Free Electrons

Embedded Linux Experts

  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
/*
 *  Amiga Linux/m68k Ariadne Ethernet Driver
 *
 *  © Copyright 1995-2003 by Geert Uytterhoeven (geert@linux-m68k.org)
 *			     Peter De Schrijver (p2@mind.be)
 *
 *  ---------------------------------------------------------------------------
 *
 *  This program is based on
 *
 *	lance.c:	An AMD LANCE ethernet driver for linux.
 *			Written 1993-94 by Donald Becker.
 *
 *	Am79C960:	PCnet(tm)-ISA Single-Chip Ethernet Controller
 *			Advanced Micro Devices
 *			Publication #16907, Rev. B, Amendment/0, May 1994
 *
 *	MC68230:	Parallel Interface/Timer (PI/T)
 *			Motorola Semiconductors, December, 1983
 *
 *  ---------------------------------------------------------------------------
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License.  See the file COPYING in the main directory of the Linux
 *  distribution for more details.
 *
 *  ---------------------------------------------------------------------------
 *
 *  The Ariadne is a Zorro-II board made by Village Tronic. It contains:
 *
 *	- an Am79C960 PCnet-ISA Single-Chip Ethernet Controller with both
 *	  10BASE-2 (thin coax) and 10BASE-T (UTP) connectors
 *
 *	- an MC68230 Parallel Interface/Timer configured as 2 parallel ports
 */

#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/interrupt.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/zorro.h>
#include <linux/bitops.h>

#include <asm/amigaints.h>
#include <asm/amigahw.h>
#include <asm/irq.h>

#include "ariadne.h"


#ifdef ARIADNE_DEBUG
int ariadne_debug = ARIADNE_DEBUG;
#else
int ariadne_debug = 1;
#endif


    /*
     *	Macros to Fix Endianness problems
     */

				/* Swap the Bytes in a WORD */
#define swapw(x)	(((x>>8)&0x00ff)|((x<<8)&0xff00))
				/* Get the Low BYTE in a WORD */
#define lowb(x)		(x&0xff)
				/* Get the Swapped High WORD in a LONG */
#define swhighw(x)	((((x)>>8)&0xff00)|(((x)>>24)&0x00ff))
				/* Get the Swapped Low WORD in a LONG */
#define swloww(x)	((((x)<<8)&0xff00)|(((x)>>8)&0x00ff))


    /*
     *	Transmit/Receive Ring Definitions
     */

#define TX_RING_SIZE	5
#define RX_RING_SIZE	16

#define PKT_BUF_SIZE	1520


    /*
     *	Private Device Data
     */

struct ariadne_private {
    volatile struct TDRE *tx_ring[TX_RING_SIZE];
    volatile struct RDRE *rx_ring[RX_RING_SIZE];
    volatile u_short *tx_buff[TX_RING_SIZE];
    volatile u_short *rx_buff[RX_RING_SIZE];
    int cur_tx, cur_rx;			/* The next free ring entry */
    int dirty_tx;			/* The ring entries to be free()ed. */
    char tx_full;
};


    /*
     *	Structure Created in the Ariadne's RAM Buffer
     */

struct lancedata {
    struct TDRE tx_ring[TX_RING_SIZE];
    struct RDRE rx_ring[RX_RING_SIZE];
    u_short tx_buff[TX_RING_SIZE][PKT_BUF_SIZE/sizeof(u_short)];
    u_short rx_buff[RX_RING_SIZE][PKT_BUF_SIZE/sizeof(u_short)];
};

static int ariadne_open(struct net_device *dev);
static void ariadne_init_ring(struct net_device *dev);
static netdev_tx_t ariadne_start_xmit(struct sk_buff *skb,
				      struct net_device *dev);
static void ariadne_tx_timeout(struct net_device *dev);
static int ariadne_rx(struct net_device *dev);
static void ariadne_reset(struct net_device *dev);
static irqreturn_t ariadne_interrupt(int irq, void *data);
static int ariadne_close(struct net_device *dev);
static struct net_device_stats *ariadne_get_stats(struct net_device *dev);
static void set_multicast_list(struct net_device *dev);


