summaryrefslogtreecommitdiffstats
path: root/drivers/base/core.c
blob: 139cdf7e73271a02182cf4f7cdba707ded7cce55 (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
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
// SPDX-License-Identifier: GPL-2.0
/*
 * drivers/base/core.c - core driver model code (device registration, etc)
 *
 * Copyright (c) 2002-3 Patrick Mochel
 * Copyright (c) 2002-3 Open Source Development Labs
 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
 * Copyright (c) 2006 Novell, Inc.
 */

#include <linux/acpi.h>
#include <linux/cpufreq.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/fwnode.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/kdev_t.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/genhd.h>
#include <linux/mutex.h>
#include <linux/pm_runtime.h>
#include <linux/netdevice.h>
#include <linux/sched/signal.h>
#include <linux/sysfs.h>

#include "base.h"
#include "power/power.h"

#ifdef CONFIG_SYSFS_DEPRECATED
#ifdef CONFIG_SYSFS_DEPRECATED_V2
long sysfs_deprecated = 1;
#else
long sysfs_deprecated = 0;
#endif
static int __init sysfs_deprecated_setup(char *arg)
{
	return kstrtol(arg, 10, &sysfs_deprecated);
}
early_param("sysfs.deprecated", sysfs_deprecated_setup);
#endif

/* Device links support. */
static LIST_HEAD(wait_for_suppliers);
static DEFINE_MUTEX(wfs_lock);
static LIST_HEAD(deferred_sync);
static unsigned int defer_sync_state_count = 1;

#ifdef CONFIG_SRCU
static DEFINE_MUTEX(device_links_lock);
DEFINE_STATIC_SRCU(device_links_srcu);

static inline void device_links_write_lock(void)
{
	mutex_lock(&device_links_lock);
}

static inline void device_links_write_unlock(void)
{
	mutex_unlock(&device_links_lock);
}

int device_links_read_lock(void) __acquires(&device_links_srcu)
{
	return srcu_read_lock(&device_links_srcu);
}

void device_links_read_unlock(int idx) __releases(&device_links_srcu)
{
	srcu_read_unlock(&device_links_srcu, idx);
}

int device_links_read_lock_held(void)
{
	return srcu_read_lock_held(&device_links_srcu);
}
#else /* !CONFIG_SRCU */
static DECLARE_RWSEM(device_links_lock);

static inline void device_links_write_lock(void)
{
	down_write(&device_links_lock);
}

static inline void device_links_write_unlock(void)
{
	up_write(&device_links_lock);
}

int device_links_read_lock(void)
{
	down_read(&device_links_lock);
	return 0;
}

void device_links_read_unlock(int not_used)
{
	up_read(&device_links_lock);
}

#ifdef CONFIG_DEBUG_LOCK_ALLOC
int device_links_read_lock_held(void)
{
	return lockdep_is_held(&device_links_lock);
}
#endif
#endif /* !CONFIG_SRCU */

/**
 * device_is_dependent - Check if one device depends on another one
 * @dev: Device to check dependencies for.
 * @target: Device to check against.
 *
 * Check if @target depends on @dev or any device dependent on it (its child or
 * its consumer etc).  Return 1 if that is the case or 0 otherwise.
 */
static int device_is_dependent(struct device *dev, void *target)
{
	struct device_link *link;
	int ret;

	if (dev == target)
		return 1;

	ret = device_for_each_child(dev, target, device_is_dependent);
	if (ret)
		return ret;

	list_for_each_entry(link, &dev->links.consumers, s_node) {
		if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
			continue;

		if (link->consumer == target)
			return 1;

		ret = device_is_dependent(link->consumer, target);
		if (ret)
			break;
	}
	return ret;
}

static void device_link_init_status(struct device_link *link,
				    struct device *consumer,
				    struct device *supplier)
{
	switch (supplier->links.status) {
	case DL_DEV_PROBING:
		switch (consumer->links.status) {
		case DL_DEV_PROBING:
			/*
			 * A consumer driver can create a link to a supplier
			 * that has not completed its probing yet as long as it
			 * knows that the supplier is already functional (for
			 * example, it has just acquired some resources from the
			 * supplier).
			 */
			link->status = DL_STATE_CONSUMER_PROBE;
			break;
		default:
			link->status = DL_STATE_DORMANT;
			break;
		}
		break;
	case DL_DEV_DRIVER_BOUND:
		switch (consumer->links.status) {
		case DL_DEV_PROBING:
			link->status = DL_STATE_CONSUMER_PROBE;
			break;
		case DL_DEV_DRIVER_BOUND:
			link->status = DL_STATE_ACTIVE;
			break;
		default:
			link->status = DL_STATE_AVAILABLE;
			break;
		}
		break;
	case DL_DEV_UNBINDING:
		link->status = DL_STATE_SUPPLIER_UNBIND;
		break;
	default:
		link->status = DL_STATE_DORMANT;
		break;
	}
}

static int device_reorder_to_tail(struct device *dev, void *not_used)
{
	struct device_link *link;

	/*
	 * Devices that have not been registered yet will be put to the ends
	 * of the lists during the registration, so skip them here.
	 */
	if (device_is_registered(dev))
		devices_kset_move_last(dev);

	if (device_pm_initialized(dev))
		device_pm_move_last(dev);

	device_for_each_child(dev, NULL, device_reorder_to_tail);
	list_for_each_entry(link, &dev->links.consumers, s_node) {
		if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
			continue;
		device_reorder_to_tail(link->consumer, NULL);
	}

	return 0;
}

/**
 * device_pm_move_to_tail - Move set of devices to the end of device lists
 * @dev: Device to move
 *
 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
 *
 * It moves the @dev along with all of its children and all of its consumers
 * to the ends of the device_kset and dpm_list, recursively.
 */
void device_pm_move_to_tail(struct device *dev)
{
	int idx;

	idx = device_links_read_lock();
	device_pm_lock();
	device_reorder_to_tail(dev, NULL);
	device_pm_unlock();
	device_links_read_unlock(idx);
}

#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
			       DL_FLAG_AUTOREMOVE_SUPPLIER | \
			       DL_FLAG_AUTOPROBE_CONSUMER  | \
			       DL_FLAG_SYNC_STATE_ONLY)

#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
			    DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)

/**
 * device_link_add - Create a link between two devices.
 * @consumer: Consumer end of the link.
 * @supplier: Supplier end of the link.
 * @flags: Link flags.
 *
 * The caller is responsible for the proper synchronization of the link creation
 * with runtime PM.  First, setting the DL_FLAG_PM_RUNTIME flag will cause the
 * runtime PM framework to take the link into account.  Second, if the
 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
 * be forced into the active metastate and reference-counted upon the creation
 * of the link.  If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
 * ignored.
 *
 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
 * expected to release the link returned by it directly with the help of either
 * device_link_del() or device_link_remove().
 *
 * If that flag is not set, however, the caller of this function is handing the
 * management of the link over to the driver core entirely and its return value
 * can only be used to check whether or not the link is present.  In that case,
 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
 * flags can be used to indicate to the driver core when the link can be safely
 * deleted.  Namely, setting one of them in @flags indicates to the driver core
 * that the link is not going to be used (by the given caller of this function)
 * after unbinding the consumer or supplier driver, respectively, from its
 * device, so the link can be deleted at that point.  If none of them is set,
 * the link will be maintained until one of the devices pointed to by it (either
 * the consumer or the supplier) is unregistered.
 *
 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
 * be used to request the driver core to automaticall probe for a consmer
 * driver after successfully binding a driver to the supplier device.
 *
 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
 * the same time is invalid and will cause NULL to be returned upfront.
 * However, if a device link between the given @consumer and @supplier pair
 * exists already when this function is called for them, the existing link will
 * be returned regardless of its current type and status (the link's flags may
 * be modified then).  The caller of this function is then expected to treat
 * the link as though it has just been created, so (in particular) if
 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
 * explicitly when not needed any more (as stated above).
 *
 * A side effect of the link creation is re-ordering of dpm_list and the
 * devices_kset list by moving the consumer device and all devices depending
 * on it to the ends of these lists (that does not happen to devices that have
 * not been registered when this function is called).
 *
 * The supplier device is required to be registered when this function is called
 * and NULL will be returned if that is not the case.  The consumer device need
 * not be registered, however.
 */
struct device_link *device_link_add(struct device *consumer,
				    struct device *supplier, u32 flags)
{
	struct device_link *link;

	if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS ||
	    (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
	    (flags & DL_FLAG_SYNC_STATE_ONLY &&
	     flags != DL_FLAG_SYNC_STATE_ONLY) ||
	    (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
	     flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
		      DL_FLAG_AUTOREMOVE_SUPPLIER)))
		return NULL;

	if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
		if (pm_runtime_get_sync(supplier) < 0) {
			pm_runtime_put_noidle(supplier);
			return NULL;
		}
	}

	if (!(flags & DL_FLAG_STATELESS))
		flags |= DL_FLAG_MANAGED;

	device_links_write_lock();
	device_pm_lock();

	/*
	 * If the supplier has not been fully registered yet or there is a
	 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
	 * the supplier already in the graph, return NULL. If the link is a
	 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
	 * because it only affects sync_state() callbacks.
	 */
	if (!device_pm_initialized(supplier)
	    || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
		  device_is_dependent(consumer, supplier))) {
		link = NULL;
		goto out;
	}

	/*
	 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
	 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
	 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
	 */
	if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
		flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;

	list_for_each_entry(link, &supplier->links.consumers, s_node) {
		if (link->consumer != consumer)
			continue;

		if (flags & DL_FLAG_PM_RUNTIME) {
			if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
				pm_runtime_new_link(consumer);
				link->flags |= DL_FLAG_PM_RUNTIME;
			}
			if (flags & DL_FLAG_RPM_ACTIVE)
				refcount_inc(&link->rpm_active);
		}

		if (flags & DL_FLAG_STATELESS) {
			kref_get(&link->kref);
			if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
			    !(link->flags & DL_FLAG_STATELESS)) {
				link->flags |= DL_FLAG_STATELESS;
				goto reorder;
			} else {
				goto out;
			}
		}

		/*
		 * If the life time of the link following from the new flags is
		 * longer than indicated by the flags of the existing link,
		 * update the existing link to stay around longer.
		 */
		if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
			if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
				link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
				link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
			}
		} else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
			link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
					 DL_FLAG_AUTOREMOVE_SUPPLIER);
		}
		if (!(link->flags & DL_FLAG_MANAGED)) {
			kref_get(&link->kref);
			link->flags |= DL_FLAG_MANAGED;
			device_link_init_status(link, consumer, supplier);
		}
		if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
		    !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
			link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
			goto reorder;
		}

		goto out;
	}

	link = kzalloc(sizeof(*link), GFP_KERNEL);
	if (!link)
		goto out;

	refcount_set(&link->rpm_active, 1);

	if (flags & DL_FLAG_PM_RUNTIME) {
		if (flags & DL_FLAG_RPM_ACTIVE)
			refcount_inc(&link->rpm_active);

		pm_runtime_new_link(consumer);
	}

	get_device(supplier);
	link->supplier = supplier;
	INIT_LIST_HEAD(&link->s_node);
	get_device(consumer);
	link->consumer = consumer;
	INIT_LIST_HEAD(&link->c_node);
	link->flags = flags;
	kref_init(&link->kref);

	/* Determine the initial link state. */
	if (flags & DL_FLAG_STATELESS)
		link->status = DL_STATE_NONE;
	else
		device_link_init_status(link, consumer, supplier);

	/*
	 * Some callers expect the link creation during consumer driver probe to
	 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
	 */
	if (link->status == DL_STATE_CONSUMER_PROBE &&
	    flags & DL_FLAG_PM_RUNTIME)
		pm_runtime_resume(supplier);

	if (flags & DL_FLAG_SYNC_STATE_ONLY) {
		dev_dbg(consumer,
			"Linked as a sync state only consumer to %s\n",
			dev_name(supplier));
		goto out;
	}
reorder:
	/*
	 * Move the consumer and all of the devices depending on it to the end
	 * of dpm_list and the devices_kset list.
	 *
	 * It is necessary to hold dpm_list locked throughout all that or else
	 * we may end up suspending with a wrong ordering of it.
	 */
	device_reorder_to_tail(consumer, NULL);

	list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
	list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);

	dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));

 out:
	device_pm_unlock();
	device_links_write_unlock();

	if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
		pm_runtime_put(supplier);

	return link;
}
EXPORT_SYMBOL_GPL(device_link_add);

/**
 * device_link_wait_for_supplier - Add device to wait_for_suppliers list
 * @consumer: Consumer device
 *
 * Marks the @consumer device as waiting for suppliers to become available by
 * adding it to the wait_for_suppliers list. The consumer device will never be
 * probed until it's removed from the wait_for_suppliers list.
 *
 * The caller is responsible for adding the links to the supplier devices once
 * they are available and removing the @consumer device from the
 * wait_for_suppliers list once links to all the suppliers have been created.
 *
 * This function is NOT meant to be called from the probe function of the
 * consumer but rather from code that creates/adds the consumer device.
 */
static void device_link_wait_for_supplier(struct device *consumer,
					  bool need_for_probe)
{
	mutex_lock(&wfs_lock);
	list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers);
	consumer->links.need_for_probe = need_for_probe;
	mutex_unlock(&wfs_lock);
}

static void device_link_wait_for_mandatory_supplier(struct device *consumer)
{
	device_link_wait_for_supplier(consumer, true);
}

static void device_link_wait_for_optional_supplier(struct device *consumer)
{
	device_link_wait_for_supplier(consumer, false);
}

