aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/meth.c
blob: e23655f5049fa340ba432fc3ecb4fb90b1bd3d1e (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
/*
 * meth.c -- O2 Builtin 10/100 Ethernet driver
 *
 * Copyright (C) 2001-2003 Ilya Volynets
 *
 *	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.
 */
#include <linux/module.h>
#include <linux/init.h>

#include <linux/sched.h>
#include <linux/kernel.h> /* printk() */
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/errno.h>  /* error codes */
#include <linux/types.h>  /* size_t */
#include <linux/interrupt.h> /* mark_bh */

#include <linux/in.h>
#include <linux/in6.h>
#include <linux/device.h> /* struct device, et al */
#include <linux/netdevice.h>   /* struct device, and other headers */
#include <linux/etherdevice.h> /* eth_type_trans */
#include <linux/ip.h>          /* struct iphdr */
#include <linux/tcp.h>         /* struct tcphdr */
#include <linux/skbuff.h>
#include <linux/mii.h>         /* MII definitions */

#include <asm/ip32/mace.h>
#include <asm/ip32/ip32_ints.h>

#include <asm/io.h>
#include <asm/checksum.h>
#include <asm/scatterlist.h>
#include <linux/dma-mapping.h>

#include "meth.h"

#ifndef MFE_DEBUG
#define MFE_DEBUG 0
#endif

#if MFE_DEBUG>=1
#define DPRINTK(str,args...) printk(KERN_DEBUG "meth: %s: " str, __FUNCTION__ , ## args)
#define MFE_RX_DEBUG 2
#else
#define DPRINTK(str,args...)
#define MFE_RX_DEBUG 0
#endif


static const char *meth_str="SGI O2 Fast Ethernet";
MODULE_AUTHOR("Ilya Volynets <ilya@theIlya.com>");
MODULE_DESCRIPTION("SGI O2 Builtin Fast Ethernet driver");

#define HAVE_TX_TIMEOUT
/* The maximum time waited (in jiffies) before assuming a Tx failed. (400ms) */
#define TX_TIMEOUT (400*HZ/1000)

#ifdef HAVE_TX_TIMEOUT
static int timeout = TX_TIMEOUT;
MODULE_PARM(timeout, "i");
#endif

/*
 * This structure is private to each device. It is used to pass
 * packets in and out, so there is place for a packet
 */
struct meth_private {
	struct net_device_stats stats;
	/* in-memory copy of MAC Control register */
	unsigned long mac_ctrl;
	/* in-memory copy of DMA Control register */
	unsigned long dma_ctrl;
	/* address of PHY, used by mdio_* functions, initialized in mdio_probe */
	unsigned long phy_addr;
	tx_packet *tx_ring;
	dma_addr_t tx_ring_dma;
	struct sk_buff *tx_skbs[TX_RING_ENTRIES];
	dma_addr_t tx_skb_dmas[TX_RING_ENTRIES];
	unsigned long tx_read, tx_write, tx_count;

	rx_packet *rx_ring[RX_RING_ENTRIES];
	dma_addr_t rx_ring_dmas[RX_RING_ENTRIES];
	struct sk_buff *rx_skbs[RX_RING_ENTRIES];
	unsigned long rx_write;

	spinlock_t meth_lock;
};

static void meth_tx_timeout(struct net_device *dev);
static irqreturn_t meth_interrupt(int irq, void *dev_id, struct pt_regs *pregs);
        
/* global, initialized in ip32-setup.c */
char o2meth_eaddr[8]={0,0,0,0,0,0,0,0};

static inline void load_eaddr(struct net_device *dev)
{
	int i;
	DPRINTK("Loading MAC Address: %02x:%02x:%02x:%02x:%02x:%02x\n",
		(int)o2meth_eaddr[0]&0xFF,(int)o2meth_eaddr[1]&0xFF,(int)o2meth_eaddr[2]&0xFF,
		(int)o2meth_eaddr[3]&0xFF,(int)o2meth_eaddr[4]&0xFF,(int)o2meth_eaddr[5]&0xFF);
	for (i = 0; i < 6; i++)
		dev->dev_addr[i] = o2meth_eaddr[i];
	mace->eth.mac_addr = (*(unsigned long*)o2meth_eaddr) >> 16;
}

