aboutsummaryrefslogtreecommitdiff
path: root/drivers/net/3c507.c
blob: 9e95afa49fbe26b546dd75b35a239e4a0e3fbb45 (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
/* 3c507.c: An EtherLink16 device driver for Linux. */
/*
	Written 1993,1994 by Donald Becker.

	Copyright 1993 United States Government as represented by the
	Director, National Security Agency.

	This software may be used and distributed according to the terms
	of the GNU General Public License, incorporated herein by reference.

	The author may be reached as becker@scyld.com, or C/O
	Scyld Computing Corporation
	410 Severn Ave., Suite 210
	Annapolis MD 21403


	Thanks go to jennings@Montrouge.SMR.slb.com ( Patrick Jennings)
	and jrs@world.std.com (Rick Sladkey) for testing and bugfixes.
	Mark Salazar <leslie@access.digex.net> made the changes for cards with
	only 16K packet buffers.

	Things remaining to do:
	Verify that the tx and rx buffers don't have fencepost errors.
	Move the theory of operation and memory map documentation.
	The statistics need to be updated correctly.
*/

#define DRV_NAME		"3c507"
#define DRV_VERSION		"1.10a"
#define DRV_RELDATE		"11/17/2001"

static const char version[] =
	DRV_NAME ".c:v" DRV_VERSION " " DRV_RELDATE " Donald Becker (becker@scyld.com)\n";

/*
  Sources:
	This driver wouldn't have been written with the availability of the
	Crynwr driver source code.	It provided a known-working implementation
	that filled in the gaping holes of the Intel documentation.  Three cheers
	for Russ Nelson.

	Intel Microcommunications Databook, Vol. 1, 1990.  It provides just enough
	info that the casual reader might think that it documents the i82586 :-<.
*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/string.h>
#include <linux/spinlock.h>
#include <linux/ethtool.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/bitops.h>

#include <asm/dma.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/uaccess.h>

/* use 0 for production, 1 for verification, 2..7 for debug */
#ifndef NET_DEBUG
#define NET_DEBUG 1
#endif
static unsigned int net_debug = NET_DEBUG;
#define debug net_debug


/*
  			Details of the i82586.

   You'll really need the databook to understand the details of this part,
   but the outline is that the i82586 has two separate processing units.
   Both are started from a list of three configuration tables, of which only
   the last, the System Control Block (SCB), is used after reset-time.  The SCB
   has the following fields:
		Status word
		Command word
		Tx/Command block addr.
		Rx block addr.
   The command word accepts the following controls for the Tx and Rx units:
  */

#define	 CUC_START	 0x0100
#define	 CUC_RESUME	 0x0200
#define	 CUC_SUSPEND 0x0300
#define	 RX_START	 0x0010
#define	 RX_RESUME	 0x0020
#define	 RX_SUSPEND	 0x0030

/* The Rx unit uses a list of frame descriptors and a list of data buffer
   descriptors.  We use full-sized (1518 byte) data buffers, so there is
   a one-to-one pairing of frame descriptors to buffer descriptors.

   The Tx ("command") unit executes a list of commands that look like:
		Status word		Written by the 82586 when the command is done.
		Command word	Command in lower 3 bits, post-command action in upper 3
		Link word		The address of the next command.
		Parameters		(as needed).

	Some definitions related to the Command Word are:
 */
#define CMD_EOL		0x8000			/* The last command of the list, stop. */
#define CMD_SUSP	0x4000			/* Suspend after doing cmd. */
#define CMD_INTR	0x2000			/* Interrupt after doing cmd. */

enum commands {
	CmdNOp = 0, CmdSASetup = 1, CmdConfigure = 2, CmdMulticastList = 3,
	CmdTx = 4, CmdTDR = 5, CmdDump = 6, CmdDiagnose = 7};

/* Information that need to be kept for each board. */
struct net_local {
	int last_restart;
	ushort rx_head;
	ushort rx_tail;
	ushort tx_head;
	ushort tx_cmd_link;
	ushort tx_reap;
	ushort tx_pkts_in_ring;
	spinlock_t lock;
	void __iomem *base;
};

/*
  		Details of the EtherLink16 Implementation
  The 3c507 is a generic shared-memory i82586 implementation.
  The host can map 16K, 32K, 48K, or 64K of the 64K memory into
  0x0[CD][08]0000, or all 64K into 0xF[02468]0000.
  */

