1 /* isa-skeleton.c: A network driver outline for linux.
2 *
3 * Written 1993-94 by Donald Becker.
4 *
5 * Copyright 1993 United States Government as represented by the
6 * Director, National Security Agency.
7 *
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
10 *
11 * The author may be reached as becker@scyld.com, or C/O
12 * Scyld Computing Corporation
13 * 410 Severn Ave., Suite 210
14 * Annapolis MD 21403
15 *
16 * This file is an outline for writing a network device driver for the
17 * the Linux operating system.
18 *
19 * To write (or understand) a driver, have a look at the "loopback.c" file to
20 * get a feel of what is going on, and then use the code below as a skeleton
21 * for the new driver.
22 *
23 */
24
25 static const char *version =
26 "isa-skeleton.c:v1.51 9/24/94 Donald Becker (becker@cesdis.gsfc.nasa.gov)\n";
27
28 /*
29 * Sources:
30 * List your sources of programming information to document that
31 * the driver is your own creation, and give due credit to others
32 * that contributed to the work. Remember that GNU project code
33 * cannot use proprietary or trade secret information. Interface
34 * definitions are generally considered non-copyrightable to the
35 * extent that the same names and structures must be used to be
36 * compatible.
37 *
38 * Finally, keep in mind that the Linux kernel is has an API, not
39 * ABI. Proprietary object-code-only distributions are not permitted
40 * under the GPL.
41 */
42
43 #include <linux/module.h>
44 #include <linux/kernel.h>
45 #include <linux/types.h>
46 #include <linux/fcntl.h>
47 #include <linux/interrupt.h>
48 #include <linux/ioport.h>
49 #include <linux/in.h>
50 #include <linux/slab.h>
51 #include <linux/string.h>
52 #include <linux/spinlock.h>
53 #include <linux/errno.h>
54 #include <linux/init.h>
55 #include <linux/netdevice.h>
56 #include <linux/etherdevice.h>
57 #include <linux/skbuff.h>
58 #include <linux/bitops.h>
59
60 #include <asm/system.h>
61 #include <asm/io.h>
62 #include <asm/dma.h>
63
64 /*
65 * The name of the card. Is used for messages and in the requests for
66 * io regions, irqs and dma channels
67 */
68 static const char* cardname = "netcard";
69
70 /* First, a few definitions that the brave might change. */
71
72 /* A zero-terminated list of I/O addresses to be probed. */
73 static unsigned int netcard_portlist[] __initdata =
74 { 0x200, 0x240, 0x280, 0x2C0, 0x300, 0x320, 0x340, 0};
75
76 /* use 0 for production, 1 for verification, >2 for debug */
77 #ifndef NET_DEBUG
78 #define NET_DEBUG 2
79 #endif
80 static unsigned int net_debug = NET_DEBUG;
81
82 /* The number of low I/O ports used by the ethercard. */
83 #define NETCARD_IO_EXTENT 32
84
85 #define MY_TX_TIMEOUT ((400*HZ)/1000)
86
87 /* Information that need to be kept for each board. */
88 struct net_local {
89 struct net_device_stats stats;
90 long open_time; /* Useless example local info. */
91
92 /* Tx control lock. This protects the transmit buffer ring
93 * state along with the "tx full" state of the driver. This
94 * means all netif_queue flow control actions are protected
95 * by this lock as well.
96 */
97 spinlock_t lock;
98 };
99
100 /* The station (ethernet) address prefix, used for IDing the board. */
101 #define SA_ADDR0 0x00
102 #define SA_ADDR1 0x42
103 #define SA_ADDR2 0x65
104
105 /* Index to functions, as function prototypes. */
106
107 static int netcard_probe1(struct net_device *dev, int ioaddr);
108 static int net_open(struct net_device *dev);
109 static int net_send_packet(struct sk_buff *skb, struct net_device *dev);
110 static irqreturn_t net_interrupt(int irq, void *dev_id);
111 static void net_rx(struct net_device *dev);
112 static int net_close(struct net_device *dev);
113 static struct net_device_stats *net_get_stats(struct net_device *dev);
114 static void set_multicast_list(struct net_device *dev);
115 static void net_tx_timeout(struct net_device *dev);
116
117
118 /* Example routines you must write ;->. */
119 #define tx_done(dev) 1
120 static void hardware_send_packet(short ioaddr, char *buf, int length);
121 static void chipset_init(struct net_device *dev, int startp);
122
123 /*
124 * Check for a network adaptor of this type, and return '0' iff one exists.
