aboutsummaryrefslogtreecommitdiff
path: root/drivers/net/ethernet/qualcomm/qca_spi.c
blob: 9c236298fe2125cf26afef756cfd5f3f7250098b (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
/*
 *   Copyright (c) 2011, 2012, Qualcomm Atheros Communications Inc.
 *   Copyright (c) 2014, I2SE GmbH
 *
 *   Permission to use, copy, modify, and/or distribute this software
 *   for any purpose with or without fee is hereby granted, provided
 *   that the above copyright notice and this permission notice appear
 *   in all copies.
 *
 *   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
 *   WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
 *   WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 *   THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
 *   CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 *   LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 *   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 *   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*   This module implements the Qualcomm Atheros SPI protocol for
 *   kernel-based SPI device; it is essentially an Ethernet-to-SPI
 *   serial converter;
 */

#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/netdevice.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_net.h>
#include <linux/sched.h>
#include <linux/skbuff.h>
#include <linux/spi/spi.h>
#include <linux/types.h>

#include "qca_7k.h"
#include "qca_7k_common.h"
#include "qca_debug.h"
#include "qca_spi.h"

#define MAX_DMA_BURST_LEN 5000

/*   Modules parameters     */
#define QCASPI_CLK_SPEED_MIN 1000000
#define QCASPI_CLK_SPEED_MAX 16000000
#define QCASPI_CLK_SPEED     8000000
static int qcaspi_clkspeed;
module_param(qcaspi_clkspeed, int, 0);
MODULE_PARM_DESC(qcaspi_clkspeed, "SPI bus clock speed (Hz). Use 1000000-16000000.");

#define QCASPI_BURST_LEN_MIN 1
#define QCASPI_BURST_LEN_MAX MAX_DMA_BURST_LEN
static int qcaspi_burst_len = MAX_DMA_BURST_LEN;
module_param(qcaspi_burst_len, int, 0);
MODULE_PARM_DESC(qcaspi_burst_len, "Number of data bytes per burst. Use 1-5000.");

#define QCASPI_PLUGGABLE_MIN 0
#define QCASPI_PLUGGABLE_MAX 1
static int qcaspi_pluggable = QCASPI_PLUGGABLE_MIN;
module_param(qcaspi_pluggable, int, 0);
MODULE_PARM_DESC(qcaspi_pluggable, "Pluggable SPI connection (yes/no).");

#define QCASPI_TX_TIMEOUT (1 * HZ)
#define QCASPI_QCA7K_REBOOT_TIME_MS 1000

static void
start_spi_intr_handling(struct qcaspi *qca, u16 *intr_cause)
{
	*intr_cause = 0;

	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0);
	qcaspi_read_register(qca, SPI_REG_INTR_CAUSE, intr_cause);
	netdev_dbg(qca->net_dev, "interrupts: 0x%04x\n", *intr_cause);
}

static void
end_spi_intr_handling(struct qcaspi *qca, u16 intr_cause)
{
	u16 intr_enable = (SPI_INT_CPU_ON |
			   SPI_INT_PKT_AVLBL |
			   SPI_INT_RDBUF_ERR |
			   SPI_INT_WRBUF_ERR);

	qcaspi_write_register(qca, SPI_REG_INTR_CAUSE, intr_cause);
	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, intr_enable);
	netdev_dbg(qca->net_dev, "acking int: 0x%04x\n", intr_cause);
}

static u32
qcaspi_write_burst(struct qcaspi *qca, u8 *src, u32 len)
{
	__be16 cmd;
	struct spi_message *msg = &qca->spi_msg2;
	struct spi_transfer *transfer = &qca->spi_xfer2[0];
	int ret;

	cmd = cpu_to_be16(QCA7K_SPI_WRITE | QCA7K_SPI_EXTERNAL);
	transfer->tx_buf = &cmd;
	transfer->rx_buf = NULL;
	transfer->len = QCASPI_CMD_LEN;
	transfer = &qca->spi_xfer2[1];
	transfer->tx_buf = src;
	transfer->rx_buf = NULL;
	transfer->len = len;

	ret = spi_sync(qca->spi_dev, msg);