/*
 * Waits for BUSY status of mdio bus to clear
 */
#define WAIT_FOR_PHY(___rval)					\
	while ((___rval = mace->eth.phy_data) & MDIO_BUSY) {	\
		udelay(25);					\
	}
/*read phy register, return value read */
static unsigned long mdio_read(struct meth_private *priv, unsigned long phyreg)
{
	unsigned long rval;
	WAIT_FOR_PHY(rval);
	mace->eth.phy_regs = (priv->phy_addr << 5) | (phyreg & 0x1f);
	udelay(25);
	mace->eth.phy_trans_go = 1;
	udelay(25);
	WAIT_FOR_PHY(rval);
	return rval & MDIO_DATA_MASK;
}

static int mdio_probe(struct meth_private *priv)
{
	int i;
	unsigned long p2, p3;
	/* check if phy is detected already */
	if(priv->phy_addr>=0&&priv->phy_addr<32)
		return 0;
	spin_lock(&priv->meth_lock);
	for (i=0;i<32;++i){
		priv->phy_addr=i;
		p2=mdio_read(priv,2);
		p3=mdio_read(priv,3);
#if MFE_DEBUG>=2
		switch ((p2<<12)|(p3>>4)){
		case PHY_QS6612X:
			DPRINTK("PHY is QS6612X\n");
			break;
		case PHY_ICS1889:
			DPRINTK("PHY is ICS1889\n");
			break;
		case PHY_ICS1890:
			DPRINTK("PHY is ICS1890\n");
			break;
		case PHY_DP83840:
			DPRINTK("PHY is DP83840\n");
			break;
		}
#endif
		if(p2!=0xffff&&p2!=0x0000){
			DPRINTK("PHY code: %x\n",(p2<<12)|(p3>>4));
			break;
		}
	}
	spin_unlock(&priv->meth_lock);
	if(priv->phy_addr<32) {
		return 0;
	}
	DPRINTK("Oopsie! PHY is not known!\n");
	priv->phy_addr=-1;
	return -ENODEV;
}

static void meth_check_link(struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;
	unsigned long mii_advertising = mdio_read(priv, 4);
	unsigned long mii_partner = mdio_read(priv, 5);
	unsigned long negotiated = mii_advertising & mii_partner;
	unsigned long duplex, speed;

	if (mii_partner == 0xffff)
		return;

	speed = (negotiated & 0x0380) ? METH_100MBIT : 0;
	duplex = ((negotiated & 0x0100) || (negotiated & 0x01C0) == 0x0040) ?
		 METH_PHY_FDX : 0;

	if ((priv->mac_ctrl & METH_PHY_FDX) ^ duplex) {
		DPRINTK("Setting %s-duplex\n", duplex ? "full" : "half");
		if (duplex)
			priv->mac_ctrl |= METH_PHY_FDX;
		else
			priv->mac_ctrl &= ~METH_PHY_FDX;
		mace->eth.mac_ctrl = priv->mac_ctrl;
	}

	if ((priv->mac_ctrl & METH_100MBIT) ^ speed) {
		DPRINTK("Setting %dMbs mode\n", speed ? 100 : 10);
		if (duplex)
			priv->mac_ctrl |= METH_100MBIT;
		else
			priv->mac_ctrl &= ~METH_100MBIT;
		mace->eth.mac_ctrl = priv->mac_ctrl;
	}
}