static void memcpyw(volatile u_short *dest, u_short *src, int len)
{
    while (len >= 2) {
	*(dest++) = *(src++);
	len -= 2;
    }
    if (len == 1)
	*dest = (*(u_char *)src)<<8;
}


static int __devinit ariadne_init_one(struct zorro_dev *z,
				      const struct zorro_device_id *ent);
static void __devexit ariadne_remove_one(struct zorro_dev *z);


static struct zorro_device_id ariadne_zorro_tbl[] __devinitdata = {
    { ZORRO_PROD_VILLAGE_TRONIC_ARIADNE },
    { 0 }
};
MODULE_DEVICE_TABLE(zorro, ariadne_zorro_tbl);

static struct zorro_driver ariadne_driver = {
    .name	= "ariadne",
    .id_table	= ariadne_zorro_tbl,
    .probe	= ariadne_init_one,
    .remove	= __devexit_p(ariadne_remove_one),
};

static const struct net_device_ops ariadne_netdev_ops = {
	.ndo_open		= ariadne_open,
	.ndo_stop		= ariadne_close,
	.ndo_start_xmit		= ariadne_start_xmit,
	.ndo_tx_timeout		= ariadne_tx_timeout,
	.ndo_get_stats		= ariadne_get_stats,
	.ndo_set_multicast_list	= set_multicast_list,
	.ndo_validate_addr	= eth_validate_addr,
	.ndo_change_mtu		= eth_change_mtu,
	.ndo_set_mac_address	= eth_mac_addr,
};

static int __devinit ariadne_init_one(struct zorro_dev *z,
				      const struct zorro_device_id *ent)
{
    unsigned long board = z->resource.start;
    unsigned long base_addr = board+ARIADNE_LANCE;
    unsigned long mem_start = board+ARIADNE_RAM;
    struct resource *r1, *r2;
    struct net_device *dev;
    struct ariadne_private *priv;
    int err;

    r1 = request_mem_region(base_addr, sizeof(struct Am79C960), "Am79C960");
    if (!r1)
	return -EBUSY;
    r2 = request_mem_region(mem_start, ARIADNE_RAM_SIZE, "RAM");
    if (!r2) {
	release_resource(r1);
	return -EBUSY;
    }

    dev = alloc_etherdev(sizeof(struct ariadne_private));
    if (dev == NULL) {
	release_resource(r1);
	release_resource(r2);
	return -ENOMEM;
    }

    priv = netdev_priv(dev);

    r1->name = dev->name;
    r2->name = dev->name;

    dev->dev_addr[0] = 0x00;
    dev->dev_addr[1] = 0x60;
    dev->dev_addr[2] = 0x30;
    dev->dev_addr[3] = (z->rom.er_SerialNumber>>16) & 0xff;
    dev->dev_addr[4] = (z->rom.er_SerialNumber>>8) & 0xff;
    dev->dev_addr[5] = z->rom.er_SerialNumber & 0xff;
    dev->base_addr = ZTWO_VADDR(base_addr);
    dev->mem_start = ZTWO_VADDR(mem_start);
    dev->mem_end = dev->mem_start+ARIADNE_RAM_SIZE;

    dev->netdev_ops = &ariadne_netdev_ops;
    dev->watchdog_timeo = 5*HZ;

    err = register_netdev(dev);
    if (err) {
	release_resource(r1);
	release_resource(r2);
	free_netdev(dev);
	return err;
    }
    zorro_set_drvdata(z, dev);

    printk(KERN_INFO "%s: Ariadne at 0x%08lx, Ethernet Address %pM\n",
           dev->name, board, dev->dev_addr);

    return 0;
}


static int ariadne_open(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;
    u_short in;
    u_long version;
    int i;