	if (ret || (msg->actual_length != QCASPI_CMD_LEN + len)) {
		qcaspi_spi_error(qca);
		return 0;
	}

	return len;
}

static u32
qcaspi_write_legacy(struct qcaspi *qca, u8 *src, u32 len)
{
	struct spi_message *msg = &qca->spi_msg1;
	struct spi_transfer *transfer = &qca->spi_xfer1;
	int ret;

	transfer->tx_buf = src;
	transfer->rx_buf = NULL;
	transfer->len = len;

	ret = spi_sync(qca->spi_dev, msg);

	if (ret || (msg->actual_length != len)) {
		qcaspi_spi_error(qca);
		return 0;
	}

	return len;
}

static u32
qcaspi_read_burst(struct qcaspi *qca, u8 *dst, u32 len)
{
	struct spi_message *msg = &qca->spi_msg2;
	__be16 cmd;
	struct spi_transfer *transfer = &qca->spi_xfer2[0];
	int ret;

	cmd = cpu_to_be16(QCA7K_SPI_READ | QCA7K_SPI_EXTERNAL);
	transfer->tx_buf = &cmd;
	transfer->rx_buf = NULL;
	transfer->len = QCASPI_CMD_LEN;
	transfer = &qca->spi_xfer2[1];
	transfer->tx_buf = NULL;
	transfer->rx_buf = dst;
	transfer->len = len;

	ret = spi_sync(qca->spi_dev, msg);

	if (ret || (msg->actual_length != QCASPI_CMD_LEN + len)) {
		qcaspi_spi_error(qca);
		return 0;
	}

	return len;
}

static u32
qcaspi_read_legacy(struct qcaspi *qca, u8 *dst, u32 len)
{
	struct spi_message *msg = &qca->spi_msg1;
	struct spi_transfer *transfer = &qca->spi_xfer1;
	int ret;

	transfer->tx_buf = NULL;
	transfer->rx_buf = dst;
	transfer->len = len;

	ret = spi_sync(qca->spi_dev, msg);

	if (ret || (msg->actual_length != len)) {
		qcaspi_spi_error(qca);
		return 0;
	}

	return len;
}

static int
qcaspi_tx_cmd(struct qcaspi *qca, u16 cmd)
{
	__be16 tx_data;
	struct spi_message *msg = &qca->spi_msg1;
	struct spi_transfer *transfer = &qca->spi_xfer1;
	int ret;

	tx_data = cpu_to_be16(cmd);
	transfer->len = sizeof(tx_data);
	transfer->tx_buf = &tx_data;
	transfer->rx_buf = NULL;

	ret = spi_sync(qca->spi_dev, msg);

	if (!ret)
		ret = msg->status;

	if (ret)
		qcaspi_spi_error(qca);

	return ret;
}

static int
qcaspi_tx_frame(struct qcaspi *qca, struct sk_buff *skb)
{
	u32 count;
	u32 written;
	u32 offset;
	u32 len;

	len = skb->len;

	qcaspi_write_register(qca, SPI_REG_BFR_SIZE, len);
	if (qca->legacy_mode)
		qcaspi_tx_cmd(qca, QCA7K_SPI_WRITE | QCA7K_SPI_EXTERNAL);

	offset = 0;
	while (len) {
		count = len;
		if (count > qca->burst_len)
			count = qca->burst_len;

		if (qca->legacy_mode) {
			written = qcaspi_write_legacy(qca,
						      skb->data + offset,
						      count);
		} else {
			written = qcaspi_write_burst(qca,
						     skb->data + offset,
						     count);
		}

		if (written != count)
			return -1;

		offset += count;
		len -= count;
	}

	return 0;
}

static int
qcaspi_transmit(struct qcaspi *qca)
{
	struct net_device_stats *n_stats = &qca->net_dev->stats;
	u16 available = 0;
	u32 pkt_len;
	u16 new_head;
	u16 packets = 0;

	if (qca->txr.skb[qca->txr.head] == NULL)
		return 0;

	qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA, &available);

	while (qca->txr.skb[qca->txr.head]) {
		pkt_len = qca->txr.skb[qca->txr.head]->len + QCASPI_HW_PKT_LEN;

		if (available < pkt_len) {
			if (packets == 0)
				qca->stats.write_buf_miss++;
			break;
		}

		if (qcaspi_tx_frame(qca, qca->txr.skb[qca->txr.head]) == -1) {
			qca->stats.write_err++;
			return -1;
		}

		packets++;
		n_stats->tx_packets++;
		n_stats->tx_bytes += qca->txr.skb[qca->txr.head]->len;
		available -= pkt_len;