/**
 * device_link_add_missing_supplier_links - Add links from consumer devices to
 *					    supplier devices, leaving any
 *					    consumer with inactive suppliers on
 *					    the wait_for_suppliers list
 *
 * Loops through all consumers waiting on suppliers and tries to add all their
 * supplier links. If that succeeds, the consumer device is removed from
 * wait_for_suppliers list. Otherwise, they are left in the wait_for_suppliers
 * list.  Devices left on the wait_for_suppliers list will not be probed.
 *
 * The fwnode add_links callback is expected to return 0 if it has found and
 * added all the supplier links for the consumer device. It should return an
 * error if it isn't able to do so.
 *
 * The caller of device_link_wait_for_supplier() is expected to call this once
 * it's aware of potential suppliers becoming available.
 */
static void device_link_add_missing_supplier_links(void)
{
	struct device *dev, *tmp;

	mutex_lock(&wfs_lock);
	list_for_each_entry_safe(dev, tmp, &wait_for_suppliers,
				 links.needs_suppliers) {
		int ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
		if (!ret)
			list_del_init(&dev->links.needs_suppliers);
		else if (ret != -ENODEV)
			dev->links.need_for_probe = false;
	}
	mutex_unlock(&wfs_lock);
}

static void device_link_free(struct device_link *link)
{
	while (refcount_dec_not_one(&link->rpm_active))
		pm_runtime_put(link->supplier);

	put_device(link->consumer);
	put_device(link->supplier);
	kfree(link);
}

#ifdef CONFIG_SRCU
static void __device_link_free_srcu(struct rcu_head *rhead)
{
	device_link_free(container_of(rhead, struct device_link, rcu_head));
}

static void __device_link_del(struct kref *kref)
{
	struct device_link *link = container_of(kref, struct device_link, kref);

	dev_dbg(link->consumer, "Dropping the link to %s\n",
		dev_name(link->supplier));

	if (link->flags & DL_FLAG_PM_RUNTIME)
		pm_runtime_drop_link(link->consumer);

	list_del_rcu(&link->s_node);
	list_del_rcu(&link->c_node);
	call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
}
#else /* !CONFIG_SRCU */
static void __device_link_del(struct kref *kref)
{
	struct device_link *link = container_of(kref, struct device_link, kref);

	dev_info(link->consumer, "Dropping the link to %s\n",
		 dev_name(link->supplier));

	if (link->flags & DL_FLAG_PM_RUNTIME)
		pm_runtime_drop_link(link->consumer);

	list_del(&link->s_node);
	list_del(&link->c_node);
	device_link_free(link);
}
#endif /* !CONFIG_SRCU */

static void device_link_put_kref(struct device_link *link)
{
	if (link->flags & DL_FLAG_STATELESS)
		kref_put(&link->kref, __device_link_del);
	else
		WARN(1, "Unable to drop a managed device link reference\n");
}

/**
 * device_link_del - Delete a stateless link between two devices.
 * @link: Device link to delete.
 *
 * The caller must ensure proper synchronization of this function with runtime
 * PM.  If the link was added multiple times, it needs to be deleted as often.
 * Care is required for hotplugged devices:  Their links are purged on removal
 * and calling device_link_del() is then no longer allowed.
 */
void device_link_del(struct device_link *link)
{
	device_links_write_lock();
	device_pm_lock();
	device_link_put_kref(link);
	device_pm_unlock();
	device_links_write_unlock();
}
EXPORT_SYMBOL_GPL(device_link_del);

/**
 * device_link_remove - Delete a stateless link between two devices.
 * @consumer: Consumer end of the link.
 * @supplier: Supplier end of the link.
 *
 * The caller must ensure proper synchronization of this function with runtime
 * PM.
 */
void device_link_remove(void *consumer, struct device *supplier)
{
	struct device_link *link;

	if (WARN_ON(consumer == supplier))
		return;

	device_links_write_lock();
	device_pm_lock();

	list_for_each_entry(link, &supplier->links.consumers, s_node) {
		if (link->consumer == consumer) {
			device_link_put_kref(link);
			break;
		}
	}

	device_pm_unlock();
	device_links_write_unlock();
}
EXPORT_SYMBOL_GPL(device_link_remove);

static void device_links_missing_supplier(struct device *dev)
{
	struct device_link *link;

	list_for_each_entry(link, &dev->links.suppliers, c_node)
		if (link->status == DL_STATE_CONSUMER_PROBE)
			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
}

/**
 * device_links_check_suppliers - Check presence of supplier drivers.
 * @dev: Consumer device.
 *
 * Check links from this device to any suppliers.  Walk the list of the device's
 * links to suppliers and see if all of them are available.  If not, simply
 * return -EPROBE_DEFER.
 *
 * We need to guarantee that the supplier will not go away after the check has
 * been positive here.  It only can go away in __device_release_driver() and
 * that function  checks the device's links to consumers.  This means we need to
 * mark the link as "consumer probe in progress" to make the supplier removal
 * wait for us to complete (or bad things may happen).
 *
 * Links without the DL_FLAG_MANAGED flag set are ignored.
 */
int device_links_check_suppliers(struct device *dev)
{
	struct device_link *link;
	int ret = 0;

	/*
	 * Device waiting for supplier to become available is not allowed to
	 * probe.
	 */
	mutex_lock(&wfs_lock);
	if (!list_empty(&dev->links.needs_suppliers) &&
	    dev->links.need_for_probe) {
		mutex_unlock(&wfs_lock);
		return -EPROBE_DEFER;
	}
	mutex_unlock(&wfs_lock);

	device_links_write_lock();

	list_for_each_entry(link, &dev->links.suppliers, c_node) {
		if (!(link->flags & DL_FLAG_MANAGED) ||
		    link->flags & DL_FLAG_SYNC_STATE_ONLY)
			continue;

		if (link->status != DL_STATE_AVAILABLE) {
			device_links_missing_supplier(dev);
			ret = -EPROBE_DEFER;
			break;
		}
		WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
	}
	dev->links.status = DL_DEV_PROBING;

	device_links_write_unlock();
	return ret;
}

/**
 * __device_links_queue_sync_state - Queue a device for sync_state() callback
 * @dev: Device to call sync_state() on
 * @list: List head to queue the @dev on
 *
 * Queues a device for a sync_state() callback when the device links write lock
 * isn't held. This allows the sync_state() execution flow to use device links
 * APIs.  The caller must ensure this function is called with
 * device_links_write_lock() held.
 *
 * This function does a get_device() to make sure the device is not freed while
 * on this list.
 *
 * So the caller must also ensure that device_links_flush_sync_list() is called
 * as soon as the caller releases device_links_write_lock().  This is necessary
 * to make sure the sync_state() is called in a timely fashion and the
 * put_device() is called on this device.
 */
static void __device_links_queue_sync_state(struct device *dev,
					    struct list_head *list)
{
	struct device_link *link;

	if (!dev_has_sync_state(dev))
		return;
	if (dev->state_synced)
		return;

	list_for_each_entry(link, &dev->links.consumers, s_node) {
		if (!(link->flags & DL_FLAG_MANAGED))
			continue;
		if (link->status != DL_STATE_ACTIVE)
			return;
	}

	/*
	 * Set the flag here to avoid adding the same device to a list more
	 * than once. This can happen if new consumers get added to the device
	 * and probed before the list is flushed.
	 */
	dev->state_synced = true;

	if (WARN_ON(!list_empty(&dev->links.defer_sync)))
		return;

	get_device(dev);
	list_add_tail(&dev->links.defer_sync, list);
}

/**
 * device_links_flush_sync_list - Call sync_state() on a list of devices
 * @list: List of devices to call sync_state() on
 * @dont_lock_dev: Device for which lock is already held by the caller
 *
 * Calls sync_state() on all the devices that have been queued for it. This
 * function is used in conjunction with __device_links_queue_sync_state(). The
 * @dont_lock_dev parameter is useful when this function is called from a
 * context where a device lock is already held.
 */
static void device_links_flush_sync_list(struct list_head *list,
					 struct device *dont_lock_dev)
{
	struct device *dev, *tmp;

	list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
		list_del_init(&dev->links.defer_sync);

		if (dev != dont_lock_dev)
			device_lock(dev);

		if (dev->bus->sync_state)
			dev->bus->sync_state(dev);
		else if (dev->driver && dev->driver->sync_state)
			dev->driver->sync_state(dev);

		if (dev != dont_lock_dev)
			device_unlock(dev);

		put_device(dev);
	}
}

void device_links_supplier_sync_state_pause(void)
{
	device_links_write_lock();
	defer_sync_state_count++;
	device_links_write_unlock();
}

void device_links_supplier_sync_state_resume(void)
{
	struct device *dev, *tmp;
	LIST_HEAD(sync_list);

	device_links_write_lock();
	if (!defer_sync_state_count) {
		WARN(true, "Unmatched sync_state pause/resume!");
		goto out;
	}
	defer_sync_state_count--;
	if (defer_sync_state_count)
		goto out;

	list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
		/*
		 * Delete from deferred_sync list before queuing it to
		 * sync_list because defer_sync is used for both lists.
		 */
		list_del_init(&dev->links.defer_sync);
		__device_links_queue_sync_state(dev, &sync_list);
	}
out:
	device_links_write_unlock();

	device_links_flush_sync_list(&sync_list, NULL);
}

static int sync_state_resume_initcall(void)
{
	device_links_supplier_sync_state_resume();
	return 0;
}
late_initcall(sync_state_resume_initcall);

static void __device_links_supplier_defer_sync(struct device *sup)
{
	if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
		list_add_tail(&sup->links.defer_sync, &deferred_sync);
}

/**
 * device_links_driver_bound - Update device links after probing its driver.
 * @dev: Device to update the links for.
 *
 * The probe has been successful, so update links from this device to any
 * consumers by changing their status to "available".
 *
 * Also change the status of @dev's links to suppliers to "active".
 *
 * Links without the DL_FLAG_MANAGED flag set are ignored.
 */
void device_links_driver_bound(struct device *dev)
{
	struct device_link *link;
	LIST_HEAD(sync_list);

	/*
	 * If a device probes successfully, it's expected to have created all
	 * the device links it needs to or make new device links as it needs
	 * them. So, it no longer needs to wait on any suppliers.
	 */
	mutex_lock(&wfs_lock);
	list_del_init(&dev->links.needs_suppliers);
	mutex_unlock(&wfs_lock);

	device_links_write_lock();

	list_for_each_entry(link, &dev->links.consumers, s_node) {
		if (!(link->flags & DL_FLAG_MANAGED))
			continue;

		/*
		 * Links created during consumer probe may be in the "consumer
		 * probe" state to start with if the supplier is still probing
		 * when they are created and they may become "active" if the
		 * consumer probe returns first.  Skip them here.
		 */
		if (link->status == DL_STATE_CONSUMER_PROBE ||
		    link->status == DL_STATE_ACTIVE)
			continue;

		WARN_ON(link->status != DL_STATE_DORMANT);
		WRITE_ONCE(link->status, DL_STATE_AVAILABLE);

		if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
			driver_deferred_probe_add(link->consumer);
	}

	if (defer_sync_state_count)
		__device_links_supplier_defer_sync(dev);
	else
		__device_links_queue_sync_state(dev, &sync_list);

	list_for_each_entry(link, &dev->links.suppliers, c_node) {
		if (!(link->flags & DL_FLAG_MANAGED))
			continue;

		WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
		WRITE_ONCE(link->status, DL_STATE_ACTIVE);

		if (defer_sync_state_count)
			__device_links_supplier_defer_sync(link->supplier);
		else
			__device_links_queue_sync_state(link->supplier,
							&sync_list);
	}

	dev->links.status = DL_DEV_DRIVER_BOUND;

	device_links_write_unlock();

	device_links_flush_sync_list(&sync_list, dev);
}

static void device_link_drop_managed(struct device_link *link)
{
	link->flags &= ~DL_FLAG_MANAGED;
	WRITE_ONCE(link->status, DL_STATE_NONE);
	kref_put(&link->kref, __device_link_del);
}

/**
 * __device_links_no_driver - Update links of a device without a driver.
 * @dev: Device without a drvier.
 *
 * Delete all non-persistent links from this device to any suppliers.
 *
 * Persistent links stay around, but their status is changed to "available",
 * unless they already are in the "supplier unbind in progress" state in which
 * case they need not be updated.
 *
 * Links without the DL_FLAG_MANAGED flag set are ignored.
 */
static void __device_links_no_driver(struct device *dev)
{
	struct device_link *link, *ln;

	list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
		if (!(link->flags & DL_FLAG_MANAGED))
			continue;

		if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
			device_link_drop_managed(link);
		else if (link->status == DL_STATE_CONSUMER_PROBE ||
			 link->status == DL_STATE_ACTIVE)
			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
	}

	dev->links.status = DL_DEV_NO_DRIVER;
}

/**
 * device_links_no_driver - Update links after failing driver probe.
 * @dev: Device whose driver has just failed to probe.
 *
 * Clean up leftover links to consumers for @dev and invoke
 * %__device_links_no_driver() to update links to suppliers for it as
 * appropriate.
 *
 * Links without the DL_FLAG_MANAGED flag set are ignored.
 */
void device_links_no_driver(struct device *dev)
{
	struct device_link *link;

	device_links_write_lock();

	list_for_each_entry(link, &dev->links.consumers, s_node) {
		if (!(link->flags & DL_FLAG_MANAGED))
			continue;