125 * If dev->base_addr == 0, probe all likely locations.
126 * If dev->base_addr == 1, always return failure.
127 * If dev->base_addr == 2, allocate space for the device and return success
128 * (detachable devices only).
129 */
do_netcard_probe(struct net_device * dev)130 static int __init do_netcard_probe(struct net_device *dev)
131 {
132 int i;
133 int base_addr = dev->base_addr;
134 int irq = dev->irq;
135
136 if (base_addr > 0x1ff) /* Check a single specified location. */
137 return netcard_probe1(dev, base_addr);
138 else if (base_addr != 0) /* Don't probe at all. */
139 return -ENXIO;
140
141 for (i = 0; netcard_portlist[i]; i++) {
142 int ioaddr = netcard_portlist[i];
143 if (netcard_probe1(dev, ioaddr) == 0)
144 return 0;
145 dev->irq = irq;
146 }
147
148 return -ENODEV;
149 }
150
cleanup_card(struct net_device * dev)151 static void cleanup_card(struct net_device *dev)
152 {
153 #ifdef jumpered_dma
154 free_dma(dev->dma);
155 #endif
156 #ifdef jumpered_interrupts
157 free_irq(dev->irq, dev);
158 #endif
159 release_region(dev->base_addr, NETCARD_IO_EXTENT);
160 }
161
162 #ifndef MODULE
netcard_probe(int unit)163 struct net_device * __init netcard_probe(int unit)
164 {
165 struct net_device *dev = alloc_etherdev(sizeof(struct net_local));
166 int err;
167
168 if (!dev)
169 return ERR_PTR(-ENOMEM);
170
171 sprintf(dev->name, "eth%d", unit);
172 netdev_boot_setup_check(dev);
173
174 err = do_netcard_probe(dev);
175 if (err)
176 goto out;
177 return dev;
178 out:
179 free_netdev(dev);
180 return ERR_PTR(err);
181 }
182 #endif
183
184 /*
185 * This is the real probe routine. Linux has a history of friendly device
186 * probes on the ISA bus. A good device probes avoids doing writes, and
187 * verifies that the correct device exists and functions.
188 */
netcard_probe1(struct net_device * dev,int ioaddr)189 static int __init netcard_probe1(struct net_device *dev, int ioaddr)
190 {
191 struct net_local *np;
192 static unsigned version_printed;
193 int i;
194 int err = -ENODEV;
195
196 /* Grab the region so that no one else tries to probe our ioports. */
197 if (!request_region(ioaddr, NETCARD_IO_EXTENT, cardname))
198 return -EBUSY;
199
200 /*
201 * For ethernet adaptors the first three octets of the station address
202 * contains the manufacturer's unique code. That might be a good probe
203 * method. Ideally you would add additional checks.
204 */
205 if (inb(ioaddr + 0) != SA_ADDR0
206 || inb(ioaddr + 1) != SA_ADDR1
207 || inb(ioaddr + 2) != SA_ADDR2)
208 goto out;
209
210 if (net_debug && version_printed++ == 0)
211 printk(KERN_DEBUG "%s", version);
212
213 printk(KERN_INFO "%s: %s found at %#3x, ", dev->name, cardname, ioaddr);
214
215 /* Fill in the 'dev' fields. */
216 dev->base_addr = ioaddr;
217
218 /* Retrieve and print the ethernet address. */
219 for (i = 0; i < 6; i++)
220 dev->dev_addr[i] = inb(ioaddr + i);
221
222 printk("%pM", dev->dev_addr);
223
224 err = -EAGAIN;
225 #ifdef jumpered_interrupts
226 /*
227 * If this board has jumpered interrupts, allocate the interrupt
228 * vector now. There is no point in waiting since no other device
229 * can use the interrupt, and this marks the irq as busy. Jumpered
230 * interrupts are typically not reported by the boards, and we must
231 * used autoIRQ to find them.
