aboutsummaryrefslogtreecommitdiff
path: root/drivers/net/atp.c
blob: a841feb5df20982d1eb440d136468cdf6c9e3338 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
/* atp.c: Attached (pocket) ethernet adapter driver for linux. */
/*
	This is a driver for commonly OEM pocket (parallel port)
	ethernet adapters based on the Realtek RTL8002 and RTL8012 chips.

	Written 1993-2000 by Donald Becker.

	This software may be used and distributed according to the terms of
	the GNU General Public License (GPL), incorporated herein by reference.
	Drivers based on or derived from this code fall under the GPL and must
	retain the authorship, copyright and license notice.  This file is not
	a complete program and may only be used when the entire operating
	system is licensed under the GPL.

	Copyright 1993 United States Government as represented by the Director,
	National Security Agency.  Copyright 1994-2000 retained by the original
	author, Donald Becker. The timer-based reset code was supplied in 1995
	by Bill Carlson, wwc@super.org.

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

	Support information and updates available at
	http://www.scyld.com/network/atp.html


	Modular support/softnet added by Alan Cox.
	_bit abuse fixed up by Alan Cox

*/

static const char version[] =
"atp.c:v1.09=ac 2002/10/01 Donald Becker <becker@scyld.com>\n";

/* The user-configurable values.
   These may be modified when a driver module is loaded.*/

static int debug = 1; 			/* 1 normal messages, 0 quiet .. 7 verbose. */
#define net_debug debug

/* Maximum events (Rx packets, etc.) to handle at each interrupt. */
static int max_interrupt_work = 15;

#define NUM_UNITS 2
/* The standard set of ISA module parameters. */
static int io[NUM_UNITS];
static int irq[NUM_UNITS];
static int xcvr[NUM_UNITS]; 			/* The data transfer mode. */

/* Operational parameters that are set at compile time. */

/* Time in jiffies before concluding the transmitter is hung. */
#define TX_TIMEOUT  (400*HZ/1000)

/*
	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.

	In 1997 Realtek made available the documentation for the second generation
	RTL8012 chip, which has lead to several driver improvements.
	  http://www.realtek.com.tw/cn/cn.html

					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.

	Correction: the controller has two banks of 16 registers.  The second
	bank contains only the multicast filter table (now used) and the EEPROM
	access registers.

	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/module.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/crc32.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/bitops.h>

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

#include "atp.h"

MODULE_AUTHOR("Donald Becker <becker@scyld.com>");
MODULE_DESCRIPTION("RealTek RTL8002/8012 parallel port Ethernet driver");
MODULE_LICENSE("GPL");

module_param(max_interrupt_work, int, 0);
module_param(debug, int, 0);
module_param_array(io, int, NULL, 0);
module_param_array(irq, int, NULL, 0);
module_param_array(xcvr, int, NULL, 0);
MODULE_PARM_DESC(max_interrupt_work, "ATP maximum events handled per interrupt");
MODULE_PARM_DESC(debug, "ATP debug level (0-7)");
MODULE_PARM_DESC(io, "ATP I/O base address(es)");
MODULE_PARM_DESC(irq, "ATP IRQ number(s)");
MODULE_PARM_DESC(xcvr, "ATP transceiver(s) (0=internal, 1=external)");

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

/* Sequence to switch an 8012 from printer mux to ethernet mode. */
static char mux_8012[] = { 0xff, 0xf7, 0xff, 0xfb, 0xf3, 0xfb, 0xff, 0xf7,};

struct net_local {
    spinlock_t lock;
    struct net_device *next_module;
    struct timer_list timer;	/* Media selection timer. */
    long last_rx_time;		/* Last Rx, in jiffies, to handle Rx hang. */
    int saved_tx_size;
    unsigned int tx_unit_busy:1;
    unsigned char re_tx,	/* Number of packet retransmissions. */
		addr_mode,		/* Current Rx filter e.g. promiscuous, etc. */
		pac_cnt_in_tx_buf,
		chip_type;
};