		/* remove the skb from the queue */
		/* XXX After inconsistent lock states netif_tx_lock()
		 * has been replaced by netif_tx_lock_bh() and so on.
		 */
		netif_tx_lock_bh(qca->net_dev);
		dev_kfree_skb(qca->txr.skb[qca->txr.head]);
		qca->txr.skb[qca->txr.head] = NULL;
		qca->txr.size -= pkt_len;
		new_head = qca->txr.head + 1;
		if (new_head >= qca->txr.count)
			new_head = 0;
		qca->txr.head = new_head;
		if (netif_queue_stopped(qca->net_dev))
			netif_wake_queue(qca->net_dev);
		netif_tx_unlock_bh(qca->net_dev);
	}

	return 0;
}

static int
qcaspi_receive(struct qcaspi *qca)
{
	struct net_device *net_dev = qca->net_dev;
	struct net_device_stats *n_stats = &net_dev->stats;
	u16 available = 0;
	u32 bytes_read;
	u8 *cp;

	/* Allocate rx SKB if we don't have one available. */
	if (!qca->rx_skb) {
		qca->rx_skb = netdev_alloc_skb_ip_align(net_dev,
							net_dev->mtu +
							VLAN_ETH_HLEN);
		if (!qca->rx_skb) {
			netdev_dbg(net_dev, "out of RX resources\n");
			qca->stats.out_of_mem++;
			return -1;
		}
	}

	/* Read the packet size. */
	qcaspi_read_register(qca, SPI_REG_RDBUF_BYTE_AVA, &available);
	netdev_dbg(net_dev, "qcaspi_receive: SPI_REG_RDBUF_BYTE_AVA: Value: %08x\n",
		   available);

	if (available == 0) {
		netdev_dbg(net_dev, "qcaspi_receive called without any data being available!\n");
		return -1;
	}

	qcaspi_write_register(qca, SPI_REG_BFR_SIZE, available);

	if (qca->legacy_mode)
		qcaspi_tx_cmd(qca, QCA7K_SPI_READ | QCA7K_SPI_EXTERNAL);

	while (available) {
		u32 count = available;

		if (count > qca->burst_len)
			count = qca->burst_len;

		if (qca->legacy_mode) {
			bytes_read = qcaspi_read_legacy(qca, qca->rx_buffer,
							count);
		} else {
			bytes_read = qcaspi_read_burst(qca, qca->rx_buffer,
						       count);
		}

		netdev_dbg(net_dev, "available: %d, byte read: %d\n",
			   available, bytes_read);

		if (bytes_read) {
			available -= bytes_read;
		} else {
			qca->stats.read_err++;
			return -1;
		}

		cp = qca->rx_buffer;

		while ((bytes_read--) && (qca->rx_skb)) {
			s32 retcode;

			retcode = qcafrm_fsm_decode(&qca->frm_handle,
						    qca->rx_skb->data,
						    skb_tailroom(qca->rx_skb),
						    *cp);
			cp++;
			switch (retcode) {
			case QCAFRM_GATHER:
			case QCAFRM_NOHEAD:
				break;
			case QCAFRM_NOTAIL:
				netdev_dbg(net_dev, "no RX tail\n");
				n_stats->rx_errors++;
				n_stats->rx_dropped++;
				break;
			case QCAFRM_INVLEN:
				netdev_dbg(net_dev, "invalid RX length\n");
				n_stats->rx_errors++;
				n_stats->rx_dropped++;
				break;
			default:
				qca->rx_skb->dev = qca->net_dev;
				n_stats->rx_packets++;
				n_stats->rx_bytes += retcode;
				skb_put(qca->rx_skb, retcode);
				qca->rx_skb->protocol = eth_type_trans(
					qca->rx_skb, qca->rx_skb->dev);
				qca->rx_skb->ip_summed = CHECKSUM_UNNECESSARY;
				netif_rx_ni(qca->rx_skb);
				qca->rx_skb = netdev_alloc_skb_ip_align(net_dev,
					net_dev->mtu + VLAN_ETH_HLEN);
				if (!qca->rx_skb) {
					netdev_dbg(net_dev, "out of RX resources\n");
					n_stats->rx_errors++;
					qca->stats.out_of_mem++;
					break;
				}
			}
		}
	}

