EINVAL;
	}

	if (args->num_cliprects != 0) {
		DRM_DEBUG("clip rectangles are only valid on pre-gen5\n");
		return -EINVAL;
	} else {
		if (args->DR4 == 0xffffffff) {
			DRM_DEBUG("UXA submitting garbage DR4, fixing up\n");
			args->DR4 = 0;
		}

		if (args->DR1 || args->DR4 || args->cliprects_ptr) {
			DRM_DEBUG("0 cliprects but dirt in cliprects fields\n");
			return -EINVAL;
		}
	}

	if (args->flags & I915_EXEC_GEN7_SOL_RESET) {
		DRM_DEBUG("sol reset is gen7 only\n");
		return -EINVAL;
	}

	ret = execlists_move_to_gpu(ringbuf, ctx, vmas);
	if (ret)
		return ret;

	if (ring == &dev_priv->ring[RCS] &&
	    instp_mode != dev_priv->relative_constants_mode) {
		ret = intel_logical_ring_begin(ringbuf, ctx, 4);
		if (ret)
			return ret;

		intel_logical_ring_emit(ringbuf, MI_NOOP);
		intel_logical_ring_emit(ringbuf, MI_LOAD_REGISTER_IMM(1));
		intel_logical_ring_emit(ringbuf, INSTPM);
		intel_logical_ring_emit(ringbuf, instp_mask << 16 | instp_mode);
		intel_logical_ring_advance(ringbuf);

		dev_priv->relative_constants_mode = instp_mode;
	}

	ret = ring->emit_bb_start(ringbuf, ctx, exec_start, dispatch_flags);
	if (ret)
		return ret;

	trace_i915_gem_ring_dispatch(intel_ring_get_request(ring), dispatch_flags);

	i915_gem_execbuffer_move_to_active(vmas, ring);
	i915_gem_execbuffer_retire_commands(dev, file, ring, batch_obj);

	return 0;
}

void intel_execlists_retire_requests(struct intel_engine_cs *ring)
{
	struct drm_i915_gem_request *req, *tmp;
	struct drm_i915_private *dev_priv = ring->dev->dev_private;
	unsigned long flags;
	struct list_head retired_list;

	WARN_ON(!mutex_is_locked(&ring->dev->struct_mutex));
	if (list_empty(&ring->execlist_retired_req_list))
		return;

	INIT_LIST_HEAD(&retired_list);
	spin_lock_irqsave(&ring->execlist_lock, flags);
	list_replace_init(&ring->execlist_retired_req_list, &retired_list);
	spin_unlock_irqrestore(&ring->execlist_lock, flags);

	list_for_each_entry_safe(req, tmp, &retired_list, execlist_link) {
		struct intel_context *ctx = req->ctx;
		struct drm_i915_gem_object *ctx_obj =
				ctx->engine[ring->id].state;

		if (ctx_obj && (ctx != ring->default_context))
			intel_lr_context_unpin(ring, ctx);
		intel_runtime_pm_put(dev_priv);
		list_del(&req->execlist_link);
		i915_gem_request_unreference(req);
	}
}

void intel_logical_ring_stop(struct intel_engine_cs *ring)
{
	struct drm_i915_private *dev_priv = ring->dev->dev_private;
	int ret;

	if (!intel_ring_initialized(ring))
		return;

	ret = intel_ring_idle(ring);
	if (ret && !i915_reset_in_progress(&to_i915(ring->dev)->gpu_error))
		DRM_ERROR("failed to quiesce %s whilst cleaning up: %d\n",
			  ring->name, ret);

	/* TODO: Is this correct with Execlists enabled? */
	I915_WRITE_MODE(ring, _MASKED_BIT_ENABLE(STOP_RING));
	if (wait_for_atomic((I915_READ_MODE(ring) & MODE_IDLE) != 0, 1000)) {
		DRM_ERROR("%s :timed out trying to stop ring\n", ring->name);
		return;
	}
	I915_WRITE_MODE(ring, _MASKED_BIT_DISABLE(STOP_RING));
}

int logical_ring_flush_all_caches(struct intel_ringbuffer *ringbuf,
				  struct intel_context *ctx)
{
	struct intel_engine_cs *ring = ringbuf->ring;
	int ret;

	if (!ring->gpu_caches_dirty)
		return 0;

	ret = ring->emit_flush(ringbuf, ctx, 0, I915_GEM_GPU_DOMAINS);
	if (ret)
		return ret;

	ring->gpu_caches_dirty = false;
	return 0;
}

/*
 * intel_logical_ring_advance_and_submit() - advance the tail and submit the workload
 * @ringbuf: Logical Ringbuffer to advance.
 *
 * The tail is updated in our logical ringbuffer struct, not in the actual context. What
 * really happens during submission is that the context and current tail will be placed
 * on a queue waiting for the ELSP to be ready to accept a new context submission. At that
 * point, the tail *inside* the context is updated and the ELSP written to.
 */
static void
intel_logical_ring_advance_and_submit(struct intel_ringbuffer *ringbuf,
				      struct intel_context *ctx,
				      struct drm_i915_gem_request *request)
{
	struct intel_engine_cs *ring = ringbuf->ring;

	intel_logical_ring_advance(ringbuf);

	if (intel_ring_stopped(ring))
		return;

	execlists_context_queue(ring, ctx, ringbuf->tail, request);
}

static int intel_lr_context_pin(struct intel_engine_cs *ring,
		struct intel_context *ctx)
{
	struct drm_i915_gem_object *ctx_obj = ctx->engine[ring->id].state;
	struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;
	int ret = 0;