/* Offsets from the base I/O address. */
#define	SA_DATA		0	/* Station address data, or 3Com signature. */
#define MISC_CTRL	6	/* Switch the SA_DATA banks, and bus config bits. */
#define RESET_IRQ	10	/* Reset the latched IRQ line. */
#define SIGNAL_CA	11	/* Frob the 82586 Channel Attention line. */
#define ROM_CONFIG	13
#define MEM_CONFIG	14
#define IRQ_CONFIG	15
#define EL16_IO_EXTENT 16

/* The ID port is used at boot-time to locate the ethercard. */
#define ID_PORT		0x100

/* Offsets to registers in the mailbox (SCB). */
#define iSCB_STATUS	0x8
#define iSCB_CMD		0xA
#define iSCB_CBL		0xC	/* Command BLock offset. */
#define iSCB_RFA		0xE	/* Rx Frame Area offset. */

/*  Since the 3c507 maps the shared memory window so that the last byte is
	at 82586 address FFFF, the first byte is at 82586 address 0, 16K, 32K, or
	48K corresponding to window sizes of 64K, 48K, 32K and 16K respectively.
	We can account for this be setting the 'SBC Base' entry in the ISCP table
	below for all the 16 bit offset addresses, and also adding the 'SCB Base'
	value to all 24 bit physical addresses (in the SCP table and the TX and RX
	Buffer Descriptors).
					-Mark
	*/
#define SCB_BASE		((unsigned)64*1024 - (dev->mem_end - dev->mem_start))

/*
  What follows in 'init_words[]' is the "program" that is downloaded to the
  82586 memory.	 It's mostly tables and command blocks, and starts at the
  reset address 0xfffff6.  This is designed to be similar to the EtherExpress,
  thus the unusual location of the SCB at 0x0008.

  Even with the additional "don't care" values, doing it this way takes less
  program space than initializing the individual tables, and I feel it's much
  cleaner.

  The databook is particularly useless for the first two structures, I had
  to use the Crynwr driver as an example.

   The memory setup is as follows:
   */

#define CONFIG_CMD	0x0018
#define SET_SA_CMD	0x0024
#define SA_OFFSET	0x002A
#define IDLELOOP	0x30
#define TDR_CMD		0x38
#define TDR_TIME	0x3C
#define DUMP_CMD	0x40
#define DIAG_CMD	0x48
#define SET_MC_CMD	0x4E
#define DUMP_DATA	0x56	/* A 170 byte buffer for dump and Set-MC into. */

#define TX_BUF_START	0x0100
#define NUM_TX_BUFS 	5
#define TX_BUF_SIZE 	(1518+14+20+16) /* packet+header+TBD */

#define RX_BUF_START	0x2000
#define RX_BUF_SIZE 	(1518+14+18)	/* packet+header+RBD */
#define RX_BUF_END		(dev->mem_end - dev->mem_start)

#define TX_TIMEOUT 5

/*
  That's it: only 86 bytes to set up the beast, including every extra
  command available.  The 170 byte buffer at DUMP_DATA is shared between the
  Dump command (called only by the diagnostic program) and the SetMulticastList
  command.

  To complete the memory setup you only have to write the station address at
  SA_OFFSET and create the Tx & Rx buffer lists.

  The Tx command chain and buffer list is setup as follows:
  A Tx command table, with the data buffer pointing to...
  A Tx data buffer descriptor.  The packet is in a single buffer, rather than
	chaining together several smaller buffers.
  A NoOp command, which initially points to itself,
  And the packet data.

  A transmit is done by filling in the Tx command table and data buffer,
  re-writing the NoOp command, and finally changing the offset of the last
  command to point to the current Tx command.  When the Tx command is finished,
  it jumps to the NoOp, when it loops until the next Tx command changes the
  "link offset" in the NoOp.  This way the 82586 never has to go through the
  slow restart sequence.

  The Rx buffer list is set up in the obvious ring structure.  We have enough
  memory (and low enough interrupt latency) that we can avoid the complicated
  Rx buffer linked lists by alway associating a full-size Rx data buffer with
  each Rx data frame.

  I current use four transmit buffers starting at TX_BUF_START (0x0100), and
  use the rest of memory, from RX_BUF_START to RX_BUF_END, for Rx buffers.

