aboutsummaryrefslogtreecommitdiff
path: root/hw/net/cadence_gem.c
blob: 8a4be1e66719c5b22d0c868c4eed87b13be7f1a8 (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
/*
 * QEMU Cadence GEM emulation
 *
 * Copyright (c) 2011 Xilinx, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "qemu/osdep.h"
#include <zlib.h> /* For crc32 */

#include "hw/net/cadence_gem.h"
#include "net/checksum.h"

#ifdef CADENCE_GEM_ERR_DEBUG
#define DB_PRINT(...) do { \
    fprintf(stderr,  ": %s: ", __func__); \
    fprintf(stderr, ## __VA_ARGS__); \
    } while (0);
#else
    #define DB_PRINT(...)
#endif

#define GEM_NWCTRL        (0x00000000/4) /* Network Control reg */
#define GEM_NWCFG         (0x00000004/4) /* Network Config reg */
#define GEM_NWSTATUS      (0x00000008/4) /* Network Status reg */
#define GEM_USERIO        (0x0000000C/4) /* User IO reg */
#define GEM_DMACFG        (0x00000010/4) /* DMA Control reg */
#define GEM_TXSTATUS      (0x00000014/4) /* TX Status reg */
#define GEM_RXQBASE       (0x00000018/4) /* RX Q Base address reg */
#define GEM_TXQBASE       (0x0000001C/4) /* TX Q Base address reg */
#define GEM_RXSTATUS      (0x00000020/4) /* RX Status reg */
#define GEM_ISR           (0x00000024/4) /* Interrupt Status reg */
#define GEM_IER           (0x00000028/4) /* Interrupt Enable reg */
#define GEM_IDR           (0x0000002C/4) /* Interrupt Disable reg */
#define GEM_IMR           (0x00000030/4) /* Interrupt Mask reg */
#define GEM_PHYMNTNC      (0x00000034/4) /* Phy Maintenance reg */
#define GEM_RXPAUSE       (0x00000038/4) /* RX Pause Time reg */
#define GEM_TXPAUSE       (0x0000003C/4) /* TX Pause Time reg */
#define GEM_TXPARTIALSF   (0x00000040/4) /* TX Partial Store and Forward */
#define GEM_RXPARTIALSF   (0x00000044/4) /* RX Partial Store and Forward */
#define GEM_HASHLO        (0x00000080/4) /* Hash Low address reg */
#define GEM_HASHHI        (0x00000084/4) /* Hash High address reg */
#define GEM_SPADDR1LO     (0x00000088/4) /* Specific addr 1 low reg */
#define GEM_SPADDR1HI     (0x0000008C/4) /* Specific addr 1 high reg */
#define GEM_SPADDR2LO     (0x00000090/4) /* Specific addr 2 low reg */
#define GEM_SPADDR2HI     (0x00000094/4) /* Specific addr 2 high reg */
#define GEM_SPADDR3LO     (0x00000098/4) /* Specific addr 3 low reg */
#define GEM_SPADDR3HI     (0x0000009C/4) /* Specific addr 3 high reg */
#define GEM_SPADDR4LO     (0x000000A0/4) /* Specific addr 4 low reg */
#define GEM_SPADDR4HI     (0x000000A4/4) /* Specific addr 4 high reg */
#define GEM_TIDMATCH1     (0x000000A8/4) /* Type ID1 Match reg */
#define GEM_TIDMATCH2     (0x000000AC/4) /* Type ID2 Match reg */
#define GEM_TIDMATCH3     (0x000000B0/4) /* Type ID3 Match reg */
#define GEM_TIDMATCH4     (0x000000B4/4) /* Type ID4 Match reg */
#define GEM_WOLAN         (0x000000B8/4) /* Wake on LAN reg */
#define GEM_IPGSTRETCH    (0x000000BC/4) /* IPG Stretch reg */
#define GEM_SVLAN         (0x000000C0/4) /* Stacked VLAN reg */
#define GEM_MODID         (0x000000FC/4) /* Module ID reg */
#define GEM_OCTTXLO       (0x00000100/4) /* Octects transmitted Low reg */
#define GEM_OCTTXHI       (0x00000104/4) /* Octects transmitted High reg */
#define GEM_TXCNT         (0x00000108/4) /* Error-free Frames transmitted */
#define GEM_TXBCNT        (0x0000010C/4) /* Error-free Broadcast Frames */
#define GEM_TXMCNT        (0x00000110/4) /* Error-free Multicast Frame */
#define GEM_TXPAUSECNT    (0x00000114/4) /* Pause Frames Transmitted */
#define GEM_TX64CNT       (0x00000118/4) /* Error-free 64 TX */
#define GEM_TX65CNT       (0x0000011C/4) /* Error-free 65-127 TX */
#define GEM_TX128CNT      (0x00000120/4) /* Error-free 128-255 TX */
#define GEM_TX256CNT      (0x00000124/4) /* Error-free 256-511 */
#define GEM_TX512CNT      (0x00000128/4) /* Error-free 512-1023 TX */
#define GEM_TX1024CNT     (0x0000012C/4) /* Error-free 1024-1518 TX */
#define GEM_TX1519CNT     (0x00000130/4) /* Error-free larger than 1519 TX */
#define GEM_TXURUNCNT     (0x00000134/4) /* TX under run error counter */
#define GEM_SINGLECOLLCNT (0x00000138/4) /* Single Collision Frames */
#define GEM_MULTCOLLCNT   (0x0000013C/4) /* Multiple Collision Frames */
#define GEM_EXCESSCOLLCNT (0x00000140/4) /* Excessive Collision Frames */
#define GEM_LATECOLLCNT   (0x00000144/4) /* Late Collision Frames */
#define GEM_DEFERTXCNT    (0x00000148/4) /* Deferred Transmission Frames */
#define GEM_CSENSECNT     (0x0000014C/4) /* Carrier Sense Error Counter */
#define GEM_OCTRXLO       (0x00000150/4) /* Octects Received register Low */
#define GEM_OCTRXHI       (0x00000154/4) /* Octects Received register High */
#define GEM_RXCNT         (0x00000158/4) /* Error-free Frames Received */
#define GEM_RXBROADCNT    (0x0000015C/4) /* Error-free Broadcast Frames RX */
#define GEM_RXMULTICNT    (0x00000160/4) /* Error-free Multicast Frames RX */
#define GEM_RXPAUSECNT    (0x00000164/4) /* Pause Frames Received Counter */
#define GEM_RX64CNT       (0x00000168/4) /* Error-free 64 byte Frames RX */
#define GEM_RX65CNT       (0x0000016C/4) /* Error-free 65-127B Frames RX */
#define GEM_RX128CNT      (0x00000170/4) /* Error-free 128-255B Frames RX */
#define GEM_RX256CNT      (0x00000174/4) /* Error-free 256-512B Frames RX */
#define GEM_RX512CNT      (0x00000178/4) /* Error-free 512-1023B Frames RX */
#define GEM_RX1024CNT     (0x0000017C/4) /* Error-free 1024-1518B Frames RX */
#define GEM_RX1519CNT     (0x00000180/4) /* Error-free 1519-max Frames RX */
#define GEM_RXUNDERCNT    (0x00000184/4) /* Undersize Frames Received */
#define GEM_RXOVERCNT     (0x00000188/4) /* Oversize Frames Received */
#define GEM_RXJABCNT      (0x0000018C/4) /* Jabbers Received Counter */
#define GEM_RXFCSCNT      (0x00000190/4) /* Frame Check seq. Error Counter */
#define GEM_RXLENERRCNT   (0x00000194/4) /* Length Field Error Counter */
#define GEM_RXSYMERRCNT   (0x00000198/4) /* Symbol Error Counter */
#define GEM_RXALIGNERRCNT (0x0000019C/4) /* Alignment Error Counter */
#define GEM_RXRSCERRCNT   (0x000001A0/4) /* Receive Resource Error Counter */
#define GEM_RXORUNCNT     (0x000001A4/4) /* Receive Overrun Counter */
#define GEM_RXIPCSERRCNT  (0x000001A8/4) /* IP header Checksum Error Counter */
#define GEM_RXTCPCCNT     (0x000001AC/4) /* TCP Checksum Error Counter */
#define GEM_RXUDPCCNT     (0x000001B0/4) /* UDP Checksum Error Counter */