    /* Reset the LANCE */
    in = lance->Reset;

    /* Stop the LANCE */
    lance->RAP = CSR0;		/* PCnet-ISA Controller Status */
    lance->RDP = STOP;

    /* Check the LANCE version */
    lance->RAP = CSR88;		/* Chip ID */
    version = swapw(lance->RDP);
    lance->RAP = CSR89;		/* Chip ID */
    version |= swapw(lance->RDP)<<16;
    if ((version & 0x00000fff) != 0x00000003) {
	printk(KERN_WARNING "ariadne_open: Couldn't find AMD Ethernet Chip\n");
	return -EAGAIN;
    }
    if ((version & 0x0ffff000) != 0x00003000) {
	printk(KERN_WARNING "ariadne_open: Couldn't find Am79C960 (Wrong part "
	       "number = %ld)\n", (version & 0x0ffff000)>>12);
	return -EAGAIN;
    }
#if 0
    printk(KERN_DEBUG "ariadne_open: Am79C960 (PCnet-ISA) Revision %ld\n",
	   (version & 0xf0000000)>>28);
#endif

    ariadne_init_ring(dev);

    /* Miscellaneous Stuff */
    lance->RAP = CSR3;		/* Interrupt Masks and Deferral Control */
    lance->RDP = 0x0000;
    lance->RAP = CSR4;		/* Test and Features Control */
    lance->RDP = DPOLL|APAD_XMT|MFCOM|RCVCCOM|TXSTRTM|JABM;

    /* Set the Multicast Table */
    lance->RAP = CSR8;		/* Logical Address Filter, LADRF[15:0] */
    lance->RDP = 0x0000;
    lance->RAP = CSR9;		/* Logical Address Filter, LADRF[31:16] */
    lance->RDP = 0x0000;
    lance->RAP = CSR10;		/* Logical Address Filter, LADRF[47:32] */
    lance->RDP = 0x0000;
    lance->RAP = CSR11;		/* Logical Address Filter, LADRF[63:48] */
    lance->RDP = 0x0000;

    /* Set the Ethernet Hardware Address */
    lance->RAP = CSR12;		/* Physical Address Register, PADR[15:0] */
    lance->RDP = ((u_short *)&dev->dev_addr[0])[0];
    lance->RAP = CSR13;		/* Physical Address Register, PADR[31:16] */
    lance->RDP = ((u_short *)&dev->dev_addr[0])[1];
    lance->RAP = CSR14;		/* Physical Address Register, PADR[47:32] */
    lance->RDP = ((u_short *)&dev->dev_addr[0])[2];

    /* Set the Init Block Mode */
    lance->RAP = CSR15;		/* Mode Register */
    lance->RDP = 0x0000;

    /* Set the Transmit Descriptor Ring Pointer */
    lance->RAP = CSR30;		/* Base Address of Transmit Ring */
    lance->RDP = swloww(ARIADNE_RAM+offsetof(struct lancedata, tx_ring));
    lance->RAP = CSR31;		/* Base Address of transmit Ring */
    lance->RDP = swhighw(ARIADNE_RAM+offsetof(struct lancedata, tx_ring));

    /* Set the Receive Descriptor Ring Pointer */
    lance->RAP = CSR24;		/* Base Address of Receive Ring */
    lance->RDP = swloww(ARIADNE_RAM+offsetof(struct lancedata, rx_ring));
    lance->RAP = CSR25;		/* Base Address of Receive Ring */
    lance->RDP = swhighw(ARIADNE_RAM+offsetof(struct lancedata, rx_ring));

    /* Set the Number of RX and TX Ring Entries */
    lance->RAP = CSR76;		/* Receive Ring Length */
    lance->RDP = swapw(((u_short)-RX_RING_SIZE));
    lance->RAP = CSR78;		/* Transmit Ring Length */
    lance->RDP = swapw(((u_short)-TX_RING_SIZE));