  */

static unsigned short init_words[] = {
	/*	System Configuration Pointer (SCP). */
	0x0000,					/* Set bus size to 16 bits. */
	0,0,					/* pad words. */
	0x0000,0x0000,			/* ISCP phys addr, set in init_82586_mem(). */

	/*	Intermediate System Configuration Pointer (ISCP). */
	0x0001,					/* Status word that's cleared when init is done. */
	0x0008,0,0,				/* SCB offset, (skip, skip) */

	/* System Control Block (SCB). */
	0,0xf000|RX_START|CUC_START,	/* SCB status and cmd. */
	CONFIG_CMD,				/* Command list pointer, points to Configure. */
	RX_BUF_START,				/* Rx block list. */
	0,0,0,0,				/* Error count: CRC, align, buffer, overrun. */

	/* 0x0018: Configure command.  Change to put MAC data with packet. */
	0, CmdConfigure,		/* Status, command.		*/
	SET_SA_CMD,				/* Next command is Set Station Addr. */
	0x0804,					/* "4" bytes of config data, 8 byte FIFO. */
	0x2e40,					/* Magic values, including MAC data location. */
	0,						/* Unused pad word. */

	/* 0x0024: Setup station address command. */
	0, CmdSASetup,
	SET_MC_CMD,				/* Next command. */
	0xaa00,0xb000,0x0bad,	/* Station address (to be filled in) */

	/* 0x0030: NOP, looping back to itself.	 Point to first Tx buffer to Tx. */
	0, CmdNOp, IDLELOOP, 0 /* pad */,

	/* 0x0038: A unused Time-Domain Reflectometer command. */
	0, CmdTDR, IDLELOOP, 0,

	/* 0x0040: An unused Dump State command. */
	0, CmdDump, IDLELOOP, DUMP_DATA,

	/* 0x0048: An unused Diagnose command. */
	0, CmdDiagnose, IDLELOOP,

	/* 0x004E: An empty set-multicast-list command. */
	0, CmdMulticastList, IDLELOOP, 0,
};

/* Index to functions, as function prototypes. */

static int	el16_probe1(struct net_device *dev, int ioaddr);
static int	el16_open(struct net_device *dev);
static netdev_tx_t el16_send_packet(struct sk_buff *skb,
				    struct net_device *dev);
static irqreturn_t el16_interrupt(int irq, void *dev_id);
static void el16_rx(struct net_device *dev);
static int	el16_close(struct net_device *dev);
static void el16_tx_timeout (struct net_device *dev);

static void hardware_send_packet(struct net_device *dev, void *buf, short length, short pad);
static void init_82586_mem(struct net_device *dev);
static const struct ethtool_ops netdev_ethtool_ops;
static void init_rx_bufs(struct net_device *);

static int io = 0x300;
static int irq;
static int mem_start;


/* Check for a network adaptor of this type, and return '0' iff one exists.
	If dev->base_addr == 0, probe all likely locations.
	If dev->base_addr == 1, always return failure.
	If dev->base_addr == 2, (detachable devices only) allocate space for the
	device and return success.
	*/

struct net_device * __init el16_probe(int unit)
{
	struct net_device *dev = alloc_etherdev(sizeof(struct net_local));
	static unsigned ports[] = { 0x300, 0x320, 0x340, 0x280, 0};
	unsigned *port;
	int err = -ENODEV;

	if (!dev)
		return ERR_PTR(-ENODEV);

	if (unit >= 0) {
		sprintf(dev->name, "eth%d", unit);
		netdev_boot_setup_check(dev);
		io = dev->base_addr;
		irq = dev->irq;
		mem_start = dev->mem_start & 15;
	}

	if (io > 0x1ff) 	/* Check a single specified location. */
		err = el16_probe1(dev, io);
	else if (io != 0)
		err = -ENXIO;		/* Don't probe at all. */
	else {
		for (port = ports; *port; port++) {
			err = el16_probe1(dev, *port);
			if (!err)
				break;
		}
	}

	if (err)
		goto out;
	err = register_netdev(dev);
	if (err)
		goto out1;
	return dev;
out1:
	free_irq(dev->irq, dev);
	iounmap(((struct net_local *)netdev_priv(dev))->base);
	release_region(dev->base_addr, EL16_IO_EXTENT);
out:
	free_netdev(dev);
	return ERR_PTR(err);
}

