1/*
  2 * Simulated Ethernet Driver
  3 *
  4 * Copyright (C) 1999-2001, 2003 Hewlett-Packard Co
  5 *	Stephane Eranian <eranian@hpl.hp.com>
  6 */
  7#include <linux/kernel.h>
  8#include <linux/sched.h>
  9#include <linux/types.h>
 10#include <linux/in.h>
 11#include <linux/string.h>
 12#include <linux/init.h>
 13#include <linux/errno.h>
 14#include <linux/interrupt.h>
 15#include <linux/netdevice.h>
 16#include <linux/etherdevice.h>
 17#include <linux/inetdevice.h>
 18#include <linux/if_ether.h>
 19#include <linux/if_arp.h>
 20#include <linux/skbuff.h>
 21#include <linux/notifier.h>
 22#include <linux/bitops.h>
 23#include <asm/system.h>
 24#include <asm/irq.h>
 25#include <asm/hpsim.h>
 26
 27#include "hpsim_ssc.h"
 28
 29#define SIMETH_RECV_MAX	10
 30
 31/*
 32 * Maximum possible received frame for Ethernet.
 33 * We preallocate an sk_buff of that size to avoid costly
 34 * memcpy for temporary buffer into sk_buff. We do basically
 35 * what's done in other drivers, like eepro with a ring.
 36 * The difference is, of course, that we don't have real DMA !!!
 37 */
 38#define SIMETH_FRAME_SIZE	ETH_FRAME_LEN
 39
 40
 41#define NETWORK_INTR			8
 42
 43struct simeth_local {
 44	struct net_device_stats stats;
 45	int 			simfd;	 /* descriptor in the simulator */
 46};
 47
 48static int simeth_probe1(void);
 49static int simeth_open(struct net_device *dev);
 50static int simeth_close(struct net_device *dev);
 51static int simeth_tx(struct sk_buff *skb, struct net_device *dev);
 52static int simeth_rx(struct net_device *dev);
 53static struct net_device_stats *simeth_get_stats(struct net_device *dev);
 54static irqreturn_t simeth_interrupt(int irq, void *dev_id);
 55static void set_multicast_list(struct net_device *dev);
 56static int simeth_device_event(struct notifier_block *this,unsigned long event, void *ptr);
 57
 58static char *simeth_version="0.3";
 59
 60/*
 61 * This variable is used to establish a mapping between the Linux/ia64 kernel
 62 * and the host linux kernel.
 63 *
 64 * As of today, we support only one card, even though most of the code
 65 * is ready for many more. The mapping is then:
 66 *	linux/ia64 -> linux/x86
 67 * 	   eth0    -> eth1
 68 *
 69 * In the future, we some string operations, we could easily support up
 70 * to 10 cards (0-9).
 71 *
 72 * The default mapping can be changed on the kernel command line by
 73 * specifying simeth=ethX (or whatever string you want).
 74 */
 75static char *simeth_device="eth0";	 /* default host interface to use */
 76
 77
 78
 79static volatile unsigned int card_count; /* how many cards "found" so far */
 80static int simeth_debug;		/* set to 1 to get debug information */
 81
 82/*
 83 * Used to catch IFF_UP & IFF_DOWN events
 84 */
 85static struct notifier_block simeth_dev_notifier = {
 86	simeth_device_event,
 87	NULL
 88};
 89
 90
 91/*
 92 * Function used when using a kernel command line option.
