summaryrefslogtreecommitdiff
path: root/drivers/ata/libata-eh.c
blob: 938b6996c38fec1faea6c7d3e70635a076baeef9 (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
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
/*
 *  libata-eh.c - libata error handling
 *
 *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
 *    		    Please ALWAYS copy linux-ide@vger.kernel.org
 *		    on emails.
 *
 *  Copyright 2006 Tejun Heo <htejun@gmail.com>
 *
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License as
 *  published by the Free Software Foundation; either version 2, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
 *  USA.
 *
 *
 *  libata documentation is available via 'make {ps|pdf}docs',
 *  as Documentation/DocBook/libata.*
 *
 *  Hardware documentation available from http://www.t13.org/ and
 *  http://www.sata-io.org/
 *
 */

#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/export.h>
#include <linux/pci.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include "../scsi/scsi_transport_api.h"

#include <linux/libata.h>

#include "libata.h"

enum {
	/* speed down verdicts */
	ATA_EH_SPDN_NCQ_OFF		= (1 << 0),
	ATA_EH_SPDN_SPEED_DOWN		= (1 << 1),
	ATA_EH_SPDN_FALLBACK_TO_PIO	= (1 << 2),
	ATA_EH_SPDN_KEEP_ERRORS		= (1 << 3),

	/* error flags */
	ATA_EFLAG_IS_IO			= (1 << 0),
	ATA_EFLAG_DUBIOUS_XFER		= (1 << 1),
	ATA_EFLAG_OLD_ER                = (1 << 31),

	/* error categories */
	ATA_ECAT_NONE			= 0,
	ATA_ECAT_ATA_BUS		= 1,
	ATA_ECAT_TOUT_HSM		= 2,
	ATA_ECAT_UNK_DEV		= 3,
	ATA_ECAT_DUBIOUS_NONE		= 4,
	ATA_ECAT_DUBIOUS_ATA_BUS	= 5,
	ATA_ECAT_DUBIOUS_TOUT_HSM	= 6,
	ATA_ECAT_DUBIOUS_UNK_DEV	= 7,
	ATA_ECAT_NR			= 8,

	ATA_EH_CMD_DFL_TIMEOUT		=  5000,

	/* always put at least this amount of time between resets */
	ATA_EH_RESET_COOL_DOWN		=  5000,

	/* Waiting in ->prereset can never be reliable.  It's
	 * sometimes nice to wait there but it can't be depended upon;
	 * otherwise, we wouldn't be resetting.  Just give it enough
	 * time for most drives to spin up.
	 */
	ATA_EH_PRERESET_TIMEOUT		= 10000,
	ATA_EH_FASTDRAIN_INTERVAL	=  3000,

	ATA_EH_UA_TRIES			= 5,

	/* probe speed down parameters, see ata_eh_schedule_probe() */
	ATA_EH_PROBE_TRIAL_INTERVAL	= 60000,	/* 1 min */
	ATA_EH_PROBE_TRIALS		= 2,
};

/* The following table determines how we sequence resets.  Each entry
 * represents timeout for that try.  The first try can be soft or
 * hardreset.  All others are hardreset if available.  In most cases
 * the first reset w/ 10sec timeout should succeed.  Following entries
 * are mostly for error handling, hotplug and retarded devices.
 */
static const unsigned long ata_eh_reset_timeouts[] = {
	10000,	/* most drives spin up by 10sec */
	10000,	/* > 99% working drives spin up before 20sec */
	35000,	/* give > 30 secs of idleness for retarded devices */
	 5000,	/* and sweet one last chance */
	ULONG_MAX, /* > 1 min has elapsed, give up */
};

static const unsigned long ata_eh_identify_timeouts[] = {
	 5000,	/* covers > 99% of successes and not too boring on failures */
	10000,  /* combined time till here is enough even for media access */
	30000,	/* for true idiots */
	ULONG_MAX,
};

static const unsigned long ata_eh_flush_timeouts[] = {
	15000,	/* be generous with flush */
	15000,  /* ditto */
	30000,	/* and even more generous */
	ULONG_MAX,
};

static const unsigned long ata_eh_other_timeouts[] = {
	 5000,	/* same rationale as identify timeout */
	10000,	/* ditto */
	/* but no merciful 30sec for other commands, it just isn't worth it */
	ULONG_MAX,
};

struct ata_eh_cmd_timeout_ent {
	const u8		*commands;
	const unsigned long	*timeouts;
};

/* The following table determines timeouts to use for EH internal
 * commands.  Each table entry is a command class and matches the
 * commands the entry applies to and the timeout table to use.
 *
 * On the retry after a command timed out, the next timeout value from
 * the table is used.  If the table doesn't contain further entries,
 * the last value is used.
 *
 * ehc->cmd_timeout_idx keeps track of which timeout to use per
 * command class, so if SET_FEATURES times out on the first try, the
 * next try will use the second timeout value only for that class.
 */
#define CMDS(cmds...)	(const u8 []){ cmds, 0 }
static const struct ata_eh_cmd_timeout_ent
ata_eh_cmd_timeout_table[ATA_EH_CMD_TIMEOUT_TABLE_SIZE] = {
	{ .commands = CMDS(ATA_CMD_ID_ATA, ATA_CMD_ID_ATAPI),
	  .timeouts = ata_eh_identify_timeouts, },
	{ .commands = CMDS(ATA_CMD_READ_NATIVE_MAX, ATA_CMD_READ_NATIVE_MAX_EXT),
	  .timeouts = ata_eh_other_timeouts, },
	{ .commands = CMDS(ATA_CMD_SET_MAX, ATA_CMD_SET_MAX_EXT),
	  .timeouts = ata_eh_other_timeouts, },
	{ .commands = CMDS(ATA_CMD_SET_FEATURES),
	  .timeouts = ata_eh_other_timeouts, },
	{ .commands = CMDS(ATA_CMD_INIT_DEV_PARAMS),
	  .timeouts = ata_eh_other_timeouts, },
	{ .commands = CMDS(ATA_CMD_FLUSH, ATA_CMD_FLUSH_EXT),
	  .timeouts = ata_eh_flush_timeouts },
};
#undef CMDS

static void __ata_port_freeze(struct ata_port *ap);
#ifdef CONFIG_PM
static void ata_eh_handle_port_suspend(struct ata_port *ap);
static void ata_eh_handle_port_resume(struct ata_port *ap);
#else /* CONFIG_PM */
static void ata_eh_handle_port_suspend(struct ata_port *ap)
{ }

static void ata_eh_handle_port_resume(struct ata_port *ap)
{ }
#endif /* CONFIG_PM */

static void __ata_ehi_pushv_desc(struct ata_eh_info *ehi, const char *fmt,
				 va_list args)
{
	ehi->desc_len += vscnprintf(ehi->desc + ehi->desc_len,
				     ATA_EH_DESC_LEN - ehi->desc_len,
				     fmt, args);
}

/**
 *	__ata_ehi_push_desc - push error description without adding separator
 *	@ehi: target EHI
 *	@fmt: printf format string
 *
 *	Format string according to @fmt and append it to @ehi->desc.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
void __ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	__ata_ehi_pushv_desc(ehi, fmt, args);
	va_end(args);
}

/**
 *	ata_ehi_push_desc - push error description with separator
 *	@ehi: target EHI
 *	@fmt: printf format string
 *
 *	Format string according to @fmt and append it to @ehi->desc.
 *	If @ehi->desc is not empty, ", " is added in-between.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
void ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
{
	va_list args;

	if (ehi->desc_len)
		__ata_ehi_push_desc(ehi, ", ");

	va_start(args, fmt);
	__ata_ehi_pushv_desc(ehi, fmt, args);
	va_end(args);
}

/**
 *	ata_ehi_clear_desc - clean error description
 *	@ehi: target EHI
 *
 *	Clear @ehi->desc.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
void ata_ehi_clear_desc(struct ata_eh_info *ehi)
{
	ehi->desc[0] = '\0';
	ehi->desc_len = 0;
}

/**
 *	ata_port_desc - append port description
 *	@ap: target ATA port
 *	@fmt: printf format string
 *
 *	Format string according to @fmt and append it to port
 *	description.  If port description is not empty, " " is added
 *	in-between.  This function is to be used while initializing
 *	ata_host.  The description is printed on host registration.
 *
 *	LOCKING:
 *	None.
 */
void ata_port_desc(struct ata_port *ap, const char *fmt, ...)
{
	va_list args;

	WARN_ON(!(ap->pflags & ATA_PFLAG_INITIALIZING));

	if (ap->link.eh_info.desc_len)
		__ata_ehi_push_desc(&ap->link.eh_info, " ");

	va_start(args, fmt);
	__ata_ehi_pushv_desc(&ap->link.eh_info, fmt, args);
	va_end(args);
}

#ifdef CONFIG_PCI

/**
 *	ata_port_pbar_desc - append PCI BAR description
 *	@ap: target ATA port
 *	@bar: target PCI BAR
 *	@offset: offset into PCI BAR
 *	@name: name of the area
 *
 *	If @offset is negative, this function formats a string which
 *	contains the name, address, size and type of the BAR and
 *	appends it to the port description.  If @offset is zero or
 *	positive, only name and offsetted address is appended.
 *
 *	LOCKING:
 *	None.
 */
void ata_port_pbar_desc(struct ata_port *ap, int bar, ssize_t offset,
			const char *name)
{
	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
	char *type = "";
	unsigned long long start, len;

	if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)
		type = "m";
	else if (pci_resource_flags(pdev, bar) & IORESOURCE_IO)
		type = "i";

	start = (unsigned long long)pci_resource_start(pdev, bar);
	len = (unsigned long long)pci_resource_len(pdev, bar);

	if (offset < 0)
		ata_port_desc(ap, "%s %s%llu@0x%llx", name, type, len, start);
	else
		ata_port_desc(ap, "%s 0x%llx", name,
				start + (unsigned long long)offset);
}

#endif /* CONFIG_PCI */

static int ata_lookup_timeout_table(u8 cmd)
{
	int i;

	for (i = 0; i < ATA_EH_CMD_TIMEOUT_TABLE_SIZE; i++) {
		const u8 *cur;

		for (cur = ata_eh_cmd_timeout_table[i].commands; *cur; cur++)
			if (*cur == cmd)
				return i;
	}

	return -1;
}

/**
 *	ata_internal_cmd_timeout - determine timeout for an internal command
 *	@dev: target device
 *	@cmd: internal command to be issued
 *
 *	Determine timeout for internal command @cmd for @dev.
 *
 *	LOCKING:
 *	EH context.
 *
 *	RETURNS:
 *	Determined timeout.
 */
unsigned long ata_internal_cmd_timeout(struct ata_device *dev, u8 cmd)
{
	struct ata_eh_context *ehc = &dev->link->eh_context;
	int ent = ata_lookup_timeout_table(cmd);
	int idx;

	if (ent < 0)
		return ATA_EH_CMD_DFL_TIMEOUT;

	idx = ehc->cmd_timeout_idx[dev->devno][ent];
	return ata_eh_cmd_timeout_table[ent].timeouts[idx];
}

/**
 *	ata_internal_cmd_timed_out - notification for internal command timeout
 *	@dev: target device
 *	@cmd: internal command which timed out
 *
 *	Notify EH that internal command @cmd for @dev timed out.  This
 *	function should be called only for commands whose timeouts are
 *	determined using ata_internal_cmd_timeout().
 *
 *	LOCKING:
 *	EH context.
 */
void ata_internal_cmd_timed_out(struct ata_device *dev, u8 cmd)
{
	struct ata_eh_context *ehc = &dev->link->eh_context;
	int ent = ata_lookup_timeout_table(cmd);
	int idx;

	if (ent < 0)
		return;

	idx = ehc->cmd_timeout_idx[dev->devno][ent];
	if (ata_eh_cmd_timeout_table[ent].timeouts[idx + 1] != ULONG_MAX)
		ehc->cmd_timeout_idx[dev->devno][ent]++;
}

static void ata_ering_record(struct ata_ering *ering, unsigned int eflags,
			     unsigned int err_mask)
{
	struct ata_ering_entry *ent;

	WARN_ON(!err_mask);

	ering->cursor++;
	ering->cursor %= ATA_ERING_SIZE;

	ent = &ering->ring[ering->cursor];
	ent->eflags = eflags;
	ent->err_mask = err_mask;
	ent->timestamp = get_jiffies_64();
}

static struct ata_ering_entry *ata_ering_top(struct ata_ering *ering)
{
	struct ata_ering_entry *ent = &ering->ring[ering->cursor];

	if (ent->err_mask)
		return ent;
	return NULL;
}

int ata_ering_map(struct ata_ering *ering,
		  int (*map_fn)(struct ata_ering_entry *, void *),
		  void *arg)
{
	int idx, rc = 0;
	struct ata_ering_entry *ent;

	idx = ering->cursor;
	do {
		ent = &ering->ring[idx];
		if (!ent->err_mask)
			break;
		rc = map_fn(ent, arg);
		if (rc)
			break;
		idx = (idx - 1 + ATA_ERING_SIZE) % ATA_ERING_SIZE;
	} while (idx != ering->cursor);

	return rc;
}

static int ata_ering_clear_cb(struct ata_ering_entry *ent, void *void_arg)
{
	ent->eflags |= ATA_EFLAG_OLD_ER;
	return 0;
}

static void ata_ering_clear(struct ata_ering *ering)
{
	ata_ering_map(ering, ata_ering_clear_cb, NULL);
}

static unsigned int ata_eh_dev_action(struct ata_device *dev)
{
	struct ata_eh_context *ehc = &dev->link->eh_context;

	return ehc->i.action | ehc->i.dev_action[dev->devno];
}

static void ata_eh_clear_action(struct ata_link *link, struct ata_device *dev,
				struct ata_eh_info *ehi, unsigned int action)
{
	struct ata_device *tdev;

	if (!dev) {
		ehi->action &= ~action;
		ata_for_each_dev(tdev, link, ALL)
			ehi->dev_action[tdev->devno] &= ~action;
	} else {
		/* doesn't make sense for port-wide EH actions */
		WARN_ON(!(action & ATA_EH_PERDEV_MASK));

		/* break ehi->action into ehi->dev_action */
		if (ehi->action & action) {
			ata_for_each_dev(tdev, link, ALL)
				ehi->dev_action[tdev->devno] |=
					ehi->action & action;
			ehi->action &= ~action;
		}

		/* turn off the specified per-dev action */
		ehi->dev_action[dev->devno] &= ~action;
	}
}

/**
 *	ata_eh_acquire - acquire EH ownership
 *	@ap: ATA port to acquire EH ownership for
 *
 *	Acquire EH ownership for @ap.  This is the basic exclusion
 *	mechanism for ports sharing a host.  Only one port hanging off
 *	the same host can claim the ownership of EH.
 *
 *	LOCKING:
 *	EH context.
 */
void ata_eh_acquire(struct ata_port *ap)
{
	mutex_lock(&ap->host->eh_mutex);
	WARN_ON_ONCE(ap->host->eh_owner);
	ap->host->eh_owner = current;
}

/**
 *	ata_eh_release - release EH ownership
 *	@ap: ATA port to release EH ownership for
 *
 *	Release EH ownership for @ap if the caller.  The caller must
 *	have acquired EH ownership using ata_eh_acquire() previously.
 *
 *	LOCKING:
 *	EH context.
 */
void ata_eh_release(struct ata_port *ap)
{
	WARN_ON_ONCE(ap->host->eh_owner != current);
	ap->host->eh_owner = NULL;
	mutex_unlock(&ap->host->eh_mutex);
}

/**
 *	ata_scsi_timed_out - SCSI layer time out callback
 *	@cmd: timed out SCSI command
 *
 *	Handles SCSI layer timeout.  We race with normal completion of
 *	the qc for @cmd.  If the qc is already gone, we lose and let
 *	the scsi command finish (EH_HANDLED).  Otherwise, the qc has
 *	timed out and EH should be invoked.  Prevent ata_qc_complete()
 *	from finishing it by setting EH_SCHEDULED and return
 *	EH_NOT_HANDLED.
 *
 *	TODO: kill this function once old EH is gone.
 *
 *	LOCKING:
 *	Called from timer context
 *
 *	RETURNS:
 *	EH_HANDLED or EH_NOT_HANDLED
 */
enum blk_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd)
{
	struct Scsi_Host *host = cmd->device->host;
	struct ata_port *ap = ata_shost_to_port(host);
	unsigned long flags;
	struct ata_queued_cmd *qc;
	enum blk_eh_timer_return ret;