static const struct net_device_ops netdev_ops = {
	.ndo_open		= el16_open,
	.ndo_stop		= el16_close,
	.ndo_start_xmit 	= el16_send_packet,
	.ndo_tx_timeout 	= el16_tx_timeout,
	.ndo_change_mtu		= eth_change_mtu,
	.ndo_set_mac_address 	= eth_mac_addr,
	.ndo_validate_addr	= eth_validate_addr,
};

static int __init el16_probe1(struct net_device *dev, int ioaddr)
{
	static unsigned char init_ID_done;
	int i, irq, irqval, retval;
	struct net_local *lp;

	if (init_ID_done == 0) {
		ushort lrs_state = 0xff;
		/* Send the ID sequence to the ID_PORT to enable the board(s). */
		outb(0x00, ID_PORT);
		for(i = 0; i < 255; i++) {
			outb(lrs_state, ID_PORT);
			lrs_state <<= 1;
			if (lrs_state & 0x100)
				lrs_state ^= 0xe7;
		}
		outb(0x00, ID_PORT);
		init_ID_done = 1;
	}

	if (!request_region(ioaddr, EL16_IO_EXTENT, DRV_NAME))
		return -ENODEV;

	if ((inb(ioaddr) != '*') || (inb(ioaddr + 1) != '3') ||
	    (inb(ioaddr + 2) != 'C') || (inb(ioaddr + 3) != 'O')) {
		retval = -ENODEV;
		goto out;
	}

	pr_info("%s: 3c507 at %#x,", dev->name, ioaddr);

	/* We should make a few more checks here, like the first three octets of
	   the S.A. for the manufacturer's code. */

	irq = inb(ioaddr + IRQ_CONFIG) & 0x0f;

	irqval = request_irq(irq, el16_interrupt, 0, DRV_NAME, dev);
	if (irqval) {
		pr_cont("\n");
		pr_err("3c507: unable to get IRQ %d (irqval=%d).\n", irq, irqval);
		retval = -EAGAIN;
		goto out;
	}

	/* We've committed to using the board, and can start filling in *dev. */
	dev->base_addr = ioaddr;

	outb(0x01, ioaddr + MISC_CTRL);
	for (i = 0; i < 6; i++)
		dev->dev_addr[i] = inb(ioaddr + i);
	pr_cont(" %pM", dev->dev_addr);

	if (mem_start)
		net_debug = mem_start & 7;

#ifdef MEM_BASE
	dev->mem_start = MEM_BASE;
	dev->mem_end = dev->mem_start + 0x10000;
#else
	{
		int base;
		int size;
		char mem_config = inb(ioaddr + MEM_CONFIG);
		if (mem_config & 0x20) {
			size = 64*1024;
			base = 0xf00000 + (mem_config & 0x08 ? 0x080000
							   : ((mem_config & 3) << 17));
		} else {
			size = ((mem_config & 3) + 1) << 14;
			base = 0x0c0000 + ( (mem_config & 0x18) << 12);
		}
		dev->mem_start = base;
		dev->mem_end = base + size;
	}
#endif

	dev->if_port = (inb(ioaddr + ROM_CONFIG) & 0x80) ? 1 : 0;
	dev->irq = inb(ioaddr + IRQ_CONFIG) & 0x0f;

	pr_cont(", IRQ %d, %sternal xcvr, memory %#lx-%#lx.\n", dev->irq,
		   dev->if_port ? "ex" : "in", dev->mem_start, dev->mem_end-1);

	if (net_debug)
		pr_debug("%s", version);

	lp = netdev_priv(dev);
	spin_lock_init(&lp->lock);
	lp->base = ioremap(dev->mem_start, RX_BUF_END);
	if (!lp->base) {
		pr_err("3c507: unable to remap memory\n");
		retval = -EAGAIN;
		goto out1;
	}

	dev->netdev_ops = &netdev_ops;
	dev->watchdog_timeo = TX_TIMEOUT;
	dev->ethtool_ops = &netdev_ethtool_ops;
 	dev->flags &= ~IFF_MULTICAST;	/* Multicast doesn't work */
	return 0;
out1:
	free_irq(dev->irq, dev);
out:
	release_region(ioaddr, EL16_IO_EXTENT);
	return retval;
}

static int el16_open(struct net_device *dev)
{
	/* Initialize the 82586 memory and start it. */
	init_82586_mem(dev);

	netif_start_queue(dev);
	return 0;
}


static void el16_tx_timeout (struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	int ioaddr = dev->base_addr;
	void __iomem *shmem = lp->base;