    /* Enable Media Interface Port Auto Select (10BASE-2/10BASE-T) */
    lance->RAP = ISACSR2;	/* Miscellaneous Configuration */
    lance->IDP = ASEL;

    /* LED Control */
    lance->RAP = ISACSR5;	/* LED1 Status */
    lance->IDP = PSE|XMTE;
    lance->RAP = ISACSR6;	/* LED2 Status */
    lance->IDP = PSE|COLE;
    lance->RAP = ISACSR7;	/* LED3 Status */
    lance->IDP = PSE|RCVE;

    netif_start_queue(dev);

    i = request_irq(IRQ_AMIGA_PORTS, ariadne_interrupt, IRQF_SHARED,
                    dev->name, dev);
    if (i) return i;

    lance->RAP = CSR0;		/* PCnet-ISA Controller Status */
    lance->RDP = INEA|STRT;

    return 0;
}


static void ariadne_init_ring(struct net_device *dev)
{
    struct ariadne_private *priv = netdev_priv(dev);
    volatile struct lancedata *lancedata = (struct lancedata *)dev->mem_start;
    int i;

    netif_stop_queue(dev);

    priv->tx_full = 0;
    priv->cur_rx = priv->cur_tx = 0;
    priv->dirty_tx = 0;

    /* Set up TX Ring */
    for (i = 0; i < TX_RING_SIZE; i++) {
	volatile struct TDRE *t = &lancedata->tx_ring[i];
	t->TMD0 = swloww(ARIADNE_RAM+offsetof(struct lancedata, tx_buff[i]));
	t->TMD1 = swhighw(ARIADNE_RAM+offsetof(struct lancedata, tx_buff[i])) |
		  TF_STP | TF_ENP;
	t->TMD2 = swapw((u_short)-PKT_BUF_SIZE);
	t->TMD3 = 0;
	priv->tx_ring[i] = &lancedata->tx_ring[i];
	priv->tx_buff[i] = lancedata->tx_buff[i];
#if 0
	printk(KERN_DEBUG "TX Entry %2d at %p, Buf at %p\n", i,
	       &lancedata->tx_ring[i], lancedata->tx_buff[i]);
#endif
    }

    /* Set up RX Ring */
    for (i = 0; i < RX_RING_SIZE; i++) {
	volatile struct RDRE *r = &lancedata->rx_ring[i];
	r->RMD0 = swloww(ARIADNE_RAM+offsetof(struct lancedata, rx_buff[i]));
	r->RMD1 = swhighw(ARIADNE_RAM+offsetof(struct lancedata, rx_buff[i])) |
		  RF_OWN;
	r->RMD2 = swapw((u_short)-PKT_BUF_SIZE);
	r->RMD3 = 0x0000;
	priv->rx_ring[i] = &lancedata->rx_ring[i];
	priv->rx_buff[i] = lancedata->rx_buff[i];
#if 0
	printk(KERN_DEBUG "RX Entry %2d at %p, Buf at %p\n", i,
	       &lancedata->rx_ring[i], lancedata->rx_buff[i]);
#endif
    }
}


static int ariadne_close(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;

    netif_stop_queue(dev);

    lance->RAP = CSR112;	/* Missed Frame Count */
    dev->stats.rx_missed_errors = swapw(lance->RDP);
    lance->RAP = CSR0;		/* PCnet-ISA Controller Status */

    if (ariadne_debug > 1) {
	printk(KERN_DEBUG "%s: Shutting down ethercard, status was %2.2x.\n",
	       dev->name, lance->RDP);
	printk(KERN_DEBUG "%s: %lu packets missed\n", dev->name,
	       dev->stats.rx_missed_errors);
    }

