Free Electrons

Embedded Linux Experts

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 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
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
/*
 *	de620.c $Revision: 1.40 $ BETA
 *
 *
 *	Linux driver for the D-Link DE-620 Ethernet pocket adapter.
 *
 *	Portions (C) Copyright 1993, 1994 by Bjorn Ekwall <bj0rn@blox.se>
 *
 *	Based on adapter information gathered from DOS packetdriver
 *	sources from D-Link Inc:  (Special thanks to Henry Ngai of D-Link.)
 *		Portions (C) Copyright D-Link SYSTEM Inc. 1991, 1992
 *		Copyright, 1988, Russell Nelson, Crynwr Software
 *
 *	Adapted to the sample network driver core for linux,
 *	written by: Donald Becker <becker@super.org>
 *		(Now at <becker@scyld.com>)
 *
 *	Valuable assistance from:
 *		J. Joshua Kopper <kopper@rtsg.mot.com>
 *		Olav Kvittem <Olav.Kvittem@uninett.no>
 *		Germano Caronni <caronni@nessie.cs.id.ethz.ch>
 *		Jeremy Fitzhardinge <jeremy@suite.sw.oz.au>
 *
 *****************************************************************************/
/*
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 2, or (at your option)
 *	any later version.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with this program; if not, write to the Free Software
 *	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *****************************************************************************/
static const char version[] =
	"de620.c: $Revision: 1.40 $,  Bjorn Ekwall <bj0rn@blox.se>\n";

/***********************************************************************
 *
 * "Tuning" section.
 *
 * Compile-time options: (see below for descriptions)
 * -DDE620_IO=0x378	(lpt1)
 * -DDE620_IRQ=7	(lpt1)
 * -DDE602_DEBUG=...
 * -DSHUTDOWN_WHEN_LOST
 * -DCOUNT_LOOPS
 * -DLOWSPEED
 * -DREAD_DELAY
 * -DWRITE_DELAY
 */

/*
 * This driver assumes that the printer port is a "normal",
 * dumb, uni-directional port!
 * If your port is "fancy" in any way, please try to set it to "normal"
 * with your BIOS setup.  I have no access to machines with bi-directional
 * ports, so I can't test such a driver :-(
 * (Yes, I _know_ it is possible to use DE620 with bidirectional ports...)
 *
 * There are some clones of DE620 out there, with different names.
 * If the current driver does not recognize a clone, try to change
 * the following #define to:
 *
 * #define DE620_CLONE 1
 */
#define DE620_CLONE 0

/*
 * If the adapter has problems with high speeds, enable this #define
 * otherwise full printerport speed will be attempted.
 *
 * You can tune the READ_DELAY/WRITE_DELAY below if you enable LOWSPEED
 *
#define LOWSPEED
 */

#ifndef READ_DELAY
#define READ_DELAY 100	/* adapter internal read delay in 100ns units */
#endif

#ifndef WRITE_DELAY
#define WRITE_DELAY 100	/* adapter internal write delay in 100ns units */
#endif

/*
 * Enable this #define if you want the adapter to do a "ifconfig down" on
 * itself when we have detected that something is possibly wrong with it.
 * The default behaviour is to retry with "adapter_init()" until success.
 * This should be used for debugging purposes only.
 *
#define SHUTDOWN_WHEN_LOST
 */

/*
 * Enable debugging by "-DDE620_DEBUG=3" when compiling,
 * OR by enabling the following #define
 *
 * use 0 for production, 1 for verification, >2 for debug
 *
#define DE620_DEBUG 3
 */

#ifdef LOWSPEED
/*
 * Enable this #define if you want to see debugging output that show how long
 * we have to wait before the DE-620 is ready for the next read/write/command.
 *
#define COUNT_LOOPS
 */
#endif

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>

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

/* Constant definitions for the DE-620 registers, commands and bits */
#include "de620.h"

typedef unsigned char byte;

/*******************************************************
 *                                                     *
 * Definition of D-Link DE-620 Ethernet Pocket adapter *
 * See also "de620.h"                                  *
 *                                                     *
 *******************************************************/
#ifndef DE620_IO /* Compile-time configurable */
#define DE620_IO 0x378
#endif

#ifndef DE620_IRQ /* Compile-time configurable */
#define DE620_IRQ	7
#endif

#define DATA_PORT	(dev->base_addr)
#define STATUS_PORT	(dev->base_addr + 1)
#define COMMAND_PORT	(dev->base_addr + 2)