static int meth_init_tx_ring(struct meth_private *priv)
{
	/* Init TX ring */
	priv->tx_ring = dma_alloc_coherent(NULL, TX_RING_BUFFER_SIZE,
	                                   &priv->tx_ring_dma, GFP_ATOMIC);
	if (!priv->tx_ring)
		return -ENOMEM;
	memset(priv->tx_ring, 0, TX_RING_BUFFER_SIZE);
	priv->tx_count = priv->tx_read = priv->tx_write = 0;
	mace->eth.tx_ring_base = priv->tx_ring_dma;
	/* Now init skb save area */
	memset(priv->tx_skbs, 0, sizeof(priv->tx_skbs));
	memset(priv->tx_skb_dmas, 0, sizeof(priv->tx_skb_dmas));
	return 0;
}

static int meth_init_rx_ring(struct meth_private *priv)
{
	int i;

	for (i = 0; i < RX_RING_ENTRIES; i++) {
		priv->rx_skbs[i] = alloc_skb(METH_RX_BUFF_SIZE, 0);
		/* 8byte status vector + 3quad padding + 2byte padding,
		 * to put data on 64bit aligned boundary */
		skb_reserve(priv->rx_skbs[i],METH_RX_HEAD);
		priv->rx_ring[i]=(rx_packet*)(priv->rx_skbs[i]->head);
		/* I'll need to re-sync it after each RX */
		priv->rx_ring_dmas[i] = 
			dma_map_single(NULL, priv->rx_ring[i],
				       METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
		mace->eth.rx_fifo = priv->rx_ring_dmas[i];
	}
        priv->rx_write = 0;
	return 0;
}
static void meth_free_tx_ring(struct meth_private *priv)
{
	int i;

	/* Remove any pending skb */
	for (i = 0; i < TX_RING_ENTRIES; i++) {
		if (priv->tx_skbs[i])
			dev_kfree_skb(priv->tx_skbs[i]);
		priv->tx_skbs[i] = NULL;
	}
	dma_free_coherent(NULL, TX_RING_BUFFER_SIZE, priv->tx_ring,
	                  priv->tx_ring_dma);
}

/* Presumes RX DMA engine is stopped, and RX fifo ring is reset */
static void meth_free_rx_ring(struct meth_private *priv)
{
	int i;

	for (i = 0; i < RX_RING_ENTRIES; i++) {
		dma_unmap_single(NULL, priv->rx_ring_dmas[i],
				 METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
		priv->rx_ring[i] = 0;
		priv->rx_ring_dmas[i] = 0;
		kfree_skb(priv->rx_skbs[i]);
	}
}

int meth_reset(struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;

	/* Reset card */
	mace->eth.mac_ctrl = SGI_MAC_RESET;
	udelay(1);
	mace->eth.mac_ctrl = 0;
	udelay(25);

	/* Load ethernet address */
	load_eaddr(dev);
	/* Should load some "errata", but later */
	
	/* Check for device */
	if (mdio_probe(priv) < 0) {
		DPRINTK("Unable to find PHY\n");
		return -ENODEV;
	}

	/* Initial mode: 10 | Half-duplex | Accept normal packets */
	priv->mac_ctrl = METH_ACCEPT_MCAST | METH_DEFAULT_IPG;
	if (dev->flags | IFF_PROMISC)
		priv->mac_ctrl |= METH_PROMISC;
	mace->eth.mac_ctrl = priv->mac_ctrl;

	/* Autonegotiate speed and duplex mode */
	meth_check_link(dev);

	/* Now set dma control, but don't enable DMA, yet */
	priv->dma_ctrl = (4 << METH_RX_OFFSET_SHIFT) |
			 (RX_RING_ENTRIES << METH_RX_DEPTH_SHIFT);
	mace->eth.dma_ctrl = priv->dma_ctrl;

	return 0;
}

/*============End Helper Routines=====================*/

/*
 * Open and close
 */
static int meth_open(struct net_device *dev)
{
	struct meth_private *priv = dev->priv;
	int ret;

	priv->phy_addr = -1;    /* No PHY is known yet... */

	/* Initialize the hardware */
	ret = meth_reset(dev);
	if (ret < 0)
		return ret;