    /* We stop the LANCE here -- it occasionally polls memory if we don't. */
    lance->RDP = STOP;

    free_irq(IRQ_AMIGA_PORTS, dev);

    return 0;
}


static inline void ariadne_reset(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;

    lance->RAP = CSR0;	/* PCnet-ISA Controller Status */
    lance->RDP = STOP;
    ariadne_init_ring(dev);
    lance->RDP = INEA|STRT;
    netif_start_queue(dev);
}


static irqreturn_t ariadne_interrupt(int irq, void *data)
{
    struct net_device *dev = (struct net_device *)data;
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;
    struct ariadne_private *priv;
    int csr0, boguscnt;
    int handled = 0;

    lance->RAP = CSR0;			/* PCnet-ISA Controller Status */

    if (!(lance->RDP & INTR))		/* Check if any interrupt has been */
	return IRQ_NONE;		/* generated by the board. */

    priv = netdev_priv(dev);

    boguscnt = 10;
    while ((csr0 = lance->RDP) & (ERR|RINT|TINT) && --boguscnt >= 0) {
	/* Acknowledge all of the current interrupt sources ASAP. */
	lance->RDP = csr0 & ~(INEA|TDMD|STOP|STRT|INIT);

#if 0
	if (ariadne_debug > 5) {
	    printk(KERN_DEBUG "%s: interrupt  csr0=%#2.2x new csr=%#2.2x.",
		   dev->name, csr0, lance->RDP);
	    printk("[");
	    if (csr0 & INTR)
		printk(" INTR");
	    if (csr0 & INEA)
		printk(" INEA");
	    if (csr0 & RXON)
		printk(" RXON");
	    if (csr0 & TXON)
		printk(" TXON");
	    if (csr0 & TDMD)
		printk(" TDMD");
	    if (csr0 & STOP)
		printk(" STOP");
	    if (csr0 & STRT)
		printk(" STRT");
	    if (csr0 & INIT)
		printk(" INIT");
	    if (csr0 & ERR)
		printk(" ERR");
	    if (csr0 & BABL)
		printk(" BABL");
	    if (csr0 & CERR)
		printk(" CERR");
	    if (csr0 & MISS)
		printk(" MISS");
	    if (csr0 & MERR)
		printk(" MERR");
	    if (csr0 & RINT)
		printk(" RINT");
	    if (csr0 & TINT)
		printk(" TINT");
	    if (csr0 & IDON)
		printk(" IDON");
	    printk(" ]\n");
	}
#endif

	if (csr0 & RINT) {	/* Rx interrupt */
	    handled = 1;
	    ariadne_rx(dev);
	}

	if (csr0 & TINT) {	/* Tx-done interrupt */
	    int dirty_tx = priv->dirty_tx;

	    handled = 1;
	    while (dirty_tx < priv->cur_tx) {
		int entry = dirty_tx % TX_RING_SIZE;
		int status = lowb(priv->tx_ring[entry]->TMD1);

		if (status & TF_OWN)
		    break;	/* It still hasn't been Txed */

		priv->tx_ring[entry]->TMD1 &= 0xff00;

		if (status & TF_ERR) {
		    /* There was an major error, log it. */
		    int err_status = priv->tx_ring[entry]->TMD3;
		    dev->stats.tx_errors++;
		    if (err_status & EF_RTRY)
			dev->stats.tx_aborted_errors++;
		    if (err_status & EF_LCAR)
			dev->stats.tx_carrier_errors++;
		    if (err_status & EF_LCOL)
			dev->stats.tx_window_errors++;
		    if (err_status & EF_UFLO) {
			/* Ackk!  On FIFO errors the Tx unit is turned off! */
			dev->stats.tx_fifo_errors++;
			/* Remove this verbosity later! */
			printk(KERN_ERR "%s: Tx FIFO error! Status %4.4x.\n",
			       dev->name, csr0);
			/* Restart the chip. */
			lance->RDP = STRT;
		    }
		} else {
		    if (status & (TF_MORE|TF_ONE))
			dev->stats.collisions++;
		    dev->stats.tx_packets++;
		}
		dirty_tx++;
	    }