232 */
233
234 if (dev->irq == -1)
235 ; /* Do nothing: a user-level program will set it. */
236 else if (dev->irq < 2) { /* "Auto-IRQ" */
237 unsigned long irq_mask = probe_irq_on();
238 /* Trigger an interrupt here. */
239
240 dev->irq = probe_irq_off(irq_mask);
241 if (net_debug >= 2)
242 printk(" autoirq is %d", dev->irq);
243 } else if (dev->irq == 2)
244 /*
245 * Fixup for users that don't know that IRQ 2 is really
246 * IRQ9, or don't know which one to set.
247 */
248 dev->irq = 9;
249
250 {
251 int irqval = request_irq(dev->irq, &net_interrupt, 0, cardname, dev);
252 if (irqval) {
253 printk("%s: unable to get IRQ %d (irqval=%d).\n",
254 dev->name, dev->irq, irqval);
255 goto out;
256 }
257 }
258 #endif /* jumpered interrupt */
259 #ifdef jumpered_dma
260 /*
261 * If we use a jumpered DMA channel, that should be probed for and
262 * allocated here as well. See lance.c for an example.
263 */
264 if (dev->dma == 0) {
265 if (request_dma(dev->dma, cardname)) {
266 printk("DMA %d allocation failed.\n", dev->dma);
267 goto out1;
268 } else
269 printk(", assigned DMA %d.\n", dev->dma);
270 } else {
271 short dma_status, new_dma_status;
272
273 /* Read the DMA channel status registers. */
274 dma_status = ((inb(DMA1_STAT_REG) >> 4) & 0x0f) |
275 (inb(DMA2_STAT_REG) & 0xf0);
276 /* Trigger a DMA request, perhaps pause a bit. */
277 outw(0x1234, ioaddr + 8);
278 /* Re-read the DMA status registers. */
279 new_dma_status = ((inb(DMA1_STAT_REG) >> 4) & 0x0f) |
280 (inb(DMA2_STAT_REG) & 0xf0);
281 /*
282 * Eliminate the old and floating requests,
283 * and DMA4 the cascade.
284 */
285 new_dma_status ^= dma_status;
286 new_dma_status &= ~0x10;
287 for (i = 7; i > 0; i--)
288 if (test_bit(i, &new_dma_status)) {
289 dev->dma = i;
290 break;
291 }
292 if (i <= 0) {
293 printk("DMA probe failed.\n");
294 goto out1;
295 }
296 if (request_dma(dev->dma, cardname)) {
297 printk("probed DMA %d allocation failed.\n", dev->dma);
298 goto out1;
299 }
300 }
301 #endif /* jumpered DMA */
302
303 np = netdev_priv(dev);
304 spin_lock_init(&np->lock);
305
306 dev->open = net_open;
307 dev->stop = net_close;
308 dev->hard_start_xmit = net_send_packet;
309 dev->get_stats = net_get_stats;
310 dev->set_multicast_list = &set_multicast_list;
311
312 dev->tx_timeout = &net_tx_timeout;
313 dev->watchdog_timeo = MY_TX_TIMEOUT;
314
315 err = register_netdev(dev);
316 if (err)
317 goto out2;
318 return 0;
319 out2:
320 #ifdef jumpered_dma
321 free_dma(dev->dma);
322 #endif
323 out1:
324 #ifdef jumpered_interrupts
325 free_irq(dev->irq, dev);
326 #endif
327 out:
328 release_region(base_addr, NETCARD_IO_EXTENT);
329 return err;
330 }
331
net_tx_timeout(struct net_device * dev)332 static void net_tx_timeout(struct net_device *dev)
333 {
334 struct net_local *np = netdev_priv(dev);
335
336 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
337 tx_done(dev) ? "IRQ conflict" : "network cable problem");
338
339 /* Try to restart the adaptor. */
340 chipset_init(dev, 1);
341
342 np->stats.tx_errors++;
343
344 /* If we have space available to accept new transmit
345 * requests, wake up the queueing layer. This would
346 * be the case if the chipset_init() call above just
347 * flushes out the tx queue and empties it.