		/*
		 * The probe has failed, so if the status of the link is
		 * "consumer probe" or "active", it must have been added by
		 * a probing consumer while this device was still probing.
		 * Change its state to "dormant", as it represents a valid
		 * relationship, but it is not functionally meaningful.
		 */
		if (link->status == DL_STATE_CONSUMER_PROBE ||
		    link->status == DL_STATE_ACTIVE)
			WRITE_ONCE(link->status, DL_STATE_DORMANT);
	}

	__device_links_no_driver(dev);

	device_links_write_unlock();
}

/**
 * device_links_driver_cleanup - Update links after driver removal.
 * @dev: Device whose driver has just gone away.
 *
 * Update links to consumers for @dev by changing their status to "dormant" and
 * invoke %__device_links_no_driver() to update links to suppliers for it as
 * appropriate.
 *
 * Links without the DL_FLAG_MANAGED flag set are ignored.
 */
void device_links_driver_cleanup(struct device *dev)
{
	struct device_link *link, *ln;

	device_links_write_lock();

	list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
		if (!(link->flags & DL_FLAG_MANAGED))
			continue;

		WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
		WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);

		/*
		 * autoremove the links between this @dev and its consumer
		 * devices that are not active, i.e. where the link state
		 * has moved to DL_STATE_SUPPLIER_UNBIND.
		 */
		if (link->status == DL_STATE_SUPPLIER_UNBIND &&
		    link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
			device_link_drop_managed(link);

		WRITE_ONCE(link->status, DL_STATE_DORMANT);
	}

	list_del_init(&dev->links.defer_sync);
	__device_links_no_driver(dev);

	device_links_write_unlock();
}

/**
 * device_links_busy - Check if there are any busy links to consumers.
 * @dev: Device to check.
 *
 * Check each consumer of the device and return 'true' if its link's status
 * is one of "consumer probe" or "active" (meaning that the given consumer is
 * probing right now or its driver is present).  Otherwise, change the link
 * state to "supplier unbind" to prevent the consumer from being probed
 * successfully going forward.
 *
 * Return 'false' if there are no probing or active consumers.
 *
 * Links without the DL_FLAG_MANAGED flag set are ignored.
 */
bool device_links_busy(struct device *dev)
{
	struct device_link *link;
	bool ret = false;

	device_links_write_lock();

	list_for_each_entry(link, &dev->links.consumers, s_node) {
		if (!(link->flags & DL_FLAG_MANAGED))
			continue;

		if (link->status == DL_STATE_CONSUMER_PROBE
		    || link->status == DL_STATE_ACTIVE) {
			ret = true;
			break;
		}
		WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
	}

	dev->links.status = DL_DEV_UNBINDING;

	device_links_write_unlock();
	return ret;
}

/**
 * device_links_unbind_consumers - Force unbind consumers of the given device.
 * @dev: Device to unbind the consumers of.
 *
 * Walk the list of links to consumers for @dev and if any of them is in the
 * "consumer probe" state, wait for all device probes in progress to complete
 * and start over.
 *
 * If that's not the case, change the status of the link to "supplier unbind"
 * and check if the link was in the "active" state.  If so, force the consumer
 * driver to unbind and start over (the consumer will not re-probe as we have
 * changed the state of the link already).
 *
 * Links without the DL_FLAG_MANAGED flag set are ignored.
 */
void device_links_unbind_consumers(struct device *dev)
{
	struct device_link *link;

 start:
	device_links_write_lock();

	list_for_each_entry(link, &dev->links.consumers, s_node) {
		enum device_link_state status;

		if (!(link->flags & DL_FLAG_MANAGED) ||
		    link->flags & DL_FLAG_SYNC_STATE_ONLY)
			continue;

		status = link->status;
		if (status == DL_STATE_CONSUMER_PROBE) {
			device_links_write_unlock();

			wait_for_device_probe();
			goto start;
		}
		WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
		if (status == DL_STATE_ACTIVE) {
			struct device *consumer = link->consumer;

			get_device(consumer);

			device_links_write_unlock();

			device_release_driver_internal(consumer, NULL,
						       consumer->parent);
			put_device(consumer);
			goto start;
		}
	}

	device_links_write_unlock();
}

/**
 * device_links_purge - Delete existing links to other devices.
 * @dev: Target device.
 */
static void device_links_purge(struct device *dev)
{
	struct device_link *link, *ln;

	mutex_lock(&wfs_lock);
	list_del(&dev->links.needs_suppliers);
	mutex_unlock(&wfs_lock);

	/*
	 * Delete all of the remaining links from this device to any other
	 * devices (either consumers or suppliers).
	 */
	device_links_write_lock();

	list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
		WARN_ON(link->status == DL_STATE_ACTIVE);
		__device_link_del(&link->kref);
	}

	list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
		WARN_ON(link->status != DL_STATE_DORMANT &&
			link->status != DL_STATE_NONE);
		__device_link_del(&link->kref);
	}

	device_links_write_unlock();
}

/* Device links support end. */

int (*platform_notify)(struct device *dev) = NULL;
int (*platform_notify_remove)(struct device *dev) = NULL;
static struct kobject *dev_kobj;
struct kobject *sysfs_dev_char_kobj;
struct kobject *sysfs_dev_block_kobj;

static DEFINE_MUTEX(device_hotplug_lock);

void lock_device_hotplug(void)
{
	mutex_lock(&device_hotplug_lock);
}

void unlock_device_hotplug(void)
{
	mutex_unlock(&device_hotplug_lock);
}

int lock_device_hotplug_sysfs(void)
{
	if (mutex_trylock(&device_hotplug_lock))
		return 0;

	/* Avoid busy looping (5 ms of sleep should do). */
	msleep(5);
	return restart_syscall();
}

#ifdef CONFIG_BLOCK
static inline int device_is_not_partition(struct device *dev)
{
	return !(dev->type == &part_type);
}
#else
static inline int device_is_not_partition(struct device *dev)
{
	return 1;
}
#endif

static int
device_platform_notify(struct device *dev, enum kobject_action action)
{
	int ret;

	ret = acpi_platform_notify(dev, action);
	if (ret)
		return ret;

	ret = software_node_notify(dev, action);
	if (ret)
		return ret;

	if (platform_notify && action == KOBJ_ADD)
		platform_notify(dev);
	else if (platform_notify_remove && action == KOBJ_REMOVE)
		platform_notify_remove(dev);
	return 0;
}

/**
 * dev_driver_string - Return a device's driver name, if at all possible
 * @dev: struct device to get the name of
 *
 * Will return the device's driver's name if it is bound to a device.  If
 * the device is not bound to a driver, it will return the name of the bus
 * it is attached to.  If it is not attached to a bus either, an empty
 * string will be returned.
 */
const char *dev_driver_string(const struct device *dev)
{
	struct device_driver *drv;

	/* dev->driver can change to NULL underneath us because of unbinding,
	 * so be careful about accessing it.  dev->bus and dev->class should
	 * never change once they are set, so they don't need special care.
	 */
	drv = READ_ONCE(dev->driver);
	return drv ? drv->name :
			(dev->bus ? dev->bus->name :
			(dev->class ? dev->class->name : ""));
}
EXPORT_SYMBOL(dev_driver_string);

#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)

static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
			     char *buf)
{
	struct device_attribute *dev_attr = to_dev_attr(attr);
	struct device *dev = kobj_to_dev(kobj);
	ssize_t ret = -EIO;

	if (dev_attr->show)
		ret = dev_attr->show(dev, dev_attr, buf);
	if (ret >= (ssize_t)PAGE_SIZE) {
		printk("dev_attr_show: %pS returned bad count\n",
				dev_attr->show);
	}
	return ret;
}

static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
			      const char *buf, size_t count)
{
	struct device_attribute *dev_attr = to_dev_attr(attr);
	struct device *dev = kobj_to_dev(kobj);
	ssize_t ret = -EIO;

	if (dev_attr->store)
		ret = dev_attr->store(dev, dev_attr, buf, count);
	return ret;
}

static const struct sysfs_ops dev_sysfs_ops = {
	.show	= dev_attr_show,
	.store	= dev_attr_store,
};

#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)

ssize_t device_store_ulong(struct device *dev,
			   struct device_attribute *attr,
			   const char *buf, size_t size)
{
	struct dev_ext_attribute *ea = to_ext_attr(attr);
	int ret;
	unsigned long new;

	ret = kstrtoul(buf, 0, &new);
	if (ret)
		return ret;
	*(unsigned long *)(ea->var) = new;
	/* Always return full write size even if we didn't consume all */
	return size;
}
EXPORT_SYMBOL_GPL(device_store_ulong);

ssize_t device_show_ulong(struct device *dev,
			  struct device_attribute *attr,
			  char *buf)
{
	struct dev_ext_attribute *ea = to_ext_attr(attr);
	return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
}
EXPORT_SYMBOL_GPL(device_show_ulong);

ssize_t device_store_int(struct device *dev,
			 struct device_attribute *attr,
			 const char *buf, size_t size)
{
	struct dev_ext_attribute *ea = to_ext_attr(attr);
	int ret;
	long new;

	ret = kstrtol(buf, 0, &new);
	if (ret)
		return ret;

	if (new > INT_MAX || new < INT_MIN)
		return -EINVAL;
	*(int *)(ea->var) = new;
	/* Always return full write size even if we didn't consume all */
	return size;
}
EXPORT_SYMBOL_GPL(device_store_int);

ssize_t device_show_int(struct device *dev,
			struct device_attribute *attr,
			char *buf)
{
	struct dev_ext_attribute *ea = to_ext_attr(attr);

	return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
}
EXPORT_SYMBOL_GPL(device_show_int);

ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
			  const char *buf, size_t size)
{
	struct dev_ext_attribute *ea = to_ext_attr(attr);

	if (strtobool(buf, ea->var) < 0)
		return -EINVAL;

	return size;
}
EXPORT_SYMBOL_GPL(device_store_bool);

ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	struct dev_ext_attribute *ea = to_ext_attr(attr);

	return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
}
EXPORT_SYMBOL_GPL(device_show_bool);

/**
 * device_release - free device structure.
 * @kobj: device's kobject.
 *
 * This is called once the reference count for the object
 * reaches 0. We forward the call to the device's release
 * method, which should handle actually freeing the structure.
 */
static void device_release(struct kobject *kobj)
{
	struct device *dev = kobj_to_dev(kobj);
	struct device_private *p = dev->p;

	/*
	 * Some platform devices are driven without driver attached
	 * and managed resources may have been acquired.  Make sure
	 * all resources are released.
	 *
	 * Drivers still can add resources into device after device
	 * is deleted but alive, so release devres here to avoid
	 * possible memory leak.
	 */
	devres_release_all(dev);

	if (dev->release)
		dev->release(dev);
	else if (dev->type && dev->type->release)
		dev->type->release(dev);
	else if (dev->class && dev->class->dev_release)
		dev->class->dev_release(dev);
	else
		WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/kobject.txt.\n",
			dev_name(dev));
	kfree(p);
}

static const void *device_namespace(struct kobject *kobj)
{
	struct device *dev = kobj_to_dev(kobj);
	const void *ns = NULL;

	if (dev->class && dev->class->ns_type)
		ns = dev->class->namespace(dev);

	return ns;
}

static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
{
	struct device *dev = kobj_to_dev(kobj);

	if (dev->class && dev->class->get_ownership)
		dev->class->get_ownership(dev, uid, gid);
}

static struct kobj_type device_ktype = {
	.release	= device_release,
	.sysfs_ops	= &dev_sysfs_ops,
	.namespace	= device_namespace,
	.get_ownership	= device_get_ownership,
};


static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
{
	struct kobj_type *ktype = get_ktype(kobj);

	if (ktype == &device_ktype) {
		struct device *dev = kobj_to_dev(kobj);
		if (dev->bus)
			return 1;
		if (dev->class)
			return 1;
	}
	return 0;
}

static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
{
	struct device *dev = kobj_to_dev(kobj);

	if (dev->bus)
		return dev->bus->name;
	if (dev->class)
		return dev->class->name;
	return NULL;
}

static int dev_uevent(struct kset *kset, struct kobject *kobj,
		      struct kobj_uevent_env *env)
{
	struct device *dev = kobj_to_dev(kobj);
	int retval = 0;

	/* add device node properties if present */
	if (MAJOR(dev->devt)) {
		const char *tmp;
		const char *name;
		umode_t mode = 0;
		kuid_t uid = GLOBAL_ROOT_UID;
		kgid_t gid = GLOBAL_ROOT_GID;

		add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
		add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
		name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
		if (name) {
			add_uevent_var(env, "DEVNAME=%s", name);
			if (mode)
				add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
			if (!uid_eq(uid, GLOBAL_ROOT_UID))
				add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
			if (!gid_eq(gid, GLOBAL_ROOT_GID))
				add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
			kfree(tmp);
		}
	}

	if (dev->type && dev->type->name)
		add_uevent_var(env, "DEVTYPE=%s", dev->type->name);

	if (dev->driver)
		add_uevent_var(env, "DRIVER=%s", dev->driver->name);

