summaryrefslogtreecommitdiffstats
path: root/drivers/net/atp.c
blob: 658c894b948f231dfe8a61454101e00ba1d9aa16 (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
/* atp.c: Attached (pocket) ethernet adapter driver for linux. */
/*
	This is a driver for a commonly OEMed pocket (parallel port)
	ethernet adapter.  

	Written 1993,1994,1995 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 Public License, incorporated herein by reference.

	The author may be reached as becker@CESDIS.gsfc.nasa.gov, or C/O
	Center of Excellence in Space Data and Information Sciences
		Code 930.5, Goddard Space Flight Center, Greenbelt MD 20771

	The timer-based reset code was written by Bill Carlson, wwc@super.org.
*/

static const char *version =
	"atp.c:v1.01 1/18/95 Donald Becker (becker@cesdis.gsfc.nasa.gov)\n";

/*
	This file is a device driver for the RealTek (aka AT-Lan-Tec) pocket
	ethernet adapter.  This is a common low-cost OEM pocket ethernet
	adapter, sold under many names.

  Sources:
	This driver was written from the packet driver assembly code provided by
	Vincent Bono of AT-Lan-Tec.	 Ever try to figure out how a complicated
	device works just from the assembly code?  It ain't pretty.  The following
	description is written based on guesses and writing lots of special-purpose
	code to test my theorized operation.

					Theory of Operation
	
	The RTL8002 adapter seems to be built around a custom spin of the SEEQ
	controller core.  It probably has a 16K or 64K internal packet buffer, of
	which the first 4K is devoted to transmit and the rest to receive.
	The controller maintains the queue of received packet and the packet buffer
	access pointer internally, with only 'reset to beginning' and 'skip to next
	packet' commands visible.  The transmit packet queue holds two (or more?)
	packets: both 'retransmit this packet' (due to collision) and 'transmit next
	packet' commands must be started by hand.

	The station address is stored in a standard bit-serial EEPROM which must be
	read (ughh) by the device driver.  (Provisions have been made for
	substituting a 74S288 PROM, but I haven't gotten reports of any models
	using it.)  Unlike built-in devices, a pocket adapter can temporarily lose
	power without indication to the device driver.  The major effect is that
	the station address, receive filter (promiscuous, etc.) and transceiver
	must be reset.

	The controller itself has 16 registers, some of which use only the lower
	bits.  The registers are read and written 4 bits at a time.  The four bit
	register address is presented on the data lines along with a few additional
	timing and control bits.  The data is then read from status port or written
	to the data port.

	Since the bulk data transfer of the actual packets through the slow
	parallel port dominates the driver's running time, four distinct data
	(non-register) transfer modes are provided by the adapter, two in each
	direction.  In the first mode timing for the nibble transfers is
	provided through the data port.  In the second mode the same timing is
	provided through the control port.  In either case the data is read from
	the status port and written to the data port, just as it is accessing
	registers.

	In addition to the basic data transfer methods, several more are modes are
	created by adding some delay by doing multiple reads of the data to allow
	it to stabilize.  This delay seems to be needed on most machines.

	The data transfer mode is stored in the 'dev->if_port' field.  Its default
	value is '4'.  It may be overridden at boot-time using the third parameter
	to the "ether=..." initialization.

	The header file <atp.h> provides inline functions that encapsulate the
	register and data access methods.  These functions are hand-tuned to
	generate reasonable object code.  This header file also documents my
	interpretations of the device registers.
*/

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/malloc.h>
#include <linux/string.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <linux/errno.h>
#include <linux/init.h>

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>

#include "atp.h"

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

/* The number of low I/O ports used by the ethercard. */
#define ETHERCARD_TOTAL_SIZE	3

/* This code, written by wwc@super.org, resets the adapter every
   TIMED_CHECKER ticks.  This recovers from an unknown error which
   hangs the device. */
#define TIMED_CHECKER (HZ/4)
#ifdef TIMED_CHECKER
#include <linux/timer.h>
static void atp_timed_checker(unsigned long ignored);
static struct device *atp_timed_dev;
static struct timer_list atp_timer = {NULL, NULL, 0, 0, atp_timed_checker};
#endif

