summaryrefslogtreecommitdiff
path: root/drivers/net/pasemi_mac.c
blob: 4a451f8c6f4d98203d41cc43a9e9f4816808b205 (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
/*
 * Copyright (C) 2006-2007 PA Semi, Inc
 *
 * Driver for the PA Semi PWRficient onchip 1G/10G Ethernet MACs
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/dmaengine.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <asm/dma-mapping.h>
#include <linux/in.h>
#include <linux/skbuff.h>

#include <linux/ip.h>
#include <linux/tcp.h>
#include <net/checksum.h>

#include <asm/irq.h>

#include "pasemi_mac.h"

/* We have our own align, since ppc64 in general has it at 0 because
 * of design flaws in some of the server bridge chips. However, for
 * PWRficient doing the unaligned copies is more expensive than doing
 * unaligned DMA, so make sure the data is aligned instead.
 */
#define LOCAL_SKB_ALIGN	2

/* TODO list
 *
 * - Get rid of pci_{read,write}_config(), map registers with ioremap
 *   for performance
 * - PHY support
 * - Multicast support
 * - Large MTU support
 * - Other performance improvements
 */


/* Must be a power of two */
#define RX_RING_SIZE 4096
#define TX_RING_SIZE 4096

#define DEFAULT_MSG_ENABLE	  \
	(NETIF_MSG_DRV		| \
	 NETIF_MSG_PROBE	| \
	 NETIF_MSG_LINK		| \
	 NETIF_MSG_TIMER	| \
	 NETIF_MSG_IFDOWN	| \
	 NETIF_MSG_IFUP		| \
	 NETIF_MSG_RX_ERR	| \
	 NETIF_MSG_TX_ERR)

#define TX_RING(mac, num)	((mac)->tx->ring[(num) & (TX_RING_SIZE-1)])
#define TX_RING_INFO(mac, num)	((mac)->tx->ring_info[(num) & (TX_RING_SIZE-1)])
#define RX_RING(mac, num)	((mac)->rx->ring[(num) & (RX_RING_SIZE-1)])
#define RX_RING_INFO(mac, num)	((mac)->rx->ring_info[(num) & (RX_RING_SIZE-1)])
#define RX_BUFF(mac, num)	((mac)->rx->buffers[(num) & (RX_RING_SIZE-1)])

#define RING_USED(ring)		(((ring)->next_to_fill - (ring)->next_to_clean) \
				 & ((ring)->size - 1))
#define RING_AVAIL(ring)	((ring->size) - RING_USED(ring))

#define BUF_SIZE 1646 /* 1500 MTU + ETH_HLEN + VLAN_HLEN + 2 64B cachelines */

MODULE_LICENSE("GPL");
MODULE_AUTHOR ("Olof Johansson <olof@lixom.net>");
MODULE_DESCRIPTION("PA Semi PWRficient Ethernet driver");

static int debug = -1;	/* -1 == use DEFAULT_MSG_ENABLE as value */
module_param(debug, int, 0);
MODULE_PARM_DESC(debug, "PA Semi MAC bitmapped debugging message enable value");

static struct pasdma_status *dma_status;

static void write_iob_reg(struct pasemi_mac *mac, unsigned int reg,
			  unsigned int val)
{
	out_le32(mac->iob_regs+reg, val);
}

static unsigned int read_mac_reg(struct pasemi_mac *mac, unsigned int reg)
{
	return in_le32(mac->regs+reg);
}

static void write_mac_reg(struct pasemi_mac *mac, unsigned int reg,
			  unsigned int val)
{
	out_le32(mac->regs+reg, val);
}

static unsigned int read_dma_reg(struct pasemi_mac *mac, unsigned int reg)
{
	return in_le32(mac->dma_regs+reg);
}

static void write_dma_reg(struct pasemi_mac *mac, unsigned int reg,
			  unsigned int val)
{
	out_le32(mac->dma_regs+reg, val);
}

static int pasemi_get_mac_addr(struct pasemi_mac *mac)
{
	struct pci_dev *pdev = mac->pdev;
	struct device_node *dn = pci_device_to_OF_node(pdev);
	int len;
	const u8 *maddr;
	u8 addr[6];

	if (!dn) {
		dev_dbg(&pdev->dev,
			  "No device node for mac, not configuring\n");
		return -ENOENT;
	}

	maddr = of_get_property(dn, "local-mac-address", &len);

	if (maddr && len == 6) {
		memcpy(mac->mac_addr, maddr, 6);
		return 0;
	}

	/* Some old versions of firmware mistakenly uses mac-address
	 * (and as a string) instead of a byte array in local-mac-address.
	 */

	if (maddr == NULL)
		maddr = of_get_property(dn, "mac-address", NULL);

	if (maddr == NULL) {
		dev_warn(&pdev->dev,
			 "no mac address in device tree, not configuring\n");
		return -ENOENT;
	}


	if (sscanf(maddr, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx", &addr[0],
		   &addr[1], &addr[2], &addr[3], &addr[4], &addr[5]) != 6) {
		dev_warn(&pdev->dev,
			 "can't parse mac address, not configuring\n");
		return -EINVAL;
	}

	memcpy(mac->mac_addr, addr, 6);

	return 0;
}

static int pasemi_mac_unmap_tx_skb(struct pasemi_mac *mac,
				    struct sk_buff *skb,
				    dma_addr_t *dmas)
{
	int f;
	int nfrags = skb_shinfo(skb)->nr_frags;

	pci_unmap_single(mac->dma_pdev, dmas[0], skb_headlen(skb),
			 PCI_DMA_TODEVICE);

	for (f = 0; f < nfrags; f++) {
		skb_frag_t *frag = &skb_shinfo(skb)->frags[f];

		pci_unmap_page(mac->dma_pdev, dmas[f+1], frag->size,
			       PCI_DMA_TODEVICE);
	}
	dev_kfree_skb_irq(skb);

	/* Freed descriptor slot + main SKB ptr + nfrags additional ptrs,
	 * aligned up to a power of 2
	 */
	return (nfrags + 3) & ~1;
}

static int pasemi_mac_setup_rx_resources(struct net_device *dev)
{
	struct pasemi_mac_rxring *ring;
	struct pasemi_mac *mac = netdev_priv(dev);
	int chan_id = mac->dma_rxch;

	ring = kzalloc(sizeof(*ring), GFP_KERNEL);

	if (!ring)
		goto out_ring;

	spin_lock_init(&ring->lock);

	ring->size = RX_RING_SIZE;
	ring->ring_info = kzalloc(sizeof(struct pasemi_mac_buffer) *
				  RX_RING_SIZE, GFP_KERNEL);

	if (!ring->ring_info)
		goto out_ring_info;