#define GEM_1588S         (0x000001D0/4) /* 1588 Timer Seconds */
#define GEM_1588NS        (0x000001D4/4) /* 1588 Timer Nanoseconds */
#define GEM_1588ADJ       (0x000001D8/4) /* 1588 Timer Adjust */
#define GEM_1588INC       (0x000001DC/4) /* 1588 Timer Increment */
#define GEM_PTPETXS       (0x000001E0/4) /* PTP Event Frame Transmitted (s) */
#define GEM_PTPETXNS      (0x000001E4/4) /* PTP Event Frame Transmitted (ns) */
#define GEM_PTPERXS       (0x000001E8/4) /* PTP Event Frame Received (s) */
#define GEM_PTPERXNS      (0x000001EC/4) /* PTP Event Frame Received (ns) */
#define GEM_PTPPTXS       (0x000001E0/4) /* PTP Peer Frame Transmitted (s) */
#define GEM_PTPPTXNS      (0x000001E4/4) /* PTP Peer Frame Transmitted (ns) */
#define GEM_PTPPRXS       (0x000001E8/4) /* PTP Peer Frame Received (s) */
#define GEM_PTPPRXNS      (0x000001EC/4) /* PTP Peer Frame Received (ns) */

/* Design Configuration Registers */
#define GEM_DESCONF       (0x00000280/4)
#define GEM_DESCONF2      (0x00000284/4)
#define GEM_DESCONF3      (0x00000288/4)
#define GEM_DESCONF4      (0x0000028C/4)
#define GEM_DESCONF5      (0x00000290/4)
#define GEM_DESCONF6      (0x00000294/4)
#define GEM_DESCONF7      (0x00000298/4)

/*****************************************/
#define GEM_NWCTRL_TXSTART     0x00000200 /* Transmit Enable */
#define GEM_NWCTRL_TXENA       0x00000008 /* Transmit Enable */
#define GEM_NWCTRL_RXENA       0x00000004 /* Receive Enable */
#define GEM_NWCTRL_LOCALLOOP   0x00000002 /* Local Loopback */

#define GEM_NWCFG_STRIP_FCS    0x00020000 /* Strip FCS field */
#define GEM_NWCFG_LERR_DISC    0x00010000 /* Discard RX frames with len err */
#define GEM_NWCFG_BUFF_OFST_M  0x0000C000 /* Receive buffer offset mask */
#define GEM_NWCFG_BUFF_OFST_S  14         /* Receive buffer offset shift */
#define GEM_NWCFG_UCAST_HASH   0x00000080 /* accept unicast if hash match */
#define GEM_NWCFG_MCAST_HASH   0x00000040 /* accept multicast if hash match */
#define GEM_NWCFG_BCAST_REJ    0x00000020 /* Reject broadcast packets */
#define GEM_NWCFG_PROMISC      0x00000010 /* Accept all packets */

#define GEM_DMACFG_RBUFSZ_M    0x00FF0000 /* DMA RX Buffer Size mask */
#define GEM_DMACFG_RBUFSZ_S    16         /* DMA RX Buffer Size shift */
#define GEM_DMACFG_RBUFSZ_MUL  64         /* DMA RX Buffer Size multiplier */
#define GEM_DMACFG_TXCSUM_OFFL 0x00000800 /* Transmit checksum offload */

#define GEM_TXSTATUS_TXCMPL    0x00000020 /* Transmit Complete */
#define GEM_TXSTATUS_USED      0x00000001 /* sw owned descriptor encountered */

#define GEM_RXSTATUS_FRMRCVD   0x00000002 /* Frame received */
#define GEM_RXSTATUS_NOBUF     0x00000001 /* Buffer unavailable */

/* GEM_ISR GEM_IER GEM_IDR GEM_IMR */
#define GEM_INT_TXCMPL        0x00000080 /* Transmit Complete */
#define GEM_INT_TXUSED         0x00000008
#define GEM_INT_RXUSED         0x00000004
#define GEM_INT_RXCMPL        0x00000002

#define GEM_PHYMNTNC_OP_R      0x20000000 /* read operation */
#define GEM_PHYMNTNC_OP_W      0x10000000 /* write operation */
#define GEM_PHYMNTNC_ADDR      0x0F800000 /* Address bits */
#define GEM_PHYMNTNC_ADDR_SHFT 23
#define GEM_PHYMNTNC_REG       0x007C0000 /* register bits */
#define GEM_PHYMNTNC_REG_SHIFT 18

/* Marvell PHY definitions */
#define BOARD_PHY_ADDRESS    23 /* PHY address we will emulate a device at */

#define PHY_REG_CONTROL      0
#define PHY_REG_STATUS       1
#define PHY_REG_PHYID1       2
#define PHY_REG_PHYID2       3
#define PHY_REG_ANEGADV      4
#define PHY_REG_LINKPABIL    5
#define PHY_REG_ANEGEXP      6
#define PHY_REG_NEXTP        7
#define PHY_REG_LINKPNEXTP   8
#define PHY_REG_100BTCTRL    9
#define PHY_REG_1000BTSTAT   10
#define PHY_REG_EXTSTAT      15
#define PHY_REG_PHYSPCFC_CTL 16
#define PHY_REG_PHYSPCFC_ST  17
#define PHY_REG_INT_EN       18
#define PHY_REG_INT_ST       19
#define PHY_REG_EXT_PHYSPCFC_CTL  20
#define PHY_REG_RXERR        21
#define PHY_REG_EACD         22
#define PHY_REG_LED          24
#define PHY_REG_LED_OVRD     25
#define PHY_REG_EXT_PHYSPCFC_CTL2 26
#define PHY_REG_EXT_PHYSPCFC_ST   27
#define PHY_REG_CABLE_DIAG   28

