summaryrefslogtreecommitdiffstats
path: root/drivers/net/ethernet/faraday/ftmac100.c
blob: bb336a0959c9147624ff6c23d63ee71138f7663d (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
/*
 * Faraday FTMAC100 10/100 Ethernet
 *
 * (C) Copyright 2009-2011 Faraday Technology
 * Po-Yu Chuang <ratbert@faraday-tech.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 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, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

#include <linux/dma-mapping.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/mii.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/platform_device.h>

#include "ftmac100.h"

#define DRV_NAME	"ftmac100"
#define DRV_VERSION	"0.2"

#define RX_QUEUE_ENTRIES	128	/* must be power of 2 */
#define TX_QUEUE_ENTRIES	16	/* must be power of 2 */

#define MAX_PKT_SIZE		1518
#define RX_BUF_SIZE		2044	/* must be smaller than 0x7ff */

#if MAX_PKT_SIZE > 0x7ff
#error invalid MAX_PKT_SIZE
#endif

#if RX_BUF_SIZE > 0x7ff || RX_BUF_SIZE > PAGE_SIZE
#error invalid RX_BUF_SIZE
#endif

/******************************************************************************
 * private data
 *****************************************************************************/
struct ftmac100_descs {
	struct ftmac100_rxdes rxdes[RX_QUEUE_ENTRIES];
	struct ftmac100_txdes txdes[TX_QUEUE_ENTRIES];
};

struct ftmac100 {
	struct resource *res;
	void __iomem *base;
	int irq;

	struct ftmac100_descs *descs;
	dma_addr_t descs_dma_addr;

	unsigned int rx_pointer;
	unsigned int tx_clean_pointer;
	unsigned int tx_pointer;
	unsigned int tx_pending;

	spinlock_t tx_lock;

	struct net_device *netdev;
	struct device *dev;
	struct napi_struct napi;

	struct mii_if_info mii;
};

static int ftmac100_alloc_rx_page(struct ftmac100 *priv,
				  struct ftmac100_rxdes *rxdes, gfp_t gfp);

/******************************************************************************
 * internal functions (hardware register access)
 *****************************************************************************/
#define INT_MASK_ALL_ENABLED	(FTMAC100_INT_RPKT_FINISH	| \
				 FTMAC100_INT_NORXBUF		| \
				 FTMAC100_INT_XPKT_OK		| \
				 FTMAC100_INT_XPKT_LOST		| \
				 FTMAC100_INT_RPKT_LOST		| \
				 FTMAC100_INT_AHB_ERR		| \
				 FTMAC100_INT_PHYSTS_CHG)

#define INT_MASK_ALL_DISABLED	0

static void ftmac100_enable_all_int(struct ftmac100 *priv)
{
	iowrite32(INT_MASK_ALL_ENABLED, priv->base + FTMAC100_OFFSET_IMR);
}

static void ftmac100_disable_all_int(struct ftmac100 *priv)
{
	iowrite32(INT_MASK_ALL_DISABLED, priv->base + FTMAC100_OFFSET_IMR);
}

static void ftmac100_set_rx_ring_base(struct ftmac100 *priv, dma_addr_t addr)
{
	iowrite32(addr, priv->base + FTMAC100_OFFSET_RXR_BADR);
}

static void ftmac100_set_tx_ring_base(struct ftmac100 *priv, dma_addr_t addr)
{
	iowrite32(addr, priv->base + FTMAC100_OFFSET_TXR_BADR);
}

static void ftmac100_txdma_start_polling(struct ftmac100 *priv)
{
	iowrite32(1, priv->base + FTMAC100_OFFSET_TXPD);
}

static int ftmac100_reset(struct ftmac100 *priv)
{
	struct net_device *netdev = priv->netdev;
	int i;

	/* NOTE: reset clears all registers */
	iowrite32(FTMAC100_MACCR_SW_RST, priv->base + FTMAC100_OFFSET_MACCR);

	for (i = 0; i < 5; i++) {
		unsigned int maccr;

		maccr = ioread32(priv->base + FTMAC100_OFFSET_MACCR);
		if (!(maccr & FTMAC100_MACCR_SW_RST)) {
			/*
			 * FTMAC100_MACCR_SW_RST cleared does not indicate
			 * that hardware reset completed (what the f*ck).
			 * We still need to wait for a while.
			 */
			udelay(500);
			return 0;
		}

		udelay(1000);
	}

	netdev_err(netdev, "software reset failed\n");
	return -EIO;
}

static void ftmac100_set_mac(struct ftmac100 *priv, const unsigned char *mac)
{
	unsigned int maddr = mac[0] << 8 | mac[1];
	unsigned int laddr = mac[2] << 24 | mac[3] << 16 | mac[4] << 8 | mac[5];

	iowrite32(maddr, priv->base + FTMAC100_OFFSET_MAC_MADR);
	iowrite32(laddr, priv->base + FTMAC100_OFFSET_MAC_LADR);
}

