1 /* isa-skeleton.c: A network driver outline for linux.
3 * Written 1993-94 by Donald Becker.
5 * Copyright 1993 United States Government as represented by the
6 * Director, National Security Agency.
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
11 * The author may be reached as becker@scyld.com, or C/O
12 * Scyld Computing Corporation
13 * 410 Severn Ave., Suite 210
16 * This file is an outline for writing a network device driver for the
17 * the Linux operating system.
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
25 static const char *version =
26 "isa-skeleton.c:v1.51 9/24/94 Donald Becker (becker@cesdis.gsfc.nasa.gov)\n";
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
38 * Finally, keep in mind that the Linux kernel is has an API, not
39 * ABI. Proprietary object-code-only distributions are not permitted
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>
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>
60 #include <asm/system.h>
65 * The name of the card. Is used for messages and in the requests for
66 * io regions, irqs and dma channels
68 static const char* cardname = "netcard";
70 /* First, a few definitions that the brave might change. */
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};
76 /* use 0 for production, 1 for verification, >2 for debug */
80 static unsigned int net_debug = NET_DEBUG;
82 /* The number of low I/O ports used by the ethercard. */
83 #define NETCARD_IO_EXTENT 32
85 #define MY_TX_TIMEOUT ((400*HZ)/1000)
87 /* Information that need to be kept for each board. */
89 struct net_device_stats stats;
90 long open_time; /* Useless example local info. */
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.
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
105 /* Index to functions, as function prototypes. */
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);
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);
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).
130 static int __init do_netcard_probe(struct net_device *dev)
133 int base_addr = dev->base_addr;
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. */
141 for (i = 0; netcard_portlist[i]; i++) {
142 int ioaddr = netcard_portlist[i];
143 if (netcard_probe1(dev, ioaddr) == 0)
151 static void cleanup_card(struct net_device *dev)
156 #ifdef jumpered_interrupts
157 free_irq(dev->irq, dev);
159 release_region(dev->base_addr, NETCARD_IO_EXTENT);
163 struct net_device * __init netcard_probe(int unit)
165 struct net_device *dev = alloc_etherdev(sizeof(struct net_local));
169 return ERR_PTR(-ENOMEM);
171 sprintf(dev->name, "eth%d", unit);
172 netdev_boot_setup_check(dev);
174 err = do_netcard_probe(dev);
184 static const struct net_device_ops netcard_netdev_ops = {
185 .ndo_open = net_open,
186 .ndo_stop = net_close,
187 .ndo_start_xmit = net_send_packet,
188 .ndo_get_stats = net_get_stats,
189 .ndo_set_multicast_list = set_multicast_list,
190 .ndo_tx_timeout = net_tx_timeout,
191 .ndo_validate_addr = eth_validate_addr,
192 .ndo_set_mac_address = eth_mac_addr,
193 .ndo_change_mtu = eth_change_mtu,
197 * This is the real probe routine. Linux has a history of friendly device
198 * probes on the ISA bus. A good device probes avoids doing writes, and
199 * verifies that the correct device exists and functions.
201 static int __init netcard_probe1(struct net_device *dev, int ioaddr)
203 struct net_local *np;
204 static unsigned version_printed;
208 /* Grab the region so that no one else tries to probe our ioports. */
209 if (!request_region(ioaddr, NETCARD_IO_EXTENT, cardname))
213 * For ethernet adaptors the first three octets of the station address
214 * contains the manufacturer's unique code. That might be a good probe
215 * method. Ideally you would add additional checks.
217 if (inb(ioaddr + 0) != SA_ADDR0
218 || inb(ioaddr + 1) != SA_ADDR1
219 || inb(ioaddr + 2) != SA_ADDR2)
222 if (net_debug && version_printed++ == 0)
223 printk(KERN_DEBUG "%s", version);
225 printk(KERN_INFO "%s: %s found at %#3x, ", dev->name, cardname, ioaddr);
227 /* Fill in the 'dev' fields. */
228 dev->base_addr = ioaddr;
230 /* Retrieve and print the ethernet address. */
231 for (i = 0; i < 6; i++)
232 dev->dev_addr[i] = inb(ioaddr + i);
234 printk("%pM", dev->dev_addr);
237 #ifdef jumpered_interrupts
239 * If this board has jumpered interrupts, allocate the interrupt
240 * vector now. There is no point in waiting since no other device
241 * can use the interrupt, and this marks the irq as busy. Jumpered
242 * interrupts are typically not reported by the boards, and we must
243 * used autoIRQ to find them.