#ifndef final_version
	    if (priv->cur_tx - dirty_tx >= TX_RING_SIZE) {
		printk(KERN_ERR "out-of-sync dirty pointer, %d vs. %d, "
		       "full=%d.\n", dirty_tx, priv->cur_tx, priv->tx_full);
		dirty_tx += TX_RING_SIZE;
	    }
#endif

	    if (priv->tx_full && netif_queue_stopped(dev) &&
		dirty_tx > priv->cur_tx - TX_RING_SIZE + 2) {
		/* The ring is no longer full. */
		priv->tx_full = 0;
		netif_wake_queue(dev);
	    }

	    priv->dirty_tx = dirty_tx;
	}

	/* Log misc errors. */
	if (csr0 & BABL) {
	    handled = 1;
	    dev->stats.tx_errors++;	/* Tx babble. */
	}
	if (csr0 & MISS) {
	    handled = 1;
	    dev->stats.rx_errors++;	/* Missed a Rx frame. */
	}
	if (csr0 & MERR) {
	    handled = 1;
	    printk(KERN_ERR "%s: Bus master arbitration failure, status "
		   "%4.4x.\n", dev->name, csr0);
	    /* Restart the chip. */
	    lance->RDP = STRT;
	}
    }

    /* Clear any other interrupt, and set interrupt enable. */
    lance->RAP = CSR0;		/* PCnet-ISA Controller Status */
    lance->RDP = INEA|BABL|CERR|MISS|MERR|IDON;

#if 0
    if (ariadne_debug > 4)
	printk(KERN_DEBUG "%s: exiting interrupt, csr%d=%#4.4x.\n", dev->name,
	       lance->RAP, lance->RDP);
#endif
    return IRQ_RETVAL(handled);
}


static void ariadne_tx_timeout(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;

    printk(KERN_ERR "%s: transmit timed out, status %4.4x, resetting.\n",
	   dev->name, lance->RDP);
    ariadne_reset(dev);
    netif_wake_queue(dev);
}


static netdev_tx_t ariadne_start_xmit(struct sk_buff *skb,
				      struct net_device *dev)
{
    struct ariadne_private *priv = netdev_priv(dev);
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;
    int entry;
    unsigned long flags;
    int len = skb->len;

#if 0
    if (ariadne_debug > 3) {
	lance->RAP = CSR0;	/* PCnet-ISA Controller Status */
	printk(KERN_DEBUG "%s: ariadne_start_xmit() called, csr0 %4.4x.\n",
	       dev->name, lance->RDP);
	lance->RDP = 0x0000;
    }
#endif

    /* FIXME: is the 79C960 new enough to do its own padding right ? */
    if (skb->len < ETH_ZLEN)
    {
    	if (skb_padto(skb, ETH_ZLEN))
    	    return NETDEV_TX_OK;
    	len = ETH_ZLEN;
    }

    /* Fill in a Tx ring entry */

#if 0
{
    printk(KERN_DEBUG "TX pkt type 0x%04x from %pM to %pM "
	   " data 0x%08x len %d\n",
	   ((u_short *)skb->data)[6],
	   skb->data + 6, skb->data,
	   (int)skb->data, (int)skb->len);
}
#endif

    local_irq_save(flags);

    entry = priv->cur_tx % TX_RING_SIZE;

    /* Caution: the write order is important here, set the base address with
		the "ownership" bits last. */

    priv->tx_ring[entry]->TMD2 = swapw((u_short)-skb->len);
    priv->tx_ring[entry]->TMD3 = 0x0000;
    memcpyw(priv->tx_buff[entry], (u_short *)skb->data, len);