#define MACCR_ENABLE_ALL	(FTMAC100_MACCR_XMT_EN	| \
				 FTMAC100_MACCR_RCV_EN	| \
				 FTMAC100_MACCR_XDMA_EN	| \
				 FTMAC100_MACCR_RDMA_EN	| \
				 FTMAC100_MACCR_CRC_APD	| \
				 FTMAC100_MACCR_FULLDUP	| \
				 FTMAC100_MACCR_RX_RUNT	| \
				 FTMAC100_MACCR_RX_BROADPKT)

static int ftmac100_start_hw(struct ftmac100 *priv)
{
	struct net_device *netdev = priv->netdev;

	if (ftmac100_reset(priv))
		return -EIO;

	/* setup ring buffer base registers */
	ftmac100_set_rx_ring_base(priv,
				  priv->descs_dma_addr +
				  offsetof(struct ftmac100_descs, rxdes));
	ftmac100_set_tx_ring_base(priv,
				  priv->descs_dma_addr +
				  offsetof(struct ftmac100_descs, txdes));

	iowrite32(FTMAC100_APTC_RXPOLL_CNT(1), priv->base + FTMAC100_OFFSET_APTC);

	ftmac100_set_mac(priv, netdev->dev_addr);

	iowrite32(MACCR_ENABLE_ALL, priv->base + FTMAC100_OFFSET_MACCR);
	return 0;
}

static void ftmac100_stop_hw(struct ftmac100 *priv)
{
	iowrite32(0, priv->base + FTMAC100_OFFSET_MACCR);
}

/******************************************************************************
 * internal functions (receive descriptor)
 *****************************************************************************/
static bool ftmac100_rxdes_first_segment(struct ftmac100_rxdes *rxdes)
{
	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_FRS);
}

static bool ftmac100_rxdes_last_segment(struct ftmac100_rxdes *rxdes)
{
	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_LRS);
}

static bool ftmac100_rxdes_owned_by_dma(struct ftmac100_rxdes *rxdes)
{
	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_RXDMA_OWN);
}

static void ftmac100_rxdes_set_dma_own(struct ftmac100_rxdes *rxdes)
{
	/* clear status bits */
	rxdes->rxdes0 = cpu_to_le32(FTMAC100_RXDES0_RXDMA_OWN);
}

static bool ftmac100_rxdes_rx_error(struct ftmac100_rxdes *rxdes)
{
	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_RX_ERR);
}

static bool ftmac100_rxdes_crc_error(struct ftmac100_rxdes *rxdes)
{
	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_CRC_ERR);
}

static bool ftmac100_rxdes_frame_too_long(struct ftmac100_rxdes *rxdes)
{
	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_FTL);
}

static bool ftmac100_rxdes_runt(struct ftmac100_rxdes *rxdes)
{
	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_RUNT);
}

static bool ftmac100_rxdes_odd_nibble(struct ftmac100_rxdes *rxdes)
{
	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_RX_ODD_NB);
}

static unsigned int ftmac100_rxdes_frame_length(struct ftmac100_rxdes *rxdes)
{
	return le32_to_cpu(rxdes->rxdes0) & FTMAC100_RXDES0_RFL;
}

static bool ftmac100_rxdes_multicast(struct ftmac100_rxdes *rxdes)
{
	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_MULTICAST);
}

static void ftmac100_rxdes_set_buffer_size(struct ftmac100_rxdes *rxdes,
					   unsigned int size)
{
	rxdes->rxdes1 &= cpu_to_le32(FTMAC100_RXDES1_EDORR);
	rxdes->rxdes1 |= cpu_to_le32(FTMAC100_RXDES1_RXBUF_SIZE(size));
}

static void ftmac100_rxdes_set_end_of_ring(struct ftmac100_rxdes *rxdes)
{
	rxdes->rxdes1 |= cpu_to_le32(FTMAC100_RXDES1_EDORR);
}

static void ftmac100_rxdes_set_dma_addr(struct ftmac100_rxdes *rxdes,
					dma_addr_t addr)
{
	rxdes->rxdes2 = cpu_to_le32(addr);
}

static dma_addr_t ftmac100_rxdes_get_dma_addr(struct ftmac100_rxdes *rxdes)
{
	return le32_to_cpu(rxdes->rxdes2);
}

/*
 * rxdes3 is not used by hardware. We use it to keep track of page.
 * Since hardware does not touch it, we can skip cpu_to_le32()/le32_to_cpu().
 */
static void ftmac100_rxdes_set_page(struct ftmac100_rxdes *rxdes, struct page *page)
{
	rxdes->rxdes3 = (unsigned int)page;
}

static struct page *ftmac100_rxdes_get_page(struct ftmac100_rxdes *rxdes)
{
	return (struct page *)rxdes->rxdes3;
}