	/* Add common DT information about the device */
	of_device_uevent(dev, env);

	/* have the bus specific function add its stuff */
	if (dev->bus && dev->bus->uevent) {
		retval = dev->bus->uevent(dev, env);
		if (retval)
			pr_debug("device: '%s': %s: bus uevent() returned %d\n",
				 dev_name(dev), __func__, retval);
	}

	/* have the class specific function add its stuff */
	if (dev->class && dev->class->dev_uevent) {
		retval = dev->class->dev_uevent(dev, env);
		if (retval)
			pr_debug("device: '%s': %s: class uevent() "
				 "returned %d\n", dev_name(dev),
				 __func__, retval);
	}

	/* have the device type specific function add its stuff */
	if (dev->type && dev->type->uevent) {
		retval = dev->type->uevent(dev, env);
		if (retval)
			pr_debug("device: '%s': %s: dev_type uevent() "
				 "returned %d\n", dev_name(dev),
				 __func__, retval);
	}

	return retval;
}

static const struct kset_uevent_ops device_uevent_ops = {
	.filter =	dev_uevent_filter,
	.name =		dev_uevent_name,
	.uevent =	dev_uevent,
};

static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
			   char *buf)
{
	struct kobject *top_kobj;
	struct kset *kset;
	struct kobj_uevent_env *env = NULL;
	int i;
	size_t count = 0;
	int retval;

	/* search the kset, the device belongs to */
	top_kobj = &dev->kobj;
	while (!top_kobj->kset && top_kobj->parent)
		top_kobj = top_kobj->parent;
	if (!top_kobj->kset)
		goto out;

	kset = top_kobj->kset;
	if (!kset->uevent_ops || !kset->uevent_ops->uevent)
		goto out;

	/* respect filter */
	if (kset->uevent_ops && kset->uevent_ops->filter)
		if (!kset->uevent_ops->filter(kset, &dev->kobj))
			goto out;

	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
	if (!env)
		return -ENOMEM;

	/* let the kset specific function add its keys */
	retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
	if (retval)
		goto out;

	/* copy keys to file */
	for (i = 0; i < env->envp_idx; i++)
		count += sprintf(&buf[count], "%s\n", env->envp[i]);
out:
	kfree(env);
	return count;
}

static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
	int rc;

	rc = kobject_synth_uevent(&dev->kobj, buf, count);

	if (rc) {
		dev_err(dev, "uevent: failed to send synthetic uevent\n");
		return rc;
	}

	return count;
}
static DEVICE_ATTR_RW(uevent);

static ssize_t online_show(struct device *dev, struct device_attribute *attr,
			   char *buf)
{
	bool val;

	device_lock(dev);
	val = !dev->offline;
	device_unlock(dev);
	return sprintf(buf, "%u\n", val);
}

static ssize_t online_store(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
	bool val;
	int ret;

	ret = strtobool(buf, &val);
	if (ret < 0)
		return ret;

	ret = lock_device_hotplug_sysfs();
	if (ret)
		return ret;

	ret = val ? device_online(dev) : device_offline(dev);
	unlock_device_hotplug();
	return ret < 0 ? ret : count;
}
static DEVICE_ATTR_RW(online);

int device_add_groups(struct device *dev, const struct attribute_group **groups)
{
	return sysfs_create_groups(&dev->kobj, groups);
}
EXPORT_SYMBOL_GPL(device_add_groups);

void device_remove_groups(struct device *dev,
			  const struct attribute_group **groups)
{
	sysfs_remove_groups(&dev->kobj, groups);
}
EXPORT_SYMBOL_GPL(device_remove_groups);

union device_attr_group_devres {
	const struct attribute_group *group;
	const struct attribute_group **groups;
};

static int devm_attr_group_match(struct device *dev, void *res, void *data)
{
	return ((union device_attr_group_devres *)res)->group == data;
}

static void devm_attr_group_remove(struct device *dev, void *res)
{
	union device_attr_group_devres *devres = res;
	const struct attribute_group *group = devres->group;

	dev_dbg(dev, "%s: removing group %p\n", __func__, group);
	sysfs_remove_group(&dev->kobj, group);
}

static void devm_attr_groups_remove(struct device *dev, void *res)
{
	union device_attr_group_devres *devres = res;
	const struct attribute_group **groups = devres->groups;

	dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
	sysfs_remove_groups(&dev->kobj, groups);
}

/**
 * devm_device_add_group - given a device, create a managed attribute group
 * @dev:	The device to create the group for
 * @grp:	The attribute group to create
 *
 * This function creates a group for the first time.  It will explicitly
 * warn and error if any of the attribute files being created already exist.
 *
 * Returns 0 on success or error code on failure.
 */
int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
{
	union device_attr_group_devres *devres;
	int error;

	devres = devres_alloc(devm_attr_group_remove,
			      sizeof(*devres), GFP_KERNEL);
	if (!devres)
		return -ENOMEM;

	error = sysfs_create_group(&dev->kobj, grp);
	if (error) {
		devres_free(devres);
		return error;
	}

	devres->group = grp;
	devres_add(dev, devres);
	return 0;
}
EXPORT_SYMBOL_GPL(devm_device_add_group);

/**
 * devm_device_remove_group: remove a managed group from a device
 * @dev:	device to remove the group from
 * @grp:	group to remove
 *
 * This function removes a group of attributes from a device. The attributes
 * previously have to have been created for this group, otherwise it will fail.
 */
void devm_device_remove_group(struct device *dev,
			      const struct attribute_group *grp)
{
	WARN_ON(devres_release(dev, devm_attr_group_remove,
			       devm_attr_group_match,
			       /* cast away const */ (void *)grp));
}
EXPORT_SYMBOL_GPL(devm_device_remove_group);

/**
 * devm_device_add_groups - create a bunch of managed attribute groups
 * @dev:	The device to create the group for
 * @groups:	The attribute groups to create, NULL terminated
 *
 * This function creates a bunch of managed attribute groups.  If an error
 * occurs when creating a group, all previously created groups will be
 * removed, unwinding everything back to the original state when this
 * function was called.  It will explicitly warn and error if any of the
 * attribute files being created already exist.
 *
 * Returns 0 on success or error code from sysfs_create_group on failure.
 */
int devm_device_add_groups(struct device *dev,
			   const struct attribute_group **groups)
{
	union device_attr_group_devres *devres;
	int error;

	devres = devres_alloc(devm_attr_groups_remove,
			      sizeof(*devres), GFP_KERNEL);
	if (!devres)
		return -ENOMEM;

	error = sysfs_create_groups(&dev->kobj, groups);
	if (error) {
		devres_free(devres);
		return error;
	}

	devres->groups = groups;
	devres_add(dev, devres);
	return 0;
}
EXPORT_SYMBOL_GPL(devm_device_add_groups);

/**
 * devm_device_remove_groups - remove a list of managed groups
 *
 * @dev:	The device for the groups to be removed from
 * @groups:	NULL terminated list of groups to be removed
 *
 * If groups is not NULL, remove the specified groups from the device.
 */
void devm_device_remove_groups(struct device *dev,
			       const struct attribute_group **groups)
{
	WARN_ON(devres_release(dev, devm_attr_groups_remove,
			       devm_attr_group_match,
			       /* cast away const */ (void *)groups));
}
EXPORT_SYMBOL_GPL(devm_device_remove_groups);

static int device_add_attrs(struct device *dev)
{
	struct class *class = dev->class;
	const struct device_type *type = dev->type;
	int error;

	if (class) {
		error = device_add_groups(dev, class->dev_groups);
		if (error)
			return error;
	}

	if (type) {
		error = device_add_groups(dev, type->groups);
		if (error)
			goto err_remove_class_groups;
	}

	error = device_add_groups(dev, dev->groups);
	if (error)
		goto err_remove_type_groups;

	if (device_supports_offline(dev) && !dev->offline_disabled) {
		error = device_create_file(dev, &dev_attr_online);
		if (error)
			goto err_remove_dev_groups;
	}

	return 0;

 err_remove_dev_groups:
	device_remove_groups(dev, dev->groups);
 err_remove_type_groups:
	if (type)
		device_remove_groups(dev, type->groups);
 err_remove_class_groups:
	if (class)
		device_remove_groups(dev, class->dev_groups);

	return error;
}

static void device_remove_attrs(struct device *dev)
{
	struct class *class = dev->class;
	const struct device_type *type = dev->type;

	device_remove_file(dev, &dev_attr_online);
	device_remove_groups(dev, dev->groups);

	if (type)
		device_remove_groups(dev, type->groups);

	if (class)
		device_remove_groups(dev, class->dev_groups);
}

static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
			char *buf)
{
	return print_dev_t(buf, dev->devt);
}
static DEVICE_ATTR_RO(dev);

/* /sys/devices/ */
struct kset *devices_kset;

/**
 * devices_kset_move_before - Move device in the devices_kset's list.
 * @deva: Device to move.
 * @devb: Device @deva should come before.
 */
static void devices_kset_move_before(struct device *deva, struct device *devb)
{
	if (!devices_kset)
		return;
	pr_debug("devices_kset: Moving %s before %s\n",
		 dev_name(deva), dev_name(devb));
	spin_lock(&devices_kset->list_lock);
	list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
	spin_unlock(&devices_kset->list_lock);
}

/**
 * devices_kset_move_after - Move device in the devices_kset's list.
 * @deva: Device to move
 * @devb: Device @deva should come after.
 */
static void devices_kset_move_after(struct device *deva, struct device *devb)
{
	if (!devices_kset)
		return;
	pr_debug("devices_kset: Moving %s after %s\n",
		 dev_name(deva), dev_name(devb));
	spin_lock(&devices_kset->list_lock);
	list_move(&deva->kobj.entry, &devb->kobj.entry);
	spin_unlock(&devices_kset->list_lock);
}

/**
 * devices_kset_move_last - move the device to the end of devices_kset's list.
 * @dev: device to move
 */
void devices_kset_move_last(struct device *dev)
{
	if (!devices_kset)
		return;
	pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
	spin_lock(&devices_kset->list_lock);
	list_move_tail(&dev->kobj.entry, &devices_kset->list);
	spin_unlock(&devices_kset->list_lock);
}

/**
 * device_create_file - create sysfs attribute file for device.
 * @dev: device.
 * @attr: device attribute descriptor.
 */
int device_create_file(struct device *dev,
		       const struct device_attribute *attr)
{
	int error = 0;

	if (dev) {
		WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
			"Attribute %s: write permission without 'store'\n",
			attr->attr.name);
		WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
			"Attribute %s: read permission without 'show'\n",
			attr->attr.name);
		error = sysfs_create_file(&dev->kobj, &attr->attr);
	}

	return error;
}
EXPORT_SYMBOL_GPL(device_create_file);

/**
 * device_remove_file - remove sysfs attribute file.
 * @dev: device.
 * @attr: device attribute descriptor.
 */
void device_remove_file(struct device *dev,
			const struct device_attribute *attr)
{
	if (dev)
		sysfs_remove_file(&dev->kobj, &attr->attr);
}
EXPORT_SYMBOL_GPL(device_remove_file);

/**
 * device_remove_file_self - remove sysfs attribute file from its own method.
 * @dev: device.
 * @attr: device attribute descriptor.
 *
 * See kernfs_remove_self() for details.
 */
bool device_remove_file_self(struct device *dev,
			     const struct device_attribute *attr)
{
	if (dev)
		return sysfs_remove_file_self(&dev->kobj, &attr->attr);
	else
		return false;
}
EXPORT_SYMBOL_GPL(device_remove_file_self);

/**
 * device_create_bin_file - create sysfs binary attribute file for device.
 * @dev: device.
 * @attr: device binary attribute descriptor.
 */
int device_create_bin_file(struct device *dev,
			   const struct bin_attribute *attr)
{
	int error = -EINVAL;
	if (dev)
		error = sysfs_create_bin_file(&dev->kobj, attr);
	return error;
}
EXPORT_SYMBOL_GPL(device_create_bin_file);