247 ; /* Do nothing: a user-level program will set it. */
248 else if (dev->irq < 2) { /* "Auto-IRQ" */
249 unsigned long irq_mask = probe_irq_on();
250 /* Trigger an interrupt here. */
252 dev->irq = probe_irq_off(irq_mask);
254 printk(" autoirq is %d", dev->irq);
255 } else if (dev->irq == 2)
257 * Fixup for users that don't know that IRQ 2 is really
258 * IRQ9, or don't know which one to set.
263 int irqval = request_irq(dev->irq, &net_interrupt, 0, cardname, dev);
265 printk("%s: unable to get IRQ %d (irqval=%d).\n",
266 dev->name, dev->irq, irqval);
270 #endif /* jumpered interrupt */
273 * If we use a jumpered DMA channel, that should be probed for and
274 * allocated here as well. See lance.c for an example.
277 if (request_dma(dev->dma, cardname)) {
278 printk("DMA %d allocation failed.\n", dev->dma);
281 printk(", assigned DMA %d.\n", dev->dma);
283 short dma_status, new_dma_status;
285 /* Read the DMA channel status registers. */
286 dma_status = ((inb(DMA1_STAT_REG) >> 4) & 0x0f) |
287 (inb(DMA2_STAT_REG) & 0xf0);
288 /* Trigger a DMA request, perhaps pause a bit. */
289 outw(0x1234, ioaddr + 8);
290 /* Re-read the DMA status registers. */
291 new_dma_status = ((inb(DMA1_STAT_REG) >> 4) & 0x0f) |
292 (inb(DMA2_STAT_REG) & 0xf0);
294 * Eliminate the old and floating requests,
295 * and DMA4 the cascade.
297 new_dma_status ^= dma_status;
298 new_dma_status &= ~0x10;
299 for (i = 7; i > 0; i--)
300 if (test_bit(i, &new_dma_status)) {
305 printk("DMA probe failed.\n");
308 if (request_dma(dev->dma, cardname)) {
309 printk("probed DMA %d allocation failed.\n", dev->dma);
313 #endif /* jumpered DMA */
315 np = netdev_priv(dev);
316 spin_lock_init(&np->lock);
318 dev->netdev_ops = &netcard_netdev_ops;
319 dev->watchdog_timeo = MY_TX_TIMEOUT;
321 err = register_netdev(dev);
330 #ifdef jumpered_interrupts
331 free_irq(dev->irq, dev);
334 release_region(base_addr, NETCARD_IO_EXTENT);
338 static void net_tx_timeout(struct net_device *dev)
340 struct net_local *np = netdev_priv(dev);
342 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
343 tx_done(dev) ? "IRQ conflict" : "network cable problem");
345 /* Try to restart the adaptor. */
346 chipset_init(dev, 1);
348 np->stats.tx_errors++;
350 /* If we have space available to accept new transmit
351 * requests, wake up the queueing layer. This would
352 * be the case if the chipset_init() call above just
353 * flushes out the tx queue and empties it.
355 * If instead, the tx queue is retained then the
356 * netif_wake_queue() call should be placed in the
357 * TX completion interrupt handler of the driver instead
361 netif_wake_queue(dev);
365 * Open/initialize the board. This is called (in the current kernel)
366 * sometime after booting when the 'ifconfig' program is run.
368 * This routine should set everything up anew at each open, even
369 * registers that "should" only need to be set once at boot, so that
370 * there is non-reboot way to recover if something goes wrong.