/******************************************************************************
 * internal functions (receive)
 *****************************************************************************/
static int ftmac100_next_rx_pointer(int pointer)
{
	return (pointer + 1) & (RX_QUEUE_ENTRIES - 1);
}

static void ftmac100_rx_pointer_advance(struct ftmac100 *priv)
{
	priv->rx_pointer = ftmac100_next_rx_pointer(priv->rx_pointer);
}

static struct ftmac100_rxdes *ftmac100_current_rxdes(struct ftmac100 *priv)
{
	return &priv->descs->rxdes[priv->rx_pointer];
}

static struct ftmac100_rxdes *
ftmac100_rx_locate_first_segment(struct ftmac100 *priv)
{
	struct ftmac100_rxdes *rxdes = ftmac100_current_rxdes(priv);

	while (!ftmac100_rxdes_owned_by_dma(rxdes)) {
		if (ftmac100_rxdes_first_segment(rxdes))
			return rxdes;

		ftmac100_rxdes_set_dma_own(rxdes);
		ftmac100_rx_pointer_advance(priv);
		rxdes = ftmac100_current_rxdes(priv);
	}

	return NULL;
}

static bool ftmac100_rx_packet_error(struct ftmac100 *priv,
				     struct ftmac100_rxdes *rxdes)
{
	struct net_device *netdev = priv->netdev;
	bool error = false;

	if (unlikely(ftmac100_rxdes_rx_error(rxdes))) {
		if (net_ratelimit())
			netdev_info(netdev, "rx err\n");

		netdev->stats.rx_errors++;
		error = true;
	}

	if (unlikely(ftmac100_rxdes_crc_error(rxdes))) {
		if (net_ratelimit())
			netdev_info(netdev, "rx crc err\n");

		netdev->stats.rx_crc_errors++;
		error = true;
	}

	if (unlikely(ftmac100_rxdes_frame_too_long(rxdes))) {
		if (net_ratelimit())
			netdev_info(netdev, "rx frame too long\n");

		netdev->stats.rx_length_errors++;
		error = true;
	} else if (unlikely(ftmac100_rxdes_runt(rxdes))) {
		if (net_ratelimit())
			netdev_info(netdev, "rx runt\n");

		netdev->stats.rx_length_errors++;
		error = true;
	} else if (unlikely(ftmac100_rxdes_odd_nibble(rxdes))) {
		if (net_ratelimit())
			netdev_info(netdev, "rx odd nibble\n");

		netdev->stats.rx_length_errors++;
		error = true;
	}

	return error;
}

static void ftmac100_rx_drop_packet(struct ftmac100 *priv)
{
	struct net_device *netdev = priv->netdev;
	struct ftmac100_rxdes *rxdes = ftmac100_current_rxdes(priv);
	bool done = false;

	if (net_ratelimit())
		netdev_dbg(netdev, "drop packet %p\n", rxdes);

	do {
		if (ftmac100_rxdes_last_segment(rxdes))
			done = true;

		ftmac100_rxdes_set_dma_own(rxdes);
		ftmac100_rx_pointer_advance(priv);
		rxdes = ftmac100_current_rxdes(priv);
	} while (!done && !ftmac100_rxdes_owned_by_dma(rxdes));

	netdev->stats.rx_dropped++;
}

static bool ftmac100_rx_packet(struct ftmac100 *priv, int *processed)
{
	struct net_device *netdev = priv->netdev;
	struct ftmac100_rxdes *rxdes;
	struct sk_buff *skb;
	struct page *page;
	dma_addr_t map;
	int length;

	rxdes = ftmac100_rx_locate_first_segment(priv);
	if (!rxdes)
		return false;

	if (unlikely(ftmac100_rx_packet_error(priv, rxdes))) {
		ftmac100_rx_drop_packet(priv);
		return true;
	}

	/*
	 * It is impossible to get multi-segment packets
	 * because we always provide big enough receive buffers.
	 */
	if (unlikely(!ftmac100_rxdes_last_segment(rxdes)))
		BUG();

	/* start processing */
	skb = netdev_alloc_skb_ip_align(netdev, 128);
	if (unlikely(!skb)) {
		if (net_ratelimit())
			netdev_err(netdev, "rx skb alloc failed\n");

		ftmac100_rx_drop_packet(priv);
		return true;
	}

	if (unlikely(ftmac100_rxdes_multicast(rxdes)))
		netdev->stats.multicast++;

	map = ftmac100_rxdes_get_dma_addr(rxdes);
	dma_unmap_page(priv->dev, map, RX_BUF_SIZE, DMA_FROM_DEVICE);

	length = ftmac100_rxdes_frame_length(rxdes);
	page = ftmac100_rxdes_get_page(rxdes);
	skb_fill_page_desc(skb, 0, page, 0, length);
	skb->len += length;
	skb->data_len += length;

	/* page might be freed in __pskb_pull_tail() */
	if (length > 64)
		skb->truesize += PAGE_SIZE;
	__pskb_pull_tail(skb, min(length, 64));

	ftmac100_alloc_rx_page(priv, rxdes, GFP_ATOMIC);

	ftmac100_rx_pointer_advance(priv);