	return 0;
}

/*   Check that tx ring stores only so much bytes
 *   that fit into the internal QCA buffer.
 */

static int
qcaspi_tx_ring_has_space(struct tx_ring *txr)
{
	if (txr->skb[txr->tail])
		return 0;

	return (txr->size + QCAFRM_MAX_LEN < QCASPI_HW_BUF_LEN) ? 1 : 0;
}

/*   Flush the tx ring. This function is only safe to
 *   call from the qcaspi_spi_thread.
 */

static void
qcaspi_flush_tx_ring(struct qcaspi *qca)
{
	int i;

	/* XXX After inconsistent lock states netif_tx_lock()
	 * has been replaced by netif_tx_lock_bh() and so on.
	 */
	netif_tx_lock_bh(qca->net_dev);
	for (i = 0; i < TX_RING_MAX_LEN; i++) {
		if (qca->txr.skb[i]) {
			dev_kfree_skb(qca->txr.skb[i]);
			qca->txr.skb[i] = NULL;
			qca->net_dev->stats.tx_dropped++;
		}
	}
	qca->txr.tail = 0;
	qca->txr.head = 0;
	qca->txr.size = 0;
	netif_tx_unlock_bh(qca->net_dev);
}

static void
qcaspi_qca7k_sync(struct qcaspi *qca, int event)
{
	u16 signature = 0;
	u16 spi_config;
	u16 wrbuf_space = 0;
	static u16 reset_count;

	if (event == QCASPI_EVENT_CPUON) {
		/* Read signature twice, if not valid
		 * go back to unknown state.
		 */
		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
		if (signature != QCASPI_GOOD_SIGNATURE) {
			qca->sync = QCASPI_SYNC_UNKNOWN;
			netdev_dbg(qca->net_dev, "sync: got CPU on, but signature was invalid, restart\n");
		} else {
			/* ensure that the WRBUF is empty */
			qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA,
					     &wrbuf_space);
			if (wrbuf_space != QCASPI_HW_BUF_LEN) {
				netdev_dbg(qca->net_dev, "sync: got CPU on, but wrbuf not empty. reset!\n");
				qca->sync = QCASPI_SYNC_UNKNOWN;
			} else {
				netdev_dbg(qca->net_dev, "sync: got CPU on, now in sync\n");
				qca->sync = QCASPI_SYNC_READY;
				return;
			}
		}
	}

	switch (qca->sync) {
	case QCASPI_SYNC_READY:
		/* Read signature, if not valid go to unknown state. */
		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
		if (signature != QCASPI_GOOD_SIGNATURE) {
			qca->sync = QCASPI_SYNC_UNKNOWN;
			netdev_dbg(qca->net_dev, "sync: bad signature, restart\n");
			/* don't reset right away */
			return;
		}
		break;
	case QCASPI_SYNC_UNKNOWN:
		/* Read signature, if not valid stay in unknown state */
		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
		if (signature != QCASPI_GOOD_SIGNATURE) {
			netdev_dbg(qca->net_dev, "sync: could not read signature to reset device, retry.\n");
			return;
		}

		/* TODO: use GPIO to reset QCA7000 in legacy mode*/
		netdev_dbg(qca->net_dev, "sync: resetting device.\n");
		qcaspi_read_register(qca, SPI_REG_SPI_CONFIG, &spi_config);
		spi_config |= QCASPI_SLAVE_RESET_BIT;
		qcaspi_write_register(qca, SPI_REG_SPI_CONFIG, spi_config);