#define RUNT 60		/* Too small Ethernet packet */
#define GIANT 1514	/* largest legal size packet, no fcs */

#ifdef DE620_DEBUG /* Compile-time configurable */
#define PRINTK(x) if (de620_debug >= 2) printk x
#else
#define DE620_DEBUG 0
#define PRINTK(x) /**/
#endif


/*
 * Force media with insmod:
 *	insmod de620.o bnc=1
 * or
 *	insmod de620.o utp=1
 *
 * Force io and/or irq with insmod:
 *	insmod de620.o io=0x378 irq=7
 *
 * Make a clone skip the Ethernet-address range check:
 *	insmod de620.o clone=1
 */
static int bnc;
static int utp;
static int io  = DE620_IO;
static int irq = DE620_IRQ;
static int clone = DE620_CLONE;

static unsigned int de620_debug = DE620_DEBUG;

static spinlock_t de620_lock;

module_param(bnc, int, 0);
module_param(utp, int, 0);
module_param(io, int, 0);
module_param(irq, int, 0);
module_param(clone, int, 0);
module_param(de620_debug, int, 0);
MODULE_PARM_DESC(bnc, "DE-620 set BNC medium (0-1)");
MODULE_PARM_DESC(utp, "DE-620 set UTP medium (0-1)");
MODULE_PARM_DESC(io, "DE-620 I/O base address,required");
MODULE_PARM_DESC(irq, "DE-620 IRQ number,required");
MODULE_PARM_DESC(clone, "Check also for non-D-Link DE-620 clones (0-1)");
MODULE_PARM_DESC(de620_debug, "DE-620 debug level (0-2)");

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

/*
 * Routines used internally. (See also "convenience macros.. below")
 */

/* Put in the device structure. */
static int	de620_open(struct net_device *);
static int	de620_close(struct net_device *);
static struct	net_device_stats *get_stats(struct net_device *);
static void	de620_set_multicast_list(struct net_device *);
static int	de620_start_xmit(struct sk_buff *, struct net_device *);

/* Dispatch from interrupts. */
static irqreturn_t de620_interrupt(int, void *, struct pt_regs *);
static int	de620_rx_intr(struct net_device *);

/* Initialization */
static int	adapter_init(struct net_device *);
static int	read_eeprom(struct net_device *);


/*
 * D-Link driver variables:
 */
#define SCR_DEF NIBBLEMODE |INTON | SLEEP | AUTOTX
#define	TCR_DEF RXPB			/* not used: | TXSUCINT | T16INT */
#define DE620_RX_START_PAGE 12		/* 12 pages (=3k) reserved for tx */
#define DEF_NIC_CMD IRQEN | ICEN | DS1

static volatile byte	NIC_Cmd;
static volatile byte	next_rx_page;
static byte		first_rx_page;
static byte		last_rx_page;
static byte		EIPRegister;

static struct nic {
	byte	NodeID[6];
	byte	RAM_Size;
	byte	Model;
	byte	Media;
	byte	SCR;
} nic_data;

/**********************************************************
 *                                                        *
 * Convenience macros/functions for D-Link DE-620 adapter *
 *                                                        *
 **********************************************************/
#define de620_tx_buffs(dd) (inb(STATUS_PORT) & (TXBF0 | TXBF1))
#define de620_flip_ds(dd) NIC_Cmd ^= DS0 | DS1; outb(NIC_Cmd, COMMAND_PORT);

/* Check for ready-status, and return a nibble (high 4 bits) for data input */
#ifdef COUNT_LOOPS
static int tot_cnt;
#endif
static inline byte
de620_ready(struct net_device *dev)
{
	byte value;
	register short int cnt = 0;

	while ((((value = inb(STATUS_PORT)) & READY) == 0) && (cnt <= 1000))
		++cnt;