	if (net_debug > 1)
		pr_debug("%s: transmit timed out, %s?  ", dev->name,
			readw(shmem + iSCB_STATUS) & 0x8000 ? "IRQ conflict" :
			"network cable problem");
	/* Try to restart the adaptor. */
	if (lp->last_restart == dev->stats.tx_packets) {
		if (net_debug > 1)
			pr_cont("Resetting board.\n");
		/* Completely reset the adaptor. */
		init_82586_mem (dev);
		lp->tx_pkts_in_ring = 0;
	} else {
		/* Issue the channel attention signal and hope it "gets better". */
		if (net_debug > 1)
			pr_cont("Kicking board.\n");
		writew(0xf000 | CUC_START | RX_START, shmem + iSCB_CMD);
		outb (0, ioaddr + SIGNAL_CA);	/* Issue channel-attn. */
		lp->last_restart = dev->stats.tx_packets;
	}
	dev->trans_start = jiffies;
	netif_wake_queue (dev);
}


static netdev_tx_t el16_send_packet (struct sk_buff *skb,
				     struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	int ioaddr = dev->base_addr;
	unsigned long flags;
	short length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
	unsigned char *buf = skb->data;

	netif_stop_queue (dev);

	spin_lock_irqsave (&lp->lock, flags);

	dev->stats.tx_bytes += length;
	/* Disable the 82586's input to the interrupt line. */
	outb (0x80, ioaddr + MISC_CTRL);

	hardware_send_packet (dev, buf, skb->len, length - skb->len);

	dev->trans_start = jiffies;
	/* Enable the 82586 interrupt input. */
	outb (0x84, ioaddr + MISC_CTRL);

	spin_unlock_irqrestore (&lp->lock, flags);

	dev_kfree_skb (skb);

	/* You might need to clean up and record Tx statistics here. */

	return NETDEV_TX_OK;
}

/*	The typical workload of the driver:
	Handle the network interface interrupts. */
static irqreturn_t el16_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct net_local *lp;
	int ioaddr, status, boguscount = 0;
	ushort ack_cmd = 0;
	void __iomem *shmem;

	if (dev == NULL) {
		pr_err("%s: net_interrupt(): irq %d for unknown device.\n",
			dev->name, irq);
		return IRQ_NONE;
	}

	ioaddr = dev->base_addr;
	lp = netdev_priv(dev);
	shmem = lp->base;

	spin_lock(&lp->lock);

	status = readw(shmem+iSCB_STATUS);

	if (net_debug > 4) {
		pr_debug("%s: 3c507 interrupt, status %4.4x.\n", dev->name, status);
	}

	/* Disable the 82586's input to the interrupt line. */
	outb(0x80, ioaddr + MISC_CTRL);

	/* Reap the Tx packet buffers. */
	while (lp->tx_pkts_in_ring) {
	  unsigned short tx_status = readw(shmem+lp->tx_reap);
	  if (!(tx_status & 0x8000)) {
		if (net_debug > 5)
			pr_debug("Tx command incomplete (%#x).\n", lp->tx_reap);
		break;
	  }
	  /* Tx unsuccessful or some interesting status bit set. */
	  if (!(tx_status & 0x2000) || (tx_status & 0x0f3f)) {
		dev->stats.tx_errors++;
		if (tx_status & 0x0600)  dev->stats.tx_carrier_errors++;
		if (tx_status & 0x0100)  dev->stats.tx_fifo_errors++;
		if (!(tx_status & 0x0040))  dev->stats.tx_heartbeat_errors++;
		if (tx_status & 0x0020)  dev->stats.tx_aborted_errors++;
		dev->stats.collisions += tx_status & 0xf;
	  }
	  dev->stats.tx_packets++;
	  if (net_debug > 5)
		  pr_debug("Reaped %x, Tx status %04x.\n" , lp->tx_reap, tx_status);
	  lp->tx_reap += TX_BUF_SIZE;
	  if (lp->tx_reap > RX_BUF_START - TX_BUF_SIZE)
		lp->tx_reap = TX_BUF_START;

	  lp->tx_pkts_in_ring--;
	  /* There is always more space in the Tx ring buffer now. */
	  netif_wake_queue(dev);

	  if (++boguscount > 10)
		break;
	}

	if (status & 0x4000) { /* Packet received. */
		if (net_debug > 5)
			pr_debug("Received packet, rx_head %04x.\n", lp->rx_head);
		el16_rx(dev);
	}