#define PHY_REG_CONTROL_RST  0x8000
#define PHY_REG_CONTROL_LOOP 0x4000
#define PHY_REG_CONTROL_ANEG 0x1000

#define PHY_REG_STATUS_LINK     0x0004
#define PHY_REG_STATUS_ANEGCMPL 0x0020

#define PHY_REG_INT_ST_ANEGCMPL 0x0800
#define PHY_REG_INT_ST_LINKC    0x0400
#define PHY_REG_INT_ST_ENERGY   0x0010

/***********************************************************************/
#define GEM_RX_REJECT                   (-1)
#define GEM_RX_PROMISCUOUS_ACCEPT       (-2)
#define GEM_RX_BROADCAST_ACCEPT         (-3)
#define GEM_RX_MULTICAST_HASH_ACCEPT    (-4)
#define GEM_RX_UNICAST_HASH_ACCEPT      (-5)

#define GEM_RX_SAR_ACCEPT               0

/***********************************************************************/

#define DESC_1_USED 0x80000000
#define DESC_1_LENGTH 0x00001FFF

#define DESC_1_TX_WRAP 0x40000000
#define DESC_1_TX_LAST 0x00008000

#define DESC_0_RX_WRAP 0x00000002
#define DESC_0_RX_OWNERSHIP 0x00000001

#define R_DESC_1_RX_SAR_SHIFT           25
#define R_DESC_1_RX_SAR_LENGTH          2
#define R_DESC_1_RX_SAR_MATCH           (1 << 27)
#define R_DESC_1_RX_UNICAST_HASH        (1 << 29)
#define R_DESC_1_RX_MULTICAST_HASH      (1 << 30)
#define R_DESC_1_RX_BROADCAST           (1 << 31)

#define DESC_1_RX_SOF 0x00004000
#define DESC_1_RX_EOF 0x00008000

static inline unsigned tx_desc_get_buffer(unsigned *desc)
{
    return desc[0];
}

static inline unsigned tx_desc_get_used(unsigned *desc)
{
    return (desc[1] & DESC_1_USED) ? 1 : 0;
}

static inline void tx_desc_set_used(unsigned *desc)
{
    desc[1] |= DESC_1_USED;
}

static inline unsigned tx_desc_get_wrap(unsigned *desc)
{
    return (desc[1] & DESC_1_TX_WRAP) ? 1 : 0;
}

static inline unsigned tx_desc_get_last(unsigned *desc)
{
    return (desc[1] & DESC_1_TX_LAST) ? 1 : 0;
}

static inline void tx_desc_set_last(unsigned *desc)
{
    desc[1] |= DESC_1_TX_LAST;
}

static inline unsigned tx_desc_get_length(unsigned *desc)
{
    return desc[1] & DESC_1_LENGTH;
}

static inline void print_gem_tx_desc(unsigned *desc)
{
    DB_PRINT("TXDESC:\n");
    DB_PRINT("bufaddr: 0x%08x\n", *desc);
    DB_PRINT("used_hw: %d\n", tx_desc_get_used(desc));
    DB_PRINT("wrap:    %d\n", tx_desc_get_wrap(desc));
    DB_PRINT("last:    %d\n", tx_desc_get_last(desc));
    DB_PRINT("length:  %d\n", tx_desc_get_length(desc));
}

static inline unsigned rx_desc_get_buffer(unsigned *desc)
{
    return desc[0] & ~0x3UL;
}

static inline unsigned rx_desc_get_wrap(unsigned *desc)
{
    return desc[0] & DESC_0_RX_WRAP ? 1 : 0;
}

static inline unsigned rx_desc_get_ownership(unsigned *desc)
{
    return desc[0] & DESC_0_RX_OWNERSHIP ? 1 : 0;
}

static inline void rx_desc_set_ownership(unsigned *desc)
{
    desc[0] |= DESC_0_RX_OWNERSHIP;
}

static inline void rx_desc_set_sof(unsigned *desc)
{
    desc[1] |= DESC_1_RX_SOF;
}

static inline void rx_desc_set_eof(unsigned *desc)
{
    desc[1] |= DESC_1_RX_EOF;
}

static inline void rx_desc_set_length(unsigned *desc, unsigned len)
{
    desc[1] &= ~DESC_1_LENGTH;
    desc[1] |= len;
}

static inline void rx_desc_set_broadcast(unsigned *desc)
{
    desc[1] |= R_DESC_1_RX_BROADCAST;
}

static inline void rx_desc_set_unicast_hash(unsigned *desc)
{
    desc[1] |= R_DESC_1_RX_UNICAST_HASH;
}

static inline void rx_desc_set_multicast_hash(unsigned *desc)
{
    desc[1] |= R_DESC_1_RX_MULTICAST_HASH;
}

static inline void rx_desc_set_sar(unsigned *desc, int sar_idx)
{
    desc[1] = deposit32(desc[1], R_DESC_1_RX_SAR_SHIFT, R_DESC_1_RX_SAR_LENGTH,
                        sar_idx);
    desc[1] |= R_DESC_1_RX_SAR_MATCH;
}

/* The broadcast MAC address: 0xFFFFFFFFFFFF */
static const uint8_t broadcast_addr[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };

/*
 * gem_init_register_masks:
 * One time initialization.
 * Set masks to identify which register bits have magical clear properties
 */
static void gem_init_register_masks(CadenceGEMState *s)
{
    /* Mask of register bits which are read only */
    memset(&s->regs_ro[0], 0, sizeof(s->regs_ro));
    s->regs_ro[GEM_NWCTRL]   = 0xFFF80000;
    s->regs_ro[GEM_NWSTATUS] = 0xFFFFFFFF;
    s->regs_ro[GEM_DMACFG]   = 0xFE00F000;
    s->regs_ro[GEM_TXSTATUS] = 0xFFFFFE08;
    s->regs_ro[GEM_RXQBASE]  = 0x00000003;
    s->regs_ro[GEM_TXQBASE]  = 0x00000003;
    s->regs_ro[GEM_RXSTATUS] = 0xFFFFFFF0;
    s->regs_ro[GEM_ISR]      = 0xFFFFFFFF;
    s->regs_ro[GEM_IMR]      = 0xFFFFFFFF;
    s->regs_ro[GEM_MODID]    = 0xFFFFFFFF;

