1 /* 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 Public License, incorporated herein by reference.
11 * The author may be reached as becker@CESDIS.gsfc.nasa.gov, or C/O
12 * Center of Excellence in Space Data and Information Sciences
13 * Code 930.5, Goddard Space Flight Center, Greenbelt MD 20771
15 * This file is an outline for writing a network device driver for the
16 * the Linux operating system.
18 * To write (or understand) a driver, have a look at the "loopback.c" file to
19 * get a feel of what is going on, and then use the code below as a skeleton
24 static const char *version
=
25 "skeleton.c:v1.51 9/24/94 Donald Becker (becker@cesdis.gsfc.nasa.gov)\n";
29 * List your sources of programming information to document that
30 * the driver is your own creation, and give due credit to others
31 * that contributed to the work. Remember that GNU project code
32 * cannot use proprietary or trade secret information. Interface
33 * definitions are generally considered non-copyrightable to the
34 * extent that the same names and structures must be used to be
37 * Finally, keep in mind that the Linux kernel is has an API, not
38 * ABI. Proprietary object-code-only distributions are not permitted
42 #include <linux/module.h>
44 #include <linux/kernel.h>
45 #include <linux/sched.h>
46 #include <linux/types.h>
47 #include <linux/fcntl.h>
48 #include <linux/interrupt.h>
49 #include <linux/ptrace.h>
50 #include <linux/ioport.h>
52 #include <linux/malloc.h>
53 #include <linux/string.h>
54 #include <asm/system.h>
55 #include <asm/bitops.h>
56 #include <linux/spinlock.h>
59 #include <linux/errno.h>
60 #include <linux/init.h>
62 #include <linux/netdevice.h>
63 #include <linux/etherdevice.h>
64 #include <linux/skbuff.h>
67 * The name of the card. Is used for messages and in the requests for
68 * io regions, irqs and dma channels
70 static const char* cardname
= "netcard";
72 /* First, a few definitions that the brave might change. */
74 /* A zero-terminated list of I/O addresses to be probed. */
75 static unsigned int netcard_portlist
[] __initdata
=
76 { 0x200, 0x240, 0x280, 0x2C0, 0x300, 0x320, 0x340, 0};
78 /* use 0 for production, 1 for verification, >2 for debug */
82 static unsigned int net_debug
= NET_DEBUG
;
84 /* The number of low I/O ports used by the ethercard. */
85 #define NETCARD_IO_EXTENT 32
87 #define MY_TX_TIMEOUT ((400*HZ)/1000)
89 /* Information that need to be kept for each board. */
91 struct net_device_stats stats
;
92 long open_time
; /* Useless example local info. */
94 /* Tx control lock. This protects the transmit buffer ring
95 * state along with the "tx full" state of the driver. This
96 * means all netif_queue flow control actions are protected
97 * by this lock as well.
102 /* The station (ethernet) address prefix, used for IDing the board. */
103 #define SA_ADDR0 0x00
104 #define SA_ADDR1 0x42
105 #define SA_ADDR2 0x65
107 /* Index to functions, as function prototypes. */
109 extern int netcard_probe(struct net_device
*dev
);
111 static int netcard_probe1(struct net_device
*dev
, int ioaddr
);
112 static int net_open(struct net_device
*dev
);
113 static int net_send_packet(struct sk_buff
*skb
, struct net_device
*dev
);
114 static void net_interrupt(int irq
, void *dev_id
, struct pt_regs
*regs
);
115 static void net_rx(struct net_device
*dev
);
116 static int net_close(struct net_device
*dev
);
117 static struct net_device_stats
*net_get_stats(struct net_device
*dev
);
118 static void set_multicast_list(struct net_device
*dev
);
119 static void net_tx_timeout(struct net_device
*dev
);
122 /* Example routines you must write ;->. */
123 #define tx_done(dev) 1
124 extern void hardware_send_packet(short ioaddr
, char *buf
, int length
);
125 extern void chipset_init(struct net_device
*dev
, int startp
);
128 * Check for a network adaptor of this type, and return '0' iff one exists.
129 * If dev->base_addr == 0, probe all likely locations.
130 * If dev->base_addr == 1, always return failure.