		qca->sync = QCASPI_SYNC_RESET;
		qca->stats.trig_reset++;
		reset_count = 0;
		break;
	case QCASPI_SYNC_RESET:
		reset_count++;
		netdev_dbg(qca->net_dev, "sync: waiting for CPU on, count %u.\n",
			   reset_count);
		if (reset_count >= QCASPI_RESET_TIMEOUT) {
			/* reset did not seem to take place, try again */
			qca->sync = QCASPI_SYNC_UNKNOWN;
			qca->stats.reset_timeout++;
			netdev_dbg(qca->net_dev, "sync: reset timeout, restarting process.\n");
		}
		break;
	}
}

static int
qcaspi_spi_thread(void *data)
{
	struct qcaspi *qca = data;
	u16 intr_cause = 0;

	netdev_info(qca->net_dev, "SPI thread created\n");
	while (!kthread_should_stop()) {
		set_current_state(TASK_INTERRUPTIBLE);
		if ((qca->intr_req == qca->intr_svc) &&
		    (qca->txr.skb[qca->txr.head] == NULL) &&
		    (qca->sync == QCASPI_SYNC_READY))
			schedule();

		set_current_state(TASK_RUNNING);

		netdev_dbg(qca->net_dev, "have work to do. int: %d, tx_skb: %p\n",
			   qca->intr_req - qca->intr_svc,
			   qca->txr.skb[qca->txr.head]);

		qcaspi_qca7k_sync(qca, QCASPI_EVENT_UPDATE);

		if (qca->sync != QCASPI_SYNC_READY) {
			netdev_dbg(qca->net_dev, "sync: not ready %u, turn off carrier and flush\n",
				   (unsigned int)qca->sync);
			netif_stop_queue(qca->net_dev);
			netif_carrier_off(qca->net_dev);
			qcaspi_flush_tx_ring(qca);
			msleep(QCASPI_QCA7K_REBOOT_TIME_MS);
		}

		if (qca->intr_svc != qca->intr_req) {
			qca->intr_svc = qca->intr_req;
			start_spi_intr_handling(qca, &intr_cause);

			if (intr_cause & SPI_INT_CPU_ON) {
				qcaspi_qca7k_sync(qca, QCASPI_EVENT_CPUON);

				/* not synced. */
				if (qca->sync != QCASPI_SYNC_READY)
					continue;

				qca->stats.device_reset++;
				netif_wake_queue(qca->net_dev);
				netif_carrier_on(qca->net_dev);
			}

			if (intr_cause & SPI_INT_RDBUF_ERR) {
				/* restart sync */
				netdev_dbg(qca->net_dev, "===> rdbuf error!\n");
				qca->stats.read_buf_err++;
				qca->sync = QCASPI_SYNC_UNKNOWN;
				continue;
			}

			if (intr_cause & SPI_INT_WRBUF_ERR) {
				/* restart sync */
				netdev_dbg(qca->net_dev, "===> wrbuf error!\n");
				qca->stats.write_buf_err++;
				qca->sync = QCASPI_SYNC_UNKNOWN;
				continue;
			}

			/* can only handle other interrupts
			 * if sync has occurred
			 */
			if (qca->sync == QCASPI_SYNC_READY) {
				if (intr_cause & SPI_INT_PKT_AVLBL)
					qcaspi_receive(qca);
			}

			end_spi_intr_handling(qca, intr_cause);
		}

		if (qca->sync == QCASPI_SYNC_READY)
			qcaspi_transmit(qca);
	}
	set_current_state(TASK_RUNNING);
	netdev_info(qca->net_dev, "SPI thread exit\n");

	return 0;
}

static irqreturn_t
qcaspi_intr_handler(int irq, void *data)
{
	struct qcaspi *qca = data;

	qca->intr_req++;
	if (qca->spi_thread &&
	    qca->spi_thread->state != TASK_RUNNING)
		wake_up_process(qca->spi_thread);

	return IRQ_HANDLED;
}

static int
qcaspi_netdev_open(struct net_device *dev)
{
	struct qcaspi *qca = netdev_priv(dev);
	int ret = 0;

	if (!qca)
		return -EINVAL;

	qca->intr_req = 1;
	qca->intr_svc = 0;
	qca->sync = QCASPI_SYNC_UNKNOWN;
	qcafrm_fsm_init_spi(&qca->frm_handle);

	qca->spi_thread = kthread_run((void *)qcaspi_spi_thread,
				      qca, "%s", dev->name);