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

extern int atp_probe(struct device *dev);

static int atp_probe1(struct device *dev, short ioaddr);
static void get_node_ID(struct device *dev);
static unsigned short eeprom_op(short ioaddr, unsigned int cmd);
static int net_open(struct device *dev);
static void hardware_init(struct device *dev);
static void write_packet(short ioaddr, int length, unsigned char *packet, int mode);
static void trigger_send(short ioaddr, int length);
static int	net_send_packet(struct sk_buff *skb, struct device *dev);
static void net_interrupt(int irq, void *dev_id, struct pt_regs *regs);
static void net_rx(struct device *dev);
static void read_block(short ioaddr, int length, unsigned char *buffer, int data_mode);
static int net_close(struct device *dev);
static struct net_device_stats *net_get_stats(struct device *dev);
static void set_multicast_list(struct device *dev);


/* Check for a network adapter 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, allocate space for the device and return success
   (detachable devices only).
   */
__initfunc(int
atp_init(struct device *dev))
{
	int *port, ports[] = {0x378, 0x278, 0x3bc, 0};
	int base_addr = dev->base_addr;

	if (base_addr > 0x1ff)		/* Check a single specified location. */
		return atp_probe1(dev, base_addr);
	else if (base_addr == 1)	/* Don't probe at all. */
		return ENXIO;

	for (port = ports; *port; port++) {
		int ioaddr = *port;
		outb(0x57, ioaddr + PAR_DATA);
		if (inb(ioaddr + PAR_DATA) != 0x57)
			continue;
		if (atp_probe1(dev, ioaddr) == 0)
			return 0;
	}

	return ENODEV;
}

__initfunc(static int atp_probe1(struct device *dev, short ioaddr))
{
	int saved_ctrl_reg, status;

	outb(0xff, ioaddr + PAR_DATA);
	/* Save the original value of the Control register, in case we guessed
	   wrong. */
	saved_ctrl_reg = inb(ioaddr + PAR_CONTROL);
	/* IRQEN=0, SLCTB=high INITB=high, AUTOFDB=high, STBB=high. */
	outb(0x04, ioaddr + PAR_CONTROL);
	write_reg_high(ioaddr, CMR1, CMR1h_RESET);
	eeprom_delay(2048);
	status = read_nibble(ioaddr, CMR1);

	if ((status & 0x78) != 0x08) {
		/* The pocket adapter probe failed, restore the control register. */
		outb(saved_ctrl_reg, ioaddr + PAR_CONTROL);
		return 1;
	}
	status = read_nibble(ioaddr, CMR2_h);
	if ((status & 0x78) != 0x10) {
		outb(saved_ctrl_reg, ioaddr + PAR_CONTROL);
		return 1;
	}
	/* Find the IRQ used by triggering an interrupt. */
	write_reg_byte(ioaddr, CMR2, 0x01);			/* No accept mode, IRQ out. */
	write_reg_high(ioaddr, CMR1, CMR1h_RxENABLE | CMR1h_TxENABLE);	/* Enable Tx and Rx. */

	/* Omit autoIRQ routine for now. Use "table lookup" instead.  Uhgggh. */
	if (ioaddr == 0x378)
		dev->irq = 7;
	else
		dev->irq = 5;
	write_reg_high(ioaddr, CMR1, CMR1h_TxRxOFF); /* Disable Tx and Rx units. */
	write_reg(ioaddr, CMR2, CMR2_NULL);

	dev->base_addr = ioaddr;

	/* Read the station address PROM.  */
	get_node_ID(dev);

	printk("%s: Pocket adapter found at %#3lx, IRQ %d, SAPROM "
		   "%02X:%02X:%02X:%02X:%02X:%02X.\n", dev->name, dev->base_addr,
		   dev->irq, dev->dev_addr[0], dev->dev_addr[1], dev->dev_addr[2],
		   dev->dev_addr[3], dev->dev_addr[4], dev->dev_addr[5]);