/**
 * device_remove_bin_file - remove sysfs binary attribute file
 * @dev: device.
 * @attr: device binary attribute descriptor.
 */
void device_remove_bin_file(struct device *dev,
			    const struct bin_attribute *attr)
{
	if (dev)
		sysfs_remove_bin_file(&dev->kobj, attr);
}
EXPORT_SYMBOL_GPL(device_remove_bin_file);

static void klist_children_get(struct klist_node *n)
{
	struct device_private *p = to_device_private_parent(n);
	struct device *dev = p->device;

	get_device(dev);
}

static void klist_children_put(struct klist_node *n)
{
	struct device_private *p = to_device_private_parent(n);
	struct device *dev = p->device;

	put_device(dev);
}

/**
 * device_initialize - init device structure.
 * @dev: device.
 *
 * This prepares the device for use by other layers by initializing
 * its fields.
 * It is the first half of device_register(), if called by
 * that function, though it can also be called separately, so one
 * may use @dev's fields. In particular, get_device()/put_device()
 * may be used for reference counting of @dev after calling this
 * function.
 *
 * All fields in @dev must be initialized by the caller to 0, except
 * for those explicitly set to some other value.  The simplest
 * approach is to use kzalloc() to allocate the structure containing
 * @dev.
 *
 * NOTE: Use put_device() to give up your reference instead of freeing
 * @dev directly once you have called this function.
 */
void device_initialize(struct device *dev)
{
	dev->kobj.kset = devices_kset;
	kobject_init(&dev->kobj, &device_ktype);
	INIT_LIST_HEAD(&dev->dma_pools);
	mutex_init(&dev->mutex);
#ifdef CONFIG_PROVE_LOCKING
	mutex_init(&dev->lockdep_mutex);
#endif
	lockdep_set_novalidate_class(&dev->mutex);
	spin_lock_init(&dev->devres_lock);
	INIT_LIST_HEAD(&dev->devres_head);
	device_pm_init(dev);
	set_dev_node(dev, -1);
#ifdef CONFIG_GENERIC_MSI_IRQ
	INIT_LIST_HEAD(&dev->msi_list);
#endif
	INIT_LIST_HEAD(&dev->links.consumers);
	INIT_LIST_HEAD(&dev->links.suppliers);
	INIT_LIST_HEAD(&dev->links.needs_suppliers);
	INIT_LIST_HEAD(&dev->links.defer_sync);
	dev->links.status = DL_DEV_NO_DRIVER;
}
EXPORT_SYMBOL_GPL(device_initialize);

struct kobject *virtual_device_parent(struct device *dev)
{
	static struct kobject *virtual_dir = NULL;

	if (!virtual_dir)
		virtual_dir = kobject_create_and_add("virtual",
						     &devices_kset->kobj);

	return virtual_dir;
}

struct class_dir {
	struct kobject kobj;
	struct class *class;
};

#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)

static void class_dir_release(struct kobject *kobj)
{
	struct class_dir *dir = to_class_dir(kobj);
	kfree(dir);
}

static const
struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
{
	struct class_dir *dir = to_class_dir(kobj);
	return dir->class->ns_type;
}

static struct kobj_type class_dir_ktype = {
	.release	= class_dir_release,
	.sysfs_ops	= &kobj_sysfs_ops,
	.child_ns_type	= class_dir_child_ns_type
};

static struct kobject *
class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
{
	struct class_dir *dir;
	int retval;

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

	dir->class = class;
	kobject_init(&dir->kobj, &class_dir_ktype);

	dir->kobj.kset = &class->p->glue_dirs;

	retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
	if (retval < 0) {
		kobject_put(&dir->kobj);
		return ERR_PTR(retval);
	}
	return &dir->kobj;
}

static DEFINE_MUTEX(gdp_mutex);

static struct kobject *get_device_parent(struct device *dev,
					 struct device *parent)
{
	if (dev->class) {
		struct kobject *kobj = NULL;
		struct kobject *parent_kobj;
		struct kobject *k;

#ifdef CONFIG_BLOCK
		/* block disks show up in /sys/block */
		if (sysfs_deprecated && dev->class == &block_class) {
			if (parent && parent->class == &block_class)
				return &parent->kobj;
			return &block_class.p->subsys.kobj;
		}
#endif

		/*
		 * If we have no parent, we live in "virtual".
		 * Class-devices with a non class-device as parent, live
		 * in a "glue" directory to prevent namespace collisions.
		 */
		if (parent == NULL)
			parent_kobj = virtual_device_parent(dev);
		else if (parent->class && !dev->class->ns_type)
			return &parent->kobj;
		else
			parent_kobj = &parent->kobj;

		mutex_lock(&gdp_mutex);

		/* find our class-directory at the parent and reference it */
		spin_lock(&dev->class->p->glue_dirs.list_lock);
		list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
			if (k->parent == parent_kobj) {
				kobj = kobject_get(k);
				break;
			}
		spin_unlock(&dev->class->p->glue_dirs.list_lock);
		if (kobj) {
			mutex_unlock(&gdp_mutex);
			return kobj;
		}

		/* or create a new class-directory at the parent device */
		k = class_dir_create_and_add(dev->class, parent_kobj);
		/* do not emit an uevent for this simple "glue" directory */
		mutex_unlock(&gdp_mutex);
		return k;
	}

	/* subsystems can specify a default root directory for their devices */
	if (!parent && dev->bus && dev->bus->dev_root)
		return &dev->bus->dev_root->kobj;

	if (parent)
		return &parent->kobj;
	return NULL;
}

static inline bool live_in_glue_dir(struct kobject *kobj,
				    struct device *dev)
{
	if (!kobj || !dev->class ||
	    kobj->kset != &dev->class->p->glue_dirs)
		return false;
	return true;
}

static inline struct kobject *get_glue_dir(struct device *dev)
{
	return dev->kobj.parent;
}

/*
 * make sure cleaning up dir as the last step, we need to make
 * sure .release handler of kobject is run with holding the
 * global lock
 */
static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
{
	unsigned int ref;

	/* see if we live in a "glue" directory */
	if (!live_in_glue_dir(glue_dir, dev))
		return;

	mutex_lock(&gdp_mutex);
	/**
	 * There is a race condition between removing glue directory
	 * and adding a new device under the glue directory.
	 *
	 * CPU1:                                         CPU2:
	 *
	 * device_add()
	 *   get_device_parent()
	 *     class_dir_create_and_add()
	 *       kobject_add_internal()
	 *         create_dir()    // create glue_dir
	 *
	 *                                               device_add()
	 *                                                 get_device_parent()
	 *                                                   kobject_get() // get glue_dir
	 *
	 * device_del()
	 *   cleanup_glue_dir()
	 *     kobject_del(glue_dir)
	 *
	 *                                               kobject_add()
	 *                                                 kobject_add_internal()
	 *                                                   create_dir() // in glue_dir
	 *                                                     sysfs_create_dir_ns()
	 *                                                       kernfs_create_dir_ns(sd)
	 *
	 *       sysfs_remove_dir() // glue_dir->sd=NULL
	 *       sysfs_put()        // free glue_dir->sd
	 *
	 *                                                         // sd is freed
	 *                                                         kernfs_new_node(sd)
	 *                                                           kernfs_get(glue_dir)
	 *                                                           kernfs_add_one()
	 *                                                           kernfs_put()
	 *
	 * Before CPU1 remove last child device under glue dir, if CPU2 add
	 * a new device under glue dir, the glue_dir kobject reference count
	 * will be increase to 2 in kobject_get(k). And CPU2 has been called
	 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
	 * and sysfs_put(). This result in glue_dir->sd is freed.
	 *
	 * Then the CPU2 will see a stale "empty" but still potentially used
	 * glue dir around in kernfs_new_node().
	 *
	 * In order to avoid this happening, we also should make sure that
	 * kernfs_node for glue_dir is released in CPU1 only when refcount
	 * for glue_dir kobj is 1.
	 */
	ref = kref_read(&glue_dir->kref);
	if (!kobject_has_children(glue_dir) && !--ref)
		kobject_del(glue_dir);
	kobject_put(glue_dir);
	mutex_unlock(&gdp_mutex);
}

static int device_add_class_symlinks(struct device *dev)
{
	struct device_node *of_node = dev_of_node(dev);
	int error;

	if (of_node) {
		error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
		if (error)
			dev_warn(dev, "Error %d creating of_node link\n",error);
		/* An error here doesn't warrant bringing down the device */
	}

	if (!dev->class)
		return 0;

	error = sysfs_create_link(&dev->kobj,
				  &dev->class->p->subsys.kobj,
				  "subsystem");
	if (error)
		goto out_devnode;

	if (dev->parent && device_is_not_partition(dev)) {
		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
					  "device");
		if (error)
			goto out_subsys;
	}

#ifdef CONFIG_BLOCK
	/* /sys/block has directories and does not need symlinks */
	if (sysfs_deprecated && dev->class == &block_class)
		return 0;
#endif

	/* link in the class directory pointing to the device */
	error = sysfs_create_link(&dev->class->p->subsys.kobj,
				  &dev->kobj, dev_name(dev));
	if (error)
		goto out_device;

	return 0;

out_device:
	sysfs_remove_link(&dev->kobj, "device");

out_subsys:
	sysfs_remove_link(&dev->kobj, "subsystem");
out_devnode:
	sysfs_remove_link(&dev->kobj, "of_node");
	return error;
}

static void device_remove_class_symlinks(struct device *dev)
{
	if (dev_of_node(dev))
		sysfs_remove_link(&dev->kobj, "of_node");

	if (!dev->class)
		return;

	if (dev->parent && device_is_not_partition(dev))
		sysfs_remove_link(&dev->kobj, "device");
	sysfs_remove_link(&dev->kobj, "subsystem");
#ifdef CONFIG_BLOCK
	if (sysfs_deprecated && dev->class == &block_class)
		return;
#endif
	sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
}

/**
 * dev_set_name - set a device name
 * @dev: device
 * @fmt: format string for the device's name
 */
int dev_set_name(struct device *dev, const char *fmt, ...)
{
	va_list vargs;
	int err;

	va_start(vargs, fmt);
	err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
	va_end(vargs);
	return err;
}
EXPORT_SYMBOL_GPL(dev_set_name);

/**
 * device_to_dev_kobj - select a /sys/dev/ directory for the device
 * @dev: device
 *
 * By default we select char/ for new entries.  Setting class->dev_obj
 * to NULL prevents an entry from being created.  class->dev_kobj must
 * be set (or cleared) before any devices are registered to the class
 * otherwise device_create_sys_dev_entry() and
 * device_remove_sys_dev_entry() will disagree about the presence of
 * the link.
 */
static struct kobject *device_to_dev_kobj(struct device *dev)
{
	struct kobject *kobj;

	if (dev->class)
		kobj = dev->class->dev_kobj;
	else
		kobj = sysfs_dev_char_kobj;

	return kobj;
}

static int device_create_sys_dev_entry(struct device *dev)
{
	struct kobject *kobj = device_to_dev_kobj(dev);
	int error = 0;
	char devt_str[15];

	if (kobj) {
		format_dev_t(devt_str, dev->devt);
		error = sysfs_create_link(kobj, &dev->kobj, devt_str);
	}

	return error;
}

static void device_remove_sys_dev_entry(struct device *dev)
{
	struct kobject *kobj = device_to_dev_kobj(dev);
	char devt_str[15];

	if (kobj) {
		format_dev_t(devt_str, dev->devt);
		sysfs_remove_link(kobj, devt_str);
	}
}

static int device_private_init(struct device *dev)
{
	dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
	if (!dev->p)
		return -ENOMEM;
	dev->p->device = dev;
	klist_init(&dev->p->klist_children, klist_children_get,
		   klist_children_put);
	INIT_LIST_HEAD(&dev->p->deferred_probe);
	return 0;
}

static u32 fw_devlink_flags;
static int __init fw_devlink_setup(char *arg)
{
	if (!arg)
		return -EINVAL;

	if (strcmp(arg, "off") == 0) {
		fw_devlink_flags = 0;
	} else if (strcmp(arg, "permissive") == 0) {
		fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY;
	} else if (strcmp(arg, "on") == 0) {
		fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER;
	} else if (strcmp(arg, "rpm") == 0) {
		fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER |
				   DL_FLAG_PM_RUNTIME;
	}
	return 0;
}
early_param("fw_devlink", fw_devlink_setup);

u32 fw_devlink_get_flags(void)
{
	return fw_devlink_flags;
}

/**
 * device_add - add device to device hierarchy.
 * @dev: device.
 *
 * This is part 2 of device_register(), though may be called
 * separately _iff_ device_initialize() has been called separately.
 *
 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
 * to the global and sibling lists for the device, then
 * adds it to the other relevant subsystems of the driver model.
 *
 * Do not call this routine or device_register() more than once for
 * any device structure.  The driver model core is not designed to work
 * with devices that get unregistered and then spring back to life.
 * (Among other things, it's very hard to guarantee that all references
 * to the previous incarnation of @dev have been dropped.)  Allocate
 * and register a fresh new struct device instead.
 *
 * NOTE: _Never_ directly free @dev after calling this function, even
 * if it returned an error! Always use put_device() to give up your
 * reference instead.
 *
 * Rule of thumb is: if device_add() succeeds, you should call
 * device_del() when you want to get rid of it. If device_add() has
 * *not* succeeded, use *only* put_device() to drop the reference
 * count.
 */
int device_add(struct device *dev)
{
	struct device *parent;
	struct kobject *kobj;
	struct class_interface *class_intf;
	int error = -EINVAL, fw_ret;
	struct kobject *glue_dir = NULL;
	bool is_fwnode_dev = false;

	dev = get_device(dev);
	if (!dev)
		goto done;

	if (!dev->p) {
		error = device_private_init(dev);
		if (error)
			goto done;
	}

	/*
	 * for statically allocated devices, which should all be converted
	 * some day, we need to initialize the name. We prevent reading back
	 * the name, and force the use of dev_name()
	 */
	if (dev->init_name) {
		dev_set_name(dev, "%s", dev->init_name);
		dev->init_name = NULL;
	}

