summaryrefslogtreecommitdiffstats
path: root/drivers/net/tulip/interrupt.c
blob: afb5cda9d8e1e32ed17424bfa0749f492470712f (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
/*
	drivers/net/tulip/interrupt.c

	Maintained by Jeff Garzik <jgarzik@pobox.com>
	Copyright 2000,2001  The Linux Kernel Team
	Written/copyright 1994-2001 by Donald Becker.

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

	Please refer to Documentation/DocBook/tulip-user.{pdf,ps,html}
	for more information on this driver, or visit the project
	Web page at http://sourceforge.net/projects/tulip/

*/

#include <linux/pci.h>
#include "tulip.h"
#include <linux/config.h>
#include <linux/etherdevice.h>

int tulip_rx_copybreak;
unsigned int tulip_max_interrupt_work;

#ifdef CONFIG_TULIP_NAPI_HW_MITIGATION
#define MIT_SIZE 15
#define MIT_TABLE 15 /* We use 0 or max */

static unsigned int mit_table[MIT_SIZE+1] =
{
        /*  CRS11 21143 hardware Mitigation Control Interrupt
            We use only RX mitigation we other techniques for
            TX intr. mitigation.

           31    Cycle Size (timer control)
           30:27 TX timer in 16 * Cycle size
           26:24 TX No pkts before Int.
           23:20 RX timer in Cycle size
           19:17 RX No pkts before Int.
           16       Continues Mode (CM)
        */

        0x0,             /* IM disabled */
        0x80150000,      /* RX time = 1, RX pkts = 2, CM = 1 */
        0x80150000,
        0x80270000,
        0x80370000,
        0x80490000,
        0x80590000,
        0x80690000,
        0x807B0000,
        0x808B0000,
        0x809D0000,
        0x80AD0000,
        0x80BD0000,
        0x80CF0000,
        0x80DF0000,
//       0x80FF0000      /* RX time = 16, RX pkts = 7, CM = 1 */
        0x80F10000      /* RX time = 16, RX pkts = 0, CM = 1 */
};
#endif


int tulip_refill_rx(struct net_device *dev)
{
	struct tulip_private *tp = netdev_priv(dev);
	int entry;
	int refilled = 0;

	/* Refill the Rx ring buffers. */
	for (; tp->cur_rx - tp->dirty_rx > 0; tp->dirty_rx++) {
		entry = tp->dirty_rx % RX_RING_SIZE;
		if (tp->rx_buffers[entry].skb == NULL) {
			struct sk_buff *skb;
			dma_addr_t mapping;

			skb = tp->rx_buffers[entry].skb = dev_alloc_skb(PKT_BUF_SZ);
			if (skb == NULL)
				break;

			mapping = pci_map_single(tp->pdev, skb->tail, PKT_BUF_SZ,
						 PCI_DMA_FROMDEVICE);
			tp->rx_buffers[entry].mapping = mapping;

			skb->dev = dev;			/* Mark as being used by this device. */
			tp->rx_ring[entry].buffer1 = cpu_to_le32(mapping);
			refilled++;
		}
		tp->rx_ring[entry].status = cpu_to_le32(DescOwned);
	}
	if(tp->chip_id == LC82C168) {
		if(((ioread32(tp->base_addr + CSR5)>>17)&0x07) == 4) {
			/* Rx stopped due to out of buffers,
			 * restart it
			 */
			iowrite32(0x01, tp->base_addr + CSR2);
		}
	}
	return refilled;
}

#ifdef CONFIG_TULIP_NAPI

void oom_timer(unsigned long data)
{
        struct net_device *dev = (struct net_device *)data;
	netif_rx_schedule(dev);
}

int tulip_poll(struct net_device *dev, int *budget)
{
	struct tulip_private *tp = netdev_priv(dev);
	int entry = tp->cur_rx % RX_RING_SIZE;
	int rx_work_limit = *budget;
	int received = 0;

	if (!netif_running(dev))
		goto done;

	if (rx_work_limit > dev->quota)
		rx_work_limit = dev->quota;