	/* Leave the hardware in a reset state. */
    write_reg_high(ioaddr, CMR1, CMR1h_RESET);

	if (net_debug)
		printk(version);

	/* Initialize the device structure. */
	ether_setup(dev);
	dev->priv = kmalloc(sizeof(struct net_local), GFP_KERNEL);
	if (dev->priv == NULL)
		return -ENOMEM;
	memset(dev->priv, 0, sizeof(struct net_local));


	{
		struct net_local *lp = (struct net_local *)dev->priv;
		lp->addr_mode = CMR2h_Normal;
	}

	/* For the ATP adapter the "if_port" is really the data transfer mode. */
	dev->if_port = (dev->mem_start & 0xf) ? dev->mem_start & 0x7 : 4;
	if (dev->mem_end & 0xf)
		net_debug = dev->mem_end & 7;

	dev->open		= net_open;
	dev->stop		= net_close;
	dev->hard_start_xmit = net_send_packet;
	dev->get_stats	= net_get_stats;
	dev->set_multicast_list = &set_multicast_list;

#ifdef TIMED_CHECKER
	del_timer(&atp_timer);
	atp_timer.expires = jiffies + TIMED_CHECKER;
	atp_timed_dev = dev;
	add_timer(&atp_timer);
#endif
	return 0;
}

/* Read the station address PROM, usually a word-wide EEPROM. */
__initfunc(static void get_node_ID(struct device *dev))
{
	short ioaddr = dev->base_addr;
	int sa_offset = 0;
	int i;
	
	write_reg(ioaddr, CMR2, CMR2_EEPROM);	  /* Point to the EEPROM control registers. */
	
	/* Some adapters have the station address at offset 15 instead of offset
	   zero.  Check for it, and fix it if needed. */
	if (eeprom_op(ioaddr, EE_READ(0)) == 0xffff)
		sa_offset = 15;
	
	for (i = 0; i < 3; i++)
		((unsigned short *)dev->dev_addr)[i] =
			ntohs(eeprom_op(ioaddr, EE_READ(sa_offset + i)));
	
	write_reg(ioaddr, CMR2, CMR2_NULL);
}

/*
  An EEPROM read command starts by shifting out 0x60+address, and then
  shifting in the serial data. See the NatSemi databook for details.
 *		   ________________
 * CS : __|
 *			   ___	   ___
 * CLK: ______|	  |___|	  |
 *		 __ _______ _______
 * DI :	 __X_______X_______X
 * DO :	 _________X_______X
 */

__initfunc(static unsigned short eeprom_op(short ioaddr, unsigned int cmd))
{
	unsigned eedata_out = 0;
	int num_bits = EE_CMD_SIZE;
	
	while (--num_bits >= 0) {
		char outval = test_bit(num_bits, &cmd) ? EE_DATA_WRITE : 0;
		write_reg_high(ioaddr, PROM_CMD, outval | EE_CLK_LOW);
		eeprom_delay(5);
		write_reg_high(ioaddr, PROM_CMD, outval | EE_CLK_HIGH);
		eedata_out <<= 1;
		if (read_nibble(ioaddr, PROM_DATA) & EE_DATA_READ)
			eedata_out++;
		eeprom_delay(5);
	}
	write_reg_high(ioaddr, PROM_CMD, EE_CLK_LOW & ~EE_CS);
	return eedata_out;
}


/* Open/initialize the board.  This is called (in the current kernel)
   sometime after booting when the 'ifconfig' program is run.

   This routine sets everything up anew at each open, even
   registers that "should" only need to be set once at boot, so that
   there is non-reboot way to recover if something goes wrong.