	/* Allocate descriptors */
	ring->ring = dma_alloc_coherent(&mac->dma_pdev->dev,
					RX_RING_SIZE * sizeof(u64),
					&ring->dma, GFP_KERNEL);

	if (!ring->ring)
		goto out_ring_desc;

	memset(ring->ring, 0, RX_RING_SIZE * sizeof(u64));

	ring->buffers = dma_alloc_coherent(&mac->dma_pdev->dev,
					   RX_RING_SIZE * sizeof(u64),
					   &ring->buf_dma, GFP_KERNEL);
	if (!ring->buffers)
		goto out_buffers;

	memset(ring->buffers, 0, RX_RING_SIZE * sizeof(u64));

	write_dma_reg(mac, PAS_DMA_RXCHAN_BASEL(chan_id), PAS_DMA_RXCHAN_BASEL_BRBL(ring->dma));

	write_dma_reg(mac, PAS_DMA_RXCHAN_BASEU(chan_id),
			   PAS_DMA_RXCHAN_BASEU_BRBH(ring->dma >> 32) |
			   PAS_DMA_RXCHAN_BASEU_SIZ(RX_RING_SIZE >> 3));

	write_dma_reg(mac, PAS_DMA_RXCHAN_CFG(chan_id),
			   PAS_DMA_RXCHAN_CFG_HBU(2));

	write_dma_reg(mac, PAS_DMA_RXINT_BASEL(mac->dma_if),
			   PAS_DMA_RXINT_BASEL_BRBL(__pa(ring->buffers)));

	write_dma_reg(mac, PAS_DMA_RXINT_BASEU(mac->dma_if),
			   PAS_DMA_RXINT_BASEU_BRBH(__pa(ring->buffers) >> 32) |
			   PAS_DMA_RXINT_BASEU_SIZ(RX_RING_SIZE >> 3));

	write_dma_reg(mac, PAS_DMA_RXINT_CFG(mac->dma_if),
			   PAS_DMA_RXINT_CFG_DHL(3) |
			   PAS_DMA_RXINT_CFG_L2 |
			   PAS_DMA_RXINT_CFG_LW);

	ring->next_to_fill = 0;
	ring->next_to_clean = 0;

	snprintf(ring->irq_name, sizeof(ring->irq_name),
		 "%s rx", dev->name);
	mac->rx = ring;

	return 0;

out_buffers:
	dma_free_coherent(&mac->dma_pdev->dev,
			  RX_RING_SIZE * sizeof(u64),
			  mac->rx->ring, mac->rx->dma);
out_ring_desc:
	kfree(ring->ring_info);
out_ring_info:
	kfree(ring);
out_ring:
	return -ENOMEM;
}


static int pasemi_mac_setup_tx_resources(struct net_device *dev)
{
	struct pasemi_mac *mac = netdev_priv(dev);
	u32 val;
	int chan_id = mac->dma_txch;
	struct pasemi_mac_txring *ring;

	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
	if (!ring)
		goto out_ring;

	spin_lock_init(&ring->lock);

	ring->size = TX_RING_SIZE;
	ring->ring_info = kzalloc(sizeof(struct pasemi_mac_buffer) *
				  TX_RING_SIZE, GFP_KERNEL);
	if (!ring->ring_info)
		goto out_ring_info;

	/* Allocate descriptors */
	ring->ring = dma_alloc_coherent(&mac->dma_pdev->dev,
					TX_RING_SIZE * sizeof(u64),
					&ring->dma, GFP_KERNEL);
	if (!ring->ring)
		goto out_ring_desc;

	memset(ring->ring, 0, TX_RING_SIZE * sizeof(u64));

	write_dma_reg(mac, PAS_DMA_TXCHAN_BASEL(chan_id),
			   PAS_DMA_TXCHAN_BASEL_BRBL(ring->dma));
	val = PAS_DMA_TXCHAN_BASEU_BRBH(ring->dma >> 32);
	val |= PAS_DMA_TXCHAN_BASEU_SIZ(TX_RING_SIZE >> 3);

	write_dma_reg(mac, PAS_DMA_TXCHAN_BASEU(chan_id), val);

	write_dma_reg(mac, PAS_DMA_TXCHAN_CFG(chan_id),
			   PAS_DMA_TXCHAN_CFG_TY_IFACE |
			   PAS_DMA_TXCHAN_CFG_TATTR(mac->dma_if) |
			   PAS_DMA_TXCHAN_CFG_UP |
			   PAS_DMA_TXCHAN_CFG_WT(2));

	ring->next_to_fill = 0;
	ring->next_to_clean = 0;

	snprintf(ring->irq_name, sizeof(ring->irq_name),
		 "%s tx", dev->name);
	mac->tx = ring;

	return 0;

out_ring_desc:
	kfree(ring->ring_info);
out_ring_info:
	kfree(ring);
out_ring:
	return -ENOMEM;
}

static void pasemi_mac_free_tx_resources(struct net_device *dev)
{
	struct pasemi_mac *mac = netdev_priv(dev);
	unsigned int i, j;
	struct pasemi_mac_buffer *info;
	dma_addr_t dmas[MAX_SKB_FRAGS+1];
	int freed;
	int start, limit;

	start = mac->tx->next_to_clean;
	limit = mac->tx->next_to_fill;

