aboutsummaryrefslogtreecommitdiff
path: root/hw/net/dp8393x.c
blob: a5678e11faf9e20e972df205b2bff0e7c2ac89d4 (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
/*
 * QEMU NS SONIC DP8393x netcard
 *
 * Copyright (c) 2008-2009 Herve Poussineau
 *
 * 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 of
 * the License, 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; if not, see <http://www.gnu.org/licenses/>.
 */

#include "qemu/osdep.h"
#include "hw/irq.h"
#include "hw/qdev-properties.h"
#include "hw/sysbus.h"
#include "migration/vmstate.h"
#include "net/net.h"
#include "qapi/error.h"
#include "qemu/module.h"
#include "qemu/timer.h"
#include <zlib.h>

//#define DEBUG_SONIC

#define SONIC_PROM_SIZE 0x1000

#ifdef DEBUG_SONIC
#define DPRINTF(fmt, ...) \
do { printf("sonic: " fmt , ##  __VA_ARGS__); } while (0)
static const char* reg_names[] = {
    "CR", "DCR", "RCR", "TCR", "IMR", "ISR", "UTDA", "CTDA",
    "TPS", "TFC", "TSA0", "TSA1", "TFS", "URDA", "CRDA", "CRBA0",
    "CRBA1", "RBWC0", "RBWC1", "EOBC", "URRA", "RSA", "REA", "RRP",
    "RWP", "TRBA0", "TRBA1", "0x1b", "0x1c", "0x1d", "0x1e", "LLFA",
    "TTDA", "CEP", "CAP2", "CAP1", "CAP0", "CE", "CDP", "CDC",
    "SR", "WT0", "WT1", "RSC", "CRCT", "FAET", "MPT", "MDT",
    "0x30", "0x31", "0x32", "0x33", "0x34", "0x35", "0x36", "0x37",
    "0x38", "0x39", "0x3a", "0x3b", "0x3c", "0x3d", "0x3e", "DCR2" };
#else
#define DPRINTF(fmt, ...) do {} while (0)
#endif

#define SONIC_ERROR(fmt, ...) \
do { printf("sonic ERROR: %s: " fmt, __func__ , ## __VA_ARGS__); } while (0)

#define SONIC_CR     0x00
#define SONIC_DCR    0x01
#define SONIC_RCR    0x02
#define SONIC_TCR    0x03
#define SONIC_IMR    0x04
#define SONIC_ISR    0x05
#define SONIC_UTDA   0x06
#define SONIC_CTDA   0x07
#define SONIC_TPS    0x08
#define SONIC_TFC    0x09
#define SONIC_TSA0   0x0a
#define SONIC_TSA1   0x0b
#define SONIC_TFS    0x0c
#define SONIC_URDA   0x0d
#define SONIC_CRDA   0x0e
#define SONIC_CRBA0  0x0f
#define SONIC_CRBA1  0x10
#define SONIC_RBWC0  0x11
#define SONIC_RBWC1  0x12
#define SONIC_EOBC   0x13
#define SONIC_URRA   0x14
#define SONIC_RSA    0x15
#define SONIC_REA    0x16
#define SONIC_RRP    0x17
#define SONIC_RWP    0x18
#define SONIC_TRBA0  0x19
#define SONIC_TRBA1  0x1a
#define SONIC_LLFA   0x1f
#define SONIC_TTDA   0x20
#define SONIC_CEP    0x21
#define SONIC_CAP2   0x22
#define SONIC_CAP1   0x23
#define SONIC_CAP0   0x24
#define SONIC_CE     0x25
#define SONIC_CDP    0x26
#define SONIC_CDC    0x27
#define SONIC_SR     0x28
#define SONIC_WT0    0x29
#define SONIC_WT1    0x2a
#define SONIC_RSC    0x2b
#define SONIC_CRCT   0x2c
#define SONIC_FAET   0x2d
#define SONIC_MPT    0x2e
#define SONIC_MDT    0x2f
#define SONIC_DCR2   0x3f

#define SONIC_CR_HTX     0x0001
#define SONIC_CR_TXP     0x0002
#define SONIC_CR_RXDIS   0x0004
#define SONIC_CR_RXEN    0x0008
#define SONIC_CR_STP     0x0010
#define SONIC_CR_ST      0x0020
#define SONIC_CR_RST     0x0080
#define SONIC_CR_RRRA    0x0100
#define SONIC_CR_LCAM    0x0200
#define SONIC_CR_MASK    0x03bf

#define SONIC_DCR_DW     0x0020
#define SONIC_DCR_LBR    0x2000
#define SONIC_DCR_EXBUS  0x8000