	/* Allocate the ring buffers */
	ret = meth_init_tx_ring(priv);
	if (ret < 0)
		return ret;
	ret = meth_init_rx_ring(priv);
	if (ret < 0)
		goto out_free_tx_ring;

	ret = request_irq(dev->irq, meth_interrupt, 0, meth_str, dev);
	if (ret) {
		printk(KERN_ERR "%s: Can't get irq %d\n", dev->name, dev->irq);
		goto out_free_rx_ring;
	}

	/* Start DMA */
	priv->dma_ctrl |= METH_DMA_TX_EN | /*METH_DMA_TX_INT_EN |*/
			  METH_DMA_RX_EN | METH_DMA_RX_INT_EN;
	mace->eth.dma_ctrl = priv->dma_ctrl;

	DPRINTK("About to start queue\n");
	netif_start_queue(dev);

	return 0;

out_free_rx_ring:
	meth_free_rx_ring(priv);
out_free_tx_ring:
	meth_free_tx_ring(priv);

	return ret;
}

static int meth_release(struct net_device *dev)
{
	struct meth_private *priv = dev->priv;

	DPRINTK("Stopping queue\n");
	netif_stop_queue(dev); /* can't transmit any more */
	/* shut down DMA */
	priv->dma_ctrl &= ~(METH_DMA_TX_EN | METH_DMA_TX_INT_EN |
			    METH_DMA_RX_EN | METH_DMA_RX_INT_EN);
	mace->eth.dma_ctrl = priv->dma_ctrl;
	free_irq(dev->irq, dev);
	meth_free_tx_ring(priv);
	meth_free_rx_ring(priv);

	return 0;
}

/*
 * Receive a packet: retrieve, encapsulate and pass over to upper levels
 */
static void meth_rx(struct net_device* dev, unsigned long int_status)
{
	struct sk_buff *skb;
	unsigned long status;
	struct meth_private *priv = (struct meth_private *) dev->priv;
	unsigned long fifo_rptr = (int_status & METH_INT_RX_RPTR_MASK) >> 8;

	spin_lock(&priv->meth_lock);
	priv->dma_ctrl &= ~METH_DMA_RX_INT_EN;
	mace->eth.dma_ctrl = priv->dma_ctrl;
	spin_unlock(&priv->meth_lock);

