1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *
4  * arch/xtensa/platforms/iss/network.c
5  *
6  * Platform specific initialization.
7  *
8  * Authors: Chris Zankel <chris@zankel.net>
9  * Based on work form the UML team.
10  *
11  * Copyright 2005 Tensilica Inc.
12  */
13 
14 #define pr_fmt(fmt) "%s: " fmt, __func__
15 
16 #include <linux/list.h>
17 #include <linux/irq.h>
18 #include <linux/spinlock.h>
19 #include <linux/slab.h>
20 #include <linux/timer.h>
21 #include <linux/if_ether.h>
22 #include <linux/inetdevice.h>
23 #include <linux/init.h>
24 #include <linux/if_tun.h>
25 #include <linux/etherdevice.h>
26 #include <linux/interrupt.h>
27 #include <linux/ioctl.h>
28 #include <linux/memblock.h>
29 #include <linux/ethtool.h>
30 #include <linux/rtnetlink.h>
31 #include <linux/platform_device.h>
32 
33 #include <platform/simcall.h>
34 
35 #define DRIVER_NAME "iss-netdev"
36 #define ETH_MAX_PACKET 1500
37 #define ETH_HEADER_OTHER 14
38 #define ISS_NET_TIMER_VALUE (HZ / 10)
39 
40 
41 static DEFINE_SPINLOCK(opened_lock);
42 static LIST_HEAD(opened);
43 
44 static DEFINE_SPINLOCK(devices_lock);
45 static LIST_HEAD(devices);
46 
47 /* ------------------------------------------------------------------------- */
48 
49 /* We currently only support the TUNTAP transport protocol. */
50 
51 #define TRANSPORT_TUNTAP_NAME "tuntap"
52 #define TRANSPORT_TUNTAP_MTU ETH_MAX_PACKET
53 
54 struct tuntap_info {
55 	char dev_name[IFNAMSIZ];
56 	int fd;
57 };
58 
59 /* ------------------------------------------------------------------------- */
60 
61 
62 /* This structure contains out private information for the driver. */
63 
64 struct iss_net_private {
65 	struct list_head device_list;
66 	struct list_head opened_list;
67 
68 	spinlock_t lock;
69 	struct net_device *dev;
70 	struct platform_device pdev;
71 	struct timer_list tl;
72 	struct net_device_stats stats;
73 
74 	struct timer_list timer;
75 	unsigned int timer_val;
76 
77 	int index;
78 	int mtu;
79 
80 	struct {
81 		union {
82 			struct tuntap_info tuntap;
83 		} info;
84 
85 		int (*open)(struct iss_net_private *lp);
86 		void (*close)(struct iss_net_private *lp);
87 		int (*read)(struct iss_net_private *lp, struct sk_buff **skb);
88 		int (*write)(struct iss_net_private *lp, struct sk_buff **skb);
89 		unsigned short (*protocol)(struct sk_buff *skb);
90 		int (*poll)(struct iss_net_private *lp);
91 	} tp;
92 
93 };
94 
95 /* ================================ HELPERS ================================ */
96 
97 
98 static char *split_if_spec(char *str, ...)
99 {
100 	char **arg, *end;
101 	va_list ap;
102 
103 	va_start(ap, str);
104 	while ((arg = va_arg(ap, char**)) != NULL) {
105 		if (*str == '\0') {
106 			va_end(ap);
107 			return NULL;
108 		}
109 		end = strchr(str, ',');
110 		if (end != str)
111 			*arg = str;
112 		if (end == NULL) {
113 			va_end(ap);
114 			return NULL;
115 		}
116 		*end++ = '\0';
117 		str = end;
118 	}
119 	va_end(ap);
120 	return str;
121 }
122 
123 /* Set Ethernet address of the specified device. */
124 
125 static void setup_etheraddr(struct net_device *dev, char *str)
126 {
127 	u8 addr[ETH_ALEN];
128 
129 	if (str == NULL)
130 		goto random;
131 