	/* Compensate for when fill has wrapped and clean has not */
	if (start > limit)
		limit += TX_RING_SIZE;

	for (i = start; i < limit; i += freed) {
		info = &TX_RING_INFO(mac, i+1);
		if (info->dma && info->skb) {
			for (j = 0; j <= skb_shinfo(info->skb)->nr_frags; j++)
				dmas[j] = TX_RING_INFO(mac, i+1+j).dma;
			freed = pasemi_mac_unmap_tx_skb(mac, info->skb, dmas);
		} else
			freed = 2;
	}

	for (i = 0; i < TX_RING_SIZE; i++)
		TX_RING(mac, i) = 0;

	dma_free_coherent(&mac->dma_pdev->dev,
			  TX_RING_SIZE * sizeof(u64),
			  mac->tx->ring, mac->tx->dma);

	kfree(mac->tx->ring_info);
	kfree(mac->tx);
	mac->tx = NULL;
}

static void pasemi_mac_free_rx_resources(struct net_device *dev)
{
	struct pasemi_mac *mac = netdev_priv(dev);
	unsigned int i;
	struct pasemi_mac_buffer *info;

	for (i = 0; i < RX_RING_SIZE; i++) {
		info = &RX_RING_INFO(mac, i);
		if (info->skb && info->dma) {
			pci_unmap_single(mac->dma_pdev,
					 info->dma,
					 info->skb->len,
					 PCI_DMA_FROMDEVICE);
			dev_kfree_skb_any(info->skb);
		}
		info->dma = 0;
		info->skb = NULL;
	}

	for (i = 0; i < RX_RING_SIZE; i++)
		RX_RING(mac, i) = 0;

	dma_free_coherent(&mac->dma_pdev->dev,
			  RX_RING_SIZE * sizeof(u64),
			  mac->rx->ring, mac->rx->dma);

	dma_free_coherent(&mac->dma_pdev->dev, RX_RING_SIZE * sizeof(u64),
			  mac->rx->buffers, mac->rx->buf_dma);

	kfree(mac->rx->ring_info);
	kfree(mac->rx);
	mac->rx = NULL;
}

static void pasemi_mac_replenish_rx_ring(struct net_device *dev, int limit)
{
	struct pasemi_mac *mac = netdev_priv(dev);
	int start = mac->rx->next_to_fill;
	unsigned int fill, count;

	if (limit <= 0)
		return;

	fill = start;
	for (count = 0; count < limit; count++) {
		struct pasemi_mac_buffer *info = &RX_RING_INFO(mac, fill);
		u64 *buff = &RX_BUFF(mac, fill);
		struct sk_buff *skb;
		dma_addr_t dma;

		/* Entry in use? */
		WARN_ON(*buff);

		/* skb might still be in there for recycle on short receives */
		if (info->skb)
			skb = info->skb;
		else {
			skb = dev_alloc_skb(BUF_SIZE);
			skb_reserve(skb, LOCAL_SKB_ALIGN);
		}

		if (unlikely(!skb))
			break;

		dma = pci_map_single(mac->dma_pdev, skb->data,
				     BUF_SIZE - LOCAL_SKB_ALIGN,
				     PCI_DMA_FROMDEVICE);

		if (unlikely(dma_mapping_error(dma))) {
			dev_kfree_skb_irq(info->skb);
			break;
		}

		info->skb = skb;
		info->dma = dma;
		*buff = XCT_RXB_LEN(BUF_SIZE) | XCT_RXB_ADDR(dma);
		fill++;
	}

	wmb();

	write_dma_reg(mac, PAS_DMA_RXCHAN_INCR(mac->dma_rxch), count);
	write_dma_reg(mac, PAS_DMA_RXINT_INCR(mac->dma_if), count);

	mac->rx->next_to_fill += count;
}

static void pasemi_mac_restart_rx_intr(struct pasemi_mac *mac)
{
	unsigned int reg, pcnt;
	/* Re-enable packet count interrupts: finally
	 * ack the packet count interrupt we got in rx_intr.
	 */

	pcnt = *mac->rx_status & PAS_STATUS_PCNT_M;

	reg = PAS_IOB_DMA_RXCH_RESET_PCNT(pcnt) | PAS_IOB_DMA_RXCH_RESET_PINTC;

	write_iob_reg(mac, PAS_IOB_DMA_RXCH_RESET(mac->dma_rxch), reg);
}

static void pasemi_mac_restart_tx_intr(struct pasemi_mac *mac)
{
	unsigned int reg, pcnt;

	/* Re-enable packet count interrupts */
	pcnt = *mac->tx_status & PAS_STATUS_PCNT_M;

	reg = PAS_IOB_DMA_TXCH_RESET_PCNT(pcnt) | PAS_IOB_DMA_TXCH_RESET_PINTC;

	write_iob_reg(mac, PAS_IOB_DMA_TXCH_RESET(mac->dma_txch), reg);
}


static inline void pasemi_mac_rx_error(struct pasemi_mac *mac, u64 macrx)
{
	unsigned int rcmdsta, ccmdsta;

	if (!netif_msg_rx_err(mac))
		return;

	rcmdsta = read_dma_reg(mac, PAS_DMA_RXINT_RCMDSTA(mac->dma_if));
	ccmdsta = read_dma_reg(mac, PAS_DMA_RXCHAN_CCMDSTA(mac->dma_rxch));

	printk(KERN_ERR "pasemi_mac: rx error. macrx %016lx, rx status %lx\n",
		macrx, *mac->rx_status);

	printk(KERN_ERR "pasemi_mac: rcmdsta %08x ccmdsta %08x\n",
		rcmdsta, ccmdsta);
}

static inline void pasemi_mac_tx_error(struct pasemi_mac *mac, u64 mactx)
{
	unsigned int cmdsta;

	if (!netif_msg_tx_err(mac))
		return;

	cmdsta = read_dma_reg(mac, PAS_DMA_TXCHAN_TCMDSTA(mac->dma_txch));

	printk(KERN_ERR "pasemi_mac: tx error. mactx 0x%016lx, "\
		"tx status 0x%016lx\n", mactx, *mac->tx_status);

	printk(KERN_ERR "pasemi_mac: tcmdsta 0x%08x\n", cmdsta);
}

static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
{
	unsigned int n;
	int count;
	struct pasemi_mac_buffer *info;
	struct sk_buff *skb;
	unsigned int i, len;
	u64 macrx;
	dma_addr_t dma;

	spin_lock(&mac->rx->lock);

	n = mac->rx->next_to_clean;

	for (count = limit; count; count--) {
		macrx = RX_RING(mac, n);

		if ((macrx & XCT_MACRX_E) ||
		    (*mac->rx_status & PAS_STATUS_ERROR))
			pasemi_mac_rx_error(mac, macrx);

		if (!(macrx & XCT_MACRX_O))
			break;

		info = NULL;