/* 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);
#endif

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

static int atp_probe1(long ioaddr);
static void get_node_ID(struct net_device *dev);
static unsigned short eeprom_op(long ioaddr, unsigned int cmd);
static int net_open(struct net_device *dev);
static void hardware_init(struct net_device *dev);
static void write_packet(long ioaddr, int length, unsigned char *packet, int pad, int mode);
static void trigger_send(long ioaddr, int length);
static netdev_tx_t atp_send_packet(struct sk_buff *skb,
				   struct net_device *dev);
static irqreturn_t atp_interrupt(int irq, void *dev_id);
static void net_rx(struct net_device *dev);
static void read_block(long ioaddr, int length, unsigned char *buffer, int data_mode);
static int net_close(struct net_device *dev);
static void set_rx_mode(struct net_device *dev);
static void tx_timeout(struct net_device *dev);


/* A list of all installed ATP devices, for removing the driver module. */
static struct net_device *root_atp_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).

   FIXME: we should use the parport layer for this
   */
static int __init atp_init(void)
{
	int *port, ports[] = {0x378, 0x278, 0x3bc, 0};
	int base_addr = io[0];

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

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

	return -ENODEV;
}

static const struct net_device_ops atp_netdev_ops = {
	.ndo_open		= net_open,
	.ndo_stop		= net_close,
	.ndo_start_xmit		= atp_send_packet,
	.ndo_set_multicast_list = set_rx_mode,
	.ndo_tx_timeout		= tx_timeout,
	.ndo_change_mtu		= eth_change_mtu,
	.ndo_set_mac_address 	= eth_mac_addr,
	.ndo_validate_addr	= eth_validate_addr,
};

static int __init atp_probe1(long ioaddr)
{
	struct net_device *dev = NULL;
	struct net_local *lp;
	int saved_ctrl_reg, status, i;
	int res;

	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);
	if (net_debug > 3)
		printk("atp: Control register was %#2.2x.\n", saved_ctrl_reg);
	/* IRQEN=0, SLCTB=high INITB=high, AUTOFDB=high, STBB=high. */
	outb(0x04, ioaddr + PAR_CONTROL);
#ifndef final_version
	if (net_debug > 3) {
		/* Turn off the printer multiplexer on the 8012. */
		for (i = 0; i < 8; i++)
			outb(mux_8012[i], ioaddr + PAR_DATA);
		write_reg(ioaddr, MODSEL, 0x00);
		printk("atp: Registers are ");
		for (i = 0; i < 32; i++)
			printk(" %2.2x", read_nibble(ioaddr, i));
		printk(".\n");
	}
#endif
	/* Turn off the printer multiplexer on the 8012. */
	for (i = 0; i < 8; i++)
		outb(mux_8012[i], ioaddr + PAR_DATA);
	write_reg_high(ioaddr, CMR1, CMR1h_RESET);
	/* udelay() here? */
	status = read_nibble(ioaddr, CMR1);

	if (net_debug > 3) {
		printk(KERN_DEBUG "atp: Status nibble was %#2.2x..", status);
		for (i = 0; i < 32; i++)
			printk(" %2.2x", read_nibble(ioaddr, i));
		printk("\n");
	}

	if ((status & 0x78) != 0x08) {
		/* The pocket adapter probe failed, restore the control register. */
		outb(saved_ctrl_reg, ioaddr + PAR_CONTROL);
		return -ENODEV;
	}
	status = read_nibble(ioaddr, CMR2_h);
	if ((status & 0x78) != 0x10) {
		outb(saved_ctrl_reg, ioaddr + PAR_CONTROL);
		return -ENODEV;
	}

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

	/* 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 (irq[0])
		dev->irq = irq[0];
	else 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);

#ifndef MODULE
	if (net_debug)
		printk(KERN_INFO "%s", version);
#endif

	printk(KERN_NOTICE "%s: Pocket adapter found at %#3lx, IRQ %d, "
	       "SAPROM %pM.\n",
	       dev->name, dev->base_addr, dev->irq, dev->dev_addr);

	/* Reset the ethernet hardware and activate the printer pass-through. */
	write_reg_high(ioaddr, CMR1, CMR1h_RESET | CMR1h_MUX);

	lp = netdev_priv(dev);
	lp->chip_type = RTL8002;
	lp->addr_mode = CMR2h_Normal;
	spin_lock_init(&lp->lock);