#define SONIC_RCR_PRX    0x0001
#define SONIC_RCR_LBK    0x0002
#define SONIC_RCR_FAER   0x0004
#define SONIC_RCR_CRCR   0x0008
#define SONIC_RCR_CRS    0x0020
#define SONIC_RCR_LPKT   0x0040
#define SONIC_RCR_BC     0x0080
#define SONIC_RCR_MC     0x0100
#define SONIC_RCR_LB0    0x0200
#define SONIC_RCR_LB1    0x0400
#define SONIC_RCR_AMC    0x0800
#define SONIC_RCR_PRO    0x1000
#define SONIC_RCR_BRD    0x2000
#define SONIC_RCR_RNT    0x4000

#define SONIC_TCR_PTX    0x0001
#define SONIC_TCR_BCM    0x0002
#define SONIC_TCR_FU     0x0004
#define SONIC_TCR_EXC    0x0040
#define SONIC_TCR_CRSL   0x0080
#define SONIC_TCR_NCRS   0x0100
#define SONIC_TCR_EXD    0x0400
#define SONIC_TCR_CRCI   0x2000
#define SONIC_TCR_PINT   0x8000

#define SONIC_ISR_RBE    0x0020
#define SONIC_ISR_RDE    0x0040
#define SONIC_ISR_TC     0x0080
#define SONIC_ISR_TXDN   0x0200
#define SONIC_ISR_PKTRX  0x0400
#define SONIC_ISR_PINT   0x0800
#define SONIC_ISR_LCD    0x1000

#define TYPE_DP8393X "dp8393x"
#define DP8393X(obj) OBJECT_CHECK(dp8393xState, (obj), TYPE_DP8393X)

typedef struct dp8393xState {
    SysBusDevice parent_obj;

    /* Hardware */
    uint8_t it_shift;
    qemu_irq irq;
#ifdef DEBUG_SONIC
    int irq_level;
#endif
    QEMUTimer *watchdog;
    int64_t wt_last_update;
    NICConf conf;
    NICState *nic;
    MemoryRegion mmio;
    MemoryRegion prom;

    /* Registers */
    uint8_t cam[16][6];
    uint16_t regs[0x40];

    /* Temporaries */
    uint8_t tx_buffer[0x10000];
    int loopback_packet;

    /* Memory access */
    void *dma_mr;
    AddressSpace as;
} dp8393xState;

/* Accessor functions for values which are formed by
 * concatenating two 16 bit device registers. By putting these
 * in their own functions with a uint32_t return type we avoid the
 * pitfall of implicit sign extension where ((x << 16) | y) is a
 * signed 32 bit integer that might get sign-extended to a 64 bit integer.
 */
static uint32_t dp8393x_cdp(dp8393xState *s)
{
    return (s->regs[SONIC_URRA] << 16) | s->regs[SONIC_CDP];
}

static uint32_t dp8393x_crba(dp8393xState *s)
{
    return (s->regs[SONIC_CRBA1] << 16) | s->regs[SONIC_CRBA0];
}

static uint32_t dp8393x_crda(dp8393xState *s)
{
    return (s->regs[SONIC_URDA] << 16) | s->regs[SONIC_CRDA];
}

static uint32_t dp8393x_rbwc(dp8393xState *s)
{
    return (s->regs[SONIC_RBWC1] << 16) | s->regs[SONIC_RBWC0];
}

static uint32_t dp8393x_rrp(dp8393xState *s)
{
    return (s->regs[SONIC_URRA] << 16) | s->regs[SONIC_RRP];
}

static uint32_t dp8393x_tsa(dp8393xState *s)
{
    return (s->regs[SONIC_TSA1] << 16) | s->regs[SONIC_TSA0];
}

static uint32_t dp8393x_ttda(dp8393xState *s)
{
    return (s->regs[SONIC_UTDA] << 16) | s->regs[SONIC_TTDA];
}

static uint32_t dp8393x_wt(dp8393xState *s)
{
    return s->regs[SONIC_WT1] << 16 | s->regs[SONIC_WT0];
}

static void dp8393x_update_irq(dp8393xState *s)
{
    int level = (s->regs[SONIC_IMR] & s->regs[SONIC_ISR]) ? 1 : 0;