#ifdef CONFIG_TULIP_NAPI_HW_MITIGATION

/* that one buffer is needed for mit activation; or might be a
   bug in the ring buffer code; check later -- JHS*/

        if (rx_work_limit >=RX_RING_SIZE) rx_work_limit--;
#endif

	if (tulip_debug > 4)
		printk(KERN_DEBUG " In tulip_rx(), entry %d %8.8x.\n", entry,
			   tp->rx_ring[entry].status);

       do {
		if (ioread32(tp->base_addr + CSR5) == 0xffffffff) {
			printk(KERN_DEBUG " In tulip_poll(), hardware disappeared.\n");
			break;
		}
               /* Acknowledge current RX interrupt sources. */
               iowrite32((RxIntr | RxNoBuf), tp->base_addr + CSR5);
 
 
               /* If we own the next entry, it is a new packet. Send it up. */
               while ( ! (tp->rx_ring[entry].status & cpu_to_le32(DescOwned))) {
                       s32 status = le32_to_cpu(tp->rx_ring[entry].status);
 
 
                       if (tp->dirty_rx + RX_RING_SIZE == tp->cur_rx)
                               break;
 
                       if (tulip_debug > 5)
                               printk(KERN_DEBUG "%s: In tulip_rx(), entry %d %8.8x.\n",
                                      dev->name, entry, status);
                       if (--rx_work_limit < 0)
                               goto not_done;
 
                       if ((status & 0x38008300) != 0x0300) {
                               if ((status & 0x38000300) != 0x0300) {
                                /* Ingore earlier buffers. */
                                       if ((status & 0xffff) != 0x7fff) {
                                               if (tulip_debug > 1)
                                                       printk(KERN_WARNING "%s: Oversized Ethernet frame "
                                                              "spanned multiple buffers, status %8.8x!\n",
                                                              dev->name, status);
                                               tp->stats.rx_length_errors++;
                                       }
                               } else if (status & RxDescFatalErr) {
                                /* There was a fatal error. */
                                       if (tulip_debug > 2)
                                               printk(KERN_DEBUG "%s: Receive error, Rx status %8.8x.\n",
                                                      dev->name, status);
                                       tp->stats.rx_errors++; /* end of a packet.*/
                                       if (status & 0x0890) tp->stats.rx_length_errors++;
                                       if (status & 0x0004) tp->stats.rx_frame_errors++;
                                       if (status & 0x0002) tp->stats.rx_crc_errors++;
                                       if (status & 0x0001) tp->stats.rx_fifo_errors++;
                               }
                       } else {
                               /* Omit the four octet CRC from the length. */
                               short pkt_len = ((status >> 16) & 0x7ff) - 4;
                               struct sk_buff *skb;
  
#ifndef final_version
                               if (pkt_len > 1518) {
                                       printk(KERN_WARNING "%s: Bogus packet size of %d (%#x).\n",
                                              dev->name, pkt_len, pkt_len);
                                       pkt_len = 1518;
                                       tp->stats.rx_length_errors++;
                               }
#endif
                               /* Check if the packet is long enough to accept without copying
                                  to a minimally-sized skbuff. */
                               if (pkt_len < tulip_rx_copybreak
                                   && (skb = dev_alloc_skb(pkt_len + 2)) != NULL) {
                                       skb->dev = dev;
                                       skb_reserve(skb, 2);    /* 16 byte align the IP header */
                                       pci_dma_sync_single_for_cpu(tp->pdev,
								   tp->rx_buffers[entry].mapping,
								   pkt_len, PCI_DMA_FROMDEVICE);
#if ! defined(__alpha__)
                                       eth_copy_and_sum(skb, tp->rx_buffers[entry].skb->tail,
                                                        pkt_len, 0);
                                       skb_put(skb, pkt_len);
#else
                                       memcpy(skb_put(skb, pkt_len),
                                              tp->rx_buffers[entry].skb->tail,
                                              pkt_len);
#endif
                                       pci_dma_sync_single_for_device(tp->pdev,
								      tp->rx_buffers[entry].mapping,
								      pkt_len, PCI_DMA_FROMDEVICE);
                               } else {        /* Pass up the skb already on the Rx ring. */
                                       char *temp = skb_put(skb = tp->rx_buffers[entry].skb,
                                                            pkt_len);
  
#ifndef final_version
                                       if (tp->rx_buffers[entry].mapping !=
                                           le32_to_cpu(tp->rx_ring[entry].buffer1)) {
                                               printk(KERN_ERR "%s: Internal fault: The skbuff addresses "
                                                      "do not match in tulip_rx: %08x vs. %08llx %p / %p.\n",
                                                      dev->name,
                                                      le32_to_cpu(tp->rx_ring[entry].buffer1),
                                                      (unsigned long long)tp->rx_buffers[entry].mapping,
                                                      skb->head, temp);
                                       }
#endif
  