#ifdef COUNT_LOOPS
	tot_cnt += cnt;
#endif
	return value & 0xf0; /* nibble */
}

static inline void
de620_send_command(struct net_device *dev, byte cmd)
{
	de620_ready(dev);
	if (cmd == W_DUMMY)
		outb(NIC_Cmd, COMMAND_PORT);

	outb(cmd, DATA_PORT);

	outb(NIC_Cmd ^ CS0, COMMAND_PORT);
	de620_ready(dev);
	outb(NIC_Cmd, COMMAND_PORT);
}

static inline void
de620_put_byte(struct net_device *dev, byte value)
{
	/* The de620_ready() makes 7 loops, on the average, on a DX2/66 */
	de620_ready(dev);
	outb(value, DATA_PORT);
	de620_flip_ds(dev);
}

static inline byte
de620_read_byte(struct net_device *dev)
{
	byte value;

	/* The de620_ready() makes 7 loops, on the average, on a DX2/66 */
	value = de620_ready(dev); /* High nibble */
	de620_flip_ds(dev);
	value |= de620_ready(dev) >> 4; /* Low nibble */
	return value;
}

static inline void
de620_write_block(struct net_device *dev, byte *buffer, int count, int pad)
{
#ifndef LOWSPEED
	byte uflip = NIC_Cmd ^ (DS0 | DS1);
	byte dflip = NIC_Cmd;
#else /* LOWSPEED */
#ifdef COUNT_LOOPS
	int bytes = count;
#endif /* COUNT_LOOPS */
#endif /* LOWSPEED */

#ifdef LOWSPEED
#ifdef COUNT_LOOPS
	tot_cnt = 0;
#endif /* COUNT_LOOPS */
	/* No further optimization useful, the limit is in the adapter. */
	for ( ; count > 0; --count, ++buffer) {
		de620_put_byte(dev,*buffer);
	}
	for ( count = pad ; count > 0; --count, ++buffer) {
		de620_put_byte(dev, 0);
	}
	de620_send_command(dev,W_DUMMY);
#ifdef COUNT_LOOPS
	/* trial debug output: loops per byte in de620_ready() */
	printk("WRITE(%d)\n", tot_cnt/((bytes?bytes:1)));
#endif /* COUNT_LOOPS */
#else /* not LOWSPEED */
	for ( ; count > 0; count -=2) {
		outb(*buffer++, DATA_PORT);
		outb(uflip, COMMAND_PORT);
		outb(*buffer++, DATA_PORT);
		outb(dflip, COMMAND_PORT);
	}
	de620_send_command(dev,W_DUMMY);
#endif /* LOWSPEED */
}

static inline void
de620_read_block(struct net_device *dev, byte *data, int count)
{
#ifndef LOWSPEED
	byte value;
	byte uflip = NIC_Cmd ^ (DS0 | DS1);
	byte dflip = NIC_Cmd;
#else /* LOWSPEED */
#ifdef COUNT_LOOPS
	int bytes = count;

	tot_cnt = 0;
#endif /* COUNT_LOOPS */
#endif /* LOWSPEED */

#ifdef LOWSPEED
	/* No further optimization useful, the limit is in the adapter. */
	while (count-- > 0) {
		*data++ = de620_read_byte(dev);
		de620_flip_ds(dev);
	}
#ifdef COUNT_LOOPS
	/* trial debug output: loops per byte in de620_ready() */
	printk("READ(%d)\n", tot_cnt/(2*(bytes?bytes:1)));
#endif /* COUNT_LOOPS */
#else /* not LOWSPEED */
	while (count-- > 0) {
		value = inb(STATUS_PORT) & 0xf0; /* High nibble */
		outb(uflip, COMMAND_PORT);
		*data++ = value | inb(STATUS_PORT) >> 4; /* Low nibble */
		outb(dflip , COMMAND_PORT);
	}
#endif /* LOWSPEED */
}

static inline void
de620_set_delay(struct net_device *dev)
{
	de620_ready(dev);
	outb(W_DFR, DATA_PORT);
	outb(NIC_Cmd ^ CS0, COMMAND_PORT);

	de620_ready(dev);
#ifdef LOWSPEED
	outb(WRITE_DELAY, DATA_PORT);
#else
	outb(0, DATA_PORT);
#endif
	de620_flip_ds(dev);

	de620_ready(dev);
#ifdef LOWSPEED
	outb(READ_DELAY, DATA_PORT);
#else
	outb(0, DATA_PORT);
#endif
	de620_flip_ds(dev);
}

static inline void
de620_set_register(struct net_device *dev, byte reg, byte value)
{
	de620_ready(dev);
	outb(reg, DATA_PORT);
	outb(NIC_Cmd ^ CS0, COMMAND_PORT);