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

	dev->netdev_ops 	= &atp_netdev_ops;
	dev->watchdog_timeo	= TX_TIMEOUT;

	res = register_netdev(dev);
	if (res) {
		free_netdev(dev);
		return res;
	}

	lp->next_module = root_atp_dev;
	root_atp_dev = dev;

	return 0;
}

/* Read the station address PROM, usually a word-wide EEPROM. */
static void __init get_node_ID(struct net_device *dev)
{
	long 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++)
		((__be16 *)dev->dev_addr)[i] =
			cpu_to_be16(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
 */

static unsigned short __init eeprom_op(long ioaddr, u32 cmd)
{
	unsigned eedata_out = 0;
	int num_bits = EE_CMD_SIZE;

	while (--num_bits >= 0) {
		char outval = (cmd & (1<<num_bits)) ? EE_DATA_WRITE : 0;
		write_reg_high(ioaddr, PROM_CMD, outval | EE_CLK_LOW);
		write_reg_high(ioaddr, PROM_CMD, outval | EE_CLK_HIGH);
		eedata_out <<= 1;
		if (read_nibble(ioaddr, PROM_DATA) & EE_DATA_READ)
			eedata_out++;
	}
	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 private entry then it wasn't
   probed for at boot-time, and we need to probe for it again.
   */
static int net_open(struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	int ret;

	/* 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. */
	ret = request_irq(dev->irq, atp_interrupt, 0, dev->name, dev);
	if (ret)
		return ret;

	hardware_init(dev);

	init_timer(&lp->timer);
	lp->timer.expires = jiffies + TIMED_CHECKER;
	lp->timer.data = (unsigned long)dev;
	lp->timer.function = &atp_timed_checker;    /* timer handler */
	add_timer(&lp->timer);

	netif_start_queue(dev);
	return 0;
}

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

	/* Turn off the printer multiplexer on the 8012. */
	for (i = 0; i < 8; i++)
		outb(mux_8012[i], ioaddr + PAR_DATA);
	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(KERN_DEBUG "%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;
}

static void trigger_send(long 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(long ioaddr, int length, unsigned char *packet, int pad_len, int data_mode)
{
    if (length & 1)
    {
    	length++;
    	pad_len++;
    }

    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 > pad_len) ;
		do {
			write_byte_mode0(ioaddr, 0);
		} 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 > pad_len)
			write_byte_mode1(ioaddr, *packet++);
		while (--length > 0)
			write_byte_mode1(ioaddr, 0);
    }
    /* Terminate the Tx frame.  End of write: ECB. */
    outb(0xff, ioaddr + PAR_DATA);
    outb(Ctrl_HNibWrite | Ctrl_SelData | Ctrl_IRQEN, ioaddr + PAR_CONTROL);
}

static void tx_timeout(struct net_device *dev)
{
	long ioaddr = dev->base_addr;

	printk(KERN_WARNING "%s: Transmit timed out, %s?\n", dev->name,
		   inb(ioaddr + PAR_CONTROL) & 0x10 ? "network cable problem"
		   :  "IRQ conflict");
	dev->stats.tx_errors++;
	/* Try to restart the adapter. */
	hardware_init(dev);
	dev->trans_start = jiffies;
	netif_wake_queue(dev);
	dev->stats.tx_errors++;
}

static netdev_tx_t atp_send_packet(struct sk_buff *skb,
				   struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	long ioaddr = dev->base_addr;
	int length;
	unsigned long flags;

	length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;

	netif_stop_queue(dev);

	/* Disable interrupts by writing 0x00 to the Interrupt Mask Register.
	   This sequence must not be interrupted by an incoming packet. */

	spin_lock_irqsave(&lp->lock, flags);
	write_reg(ioaddr, IMR, 0);
	write_reg_high(ioaddr, IMR, 0);
	spin_unlock_irqrestore(&lp->lock, flags);

	write_packet(ioaddr, length, skb->data, length-skb->len, 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;
	/* Re-enable the LPT interrupts. */
	write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
	write_reg_high(ioaddr, IMR, ISRh_RxErr);

	dev->trans_start = jiffies;
	dev_kfree_skb (skb);
	return NETDEV_TX_OK;
}


/* The typical workload of the driver:
   Handle the network interface interrupts. */
static irqreturn_t atp_interrupt(int irq, void *dev_instance)
{
	struct net_device *dev = dev_instance;
	struct net_local *lp;
	long ioaddr;
	static int num_tx_since_rx;
	int boguscount = max_interrupt_work;
	int handled = 0;