                                       pci_unmap_single(tp->pdev, tp->rx_buffers[entry].mapping,
                                                        PKT_BUF_SZ, PCI_DMA_FROMDEVICE);
  
                                       tp->rx_buffers[entry].skb = NULL;
                                       tp->rx_buffers[entry].mapping = 0;
                               }
                               skb->protocol = eth_type_trans(skb, dev);
  
                               netif_receive_skb(skb);
 
                               dev->last_rx = jiffies;
                               tp->stats.rx_packets++;
                               tp->stats.rx_bytes += pkt_len;
                       }
                       received++;

                       entry = (++tp->cur_rx) % RX_RING_SIZE;
                       if (tp->cur_rx - tp->dirty_rx > RX_RING_SIZE/4)
                               tulip_refill_rx(dev);
 
                }
 
               /* New ack strategy... irq does not ack Rx any longer
                  hopefully this helps */
 
               /* Really bad things can happen here... If new packet arrives
                * and an irq arrives (tx or just due to occasionally unset
                * mask), it will be acked by irq handler, but new thread
                * is not scheduled. It is major hole in design.
                * No idea how to fix this if "playing with fire" will fail
                * tomorrow (night 011029). If it will not fail, we won
                * finally: amount of IO did not increase at all. */
       } while ((ioread32(tp->base_addr + CSR5) & RxIntr));
 
done:
 
 #ifdef CONFIG_TULIP_NAPI_HW_MITIGATION
  
          /* We use this simplistic scheme for IM. It's proven by
             real life installations. We can have IM enabled
            continuesly but this would cause unnecessary latency. 
            Unfortunely we can't use all the NET_RX_* feedback here. 
            This would turn on IM for devices that is not contributing 
            to backlog congestion with unnecessary latency. 
  
             We monitor the the device RX-ring and have:
  
             HW Interrupt Mitigation either ON or OFF.
  
            ON:  More then 1 pkt received (per intr.) OR we are dropping 
             OFF: Only 1 pkt received
            
             Note. We only use min and max (0, 15) settings from mit_table */
  
  
          if( tp->flags &  HAS_INTR_MITIGATION) {
                 if( received > 1 ) {
                         if( ! tp->mit_on ) {
                                 tp->mit_on = 1;
                                 iowrite32(mit_table[MIT_TABLE], tp->base_addr + CSR11);
                         }
                  }
                 else {
                         if( tp->mit_on ) {
                                 tp->mit_on = 0;
                                 iowrite32(0, tp->base_addr + CSR11);
                         }
                  }
          }

#endif /* CONFIG_TULIP_NAPI_HW_MITIGATION */
 
         dev->quota -= received;
         *budget -= received;
 
         tulip_refill_rx(dev);
         
         /* If RX ring is not full we are out of memory. */
         if (tp->rx_buffers[tp->dirty_rx % RX_RING_SIZE].skb == NULL) goto oom;
 
         /* Remove us from polling list and enable RX intr. */
 
         netif_rx_complete(dev);
         iowrite32(tulip_tbl[tp->chip_id].valid_intrs, tp->base_addr+CSR7);
 
         /* The last op happens after poll completion. Which means the following:
          * 1. it can race with disabling irqs in irq handler
          * 2. it can race with dise/enabling irqs in other poll threads
          * 3. if an irq raised after beginning loop, it will be immediately
          *    triggered here.
          *
          * Summarizing: the logic results in some redundant irqs both
          * due to races in masking and due to too late acking of already
          * processed irqs. But it must not result in losing events.
          */
 
         return 0;
 
 not_done:
         if (!received) {

                 received = dev->quota; /* Not to happen */
         }
         dev->quota -= received;
         *budget -= received;
 
         if (tp->cur_rx - tp->dirty_rx > RX_RING_SIZE/2 ||
             tp->rx_buffers[tp->dirty_rx % RX_RING_SIZE].skb == NULL)
                 tulip_refill_rx(dev);
 
         if (tp->rx_buffers[tp->dirty_rx % RX_RING_SIZE].skb == NULL) goto oom;
 
         return 1;
 
 
 oom:    /* Executed with RX ints disabled */
 
         
         /* Start timer, stop polling, but do not enable rx interrupts. */
         mod_timer(&tp->oom_timer, jiffies+1);
       