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

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

	/* push packet to protocol stack */
	netif_receive_skb(skb);

	(*processed)++;
	return true;
}

/******************************************************************************
 * internal functions (transmit descriptor)
 *****************************************************************************/
static void ftmac100_txdes_reset(struct ftmac100_txdes *txdes)
{
	/* clear all except end of ring bit */
	txdes->txdes0 = 0;
	txdes->txdes1 &= cpu_to_le32(FTMAC100_TXDES1_EDOTR);
	txdes->txdes2 = 0;
	txdes->txdes3 = 0;
}

static bool ftmac100_txdes_owned_by_dma(struct ftmac100_txdes *txdes)
{
	return txdes->txdes0 & cpu_to_le32(FTMAC100_TXDES0_TXDMA_OWN);
}

static void ftmac100_txdes_set_dma_own(struct ftmac100_txdes *txdes)
{
	/*
	 * Make sure dma own bit will not be set before any other
	 * descriptor fields.
	 */
	wmb();
	txdes->txdes0 |= cpu_to_le32(FTMAC100_TXDES0_TXDMA_OWN);
}

static bool ftmac100_txdes_excessive_collision(struct ftmac100_txdes *txdes)
{
	return txdes->txdes0 & cpu_to_le32(FTMAC100_TXDES0_TXPKT_EXSCOL);
}

static bool ftmac100_txdes_late_collision(struct ftmac100_txdes *txdes)
{
	return txdes->txdes0 & cpu_to_le32(FTMAC100_TXDES0_TXPKT_LATECOL);
}

static void ftmac100_txdes_set_end_of_ring(struct ftmac100_txdes *txdes)
{
	txdes->txdes1 |= cpu_to_le32(FTMAC100_TXDES1_EDOTR);
}

static void ftmac100_txdes_set_first_segment(struct ftmac100_txdes *txdes)
{
	txdes->txdes1 |= cpu_to_le32(FTMAC100_TXDES1_FTS);
}

static void ftmac100_txdes_set_last_segment(struct ftmac100_txdes *txdes)
{
	txdes->txdes1 |= cpu_to_le32(FTMAC100_TXDES1_LTS);
}

static void ftmac100_txdes_set_txint(struct ftmac100_txdes *txdes)
{
	txdes->txdes1 |= cpu_to_le32(FTMAC100_TXDES1_TXIC);
}

static void ftmac100_txdes_set_buffer_size(struct ftmac100_txdes *txdes,
					   unsigned int len)
{
	txdes->txdes1 |= cpu_to_le32(FTMAC100_TXDES1_TXBUF_SIZE(len));
}

static void ftmac100_txdes_set_dma_addr(struct ftmac100_txdes *txdes,
					dma_addr_t addr)
{
	txdes->txdes2 = cpu_to_le32(addr);
}

static dma_addr_t ftmac100_txdes_get_dma_addr(struct ftmac100_txdes *txdes)
{
	return le32_to_cpu(txdes->txdes2);
}

/*
 * txdes3 is not used by hardware. We use it to keep track of socket buffer.
 * Since hardware does not touch it, we can skip cpu_to_le32()/le32_to_cpu().
 */
static void ftmac100_txdes_set_skb(struct ftmac100_txdes *txdes, struct sk_buff *skb)
{
	txdes->txdes3 = (unsigned int)skb;
}

static struct sk_buff *ftmac100_txdes_get_skb(struct ftmac100_txdes *txdes)
{
	return (struct sk_buff *)txdes->txdes3;
}

/******************************************************************************
 * internal functions (transmit)
 *****************************************************************************/
static int ftmac100_next_tx_pointer(int pointer)
{
	return (pointer + 1) & (TX_QUEUE_ENTRIES - 1);
}

static void ftmac100_tx_pointer_advance(struct ftmac100 *priv)
{
	priv->tx_pointer = ftmac100_next_tx_pointer(priv->tx_pointer);
}

static void ftmac100_tx_clean_pointer_advance(struct ftmac100 *priv)
{
	priv->tx_clean_pointer = ftmac100_next_tx_pointer(priv->tx_clean_pointer);
}

static struct ftmac100_txdes *ftmac100_current_txdes(struct ftmac100 *priv)
{
	return &priv->descs->txdes[priv->tx_pointer];
}

static struct ftmac100_txdes *ftmac100_current_clean_txdes(struct ftmac100 *priv)
{
	return &priv->descs->txdes[priv->tx_clean_pointer];
}

static bool ftmac100_tx_complete_packet(struct ftmac100 *priv)
{
	struct net_device *netdev = priv->netdev;
	struct ftmac100_txdes *txdes;
	struct sk_buff *skb;
	dma_addr_t map;

	if (priv->tx_pending == 0)
		return false;

	txdes = ftmac100_current_clean_txdes(priv);

	if (ftmac100_txdes_owned_by_dma(txdes))
		return false;