    /* Mask of register bits which are clear on read */
    memset(&s->regs_rtc[0], 0, sizeof(s->regs_rtc));
    s->regs_rtc[GEM_ISR]      = 0xFFFFFFFF;

    /* Mask of register bits which are write 1 to clear */
    memset(&s->regs_w1c[0], 0, sizeof(s->regs_w1c));
    s->regs_w1c[GEM_TXSTATUS] = 0x000001F7;
    s->regs_w1c[GEM_RXSTATUS] = 0x0000000F;

    /* Mask of register bits which are write only */
    memset(&s->regs_wo[0], 0, sizeof(s->regs_wo));
    s->regs_wo[GEM_NWCTRL]   = 0x00073E60;
    s->regs_wo[GEM_IER]      = 0x07FFFFFF;
    s->regs_wo[GEM_IDR]      = 0x07FFFFFF;
}

/*
 * phy_update_link:
 * Make the emulated PHY link state match the QEMU "interface" state.
 */
static void phy_update_link(CadenceGEMState *s)
{
    DB_PRINT("down %d\n", qemu_get_queue(s->nic)->link_down);

    /* Autonegotiation status mirrors link status.  */
    if (qemu_get_queue(s->nic)->link_down) {
        s->phy_regs[PHY_REG_STATUS] &= ~(PHY_REG_STATUS_ANEGCMPL |
                                         PHY_REG_STATUS_LINK);
        s->phy_regs[PHY_REG_INT_ST] |= PHY_REG_INT_ST_LINKC;
    } else {
        s->phy_regs[PHY_REG_STATUS] |= (PHY_REG_STATUS_ANEGCMPL |
                                         PHY_REG_STATUS_LINK);
        s->phy_regs[PHY_REG_INT_ST] |= (PHY_REG_INT_ST_LINKC |
                                        PHY_REG_INT_ST_ANEGCMPL |
                                        PHY_REG_INT_ST_ENERGY);
    }
}

static int gem_can_receive(NetClientState *nc)
{
    CadenceGEMState *s;

    s = qemu_get_nic_opaque(nc);

    /* Do nothing if receive is not enabled. */
    if (!(s->regs[GEM_NWCTRL] & GEM_NWCTRL_RXENA)) {
        if (s->can_rx_state != 1) {
            s->can_rx_state = 1;
            DB_PRINT("can't receive - no enable\n");
        }
        return 0;
    }

    if (rx_desc_get_ownership(s->rx_desc) == 1) {
        if (s->can_rx_state != 2) {
            s->can_rx_state = 2;
            DB_PRINT("can't receive - busy buffer descriptor 0x%x\n",
                     s->rx_desc_addr);
        }
        return 0;
    }

    if (s->can_rx_state != 0) {
        s->can_rx_state = 0;
        DB_PRINT("can receive 0x%x\n", s->rx_desc_addr);
    }
    return 1;
}

/*
 * gem_update_int_status:
 * Raise or lower interrupt based on current status.
 */
static void gem_update_int_status(CadenceGEMState *s)
{
    if (s->regs[GEM_ISR]) {
        DB_PRINT("asserting int. (0x%08x)\n", s->regs[GEM_ISR]);
        qemu_set_irq(s->irq, 1);
    }
}

/*
 * gem_receive_updatestats:
 * Increment receive statistics.
 */
static void gem_receive_updatestats(CadenceGEMState *s, const uint8_t *packet,
                                    unsigned bytes)
{
    uint64_t octets;

    /* Total octets (bytes) received */
    octets = ((uint64_t)(s->regs[GEM_OCTRXLO]) << 32) |
             s->regs[GEM_OCTRXHI];
    octets += bytes;
    s->regs[GEM_OCTRXLO] = octets >> 32;
    s->regs[GEM_OCTRXHI] = octets;

    /* Error-free Frames received */
    s->regs[GEM_RXCNT]++;

    /* Error-free Broadcast Frames counter */
    if (!memcmp(packet, broadcast_addr, 6)) {
        s->regs[GEM_RXBROADCNT]++;
    }

    /* Error-free Multicast Frames counter */
    if (packet[0] == 0x01) {
        s->regs[GEM_RXMULTICNT]++;
    }

    if (bytes <= 64) {
        s->regs[GEM_RX64CNT]++;
    } else if (bytes <= 127) {
        s->regs[GEM_RX65CNT]++;
    } else if (bytes <= 255) {
        s->regs[GEM_RX128CNT]++;
    } else if (bytes <= 511) {
        s->regs[GEM_RX256CNT]++;
    } else if (bytes <= 1023) {
        s->regs[GEM_RX512CNT]++;
    } else if (bytes <= 1518) {
        s->regs[GEM_RX1024CNT]++;
    } else {
        s->regs[GEM_RX1519CNT]++;
    }
}

/*
 * Get the MAC Address bit from the specified position
 */
static unsigned get_bit(const uint8_t *mac, unsigned bit)
{
    unsigned byte;

    byte = mac[bit / 8];
    byte >>= (bit & 0x7);
    byte &= 1;

    return byte;
}

/*
 * Calculate a GEM MAC Address hash index
 */
static unsigned calc_mac_hash(const uint8_t *mac)
{
    int index_bit, mac_bit;
    unsigned hash_index;

    hash_index = 0;
    mac_bit = 5;
    for (index_bit = 5; index_bit >= 0; index_bit--) {
        hash_index |= (get_bit(mac,  mac_bit) ^
                               get_bit(mac, mac_bit + 6) ^
                               get_bit(mac, mac_bit + 12) ^
                               get_bit(mac, mac_bit + 18) ^
                               get_bit(mac, mac_bit + 24) ^
                               get_bit(mac, mac_bit + 30) ^
                               get_bit(mac, mac_bit + 36) ^
                               get_bit(mac, mac_bit + 42)) << index_bit;
        mac_bit--;
    }

    return hash_index;
}

/*
 * gem_mac_address_filter:
 * Accept or reject this destination address?
 * Returns:
 * GEM_RX_REJECT: reject
 * >= 0: Specific address accept (which matched SAR is returned)
 * others for various other modes of accept:
 * GEM_RM_PROMISCUOUS_ACCEPT, GEM_RX_BROADCAST_ACCEPT,
 * GEM_RX_MULTICAST_HASH_ACCEPT or GEM_RX_UNICAST_HASH_ACCEPT
 */
static int gem_mac_address_filter(CadenceGEMState *s, const uint8_t *packet)
{
    uint8_t *gem_spaddr;
    int i;

    /* Promiscuous mode? */
    if (s->regs[GEM_NWCFG] & GEM_NWCFG_PROMISC) {
        return GEM_RX_PROMISCUOUS_ACCEPT;
    }

    if (!memcmp(packet, broadcast_addr, 6)) {
        /* Reject broadcast packets? */
        if (s->regs[GEM_NWCFG] & GEM_NWCFG_BCAST_REJ) {
            return GEM_RX_REJECT;
        }
        return GEM_RX_BROADCAST_ACCEPT;
    }