	DPRINTK("ENTER\n");

	if (ap->ops->error_handler) {
		ret = BLK_EH_NOT_HANDLED;
		goto out;
	}

	ret = BLK_EH_HANDLED;
	spin_lock_irqsave(ap->lock, flags);
	qc = ata_qc_from_tag(ap, ap->link.active_tag);
	if (qc) {
		WARN_ON(qc->scsicmd != cmd);
		qc->flags |= ATA_QCFLAG_EH_SCHEDULED;
		qc->err_mask |= AC_ERR_TIMEOUT;
		ret = BLK_EH_NOT_HANDLED;
	}
	spin_unlock_irqrestore(ap->lock, flags);

 out:
	DPRINTK("EXIT, ret=%d\n", ret);
	return ret;
}

static void ata_eh_unload(struct ata_port *ap)
{
	struct ata_link *link;
	struct ata_device *dev;
	unsigned long flags;

	/* Restore SControl IPM and SPD for the next driver and
	 * disable attached devices.
	 */
	ata_for_each_link(link, ap, PMP_FIRST) {
		sata_scr_write(link, SCR_CONTROL, link->saved_scontrol & 0xff0);
		ata_for_each_dev(dev, link, ALL)
			ata_dev_disable(dev);
	}

	/* freeze and set UNLOADED */
	spin_lock_irqsave(ap->lock, flags);

	ata_port_freeze(ap);			/* won't be thawed */
	ap->pflags &= ~ATA_PFLAG_EH_PENDING;	/* clear pending from freeze */
	ap->pflags |= ATA_PFLAG_UNLOADED;

	spin_unlock_irqrestore(ap->lock, flags);
}

/**
 *	ata_scsi_error - SCSI layer error handler callback
 *	@host: SCSI host on which error occurred
 *
 *	Handles SCSI-layer-thrown error events.
 *
 *	LOCKING:
 *	Inherited from SCSI layer (none, can sleep)
 *
 *	RETURNS:
 *	Zero.
 */
void ata_scsi_error(struct Scsi_Host *host)
{
	struct ata_port *ap = ata_shost_to_port(host);
	unsigned long flags;
	LIST_HEAD(eh_work_q);

	DPRINTK("ENTER\n");

	spin_lock_irqsave(host->host_lock, flags);
	list_splice_init(&host->eh_cmd_q, &eh_work_q);
	spin_unlock_irqrestore(host->host_lock, flags);

	ata_scsi_cmd_error_handler(host, ap, &eh_work_q);

	/* If we timed raced normal completion and there is nothing to
	   recover nr_timedout == 0 why exactly are we doing error recovery ? */
	ata_scsi_port_error_handler(host, ap);

	/* finish or retry handled scmd's and clean up */
	WARN_ON(host->host_failed || !list_empty(&eh_work_q));

	DPRINTK("EXIT\n");
}

/**
 * ata_scsi_cmd_error_handler - error callback for a list of commands
 * @host:	scsi host containing the port
 * @ap:		ATA port within the host
 * @eh_work_q:	list of commands to process
 *
 * process the given list of commands and return those finished to the
 * ap->eh_done_q.  This function is the first part of the libata error
 * handler which processes a given list of failed commands.
 */
void ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap,
				struct list_head *eh_work_q)
{
	int i;
	unsigned long flags;

	/* make sure sff pio task is not running */
	ata_sff_flush_pio_task(ap);

	/* synchronize with host lock and sort out timeouts */

	/* For new EH, all qcs are finished in one of three ways -
	 * normal completion, error completion, and SCSI timeout.
	 * Both completions can race against SCSI timeout.  When normal
	 * completion wins, the qc never reaches EH.  When error
	 * completion wins, the qc has ATA_QCFLAG_FAILED set.
	 *
	 * When SCSI timeout wins, things are a bit more complex.
	 * Normal or error completion can occur after the timeout but
	 * before this point.  In such cases, both types of
	 * completions are honored.  A scmd is determined to have
	 * timed out iff its associated qc is active and not failed.
	 */
	if (ap->ops->error_handler) {
		struct scsi_cmnd *scmd, *tmp;
		int nr_timedout = 0;

		spin_lock_irqsave(ap->lock, flags);

		/* This must occur under the ap->lock as we don't want
		   a polled recovery to race the real interrupt handler

		   The lost_interrupt handler checks for any completed but
		   non-notified command and completes much like an IRQ handler.

		   We then fall into the error recovery code which will treat
		   this as if normal completion won the race */

		if (ap->ops->lost_interrupt)
			ap->ops->lost_interrupt(ap);

		list_for_each_entry_safe(scmd, tmp, eh_work_q, eh_entry) {
			struct ata_queued_cmd *qc;

			for (i = 0; i < ATA_MAX_QUEUE; i++) {
				qc = __ata_qc_from_tag(ap, i);
				if (qc->flags & ATA_QCFLAG_ACTIVE &&
				    qc->scsicmd == scmd)
					break;
			}

			if (i < ATA_MAX_QUEUE) {
				/* the scmd has an associated qc */
				if (!(qc->flags & ATA_QCFLAG_FAILED)) {
					/* which hasn't failed yet, timeout */
					qc->err_mask |= AC_ERR_TIMEOUT;
					qc->flags |= ATA_QCFLAG_FAILED;
					nr_timedout++;
				}
			} else {
				/* Normal completion occurred after
				 * SCSI timeout but before this point.
				 * Successfully complete it.
				 */
				scmd->retries = scmd->allowed;
				scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
			}
		}

		/* If we have timed out qcs.  They belong to EH from
		 * this point but the state of the controller is
		 * unknown.  Freeze the port to make sure the IRQ
		 * handler doesn't diddle with those qcs.  This must
		 * be done atomically w.r.t. setting QCFLAG_FAILED.
		 */
		if (nr_timedout)
			__ata_port_freeze(ap);

		spin_unlock_irqrestore(ap->lock, flags);

		/* initialize eh_tries */
		ap->eh_tries = ATA_EH_MAX_TRIES;
	} else
		spin_unlock_wait(ap->lock);

}
EXPORT_SYMBOL(ata_scsi_cmd_error_handler);

/**
 * ata_scsi_port_error_handler - recover the port after the commands
 * @host:	SCSI host containing the port
 * @ap:		the ATA port
 *
 * Handle the recovery of the port @ap after all the commands
 * have been recovered.
 */
void ata_scsi_port_error_handler(struct Scsi_Host *host, struct ata_port *ap)
{
	unsigned long flags;

	/* invoke error handler */
	if (ap->ops->error_handler) {
		struct ata_link *link;

		/* acquire EH ownership */
		ata_eh_acquire(ap);
 repeat:
		/* kill fast drain timer */
		del_timer_sync(&ap->fastdrain_timer);

		/* process port resume request */
		ata_eh_handle_port_resume(ap);

		/* fetch & clear EH info */
		spin_lock_irqsave(ap->lock, flags);

		ata_for_each_link(link, ap, HOST_FIRST) {
			struct ata_eh_context *ehc = &link->eh_context;
			struct ata_device *dev;

			memset(&link->eh_context, 0, sizeof(link->eh_context));
			link->eh_context.i = link->eh_info;
			memset(&link->eh_info, 0, sizeof(link->eh_info));

			ata_for_each_dev(dev, link, ENABLED) {
				int devno = dev->devno;

				ehc->saved_xfer_mode[devno] = dev->xfer_mode;
				if (ata_ncq_enabled(dev))
					ehc->saved_ncq_enabled |= 1 << devno;
			}
		}

		ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;
		ap->pflags &= ~ATA_PFLAG_EH_PENDING;
		ap->excl_link = NULL;	/* don't maintain exclusion over EH */

		spin_unlock_irqrestore(ap->lock, flags);

		/* invoke EH, skip if unloading or suspended */
		if (!(ap->pflags & (ATA_PFLAG_UNLOADING | ATA_PFLAG_SUSPENDED)))
			ap->ops->error_handler(ap);
		else {
			/* if unloading, commence suicide */
			if ((ap->pflags & ATA_PFLAG_UNLOADING) &&
			    !(ap->pflags & ATA_PFLAG_UNLOADED))
				ata_eh_unload(ap);
			ata_eh_finish(ap);
		}

		/* process port suspend request */
		ata_eh_handle_port_suspend(ap);

		/* Exception might have happened after ->error_handler
		 * recovered the port but before this point.  Repeat
		 * EH in such case.
		 */
		spin_lock_irqsave(ap->lock, flags);

		if (ap->pflags & ATA_PFLAG_EH_PENDING) {
			if (--ap->eh_tries) {
				spin_unlock_irqrestore(ap->lock, flags);
				goto repeat;
			}
			ata_port_err(ap,
				     "EH pending after %d tries, giving up\n",
				     ATA_EH_MAX_TRIES);
			ap->pflags &= ~ATA_PFLAG_EH_PENDING;
		}

		/* this run is complete, make sure EH info is clear */
		ata_for_each_link(link, ap, HOST_FIRST)
			memset(&link->eh_info, 0, sizeof(link->eh_info));

		/* Clear host_eh_scheduled while holding ap->lock such
		 * that if exception occurs after this point but
		 * before EH completion, SCSI midlayer will
		 * re-initiate EH.
		 */
		host->host_eh_scheduled = 0;

		spin_unlock_irqrestore(ap->lock, flags);
		ata_eh_release(ap);
	} else {
		WARN_ON(ata_qc_from_tag(ap, ap->link.active_tag) == NULL);
		ap->ops->eng_timeout(ap);
	}

	scsi_eh_flush_done_q(&ap->eh_done_q);

	/* clean up */
	spin_lock_irqsave(ap->lock, flags);

	if (ap->pflags & ATA_PFLAG_LOADING)
		ap->pflags &= ~ATA_PFLAG_LOADING;
	else if (ap->pflags & ATA_PFLAG_SCSI_HOTPLUG)
		schedule_delayed_work(&ap->hotplug_task, 0);

	if (ap->pflags & ATA_PFLAG_RECOVERED)
		ata_port_info(ap, "EH complete\n");

	ap->pflags &= ~(ATA_PFLAG_SCSI_HOTPLUG | ATA_PFLAG_RECOVERED);

	/* tell wait_eh that we're done */
	ap->pflags &= ~ATA_PFLAG_EH_IN_PROGRESS;
	wake_up_all(&ap->eh_wait_q);

	spin_unlock_irqrestore(ap->lock, flags);
}
EXPORT_SYMBOL_GPL(ata_scsi_port_error_handler);

/**
 *	ata_port_wait_eh - Wait for the currently pending EH to complete
 *	@ap: Port to wait EH for
 *
 *	Wait until the currently pending EH is complete.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
void ata_port_wait_eh(struct ata_port *ap)
{
	unsigned long flags;
	DEFINE_WAIT(wait);

 retry:
	spin_lock_irqsave(ap->lock, flags);

	while (ap->pflags & (ATA_PFLAG_EH_PENDING | ATA_PFLAG_EH_IN_PROGRESS)) {
		prepare_to_wait(&ap->eh_wait_q, &wait, TASK_UNINTERRUPTIBLE);
		spin_unlock_irqrestore(ap->lock, flags);
		schedule();
		spin_lock_irqsave(ap->lock, flags);
	}
	finish_wait(&ap->eh_wait_q, &wait);

	spin_unlock_irqrestore(ap->lock, flags);

	/* make sure SCSI EH is complete */
	if (scsi_host_in_recovery(ap->scsi_host)) {
		ata_msleep(ap, 10);
		goto retry;
	}
}
EXPORT_SYMBOL_GPL(ata_port_wait_eh);

static int ata_eh_nr_in_flight(struct ata_port *ap)
{
	unsigned int tag;
	int nr = 0;

	/* count only non-internal commands */
	for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++)
		if (ata_qc_from_tag(ap, tag))
			nr++;

	return nr;
}

void ata_eh_fastdrain_timerfn(unsigned long arg)
{
	struct ata_port *ap = (void *)arg;
	unsigned long flags;
	int cnt;

	spin_lock_irqsave(ap->lock, flags);

	cnt = ata_eh_nr_in_flight(ap);

	/* are we done? */
	if (!cnt)
		goto out_unlock;

	if (cnt == ap->fastdrain_cnt) {
		unsigned int tag;

		/* No progress during the last interval, tag all
		 * in-flight qcs as timed out and freeze the port.
		 */
		for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++) {
			struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
			if (qc)
				qc->err_mask |= AC_ERR_TIMEOUT;
		}

		ata_port_freeze(ap);
	} else {
		/* some qcs have finished, give it another chance */
		ap->fastdrain_cnt = cnt;
		ap->fastdrain_timer.expires =
			ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
		add_timer(&ap->fastdrain_timer);
	}

 out_unlock:
	spin_unlock_irqrestore(ap->lock, flags);
}

/**
 *	ata_eh_set_pending - set ATA_PFLAG_EH_PENDING and activate fast drain
 *	@ap: target ATA port
 *	@fastdrain: activate fast drain
 *
 *	Set ATA_PFLAG_EH_PENDING and activate fast drain if @fastdrain
 *	is non-zero and EH wasn't pending before.  Fast drain ensures
 *	that EH kicks in in timely manner.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static void ata_eh_set_pending(struct ata_port *ap, int fastdrain)
{
	int cnt;

	/* already scheduled? */
	if (ap->pflags & ATA_PFLAG_EH_PENDING)
		return;

	ap->pflags |= ATA_PFLAG_EH_PENDING;

	if (!fastdrain)
		return;

	/* do we have in-flight qcs? */
	cnt = ata_eh_nr_in_flight(ap);
	if (!cnt)
		return;

	/* activate fast drain */
	ap->fastdrain_cnt = cnt;
	ap->fastdrain_timer.expires =
		ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
	add_timer(&ap->fastdrain_timer);
}

/**
 *	ata_qc_schedule_eh - schedule qc for error handling
 *	@qc: command to schedule error handling for
 *
 *	Schedule error handling for @qc.  EH will kick in as soon as
 *	other commands are drained.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
void ata_qc_schedule_eh(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	struct request_queue *q = qc->scsicmd->device->request_queue;
	unsigned long flags;

	WARN_ON(!ap->ops->error_handler);

	qc->flags |= ATA_QCFLAG_FAILED;
	ata_eh_set_pending(ap, 1);

	/* The following will fail if timeout has already expired.
	 * ata_scsi_error() takes care of such scmds on EH entry.
	 * Note that ATA_QCFLAG_FAILED is unconditionally set after
	 * this function completes.
	 */
	spin_lock_irqsave(q->queue_lock, flags);
	blk_abort_request(qc->scsicmd->request);
	spin_unlock_irqrestore(q->queue_lock, flags);
}

/**
 *	ata_port_schedule_eh - schedule error handling without a qc
 *	@ap: ATA port to schedule EH for
 *
 *	Schedule error handling for @ap.  EH will kick in as soon as
 *	all commands are drained.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
void ata_port_schedule_eh(struct ata_port *ap)
{
	WARN_ON(!ap->ops->error_handler);

	if (ap->pflags & ATA_PFLAG_INITIALIZING)
		return;

	ata_eh_set_pending(ap, 1);
	scsi_schedule_eh(ap->scsi_host);

	DPRINTK("port EH scheduled\n");
}

static int ata_do_link_abort(struct ata_port *ap, struct ata_link *link)
{
	int tag, nr_aborted = 0;

	WARN_ON(!ap->ops->error_handler);

	/* we're gonna abort all commands, no need for fast drain */
	ata_eh_set_pending(ap, 0);

	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
		struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);

		if (qc && (!link || qc->dev->link == link)) {
			qc->flags |= ATA_QCFLAG_FAILED;
			ata_qc_complete(qc);
			nr_aborted++;
		}
	}

	if (!nr_aborted)
		ata_port_schedule_eh(ap);

	return nr_aborted;
}

/**
 *	ata_link_abort - abort all qc's on the link
 *	@link: ATA link to abort qc's for
 *
 *	Abort all active qc's active on @link and schedule EH.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	Number of aborted qc's.
 */
int ata_link_abort(struct ata_link *link)
{
	return ata_do_link_abort(link->ap, link);
}

/**
 *	ata_port_abort - abort all qc's on the port
 *	@ap: ATA port to abort qc's for
 *
 *	Abort all active qc's of @ap and schedule EH.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 *
 *	RETURNS:
 *	Number of aborted qc's.
 */
int ata_port_abort(struct ata_port *ap)
{
	return ata_do_link_abort(ap, NULL);
}

/**
 *	__ata_port_freeze - freeze port
 *	@ap: ATA port to freeze
 *
 *	This function is called when HSM violation or some other
 *	condition disrupts normal operation of the port.  Frozen port
 *	is not allowed to perform any operation until the port is
 *	thawed, which usually follows a successful reset.
 *
 *	ap->ops->freeze() callback can be used for freezing the port
 *	hardware-wise (e.g. mask interrupt and stop DMA engine).  If a
 *	port cannot be frozen hardware-wise, the interrupt handler
 *	must ack and clear interrupts unconditionally while the port
 *	is frozen.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 */
static void __ata_port_freeze(struct ata_port *ap)
{
	WARN_ON(!ap->ops->error_handler);

	if (ap->ops->freeze)
		ap->ops->freeze(ap);

	ap->pflags |= ATA_PFLAG_FROZEN;