		/* We have to scan for our skb since there's no way
		 * to back-map them from the descriptor, and if we
		 * have several receive channels then they might not
		 * show up in the same order as they were put on the
		 * interface ring.
		 */

		dma = (RX_RING(mac, n+1) & XCT_PTR_ADDR_M);
		for (i = mac->rx->next_to_fill;
		     i < (mac->rx->next_to_fill + RX_RING_SIZE);
		     i++) {
			info = &RX_RING_INFO(mac, i);
			if (info->dma == dma)
				break;
		}

		skb = info->skb;

		prefetch(skb);
		prefetch(&skb->data_len);

		len = (macrx & XCT_MACRX_LLEN_M) >> XCT_MACRX_LLEN_S;

		if (len < 256) {
			struct sk_buff *new_skb;

			new_skb = netdev_alloc_skb(mac->netdev,
						   len + LOCAL_SKB_ALIGN);
			if (new_skb) {
				skb_reserve(new_skb, LOCAL_SKB_ALIGN);
				memcpy(new_skb->data, skb->data, len);
				/* save the skb in buffer_info as good */
				skb = new_skb;
			}
			/* else just continue with the old one */
		} else
			info->skb = NULL;

		pci_unmap_single(mac->dma_pdev, dma, len, PCI_DMA_FROMDEVICE);

		info->dma = 0;

		skb_put(skb, len);

		if (likely((macrx & XCT_MACRX_HTY_M) == XCT_MACRX_HTY_IPV4_OK)) {
			skb->ip_summed = CHECKSUM_UNNECESSARY;
			skb->csum = (macrx & XCT_MACRX_CSUM_M) >>
					   XCT_MACRX_CSUM_S;
		} else
			skb->ip_summed = CHECKSUM_NONE;

		mac->netdev->stats.rx_bytes += len;
		mac->netdev->stats.rx_packets++;

		skb->protocol = eth_type_trans(skb, mac->netdev);
		netif_receive_skb(skb);

		RX_RING(mac, n) = 0;
		RX_RING(mac, n+1) = 0;

		/* Need to zero it out since hardware doesn't, since the
		 * replenish loop uses it to tell when it's done.
		 */
		RX_BUFF(mac, i) = 0;

		n += 2;
	}

	if (n > RX_RING_SIZE) {
		/* Errata 5971 workaround: L2 target of headers */
		write_iob_reg(mac, PAS_IOB_COM_PKTHDRCNT, 0);
		n &= (RX_RING_SIZE-1);
	}
	mac->rx->next_to_clean = n;
	pasemi_mac_replenish_rx_ring(mac->netdev, limit-count);

	spin_unlock(&mac->rx->lock);

	return count;
}

/* Can't make this too large or we blow the kernel stack limits */
#define TX_CLEAN_BATCHSIZE (128/MAX_SKB_FRAGS)

static int pasemi_mac_clean_tx(struct pasemi_mac *mac)
{
	int i, j;
	unsigned int start, descr_count, buf_count, batch_limit;
	unsigned int ring_limit;
	unsigned int total_count;
	unsigned long flags;
	struct sk_buff *skbs[TX_CLEAN_BATCHSIZE];
	dma_addr_t dmas[TX_CLEAN_BATCHSIZE][MAX_SKB_FRAGS+1];

	total_count = 0;
	batch_limit = TX_CLEAN_BATCHSIZE;
restart:
	spin_lock_irqsave(&mac->tx->lock, flags);

	start = mac->tx->next_to_clean;
	ring_limit = mac->tx->next_to_fill;

	/* Compensate for when fill has wrapped but clean has not */
	if (start > ring_limit)
		ring_limit += TX_RING_SIZE;

	buf_count = 0;
	descr_count = 0;

	for (i = start;
	     descr_count < batch_limit && i < ring_limit;
	     i += buf_count) {
		u64 mactx = TX_RING(mac, i);
		struct sk_buff *skb;

		if ((mactx  & XCT_MACTX_E) ||
		    (*mac->tx_status & PAS_STATUS_ERROR))
			pasemi_mac_tx_error(mac, mactx);

		if (unlikely(mactx & XCT_MACTX_O))
			/* Not yet transmitted */
			break;

		skb = TX_RING_INFO(mac, i+1).skb;
		skbs[descr_count] = skb;

		buf_count = 2 + skb_shinfo(skb)->nr_frags;
		for (j = 0; j <= skb_shinfo(skb)->nr_frags; j++)
			dmas[descr_count][j] = TX_RING_INFO(mac, i+1+j).dma;

		TX_RING(mac, i) = 0;
		TX_RING(mac, i+1) = 0;

		/* Since we always fill with an even number of entries, make
		 * sure we skip any unused one at the end as well.
		 */
		if (buf_count & 1)
			buf_count++;
		descr_count++;
	}
	mac->tx->next_to_clean = i & (TX_RING_SIZE-1);

	spin_unlock_irqrestore(&mac->tx->lock, flags);
	netif_wake_queue(mac->netdev);

	for (i = 0; i < descr_count; i++)
		pasemi_mac_unmap_tx_skb(mac, skbs[i], dmas[i]);

	total_count += descr_count;

	/* If the batch was full, try to clean more */
	if (descr_count == batch_limit)
		goto restart;

	return total_count;
}


static irqreturn_t pasemi_mac_rx_intr(int irq, void *data)
{
	struct net_device *dev = data;
	struct pasemi_mac *mac = netdev_priv(dev);
	unsigned int reg;

	if (!(*mac->rx_status & PAS_STATUS_CAUSE_M))
		return IRQ_NONE;

	/* Don't reset packet count so it won't fire again but clear
	 * all others.
	 */

	reg = 0;
	if (*mac->rx_status & PAS_STATUS_SOFT)
		reg |= PAS_IOB_DMA_RXCH_RESET_SINTC;
	if (*mac->rx_status & PAS_STATUS_ERROR)
		reg |= PAS_IOB_DMA_RXCH_RESET_DINTC;
	if (*mac->rx_status & PAS_STATUS_TIMER)
		reg |= PAS_IOB_DMA_RXCH_RESET_TINTC;

	netif_rx_schedule(dev, &mac->napi);

	write_iob_reg(mac, PAS_IOB_DMA_RXCH_RESET(mac->dma_rxch), reg);

	return IRQ_HANDLED;
}

static irqreturn_t pasemi_mac_tx_intr(int irq, void *data)
{
	struct net_device *dev = data;
	struct pasemi_mac *mac = netdev_priv(dev);
	unsigned int reg, pcnt;