	de620_put_byte(dev, value);
}

static inline byte
de620_get_register(struct net_device *dev, byte reg)
{
	byte value;

	de620_send_command(dev,reg);
	value = de620_read_byte(dev);
	de620_send_command(dev,W_DUMMY);

	return value;
}

/*********************************************************************
 *
 * Open/initialize the board.
 *
 * This routine should set everything up anew at each open, even
 * registers that "should" only need to be set once at boot, so that
 * there is a non-reboot way to recover if something goes wrong.
 *
 */
static int de620_open(struct net_device *dev)
{
	int ret = request_irq(dev->irq, de620_interrupt, 0, dev->name, dev);
	if (ret) {
		printk (KERN_ERR "%s: unable to get IRQ %d\n", dev->name, dev->irq);
		return ret;
	}

	if (adapter_init(dev)) {
		ret = -EIO;
		goto out_free_irq;
	}

	netif_start_queue(dev);
	return 0;

out_free_irq:
	free_irq(dev->irq, dev);
	return ret;
}

/************************************************
 *
 * The inverse routine to de620_open().
 *
 */

static int de620_close(struct net_device *dev)
{
	netif_stop_queue(dev);
	/* disable recv */
	de620_set_register(dev, W_TCR, RXOFF);
	free_irq(dev->irq, dev);
	return 0;
}

/*********************************************
 *
 * Return current statistics
 *
 */
static struct net_device_stats *get_stats(struct net_device *dev)
{
	return (struct net_device_stats *)(dev->priv);
}

/*********************************************
 *
 * Set or clear the multicast filter for this adaptor.
 * (no real multicast implemented for the DE-620, but she can be promiscuous...)
 *
 */

static void de620_set_multicast_list(struct net_device *dev)
{
	if (dev->mc_count || dev->flags&(IFF_ALLMULTI|IFF_PROMISC))
	{ /* Enable promiscuous mode */
		/*
		 *	We must make the kernel realise we had to move
		 *	into promisc mode or we start all out war on
		 *	the cable. - AC
		 */
		dev->flags|=IFF_PROMISC;

		de620_set_register(dev, W_TCR, (TCR_DEF & ~RXPBM) | RXALL);
	}
	else
	{ /* Disable promiscuous mode, use normal mode */
		de620_set_register(dev, W_TCR, TCR_DEF);
	}
}

/*******************************************************
 *	
 * Handle timeouts on transmit
 */
 
static void de620_timeout(struct net_device *dev)
{
	printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name, "network cable problem");
	/* Restart the adapter. */
	if (!adapter_init(dev)) /* maybe close it */
		netif_wake_queue(dev);
}

/*******************************************************
 *
 * Copy a buffer to the adapter transmit page memory.
 * Start sending.
 */
static int de620_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	unsigned long flags;
	int len;
	byte *buffer = skb->data;
	byte using_txbuf;

	using_txbuf = de620_tx_buffs(dev); /* Peek at the adapter */
	
	netif_stop_queue(dev);
	

	if ((len = skb->len) < RUNT)
		len = RUNT;
	if (len & 1) /* send an even number of bytes */
		++len;

	/* Start real output */

	spin_lock_irqsave(&de620_lock, flags)
	PRINTK(("de620_start_xmit: len=%d, bufs 0x%02x\n",
		(int)skb->len, using_txbuf));

	/* select a free tx buffer. if there is one... */
	switch (using_txbuf) {
	default: /* both are free: use TXBF0 */
	case TXBF1: /* use TXBF0 */
		de620_send_command(dev,W_CR | RW0);
		using_txbuf |= TXBF0;
		break;

	case TXBF0: /* use TXBF1 */
		de620_send_command(dev,W_CR | RW1);
		using_txbuf |= TXBF1;
		break;

	case (TXBF0 | TXBF1): /* NONE!!! */
		printk(KERN_WARNING "%s: No tx-buffer available!\n", dev->name);
		spin_unlock_irqrestore(&de620_lock, flags);
		return 1;
	}
	de620_write_block(dev, buffer, skb->len, len-skb->len);

	dev->trans_start = jiffies;
	if(!(using_txbuf == (TXBF0 | TXBF1)))
		netif_wake_queue(dev);

	((struct net_device_stats *)(dev->priv))->tx_packets++;
	spin_unlock_irqrestore(&de620_lock, flags);
	dev_kfree_skb (skb);
	return 0;
}