132 	if (!mac_pton(str, addr)) {
133 		pr_err("%s: failed to parse '%s' as an ethernet address\n",
134 		       dev->name, str);
135 		goto random;
136 	}
137 	if (is_multicast_ether_addr(addr)) {
138 		pr_err("%s: attempt to assign a multicast ethernet address\n",
139 		       dev->name);
140 		goto random;
141 	}
142 	if (!is_valid_ether_addr(addr)) {
143 		pr_err("%s: attempt to assign an invalid ethernet address\n",
144 		       dev->name);
145 		goto random;
146 	}
147 	if (!is_local_ether_addr(addr))
148 		pr_warn("%s: assigning a globally valid ethernet address\n",
149 			dev->name);
150 	eth_hw_addr_set(dev, addr);
151 	return;
152 
153 random:
154 	pr_info("%s: choosing a random ethernet address\n",
155 		dev->name);
156 	eth_hw_addr_random(dev);
157 }
158 
159 /* ======================= TUNTAP TRANSPORT INTERFACE ====================== */
160 
161 static int tuntap_open(struct iss_net_private *lp)
162 {
163 	struct ifreq ifr;
164 	char *dev_name = lp->tp.info.tuntap.dev_name;
165 	int err = -EINVAL;
166 	int fd;
167 
168 	fd = simc_open("/dev/net/tun", 02, 0); /* O_RDWR */
169 	if (fd < 0) {
170 		pr_err("%s: failed to open /dev/net/tun, returned %d (errno = %d)\n",
171 		       lp->dev->name, fd, errno);
172 		return fd;
173 	}
174 
175 	memset(&ifr, 0, sizeof(ifr));
176 	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
177 	strscpy(ifr.ifr_name, dev_name, sizeof(ifr.ifr_name));
178 
179 	err = simc_ioctl(fd, TUNSETIFF, &ifr);
180 	if (err < 0) {
181 		pr_err("%s: failed to set interface %s, returned %d (errno = %d)\n",
182 		       lp->dev->name, dev_name, err, errno);
183 		simc_close(fd);
184 		return err;
185 	}
186 
187 	lp->tp.info.tuntap.fd = fd;
188 	return err;
189 }
190 
191 static void tuntap_close(struct iss_net_private *lp)
192 {
193 	simc_close(lp->tp.info.tuntap.fd);
194 	lp->tp.info.tuntap.fd = -1;
195 }
196 
197 static int tuntap_read(struct iss_net_private *lp, struct sk_buff **skb)
198 {
199 	return simc_read(lp->tp.info.tuntap.fd,
200 			(*skb)->data, (*skb)->dev->mtu + ETH_HEADER_OTHER);
201 }
202 
203 static int tuntap_write(struct iss_net_private *lp, struct sk_buff **skb)
204 {
205 	return simc_write(lp->tp.info.tuntap.fd, (*skb)->data, (*skb)->len);
206 }
207 
208 unsigned short tuntap_protocol(struct sk_buff *skb)
209 {
210 	return eth_type_trans(skb, skb->dev);
211 }
212 
213 static int tuntap_poll(struct iss_net_private *lp)
214 {
215 	return simc_poll(lp->tp.info.tuntap.fd);
216 }
217 
218 /*
219  * ethX=tuntap,[mac address],device name
220  */
221 
222 static int tuntap_probe(struct iss_net_private *lp, int index, char *init)
223 {
224 	struct net_device *dev = lp->dev;
225 	char *dev_name = NULL, *mac_str = NULL, *rem = NULL;
226 
227 	/* Transport should be 'tuntap': ethX=tuntap,mac,dev_name */
228 
229 	if (strncmp(init, TRANSPORT_TUNTAP_NAME,
230 		    sizeof(TRANSPORT_TUNTAP_NAME) - 1))
231 		return 0;
232 
233 	init += sizeof(TRANSPORT_TUNTAP_NAME) - 1;
234 	if (*init == ',') {
235 		rem = split_if_spec(init + 1, &mac_str, &dev_name);
236 		if (rem != NULL) {
237 			pr_err("%s: extra garbage on specification : '%s'\n",
238 			       dev->name, rem);
239 			return 0;
240 		}
241 	} else if (*init != '\0') {