	if (!(*mac->tx_status & PAS_STATUS_CAUSE_M))
		return IRQ_NONE;

	pasemi_mac_clean_tx(mac);

	pcnt = *mac->tx_status & PAS_STATUS_PCNT_M;

	reg = PAS_IOB_DMA_TXCH_RESET_PCNT(pcnt) | PAS_IOB_DMA_TXCH_RESET_PINTC;

	if (*mac->tx_status & PAS_STATUS_SOFT)
		reg |= PAS_IOB_DMA_TXCH_RESET_SINTC;
	if (*mac->tx_status & PAS_STATUS_ERROR)
		reg |= PAS_IOB_DMA_TXCH_RESET_DINTC;

	write_iob_reg(mac, PAS_IOB_DMA_TXCH_RESET(mac->dma_txch), reg);

	return IRQ_HANDLED;
}

static void pasemi_adjust_link(struct net_device *dev)
{
	struct pasemi_mac *mac = netdev_priv(dev);
	int msg;
	unsigned int flags;
	unsigned int new_flags;

	if (!mac->phydev->link) {
		/* If no link, MAC speed settings don't matter. Just report
		 * link down and return.
		 */
		if (mac->link && netif_msg_link(mac))
			printk(KERN_INFO "%s: Link is down.\n", dev->name);

		netif_carrier_off(dev);
		mac->link = 0;

		return;
	} else
		netif_carrier_on(dev);

	flags = read_mac_reg(mac, PAS_MAC_CFG_PCFG);
	new_flags = flags & ~(PAS_MAC_CFG_PCFG_HD | PAS_MAC_CFG_PCFG_SPD_M |
			      PAS_MAC_CFG_PCFG_TSR_M);

	if (!mac->phydev->duplex)
		new_flags |= PAS_MAC_CFG_PCFG_HD;

	switch (mac->phydev->speed) {
	case 1000:
		new_flags |= PAS_MAC_CFG_PCFG_SPD_1G |
			     PAS_MAC_CFG_PCFG_TSR_1G;
		break;
	case 100:
		new_flags |= PAS_MAC_CFG_PCFG_SPD_100M |
			     PAS_MAC_CFG_PCFG_TSR_100M;
		break;
	case 10:
		new_flags |= PAS_MAC_CFG_PCFG_SPD_10M |
			     PAS_MAC_CFG_PCFG_TSR_10M;
		break;
	default:
		printk("Unsupported speed %d\n", mac->phydev->speed);
	}

	/* Print on link or speed/duplex change */
	msg = mac->link != mac->phydev->link || flags != new_flags;

	mac->duplex = mac->phydev->duplex;
	mac->speed = mac->phydev->speed;
	mac->link = mac->phydev->link;

	if (new_flags != flags)
		write_mac_reg(mac, PAS_MAC_CFG_PCFG, new_flags);

	if (msg && netif_msg_link(mac))
		printk(KERN_INFO "%s: Link is up at %d Mbps, %s duplex.\n",
		       dev->name, mac->speed, mac->duplex ? "full" : "half");
}

static int pasemi_mac_phy_init(struct net_device *dev)
{
	struct pasemi_mac *mac = netdev_priv(dev);
	struct device_node *dn, *phy_dn;
	struct phy_device *phydev;
	unsigned int phy_id;
	const phandle *ph;
	const unsigned int *prop;
	struct resource r;
	int ret;

	dn = pci_device_to_OF_node(mac->pdev);
	ph = of_get_property(dn, "phy-handle", NULL);
	if (!ph)
		return -ENODEV;
	phy_dn = of_find_node_by_phandle(*ph);

	prop = of_get_property(phy_dn, "reg", NULL);
	ret = of_address_to_resource(phy_dn->parent, 0, &r);
	if (ret)
		goto err;

	phy_id = *prop;
	snprintf(mac->phy_id, BUS_ID_SIZE, PHY_ID_FMT, (int)r.start, phy_id);

	of_node_put(phy_dn);

	mac->link = 0;
	mac->speed = 0;
	mac->duplex = -1;

	phydev = phy_connect(dev, mac->phy_id, &pasemi_adjust_link, 0, PHY_INTERFACE_MODE_SGMII);

	if (IS_ERR(phydev)) {
		printk(KERN_ERR "%s: Could not attach to phy\n", dev->name);
		return PTR_ERR(phydev);
	}

	mac->phydev = phydev;

	return 0;

err:
	of_node_put(phy_dn);
	return -ENODEV;
}


static int pasemi_mac_open(struct net_device *dev)
{
	struct pasemi_mac *mac = netdev_priv(dev);
	int base_irq;
	unsigned int flags;
	int ret;

	/* enable rx section */
	write_dma_reg(mac, PAS_DMA_COM_RXCMD, PAS_DMA_COM_RXCMD_EN);

	/* enable tx section */
	write_dma_reg(mac, PAS_DMA_COM_TXCMD, PAS_DMA_COM_TXCMD_EN);

	flags = PAS_MAC_CFG_TXP_FCE | PAS_MAC_CFG_TXP_FPC(3) |
		PAS_MAC_CFG_TXP_SL(3) | PAS_MAC_CFG_TXP_COB(0xf) |
		PAS_MAC_CFG_TXP_TIFT(8) | PAS_MAC_CFG_TXP_TIFG(12);

	write_mac_reg(mac, PAS_MAC_CFG_TXP, flags);

	write_iob_reg(mac, PAS_IOB_DMA_RXCH_CFG(mac->dma_rxch),
			   PAS_IOB_DMA_RXCH_CFG_CNTTH(0));

	write_iob_reg(mac, PAS_IOB_DMA_TXCH_CFG(mac->dma_txch),
			   PAS_IOB_DMA_TXCH_CFG_CNTTH(128));

	/* Clear out any residual packet count state from firmware */
	pasemi_mac_restart_rx_intr(mac);
	pasemi_mac_restart_tx_intr(mac);

	/* 0xffffff is max value, about 16ms */
	write_iob_reg(mac, PAS_IOB_DMA_COM_TIMEOUTCFG,
			   PAS_IOB_DMA_COM_TIMEOUTCFG_TCNT(0xffffff));

	ret = pasemi_mac_setup_rx_resources(dev);
	if (ret)
		goto out_rx_resources;

	ret = pasemi_mac_setup_tx_resources(dev);
	if (ret)
		goto out_tx_resources;

	write_mac_reg(mac, PAS_MAC_IPC_CHNL,
			   PAS_MAC_IPC_CHNL_DCHNO(mac->dma_rxch) |
			   PAS_MAC_IPC_CHNL_BCH(mac->dma_rxch));

	/* enable rx if */
	write_dma_reg(mac, PAS_DMA_RXINT_RCMDSTA(mac->dma_if),
			   PAS_DMA_RXINT_RCMDSTA_EN);

	/* enable rx channel */
	write_dma_reg(mac, PAS_DMA_RXCHAN_CCMDSTA(mac->dma_rxch),
			   PAS_DMA_RXCHAN_CCMDSTA_EN |
			   PAS_DMA_RXCHAN_CCMDSTA_DU);

	/* enable tx channel */
	write_dma_reg(mac, PAS_DMA_TXCHAN_TCMDSTA(mac->dma_txch),
			   PAS_DMA_TXCHAN_TCMDSTA_EN);

	pasemi_mac_replenish_rx_ring(dev, RX_RING_SIZE);

	flags = PAS_MAC_CFG_PCFG_S1 | PAS_MAC_CFG_PCFG_PE |
		PAS_MAC_CFG_PCFG_PR | PAS_MAC_CFG_PCFG_CE;

	if (mac->type == MAC_TYPE_GMAC)
		flags |= PAS_MAC_CFG_PCFG_TSR_1G | PAS_MAC_CFG_PCFG_SPD_1G;
	else
		flags |= PAS_MAC_CFG_PCFG_TSR_10G | PAS_MAC_CFG_PCFG_SPD_10G;

	/* Enable interface in MAC */
	write_mac_reg(mac, PAS_MAC_CFG_PCFG, flags);

	ret = pasemi_mac_phy_init(dev);
	/* Some configs don't have PHYs (XAUI etc), so don't complain about
	 * failed init due to -ENODEV.
	 */
	if (ret && ret != -ENODEV)
		dev_warn(&mac->pdev->dev, "phy init failed: %d\n", ret);

	netif_start_queue(dev);
	napi_enable(&mac->napi);

	/* Interrupts are a bit different for our DMA controller: While
	 * it's got one a regular PCI device header, the interrupt there
	 * is really the base of the range it's using. Each tx and rx
	 * channel has it's own interrupt source.
	 */

	base_irq = virq_to_hw(mac->dma_pdev->irq);

	mac->tx_irq = irq_create_mapping(NULL, base_irq + mac->dma_txch);
	mac->rx_irq = irq_create_mapping(NULL, base_irq + 20 + mac->dma_txch);

	ret = request_irq(mac->tx_irq, &pasemi_mac_tx_intr, IRQF_DISABLED,
			  mac->tx->irq_name, dev);
	if (ret) {
		dev_err(&mac->pdev->dev, "request_irq of irq %d failed: %d\n",
			base_irq + mac->dma_txch, ret);
		goto out_tx_int;
	}

	ret = request_irq(mac->rx_irq, &pasemi_mac_rx_intr, IRQF_DISABLED,
			  mac->rx->irq_name, dev);
	if (ret) {
		dev_err(&mac->pdev->dev, "request_irq of irq %d failed: %d\n",
			base_irq + 20 + mac->dma_rxch, ret);
		goto out_rx_int;
	}

	if (mac->phydev)
		phy_start(mac->phydev);

	return 0;

out_rx_int:
	free_irq(mac->tx_irq, dev);
out_tx_int:
	napi_disable(&mac->napi);
	netif_stop_queue(dev);
	pasemi_mac_free_tx_resources(dev);
out_tx_resources:
	pasemi_mac_free_rx_resources(dev);
out_rx_resources:

	return ret;
}

#define MAX_RETRIES 5000

static int pasemi_mac_close(struct net_device *dev)
{
	struct pasemi_mac *mac = netdev_priv(dev);
	unsigned int stat;
	int retries;

	if (mac->phydev) {
		phy_stop(mac->phydev);
		phy_disconnect(mac->phydev);
	}

	netif_stop_queue(dev);
	napi_disable(&mac->napi);

	/* Clean out any pending buffers */
	pasemi_mac_clean_tx(mac);
	pasemi_mac_clean_rx(mac, RX_RING_SIZE);

	/* Disable interface */
	write_dma_reg(mac, PAS_DMA_TXCHAN_TCMDSTA(mac->dma_txch), PAS_DMA_TXCHAN_TCMDSTA_ST);
	write_dma_reg(mac, PAS_DMA_RXINT_RCMDSTA(mac->dma_if), PAS_DMA_RXINT_RCMDSTA_ST);
	write_dma_reg(mac, PAS_DMA_RXCHAN_CCMDSTA(mac->dma_rxch), PAS_DMA_RXCHAN_CCMDSTA_ST);

	for (retries = 0; retries < MAX_RETRIES; retries++) {
		stat = read_dma_reg(mac, PAS_DMA_TXCHAN_TCMDSTA(mac->dma_txch));
		if (!(stat & PAS_DMA_TXCHAN_TCMDSTA_ACT))
			break;
		cond_resched();
	}

	if (stat & PAS_DMA_TXCHAN_TCMDSTA_ACT)
		dev_err(&mac->dma_pdev->dev, "Failed to stop tx channel\n");

	for (retries = 0; retries < MAX_RETRIES; retries++) {
		stat = read_dma_reg(mac, PAS_DMA_RXCHAN_CCMDSTA(mac->dma_rxch));
		if (!(stat & PAS_DMA_RXCHAN_CCMDSTA_ACT))
			break;
		cond_resched();
	}

	if (stat & PAS_DMA_RXCHAN_CCMDSTA_ACT)
		dev_err(&mac->dma_pdev->dev, "Failed to stop rx channel\n");

	for (retries = 0; retries < MAX_RETRIES; retries++) {
		stat = read_dma_reg(mac, PAS_DMA_RXINT_RCMDSTA(mac->dma_if));
		if (!(stat & PAS_DMA_RXINT_RCMDSTA_ACT))
			break;
		cond_resched();
	}

	if (stat & PAS_DMA_RXINT_RCMDSTA_ACT)
		dev_err(&mac->dma_pdev->dev, "Failed to stop rx interface\n");

	/* Then, disable the channel. This must be done separately from
	 * stopping, since you can't disable when active.
	 */

	write_dma_reg(mac, PAS_DMA_TXCHAN_TCMDSTA(mac->dma_txch), 0);
	write_dma_reg(mac, PAS_DMA_RXCHAN_CCMDSTA(mac->dma_rxch), 0);
	write_dma_reg(mac, PAS_DMA_RXINT_RCMDSTA(mac->dma_if), 0);

	free_irq(mac->tx_irq, dev);
	free_irq(mac->rx_irq, dev);

	/* Free resources */
	pasemi_mac_free_rx_resources(dev);
	pasemi_mac_free_tx_resources(dev);

	return 0;
}

static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
{
	struct pasemi_mac *mac = netdev_priv(dev);
	struct pasemi_mac_txring *txring;
	u64 dflags, mactx;
	dma_addr_t map[MAX_SKB_FRAGS+1];
	unsigned int map_size[MAX_SKB_FRAGS+1];
	unsigned long flags;
	int i, nfrags;

	dflags = XCT_MACTX_O | XCT_MACTX_ST | XCT_MACTX_SS | XCT_MACTX_CRC_PAD;

	if (skb->ip_summed == CHECKSUM_PARTIAL) {
		const unsigned char *nh = skb_network_header(skb);

		switch (ip_hdr(skb)->protocol) {
		case IPPROTO_TCP:
			dflags |= XCT_MACTX_CSUM_TCP;
			dflags |= XCT_MACTX_IPH(skb_network_header_len(skb) >> 2);
			dflags |= XCT_MACTX_IPO(nh - skb->data);
			break;
		case IPPROTO_UDP:
			dflags |= XCT_MACTX_CSUM_UDP;
			dflags |= XCT_MACTX_IPH(skb_network_header_len(skb) >> 2);
			dflags |= XCT_MACTX_IPO(nh - skb->data);
			break;
		}
	}

	nfrags = skb_shinfo(skb)->nr_frags;

	map[0] = pci_map_single(mac->dma_pdev, skb->data, skb_headlen(skb),
				PCI_DMA_TODEVICE);
	map_size[0] = skb_headlen(skb);
	if (dma_mapping_error(map[0]))
		goto out_err_nolock;

	for (i = 0; i < nfrags; i++) {
		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

		map[i+1] = pci_map_page(mac->dma_pdev, frag->page,
					frag->page_offset, frag->size,
					PCI_DMA_TODEVICE);
		map_size[i+1] = frag->size;
		if (dma_mapping_error(map[i+1])) {
			nfrags = i;
			goto out_err_nolock;
		}
	}

	mactx = dflags | XCT_MACTX_LLEN(skb->len);

	txring = mac->tx;

	spin_lock_irqsave(&txring->lock, flags);

	/* Avoid stepping on the same cache line that the DMA controller
	 * is currently about to send, so leave at least 8 words available.
	 * Total free space needed is mactx + fragments + 8
	 */
	if (RING_AVAIL(txring) < nfrags + 10) {
		/* no room -- stop the queue and wait for tx intr */
		netif_stop_queue(dev);
		goto out_err;
	}

	TX_RING(mac, txring->next_to_fill) = mactx;
	txring->next_to_fill++;
	TX_RING_INFO(mac, txring->next_to_fill).skb = skb;
	for (i = 0; i <= nfrags; i++) {
		TX_RING(mac, txring->next_to_fill+i) =
		XCT_PTR_LEN(map_size[i]) | XCT_PTR_ADDR(map[i]);
		TX_RING_INFO(mac, txring->next_to_fill+i).dma = map[i];
	}

	/* We have to add an even number of 8-byte entries to the ring
	 * even if the last one is unused. That means always an odd number
	 * of pointers + one mactx descriptor.
	 */
	if (nfrags & 1)
		nfrags++;

	txring->next_to_fill = (txring->next_to_fill + nfrags + 1) &
				(TX_RING_SIZE-1);

	dev->stats.tx_packets++;
	dev->stats.tx_bytes += skb->len;

	spin_unlock_irqrestore(&txring->lock, flags);

	write_dma_reg(mac, PAS_DMA_TXCHAN_INCR(mac->dma_txch), (nfrags+2) >> 1);

	return NETDEV_TX_OK;

out_err:
	spin_unlock_irqrestore(&txring->lock, flags);
out_err_nolock:
	while (nfrags--)
		pci_unmap_single(mac->dma_pdev, map[nfrags], map_size[nfrags],
				 PCI_DMA_TODEVICE);

	return NETDEV_TX_BUSY;
}

static void pasemi_mac_set_rx_mode(struct net_device *dev)
{
	struct pasemi_mac *mac = netdev_priv(dev);
	unsigned int flags;

	flags = read_mac_reg(mac, PAS_MAC_CFG_PCFG);

	/* Set promiscuous */
	if (dev->flags & IFF_PROMISC)
		flags |= PAS_MAC_CFG_PCFG_PR;
	else
		flags &= ~PAS_MAC_CFG_PCFG_PR;

	write_mac_reg(mac, PAS_MAC_CFG_PCFG, flags);
}


static int pasemi_mac_poll(struct napi_struct *napi, int budget)
{
	struct pasemi_mac *mac = container_of(napi, struct pasemi_mac, napi);
	struct net_device *dev = mac->netdev;
	int pkts;

	pasemi_mac_clean_tx(mac);
	pkts = pasemi_mac_clean_rx(mac, budget);
	if (pkts < budget) {
		/* all done, no more packets present */
		netif_rx_complete(dev, napi);

		pasemi_mac_restart_rx_intr(mac);
	}
	return pkts;
}

static void __iomem * __devinit map_onedev(struct pci_dev *p, int index)
{
	struct device_node *dn;
	void __iomem *ret;

	dn = pci_device_to_OF_node(p);
	if (!dn)
		goto fallback;

	ret = of_iomap(dn, index);
	if (!ret)
		goto fallback;

	return ret;
fallback:
	/* This is hardcoded and ugly, but we have some firmware versions
	 * that don't provide the register space in the device tree. Luckily
	 * they are at well-known locations so we can just do the math here.
	 */
	return ioremap(0xe0000000 + (p->devfn << 12), 0x2000);
}

static int __devinit pasemi_mac_map_regs(struct pasemi_mac *mac)
{
	struct resource res;
	struct device_node *dn;
	int err;

	mac->dma_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa007, NULL);
	if (!mac->dma_pdev) {
		dev_err(&mac->pdev->dev, "Can't find DMA Controller\n");
		return -ENODEV;
	}

	mac->iob_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa001, NULL);
	if (!mac->iob_pdev) {
		dev_err(&mac->pdev->dev, "Can't find I/O Bridge\n");
		return -ENODEV;
	}

	mac->regs = map_onedev(mac->pdev, 0);
	mac->dma_regs = map_onedev(mac->dma_pdev, 0);
	mac->iob_regs = map_onedev(mac->iob_pdev, 0);

	if (!mac->regs || !mac->dma_regs || !mac->iob_regs) {
		dev_err(&mac->pdev->dev, "Can't map registers\n");
		return -ENODEV;
	}