	/* subsystems can specify simple device enumeration */
	if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
		dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);

	if (!dev_name(dev)) {
		error = -EINVAL;
		goto name_error;
	}

	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);

	parent = get_device(dev->parent);
	kobj = get_device_parent(dev, parent);
	if (IS_ERR(kobj)) {
		error = PTR_ERR(kobj);
		goto parent_error;
	}
	if (kobj)
		dev->kobj.parent = kobj;

	/* use parent numa_node */
	if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
		set_dev_node(dev, dev_to_node(parent));

	/* first, register with generic layer. */
	/* we require the name to be set before, and pass NULL */
	error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
	if (error) {
		glue_dir = get_glue_dir(dev);
		goto Error;
	}

	/* notify platform of device entry */
	error = device_platform_notify(dev, KOBJ_ADD);
	if (error)
		goto platform_error;

	error = device_create_file(dev, &dev_attr_uevent);
	if (error)
		goto attrError;

	error = device_add_class_symlinks(dev);
	if (error)
		goto SymlinkError;
	error = device_add_attrs(dev);
	if (error)
		goto AttrsError;
	error = bus_add_device(dev);
	if (error)
		goto BusError;
	error = dpm_sysfs_add(dev);
	if (error)
		goto DPMError;
	device_pm_add(dev);

	if (MAJOR(dev->devt)) {
		error = device_create_file(dev, &dev_attr_dev);
		if (error)
			goto DevAttrError;

		error = device_create_sys_dev_entry(dev);
		if (error)
			goto SysEntryError;

		devtmpfs_create_node(dev);
	}

	/* Notify clients of device addition.  This call must come
	 * after dpm_sysfs_add() and before kobject_uevent().
	 */
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
					     BUS_NOTIFY_ADD_DEVICE, dev);

	kobject_uevent(&dev->kobj, KOBJ_ADD);

	if (dev->fwnode && !dev->fwnode->dev) {
		dev->fwnode->dev = dev;
		is_fwnode_dev = true;
	}

	/*
	 * Check if any of the other devices (consumers) have been waiting for
	 * this device (supplier) to be added so that they can create a device
	 * link to it.
	 *
	 * This needs to happen after device_pm_add() because device_link_add()
	 * requires the supplier be registered before it's called.
	 *
	 * But this also needs to happe before bus_probe_device() to make sure
	 * waiting consumers can link to it before the driver is bound to the
	 * device and the driver sync_state callback is called for this device.
	 */
	device_link_add_missing_supplier_links();

	if (fw_devlink_flags && is_fwnode_dev &&
	    fwnode_has_op(dev->fwnode, add_links)) {
		fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
		if (fw_ret == -ENODEV)
			device_link_wait_for_mandatory_supplier(dev);
		else if (fw_ret)
			device_link_wait_for_optional_supplier(dev);
	}

	bus_probe_device(dev);
	if (parent)
		klist_add_tail(&dev->p->knode_parent,
			       &parent->p->klist_children);

	if (dev->class) {
		mutex_lock(&dev->class->p->mutex);
		/* tie the class to the device */
		klist_add_tail(&dev->p->knode_class,
			       &dev->class->p->klist_devices);

		/* notify any interfaces that the device is here */
		list_for_each_entry(class_intf,
				    &dev->class->p->interfaces, node)
			if (class_intf->add_dev)
				class_intf->add_dev(dev, class_intf);
		mutex_unlock(&dev->class->p->mutex);
	}
done:
	put_device(dev);
	return error;
 SysEntryError:
	if (MAJOR(dev->devt))
		device_remove_file(dev, &dev_attr_dev);
 DevAttrError:
	device_pm_remove(dev);
	dpm_sysfs_remove(dev);
 DPMError:
	bus_remove_device(dev);
 BusError:
	device_remove_attrs(dev);
 AttrsError:
	device_remove_class_symlinks(dev);
 SymlinkError:
	device_remove_file(dev, &dev_attr_uevent);
 attrError:
	device_platform_notify(dev, KOBJ_REMOVE);
platform_error:
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
	glue_dir = get_glue_dir(dev);
	kobject_del(&dev->kobj);
 Error:
	cleanup_glue_dir(dev, glue_dir);
parent_error:
	put_device(parent);
name_error:
	kfree(dev->p);
	dev->p = NULL;
	goto done;
}
EXPORT_SYMBOL_GPL(device_add);

/**
 * device_register - register a device with the system.
 * @dev: pointer to the device structure
 *
 * This happens in two clean steps - initialize the device
 * and add it to the system. The two steps can be called
 * separately, but this is the easiest and most common.
 * I.e. you should only call the two helpers separately if
 * have a clearly defined need to use and refcount the device
 * before it is added to the hierarchy.
 *
 * For more information, see the kerneldoc for device_initialize()
 * and device_add().
 *
 * NOTE: _Never_ directly free @dev after calling this function, even
 * if it returned an error! Always use put_device() to give up the
 * reference initialized in this function instead.
 */
int device_register(struct device *dev)
{
	device_initialize(dev);
	return device_add(dev);
}
EXPORT_SYMBOL_GPL(device_register);

/**
 * get_device - increment reference count for device.
 * @dev: device.
 *
 * This simply forwards the call to kobject_get(), though
 * we do take care to provide for the case that we get a NULL
 * pointer passed in.
 */
struct device *get_device(struct device *dev)
{
	return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
}
EXPORT_SYMBOL_GPL(get_device);

/**
 * put_device - decrement reference count.
 * @dev: device in question.
 */
void put_device(struct device *dev)
{
	/* might_sleep(); */
	if (dev)
		kobject_put(&dev->kobj);
}
EXPORT_SYMBOL_GPL(put_device);

bool kill_device(struct device *dev)
{
	/*
	 * Require the device lock and set the "dead" flag to guarantee that
	 * the update behavior is consistent with the other bitfields near
	 * it and that we cannot have an asynchronous probe routine trying
	 * to run while we are tearing out the bus/class/sysfs from
	 * underneath the device.
	 */
	lockdep_assert_held(&dev->mutex);

	if (dev->p->dead)
		return false;
	dev->p->dead = true;
	return true;
}
EXPORT_SYMBOL_GPL(kill_device);

/**
 * device_del - delete device from system.
 * @dev: device.
 *
 * This is the first part of the device unregistration
 * sequence. This removes the device from the lists we control
 * from here, has it removed from the other driver model
 * subsystems it was added to in device_add(), and removes it
 * from the kobject hierarchy.
 *
 * NOTE: this should be called manually _iff_ device_add() was
 * also called manually.
 */
void device_del(struct device *dev)
{
	struct device *parent = dev->parent;
	struct kobject *glue_dir = NULL;
	struct class_interface *class_intf;

	device_lock(dev);
	kill_device(dev);
	device_unlock(dev);

	if (dev->fwnode && dev->fwnode->dev == dev)
		dev->fwnode->dev = NULL;

	/* Notify clients of device removal.  This call must come
	 * before dpm_sysfs_remove().
	 */
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);

	dpm_sysfs_remove(dev);
	if (parent)
		klist_del(&dev->p->knode_parent);
	if (MAJOR(dev->devt)) {
		devtmpfs_delete_node(dev);
		device_remove_sys_dev_entry(dev);
		device_remove_file(dev, &dev_attr_dev);
	}
	if (dev->class) {
		device_remove_class_symlinks(dev);

		mutex_lock(&dev->class->p->mutex);
		/* notify any interfaces that the device is now gone */
		list_for_each_entry(class_intf,
				    &dev->class->p->interfaces, node)
			if (class_intf->remove_dev)
				class_intf->remove_dev(dev, class_intf);
		/* remove the device from the class list */
		klist_del(&dev->p->knode_class);
		mutex_unlock(&dev->class->p->mutex);
	}
	device_remove_file(dev, &dev_attr_uevent);
	device_remove_attrs(dev);
	bus_remove_device(dev);
	device_pm_remove(dev);
	driver_deferred_probe_del(dev);
	device_platform_notify(dev, KOBJ_REMOVE);
	device_remove_properties(dev);
	device_links_purge(dev);

	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
					     BUS_NOTIFY_REMOVED_DEVICE, dev);
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
	glue_dir = get_glue_dir(dev);
	kobject_del(&dev->kobj);
	cleanup_glue_dir(dev, glue_dir);
	put_device(parent);
}
EXPORT_SYMBOL_GPL(device_del);

/**
 * device_unregister - unregister device from system.
 * @dev: device going away.
 *
 * We do this in two parts, like we do device_register(). First,
 * we remove it from all the subsystems with device_del(), then
 * we decrement the reference count via put_device(). If that
 * is the final reference count, the device will be cleaned up
 * via device_release() above. Otherwise, the structure will
 * stick around until the final reference to the device is dropped.
 */
void device_unregister(struct device *dev)
{
	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
	device_del(dev);
	put_device(dev);
}
EXPORT_SYMBOL_GPL(device_unregister);

static struct device *prev_device(struct klist_iter *i)
{
	struct klist_node *n = klist_prev(i);
	struct device *dev = NULL;
	struct device_private *p;

	if (n) {
		p = to_device_private_parent(n);
		dev = p->device;
	}
	return dev;
}

static struct device *next_device(struct klist_iter *i)
{
	struct klist_node *n = klist_next(i);
	struct device *dev = NULL;
	struct device_private *p;

	if (n) {
		p = to_device_private_parent(n);
		dev = p->device;
	}
	return dev;
}

/**
 * device_get_devnode - path of device node file
 * @dev: device
 * @mode: returned file access mode
 * @uid: returned file owner
 * @gid: returned file group
 * @tmp: possibly allocated string
 *
 * Return the relative path of a possible device node.
 * Non-default names may need to allocate a memory to compose
 * a name. This memory is returned in tmp and needs to be
 * freed by the caller.
 */
const char *device_get_devnode(struct device *dev,
			       umode_t *mode, kuid_t *uid, kgid_t *gid,
			       const char **tmp)
{
	char *s;

	*tmp = NULL;

	/* the device type may provide a specific name */
	if (dev->type && dev->type->devnode)
		*tmp = dev->type->devnode(dev, mode, uid, gid);
	if (*tmp)
		return *tmp;

	/* the class may provide a specific name */
	if (dev->class && dev->class->devnode)
		*tmp = dev->class->devnode(dev, mode);
	if (*tmp)
		return *tmp;

	/* return name without allocation, tmp == NULL */
	if (strchr(dev_name(dev), '!') == NULL)
		return dev_name(dev);

	/* replace '!' in the name with '/' */
	s = kstrdup(dev_name(dev), GFP_KERNEL);
	if (!s)
		return NULL;
	strreplace(s, '!', '/');
	return *tmp = s;
}

/**
 * device_for_each_child - device child iterator.
 * @parent: parent struct device.
 * @fn: function to be called for each device.
 * @data: data for the callback.
 *
 * Iterate over @parent's child devices, and call @fn for each,
 * passing it @data.
 *
 * We check the return of @fn each time. If it returns anything
 * other than 0, we break out and return that value.
 */
int device_for_each_child(struct device *parent, void *data,
			  int (*fn)(struct device *dev, void *data))
{
	struct klist_iter i;
	struct device *child;
	int error = 0;

	if (!parent->p)
		return 0;

	klist_iter_init(&parent->p->klist_children, &i);
	while (!error && (child = next_device(&i)))
		error = fn(child, data);
	klist_iter_exit(&i);
	return error;
}
EXPORT_SYMBOL_GPL(device_for_each_child);

/**
 * device_for_each_child_reverse - device child iterator in reversed order.
 * @parent: parent struct device.
 * @fn: function to be called for each device.
 * @data: data for the callback.
 *
 * Iterate over @parent's child devices, and call @fn for each,
 * passing it @data.
 *
 * We check the return of @fn each time. If it returns anything
 * other than 0, we break out and return that value.
 */
int device_for_each_child_reverse(struct device *parent, void *data,
				  int (*fn)(struct device *dev, void *data))
{
	struct klist_iter i;
	struct device *child;
	int error = 0;

	if (!parent->p)
		return 0;

	klist_iter_init(&parent->p->klist_children, &i);
	while ((child = prev_device(&i)) && !error)
		error = fn(child, data);
	klist_iter_exit(&i);
	return error;
}
EXPORT_SYMBOL_GPL(device_for_each_child_reverse);

/**
 * device_find_child - device iterator for locating a particular device.
 * @parent: parent struct device
 * @match: Callback function to check device
 * @data: Data to pass to match function
 *
 * This is similar to the device_for_each_child() function above, but it
 * returns a reference to a device that is 'found' for later use, as
 * determined by the @match callback.
 *
 * The callback should return 0 if the device doesn't match and non-zero
 * if it does.  If the callback returns non-zero and a reference to the
 * current device can be obtained, this function will return to the caller
 * and not iterate over any more devices.
 *
 * NOTE: you will need to drop the reference with put_device() after use.
 */
struct device *device_find_child(struct device *parent, void *data,
				 int (*match)(struct device *dev, void *data))
{
	struct klist_iter i;
	struct device *child;

	if (!parent)
		return NULL;

	klist_iter_init(&parent->p->klist_children, &i);
	while ((child = next_device(&i)))
		if (match(child, data) && get_device(child))
			break;
	klist_iter_exit(&i);
	return child;
}
EXPORT_SYMBOL_GPL(device_find_child);