	WARN_ON(!mutex_is_locked(&ring->dev->struct_mutex));
	if (ctx->engine[ring->id].pin_count++ == 0) {
		ret = i915_gem_obj_ggtt_pin(ctx_obj,
				GEN8_LR_CONTEXT_ALIGN, 0);
		if (ret)
			goto reset_pin_count;

		ret = intel_pin_and_map_ringbuffer_obj(ring->dev, ringbuf);
		if (ret)
			goto unpin_ctx_obj;
	}

	return ret;

unpin_ctx_obj:
	i915_gem_object_ggtt_unpin(ctx_obj);
reset_pin_count:
	ctx->engine[ring->id].pin_count = 0;

	return ret;
}

void intel_lr_context_unpin(struct intel_engine_cs *ring,
		struct intel_context *ctx)
{
	struct drm_i915_gem_object *ctx_obj = ctx->engine[ring->id].state;
	struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;

	if (ctx_obj) {
		WARN_ON(!mutex_is_locked(&ring->dev->struct_mutex));
		if (--ctx->engine[ring->id].pin_count == 0) {
			intel_unpin_ringbuffer_obj(ringbuf);
			i915_gem_object_ggtt_unpin(ctx_obj);
		}
	}
}

static int logical_ring_alloc_request(struct intel_engine_cs *ring,
				      struct intel_context *ctx)
{
	struct drm_i915_gem_request *request;
	struct drm_i915_private *dev_private = ring->dev->dev_private;
	int ret;

	if (ring->outstanding_lazy_request)
		return 0;

	request = kzalloc(sizeof(*request), GFP_KERNEL);
	if (request == NULL)
		return -ENOMEM;

	if (ctx != ring->default_context) {
		ret = intel_lr_context_pin(ring, ctx);
		if (ret) {
			kfree(request);
			return ret;
		}
	}

	kref_init(&request->ref);
	request->ring = ring;
	request->uniq = dev_private->request_uniq++;

	ret = i915_gem_get_seqno(ring->dev, &request->seqno);
	if (ret) {
		intel_lr_context_unpin(ring, ctx);
		kfree(request);
		return ret;
	}

	request->ctx = ctx;
	i915_gem_context_reference(request->ctx);
	request->ringbuf = ctx->engine[ring->id].ringbuf;

	ring->outstanding_lazy_request = request;
	return 0;
}

static int logical_ring_wait_request(struct intel_ringbuffer *ringbuf,
				     int bytes)
{
	struct intel_engine_cs *ring = ringbuf->ring;
	struct drm_i915_gem_request *request;
	int ret;

	if (intel_ring_space(ringbuf) >= bytes)
		return 0;

	list_for_each_entry(request, &ring->request_list, list) {
		/*
		 * The request queue is per-engine, so can contain requests
		 * from multiple ringbuffers. Here, we must ignore any that
		 * aren't from the ringbuffer we're considering.
		 */
		struct intel_context *ctx = request->ctx;
		if (ctx->engine[ring->id].ringbuf != ringbuf)
			continue;

		/* Would completion of this request free enough space? */
		if (__intel_ring_space(request->tail, ringbuf->tail,
				       ringbuf->size) >= bytes) {
			break;
		}
	}

	if (&request->list == &ring->request_list)
		return -ENOSPC;

	ret = i915_wait_request(request);
	if (ret)
		return ret;

	i915_gem_retire_requests_ring(ring);

	return intel_ring_space(ringbuf) >= bytes ? 0 : -ENOSPC;
}

static int logical_ring_wait_for_space(struct intel_ringbuffer *ringbuf,
				       struct intel_context *ctx,
				       int bytes)
{
	struct intel_engine_cs *ring = ringbuf->ring;
	struct drm_device *dev = ring->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	unsigned long end;
	int ret;

	ret = logical_ring_wait_request(ringbuf, bytes);
	if (ret != -ENOSPC)
		return ret;

	/* Force the context submission in case we have been skipping it */
	intel_logical_ring_advance_and_submit(ringbuf, ctx, NULL);

	/* With GEM the hangcheck timer should kick us out of the loop,
	 * leaving it early runs the risk of corrupting GEM state (due
	 * to running on almost untested codepaths). But on resume
	 * timers don't work yet, so prevent a complete hang in that
	 * case by choosing an insanely large timeout. */
	end = jiffies + 60 * HZ;

	ret = 0;
	do {
		if (intel_ring_space(ringbuf) >= bytes)
			break;

		msleep(1);

		if (dev_priv->mm.interruptible && signal_pending(current)) {
			ret = -ERESTARTSYS;
			break;
		}

		ret = i915_gem_check_wedge(&dev_priv->gpu_error,
					   dev_priv->mm.interruptible);
		if (ret)
			break;

		if (time_after(jiffies, end)) {
			ret = -EBUSY;
			break;
		}
	} while (1);

	return ret;
}

static int logical_ring_wrap_buffer(struct intel_ringbuffer *ringbuf,
				    struct intel_context *ctx)
{
	uint32_t __iomem *virt;
	int rem = ringbuf->size - ringbuf->tail;

	if (ringbuf->space < rem) {
		int ret = logical_ring_wait_for_space(ringbuf, ctx, rem);

		if (ret)
			return ret;
	}

	virt = ringbuf->virtual_start + ringbuf->tail;
	rem /= 4;
	while (rem--)
		iowrite32(MI_NOOP, virt++);

	ringbuf->tail = 0;
	intel_ring_update_space(ringbuf);

	return 0;
}

static int logical_ring_prepare(struct intel_ringbuffer *ringbuf,
				struct intel_context *ctx, int bytes)
{
	int ret;

	if (unlikely(ringbuf->tail + bytes > ringbuf->effective_size)) {
		ret = logical_ring_wrap_buffer(ringbuf, ctx);
		if (unlikely(ret))
			return ret;
	}

	if (unlikely(ringbuf->space < bytes)) {
		ret = logical_ring_wait_for_space(ringbuf, ctx, bytes);
		if (unlikely(ret))
			return ret;
	}

	return 0;
}

/**
 * intel_logical_ring_begin() - prepare the logical ringbuffer to accept some commands
 *
 * @ringbuf: Logical ringbuffer.
 * @num_dwords: number of DWORDs that we plan to write to the ringbuffer.
 *
 * The ringbuffer might not be ready to accept the commands right away (maybe it needs to
 * be wrapped, or wait a bit for the tail to be updated). This function takes care of that
 * and also preallocates a request (every workload submission is still mediated through
 * requests, same as it did with legacy ringbuffer submission).
 *
 * Return: non-zero if the ringbuffer is not ready to be written to.
 */
int intel_logical_ring_begin(struct intel_ringbuffer *ringbuf,
			     struct intel_context *ctx, int num_dwords)
{
	struct intel_engine_cs *ring = ringbuf->ring;
	struct drm_device *dev = ring->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	int ret;

	ret = i915_gem_check_wedge(&dev_priv->gpu_error,
				   dev_priv->mm.interruptible);
	if (ret)
		return ret;

	ret = logical_ring_prepare(ringbuf, ctx, num_dwords * sizeof(uint32_t));
	if (ret)
		return ret;