   This is an attachable device: if there is no dev->priv entry then it wasn't
   probed for at boot-time, and we need to probe for it again.
   */
static int net_open(struct device *dev)
{

	/* The interrupt line is turned off (tri-stated) when the device isn't in
	   use.  That's especially important for "attached" interfaces where the
	   port or interrupt may be shared. */
	if (request_irq(dev->irq, &net_interrupt, 0, "ATP", dev)) {
		return -EAGAIN;
	}

	hardware_init(dev);
	dev->start = 1;
	return 0;
}

/* This routine resets the hardware.  We initialize everything, assuming that
   the hardware may have been temporarily detached. */
static void hardware_init(struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	int ioaddr = dev->base_addr;
    int i;

	write_reg_high(ioaddr, CMR1, CMR1h_RESET);
	
    for (i = 0; i < 6; i++)
		write_reg_byte(ioaddr, PAR0 + i, dev->dev_addr[i]);

	write_reg_high(ioaddr, CMR2, lp->addr_mode);

	if (net_debug > 2) {
		printk("%s: Reset: current Rx mode %d.\n", dev->name,
			   (read_nibble(ioaddr, CMR2_h) >> 3) & 0x0f);
	}

    write_reg(ioaddr, CMR2, CMR2_IRQOUT);
    write_reg_high(ioaddr, CMR1, CMR1h_RxENABLE | CMR1h_TxENABLE);

	/* Enable the interrupt line from the serial port. */
	outb(Ctrl_SelData + Ctrl_IRQEN, ioaddr + PAR_CONTROL);

	/* Unmask the interesting interrupts. */
    write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
    write_reg_high(ioaddr, IMR, ISRh_RxErr);

	lp->tx_unit_busy = 0;
    lp->pac_cnt_in_tx_buf = 0;
	lp->saved_tx_size = 0;

	dev->tbusy = 0;
	dev->interrupt = 0;
}

static void trigger_send(short ioaddr, int length)
{
	write_reg_byte(ioaddr, TxCNT0, length & 0xff);
	write_reg(ioaddr, TxCNT1, length >> 8);
	write_reg(ioaddr, CMR1, CMR1_Xmit);
}

static void write_packet(short ioaddr, int length, unsigned char *packet, int data_mode)
{
    length = (length + 1) & ~1;		/* Round up to word length. */
    outb(EOC+MAR, ioaddr + PAR_DATA);
    if ((data_mode & 1) == 0) {
		/* Write the packet out, starting with the write addr. */
		outb(WrAddr+MAR, ioaddr + PAR_DATA);
		do {
			write_byte_mode0(ioaddr, *packet++);
		} while (--length > 0) ;
    } else {
		/* Write the packet out in slow mode. */
		unsigned char outbyte = *packet++;

		outb(Ctrl_LNibWrite + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
		outb(WrAddr+MAR, ioaddr + PAR_DATA);

		outb((outbyte & 0x0f)|0x40, ioaddr + PAR_DATA);
		outb(outbyte & 0x0f, ioaddr + PAR_DATA);
		outbyte >>= 4;
		outb(outbyte & 0x0f, ioaddr + PAR_DATA);
		outb(Ctrl_HNibWrite + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
		while (--length > 0)
			write_byte_mode1(ioaddr, *packet++);
    }
    /* Terminate the Tx frame.  End of write: ECB. */
    outb(0xff, ioaddr + PAR_DATA);
    outb(Ctrl_HNibWrite | Ctrl_SelData | Ctrl_IRQEN, ioaddr + PAR_CONTROL);
}

static int
net_send_packet(struct sk_buff *skb, struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	int ioaddr = dev->base_addr;

	if (dev->tbusy) {
		/* If we get here, some higher level has decided we are broken.
		   There should really be a "kick me" function call instead. */
		int tickssofar = jiffies - dev->trans_start;
		if (tickssofar < 5)
			return 1;
		printk("%s: transmit timed out, %s?\n", dev->name,
			   inb(ioaddr + PAR_CONTROL) & 0x10 ? "network cable problem"
			   :  "IRQ conflict");
		lp->stats.tx_errors++;
		/* Try to restart the adapter. */
		hardware_init(dev);
		dev->tbusy=0;
		dev->trans_start = jiffies;
	}

	/* Block a timer-based transmit from overlapping.  This could better be
	   done with atomic_swap(1, dev->tbusy), but set_bit() works as well. */
	if (test_and_set_bit(0, (void*)&dev->tbusy) != 0)
		printk("%s: Transmitter access conflict.\n", dev->name);
	else {
		short length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
		unsigned char *buf = skb->data;
		int flags;