	skb = ftmac100_txdes_get_skb(txdes);
	map = ftmac100_txdes_get_dma_addr(txdes);

	if (unlikely(ftmac100_txdes_excessive_collision(txdes) ||
		     ftmac100_txdes_late_collision(txdes))) {
		/*
		 * packet transmitted to ethernet lost due to late collision
		 * or excessive collision
		 */
		netdev->stats.tx_aborted_errors++;
	} else {
		netdev->stats.tx_packets++;
		netdev->stats.tx_bytes += skb->len;
	}

	dma_unmap_single(priv->dev, map, skb_headlen(skb), DMA_TO_DEVICE);
	dev_kfree_skb(skb);

	ftmac100_txdes_reset(txdes);

	ftmac100_tx_clean_pointer_advance(priv);

	spin_lock(&priv->tx_lock);
	priv->tx_pending--;
	spin_unlock(&priv->tx_lock);
	netif_wake_queue(netdev);

	return true;
}

static void ftmac100_tx_complete(struct ftmac100 *priv)
{
	while (ftmac100_tx_complete_packet(priv))
		;
}

static int ftmac100_xmit(struct ftmac100 *priv, struct sk_buff *skb,
			 dma_addr_t map)
{
	struct net_device *netdev = priv->netdev;
	struct ftmac100_txdes *txdes;
	unsigned int len = (skb->len < ETH_ZLEN) ? ETH_ZLEN : skb->len;

	txdes = ftmac100_current_txdes(priv);
	ftmac100_tx_pointer_advance(priv);

	/* setup TX descriptor */
	ftmac100_txdes_set_skb(txdes, skb);
	ftmac100_txdes_set_dma_addr(txdes, map);

	ftmac100_txdes_set_first_segment(txdes);
	ftmac100_txdes_set_last_segment(txdes);
	ftmac100_txdes_set_txint(txdes);
	ftmac100_txdes_set_buffer_size(txdes, len);

	spin_lock(&priv->tx_lock);
	priv->tx_pending++;
	if (priv->tx_pending == TX_QUEUE_ENTRIES)
		netif_stop_queue(netdev);

	/* start transmit */
	ftmac100_txdes_set_dma_own(txdes);
	spin_unlock(&priv->tx_lock);

	ftmac100_txdma_start_polling(priv);
	return NETDEV_TX_OK;
}

/******************************************************************************
 * internal functions (buffer)
 *****************************************************************************/
static int ftmac100_alloc_rx_page(struct ftmac100 *priv,
				  struct ftmac100_rxdes *rxdes, gfp_t gfp)
{
	struct net_device *netdev = priv->netdev;
	struct page *page;
	dma_addr_t map;

	page = alloc_page(gfp);
	if (!page) {
		if (net_ratelimit())
			netdev_err(netdev, "failed to allocate rx page\n");
		return -ENOMEM;
	}

	map = dma_map_page(priv->dev, page, 0, RX_BUF_SIZE, DMA_FROM_DEVICE);
	if (unlikely(dma_mapping_error(priv->dev, map))) {
		if (net_ratelimit())
			netdev_err(netdev, "failed to map rx page\n");
		__free_page(page);
		return -ENOMEM;
	}

	ftmac100_rxdes_set_page(rxdes, page);
	ftmac100_rxdes_set_dma_addr(rxdes, map);
	ftmac100_rxdes_set_buffer_size(rxdes, RX_BUF_SIZE);
	ftmac100_rxdes_set_dma_own(rxdes);
	return 0;
}

static void ftmac100_free_buffers(struct ftmac100 *priv)
{
	int i;

	for (i = 0; i < RX_QUEUE_ENTRIES; i++) {
		struct ftmac100_rxdes *rxdes = &priv->descs->rxdes[i];
		struct page *page = ftmac100_rxdes_get_page(rxdes);
		dma_addr_t map = ftmac100_rxdes_get_dma_addr(rxdes);

		if (!page)
			continue;

		dma_unmap_page(priv->dev, map, RX_BUF_SIZE, DMA_FROM_DEVICE);
		__free_page(page);
	}

	for (i = 0; i < TX_QUEUE_ENTRIES; i++) {
		struct ftmac100_txdes *txdes = &priv->descs->txdes[i];
		struct sk_buff *skb = ftmac100_txdes_get_skb(txdes);
		dma_addr_t map = ftmac100_txdes_get_dma_addr(txdes);

		if (!skb)
			continue;

		dma_unmap_single(priv->dev, map, skb_headlen(skb), DMA_TO_DEVICE);
		dev_kfree_skb(skb);
	}

	dma_free_coherent(priv->dev, sizeof(struct ftmac100_descs),
			  priv->descs, priv->descs_dma_addr);
}

static int ftmac100_alloc_buffers(struct ftmac100 *priv)
{
	int i;

	priv->descs = dma_alloc_coherent(priv->dev, sizeof(struct ftmac100_descs),
					 &priv->descs_dma_addr, GFP_KERNEL);
	if (!priv->descs)
		return -ENOMEM;

	memset(priv->descs, 0, sizeof(struct ftmac100_descs));