         /* Think: timer_pending() was an explicit signature of bug.
          * Timer can be pending now but fired and completed
          * before we did netif_rx_complete(). See? We would lose it. */
 
         /* remove ourselves from the polling list */
         netif_rx_complete(dev);
 
         return 0;
}

#else /* CONFIG_TULIP_NAPI */

static int tulip_rx(struct net_device *dev)
{
	struct tulip_private *tp = netdev_priv(dev);
	int entry = tp->cur_rx % RX_RING_SIZE;
	int rx_work_limit = tp->dirty_rx + RX_RING_SIZE - tp->cur_rx;
	int received = 0;

	if (tulip_debug > 4)
		printk(KERN_DEBUG " In tulip_rx(), entry %d %8.8x.\n", entry,
			   tp->rx_ring[entry].status);
	/* If we own the next entry, it is a new packet. Send it up. */
	while ( ! (tp->rx_ring[entry].status & cpu_to_le32(DescOwned))) {
		s32 status = le32_to_cpu(tp->rx_ring[entry].status);

		if (tulip_debug > 5)
			printk(KERN_DEBUG "%s: In tulip_rx(), entry %d %8.8x.\n",
				   dev->name, entry, status);
		if (--rx_work_limit < 0)
			break;
		if ((status & 0x38008300) != 0x0300) {
			if ((status & 0x38000300) != 0x0300) {
				/* Ingore earlier buffers. */
				if ((status & 0xffff) != 0x7fff) {
					if (tulip_debug > 1)
						printk(KERN_WARNING "%s: Oversized Ethernet frame "
							   "spanned multiple buffers, status %8.8x!\n",
							   dev->name, status);
					tp->stats.rx_length_errors++;
				}
			} else if (status & RxDescFatalErr) {
				/* There was a fatal error. */
				if (tulip_debug > 2)
					printk(KERN_DEBUG "%s: Receive error, Rx status %8.8x.\n",
						   dev->name, status);
				tp->stats.rx_errors++; /* end of a packet.*/
				if (status & 0x0890) tp->stats.rx_length_errors++;
				if (status & 0x0004) tp->stats.rx_frame_errors++;
				if (status & 0x0002) tp->stats.rx_crc_errors++;
				if (status & 0x0001) tp->stats.rx_fifo_errors++;
			}
		} else {
			/* Omit the four octet CRC from the length. */
			short pkt_len = ((status >> 16) & 0x7ff) - 4;
			struct sk_buff *skb;

#ifndef final_version
			if (pkt_len > 1518) {
				printk(KERN_WARNING "%s: Bogus packet size of %d (%#x).\n",
					   dev->name, pkt_len, pkt_len);
				pkt_len = 1518;
				tp->stats.rx_length_errors++;
			}
#endif

			/* Check if the packet is long enough to accept without copying
			   to a minimally-sized skbuff. */
			if (pkt_len < tulip_rx_copybreak
				&& (skb = dev_alloc_skb(pkt_len + 2)) != NULL) {
				skb->dev = dev;
				skb_reserve(skb, 2);	/* 16 byte align the IP header */
				pci_dma_sync_single_for_cpu(tp->pdev,
							    tp->rx_buffers[entry].mapping,
							    pkt_len, PCI_DMA_FROMDEVICE);
#if ! defined(__alpha__)
				eth_copy_and_sum(skb, tp->rx_buffers[entry].skb->tail,
						 pkt_len, 0);
				skb_put(skb, pkt_len);
#else
				memcpy(skb_put(skb, pkt_len),
				       tp->rx_buffers[entry].skb->tail,
				       pkt_len);
#endif
				pci_dma_sync_single_for_device(tp->pdev,
							       tp->rx_buffers[entry].mapping,
							       pkt_len, PCI_DMA_FROMDEVICE);
			} else { 	/* Pass up the skb already on the Rx ring. */
				char *temp = skb_put(skb = tp->rx_buffers[entry].skb,
						     pkt_len);