		/* Disable interrupts by writing 0x00 to the Interrupt Mask Register.
		   This sequence must not be interrupted by an incoming packet. */
		save_flags(flags);
		cli();
		write_reg(ioaddr, IMR, 0);
		write_reg_high(ioaddr, IMR, 0);
		restore_flags(flags);

		write_packet(ioaddr, length, buf, dev->if_port);

		lp->pac_cnt_in_tx_buf++;
		if (lp->tx_unit_busy == 0) {
			trigger_send(ioaddr, length);
			lp->saved_tx_size = 0; 				/* Redundant */
			lp->re_tx = 0;
			lp->tx_unit_busy = 1;
		} else
			lp->saved_tx_size = length;

		dev->trans_start = jiffies;
		/* Re-enable the LPT interrupts. */
		write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
		write_reg_high(ioaddr, IMR, ISRh_RxErr);
	}

	dev_kfree_skb (skb);

	return 0;
}

/* The typical workload of the driver:
   Handle the network interface interrupts. */
static void
net_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
	struct device *dev = dev_id;
	struct net_local *lp;
	int ioaddr, status, boguscount = 20;
	static int num_tx_since_rx = 0;

	if (dev == NULL) {
		printk ("ATP_interrupt(): irq %d for unknown device.\n", irq);
		return;
	}
	dev->interrupt = 1;

	ioaddr = dev->base_addr;
	lp = (struct net_local *)dev->priv;

	/* Disable additional spurious interrupts. */
	outb(Ctrl_SelData, ioaddr + PAR_CONTROL);

	/* The adapter's output is currently the IRQ line, switch it to data. */
	write_reg(ioaddr, CMR2, CMR2_NULL);
	write_reg(ioaddr, IMR, 0);

	if (net_debug > 5) printk("%s: In interrupt ", dev->name);
    while (--boguscount > 0) {
		status = read_nibble(ioaddr, ISR);
		if (net_debug > 5) printk("loop status %02x..", status);

		if (status & (ISR_RxOK<<3)) {
			write_reg(ioaddr, ISR, ISR_RxOK); /* Clear the Rx interrupt. */
			do {
				int read_status = read_nibble(ioaddr, CMR1);
				if (net_debug > 6)
					printk("handling Rx packet %02x..", read_status);
				/* We acknowledged the normal Rx interrupt, so if the interrupt
				   is still outstanding we must have a Rx error. */
				if (read_status & (CMR1_IRQ << 3)) { /* Overrun. */
					lp->stats.rx_over_errors++;
					/* Set to no-accept mode long enough to remove a packet. */
					write_reg_high(ioaddr, CMR2, CMR2h_OFF);
					net_rx(dev);
					/* Clear the interrupt and return to normal Rx mode. */
					write_reg_high(ioaddr, ISR, ISRh_RxErr);
					write_reg_high(ioaddr, CMR2, lp->addr_mode);
				} else if ((read_status & (CMR1_BufEnb << 3)) == 0) {
					net_rx(dev);
					dev->last_rx = jiffies;
					num_tx_since_rx = 0;
				} else
					break;
			} while (--boguscount > 0);
		} else if (status & ((ISR_TxErr + ISR_TxOK)<<3)) {
			if (net_debug > 6)  printk("handling Tx done..");
			/* Clear the Tx interrupt.  We should check for too many failures
			   and reinitialize the adapter. */
			write_reg(ioaddr, ISR, ISR_TxErr + ISR_TxOK);
			if (status & (ISR_TxErr<<3)) {
				lp->stats.collisions++;
				if (++lp->re_tx > 15) {
					lp->stats.tx_aborted_errors++;
					hardware_init(dev);
					break;
				}
				/* Attempt to retransmit. */
				if (net_debug > 6)  printk("attempting to ReTx");
				write_reg(ioaddr, CMR1, CMR1_ReXmit + CMR1_Xmit);
			} else {
				/* Finish up the transmit. */
				lp->stats.tx_packets++;
				lp->pac_cnt_in_tx_buf--;
				if ( lp->saved_tx_size) {
					trigger_send(ioaddr, lp->saved_tx_size);
					lp->saved_tx_size = 0;
					lp->re_tx = 0;
				} else
					lp->tx_unit_busy = 0;
				dev->tbusy = 0;
				mark_bh(NET_BH);	/* Inform upper layers. */
			}
			num_tx_since_rx++;
		} else if (num_tx_since_rx > 8
				   && jiffies - dev->last_rx > 100) {
			if (net_debug > 2)
				printk("%s: Missed packet? No Rx after %d Tx and %ld jiffies"
					   " status %02x  CMR1 %02x.\n", dev->name,
					   num_tx_since_rx, jiffies - dev->last_rx, status,
					   (read_nibble(ioaddr, CMR1) >> 3) & 15);
			lp->stats.rx_missed_errors++;
			hardware_init(dev);
			num_tx_since_rx = 0;
			break;
		} else
			break;
    }