	/* initialize RX ring */
	ftmac100_rxdes_set_end_of_ring(&priv->descs->rxdes[RX_QUEUE_ENTRIES - 1]);

	for (i = 0; i < RX_QUEUE_ENTRIES; i++) {
		struct ftmac100_rxdes *rxdes = &priv->descs->rxdes[i];

		if (ftmac100_alloc_rx_page(priv, rxdes, GFP_KERNEL))
			goto err;
	}

	/* initialize TX ring */
	ftmac100_txdes_set_end_of_ring(&priv->descs->txdes[TX_QUEUE_ENTRIES - 1]);
	return 0;

err:
	ftmac100_free_buffers(priv);
	return -ENOMEM;
}

/******************************************************************************
 * struct mii_if_info functions
 *****************************************************************************/
static int ftmac100_mdio_read(struct net_device *netdev, int phy_id, int reg)
{
	struct ftmac100 *priv = netdev_priv(netdev);
	unsigned int phycr;
	int i;

	phycr = FTMAC100_PHYCR_PHYAD(phy_id) |
		FTMAC100_PHYCR_REGAD(reg) |
		FTMAC100_PHYCR_MIIRD;

	iowrite32(phycr, priv->base + FTMAC100_OFFSET_PHYCR);

	for (i = 0; i < 10; i++) {
		phycr = ioread32(priv->base + FTMAC100_OFFSET_PHYCR);

		if ((phycr & FTMAC100_PHYCR_MIIRD) == 0)
			return phycr & FTMAC100_PHYCR_MIIRDATA;

		udelay(100);
	}

	netdev_err(netdev, "mdio read timed out\n");
	return 0;
}

static void ftmac100_mdio_write(struct net_device *netdev, int phy_id, int reg,
				int data)
{
	struct ftmac100 *priv = netdev_priv(netdev);
	unsigned int phycr;
	int i;

	phycr = FTMAC100_PHYCR_PHYAD(phy_id) |
		FTMAC100_PHYCR_REGAD(reg) |
		FTMAC100_PHYCR_MIIWR;

	data = FTMAC100_PHYWDATA_MIIWDATA(data);

	iowrite32(data, priv->base + FTMAC100_OFFSET_PHYWDATA);
	iowrite32(phycr, priv->base + FTMAC100_OFFSET_PHYCR);

	for (i = 0; i < 10; i++) {
		phycr = ioread32(priv->base + FTMAC100_OFFSET_PHYCR);

		if ((phycr & FTMAC100_PHYCR_MIIWR) == 0)
			return;

		udelay(100);
	}

	netdev_err(netdev, "mdio write timed out\n");
}

/******************************************************************************
 * struct ethtool_ops functions
 *****************************************************************************/
static void ftmac100_get_drvinfo(struct net_device *netdev,
				 struct ethtool_drvinfo *info)
{
	strcpy(info->driver, DRV_NAME);
	strcpy(info->version, DRV_VERSION);
	strcpy(info->bus_info, dev_name(&netdev->dev));
}

static int ftmac100_get_settings(struct net_device *netdev, struct ethtool_cmd *cmd)
{
	struct ftmac100 *priv = netdev_priv(netdev);
	return mii_ethtool_gset(&priv->mii, cmd);
}

static int ftmac100_set_settings(struct net_device *netdev, struct ethtool_cmd *cmd)
{
	struct ftmac100 *priv = netdev_priv(netdev);
	return mii_ethtool_sset(&priv->mii, cmd);
}

static int ftmac100_nway_reset(struct net_device *netdev)
{
	struct ftmac100 *priv = netdev_priv(netdev);
	return mii_nway_restart(&priv->mii);
}

static u32 ftmac100_get_link(struct net_device *netdev)
{
	struct ftmac100 *priv = netdev_priv(netdev);
	return mii_link_ok(&priv->mii);
}

static const struct ethtool_ops ftmac100_ethtool_ops = {
	.set_settings		= ftmac100_set_settings,
	.get_settings		= ftmac100_get_settings,
	.get_drvinfo		= ftmac100_get_drvinfo,
	.nway_reset		= ftmac100_nway_reset,
	.get_link		= ftmac100_get_link,
};