	if (int_status & METH_INT_RX_UNDERFLOW) {
		fifo_rptr = (fifo_rptr - 1) & 0x0f;
	}
	while (priv->rx_write != fifo_rptr) {
		dma_unmap_single(NULL, priv->rx_ring_dmas[priv->rx_write],
				 METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
		status = priv->rx_ring[priv->rx_write]->status.raw;
#if MFE_DEBUG
		if (!(status & METH_RX_ST_VALID)) {
			DPRINTK("Not received? status=%016lx\n",status);
		}
#endif
		if ((!(status & METH_RX_STATUS_ERRORS)) && (status & METH_RX_ST_VALID)) {
			int len = (status & 0xffff) - 4; /* omit CRC */
			/* length sanity check */
			if (len < 60 || len > 1518) {
				printk(KERN_DEBUG "%s: bogus packet size: %ld, status=%#2lx.\n",
				       dev->name, priv->rx_write,
				       priv->rx_ring[priv->rx_write]->status.raw);
				priv->stats.rx_errors++;
				priv->stats.rx_length_errors++;
				skb = priv->rx_skbs[priv->rx_write];
			} else {
				skb = alloc_skb(METH_RX_BUFF_SIZE, GFP_ATOMIC | GFP_DMA);
				if (!skb) {
					/* Ouch! No memory! Drop packet on the floor */
					DPRINTK("No mem: dropping packet\n");
					priv->stats.rx_dropped++;
					skb = priv->rx_skbs[priv->rx_write];
				} else {
					struct sk_buff *skb_c = priv->rx_skbs[priv->rx_write];
					/* 8byte status vector + 3quad padding + 2byte padding,
					 * to put data on 64bit aligned boundary */
					skb_reserve(skb, METH_RX_HEAD);
					/* Write metadata, and then pass to the receive level */
					skb_put(skb_c, len);
					priv->rx_skbs[priv->rx_write] = skb;
					skb_c->dev = dev;
					skb_c->protocol = eth_type_trans(skb_c, dev);
					dev->last_rx = jiffies;
					priv->stats.rx_packets++;
					priv->stats.rx_bytes += len;
					netif_rx(skb_c);
				}
			}
		} else {
			priv->stats.rx_errors++;
			skb=priv->rx_skbs[priv->rx_write];
#if MFE_DEBUG>0
			printk(KERN_WARNING "meth: RX error: status=0x%016lx\n",status);
			if(status&METH_RX_ST_RCV_CODE_VIOLATION)
				printk(KERN_WARNING "Receive Code Violation\n");
			if(status&METH_RX_ST_CRC_ERR)
				printk(KERN_WARNING "CRC error\n");
			if(status&METH_RX_ST_INV_PREAMBLE_CTX)
				printk(KERN_WARNING "Invalid Preamble Context\n");
			if(status&METH_RX_ST_LONG_EVT_SEEN)
				printk(KERN_WARNING "Long Event Seen...\n");
			if(status&METH_RX_ST_BAD_PACKET)
				printk(KERN_WARNING "Bad Packet\n");
			if(status&METH_RX_ST_CARRIER_EVT_SEEN)
				printk(KERN_WARNING "Carrier Event Seen\n");
#endif
		}
		priv->rx_ring[priv->rx_write] = (rx_packet*)skb->head;
		priv->rx_ring[priv->rx_write]->status.raw = 0;
		priv->rx_ring_dmas[priv->rx_write] = 
			dma_map_single(NULL, priv->rx_ring[priv->rx_write],
				       METH_RX_BUFF_SIZE, DMA_FROM_DEVICE);
		mace->eth.rx_fifo = priv->rx_ring_dmas[priv->rx_write];
		ADVANCE_RX_PTR(priv->rx_write);
	}
	spin_lock(&priv->meth_lock);
	/* In case there was underflow, and Rx DMA was disabled */
	priv->dma_ctrl |= METH_DMA_RX_INT_EN | METH_DMA_RX_EN;
	mace->eth.dma_ctrl = priv->dma_ctrl;
	mace->eth.int_stat = METH_INT_RX_THRESHOLD;
	spin_unlock(&priv->meth_lock);
}

static int meth_tx_full(struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;

	return (priv->tx_count >= TX_RING_ENTRIES - 1);
}

static void meth_tx_cleanup(struct net_device* dev, unsigned long int_status)
{
	struct meth_private *priv = dev->priv;
	unsigned long status;
	struct sk_buff *skb;
	unsigned long rptr = (int_status&TX_INFO_RPTR) >> 16;

	spin_lock(&priv->meth_lock);

	/* Stop DMA notification */
	priv->dma_ctrl &= ~(METH_DMA_TX_INT_EN);
	mace->eth.dma_ctrl = priv->dma_ctrl;

	while (priv->tx_read != rptr) {
		skb = priv->tx_skbs[priv->tx_read];
		status = priv->tx_ring[priv->tx_read].header.raw;
#if MFE_DEBUG>=1
		if (priv->tx_read == priv->tx_write)
			DPRINTK("Auchi! tx_read=%d,tx_write=%d,rptr=%d?\n", priv->tx_read, priv->tx_write,rptr);
#endif
		if (status & METH_TX_ST_DONE) {
			if (status & METH_TX_ST_SUCCESS){
				priv->stats.tx_packets++;
				priv->stats.tx_bytes += skb->len;
			} else {
				priv->stats.tx_errors++;
#if MFE_DEBUG>=1
				DPRINTK("TX error: status=%016lx <",status);
				if(status & METH_TX_ST_SUCCESS)
					printk(" SUCCESS");
				if(status & METH_TX_ST_TOOLONG)
					printk(" TOOLONG");
				if(status & METH_TX_ST_UNDERRUN)
					printk(" UNDERRUN");
				if(status & METH_TX_ST_EXCCOLL)
					printk(" EXCCOLL");
				if(status & METH_TX_ST_DEFER)
					printk(" DEFER");
				if(status & METH_TX_ST_LATECOLL)
					printk(" LATECOLL");
				printk(" >\n");
#endif
			}
		} else {
			DPRINTK("RPTR points us here, but packet not done?\n");
			break;
		}
		dev_kfree_skb_irq(skb);
		priv->tx_skbs[priv->tx_read] = NULL;
		priv->tx_ring[priv->tx_read].header.raw = 0;
		priv->tx_read = (priv->tx_read+1)&(TX_RING_ENTRIES-1);
		priv->tx_count--;
	}