348 *
349 * If instead, the tx queue is retained then the
350 * netif_wake_queue() call should be placed in the
351 * TX completion interrupt handler of the driver instead
352 * of here.
353 */
354 if (!tx_full(dev))
355 netif_wake_queue(dev);
356 }
357
358 /*
359 * Open/initialize the board. This is called (in the current kernel)
360 * sometime after booting when the 'ifconfig' program is run.
361 *
362 * This routine should set everything up anew at each open, even
363 * registers that "should" only need to be set once at boot, so that
364 * there is non-reboot way to recover if something goes wrong.
365 */
366 static int
net_open(struct net_device * dev)367 net_open(struct net_device *dev)
368 {
369 struct net_local *np = netdev_priv(dev);
370 int ioaddr = dev->base_addr;
371 /*
372 * This is used if the interrupt line can turned off (shared).
373 * See 3c503.c for an example of selecting the IRQ at config-time.
374 */
375 if (request_irq(dev->irq, &net_interrupt, 0, cardname, dev)) {
376 return -EAGAIN;
377 }
378 /*
379 * Always allocate the DMA channel after the IRQ,
380 * and clean up on failure.
381 */
382 if (request_dma(dev->dma, cardname)) {
383 free_irq(dev->irq, dev);
384 return -EAGAIN;
385 }
386
387 /* Reset the hardware here. Don't forget to set the station address. */
388 chipset_init(dev, 1);
389 outb(0x00, ioaddr);
390 np->open_time = jiffies;
391
392 /* We are now ready to accept transmit requeusts from
393 * the queueing layer of the networking.
394 */
395 netif_start_queue(dev);
396
397 return 0;
398 }
399
400 /* This will only be invoked if your driver is _not_ in XOFF state.
401 * What this means is that you need not check it, and that this
402 * invariant will hold if you make sure that the netif_*_queue()
403 * calls are done at the proper times.
404 */
net_send_packet(struct sk_buff * skb,struct net_device * dev)405 static int net_send_packet(struct sk_buff *skb, struct net_device *dev)
406 {
407 struct net_local *np = netdev_priv(dev);
408 int ioaddr = dev->base_addr;
409 short length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
410 unsigned char *buf = skb->data;
411
412 /* If some error occurs while trying to transmit this
413 * packet, you should return '1' from this function.
414 * In such a case you _may not_ do anything to the
415 * SKB, it is still owned by the network queueing
416 * layer when an error is returned. This means you
417 * may not modify any SKB fields, you may not free
418 * the SKB, etc.
419 */
420
421 #if TX_RING
422 /* This is the most common case for modern hardware.
423 * The spinlock protects this code from the TX complete
424 * hardware interrupt handler. Queue flow control is
425 * thus managed under this lock as well.
426 */
427 spin_lock_irq(&np->lock);
428
429 add_to_tx_ring(np, skb, length);
430 dev->trans_start = jiffies;
431
432 /* If we just used up the very last entry in the
433 * TX ring on this device, tell the queueing
434 * layer to send no more.
435 */
436 if (tx_full(dev))
437 netif_stop_queue(dev);
438
439 /* When the TX completion hw interrupt arrives, this
440 * is when the transmit statistics are updated.
441 */
442
443 spin_unlock_irq(&np->lock);
444 #else
445 /* This is the case for older hardware which takes
446 * a single transmit buffer at a time, and it is
447 * just written to the device via PIO.
448 *
449 * No spin locking is needed since there is no TX complete
450 * event. If by chance your card does have a TX complete
451 * hardware IRQ then you may need to utilize np->lock here.