373 net_open(struct net_device *dev)
375 struct net_local *np = netdev_priv(dev);
376 int ioaddr = dev->base_addr;
378 * This is used if the interrupt line can turned off (shared).
379 * See 3c503.c for an example of selecting the IRQ at config-time.
381 if (request_irq(dev->irq, &net_interrupt, 0, cardname, dev)) {
385 * Always allocate the DMA channel after the IRQ,
386 * and clean up on failure.
388 if (request_dma(dev->dma, cardname)) {
389 free_irq(dev->irq, dev);
393 /* Reset the hardware here. Don't forget to set the station address. */
394 chipset_init(dev, 1);
396 np->open_time = jiffies;
398 /* We are now ready to accept transmit requeusts from
399 * the queueing layer of the networking.
401 netif_start_queue(dev);
406 /* This will only be invoked if your driver is _not_ in XOFF state.
407 * What this means is that you need not check it, and that this
408 * invariant will hold if you make sure that the netif_*_queue()
409 * calls are done at the proper times.
411 static int net_send_packet(struct sk_buff *skb, struct net_device *dev)
413 struct net_local *np = netdev_priv(dev);
414 int ioaddr = dev->base_addr;
415 short length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
416 unsigned char *buf = skb->data;
418 /* If some error occurs while trying to transmit this
419 * packet, you should return '1' from this function.
420 * In such a case you _may not_ do anything to the
421 * SKB, it is still owned by the network queueing
422 * layer when an error is returned. This means you
423 * may not modify any SKB fields, you may not free
428 /* This is the most common case for modern hardware.
429 * The spinlock protects this code from the TX complete
430 * hardware interrupt handler. Queue flow control is
431 * thus managed under this lock as well.
433 spin_lock_irq(&np->lock);
435 add_to_tx_ring(np, skb, length);
436 dev->trans_start = jiffies;
438 /* If we just used up the very last entry in the
439 * TX ring on this device, tell the queueing
440 * layer to send no more.
443 netif_stop_queue(dev);
445 /* When the TX completion hw interrupt arrives, this
446 * is when the transmit statistics are updated.
449 spin_unlock_irq(&np->lock);
451 /* This is the case for older hardware which takes
452 * a single transmit buffer at a time, and it is
453 * just written to the device via PIO.
455 * No spin locking is needed since there is no TX complete
456 * event. If by chance your card does have a TX complete
457 * hardware IRQ then you may need to utilize np->lock here.
459 hardware_send_packet(ioaddr, buf, length);
460 np->stats.tx_bytes += skb->len;
462 dev->trans_start = jiffies;
464 /* You might need to clean up and record Tx statistics here. */
465 if (inw(ioaddr) == /*RU*/81)
466 np->stats.tx_aborted_errors++;
474 /* This handles TX complete events posted by the device
477 void net_tx(struct net_device *dev)
479 struct net_local *np = netdev_priv(dev);
482 /* This protects us from concurrent execution of
483 * our dev->hard_start_xmit function above.
485 spin_lock(&np->lock);
488 while (tx_entry_is_sent(np, entry)) {
489 struct sk_buff *skb = np->skbs[entry];
491 np->stats.tx_bytes += skb->len;
492 dev_kfree_skb_irq (skb);
494 entry = next_tx_entry(np, entry);
498 /* If we had stopped the queue due to a "tx full"
499 * condition, and space has now been made available,
502 if (netif_queue_stopped(dev) && ! tx_full(dev))
503 netif_wake_queue(dev);
505 spin_unlock(&np->lock);
510 * The typical workload of the driver:
511 * Handle the network interface interrupts.