	/* Preallocate the olr before touching the ring */
	ret = logical_ring_alloc_request(ring, ctx);
	if (ret)
		return ret;

	ringbuf->space -= num_dwords * sizeof(uint32_t);
	return 0;
}

static int intel_logical_ring_workarounds_emit(struct intel_engine_cs *ring,
					       struct intel_context *ctx)
{
	int ret, i;
	struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;
	struct drm_device *dev = ring->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct i915_workarounds *w = &dev_priv->workarounds;

	if (WARN_ON_ONCE(w->count == 0))
		return 0;

	ring->gpu_caches_dirty = true;
	ret = logical_ring_flush_all_caches(ringbuf, ctx);
	if (ret)
		return ret;

	ret = intel_logical_ring_begin(ringbuf, ctx, w->count * 2 + 2);
	if (ret)
		return ret;

	intel_logical_ring_emit(ringbuf, MI_LOAD_REGISTER_IMM(w->count));
	for (i = 0; i < w->count; i++) {
		intel_logical_ring_emit(ringbuf, w->reg[i].addr);
		intel_logical_ring_emit(ringbuf, w->reg[i].value);
	}
	intel_logical_ring_emit(ringbuf, MI_NOOP);

	intel_logical_ring_advance(ringbuf);

	ring->gpu_caches_dirty = true;
	ret = logical_ring_flush_all_caches(ringbuf, ctx);
	if (ret)
		return ret;

	return 0;
}

static int gen8_init_common_ring(struct intel_engine_cs *ring)
{
	struct drm_device *dev = ring->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;

	I915_WRITE_IMR(ring, ~(ring->irq_enable_mask | ring->irq_keep_mask));
	I915_WRITE(RING_HWSTAM(ring->mmio_base), 0xffffffff);

	if (ring->status_page.obj) {
		I915_WRITE(RING_HWS_PGA(ring->mmio_base),
			   (u32)ring->status_page.gfx_addr);
		POSTING_READ(RING_HWS_PGA(ring->mmio_base));
	}

	I915_WRITE(RING_MODE_GEN7(ring),
		   _MASKED_BIT_DISABLE(GFX_REPLAY_MODE) |
		   _MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE));
	POSTING_READ(RING_MODE_GEN7(ring));
	ring->next_context_status_buffer = 0;
	DRM_DEBUG_DRIVER("Execlists enabled for %s\n", ring->name);

	memset(&ring->hangcheck, 0, sizeof(ring->hangcheck));

	return 0;
}

static int gen8_init_render_ring(struct intel_engine_cs *ring)
{
	struct drm_device *dev = ring->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	int ret;

	ret = gen8_init_common_ring(ring);
	if (ret)
		return ret;

	/* We need to disable the AsyncFlip performance optimisations in order
	 * to use MI_WAIT_FOR_EVENT within the CS. It should already be
	 * programmed to '1' on all products.
	 *
	 * WaDisableAsyncFlipPerfMode:snb,ivb,hsw,vlv,bdw,chv
	 */
	I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(ASYNC_FLIP_PERF_DISABLE));

	I915_WRITE(INSTPM, _MASKED_BIT_ENABLE(INSTPM_FORCE_ORDERING));

	return init_workarounds_ring(ring);
}

static int gen9_init_render_ring(struct intel_engine_cs *ring)
{
	int ret;

	ret = gen8_init_common_ring(ring);
	if (ret)
		return ret;

	return init_workarounds_ring(ring);
}

static int gen8_emit_bb_start(struct intel_ringbuffer *ringbuf,
			      struct intel_context *ctx,
			      u64 offset, unsigned dispatch_flags)
{
	bool ppgtt = !(dispatch_flags & I915_DISPATCH_SECURE);
	int ret;

	ret = intel_logical_ring_begin(ringbuf, ctx, 4);
	if (ret)
		return ret;

	/* FIXME(BDW): Address space and security selectors. */
	intel_logical_ring_emit(ringbuf, MI_BATCH_BUFFER_START_GEN8 | (ppgtt<<8));
	intel_logical_ring_emit(ringbuf, lower_32_bits(offset));
	intel_logical_ring_emit(ringbuf, upper_32_bits(offset));
	intel_logical_ring_emit(ringbuf, MI_NOOP);
	intel_logical_ring_advance(ringbuf);

	return 0;
}

static bool gen8_logical_ring_get_irq(struct intel_engine_cs *ring)
{
	struct drm_device *dev = ring->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	unsigned long flags;

	if (WARN_ON(!intel_irqs_enabled(dev_priv)))
		return false;

	spin_lock_irqsave(&dev_priv->irq_lock, flags);
	if (ring->irq_refcount++ == 0) {
		I915_WRITE_IMR(ring, ~(ring->irq_enable_mask | ring->irq_keep_mask));
		POSTING_READ(RING_IMR(ring->mmio_base));
	}
	spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

	return true;
}

static void gen8_logical_ring_put_irq(struct intel_engine_cs *ring)
{
	struct drm_device *dev = ring->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	unsigned long flags;

	spin_lock_irqsave(&dev_priv->irq_lock, flags);
	if (--ring->irq_refcount == 0) {
		I915_WRITE_IMR(ring, ~ring->irq_keep_mask);
		POSTING_READ(RING_IMR(ring->mmio_base));
	}
	spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
}

static int gen8_emit_flush(struct intel_ringbuffer *ringbuf,
			   struct intel_context *ctx,
			   u32 invalidate_domains,
			   u32 unused)
{
	struct intel_engine_cs *ring = ringbuf->ring;
	struct drm_device *dev = ring->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	uint32_t cmd;
	int ret;

	ret = intel_logical_ring_begin(ringbuf, ctx, 4);
	if (ret)
		return ret;

	cmd = MI_FLUSH_DW + 1;