131 * If dev->base_addr == 2, allocate space for the device and return success
132 * (detachable devices only).
136 * Support for an alternate probe manager,
137 * which will eliminate the boilerplate below.
139 struct netdev_entry netcard_drv
=
140 {cardname
, netcard_probe1
, NETCARD_IO_EXTENT
, netcard_portlist
};
143 netcard_probe(struct net_device
*dev
)
146 int base_addr
= dev
? dev
->base_addr
: 0;
148 if (base_addr
> 0x1ff) /* Check a single specified location. */
149 return netcard_probe1(dev
, base_addr
);
150 else if (base_addr
!= 0) /* Don't probe at all. */
153 for (i
= 0; netcard_portlist
[i
]; i
++) {
154 int ioaddr
= netcard_portlist
[i
];
155 if (check_region(ioaddr
, NETCARD_IO_EXTENT
))
157 if (netcard_probe1(dev
, ioaddr
) == 0)
166 * This is the real probe routine. Linux has a history of friendly device
167 * probes on the ISA bus. A good device probes avoids doing writes, and
168 * verifies that the correct device exists and functions.
170 static int __init
netcard_probe1(struct net_device
*dev
, int ioaddr
)
172 struct net_local
*np
;
173 static unsigned version_printed
= 0;
177 * For ethernet adaptors the first three octets of the station address
178 * contains the manufacturer's unique code. That might be a good probe
179 * method. Ideally you would add additional checks.
181 if (inb(ioaddr
+ 0) != SA_ADDR0
182 || inb(ioaddr
+ 1) != SA_ADDR1
183 || inb(ioaddr
+ 2) != SA_ADDR2
) {
187 /* Allocate a new 'dev' if needed. */
190 * Don't allocate the private data here, it is done later
191 * This makes it easier to free the memory when this driver
192 * is used as a module.
194 dev
= init_etherdev(0, 0);
199 if (net_debug
&& version_printed
++ == 0)
200 printk(KERN_DEBUG
"%s", version
);
202 printk(KERN_INFO
"%s: %s found at %#3x, ", dev
->name
, cardname
, ioaddr
);
204 /* Fill in the 'dev' fields. */
205 dev
->base_addr
= ioaddr
;
207 /* Retrieve and print the ethernet address. */
208 for (i
= 0; i
< 6; i
++)
209 printk(" %2.2x", dev
->dev_addr
[i
] = inb(ioaddr
+ i
));
211 #ifdef jumpered_interrupts
213 * If this board has jumpered interrupts, allocate the interrupt
214 * vector now. There is no point in waiting since no other device
215 * can use the interrupt, and this marks the irq as busy. Jumpered
216 * interrupts are typically not reported by the boards, and we must
217 * used autoIRQ to find them.
221 ; /* Do nothing: a user-level program will set it. */
222 else if (dev
->irq
< 2) { /* "Auto-IRQ" */
224 /* Trigger an interrupt here. */
226 dev
->irq
= autoirq_report(0);
228 printk(" autoirq is %d", dev
->irq
);
229 } else if (dev
->irq
== 2)
231 * Fixup for users that don't know that IRQ 2 is really
232 * IRQ9, or don't know which one to set.
237 int irqval
= request_irq(dev
->irq
, &net_interrupt
, 0, cardname
, dev
);
239 printk("%s: unable to get IRQ %d (irqval=%d).\n",
240 dev
->name
, dev
->irq
, irqval
);
244 #endif /* jumpered interrupt */
247 * If we use a jumpered DMA channel, that should be probed for and
248 * allocated here as well. See lance.c for an example.
251 if (request_dma(dev
->dma
, cardname
)) {
252 printk("DMA %d allocation failed.\n", dev
->dma
);
255 printk(", assigned DMA %d.\n", dev
->dma
);
257 short dma_status
, new_dma_status
;
259 /* Read the DMA channel status registers. */
260 dma_status
= ((inb(DMA1_STAT_REG
) >> 4) & 0x0f) |
261 (inb(DMA2_STAT_REG
) & 0xf0);
262 /* Trigger a DMA request, perhaps pause a bit. */
263 outw(0x1234, ioaddr
+ 8);
264 /* Re-read the DMA status registers. */
265 new_dma_status
= ((inb(DMA1_STAT_REG
) >> 4) & 0x0f) |
266 (inb(DMA2_STAT_REG
) & 0xf0);
268 * Eliminate the old and floating requests,
269 * and DMA4 the cascade.
271 new_dma_status
^= dma_status
;
272 new_dma_status
&= ~0x10;
273 for (i
= 7; i
> 0; i
--)
274 if (test_bit(i
, &new_dma_status
)) {
279 printk("DMA probe failed.\n");
282 if (request_dma(dev
->dma
, cardname
)) {
283 printk("probed DMA %d allocation failed.\n", dev
->dma
);
287 #endif /* jumpered DMA */
289 /* Initialize the device structure. */
290 if (dev
->priv
== NULL
) {
291 dev
->priv
= kmalloc(sizeof(struct net_local
), GFP_KERNEL
);
292 if (dev
->priv
== NULL
)
296 memset(dev
->priv
, 0, sizeof(struct net_local
));
298 np
= (struct net_local
*)dev
->priv
;
299 spin_lock_init(&np
->lock
);
301 /* Grab the region so that no one else tries to probe our ioports. */
302 request_region(ioaddr
, NETCARD_IO_EXTENT
, cardname
);
304 dev
->open
= net_open
;
305 dev
->stop
= net_close
;
306 dev
->hard_start_xmit
= net_send_packet
;
307 dev
->get_stats
= net_get_stats
;
308 dev
->set_multicast_list
= &set_multicast_list
;
310 dev
->tx_timeout
= &net_tx_timeout
;
311 dev
->watchdog_timeo
= MY_TX_TIMEOUT
;
313 /* Fill in the fields of the device structure with ethernet values. */
319 static void net_tx_timeout(struct net_device
*dev
)
321 struct net_local
*np
= (struct net_local
*)dev
->priv
;
323 printk(KERN_WARNING
"%s: transmit timed out, %s?\n", dev
->name
,
324 tx_done(dev
) ? "IRQ conflict" : "network cable problem");
326 /* Try to restart the adaptor. */
327 chipset_init(dev
, 1);
329 np
->stats
.tx_errors
++;
331 /* If we have space available to accept new transmit
332 * requests, wake up the queueing layer. This would
333 * be the case if the chipset_init() call above just
334 * flushes out the tx queue and empties it.
336 * If instead, the tx queue is retained then the
337 * netif_wake_queue() call should be placed in the
338 * TX completion interrupt handler of the driver instead
342 netif_wake_queue(dev
);
346 * Open/initialize the board. This is called (in the current kernel)
347 * sometime after booting when the 'ifconfig' program is run.
349 * This routine should set everything up anew at each open, even
350 * registers that "should" only need to be set once at boot, so that
351 * there is non-reboot way to recover if something goes wrong.
354 net_open(struct net_device
*dev
)
356 struct net_local
*np
= (struct net_local
*)dev
->priv
;
357 int ioaddr
= dev
->base_addr
;
359 * This is used if the interrupt line can turned off (shared).
360 * See 3c503.c for an example of selecting the IRQ at config-time.
362 if (request_irq(dev
->irq
, &net_interrupt
, 0, cardname
, dev
)) {
366 * Always allocate the DMA channel after the IRQ,
367 * and clean up on failure.
369 if (request_dma(dev
->dma
, cardname
)) {
370 free_irq(dev
->irq
, dev
);
374 /* Reset the hardware here. Don't forget to set the station address. */
375 chipset_init(dev
, 1);
377 np
->open_time
= jiffies
;
379 /* We are now ready to accept transmit requeusts from
380 * the queueing layer of the networking.
382 netif_start_queue(dev
);
389 /* This will only be invoked if your driver is _not_ in XOFF state.
390 * What this means is that you need not check it, and that this
391 * invariant will hold if you make sure that the netif_*_queue()
392 * calls are done at the proper times.
394 static int net_send_packet(struct sk_buff
*skb
, struct net_device
*dev
)
396 struct net_local
*np
= (struct net_local
*)dev
->priv
;
397 int ioaddr
= dev
->base_addr
;
398 short length
= ETH_ZLEN
< skb
->len
? skb
->len
: ETH_ZLEN
;
399 unsigned char *buf
= skb
->data
;
401 /* If some error occurs while trying to transmit this
402 * packet, you should return '1' from this function.
403 * In such a case you _may not_ do anything to the
404 * SKB, it is still owned by the network queueing
405 * layer when an error is returned. This means you
406 * may not modify any SKB fields, you may not free
411 /* This is the most common case for modern hardware.
412 * The spinlock protects this code from the TX complete
413 * hardware interrupt handler. Queue flow control is
414 * thus managed under this lock as well.
416 spin_lock_irq(&np
->lock
);
418 add_to_tx_ring(np
, skb
, length
);
419 dev
->trans_start
= jiffies
;
421 /* If we just used up the very last entry in the
422 * TX ring on this device, tell the queueing
423 * layer to send no more.
426 netif_stop_queue(dev
);
428 /* When the TX completion hw interrupt arrives, this
429 * is when the transmit statistics are updated.
432 spin_unlock_irq(&np
->lock
);
434 /* This is the case for older hardware which takes
435 * a single transmit buffer at a time, and it is
436 * just written to the device via PIO.
438 * No spin locking is needed since there is no TX complete
439 * event. If by chance your card does have a TX complete
440 * hardware IRQ then you may need to utilize np->lock here.
442 hardware_send_packet(ioaddr
, buf
, length
);
443 np
->stats
.tx_bytes
+= skb
->len
;
445 dev
->trans_start
= jiffies
;
447 /* You might need to clean up and record Tx statistics here. */
448 if (inw(ioaddr
) == /*RU*/81)
449 np
->stats
.tx_aborted_errors
++;
457 /* This handles TX complete events posted by the device
460 void net_tx(struct net_device
*dev
)
462 struct net_local
*np
= (struct net_local
*)dev
->priv
;
465 /* This protects us from concurrent execution of
466 * our dev->hard_start_xmit function above.
468 spin_lock(&np
->lock
);
471 while (tx_entry_is_sent(np
, entry
)) {
472 struct sk_buff
*skb
= np
->skbs
[entry
];
474 np
->stats
.tx_bytes
+= skb
->len
;
475 dev_kfree_skb_irq (skb
);
477 entry
= next_tx_entry(np
, entry
);
481 /* If we had stopped the queue due to a "tx full"
482 * condition, and space has now been made available,
485 if (netif_queue_stopped(dev
) && ! tx_full(dev
))
486 netif_wake_queue(dev
);
488 spin_unlock(&np
->lock
);
493 * The typical workload of the driver:
494 * Handle the network interface interrupts.
496 static void net_interrupt(int irq
, void *dev_id
, struct pt_regs
* regs
)
498 struct net_device
*dev
= dev_id
;
499 struct net_local
*np
;
502 ioaddr
= dev
->base_addr
;
504 np
= (struct net_local
*)dev
->priv
;
505 status
= inw(ioaddr
+ 0);
507 if (status
& RX_INTR
) {
508 /* Got a packet(s). */
512 if (status
& TX_INTR
) {
513 /* Transmit complete. */
515 np
->stats
.tx_packets
++;
516 netif_wake_queue(dev
);
519 if (status
& COUNTERS_INTR
) {
520 /* Increment the appropriate 'localstats' field. */
521 np
->stats
.tx_window_errors
++;
525 /* We have a good packet(s), get it/them out of the buffers. */
527 net_rx(struct net_device
*dev
)
529 struct net_local
*lp
= (struct net_local
*)dev
->priv
;
530 int ioaddr
= dev
->base_addr
;
534 int status
= inw(ioaddr
);
535 int pkt_len
= inw(ioaddr
);
537 if (pkt_len
== 0) /* Read all the frames? */
538 break; /* Done for now */
540 if (status
& 0x40) { /* There was an error. */
541 lp
->stats
.rx_errors
++;
542 if (status
& 0x20) lp
->stats
.rx_frame_errors
++;
543 if (status
& 0x10) lp
->stats
.rx_over_errors
++;
544 if (status
& 0x08) lp
->stats
.rx_crc_errors