	DPRINTK("ata%u port frozen\n", ap->print_id);
}

/**
 *	ata_port_freeze - abort & freeze port
 *	@ap: ATA port to freeze
 *
 *	Abort and freeze @ap.  The freeze operation must be called
 *	first, because some hardware requires special operations
 *	before the taskfile registers are accessible.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	Number of aborted commands.
 */
int ata_port_freeze(struct ata_port *ap)
{
	int nr_aborted;

	WARN_ON(!ap->ops->error_handler);

	__ata_port_freeze(ap);
	nr_aborted = ata_port_abort(ap);

	return nr_aborted;
}

/**
 *	sata_async_notification - SATA async notification handler
 *	@ap: ATA port where async notification is received
 *
 *	Handler to be called when async notification via SDB FIS is
 *	received.  This function schedules EH if necessary.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	1 if EH is scheduled, 0 otherwise.
 */
int sata_async_notification(struct ata_port *ap)
{
	u32 sntf;
	int rc;

	if (!(ap->flags & ATA_FLAG_AN))
		return 0;

	rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
	if (rc == 0)
		sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);

	if (!sata_pmp_attached(ap) || rc) {
		/* PMP is not attached or SNTF is not available */
		if (!sata_pmp_attached(ap)) {
			/* PMP is not attached.  Check whether ATAPI
			 * AN is configured.  If so, notify media
			 * change.
			 */
			struct ata_device *dev = ap->link.device;

			if ((dev->class == ATA_DEV_ATAPI) &&
			    (dev->flags & ATA_DFLAG_AN))
				ata_scsi_media_change_notify(dev);
			return 0;
		} else {
			/* PMP is attached but SNTF is not available.
			 * ATAPI async media change notification is
			 * not used.  The PMP must be reporting PHY
			 * status change, schedule EH.
			 */
			ata_port_schedule_eh(ap);
			return 1;
		}
	} else {
		/* PMP is attached and SNTF is available */
		struct ata_link *link;

		/* check and notify ATAPI AN */
		ata_for_each_link(link, ap, EDGE) {
			if (!(sntf & (1 << link->pmp)))
				continue;

			if ((link->device->class == ATA_DEV_ATAPI) &&
			    (link->device->flags & ATA_DFLAG_AN))
				ata_scsi_media_change_notify(link->device);
		}

		/* If PMP is reporting that PHY status of some
		 * downstream ports has changed, schedule EH.
		 */
		if (sntf & (1 << SATA_PMP_CTRL_PORT)) {
			ata_port_schedule_eh(ap);
			return 1;
		}

		return 0;
	}
}

/**
 *	ata_eh_freeze_port - EH helper to freeze port
 *	@ap: ATA port to freeze
 *
 *	Freeze @ap.
 *
 *	LOCKING:
 *	None.
 */
void ata_eh_freeze_port(struct ata_port *ap)
{
	unsigned long flags;

	if (!ap->ops->error_handler)
		return;

	spin_lock_irqsave(ap->lock, flags);
	__ata_port_freeze(ap);
	spin_unlock_irqrestore(ap->lock, flags);
}

/**
 *	ata_port_thaw_port - EH helper to thaw port
 *	@ap: ATA port to thaw
 *
 *	Thaw frozen port @ap.
 *
 *	LOCKING:
 *	None.
 */
void ata_eh_thaw_port(struct ata_port *ap)
{
	unsigned long flags;

	if (!ap->ops->error_handler)
		return;

	spin_lock_irqsave(ap->lock, flags);

	ap->pflags &= ~ATA_PFLAG_FROZEN;

	if (ap->ops->thaw)
		ap->ops->thaw(ap);

	spin_unlock_irqrestore(ap->lock, flags);

	DPRINTK("ata%u port thawed\n", ap->print_id);
}

static void ata_eh_scsidone(struct scsi_cmnd *scmd)
{
	/* nada */
}

static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	struct scsi_cmnd *scmd = qc->scsicmd;
	unsigned long flags;

	spin_lock_irqsave(ap->lock, flags);
	qc->scsidone = ata_eh_scsidone;
	__ata_qc_complete(qc);
	WARN_ON(ata_tag_valid(qc->tag));
	spin_unlock_irqrestore(ap->lock, flags);

	scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
}

/**
 *	ata_eh_qc_complete - Complete an active ATA command from EH
 *	@qc: Command to complete
 *
 *	Indicate to the mid and upper layers that an ATA command has
 *	completed.  To be used from EH.
 */
void ata_eh_qc_complete(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *scmd = qc->scsicmd;
	scmd->retries = scmd->allowed;
	__ata_eh_qc_complete(qc);
}

/**
 *	ata_eh_qc_retry - Tell midlayer to retry an ATA command after EH
 *	@qc: Command to retry
 *
 *	Indicate to the mid and upper layers that an ATA command
 *	should be retried.  To be used from EH.
 *
 *	SCSI midlayer limits the number of retries to scmd->allowed.
 *	scmd->retries is decremented for commands which get retried
 *	due to unrelated failures (qc->err_mask is zero).
 */
void ata_eh_qc_retry(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *scmd = qc->scsicmd;
	if (!qc->err_mask && scmd->retries)
		scmd->retries--;
	__ata_eh_qc_complete(qc);
}

/**
 *	ata_dev_disable - disable ATA device
 *	@dev: ATA device to disable
 *
 *	Disable @dev.
 *
 *	Locking:
 *	EH context.
 */
void ata_dev_disable(struct ata_device *dev)
{
	if (!ata_dev_enabled(dev))
		return;

	if (ata_msg_drv(dev->link->ap))
		ata_dev_warn(dev, "disabled\n");
	ata_acpi_on_disable(dev);
	ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 | ATA_DNXFER_QUIET);
	dev->class++;

	/* From now till the next successful probe, ering is used to
	 * track probe failures.  Clear accumulated device error info.
	 */
	ata_ering_clear(&dev->ering);
}

/**
 *	ata_eh_detach_dev - detach ATA device
 *	@dev: ATA device to detach
 *
 *	Detach @dev.
 *
 *	LOCKING:
 *	None.
 */
void ata_eh_detach_dev(struct ata_device *dev)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	struct ata_eh_context *ehc = &link->eh_context;
	unsigned long flags;

	ata_dev_disable(dev);

	spin_lock_irqsave(ap->lock, flags);

	dev->flags &= ~ATA_DFLAG_DETACH;

	if (ata_scsi_offline_dev(dev)) {
		dev->flags |= ATA_DFLAG_DETACHED;
		ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
	}

	/* clear per-dev EH info */
	ata_eh_clear_action(link, dev, &link->eh_info, ATA_EH_PERDEV_MASK);
	ata_eh_clear_action(link, dev, &link->eh_context.i, ATA_EH_PERDEV_MASK);
	ehc->saved_xfer_mode[dev->devno] = 0;
	ehc->saved_ncq_enabled &= ~(1 << dev->devno);

	spin_unlock_irqrestore(ap->lock, flags);
}

/**
 *	ata_eh_about_to_do - about to perform eh_action
 *	@link: target ATA link
 *	@dev: target ATA dev for per-dev action (can be NULL)
 *	@action: action about to be performed
 *
 *	Called just before performing EH actions to clear related bits
 *	in @link->eh_info such that eh actions are not unnecessarily
 *	repeated.
 *
 *	LOCKING:
 *	None.
 */
void ata_eh_about_to_do(struct ata_link *link, struct ata_device *dev,
			unsigned int action)
{
	struct ata_port *ap = link->ap;
	struct ata_eh_info *ehi = &link->eh_info;
	struct ata_eh_context *ehc = &link->eh_context;
	unsigned long flags;

	spin_lock_irqsave(ap->lock, flags);

	ata_eh_clear_action(link, dev, ehi, action);

	/* About to take EH action, set RECOVERED.  Ignore actions on
	 * slave links as master will do them again.
	 */
	if (!(ehc->i.flags & ATA_EHI_QUIET) && link != ap->slave_link)
		ap->pflags |= ATA_PFLAG_RECOVERED;

	spin_unlock_irqrestore(ap->lock, flags);
}

/**
 *	ata_eh_done - EH action complete
*	@ap: target ATA port
 *	@dev: target ATA dev for per-dev action (can be NULL)
 *	@action: action just completed
 *
 *	Called right after performing EH actions to clear related bits
 *	in @link->eh_context.
 *
 *	LOCKING:
 *	None.
 */
void ata_eh_done(struct ata_link *link, struct ata_device *dev,
		 unsigned int action)
{
	struct ata_eh_context *ehc = &link->eh_context;

	ata_eh_clear_action(link, dev, &ehc->i, action);
}

/**
 *	ata_err_string - convert err_mask to descriptive string
 *	@err_mask: error mask to convert to string
 *
 *	Convert @err_mask to descriptive string.  Errors are
 *	prioritized according to severity and only the most severe
 *	error is reported.
 *
 *	LOCKING:
 *	None.
 *
 *	RETURNS:
 *	Descriptive string for @err_mask
 */
static const char *ata_err_string(unsigned int err_mask)
{
	if (err_mask & AC_ERR_HOST_BUS)
		return "host bus error";
	if (err_mask & AC_ERR_ATA_BUS)
		return "ATA bus error";
	if (err_mask & AC_ERR_TIMEOUT)
		return "timeout";
	if (err_mask & AC_ERR_HSM)
		return "HSM violation";
	if (err_mask & AC_ERR_SYSTEM)
		return "internal error";
	if (err_mask & AC_ERR_MEDIA)
		return "media error";
	if (err_mask & AC_ERR_INVALID)
		return "invalid argument";
	if (err_mask & AC_ERR_DEV)
		return "device error";
	return "unknown error";
}

/**
 *	ata_read_log_page - read a specific log page
 *	@dev: target device
 *	@page: page to read
 *	@buf: buffer to store read page
 *	@sectors: number of sectors to read
 *
 *	Read log page using READ_LOG_EXT command.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, AC_ERR_* mask otherwise.
 */
static unsigned int ata_read_log_page(struct ata_device *dev,
				      u8 page, void *buf, unsigned int sectors)
{
	struct ata_taskfile tf;
	unsigned int err_mask;

	DPRINTK("read log page - page %d\n", page);

	ata_tf_init(dev, &tf);
	tf.command = ATA_CMD_READ_LOG_EXT;
	tf.lbal = page;
	tf.nsect = sectors;
	tf.hob_nsect = sectors >> 8;
	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_LBA48 | ATA_TFLAG_DEVICE;
	tf.protocol = ATA_PROT_PIO;

	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
				     buf, sectors * ATA_SECT_SIZE, 0);

	DPRINTK("EXIT, err_mask=%x\n", err_mask);
	return err_mask;
}

/**
 *	ata_eh_read_log_10h - Read log page 10h for NCQ error details
 *	@dev: Device to read log page 10h from
 *	@tag: Resulting tag of the failed command
 *	@tf: Resulting taskfile registers of the failed command
 *
 *	Read log page 10h to obtain NCQ error details and clear error
 *	condition.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno otherwise.
 */
static int ata_eh_read_log_10h(struct ata_device *dev,
			       int *tag, struct ata_taskfile *tf)
{
	u8 *buf = dev->link->ap->sector_buf;
	unsigned int err_mask;
	u8 csum;
	int i;

	err_mask = ata_read_log_page(dev, ATA_LOG_SATA_NCQ, buf, 1);
	if (err_mask)
		return -EIO;

	csum = 0;
	for (i = 0; i < ATA_SECT_SIZE; i++)
		csum += buf[i];
	if (csum)
		ata_dev_warn(dev, "invalid checksum 0x%x on log page 10h\n",
			     csum);

	if (buf[0] & 0x80)
		return -ENOENT;

	*tag = buf[0] & 0x1f;

	tf->command = buf[2];
	tf->feature = buf[3];
	tf->lbal = buf[4];
	tf->lbam = buf[5];
	tf->lbah = buf[6];
	tf->device = buf[7];
	tf->hob_lbal = buf[8];
	tf->hob_lbam = buf[9];
	tf->hob_lbah = buf[10];
	tf->nsect = buf[12];
	tf->hob_nsect = buf[13];

	return 0;
}

/**
 *	atapi_eh_tur - perform ATAPI TEST_UNIT_READY
 *	@dev: target ATAPI device
 *	@r_sense_key: out parameter for sense_key
 *
 *	Perform ATAPI TEST_UNIT_READY.
 *
 *	LOCKING:
 *	EH context (may sleep).
 *
 *	RETURNS:
 *	0 on success, AC_ERR_* mask on failure.
 */
static unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
{
	u8 cdb[ATAPI_CDB_LEN] = { TEST_UNIT_READY, 0, 0, 0, 0, 0 };
	struct ata_taskfile tf;
	unsigned int err_mask;

	ata_tf_init(dev, &tf);

	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	tf.command = ATA_CMD_PACKET;
	tf.protocol = ATAPI_PROT_NODATA;

	err_mask = ata_exec_internal(dev, &tf, cdb, DMA_NONE, NULL, 0, 0);
	if (err_mask == AC_ERR_DEV)
		*r_sense_key = tf.feature >> 4;
	return err_mask;
}

/**
 *	atapi_eh_request_sense - perform ATAPI REQUEST_SENSE
 *	@dev: device to perform REQUEST_SENSE to
 *	@sense_buf: result sense data buffer (SCSI_SENSE_BUFFERSIZE bytes long)
 *	@dfl_sense_key: default sense key to use
 *
 *	Perform ATAPI REQUEST_SENSE after the device reported CHECK
 *	SENSE.  This function is EH helper.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, AC_ERR_* mask on failure
 */
static unsigned int atapi_eh_request_sense(struct ata_device *dev,
					   u8 *sense_buf, u8 dfl_sense_key)
{
	u8 cdb[ATAPI_CDB_LEN] =
		{ REQUEST_SENSE, 0, 0, 0, SCSI_SENSE_BUFFERSIZE, 0 };
	struct ata_port *ap = dev->link->ap;
	struct ata_taskfile tf;

	DPRINTK("ATAPI request sense\n");

	/* FIXME: is this needed? */
	memset(sense_buf, 0, SCSI_SENSE_BUFFERSIZE);

	/* initialize sense_buf with the error register,
	 * for the case where they are -not- overwritten
	 */
	sense_buf[0] = 0x70;
	sense_buf[2] = dfl_sense_key;

	/* some devices time out if garbage left in tf */
	ata_tf_init(dev, &tf);

	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	tf.command = ATA_CMD_PACKET;

	/* is it pointless to prefer PIO for "safety reasons"? */
	if (ap->flags & ATA_FLAG_PIO_DMA) {
		tf.protocol = ATAPI_PROT_DMA;
		tf.feature |= ATAPI_PKT_DMA;
	} else {
		tf.protocol = ATAPI_PROT_PIO;
		tf.lbam = SCSI_SENSE_BUFFERSIZE;
		tf.lbah = 0;
	}

	return ata_exec_internal(dev, &tf, cdb, DMA_FROM_DEVICE,
				 sense_buf, SCSI_SENSE_BUFFERSIZE, 0);
}

/**
 *	ata_eh_analyze_serror - analyze SError for a failed port
 *	@link: ATA link to analyze SError for
 *
 *	Analyze SError if available and further determine cause of
 *	failure.
 *
 *	LOCKING:
 *	None.
 */
static void ata_eh_analyze_serror(struct ata_link *link)
{
	struct ata_eh_context *ehc = &link->eh_context;
	u32 serror = ehc->i.serror;
	unsigned int err_mask = 0, action = 0;
	u32 hotplug_mask;

	if (serror & (SERR_PERSISTENT | SERR_DATA)) {
		err_mask |= AC_ERR_ATA_BUS;
		action |= ATA_EH_RESET;
	}
	if (serror & SERR_PROTOCOL) {
		err_mask |= AC_ERR_HSM;
		action |= ATA_EH_RESET;
	}
	if (serror & SERR_INTERNAL) {
		err_mask |= AC_ERR_SYSTEM;
		action |= ATA_EH_RESET;
	}