	/* We always require a command barrier so that subsequent
	 * commands, such as breadcrumb interrupts, are strictly ordered
	 * wrt the contents of the write cache being flushed to memory
	 * (and thus being coherent from the CPU).
	 */
	cmd |= MI_FLUSH_DW_STORE_INDEX | MI_FLUSH_DW_OP_STOREDW;

	if (invalidate_domains & I915_GEM_GPU_DOMAINS) {
		cmd |= MI_INVALIDATE_TLB;
		if (ring == &dev_priv->ring[VCS])
			cmd |= MI_INVALIDATE_BSD;
	}

	intel_logical_ring_emit(ringbuf, cmd);
	intel_logical_ring_emit(ringbuf,
				I915_GEM_HWS_SCRATCH_ADDR |
				MI_FLUSH_DW_USE_GTT);
	intel_logical_ring_emit(ringbuf, 0); /* upper addr */
	intel_logical_ring_emit(ringbuf, 0); /* value */
	intel_logical_ring_advance(ringbuf);

	return 0;
}

static int gen8_emit_flush_render(struct intel_ringbuffer *ringbuf,
				  struct intel_context *ctx,
				  u32 invalidate_domains,
				  u32 flush_domains)
{
	struct intel_engine_cs *ring = ringbuf->ring;
	u32 scratch_addr = ring->scratch.gtt_offset + 2 * CACHELINE_BYTES;
	u32 flags = 0;
	int ret;

	flags |= PIPE_CONTROL_CS_STALL;

	if (flush_domains) {
		flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
		flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
	}

	if (invalidate_domains) {
		flags |= PIPE_CONTROL_TLB_INVALIDATE;
		flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
		flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
		flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
		flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
		flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
		flags |= PIPE_CONTROL_QW_WRITE;
		flags |= PIPE_CONTROL_GLOBAL_GTT_IVB;
	}

	ret = intel_logical_ring_begin(ringbuf, ctx, 6);
	if (ret)
		return ret;

	intel_logical_ring_emit(ringbuf, GFX_OP_PIPE_CONTROL(6));
	intel_logical_ring_emit(ringbuf, flags);
	intel_logical_ring_emit(ringbuf, scratch_addr);
	intel_logical_ring_emit(ringbuf, 0);
	intel_logical_ring_emit(ringbuf, 0);
	intel_logical_ring_emit(ringbuf, 0);
	intel_logical_ring_advance(ringbuf);

	return 0;
}

static u32 gen8_get_seqno(struct intel_engine_cs *ring, bool lazy_coherency)
{
	return intel_read_status_page(ring, I915_GEM_HWS_INDEX);
}

static void gen8_set_seqno(struct intel_engine_cs *ring, u32 seqno)
{
	intel_write_status_page(ring, I915_GEM_HWS_INDEX, seqno);
}

static int gen8_emit_request(struct intel_ringbuffer *ringbuf,
			     struct drm_i915_gem_request *request)
{
	struct intel_engine_cs *ring = ringbuf->ring;
	u32 cmd;
	int ret;

	/*
	 * Reserve space for 2 NOOPs at the end of each request to be
	 * used as a workaround for not being allowed to do lite
	 * restore with HEAD==TAIL (WaIdleLiteRestore).
	 */
	ret = intel_logical_ring_begin(ringbuf, request->ctx, 8);
	if (ret)
		return ret;

	cmd = MI_STORE_DWORD_IMM_GEN4;
	cmd |= MI_GLOBAL_GTT;

	intel_logical_ring_emit(ringbuf, cmd);
	intel_logical_ring_emit(ringbuf,
				(ring->status_page.gfx_addr +
				(I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT)));
	intel_logical_ring_emit(ringbuf, 0);
	intel_logical_ring_emit(ringbuf,
		i915_gem_request_get_seqno(ring->outstanding_lazy_request));
	intel_logical_ring_emit(ringbuf, MI_USER_INTERRUPT);
	intel_logical_ring_emit(ringbuf, MI_NOOP);
	intel_logical_ring_advance_and_submit(ringbuf, request->ctx, request);

	/*
	 * Here we add two extra NOOPs as padding to avoid
	 * lite restore of a context with HEAD==TAIL.
	 */
	intel_logical_ring_emit(ringbuf, MI_NOOP);
	intel_logical_ring_emit(ringbuf, MI_NOOP);
	intel_logical_ring_advance(ringbuf);

	return 0;
}

static int intel_lr_context_render_state_init(struct intel_engine_cs *ring,
					      struct intel_context *ctx)
{
	struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;
	struct render_state so;
	struct drm_i915_file_private *file_priv = ctx->file_priv;
	struct drm_file *file = file_priv ? file_priv->file : NULL;
	int ret;

	ret = i915_gem_render_state_prepare(ring, &so);
	if (ret)
		return ret;

	if (so.rodata == NULL)
		return 0;

	ret = ring->emit_bb_start(ringbuf,
			ctx,
			so.ggtt_offset,
			I915_DISPATCH_SECURE);
	if (ret)
		goto out;

	i915_vma_move_to_active(i915_gem_obj_to_ggtt(so.obj), ring);

	ret = __i915_add_request(ring, file, so.obj);
	/* intel_logical_ring_add_request moves object to inactive if it
	 * fails */
out:
	i915_gem_render_state_fini(&so);
	return ret;
}

static int gen8_init_rcs_context(struct intel_engine_cs *ring,
		       struct intel_context *ctx)
{
	int ret;

	ret = intel_logical_ring_workarounds_emit(ring, ctx);
	if (ret)
		return ret;

	return intel_lr_context_render_state_init(ring, ctx);
}

/**
 * intel_logical_ring_cleanup() - deallocate the Engine Command Streamer
 *
 * @ring: Engine Command Streamer.
 *
 */
void intel_logical_ring_cleanup(struct intel_engine_cs *ring)
{
	struct drm_i915_private *dev_priv;

	if (!intel_ring_initialized(ring))
		return;

	dev_priv = ring->dev->dev_private;

	intel_logical_ring_stop(ring);
	WARN_ON((I915_READ_MODE(ring) & MODE_IDLE) == 0);
	i915_gem_request_assign(&ring->outstanding_lazy_request, NULL);

	if (ring->cleanup)
		ring->cleanup(ring);

	i915_cmd_parser_fini_ring(ring);

	if (ring->status_page.obj) {
		kunmap(sg_page(ring->status_page.obj->pages->sgl));
		ring->status_page.obj = NULL;
	}
}

static int logical_ring_init(struct drm_device *dev, struct intel_engine_cs *ring)
{
	int ret;