/*****************************************************
 *
 * Handle the network interface interrupts.
 *
 */
static irqreturn_t
de620_interrupt(int irq_in, void *dev_id, struct pt_regs *regs)
{
	struct net_device *dev = dev_id;
	byte irq_status;
	int bogus_count = 0;
	int again = 0;

	spin_lock(&de620_lock);
	
	/* Read the status register (_not_ the status port) */
	irq_status = de620_get_register(dev, R_STS);

	PRINTK(("de620_interrupt (%2.2X)\n", irq_status));

	if (irq_status & RXGOOD) {
		do {
			again = de620_rx_intr(dev);
			PRINTK(("again=%d\n", again));
		}
		while (again && (++bogus_count < 100));
	}

	if(de620_tx_buffs(dev) != (TXBF0 | TXBF1))
		netif_wake_queue(dev);
		
	spin_unlock(&de620_lock);
	return IRQ_HANDLED;
}

/**************************************
 *
 * Get a packet from the adapter
 *
 * Send it "upstairs"
 *
 */
static int de620_rx_intr(struct net_device *dev)
{
	struct header_buf {
		byte		status;
		byte		Rx_NextPage;
		unsigned short	Rx_ByteCount;
	} header_buf;
	struct sk_buff *skb;
	int size;
	byte *buffer;
	byte pagelink;
	byte curr_page;

	PRINTK(("de620_rx_intr: next_rx_page = %d\n", next_rx_page));

	/* Tell the adapter that we are going to read data, and from where */
	de620_send_command(dev, W_CR | RRN);
	de620_set_register(dev, W_RSA1, next_rx_page);
	de620_set_register(dev, W_RSA0, 0);

	/* Deep breath, and away we goooooo */
	de620_read_block(dev, (byte *)&header_buf, sizeof(struct header_buf));
	PRINTK(("page status=0x%02x, nextpage=%d, packetsize=%d\n",
	header_buf.status, header_buf.Rx_NextPage, header_buf.Rx_ByteCount));

	/* Plausible page header? */
	pagelink = header_buf.Rx_NextPage;
	if ((pagelink < first_rx_page) || (last_rx_page < pagelink)) {
		/* Ouch... Forget it! Skip all and start afresh... */
		printk(KERN_WARNING "%s: Ring overrun? Restoring...\n", dev->name);
		/* You win some, you lose some. And sometimes plenty... */
		adapter_init(dev);
		netif_wake_queue(dev);
		((struct net_device_stats *)(dev->priv))->rx_over_errors++;
		return 0;
	}

	/* OK, this look good, so far. Let's see if it's consistent... */
	/* Let's compute the start of the next packet, based on where we are */
	pagelink = next_rx_page +
		((header_buf.Rx_ByteCount + (4 - 1 + 0x100)) >> 8);

	/* Are we going to wrap around the page counter? */
	if (pagelink > last_rx_page)
		pagelink -= (last_rx_page - first_rx_page + 1);

	/* Is the _computed_ next page number equal to what the adapter says? */
	if (pagelink != header_buf.Rx_NextPage) {
		/* Naah, we'll skip this packet. Probably bogus data as well */
		printk(KERN_WARNING "%s: Page link out of sync! Restoring...\n", dev->name);
		next_rx_page = header_buf.Rx_NextPage; /* at least a try... */
		de620_send_command(dev, W_DUMMY);
		de620_set_register(dev, W_NPRF, next_rx_page);
		((struct net_device_stats *)(dev->priv))->rx_over_errors++;
		return 0;
	}
	next_rx_page = pagelink;

	size = header_buf.Rx_ByteCount - 4;
	if ((size < RUNT) || (GIANT < size)) {
		printk(KERN_WARNING "%s: Illegal packet size: %d!\n", dev->name, size);
	}
	else { /* Good packet? */
		skb = dev_alloc_skb(size+2);
		if (skb == NULL) { /* Yeah, but no place to put it... */
			printk(KERN_WARNING "%s: Couldn't allocate a sk_buff of size %d.\n", dev->name, size);
			((struct net_device_stats *)(dev->priv))->rx_dropped++;
		}
		else { /* Yep! Go get it! */
			skb_reserve(skb,2);	/* Align */
			skb->dev = dev;
			/* skb->data points to the start of sk_buff data area */
			buffer = skb_put(skb,size);
			/* copy the packet into the buffer */
			de620_read_block(dev, buffer, size);
			PRINTK(("Read %d bytes\n", size));
			skb->protocol=eth_type_trans(skb,dev);
			netif_rx(skb); /* deliver it "upstairs" */
			dev->last_rx = jiffies;
			/* count all receives */
			((struct net_device_stats *)(dev->priv))->rx_packets++;
			((struct net_device_stats *)(dev->priv))->rx_bytes += size;
		}
	}