513 static irqreturn_t net_interrupt(int irq, void *dev_id)
515 struct net_device *dev = dev_id;
516 struct net_local *np;
520 ioaddr = dev->base_addr;
522 np = netdev_priv(dev);
523 status = inw(ioaddr + 0);
529 if (status & RX_INTR) {
530 /* Got a packet(s). */
534 if (status & TX_INTR) {
535 /* Transmit complete. */
537 np->stats.tx_packets++;
538 netif_wake_queue(dev);
541 if (status & COUNTERS_INTR) {
542 /* Increment the appropriate 'localstats' field. */
543 np->stats.tx_window_errors++;
546 return IRQ_RETVAL(handled);
549 /* We have a good packet(s), get it/them out of the buffers. */
551 net_rx(struct net_device *dev)
553 struct net_local *lp = netdev_priv(dev);
554 int ioaddr = dev->base_addr;
558 int status = inw(ioaddr);
559 int pkt_len = inw(ioaddr);
561 if (pkt_len == 0) /* Read all the frames? */
562 break; /* Done for now */
564 if (status & 0x40) { /* There was an error. */
565 lp->stats.rx_errors++;
566 if (status & 0x20) lp->stats.rx_frame_errors++;
567 if (status & 0x10) lp->stats.rx_over_errors++;
568 if (status & 0x08) lp->stats.rx_crc_errors++;
569 if (status & 0x04) lp->stats.rx_fifo_errors++;
571 /* Malloc up new buffer. */
574 lp->stats.rx_bytes+=pkt_len;
576 skb = dev_alloc_skb(pkt_len);
578 printk(KERN_NOTICE "%s: Memory squeeze, dropping packet.\n",
580 lp->stats.rx_dropped++;
585 /* 'skb->data' points to the start of sk_buff data area. */
586 memcpy(skb_put(skb,pkt_len), (void*)dev->rmem_start,
589 insw(ioaddr, skb->data, (pkt_len + 1) >> 1);
592 lp->stats.rx_packets++;
593 lp->stats.rx_bytes += pkt_len;
595 } while (--boguscount);
600 /* The inverse routine to net_open(). */
602 net_close(struct net_device *dev)
604 struct net_local *lp = netdev_priv(dev);
605 int ioaddr = dev->base_addr;
609 netif_stop_queue(dev);
611 /* Flush the Tx and disable Rx here. */
613 disable_dma(dev->dma);
615 /* If not IRQ or DMA jumpered, free up the line. */
616 outw(0x00, ioaddr+0); /* Release the physical interrupt line. */
618 free_irq(dev->irq, dev);
621 /* Update the statistics here. */
628 * Get the current statistics.
629 * This may be called with the card open or closed.
631 static struct net_device_stats *net_get_stats(struct net_device *dev)
633 struct net_local *lp = netdev_priv(dev);
634 short ioaddr = dev->base_addr;
636 /* Update the statistics from the device registers. */
637 lp->stats.rx_missed_errors = inw(ioaddr+1);
642 * Set or clear the multicast filter for this adaptor.
643 * num_addrs == -1 Promiscuous mode, receive all packets
644 * num_addrs == 0 Normal mode, clear multicast list
645 * num_addrs > 0 Multicast mode, receive normal and MC packets,
646 * and do best-effort filtering.
649 set_multicast_list(struct net_device *dev)
651 short ioaddr = dev->base_addr;
652 if (dev->flags&IFF_PROMISC)
654 /* Enable promiscuous mode */
655 outw(MULTICAST|PROMISC, ioaddr);
657 else if((dev->flags&IFF_ALLMULTI) || dev->mc_count > HW_MAX_ADDRS)
659 /* Disable promiscuous mode, use normal mode. */
660 hardware_set_filter(NULL);
662 outw(MULTICAST, ioaddr);
664 else if(dev->mc_count)
666 /* Walk the address list, and load the filter */
667 hardware_set_filter(dev->mc_list);
669 outw(MULTICAST, ioaddr);
677 static struct net_device *this_device;
678 static int io = 0x300;
682 MODULE_LICENSE("GPL");
684 int init_module(void)
686 struct net_device *dev;
690 printk(KERN_WARNING "%s: You shouldn't use auto-probing with insmod!\n",
692 dev = alloc_etherdev(sizeof(struct net_local));
696 /* Copy the parameters from insmod into the device structure. */
700 dev->mem_start = mem;
701 if (do_netcard_probe(dev) == 0) {
712 unregister_netdev(this_device);
713 cleanup_card(this_device);
714 free_netdev(this_device);