	/* Intentionally left blank. */
	ring->buffer = NULL;

	ring->dev = dev;
	INIT_LIST_HEAD(&ring->active_list);
	INIT_LIST_HEAD(&ring->request_list);
	init_waitqueue_head(&ring->irq_queue);

	INIT_LIST_HEAD(&ring->execlist_queue);
	INIT_LIST_HEAD(&ring->execlist_retired_req_list);
	spin_lock_init(&ring->execlist_lock);

	ret = i915_cmd_parser_init_ring(ring);
	if (ret)
		return ret;

	ret = intel_lr_context_deferred_create(ring->default_context, ring);

	return ret;
}

static int logical_render_ring_init(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_engine_cs *ring = &dev_priv->ring[RCS];
	int ret;

	ring->name = "render ring";
	ring->id = RCS;
	ring->mmio_base = RENDER_RING_BASE;
	ring->irq_enable_mask =
		GT_RENDER_USER_INTERRUPT << GEN8_RCS_IRQ_SHIFT;
	ring->irq_keep_mask =
		GT_CONTEXT_SWITCH_INTERRUPT << GEN8_RCS_IRQ_SHIFT;
	if (HAS_L3_DPF(dev))
		ring->irq_keep_mask |= GT_RENDER_L3_PARITY_ERROR_INTERRUPT;

	if (INTEL_INFO(dev)->gen >= 9)
		ring->init_hw = gen9_init_render_ring;
	else
		ring->init_hw = gen8_init_render_ring;
	ring->init_context = gen8_init_rcs_context;
	ring->cleanup = intel_fini_pipe_control;
	ring->get_seqno = gen8_get_seqno;
	ring->set_seqno = gen8_set_seqno;
	ring->emit_request = gen8_emit_request;
	ring->emit_flush = gen8_emit_flush_render;
	ring->irq_get = gen8_logical_ring_get_irq;
	ring->irq_put = gen8_logical_ring_put_irq;
	ring->emit_bb_start = gen8_emit_bb_start;

	ring->dev = dev;
	ret = logical_ring_init(dev, ring);
	if (ret)
		return ret;

	return intel_init_pipe_control(ring);
}

static int logical_bsd_ring_init(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_engine_cs *ring = &dev_priv->ring[VCS];

	ring->name = "bsd ring";
	ring->id = VCS;
	ring->mmio_base = GEN6_BSD_RING_BASE;
	ring->irq_enable_mask =
		GT_RENDER_USER_INTERRUPT << GEN8_VCS1_IRQ_SHIFT;
	ring->irq_keep_mask =
		GT_CONTEXT_SWITCH_INTERRUPT << GEN8_VCS1_IRQ_SHIFT;

	ring->init_hw = gen8_init_common_ring;
	ring->get_seqno = gen8_get_seqno;
	ring->set_seqno = gen8_set_seqno;
	ring->emit_request = gen8_emit_request;
	ring->emit_flush = gen8_emit_flush;
	ring->irq_get = gen8_logical_ring_get_irq;
	ring->irq_put = gen8_logical_ring_put_irq;
	ring->emit_bb_start = gen8_emit_bb_start;

	return logical_ring_init(dev, ring);
}

static int logical_bsd2_ring_init(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_engine_cs *ring = &dev_priv->ring[VCS2];

	ring->name = "bds2 ring";
	ring->id = VCS2;
	ring->mmio_base = GEN8_BSD2_RING_BASE;
	ring->irq_enable_mask =
		GT_RENDER_USER_INTERRUPT << GEN8_VCS2_IRQ_SHIFT;
	ring->irq_keep_mask =
		GT_CONTEXT_SWITCH_INTERRUPT << GEN8_VCS2_IRQ_SHIFT;

	ring->init_hw = gen8_init_common_ring;
	ring->get_seqno = gen8_get_seqno;
	ring->set_seqno = gen8_set_seqno;
	ring->emit_request = gen8_emit_request;
	ring->emit_flush = gen8_emit_flush;
	ring->irq_get = gen8_logical_ring_get_irq;
	ring->irq_put = gen8_logical_ring_put_irq;
	ring->emit_bb_start = gen8_emit_bb_start;

	return logical_ring_init(dev, ring);
}

static int logical_blt_ring_init(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_engine_cs *ring = &dev_priv->ring[BCS];

	ring->name = "blitter ring";
	ring->id = BCS;
	ring->mmio_base = BLT_RING_BASE;
	ring->irq_enable_mask =
		GT_RENDER_USER_INTERRUPT << GEN8_BCS_IRQ_SHIFT;
	ring->irq_keep_mask =
		GT_CONTEXT_SWITCH_INTERRUPT << GEN8_BCS_IRQ_SHIFT;

	ring->init_hw = gen8_init_common_ring;
	ring->get_seqno = gen8_get_seqno;
	ring->set_seqno = gen8_set_seqno;
	ring->emit_request = gen8_emit_request;
	ring->emit_flush = gen8_emit_flush;
	ring->irq_get = gen8_logical_ring_get_irq;
	ring->irq_put = gen8_logical_ring_put_irq;
	ring->emit_bb_start = gen8_emit_bb_start;

	return logical_ring_init(dev, ring);
}

static int logical_vebox_ring_init(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_engine_cs *ring = &dev_priv->ring[VECS];

	ring->name = "video enhancement ring";
	ring->id = VECS;
	ring->mmio_base = VEBOX_RING_BASE;
	ring->irq_enable_mask =
		GT_RENDER_USER_INTERRUPT << GEN8_VECS_IRQ_SHIFT;
	ring->irq_keep_mask =
		GT_CONTEXT_SWITCH_INTERRUPT << GEN8_VECS_IRQ_SHIFT;

	ring->init_hw = gen8_init_common_ring;
	ring->get_seqno = gen8_get_seqno;
	ring->set_seqno = gen8_set_seqno;
	ring->emit_request = gen8_emit_request;
	ring->emit_flush = gen8_emit_flush;
	ring->irq_get = gen8_logical_ring_get_irq;
	ring->irq_put = gen8_logical_ring_put_irq;
	ring->emit_bb_start = gen8_emit_bb_start;