	/* Let's peek ahead to see if we have read the last current packet */
	/* NOTE! We're _not_ checking the 'EMPTY'-flag! This seems better... */
	curr_page = de620_get_register(dev, R_CPR);
	de620_set_register(dev, W_NPRF, next_rx_page);
	PRINTK(("next_rx_page=%d CPR=%d\n", next_rx_page, curr_page));

	return (next_rx_page != curr_page); /* That was slightly tricky... */
}

/*********************************************
 *
 * Reset the adapter to a known state
 *
 */
static int adapter_init(struct net_device *dev)
{
	int i;
	static int was_down;

	if ((nic_data.Model == 3) || (nic_data.Model == 0)) { /* CT */
		EIPRegister = NCTL0;
		if (nic_data.Media != 1)
			EIPRegister |= NIS0;	/* not BNC */
	}
	else if (nic_data.Model == 2) { /* UTP */
		EIPRegister = NCTL0 | NIS0;
	}

	if (utp)
		EIPRegister = NCTL0 | NIS0;
	if (bnc)
		EIPRegister = NCTL0;

	de620_send_command(dev, W_CR | RNOP | CLEAR);
	de620_send_command(dev, W_CR | RNOP);

	de620_set_register(dev, W_SCR, SCR_DEF);
	/* disable recv to wait init */
	de620_set_register(dev, W_TCR, RXOFF);

	/* Set the node ID in the adapter */
	for (i = 0; i < 6; ++i) { /* W_PARn = 0xaa + n */
		de620_set_register(dev, W_PAR0 + i, dev->dev_addr[i]);
	}

	de620_set_register(dev, W_EIP, EIPRegister);

	next_rx_page = first_rx_page = DE620_RX_START_PAGE;
	if (nic_data.RAM_Size)
		last_rx_page = nic_data.RAM_Size - 1;
	else /* 64k RAM */
		last_rx_page = 255;

	de620_set_register(dev, W_SPR, first_rx_page); /* Start Page Register*/
	de620_set_register(dev, W_EPR, last_rx_page);  /* End Page Register */
	de620_set_register(dev, W_CPR, first_rx_page);/*Current Page Register*/
	de620_send_command(dev, W_NPR | first_rx_page); /* Next Page Register*/
	de620_send_command(dev, W_DUMMY);
	de620_set_delay(dev);

	/* Final sanity check: Anybody out there? */
	/* Let's hope some bits from the statusregister make a good check */
#define CHECK_MASK (  0 | TXSUC |  T16  |  0  | RXCRC | RXSHORT |  0  |  0  )
#define CHECK_OK   (  0 |   0   |  0    |  0  |   0   |   0     |  0  |  0  )
        /* success:   X     0      0       X      0       0        X     X  */
        /* ignore:   EEDI                RXGOOD                   COLS  LNKS*/

	if (((i = de620_get_register(dev, R_STS)) & CHECK_MASK) != CHECK_OK) {
		printk(KERN_ERR "%s: Something has happened to the DE-620!  Please check it"
#ifdef SHUTDOWN_WHEN_LOST
			" and do a new ifconfig"
#endif
			"! (%02x)\n", dev->name, i);
#ifdef SHUTDOWN_WHEN_LOST
		/* Goodbye, cruel world... */
		dev->flags &= ~IFF_UP;
		de620_close(dev);
#endif
		was_down = 1;
		return 1; /* failed */
	}
	if (was_down) {
		printk(KERN_WARNING "%s: Thanks, I feel much better now!\n", dev->name);
		was_down = 0;
	}

	/* All OK, go ahead... */
	de620_set_register(dev, W_TCR, TCR_DEF);

	return 0; /* all ok */
}

/******************************************************************************
 *
 * Only start-up code below
 *
 */
/****************************************
 *
 * Check if there is a DE-620 connected
 */
struct net_device * __init de620_probe(int unit)
{
	byte checkbyte = 0xa5;
	struct net_device *dev;
	int err = -ENOMEM;
	int i;

	dev = alloc_etherdev(sizeof(struct net_device_stats));
	if (!dev)
		goto out;