	if (IS_ERR(qca->spi_thread)) {
		netdev_err(dev, "%s: unable to start kernel thread.\n",
			   QCASPI_DRV_NAME);
		return PTR_ERR(qca->spi_thread);
	}

	ret = request_irq(qca->spi_dev->irq, qcaspi_intr_handler, 0,
			  dev->name, qca);
	if (ret) {
		netdev_err(dev, "%s: unable to get IRQ %d (irqval=%d).\n",
			   QCASPI_DRV_NAME, qca->spi_dev->irq, ret);
		kthread_stop(qca->spi_thread);
		return ret;
	}

	netif_start_queue(qca->net_dev);

	return 0;
}

static int
qcaspi_netdev_close(struct net_device *dev)
{
	struct qcaspi *qca = netdev_priv(dev);

	netif_stop_queue(dev);

	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0);
	free_irq(qca->spi_dev->irq, qca);

	kthread_stop(qca->spi_thread);
	qca->spi_thread = NULL;
	qcaspi_flush_tx_ring(qca);

	return 0;
}

static netdev_tx_t
qcaspi_netdev_xmit(struct sk_buff *skb, struct net_device *dev)
{
	u32 frame_len;
	u8 *ptmp;
	struct qcaspi *qca = netdev_priv(dev);
	u16 new_tail;
	struct sk_buff *tskb;
	u8 pad_len = 0;

	if (skb->len < QCAFRM_MIN_LEN)
		pad_len = QCAFRM_MIN_LEN - skb->len;

	if (qca->txr.skb[qca->txr.tail]) {
		netdev_warn(qca->net_dev, "queue was unexpectedly full!\n");
		netif_stop_queue(qca->net_dev);
		qca->stats.ring_full++;
		return NETDEV_TX_BUSY;
	}

	if ((skb_headroom(skb) < QCAFRM_HEADER_LEN) ||
	    (skb_tailroom(skb) < QCAFRM_FOOTER_LEN + pad_len)) {
		tskb = skb_copy_expand(skb, QCAFRM_HEADER_LEN,
				       QCAFRM_FOOTER_LEN + pad_len, GFP_ATOMIC);
		if (!tskb) {
			netdev_dbg(qca->net_dev, "could not allocate tx_buff\n");
			qca->stats.out_of_mem++;
			return NETDEV_TX_BUSY;
		}
		dev_kfree_skb(skb);
		skb = tskb;
	}

	frame_len = skb->len + pad_len;

	ptmp = skb_push(skb, QCAFRM_HEADER_LEN);
	qcafrm_create_header(ptmp, frame_len);

	if (pad_len) {
		ptmp = skb_put_zero(skb, pad_len);
	}

	ptmp = skb_put(skb, QCAFRM_FOOTER_LEN);
	qcafrm_create_footer(ptmp);

	netdev_dbg(qca->net_dev, "Tx-ing packet: Size: 0x%08x\n",
		   skb->len);

	qca->txr.size += skb->len + QCASPI_HW_PKT_LEN;

	new_tail = qca->txr.tail + 1;
	if (new_tail >= qca->txr.count)
		new_tail = 0;

	qca->txr.skb[qca->txr.tail] = skb;
	qca->txr.tail = new_tail;

	if (!qcaspi_tx_ring_has_space(&qca->txr)) {
		netif_stop_queue(qca->net_dev);
		qca->stats.ring_full++;
	}

	netif_trans_update(dev);

	if (qca->spi_thread &&
	    qca->spi_thread->state != TASK_RUNNING)
		wake_up_process(qca->spi_thread);

	return NETDEV_TX_OK;
}

static void
qcaspi_netdev_tx_timeout(struct net_device *dev)
{
	struct qcaspi *qca = netdev_priv(dev);

	netdev_info(qca->net_dev, "Transmit timeout at %ld, latency %ld\n",
		    jiffies, jiffies - dev_trans_start(dev));
	qca->net_dev->stats.tx_errors++;
	/* Trigger tx queue flush and QCA7000 reset */
	qca->sync = QCASPI_SYNC_UNKNOWN;
}

static int
qcaspi_netdev_init(struct net_device *dev)
{
	struct qcaspi *qca = netdev_priv(dev);