	return logical_ring_init(dev, ring);
}

/**
 * intel_logical_rings_init() - allocate, populate and init the Engine Command Streamers
 * @dev: DRM device.
 *
 * This function inits the engines for an Execlists submission style (the equivalent in the
 * legacy ringbuffer submission world would be i915_gem_init_rings). It does it only for
 * those engines that are present in the hardware.
 *
 * Return: non-zero if the initialization failed.
 */
int intel_logical_rings_init(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	int ret;

	ret = logical_render_ring_init(dev);
	if (ret)
		return ret;

	if (HAS_BSD(dev)) {
		ret = logical_bsd_ring_init(dev);
		if (ret)
			goto cleanup_render_ring;
	}

	if (HAS_BLT(dev)) {
		ret = logical_blt_ring_init(dev);
		if (ret)
			goto cleanup_bsd_ring;
	}

	if (HAS_VEBOX(dev)) {
		ret = logical_vebox_ring_init(dev);
		if (ret)
			goto cleanup_blt_ring;
	}

	if (HAS_BSD2(dev)) {
		ret = logical_bsd2_ring_init(dev);
		if (ret)
			goto cleanup_vebox_ring;
	}

	ret = i915_gem_set_seqno(dev, ((u32)~0 - 0x1000));
	if (ret)
		goto cleanup_bsd2_ring;

	return 0;

cleanup_bsd2_ring:
	intel_logical_ring_cleanup(&dev_priv->ring[VCS2]);
cleanup_vebox_ring:
	intel_logical_ring_cleanup(&dev_priv->ring[VECS]);
cleanup_blt_ring:
	intel_logical_ring_cleanup(&dev_priv->ring[BCS]);
cleanup_bsd_ring:
	intel_logical_ring_cleanup(&dev_priv->ring[VCS]);
cleanup_render_ring:
	intel_logical_ring_cleanup(&dev_priv->ring[RCS]);

	return ret;
}

static u32
make_rpcs(struct drm_device *dev)
{
	u32 rpcs = 0;

	/*
	 * No explicit RPCS request is needed to ensure full
	 * slice/subslice/EU enablement prior to Gen9.
	*/
	if (INTEL_INFO(dev)->gen < 9)
		return 0;

	/*
	 * Starting in Gen9, render power gating can leave
	 * slice/subslice/EU in a partially enabled state. We
	 * must make an explicit request through RPCS for full
	 * enablement.
	*/
	if (INTEL_INFO(dev)->has_slice_pg) {
		rpcs |= GEN8_RPCS_S_CNT_ENABLE;
		rpcs |= INTEL_INFO(dev)->slice_total <<
			GEN8_RPCS_S_CNT_SHIFT;
		rpcs |= GEN8_RPCS_ENABLE;
	}

	if (INTEL_INFO(dev)->has_subslice_pg) {
		rpcs |= GEN8_RPCS_SS_CNT_ENABLE;
		rpcs |= INTEL_INFO(dev)->subslice_per_slice <<
			GEN8_RPCS_SS_CNT_SHIFT;
		rpcs |= GEN8_RPCS_ENABLE;
	}

	if (INTEL_INFO(dev)->has_eu_pg) {
		rpcs |= INTEL_INFO(dev)->eu_per_subslice <<
			GEN8_RPCS_EU_MIN_SHIFT;
		rpcs |= INTEL_INFO(dev)->eu_per_subslice <<
			GEN8_RPCS_EU_MAX_SHIFT;
		rpcs |= GEN8_RPCS_ENABLE;
	}

	return rpcs;
}

static int
populate_lr_context(struct intel_context *ctx, struct drm_i915_gem_object *ctx_obj,
		    struct intel_engine_cs *ring, struct intel_ringbuffer *ringbuf)
{
	struct drm_device *dev = ring->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct i915_hw_ppgtt *ppgtt = ctx->ppgtt;
	struct page *page;
	uint32_t *reg_state;
	int ret;

	if (!ppgtt)
		ppgtt = dev_priv->mm.aliasing_ppgtt;

	ret = i915_gem_object_set_to_cpu_domain(ctx_obj, true);
	if (ret) {
		DRM_DEBUG_DRIVER("Could not set to CPU domain\n");
		return ret;
	}

	ret = i915_gem_object_get_pages(ctx_obj);
	if (ret) {
		DRM_DEBUG_DRIVER("Could not get object pages\n");
		return ret;
	}

	i915_gem_object_pin_pages(ctx_obj);

	/* The second page of the context object contains some fields which must
	 * be set up prior to the first execution. */
	page = i915_gem_object_get_page(ctx_obj, 1);
	reg_state = kmap_atomic(page);