++;
545 if (status
& 0x04) lp
->stats
.rx_fifo_errors
++;
547 /* Malloc up new buffer. */
550 lp
->stats
.rx_bytes
+=pkt_len
;
552 skb
= dev_alloc_skb(pkt_len
);
554 printk(KERN_NOTICE
"%s: Memory squeeze, dropping packet.\n",
556 lp
->stats
.rx_dropped
++;
561 /* 'skb->data' points to the start of sk_buff data area. */
562 memcpy(skb_put(skb
,pkt_len
), (void*)dev
->rmem_start
,
565 insw(ioaddr
, skb
->data
, (pkt_len
+ 1) >> 1);
568 lp
->stats
.rx_packets
++;
570 } while (--boguscount
);
575 /* The inverse routine to net_open(). */
577 net_close(struct net_device
*dev
)
579 struct net_local
*lp
= (struct net_local
*)dev
->priv
;
580 int ioaddr
= dev
->base_addr
;
584 netif_stop_queue(dev
);
586 /* Flush the Tx and disable Rx here. */
588 disable_dma(dev
->dma
);
590 /* If not IRQ or DMA jumpered, free up the line. */
591 outw(0x00, ioaddr
+0); /* Release the physical interrupt line. */
593 free_irq(dev
->irq
, dev
);
596 /* Update the statistics here. */
605 * Get the current statistics.
606 * This may be called with the card open or closed.
608 static struct net_device_stats
*net_get_stats(struct net_device
*dev
)
610 struct net_local
*lp
= (struct net_local
*)dev
->priv
;
611 short ioaddr
= dev
->base_addr
;
614 /* Update the statistics from the device registers. */
615 lp
->stats
.rx_missed_errors
= inw(ioaddr
+1);
622 * Set or clear the multicast filter for this adaptor.
623 * num_addrs == -1 Promiscuous mode, receive all packets
624 * num_addrs == 0 Normal mode, clear multicast list
625 * num_addrs > 0 Multicast mode, receive normal and MC packets,
626 * and do best-effort filtering.
629 set_multicast_list(struct net_device
*dev
)
631 short ioaddr
= dev
->base_addr
;
632 if (dev
->flags
&IFF_PROMISC
)
634 /* Enable promiscuous mode */
635 outw(MULTICAST
|PROMISC
, ioaddr
);
637 else if((dev
->flags
&IFF_ALLMULTI
) || dev
->mc_count
> HW_MAX_ADDRS
)
639 /* Disable promiscuous mode, use normal mode. */
640 hardware_set_filter(NULL
);
642 outw(MULTICAST
, ioaddr
);
644 else if(dev
->mc_count
)
646 /* Walk the address list, and load the filter */
647 hardware_set_filter(dev
->mc_list
);
649 outw(MULTICAST
, ioaddr
);
657 static char devicename
[9] = { 0, };
658 static struct net_device this_device
= {
659 devicename
, /* will be inserted by linux/drivers/net/net_init.c */
661 0, 0, /* I/O address, IRQ */
662 0, 0, 0, NULL
, netcard_probe
};
664 static int io
= 0x300;
669 int init_module(void)
674 printk(KERN_WARNING
"%s: You shouldn't use auto-probing with insmod!\n",
677 /* Copy the parameters from insmod into the device structure. */
678 this_device
.base_addr
= io
;
679 this_device
.irq
= irq
;
680 this_device
.dma
= dma
;
681 this_device
.mem_start
= mem
;
683 if ((result
= register_netdev(&this_device
)) != 0)
692 /* No need to check MOD_IN_USE, as sys_delete_module() checks. */
693 unregister_netdev(&this_device
);
695 * If we don't do this, we can't re-insmod it later.
696 * Release irq/dma here, when you have jumpered versions and
697 * allocate them in net_probe1().
700 free_irq(this_device.irq, dev);
701 free_dma(this_device.dma);
703 release_region(this_device
.base_addr
, NETCARD_IO_EXTENT
);
705 if (this_device
.priv
)
706 kfree(this_device
.priv
);
714 * gcc -D__KERNEL__ -Wall -Wstrict-prototypes -Wwrite-strings
715 * -Wredundant-decls -O2 -m486 -c skeleton.c
717 * kept-new-versions: 5