	dev->mtu = QCAFRM_MAX_MTU;
	dev->type = ARPHRD_ETHER;
	qca->clkspeed = qcaspi_clkspeed;
	qca->burst_len = qcaspi_burst_len;
	qca->spi_thread = NULL;
	qca->buffer_size = (dev->mtu + VLAN_ETH_HLEN + QCAFRM_HEADER_LEN +
		QCAFRM_FOOTER_LEN + 4) * 4;

	memset(&qca->stats, 0, sizeof(struct qcaspi_stats));

	qca->rx_buffer = kmalloc(qca->buffer_size, GFP_KERNEL);
	if (!qca->rx_buffer)
		return -ENOBUFS;

	qca->rx_skb = netdev_alloc_skb_ip_align(dev, qca->net_dev->mtu +
						VLAN_ETH_HLEN);
	if (!qca->rx_skb) {
		kfree(qca->rx_buffer);
		netdev_info(qca->net_dev, "Failed to allocate RX sk_buff.\n");
		return -ENOBUFS;
	}

	return 0;
}

static void
qcaspi_netdev_uninit(struct net_device *dev)
{
	struct qcaspi *qca = netdev_priv(dev);

	kfree(qca->rx_buffer);
	qca->buffer_size = 0;
	if (qca->rx_skb)
		dev_kfree_skb(qca->rx_skb);
}

static const struct net_device_ops qcaspi_netdev_ops = {
	.ndo_init = qcaspi_netdev_init,
	.ndo_uninit = qcaspi_netdev_uninit,
	.ndo_open = qcaspi_netdev_open,
	.ndo_stop = qcaspi_netdev_close,
	.ndo_start_xmit = qcaspi_netdev_xmit,
	.ndo_set_mac_address = eth_mac_addr,
	.ndo_tx_timeout = qcaspi_netdev_tx_timeout,
	.ndo_validate_addr = eth_validate_addr,
};

static void
qcaspi_netdev_setup(struct net_device *dev)
{
	struct qcaspi *qca = NULL;

	dev->netdev_ops = &qcaspi_netdev_ops;
	qcaspi_set_ethtool_ops(dev);
	dev->watchdog_timeo = QCASPI_TX_TIMEOUT;
	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
	dev->tx_queue_len = 100;

	/* MTU range: 46 - 1500 */
	dev->min_mtu = QCAFRM_MIN_MTU;
	dev->max_mtu = QCAFRM_MAX_MTU;

	qca = netdev_priv(dev);
	memset(qca, 0, sizeof(struct qcaspi));

	memset(&qca->spi_xfer1, 0, sizeof(struct spi_transfer));
	memset(&qca->spi_xfer2, 0, sizeof(struct spi_transfer) * 2);

	spi_message_init(&qca->spi_msg1);
	spi_message_add_tail(&qca->spi_xfer1, &qca->spi_msg1);

	spi_message_init(&qca->spi_msg2);
	spi_message_add_tail(&qca->spi_xfer2[0], &qca->spi_msg2);
	spi_message_add_tail(&qca->spi_xfer2[1], &qca->spi_msg2);

	memset(&qca->txr, 0, sizeof(qca->txr));
	qca->txr.count = TX_RING_MAX_LEN;
}

static const struct of_device_id qca_spi_of_match[] = {
	{ .compatible = "qca,qca7000" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, qca_spi_of_match);

static int
qca_spi_probe(struct spi_device *spi)
{
	struct qcaspi *qca = NULL;
	struct net_device *qcaspi_devs = NULL;
	u8 legacy_mode = 0;
	u16 signature;
	const char *mac;

	if (!spi->dev.of_node) {
		dev_err(&spi->dev, "Missing device tree\n");
		return -EINVAL;
	}

	legacy_mode = of_property_read_bool(spi->dev.of_node,
					    "qca,legacy-mode");

	if (qcaspi_clkspeed == 0) {
		if (spi->max_speed_hz)
			qcaspi_clkspeed = spi->max_speed_hz;
		else
			qcaspi_clkspeed = QCASPI_CLK_SPEED;
	}