 93 *
 94 * Format: simeth=interface_name (like eth0)
 95 */
 96static int __init
 97simeth_setup(char *str)
 98{
 99	simeth_device = str;
100	return 1;
101}
102
103__setup("simeth=", simeth_setup);
104
105/*
106 * Function used to probe for simeth devices when not installed
107 * as a loadable module
108 */
109
110int __init
111simeth_probe (void)
112{
113	int r;
114
115	printk(KERN_INFO "simeth: v%s\n", simeth_version);
116
117	r = simeth_probe1();
118
119	if (r == 0) register_netdevice_notifier(&simeth_dev_notifier);
120
121	return r;
122}
123
124static inline int
125netdev_probe(char *name, unsigned char *ether)
126{
127	return ia64_ssc(__pa(name), __pa(ether), 0,0, SSC_NETDEV_PROBE);
128}
129
130
131static inline int
132netdev_connect(int irq)
133{
134	/* XXX Fix me
135	 * this does not support multiple cards
136	 * also no return value
137	 */
138	ia64_ssc_connect_irq(NETWORK_INTR, irq);
139	return 0;
140}
141
142static inline int
143netdev_attach(int fd, int irq, unsigned int ipaddr)
144{
145	/* this puts the host interface in the right mode (start interrupting) */
146	return ia64_ssc(fd, ipaddr, 0,0, SSC_NETDEV_ATTACH);
147}
148
149
150static inline int
151netdev_detach(int fd)
152{
153	/*
154	 * inactivate the host interface (don't interrupt anymore) */
155	return ia64_ssc(fd, 0,0,0, SSC_NETDEV_DETACH);
156}
157
158static inline int
159netdev_send(int fd, unsigned char *buf, unsigned int len)
160{
161	return ia64_ssc(fd, __pa(buf), len, 0, SSC_NETDEV_SEND);
162}
163
164static inline int
165netdev_read(int fd, unsigned char *buf, unsigned int len)
166{
167	return ia64_ssc(fd, __pa(buf), len, 0, SSC_NETDEV_RECV);
168}
169
170static const struct net_device_ops simeth_netdev_ops = {
171	.ndo_open		= simeth_open,
172	.ndo_stop		= simeth_close,
173	.ndo_start_xmit		= simeth_tx,
174	.ndo_get_stats		= simeth_get_stats,
175	.ndo_set_multicast_list	= set_multicast_list, /* not yet used */
176
177};
178
179/*
180 * Function shared with module code, so cannot be in init section
181 *
182 * So far this function "detects" only one card (test_&_set) but could
183 * be extended easily.
184 *
185 * Return:
186 * 	- -ENODEV is no device found
187 *	- -ENOMEM is no more memory
188 *	- 0 otherwise
189 */
190static int
191simeth_probe1(void)
192{
193	unsigned char mac_addr[ETH_ALEN];
194	struct simeth_local *local;
195	struct net_device *dev;
196	int fd, i, err, rc;
197
198	/*
199	 * XXX Fix me
200	 * let's support just one card for now
201	 */
202	if (test_and_set_bit(0, &card_count))
203		return -ENODEV;
204
205	/*
206	 * check with the simulator for the device
207	 */
208	fd = netdev_probe(simeth_device, mac_addr);
209	if (fd == -1)
210		return -ENODEV;
211
212	dev = alloc_etherdev(sizeof(struct simeth_local));
213	if (!dev)
214		return -ENOMEM;
215
216	memcpy(dev->dev_addr, mac_addr, sizeof(mac_addr));
217
218	local = netdev_priv(dev);
219	local->simfd = fd; /* keep track of underlying file descriptor */
220
221	dev->netdev_ops = &simeth_netdev_ops;
222
223	err = register_netdev(dev);
224	if (err) {
225		free_netdev(dev);
226		return err;
227	}
228
229	if ((rc = assign_irq_vector(AUTO_ASSIGN)) < 0)
230		panic("%s: out of interrupt vectors!\n", __func__);
231	dev->irq = rc;
232
233	/*
234	 * attach the interrupt in the simulator, this does enable interrupts
235	 * until a netdev_attach() is called
236	 */
237	netdev_connect(dev->irq);
238
239	printk(KERN_INFO "%s: hosteth=%s simfd=%d, HwAddr",
240	       dev->name, simeth_device, local->simfd);
241	for(i = 0; i < ETH_ALEN; i++) {
242		printk(" %2.2x", dev->dev_addr[i]);
243	}
244	printk(", IRQ %d\n", dev->irq);
245
246	return 0;
247}
248
249/*
250 * actually binds the device to an interrupt vector
251 */
252static int
253simeth_open(struct net_device *dev)
254{
255	if (request_irq(dev->irq, simeth_interrupt, 0, "simeth", dev)) {
256		printk(KERN_WARNING "simeth: unable to get IRQ %d.\n", dev->irq);
257		return -EAGAIN;
258	}
259
260	netif_start_queue(dev);
261
262	return 0;
263}
264
265/* copied from lapbether.c */
266static __inline__ int dev_is_ethdev(struct net_device *dev)
267{
268       return ( dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5));
269}
270
271
272/*
273 * Handler for IFF_UP or IFF_DOWN
274 *
275 * The reason for that is that we don't want to be interrupted when the
276 * interface is down. There is no way to unconnect in the simualtor. Instead
277 * we use this function to shutdown packet processing in the frame filter
278 * in the simulator. Thus no interrupts are generated
279 *
280 *
281 * That's also the place where we pass the IP address of this device to the
282 * simulator so that that we can start filtering packets for it
283 *
284 * There may be a better way of doing this, but I don't know which yet.