	/* Acknowledge the interrupt sources. */
	ack_cmd = status & 0xf000;

	if ((status & 0x0700) != 0x0200 && netif_running(dev)) {
		if (net_debug)
			pr_debug("%s: Command unit stopped, status %04x, restarting.\n",
				   dev->name, status);
		/* If this ever occurs we should really re-write the idle loop, reset
		   the Tx list, and do a complete restart of the command unit.
		   For now we rely on the Tx timeout if the resume doesn't work. */
		ack_cmd |= CUC_RESUME;
	}

	if ((status & 0x0070) != 0x0040 && netif_running(dev)) {
		/* The Rx unit is not ready, it must be hung.  Restart the receiver by
		   initializing the rx buffers, and issuing an Rx start command. */
		if (net_debug)
			pr_debug("%s: Rx unit stopped, status %04x, restarting.\n",
				   dev->name, status);
		init_rx_bufs(dev);
		writew(RX_BUF_START,shmem+iSCB_RFA);
		ack_cmd |= RX_START;
	}

	writew(ack_cmd,shmem+iSCB_CMD);
	outb(0, ioaddr + SIGNAL_CA);			/* Issue channel-attn. */

	/* Clear the latched interrupt. */
	outb(0, ioaddr + RESET_IRQ);

	/* Enable the 82586's interrupt input. */
	outb(0x84, ioaddr + MISC_CTRL);
	spin_unlock(&lp->lock);
	return IRQ_HANDLED;
}

static int el16_close(struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	int ioaddr = dev->base_addr;
	void __iomem *shmem = lp->base;

	netif_stop_queue(dev);

	/* Flush the Tx and disable Rx. */
	writew(RX_SUSPEND | CUC_SUSPEND,shmem+iSCB_CMD);
	outb(0, ioaddr + SIGNAL_CA);

	/* Disable the 82586's input to the interrupt line. */
	outb(0x80, ioaddr + MISC_CTRL);

	/* We always physically use the IRQ line, so we don't do free_irq(). */

	/* Update the statistics here. */

	return 0;
}

/* Initialize the Rx-block list. */
static void init_rx_bufs(struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	void __iomem *write_ptr;
	unsigned short SCB_base = SCB_BASE;

	int cur_rxbuf = lp->rx_head = RX_BUF_START;

	/* Initialize each Rx frame + data buffer. */
	do {	/* While there is room for one more. */

		write_ptr = lp->base + cur_rxbuf;

		writew(0x0000,write_ptr);			/* Status */
		writew(0x0000,write_ptr+=2);			/* Command */
		writew(cur_rxbuf + RX_BUF_SIZE,write_ptr+=2);	/* Link */
		writew(cur_rxbuf + 22,write_ptr+=2);		/* Buffer offset */
		writew(0x0000,write_ptr+=2);			/* Pad for dest addr. */
		writew(0x0000,write_ptr+=2);
		writew(0x0000,write_ptr+=2);
		writew(0x0000,write_ptr+=2);			/* Pad for source addr. */
		writew(0x0000,write_ptr+=2);
		writew(0x0000,write_ptr+=2);
		writew(0x0000,write_ptr+=2);			/* Pad for protocol. */

		writew(0x0000,write_ptr+=2);			/* Buffer: Actual count */
		writew(-1,write_ptr+=2);			/* Buffer: Next (none). */
		writew(cur_rxbuf + 0x20 + SCB_base,write_ptr+=2);/* Buffer: Address low */
		writew(0x0000,write_ptr+=2);
		/* Finally, the number of bytes in the buffer. */
		writew(0x8000 + RX_BUF_SIZE-0x20,write_ptr+=2);

		lp->rx_tail = cur_rxbuf;
		cur_rxbuf += RX_BUF_SIZE;
	} while (cur_rxbuf <= RX_BUF_END - RX_BUF_SIZE);

	/* Terminate the list by setting the EOL bit, and wrap the pointer to make
	   the list a ring. */
	write_ptr = lp->base + lp->rx_tail + 2;
	writew(0xC000,write_ptr);				/* Command, mark as last. */
	writew(lp->rx_head,write_ptr+2);			/* Link */
}

static void init_82586_mem(struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	short ioaddr = dev->base_addr;
	void __iomem *shmem = lp->base;