	/* Determine whether a hotplug event has occurred.  Both
	 * SError.N/X are considered hotplug events for enabled or
	 * host links.  For disabled PMP links, only N bit is
	 * considered as X bit is left at 1 for link plugging.
	 */
	if (link->lpm_policy > ATA_LPM_MAX_POWER)
		hotplug_mask = 0;	/* hotplug doesn't work w/ LPM */
	else if (!(link->flags & ATA_LFLAG_DISABLED) || ata_is_host_link(link))
		hotplug_mask = SERR_PHYRDY_CHG | SERR_DEV_XCHG;
	else
		hotplug_mask = SERR_PHYRDY_CHG;

	if (serror & hotplug_mask)
		ata_ehi_hotplugged(&ehc->i);

	ehc->i.err_mask |= err_mask;
	ehc->i.action |= action;
}

/**
 *	ata_eh_analyze_ncq_error - analyze NCQ error
 *	@link: ATA link to analyze NCQ error for
 *
 *	Read log page 10h, determine the offending qc and acquire
 *	error status TF.  For NCQ device errors, all LLDDs have to do
 *	is setting AC_ERR_DEV in ehi->err_mask.  This function takes
 *	care of the rest.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
void ata_eh_analyze_ncq_error(struct ata_link *link)
{
	struct ata_port *ap = link->ap;
	struct ata_eh_context *ehc = &link->eh_context;
	struct ata_device *dev = link->device;
	struct ata_queued_cmd *qc;
	struct ata_taskfile tf;
	int tag, rc;

	/* if frozen, we can't do much */
	if (ap->pflags & ATA_PFLAG_FROZEN)
		return;

	/* is it NCQ device error? */
	if (!link->sactive || !(ehc->i.err_mask & AC_ERR_DEV))
		return;

	/* has LLDD analyzed already? */
	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
		qc = __ata_qc_from_tag(ap, tag);

		if (!(qc->flags & ATA_QCFLAG_FAILED))
			continue;

		if (qc->err_mask)
			return;
	}

	/* okay, this error is ours */
	memset(&tf, 0, sizeof(tf));
	rc = ata_eh_read_log_10h(dev, &tag, &tf);
	if (rc) {
		ata_link_err(link, "failed to read log page 10h (errno=%d)\n",
			     rc);
		return;
	}

	if (!(link->sactive & (1 << tag))) {
		ata_link_err(link, "log page 10h reported inactive tag %d\n",
			     tag);
		return;
	}

	/* we've got the perpetrator, condemn it */
	qc = __ata_qc_from_tag(ap, tag);
	memcpy(&qc->result_tf, &tf, sizeof(tf));
	qc->result_tf.flags = ATA_TFLAG_ISADDR | ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
	qc->err_mask |= AC_ERR_DEV | AC_ERR_NCQ;
	ehc->i.err_mask &= ~AC_ERR_DEV;
}

/**
 *	ata_eh_analyze_tf - analyze taskfile of a failed qc
 *	@qc: qc to analyze
 *	@tf: Taskfile registers to analyze
 *
 *	Analyze taskfile of @qc and further determine cause of
 *	failure.  This function also requests ATAPI sense data if
 *	available.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	Determined recovery action
 */
static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
				      const struct ata_taskfile *tf)
{
	unsigned int tmp, action = 0;
	u8 stat = tf->command, err = tf->feature;

	if ((stat & (ATA_BUSY | ATA_DRQ | ATA_DRDY)) != ATA_DRDY) {
		qc->err_mask |= AC_ERR_HSM;
		return ATA_EH_RESET;
	}

	if (stat & (ATA_ERR | ATA_DF))
		qc->err_mask |= AC_ERR_DEV;
	else
		return 0;

	switch (qc->dev->class) {
	case ATA_DEV_ATA:
		if (err & ATA_ICRC)
			qc->err_mask |= AC_ERR_ATA_BUS;
		if (err & ATA_UNC)
			qc->err_mask |= AC_ERR_MEDIA;
		if (err & ATA_IDNF)
			qc->err_mask |= AC_ERR_INVALID;
		break;

	case ATA_DEV_ATAPI:
		if (!(qc->ap->pflags & ATA_PFLAG_FROZEN)) {
			tmp = atapi_eh_request_sense(qc->dev,
						qc->scsicmd->sense_buffer,
						qc->result_tf.feature >> 4);
			if (!tmp) {
				/* ATA_QCFLAG_SENSE_VALID is used to
				 * tell atapi_qc_complete() that sense
				 * data is already valid.
				 *
				 * TODO: interpret sense data and set
				 * appropriate err_mask.
				 */
				qc->flags |= ATA_QCFLAG_SENSE_VALID;
			} else
				qc->err_mask |= tmp;
		}
	}

	if (qc->err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT | AC_ERR_ATA_BUS))
		action |= ATA_EH_RESET;

	return action;
}

static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask,
				   int *xfer_ok)
{
	int base = 0;

	if (!(eflags & ATA_EFLAG_DUBIOUS_XFER))
		*xfer_ok = 1;

	if (!*xfer_ok)
		base = ATA_ECAT_DUBIOUS_NONE;

	if (err_mask & AC_ERR_ATA_BUS)
		return base + ATA_ECAT_ATA_BUS;

	if (err_mask & AC_ERR_TIMEOUT)
		return base + ATA_ECAT_TOUT_HSM;

	if (eflags & ATA_EFLAG_IS_IO) {
		if (err_mask & AC_ERR_HSM)
			return base + ATA_ECAT_TOUT_HSM;
		if ((err_mask &
		     (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
			return base + ATA_ECAT_UNK_DEV;
	}

	return 0;
}

struct speed_down_verdict_arg {
	u64 since;
	int xfer_ok;
	int nr_errors[ATA_ECAT_NR];
};

static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
{
	struct speed_down_verdict_arg *arg = void_arg;
	int cat;

	if ((ent->eflags & ATA_EFLAG_OLD_ER) || (ent->timestamp < arg->since))
		return -1;

	cat = ata_eh_categorize_error(ent->eflags, ent->err_mask,
				      &arg->xfer_ok);
	arg->nr_errors[cat]++;

	return 0;
}

/**
 *	ata_eh_speed_down_verdict - Determine speed down verdict
 *	@dev: Device of interest
 *
 *	This function examines error ring of @dev and determines
 *	whether NCQ needs to be turned off, transfer speed should be
 *	stepped down, or falling back to PIO is necessary.
 *
 *	ECAT_ATA_BUS	: ATA_BUS error for any command
 *
 *	ECAT_TOUT_HSM	: TIMEOUT for any command or HSM violation for
 *			  IO commands
 *
 *	ECAT_UNK_DEV	: Unknown DEV error for IO commands
 *
 *	ECAT_DUBIOUS_*	: Identical to above three but occurred while
 *			  data transfer hasn't been verified.
 *
 *	Verdicts are
 *
 *	NCQ_OFF		: Turn off NCQ.
 *
 *	SPEED_DOWN	: Speed down transfer speed but don't fall back
 *			  to PIO.
 *
 *	FALLBACK_TO_PIO	: Fall back to PIO.
 *
 *	Even if multiple verdicts are returned, only one action is
 *	taken per error.  An action triggered by non-DUBIOUS errors
 *	clears ering, while one triggered by DUBIOUS_* errors doesn't.
 *	This is to expedite speed down decisions right after device is
 *	initially configured.
 *
 *	The followings are speed down rules.  #1 and #2 deal with
 *	DUBIOUS errors.
 *
 *	1. If more than one DUBIOUS_ATA_BUS or DUBIOUS_TOUT_HSM errors
 *	   occurred during last 5 mins, SPEED_DOWN and FALLBACK_TO_PIO.
 *
 *	2. If more than one DUBIOUS_TOUT_HSM or DUBIOUS_UNK_DEV errors
 *	   occurred during last 5 mins, NCQ_OFF.
 *
 *	3. If more than 8 ATA_BUS, TOUT_HSM or UNK_DEV errors
 *	   occurred during last 5 mins, FALLBACK_TO_PIO
 *
 *	4. If more than 3 TOUT_HSM or UNK_DEV errors occurred
 *	   during last 10 mins, NCQ_OFF.
 *
 *	5. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 6
 *	   UNK_DEV errors occurred during last 10 mins, SPEED_DOWN.
 *
 *	LOCKING:
 *	Inherited from caller.
 *
 *	RETURNS:
 *	OR of ATA_EH_SPDN_* flags.
 */
static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
{
	const u64 j5mins = 5LLU * 60 * HZ, j10mins = 10LLU * 60 * HZ;
	u64 j64 = get_jiffies_64();
	struct speed_down_verdict_arg arg;
	unsigned int verdict = 0;

	/* scan past 5 mins of error history */
	memset(&arg, 0, sizeof(arg));
	arg.since = j64 - min(j64, j5mins);
	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);

	if (arg.nr_errors[ATA_ECAT_DUBIOUS_ATA_BUS] +
	    arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] > 1)
		verdict |= ATA_EH_SPDN_SPEED_DOWN |
			ATA_EH_SPDN_FALLBACK_TO_PIO | ATA_EH_SPDN_KEEP_ERRORS;

	if (arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] +
	    arg.nr_errors[ATA_ECAT_DUBIOUS_UNK_DEV] > 1)
		verdict |= ATA_EH_SPDN_NCQ_OFF | ATA_EH_SPDN_KEEP_ERRORS;

	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
	    arg.nr_errors[ATA_ECAT_TOUT_HSM] +
	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;

	/* scan past 10 mins of error history */
	memset(&arg, 0, sizeof(arg));
	arg.since = j64 - min(j64, j10mins);
	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);

	if (arg.nr_errors[ATA_ECAT_TOUT_HSM] +
	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 3)
		verdict |= ATA_EH_SPDN_NCQ_OFF;

	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
	    arg.nr_errors[ATA_ECAT_TOUT_HSM] > 3 ||
	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
		verdict |= ATA_EH_SPDN_SPEED_DOWN;

	return verdict;
}

/**
 *	ata_eh_speed_down - record error and speed down if necessary
 *	@dev: Failed device
 *	@eflags: mask of ATA_EFLAG_* flags
 *	@err_mask: err_mask of the error
 *
 *	Record error and examine error history to determine whether
 *	adjusting transmission speed is necessary.  It also sets
 *	transmission limits appropriately if such adjustment is
 *	necessary.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	Determined recovery action.
 */
static unsigned int ata_eh_speed_down(struct ata_device *dev,
				unsigned int eflags, unsigned int err_mask)
{
	struct ata_link *link = ata_dev_phys_link(dev);
	int xfer_ok = 0;
	unsigned int verdict;
	unsigned int action = 0;

	/* don't bother if Cat-0 error */
	if (ata_eh_categorize_error(eflags, err_mask, &xfer_ok) == 0)
		return 0;

	/* record error and determine whether speed down is necessary */
	ata_ering_record(&dev->ering, eflags, err_mask);
	verdict = ata_eh_speed_down_verdict(dev);

	/* turn off NCQ? */
	if ((verdict & ATA_EH_SPDN_NCQ_OFF) &&
	    (dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ |
			   ATA_DFLAG_NCQ_OFF)) == ATA_DFLAG_NCQ) {
		dev->flags |= ATA_DFLAG_NCQ_OFF;
		ata_dev_warn(dev, "NCQ disabled due to excessive errors\n");
		goto done;
	}

	/* speed down? */
	if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
		/* speed down SATA link speed if possible */
		if (sata_down_spd_limit(link, 0) == 0) {
			action |= ATA_EH_RESET;
			goto done;
		}

		/* lower transfer mode */
		if (dev->spdn_cnt < 2) {
			static const int dma_dnxfer_sel[] =
				{ ATA_DNXFER_DMA, ATA_DNXFER_40C };
			static const int pio_dnxfer_sel[] =
				{ ATA_DNXFER_PIO, ATA_DNXFER_FORCE_PIO0 };
			int sel;

			if (dev->xfer_shift != ATA_SHIFT_PIO)
				sel = dma_dnxfer_sel[dev->spdn_cnt];
			else
				sel = pio_dnxfer_sel[dev->spdn_cnt];

			dev->spdn_cnt++;

			if (ata_down_xfermask_limit(dev, sel) == 0) {
				action |= ATA_EH_RESET;
				goto done;
			}
		}
	}

	/* Fall back to PIO?  Slowing down to PIO is meaningless for
	 * SATA ATA devices.  Consider it only for PATA and SATAPI.
	 */
	if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
	    (link->ap->cbl != ATA_CBL_SATA || dev->class == ATA_DEV_ATAPI) &&
	    (dev->xfer_shift != ATA_SHIFT_PIO)) {
		if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
			dev->spdn_cnt = 0;
			action |= ATA_EH_RESET;
			goto done;
		}
	}

	return 0;
 done:
	/* device has been slowed down, blow error history */
	if (!(verdict & ATA_EH_SPDN_KEEP_ERRORS))
		ata_ering_clear(&dev->ering);
	return action;
}

/**
 *	ata_eh_worth_retry - analyze error and decide whether to retry
 *	@qc: qc to possibly retry
 *
 *	Look at the cause of the error and decide if a retry
 * 	might be useful or not.  We don't want to retry media errors
 *	because the drive itself has probably already taken 10-30 seconds
 *	doing its own internal retries before reporting the failure.
 */
static inline int ata_eh_worth_retry(struct ata_queued_cmd *qc)
{
	if (qc->flags & AC_ERR_MEDIA)
		return 0;	/* don't retry media errors */
	if (qc->flags & ATA_QCFLAG_IO)
		return 1;	/* otherwise retry anything from fs stack */
	if (qc->err_mask & AC_ERR_INVALID)
		return 0;	/* don't retry these */
	return qc->err_mask != AC_ERR_DEV;  /* retry if not dev error */
}

/**
 *	ata_eh_link_autopsy - analyze error and determine recovery action
 *	@link: host link to perform autopsy on
 *
 *	Analyze why @link failed and determine which recovery actions
 *	are needed.  This function also sets more detailed AC_ERR_*
 *	values and fills sense data for ATAPI CHECK SENSE.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
static void ata_eh_link_autopsy(struct ata_link *link)
{
	struct ata_port *ap = link->ap;
	struct ata_eh_context *ehc = &link->eh_context;
	struct ata_device *dev;
	unsigned int all_err_mask = 0, eflags = 0;
	int tag;
	u32 serror;
	int rc;

	DPRINTK("ENTER\n");

	if (ehc->i.flags & ATA_EHI_NO_AUTOPSY)
		return;

	/* obtain and analyze SError */
	rc = sata_scr_read(link, SCR_ERROR, &serror);
	if (rc == 0) {
		ehc->i.serror |= serror;
		ata_eh_analyze_serror(link);
	} else if (rc != -EOPNOTSUPP) {
		/* SError read failed, force reset and probing */
		ehc->i.probe_mask |= ATA_ALL_DEVICES;
		ehc->i.action |= ATA_EH_RESET;
		ehc->i.err_mask |= AC_ERR_OTHER;
	}

	/* analyze NCQ failure */
	ata_eh_analyze_ncq_error(link);

	/* any real error trumps AC_ERR_OTHER */
	if (ehc->i.err_mask & ~AC_ERR_OTHER)
		ehc->i.err_mask &= ~AC_ERR_OTHER;

	all_err_mask |= ehc->i.err_mask;

	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);

		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
		    ata_dev_phys_link(qc->dev) != link)
			continue;

		/* inherit upper level err_mask */
		qc->err_mask |= ehc->i.err_mask;

		/* analyze TF */
		ehc->i.action |= ata_eh_analyze_tf(qc, &qc->result_tf);

		/* DEV errors are probably spurious in case of ATA_BUS error */
		if (qc->err_mask & AC_ERR_ATA_BUS)
			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_MEDIA |
					  AC_ERR_INVALID);

		/* any real error trumps unknown error */
		if (qc->err_mask & ~AC_ERR_OTHER)
			qc->err_mask &= ~AC_ERR_OTHER;

		/* SENSE_VALID trumps dev/unknown error and revalidation */
		if (qc->flags & ATA_QCFLAG_SENSE_VALID)
			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_OTHER);

		/* determine whether the command is worth retrying */
		if (ata_eh_worth_retry(qc))
			qc->flags |= ATA_QCFLAG_RETRY;

		/* accumulate error info */
		ehc->i.dev = qc->dev;
		all_err_mask |= qc->err_mask;
		if (qc->flags & ATA_QCFLAG_IO)
			eflags |= ATA_EFLAG_IS_IO;
	}

	/* enforce default EH actions */
	if (ap->pflags & ATA_PFLAG_FROZEN ||
	    all_err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT))
		ehc->i.action |= ATA_EH_RESET;
	else if (((eflags & ATA_EFLAG_IS_IO) && all_err_mask) ||
		 (!(eflags & ATA_EFLAG_IS_IO) && (all_err_mask & ~AC_ERR_DEV)))
		ehc->i.action |= ATA_EH_REVALIDATE;

	/* If we have offending qcs and the associated failed device,
	 * perform per-dev EH action only on the offending device.
	 */
	if (ehc->i.dev) {
		ehc->i.dev_action[ehc->i.dev->devno] |=
			ehc->i.action & ATA_EH_PERDEV_MASK;
		ehc->i.action &= ~ATA_EH_PERDEV_MASK;
	}

	/* propagate timeout to host link */
	if ((all_err_mask & AC_ERR_TIMEOUT) && !ata_is_host_link(link))
		ap->link.eh_context.i.err_mask |= AC_ERR_TIMEOUT;