452 */
453 hardware_send_packet(ioaddr, buf, length);
454 np->stats.tx_bytes += skb->len;
455
456 dev->trans_start = jiffies;
457
458 /* You might need to clean up and record Tx statistics here. */
459 if (inw(ioaddr) == /*RU*/81)
460 np->stats.tx_aborted_errors++;
461 dev_kfree_skb (skb);
462 #endif
463
464 return 0;
465 }
466
467 #if TX_RING
468 /* This handles TX complete events posted by the device
469 * via interrupts.
470 */
net_tx(struct net_device * dev)471 void net_tx(struct net_device *dev)
472 {
473 struct net_local *np = netdev_priv(dev);
474 int entry;
475
476 /* This protects us from concurrent execution of
477 * our dev->hard_start_xmit function above.
478 */
479 spin_lock(&np->lock);
480
481 entry = np->tx_old;
482 while (tx_entry_is_sent(np, entry)) {
483 struct sk_buff *skb = np->skbs[entry];
484
485 np->stats.tx_bytes += skb->len;
486 dev_kfree_skb_irq (skb);
487
488 entry = next_tx_entry(np, entry);
489 }
490 np->tx_old = entry;
491
492 /* If we had stopped the queue due to a "tx full"
493 * condition, and space has now been made available,
494 * wake up the queue.
495 */
496 if (netif_queue_stopped(dev) && ! tx_full(dev))
497 netif_wake_queue(dev);
498
499 spin_unlock(&np->lock);
500 }
501 #endif
502
503 /*
504 * The typical workload of the driver:
505 * Handle the network interface interrupts.
506 */
net_interrupt(int irq,void * dev_id)507 static irqreturn_t net_interrupt(int irq, void *dev_id)
508 {
509 struct net_device *dev = dev_id;
510 struct net_local *np;
511 int ioaddr, status;
512 int handled = 0;
513
514 ioaddr = dev->base_addr;
515
516 np = netdev_priv(dev);
517 status = inw(ioaddr + 0);
518
519 if (status == 0)
520 goto out;
521 handled = 1;
522
523 if (status & RX_INTR) {
524 /* Got a packet(s). */
525 net_rx(dev);
526 }
527 #if TX_RING
528 if (status & TX_INTR) {
529 /* Transmit complete. */
530 net_tx(dev);
531 np->stats.tx_packets++;
532 netif_wake_queue(dev);
533 }
534 #endif
535 if (status & COUNTERS_INTR) {
536 /* Increment the appropriate 'localstats' field. */
537 np->stats.tx_window_errors++;
538 }
539 out:
540 return IRQ_RETVAL(handled);
541 }
542
543 /* We have a good packet(s), get it/them out of the buffers. */
544 static void
net_rx(struct net_device * dev)545 net_rx(struct net_device *dev)
546 {
547 struct net_local *lp = netdev_priv(dev);
548 int ioaddr = dev->base_addr;
549 int boguscount = 10;
550
551 do {
552 int status = inw(ioaddr);
553 int pkt_len = inw(ioaddr);
554
555 if (pkt_len == 0) /* Read all the frames? */
556 break; /* Done for now */
557
558 if (status & 0x40) { /* There was an error. */
559 lp->stats.rx_errors++;
560 if (status & 0x20) lp->stats.rx_frame_errors++;
561 if (status & 0x10) lp->stats.rx_over_errors++;
562 if (status & 0x08) lp->stats.rx_crc_errors++;
563 if (status & 0x04) lp->stats.rx_fifo_errors++;
564 } else {
565 /* Malloc up new buffer. */
566 struct sk_buff *skb;
567
568 lp->stats.rx_bytes+=pkt_len;
569
570 skb = dev_alloc_skb(pkt_len);
571 if (skb == NULL) {
572 printk(KERN_NOTICE "%s: Memory squeeze, dropping packet.\n",
573 dev->name);
574 lp->stats.rx_dropped++;
575 break;
576 }
577 skb->dev = dev;
578
579 /* 'skb->data' points to the start of sk_buff data area. */
580 memcpy(skb_put(skb,pkt_len), (void*)dev->rmem_start,
581 pkt_len);
582 /* or */
583 insw(ioaddr, skb->data, (pkt_len + 1) >> 1);
584
585 netif_rx(skb);
586 lp->stats.rx_packets++;
587 lp->stats.rx_bytes += pkt_len;
588 }
589 } while (--boguscount);
590
591 return;
592 }
593
594 /* The inverse routine to net_open(). */
595 static int
net_close(struct net_device * dev)596 net_close(struct net_device *dev)
597 {
598 struct net_local *lp = netdev_priv(dev);
599 int ioaddr = dev->base_addr;
600
601 lp->open_time = 0;
602
603 netif_stop_queue(dev);
604
605 /* Flush the Tx and disable Rx here. */
606
607 disable_dma(dev->dma);
608
609 /* If not IRQ or DMA jumpered, free up the line. */
610 outw(0x00, ioaddr+0); /* Release the physical interrupt line. */
611
612 free_irq(dev->irq, dev);
613 free_dma(dev->dma);
614
615 /* Update the statistics here. */
616
617 return 0;
618
619 }
620
621 /*
622 * Get the current statistics.