	SET_MODULE_OWNER(dev);

	spin_lock_init(&de620_lock);
	
	/*
	 * This is where the base_addr and irq gets set.
	 * Tunable at compile-time and insmod-time
	 */
	dev->base_addr = io;
	dev->irq       = irq;

	/* allow overriding parameters on command line */
	if (unit >= 0) {
		sprintf(dev->name, "eth%d", unit);
		netdev_boot_setup_check(dev);
	}
	
	if (de620_debug)
		printk(version);

	printk(KERN_INFO "D-Link DE-620 pocket adapter");

	if (!request_region(dev->base_addr, 3, "de620")) {
		printk(" io 0x%3lX, which is busy.\n", dev->base_addr);
		err = -EBUSY;
		goto out1;
	}

	/* Initially, configure basic nibble mode, so we can read the EEPROM */
	NIC_Cmd = DEF_NIC_CMD;
	de620_set_register(dev, W_EIP, EIPRegister);

	/* Anybody out there? */
	de620_set_register(dev, W_CPR, checkbyte);
	checkbyte = de620_get_register(dev, R_CPR);

	if ((checkbyte != 0xa5) || (read_eeprom(dev) != 0)) {
		printk(" not identified in the printer port\n");
		err = -ENODEV;
		goto out2;
	}

	/* else, got it! */
	printk(", Ethernet Address: %2.2X",
		dev->dev_addr[0] = nic_data.NodeID[0]);
	for (i = 1; i < ETH_ALEN; i++) {
		printk(":%2.2X", dev->dev_addr[i] = nic_data.NodeID[i]);
		dev->broadcast[i] = 0xff;
	}

	printk(" (%dk RAM,",
		(nic_data.RAM_Size) ? (nic_data.RAM_Size >> 2) : 64);

	if (nic_data.Media == 1)
		printk(" BNC)\n");
	else
		printk(" UTP)\n");

	dev->get_stats 		= get_stats;
	dev->open 		= de620_open;
	dev->stop 		= de620_close;
	dev->hard_start_xmit 	= de620_start_xmit;
	dev->tx_timeout 	= de620_timeout;
	dev->watchdog_timeo	= HZ*2;
	dev->set_multicast_list = de620_set_multicast_list;
	
	/* base_addr and irq are already set, see above! */

	/* dump eeprom */
	if (de620_debug) {
		printk("\nEEPROM contents:\n");
		printk("RAM_Size = 0x%02X\n", nic_data.RAM_Size);
		printk("NodeID = %02X:%02X:%02X:%02X:%02X:%02X\n",
			nic_data.NodeID[0], nic_data.NodeID[1],
			nic_data.NodeID[2], nic_data.NodeID[3],
			nic_data.NodeID[4], nic_data.NodeID[5]);
		printk("Model = %d\n", nic_data.Model);
		printk("Media = %d\n", nic_data.Media);
		printk("SCR = 0x%02x\n", nic_data.SCR);
	}

	err = register_netdev(dev);
	if (err)
		goto out2;
	return dev;

out2:
	release_region(dev->base_addr, 3);
out1:
	free_netdev(dev);
out:
	return ERR_PTR(err);
}

/**********************************
 *
 * Read info from on-board EEPROM
 *
 * Note: Bitwise serial I/O to/from the EEPROM vi the status _register_!
 */
#define sendit(dev,data) de620_set_register(dev, W_EIP, data | EIPRegister);

static unsigned short __init ReadAWord(struct net_device *dev, int from)
{
	unsigned short data;
	int nbits;

	/* cs   [__~~] SET SEND STATE */
	/* di   [____]                */
	/* sck  [_~~_]                */
	sendit(dev, 0); sendit(dev, 1); sendit(dev, 5); sendit(dev, 4);

	/* Send the 9-bit address from where we want to read the 16-bit word */
	for (nbits = 9; nbits > 0; --nbits, from <<= 1) {
		if (from & 0x0100) { /* bit set? */
			/* cs    [~~~~] SEND 1 */
			/* di    [~~~~]        */
			/* sck   [_~~_]        */
			sendit(dev, 6); sendit(dev, 7); sendit(dev, 7); sendit(dev, 6);
		}
		else {
			/* cs    [~~~~] SEND 0 */
			/* di    [____]        */
			/* sck   [_~~_]        */
			sendit(dev, 4); sendit(dev, 5); sendit(dev, 5); sendit(dev, 4);
		}
	}