	/* wake up queue if it was stopped */
	if (netif_queue_stopped(dev) && !meth_tx_full(dev)) {
		netif_wake_queue(dev);
	}

	mace->eth.int_stat = METH_INT_TX_EMPTY | METH_INT_TX_PKT;
	spin_unlock(&priv->meth_lock);
}

static void meth_error(struct net_device* dev, unsigned status)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;

	printk(KERN_WARNING "meth: error status: 0x%08x\n",status);
	/* check for errors too... */
	if (status & (METH_INT_TX_LINK_FAIL))
		printk(KERN_WARNING "meth: link failure\n");
	/* Should I do full reset in this case? */
	if (status & (METH_INT_MEM_ERROR))
		printk(KERN_WARNING "meth: memory error\n");
	if (status & (METH_INT_TX_ABORT))
		printk(KERN_WARNING "meth: aborted\n");
	if (status & (METH_INT_RX_OVERFLOW))
		printk(KERN_WARNING "meth: Rx overflow\n");
	if (status & (METH_INT_RX_UNDERFLOW)) {
		printk(KERN_WARNING "meth: Rx underflow\n");
		spin_lock(&priv->meth_lock);
		mace->eth.int_stat = METH_INT_RX_UNDERFLOW;
		/* more underflow interrupts will be delivered, 
		 * effectively throwing us into an infinite loop.
		 *  Thus I stop processing Rx in this case. */
		priv->dma_ctrl &= ~METH_DMA_RX_EN;
		mace->eth.dma_ctrl = priv->dma_ctrl;
		DPRINTK("Disabled meth Rx DMA temporarily\n");
		spin_unlock(&priv->meth_lock);
	}
	mace->eth.int_stat = METH_INT_ERROR;
}

/*
 * The typical interrupt entry point
 */
static irqreturn_t meth_interrupt(int irq, void *dev_id, struct pt_regs *pregs)
{
	struct net_device *dev = (struct net_device *)dev_id;
	struct meth_private *priv = (struct meth_private *) dev->priv;
	unsigned long status;

	status = mace->eth.int_stat;
	while (status & 0xff) {
		/* First handle errors - if we get Rx underflow,
		 * Rx DMA will be disabled, and Rx handler will reenable
		 * it. I don't think it's possible to get Rx underflow,
		 * without getting Rx interrupt */
		if (status & METH_INT_ERROR) {
			meth_error(dev, status);
		}
		if (status & (METH_INT_TX_EMPTY | METH_INT_TX_PKT)) {
			/* a transmission is over: free the skb */
			meth_tx_cleanup(dev, status);
		}
		if (status & METH_INT_RX_THRESHOLD) {
			if (!(priv->dma_ctrl & METH_DMA_RX_INT_EN))
				break;
			/* send it to meth_rx for handling */
			meth_rx(dev, status);
		}
		status = mace->eth.int_stat;
	}

	return IRQ_HANDLED;
}

/*
 * Transmits packets that fit into TX descriptor (are <=120B)
 */
static void meth_tx_short_prepare(struct meth_private *priv,
				  struct sk_buff *skb)
{
	tx_packet *desc = &priv->tx_ring[priv->tx_write];
	int len = (skb->len < ETH_ZLEN) ? ETH_ZLEN : skb->len;

