summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/panthor/panthor_mmu.c
blob: bbc12728437f1365472b7f572f3d21fefcdd337e (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
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
// SPDX-License-Identifier: GPL-2.0 or MIT
/* Copyright 2019 Linaro, Ltd, Rob Herring <robh@kernel.org> */
/* Copyright 2023 Collabora ltd. */

#include <drm/drm_debugfs.h>
#include <drm/drm_drv.h>
#include <drm/drm_exec.h>
#include <drm/drm_gpuvm.h>
#include <drm/drm_managed.h>
#include <drm/gpu_scheduler.h>
#include <drm/panthor_drm.h>

#include <linux/atomic.h>
#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/io-pgtable.h>
#include <linux/iommu.h>
#include <linux/kmemleak.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/shmem_fs.h>
#include <linux/sizes.h>

#include "panthor_device.h"
#include "panthor_gem.h"
#include "panthor_heap.h"
#include "panthor_mmu.h"
#include "panthor_regs.h"
#include "panthor_sched.h"

#define MAX_AS_SLOTS			32

struct panthor_vm;

/**
 * struct panthor_as_slot - Address space slot
 */
struct panthor_as_slot {
	/** @vm: VM bound to this slot. NULL is no VM is bound. */
	struct panthor_vm *vm;
};

/**
 * struct panthor_mmu - MMU related data
 */
struct panthor_mmu {
	/** @irq: The MMU irq. */
	struct panthor_irq irq;

	/** @as: Address space related fields.
	 *
	 * The GPU has a limited number of address spaces (AS) slots, forcing
	 * us to re-assign them to re-assign slots on-demand.
	 */
	struct {
		/** @slots_lock: Lock protecting access to all other AS fields. */
		struct mutex slots_lock;

		/** @alloc_mask: Bitmask encoding the allocated slots. */
		unsigned long alloc_mask;

		/** @faulty_mask: Bitmask encoding the faulty slots. */
		unsigned long faulty_mask;

		/** @slots: VMs currently bound to the AS slots. */
		struct panthor_as_slot slots[MAX_AS_SLOTS];

		/**
		 * @lru_list: List of least recently used VMs.
		 *
		 * We use this list to pick a VM to evict when all slots are
		 * used.
		 *
		 * There should be no more active VMs than there are AS slots,
		 * so this LRU is just here to keep VMs bound until there's
		 * a need to release a slot, thus avoid unnecessary TLB/cache
		 * flushes.
		 */
		struct list_head lru_list;
	} as;

	/** @vm: VMs management fields */
	struct {
		/** @lock: Lock protecting access to list. */
		struct mutex lock;

		/** @list: List containing all VMs. */
		struct list_head list;

		/** @reset_in_progress: True if a reset is in progress. */
		bool reset_in_progress;

		/** @wq: Workqueue used for the VM_BIND queues. */
		struct workqueue_struct *wq;
	} vm;
};

/**
 * struct panthor_vm_pool - VM pool object
 */
struct panthor_vm_pool {
	/** @xa: Array used for VM handle tracking. */
	struct xarray xa;
};

/**
 * struct panthor_vma - GPU mapping object
 *
 * This is used to track GEM mappings in GPU space.
 */
struct panthor_vma {
	/** @base: Inherits from drm_gpuva. */
	struct drm_gpuva base;

	/** @node: Used to implement deferred release of VMAs. */
	struct list_head node;

	/**
	 * @flags: Combination of drm_panthor_vm_bind_op_flags.
	 *
	 * Only map related flags are accepted.
	 */
	u32 flags;
};

/**
 * struct panthor_vm_op_ctx - VM operation context
 *
 * With VM operations potentially taking place in a dma-signaling path, we
 * need to make sure everything that might require resource allocation is
 * pre-allocated upfront. This is what this operation context is far.
 *
 * We also collect resources that have been freed, so we can release them
 * asynchronously, and let the VM_BIND scheduler process the next VM_BIND
 * request.
 */
struct panthor_vm_op_ctx {
	/** @rsvd_page_tables: Pages reserved for the MMU page table update. */
	struct {
		/** @count: Number of pages reserved. */
		u32 count;

		/** @ptr: Point to the first unused page in the @pages table. */
		u32 ptr;

		/**
		 * @page: Array of pages that can be used for an MMU page table update.
		 *
		 * After an VM operation, there might be free pages left in this array.
		 * They should be returned to the pt_cache as part of the op_ctx cleanup.
		 */
		void **pages;
	} rsvd_page_tables;

	/**
	 * @preallocated_vmas: Pre-allocated VMAs to handle the remap case.
	 *
	 * Partial unmap requests or map requests overlapping existing mappings will
	 * trigger a remap call, which need to register up to three panthor_vma objects
	 * (one for the new mapping, and two for the previous and next mappings).
	 */
	struct panthor_vma *preallocated_vmas[3];

	/** @flags: Combination of drm_panthor_vm_bind_op_flags. */
	u32 flags;

	/** @va: Virtual range targeted by the VM operation. */
	struct {
		/** @addr: Start address. */
		u64 addr;

		/** @range: Range size. */
		u64 range;
	} va;

	/**
	 * @returned_vmas: List of panthor_vma objects returned after a VM operation.
	 *
	 * For unmap operations, this will contain all VMAs that were covered by the
	 * specified VA range.
	 *
	 * For map operations, this will contain all VMAs that previously mapped to
	 * the specified VA range.
	 *
	 * Those VMAs, and the resources they point to will be released as part of
	 * the op_ctx cleanup operation.
	 */
	struct list_head returned_vmas;

	/** @map: Fields specific to a map operation. */
	struct {
		/** @vm_bo: Buffer object to map. */
		struct drm_gpuvm_bo *vm_bo;

		/** @bo_offset: Offset in the buffer object. */
		u64 bo_offset;

		/**
		 * @sgt: sg-table pointing to pages backing the GEM object.
		 *
		 * This is gathered at job creation time, such that we don't have
		 * to allocate in ::run_job().
		 */
		struct sg_table *sgt;

		/**
		 * @new_vma: The new VMA object that will be inserted to the VA tree.
		 */
		struct panthor_vma *new_vma;
	} map;
};

/**
 * struct panthor_vm - VM object
 *
 * A VM is an object representing a GPU (or MCU) virtual address space.
 * It embeds the MMU page table for this address space, a tree containing
 * all the virtual mappings of GEM objects, and other things needed to manage
 * the VM.
 *
 * Except for the MCU VM, which is managed by the kernel, all other VMs are
 * created by userspace and mostly managed by userspace, using the
 * %DRM_IOCTL_PANTHOR_VM_BIND ioctl.
 *
 * A portion of the virtual address space is reserved for kernel objects,
 * like heap chunks, and userspace gets to decide how much of the virtual
 * address space is left to the kernel (half of the virtual address space
 * by default).
 */
struct panthor_vm {
	/**
	 * @base: Inherit from drm_gpuvm.
	 *
	 * We delegate all the VA management to the common drm_gpuvm framework
	 * and only implement hooks to update the MMU page table.
	 */
	struct drm_gpuvm base;

	/**
	 * @sched: Scheduler used for asynchronous VM_BIND request.
	 *
	 * We use a 1:1 scheduler here.
	 */
	struct drm_gpu_scheduler sched;

	/**
	 * @entity: Scheduling entity representing the VM_BIND queue.
	 *
	 * There's currently one bind queue per VM. It doesn't make sense to
	 * allow more given the VM operations are serialized anyway.
	 */
	struct drm_sched_entity entity;

	/** @ptdev: Device. */
	struct panthor_device *ptdev;

	/** @memattr: Value to program to the AS_MEMATTR register. */
	u64 memattr;

	/** @pgtbl_ops: Page table operations. */
	struct io_pgtable_ops *pgtbl_ops;

	/** @root_page_table: Stores the root page table pointer. */
	void *root_page_table;

	/**
	 * @op_lock: Lock used to serialize operations on a VM.
	 *
	 * The serialization of jobs queued to the VM_BIND queue is already
	 * taken care of by drm_sched, but we need to serialize synchronous
	 * and asynchronous VM_BIND request. This is what this lock is for.
	 */
	struct mutex op_lock;

	/**
	 * @op_ctx: The context attached to the currently executing VM operation.
	 *
	 * NULL when no operation is in progress.
	 */
	struct panthor_vm_op_ctx *op_ctx;

	/**
	 * @mm: Memory management object representing the auto-VA/kernel-VA.
	 *
	 * Used to auto-allocate VA space for kernel-managed objects (tiler
	 * heaps, ...).
	 *
	 * For the MCU VM, this is managing the VA range that's used to map
	 * all shared interfaces.
	 *
	 * For user VMs, the range is specified by userspace, and must not
	 * exceed half of the VA space addressable.
	 */
	struct drm_mm mm;

	/** @mm_lock: Lock protecting the @mm field. */
	struct mutex mm_lock;

	/** @kernel_auto_va: Automatic VA-range for kernel BOs. */
	struct {
		/** @start: Start of the automatic VA-range for kernel BOs. */
		u64 start;

		/** @size: Size of the automatic VA-range for kernel BOs. */
		u64 end;
	} kernel_auto_va;

	/** @as: Address space related fields. */
	struct {
		/**
		 * @id: ID of the address space this VM is bound to.
		 *
		 * A value of -1 means the VM is inactive/not bound.
		 */
		int id;

		/** @active_cnt: Number of active users of this VM. */
		refcount_t active_cnt;

		/**
		 * @lru_node: Used to instead the VM in the panthor_mmu::as::lru_list.
		 *
		 * Active VMs should not be inserted in the LRU list.
		 */
		struct list_head lru_node;
	} as;

	/**
	 * @heaps: Tiler heap related fields.
	 */
	struct {
		/**
		 * @pool: The heap pool attached to this VM.
		 *
		 * Will stay NULL until someone creates a heap context on this VM.
		 */
		struct panthor_heap_pool *pool;

		/** @lock: Lock used to protect access to @pool. */
		struct mutex lock;
	} heaps;

	/** @node: Used to insert the VM in the panthor_mmu::vm::list. */
	struct list_head node;

	/** @for_mcu: True if this is the MCU VM. */
	bool for_mcu;

	/**
	 * @destroyed: True if the VM was destroyed.
	 *
	 * No further bind requests should be queued to a destroyed VM.
	 */
	bool destroyed;

	/**
	 * @unusable: True if the VM has turned unusable because something
	 * bad happened during an asynchronous request.
	 *
	 * We don't try to recover from such failures, because this implies
	 * informing userspace about the specific operation that failed, and
	 * hoping the userspace driver can replay things from there. This all
	 * sounds very complicated for little gain.
	 *
	 * Instead, we should just flag the VM as unusable, and fail any
	 * further request targeting this VM.
	 *
	 * We also provide a way to query a VM state, so userspace can destroy
	 * it and create a new one.
	 *
	 * As an analogy, this would be mapped to a VK_ERROR_DEVICE_LOST
	 * situation, where the logical device needs to be re-created.
	 */
	bool unusable;

	/**
	 * @unhandled_fault: Unhandled fault happened.
	 *
	 * This should be reported to the scheduler, and the queue/group be
	 * flagged as faulty as a result.
	 */
	bool unhandled_fault;
};

/**
 * struct panthor_vm_bind_job - VM bind job
 */
struct panthor_vm_bind_job {
	/** @base: Inherit from drm_sched_job. */
	struct drm_sched_job base;

	/** @refcount: Reference count. */
	struct kref refcount;

	/** @cleanup_op_ctx_work: Work used to cleanup the VM operation context. */
	struct work_struct cleanup_op_ctx_work;

	/** @vm: VM targeted by the VM operation. */
	struct panthor_vm *vm;

	/** @ctx: Operation context. */
	struct panthor_vm_op_ctx ctx;
};

/**
 * @pt_cache: Cache used to allocate MMU page tables.
 *
 * The pre-allocation pattern forces us to over-allocate to plan for
 * the worst case scenario, and return the pages we didn't use.
 *
 * Having a kmem_cache allows us to speed allocations.
 */
static struct kmem_cache *pt_cache;