	/* A context is actually a big batch buffer with several MI_LOAD_REGISTER_IMM
	 * commands followed by (reg, value) pairs. The values we are setting here are
	 * only for the first context restore: on a subsequent save, the GPU will
	 * recreate this batchbuffer with new values (including all the missing
	 * MI_LOAD_REGISTER_IMM commands that we are not initializing here). */
	if (ring->id == RCS)
		reg_state[CTX_LRI_HEADER_0] = MI_LOAD_REGISTER_IMM(14);
	else
		reg_state[CTX_LRI_HEADER_0] = MI_LOAD_REGISTER_IMM(11);
	reg_state[CTX_LRI_HEADER_0] |= MI_LRI_FORCE_POSTED;
	reg_state[CTX_CONTEXT_CONTROL] = RING_CONTEXT_CONTROL(ring);
	reg_state[CTX_CONTEXT_CONTROL+1] =
		_MASKED_BIT_ENABLE(CTX_CTRL_INHIBIT_SYN_CTX_SWITCH |
				CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT);
	reg_state[CTX_RING_HEAD] = RING_HEAD(ring->mmio_base);
	reg_state[CTX_RING_HEAD+1] = 0;
	reg_state[CTX_RING_TAIL] = RING_TAIL(ring->mmio_base);
	reg_state[CTX_RING_TAIL+1] = 0;
	reg_state[CTX_RING_BUFFER_START] = RING_START(ring->mmio_base);
	/* Ring buffer start address is not known until the buffer is pinned.
	 * It is written to the context image in execlists_update_context()
	 */
	reg_state[CTX_RING_BUFFER_CONTROL] = RING_CTL(ring->mmio_base);
	reg_state[CTX_RING_BUFFER_CONTROL+1] =
			((ringbuf->size - PAGE_SIZE) & RING_NR_PAGES) | RING_VALID;
	reg_state[CTX_BB_HEAD_U] = ring->mmio_base + 0x168;
	reg_state[CTX_BB_HEAD_U+1] = 0;
	reg_state[CTX_BB_HEAD_L] = ring->mmio_base + 0x140;
	reg_state[CTX_BB_HEAD_L+1] = 0;
	reg_state[CTX_BB_STATE] = ring->mmio_base + 0x110;
	reg_state[CTX_BB_STATE+1] = (1<<5);
	reg_state[CTX_SECOND_BB_HEAD_U] = ring->mmio_base + 0x11c;
	reg_state[CTX_SECOND_BB_HEAD_U+1] = 0;
	reg_state[CTX_SECOND_BB_HEAD_L] = ring->mmio_base + 0x114;
	reg_state[CTX_SECOND_BB_HEAD_L+1] = 0;
	reg_state[CTX_SECOND_BB_STATE] = ring->mmio_base + 0x118;
	reg_state[CTX_SECOND_BB_STATE+1] = 0;
	if (ring->id == RCS) {
		/* TODO: according to BSpec, the register state context
		 * for CHV does not have these. OTOH, these registers do
		 * exist in CHV. I'm waiting for a clarification */
		reg_state[CTX_BB_PER_CTX_PTR] = ring->mmio_base + 0x1c0;
		reg_state[CTX_BB_PER_CTX_PTR+1] = 0;
		reg_state[CTX_RCS_INDIRECT_CTX] = ring->mmio_base + 0x1c4;
		reg_state[CTX_RCS_INDIRECT_CTX+1] = 0;
		reg_state[CTX_RCS_INDIRECT_CTX_OFFSET] = ring->mmio_base + 0x1c8;
		reg_state[CTX_RCS_INDIRECT_CTX_OFFSET+1] = 0;
	}
	reg_state[CTX_LRI_HEADER_1] = MI_LOAD_REGISTER_IMM(9);
	reg_state[CTX_LRI_HEADER_1] |= MI_LRI_FORCE_POSTED;
	reg_state[CTX_CTX_TIMESTAMP] = ring->mmio_base + 0x3a8;
	reg_state[CTX_CTX_TIMESTAMP+1] = 0;
	reg_state[CTX_PDP3_UDW] = GEN8_RING_PDP_UDW(ring, 3);
	reg_state[CTX_PDP3_LDW] = GEN8_RING_PDP_LDW(ring, 3);
	reg_state[CTX_PDP2_UDW] = GEN8_RING_PDP_UDW(ring, 2);
	reg_state[CTX_PDP2_LDW] = GEN8_RING_PDP_LDW(ring, 2);
	reg_state[CTX_PDP1_UDW] = GEN8_RING_PDP_UDW(ring, 1);
	reg_state[CTX_PDP1_LDW] = GEN8_RING_PDP_LDW(ring, 1);
	reg_state[CTX_PDP0_UDW] = GEN8_RING_PDP_UDW(ring, 0);
	reg_state[CTX_PDP0_LDW] = GEN8_RING_PDP_LDW(ring, 0);
	reg_state[CTX_PDP3_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[3]->daddr);
	reg_state[CTX_PDP3_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[3]->daddr);
	reg_state[CTX_PDP2_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[2]->daddr);
	reg_state[CTX_PDP2_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[2]->daddr);
	reg_state[CTX_PDP1_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[1]->daddr);
	reg_state[CTX_PDP1_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[1]->daddr);
	reg_state[CTX_PDP0_UDW+1] = upper_32_bits(ppgtt->pdp.page_directory[0]->daddr);
	reg_state[CTX_PDP0_LDW+1] = lower_32_bits(ppgtt->pdp.page_directory[0]->daddr);
	if (ring->id == RCS) {
		reg_state[CTX_LRI_HEADER_2] = MI_LOAD_REGISTER_IMM(1);
		reg_state[CTX_R_PWR_CLK_STATE] = GEN8_R_PWR_CLK_STATE;
		reg_state[CTX_R_PWR_CLK_STATE+1] = make_rpcs(dev);
	}

	kunmap_atomic(reg_state);

	ctx_obj->dirty = 1;
	set_page_dirty(page);
	i915_gem_object_unpin_pages(ctx_obj);

	return 0;
}

/**
 * intel_lr_context_free() - free the LRC specific bits of a context
 * @ctx: the LR context to free.
 *
 * The real context freeing is done in i915_gem_context_free: this only
 * takes care of the bits that are LRC related: the per-engine backing
 * objects and the logical ringbuffer.
 */
void intel_lr_context_free(struct intel_context *ctx)
{
	int i;

	for (i = 0; i < I915_NUM_RINGS; i++) {
		struct drm_i915_gem_object *ctx_obj = ctx->engine[i].state;

		if (ctx_obj) {
			struct intel_ringbuffer *ringbuf =
					ctx->engine[i].ringbuf;
			struct intel_engine_cs *ring = ringbuf->ring;

			if (ctx == ring->default_context) {
				intel_unpin_ringbuffer_obj(ringbuf);
				i915_gem_object_ggtt_unpin(ctx_obj);
			}
			WARN_ON(ctx->engine[ring->id].pin_count);
			intel_destroy_ringbuffer_obj(ringbuf);
			kfree(ringbuf);
			drm_gem_object_unreference(&ctx_obj->base);
		}
	}
}

static uint32_t get_lr_context_size(struct intel_engine_cs *ring)
{
	int ret = 0;