    /* Accept packets -w- hash match? */
    if ((packet[0] == 0x01 && (s->regs[GEM_NWCFG] & GEM_NWCFG_MCAST_HASH)) ||
        (packet[0] != 0x01 && (s->regs[GEM_NWCFG] & GEM_NWCFG_UCAST_HASH))) {
        unsigned hash_index;

        hash_index = calc_mac_hash(packet);
        if (hash_index < 32) {
            if (s->regs[GEM_HASHLO] & (1<<hash_index)) {
                return packet[0] == 0x01 ? GEM_RX_MULTICAST_HASH_ACCEPT :
                                           GEM_RX_UNICAST_HASH_ACCEPT;
            }
        } else {
            hash_index -= 32;
            if (s->regs[GEM_HASHHI] & (1<<hash_index)) {
                return packet[0] == 0x01 ? GEM_RX_MULTICAST_HASH_ACCEPT :
                                           GEM_RX_UNICAST_HASH_ACCEPT;
            }
        }
    }

    /* Check all 4 specific addresses */
    gem_spaddr = (uint8_t *)&(s->regs[GEM_SPADDR1LO]);
    for (i = 3; i >= 0; i--) {
        if (s->sar_active[i] && !memcmp(packet, gem_spaddr + 8 * i, 6)) {
            return GEM_RX_SAR_ACCEPT + i;
        }
    }

    /* No address match; reject the packet */
    return GEM_RX_REJECT;
}

static void gem_get_rx_desc(CadenceGEMState *s)
{
    DB_PRINT("read descriptor 0x%x\n", (unsigned)s->rx_desc_addr);
    /* read current descriptor */
    cpu_physical_memory_read(s->rx_desc_addr,
                             (uint8_t *)s->rx_desc, sizeof(s->rx_desc));

    /* Descriptor owned by software ? */
    if (rx_desc_get_ownership(s->rx_desc) == 1) {
        DB_PRINT("descriptor 0x%x owned by sw.\n",
                 (unsigned)s->rx_desc_addr);
        s->regs[GEM_RXSTATUS] |= GEM_RXSTATUS_NOBUF;
        s->regs[GEM_ISR] |= GEM_INT_RXUSED & ~(s->regs[GEM_IMR]);
        /* Handle interrupt consequences */
        gem_update_int_status(s);
    }
}

/*
 * gem_receive:
 * Fit a packet handed to us by QEMU into the receive descriptor ring.
 */
static ssize_t gem_receive(NetClientState *nc, const uint8_t *buf, size_t size)
{
    CadenceGEMState *s;
    unsigned   rxbufsize, bytes_to_copy;
    unsigned   rxbuf_offset;
    uint8_t    rxbuf[2048];
    uint8_t   *rxbuf_ptr;
    bool first_desc = true;
    int maf;

    s = qemu_get_nic_opaque(nc);

    /* Is this destination MAC address "for us" ? */
    maf = gem_mac_address_filter(s, buf);
    if (maf == GEM_RX_REJECT) {
        return -1;
    }

    /* Discard packets with receive length error enabled ? */
    if (s->regs[GEM_NWCFG] & GEM_NWCFG_LERR_DISC) {
        unsigned type_len;

        /* Fish the ethertype / length field out of the RX packet */
        type_len = buf[12] << 8 | buf[13];
        /* It is a length field, not an ethertype */
        if (type_len < 0x600) {
            if (size < type_len) {
                /* discard */
                return -1;
            }
        }
    }

    /*
     * Determine configured receive buffer offset (probably 0)
     */
    rxbuf_offset = (s->regs[GEM_NWCFG] & GEM_NWCFG_BUFF_OFST_M) >>
                   GEM_NWCFG_BUFF_OFST_S;

    /* The configure size of each receive buffer.  Determines how many
     * buffers needed to hold this packet.
     */
    rxbufsize = ((s->regs[GEM_DMACFG] & GEM_DMACFG_RBUFSZ_M) >>
                 GEM_DMACFG_RBUFSZ_S) * GEM_DMACFG_RBUFSZ_MUL;
    bytes_to_copy = size;

    /* Hardware allows a zero value here but warns against it. To avoid QEMU
     * indefinite loops we enforce a minimum value here
     */
    if (rxbufsize < GEM_DMACFG_RBUFSZ_MUL) {
        rxbufsize = GEM_DMACFG_RBUFSZ_MUL;
    }

    /* Pad to minimum length. Assume FCS field is stripped, logic
     * below will increment it to the real minimum of 64 when
     * not FCS stripping
     */
    if (size < 60) {
        size = 60;
    }

    /* Strip of FCS field ? (usually yes) */
    if (s->regs[GEM_NWCFG] & GEM_NWCFG_STRIP_FCS) {
        rxbuf_ptr = (void *)buf;
    } else {
        unsigned crc_val;

        if (size > sizeof(rxbuf) - sizeof(crc_val)) {
            size = sizeof(rxbuf) - sizeof(crc_val);
        }
        bytes_to_copy = size;
        /* The application wants the FCS field, which QEMU does not provide.
         * We must try and calculate one.
         */

        memcpy(rxbuf, buf, size);
        memset(rxbuf + size, 0, sizeof(rxbuf) - size);
        rxbuf_ptr = rxbuf;
        crc_val = cpu_to_le32(crc32(0, rxbuf, MAX(size, 60)));
        memcpy(rxbuf + size, &crc_val, sizeof(crc_val));

        bytes_to_copy += 4;
        size += 4;
    }

    DB_PRINT("config bufsize: %d packet size: %ld\n", rxbufsize, size);

    while (bytes_to_copy) {
        /* Do nothing if receive is not enabled. */
        if (!gem_can_receive(nc)) {
            assert(!first_desc);
            return -1;
        }

        DB_PRINT("copy %d bytes to 0x%x\n", MIN(bytes_to_copy, rxbufsize),
                rx_desc_get_buffer(s->rx_desc));

        /* Copy packet data to emulated DMA buffer */
        cpu_physical_memory_write(rx_desc_get_buffer(s->rx_desc) + rxbuf_offset,
                                  rxbuf_ptr, MIN(bytes_to_copy, rxbufsize));
        rxbuf_ptr += MIN(bytes_to_copy, rxbufsize);
        bytes_to_copy -= MIN(bytes_to_copy, rxbufsize);