#if 0
    {
	int i, len;

	len = skb->len > 64 ? 64 : skb->len;
	len >>= 1;
	for (i = 0; i < len; i += 8) {
	    int j;
	    printk(KERN_DEBUG "%04x:", i);
	    for (j = 0; (j < 8) && ((i+j) < len); j++) {
		if (!(j & 1))
		    printk(" ");
		printk("%04x", priv->tx_buff[entry][i+j]);
	    }
	    printk("\n");
	}
    }
#endif

    priv->tx_ring[entry]->TMD1 = (priv->tx_ring[entry]->TMD1&0xff00)|TF_OWN|TF_STP|TF_ENP;

    dev_kfree_skb(skb);

    priv->cur_tx++;
    if ((priv->cur_tx >= TX_RING_SIZE) && (priv->dirty_tx >= TX_RING_SIZE)) {

#if 0
	printk(KERN_DEBUG "*** Subtracting TX_RING_SIZE from cur_tx (%d) and "
	       "dirty_tx (%d)\n", priv->cur_tx, priv->dirty_tx);
#endif

	priv->cur_tx -= TX_RING_SIZE;
	priv->dirty_tx -= TX_RING_SIZE;
    }
    dev->stats.tx_bytes += len;

    /* Trigger an immediate send poll. */
    lance->RAP = CSR0;		/* PCnet-ISA Controller Status */
    lance->RDP = INEA|TDMD;

    if (lowb(priv->tx_ring[(entry+1) % TX_RING_SIZE]->TMD1) != 0) {
	netif_stop_queue(dev);
	priv->tx_full = 1;
    }
    local_irq_restore(flags);

    return NETDEV_TX_OK;
}


static int ariadne_rx(struct net_device *dev)
{
    struct ariadne_private *priv = netdev_priv(dev);
    int entry = priv->cur_rx % RX_RING_SIZE;
    int i;

    /* If we own the next entry, it's a new packet. Send it up. */
    while (!(lowb(priv->rx_ring[entry]->RMD1) & RF_OWN)) {
	int status = lowb(priv->rx_ring[entry]->RMD1);

	if (status != (RF_STP|RF_ENP)) {	/* There was an error. */
	    /* There is a tricky error noted by John Murphy,
		<murf@perftech.com> to Russ Nelson: Even with full-sized
		buffers it's possible for a jabber packet to use two
		buffers, with only the last correctly noting the error. */
	    if (status & RF_ENP)
		/* Only count a general error at the end of a packet.*/
		dev->stats.rx_errors++;
	    if (status & RF_FRAM)
		dev->stats.rx_frame_errors++;
	    if (status & RF_OFLO)
		dev->stats.rx_over_errors++;
	    if (status & RF_CRC)
		dev->stats.rx_crc_errors++;
	    if (status & RF_BUFF)
		dev->stats.rx_fifo_errors++;
	    priv->rx_ring[entry]->RMD1 &= 0xff00|RF_STP|RF_ENP;
	} else {
	    /* Malloc up new buffer, compatible with net-3. */
	    short pkt_len = swapw(priv->rx_ring[entry]->RMD3);
	    struct sk_buff *skb;

	    skb = dev_alloc_skb(pkt_len+2);
	    if (skb == NULL) {
		printk(KERN_WARNING "%s: Memory squeeze, deferring packet.\n",
		       dev->name);
		for (i = 0; i < RX_RING_SIZE; i++)
		    if (lowb(priv->rx_ring[(entry+i) % RX_RING_SIZE]->RMD1) & RF_OWN)
			break;

		if (i > RX_RING_SIZE-2) {
		    dev->stats.rx_dropped++;
		    priv->rx_ring[entry]->RMD1 |= RF_OWN;
		    priv->cur_rx++;
		}
		break;
	    }