	/* Enable loopback to protect the wire while starting up,
	   and hold the 586 in reset during the memory initialization. */
	outb(0x20, ioaddr + MISC_CTRL);

	/* Fix the ISCP address and base. */
	init_words[3] = SCB_BASE;
	init_words[7] = SCB_BASE;

	/* Write the words at 0xfff6 (address-aliased to 0xfffff6). */
	memcpy_toio(lp->base + RX_BUF_END - 10, init_words, 10);

	/* Write the words at 0x0000. */
	memcpy_toio(lp->base, init_words + 5, sizeof(init_words) - 10);

	/* Fill in the station address. */
	memcpy_toio(lp->base+SA_OFFSET, dev->dev_addr, ETH_ALEN);

	/* The Tx-block list is written as needed.  We just set up the values. */
	lp->tx_cmd_link = IDLELOOP + 4;
	lp->tx_head = lp->tx_reap = TX_BUF_START;

	init_rx_bufs(dev);

	/* Start the 586 by releasing the reset line, but leave loopback. */
	outb(0xA0, ioaddr + MISC_CTRL);

	/* This was time consuming to track down: you need to give two channel
	   attention signals to reliably start up the i82586. */
	outb(0, ioaddr + SIGNAL_CA);

	{
		int boguscnt = 50;
		while (readw(shmem+iSCB_STATUS) == 0)
			if (--boguscnt == 0) {
				pr_warning("%s: i82586 initialization timed out with status %04x, cmd %04x.\n",
					dev->name, readw(shmem+iSCB_STATUS), readw(shmem+iSCB_CMD));
				break;
			}
		/* Issue channel-attn -- the 82586 won't start. */
		outb(0, ioaddr + SIGNAL_CA);
	}

	/* Disable loopback and enable interrupts. */
	outb(0x84, ioaddr + MISC_CTRL);
	if (net_debug > 4)
		pr_debug("%s: Initialized 82586, status %04x.\n", dev->name,
			   readw(shmem+iSCB_STATUS));
	return;
}

static void hardware_send_packet(struct net_device *dev, void *buf, short length, short pad)
{
	struct net_local *lp = netdev_priv(dev);
	short ioaddr = dev->base_addr;
	ushort tx_block = lp->tx_head;
	void __iomem *write_ptr = lp->base + tx_block;
	static char padding[ETH_ZLEN];

	/* Set the write pointer to the Tx block, and put out the header. */
	writew(0x0000,write_ptr);			/* Tx status */
	writew(CMD_INTR|CmdTx,write_ptr+=2);		/* Tx command */
	writew(tx_block+16,write_ptr+=2);		/* Next command is a NoOp. */
	writew(tx_block+8,write_ptr+=2);			/* Data Buffer offset. */

	/* Output the data buffer descriptor. */
	writew((pad + length) | 0x8000,write_ptr+=2);		/* Byte count parameter. */
	writew(-1,write_ptr+=2);			/* No next data buffer. */
	writew(tx_block+22+SCB_BASE,write_ptr+=2);	/* Buffer follows the NoOp command. */
	writew(0x0000,write_ptr+=2);			/* Buffer address high bits (always zero). */

	/* Output the Loop-back NoOp command. */
	writew(0x0000,write_ptr+=2);			/* Tx status */
	writew(CmdNOp,write_ptr+=2);			/* Tx command */
	writew(tx_block+16,write_ptr+=2);		/* Next is myself. */

	/* Output the packet at the write pointer. */
	memcpy_toio(write_ptr+2, buf, length);
	if (pad)
		memcpy_toio(write_ptr+length+2, padding, pad);

	/* Set the old command link pointing to this send packet. */
	writew(tx_block,lp->base + lp->tx_cmd_link);
	lp->tx_cmd_link = tx_block + 20;

	/* Set the next free tx region. */
	lp->tx_head = tx_block + TX_BUF_SIZE;
	if (lp->tx_head > RX_BUF_START - TX_BUF_SIZE)
		lp->tx_head = TX_BUF_START;

	if (net_debug > 4) {
		pr_debug("%s: 3c507 @%x send length = %d, tx_block %3x, next %3x.\n",
			   dev->name, ioaddr, length, tx_block, lp->tx_head);
	}