        /* Update the descriptor.  */
        if (first_desc) {
            rx_desc_set_sof(s->rx_desc);
            first_desc = false;
        }
        if (bytes_to_copy == 0) {
            rx_desc_set_eof(s->rx_desc);
            rx_desc_set_length(s->rx_desc, size);
        }
        rx_desc_set_ownership(s->rx_desc);

        switch (maf) {
        case GEM_RX_PROMISCUOUS_ACCEPT:
            break;
        case GEM_RX_BROADCAST_ACCEPT:
            rx_desc_set_broadcast(s->rx_desc);
            break;
        case GEM_RX_UNICAST_HASH_ACCEPT:
            rx_desc_set_unicast_hash(s->rx_desc);
            break;
        case GEM_RX_MULTICAST_HASH_ACCEPT:
            rx_desc_set_multicast_hash(s->rx_desc);
            break;
        case GEM_RX_REJECT:
            abort();
        default: /* SAR */
            rx_desc_set_sar(s->rx_desc, maf);
        }

        /* Descriptor write-back.  */
        cpu_physical_memory_write(s->rx_desc_addr,
                                  (uint8_t *)s->rx_desc, sizeof(s->rx_desc));

        /* Next descriptor */
        if (rx_desc_get_wrap(s->rx_desc)) {
            DB_PRINT("wrapping RX descriptor list\n");
            s->rx_desc_addr = s->regs[GEM_RXQBASE];
        } else {
            DB_PRINT("incrementing RX descriptor list\n");
            s->rx_desc_addr += 8;
        }
        gem_get_rx_desc(s);
    }

    /* Count it */
    gem_receive_updatestats(s, buf, size);

    s->regs[GEM_RXSTATUS] |= GEM_RXSTATUS_FRMRCVD;
    s->regs[GEM_ISR] |= GEM_INT_RXCMPL & ~(s->regs[GEM_IMR]);

    /* Handle interrupt consequences */
    gem_update_int_status(s);

    return size;
}

/*
 * gem_transmit_updatestats:
 * Increment transmit statistics.
 */
static void gem_transmit_updatestats(CadenceGEMState *s, const uint8_t *packet,
                                     unsigned bytes)
{
    uint64_t octets;

    /* Total octets (bytes) transmitted */
    octets = ((uint64_t)(s->regs[GEM_OCTTXLO]) << 32) |
             s->regs[GEM_OCTTXHI];
    octets += bytes;
    s->regs[GEM_OCTTXLO] = octets >> 32;
    s->regs[GEM_OCTTXHI] = octets;

    /* Error-free Frames transmitted */
    s->regs[GEM_TXCNT]++;

    /* Error-free Broadcast Frames counter */
    if (!memcmp(packet, broadcast_addr, 6)) {
        s->regs[GEM_TXBCNT]++;
    }

    /* Error-free Multicast Frames counter */
    if (packet[0] == 0x01) {
        s->regs[GEM_TXMCNT]++;
    }

    if (bytes <= 64) {
        s->regs[GEM_TX64CNT]++;
    } else if (bytes <= 127) {
        s->regs[GEM_TX65CNT]++;
    } else if (bytes <= 255) {
        s->regs[GEM_TX128CNT]++;
    } else if (bytes <= 511) {
        s->regs[GEM_TX256CNT]++;
    } else if (bytes <= 1023) {
        s->regs[GEM_TX512CNT]++;
    } else if (bytes <= 1518) {
        s->regs[GEM_TX1024CNT]++;
    } else {
        s->regs[GEM_TX1519CNT]++;
    }
}

/*
 * gem_transmit:
 * Fish packets out of the descriptor ring and feed them to QEMU
 */
static void gem_transmit(CadenceGEMState *s)
{
    unsigned    desc[2];
    hwaddr packet_desc_addr;
    uint8_t     tx_packet[2048];
    uint8_t     *p;
    unsigned    total_bytes;

    /* Do nothing if transmit is not enabled. */
    if (!(s->regs[GEM_NWCTRL] & GEM_NWCTRL_TXENA)) {
        return;
    }

    DB_PRINT("\n");

    /* The packet we will hand off to QEMU.
     * Packets scattered across multiple descriptors are gathered to this
     * one contiguous buffer first.
     */
    p = tx_packet;
    total_bytes = 0;

    /* read current descriptor */
    packet_desc_addr = s->tx_desc_addr;

    DB_PRINT("read descriptor 0x%" HWADDR_PRIx "\n", packet_desc_addr);
    cpu_physical_memory_read(packet_desc_addr,
                             (uint8_t *)desc, sizeof(desc));
    /* Handle all descriptors owned by hardware */
    while (tx_desc_get_used(desc) == 0) {

        /* Do nothing if transmit is not enabled. */
        if (!(s->regs[GEM_NWCTRL] & GEM_NWCTRL_TXENA)) {
            return;
        }
        print_gem_tx_desc(desc);

        /* The real hardware would eat this (and possibly crash).
         * For QEMU let's lend a helping hand.
         */
        if ((tx_desc_get_buffer(desc) == 0) ||
            (tx_desc_get_length(desc) == 0)) {
            DB_PRINT("Invalid TX descriptor @ 0x%x\n",
                     (unsigned)packet_desc_addr);
            break;
        }

        if (tx_desc_get_length(desc) > sizeof(tx_packet) - (p - tx_packet)) {
            DB_PRINT("TX descriptor @ 0x%x too large: size 0x%x space 0x%x\n",
                     (unsigned)packet_desc_addr,
                     (unsigned)tx_desc_get_length(desc),
                     sizeof(tx_packet) - (p - tx_packet));
            break;
        }

        /* Gather this fragment of the packet from "dma memory" to our contig.
         * buffer.
         */
        cpu_physical_memory_read(tx_desc_get_buffer(desc), p,
                                 tx_desc_get_length(desc));
        p += tx_desc_get_length(desc);
        total_bytes += tx_desc_get_length(desc);

        /* Last descriptor for this packet; hand the whole thing off */
        if (tx_desc_get_last(desc)) {
            unsigned    desc_first[2];

            /* Modify the 1st descriptor of this packet to be owned by
             * the processor.
             */
            cpu_physical_memory_read(s->tx_desc_addr, (uint8_t *)desc_first,
                                     sizeof(desc_first));
            tx_desc_set_used(desc_first);
            cpu_physical_memory_write(s->tx_desc_addr, (uint8_t *)desc_first,
                                      sizeof(desc_first));
            /* Advance the hardware current descriptor past this packet */
            if (tx_desc_get_wrap(desc)) {
                s->tx_desc_addr = s->regs[GEM_TXQBASE];
            } else {
                s->tx_desc_addr = packet_desc_addr + 8;
            }
            DB_PRINT("TX descriptor next: 0x%08x\n", s->tx_desc_addr);

            s->regs[GEM_TXSTATUS] |= GEM_TXSTATUS_TXCMPL;
            s->regs[GEM_ISR] |= GEM_INT_TXCMPL & ~(s->regs[GEM_IMR]);

            /* Handle interrupt consequences */
            gem_update_int_status(s);