#ifndef final_version
				if (tp->rx_buffers[entry].mapping !=
				    le32_to_cpu(tp->rx_ring[entry].buffer1)) {
					printk(KERN_ERR "%s: Internal fault: The skbuff addresses "
					       "do not match in tulip_rx: %08x vs. %Lx %p / %p.\n",
					       dev->name,
					       le32_to_cpu(tp->rx_ring[entry].buffer1),
					       (long long)tp->rx_buffers[entry].mapping,
					       skb->head, temp);
				}
#endif

				pci_unmap_single(tp->pdev, tp->rx_buffers[entry].mapping,
						 PKT_BUF_SZ, PCI_DMA_FROMDEVICE);

				tp->rx_buffers[entry].skb = NULL;
				tp->rx_buffers[entry].mapping = 0;
			}
			skb->protocol = eth_type_trans(skb, dev);

			netif_rx(skb);

			dev->last_rx = jiffies;
			tp->stats.rx_packets++;
			tp->stats.rx_bytes += pkt_len;
		}
		received++;
		entry = (++tp->cur_rx) % RX_RING_SIZE;
	}
	return received;
}
#endif  /* CONFIG_TULIP_NAPI */

static inline unsigned int phy_interrupt (struct net_device *dev)
{
#ifdef __hppa__
	struct tulip_private *tp = netdev_priv(dev);
	int csr12 = ioread32(tp->base_addr + CSR12) & 0xff;

	if (csr12 != tp->csr12_shadow) {
		/* ack interrupt */
		iowrite32(csr12 | 0x02, tp->base_addr + CSR12);
		tp->csr12_shadow = csr12;
		/* do link change stuff */
		spin_lock(&tp->lock);
		tulip_check_duplex(dev);
		spin_unlock(&tp->lock);
		/* clear irq ack bit */
		iowrite32(csr12 & ~0x02, tp->base_addr + CSR12);

		return 1;
	}
#endif

	return 0;
}

/* The interrupt handler does all of the Rx thread work and cleans up
   after the Tx thread. */
irqreturn_t tulip_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
{
	struct net_device *dev = (struct net_device *)dev_instance;
	struct tulip_private *tp = netdev_priv(dev);
	void __iomem *ioaddr = tp->base_addr;
	int csr5;
	int missed;
	int rx = 0;
	int tx = 0;
	int oi = 0;
	int maxrx = RX_RING_SIZE;
	int maxtx = TX_RING_SIZE;
	int maxoi = TX_RING_SIZE;
#ifdef CONFIG_TULIP_NAPI
	int rxd = 0;
#else
	int entry;
#endif
	unsigned int work_count = tulip_max_interrupt_work;
	unsigned int handled = 0;

	/* Let's see whether the interrupt really is for us */
	csr5 = ioread32(ioaddr + CSR5);

        if (tp->flags & HAS_PHY_IRQ) 
	        handled = phy_interrupt (dev);
    
	if ((csr5 & (NormalIntr|AbnormalIntr)) == 0)
		return IRQ_RETVAL(handled);

	tp->nir++;

	do {

#ifdef CONFIG_TULIP_NAPI

		if (!rxd && (csr5 & (RxIntr | RxNoBuf))) {
			rxd++;
			/* Mask RX intrs and add the device to poll list. */
			iowrite32(tulip_tbl[tp->chip_id].valid_intrs&~RxPollInt, ioaddr + CSR7);
			netif_rx_schedule(dev);
			
			if (!(csr5&~(AbnormalIntr|NormalIntr|RxPollInt|TPLnkPass)))
                               break;
		}
		
               /* Acknowledge the interrupt sources we handle here ASAP
                  the poll function does Rx and RxNoBuf acking */
		
		iowrite32(csr5 & 0x0001ff3f, ioaddr + CSR5);

#else 
		/* Acknowledge all of the current interrupt sources ASAP. */
		iowrite32(csr5 & 0x0001ffff, ioaddr + CSR5);


		if (csr5 & (RxIntr | RxNoBuf)) {
				rx += tulip_rx(dev);
			tulip_refill_rx(dev);
		}

#endif /*  CONFIG_TULIP_NAPI */
		
		if (tulip_debug > 4)
			printk(KERN_DEBUG "%s: interrupt  csr5=%#8.8x new csr5=%#8.8x.\n",
			       dev->name, csr5, ioread32(ioaddr + CSR5));
		

		if (csr5 & (TxNoBuf | TxDied | TxIntr | TimerInt)) {
			unsigned int dirty_tx;

			spin_lock(&tp->lock);

			for (dirty_tx = tp->dirty_tx; tp->cur_tx - dirty_tx > 0;
				 dirty_tx++) {
				int entry = dirty_tx % TX_RING_SIZE;
				int status = le32_to_cpu(tp->tx_ring[entry].status);