	/* record error and consider speeding down */
	dev = ehc->i.dev;
	if (!dev && ((ata_link_max_devices(link) == 1 &&
		      ata_dev_enabled(link->device))))
	    dev = link->device;

	if (dev) {
		if (dev->flags & ATA_DFLAG_DUBIOUS_XFER)
			eflags |= ATA_EFLAG_DUBIOUS_XFER;
		ehc->i.action |= ata_eh_speed_down(dev, eflags, all_err_mask);
	}

	DPRINTK("EXIT\n");
}

/**
 *	ata_eh_autopsy - analyze error and determine recovery action
 *	@ap: host port to perform autopsy on
 *
 *	Analyze all links of @ap and determine why they failed and
 *	which recovery actions are needed.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
void ata_eh_autopsy(struct ata_port *ap)
{
	struct ata_link *link;

	ata_for_each_link(link, ap, EDGE)
		ata_eh_link_autopsy(link);

	/* Handle the frigging slave link.  Autopsy is done similarly
	 * but actions and flags are transferred over to the master
	 * link and handled from there.
	 */
	if (ap->slave_link) {
		struct ata_eh_context *mehc = &ap->link.eh_context;
		struct ata_eh_context *sehc = &ap->slave_link->eh_context;

		/* transfer control flags from master to slave */
		sehc->i.flags |= mehc->i.flags & ATA_EHI_TO_SLAVE_MASK;

		/* perform autopsy on the slave link */
		ata_eh_link_autopsy(ap->slave_link);

		/* transfer actions from slave to master and clear slave */
		ata_eh_about_to_do(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
		mehc->i.action		|= sehc->i.action;
		mehc->i.dev_action[1]	|= sehc->i.dev_action[1];
		mehc->i.flags		|= sehc->i.flags;
		ata_eh_done(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
	}

	/* Autopsy of fanout ports can affect host link autopsy.
	 * Perform host link autopsy last.
	 */
	if (sata_pmp_attached(ap))
		ata_eh_link_autopsy(&ap->link);
}

/**
 *	ata_get_cmd_descript - get description for ATA command
 *	@command: ATA command code to get description for
 *
 *	Return a textual description of the given command, or NULL if the
 *	command is not known.
 *
 *	LOCKING:
 *	None
 */
const char *ata_get_cmd_descript(u8 command)
{
#ifdef CONFIG_ATA_VERBOSE_ERROR
	static const struct
	{
		u8 command;
		const char *text;
	} cmd_descr[] = {
		{ ATA_CMD_DEV_RESET,		"DEVICE RESET" },
		{ ATA_CMD_CHK_POWER, 		"CHECK POWER MODE" },
		{ ATA_CMD_STANDBY, 		"STANDBY" },
		{ ATA_CMD_IDLE, 		"IDLE" },
		{ ATA_CMD_EDD, 			"EXECUTE DEVICE DIAGNOSTIC" },
		{ ATA_CMD_DOWNLOAD_MICRO,   	"DOWNLOAD MICROCODE" },
		{ ATA_CMD_NOP,			"NOP" },
		{ ATA_CMD_FLUSH, 		"FLUSH CACHE" },
		{ ATA_CMD_FLUSH_EXT, 		"FLUSH CACHE EXT" },
		{ ATA_CMD_ID_ATA,  		"IDENTIFY DEVICE" },
		{ ATA_CMD_ID_ATAPI, 		"IDENTIFY PACKET DEVICE" },
		{ ATA_CMD_SERVICE, 		"SERVICE" },
		{ ATA_CMD_READ, 		"READ DMA" },
		{ ATA_CMD_READ_EXT, 		"READ DMA EXT" },
		{ ATA_CMD_READ_QUEUED, 		"READ DMA QUEUED" },
		{ ATA_CMD_READ_STREAM_EXT, 	"READ STREAM EXT" },
		{ ATA_CMD_READ_STREAM_DMA_EXT,  "READ STREAM DMA EXT" },
		{ ATA_CMD_WRITE, 		"WRITE DMA" },
		{ ATA_CMD_WRITE_EXT, 		"WRITE DMA EXT" },
		{ ATA_CMD_WRITE_QUEUED, 	"WRITE DMA QUEUED EXT" },
		{ ATA_CMD_WRITE_STREAM_EXT, 	"WRITE STREAM EXT" },
		{ ATA_CMD_WRITE_STREAM_DMA_EXT, "WRITE STREAM DMA EXT" },
		{ ATA_CMD_WRITE_FUA_EXT,	"WRITE DMA FUA EXT" },
		{ ATA_CMD_WRITE_QUEUED_FUA_EXT, "WRITE DMA QUEUED FUA EXT" },
		{ ATA_CMD_FPDMA_READ,		"READ FPDMA QUEUED" },
		{ ATA_CMD_FPDMA_WRITE,		"WRITE FPDMA QUEUED" },
		{ ATA_CMD_PIO_READ,		"READ SECTOR(S)" },
		{ ATA_CMD_PIO_READ_EXT,		"READ SECTOR(S) EXT" },
		{ ATA_CMD_PIO_WRITE,		"WRITE SECTOR(S)" },
		{ ATA_CMD_PIO_WRITE_EXT,	"WRITE SECTOR(S) EXT" },
		{ ATA_CMD_READ_MULTI,		"READ MULTIPLE" },
		{ ATA_CMD_READ_MULTI_EXT,	"READ MULTIPLE EXT" },
		{ ATA_CMD_WRITE_MULTI,		"WRITE MULTIPLE" },
		{ ATA_CMD_WRITE_MULTI_EXT,	"WRITE MULTIPLE EXT" },
		{ ATA_CMD_WRITE_MULTI_FUA_EXT, 	"WRITE MULTIPLE FUA EXT" },
		{ ATA_CMD_SET_FEATURES,		"SET FEATURES" },
		{ ATA_CMD_SET_MULTI,		"SET MULTIPLE MODE" },
		{ ATA_CMD_VERIFY,		"READ VERIFY SECTOR(S)" },
		{ ATA_CMD_VERIFY_EXT,		"READ VERIFY SECTOR(S) EXT" },
		{ ATA_CMD_WRITE_UNCORR_EXT,	"WRITE UNCORRECTABLE EXT" },
		{ ATA_CMD_STANDBYNOW1,		"STANDBY IMMEDIATE" },
		{ ATA_CMD_IDLEIMMEDIATE,	"IDLE IMMEDIATE" },
		{ ATA_CMD_SLEEP,		"SLEEP" },
		{ ATA_CMD_INIT_DEV_PARAMS,	"INITIALIZE DEVICE PARAMETERS" },
		{ ATA_CMD_READ_NATIVE_MAX,	"READ NATIVE MAX ADDRESS" },
		{ ATA_CMD_READ_NATIVE_MAX_EXT,	"READ NATIVE MAX ADDRESS EXT" },
		{ ATA_CMD_SET_MAX,		"SET MAX ADDRESS" },
		{ ATA_CMD_SET_MAX_EXT,		"SET MAX ADDRESS EXT" },
		{ ATA_CMD_READ_LOG_EXT,		"READ LOG EXT" },
		{ ATA_CMD_WRITE_LOG_EXT,	"WRITE LOG EXT" },
		{ ATA_CMD_READ_LOG_DMA_EXT,	"READ LOG DMA EXT" },
		{ ATA_CMD_WRITE_LOG_DMA_EXT, 	"WRITE LOG DMA EXT" },
		{ ATA_CMD_TRUSTED_RCV,		"TRUSTED RECEIVE" },
		{ ATA_CMD_TRUSTED_RCV_DMA, 	"TRUSTED RECEIVE DMA" },
		{ ATA_CMD_TRUSTED_SND,		"TRUSTED SEND" },
		{ ATA_CMD_TRUSTED_SND_DMA, 	"TRUSTED SEND DMA" },
		{ ATA_CMD_PMP_READ,		"READ BUFFER" },
		{ ATA_CMD_PMP_WRITE,		"WRITE BUFFER" },
		{ ATA_CMD_CONF_OVERLAY,		"DEVICE CONFIGURATION OVERLAY" },
		{ ATA_CMD_SEC_SET_PASS,		"SECURITY SET PASSWORD" },
		{ ATA_CMD_SEC_UNLOCK,		"SECURITY UNLOCK" },
		{ ATA_CMD_SEC_ERASE_PREP,	"SECURITY ERASE PREPARE" },
		{ ATA_CMD_SEC_ERASE_UNIT,	"SECURITY ERASE UNIT" },
		{ ATA_CMD_SEC_FREEZE_LOCK,	"SECURITY FREEZE LOCK" },
		{ ATA_CMD_SEC_DISABLE_PASS,	"SECURITY DISABLE PASSWORD" },
		{ ATA_CMD_CONFIG_STREAM,	"CONFIGURE STREAM" },
		{ ATA_CMD_SMART,		"SMART" },
		{ ATA_CMD_MEDIA_LOCK,		"DOOR LOCK" },
		{ ATA_CMD_MEDIA_UNLOCK,		"DOOR UNLOCK" },
		{ ATA_CMD_DSM,			"DATA SET MANAGEMENT" },
		{ ATA_CMD_CHK_MED_CRD_TYP, 	"CHECK MEDIA CARD TYPE" },
		{ ATA_CMD_CFA_REQ_EXT_ERR, 	"CFA REQUEST EXTENDED ERROR" },
		{ ATA_CMD_CFA_WRITE_NE,		"CFA WRITE SECTORS WITHOUT ERASE" },
		{ ATA_CMD_CFA_TRANS_SECT,	"CFA TRANSLATE SECTOR" },
		{ ATA_CMD_CFA_ERASE,		"CFA ERASE SECTORS" },
		{ ATA_CMD_CFA_WRITE_MULT_NE, 	"CFA WRITE MULTIPLE WITHOUT ERASE" },
		{ ATA_CMD_READ_LONG,		"READ LONG (with retries)" },
		{ ATA_CMD_READ_LONG_ONCE,	"READ LONG (without retries)" },
		{ ATA_CMD_WRITE_LONG,		"WRITE LONG (with retries)" },
		{ ATA_CMD_WRITE_LONG_ONCE,	"WRITE LONG (without retries)" },
		{ ATA_CMD_RESTORE,		"RECALIBRATE" },
		{ 0,				NULL } /* terminate list */
	};

	unsigned int i;
	for (i = 0; cmd_descr[i].text; i++)
		if (cmd_descr[i].command == command)
			return cmd_descr[i].text;
#endif

	return NULL;
}

/**
 *	ata_eh_link_report - report error handling to user
 *	@link: ATA link EH is going on
 *
 *	Report EH to user.
 *
 *	LOCKING:
 *	None.
 */
static void ata_eh_link_report(struct ata_link *link)
{
	struct ata_port *ap = link->ap;
	struct ata_eh_context *ehc = &link->eh_context;
	const char *frozen, *desc;
	char tries_buf[6];
	int tag, nr_failed = 0;

	if (ehc->i.flags & ATA_EHI_QUIET)
		return;

	desc = NULL;
	if (ehc->i.desc[0] != '\0')
		desc = ehc->i.desc;

	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);

		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
		    ata_dev_phys_link(qc->dev) != link ||
		    ((qc->flags & ATA_QCFLAG_QUIET) &&
		     qc->err_mask == AC_ERR_DEV))
			continue;
		if (qc->flags & ATA_QCFLAG_SENSE_VALID && !qc->err_mask)
			continue;

		nr_failed++;
	}

	if (!nr_failed && !ehc->i.err_mask)
		return;

	frozen = "";
	if (ap->pflags & ATA_PFLAG_FROZEN)
		frozen = " frozen";

	memset(tries_buf, 0, sizeof(tries_buf));
	if (ap->eh_tries < ATA_EH_MAX_TRIES)
		snprintf(tries_buf, sizeof(tries_buf) - 1, " t%d",
			 ap->eh_tries);

	if (ehc->i.dev) {
		ata_dev_err(ehc->i.dev, "exception Emask 0x%x "
			    "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
			    ehc->i.err_mask, link->sactive, ehc->i.serror,
			    ehc->i.action, frozen, tries_buf);
		if (desc)
			ata_dev_err(ehc->i.dev, "%s\n", desc);
	} else {
		ata_link_err(link, "exception Emask 0x%x "
			     "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
			     ehc->i.err_mask, link->sactive, ehc->i.serror,
			     ehc->i.action, frozen, tries_buf);
		if (desc)
			ata_link_err(link, "%s\n", desc);
	}

#ifdef CONFIG_ATA_VERBOSE_ERROR
	if (ehc->i.serror)
		ata_link_err(link,
		  "SError: { %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s}\n",
		  ehc->i.serror & SERR_DATA_RECOVERED ? "RecovData " : "",
		  ehc->i.serror & SERR_COMM_RECOVERED ? "RecovComm " : "",
		  ehc->i.serror & SERR_DATA ? "UnrecovData " : "",
		  ehc->i.serror & SERR_PERSISTENT ? "Persist " : "",
		  ehc->i.serror & SERR_PROTOCOL ? "Proto " : "",
		  ehc->i.serror & SERR_INTERNAL ? "HostInt " : "",
		  ehc->i.serror & SERR_PHYRDY_CHG ? "PHYRdyChg " : "",
		  ehc->i.serror & SERR_PHY_INT_ERR ? "PHYInt " : "",
		  ehc->i.serror & SERR_COMM_WAKE ? "CommWake " : "",
		  ehc->i.serror & SERR_10B_8B_ERR ? "10B8B " : "",
		  ehc->i.serror & SERR_DISPARITY ? "Dispar " : "",
		  ehc->i.serror & SERR_CRC ? "BadCRC " : "",
		  ehc->i.serror & SERR_HANDSHAKE ? "Handshk " : "",
		  ehc->i.serror & SERR_LINK_SEQ_ERR ? "LinkSeq " : "",
		  ehc->i.serror & SERR_TRANS_ST_ERROR ? "TrStaTrns " : "",
		  ehc->i.serror & SERR_UNRECOG_FIS ? "UnrecFIS " : "",
		  ehc->i.serror & SERR_DEV_XCHG ? "DevExch " : "");
#endif

	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
		struct ata_taskfile *cmd = &qc->tf, *res = &qc->result_tf;
		const u8 *cdb = qc->cdb;
		char data_buf[20] = "";
		char cdb_buf[70] = "";

		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
		    ata_dev_phys_link(qc->dev) != link || !qc->err_mask)
			continue;

		if (qc->dma_dir != DMA_NONE) {
			static const char *dma_str[] = {
				[DMA_BIDIRECTIONAL]	= "bidi",
				[DMA_TO_DEVICE]		= "out",
				[DMA_FROM_DEVICE]	= "in",
			};
			static const char *prot_str[] = {
				[ATA_PROT_PIO]		= "pio",
				[ATA_PROT_DMA]		= "dma",
				[ATA_PROT_NCQ]		= "ncq",
				[ATAPI_PROT_PIO]	= "pio",
				[ATAPI_PROT_DMA]	= "dma",
			};

			snprintf(data_buf, sizeof(data_buf), " %s %u %s",
				 prot_str[qc->tf.protocol], qc->nbytes,
				 dma_str[qc->dma_dir]);
		}

		if (ata_is_atapi(qc->tf.protocol)) {
			if (qc->scsicmd)
				scsi_print_command(qc->scsicmd);
			else
				snprintf(cdb_buf, sizeof(cdb_buf),
				 "cdb %02x %02x %02x %02x %02x %02x %02x %02x  "
				 "%02x %02x %02x %02x %02x %02x %02x %02x\n         ",
				 cdb[0], cdb[1], cdb[2], cdb[3],
				 cdb[4], cdb[5], cdb[6], cdb[7],
				 cdb[8], cdb[9], cdb[10], cdb[11],
				 cdb[12], cdb[13], cdb[14], cdb[15]);
		} else {
			const char *descr = ata_get_cmd_descript(cmd->command);
			if (descr)
				ata_dev_err(qc->dev, "failed command: %s\n",
					    descr);
		}

		ata_dev_err(qc->dev,
			"cmd %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
			"tag %d%s\n         %s"
			"res %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
			"Emask 0x%x (%s)%s\n",
			cmd->command, cmd->feature, cmd->nsect,
			cmd->lbal, cmd->lbam, cmd->lbah,
			cmd->hob_feature, cmd->hob_nsect,
			cmd->hob_lbal, cmd->hob_lbam, cmd->hob_lbah,
			cmd->device, qc->tag, data_buf, cdb_buf,
			res->command, res->feature, res->nsect,
			res->lbal, res->lbam, res->lbah,
			res->hob_feature, res->hob_nsect,
			res->hob_lbal, res->hob_lbam, res->hob_lbah,
			res->device, qc->err_mask, ata_err_string(qc->err_mask),
			qc->err_mask & AC_ERR_NCQ ? " <F>" : "");

#ifdef CONFIG_ATA_VERBOSE_ERROR
		if (res->command & (ATA_BUSY | ATA_DRDY | ATA_DF | ATA_DRQ |
				    ATA_ERR)) {
			if (res->command & ATA_BUSY)
				ata_dev_err(qc->dev, "status: { Busy }\n");
			else
				ata_dev_err(qc->dev, "status: { %s%s%s%s}\n",
				  res->command & ATA_DRDY ? "DRDY " : "",
				  res->command & ATA_DF ? "DF " : "",
				  res->command & ATA_DRQ ? "DRQ " : "",
				  res->command & ATA_ERR ? "ERR " : "");
		}

		if (cmd->command != ATA_CMD_PACKET &&
		    (res->feature & (ATA_ICRC | ATA_UNC | ATA_IDNF |
				     ATA_ABORTED)))
			ata_dev_err(qc->dev, "error: { %s%s%s%s}\n",
			  res->feature & ATA_ICRC ? "ICRC " : "",
			  res->feature & ATA_UNC ? "UNC " : "",
			  res->feature & ATA_IDNF ? "IDNF " : "",
			  res->feature & ATA_ABORTED ? "ABRT " : "");
#endif
	}
}

/**
 *	ata_eh_report - report error handling to user
 *	@ap: ATA port to report EH about
 *
 *	Report EH to user.
 *
 *	LOCKING:
 *	None.
 */
void ata_eh_report(struct ata_port *ap)
{
	struct ata_link *link;

	ata_for_each_link(link, ap, HOST_FIRST)
		ata_eh_link_report(link);
}

static int ata_do_reset(struct ata_link *link, ata_reset_fn_t reset,
			unsigned int *classes, unsigned long deadline,
			bool clear_classes)
{
	struct ata_device *dev;

	if (clear_classes)
		ata_for_each_dev(dev, link, ALL)
			classes[dev->devno] = ATA_DEV_UNKNOWN;

	return reset(link, classes, deadline);
}

static int ata_eh_followup_srst_needed(struct ata_link *link, int rc)
{
	if ((link->flags & ATA_LFLAG_NO_SRST) || ata_link_offline(link))
		return 0;
	if (rc == -EAGAIN)
		return 1;
	if (sata_pmp_supported(link->ap) && ata_is_host_link(link))
		return 1;
	return 0;
}

int ata_eh_reset(struct ata_link *link, int classify,
		 ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
		 ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
{
	struct ata_port *ap = link->ap;
	struct ata_link *slave = ap->slave_link;
	struct ata_eh_context *ehc = &link->eh_context;
	struct ata_eh_context *sehc = slave ? &slave->eh_context : NULL;
	unsigned int *classes = ehc->classes;
	unsigned int lflags = link->flags;
	int verbose = !(ehc->i.flags & ATA_EHI_QUIET);
	int max_tries = 0, try = 0;
	struct ata_link *failed_link;
	struct ata_device *dev;
	unsigned long deadline, now;
	ata_reset_fn_t reset;
	unsigned long flags;
	u32 sstatus;
	int nr_unknown, rc;

	/*
	 * Prepare to reset
	 */
	while (ata_eh_reset_timeouts[max_tries] != ULONG_MAX)
		max_tries++;
	if (link->flags & ATA_LFLAG_NO_HRST)
		hardreset = NULL;
	if (link->flags & ATA_LFLAG_NO_SRST)
		softreset = NULL;

	/* make sure each reset attempt is at least COOL_DOWN apart */
	if (ehc->i.flags & ATA_EHI_DID_RESET) {
		now = jiffies;
		WARN_ON(time_after(ehc->last_reset, now));
		deadline = ata_deadline(ehc->last_reset,
					ATA_EH_RESET_COOL_DOWN);
		if (time_before(now, deadline))
			schedule_timeout_uninterruptible(deadline - now);
	}

	spin_lock_irqsave(ap->lock, flags);
	ap->pflags |= ATA_PFLAG_RESETTING;
	spin_unlock_irqrestore(ap->lock, flags);

	ata_eh_about_to_do(link, NULL, ATA_EH_RESET);

	ata_for_each_dev(dev, link, ALL) {
		/* If we issue an SRST then an ATA drive (not ATAPI)
		 * may change configuration and be in PIO0 timing. If
		 * we do a hard reset (or are coming from power on)
		 * this is true for ATA or ATAPI. Until we've set a
		 * suitable controller mode we should not touch the
		 * bus as we may be talking too fast.
		 */
		dev->pio_mode = XFER_PIO_0;

		/* If the controller has a pio mode setup function
		 * then use it to set the chipset to rights. Don't
		 * touch the DMA setup as that will be dealt with when
		 * configuring devices.
		 */
		if (ap->ops->set_piomode)
			ap->ops->set_piomode(ap, dev);
	}

	/* prefer hardreset */
	reset = NULL;
	ehc->i.action &= ~ATA_EH_RESET;
	if (hardreset) {
		reset = hardreset;
		ehc->i.action |= ATA_EH_HARDRESET;
	} else if (softreset) {
		reset = softreset;
		ehc->i.action |= ATA_EH_SOFTRESET;
	}

	if (prereset) {
		unsigned long deadline = ata_deadline(jiffies,
						      ATA_EH_PRERESET_TIMEOUT);

		if (slave) {
			sehc->i.action &= ~ATA_EH_RESET;
			sehc->i.action |= ehc->i.action;
		}

		rc = prereset(link, deadline);

		/* If present, do prereset on slave link too.  Reset
		 * is skipped iff both master and slave links report
		 * -ENOENT or clear ATA_EH_RESET.
		 */
		if (slave && (rc == 0 || rc == -ENOENT)) {
			int tmp;

			tmp = prereset(slave, deadline);
			if (tmp != -ENOENT)
				rc = tmp;

			ehc->i.action |= sehc->i.action;
		}

		if (rc) {
			if (rc == -ENOENT) {
				ata_link_dbg(link, "port disabled--ignoring\n");
				ehc->i.action &= ~ATA_EH_RESET;

				ata_for_each_dev(dev, link, ALL)
					classes[dev->devno] = ATA_DEV_NONE;

				rc = 0;
			} else
				ata_link_err(link,
					     "prereset failed (errno=%d)\n",
					     rc);
			goto out;
		}

		/* prereset() might have cleared ATA_EH_RESET.  If so,
		 * bang classes, thaw and return.
		 */
		if (reset && !(ehc->i.action & ATA_EH_RESET)) {
			ata_for_each_dev(dev, link, ALL)
				classes[dev->devno] = ATA_DEV_NONE;
			if ((ap->pflags & ATA_PFLAG_FROZEN) &&
			    ata_is_host_link(link))
				ata_eh_thaw_port(ap);
			rc = 0;
			goto out;
		}
	}

 retry:
	/*
	 * Perform reset
	 */
	if (ata_is_host_link(link))
		ata_eh_freeze_port(ap);

	deadline = ata_deadline(jiffies, ata_eh_reset_timeouts[try++]);

	if (reset) {
		if (verbose)
			ata_link_info(link, "%s resetting link\n",
				      reset == softreset ? "soft" : "hard");

		/* mark that this EH session started with reset */
		ehc->last_reset = jiffies;
		if (reset == hardreset)
			ehc->i.flags |= ATA_EHI_DID_HARDRESET;
		else
			ehc->i.flags |= ATA_EHI_DID_SOFTRESET;

		rc = ata_do_reset(link, reset, classes, deadline, true);
		if (rc && rc != -EAGAIN) {
			failed_link = link;
			goto fail;
		}

		/* hardreset slave link if existent */
		if (slave && reset == hardreset) {
			int tmp;

			if (verbose)
				ata_link_info(slave, "hard resetting link\n");

			ata_eh_about_to_do(slave, NULL, ATA_EH_RESET);
			tmp = ata_do_reset(slave, reset, classes, deadline,
					   false);
			switch (tmp) {
			case -EAGAIN:
				rc = -EAGAIN;
			case 0:
				break;
			default:
				failed_link = slave;
				rc = tmp;
				goto fail;
			}
		}

		/* perform follow-up SRST if necessary */
		if (reset == hardreset &&
		    ata_eh_followup_srst_needed(link, rc)) {
			reset = softreset;

			if (!reset) {
				ata_link_err(link,
	     "follow-up softreset required but no softreset available\n");
				failed_link = link;
				rc = -EINVAL;
				goto fail;
			}

			ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
			rc = ata_do_reset(link, reset, classes, deadline, true);
			if (rc) {
				failed_link = link;
				goto fail;
			}
		}
	} else {
		if (verbose)
			ata_link_info(link,
	"no reset method available, skipping reset\n");
		if (!(lflags & ATA_LFLAG_ASSUME_CLASS))
			lflags |= ATA_LFLAG_ASSUME_ATA;
	}

	/*
	 * Post-reset processing
	 */
	ata_for_each_dev(dev, link, ALL) {
		/* After the reset, the device state is PIO 0 and the
		 * controller state is undefined.  Reset also wakes up
		 * drives from sleeping mode.
		 */
		dev->pio_mode = XFER_PIO_0;
		dev->flags &= ~ATA_DFLAG_SLEEPING;

		if (ata_phys_link_offline(ata_dev_phys_link(dev)))
			continue;

		/* apply class override */
		if (lflags & ATA_LFLAG_ASSUME_ATA)
			classes[dev->devno] = ATA_DEV_ATA;
		else if (lflags & ATA_LFLAG_ASSUME_SEMB)
			classes[dev->devno] = ATA_DEV_SEMB_UNSUP;
	}

	/* record current link speed */
	if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0)
		link->sata_spd = (sstatus >> 4) & 0xf;
	if (slave && sata_scr_read(slave, SCR_STATUS, &sstatus) == 0)
		slave->sata_spd = (sstatus >> 4) & 0xf;

	/* thaw the port */
	if (ata_is_host_link(link))
		ata_eh_thaw_port(ap);

	/* postreset() should clear hardware SError.  Although SError
	 * is cleared during link resume, clearing SError here is
	 * necessary as some PHYs raise hotplug events after SRST.
	 * This introduces race condition where hotplug occurs between
	 * reset and here.  This race is mediated by cross checking
	 * link onlineness and classification result later.
	 */
	if (postreset) {
		postreset(link, classes);
		if (slave)
			postreset(slave, classes);
	}

	/*
	 * Some controllers can't be frozen very well and may set spurious
	 * error conditions during reset.  Clear accumulated error
	 * information and re-thaw the port if frozen.  As reset is the
	 * final recovery action and we cross check link onlineness against
	 * device classification later, no hotplug event is lost by this.
	 */
	spin_lock_irqsave(link->ap->lock, flags);
	memset(&link->eh_info, 0, sizeof(link->eh_info));
	if (slave)
		memset(&slave->eh_info, 0, sizeof(link->eh_info));
	ap->pflags &= ~ATA_PFLAG_EH_PENDING;
	spin_unlock_irqrestore(link->ap->lock, flags);

	if (ap->pflags & ATA_PFLAG_FROZEN)
		ata_eh_thaw_port(ap);

	/*
	 * Make sure onlineness and classification result correspond.
	 * Hotplug could have happened during reset and some
	 * controllers fail to wait while a drive is spinning up after
	 * being hotplugged causing misdetection.  By cross checking
	 * link on/offlineness and classification result, those
	 * conditions can be reliably detected and retried.
	 */
	nr_unknown = 0;
	ata_for_each_dev(dev, link, ALL) {
		if (ata_phys_link_online(ata_dev_phys_link(dev))) {
			if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
				ata_dev_dbg(dev, "link online but device misclassified\n");
				classes[dev->devno] = ATA_DEV_NONE;
				nr_unknown++;
			}
		} else if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
			if (ata_class_enabled(classes[dev->devno]))
				ata_dev_dbg(dev,
					    "link offline, clearing class %d to NONE\n",
					    classes[dev->devno]);
			classes[dev->devno] = ATA_DEV_NONE;
		} else if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
			ata_dev_dbg(dev,
				    "link status unknown, clearing UNKNOWN to NONE\n");
			classes[dev->devno] = ATA_DEV_NONE;
		}
	}

	if (classify && nr_unknown) {
		if (try < max_tries) {
			ata_link_warn(link,
				      "link online but %d devices misclassified, retrying\n",
				      nr_unknown);
			failed_link = link;
			rc = -EAGAIN;
			goto fail;
		}
		ata_link_warn(link,
			      "link online but %d devices misclassified, "
			      "device detection might fail\n", nr_unknown);
	}

	/* reset successful, schedule revalidation */
	ata_eh_done(link, NULL, ATA_EH_RESET);
	if (slave)
		ata_eh_done(slave, NULL, ATA_EH_RESET);
	ehc->last_reset = jiffies;		/* update to completion time */
	ehc->i.action |= ATA_EH_REVALIDATE;
	link->lpm_policy = ATA_LPM_UNKNOWN;	/* reset LPM state */

	rc = 0;
 out:
	/* clear hotplug flag */
	ehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
	if (slave)
		sehc->i.flags &= ~ATA_EHI_HOTPLUGGED;

	spin_lock_irqsave(ap->lock, flags);
	ap->pflags &= ~ATA_PFLAG_RESETTING;
	spin_unlock_irqrestore(ap->lock, flags);

	return rc;

 fail:
	/* if SCR isn't accessible on a fan-out port, PMP needs to be reset */
	if (!ata_is_host_link(link) &&
	    sata_scr_read(link, SCR_STATUS, &sstatus))
		rc = -ERESTART;

	if (try >= max_tries) {
		/*
		 * Thaw host port even if reset failed, so that the port
		 * can be retried on the next phy event.  This risks
		 * repeated EH runs but seems to be a better tradeoff than
		 * shutting down a port after a botched hotplug attempt.
		 */
		if (ata_is_host_link(link))
			ata_eh_thaw_port(ap);
		goto out;
	}

	now = jiffies;
	if (time_before(now, deadline)) {
		unsigned long delta = deadline - now;

		ata_link_warn(failed_link,
			"reset failed (errno=%d), retrying in %u secs\n",
			rc, DIV_ROUND_UP(jiffies_to_msecs(delta), 1000));

		ata_eh_release(ap);
		while (delta)
			delta = schedule_timeout_uninterruptible(delta);
		ata_eh_acquire(ap);
	}

	/*
	 * While disks spinup behind PMP, some controllers fail sending SRST.
	 * They need to be reset - as well as the PMP - before retrying.
	 */
	if (rc == -ERESTART) {
		if (ata_is_host_link(link))
			ata_eh_thaw_port(ap);
		goto out;
	}

	if (try == max_tries - 1) {
		sata_down_spd_limit(link, 0);
		if (slave)
			sata_down_spd_limit(slave, 0);
	} else if (rc == -EPIPE)
		sata_down_spd_limit(failed_link, 0);

	if (hardreset)
		reset = hardreset;
	goto retry;
}

static inline void ata_eh_pull_park_action(struct ata_port *ap)
{
	struct ata_link *link;
	struct ata_device *dev;
	unsigned long flags;

	/*
	 * This function can be thought of as an extended version of
	 * ata_eh_about_to_do() specially crafted to accommodate the
	 * requirements of ATA_EH_PARK handling. Since the EH thread
	 * does not leave the do {} while () loop in ata_eh_recover as
	 * long as the timeout for a park request to *one* device on
	 * the port has not expired, and since we still want to pick
	 * up park requests to other devices on the same port or
	 * timeout updates for the same device, we have to pull
	 * ATA_EH_PARK actions from eh_info into eh_context.i
	 * ourselves at the beginning of each pass over the loop.
	 *
	 * Additionally, all write accesses to &ap->park_req_pending
	 * through INIT_COMPLETION() (see below) or complete_all()
	 * (see ata_scsi_park_store()) are protected by the host lock.
	 * As a result we have that park_req_pending.done is zero on
	 * exit from this function, i.e. when ATA_EH_PARK actions for
	 * *all* devices on port ap have been pulled into the
	 * respective eh_context structs. If, and only if,
	 * park_req_pending.done is non-zero by the time we reach
	 * wait_for_completion_timeout(), another ATA_EH_PARK action
	 * has been scheduled for at least one of the devices on port
	 * ap and we have to cycle over the do {} while () loop in
	 * ata_eh_recover() again.
	 */

	spin_lock_irqsave(ap->lock, flags);
	INIT_COMPLETION(ap->park_req_pending);
	ata_for_each_link(link, ap, EDGE) {
		ata_for_each_dev(dev, link, ALL) {
			struct ata_eh_info *ehi = &link->eh_info;

			link->eh_context.i.dev_action[dev->devno] |=
				ehi->dev_action[dev->devno] & ATA_EH_PARK;
			ata_eh_clear_action(link, dev, ehi, ATA_EH_PARK);
		}
	}
	spin_unlock_irqrestore(ap->lock, flags);
}

static void ata_eh_park_issue_cmd(struct ata_device *dev, int park)
{
	struct ata_eh_context *ehc = &dev->link->eh_context;
	struct ata_taskfile tf;
	unsigned int err_mask;

	ata_tf_init(dev, &tf);
	if (park) {
		ehc->unloaded_mask |= 1 << dev->devno;
		tf.command = ATA_CMD_IDLEIMMEDIATE;
		tf.feature = 0x44;
		tf.lbal = 0x4c;
		tf.lbam = 0x4e;
		tf.lbah = 0x55;
	} else {
		ehc->unloaded_mask &= ~(1 << dev->devno);
		tf.command = ATA_CMD_CHK_POWER;
	}

	tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
	tf.protocol |= ATA_PROT_NODATA;
	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
	if (park && (err_mask || tf.lbal != 0xc4)) {
		ata_dev_err(dev, "head unload failed!\n");
		ehc->unloaded_mask &= ~(1 << dev->devno);
	}
}

static int ata_eh_revalidate_and_attach(struct ata_link *link,
					struct ata_device **r_failed_dev)
{
	struct ata_port *ap = link->ap;
	struct ata_eh_context *ehc = &link->eh_context;
	struct ata_device *dev;
	unsigned int new_mask = 0;
	unsigned long flags;
	int rc = 0;