/**
 * alloc_pt() - Custom page table allocator
 * @cookie: Cookie passed at page table allocation time.
 * @size: Size of the page table. This size should be fixed,
 * and determined at creation time based on the granule size.
 * @gfp: GFP flags.
 *
 * We want a custom allocator so we can use a cache for page table
 * allocations and amortize the cost of the over-reservation that's
 * done to allow asynchronous VM operations.
 *
 * Return: non-NULL on success, NULL if the allocation failed for any
 * reason.
 */
static void *alloc_pt(void *cookie, size_t size, gfp_t gfp)
{
	struct panthor_vm *vm = cookie;
	void *page;

	/* Allocation of the root page table happening during init. */
	if (unlikely(!vm->root_page_table)) {
		struct page *p;

		drm_WARN_ON(&vm->ptdev->base, vm->op_ctx);
		p = alloc_pages_node(dev_to_node(vm->ptdev->base.dev),
				     gfp | __GFP_ZERO, get_order(size));
		page = p ? page_address(p) : NULL;
		vm->root_page_table = page;
		return page;
	}

	/* We're not supposed to have anything bigger than 4k here, because we picked a
	 * 4k granule size at init time.
	 */
	if (drm_WARN_ON(&vm->ptdev->base, size != SZ_4K))
		return NULL;

	/* We must have some op_ctx attached to the VM and it must have at least one
	 * free page.
	 */
	if (drm_WARN_ON(&vm->ptdev->base, !vm->op_ctx) ||
	    drm_WARN_ON(&vm->ptdev->base,
			vm->op_ctx->rsvd_page_tables.ptr >= vm->op_ctx->rsvd_page_tables.count))
		return NULL;

	page = vm->op_ctx->rsvd_page_tables.pages[vm->op_ctx->rsvd_page_tables.ptr++];
	memset(page, 0, SZ_4K);

	/* Page table entries don't use virtual addresses, which trips out
	 * kmemleak. kmemleak_alloc_phys() might work, but physical addresses
	 * are mixed with other fields, and I fear kmemleak won't detect that
	 * either.
	 *
	 * Let's just ignore memory passed to the page-table driver for now.
	 */
	kmemleak_ignore(page);
	return page;
}

/**
 * @free_pt() - Custom page table free function
 * @cookie: Cookie passed at page table allocation time.
 * @data: Page table to free.
 * @size: Size of the page table. This size should be fixed,
 * and determined at creation time based on the granule size.
 */
static void free_pt(void *cookie, void *data, size_t size)
{
	struct panthor_vm *vm = cookie;

	if (unlikely(vm->root_page_table == data)) {
		free_pages((unsigned long)data, get_order(size));
		vm->root_page_table = NULL;
		return;
	}

	if (drm_WARN_ON(&vm->ptdev->base, size != SZ_4K))
		return;

	/* Return the page to the pt_cache. */
	kmem_cache_free(pt_cache, data);
}

static int wait_ready(struct panthor_device *ptdev, u32 as_nr)
{
	int ret;
	u32 val;

	/* Wait for the MMU status to indicate there is no active command, in
	 * case one is pending.
	 */
	ret = readl_relaxed_poll_timeout_atomic(ptdev->iomem + AS_STATUS(as_nr),
						val, !(val & AS_STATUS_AS_ACTIVE),
						10, 100000);

	if (ret) {
		panthor_device_schedule_reset(ptdev);
		drm_err(&ptdev->base, "AS_ACTIVE bit stuck\n");
	}

	return ret;
}

static int write_cmd(struct panthor_device *ptdev, u32 as_nr, u32 cmd)
{
	int status;

	/* write AS_COMMAND when MMU is ready to accept another command */
	status = wait_ready(ptdev, as_nr);
	if (!status)
		gpu_write(ptdev, AS_COMMAND(as_nr), cmd);

	return status;
}

static void lock_region(struct panthor_device *ptdev, u32 as_nr,
			u64 region_start, u64 size)
{
	u8 region_width;
	u64 region;
	u64 region_end = region_start + size;

	if (!size)
		return;

	/*
	 * The locked region is a naturally aligned power of 2 block encoded as
	 * log2 minus(1).
	 * Calculate the desired start/end and look for the highest bit which
	 * differs. The smallest naturally aligned block must include this bit
	 * change, the desired region starts with this bit (and subsequent bits)
	 * zeroed and ends with the bit (and subsequent bits) set to one.
	 */
	region_width = max(fls64(region_start ^ (region_end - 1)),
			   const_ilog2(AS_LOCK_REGION_MIN_SIZE)) - 1;

	/*
	 * Mask off the low bits of region_start (which would be ignored by
	 * the hardware anyway)
	 */
	region_start &= GENMASK_ULL(63, region_width);

	region = region_width | region_start;

	/* Lock the region that needs to be updated */
	gpu_write(ptdev, AS_LOCKADDR_LO(as_nr), lower_32_bits(region));
	gpu_write(ptdev, AS_LOCKADDR_HI(as_nr), upper_32_bits(region));
	write_cmd(ptdev, as_nr, AS_COMMAND_LOCK);
}

static int mmu_hw_do_operation_locked(struct panthor_device *ptdev, int as_nr,
				      u64 iova, u64 size, u32 op)
{
	lockdep_assert_held(&ptdev->mmu->as.slots_lock);

	if (as_nr < 0)
		return 0;

	/*
	 * If the AS number is greater than zero, then we can be sure
	 * the device is up and running, so we don't need to explicitly
	 * power it up
	 */

	if (op != AS_COMMAND_UNLOCK)
		lock_region(ptdev, as_nr, iova, size);

	/* Run the MMU operation */
	write_cmd(ptdev, as_nr, op);

	/* Wait for the flush to complete */
	return wait_ready(ptdev, as_nr);
}

static int mmu_hw_do_operation(struct panthor_vm *vm,
			       u64 iova, u64 size, u32 op)
{
	struct panthor_device *ptdev = vm->ptdev;
	int ret;

	mutex_lock(&ptdev->mmu->as.slots_lock);
	ret = mmu_hw_do_operation_locked(ptdev, vm->as.id, iova, size, op);
	mutex_unlock(&ptdev->mmu->as.slots_lock);

	return ret;
}

static int panthor_mmu_as_enable(struct panthor_device *ptdev, u32 as_nr,
				 u64 transtab, u64 transcfg, u64 memattr)
{
	int ret;

	ret = mmu_hw_do_operation_locked(ptdev, as_nr, 0, ~0ULL, AS_COMMAND_FLUSH_MEM);
	if (ret)
		return ret;

	gpu_write(ptdev, AS_TRANSTAB_LO(as_nr), lower_32_bits(transtab));
	gpu_write(ptdev, AS_TRANSTAB_HI(as_nr), upper_32_bits(transtab));

	gpu_write(ptdev, AS_MEMATTR_LO(as_nr), lower_32_bits(memattr));
	gpu_write(ptdev, AS_MEMATTR_HI(as_nr), upper_32_bits(memattr));

	gpu_write(ptdev, AS_TRANSCFG_LO(as_nr), lower_32_bits(transcfg));
	gpu_write(ptdev, AS_TRANSCFG_HI(as_nr), upper_32_bits(transcfg));

	return write_cmd(ptdev, as_nr, AS_COMMAND_UPDATE);
}

static int panthor_mmu_as_disable(struct panthor_device *ptdev, u32 as_nr)
{
	int ret;

	ret = mmu_hw_do_operation_locked(ptdev, as_nr, 0, ~0ULL, AS_COMMAND_FLUSH_MEM);
	if (ret)
		return ret;

	gpu_write(ptdev, AS_TRANSTAB_LO(as_nr), 0);
	gpu_write(ptdev, AS_TRANSTAB_HI(as_nr), 0);

	gpu_write(ptdev, AS_MEMATTR_LO(as_nr), 0);
	gpu_write(ptdev, AS_MEMATTR_HI(as_nr), 0);

	gpu_write(ptdev, AS_TRANSCFG_LO(as_nr), AS_TRANSCFG_ADRMODE_UNMAPPED);
	gpu_write(ptdev, AS_TRANSCFG_HI(as_nr), 0);

	return write_cmd(ptdev, as_nr, AS_COMMAND_UPDATE);
}

static u32 panthor_mmu_fault_mask(struct panthor_device *ptdev, u32 value)
{
	/* Bits 16 to 31 mean REQ_COMPLETE. */
	return value & GENMASK(15, 0);
}

static u32 panthor_mmu_as_fault_mask(struct panthor_device *ptdev, u32 as)
{
	return BIT(as);
}

/**
 * panthor_vm_has_unhandled_faults() - Check if a VM has unhandled faults
 * @vm: VM to check.
 *
 * Return: true if the VM has unhandled faults, false otherwise.
 */
bool panthor_vm_has_unhandled_faults(struct panthor_vm *vm)
{
	return vm->unhandled_fault;
}

/**
 * panthor_vm_is_unusable() - Check if the VM is still usable
 * @vm: VM to check.
 *
 * Return: true if the VM is unusable, false otherwise.
 */
bool panthor_vm_is_unusable(struct panthor_vm *vm)
{
	return vm->unusable;
}

static void panthor_vm_release_as_locked(struct panthor_vm *vm)
{
	struct panthor_device *ptdev = vm->ptdev;

	lockdep_assert_held(&ptdev->mmu->as.slots_lock);

	if (drm_WARN_ON(&ptdev->base, vm->as.id < 0))
		return;

	ptdev->mmu->as.slots[vm->as.id].vm = NULL;
	clear_bit(vm->as.id, &ptdev->mmu->as.alloc_mask);
	refcount_set(&vm->as.active_cnt, 0);
	list_del_init(&vm->as.lru_node);
	vm->as.id = -1;
}

/**
 * panthor_vm_active() - Flag a VM as active
 * @VM: VM to flag as active.
 *
 * Assigns an address space to a VM so it can be used by the GPU/MCU.
 *
 * Return: 0 on success, a negative error code otherwise.
 */
int panthor_vm_active(struct panthor_vm *vm)
{
	struct panthor_device *ptdev = vm->ptdev;
	u32 va_bits = GPU_MMU_FEATURES_VA_BITS(ptdev->gpu_info.mmu_features);
	struct io_pgtable_cfg *cfg = &io_pgtable_ops_to_pgtable(vm->pgtbl_ops)->cfg;
	int ret = 0, as, cookie;
	u64 transtab, transcfg;

	if (!drm_dev_enter(&ptdev->base, &cookie))
		return -ENODEV;

	if (refcount_inc_not_zero(&vm->as.active_cnt))
		goto out_dev_exit;

	mutex_lock(&ptdev->mmu->as.slots_lock);

	if (refcount_inc_not_zero(&vm->as.active_cnt))
		goto out_unlock;

	as = vm->as.id;
	if (as >= 0) {
		/* Unhandled pagefault on this AS, the MMU was disabled. We need to
		 * re-enable the MMU after clearing+unmasking the AS interrupts.
		 */
		if (ptdev->mmu->as.faulty_mask & panthor_mmu_as_fault_mask(ptdev, as))
			goto out_enable_as;

		goto out_make_active;
	}

	/* Check for a free AS */
	if (vm->for_mcu) {
		drm_WARN_ON(&ptdev->base, ptdev->mmu->as.alloc_mask & BIT(0));
		as = 0;
	} else {
		as = ffz(ptdev->mmu->as.alloc_mask | BIT(0));
	}

	if (!(BIT(as) & ptdev->gpu_info.as_present)) {
		struct panthor_vm *lru_vm;

		lru_vm = list_first_entry_or_null(&ptdev->mmu->as.lru_list,
						  struct panthor_vm,
						  as.lru_node);
		if (drm_WARN_ON(&ptdev->base, !lru_vm)) {
			ret = -EBUSY;
			goto out_unlock;
		}

		drm_WARN_ON(&ptdev->base, refcount_read(&lru_vm->as.active_cnt));
		as = lru_vm->as.id;
		panthor_vm_release_as_locked(lru_vm);
	}

	/* Assign the free or reclaimed AS to the FD */
	vm->as.id = as;
	set_bit(as, &ptdev->mmu->as.alloc_mask);
	ptdev->mmu->as.slots[as].vm = vm;

out_enable_as:
	transtab = cfg->arm_lpae_s1_cfg.ttbr;
	transcfg = AS_TRANSCFG_PTW_MEMATTR_WB |
		   AS_TRANSCFG_PTW_RA |
		   AS_TRANSCFG_ADRMODE_AARCH64_4K |
		   AS_TRANSCFG_INA_BITS(55 - va_bits);
	if (ptdev->coherent)
		transcfg |= AS_TRANSCFG_PTW_SH_OS;

	/* If the VM is re-activated, we clear the fault. */
	vm->unhandled_fault = false;

	/* Unhandled pagefault on this AS, clear the fault and re-enable interrupts
	 * before enabling the AS.
	 */
	if (ptdev->mmu->as.faulty_mask & panthor_mmu_as_fault_mask(ptdev, as)) {
		gpu_write(ptdev, MMU_INT_CLEAR, panthor_mmu_as_fault_mask(ptdev, as));
		ptdev->mmu->as.faulty_mask &= ~panthor_mmu_as_fault_mask(ptdev, as);
		gpu_write(ptdev, MMU_INT_MASK, ~ptdev->mmu->as.faulty_mask);
	}

	ret = panthor_mmu_as_enable(vm->ptdev, vm->as.id, transtab, transcfg, vm->memattr);

out_make_active:
	if (!ret) {
		refcount_set(&vm->as.active_cnt, 1);
		list_del_init(&vm->as.lru_node);
	}

out_unlock:
	mutex_unlock(&ptdev->mmu->as.slots_lock);

out_dev_exit:
	drm_dev_exit(cookie);
	return ret;
}

/**
 * panthor_vm_idle() - Flag a VM idle
 * @VM: VM to flag as idle.
 *
 * When we know the GPU is done with the VM (no more jobs to process),
 * we can relinquish the AS slot attached to this VM, if any.
 *
 * We don't release the slot immediately, but instead place the VM in
 * the LRU list, so it can be evicted if another VM needs an AS slot.
 * This way, VMs keep attached to the AS they were given until we run
 * out of free slot, limiting the number of MMU operations (TLB flush
 * and other AS updates).
 */
void panthor_vm_idle(struct panthor_vm *vm)
{
	struct panthor_device *ptdev = vm->ptdev;

	if (!refcount_dec_and_mutex_lock(&vm->as.active_cnt, &ptdev->mmu->as.slots_lock))
		return;

	if (!drm_WARN_ON(&ptdev->base, vm->as.id == -1 || !list_empty(&vm->as.lru_node)))
		list_add_tail(&vm->as.lru_node, &ptdev->mmu->as.lru_list);

	refcount_set(&vm->as.active_cnt, 0);
	mutex_unlock(&ptdev->mmu->as.slots_lock);
}

static void panthor_vm_stop(struct panthor_vm *vm)
{
	drm_sched_stop(&vm->sched, NULL);
}

static void panthor_vm_start(struct panthor_vm *vm)
{
	drm_sched_start(&vm->sched);
}

/**
 * panthor_vm_as() - Get the AS slot attached to a VM
 * @vm: VM to get the AS slot of.
 *
 * Return: -1 if the VM is not assigned an AS slot yet, >= 0 otherwise.
 */
int panthor_vm_as(struct panthor_vm *vm)
{
	return vm->as.id;
}

static size_t get_pgsize(u64 addr, size_t size, size_t *count)
{
	/*
	 * io-pgtable only operates on multiple pages within a single table
	 * entry, so we need to split at boundaries of the table size, i.e.
	 * the next block size up. The distance from address A to the next
	 * boundary of block size B is logically B - A % B, but in unsigned
	 * two's complement where B is a power of two we get the equivalence
	 * B - A % B == (B - A) % B == (n * B - A) % B, and choose n = 0 :)
	 */
	size_t blk_offset = -addr % SZ_2M;

	if (blk_offset || size < SZ_2M) {
		*count = min_not_zero(blk_offset, size) / SZ_4K;
		return SZ_4K;
	}
	blk_offset = -addr % SZ_1G ?: SZ_1G;
	*count = min(blk_offset, size) / SZ_2M;
	return SZ_2M;
}

static int panthor_vm_flush_range(struct panthor_vm *vm, u64 iova, u64 size)
{
	struct panthor_device *ptdev = vm->ptdev;
	int ret = 0, cookie;

	if (vm->as.id < 0)
		return 0;

	/* If the device is unplugged, we just silently skip the flush. */
	if (!drm_dev_enter(&ptdev->base, &cookie))
		return 0;

	ret = mmu_hw_do_operation(vm, iova, size, AS_COMMAND_FLUSH_PT);

	drm_dev_exit(cookie);
	return ret;
}

/**
 * panthor_vm_flush_all() - Flush L2 caches for the entirety of a VM's AS
 * @vm: VM whose cache to flush
 *
 * Return: 0 on success, a negative error code if flush failed.
 */
int panthor_vm_flush_all(struct panthor_vm *vm)
{
	return panthor_vm_flush_range(vm, vm->base.mm_start, vm->base.mm_range);
}

static int panthor_vm_unmap_pages(struct panthor_vm *vm, u64 iova, u64 size)
{
	struct panthor_device *ptdev = vm->ptdev;
	struct io_pgtable_ops *ops = vm->pgtbl_ops;
	u64 offset = 0;

	drm_dbg(&ptdev->base, "unmap: as=%d, iova=%llx, len=%llx", vm->as.id, iova, size);

	while (offset < size) {
		size_t unmapped_sz = 0, pgcount;
		size_t pgsize = get_pgsize(iova + offset, size - offset, &pgcount);

		unmapped_sz = ops->unmap_pages(ops, iova + offset, pgsize, pgcount, NULL);

		if (drm_WARN_ON(&ptdev->base, unmapped_sz != pgsize * pgcount)) {
			drm_err(&ptdev->base, "failed to unmap range %llx-%llx (requested range %llx-%llx)\n",
				iova + offset + unmapped_sz,
				iova + offset + pgsize * pgcount,
				iova, iova + size);
			panthor_vm_flush_range(vm, iova, offset + unmapped_sz);
			return  -EINVAL;
		}
		offset += unmapped_sz;
	}

	return panthor_vm_flush_range(vm, iova, size);
}

static int
panthor_vm_map_pages(struct panthor_vm *vm, u64 iova, int prot,
		     struct sg_table *sgt, u64 offset, u64 size)
{
	struct panthor_device *ptdev = vm->ptdev;
	unsigned int count;
	struct scatterlist *sgl;
	struct io_pgtable_ops *ops = vm->pgtbl_ops;
	u64 start_iova = iova;
	int ret;

	if (!size)
		return 0;

	for_each_sgtable_dma_sg(sgt, sgl, count) {
		dma_addr_t paddr = sg_dma_address(sgl);
		size_t len = sg_dma_len(sgl);

		if (len <= offset) {
			offset -= len;
			continue;
		}

		paddr += offset;
		len -= offset;
		len = min_t(size_t, len, size);
		size -= len;

		drm_dbg(&ptdev->base, "map: as=%d, iova=%llx, paddr=%pad, len=%zx",
			vm->as.id, iova, &paddr, len);

		while (len) {
			size_t pgcount, mapped = 0;
			size_t pgsize = get_pgsize(iova | paddr, len, &pgcount);

			ret = ops->map_pages(ops, iova, paddr, pgsize, pgcount, prot,
					     GFP_KERNEL, &mapped);
			iova += mapped;
			paddr += mapped;
			len -= mapped;

			if (drm_WARN_ON(&ptdev->base, !ret && !mapped))
				ret = -ENOMEM;

			if (ret) {
				/* If something failed, unmap what we've already mapped before
				 * returning. The unmap call is not supposed to fail.
				 */
				drm_WARN_ON(&ptdev->base,
					    panthor_vm_unmap_pages(vm, start_iova,
								   iova - start_iova));
				return ret;
			}
		}

		if (!size)
			break;
	}

	return panthor_vm_flush_range(vm, start_iova, iova - start_iova);
}

static int flags_to_prot(u32 flags)
{
	int prot = 0;

	if (flags & DRM_PANTHOR_VM_BIND_OP_MAP_NOEXEC)
		prot |= IOMMU_NOEXEC;

	if (!(flags & DRM_PANTHOR_VM_BIND_OP_MAP_UNCACHED))
		prot |= IOMMU_CACHE;

	if (flags & DRM_PANTHOR_VM_BIND_OP_MAP_READONLY)
		prot |= IOMMU_READ;
	else
		prot |= IOMMU_READ | IOMMU_WRITE;

	return prot;
}

/**
 * panthor_vm_alloc_va() - Allocate a region in the auto-va space
 * @VM: VM to allocate a region on.
 * @va: start of the VA range. Can be PANTHOR_VM_KERNEL_AUTO_VA if the user
 * wants the VA to be automatically allocated from the auto-VA range.
 * @size: size of the VA range.
 * @va_node: drm_mm_node to initialize. Must be zero-initialized.
 *
 * Some GPU objects, like heap chunks, are fully managed by the kernel and
 * need to be mapped to the userspace VM, in the region reserved for kernel
 * objects.
 *
 * This function takes care of allocating a region in the kernel auto-VA space.
 *
 * Return: 0 on success, an error code otherwise.
 */
int
panthor_vm_alloc_va(struct panthor_vm *vm, u64 va, u64 size,
		    struct drm_mm_node *va_node)
{
	int ret;

	if (!size || (size & ~PAGE_MASK))
		return -EINVAL;

	if (va != PANTHOR_VM_KERNEL_AUTO_VA && (va & ~PAGE_MASK))
		return -EINVAL;

	mutex_lock(&vm->mm_lock);
	if (va != PANTHOR_VM_KERNEL_AUTO_VA) {
		va_node->start = va;
		va_node->size = size;
		ret = drm_mm_reserve_node(&vm->mm, va_node);
	} else {
		ret = drm_mm_insert_node_in_range(&vm->mm, va_node, size,
						  size >= SZ_2M ? SZ_2M : SZ_4K,
						  0, vm->kernel_auto_va.start,
						  vm->kernel_auto_va.end,
						  DRM_MM_INSERT_BEST);
	}
	mutex_unlock(&vm->mm_lock);

	return ret;
}

/**
 * panthor_vm_free_va() - Free a region allocated with panthor_vm_alloc_va()
 * @VM: VM to free the region on.
 * @va_node: Memory node representing the region to free.
 */
void panthor_vm_free_va(struct panthor_vm *vm, struct drm_mm_node *va_node)
{
	mutex_lock(&vm->mm_lock);
	drm_mm_remove_node(va_node);
	mutex_unlock(&vm->mm_lock);
}

static void panthor_vm_bo_put(struct drm_gpuvm_bo *vm_bo)
{
	struct panthor_gem_object *bo = to_panthor_bo(vm_bo->obj);
	struct drm_gpuvm *vm = vm_bo->vm;
	bool unpin;

	/* We must retain the GEM before calling drm_gpuvm_bo_put(),
	 * otherwise the mutex might be destroyed while we hold it.
	 * Same goes for the VM, since we take the VM resv lock.
	 */
	drm_gem_object_get(&bo->base.base);
	drm_gpuvm_get(vm);

	/* We take the resv lock to protect against concurrent accesses to the
	 * gpuvm evicted/extobj lists that are modified in
	 * drm_gpuvm_bo_destroy(), which is called if drm_gpuvm_bo_put()
	 * releases sthe last vm_bo reference.
	 * We take the BO GPUVA list lock to protect the vm_bo removal from the
	 * GEM vm_bo list.
	 */
	dma_resv_lock(drm_gpuvm_resv(vm), NULL);
	mutex_lock(&bo->gpuva_list_lock);
	unpin = drm_gpuvm_bo_put(vm_bo);
	mutex_unlock(&bo->gpuva_list_lock);
	dma_resv_unlock(drm_gpuvm_resv(vm));

	/* If the vm_bo object was destroyed, release the pin reference that
	 * was hold by this object.
	 */
	if (unpin && !bo->base.base.import_attach)
		drm_gem_shmem_unpin(&bo->base);

	drm_gpuvm_put(vm);
	drm_gem_object_put(&bo->base.base);
}

static void panthor_vm_cleanup_op_ctx(struct panthor_vm_op_ctx *op_ctx,
				      struct panthor_vm *vm)
{
	struct panthor_vma *vma, *tmp_vma;

	u32 remaining_pt_count = op_ctx->rsvd_page_tables.count -
				 op_ctx->rsvd_page_tables.ptr;

	if (remaining_pt_count) {
		kmem_cache_free_bulk(pt_cache, remaining_pt_count,
				     op_ctx->rsvd_page_tables.pages +
				     op_ctx->rsvd_page_tables.ptr);
	}

	kfree(op_ctx->rsvd_page_tables.pages);

	if (op_ctx->map.vm_bo)
		panthor_vm_bo_put(op_ctx->map.vm_bo);

	for (u32 i = 0; i < ARRAY_SIZE(op_ctx->preallocated_vmas); i++)
		kfree(op_ctx->preallocated_vmas[i]);

	list_for_each_entry_safe(vma, tmp_vma, &op_ctx->returned_vmas, node) {
		list_del(&vma->node);
		panthor_vm_bo_put(vma->base.vm_bo);
		kfree(vma);
	}
}

static struct panthor_vma *
panthor_vm_op_ctx_get_vma(struct panthor_vm_op_ctx *op_ctx)
{
	for (u32 i = 0; i < ARRAY_SIZE(op_ctx->preallocated_vmas); i++) {
		struct panthor_vma *vma = op_ctx->preallocated_vmas[i];

		if (vma) {
			op_ctx->preallocated_vmas[i] = NULL;
			return vma;
		}
	}

	return NULL;
}

static int
panthor_vm_op_ctx_prealloc_vmas(struct panthor_vm_op_ctx *op_ctx)
{
	u32 vma_count;

	switch (op_ctx->flags & DRM_PANTHOR_VM_BIND_OP_TYPE_MASK) {
	case DRM_PANTHOR_VM_BIND_OP_TYPE_MAP:
		/* One VMA for the new mapping, and two more VMAs for the remap case
		 * which might contain both a prev and next VA.
		 */
		vma_count = 3;
		break;

	case DRM_PANTHOR_VM_BIND_OP_TYPE_UNMAP:
		/* Partial unmaps might trigger a remap with either a prev or a next VA,
		 * but not both.
		 */
		vma_count = 1;
		break;

	default:
		return 0;
	}

	for (u32 i = 0; i < vma_count; i++) {
		struct panthor_vma *vma = kzalloc(sizeof(*vma), GFP_KERNEL);

		if (!vma)
			return -ENOMEM;

		op_ctx->preallocated_vmas[i] = vma;
	}

	return 0;
}

#define PANTHOR_VM_BIND_OP_MAP_FLAGS \
	(DRM_PANTHOR_VM_BIND_OP_MAP_READONLY | \
	 DRM_PANTHOR_VM_BIND_OP_MAP_NOEXEC | \
	 DRM_PANTHOR_VM_BIND_OP_MAP_UNCACHED | \
	 DRM_PANTHOR_VM_BIND_OP_TYPE_MASK)

static int panthor_vm_prepare_map_op_ctx(struct panthor_vm_op_ctx *op_ctx,
					 struct panthor_vm *vm,
					 struct panthor_gem_object *bo,
					 u64 offset,
					 u64 size, u64 va,
					 u32 flags)
{
	struct drm_gpuvm_bo *preallocated_vm_bo;
	struct sg_table *sgt = NULL;
	u64 pt_count;
	int ret;

	if (!bo)
		return -EINVAL;

	if ((flags & ~PANTHOR_VM_BIND_OP_MAP_FLAGS) ||
	    (flags & DRM_PANTHOR_VM_BIND_OP_TYPE_MASK) != DRM_PANTHOR_VM_BIND_OP_TYPE_MAP)
		return -EINVAL;

	/* Make sure the VA and size are aligned and in-bounds. */
	if (size > bo->base.base.size || offset > bo->base.base.size - size)
		return -EINVAL;

	/* If the BO has an exclusive VM attached, it can't be mapped to other VMs. */
	if (bo->exclusive_vm_root_gem &&
	    bo->exclusive_vm_root_gem != panthor_vm_root_gem(vm))
		return -EINVAL;

	memset(op_ctx, 0, sizeof(*op_ctx));
	INIT_LIST_HEAD(&op_ctx->returned_vmas);
	op_ctx->flags = flags;
	op_ctx->va.range = size;
	op_ctx->va.addr = va;

	ret = panthor_vm_op_ctx_prealloc_vmas(op_ctx);
	if (ret)
		goto err_cleanup;

	if (!bo->base.base.import_attach) {
		/* Pre-reserve the BO pages, so the map operation doesn't have to
		 * allocate.
		 */
		ret = drm_gem_shmem_pin(&bo->base);
		if (ret)
			goto err_cleanup;
	}

	sgt = drm_gem_shmem_get_pages_sgt(&bo->base);
	if (IS_ERR(sgt)) {
		if (!bo->base.base.import_attach)
			drm_gem_shmem_unpin(&bo->base);

		ret = PTR_ERR(sgt);
		goto err_cleanup;
	}

	op_ctx->map.sgt = sgt;

	preallocated_vm_bo = drm_gpuvm_bo_create(&vm->base, &bo->base.base);
	if (!preallocated_vm_bo) {
		if (!bo->base.base.import_attach)
			drm_gem_shmem_unpin(&bo->base);

		ret = -ENOMEM;
		goto err_cleanup;
	}

	mutex_lock(&bo->gpuva_list_lock);
	op_ctx->map.vm_bo = drm_gpuvm_bo_obtain_prealloc(preallocated_vm_bo);
	mutex_unlock(&bo->gpuva_list_lock);

	/* If the a vm_bo for this <VM,BO> combination exists, it already
	 * retains a pin ref, and we can release the one we took earlier.
	 *
	 * If our pre-allocated vm_bo is picked, it now retains the pin ref,
	 * which will be released in panthor_vm_bo_put().
	 */
	if (preallocated_vm_bo != op_ctx->map.vm_bo &&
	    !bo->base.base.import_attach)
		drm_gem_shmem_unpin(&bo->base);

	op_ctx->map.bo_offset = offset;

	/* L1, L2 and L3 page tables.
	 * We could optimize L3 allocation by iterating over the sgt and merging
	 * 2M contiguous blocks, but it's simpler to over-provision and return
	 * the pages if they're not used.
	 */
	pt_count = ((ALIGN(va + size, 1ull << 39) - ALIGN_DOWN(va, 1ull << 39)) >> 39) +
		   ((ALIGN(va + size, 1ull << 30) - ALIGN_DOWN(va, 1ull << 30)) >> 30) +
		   ((ALIGN(va + size, 1ull << 21) - ALIGN_DOWN(va, 1ull << 21)) >> 21);

	op_ctx->rsvd_page_tables.pages = kcalloc(pt_count,
						 sizeof(*op_ctx->rsvd_page_tables.pages),
						 GFP_KERNEL);
	if (!op_ctx->rsvd_page_tables.pages) {
		ret = -ENOMEM;
		goto err_cleanup;
	}

	ret = kmem_cache_alloc_bulk(pt_cache, GFP_KERNEL, pt_count,
				    op_ctx->rsvd_page_tables.pages);
	op_ctx->rsvd_page_tables.count = ret;
	if (ret != pt_count) {
		ret = -ENOMEM;
		goto err_cleanup;
	}

	/* Insert BO into the extobj list last, when we know nothing can fail. */
	dma_resv_lock(panthor_vm_resv(vm), NULL);
	drm_gpuvm_bo_extobj_add(op_ctx->map.vm_bo);
	dma_resv_unlock(panthor_vm_resv(vm));

	return 0;

err_cleanup:
	panthor_vm_cleanup_op_ctx(op_ctx, vm);
	return ret;
}

static int panthor_vm_prepare_unmap_op_ctx(struct panthor_vm_op_ctx *op_ctx,
					   struct panthor_vm *vm,
					   u64 va, u64 size)
{
	u32 pt_count = 0;
	int ret;

	memset(op_ctx, 0, sizeof(*op_ctx));
	INIT_LIST_HEAD(&op_ctx->returned_vmas);
	op_ctx->va.range = size;
	op_ctx->va.addr = va;
	op_ctx->flags = DRM_PANTHOR_VM_BIND_OP_TYPE_UNMAP;

	/* Pre-allocate L3 page tables to account for the split-2M-block
	 * situation on unmap.
	 */
	if (va != ALIGN(va, SZ_2M))
		pt_count++;

	if (va + size != ALIGN(va + size, SZ_2M) &&
	    ALIGN(va + size, SZ_2M) != ALIGN(va, SZ_2M))
		pt_count++;

	ret = panthor_vm_op_ctx_prealloc_vmas(op_ctx);
	if (ret)
		goto err_cleanup;

	if (pt_count) {
		op_ctx->rsvd_page_tables.pages = kcalloc(pt_count,
							 sizeof(*op_ctx->rsvd_page_tables.pages),
							 GFP_KERNEL);
		if (!op_ctx->rsvd_page_tables.pages) {
			ret = -ENOMEM;
			goto err_cleanup;
		}

		ret = kmem_cache_alloc_bulk(pt_cache, GFP_KERNEL, pt_count,
					    op_ctx->rsvd_page_tables.pages);
		if (ret != pt_count) {
			ret = -ENOMEM;
			goto err_cleanup;
		}
		op_ctx->rsvd_page_tables.count = pt_count;
	}

	return 0;

err_cleanup:
	panthor_vm_cleanup_op_ctx(op_ctx, vm);
	return ret;
}

static void panthor_vm_prepare_sync_only_op_ctx(struct panthor_vm_op_ctx *op_ctx,
						struct panthor_vm *vm)
{
	memset(op_ctx, 0, sizeof(*op_ctx));
	INIT_LIST_HEAD(&op_ctx->returned_vmas);
	op_ctx->flags = DRM_PANTHOR_VM_BIND_OP_TYPE_SYNC_ONLY;
}

/**
 * panthor_vm_get_bo_for_va() - Get the GEM object mapped at a virtual address
 * @vm: VM to look into.
 * @va: Virtual address to search for.
 * @bo_offset: Offset of the GEM object mapped at this virtual address.
 * Only valid on success.
 *
 * The object returned by this function might no longer be mapped when the
 * function returns. It's the caller responsibility to ensure there's no
 * concurrent map/unmap operations making the returned value invalid, or
 * make sure it doesn't matter if the object is no longer mapped.
 *
 * Return: A valid pointer on success, an ERR_PTR() otherwise.
 */
struct panthor_gem_object *
panthor_vm_get_bo_for_va(struct panthor_vm *vm, u64 va, u64 *bo_offset)
{
	struct panthor_gem_object *bo = ERR_PTR(-ENOENT);
	struct drm_gpuva *gpuva;
	struct panthor_vma *vma;

	/* Take the VM lock to prevent concurrent map/unmap operations. */
	mutex_lock(&vm->op_lock);
	gpuva = drm_gpuva_find_first(&vm->base, va, 1);
	vma = gpuva ? container_of(gpuva, struct panthor_vma, base) : NULL;
	if (vma && vma->base.gem.obj) {
		drm_gem_object_get(vma->base.gem.obj);
		bo = to_panthor_bo(vma->base.gem.obj);
		*bo_offset = vma->base.gem.offset + (va - vma->base.va.addr);
	}
	mutex_unlock(&vm->op_lock);

	return bo;
}

#define PANTHOR_VM_MIN_KERNEL_VA_SIZE	SZ_256M

static u64
panthor_vm_create_get_user_va_range(const struct drm_panthor_vm_create *args,
				    u64 full_va_range)
{
	u64 user_va_range;

	/* Make sure we have a minimum amount of VA space for kernel objects. */
	if (full_va_range < PANTHOR_VM_MIN_KERNEL_VA_SIZE)
		return 0;

	if (args->user_va_range) {
		/* Use the user provided value if != 0. */
		user_va_range = args->user_va_range;
	} else if (TASK_SIZE_OF(current) < full_va_range) {
		/* If the task VM size is smaller than the GPU VA range, pick this
		 * as our default user VA range, so userspace can CPU/GPU map buffers
		 * at the same address.
		 */
		user_va_range = TASK_SIZE_OF(current);
	} else {
		/* If the GPU VA range is smaller than the task VM size, we
		 * just have to live with the fact we won't be able to map
		 * all buffers at the same GPU/CPU address.
		 *
		 * If the GPU VA range is bigger than 4G (more than 32-bit of
		 * VA), we split the range in two, and assign half of it to
		 * the user and the other half to the kernel, if it's not, we
		 * keep the kernel VA space as small as possible.
		 */
		user_va_range = full_va_range > SZ_4G ?
				full_va_range / 2 :
				full_va_range - PANTHOR_VM_MIN_KERNEL_VA_SIZE;
	}

	if (full_va_range - PANTHOR_VM_MIN_KERNEL_VA_SIZE < user_va_range)
		user_va_range = full_va_range - PANTHOR_VM_MIN_KERNEL_VA_SIZE;

	return user_va_range;
}

#define PANTHOR_VM_CREATE_FLAGS		0

static int
panthor_vm_create_check_args(const struct panthor_device *ptdev,
			     const struct drm_panthor_vm_create *args,
			     u64 *kernel_va_start, u64 *kernel_va_range)
{
	u32 va_bits = GPU_MMU_FEATURES_VA_BITS(ptdev->gpu_info.mmu_features);
	u64 full_va_range = 1ull << va_bits;
	u64 user_va_range;

	if (args->flags & ~PANTHOR_VM_CREATE_FLAGS)
		return -EINVAL;

	user_va_range = panthor_vm_create_get_user_va_range(args, full_va_range);
	if (!user_va_range || (args->user_va_range && args->user_va_range > user_va_range))
		return -EINVAL;

	/* Pick a kernel VA range that's a power of two, to have a clear split. */
	*kernel_va_range = rounddown_pow_of_two(full_va_range - user_va_range);
	*kernel_va_start = full_va_range - *kernel_va_range;
	return 0;
}

/*
 * Only 32 VMs per open file. If that becomes a limiting factor, we can
 * increase this number.
 */
#define PANTHOR_MAX_VMS_PER_FILE	32

/**
 * panthor_vm_pool_create_vm() - Create a VM
 * @pool: The VM to create this VM on.
 * @kernel_va_start: Start of the region reserved for kernel objects.
 * @kernel_va_range: Size of the region reserved for kernel objects.
 *
 * Return: a positive VM ID on success, a negative error code otherwise.
 */
int panthor_vm_pool_create_vm(struct panthor_device *ptdev,
			      struct panthor_vm_pool *pool,
			      struct drm_panthor_vm_create *args)
{
	u64 kernel_va_start, kernel_va_range;
	struct panthor_vm *vm;
	int ret;
	u32 id;

	ret = panthor_vm_create_check_args(ptdev, args, &kernel_va_start, &kernel_va_range);
	if (ret)
		return ret;

	vm = panthor_vm_create(ptdev, false, kernel_va_start, kernel_va_range,
			       kernel_va_start, kernel_va_range);
	if (IS_ERR(vm))
		return PTR_ERR(vm);

	ret = xa_alloc(&pool->xa, &id, vm,
		       XA_LIMIT(1, PANTHOR_MAX_VMS_PER_FILE), GFP_KERNEL);

	if (ret) {
		panthor_vm_put(vm);
		return ret;
	}

	args->user_va_range = kernel_va_start;
	return id;
}

static void panthor_vm_destroy(struct panthor_vm *vm)
{
	if (!vm)
		return;

	vm->destroyed = true;

	mutex_lock(&vm->heaps.lock);
	panthor_heap_pool_destroy(vm->heaps.pool);
	vm->heaps.pool = NULL;
	mutex_unlock(&vm->heaps.lock);

	drm_WARN_ON(&vm->ptdev->base,
		    panthor_vm_unmap_range(vm, vm->base.mm_start, vm->base.mm_range));
	panthor_vm_put(vm);
}

/**
 * panthor_vm_pool_destroy_vm() - Destroy a VM.
 * @pool: VM pool.
 * @handle: VM handle.
 *
 * This function doesn't free the VM object or its resources, it just kills
 * all mappings, and makes sure nothing can be mapped after that point.
 *
 * If there was any active jobs at the time this function is called, these
 * jobs should experience page faults and be killed as a result.
 *
 * The VM resources are freed when the last reference on the VM object is
 * dropped.
 */
int panthor_vm_pool_destroy_vm(struct panthor_vm_pool *pool, u32 handle)
{
	struct panthor_vm *vm;

	vm = xa_erase(&pool->xa, handle);

	panthor_vm_destroy(vm);

	return vm ? 0 : -EINVAL;
}

/**
 * panthor_vm_pool_get_vm() - Retrieve VM object bound to a VM handle
 * @pool: VM pool to check.
 * @handle: Handle of the VM to retrieve.
 *
 * Return: A valid pointer if the VM exists, NULL otherwise.
 */
struct panthor_vm *
panthor_vm_pool_get_vm(struct panthor_vm_pool *pool, u32 handle)
{
	struct panthor_vm *vm;

	vm = panthor_vm_get(xa_load(&pool->xa, handle));

	return vm;
}

/**
 * panthor_vm_pool_destroy() - Destroy a VM pool.
 * @pfile: File.
 *
 * Destroy all VMs in the pool, and release the pool resources.
 *
 * Note that VMs can outlive the pool they were created from if other
 * objects hold a reference to there VMs.
 */
void panthor_vm_pool_destroy(struct panthor_file *pfile)
{
	struct panthor_vm *vm;
	unsigned long i;

	if (!pfile->vms)
		return;

	xa_for_each(&pfile->vms->xa, i, vm)
		panthor_vm_destroy(vm);

	xa_destroy(&pfile->vms->xa);
	kfree(pfile->vms);
}

/**
 * panthor_vm_pool_create() - Create a VM pool
 * @pfile: File.
 *
 * Return: 0 on success, a negative error code otherwise.
 */
int panthor_vm_pool_create(struct panthor_file *pfile)
{
	pfile->vms = kzalloc(sizeof(*pfile->vms), GFP_KERNEL);
	if (!pfile->vms)
		return -ENOMEM;

	xa_init_flags(&pfile->vms->xa, XA_FLAGS_ALLOC1);
	return 0;
}

/* dummy TLB ops, the real TLB flush happens in panthor_vm_flush_range() */
static void mmu_tlb_flush_all(void *cookie)
{
}

static void mmu_tlb_flush_walk(unsigned long iova, size_t size, size_t granule, void *cookie)
{
}

static const struct iommu_flush_ops mmu_tlb_ops = {
	.tlb_flush_all = mmu_tlb_flush_all,
	.tlb_flush_walk = mmu_tlb_flush_walk,
};

static const char *access_type_name(struct panthor_device *ptdev,
				    u32 fault_status)
{
	switch (fault_status & AS_FAULTSTATUS_ACCESS_TYPE_MASK) {
	case AS_FAULTSTATUS_ACCESS_TYPE_ATOMIC:
		return "ATOMIC";
	case AS_FAULTSTATUS_ACCESS_TYPE_READ:
		return "READ";
	case AS_FAULTSTATUS_ACCESS_TYPE_WRITE:
		return "WRITE";
	case AS_FAULTSTATUS_ACCESS_TYPE_EX:
		return "EXECUTE";
	default:
		drm_WARN_ON(&ptdev->base, 1);
		return NULL;
	}
}

static void panthor_mmu_irq_handler(struct panthor_device *ptdev, u32 status)
{
	bool has_unhandled_faults = false;

	status = panthor_mmu_fault_mask(ptdev, status);
	while (status) {
		u32 as = ffs(status | (status >> 16)) - 1;
		u32 mask = panthor_mmu_as_fault_mask(ptdev, as);
		u32 new_int_mask;
		u64 addr;
		u32 fault_status;
		u32 exception_type;
		u32 access_type;
		u32 source_id;

		fault_status = gpu_read(ptdev, AS_FAULTSTATUS(as));
		addr = gpu_read(ptdev, AS_FAULTADDRESS_LO(as));
		addr |= (u64)gpu_read(ptdev, AS_FAULTADDRESS_HI(as)) << 32;

		/* decode the fault status */
		exception_type = fault_status & 0xFF;
		access_type = (fault_status >> 8) & 0x3;
		source_id = (fault_status >> 16);

		mutex_lock(&ptdev->mmu->as.slots_lock);

		ptdev->mmu->as.faulty_mask |= mask;
		new_int_mask =
			panthor_mmu_fault_mask(ptdev, ~ptdev->mmu->as.faulty_mask);

		/* terminal fault, print info about the fault */
		drm_err(&ptdev->base,
			"Unhandled Page fault in AS%d at VA 0x%016llX\n"
			"raw fault status: 0x%X\n"
			"decoded fault status: %s\n"
			"exception type 0x%X: %s\n"
			"access type 0x%X: %s\n"
			"source id 0x%X\n",
			as, addr,
			fault_status,
			(fault_status & (1 << 10) ? "DECODER FAULT" : "SLAVE FAULT"),
			exception_type, panthor_exception_name(ptdev, exception_type),
			access_type, access_type_name(ptdev, fault_status),
			source_id);

		/* Ignore MMU interrupts on this AS until it's been
		 * re-enabled.
		 */
		ptdev->mmu->irq.mask = new_int_mask;
		gpu_write(ptdev, MMU_INT_MASK, new_int_mask);

		if (ptdev->mmu->as.slots[as].vm)
			ptdev->mmu->as.slots[as].vm->unhandled_fault = true;

		/* Disable the MMU to kill jobs on this AS. */
		panthor_mmu_as_disable(ptdev, as);
		mutex_unlock(&ptdev->mmu->as.slots_lock);

		status &= ~mask;
		has_unhandled_faults = true;
	}

	if (has_unhandled_faults)
		panthor_sched_report_mmu_fault(ptdev);
}
PANTHOR_IRQ_HANDLER(mmu, MMU, panthor_mmu_irq_handler);

/**
 * panthor_mmu_suspend() - Suspend the MMU logic
 * @ptdev: Device.
 *
 * All we do here is de-assign the AS slots on all active VMs, so things
 * get flushed to the main memory, and no further access to these VMs are
 * possible.
 *
 * We also suspend the MMU IRQ.
 */
void panthor_mmu_suspend(struct panthor_device *ptdev)
{
	mutex_lock(&ptdev->mmu->as.slots_lock);
	for (u32 i = 0; i < ARRAY_SIZE(ptdev->mmu->as.slots); i++) {
		struct panthor_vm *vm = ptdev->mmu->as.slots[i].vm;

		if (vm) {
			drm_WARN_ON(&ptdev->base, panthor_mmu_as_disable(ptdev, i));
			panthor_vm_release_as_locked(vm);
		}
	}
	mutex_unlock(&ptdev->mmu->as.slots_lock);

	panthor_mmu_irq_suspend(&ptdev->mmu->irq);
}

/**
 * panthor_mmu_resume() - Resume the MMU logic
 * @ptdev: Device.
 *
 * Resume the IRQ.
 *
 * We don't re-enable previously active VMs. We assume other parts of the
 * driver will call panthor_vm_active() on the VMs they intend to use.
 */
void panthor_mmu_resume(struct panthor_device *ptdev)
{
	mutex_lock(&ptdev->mmu->as.slots_lock);
	ptdev->mmu->as.alloc_mask = 0;
	ptdev->mmu->as.faulty_mask = 0;
	mutex_unlock(&ptdev->mmu->as.slots_lock);

	panthor_mmu_irq_resume(&ptdev->mmu->irq, panthor_mmu_fault_mask(ptdev, ~0));
}

/**
 * panthor_mmu_pre_reset() - Prepare for a reset
 * @ptdev: Device.
 *
 * Suspend the IRQ, and make sure all VM_BIND queues are stopped, so we
 * don't get asked to do a VM operation while the GPU is down.
 *
 * We don't cleanly shutdown the AS slots here, because the reset might
 * come from an AS_ACTIVE_BIT stuck situation.
 */
void panthor_mmu_pre_reset(struct panthor_device *ptdev)
{
	struct panthor_vm *vm;

	panthor_mmu_irq_suspend(&ptdev->mmu->irq);

	mutex_lock(&ptdev->mmu->vm.lock);
	ptdev->mmu->vm.reset_in_progress = true;
	list_for_each_entry(vm, &ptdev->mmu->vm.list, node)
		panthor_vm_stop(vm);
	mutex_unlock(&ptdev->mmu->vm.lock);
}

/**
 * panthor_mmu_post_reset() - Restore things after a reset
 * @ptdev: Device.
 *
 * Put the MMU logic back in action after a reset. That implies resuming the
 * IRQ and re-enabling the VM_BIND queues.
 */
void panthor_mmu_post_reset(struct panthor_device *ptdev)
{
	struct panthor_vm *vm;

	mutex_lock(&ptdev->mmu->as.slots_lock);

	/* Now that the reset is effective, we can assume that none of the
	 * AS slots are setup, and clear the faulty flags too.
	 */
	ptdev->mmu->as.alloc_mask = 0;
	ptdev->mmu->as.faulty_mask = 0;

	for (u32 i = 0; i < ARRAY_SIZE(ptdev->mmu->as.slots); i++) {
		struct panthor_vm *vm = ptdev->mmu->as.slots[i].vm;

		if (vm)
			panthor_vm_release_as_locked(vm);
	}

	mutex_unlock(&ptdev->mmu->as.slots_lock);

	panthor_mmu_irq_resume(&ptdev->mmu->irq, panthor_mmu_fault_mask(ptdev, ~0));

	/* Restart the VM_BIND queues. */
	mutex_lock(&ptdev->mmu->vm.lock);
	list_for_each_entry(vm, &ptdev->mmu->vm.list, node) {
		panthor_vm_start(vm);
	}
	ptdev->mmu->vm.reset_in_progress = false;
	mutex_unlock(&ptdev->mmu->vm.lock);
}

static void panthor_vm_free(struct drm_gpuvm *gpuvm)
{
	struct panthor_vm *vm = container_of(gpuvm, struct panthor_vm, base);
	struct panthor_device *ptdev = vm->ptdev;

	mutex_lock(&vm->heaps.lock);
	if (drm_WARN_ON(&ptdev->base, vm->heaps.pool))
		panthor_heap_pool_destroy(vm->heaps.pool);
	mutex_unlock(&vm->heaps.lock);
	mutex_destroy(&vm->heaps.lock);

	mutex_lock(&ptdev->mmu->vm.lock);
	list_del(&vm->node);
	/* Restore the scheduler state so we can call drm_sched_entity_destroy()
	 * and drm_sched_fini(). If get there, that means we have no job left
	 * and no new jobs can be queued, so we can start the scheduler without
	 * risking interfering with the reset.
	 */
	if (ptdev->mmu->vm.reset_in_progress)
		panthor_vm_start(vm);
	mutex_unlock(&ptdev->mmu->vm.lock);

	drm_sched_entity_destroy(&vm->entity);
	drm_sched_fini(&vm->sched);

	mutex_lock(&ptdev->mmu->as.slots_lock);
	if (vm->as.id >= 0) {
		int cookie;

		if (drm_dev_enter(&ptdev->base, &cookie)) {
			panthor_mmu_as_disable(ptdev, vm->as.id);
			drm_dev_exit(cookie);
		}

		ptdev->mmu->as.slots[vm->as.id].vm = NULL;
		clear_bit(vm->as.id, &ptdev->mmu->as.alloc_mask);
		list_del(&vm->as.lru_node);
	}
	mutex_unlock(&ptdev->mmu->as.slots_lock);

	free_io_pgtable_ops(vm->pgtbl_ops);

	drm_mm_takedown(&vm->mm);
	kfree(vm);
}

/**
 * panthor_vm_put() - Release a reference on a VM
 * @vm: VM to release the reference on. Can be NULL.
 */
void panthor_vm_put(struct panthor_vm *vm)
{
	drm_gpuvm_put(vm ? &vm->base : NULL);
}

/**
 * panthor_vm_get() - Get a VM reference
 * @vm: VM to get the reference on. Can be NULL.
 *
 * Return: @vm value.
 */
struct panthor_vm *panthor_vm_get(struct panthor_vm *vm)
{
	if (vm)
		drm_gpuvm_get(&vm->base);

	return vm;
}

/**
 * panthor_vm_get_heap_pool() - Get the heap pool attached to a VM
 * @vm: VM to query the heap pool on.
 * @create: True if the heap pool should be created when it doesn't exist.
 *
 * Heap pools are per-VM. This function allows one to retrieve the heap pool
 * attached to a VM.
 *
 * If no heap pool exists yet, and @create is true, we create one.
 *
 * The returned panthor_heap_pool should be released with panthor_heap_pool_put().
 *
 * Return: A valid pointer on success, an ERR_PTR() otherwise.
 */
struct panthor_heap_pool *panthor_vm_get_heap_pool(struct panthor_vm *vm, bool create)
{
	struct panthor_heap_pool *pool;

	mutex_lock(&vm->heaps.lock);
	if (!vm->heaps.pool && create) {
		if (vm->destroyed)
			pool = ERR_PTR(-EINVAL);
		else
			pool = panthor_heap_pool_create(vm->ptdev, vm);

		if (!IS_ERR(pool))
			vm->heaps.pool = panthor_heap_pool_get(pool);
	} else {
		pool = panthor_heap_pool_get(vm->heaps.pool);
		if (!pool)
			pool = ERR_PTR(-ENOENT);
	}
	mutex_unlock(&vm->heaps.lock);

	return pool;
}

static u64 mair_to_memattr(u64 mair)
{
	u64 memattr = 0;
	u32 i;

	for (i = 0; i < 8; i++) {
		u8 in_attr = mair >> (8 * i), out_attr;
		u8 outer = in_attr >> 4, inner = in_attr & 0xf;

		/* For caching to be enabled, inner and outer caching policy
		 * have to be both write-back, if one of them is write-through
		 * or non-cacheable, we just choose non-cacheable. Device
		 * memory is also translated to non-cacheable.
		 */
		if (!(outer & 3) || !(outer & 4) || !(inner & 4)) {
			out_attr = AS_MEMATTR_AARCH64_INNER_OUTER_NC |
				   AS_MEMATTR_AARCH64_SH_MIDGARD_INNER |
				   AS_MEMATTR_AARCH64_INNER_ALLOC_EXPL(false, false);
		} else {
			/* Use SH_CPU_INNER mode so SH_IS, which is used when
			 * IOMMU_CACHE is set, actually maps to the standard
			 * definition of inner-shareable and not Mali's
			 * internal-shareable mode.
			 */
			out_attr = AS_MEMATTR_AARCH64_INNER_OUTER_WB |
				   AS_MEMATTR_AARCH64_SH_CPU_INNER |
				   AS_MEMATTR_AARCH64_INNER_ALLOC_EXPL(inner & 1, inner & 2);
		}

		memattr |= (u64)out_attr << (8 * i);
	}

	return memattr;
}

static void panthor_vma_link(struct panthor_vm *vm,
			     struct panthor_vma *vma,
			     struct drm_gpuvm_bo *vm_bo)
{
	struct panthor_gem_object *bo = to_panthor_bo(vma->base.gem.obj);

	mutex_lock(&bo->gpuva_list_lock);
	drm_gpuva_link(&vma->base, vm_bo);
	drm_WARN_ON(&vm->ptdev->base, drm_gpuvm_bo_put(vm_bo));
	mutex_unlock(&bo->gpuva_list_lock);
}

static void panthor_vma_unlink(struct panthor_vm *vm,
			       struct panthor_vma *vma)
{
	struct panthor_gem_object *bo = to_panthor_bo(vma->base.gem.obj);
	struct drm_gpuvm_bo *vm_bo = drm_gpuvm_bo_get(vma->base.vm_bo);

	mutex_lock(&bo->gpuva_list_lock);
	drm_gpuva_unlink(&vma->base);
	mutex_unlock(&bo->gpuva_list_lock);

	/* drm_gpuva_unlink() release the vm_bo, but we manually retained it
	 * when entering this function, so we can implement deferred VMA
	 * destruction. Re-assign it here.
	 */
	vma->base.vm_bo = vm_bo;
	list_add_tail(&vma->node, &vm->op_ctx->returned_vmas);
}

static void panthor_vma_init(struct panthor_vma *vma, u32 flags)
{
	INIT_LIST_HEAD(&vma->node);
	vma->flags = flags;
}

#define PANTHOR_VM_MAP_FLAGS \
	(DRM_PANTHOR_VM_BIND_OP_MAP_READONLY | \
	 DRM_PANTHOR_VM_BIND_OP_MAP_NOEXEC | \
	 DRM_PANTHOR_VM_BIND_OP_MAP_UNCACHED)

static int panthor_gpuva_sm_step_map(struct drm_gpuva_op *op, void *priv)
{
	struct panthor_vm *vm = priv;
	struct panthor_vm_op_ctx *op_ctx = vm->op_ctx;
	struct panthor_vma *vma = panthor_vm_op_ctx_get_vma(op_ctx);
	int ret;

	if (!vma)
		return -EINVAL;

	panthor_vma_init(vma, op_ctx->flags & PANTHOR_VM_MAP_FLAGS);

	ret = panthor_vm_map_pages(vm, op->map.va.addr, flags_to_prot(vma->flags),
				   op_ctx->map.sgt, op->map.gem.offset,
				   op->map.va.range);
	if (ret)
		return ret;

	/* Ref owned by the mapping now, clear the obj field so we don't release the
	 * pinning/obj ref behind GPUVA's back.
	 */
	drm_gpuva_map(&vm->base, &vma->base, &op->map);
	panthor_vma_link(vm, vma, op_ctx->map.vm_bo);
	op_ctx->map.vm_bo = NULL;
	return 0;
}

static int panthor_gpuva_sm_step_remap(struct drm_gpuva_op *op,
				       void *priv)
{
	struct panthor_vma *unmap_vma = container_of(op->remap.unmap->va, struct panthor_vma, base);
	struct panthor_vm *vm = priv;
	struct panthor_vm_op_ctx *op_ctx = vm->op_ctx;
	struct panthor_vma *prev_vma = NULL, *next_vma = NULL;
	u64 unmap_start, unmap_range;
	int ret;

	drm_gpuva_op_remap_to_unmap_range(&op->remap, &unmap_start, &unmap_range);
	ret = panthor_vm_unmap_pages(vm, unmap_start, unmap_range);
	if (ret)
		return ret;

	if (op->remap.prev) {
		prev_vma = panthor_vm_op_ctx_get_vma(op_ctx);
		panthor_vma_init(prev_vma, unmap_vma->flags);
	}

	if (op->remap.next) {
		next_vma = panthor_vm_op_ctx_get_vma(op_ctx);
		panthor_vma_init(next_vma, unmap_vma->flags);
	}

	drm_gpuva_remap(prev_vma ? &prev_vma->base : NULL,
			next_vma ? &next_vma->base : NULL,
			&op->remap);

	if (prev_vma) {
		/* panthor_vma_link() transfers the vm_bo ownership to
		 * the VMA object. Since the vm_bo we're passing is still
		 * owned by the old mapping which will be released when this
		 * mapping is destroyed, we need to grab a ref here.
		 */
		panthor_vma_link(vm, prev_vma,
				 drm_gpuvm_bo_get(op->remap.unmap->va->vm_bo));
	}

	if (next_vma) {
		panthor_vma_link(vm, next_vma,
				 drm_gpuvm_bo_get(op->remap.unmap->va->vm_bo));
	}

	panthor_vma_unlink(vm, unmap_vma);
	return 0;
}

static int panthor_gpuva_sm_step_unmap(struct drm_gpuva_op *op,
				       void *priv)
{
	struct panthor_vma *unmap_vma = container_of(op->unmap.va, struct panthor_vma, base);
	struct panthor_vm *vm = priv;
	int ret;

	ret = panthor_vm_unmap_pages(vm, unmap_vma->base.va.addr,
				     unmap_vma->base.va.range);
	if (drm_WARN_ON(&vm->ptdev->base, ret))
		return ret;

	drm_gpuva_unmap(&op->unmap);
	panthor_vma_unlink(vm, unmap_vma);
	return 0;
}

static const struct drm_gpuvm_ops panthor_gpuvm_ops = {
	.vm_free = panthor_vm_free,
	.sm_step_map = panthor_gpuva_sm_step_map,
	.sm_step_remap = panthor_gpuva_sm_step_remap,
	.sm_step_unmap = panthor_gpuva_sm_step_unmap,
};

/**
 * panthor_vm_resv() - Get the dma_resv object attached to a VM.
 * @vm: VM to get the dma_resv of.
 *
 * Return: A dma_resv object.
 */
struct dma_resv *panthor_vm_resv(struct panthor_vm *vm)
{
	return drm_gpuvm_resv(&vm->base);
}

struct drm_gem_object *panthor_vm_root_gem(struct panthor_vm *vm)
{
	if (!vm)
		return NULL;

	return vm->base.r_obj;
}

static int
panthor_vm_exec_op(struct panthor_vm *vm, struct panthor_vm_op_ctx *op,
		   bool flag_vm_unusable_on_failure)
{
	u32 op_type = op->flags & DRM_PANTHOR_VM_BIND_OP_TYPE_MASK;
	int ret;

	if (op_type == DRM_PANTHOR_VM_BIND_OP_TYPE_SYNC_ONLY)
		return 0;

	mutex_lock(&vm->op_lock);
	vm->op_ctx = op;
	switch (op_type) {
	case DRM_PANTHOR_VM_BIND_OP_TYPE_MAP:
		if (vm->unusable) {
			ret = -EINVAL;
			break;
		}

		ret = drm_gpuvm_sm_map(&vm->base, vm, op->va.addr, op->va.range,
				       op->map.vm_bo->obj, op->map.bo_offset);
		break;

	case DRM_PANTHOR_VM_BIND_OP_TYPE_UNMAP:
		ret = drm_gpuvm_sm_unmap(&vm->base, vm, op->va.addr, op->va.range);
		break;

	default:
		ret = -EINVAL;
		break;
	}

	if (ret && flag_vm_unusable_on_failure)
		vm->unusable = true;

	vm->op_ctx = NULL;
	mutex_unlock(&vm->op_lock);

	return ret;
}

static struct dma_fence *
panthor_vm_bind_run_job(struct drm_sched_job *sched_job)
{
	struct panthor_vm_bind_job *job = container_of(sched_job, struct panthor_vm_bind_job, base);
	bool cookie;
	int ret;

	/* Not only we report an error whose result is propagated to the
	 * drm_sched finished fence, but we also flag the VM as unusable, because
	 * a failure in the async VM_BIND results in an inconsistent state. VM needs
	 * to be destroyed and recreated.
	 */
	cookie = dma_fence_begin_signalling();
	ret = panthor_vm_exec_op(job->vm, &job->ctx, true);
	dma_fence_end_signalling(cookie);

	return ret ? ERR_PTR(ret) : NULL;
}

static void panthor_vm_bind_job_release(struct kref *kref)
{
	struct panthor_vm_bind_job *job = container_of(kref, struct panthor_vm_bind_job, refcount);

	if (job->base.s_fence)
		drm_sched_job_cleanup(&job->base);

	panthor_vm_cleanup_op_ctx(&job->ctx, job->vm);
	panthor_vm_put(job->vm);
	kfree(job);
}

/**
 * panthor_vm_bind_job_put() - Release a VM_BIND job reference
 * @sched_job: Job to release the reference on.
 */
void panthor_vm_bind_job_put(struct drm_sched_job *sched_job)
{
	struct panthor_vm_bind_job *job =
		container_of(sched_job, struct panthor_vm_bind_job, base);

	if (sched_job)
		kref_put(&job->refcount, panthor_vm_bind_job_release);
}

static void
panthor_vm_bind_free_job(struct drm_sched_job *sched_job)
{
	struct panthor_vm_bind_job *job =
		container_of(sched_job, struct panthor_vm_bind_job, base);

	drm_sched_job_cleanup(sched_job);

	/* Do the heavy cleanups asynchronously, so we're out of the
	 * dma-signaling path and can acquire dma-resv locks safely.
	 */
	queue_work(panthor_cleanup_wq, &job->cleanup_op_ctx_work);
}

static enum drm_gpu_sched_stat
panthor_vm_bind_timedout_job(struct drm_sched_job *sched_job)
{
	WARN(1, "VM_BIND ops are synchronous for now, there should be no timeout!");
	return DRM_GPU_SCHED_STAT_NOMINAL;
}

static const struct drm_sched_backend_ops panthor_vm_bind_ops = {
	.run_job = panthor_vm_bind_run_job,
	.free_job = panthor_vm_bind_free_job,
	.timedout_job = panthor_vm_bind_timedout_job,
};

/**
 * panthor_vm_create() - Create a VM
 * @ptdev: Device.
 * @for_mcu: True if this is the FW MCU VM.
 * @kernel_va_start: Start of the range reserved for kernel BO mapping.
 * @kernel_va_size: Size of the range reserved for kernel BO mapping.
 * @auto_kernel_va_start: Start of the auto-VA kernel range.
 * @auto_kernel_va_size: Size of the auto-VA kernel range.
 *
 * Return: A valid pointer on success, an ERR_PTR() otherwise.
 */
struct panthor_vm *
panthor_vm_create(struct panthor_device *ptdev, bool for_mcu,
		  u64 kernel_va_start, u64 kernel_va_size,
		  u64 auto_kernel_va_start, u64 auto_kernel_va_size)
{
	u32 va_bits = GPU_MMU_FEATURES_VA_BITS(ptdev->gpu_info.mmu_features);
	u32 pa_bits = GPU_MMU_FEATURES_PA_BITS(ptdev->gpu_info.mmu_features);
	u64 full_va_range = 1ull << va_bits;
	struct drm_gem_object *dummy_gem;
	struct drm_gpu_scheduler *sched;
	struct io_pgtable_cfg pgtbl_cfg;
	u64 mair, min_va, va_range;
	struct panthor_vm *vm;
	int ret;

	vm = kzalloc(sizeof(*vm), GFP_KERNEL);
	if (!vm)
		return ERR_PTR(-ENOMEM);

	/* We allocate a dummy GEM for the VM. */
	dummy_gem = drm_gpuvm_resv_object_alloc(&ptdev->base);
	if (!dummy_gem) {
		ret = -ENOMEM;
		goto err_free_vm;
	}

	mutex_init(&vm->heaps.lock);
	vm->for_mcu = for_mcu;
	vm->ptdev = ptdev;
	mutex_init(&vm->op_lock);

	if (for_mcu) {
		/* CSF MCU is a cortex M7, and can only address 4G */
		min_va = 0;
		va_range = SZ_4G;
	} else {
		min_va = 0;
		va_range = full_va_range;
	}

	mutex_init(&vm->mm_lock);
	drm_mm_init(&vm->mm, kernel_va_start, kernel_va_size);
	vm->kernel_auto_va.start = auto_kernel_va_start;
	vm->kernel_auto_va.end = vm->kernel_auto_va.start + auto_kernel_va_size - 1;

	INIT_LIST_HEAD(&vm->node);
	INIT_LIST_HEAD(&vm->as.lru_node);
	vm->as.id = -1;
	refcount_set(&vm->as.active_cnt, 0);

	pgtbl_cfg = (struct io_pgtable_cfg) {
		.pgsize_bitmap	= SZ_4K | SZ_2M,
		.ias		= va_bits,
		.oas		= pa_bits,
		.coherent_walk	= ptdev->coherent,
		.tlb		= &mmu_tlb_ops,
		.iommu_dev	= ptdev->base.dev,
		.alloc		= alloc_pt,
		.free		= free_pt,
	};

	vm->pgtbl_ops = alloc_io_pgtable_ops(ARM_64_LPAE_S1, &pgtbl_cfg, vm);
	if (!vm->pgtbl_ops) {
		ret = -EINVAL;
		goto err_mm_takedown;
	}

	/* Bind operations are synchronous for now, no timeout needed. */
	ret = drm_sched_init(&vm->sched, &panthor_vm_bind_ops, ptdev->mmu->vm.wq,
			     1, 1, 0,
			     MAX_SCHEDULE_TIMEOUT, NULL, NULL,
			     "panthor-vm-bind", ptdev->base.dev);
	if (ret)
		goto err_free_io_pgtable;

	sched = &vm->sched;
	ret = drm_sched_entity_init(&vm->entity, 0, &sched, 1, NULL);
	if (ret)
		goto err_sched_fini;

	mair = io_pgtable_ops_to_pgtable(vm->pgtbl_ops)->cfg.arm_lpae_s1_cfg.mair;
	vm->memattr = mair_to_memattr(mair);

	mutex_lock(&ptdev->mmu->vm.lock);
	list_add_tail(&vm->node, &ptdev->mmu->vm.list);

	/* If a reset is in progress, stop the scheduler. */
	if (ptdev->mmu->vm.reset_in_progress)
		panthor_vm_stop(vm);
	mutex_unlock(&ptdev->mmu->vm.lock);

	/* We intentionally leave the reserved range to zero, because we want kernel VMAs
	 * to be handled the same way user VMAs are.
	 */
	drm_gpuvm_init(&vm->base, for_mcu ? "panthor-MCU-VM" : "panthor-GPU-VM",
		       DRM_GPUVM_RESV_PROTECTED, &ptdev->base, dummy_gem,
		       min_va, va_range, 0, 0, &panthor_gpuvm_ops);
	drm_gem_object_put(dummy_gem);
	return vm;

err_sched_fini:
	drm_sched_fini(&vm->sched);

err_free_io_pgtable:
	free_io_pgtable_ops(vm->pgtbl_ops);

err_mm_takedown:
	drm_mm_takedown(&vm->mm);
	drm_gem_object_put(dummy_gem);

err_free_vm:
	kfree(vm);
	return ERR_PTR(ret);
}

static int
panthor_vm_bind_prepare_op_ctx(struct drm_file *file,
			       struct panthor_vm *vm,
			       const struct drm_panthor_vm_bind_op *op,
			       struct panthor_vm_op_ctx *op_ctx)
{
	struct drm_gem_object *gem;
	int ret;

	/* Aligned on page size. */
	if ((op->va | op->size) & ~PAGE_MASK)
		return -EINVAL;

	switch (op->flags & DRM_PANTHOR_VM_BIND_OP_TYPE_MASK) {
	case DRM_PANTHOR_VM_BIND_OP_TYPE_MAP:
		gem = drm_gem_object_lookup(file, op->bo_handle);
		ret = panthor_vm_prepare_map_op_ctx(op_ctx, vm,
						    gem ? to_panthor_bo(gem) : NULL,
						    op->bo_offset,
						    op->size,
						    op->va,
						    op->flags);
		drm_gem_object_put(gem);
		return ret;

	case DRM_PANTHOR_VM_BIND_OP_TYPE_UNMAP:
		if (op->flags & ~DRM_PANTHOR_VM_BIND_OP_TYPE_MASK)
			return -EINVAL;

		if (op->bo_handle || op->bo_offset)
			return -EINVAL;

		return panthor_vm_prepare_unmap_op_ctx(op_ctx, vm, op->va, op->size);

	case DRM_PANTHOR_VM_BIND_OP_TYPE_SYNC_ONLY:
		if (op->flags & ~DRM_PANTHOR_VM_BIND_OP_TYPE_MASK)
			return -EINVAL;

		if (op->bo_handle || op->bo_offset)
			return -EINVAL;

		if (op->va || op->size)
			return -EINVAL;

		if (!op->syncs.count)
			return -EINVAL;

		panthor_vm_prepare_sync_only_op_ctx(op_ctx, vm);
		return 0;

	default:
		return -EINVAL;
	}
}

static void panthor_vm_bind_job_cleanup_op_ctx_work(struct work_struct *work)
{
	struct panthor_vm_bind_job *job =
		container_of(work, struct panthor_vm_bind_job, cleanup_op_ctx_work);

	panthor_vm_bind_job_put(&job->base);
}

/**
 * panthor_vm_bind_job_create() - Create a VM_BIND job
 * @file: File.
 * @vm: VM targeted by the VM_BIND job.
 * @op: VM operation data.
 *
 * Return: A valid pointer on success, an ERR_PTR() otherwise.
 */
struct drm_sched_job *
panthor_vm_bind_job_create(struct drm_file *file,
			   struct panthor_vm *vm,
			   const struct drm_panthor_vm_bind_op *op)
{
	struct panthor_vm_bind_job *job;
	int ret;

	if (!vm)
		return ERR_PTR(-EINVAL);

	if (vm->destroyed || vm->unusable)
		return ERR_PTR(-EINVAL);

	job = kzalloc(sizeof(*job), GFP_KERNEL);
	if (!job)
		return ERR_PTR(-ENOMEM);

	ret = panthor_vm_bind_prepare_op_ctx(file, vm, op, &job->ctx);
	if (ret) {
		kfree(job);
		return ERR_PTR(ret);
	}