#ifdef DEBUG_SONIC
    if (level != s->irq_level) {
        s->irq_level = level;
        if (level) {
            DPRINTF("raise irq, isr is 0x%04x\n", s->regs[SONIC_ISR]);
        } else {
            DPRINTF("lower irq\n");
        }
    }
#endif

    qemu_set_irq(s->irq, level);
}

static void dp8393x_do_load_cam(dp8393xState *s)
{
    uint16_t data[8];
    int width, size;
    uint16_t index = 0;

    width = (s->regs[SONIC_DCR] & SONIC_DCR_DW) ? 2 : 1;
    size = sizeof(uint16_t) * 4 * width;

    while (s->regs[SONIC_CDC] & 0x1f) {
        /* Fill current entry */
        address_space_rw(&s->as, dp8393x_cdp(s),
            MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
        s->cam[index][0] = data[1 * width] & 0xff;
        s->cam[index][1] = data[1 * width] >> 8;
        s->cam[index][2] = data[2 * width] & 0xff;
        s->cam[index][3] = data[2 * width] >> 8;
        s->cam[index][4] = data[3 * width] & 0xff;
        s->cam[index][5] = data[3 * width] >> 8;
        DPRINTF("load cam[%d] with %02x%02x%02x%02x%02x%02x\n", index,
            s->cam[index][0], s->cam[index][1], s->cam[index][2],
            s->cam[index][3], s->cam[index][4], s->cam[index][5]);
        /* Move to next entry */
        s->regs[SONIC_CDC]--;
        s->regs[SONIC_CDP] += size;
        index++;
    }

    /* Read CAM enable */
    address_space_rw(&s->as, dp8393x_cdp(s),
        MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
    s->regs[SONIC_CE] = data[0 * width];
    DPRINTF("load cam done. cam enable mask 0x%04x\n", s->regs[SONIC_CE]);

    /* Done */
    s->regs[SONIC_CR] &= ~SONIC_CR_LCAM;
    s->regs[SONIC_ISR] |= SONIC_ISR_LCD;
    dp8393x_update_irq(s);
}

static void dp8393x_do_read_rra(dp8393xState *s)
{
    uint16_t data[8];
    int width, size;

    /* Read memory */
    width = (s->regs[SONIC_DCR] & SONIC_DCR_DW) ? 2 : 1;
    size = sizeof(uint16_t) * 4 * width;
    address_space_rw(&s->as, dp8393x_rrp(s),
        MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);

    /* Update SONIC registers */
    s->regs[SONIC_CRBA0] = data[0 * width];
    s->regs[SONIC_CRBA1] = data[1 * width];
    s->regs[SONIC_RBWC0] = data[2 * width];
    s->regs[SONIC_RBWC1] = data[3 * width];
    DPRINTF("CRBA0/1: 0x%04x/0x%04x, RBWC0/1: 0x%04x/0x%04x\n",
        s->regs[SONIC_CRBA0], s->regs[SONIC_CRBA1],
        s->regs[SONIC_RBWC0], s->regs[SONIC_RBWC1]);

    /* Go to next entry */
    s->regs[SONIC_RRP] += size;

    /* Handle wrap */
    if (s->regs[SONIC_RRP] == s->regs[SONIC_REA]) {
        s->regs[SONIC_RRP] = s->regs[SONIC_RSA];
    }

    /* Check resource exhaustion */
    if (s->regs[SONIC_RRP] == s->regs[SONIC_RWP])
    {
        s->regs[SONIC_ISR] |= SONIC_ISR_RBE;
        dp8393x_update_irq(s);
    }

    /* Done */
    s->regs[SONIC_CR] &= ~SONIC_CR_RRRA;
}

static void dp8393x_do_software_reset(dp8393xState *s)
{
    timer_del(s->watchdog);

    s->regs[SONIC_CR] &= ~(SONIC_CR_LCAM | SONIC_CR_RRRA | SONIC_CR_TXP | SONIC_CR_HTX);
    s->regs[SONIC_CR] |= SONIC_CR_RST | SONIC_CR_RXDIS;
}

static void dp8393x_set_next_tick(dp8393xState *s)
{
    uint32_t ticks;
    int64_t delay;

    if (s->regs[SONIC_CR] & SONIC_CR_STP) {
        timer_del(s->watchdog);
        return;
    }

    ticks = dp8393x_wt(s);
    s->wt_last_update = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
    delay = NANOSECONDS_PER_SECOND * ticks / 5000000;
    timer_mod(s->watchdog, s->wt_last_update + delay);
}

static void dp8393x_update_wt_regs(dp8393xState *s)
{
    int64_t elapsed;
    uint32_t val;

    if (s->regs[SONIC_CR] & SONIC_CR_STP) {
        timer_del(s->watchdog);
        return;
    }

    elapsed = s->wt_last_update - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
    val = dp8393x_wt(s);
    val -= elapsed / 5000000;
    s->regs[SONIC_WT1] = (val >> 16) & 0xffff;
    s->regs[SONIC_WT0] = (val >> 0)  & 0xffff;
    dp8393x_set_next_tick(s);

}

static void dp8393x_do_start_timer(dp8393xState *s)
{
    s->regs[SONIC_CR] &= ~SONIC_CR_STP;
    dp8393x_set_next_tick(s);
}

static void dp8393x_do_stop_timer(dp8393xState *s)
{
    s->regs[SONIC_CR] &= ~SONIC_CR_ST;
    dp8393x_update_wt_regs(s);
}

static int dp8393x_can_receive(NetClientState *nc);

static void dp8393x_do_receiver_enable(dp8393xState *s)
{
    s->regs[SONIC_CR] &= ~SONIC_CR_RXDIS;
    if (dp8393x_can_receive(s->nic->ncs)) {
        qemu_flush_queued_packets(qemu_get_queue(s->nic));
    }
}

static void dp8393x_do_receiver_disable(dp8393xState *s)
{
    s->regs[SONIC_CR] &= ~SONIC_CR_RXEN;
}

static void dp8393x_do_transmit_packets(dp8393xState *s)
{
    NetClientState *nc = qemu_get_queue(s->nic);
    uint16_t data[12];
    int width, size;
    int tx_len, len;
    uint16_t i;

    width = (s->regs[SONIC_DCR] & SONIC_DCR_DW) ? 2 : 1;

    while (1) {
        /* Read memory */
        size = sizeof(uint16_t) * 6 * width;
        s->regs[SONIC_TTDA] = s->regs[SONIC_CTDA];
        DPRINTF("Transmit packet at %08x\n", dp8393x_ttda(s));
        address_space_rw(&s->as,
            dp8393x_ttda(s) + sizeof(uint16_t) * width,
            MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
        tx_len = 0;

        /* Update registers */
        s->regs[SONIC_TCR] = data[0 * width] & 0xf000;
        s->regs[SONIC_TPS] = data[1 * width];
        s->regs[SONIC_TFC] = data[2 * width];
        s->regs[SONIC_TSA0] = data[3 * width];
        s->regs[SONIC_TSA1] = data[4 * width];
        s->regs[SONIC_TFS] = data[5 * width];

        /* Handle programmable interrupt */
        if (s->regs[SONIC_TCR] & SONIC_TCR_PINT) {
            s->regs[SONIC_ISR] |= SONIC_ISR_PINT;
        } else {
            s->regs[SONIC_ISR] &= ~SONIC_ISR_PINT;
        }

        for (i = 0; i < s->regs[SONIC_TFC]; ) {
            /* Append fragment */
            len = s->regs[SONIC_TFS];
            if (tx_len + len > sizeof(s->tx_buffer)) {
                len = sizeof(s->tx_buffer) - tx_len;
            }
            address_space_rw(&s->as, dp8393x_tsa(s),
                MEMTXATTRS_UNSPECIFIED, &s->tx_buffer[tx_len], len, 0);
            tx_len += len;

            i++;
            if (i != s->regs[SONIC_TFC]) {
                /* Read next fragment details */
                size = sizeof(uint16_t) * 3 * width;
                address_space_rw(&s->as,
                    dp8393x_ttda(s) + sizeof(uint16_t) * (4 + 3 * i) * width,
                    MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
                s->regs[SONIC_TSA0] = data[0 * width];
                s->regs[SONIC_TSA1] = data[1 * width];
                s->regs[SONIC_TFS] = data[2 * width];
            }
        }

        /* Handle Ethernet checksum */
        if (!(s->regs[SONIC_TCR] & SONIC_TCR_CRCI)) {
            /* Don't append FCS there, to look like slirp packets
             * which don't have one */
        } else {
            /* Remove existing FCS */
            tx_len -= 4;
        }

        if (s->regs[SONIC_RCR] & (SONIC_RCR_LB1 | SONIC_RCR_LB0)) {
            /* Loopback */
            s->regs[SONIC_TCR] |= SONIC_TCR_CRSL;
            if (nc->info->can_receive(nc)) {
                s->loopback_packet = 1;
                nc->info->receive(nc, s->tx_buffer, tx_len);
            }
        } else {
            /* Transmit packet */
            qemu_send_packet(nc, s->tx_buffer, tx_len);
        }
        s->regs[SONIC_TCR] |= SONIC_TCR_PTX;

        /* Write status */
        data[0 * width] = s->regs[SONIC_TCR] & 0x0fff; /* status */
        size = sizeof(uint16_t) * width;
        address_space_rw(&s->as,
            dp8393x_ttda(s),
            MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 1);

        if (!(s->regs[SONIC_CR] & SONIC_CR_HTX)) {
            /* Read footer of packet */
            size = sizeof(uint16_t) * width;
            address_space_rw(&s->as,
                dp8393x_ttda(s) +
                             sizeof(uint16_t) *
                             (4 + 3 * s->regs[SONIC_TFC]) * width,
                MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
            s->regs[SONIC_CTDA] = data[0 * width] & ~0x1;
            if (data[0 * width] & 0x1) {
                /* EOL detected */
                break;
            }
        }
    }

    /* Done */
    s->regs[SONIC_CR] &= ~SONIC_CR_TXP;
    s->regs[SONIC_ISR] |= SONIC_ISR_TXDN;
    dp8393x_update_irq(s);
}

static void dp8393x_do_halt_transmission(dp8393xState *s)
{
    /* Nothing to do */
}

static void dp8393x_do_command(dp8393xState *s, uint16_t command)
{
    if ((s->regs[SONIC_CR] & SONIC_CR_RST) && !(command & SONIC_CR_RST)) {
        s->regs[SONIC_CR] &= ~SONIC_CR_RST;
        return;
    }

    s->regs[SONIC_CR] |= (command & SONIC_CR_MASK);

    if (command & SONIC_CR_HTX)
        dp8393x_do_halt_transmission(s);
    if (command & SONIC_CR_TXP)
        dp8393x_do_transmit_packets(s);
    if (command & SONIC_CR_RXDIS)
        dp8393x_do_receiver_disable(s);
    if (command & SONIC_CR_RXEN)
        dp8393x_do_receiver_enable(s);
    if (command & SONIC_CR_STP)
        dp8393x_do_stop_timer(s);
    if (command & SONIC_CR_ST)
        dp8393x_do_start_timer(s);
    if (command & SONIC_CR_RST)
        dp8393x_do_software_reset(s);
    if (command & SONIC_CR_RRRA)
        dp8393x_do_read_rra(s);
    if (command & SONIC_CR_LCAM)
        dp8393x_do_load_cam(s);
}

static uint64_t dp8393x_read(void *opaque, hwaddr addr, unsigned int size)
{
    dp8393xState *s = opaque;
    int reg = addr >> s->it_shift;
    uint16_t val = 0;

    switch (reg) {
        /* Update data before reading it */
        case SONIC_WT0:
        case SONIC_WT1:
            dp8393x_update_wt_regs(s);
            val = s->regs[reg];
            break;
        /* Accept read to some registers only when in reset mode */
        case SONIC_CAP2:
        case SONIC_CAP1:
        case SONIC_CAP0:
            if (s->regs[SONIC_CR] & SONIC_CR_RST) {
                val = s->cam[s->regs[SONIC_CEP] & 0xf][2* (SONIC_CAP0 - reg) + 1] << 8;
                val |= s->cam[s->regs[SONIC_CEP] & 0xf][2* (SONIC_CAP0 - reg)];
            }
            break;
        /* All other registers have no special contrainst */
        default:
            val = s->regs[reg];
    }

    DPRINTF("read 0x%04x from reg %s\n", val, reg_names[reg]);

    return val;
}

static void dp8393x_write(void *opaque, hwaddr addr, uint64_t data,
                          unsigned int size)
{
    dp8393xState *s = opaque;
    int reg = addr >> s->it_shift;

    DPRINTF("write 0x%04x to reg %s\n", (uint16_t)data, reg_names[reg]);

    switch (reg) {
        /* Command register */
        case SONIC_CR:
            dp8393x_do_command(s, data);
            break;
        /* Prevent write to read-only registers */
        case SONIC_CAP2:
        case SONIC_CAP1:
        case SONIC_CAP0:
        case SONIC_SR:
        case SONIC_MDT:
            DPRINTF("writing to reg %d invalid\n", reg);
            break;
        /* Accept write to some registers only when in reset mode */
        case SONIC_DCR:
            if (s->regs[SONIC_CR] & SONIC_CR_RST) {
                s->regs[reg] = data & 0xbfff;
            } else {
                DPRINTF("writing to DCR invalid\n");
            }
            break;
        case SONIC_DCR2:
            if (s->regs[SONIC_CR] & SONIC_CR_RST) {
                s->regs[reg] = data & 0xf017;
            } else {
                DPRINTF("writing to DCR2 invalid\n");
            }
            break;
        /* 12 lower bytes are Read Only */
        case SONIC_TCR:
            s->regs[reg] = data & 0xf000;
            break;
        /* 9 lower bytes are Read Only */
        case SONIC_RCR:
            s->regs[reg] = data & 0xffe0;
            break;
        /* Ignore most significant bit */
        case SONIC_IMR:
            s->regs[reg] = data & 0x7fff;
            dp8393x_update_irq(s);
            break;
        /* Clear bits by writing 1 to them */
        case SONIC_ISR:
            data &= s->regs[reg];
            s->regs[reg] &= ~data;
            if (data & SONIC_ISR_RBE) {
                dp8393x_do_read_rra(s);
            }
            dp8393x_update_irq(s);
            if (dp8393x_can_receive(s->nic->ncs)) {
                qemu_flush_queued_packets(qemu_get_queue(s->nic));
            }
            break;
        /* Ignore least significant bit */
        case SONIC_RSA:
        case SONIC_REA:
        case SONIC_RRP:
        case SONIC_RWP:
            s->regs[reg] = data & 0xfffe;
            break;
        /* Invert written value for some registers */
        case SONIC_CRCT:
        case SONIC_FAET:
        case SONIC_MPT:
            s->regs[reg] = data ^ 0xffff;
            break;
        /* All other registers have no special contrainst */
        default:
            s->regs[reg] = data;
    }

    if (reg == SONIC_WT0 || reg == SONIC_WT1) {
        dp8393x_set_next_tick(s);
    }
}

static const MemoryRegionOps dp8393x_ops = {
    .read = dp8393x_read,
    .write = dp8393x_write,
    .impl.min_access_size = 2,
    .impl.max_access_size = 2,
    .endianness = DEVICE_NATIVE_ENDIAN,
};

static void dp8393x_watchdog(void *opaque)
{
    dp8393xState *s = opaque;

    if (s->regs[SONIC_CR] & SONIC_CR_STP) {
        return;
    }

    s->regs[SONIC_WT1] = 0xffff;
    s->regs[SONIC_WT0] = 0xffff;
    dp8393x_set_next_tick(s);

    /* Signal underflow */
    s->regs[SONIC_ISR] |= SONIC_ISR_TC;
    dp8393x_update_irq(s);
}

static int dp8393x_can_receive(NetClientState *nc)
{
    dp8393xState *s = qemu_get_nic_opaque(nc);

    if (!(s->regs[SONIC_CR] & SONIC_CR_RXEN))
        return 0;
    if (s->regs[SONIC_ISR] & SONIC_ISR_RBE)
        return 0;
    return 1;
}

static int dp8393x_receive_filter(dp8393xState *s, const uint8_t * buf,
                                  int size)
{
    static const uint8_t bcast[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
    int i;

    /* Check promiscuous mode */
    if ((s->regs[SONIC_RCR] & SONIC_RCR_PRO) && (buf[0] & 1) == 0) {
        return 0;
    }

    /* Check multicast packets */
    if ((s->regs[SONIC_RCR] & SONIC_RCR_AMC) && (buf[0] & 1) == 1) {
        return SONIC_RCR_MC;
    }

    /* Check broadcast */
    if ((s->regs[SONIC_RCR] & SONIC_RCR_BRD) && !memcmp(buf, bcast, sizeof(bcast))) {
        return SONIC_RCR_BC;
    }

    /* Check CAM */
    for (i = 0; i < 16; i++) {
        if (s->regs[SONIC_CE] & (1 << i)) {
             /* Entry enabled */
             if (!memcmp(buf, s->cam[i], sizeof(s->cam[i]))) {
                 return 0;
             }
        }
    }

    return -1;
}

static ssize_t dp8393x_receive(NetClientState *nc, const uint8_t * buf,
                               size_t size)
{
    dp8393xState *s = qemu_get_nic_opaque(nc);
    uint16_t data[10];
    int packet_type;
    uint32_t available, address;
    int width, rx_len = size;
    uint32_t checksum;

    width = (s->regs[SONIC_DCR] & SONIC_DCR_DW) ? 2 : 1;

    s->regs[SONIC_RCR] &= ~(SONIC_RCR_PRX | SONIC_RCR_LBK | SONIC_RCR_FAER |
        SONIC_RCR_CRCR | SONIC_RCR_LPKT | SONIC_RCR_BC | SONIC_RCR_MC);

    packet_type = dp8393x_receive_filter(s, buf, size);
    if (packet_type < 0) {
        DPRINTF("packet not for netcard\n");
        return -1;
    }

    /* XXX: Check byte ordering */

    /* Check for EOL */
    if (s->regs[SONIC_LLFA] & 0x1) {
        /* Are we still in resource exhaustion? */
        size = sizeof(uint16_t) * 1 * width;
        address = dp8393x_crda(s) + sizeof(uint16_t) * 5 * width;
        address_space_rw(&s->as, address, MEMTXATTRS_UNSPECIFIED,
                         (uint8_t *)data, size, 0);
        if (data[0 * width] & 0x1) {
            /* Still EOL ; stop reception */
            return -1;
        } else {
            s->regs[SONIC_CRDA] = s->regs[SONIC_LLFA];
        }
    }

    /* Save current position */
    s->regs[SONIC_TRBA1] = s->regs[SONIC_CRBA1];
    s->regs[SONIC_TRBA0] = s->regs[SONIC_CRBA0];

    /* Calculate the ethernet checksum */
    checksum = cpu_to_le32(crc32(0, buf, rx_len));

    /* Put packet into RBA */
    DPRINTF("Receive packet at %08x\n", dp8393x_crba(s));
    address = dp8393x_crba(s);
    address_space_rw(&s->as, address,
        MEMTXATTRS_UNSPECIFIED, (uint8_t *)buf, rx_len, 1);
    address += rx_len;
    address_space_rw(&s->as, address,
        MEMTXATTRS_UNSPECIFIED, (uint8_t *)&checksum, 4, 1);
    rx_len += 4;
    s->regs[SONIC_CRBA1] = address >> 16;
    s->regs[SONIC_CRBA0] = address & 0xffff;
    available = dp8393x_rbwc(s);
    available -= rx_len / 2;
    s->regs[SONIC_RBWC1] = available >> 16;
    s->regs[SONIC_RBWC0] = available & 0xffff;

    /* Update status */
    if (dp8393x_rbwc(s) < s->regs[SONIC_EOBC]) {
        s->regs[SONIC_RCR] |= SONIC_RCR_LPKT;
    }
    s->regs[SONIC_RCR] |= packet_type;
    s->regs[SONIC_RCR] |= SONIC_RCR_PRX;
    if (s->loopback_packet) {
        s->regs[SONIC_RCR] |= SONIC_RCR_LBK;
        s->loopback_packet = 0;
    }

    /* Write status to memory */
    DPRINTF("Write status at %08x\n", dp8393x_crda(s));
    data[0 * width] = s->regs[SONIC_RCR]; /* status */
    data[1 * width] = rx_len; /* byte count */
    data[2 * width] = s->regs[SONIC_TRBA0]; /* pkt_ptr0 */
    data[3 * width] = s->regs[SONIC_TRBA1]; /* pkt_ptr1 */
    data[4 * width] = s->regs[SONIC_RSC]; /* seq_no */
    size = sizeof(uint16_t) * 5 * width;
    address_space_rw(&s->as, dp8393x_crda(s),
        MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 1);

    /* Move to next descriptor */
    size = sizeof(uint16_t) * width;
    address_space_rw(&s->as, dp8393x_crda(s) + sizeof(uint16_t) * 5 * width,
        MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
    s->regs[SONIC_LLFA] = data[0 * width];
    if (s->regs[SONIC_LLFA] & 0x1) {
        /* EOL detected */
        s->regs[SONIC_ISR] |= SONIC_ISR_RDE;
    } else {
        data[0 * width] = 0; /* in_use */
        address_space_rw(&s->as, dp8393x_crda(s) + sizeof(uint16_t) * 6 * width,
            MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, sizeof(uint16_t), 1);
        s->regs[SONIC_CRDA] = s->regs[SONIC_LLFA];
        s->regs[SONIC_ISR] |= SONIC_ISR_PKTRX;
        s->regs[SONIC_RSC] = (s->regs[SONIC_RSC] & 0xff00) | (((s->regs[SONIC_RSC] & 0x00ff) + 1) & 0x00ff);

        if (s->regs[SONIC_RCR] & SONIC_RCR_LPKT) {
            /* Read next RRA */
            dp8393x_do_read_rra(s);
        }
    }

    /* Done */
    dp8393x_update_irq(s);

    return size;
}

static void dp8393x_reset(DeviceState *dev)
{
    dp8393xState *s = DP8393X(dev);
    timer_del(s->watchdog);

    memset(s->regs, 0, sizeof(s->regs));
    s->regs[SONIC_CR] = SONIC_CR_RST | SONIC_CR_STP | SONIC_CR_RXDIS;
    s->regs[SONIC_DCR] &= ~(SONIC_DCR_EXBUS | SONIC_DCR_LBR);
    s->regs[SONIC_RCR] &= ~(SONIC_RCR_LB0 | SONIC_RCR_LB1 | SONIC_RCR_BRD | SONIC_RCR_RNT);
    s->regs[SONIC_TCR] |= SONIC_TCR_NCRS | SONIC_TCR_PTX;
    s->regs[SONIC_TCR] &= ~SONIC_TCR_BCM;
    s->regs[SONIC_IMR] = 0;
    s->regs[SONIC_ISR] = 0;
    s->regs[SONIC_DCR2] = 0;
    s->regs[SONIC_EOBC] = 0x02F8;
    s->regs[SONIC_RSC] = 0;
    s->regs[SONIC_CE] = 0;
    s->regs[SONIC_RSC] = 0;

    /* Network cable is connected */
    s->regs[SONIC_RCR] |= SONIC_RCR_CRS;

    dp8393x_update_irq(s);
}

static NetClientInfo net_dp83932_info = {
    .type = NET_CLIENT_DRIVER_NIC,
    .size = sizeof(NICState),
    .can_receive = dp8393x_can_receive,
    .receive = dp8393x_receive,
};

static void dp8393x_instance_init(Object *obj)
{
    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
    dp8393xState *s = DP8393X(obj);

    sysbus_init_mmio(sbd, &s->mmio);
    sysbus_init_mmio(sbd, &s->prom);
    sysbus_init_irq(sbd, &s->irq);
}

static void dp8393x_realize(DeviceState *dev, Error **errp)
{
    dp8393xState *s = DP8393X(dev);
    int i, checksum;
    uint8_t *prom;
    Error *local_err = NULL;

    address_space_init(&s->as, s->dma_mr, "dp8393x");
    memory_region_init_io(&s->mmio, OBJECT(dev), &dp8393x_ops, s,
                          "dp8393x-regs", 0x40 << s->it_shift);

    s->nic = qemu_new_nic(&net_dp83932_info, &s->conf,
                          object_get_typename(OBJECT(dev)), dev->id, s);
    qemu_format_nic_info_str(qemu_get_queue(s->nic), s->conf.macaddr.a);

    s->watchdog = timer_new_ns(QEMU_CLOCK_VIRTUAL, dp8393x_watchdog, s);
    s->regs[SONIC_SR] = 0x0004; /* only revision recognized by Linux */

    memory_region_init_ram(&s->prom, OBJECT(dev),
                           "dp8393x-prom", SONIC_PROM_SIZE, &local_err);
    if (local_err) {
        error_propagate(errp, local_err);
        return;
    }
    memory_region_set_readonly(&s->prom, true);
    prom = memory_region_get_ram_ptr(&s->prom);
    checksum = 0;
    for (i = 0; i < 6; i++) {
        prom[i] = s->conf.macaddr.a[i];
        checksum += prom[i];
        if (checksum > 0xff) {
            checksum = (checksum + 1) & 0xff;
        }
    }
    prom[7] = 0xff - checksum;
}

static const VMStateDescription vmstate_dp8393x = {
    .name = "dp8393x",
    .version_id = 0,
    .minimum_version_id = 0,
    .fields = (VMStateField []) {
        VMSTATE_BUFFER_UNSAFE(cam, dp8393xState, 0, 16 * 6),
        VMSTATE_UINT16_ARRAY(regs, dp8393xState, 0x40),
        VMSTATE_END_OF_LIST()
    }
};

static Property dp8393x_properties[] = {
    DEFINE_NIC_PROPERTIES(dp8393xState, conf),
    DEFINE_PROP_PTR("dma_mr", dp8393xState, dma_mr),
    DEFINE_PROP_UINT8("it_shift", dp8393xState, it_shift, 0),
    DEFINE_PROP_END_OF_LIST(),
};

static void dp8393x_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);

    set_bit(DEVICE_CATEGORY_NETWORK, dc->categories);
    dc->realize = dp8393x_realize;
    dc->reset = dp8393x_reset;
    dc->vmsd = &vmstate_dp8393x;
    dc->props = dp8393x_properties;
    /* Reason: dma_mr property can't be set */
    dc->user_creatable = false;
}

static const TypeInfo dp8393x_info = {
    .name          = TYPE_DP8393X,
    .parent        = TYPE_SYS_BUS_DEVICE,
    .instance_size = sizeof(dp8393xState),
    .instance_init = dp8393x_instance_init,
    .class_init    = dp8393x_class_init,
};

static void dp8393x_register_types(void)
{
    type_register_static(&dp8393x_info);
}

type_init(dp8393x_register_types)