623 * This may be called with the card open or closed.
624 */
net_get_stats(struct net_device * dev)625 static struct net_device_stats *net_get_stats(struct net_device *dev)
626 {
627 struct net_local *lp = netdev_priv(dev);
628 short ioaddr = dev->base_addr;
629
630 /* Update the statistics from the device registers. */
631 lp->stats.rx_missed_errors = inw(ioaddr+1);
632 return &lp->stats;
633 }
634
635 /*
636 * Set or clear the multicast filter for this adaptor.
637 * num_addrs == -1 Promiscuous mode, receive all packets
638 * num_addrs == 0 Normal mode, clear multicast list
639 * num_addrs > 0 Multicast mode, receive normal and MC packets,
640 * and do best-effort filtering.
641 */
642 static void
set_multicast_list(struct net_device * dev)643 set_multicast_list(struct net_device *dev)
644 {
645 short ioaddr = dev->base_addr;
646 if (dev->flags&IFF_PROMISC)
647 {
648 /* Enable promiscuous mode */
649 outw(MULTICAST|PROMISC, ioaddr);
650 }
651 else if((dev->flags&IFF_ALLMULTI) || dev->mc_count > HW_MAX_ADDRS)
652 {
653 /* Disable promiscuous mode, use normal mode. */
654 hardware_set_filter(NULL);
655
656 outw(MULTICAST, ioaddr);
657 }
658 else if(dev->mc_count)
659 {
660 /* Walk the address list, and load the filter */
661 hardware_set_filter(dev->mc_list);
662
663 outw(MULTICAST, ioaddr);
664 }
665 else
666 outw(0, ioaddr);
667 }
668
669 #ifdef MODULE
670
671 static struct net_device *this_device;
672 static int io = 0x300;
673 static int irq;
674 static int dma;
675 static int mem;
676 MODULE_LICENSE("GPL");
677
init_module(void)678 int init_module(void)
679 {
680 struct net_device *dev;
681 int result;
682
683 if (io == 0)
684 printk(KERN_WARNING "%s: You shouldn't use auto-probing with insmod!\n",
685 cardname);
686 dev = alloc_etherdev(sizeof(struct net_local));
687 if (!dev)
688 return -ENOMEM;
689
690 /* Copy the parameters from insmod into the device structure. */
691 dev->base_addr = io;
692 dev->irq = irq;
693 dev->dma = dma;
694 dev->mem_start = mem;
695 if (do_netcard_probe(dev) == 0) {
696 this_device = dev;
697 return 0;
698 }
699 free_netdev(dev);
700 return -ENXIO;
701 }
702
703 void
cleanup_module(void)704 cleanup_module(void)
705 {
706 unregister_netdev(this_device);
707 cleanup_card(this_device);
708 free_netdev(this_device);
709 }
710
711 #endif /* MODULE */
712