242 		pr_err("%s: invalid argument: %s. Skipping device!\n",
243 		       dev->name, init);
244 		return 0;
245 	}
246 
247 	if (!dev_name) {
248 		pr_err("%s: missing tuntap device name\n", dev->name);
249 		return 0;
250 	}
251 
252 	strscpy(lp->tp.info.tuntap.dev_name, dev_name,
253 		sizeof(lp->tp.info.tuntap.dev_name));
254 
255 	setup_etheraddr(dev, mac_str);
256 
257 	lp->mtu = TRANSPORT_TUNTAP_MTU;
258 
259 	lp->tp.info.tuntap.fd = -1;
260 
261 	lp->tp.open = tuntap_open;
262 	lp->tp.close = tuntap_close;
263 	lp->tp.read = tuntap_read;
264 	lp->tp.write = tuntap_write;
265 	lp->tp.protocol = tuntap_protocol;
266 	lp->tp.poll = tuntap_poll;
267 
268 	return 1;
269 }
270 
271 /* ================================ ISS NET ================================ */
272 
273 static int iss_net_rx(struct net_device *dev)
274 {
275 	struct iss_net_private *lp = netdev_priv(dev);
276 	int pkt_len;
277 	struct sk_buff *skb;
278 
279 	/* Check if there is any new data. */
280 
281 	if (lp->tp.poll(lp) == 0)
282 		return 0;
283 
284 	/* Try to allocate memory, if it fails, try again next round. */
285 
286 	skb = dev_alloc_skb(dev->mtu + 2 + ETH_HEADER_OTHER);
287 	if (skb == NULL) {
288 		lp->stats.rx_dropped++;
289 		return 0;
290 	}
291 
292 	skb_reserve(skb, 2);
293 
294 	/* Setup skb */
295 
296 	skb->dev = dev;
297 	skb_reset_mac_header(skb);
298 	pkt_len = lp->tp.read(lp, &skb);
299 	skb_put(skb, pkt_len);
300 
301 	if (pkt_len > 0) {
302 		skb_trim(skb, pkt_len);
303 		skb->protocol = lp->tp.protocol(skb);
304 
305 		lp->stats.rx_bytes += skb->len;
306 		lp->stats.rx_packets++;
307 		netif_rx(skb);
308 		return pkt_len;
309 	}
310 	kfree_skb(skb);
311 	return pkt_len;
312 }
313 
314 static int iss_net_poll(void)
315 {
316 	struct list_head *ele;
317 	int err, ret = 0;
318 
319 	spin_lock(&opened_lock);
320 
321 	list_for_each(ele, &opened) {
322 		struct iss_net_private *lp;
323 
324 		lp = list_entry(ele, struct iss_net_private, opened_list);
325 
326 		if (!netif_running(lp->dev))
327 			break;
328 
329 		spin_lock(&lp->lock);
330 
331 		while ((err = iss_net_rx(lp->dev)) > 0)
332 			ret++;
333 
334 		spin_unlock(&lp->lock);
335 
336 		if (err < 0) {
337 			pr_err("Device '%s' read returned %d, shutting it down\n",
338 			       lp->dev->name, err);
339 			dev_close(lp->dev);
340 		} else {
341 			/* FIXME reactivate_fd(lp->fd, ISS_ETH_IRQ); */
342 		}
343 	}
344 
345 	spin_unlock(&opened_lock);
346 	return ret;
347 }
348 
349 
350 static void iss_net_timer(struct timer_list *t)
351 {
352 	struct iss_net_private *lp = from_timer(lp, t, timer);
353 
354 	iss_net_poll();
355 	spin_lock(&lp->lock);
356 	mod_timer(&lp->timer, jiffies + lp->timer_val);
357 	spin_unlock(&lp->lock);
358 }
359 
360 
361 static int iss_net_open(struct net_device *dev)
362 {
363 	struct iss_net_private *lp = netdev_priv(dev);
364 	int err;
365 
366 	spin_lock_bh(&lp->lock);
367 
368 	err = lp->tp.open(lp);
369 	if (err < 0)
370 		goto out;
371 
372 	netif_start_queue(dev);
373 
374 	/* clear buffer - it can happen that the host side of the interface
375 	 * is full when we get here. In this case, new data is never queued,
376 	 * SIGIOs never arrive, and the net never works.