				if (status < 0)
					break;			/* It still has not been Txed */

				/* Check for Rx filter setup frames. */
				if (tp->tx_buffers[entry].skb == NULL) {
					/* test because dummy frames not mapped */
					if (tp->tx_buffers[entry].mapping)
						pci_unmap_single(tp->pdev,
							 tp->tx_buffers[entry].mapping,
							 sizeof(tp->setup_frame),
							 PCI_DMA_TODEVICE);
					continue;
				}

				if (status & 0x8000) {
					/* There was an major error, log it. */
#ifndef final_version
					if (tulip_debug > 1)
						printk(KERN_DEBUG "%s: Transmit error, Tx status %8.8x.\n",
							   dev->name, status);
#endif
					tp->stats.tx_errors++;
					if (status & 0x4104) tp->stats.tx_aborted_errors++;
					if (status & 0x0C00) tp->stats.tx_carrier_errors++;
					if (status & 0x0200) tp->stats.tx_window_errors++;
					if (status & 0x0002) tp->stats.tx_fifo_errors++;
					if ((status & 0x0080) && tp->full_duplex == 0)
						tp->stats.tx_heartbeat_errors++;
				} else {
					tp->stats.tx_bytes +=
						tp->tx_buffers[entry].skb->len;
					tp->stats.collisions += (status >> 3) & 15;
					tp->stats.tx_packets++;
				}

				pci_unmap_single(tp->pdev, tp->tx_buffers[entry].mapping,
						 tp->tx_buffers[entry].skb->len,
						 PCI_DMA_TODEVICE);

				/* Free the original skb. */
				dev_kfree_skb_irq(tp->tx_buffers[entry].skb);
				tp->tx_buffers[entry].skb = NULL;
				tp->tx_buffers[entry].mapping = 0;
				tx++;
			}

#ifndef final_version
			if (tp->cur_tx - dirty_tx > TX_RING_SIZE) {
				printk(KERN_ERR "%s: Out-of-sync dirty pointer, %d vs. %d.\n",
					   dev->name, dirty_tx, tp->cur_tx);
				dirty_tx += TX_RING_SIZE;
			}
#endif

			if (tp->cur_tx - dirty_tx < TX_RING_SIZE - 2)
				netif_wake_queue(dev);

			tp->dirty_tx = dirty_tx;
			if (csr5 & TxDied) {
				if (tulip_debug > 2)
					printk(KERN_WARNING "%s: The transmitter stopped."
						   "  CSR5 is %x, CSR6 %x, new CSR6 %x.\n",
						   dev->name, csr5, ioread32(ioaddr + CSR6), tp->csr6);
				tulip_restart_rxtx(tp);
			}
			spin_unlock(&tp->lock);
		}

		/* Log errors. */
		if (csr5 & AbnormalIntr) {	/* Abnormal error summary bit. */
			if (csr5 == 0xffffffff)
				break;
			if (csr5 & TxJabber) tp->stats.tx_errors++;
			if (csr5 & TxFIFOUnderflow) {
				if ((tp->csr6 & 0xC000) != 0xC000)
					tp->csr6 += 0x4000;	/* Bump up the Tx threshold */
				else
					tp->csr6 |= 0x00200000;  /* Store-n-forward. */
				/* Restart the transmit process. */
				tulip_restart_rxtx(tp);
				iowrite32(0, ioaddr + CSR1);
			}
			if (csr5 & (RxDied | RxNoBuf)) {
				if (tp->flags & COMET_MAC_ADDR) {
					iowrite32(tp->mc_filter[0], ioaddr + 0xAC);
					iowrite32(tp->mc_filter[1], ioaddr + 0xB0);
				}
			}
			if (csr5 & RxDied) {		/* Missed a Rx frame. */
                                tp->stats.rx_missed_errors += ioread32(ioaddr + CSR8) & 0xffff;
				tp->stats.rx_errors++;
				tulip_start_rxtx(tp);
			}
			/*
			 * NB: t21142_lnk_change() does a del_timer_sync(), so be careful if this
			 * call is ever done under the spinlock
			 */
			if (csr5 & (TPLnkPass | TPLnkFail | 0x08000000)) {
				if (tp->link_change)
					(tp->link_change)(dev, csr5);
			}
			if (csr5 & SytemError) {
				int error = (csr5 >> 23) & 7;
				/* oops, we hit a PCI error.  The code produced corresponds
				 * to the reason:
				 *  0 - parity error
				 *  1 - master abort
				 *  2 - target abort
				 * Note that on parity error, we should do a software reset
				 * of the chip to get it back into a sane state (according
				 * to the 21142/3 docs that is).
				 *   -- rmk
				 */
				printk(KERN_ERR "%s: (%lu) System Error occurred (%d)\n",
					dev->name, tp->nir, error);
			}
			/* Clear all error sources, included undocumented ones! */
			iowrite32(0x0800f7ba, ioaddr + CSR5);
			oi++;
		}
		if (csr5 & TimerInt) {