/**
 * device_find_child_by_name - device iterator for locating a child device.
 * @parent: parent struct device
 * @name: name of the child device
 *
 * This is similar to the device_find_child() function above, but it
 * returns a reference to a device that has the name @name.
 *
 * NOTE: you will need to drop the reference with put_device() after use.
 */
struct device *device_find_child_by_name(struct device *parent,
					 const char *name)
{
	struct klist_iter i;
	struct device *child;

	if (!parent)
		return NULL;

	klist_iter_init(&parent->p->klist_children, &i);
	while ((child = next_device(&i)))
		if (!strcmp(dev_name(child), name) && get_device(child))
			break;
	klist_iter_exit(&i);
	return child;
}
EXPORT_SYMBOL_GPL(device_find_child_by_name);

int __init devices_init(void)
{
	devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
	if (!devices_kset)
		return -ENOMEM;
	dev_kobj = kobject_create_and_add("dev", NULL);
	if (!dev_kobj)
		goto dev_kobj_err;
	sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
	if (!sysfs_dev_block_kobj)
		goto block_kobj_err;
	sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
	if (!sysfs_dev_char_kobj)
		goto char_kobj_err;

	return 0;

 char_kobj_err:
	kobject_put(sysfs_dev_block_kobj);
 block_kobj_err:
	kobject_put(dev_kobj);
 dev_kobj_err:
	kset_unregister(devices_kset);
	return -ENOMEM;
}

static int device_check_offline(struct device *dev, void *not_used)
{
	int ret;

	ret = device_for_each_child(dev, NULL, device_check_offline);
	if (ret)
		return ret;

	return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
}

/**
 * device_offline - Prepare the device for hot-removal.
 * @dev: Device to be put offline.
 *
 * Execute the device bus type's .offline() callback, if present, to prepare
 * the device for a subsequent hot-removal.  If that succeeds, the device must
 * not be used until either it is removed or its bus type's .online() callback
 * is executed.
 *
 * Call under device_hotplug_lock.
 */
int device_offline(struct device *dev)
{
	int ret;

	if (dev->offline_disabled)
		return -EPERM;

	ret = device_for_each_child(dev, NULL, device_check_offline);
	if (ret)
		return ret;

	device_lock(dev);
	if (device_supports_offline(dev)) {
		if (dev->offline) {
			ret = 1;
		} else {
			ret = dev->bus->offline(dev);
			if (!ret) {
				kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
				dev->offline = true;
			}
		}
	}
	device_unlock(dev);

	return ret;
}

/**
 * device_online - Put the device back online after successful device_offline().
 * @dev: Device to be put back online.
 *
 * If device_offline() has been successfully executed for @dev, but the device
 * has not been removed subsequently, execute its bus type's .online() callback
 * to indicate that the device can be used again.
 *
 * Call under device_hotplug_lock.
 */
int device_online(struct device *dev)
{
	int ret = 0;

	device_lock(dev);
	if (device_supports_offline(dev)) {
		if (dev->offline) {
			ret = dev->bus->online(dev);
			if (!ret) {
				kobject_uevent(&dev->kobj, KOBJ_ONLINE);
				dev->offline = false;
			}
		} else {
			ret = 1;
		}
	}
	device_unlock(dev);

	return ret;
}

struct root_device {
	struct device dev;
	struct module *owner;
};

static inline struct root_device *to_root_device(struct device *d)
{
	return container_of(d, struct root_device, dev);
}

static void root_device_release(struct device *dev)
{
	kfree(to_root_device(dev));
}

/**
 * __root_device_register - allocate and register a root device
 * @name: root device name
 * @owner: owner module of the root device, usually THIS_MODULE
 *
 * This function allocates a root device and registers it
 * using device_register(). In order to free the returned
 * device, use root_device_unregister().
 *
 * Root devices are dummy devices which allow other devices
 * to be grouped under /sys/devices. Use this function to
 * allocate a root device and then use it as the parent of
 * any device which should appear under /sys/devices/{name}
 *
 * The /sys/devices/{name} directory will also contain a
 * 'module' symlink which points to the @owner directory
 * in sysfs.
 *
 * Returns &struct device pointer on success, or ERR_PTR() on error.
 *
 * Note: You probably want to use root_device_register().
 */
struct device *__root_device_register(const char *name, struct module *owner)
{
	struct root_device *root;
	int err = -ENOMEM;

	root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
	if (!root)
		return ERR_PTR(err);

	err = dev_set_name(&root->dev, "%s", name);
	if (err) {
		kfree(root);
		return ERR_PTR(err);
	}

	root->dev.release = root_device_release;

	err = device_register(&root->dev);
	if (err) {
		put_device(&root->dev);
		return ERR_PTR(err);
	}

#ifdef CONFIG_MODULES	/* gotta find a "cleaner" way to do this */
	if (owner) {
		struct module_kobject *mk = &owner->mkobj;

		err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
		if (err) {
			device_unregister(&root->dev);
			return ERR_PTR(err);
		}
		root->owner = owner;
	}
#endif

	return &root->dev;
}
EXPORT_SYMBOL_GPL(__root_device_register);

/**
 * root_device_unregister - unregister and free a root device
 * @dev: device going away
 *
 * This function unregisters and cleans up a device that was created by
 * root_device_register().
 */
void root_device_unregister(struct device *dev)
{
	struct root_device *root = to_root_device(dev);

	if (root->owner)
		sysfs_remove_link(&root->dev.kobj, "module");

	device_unregister(dev);
}
EXPORT_SYMBOL_GPL(root_device_unregister);


static void device_create_release(struct device *dev)
{
	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
	kfree(dev);
}

static __printf(6, 0) struct device *
device_create_groups_vargs(struct class *class, struct device *parent,
			   dev_t devt, void *drvdata,
			   const struct attribute_group **groups,
			   const char *fmt, va_list args)
{
	struct device *dev = NULL;
	int retval = -ENODEV;

	if (class == NULL || IS_ERR(class))
		goto error;

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev) {
		retval = -ENOMEM;
		goto error;
	}

	device_initialize(dev);
	dev->devt = devt;
	dev->class = class;
	dev->parent = parent;
	dev->groups = groups;
	dev->release = device_create_release;
	dev_set_drvdata(dev, drvdata);

	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
	if (retval)
		goto error;

	retval = device_add(dev);
	if (retval)
		goto error;

	return dev;

error:
	put_device(dev);
	return ERR_PTR(retval);
}

/**
 * device_create_vargs - creates a device and registers it with sysfs
 * @class: pointer to the struct class that this device should be registered to
 * @parent: pointer to the parent struct device of this new device, if any
 * @devt: the dev_t for the char device to be added
 * @drvdata: the data to be added to the device for callbacks
 * @fmt: string for the device's name
 * @args: va_list for the device's name
 *
 * This function can be used by char device classes.  A struct device
 * will be created in sysfs, registered to the specified class.
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
 * If a pointer to a parent struct device is passed in, the newly created
 * struct device will be a child of that device in sysfs.
 * The pointer to the struct device will be returned from the call.
 * Any further sysfs files that might be required can be created using this
 * pointer.
 *
 * Returns &struct device pointer on success, or ERR_PTR() on error.
 *
 * Note: the struct class passed to this function must have previously
 * been created with a call to class_create().
 */
struct device *device_create_vargs(struct class *class, struct device *parent,
				   dev_t devt, void *drvdata, const char *fmt,
				   va_list args)
{
	return device_create_groups_vargs(class, parent, devt, drvdata, NULL,
					  fmt, args);
}
EXPORT_SYMBOL_GPL(device_create_vargs);

/**
 * device_create - creates a device and registers it with sysfs
 * @class: pointer to the struct class that this device should be registered to
 * @parent: pointer to the parent struct device of this new device, if any
 * @devt: the dev_t for the char device to be added
 * @drvdata: the data to be added to the device for callbacks
 * @fmt: string for the device's name
 *
 * This function can be used by char device classes.  A struct device
 * will be created in sysfs, registered to the specified class.
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
 * If a pointer to a parent struct device is passed in, the newly created
 * struct device will be a child of that device in sysfs.
 * The pointer to the struct device will be returned from the call.
 * Any further sysfs files that might be required can be created using this
 * pointer.
 *
 * Returns &struct device pointer on success, or ERR_PTR() on error.
 *
 * Note: the struct class passed to this function must have previously
 * been created with a call to class_create().
 */
struct device *device_create(struct class *class, struct device *parent,
			     dev_t devt, void *drvdata, const char *fmt, ...)
{
	va_list vargs;
	struct device *dev;

	va_start(vargs, fmt);
	dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
	va_end(vargs);
	return dev;
}
EXPORT_SYMBOL_GPL(device_create);

/**
 * device_create_with_groups - creates a device and registers it with sysfs
 * @class: pointer to the struct class that this device should be registered to
 * @parent: pointer to the parent struct device of this new device, if any
 * @devt: the dev_t for the char device to be added
 * @drvdata: the data to be added to the device for callbacks
 * @groups: NULL-terminated list of attribute groups to be created
 * @fmt: string for the device's name
 *
 * This function can be used by char device classes.  A struct device
 * will be created in sysfs, registered to the specified class.
 * Additional attributes specified in the groups parameter will also
 * be created automatically.
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
 * If a pointer to a parent struct device is passed in, the newly created
 * struct device will be a child of that device in sysfs.
 * The pointer to the struct device will be returned from the call.
 * Any further sysfs files that might be required can be created using this
 * pointer.
 *
 * Returns &struct device pointer on success, or ERR_PTR() on error.
 *
 * Note: the struct class passed to this function must have previously
 * been created with a call to class_create().
 */
struct device *device_create_with_groups(struct class *class,
					 struct device *parent, dev_t devt,
					 void *drvdata,
					 const struct attribute_group **groups,
					 const char *fmt, ...)
{
	va_list vargs;
	struct device *dev;

	va_start(vargs, fmt);
	dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
					 fmt, vargs);
	va_end(vargs);
	return dev;
}
EXPORT_SYMBOL_GPL(device_create_with_groups);

/**
 * device_destroy - removes a device that was created with device_create()
 * @class: pointer to the struct class that this device was registered with
 * @devt: the dev_t of the device that was previously registered
 *
 * This call unregisters and cleans up a device that was created with a
 * call to device_create().
 */
void device_destroy(struct class *class, dev_t devt)
{
	struct device *dev;

	dev = class_find_device_by_devt(class, devt);
	if (dev) {
		put_device(dev);
		device_unregister(dev);
	}
}
EXPORT_SYMBOL_GPL(device_destroy);

/**
 * device_rename - renames a device
 * @dev: the pointer to the struct device to be renamed
 * @new_name: the new name of the device
 *
 * It is the responsibility of the caller to provide mutual
 * exclusion between two different calls of device_rename
 * on the same device to ensure that new_name is valid and
 * won't conflict with other devices.
 *
 * Note: Don't call this function.  Currently, the networking layer calls this
 * function, but that will change.  The following text from Kay Sievers offers
 * some insight:
 *
 * Renaming devices is racy at many levels, symlinks and other stuff are not
 * replaced atomically, and you get a "move" uevent, but it's not easy to
 * connect the event to the old and new device. Device nodes are not renamed at
 * all, there isn't even support for that in the kernel now.
 *
 * In the meantime, during renaming, your target name might be taken by another
 * driver, creating conflicts. Or the old name is taken directly after you
 * renamed it -- then you get events for the same DEVPATH, before you even see
 * the "move" event. It's just a mess, and nothing new should ever rely on
 * kernel device renaming. Besides that, it's not even implemented now for
 * other things than (driver-core wise very simple) network devices.
 *
 * We are currently about to change network renaming in udev to completely
 * disallow renaming of devices in the same namespace as the kernel uses,
 * because we can't solve the problems properly, that arise with swapping names
 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
 * be allowed to some other name than eth[0-9]*, for the aforementioned
 * reasons.
 *
 * Make up a "real" name in the driver before you register anything, or add
 * some other attributes for userspace to find the device, or use udev to add
 * symlinks -- but never rename kernel devices later, it's a complete mess. We
 * don't even want to get into that and try to implement the missing pieces in
 * the core. We really have other pieces to fix in the driver core mess. :)
 */
int device_rename(struct device *dev, const char *new_name)
{
	struct kobject *kobj = &dev->kobj;
	char *old_device_name = NULL;
	int error;

	dev = get_device(dev);
	if (!dev)
		return -EINVAL;

	dev_dbg(dev, "renaming to %s\n", new_name);

	old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
	if (!old_device_name) {
		error = -ENOMEM;
		goto out;
	}

	if (dev->class) {
		error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
					     kobj, old_device_name,
					     new_name, kobject_namespace(kobj));
		if (error)
			goto out;
	}

	error = kobject_rename(kobj, new_name);
	if (error)
		goto out;

out:
	put_device(dev);

	kfree(old_device_name);

	return error;
}
EXPORT_SYMBOL_GPL(device_rename);

static int device_move_class_links(struct device *dev,
				   struct device *old_parent,
				   struct device *new_parent)
{
	int error = 0;

	if (old_parent)
		sysfs_remove_link(&dev->kobj, "device");
	if (new_parent)
		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
					  "device");
	return error;
}