377 	 */
378 	while ((err = iss_net_rx(dev)) > 0)
379 		;
380 
381 	spin_unlock_bh(&lp->lock);
382 	spin_lock_bh(&opened_lock);
383 	list_add(&lp->opened_list, &opened);
384 	spin_unlock_bh(&opened_lock);
385 	spin_lock_bh(&lp->lock);
386 
387 	timer_setup(&lp->timer, iss_net_timer, 0);
388 	lp->timer_val = ISS_NET_TIMER_VALUE;
389 	mod_timer(&lp->timer, jiffies + lp->timer_val);
390 
391 out:
392 	spin_unlock_bh(&lp->lock);
393 	return err;
394 }
395 
396 static int iss_net_close(struct net_device *dev)
397 {
398 	struct iss_net_private *lp = netdev_priv(dev);
399 	netif_stop_queue(dev);
400 	spin_lock_bh(&lp->lock);
401 
402 	spin_lock(&opened_lock);
403 	list_del(&opened);
404 	spin_unlock(&opened_lock);
405 
406 	del_timer_sync(&lp->timer);
407 
408 	lp->tp.close(lp);
409 
410 	spin_unlock_bh(&lp->lock);
411 	return 0;
412 }
413 
414 static int iss_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
415 {
416 	struct iss_net_private *lp = netdev_priv(dev);
417 	int len;
418 
419 	netif_stop_queue(dev);
420 	spin_lock_bh(&lp->lock);
421 
422 	len = lp->tp.write(lp, &skb);
423 
424 	if (len == skb->len) {
425 		lp->stats.tx_packets++;
426 		lp->stats.tx_bytes += skb->len;
427 		netif_trans_update(dev);
428 		netif_start_queue(dev);
429 
430 		/* this is normally done in the interrupt when tx finishes */
431 		netif_wake_queue(dev);
432 
433 	} else if (len == 0) {
434 		netif_start_queue(dev);
435 		lp->stats.tx_dropped++;
436 
437 	} else {
438 		netif_start_queue(dev);
439 		pr_err("%s: %s failed(%d)\n", dev->name, __func__, len);
440 	}
441 
442 	spin_unlock_bh(&lp->lock);
443 
444 	dev_kfree_skb(skb);
445 	return NETDEV_TX_OK;
446 }
447 
448 
449 static struct net_device_stats *iss_net_get_stats(struct net_device *dev)
450 {
451 	struct iss_net_private *lp = netdev_priv(dev);
452 	return &lp->stats;
453 }
454 
455 static void iss_net_set_multicast_list(struct net_device *dev)
456 {
457 }
458 
459 static void iss_net_tx_timeout(struct net_device *dev, unsigned int txqueue)
460 {
461 }
462 
463 static int iss_net_set_mac(struct net_device *dev, void *addr)
464 {
465 	struct iss_net_private *lp = netdev_priv(dev);
466 	struct sockaddr *hwaddr = addr;
467 
468 	if (!is_valid_ether_addr(hwaddr->sa_data))
469 		return -EADDRNOTAVAIL;
470 	spin_lock_bh(&lp->lock);
471 	eth_hw_addr_set(dev, hwaddr->sa_data);
472 	spin_unlock_bh(&lp->lock);
473 	return 0;
474 }
475 
476 static int iss_net_change_mtu(struct net_device *dev, int new_mtu)
477 {
478 	return -EINVAL;
479 }
480 
481 void iss_net_user_timer_expire(struct timer_list *unused)
482 {
483 }
484 
485 
486 static struct platform_driver iss_net_driver = {
487 	.driver = {
488 		.name  = DRIVER_NAME,
489 	},
490 };
491 
492 static int driver_registered;
493 
494 static const struct net_device_ops iss_netdev_ops = {
495 	.ndo_open		= iss_net_open,
496 	.ndo_stop		= iss_net_close,
497 	.ndo_get_stats		= iss_net_get_stats,
498 	.ndo_start_xmit		= iss_net_start_xmit,
499 	.ndo_validate_addr	= eth_validate_addr,
500 	.ndo_change_mtu		= iss_net_change_mtu,
501 	.ndo_set_mac_address	= iss_net_set_mac,
502 	.ndo_tx_timeout		= iss_net_tx_timeout,
503 	.ndo_set_rx_mode	= iss_net_set_multicast_list,
504 };
505 
506 static int iss_net_configure(int index, char *init)
507 {
508 	struct net_device *dev;
509 	struct iss_net_private *lp;
510 	int err;
511 
512 	dev = alloc_etherdev(sizeof(*lp));
513 	if (dev == NULL) {
514 		pr_err("eth_configure: failed to allocate device\n");
515 		return 1;
516 	}
517 
518 	/* Initialize private element. */
519 
520 	lp = netdev_priv(dev);
521 	*lp = (struct iss_net_private) {
522 		.device_list		= LIST_HEAD_INIT(lp->device_list),
523 		.opened_list		= LIST_HEAD_INIT(lp->opened_list),
524 		.dev			= dev,
525 		.index			= index,
526 	};
527 
528 	spin_lock_init(&lp->lock);
529 	/*
530 	 * If this name ends up conflicting with an existing registered
531 	 * netdevice, that is OK, register_netdev{,ice}() will notice this
532 	 * and fail.
533 	 */
534 	snprintf(dev->name, sizeof(dev->name), "eth%d", index);
535 
536 	/*
537 	 * Try all transport protocols.