/******************************************************************************
 * interrupt handler
 *****************************************************************************/
static irqreturn_t ftmac100_interrupt(int irq, void *dev_id)
{
	struct net_device *netdev = dev_id;
	struct ftmac100 *priv = netdev_priv(netdev);

	if (likely(netif_running(netdev))) {
		/* Disable interrupts for polling */
		ftmac100_disable_all_int(priv);
		napi_schedule(&priv->napi);
	}

	return IRQ_HANDLED;
}

/******************************************************************************
 * struct napi_struct functions
 *****************************************************************************/
static int ftmac100_poll(struct napi_struct *napi, int budget)
{
	struct ftmac100 *priv = container_of(napi, struct ftmac100, napi);
	struct net_device *netdev = priv->netdev;
	unsigned int status;
	bool completed = true;
	int rx = 0;

	status = ioread32(priv->base + FTMAC100_OFFSET_ISR);

	if (status & (FTMAC100_INT_RPKT_FINISH | FTMAC100_INT_NORXBUF)) {
		/*
		 * FTMAC100_INT_RPKT_FINISH:
		 *	RX DMA has received packets into RX buffer successfully
		 *
		 * FTMAC100_INT_NORXBUF:
		 *	RX buffer unavailable
		 */
		bool retry;

		do {
			retry = ftmac100_rx_packet(priv, &rx);
		} while (retry && rx < budget);

		if (retry && rx == budget)
			completed = false;
	}

	if (status & (FTMAC100_INT_XPKT_OK | FTMAC100_INT_XPKT_LOST)) {
		/*
		 * FTMAC100_INT_XPKT_OK:
		 *	packet transmitted to ethernet successfully
		 *
		 * FTMAC100_INT_XPKT_LOST:
		 *	packet transmitted to ethernet lost due to late
		 *	collision or excessive collision
		 */
		ftmac100_tx_complete(priv);
	}

	if (status & (FTMAC100_INT_NORXBUF | FTMAC100_INT_RPKT_LOST |
		      FTMAC100_INT_AHB_ERR | FTMAC100_INT_PHYSTS_CHG)) {
		if (net_ratelimit())
			netdev_info(netdev, "[ISR] = 0x%x: %s%s%s%s\n", status,
				    status & FTMAC100_INT_NORXBUF ? "NORXBUF " : "",
				    status & FTMAC100_INT_RPKT_LOST ? "RPKT_LOST " : "",
				    status & FTMAC100_INT_AHB_ERR ? "AHB_ERR " : "",
				    status & FTMAC100_INT_PHYSTS_CHG ? "PHYSTS_CHG" : "");

		if (status & FTMAC100_INT_NORXBUF) {
			/* RX buffer unavailable */
			netdev->stats.rx_over_errors++;
		}

		if (status & FTMAC100_INT_RPKT_LOST) {
			/* received packet lost due to RX FIFO full */
			netdev->stats.rx_fifo_errors++;
		}

		if (status & FTMAC100_INT_PHYSTS_CHG) {
			/* PHY link status change */
			mii_check_link(&priv->mii);
		}
	}

	if (completed) {
		/* stop polling */
		napi_complete(napi);
		ftmac100_enable_all_int(priv);
	}

	return rx;
}

/******************************************************************************
 * struct net_device_ops functions
 *****************************************************************************/
static int ftmac100_open(struct net_device *netdev)
{
	struct ftmac100 *priv = netdev_priv(netdev);
	int err;

	err = ftmac100_alloc_buffers(priv);
	if (err) {
		netdev_err(netdev, "failed to allocate buffers\n");
		goto err_alloc;
	}

	err = request_irq(priv->irq, ftmac100_interrupt, 0, netdev->name, netdev);
	if (err) {
		netdev_err(netdev, "failed to request irq %d\n", priv->irq);
		goto err_irq;
	}

	priv->rx_pointer = 0;
	priv->tx_clean_pointer = 0;
	priv->tx_pointer = 0;
	priv->tx_pending = 0;

	err = ftmac100_start_hw(priv);
	if (err)
		goto err_hw;

	napi_enable(&priv->napi);
	netif_start_queue(netdev);

	ftmac100_enable_all_int(priv);

	return 0;

err_hw:
	free_irq(priv->irq, netdev);
err_irq:
	ftmac100_free_buffers(priv);
err_alloc:
	return err;
}

static int ftmac100_stop(struct net_device *netdev)
{
	struct ftmac100 *priv = netdev_priv(netdev);

	ftmac100_disable_all_int(priv);
	netif_stop_queue(netdev);
	napi_disable(&priv->napi);
	ftmac100_stop_hw(priv);
	free_irq(priv->irq, netdev);
	ftmac100_free_buffers(priv);

	return 0;
}

static int ftmac100_hard_start_xmit(struct sk_buff *skb, struct net_device *netdev)
{
	struct ftmac100 *priv = netdev_priv(netdev);
	dma_addr_t map;

	if (unlikely(skb->len > MAX_PKT_SIZE)) {
		if (net_ratelimit())
			netdev_dbg(netdev, "tx packet too big\n");

		netdev->stats.tx_dropped++;
		dev_kfree_skb(skb);
		return NETDEV_TX_OK;
	}

	map = dma_map_single(priv->dev, skb->data, skb_headlen(skb), DMA_TO_DEVICE);
	if (unlikely(dma_mapping_error(priv->dev, map))) {
		/* drop packet */
		if (net_ratelimit())
			netdev_err(netdev, "map socket buffer failed\n");