	/* The dma status structure is located in the I/O bridge, and
	 * is cache coherent.
	 */
	if (!dma_status) {
		dn = pci_device_to_OF_node(mac->iob_pdev);
		if (dn)
			err = of_address_to_resource(dn, 1, &res);
		if (!dn || err) {
			/* Fallback for old firmware */
			res.start = 0xfd800000;
			res.end = res.start + 0x1000;
		}
		dma_status = __ioremap(res.start, res.end-res.start, 0);
	}

	return 0;
}

static int __devinit
pasemi_mac_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
	static int index = 0;
	struct net_device *dev;
	struct pasemi_mac *mac;
	int err;
	DECLARE_MAC_BUF(mac_buf);

	err = pci_enable_device(pdev);
	if (err)
		return err;

	dev = alloc_etherdev(sizeof(struct pasemi_mac));
	if (dev == NULL) {
		dev_err(&pdev->dev,
			"pasemi_mac: Could not allocate ethernet device.\n");
		err = -ENOMEM;
		goto out_disable_device;
	}

	pci_set_drvdata(pdev, dev);
	SET_NETDEV_DEV(dev, &pdev->dev);

	mac = netdev_priv(dev);

	mac->pdev = pdev;
	mac->netdev = dev;

	netif_napi_add(dev, &mac->napi, pasemi_mac_poll, 64);

	dev->features = NETIF_F_HW_CSUM | NETIF_F_LLTX | NETIF_F_SG;

	/* These should come out of the device tree eventually */
	mac->dma_txch = index;
	mac->dma_rxch = index;

	/* We probe GMAC before XAUI, but the DMA interfaces are
	 * in XAUI, GMAC order.
	 */
	if (index < 4)
		mac->dma_if = index + 2;
	else
		mac->dma_if = index - 4;
	index++;

	switch (pdev->device) {
	case 0xa005:
		mac->type = MAC_TYPE_GMAC;
		break;
	case 0xa006:
		mac->type = MAC_TYPE_XAUI;
		break;
	default:
		err = -ENODEV;
		goto out;
	}

	/* get mac addr from device tree */
	if (pasemi_get_mac_addr(mac) || !is_valid_ether_addr(mac->mac_addr)) {
		err = -ENODEV;
		goto out;
	}
	memcpy(dev->dev_addr, mac->mac_addr, sizeof(mac->mac_addr));

	dev->open = pasemi_mac_open;
	dev->stop = pasemi_mac_close;
	dev->hard_start_xmit = pasemi_mac_start_tx;
	dev->set_multicast_list = pasemi_mac_set_rx_mode;

	err = pasemi_mac_map_regs(mac);
	if (err)
		goto out;

	mac->rx_status = &dma_status->rx_sta[mac->dma_rxch];
	mac->tx_status = &dma_status->tx_sta[mac->dma_txch];

	mac->msg_enable = netif_msg_init(debug, DEFAULT_MSG_ENABLE);

	/* Enable most messages by default */
	mac->msg_enable = (NETIF_MSG_IFUP << 1 ) - 1;

	err = register_netdev(dev);

	if (err) {
		dev_err(&mac->pdev->dev, "register_netdev failed with error %d\n",
			err);
		goto out;
	} else if netif_msg_probe(mac)
		printk(KERN_INFO "%s: PA Semi %s: intf %d, txch %d, rxch %d, "
		       "hw addr %s\n",
		       dev->name, mac->type == MAC_TYPE_GMAC ? "GMAC" : "XAUI",
		       mac->dma_if, mac->dma_txch, mac->dma_rxch,
		       print_mac(mac_buf, dev->dev_addr));

	return err;

out:
	if (mac->iob_pdev)
		pci_dev_put(mac->iob_pdev);
	if (mac->dma_pdev)
		pci_dev_put(mac->dma_pdev);
	if (mac->dma_regs)
		iounmap(mac->dma_regs);
	if (mac->iob_regs)
		iounmap(mac->iob_regs);
	if (mac->regs)
		iounmap(mac->regs);

	free_netdev(dev);
out_disable_device:
	pci_disable_device(pdev);
	return err;

}

static void __devexit pasemi_mac_remove(struct pci_dev *pdev)
{
	struct net_device *netdev = pci_get_drvdata(pdev);
	struct pasemi_mac *mac;

	if (!netdev)
		return;

	mac = netdev_priv(netdev);

	unregister_netdev(netdev);

	pci_disable_device(pdev);
	pci_dev_put(mac->dma_pdev);
	pci_dev_put(mac->iob_pdev);

	iounmap(mac->regs);
	iounmap(mac->dma_regs);
	iounmap(mac->iob_regs);

	pci_set_drvdata(pdev, NULL);
	free_netdev(netdev);
}

static struct pci_device_id pasemi_mac_pci_tbl[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_PASEMI, 0xa005) },
	{ PCI_DEVICE(PCI_VENDOR_ID_PASEMI, 0xa006) },
	{ },
};

MODULE_DEVICE_TABLE(pci, pasemi_mac_pci_tbl);

static struct pci_driver pasemi_mac_driver = {
	.name		= "pasemi_mac",
	.id_table	= pasemi_mac_pci_tbl,
	.probe		= pasemi_mac_probe,
	.remove		= __devexit_p(pasemi_mac_remove),
};

static void __exit pasemi_mac_cleanup_module(void)
{
	pci_unregister_driver(&pasemi_mac_driver);
	__iounmap(dma_status);
	dma_status = NULL;
}

int pasemi_mac_init_module(void)
{
	return pci_register_driver(&pasemi_mac_driver);
}

module_init(pasemi_mac_init_module);
module_exit(pasemi_mac_cleanup_module);