/**
 * device_move - moves a device to a new parent
 * @dev: the pointer to the struct device to be moved
 * @new_parent: the new parent of the device (can be NULL)
 * @dpm_order: how to reorder the dpm_list
 */
int device_move(struct device *dev, struct device *new_parent,
		enum dpm_order dpm_order)
{
	int error;
	struct device *old_parent;
	struct kobject *new_parent_kobj;

	dev = get_device(dev);
	if (!dev)
		return -EINVAL;

	device_pm_lock();
	new_parent = get_device(new_parent);
	new_parent_kobj = get_device_parent(dev, new_parent);
	if (IS_ERR(new_parent_kobj)) {
		error = PTR_ERR(new_parent_kobj);
		put_device(new_parent);
		goto out;
	}

	pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
		 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
	error = kobject_move(&dev->kobj, new_parent_kobj);
	if (error) {
		cleanup_glue_dir(dev, new_parent_kobj);
		put_device(new_parent);
		goto out;
	}
	old_parent = dev->parent;
	dev->parent = new_parent;
	if (old_parent)
		klist_remove(&dev->p->knode_parent);
	if (new_parent) {
		klist_add_tail(&dev->p->knode_parent,
			       &new_parent->p->klist_children);
		set_dev_node(dev, dev_to_node(new_parent));
	}

	if (dev->class) {
		error = device_move_class_links(dev, old_parent, new_parent);
		if (error) {
			/* We ignore errors on cleanup since we're hosed anyway... */
			device_move_class_links(dev, new_parent, old_parent);
			if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
				if (new_parent)
					klist_remove(&dev->p->knode_parent);
				dev->parent = old_parent;
				if (old_parent) {
					klist_add_tail(&dev->p->knode_parent,
						       &old_parent->p->klist_children);
					set_dev_node(dev, dev_to_node(old_parent));
				}
			}
			cleanup_glue_dir(dev, new_parent_kobj);
			put_device(new_parent);
			goto out;
		}
	}
	switch (dpm_order) {
	case DPM_ORDER_NONE:
		break;
	case DPM_ORDER_DEV_AFTER_PARENT:
		device_pm_move_after(dev, new_parent);
		devices_kset_move_after(dev, new_parent);
		break;
	case DPM_ORDER_PARENT_BEFORE_DEV:
		device_pm_move_before(new_parent, dev);
		devices_kset_move_before(new_parent, dev);
		break;
	case DPM_ORDER_DEV_LAST:
		device_pm_move_last(dev);
		devices_kset_move_last(dev);
		break;
	}

	put_device(old_parent);
out:
	device_pm_unlock();
	put_device(dev);
	return error;
}
EXPORT_SYMBOL_GPL(device_move);

static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
				     kgid_t kgid)
{
	struct kobject *kobj = &dev->kobj;
	struct class *class = dev->class;
	const struct device_type *type = dev->type;
	int error;

	if (class) {
		/*
		 * Change the device groups of the device class for @dev to
		 * @kuid/@kgid.
		 */
		error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
						  kgid);
		if (error)
			return error;
	}

	if (type) {
		/*
		 * Change the device groups of the device type for @dev to
		 * @kuid/@kgid.
		 */
		error = sysfs_groups_change_owner(kobj, type->groups, kuid,
						  kgid);
		if (error)
			return error;
	}

	/* Change the device groups of @dev to @kuid/@kgid. */
	error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
	if (error)
		return error;

	if (device_supports_offline(dev) && !dev->offline_disabled) {
		/* Change online device attributes of @dev to @kuid/@kgid. */
		error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
						kuid, kgid);
		if (error)
			return error;
	}

	return 0;
}

/**
 * device_change_owner - change the owner of an existing device.
 * @dev: device.
 * @kuid: new owner's kuid
 * @kgid: new owner's kgid
 *
 * This changes the owner of @dev and its corresponding sysfs entries to
 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
 * core.
 *
 * Returns 0 on success or error code on failure.
 */
int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
{
	int error;
	struct kobject *kobj = &dev->kobj;

	dev = get_device(dev);
	if (!dev)
		return -EINVAL;

	/*
	 * Change the kobject and the default attributes and groups of the
	 * ktype associated with it to @kuid/@kgid.
	 */
	error = sysfs_change_owner(kobj, kuid, kgid);
	if (error)
		goto out;

	/*
	 * Change the uevent file for @dev to the new owner. The uevent file
	 * was created in a separate step when @dev got added and we mirror
	 * that step here.
	 */
	error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
					kgid);
	if (error)
		goto out;

	/*
	 * Change the device groups, the device groups associated with the
	 * device class, and the groups associated with the device type of @dev
	 * to @kuid/@kgid.
	 */
	error = device_attrs_change_owner(dev, kuid, kgid);
	if (error)
		goto out;

	error = dpm_sysfs_change_owner(dev, kuid, kgid);
	if (error)
		goto out;

#ifdef CONFIG_BLOCK
	if (sysfs_deprecated && dev->class == &block_class)
		goto out;
#endif

	/*
	 * Change the owner of the symlink located in the class directory of
	 * the device class associated with @dev which points to the actual
	 * directory entry for @dev to @kuid/@kgid. This ensures that the
	 * symlink shows the same permissions as its target.
	 */
	error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
					dev_name(dev), kuid, kgid);
	if (error)
		goto out;

out:
	put_device(dev);
	return error;
}
EXPORT_SYMBOL_GPL(device_change_owner);

/**
 * device_shutdown - call ->shutdown() on each device to shutdown.
 */
void device_shutdown(void)
{
	struct device *dev, *parent;

	wait_for_device_probe();
	device_block_probing();

	cpufreq_suspend();

	spin_lock(&devices_kset->list_lock);
	/*
	 * Walk the devices list backward, shutting down each in turn.
	 * Beware that device unplug events may also start pulling
	 * devices offline, even as the system is shutting down.
	 */
	while (!list_empty(&devices_kset->list)) {
		dev = list_entry(devices_kset->list.prev, struct device,
				kobj.entry);

		/*
		 * hold reference count of device's parent to
		 * prevent it from being freed because parent's
		 * lock is to be held
		 */
		parent = get_device(dev->parent);
		get_device(dev);
		/*
		 * Make sure the device is off the kset list, in the
		 * event that dev->*->shutdown() doesn't remove it.
		 */
		list_del_init(&dev->kobj.entry);
		spin_unlock(&devices_kset->list_lock);

		/* hold lock to avoid race with probe/release */
		if (parent)
			device_lock(parent);
		device_lock(dev);

		/* Don't allow any more runtime suspends */
		pm_runtime_get_noresume(dev);
		pm_runtime_barrier(dev);

		if (dev->class && dev->class->shutdown_pre) {
			if (initcall_debug)
				dev_info(dev, "shutdown_pre\n");
			dev->class->shutdown_pre(dev);
		}
		if (dev->bus && dev->bus->shutdown) {
			if (initcall_debug)
				dev_info(dev, "shutdown\n");
			dev->bus->shutdown(dev);
		} else if (dev->driver && dev->driver->shutdown) {
			if (initcall_debug)
				dev_info(dev, "shutdown\n");
			dev->driver->shutdown(dev);
		}

		device_unlock(dev);
		if (parent)
			device_unlock(parent);

		put_device(dev);
		put_device(parent);

		spin_lock(&devices_kset->list_lock);
	}
	spin_unlock(&devices_kset->list_lock);
}

/*
 * Device logging functions
 */

#ifdef CONFIG_PRINTK
static int
create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
{
	const char *subsys;
	size_t pos = 0;

	if (dev->class)
		subsys = dev->class->name;
	else if (dev->bus)
		subsys = dev->bus->name;
	else
		return 0;

	pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
	if (pos >= hdrlen)
		goto overflow;

	/*
	 * Add device identifier DEVICE=:
	 *   b12:8         block dev_t
	 *   c127:3        char dev_t
	 *   n8            netdev ifindex
	 *   +sound:card0  subsystem:devname
	 */
	if (MAJOR(dev->devt)) {
		char c;

		if (strcmp(subsys, "block") == 0)
			c = 'b';
		else
			c = 'c';
		pos++;
		pos += snprintf(hdr + pos, hdrlen - pos,
				"DEVICE=%c%u:%u",
				c, MAJOR(dev->devt), MINOR(dev->devt));
	} else if (strcmp(subsys, "net") == 0) {
		struct net_device *net = to_net_dev(dev);

		pos++;
		pos += snprintf(hdr + pos, hdrlen - pos,
				"DEVICE=n%u", net->ifindex);
	} else {
		pos++;
		pos += snprintf(hdr + pos, hdrlen - pos,
				"DEVICE=+%s:%s", subsys, dev_name(dev));
	}

	if (pos >= hdrlen)
		goto overflow;

	return pos;

overflow:
	dev_WARN(dev, "device/subsystem name too long");
	return 0;
}

int dev_vprintk_emit(int level, const struct device *dev,
		     const char *fmt, va_list args)
{
	char hdr[128];
	size_t hdrlen;

	hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));

	return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
}
EXPORT_SYMBOL(dev_vprintk_emit);

int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
{
	va_list args;
	int r;

	va_start(args, fmt);

	r = dev_vprintk_emit(level, dev, fmt, args);

	va_end(args);

	return r;
}
EXPORT_SYMBOL(dev_printk_emit);

static void __dev_printk(const char *level, const struct device *dev,
			struct va_format *vaf)
{
	if (dev)
		dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
				dev_driver_string(dev), dev_name(dev), vaf);
	else
		printk("%s(NULL device *): %pV", level, vaf);
}

void dev_printk(const char *level, const struct device *dev,
		const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;

	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	__dev_printk(level, dev, &vaf);

	va_end(args);
}
EXPORT_SYMBOL(dev_printk);

#define define_dev_printk_level(func, kern_level)		\
void func(const struct device *dev, const char *fmt, ...)	\
{								\
	struct va_format vaf;					\
	va_list args;						\
								\
	va_start(args, fmt);					\
								\
	vaf.fmt = fmt;						\
	vaf.va = &args;						\
								\
	__dev_printk(kern_level, dev, &vaf);			\
								\
	va_end(args);						\
}								\
EXPORT_SYMBOL(func);

define_dev_printk_level(_dev_emerg, KERN_EMERG);
define_dev_printk_level(_dev_alert, KERN_ALERT);
define_dev_printk_level(_dev_crit, KERN_CRIT);
define_dev_printk_level(_dev_err, KERN_ERR);
define_dev_printk_level(_dev_warn, KERN_WARNING);
define_dev_printk_level(_dev_notice, KERN_NOTICE);
define_dev_printk_level(_dev_info, KERN_INFO);

#endif

static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
{
	return fwnode && !IS_ERR(fwnode->secondary);
}

/**
 * set_primary_fwnode - Change the primary firmware node of a given device.
 * @dev: Device to handle.
 * @fwnode: New primary firmware node of the device.
 *
 * Set the device's firmware node pointer to @fwnode, but if a secondary
 * firmware node of the device is present, preserve it.
 */
void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
{
	if (fwnode) {
		struct fwnode_handle *fn = dev->fwnode;

		if (fwnode_is_primary(fn))
			fn = fn->secondary;

		if (fn) {
			WARN_ON(fwnode->secondary);
			fwnode->secondary = fn;
		}
		dev->fwnode = fwnode;
	} else {
		dev->fwnode = fwnode_is_primary(dev->fwnode) ?
			dev->fwnode->secondary : NULL;
	}
}
EXPORT_SYMBOL_GPL(set_primary_fwnode);

/**
 * set_secondary_fwnode - Change the secondary firmware node of a given device.
 * @dev: Device to handle.
 * @fwnode: New secondary firmware node of the device.
 *
 * If a primary firmware node of the device is present, set its secondary
 * pointer to @fwnode.  Otherwise, set the device's firmware node pointer to
 * @fwnode.
 */
void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
{
	if (fwnode)
		fwnode->secondary = ERR_PTR(-ENODEV);

	if (fwnode_is_primary(dev->fwnode))
		dev->fwnode->secondary = fwnode;
	else
		dev->fwnode = fwnode;
}

/**
 * device_set_of_node_from_dev - reuse device-tree node of another device
 * @dev: device whose device-tree node is being set
 * @dev2: device whose device-tree node is being reused
 *
 * Takes another reference to the new device-tree node after first dropping
 * any reference held to the old node.
 */
void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
{
	of_node_put(dev->of_node);
	dev->of_node = of_node_get(dev2->of_node);
	dev->of_node_reused = true;
}
EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);

int device_match_name(struct device *dev, const void *name)
{
	return sysfs_streq(dev_name(dev), name);
}
EXPORT_SYMBOL_GPL(device_match_name);

int device_match_of_node(struct device *dev, const void *np)
{
	return dev->of_node == np;
}
EXPORT_SYMBOL_GPL(device_match_of_node);

int device_match_fwnode(struct device *dev, const void *fwnode)
{
	return dev_fwnode(dev) == fwnode;
}
EXPORT_SYMBOL_GPL(device_match_fwnode);

int device_match_devt(struct device *dev, const void *pdevt)
{
	return dev->devt == *(dev_t *)pdevt;
}
EXPORT_SYMBOL_GPL(device_match_devt);

int device_match_acpi_dev(struct device *dev, const void *adev)
{
	return ACPI_COMPANION(dev) == adev;
}
EXPORT_SYMBOL(device_match_acpi_dev);

int device_match_any(struct device *dev, const void *unused)
{
	return 1;
}
EXPORT_SYMBOL_GPL(device_match_any);