538 	 * Note: more protocols can be added by adding '&& !X_init(lp, eth)'.
539 	 */
540 
541 	if (!tuntap_probe(lp, index, init)) {
542 		pr_err("%s: invalid arguments. Skipping device!\n",
543 		       dev->name);
544 		goto errout;
545 	}
546 
547 	pr_info("Netdevice %d (%pM)\n", index, dev->dev_addr);
548 
549 	/* sysfs register */
550 
551 	if (!driver_registered) {
552 		platform_driver_register(&iss_net_driver);
553 		driver_registered = 1;
554 	}
555 
556 	spin_lock(&devices_lock);
557 	list_add(&lp->device_list, &devices);
558 	spin_unlock(&devices_lock);
559 
560 	lp->pdev.id = index;
561 	lp->pdev.name = DRIVER_NAME;
562 	platform_device_register(&lp->pdev);
563 	SET_NETDEV_DEV(dev, &lp->pdev.dev);
564 
565 	dev->netdev_ops = &iss_netdev_ops;
566 	dev->mtu = lp->mtu;
567 	dev->watchdog_timeo = (HZ >> 1);
568 	dev->irq = -1;
569 
570 	rtnl_lock();
571 	err = register_netdevice(dev);
572 	rtnl_unlock();
573 
574 	if (err) {
575 		pr_err("%s: error registering net device!\n", dev->name);
576 		/* XXX: should we call ->remove() here? */
577 		free_netdev(dev);
578 		return 1;
579 	}
580 
581 	timer_setup(&lp->tl, iss_net_user_timer_expire, 0);
582 
583 	return 0;
584 
585 errout:
586 	/* FIXME: unregister; free, etc.. */
587 	return -EIO;
588 }
589 
590 /* ------------------------------------------------------------------------- */
591 
592 /* Filled in during early boot */
593 
594 struct list_head eth_cmd_line = LIST_HEAD_INIT(eth_cmd_line);
595 
596 struct iss_net_init {
597 	struct list_head list;
598 	char *init;		/* init string */
599 	int index;
600 };
601 
602 /*
603  * Parse the command line and look for 'ethX=...' fields, and register all
604  * those fields. They will be later initialized in iss_net_init.
605  */
606 
607 static int __init iss_net_setup(char *str)
608 {
609 	struct iss_net_private *device = NULL;
610 	struct iss_net_init *new;
611 	struct list_head *ele;
612 	char *end;
613 	int rc;
614 	unsigned n;
615 
616 	end = strchr(str, '=');
617 	if (!end) {
618 		pr_err("Expected '=' after device number\n");
619 		return 1;
620 	}
621 	*end = 0;
622 	rc = kstrtouint(str, 0, &n);
623 	*end = '=';
624 	if (rc < 0) {
625 		pr_err("Failed to parse '%s'\n", str);
626 		return 1;
627 	}
628 	str = end;
629 
630 	spin_lock(&devices_lock);
631 
632 	list_for_each(ele, &devices) {
633 		device = list_entry(ele, struct iss_net_private, device_list);
634 		if (device->index == n)
635 			break;
636 	}
637 
638 	spin_unlock(&devices_lock);
639 
640 	if (device && device->index == n) {
641 		pr_err("Device %u already configured\n", n);
642 		return 1;
643 	}
644 
645 	new = memblock_alloc(sizeof(*new), SMP_CACHE_BYTES);
646 	if (new == NULL) {
647 		pr_err("Alloc_bootmem failed\n");
648 		return 1;
649 	}
650 
651 	INIT_LIST_HEAD(&new->list);
652 	new->index = n;
653 	new->init = str + 1;
654 
655 	list_add_tail(&new->list, &eth_cmd_line);
656 	return 1;
657 }
658 
659 __setup("eth", iss_net_setup);
660 
661 /*
662  * Initialize all ISS Ethernet devices previously registered in iss_net_setup.
663  */
664 
665 static int iss_net_init(void)
666 {
667 	struct list_head *ele, *next;
668 
669 	/* Walk through all Ethernet devices specified in the command line. */
670 
671 	list_for_each_safe(ele, next, &eth_cmd_line) {
672 		struct iss_net_init *eth;
673 		eth = list_entry(ele, struct iss_net_init, list);
674 		iss_net_configure(eth->index, eth->init);
675 	}
676 
677 	return 1;
678 }
679 device_initcall(iss_net_init);
680