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

	spin_lock(&lp->lock);

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

		if (status & (ISR_RxOK<<3)) {
			handled = 1;
			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. */
					dev->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);
					num_tx_since_rx = 0;
				} else
					break;
			} while (--boguscount > 0);
		} else if (status & ((ISR_TxErr + ISR_TxOK)<<3)) {
			handled = 1;
			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)) {
				dev->stats.collisions++;
				if (++lp->re_tx > 15) {
					dev->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. */
				dev->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;
				netif_wake_queue(dev);	/* Inform upper layers. */
			}
			num_tx_since_rx++;
		} else if (num_tx_since_rx > 8 &&
			   time_after(jiffies, dev->last_rx + HZ)) {
			if (net_debug > 2)
				printk(KERN_DEBUG "%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);
			dev->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]);
#if 0 && defined(TIMED_CHECKER)
		mod_timer(&lp->timer, jiffies + TIMED_CHECKER);
#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? */

	spin_unlock(&lp->lock);

	if (net_debug > 5) printk("exiting interrupt.\n");
	return IRQ_RETVAL(handled);
}

#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 data)
{
	struct net_device *dev = (struct net_device *)data;
	long ioaddr = dev->base_addr;
	struct net_local *lp = netdev_priv(dev);
	int tickssofar = jiffies - lp->last_rx_time;
	int i;

	spin_lock(&lp->lock);
	if (tickssofar > 2*HZ) {
#if 1
		for (i = 0; i < 6; i++)
			write_reg_byte(ioaddr, PAR0 + i, dev->dev_addr[i]);
		lp->last_rx_time = jiffies;
#else
		for (i = 0; i < 6; i++)
			if (read_cmd_byte(ioaddr, PAR0 + i) != atp_timed_dev->dev_addr[i])
				{
			struct net_local *lp = netdev_priv(atp_timed_dev);
			write_reg_byte(ioaddr, PAR0 + i, atp_timed_dev->dev_addr[i]);
			if (i == 2)
			  dev->stats.tx_errors++;
			else if (i == 3)
			  dev->stats.tx_dropped++;
			else if (i == 4)
			  dev->stats.collisions++;
			else
			  dev->stats.rx_errors++;
		  }
#endif
	}
	spin_unlock(&lp->lock);
	lp->timer.expires = jiffies + TIMED_CHECKER;
	add_timer(&lp->timer);
}
#endif

/* We have a good packet(s), get it/them out of the buffers. */
static void net_rx(struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	long ioaddr = dev->base_addr;
	struct rx_header rx_head;

	/* 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(KERN_DEBUG " 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) {
		dev->stats.rx_errors++;
		if (rx_head.rx_status & 0x0004) dev->stats.rx_frame_errors++;
		else if (rx_head.rx_status & 0x0002) dev->stats.rx_crc_errors++;
		if (net_debug > 3)
			printk(KERN_DEBUG "%s: Unknown ATP Rx error %04x.\n",
				   dev->name, rx_head.rx_status);
		if  (rx_head.rx_status & 0x0020) {
			dev->stats.rx_fifo_errors++;
			write_reg_high(ioaddr, CMR1, CMR1h_TxENABLE);
			write_reg_high(ioaddr, CMR1, CMR1h_RxENABLE | CMR1h_TxENABLE);
		} else if (rx_head.rx_status & 0x0050)
			hardware_init(dev);
		return;
	} else {
		/* Malloc up new buffer. The "-4" omits the FCS (CRC). */
		int pkt_len = (rx_head.rx_count & 0x7ff) - 4;
		struct sk_buff *skb;

		skb = dev_alloc_skb(pkt_len + 2);
		if (skb == NULL) {
			printk(KERN_ERR "%s: Memory squeeze, dropping packet.\n",
				   dev->name);
			dev->stats.rx_dropped++;
			goto done;
		}