285 */
286static int
287simeth_device_event(struct notifier_block *this,unsigned long event, void *ptr)
288{
289	struct net_device *dev = ptr;
290	struct simeth_local *local;
291	struct in_device *in_dev;
292	struct in_ifaddr **ifap = NULL;
293	struct in_ifaddr *ifa = NULL;
294	int r;
295
296
297	if ( ! dev ) {
298		printk(KERN_WARNING "simeth_device_event dev=0\n");
299		return NOTIFY_DONE;
300	}
301
302	if (dev_net(dev) != &init_net)
303		return NOTIFY_DONE;
304
305	if ( event != NETDEV_UP && event != NETDEV_DOWN ) return NOTIFY_DONE;
306
307	/*
308	 * Check whether or not it's for an ethernet device
309	 *
310	 * XXX Fixme: This works only as long as we support one
311	 * type of ethernet device.
312	 */
313	if ( !dev_is_ethdev(dev) ) return NOTIFY_DONE;
314
315	if ((in_dev=dev->ip_ptr) != NULL) {
316		for (ifap=&in_dev->ifa_list; (ifa=*ifap) != NULL; ifap=&ifa->ifa_next)
317			if (strcmp(dev->name, ifa->ifa_label) == 0) break;
318	}
319	if ( ifa == NULL ) {
320		printk(KERN_ERR "simeth_open: can't find device %s's ifa\n", dev->name);
321		return NOTIFY_DONE;
322	}
323
324	printk(KERN_INFO "simeth_device_event: %s ipaddr=0x%x\n",
325	       dev->name, ntohl(ifa->ifa_local));
326
327	/*
328	 * XXX Fix me
329	 * if the device was up, and we're simply reconfiguring it, not sure
330	 * we get DOWN then UP.
331	 */
332
333	local = netdev_priv(dev);
334	/* now do it for real */
335	r = event == NETDEV_UP ?
336		netdev_attach(local->simfd, dev->irq, ntohl(ifa->ifa_local)):
337		netdev_detach(local->simfd);
338
339	printk(KERN_INFO "simeth: netdev_attach/detach: event=%s ->%d\n",
340	       event == NETDEV_UP ? "attach":"detach", r);
341
342	return NOTIFY_DONE;
343}
344
345static int
346simeth_close(struct net_device *dev)
347{
348	netif_stop_queue(dev);
349
350	free_irq(dev->irq, dev);
351
352	return 0;
353}
354
355/*
356 * Only used for debug
357 */
358static void
359frame_print(unsigned char *from, unsigned char *frame, int len)
360{
361	int i;
362
363	printk("%s: (%d) %02x", from, len, frame[0] & 0xff);
364	for(i=1; i < 6; i++ ) {
365		printk(":%02x", frame[i] &0xff);
366	}
367	printk(" %2x", frame[6] &0xff);
368	for(i=7; i < 12; i++ ) {
369		printk(":%02x", frame[i] &0xff);
370	}
371	printk(" [%02x%02x]\n", frame[12], frame[13]);
372
373	for(i=14; i < len; i++ ) {
374		printk("%02x ", frame[i] &0xff);
375		if ( (i%10)==0) printk("\n");
376	}
377	printk("\n");
378}
379
380
381/*
382 * Function used to transmit of frame, very last one on the path before
383 * going to the simulator.
384 */
385static int
386simeth_tx(struct sk_buff *skb, struct net_device *dev)
387{
388	struct simeth_local *local = netdev_priv(dev);
389
390#if 0
391	/* ensure we have at least ETH_ZLEN bytes (min frame size) */
392	unsigned int length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
393	/* Where do the extra padding bytes comes from inthe skbuff ? */
394#else
395	/* the real driver in the host system is going to take care of that
396	 * or maybe it's the NIC itself.