	/* This following code fixes a rare (and very difficult to track down)
	   problem where the adapter forgets its ethernet address. */
	{
		int i;
		for (i = 0; i < 6; i++)
			write_reg_byte(ioaddr, PAR0 + i, dev->dev_addr[i]);
#ifdef TIMED_CHECKER
		del_timer(&atp_timer);
		atp_timer.expires = jiffies + TIMED_CHECKER;
		add_timer(&atp_timer);
#endif
	}

	/* Tell the adapter that it can go back to using the output line as IRQ. */
    write_reg(ioaddr, CMR2, CMR2_IRQOUT);
	/* Enable the physical interrupt line, which is sure to be low until.. */
	outb(Ctrl_SelData + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
	/* .. we enable the interrupt sources. */
	write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
	write_reg_high(ioaddr, IMR, ISRh_RxErr); 			/* Hmmm, really needed? */

	if (net_debug > 5) printk("exiting interrupt.\n");

	dev->interrupt = 0;

	return;
}

#ifdef TIMED_CHECKER
/* This following code fixes a rare (and very difficult to track down)
   problem where the adapter forgets its ethernet address. */
static void atp_timed_checker(unsigned long ignored)
{
  int i;
  int ioaddr = atp_timed_dev->base_addr;

  if (!atp_timed_dev->interrupt)
	{
	  for (i = 0; i < 6; i++)
#if 0
		if (read_cmd_byte(ioaddr, PAR0 + i) != atp_timed_dev->dev_addr[i])
		  {
			struct net_local *lp = (struct net_local *)atp_timed_dev->priv;
			write_reg_byte(ioaddr, PAR0 + i, atp_timed_dev->dev_addr[i]);
			if (i == 2)
			  lp->stats.tx_errors++;
			else if (i == 3)
			  lp->stats.tx_dropped++;
			else if (i == 4)
			  lp->stats.collisions++;
			else
			  lp->stats.rx_errors++;
		  }
#else
	  write_reg_byte(ioaddr, PAR0 + i, atp_timed_dev->dev_addr[i]);
#endif
	}
  del_timer(&atp_timer);
  atp_timer.expires = jiffies + TIMED_CHECKER;
  add_timer(&atp_timer);
}
#endif

/* We have a good packet(s), get it/them out of the buffers. */
static void net_rx(struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	int ioaddr = dev->base_addr;
#ifdef notdef
	ushort header[4];
#else
	struct rx_header rx_head;
#endif

	/* Process the received packet. */
	outb(EOC+MAR, ioaddr + PAR_DATA);
	read_block(ioaddr, 8, (unsigned char*)&rx_head, dev->if_port);
	if (net_debug > 5)
		printk(" rx_count %04x %04x %04x %04x..", rx_head.pad,
			   rx_head.rx_count, rx_head.rx_status, rx_head.cur_addr);
	if ((rx_head.rx_status & 0x77) != 0x01) {
		lp->stats.rx_errors++;
		/* Ackkk!  I don't have any documentation on what the error bits mean!
		   The best I can do is slap the device around a bit. */
		if (net_debug > 3) printk("%s: Unknown ATP Rx error %04x.\n",
								  dev->name, rx_head.rx_status);
		hardware_init(dev);
		return;
	} else {
		/* Malloc up new buffer. */
		int pkt_len = (rx_head.rx_count & 0x7ff) - 4; 		/* The "-4" is omits the FCS (CRC). */
		struct sk_buff *skb;
		