	if ((qcaspi_clkspeed < QCASPI_CLK_SPEED_MIN) ||
	    (qcaspi_clkspeed > QCASPI_CLK_SPEED_MAX)) {
		dev_info(&spi->dev, "Invalid clkspeed: %d\n",
			 qcaspi_clkspeed);
		return -EINVAL;
	}

	if ((qcaspi_burst_len < QCASPI_BURST_LEN_MIN) ||
	    (qcaspi_burst_len > QCASPI_BURST_LEN_MAX)) {
		dev_info(&spi->dev, "Invalid burst len: %d\n",
			 qcaspi_burst_len);
		return -EINVAL;
	}

	if ((qcaspi_pluggable < QCASPI_PLUGGABLE_MIN) ||
	    (qcaspi_pluggable > QCASPI_PLUGGABLE_MAX)) {
		dev_info(&spi->dev, "Invalid pluggable: %d\n",
			 qcaspi_pluggable);
		return -EINVAL;
	}

	dev_info(&spi->dev, "ver=%s, clkspeed=%d, burst_len=%d, pluggable=%d\n",
		 QCASPI_DRV_VERSION,
		 qcaspi_clkspeed,
		 qcaspi_burst_len,
		 qcaspi_pluggable);

	spi->mode = SPI_MODE_3;
	spi->max_speed_hz = qcaspi_clkspeed;
	if (spi_setup(spi) < 0) {
		dev_err(&spi->dev, "Unable to setup SPI device\n");
		return -EFAULT;
	}

	qcaspi_devs = alloc_etherdev(sizeof(struct qcaspi));
	if (!qcaspi_devs)
		return -ENOMEM;

	qcaspi_netdev_setup(qcaspi_devs);
	SET_NETDEV_DEV(qcaspi_devs, &spi->dev);

	qca = netdev_priv(qcaspi_devs);
	if (!qca) {
		free_netdev(qcaspi_devs);
		dev_err(&spi->dev, "Fail to retrieve private structure\n");
		return -ENOMEM;
	}
	qca->net_dev = qcaspi_devs;
	qca->spi_dev = spi;
	qca->legacy_mode = legacy_mode;

	spi_set_drvdata(spi, qcaspi_devs);

	mac = of_get_mac_address(spi->dev.of_node);

	if (mac)
		ether_addr_copy(qca->net_dev->dev_addr, mac);

	if (!is_valid_ether_addr(qca->net_dev->dev_addr)) {
		eth_hw_addr_random(qca->net_dev);
		dev_info(&spi->dev, "Using random MAC address: %pM\n",
			 qca->net_dev->dev_addr);
	}

	netif_carrier_off(qca->net_dev);

	if (!qcaspi_pluggable) {
		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);

		if (signature != QCASPI_GOOD_SIGNATURE) {
			dev_err(&spi->dev, "Invalid signature (0x%04X)\n",
				signature);
			free_netdev(qcaspi_devs);
			return -EFAULT;
		}
	}

	if (register_netdev(qcaspi_devs)) {
		dev_info(&spi->dev, "Unable to register net device %s\n",
			 qcaspi_devs->name);
		free_netdev(qcaspi_devs);
		return -EFAULT;
	}

	qcaspi_init_device_debugfs(qca);

	return 0;
}

static int
qca_spi_remove(struct spi_device *spi)
{
	struct net_device *qcaspi_devs = spi_get_drvdata(spi);
	struct qcaspi *qca = netdev_priv(qcaspi_devs);

	qcaspi_remove_device_debugfs(qca);

	unregister_netdev(qcaspi_devs);
	free_netdev(qcaspi_devs);

	return 0;
}

static const struct spi_device_id qca_spi_id[] = {
	{ "qca7000", 0 },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(spi, qca_spi_id);

static struct spi_driver qca_spi_driver = {
	.driver	= {
		.name	= QCASPI_DRV_NAME,
		.of_match_table = qca_spi_of_match,
	},
	.id_table = qca_spi_id,
	.probe    = qca_spi_probe,
	.remove   = qca_spi_remove,
};
module_spi_driver(qca_spi_driver);

MODULE_DESCRIPTION("Qualcomm Atheros QCA7000 SPI Driver");
MODULE_AUTHOR("Qualcomm Atheros Communications");
MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_VERSION(QCASPI_DRV_VERSION);