            /* Is checksum offload enabled? */
            if (s->regs[GEM_DMACFG] & GEM_DMACFG_TXCSUM_OFFL) {
                net_checksum_calculate(tx_packet, total_bytes);
            }

            /* Update MAC statistics */
            gem_transmit_updatestats(s, tx_packet, total_bytes);

            /* Send the packet somewhere */
            if (s->phy_loop || (s->regs[GEM_NWCTRL] & GEM_NWCTRL_LOCALLOOP)) {
                gem_receive(qemu_get_queue(s->nic), tx_packet, total_bytes);
            } else {
                qemu_send_packet(qemu_get_queue(s->nic), tx_packet,
                                 total_bytes);
            }

            /* Prepare for next packet */
            p = tx_packet;
            total_bytes = 0;
        }

        /* read next descriptor */
        if (tx_desc_get_wrap(desc)) {
            tx_desc_set_last(desc);
            packet_desc_addr = s->regs[GEM_TXQBASE];
        } else {
            packet_desc_addr += 8;
        }
        DB_PRINT("read descriptor 0x%" HWADDR_PRIx "\n", packet_desc_addr);
        cpu_physical_memory_read(packet_desc_addr,
                                 (uint8_t *)desc, sizeof(desc));
    }

    if (tx_desc_get_used(desc)) {
        s->regs[GEM_TXSTATUS] |= GEM_TXSTATUS_USED;
        s->regs[GEM_ISR] |= GEM_INT_TXUSED & ~(s->regs[GEM_IMR]);
        gem_update_int_status(s);
    }
}

static void gem_phy_reset(CadenceGEMState *s)
{
    memset(&s->phy_regs[0], 0, sizeof(s->phy_regs));
    s->phy_regs[PHY_REG_CONTROL] = 0x1140;
    s->phy_regs[PHY_REG_STATUS] = 0x7969;
    s->phy_regs[PHY_REG_PHYID1] = 0x0141;
    s->phy_regs[PHY_REG_PHYID2] = 0x0CC2;
    s->phy_regs[PHY_REG_ANEGADV] = 0x01E1;
    s->phy_regs[PHY_REG_LINKPABIL] = 0xCDE1;
    s->phy_regs[PHY_REG_ANEGEXP] = 0x000F;
    s->phy_regs[PHY_REG_NEXTP] = 0x2001;
    s->phy_regs[PHY_REG_LINKPNEXTP] = 0x40E6;
    s->phy_regs[PHY_REG_100BTCTRL] = 0x0300;
    s->phy_regs[PHY_REG_1000BTSTAT] = 0x7C00;
    s->phy_regs[PHY_REG_EXTSTAT] = 0x3000;
    s->phy_regs[PHY_REG_PHYSPCFC_CTL] = 0x0078;
    s->phy_regs[PHY_REG_PHYSPCFC_ST] = 0x7C00;
    s->phy_regs[PHY_REG_EXT_PHYSPCFC_CTL] = 0x0C60;
    s->phy_regs[PHY_REG_LED] = 0x4100;
    s->phy_regs[PHY_REG_EXT_PHYSPCFC_CTL2] = 0x000A;
    s->phy_regs[PHY_REG_EXT_PHYSPCFC_ST] = 0x848B;

    phy_update_link(s);
}

static void gem_reset(DeviceState *d)
{
    int i;
    CadenceGEMState *s = CADENCE_GEM(d);
    const uint8_t *a;

    DB_PRINT("\n");

    /* Set post reset register values */
    memset(&s->regs[0], 0, sizeof(s->regs));
    s->regs[GEM_NWCFG] = 0x00080000;
    s->regs[GEM_NWSTATUS] = 0x00000006;
    s->regs[GEM_DMACFG] = 0x00020784;
    s->regs[GEM_IMR] = 0x07ffffff;
    s->regs[GEM_TXPAUSE] = 0x0000ffff;
    s->regs[GEM_TXPARTIALSF] = 0x000003ff;
    s->regs[GEM_RXPARTIALSF] = 0x000003ff;
    s->regs[GEM_MODID] = 0x00020118;
    s->regs[GEM_DESCONF] = 0x02500111;
    s->regs[GEM_DESCONF2] = 0x2ab13fff;
    s->regs[GEM_DESCONF5] = 0x002f2145;
    s->regs[GEM_DESCONF6] = 0x00000200;

    /* Set MAC address */
    a = &s->conf.macaddr.a[0];
    s->regs[GEM_SPADDR1LO] = a[0] | (a[1] << 8) | (a[2] << 16) | (a[3] << 24);
    s->regs[GEM_SPADDR1HI] = a[4] | (a[5] << 8);

    for (i = 0; i < 4; i++) {
        s->sar_active[i] = false;
    }

    gem_phy_reset(s);

    gem_update_int_status(s);
}

static uint16_t gem_phy_read(CadenceGEMState *s, unsigned reg_num)
{
    DB_PRINT("reg: %d value: 0x%04x\n", reg_num, s->phy_regs[reg_num]);
    return s->phy_regs[reg_num];
}

static void gem_phy_write(CadenceGEMState *s, unsigned reg_num, uint16_t val)
{
    DB_PRINT("reg: %d value: 0x%04x\n", reg_num, val);

    switch (reg_num) {
    case PHY_REG_CONTROL:
        if (val & PHY_REG_CONTROL_RST) {
            /* Phy reset */
            gem_phy_reset(s);
            val &= ~(PHY_REG_CONTROL_RST | PHY_REG_CONTROL_LOOP);
            s->phy_loop = 0;
        }
        if (val & PHY_REG_CONTROL_ANEG) {
            /* Complete autonegotiation immediately */
            val &= ~PHY_REG_CONTROL_ANEG;
            s->phy_regs[PHY_REG_STATUS] |= PHY_REG_STATUS_ANEGCMPL;
        }
        if (val & PHY_REG_CONTROL_LOOP) {
            DB_PRINT("PHY placed in loopback\n");
            s->phy_loop = 1;
        } else {
            s->phy_loop = 0;
        }
        break;
    }
    s->phy_regs[reg_num] = val;
}

/*
 * gem_read32:
 * Read a GEM register.
 */
static uint64_t gem_read(void *opaque, hwaddr offset, unsigned size)
{
    CadenceGEMState *s;
    uint32_t retval;

    s = (CadenceGEMState *)opaque;

    offset >>= 2;
    retval = s->regs[offset];

    DB_PRINT("offset: 0x%04x read: 0x%08x\n", (unsigned)offset*4, retval);

    switch (offset) {
    case GEM_ISR:
        DB_PRINT("lowering irq on ISR read\n");
        qemu_set_irq(s->irq, 0);
        break;
    case GEM_PHYMNTNC:
        if (retval & GEM_PHYMNTNC_OP_R) {
            uint32_t phy_addr, reg_num;

            phy_addr = (retval & GEM_PHYMNTNC_ADDR) >> GEM_PHYMNTNC_ADDR_SHFT;
            if (phy_addr == BOARD_PHY_ADDRESS || phy_addr == 0) {
                reg_num = (retval & GEM_PHYMNTNC_REG) >> GEM_PHYMNTNC_REG_SHIFT;
                retval &= 0xFFFF0000;
                retval |= gem_phy_read(s, reg_num);
            } else {
                retval |= 0xFFFF; /* No device at this address */
            }
        }
        break;
    }

    /* Squash read to clear bits */
    s->regs[offset] &= ~(s->regs_rtc[offset]);

    /* Do not provide write only bits */
    retval &= ~(s->regs_wo[offset]);

    DB_PRINT("0x%08x\n", retval);
    return retval;
}

/*
 * gem_write32:
 * Write a GEM register.
 */
static void gem_write(void *opaque, hwaddr offset, uint64_t val,
        unsigned size)
{
    CadenceGEMState *s = (CadenceGEMState *)opaque;
    uint32_t readonly;

    DB_PRINT("offset: 0x%04x write: 0x%08x ", (unsigned)offset, (unsigned)val);
    offset >>= 2;

    /* Squash bits which are read only in write value */
    val &= ~(s->regs_ro[offset]);
    /* Preserve (only) bits which are read only and wtc in register */
    readonly = s->regs[offset] & (s->regs_ro[offset] | s->regs_w1c[offset]);

    /* Copy register write to backing store */
    s->regs[offset] = (val & ~s->regs_w1c[offset]) | readonly;

    /* do w1c */
    s->regs[offset] &= ~(s->regs_w1c[offset] & val);

    /* Handle register write side effects */
    switch (offset) {
    case GEM_NWCTRL:
        if (val & GEM_NWCTRL_RXENA) {
            gem_get_rx_desc(s);
        }
        if (val & GEM_NWCTRL_TXSTART) {
            gem_transmit(s);
        }
        if (!(val & GEM_NWCTRL_TXENA)) {
            /* Reset to start of Q when transmit disabled. */
            s->tx_desc_addr = s->regs[GEM_TXQBASE];
        }
        if (gem_can_receive(qemu_get_queue(s->nic))) {
            qemu_flush_queued_packets(qemu_get_queue(s->nic));
        }
        break;

    case GEM_TXSTATUS:
        gem_update_int_status(s);
        break;
    case GEM_RXQBASE:
        s->rx_desc_addr = val;
        break;
    case GEM_TXQBASE:
        s->tx_desc_addr = val;
        break;
    case GEM_RXSTATUS:
        gem_update_int_status(s);
        break;
    case GEM_IER:
        s->regs[GEM_IMR] &= ~val;
        gem_update_int_status(s);
        break;
    case GEM_IDR:
        s->regs[GEM_IMR] |= val;
        gem_update_int_status(s);
        break;
    case GEM_SPADDR1LO:
    case GEM_SPADDR2LO:
    case GEM_SPADDR3LO:
    case GEM_SPADDR4LO:
        s->sar_active[(offset - GEM_SPADDR1LO) / 2] = false;
        break;
    case GEM_SPADDR1HI:
    case GEM_SPADDR2HI:
    case GEM_SPADDR3HI:
    case GEM_SPADDR4HI:
        s->sar_active[(offset - GEM_SPADDR1HI) / 2] = true;
        break;
    case GEM_PHYMNTNC:
        if (val & GEM_PHYMNTNC_OP_W) {
            uint32_t phy_addr, reg_num;

            phy_addr = (val & GEM_PHYMNTNC_ADDR) >> GEM_PHYMNTNC_ADDR_SHFT;
            if (phy_addr == BOARD_PHY_ADDRESS || phy_addr == 0) {
                reg_num = (val & GEM_PHYMNTNC_REG) >> GEM_PHYMNTNC_REG_SHIFT;
                gem_phy_write(s, reg_num, val);
            }
        }
        break;
    }

    DB_PRINT("newval: 0x%08x\n", s->regs[offset]);
}

static const MemoryRegionOps gem_ops = {
    .read = gem_read,
    .write = gem_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
};

static void gem_set_link(NetClientState *nc)
{
    DB_PRINT("\n");
    phy_update_link(qemu_get_nic_opaque(nc));
}

static NetClientInfo net_gem_info = {
    .type = NET_CLIENT_OPTIONS_KIND_NIC,
    .size = sizeof(NICState),
    .can_receive = gem_can_receive,
    .receive = gem_receive,
    .link_status_changed = gem_set_link,
};

static int gem_init(SysBusDevice *sbd)
{
    DeviceState *dev = DEVICE(sbd);
    CadenceGEMState *s = CADENCE_GEM(dev);

    DB_PRINT("\n");

    gem_init_register_masks(s);
    memory_region_init_io(&s->iomem, OBJECT(s), &gem_ops, s,
                          "enet", sizeof(s->regs));
    sysbus_init_mmio(sbd, &s->iomem);
    sysbus_init_irq(sbd, &s->irq);
    qemu_macaddr_default_if_unset(&s->conf.macaddr);

    s->nic = qemu_new_nic(&net_gem_info, &s->conf,
            object_get_typename(OBJECT(dev)), dev->id, s);

    return 0;
}

static const VMStateDescription vmstate_cadence_gem = {
    .name = "cadence_gem",
    .version_id = 2,
    .minimum_version_id = 2,
    .fields = (VMStateField[]) {
        VMSTATE_UINT32_ARRAY(regs, CadenceGEMState, CADENCE_GEM_MAXREG),
        VMSTATE_UINT16_ARRAY(phy_regs, CadenceGEMState, 32),
        VMSTATE_UINT8(phy_loop, CadenceGEMState),
        VMSTATE_UINT32(rx_desc_addr, CadenceGEMState),
        VMSTATE_UINT32(tx_desc_addr, CadenceGEMState),
        VMSTATE_BOOL_ARRAY(sar_active, CadenceGEMState, 4),
        VMSTATE_END_OF_LIST(),
    }
};

static Property gem_properties[] = {
    DEFINE_NIC_PROPERTIES(CadenceGEMState, conf),
    DEFINE_PROP_END_OF_LIST(),
};

static void gem_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);

    sdc->init = gem_init;
    dc->props = gem_properties;
    dc->vmsd = &vmstate_cadence_gem;
    dc->reset = gem_reset;
}

static const TypeInfo gem_info = {
    .name  = TYPE_CADENCE_GEM,
    .parent = TYPE_SYS_BUS_DEVICE,
    .instance_size  = sizeof(CadenceGEMState),
    .class_init = gem_class_init,
};

static void gem_register_types(void)
{
    type_register_static(&gem_info);
}

type_init(gem_register_types)