		skb_reserve(skb, 2);	/* Align IP on 16 byte boundaries */
		read_block(ioaddr, pkt_len, skb_put(skb,pkt_len), dev->if_port);
		skb->protocol = eth_type_trans(skb, dev);
		netif_rx(skb);
		dev->last_rx = jiffies;
		dev->stats.rx_packets++;
		dev->stats.rx_bytes += pkt_len;
	}
 done:
	write_reg(ioaddr, CMR1, CMR1_NextPkt);
	lp->last_rx_time = jiffies;
	return;
}

static void read_block(long 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 net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	long ioaddr = dev->base_addr;

	netif_stop_queue(dev);

	del_timer_sync(&lp->timer);

	/* 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);

	/* Reset the ethernet hardware and activate the printer pass-through. */
	write_reg_high(ioaddr, CMR1, CMR1h_RESET | CMR1h_MUX);
	return 0;
}

/*
 *	Set or clear the multicast filter for this adapter.
 */

static void set_rx_mode_8002(struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	long ioaddr = dev->base_addr;

	if (!netdev_mc_empty(dev) || (dev->flags & (IFF_ALLMULTI|IFF_PROMISC)))
		lp->addr_mode = CMR2h_PROMISC;
	else
		lp->addr_mode = CMR2h_Normal;
	write_reg_high(ioaddr, CMR2, lp->addr_mode);
}

static void set_rx_mode_8012(struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);
	long ioaddr = dev->base_addr;
	unsigned char new_mode, mc_filter[8]; /* Multicast hash filter */
	int i;

	if (dev->flags & IFF_PROMISC) {			/* Set promiscuous. */
		new_mode = CMR2h_PROMISC;
	} else if ((netdev_mc_count(dev) > 1000) ||
		   (dev->flags & IFF_ALLMULTI)) {
		/* Too many to filter perfectly -- accept all multicasts. */
		memset(mc_filter, 0xff, sizeof(mc_filter));
		new_mode = CMR2h_Normal;
	} else {
		struct dev_mc_list *mclist;

		memset(mc_filter, 0, sizeof(mc_filter));
		for (i = 0, mclist = dev->mc_list; mclist && i < netdev_mc_count(dev);
			 i++, mclist = mclist->next)
		{
			int filterbit = ether_crc_le(ETH_ALEN, mclist->dmi_addr) & 0x3f;
			mc_filter[filterbit >> 5] |= 1 << (filterbit & 31);
		}
		new_mode = CMR2h_Normal;
	}
	lp->addr_mode = new_mode;
    write_reg(ioaddr, CMR2, CMR2_IRQOUT | 0x04); /* Switch to page 1. */
    for (i = 0; i < 8; i++)
		write_reg_byte(ioaddr, i, mc_filter[i]);
	if (net_debug > 2 || 1) {
		lp->addr_mode = 1;
		printk(KERN_DEBUG "%s: Mode %d, setting multicast filter to",
			   dev->name, lp->addr_mode);
		for (i = 0; i < 8; i++)
			printk(" %2.2x", mc_filter[i]);
		printk(".\n");
	}

	write_reg_high(ioaddr, CMR2, lp->addr_mode);
    write_reg(ioaddr, CMR2, CMR2_IRQOUT); /* Switch back to page 0 */
}

static void set_rx_mode(struct net_device *dev)
{
	struct net_local *lp = netdev_priv(dev);

	if (lp->chip_type == RTL8002)
		return set_rx_mode_8002(dev);
	else
		return set_rx_mode_8012(dev);
}


static int __init atp_init_module(void) {
	if (debug)					/* Emit version even if no cards detected. */
		printk(KERN_INFO "%s", version);
	return atp_init();
}

static void __exit atp_cleanup_module(void) {
	struct net_device *next_dev;

	while (root_atp_dev) {
		struct net_local *atp_local = netdev_priv(root_atp_dev);
		next_dev = atp_local->next_module;
		unregister_netdev(root_atp_dev);
		/* No need to release_region(), since we never snarf it. */
		free_netdev(root_atp_dev);
		root_atp_dev = next_dev;
	}
}

module_init(atp_init_module);
module_exit(atp_cleanup_module);