	DPRINTK("ENTER\n");

	/* For PATA drive side cable detection to work, IDENTIFY must
	 * be done backwards such that PDIAG- is released by the slave
	 * device before the master device is identified.
	 */
	ata_for_each_dev(dev, link, ALL_REVERSE) {
		unsigned int action = ata_eh_dev_action(dev);
		unsigned int readid_flags = 0;

		if (ehc->i.flags & ATA_EHI_DID_RESET)
			readid_flags |= ATA_READID_POSTRESET;

		if ((action & ATA_EH_REVALIDATE) && ata_dev_enabled(dev)) {
			WARN_ON(dev->class == ATA_DEV_PMP);

			if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
				rc = -EIO;
				goto err;
			}

			ata_eh_about_to_do(link, dev, ATA_EH_REVALIDATE);
			rc = ata_dev_revalidate(dev, ehc->classes[dev->devno],
						readid_flags);
			if (rc)
				goto err;

			ata_eh_done(link, dev, ATA_EH_REVALIDATE);

			/* Configuration may have changed, reconfigure
			 * transfer mode.
			 */
			ehc->i.flags |= ATA_EHI_SETMODE;

			/* schedule the scsi_rescan_device() here */
			schedule_work(&(ap->scsi_rescan_task));
		} else if (dev->class == ATA_DEV_UNKNOWN &&
			   ehc->tries[dev->devno] &&
			   ata_class_enabled(ehc->classes[dev->devno])) {
			/* Temporarily set dev->class, it will be
			 * permanently set once all configurations are
			 * complete.  This is necessary because new
			 * device configuration is done in two
			 * separate loops.
			 */
			dev->class = ehc->classes[dev->devno];

			if (dev->class == ATA_DEV_PMP)
				rc = sata_pmp_attach(dev);
			else
				rc = ata_dev_read_id(dev, &dev->class,
						     readid_flags, dev->id);

			/* read_id might have changed class, store and reset */
			ehc->classes[dev->devno] = dev->class;
			dev->class = ATA_DEV_UNKNOWN;

			switch (rc) {
			case 0:
				/* clear error info accumulated during probe */
				ata_ering_clear(&dev->ering);
				new_mask |= 1 << dev->devno;
				break;
			case -ENOENT:
				/* IDENTIFY was issued to non-existent
				 * device.  No need to reset.  Just
				 * thaw and ignore the device.
				 */
				ata_eh_thaw_port(ap);
				break;
			default:
				goto err;
			}
		}
	}

	/* PDIAG- should have been released, ask cable type if post-reset */
	if ((ehc->i.flags & ATA_EHI_DID_RESET) && ata_is_host_link(link)) {
		if (ap->ops->cable_detect)
			ap->cbl = ap->ops->cable_detect(ap);
		ata_force_cbl(ap);
	}

	/* Configure new devices forward such that user doesn't see
	 * device detection messages backwards.
	 */
	ata_for_each_dev(dev, link, ALL) {
		if (!(new_mask & (1 << dev->devno)))
			continue;

		dev->class = ehc->classes[dev->devno];

		if (dev->class == ATA_DEV_PMP)
			continue;

		ehc->i.flags |= ATA_EHI_PRINTINFO;
		rc = ata_dev_configure(dev);
		ehc->i.flags &= ~ATA_EHI_PRINTINFO;
		if (rc) {
			dev->class = ATA_DEV_UNKNOWN;
			goto err;
		}

		spin_lock_irqsave(ap->lock, flags);
		ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
		spin_unlock_irqrestore(ap->lock, flags);

		/* new device discovered, configure xfermode */
		ehc->i.flags |= ATA_EHI_SETMODE;
	}

	return 0;

 err:
	*r_failed_dev = dev;
	DPRINTK("EXIT rc=%d\n", rc);
	return rc;
}

/**
 *	ata_set_mode - Program timings and issue SET FEATURES - XFER
 *	@link: link on which timings will be programmed
 *	@r_failed_dev: out parameter for failed device
 *
 *	Set ATA device disk transfer mode (PIO3, UDMA6, etc.).  If
 *	ata_set_mode() fails, pointer to the failing device is
 *	returned in @r_failed_dev.
 *
 *	LOCKING:
 *	PCI/etc. bus probe sem.
 *
 *	RETURNS:
 *	0 on success, negative errno otherwise
 */
int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
{
	struct ata_port *ap = link->ap;
	struct ata_device *dev;
	int rc;

	/* if data transfer is verified, clear DUBIOUS_XFER on ering top */
	ata_for_each_dev(dev, link, ENABLED) {
		if (!(dev->flags & ATA_DFLAG_DUBIOUS_XFER)) {
			struct ata_ering_entry *ent;

			ent = ata_ering_top(&dev->ering);
			if (ent)
				ent->eflags &= ~ATA_EFLAG_DUBIOUS_XFER;
		}
	}

	/* has private set_mode? */
	if (ap->ops->set_mode)
		rc = ap->ops->set_mode(link, r_failed_dev);
	else
		rc = ata_do_set_mode(link, r_failed_dev);

	/* if transfer mode has changed, set DUBIOUS_XFER on device */
	ata_for_each_dev(dev, link, ENABLED) {
		struct ata_eh_context *ehc = &link->eh_context;
		u8 saved_xfer_mode = ehc->saved_xfer_mode[dev->devno];
		u8 saved_ncq = !!(ehc->saved_ncq_enabled & (1 << dev->devno));

		if (dev->xfer_mode != saved_xfer_mode ||
		    ata_ncq_enabled(dev) != saved_ncq)
			dev->flags |= ATA_DFLAG_DUBIOUS_XFER;
	}

	return rc;
}

/**
 *	atapi_eh_clear_ua - Clear ATAPI UNIT ATTENTION after reset
 *	@dev: ATAPI device to clear UA for
 *
 *	Resets and other operations can make an ATAPI device raise
 *	UNIT ATTENTION which causes the next operation to fail.  This
 *	function clears UA.
 *
 *	LOCKING:
 *	EH context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int atapi_eh_clear_ua(struct ata_device *dev)
{
	int i;

	for (i = 0; i < ATA_EH_UA_TRIES; i++) {
		u8 *sense_buffer = dev->link->ap->sector_buf;
		u8 sense_key = 0;
		unsigned int err_mask;

		err_mask = atapi_eh_tur(dev, &sense_key);
		if (err_mask != 0 && err_mask != AC_ERR_DEV) {
			ata_dev_warn(dev,
				     "TEST_UNIT_READY failed (err_mask=0x%x)\n",
				     err_mask);
			return -EIO;
		}

		if (!err_mask || sense_key != UNIT_ATTENTION)
			return 0;

		err_mask = atapi_eh_request_sense(dev, sense_buffer, sense_key);
		if (err_mask) {
			ata_dev_warn(dev, "failed to clear "
				"UNIT ATTENTION (err_mask=0x%x)\n", err_mask);
			return -EIO;
		}
	}

	ata_dev_warn(dev, "UNIT ATTENTION persists after %d tries\n",
		     ATA_EH_UA_TRIES);

	return 0;
}

/**
 *	ata_eh_maybe_retry_flush - Retry FLUSH if necessary
 *	@dev: ATA device which may need FLUSH retry
 *
 *	If @dev failed FLUSH, it needs to be reported upper layer
 *	immediately as it means that @dev failed to remap and already
 *	lost at least a sector and further FLUSH retrials won't make
 *	any difference to the lost sector.  However, if FLUSH failed
 *	for other reasons, for example transmission error, FLUSH needs
 *	to be retried.
 *
 *	This function determines whether FLUSH failure retry is
 *	necessary and performs it if so.
 *
 *	RETURNS:
 *	0 if EH can continue, -errno if EH needs to be repeated.
 */
static int ata_eh_maybe_retry_flush(struct ata_device *dev)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	struct ata_queued_cmd *qc;
	struct ata_taskfile tf;
	unsigned int err_mask;
	int rc = 0;

	/* did flush fail for this device? */
	if (!ata_tag_valid(link->active_tag))
		return 0;

	qc = __ata_qc_from_tag(ap, link->active_tag);
	if (qc->dev != dev || (qc->tf.command != ATA_CMD_FLUSH_EXT &&
			       qc->tf.command != ATA_CMD_FLUSH))
		return 0;

	/* if the device failed it, it should be reported to upper layers */
	if (qc->err_mask & AC_ERR_DEV)
		return 0;

	/* flush failed for some other reason, give it another shot */
	ata_tf_init(dev, &tf);

	tf.command = qc->tf.command;
	tf.flags |= ATA_TFLAG_DEVICE;
	tf.protocol = ATA_PROT_NODATA;

	ata_dev_warn(dev, "retrying FLUSH 0x%x Emask 0x%x\n",
		       tf.command, qc->err_mask);

	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
	if (!err_mask) {
		/*
		 * FLUSH is complete but there's no way to
		 * successfully complete a failed command from EH.
		 * Making sure retry is allowed at least once and
		 * retrying it should do the trick - whatever was in
		 * the cache is already on the platter and this won't
		 * cause infinite loop.
		 */
		qc->scsicmd->allowed = max(qc->scsicmd->allowed, 1);
	} else {
		ata_dev_warn(dev, "FLUSH failed Emask 0x%x\n",
			       err_mask);
		rc = -EIO;

		/* if device failed it, report it to upper layers */
		if (err_mask & AC_ERR_DEV) {
			qc->err_mask |= AC_ERR_DEV;
			qc->result_tf = tf;
			if (!(ap->pflags & ATA_PFLAG_FROZEN))
				rc = 0;
		}
	}
	return rc;
}

/**
 *	ata_eh_set_lpm - configure SATA interface power management
 *	@link: link to configure power management
 *	@policy: the link power management policy
 *	@r_failed_dev: out parameter for failed device
 *
 *	Enable SATA Interface power management.  This will enable
 *	Device Interface Power Management (DIPM) for min_power
 * 	policy, and then call driver specific callbacks for
 *	enabling Host Initiated Power management.
 *
 *	LOCKING:
 *	EH context.
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
			  struct ata_device **r_failed_dev)
{
	struct ata_port *ap = ata_is_host_link(link) ? link->ap : NULL;
	struct ata_eh_context *ehc = &link->eh_context;
	struct ata_device *dev, *link_dev = NULL, *lpm_dev = NULL;
	enum ata_lpm_policy old_policy = link->lpm_policy;
	bool no_dipm = link->ap->flags & ATA_FLAG_NO_DIPM;
	unsigned int hints = ATA_LPM_EMPTY | ATA_LPM_HIPM;
	unsigned int err_mask;
	int rc;

	/* if the link or host doesn't do LPM, noop */
	if ((link->flags & ATA_LFLAG_NO_LPM) || (ap && !ap->ops->set_lpm))
		return 0;

	/*
	 * DIPM is enabled only for MIN_POWER as some devices
	 * misbehave when the host NACKs transition to SLUMBER.  Order
	 * device and link configurations such that the host always
	 * allows DIPM requests.
	 */
	ata_for_each_dev(dev, link, ENABLED) {
		bool hipm = ata_id_has_hipm(dev->id);
		bool dipm = ata_id_has_dipm(dev->id) && !no_dipm;

		/* find the first enabled and LPM enabled devices */
		if (!link_dev)
			link_dev = dev;

		if (!lpm_dev && (hipm || dipm))
			lpm_dev = dev;

		hints &= ~ATA_LPM_EMPTY;
		if (!hipm)
			hints &= ~ATA_LPM_HIPM;

		/* disable DIPM before changing link config */
		if (policy != ATA_LPM_MIN_POWER && dipm) {
			err_mask = ata_dev_set_feature(dev,
					SETFEATURES_SATA_DISABLE, SATA_DIPM);
			if (err_mask && err_mask != AC_ERR_DEV) {
				ata_dev_warn(dev,
					     "failed to disable DIPM, Emask 0x%x\n",
					     err_mask);
				rc = -EIO;
				goto fail;
			}
		}
	}

	if (ap) {
		rc = ap->ops->set_lpm(link, policy, hints);
		if (!rc && ap->slave_link)
			rc = ap->ops->set_lpm(ap->slave_link, policy, hints);
	} else
		rc = sata_pmp_set_lpm(link, policy, hints);

	/*
	 * Attribute link config failure to the first (LPM) enabled
	 * device on the link.
	 */
	if (rc) {
		if (rc == -EOPNOTSUPP) {
			link->flags |= ATA_LFLAG_NO_LPM;
			return 0;
		}
		dev = lpm_dev ? lpm_dev : link_dev;
		goto fail;
	}

	/*
	 * Low level driver acked the transition.  Issue DIPM command
	 * with the new policy set.
	 */
	link->lpm_policy = policy;
	if (ap && ap->slave_link)
		ap->slave_link->lpm_policy = policy;

	/* host config updated, enable DIPM if transitioning to MIN_POWER */
	ata_for_each_dev(dev, link, ENABLED) {
		if (policy == ATA_LPM_MIN_POWER && !no_dipm &&
		    ata_id_has_dipm(dev->id)) {
			err_mask = ata_dev_set_feature(dev,
					SETFEATURES_SATA_ENABLE, SATA_DIPM);
			if (err_mask && err_mask != AC_ERR_DEV) {
				ata_dev_warn(dev,
					"failed to enable DIPM, Emask 0x%x\n",
					err_mask);
				rc = -EIO;
				goto fail;
			}
		}
	}

	return 0;

fail:
	/* restore the old policy */
	link->lpm_policy = old_policy;
	if (ap && ap->slave_link)
		ap->slave_link->lpm_policy = old_policy;

	/* if no device or only one more chance is left, disable LPM */
	if (!dev || ehc->tries[dev->devno] <= 2) {
		ata_link_warn(link, "disabling LPM on the link\n");
		link->flags |= ATA_LFLAG_NO_LPM;
	}
	if (r_failed_dev)
		*r_failed_dev = dev;
	return rc;
}

int ata_link_nr_enabled(struct ata_link *link)
{
	struct ata_device *dev;
	int cnt = 0;

	ata_for_each_dev(dev, link, ENABLED)
		cnt++;
	return cnt;
}

static int ata_link_nr_vacant(struct ata_link *link)
{
	struct ata_device *dev;
	int cnt = 0;

	ata_for_each_dev(dev, link, ALL)
		if (dev->class == ATA_DEV_UNKNOWN)
			cnt++;
	return cnt;
}

static int ata_eh_skip_recovery(struct ata_link *link)
{
	struct ata_port *ap = link->ap;
	struct ata_eh_context *ehc = &link->eh_context;
	struct ata_device *dev;

	/* skip disabled links */
	if (link->flags & ATA_LFLAG_DISABLED)
		return 1;

	/* skip if explicitly requested */
	if (ehc->i.flags & ATA_EHI_NO_RECOVERY)
		return 1;

	/* thaw frozen port and recover failed devices */
	if ((ap->pflags & ATA_PFLAG_FROZEN) || ata_link_nr_enabled(link))
		return 0;

	/* reset at least once if reset is requested */
	if ((ehc->i.action & ATA_EH_RESET) &&
	    !(ehc->i.flags & ATA_EHI_DID_RESET))
		return 0;

	/* skip if class codes for all vacant slots are ATA_DEV_NONE */
	ata_for_each_dev(dev, link, ALL) {
		if (dev->class == ATA_DEV_UNKNOWN &&
		    ehc->classes[dev->devno] != ATA_DEV_NONE)
			return 0;
	}

	return 1;
}

static int ata_count_probe_trials_cb(struct ata_ering_entry *ent, void *void_arg)
{
	u64 interval = msecs_to_jiffies(ATA_EH_PROBE_TRIAL_INTERVAL);
	u64 now = get_jiffies_64();
	int *trials = void_arg;

	if ((ent->eflags & ATA_EFLAG_OLD_ER) ||
	    (ent->timestamp < now - min(now, interval)))
		return -1;

	(*trials)++;
	return 0;
}

static int ata_eh_schedule_probe(struct ata_device *dev)
{
	struct ata_eh_context *ehc = &dev->link->eh_context;
	struct ata_link *link = ata_dev_phys_link(dev);
	int trials = 0;

	if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
	    (ehc->did_probe_mask & (1 << dev->devno)))
		return 0;

	ata_eh_detach_dev(dev);
	ata_dev_init(dev);
	ehc->did_probe_mask |= (1 << dev->devno);
	ehc->i.action |= ATA_EH_RESET;
	ehc->saved_xfer_mode[dev->devno] = 0;
	ehc->saved_ncq_enabled &= ~(1 << dev->devno);

	/* the link maybe in a deep sleep, wake it up */
	if (link->lpm_policy > ATA_LPM_MAX_POWER) {
		if (ata_is_host_link(link))
			link->ap->ops->set_lpm(link, ATA_LPM_MAX_POWER,
					       ATA_LPM_EMPTY);
		else
			sata_pmp_set_lpm(link, ATA_LPM_MAX_POWER,
					 ATA_LPM_EMPTY);
	}

	/* Record and count probe trials on the ering.  The specific
	 * error mask used is irrelevant.  Because a successful device
	 * detection clears the ering, this count accumulates only if
	 * there are consecutive failed probes.
	 *
	 * If the count is equal to or higher than ATA_EH_PROBE_TRIALS
	 * in the last ATA_EH_PROBE_TRIAL_INTERVAL, link speed is
	 * forced to 1.5Gbps.
	 *
	 * This is to work around cases where failed link speed
	 * negotiation results in device misdetection leading to
	 * infinite DEVXCHG or PHRDY CHG events.
	 */
	ata_ering_record(&dev->ering, 0, AC_ERR_OTHER);
	ata_ering_map(&dev->ering, ata_count_probe_trials_cb, &trials);

	if (trials > ATA_EH_PROBE_TRIALS)
		sata_down_spd_limit(link, 1);

	return 1;
}

static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
{
	struct ata_eh_context *ehc = &dev->link->eh_context;

	/* -EAGAIN from EH routine indicates retry without prejudice.
	 * The requester is responsible for ensuring forward progress.
	 */
	if (err != -EAGAIN)
		ehc->tries[dev->devno]--;

	switch (err) {
	case -ENODEV:
		/* device missing or wrong IDENTIFY data, schedule probing */
		ehc->i.probe_mask |= (1 << dev->devno);
	case -EINVAL:
		/* give it just one more chance */
		ehc->tries[dev->devno] = min(ehc->tries[dev->devno], 1);
	case -EIO:
		if (ehc->tries[dev->devno] == 1) {
			/* This is the last chance, better to slow
			 * down than lose it.
			 */
			sata_down_spd_limit(ata_dev_phys_link(dev), 0);
			if (dev->pio_mode > XFER_PIO_0)
				ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
		}
	}

	if (ata_dev_enabled(dev) && !ehc->tries[dev->devno]) {
		/* disable device if it has used up all its chances */
		ata_dev_disable(dev);

		/* detach if offline */
		if (ata_phys_link_offline(ata_dev_phys_link(dev)))
			ata_eh_detach_dev(dev);

		/* schedule probe if necessary */
		if (ata_eh_schedule_probe(dev)) {
			ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
			memset(ehc->cmd_timeout_idx[dev->devno], 0,
			       sizeof(ehc->cmd_timeout_idx[dev->devno]));
		}

		return 1;
	} else {
		ehc->i.action |= ATA_EH_RESET;
		return 0;
	}
}

/**
 *	ata_eh_recover - recover host port after error
 *	@ap: host port to recover
 *	@prereset: prereset method (can be NULL)
 *	@softreset: softreset method (can be NULL)
 *	@hardreset: hardreset method (can be NULL)
 *	@postreset: postreset method (can be NULL)
 *	@r_failed_link: out parameter for failed link
 *
 *	This is the alpha and omega, eum and yang, heart and soul of
 *	libata exception handling.  On entry, actions required to
 *	recover each link and hotplug requests are recorded in the
 *	link's eh_context.  This function executes all the operations
 *	with appropriate retrials and fallbacks to resurrect failed
 *	devices, detach goners and greet newcomers.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
		   ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
		   ata_postreset_fn_t postreset,
		   struct ata_link **r_failed_link)
{
	struct ata_link *link;
	struct ata_device *dev;
	int rc, nr_fails;
	unsigned long flags, deadline;

	DPRINTK("ENTER\n");

	/* prep for recovery */
	ata_for_each_link(link, ap, EDGE) {
		struct ata_eh_context *ehc = &link->eh_context;

		/* re-enable link? */
		if (ehc->i.action & ATA_EH_ENABLE_LINK) {
			ata_eh_about_to_do(link, NULL, ATA_EH_ENABLE_LINK);
			spin_lock_irqsave(ap->lock, flags);
			link->flags &= ~ATA_LFLAG_DISABLED;
			spin_unlock_irqrestore(ap->lock, flags);
			ata_eh_done(link, NULL, ATA_EH_ENABLE_LINK);
		}

		ata_for_each_dev(dev, link, ALL) {
			if (link->flags & ATA_LFLAG_NO_RETRY)
				ehc->tries[dev->devno] = 1;
			else
				ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;

			/* collect port action mask recorded in dev actions */
			ehc->i.action |= ehc->i.dev_action[dev->devno] &
					 ~ATA_EH_PERDEV_MASK;
			ehc->i.dev_action[dev->devno] &= ATA_EH_PERDEV_MASK;

			/* process hotplug request */
			if (dev->flags & ATA_DFLAG_DETACH)
				ata_eh_detach_dev(dev);

			/* schedule probe if necessary */
			if (!ata_dev_enabled(dev))
				ata_eh_schedule_probe(dev);
		}
	}

 retry:
	rc = 0;

	/* if UNLOADING, finish immediately */
	if (ap->pflags & ATA_PFLAG_UNLOADING)
		goto out;

	/* prep for EH */
	ata_for_each_link(link, ap, EDGE) {
		struct ata_eh_context *ehc = &link->eh_context;

		/* skip EH if possible. */
		if (ata_eh_skip_recovery(link))
			ehc->i.action = 0;

		ata_for_each_dev(dev, link, ALL)
			ehc->classes[dev->devno] = ATA_DEV_UNKNOWN;
	}

	/* reset */
	ata_for_each_link(link, ap, EDGE) {
		struct ata_eh_context *ehc = &link->eh_context;

		if (!(ehc->i.action & ATA_EH_RESET))
			continue;

		rc = ata_eh_reset(link, ata_link_nr_vacant(link),
				  prereset, softreset, hardreset, postreset);
		if (rc) {
			ata_link_err(link, "reset failed, giving up\n");
			goto out;
		}
	}

	do {
		unsigned long now;

		/*
		 * clears ATA_EH_PARK in eh_info and resets
		 * ap->park_req_pending
		 */
		ata_eh_pull_park_action(ap);

		deadline = jiffies;
		ata_for_each_link(link, ap, EDGE) {
			ata_for_each_dev(dev, link, ALL) {
				struct ata_eh_context *ehc = &link->eh_context;
				unsigned long tmp;

				if (dev->class != ATA_DEV_ATA)
					continue;
				if (!(ehc->i.dev_action[dev->devno] &
				      ATA_EH_PARK))
					continue;
				tmp = dev->unpark_deadline;
				if (time_before(deadline, tmp))
					deadline = tmp;
				else if (time_before_eq(tmp, jiffies))
					continue;
				if (ehc->unloaded_mask & (1 << dev->devno))
					continue;

				ata_eh_park_issue_cmd(dev, 1);
			}
		}

		now = jiffies;
		if (time_before_eq(deadline, now))
			break;

		ata_eh_release(ap);
		deadline = wait_for_completion_timeout(&ap->park_req_pending,
						       deadline - now);
		ata_eh_acquire(ap);
	} while (deadline);
	ata_for_each_link(link, ap, EDGE) {
		ata_for_each_dev(dev, link, ALL) {
			if (!(link->eh_context.unloaded_mask &
			      (1 << dev->devno)))
				continue;

			ata_eh_park_issue_cmd(dev, 0);
			ata_eh_done(link, dev, ATA_EH_PARK);
		}
	}

	/* the rest */
	nr_fails = 0;
	ata_for_each_link(link, ap, PMP_FIRST) {
		struct ata_eh_context *ehc = &link->eh_context;

		if (sata_pmp_attached(ap) && ata_is_host_link(link))
			goto config_lpm;

		/* revalidate existing devices and attach new ones */
		rc = ata_eh_revalidate_and_attach(link, &dev);
		if (rc)
			goto rest_fail;

		/* if PMP got attached, return, pmp EH will take care of it */
		if (link->device->class == ATA_DEV_PMP) {
			ehc->i.action = 0;
			return 0;
		}

		/* configure transfer mode if necessary */
		if (ehc->i.flags & ATA_EHI_SETMODE) {
			rc = ata_set_mode(link, &dev);
			if (rc)
				goto rest_fail;
			ehc->i.flags &= ~ATA_EHI_SETMODE;
		}

		/* If reset has been issued, clear UA to avoid
		 * disrupting the current users of the device.
		 */
		if (ehc->i.flags & ATA_EHI_DID_RESET) {
			ata_for_each_dev(dev, link, ALL) {
				if (dev->class != ATA_DEV_ATAPI)
					continue;
				rc = atapi_eh_clear_ua(dev);
				if (rc)
					goto rest_fail;
			}
		}

		/* retry flush if necessary */
		ata_for_each_dev(dev, link, ALL) {
			if (dev->class != ATA_DEV_ATA)
				continue;
			rc = ata_eh_maybe_retry_flush(dev);
			if (rc)
				goto rest_fail;
		}

	config_lpm:
		/* configure link power saving */
		if (link->lpm_policy != ap->target_lpm_policy) {
			rc = ata_eh_set_lpm(link, ap->target_lpm_policy, &dev);
			if (rc)
				goto rest_fail;
		}

		/* this link is okay now */
		ehc->i.flags = 0;
		continue;

	rest_fail:
		nr_fails++;
		if (dev)
			ata_eh_handle_dev_fail(dev, rc);

		if (ap->pflags & ATA_PFLAG_FROZEN) {
			/* PMP reset requires working host port.
			 * Can't retry if it's frozen.
			 */
			if (sata_pmp_attached(ap))
				goto out;
			break;
		}
	}

	if (nr_fails)
		goto retry;

 out:
	if (rc && r_failed_link)
		*r_failed_link = link;

	DPRINTK("EXIT, rc=%d\n", rc);
	return rc;
}

/**
 *	ata_eh_finish - finish up EH
 *	@ap: host port to finish EH for
 *
 *	Recovery is complete.  Clean up EH states and retry or finish
 *	failed qcs.
 *
 *	LOCKING:
 *	None.
 */
void ata_eh_finish(struct ata_port *ap)
{
	int tag;

	/* retry or finish qcs */
	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);

		if (!(qc->flags & ATA_QCFLAG_FAILED))
			continue;

		if (qc->err_mask) {
			/* FIXME: Once EH migration is complete,
			 * generate sense data in this function,
			 * considering both err_mask and tf.
			 */
			if (qc->flags & ATA_QCFLAG_RETRY)
				ata_eh_qc_retry(qc);
			else
				ata_eh_qc_complete(qc);
		} else {
			if (qc->flags & ATA_QCFLAG_SENSE_VALID) {
				ata_eh_qc_complete(qc);
			} else {
				/* feed zero TF to sense generation */
				memset(&qc->result_tf, 0, sizeof(qc->result_tf));
				ata_eh_qc_retry(qc);
			}
		}
	}

	/* make sure nr_active_links is zero after EH */
	WARN_ON(ap->nr_active_links);
	ap->nr_active_links = 0;
}

/**
 *	ata_do_eh - do standard error handling
 *	@ap: host port to handle error for
 *
 *	@prereset: prereset method (can be NULL)
 *	@softreset: softreset method (can be NULL)
 *	@hardreset: hardreset method (can be NULL)
 *	@postreset: postreset method (can be NULL)
 *
 *	Perform standard error handling sequence.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
	       ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
	       ata_postreset_fn_t postreset)
{
	struct ata_device *dev;
	int rc;

	ata_eh_autopsy(ap);
	ata_eh_report(ap);

	rc = ata_eh_recover(ap, prereset, softreset, hardreset, postreset,
			    NULL);
	if (rc) {
		ata_for_each_dev(dev, &ap->link, ALL)
			ata_dev_disable(dev);
	}

	ata_eh_finish(ap);
}

/**
 *	ata_std_error_handler - standard error handler
 *	@ap: host port to handle error for
 *
 *	Standard error handler
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
void ata_std_error_handler(struct ata_port *ap)
{
	struct ata_port_operations *ops = ap->ops;
	ata_reset_fn_t hardreset = ops->hardreset;

	/* ignore built-in hardreset if SCR access is not available */
	if (hardreset == sata_std_hardreset && !sata_scr_valid(&ap->link))
		hardreset = NULL;

	ata_do_eh(ap, ops->prereset, ops->softreset, hardreset, ops->postreset);
}

#ifdef CONFIG_PM
/**
 *	ata_eh_handle_port_suspend - perform port suspend operation
 *	@ap: port to suspend
 *
 *	Suspend @ap.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
static void ata_eh_handle_port_suspend(struct ata_port *ap)
{
	unsigned long flags;
	int rc = 0;

	/* are we suspending? */
	spin_lock_irqsave(ap->lock, flags);
	if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
	    ap->pm_mesg.event == PM_EVENT_ON) {
		spin_unlock_irqrestore(ap->lock, flags);
		return;
	}
	spin_unlock_irqrestore(ap->lock, flags);

	WARN_ON(ap->pflags & ATA_PFLAG_SUSPENDED);

	/* tell ACPI we're suspending */
	rc = ata_acpi_on_suspend(ap);
	if (rc)
		goto out;

	/* suspend */
	ata_eh_freeze_port(ap);

	if (ap->ops->port_suspend)
		rc = ap->ops->port_suspend(ap, ap->pm_mesg);

	ata_acpi_set_state(ap, PMSG_SUSPEND);
 out:
	/* report result */
	spin_lock_irqsave(ap->lock, flags);

	ap->pflags &= ~ATA_PFLAG_PM_PENDING;
	if (rc == 0)
		ap->pflags |= ATA_PFLAG_SUSPENDED;
	else if (ap->pflags & ATA_PFLAG_FROZEN)
		ata_port_schedule_eh(ap);

	if (ap->pm_result) {
		*ap->pm_result = rc;
		ap->pm_result = NULL;
	}

	spin_unlock_irqrestore(ap->lock, flags);

	return;
}

/**
 *	ata_eh_handle_port_resume - perform port resume operation
 *	@ap: port to resume
 *
 *	Resume @ap.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
static void ata_eh_handle_port_resume(struct ata_port *ap)
{
	struct ata_link *link;
	struct ata_device *dev;
	unsigned long flags;
	int rc = 0;

	/* are we resuming? */
	spin_lock_irqsave(ap->lock, flags);
	if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
	    ap->pm_mesg.event != PM_EVENT_ON) {
		spin_unlock_irqrestore(ap->lock, flags);
		return;
	}
	spin_unlock_irqrestore(ap->lock, flags);

	WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));

	/*
	 * Error timestamps are in jiffies which doesn't run while
	 * suspended and PHY events during resume isn't too uncommon.
	 * When the two are combined, it can lead to unnecessary speed
	 * downs if the machine is suspended and resumed repeatedly.
	 * Clear error history.
	 */
	ata_for_each_link(link, ap, HOST_FIRST)
		ata_for_each_dev(dev, link, ALL)
			ata_ering_clear(&dev->ering);

	ata_acpi_set_state(ap, PMSG_ON);

	if (ap->ops->port_resume)
		rc = ap->ops->port_resume(ap);

	/* tell ACPI that we're resuming */
	ata_acpi_on_resume(ap);

	/* report result */
	spin_lock_irqsave(ap->lock, flags);
	ap->pflags &= ~(ATA_PFLAG_PM_PENDING | ATA_PFLAG_SUSPENDED);
	if (ap->pm_result) {
		*ap->pm_result = rc;
		ap->pm_result = NULL;
	}
	spin_unlock_irqrestore(ap->lock, flags);
}
#endif /* CONFIG_PM */