	INIT_WORK(&job->cleanup_op_ctx_work, panthor_vm_bind_job_cleanup_op_ctx_work);
	kref_init(&job->refcount);
	job->vm = panthor_vm_get(vm);

	ret = drm_sched_job_init(&job->base, &vm->entity, 1, vm);
	if (ret)
		goto err_put_job;

	return &job->base;

err_put_job:
	panthor_vm_bind_job_put(&job->base);
	return ERR_PTR(ret);
}

/**
 * panthor_vm_bind_job_prepare_resvs() - Prepare VM_BIND job dma_resvs
 * @exec: The locking/preparation context.
 * @sched_job: The job to prepare resvs on.
 *
 * Locks and prepare the VM resv.
 *
 * If this is a map operation, locks and prepares the GEM resv.
 *
 * Return: 0 on success, a negative error code otherwise.
 */
int panthor_vm_bind_job_prepare_resvs(struct drm_exec *exec,
				      struct drm_sched_job *sched_job)
{
	struct panthor_vm_bind_job *job = container_of(sched_job, struct panthor_vm_bind_job, base);
	int ret;

	/* Acquire the VM lock an reserve a slot for this VM bind job. */
	ret = drm_gpuvm_prepare_vm(&job->vm->base, exec, 1);
	if (ret)
		return ret;

	if (job->ctx.map.vm_bo) {
		/* Lock/prepare the GEM being mapped. */
		ret = drm_exec_prepare_obj(exec, job->ctx.map.vm_bo->obj, 1);
		if (ret)
			return ret;
	}

	return 0;
}

/**
 * panthor_vm_bind_job_update_resvs() - Update the resv objects touched by a job
 * @exec: drm_exec context.
 * @sched_job: Job to update the resvs on.
 */
void panthor_vm_bind_job_update_resvs(struct drm_exec *exec,
				      struct drm_sched_job *sched_job)
{
	struct panthor_vm_bind_job *job = container_of(sched_job, struct panthor_vm_bind_job, base);

	/* Explicit sync => we just register our job finished fence as bookkeep. */
	drm_gpuvm_resv_add_fence(&job->vm->base, exec,
				 &sched_job->s_fence->finished,
				 DMA_RESV_USAGE_BOOKKEEP,
				 DMA_RESV_USAGE_BOOKKEEP);
}

void panthor_vm_update_resvs(struct panthor_vm *vm, struct drm_exec *exec,
			     struct dma_fence *fence,
			     enum dma_resv_usage private_usage,
			     enum dma_resv_usage extobj_usage)
{
	drm_gpuvm_resv_add_fence(&vm->base, exec, fence, private_usage, extobj_usage);
}

/**
 * panthor_vm_bind_exec_sync_op() - Execute a VM_BIND operation synchronously.
 * @file: File.
 * @vm: VM targeted by the VM operation.
 * @op: Data describing the VM operation.
 *
 * Return: 0 on success, a negative error code otherwise.
 */
int panthor_vm_bind_exec_sync_op(struct drm_file *file,
				 struct panthor_vm *vm,
				 struct drm_panthor_vm_bind_op *op)
{
	struct panthor_vm_op_ctx op_ctx;
	int ret;

	/* No sync objects allowed on synchronous operations. */
	if (op->syncs.count)
		return -EINVAL;

	if (!op->size)
		return 0;

	ret = panthor_vm_bind_prepare_op_ctx(file, vm, op, &op_ctx);
	if (ret)
		return ret;

	ret = panthor_vm_exec_op(vm, &op_ctx, false);
	panthor_vm_cleanup_op_ctx(&op_ctx, vm);

	return ret;
}

/**
 * panthor_vm_map_bo_range() - Map a GEM object range to a VM
 * @vm: VM to map the GEM to.
 * @bo: GEM object to map.
 * @offset: Offset in the GEM object.
 * @size: Size to map.
 * @va: Virtual address to map the object to.
 * @flags: Combination of drm_panthor_vm_bind_op_flags flags.
 * Only map-related flags are valid.
 *
 * Internal use only. For userspace requests, use
 * panthor_vm_bind_exec_sync_op() instead.
 *
 * Return: 0 on success, a negative error code otherwise.
 */
int panthor_vm_map_bo_range(struct panthor_vm *vm, struct panthor_gem_object *bo,
			    u64 offset, u64 size, u64 va, u32 flags)
{
	struct panthor_vm_op_ctx op_ctx;
	int ret;

	ret = panthor_vm_prepare_map_op_ctx(&op_ctx, vm, bo, offset, size, va, flags);
	if (ret)
		return ret;

	ret = panthor_vm_exec_op(vm, &op_ctx, false);
	panthor_vm_cleanup_op_ctx(&op_ctx, vm);

	return ret;
}

/**
 * panthor_vm_unmap_range() - Unmap a portion of the VA space
 * @vm: VM to unmap the region from.
 * @va: Virtual address to unmap. Must be 4k aligned.
 * @size: Size of the region to unmap. Must be 4k aligned.
 *
 * Internal use only. For userspace requests, use
 * panthor_vm_bind_exec_sync_op() instead.
 *
 * Return: 0 on success, a negative error code otherwise.
 */
int panthor_vm_unmap_range(struct panthor_vm *vm, u64 va, u64 size)
{
	struct panthor_vm_op_ctx op_ctx;
	int ret;

	ret = panthor_vm_prepare_unmap_op_ctx(&op_ctx, vm, va, size);
	if (ret)
		return ret;

	ret = panthor_vm_exec_op(vm, &op_ctx, false);
	panthor_vm_cleanup_op_ctx(&op_ctx, vm);

	return ret;
}

/**
 * panthor_vm_prepare_mapped_bos_resvs() - Prepare resvs on VM BOs.
 * @exec: Locking/preparation context.
 * @vm: VM targeted by the GPU job.
 * @slot_count: Number of slots to reserve.
 *
 * GPU jobs assume all BOs bound to the VM at the time the job is submitted
 * are available when the job is executed. In order to guarantee that, we
 * need to reserve a slot on all BOs mapped to a VM and update this slot with
 * the job fence after its submission.
 *
 * Return: 0 on success, a negative error code otherwise.
 */
int panthor_vm_prepare_mapped_bos_resvs(struct drm_exec *exec, struct panthor_vm *vm,
					u32 slot_count)
{
	int ret;

	/* Acquire the VM lock and reserve a slot for this GPU job. */
	ret = drm_gpuvm_prepare_vm(&vm->base, exec, slot_count);
	if (ret)
		return ret;

	return drm_gpuvm_prepare_objects(&vm->base, exec, slot_count);
}

/**
 * panthor_mmu_unplug() - Unplug the MMU logic
 * @ptdev: Device.
 *
 * No access to the MMU regs should be done after this function is called.
 * We suspend the IRQ and disable all VMs to guarantee that.
 */
void panthor_mmu_unplug(struct panthor_device *ptdev)
{
	panthor_mmu_irq_suspend(&ptdev->mmu->irq);

	mutex_lock(&ptdev->mmu->as.slots_lock);
	for (u32 i = 0; i < ARRAY_SIZE(ptdev->mmu->as.slots); i++) {
		struct panthor_vm *vm = ptdev->mmu->as.slots[i].vm;

		if (vm) {
			drm_WARN_ON(&ptdev->base, panthor_mmu_as_disable(ptdev, i));
			panthor_vm_release_as_locked(vm);
		}
	}
	mutex_unlock(&ptdev->mmu->as.slots_lock);
}

static void panthor_mmu_release_wq(struct drm_device *ddev, void *res)
{
	destroy_workqueue(res);
}

/**
 * panthor_mmu_init() - Initialize the MMU logic.
 * @ptdev: Device.
 *
 * Return: 0 on success, a negative error code otherwise.
 */
int panthor_mmu_init(struct panthor_device *ptdev)
{
	u32 va_bits = GPU_MMU_FEATURES_VA_BITS(ptdev->gpu_info.mmu_features);
	struct panthor_mmu *mmu;
	int ret, irq;

	mmu = drmm_kzalloc(&ptdev->base, sizeof(*mmu), GFP_KERNEL);
	if (!mmu)
		return -ENOMEM;

	INIT_LIST_HEAD(&mmu->as.lru_list);

	ret = drmm_mutex_init(&ptdev->base, &mmu->as.slots_lock);
	if (ret)
		return ret;

	INIT_LIST_HEAD(&mmu->vm.list);
	ret = drmm_mutex_init(&ptdev->base, &mmu->vm.lock);
	if (ret)
		return ret;

	ptdev->mmu = mmu;

	irq = platform_get_irq_byname(to_platform_device(ptdev->base.dev), "mmu");
	if (irq <= 0)
		return -ENODEV;

	ret = panthor_request_mmu_irq(ptdev, &mmu->irq, irq,
				      panthor_mmu_fault_mask(ptdev, ~0));
	if (ret)
		return ret;

	mmu->vm.wq = alloc_workqueue("panthor-vm-bind", WQ_UNBOUND, 0);
	if (!mmu->vm.wq)
		return -ENOMEM;

	/* On 32-bit kernels, the VA space is limited by the io_pgtable_ops abstraction,
	 * which passes iova as an unsigned long. Patch the mmu_features to reflect this
	 * limitation.
	 */
	if (sizeof(unsigned long) * 8 < va_bits) {
		ptdev->gpu_info.mmu_features &= ~GENMASK(7, 0);
		ptdev->gpu_info.mmu_features |= sizeof(unsigned long) * 8;
	}

	return drmm_add_action_or_reset(&ptdev->base, panthor_mmu_release_wq, mmu->vm.wq);
}

#ifdef CONFIG_DEBUG_FS
static int show_vm_gpuvas(struct panthor_vm *vm, struct seq_file *m)
{
	int ret;

	mutex_lock(&vm->op_lock);
	ret = drm_debugfs_gpuva_info(m, &vm->base);
	mutex_unlock(&vm->op_lock);

	return ret;
}

static int show_each_vm(struct seq_file *m, void *arg)
{
	struct drm_info_node *node = (struct drm_info_node *)m->private;
	struct drm_device *ddev = node->minor->dev;
	struct panthor_device *ptdev = container_of(ddev, struct panthor_device, base);
	int (*show)(struct panthor_vm *, struct seq_file *) = node->info_ent->data;
	struct panthor_vm *vm;
	int ret = 0;

	mutex_lock(&ptdev->mmu->vm.lock);
	list_for_each_entry(vm, &ptdev->mmu->vm.list, node) {
		ret = show(vm, m);
		if (ret < 0)
			break;

		seq_puts(m, "\n");
	}
	mutex_unlock(&ptdev->mmu->vm.lock);

	return ret;
}

static struct drm_info_list panthor_mmu_debugfs_list[] = {
	DRM_DEBUGFS_GPUVA_INFO(show_each_vm, show_vm_gpuvas),
};

/**
 * panthor_mmu_debugfs_init() - Initialize MMU debugfs entries
 * @minor: Minor.
 */
void panthor_mmu_debugfs_init(struct drm_minor *minor)
{
	drm_debugfs_create_files(panthor_mmu_debugfs_list,
				 ARRAY_SIZE(panthor_mmu_debugfs_list),
				 minor->debugfs_root, minor);
}
#endif /* CONFIG_DEBUG_FS */

/**
 * panthor_mmu_pt_cache_init() - Initialize the page table cache.
 *
 * Return: 0 on success, a negative error code otherwise.
 */
int panthor_mmu_pt_cache_init(void)
{
	pt_cache = kmem_cache_create("panthor-mmu-pt", SZ_4K, SZ_4K, 0, NULL);
	if (!pt_cache)
		return -ENOMEM;

	return 0;
}

/**
 * panthor_mmu_pt_cache_fini() - Destroy the page table cache.
 */
void panthor_mmu_pt_cache_fini(void)
{
	kmem_cache_destroy(pt_cache);
}