			if (tulip_debug > 2)
				printk(KERN_ERR "%s: Re-enabling interrupts, %8.8x.\n",
					   dev->name, csr5);
			iowrite32(tulip_tbl[tp->chip_id].valid_intrs, ioaddr + CSR7);
			tp->ttimer = 0;
			oi++;
		}
		if (tx > maxtx || rx > maxrx || oi > maxoi) {
			if (tulip_debug > 1)
				printk(KERN_WARNING "%s: Too much work during an interrupt, "
					   "csr5=0x%8.8x. (%lu) (%d,%d,%d)\n", dev->name, csr5, tp->nir, tx, rx, oi);

                       /* Acknowledge all interrupt sources. */
                        iowrite32(0x8001ffff, ioaddr + CSR5);
                        if (tp->flags & HAS_INTR_MITIGATION) {
                     /* Josip Loncaric at ICASE did extensive experimentation
			to develop a good interrupt mitigation setting.*/
                                iowrite32(0x8b240000, ioaddr + CSR11);
                        } else if (tp->chip_id == LC82C168) {
				/* the LC82C168 doesn't have a hw timer.*/
				iowrite32(0x00, ioaddr + CSR7);
				mod_timer(&tp->timer, RUN_AT(HZ/50));
			} else {
                          /* Mask all interrupting sources, set timer to
				re-enable. */
                                iowrite32(((~csr5) & 0x0001ebef) | AbnormalIntr | TimerInt, ioaddr + CSR7);
                                iowrite32(0x0012, ioaddr + CSR11);
                        }
			break;
		}

		work_count--;
		if (work_count == 0)
			break;

		csr5 = ioread32(ioaddr + CSR5);

#ifdef CONFIG_TULIP_NAPI
		if (rxd)
			csr5 &= ~RxPollInt;
	} while ((csr5 & (TxNoBuf | 
			  TxDied | 
			  TxIntr | 
			  TimerInt |
			  /* Abnormal intr. */
			  RxDied | 
			  TxFIFOUnderflow | 
			  TxJabber | 
			  TPLnkFail |  
			  SytemError )) != 0);
#else 
	} while ((csr5 & (NormalIntr|AbnormalIntr)) != 0);

	tulip_refill_rx(dev);

	/* check if the card is in suspend mode */
	entry = tp->dirty_rx % RX_RING_SIZE;
	if (tp->rx_buffers[entry].skb == NULL) {
		if (tulip_debug > 1)
			printk(KERN_WARNING "%s: in rx suspend mode: (%lu) (tp->cur_rx = %u, ttimer = %d, rx = %d) go/stay in suspend mode\n", dev->name, tp->nir, tp->cur_rx, tp->ttimer, rx);
		if (tp->chip_id == LC82C168) {
			iowrite32(0x00, ioaddr + CSR7);
			mod_timer(&tp->timer, RUN_AT(HZ/50));
		} else {
			if (tp->ttimer == 0 || (ioread32(ioaddr + CSR11) & 0xffff) == 0) {
				if (tulip_debug > 1)
					printk(KERN_WARNING "%s: in rx suspend mode: (%lu) set timer\n", dev->name, tp->nir);
				iowrite32(tulip_tbl[tp->chip_id].valid_intrs | TimerInt,
					ioaddr + CSR7);
				iowrite32(TimerInt, ioaddr + CSR5);
				iowrite32(12, ioaddr + CSR11);
				tp->ttimer = 1;
			}
		}
	}
#endif /* CONFIG_TULIP_NAPI */

	if ((missed = ioread32(ioaddr + CSR8) & 0x1ffff)) {
		tp->stats.rx_dropped += missed & 0x10000 ? 0x10000 : missed;
	}

	if (tulip_debug > 4)
		printk(KERN_DEBUG "%s: exiting interrupt, csr5=%#4.4x.\n",
			   dev->name, ioread32(ioaddr + CSR5));

	return IRQ_HANDLED;
}