	/* Shift in the 16-bit word. The bits appear serially in EEDI (=0x80) */
	for (data = 0, nbits = 16; nbits > 0; --nbits) {
		/* cs    [~~~~] SEND 0 */
		/* di    [____]        */
		/* sck   [_~~_]        */
		sendit(dev, 4); sendit(dev, 5); sendit(dev, 5); sendit(dev, 4);
		data = (data << 1) | ((de620_get_register(dev, R_STS) & EEDI) >> 7);
	}
	/* cs    [____] RESET SEND STATE */
	/* di    [____]                  */
	/* sck   [_~~_]                  */
	sendit(dev, 0); sendit(dev, 1); sendit(dev, 1); sendit(dev, 0);

	return data;
}

static int __init read_eeprom(struct net_device *dev)
{
	unsigned short wrd;

	/* D-Link Ethernet addresses are in the series  00:80:c8:7X:XX:XX:XX */
	wrd = ReadAWord(dev, 0x1aa);	/* bytes 0 + 1 of NodeID */
	if (!clone && (wrd != htons(0x0080))) /* Valid D-Link ether sequence? */
		return -1; /* Nope, not a DE-620 */
	nic_data.NodeID[0] = wrd & 0xff;
	nic_data.NodeID[1] = wrd >> 8;

	wrd = ReadAWord(dev, 0x1ab);	/* bytes 2 + 3 of NodeID */
	if (!clone && ((wrd & 0xff) != 0xc8)) /* Valid D-Link ether sequence? */
		return -1; /* Nope, not a DE-620 */
	nic_data.NodeID[2] = wrd & 0xff;
	nic_data.NodeID[3] = wrd >> 8;

	wrd = ReadAWord(dev, 0x1ac);	/* bytes 4 + 5 of NodeID */
	nic_data.NodeID[4] = wrd & 0xff;
	nic_data.NodeID[5] = wrd >> 8;

	wrd = ReadAWord(dev, 0x1ad);	/* RAM size in pages (256 bytes). 0 = 64k */
	nic_data.RAM_Size = (wrd >> 8);

	wrd = ReadAWord(dev, 0x1ae);	/* hardware model (CT = 3) */
	nic_data.Model = (wrd & 0xff);

	wrd = ReadAWord(dev, 0x1af); /* media (indicates BNC/UTP) */
	nic_data.Media = (wrd & 0xff);

	wrd = ReadAWord(dev, 0x1a8); /* System Configuration Register */
	nic_data.SCR = (wrd >> 8);

	return 0; /* no errors */
}

/******************************************************************************
 *
 * Loadable module skeleton
 *
 */
#ifdef MODULE
static struct net_device *de620_dev;

int init_module(void)
{
	de620_dev = de620_probe(-1);
	if (IS_ERR(de620_dev))
		return PTR_ERR(de620_dev);
	return 0;
}

void cleanup_module(void)
{
	unregister_netdev(de620_dev);
	release_region(de620_dev->base_addr, 3);
	free_netdev(de620_dev);
}
#endif /* MODULE */
MODULE_LICENSE("GPL");


/*
 * (add '-DMODULE' when compiling as loadable module)
 *
 * compile-command:
 *	gcc -D__KERNEL__ -Wall -Wstrict-prototypes -O2 \
 *	 -fomit-frame-pointer -m486 \
 *	-I/usr/src/linux/include -I../../net/inet -c de620.c
*/
/*
 * Local variables:
 *  kernel-compile-command: "gcc -D__KERNEL__ -Ilinux/include -I../../net/inet -Wall -Wstrict-prototypes -O2 -m486 -c de620.c"
 *  module-compile-command: "gcc -D__KERNEL__ -DMODULE -Ilinux/include -I../../net/inet -Wall -Wstrict-prototypes -O2 -m486 -c de620.c"
 *  compile-command: "gcc -D__KERNEL__ -DMODULE -Ilinux/include -I../../net/inet -Wall -Wstrict-prototypes -O2 -m486 -c de620.c"
 * End:
 */