	/* Grimly block further packets if there has been insufficient reaping. */
	if (++lp->tx_pkts_in_ring < NUM_TX_BUFS)
		netif_wake_queue(dev);
}

static void el16_rx(struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	void __iomem *shmem = lp->base;
	ushort rx_head = lp->rx_head;
	ushort rx_tail = lp->rx_tail;
	ushort boguscount = 10;
	short frame_status;

	while ((frame_status = readw(shmem+rx_head)) < 0) {   /* Command complete */
		void __iomem *read_frame = lp->base + rx_head;
		ushort rfd_cmd = readw(read_frame+2);
		ushort next_rx_frame = readw(read_frame+4);
		ushort data_buffer_addr = readw(read_frame+6);
		void __iomem *data_frame = lp->base + data_buffer_addr;
		ushort pkt_len = readw(data_frame);

		if (rfd_cmd != 0 || data_buffer_addr != rx_head + 22 ||
		    (pkt_len & 0xC000) != 0xC000) {
			pr_err("%s: Rx frame at %#x corrupted, "
			       "status %04x cmd %04x next %04x "
			       "data-buf @%04x %04x.\n",
			       dev->name, rx_head, frame_status, rfd_cmd,
			       next_rx_frame, data_buffer_addr, pkt_len);
		} else if ((frame_status & 0x2000) == 0) {
			/* Frame Rxed, but with error. */
			dev->stats.rx_errors++;
			if (frame_status & 0x0800) dev->stats.rx_crc_errors++;
			if (frame_status & 0x0400) dev->stats.rx_frame_errors++;
			if (frame_status & 0x0200) dev->stats.rx_fifo_errors++;
			if (frame_status & 0x0100) dev->stats.rx_over_errors++;
			if (frame_status & 0x0080) dev->stats.rx_length_errors++;
		} else {
			/* Malloc up new buffer. */
			struct sk_buff *skb;

			pkt_len &= 0x3fff;
			skb = dev_alloc_skb(pkt_len+2);
			if (skb == NULL) {
				pr_err("%s: Memory squeeze, dropping packet.\n",
				       dev->name);
				dev->stats.rx_dropped++;
				break;
			}

			skb_reserve(skb,2);

			/* 'skb->data' points to the start of sk_buff data area. */
			memcpy_fromio(skb_put(skb,pkt_len), data_frame + 10, pkt_len);

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

		/* Clear the status word and set End-of-List on the rx frame. */
		writew(0,read_frame);
		writew(0xC000,read_frame+2);
		/* Clear the end-of-list on the prev. RFD. */
		writew(0x0000,lp->base + rx_tail + 2);

		rx_tail = rx_head;
		rx_head = next_rx_frame;
		if (--boguscount == 0)
			break;
	}

	lp->rx_head = rx_head;
	lp->rx_tail = rx_tail;
}

static void netdev_get_drvinfo(struct net_device *dev,
			       struct ethtool_drvinfo *info)
{
	strcpy(info->driver, DRV_NAME);
	strcpy(info->version, DRV_VERSION);
	sprintf(info->bus_info, "ISA 0x%lx", dev->base_addr);
}

static u32 netdev_get_msglevel(struct net_device *dev)
{
	return debug;
}

static void netdev_set_msglevel(struct net_device *dev, u32 level)
{
	debug = level;
}

static const struct ethtool_ops netdev_ethtool_ops = {
	.get_drvinfo		= netdev_get_drvinfo,
	.get_msglevel		= netdev_get_msglevel,
	.set_msglevel		= netdev_set_msglevel,
};

#ifdef MODULE
static struct net_device *dev_3c507;
module_param(io, int, 0);
module_param(irq, int, 0);
MODULE_PARM_DESC(io, "EtherLink16 I/O base address");
MODULE_PARM_DESC(irq, "(ignored)");

int __init init_module(void)
{
	if (io == 0)
		pr_notice("3c507: You should not use auto-probing with insmod!\n");
	dev_3c507 = el16_probe(-1);
	return IS_ERR(dev_3c507) ? PTR_ERR(dev_3c507) : 0;
}

void __exit
cleanup_module(void)
{
	struct net_device *dev = dev_3c507;
	unregister_netdev(dev);
	free_irq(dev->irq, dev);
	iounmap(((struct net_local *)netdev_priv(dev))->base);
	release_region(dev->base_addr, EL16_IO_EXTENT);
	free_netdev(dev);
}
#endif /* MODULE */
MODULE_LICENSE("GPL");