	desc->header.raw = METH_TX_CMD_INT_EN | (len-1) | ((128-len) << 16);
	/* maybe I should set whole thing to 0 first... */
	memcpy(desc->data.dt + (120 - len), skb->data, skb->len);
	if (skb->len < len)
		memset(desc->data.dt + 120 - len + skb->len, 0, len-skb->len);
}
#define TX_CATBUF1 BIT(25)
static void meth_tx_1page_prepare(struct meth_private *priv,
				  struct sk_buff *skb)
{
	tx_packet *desc = &priv->tx_ring[priv->tx_write];
	void *buffer_data = (void *)(((unsigned long)skb->data + 7) & ~7);
	int unaligned_len = (int)((unsigned long)buffer_data - (unsigned long)skb->data);
	int buffer_len = skb->len - unaligned_len;
	dma_addr_t catbuf;

	desc->header.raw = METH_TX_CMD_INT_EN | TX_CATBUF1 | (skb->len - 1);

	/* unaligned part */
	if (unaligned_len) {
		memcpy(desc->data.dt + (120 - unaligned_len),
		       skb->data, unaligned_len);
		desc->header.raw |= (128 - unaligned_len) << 16;
	}

	/* first page */
	catbuf = dma_map_single(NULL, buffer_data, buffer_len,
				DMA_TO_DEVICE);
	desc->data.cat_buf[0].form.start_addr = catbuf >> 3;
	desc->data.cat_buf[0].form.len = buffer_len - 1;
}
#define TX_CATBUF2 BIT(26)
static void meth_tx_2page_prepare(struct meth_private *priv,
				  struct sk_buff *skb)
{
	tx_packet *desc = &priv->tx_ring[priv->tx_write];
	void *buffer1_data = (void *)(((unsigned long)skb->data + 7) & ~7);
	void *buffer2_data = (void *)PAGE_ALIGN((unsigned long)skb->data);
	int unaligned_len = (int)((unsigned long)buffer1_data - (unsigned long)skb->data);
	int buffer1_len = (int)((unsigned long)buffer2_data - (unsigned long)buffer1_data);
	int buffer2_len = skb->len - buffer1_len - unaligned_len;
	dma_addr_t catbuf1, catbuf2;

	desc->header.raw = METH_TX_CMD_INT_EN | TX_CATBUF1 | TX_CATBUF2| (skb->len - 1);
	/* unaligned part */
	if (unaligned_len){
		memcpy(desc->data.dt + (120 - unaligned_len),
		       skb->data, unaligned_len);
		desc->header.raw |= (128 - unaligned_len) << 16;
	}

	/* first page */
	catbuf1 = dma_map_single(NULL, buffer1_data, buffer1_len,
				 DMA_TO_DEVICE);
	desc->data.cat_buf[0].form.start_addr = catbuf1 >> 3;
	desc->data.cat_buf[0].form.len = buffer1_len - 1;
	/* second page */
	catbuf2 = dma_map_single(NULL, buffer2_data, buffer2_len,
				 DMA_TO_DEVICE);
	desc->data.cat_buf[1].form.start_addr = catbuf2 >> 3;
	desc->data.cat_buf[1].form.len = buffer2_len - 1;
}

static void meth_add_to_tx_ring(struct meth_private *priv, struct sk_buff *skb)
{
	/* Remember the skb, so we can free it at interrupt time */
	priv->tx_skbs[priv->tx_write] = skb;
	if (skb->len <= 120) {
		/* Whole packet fits into descriptor */
		meth_tx_short_prepare(priv, skb);
	} else if (PAGE_ALIGN((unsigned long)skb->data) !=
		   PAGE_ALIGN((unsigned long)skb->data + skb->len - 1)) {
		/* Packet crosses page boundary */
		meth_tx_2page_prepare(priv, skb);
	} else {
		/* Packet is in one page */
		meth_tx_1page_prepare(priv, skb);
	}
	priv->tx_write = (priv->tx_write + 1) & (TX_RING_ENTRIES - 1);
	mace->eth.tx_info = priv->tx_write;
	priv->tx_count++;
}