	    skb_reserve(skb,2);		/* 16 byte align */
	    skb_put(skb,pkt_len);	/* Make room */
	    skb_copy_to_linear_data(skb, (char *)priv->rx_buff[entry], pkt_len);
	    skb->protocol=eth_type_trans(skb,dev);
#if 0
{
	    printk(KERN_DEBUG "RX pkt type 0x%04x from ",
		   ((u_short *)skb->data)[6]);
	    {
		u_char *ptr = &((u_char *)skb->data)[6];
		printk("%pM", ptr);
	    }
	    printk(" to ");
	    {
		u_char *ptr = (u_char *)skb->data;
		printk("%pM", ptr);
	    }
	    printk(" data 0x%08x len %d\n", (int)skb->data, (int)skb->len);
}
#endif

	    netif_rx(skb);
	    dev->stats.rx_packets++;
	    dev->stats.rx_bytes += pkt_len;
	}

	priv->rx_ring[entry]->RMD1 |= RF_OWN;
	entry = (++priv->cur_rx) % RX_RING_SIZE;
    }

    priv->cur_rx = priv->cur_rx % RX_RING_SIZE;

    /* We should check that at least two ring entries are free.	 If not,
       we should free one and mark stats->rx_dropped++. */

    return 0;
}


static struct net_device_stats *ariadne_get_stats(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;
    short saved_addr;
    unsigned long flags;

    local_irq_save(flags);
    saved_addr = lance->RAP;
    lance->RAP = CSR112;		/* Missed Frame Count */
    dev->stats.rx_missed_errors = swapw(lance->RDP);
    lance->RAP = saved_addr;
    local_irq_restore(flags);

    return &dev->stats;
}


/* Set or clear the multicast filter for this adaptor.
    num_addrs == -1	Promiscuous mode, receive all packets
    num_addrs == 0	Normal mode, clear multicast list
    num_addrs > 0	Multicast mode, receive normal and MC packets, and do
			best-effort filtering.
 */
static void set_multicast_list(struct net_device *dev)
{
    volatile struct Am79C960 *lance = (struct Am79C960*)dev->base_addr;

    if (!netif_running(dev))
	return;

    netif_stop_queue(dev);

    /* We take the simple way out and always enable promiscuous mode. */
    lance->RAP = CSR0;			/* PCnet-ISA Controller Status */
    lance->RDP = STOP;			/* Temporarily stop the lance. */
    ariadne_init_ring(dev);

    if (dev->flags & IFF_PROMISC) {
	lance->RAP = CSR15;		/* Mode Register */
	lance->RDP = PROM;		/* Set promiscuous mode */
    } else {
	short multicast_table[4];
	int num_addrs = netdev_mc_count(dev);
	int i;
	/* We don't use the multicast table, but rely on upper-layer filtering. */
	memset(multicast_table, (num_addrs == 0) ? 0 : -1,
	       sizeof(multicast_table));
	for (i = 0; i < 4; i++) {
	    lance->RAP = CSR8+(i<<8);	/* Logical Address Filter */
	    lance->RDP = swapw(multicast_table[i]);
	}
	lance->RAP = CSR15;		/* Mode Register */
	lance->RDP = 0x0000;		/* Unset promiscuous mode */
    }

    lance->RAP = CSR0;			/* PCnet-ISA Controller Status */
    lance->RDP = INEA|STRT|IDON;	/* Resume normal operation. */

    netif_wake_queue(dev);
}


static void __devexit ariadne_remove_one(struct zorro_dev *z)
{
    struct net_device *dev = zorro_get_drvdata(z);

    unregister_netdev(dev);
    release_mem_region(ZTWO_PADDR(dev->base_addr), sizeof(struct Am79C960));
    release_mem_region(ZTWO_PADDR(dev->mem_start), ARIADNE_RAM_SIZE);
    free_netdev(dev);
}

static int __init ariadne_init_module(void)
{
    return zorro_register_driver(&ariadne_driver);
}

static void __exit ariadne_cleanup_module(void)
{
    zorro_unregister_driver(&ariadne_driver);
}

module_init(ariadne_init_module);
module_exit(ariadne_cleanup_module);

MODULE_LICENSE("GPL");