		skb = dev_alloc_skb(pkt_len);
		if (skb == NULL) {
			printk("%s: Memory squeeze, dropping packet.\n", dev->name);
			lp->stats.rx_dropped++;
			goto done;
		}
		skb->dev = dev;
		
		read_block(ioaddr, pkt_len, skb_put(skb,pkt_len), dev->if_port);

		if (net_debug > 6) {
			unsigned char *data = skb->data;
			printk(" data %02x%02x%02x %02x%02x%02x %02x%02x%02x"
				   "%02x%02x%02x %02x%02x..",
				   data[0], data[1], data[2], data[3], data[4], data[5],
				   data[6], data[7], data[8], data[9], data[10], data[11],
				   data[12], data[13]);
		}
		
		skb->protocol=eth_type_trans(skb,dev);
		netif_rx(skb);
		lp->stats.rx_packets++;
	}
 done:
	write_reg(ioaddr, CMR1, CMR1_NextPkt);
	return;
}

static void read_block(short ioaddr, int length, unsigned char *p, int data_mode)
{

	if (data_mode <= 3) { /* Mode 0 or 1 */
		outb(Ctrl_LNibRead, ioaddr + PAR_CONTROL);
		outb(length == 8  ?  RdAddr | HNib | MAR  :  RdAddr | MAR,
			 ioaddr + PAR_DATA);
		if (data_mode <= 1) { /* Mode 0 or 1 */
			do  *p++ = read_byte_mode0(ioaddr);  while (--length > 0);
		} else	/* Mode 2 or 3 */
			do  *p++ = read_byte_mode2(ioaddr);  while (--length > 0);
	} else if (data_mode <= 5)
		do      *p++ = read_byte_mode4(ioaddr);  while (--length > 0);
	else
		do      *p++ = read_byte_mode6(ioaddr);  while (--length > 0);

    outb(EOC+HNib+MAR, ioaddr + PAR_DATA);
	outb(Ctrl_SelData, ioaddr + PAR_CONTROL);
}

/* The inverse routine to net_open(). */
static int
net_close(struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	int ioaddr = dev->base_addr;

	dev->tbusy = 1;
	dev->start = 0;

	/* Flush the Tx and disable Rx here. */
	lp->addr_mode = CMR2h_OFF;
	write_reg_high(ioaddr, CMR2, CMR2h_OFF);

	/* Free the IRQ line. */
	outb(0x00, ioaddr + PAR_CONTROL);
	free_irq(dev->irq, dev);

	/* Leave the hardware in a reset state. */
    write_reg_high(ioaddr, CMR1, CMR1h_RESET);

	return 0;
}

/* Get the current statistics.	This may be called with the card open or
   closed. */
static struct net_device_stats *net_get_stats(struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	return &lp->stats;
}

/*
 *	Set or clear the multicast filter for this adapter.
 */
 
static void set_multicast_list(struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	short ioaddr = dev->base_addr;
	int num_addrs=dev->mc_count;
	
	if(dev->flags&(IFF_ALLMULTI|IFF_PROMISC))
		num_addrs=1;
	/*
	 *	We must make the kernel realise we had to move
	 *	into promisc mode or we start all out war on
	 *	the cable. - AC
	 */
	if(num_addrs)
		dev->flags|=IFF_PROMISC;		
	lp->addr_mode = num_addrs ? CMR2h_PROMISC : CMR2h_Normal;
	write_reg_high(ioaddr, CMR2, lp->addr_mode);
}

/*
 * Local variables:
 *  compile-command: "gcc -D__KERNEL__ -I/usr/src/linux/net/inet -Wall -Wstrict-prototypes -O6 -m486 -c atp.c"
 *  version-control: t
 *  kept-new-versions: 5
 *  tab-width: 4
 * End:
 */