/*
 * Transmit a packet (called by the kernel)
 */
static int meth_tx(struct sk_buff *skb, struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;
	unsigned long flags;

	spin_lock_irqsave(&priv->meth_lock, flags);
	/* Stop DMA notification */
	priv->dma_ctrl &= ~(METH_DMA_TX_INT_EN);
	mace->eth.dma_ctrl = priv->dma_ctrl;

	meth_add_to_tx_ring(priv, skb);
	dev->trans_start = jiffies; /* save the timestamp */

	/* If TX ring is full, tell the upper layer to stop sending packets */
	if (meth_tx_full(dev)) {
	        printk(KERN_DEBUG "TX full: stopping\n");
		netif_stop_queue(dev);
	}

	/* Restart DMA notification */
	priv->dma_ctrl |= METH_DMA_TX_INT_EN;
	mace->eth.dma_ctrl = priv->dma_ctrl;

	spin_unlock_irqrestore(&priv->meth_lock, flags);

	return 0;
}

/*
 * Deal with a transmit timeout.
 */
static void meth_tx_timeout(struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;
	unsigned long flags;

	printk(KERN_WARNING "%s: transmit timed out\n", dev->name);

	/* Protect against concurrent rx interrupts */
	spin_lock_irqsave(&priv->meth_lock,flags);

	/* Try to reset the interface. */
	meth_reset(dev);

	priv->stats.tx_errors++;

	/* Clear all rings */
	meth_free_tx_ring(priv);
	meth_free_rx_ring(priv);
	meth_init_tx_ring(priv);
	meth_init_rx_ring(priv);

	/* Restart dma */
	priv->dma_ctrl |= METH_DMA_TX_EN | METH_DMA_RX_EN | METH_DMA_RX_INT_EN;
	mace->eth.dma_ctrl = priv->dma_ctrl;

	/* Enable interrupt */
	spin_unlock_irqrestore(&priv->meth_lock, flags);

	dev->trans_start = jiffies;
	netif_wake_queue(dev);

	return;
}

/*
 * Ioctl commands 
 */
static int meth_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
	/* XXX Not yet implemented */
	switch(cmd) { 
	case SIOCGMIIPHY:
	case SIOCGMIIREG:
	case SIOCSMIIREG:
	default:
		return -EOPNOTSUPP;
	}
}

/*
 * Return statistics to the caller
 */
static struct net_device_stats *meth_stats(struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;
	return &priv->stats;
}

/*
 * The init function.
 */
static struct net_device *meth_init(void)
{
	struct net_device *dev;
	struct meth_private *priv;
	int ret;

	dev = alloc_etherdev(sizeof(struct meth_private));
	if (!dev)
		return ERR_PTR(-ENOMEM);

	dev->open            = meth_open;
	dev->stop            = meth_release;
	dev->hard_start_xmit = meth_tx;
	dev->do_ioctl        = meth_ioctl;
	dev->get_stats       = meth_stats;
#ifdef HAVE_TX_TIMEOUT
	dev->tx_timeout      = meth_tx_timeout;
	dev->watchdog_timeo  = timeout;
#endif
	dev->irq	     = MACE_ETHERNET_IRQ;
	dev->base_addr	     = (unsigned long)&mace->eth;

	priv = (struct meth_private *) dev->priv;
	spin_lock_init(&priv->meth_lock);

	ret = register_netdev(dev);
	if (ret) {
		free_netdev(dev);
		return ERR_PTR(ret);
	}

	printk(KERN_INFO "%s: SGI MACE Ethernet rev. %d\n",
	       dev->name, (unsigned int)(mace->eth.mac_ctrl >> 29));
	return 0;
}

static struct net_device *meth_dev;

static int __init meth_init_module(void)
{
	meth_dev = meth_init();
	if (IS_ERR(meth_dev))
		return PTR_ERR(meth_dev);
	return 0;
}

static void __exit meth_exit_module(void)
{
	unregister_netdev(meth_dev);
	free_netdev(meth_dev);
}

module_init(meth_init_module);
module_exit(meth_exit_module);