	WARN_ON(INTEL_INFO(ring->dev)->gen < 8);

	switch (ring->id) {
	case RCS:
		if (INTEL_INFO(ring->dev)->gen >= 9)
			ret = GEN9_LR_CONTEXT_RENDER_SIZE;
		else
			ret = GEN8_LR_CONTEXT_RENDER_SIZE;
		break;
	case VCS:
	case BCS:
	case VECS:
	case VCS2:
		ret = GEN8_LR_CONTEXT_OTHER_SIZE;
		break;
	}

	return ret;
}

static void lrc_setup_hardware_status_page(struct intel_engine_cs *ring,
		struct drm_i915_gem_object *default_ctx_obj)
{
	struct drm_i915_private *dev_priv = ring->dev->dev_private;

	/* The status page is offset 0 from the default context object
	 * in LRC mode. */
	ring->status_page.gfx_addr = i915_gem_obj_ggtt_offset(default_ctx_obj);
	ring->status_page.page_addr =
			kmap(sg_page(default_ctx_obj->pages->sgl));
	ring->status_page.obj = default_ctx_obj;

	I915_WRITE(RING_HWS_PGA(ring->mmio_base),
			(u32)ring->status_page.gfx_addr);
	POSTING_READ(RING_HWS_PGA(ring->mmio_base));
}

/**
 * intel_lr_context_deferred_create() - create the LRC specific bits of a context
 * @ctx: LR context to create.
 * @ring: engine to be used with the context.
 *
 * This function can be called more than once, with different engines, if we plan
 * to use the context with them. The context backing objects and the ringbuffers
 * (specially the ringbuffer backing objects) suck a lot of memory up, and that's why
 * the creation is a deferred call: it's better to make sure first that we need to use
 * a given ring with the context.
 *
 * Return: non-zero on error.
 */
int intel_lr_context_deferred_create(struct intel_context *ctx,
				     struct intel_engine_cs *ring)
{
	const bool is_global_default_ctx = (ctx == ring->default_context);
	struct drm_device *dev = ring->dev;
	struct drm_i915_gem_object *ctx_obj;
	uint32_t context_size;
	struct intel_ringbuffer *ringbuf;
	int ret;

	WARN_ON(ctx->legacy_hw_ctx.rcs_state != NULL);
	WARN_ON(ctx->engine[ring->id].state);

	context_size = round_up(get_lr_context_size(ring), 4096);

	ctx_obj = i915_gem_alloc_context_obj(dev, context_size);
	if (IS_ERR(ctx_obj)) {
		ret = PTR_ERR(ctx_obj);
		DRM_DEBUG_DRIVER("Alloc LRC backing obj failed: %d\n", ret);
		return ret;
	}

	if (is_global_default_ctx) {
		ret = i915_gem_obj_ggtt_pin(ctx_obj, GEN8_LR_CONTEXT_ALIGN, 0);
		if (ret) {
			DRM_DEBUG_DRIVER("Pin LRC backing obj failed: %d\n",
					ret);
			drm_gem_object_unreference(&ctx_obj->base);
			return ret;
		}
	}

	ringbuf = kzalloc(sizeof(*ringbuf), GFP_KERNEL);
	if (!ringbuf) {
		DRM_DEBUG_DRIVER("Failed to allocate ringbuffer %s\n",
				ring->name);
		ret = -ENOMEM;
		goto error_unpin_ctx;
	}

	ringbuf->ring = ring;

	ringbuf->size = 32 * PAGE_SIZE;
	ringbuf->effective_size = ringbuf->size;
	ringbuf->head = 0;
	ringbuf->tail = 0;
	ringbuf->last_retired_head = -1;
	intel_ring_update_space(ringbuf);

	if (ringbuf->obj == NULL) {
		ret = intel_alloc_ringbuffer_obj(dev, ringbuf);
		if (ret) {
			DRM_DEBUG_DRIVER(
				"Failed to allocate ringbuffer obj %s: %d\n",
				ring->name, ret);
			goto error_free_rbuf;
		}

		if (is_global_default_ctx) {
			ret = intel_pin_and_map_ringbuffer_obj(dev, ringbuf);
			if (ret) {
				DRM_ERROR(
					"Failed to pin and map ringbuffer %s: %d\n",
					ring->name, ret);
				goto error_destroy_rbuf;
			}
		}

	}

	ret = populate_lr_context(ctx, ctx_obj, ring, ringbuf);
	if (ret) {
		DRM_DEBUG_DRIVER("Failed to populate LRC: %d\n", ret);
		goto error;
	}

	ctx->engine[ring->id].ringbuf = ringbuf;
	ctx->engine[ring->id].state = ctx_obj;

	if (ctx == ring->default_context)
		lrc_setup_hardware_status_page(ring, ctx_obj);
	else if (ring->id == RCS && !ctx->rcs_initialized) {
		if (ring->init_context) {
			ret = ring->init_context(ring, ctx);
			if (ret) {
				DRM_ERROR("ring init context: %d\n", ret);
				ctx->engine[ring->id].ringbuf = NULL;
				ctx->engine[ring->id].state = NULL;
				goto error;
			}
		}

		ctx->rcs_initialized = true;
	}

	return 0;

error:
	if (is_global_default_ctx)
		intel_unpin_ringbuffer_obj(ringbuf);
error_destroy_rbuf:
	intel_destroy_ringbuffer_obj(ringbuf);
error_free_rbuf:
	kfree(ringbuf);
error_unpin_ctx:
	if (is_global_default_ctx)
		i915_gem_object_ggtt_unpin(ctx_obj);
	drm_gem_object_unreference(&ctx_obj->base);
	return ret;
}

void intel_lr_context_reset(struct drm_device *dev,
			struct intel_context *ctx)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_engine_cs *ring;
	int i;

	for_each_ring(ring, dev_priv, i) {
		struct drm_i915_gem_object *ctx_obj =
				ctx->engine[ring->id].state;
		struct intel_ringbuffer *ringbuf =
				ctx->engine[ring->id].ringbuf;
		uint32_t *reg_state;
		struct page *page;

		if (!ctx_obj)
			continue;

		if (i915_gem_object_get_pages(ctx_obj)) {
			WARN(1, "Failed get_pages for context obj\n");
			continue;
		}
		page = i915_gem_object_get_page(ctx_obj, 1);
		reg_state = kmap_atomic(page);

		reg_state[CTX_RING_HEAD+1] = 0;
		reg_state[CTX_RING_TAIL+1] = 0;

		kunmap_atomic(reg_state);

		ringbuf->head = 0;
		ringbuf->tail = 0;
	}
}