397	 */
398	unsigned int length = skb->len;
399#endif
400
401	local->stats.tx_bytes += skb->len;
402	local->stats.tx_packets++;
403
404
405	if (simeth_debug > 5) frame_print("simeth_tx", skb->data, length);
406
407	netdev_send(local->simfd, skb->data, length);
408
409	/*
410	 * we are synchronous on write, so we don't simulate a
411	 * trasnmit complete interrupt, thus we don't need to arm a tx
412	 */
413
414	dev_kfree_skb(skb);
415	return NETDEV_TX_OK;
416}
417
418static inline struct sk_buff *
419make_new_skb(struct net_device *dev)
420{
421	struct sk_buff *nskb;
422
423	/*
424	 * The +2 is used to make sure that the IP header is nicely
425	 * aligned (on 4byte boundary I assume 14+2=16)
426	 */
427	nskb = dev_alloc_skb(SIMETH_FRAME_SIZE + 2);
428	if ( nskb == NULL ) {
429		printk(KERN_NOTICE "%s: memory squeeze. dropping packet.\n", dev->name);
430		return NULL;
431	}
432
433	skb_reserve(nskb, 2);	/* Align IP on 16 byte boundaries */
434
435	skb_put(nskb,SIMETH_FRAME_SIZE);
436
437	return nskb;
438}
439
440/*
441 * called from interrupt handler to process a received frame
442 */
443static int
444simeth_rx(struct net_device *dev)
445{
446	struct simeth_local	*local;
447	struct sk_buff		*skb;
448	int			len;
449	int			rcv_count = SIMETH_RECV_MAX;
450
451	local = netdev_priv(dev);
452	/*
453	 * the loop concept has been borrowed from other drivers
454	 * looks to me like it's a throttling thing to avoid pushing to many
455	 * packets at one time into the stack. Making sure we can process them
456	 * upstream and make forward progress overall
457	 */
458	do {
459		if ( (skb=make_new_skb(dev)) == NULL ) {
460			printk(KERN_NOTICE "%s: memory squeeze. dropping packet.\n", dev->name);
461			local->stats.rx_dropped++;
462			return 0;
463		}
464		/*
465		 * Read only one frame at a time
466		 */
467		len = netdev_read(local->simfd, skb->data, SIMETH_FRAME_SIZE);
468		if ( len == 0 ) {
469			if ( simeth_debug > 0 ) printk(KERN_WARNING "%s: count=%d netdev_read=0\n",
470						       dev->name, SIMETH_RECV_MAX-rcv_count);
471			break;
472		}
473#if 0
474		/*
475		 * XXX Fix me
476		 * Should really do a csum+copy here
477		 */
478		skb_copy_to_linear_data(skb, frame, len);
479#endif
480		skb->protocol = eth_type_trans(skb, dev);
481
482		if ( simeth_debug > 6 ) frame_print("simeth_rx", skb->data, len);
483
484		/*
485		 * push the packet up & trigger software interrupt
486		 */
487		netif_rx(skb);
488
489		local->stats.rx_packets++;
490		local->stats.rx_bytes += len;
491
492	} while ( --rcv_count );
493
494	return len; /* 0 = nothing left to read, otherwise, we can try again */
495}
496
497/*
498 * Interrupt handler (Yes, we can do it too !!!)
499 */
500static irqreturn_t
501simeth_interrupt(int irq, void *dev_id)
502{
503	struct net_device *dev = dev_id;
504
505	/*
506	 * very simple loop because we get interrupts only when receiving
507	 */
508	while (simeth_rx(dev));
509	return IRQ_HANDLED;
510}
511
512static struct net_device_stats *
513simeth_get_stats(struct net_device *dev)
514{
515	struct simeth_local *local = netdev_priv(dev);
516
517	return &local->stats;
518}
519
520/* fake multicast ability */
521static void
522set_multicast_list(struct net_device *dev)
523{
524	printk(KERN_WARNING "%s: set_multicast_list called\n", dev->name);
525}
526
527__initcall(simeth_probe);