		netdev->stats.tx_dropped++;
		dev_kfree_skb(skb);
		return NETDEV_TX_OK;
	}

	return ftmac100_xmit(priv, skb, map);
}

/* optional */
static int ftmac100_do_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
{
	struct ftmac100 *priv = netdev_priv(netdev);
	struct mii_ioctl_data *data = if_mii(ifr);

	return generic_mii_ioctl(&priv->mii, data, cmd, NULL);
}

static const struct net_device_ops ftmac100_netdev_ops = {
	.ndo_open		= ftmac100_open,
	.ndo_stop		= ftmac100_stop,
	.ndo_start_xmit		= ftmac100_hard_start_xmit,
	.ndo_set_mac_address	= eth_mac_addr,
	.ndo_validate_addr	= eth_validate_addr,
	.ndo_do_ioctl		= ftmac100_do_ioctl,
};

/******************************************************************************
 * struct platform_driver functions
 *****************************************************************************/
static int ftmac100_probe(struct platform_device *pdev)
{
	struct resource *res;
	int irq;
	struct net_device *netdev;
	struct ftmac100 *priv;
	int err;

	if (!pdev)
		return -ENODEV;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENXIO;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	/* setup net_device */
	netdev = alloc_etherdev(sizeof(*priv));
	if (!netdev) {
		err = -ENOMEM;
		goto err_alloc_etherdev;
	}

	SET_NETDEV_DEV(netdev, &pdev->dev);
	SET_ETHTOOL_OPS(netdev, &ftmac100_ethtool_ops);
	netdev->netdev_ops = &ftmac100_netdev_ops;

	platform_set_drvdata(pdev, netdev);

	/* setup private data */
	priv = netdev_priv(netdev);
	priv->netdev = netdev;
	priv->dev = &pdev->dev;

	spin_lock_init(&priv->tx_lock);

	/* initialize NAPI */
	netif_napi_add(netdev, &priv->napi, ftmac100_poll, 64);

	/* map io memory */
	priv->res = request_mem_region(res->start, resource_size(res),
				       dev_name(&pdev->dev));
	if (!priv->res) {
		dev_err(&pdev->dev, "Could not reserve memory region\n");
		err = -ENOMEM;
		goto err_req_mem;
	}

	priv->base = ioremap(res->start, resource_size(res));
	if (!priv->base) {
		dev_err(&pdev->dev, "Failed to ioremap ethernet registers\n");
		err = -EIO;
		goto err_ioremap;
	}

	priv->irq = irq;

	/* initialize struct mii_if_info */
	priv->mii.phy_id	= 0;
	priv->mii.phy_id_mask	= 0x1f;
	priv->mii.reg_num_mask	= 0x1f;
	priv->mii.dev		= netdev;
	priv->mii.mdio_read	= ftmac100_mdio_read;
	priv->mii.mdio_write	= ftmac100_mdio_write;

	/* register network device */
	err = register_netdev(netdev);
	if (err) {
		dev_err(&pdev->dev, "Failed to register netdev\n");
		goto err_register_netdev;
	}

	netdev_info(netdev, "irq %d, mapped at %p\n", priv->irq, priv->base);

	if (!is_valid_ether_addr(netdev->dev_addr)) {
		random_ether_addr(netdev->dev_addr);
		netdev_info(netdev, "generated random MAC address %pM\n",
			    netdev->dev_addr);
	}

	return 0;

err_register_netdev:
	iounmap(priv->base);
err_ioremap:
	release_resource(priv->res);
err_req_mem:
	netif_napi_del(&priv->napi);
	platform_set_drvdata(pdev, NULL);
	free_netdev(netdev);
err_alloc_etherdev:
	return err;
}

static int __exit ftmac100_remove(struct platform_device *pdev)
{
	struct net_device *netdev;
	struct ftmac100 *priv;

	netdev = platform_get_drvdata(pdev);
	priv = netdev_priv(netdev);

	unregister_netdev(netdev);

	iounmap(priv->base);
	release_resource(priv->res);

	netif_napi_del(&priv->napi);
	platform_set_drvdata(pdev, NULL);
	free_netdev(netdev);
	return 0;
}

static struct platform_driver ftmac100_driver = {
	.probe		= ftmac100_probe,
	.remove		= __exit_p(ftmac100_remove),
	.driver		= {
		.name	= DRV_NAME,
		.owner	= THIS_MODULE,
	},
};

/******************************************************************************
 * initialization / finalization
 *****************************************************************************/
static int __init ftmac100_init(void)
{
	pr_info("Loading version " DRV_VERSION " ...\n");
	return platform_driver_register(&ftmac100_driver);
}

static void __exit ftmac100_exit(void)
{
	platform_driver_unregister(&ftmac100_driver);
}

module_init(ftmac100_init);
module_exit(ftmac100_exit);

MODULE_AUTHOR("Po-Yu Chuang <ratbert@faraday-tech.com>");
MODULE_DESCRIPTION("FTMAC100 driver");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud