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 	unsigned char *addr = dev->dev_addr;
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 	return;
151 
152 random:
153 	pr_info("%s: choosing a random ethernet address\n",
154 		dev->name);
155 	eth_hw_addr_random(dev);
156 }
157 
158 /* ======================= TUNTAP TRANSPORT INTERFACE ====================== */
159 
160 static int tuntap_open(struct iss_net_private *lp)
161 {
162 	struct ifreq ifr;
163 	char *dev_name = lp->tp.info.tuntap.dev_name;
164 	int err = -EINVAL;
165 	int fd;
166 
167 	fd = simc_open("/dev/net/tun", 02, 0); /* O_RDWR */
168 	if (fd < 0) {
169 		pr_err("%s: failed to open /dev/net/tun, returned %d (errno = %d)\n",
170 		       lp->dev->name, fd, errno);
171 		return fd;
172 	}
173 
174 	memset(&ifr, 0, sizeof(ifr));
175 	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
176 	strlcpy(ifr.ifr_name, dev_name, sizeof(ifr.ifr_name));
177 
178 	err = simc_ioctl(fd, TUNSETIFF, &ifr);
179 	if (err < 0) {
180 		pr_err("%s: failed to set interface %s, returned %d (errno = %d)\n",
181 		       lp->dev->name, dev_name, err, errno);
182 		simc_close(fd);
183 		return err;
184 	}
185 
186 	lp->tp.info.tuntap.fd = fd;
187 	return err;
188 }
189 
190 static void tuntap_close(struct iss_net_private *lp)
191 {
192 	simc_close(lp->tp.info.tuntap.fd);
193 	lp->tp.info.tuntap.fd = -1;
194 }
195 
196 static int tuntap_read(struct iss_net_private *lp, struct sk_buff **skb)
197 {
198 	return simc_read(lp->tp.info.tuntap.fd,
199 			(*skb)->data, (*skb)->dev->mtu + ETH_HEADER_OTHER);
200 }
201 
202 static int tuntap_write(struct iss_net_private *lp, struct sk_buff **skb)
203 {
204 	return simc_write(lp->tp.info.tuntap.fd, (*skb)->data, (*skb)->len);
205 }
206 
207 unsigned short tuntap_protocol(struct sk_buff *skb)
208 {
209 	return eth_type_trans(skb, skb->dev);
210 }
211 
212 static int tuntap_poll(struct iss_net_private *lp)
213 {
214 	return simc_poll(lp->tp.info.tuntap.fd);
215 }
216 
217 /*
218  * ethX=tuntap,[mac address],device name
219  */
220 
221 static int tuntap_probe(struct iss_net_private *lp, int index, char *init)
222 {
223 	struct net_device *dev = lp->dev;
224 	char *dev_name = NULL, *mac_str = NULL, *rem = NULL;
225 
226 	/* Transport should be 'tuntap': ethX=tuntap,mac,dev_name */
227 
228 	if (strncmp(init, TRANSPORT_TUNTAP_NAME,
229 		    sizeof(TRANSPORT_TUNTAP_NAME) - 1))
230 		return 0;
231 
232 	init += sizeof(TRANSPORT_TUNTAP_NAME) - 1;
233 	if (*init == ',') {
234 		rem = split_if_spec(init + 1, &mac_str, &dev_name);
235 		if (rem != NULL) {
236 			pr_err("%s: extra garbage on specification : '%s'\n",
237 			       dev->name, rem);
238 			return 0;
239 		}
240 	} else if (*init != '\0') {
241 		pr_err("%s: invalid argument: %s. Skipping device!\n",
242 		       dev->name, init);
243 		return 0;
244 	}
245 
246 	if (!dev_name) {
247 		pr_err("%s: missing tuntap device name\n", dev->name);
248 		return 0;
249 	}
250 
251 	strlcpy(lp->tp.info.tuntap.dev_name, dev_name,
252 		sizeof(lp->tp.info.tuntap.dev_name));
253 
254 	setup_etheraddr(dev, mac_str);
255 
256 	lp->mtu = TRANSPORT_TUNTAP_MTU;
257 
258 	lp->tp.info.tuntap.fd = -1;
259 
260 	lp->tp.open = tuntap_open;
261 	lp->tp.close = tuntap_close;
262 	lp->tp.read = tuntap_read;
263 	lp->tp.write = tuntap_write;
264 	lp->tp.protocol = tuntap_protocol;
265 	lp->tp.poll = tuntap_poll;
266 
267 	return 1;
268 }
269 
270 /* ================================ ISS NET ================================ */
271 
272 static int iss_net_rx(struct net_device *dev)
273 {
274 	struct iss_net_private *lp = netdev_priv(dev);
275 	int pkt_len;
276 	struct sk_buff *skb;
277 
278 	/* Check if there is any new data. */
279 
280 	if (lp->tp.poll(lp) == 0)
281 		return 0;
282 
283 	/* Try to allocate memory, if it fails, try again next round. */
284 
285 	skb = dev_alloc_skb(dev->mtu + 2 + ETH_HEADER_OTHER);
286 	if (skb == NULL) {
287 		lp->stats.rx_dropped++;
288 		return 0;
289 	}
290 
291 	skb_reserve(skb, 2);
292 
293 	/* Setup skb */
294 
295 	skb->dev = dev;
296 	skb_reset_mac_header(skb);
297 	pkt_len = lp->tp.read(lp, &skb);
298 	skb_put(skb, pkt_len);
299 
300 	if (pkt_len > 0) {
301 		skb_trim(skb, pkt_len);
302 		skb->protocol = lp->tp.protocol(skb);
303 
304 		lp->stats.rx_bytes += skb->len;
305 		lp->stats.rx_packets++;
306 		netif_rx_ni(skb);
307 		return pkt_len;
308 	}
309 	kfree_skb(skb);
310 	return pkt_len;
311 }
312 
313 static int iss_net_poll(void)
314 {
315 	struct list_head *ele;
316 	int err, ret = 0;
317 
318 	spin_lock(&opened_lock);
319 
320 	list_for_each(ele, &opened) {
321 		struct iss_net_private *lp;
322 
323 		lp = list_entry(ele, struct iss_net_private, opened_list);
324 
325 		if (!netif_running(lp->dev))
326 			break;
327 
328 		spin_lock(&lp->lock);
329 
330 		while ((err = iss_net_rx(lp->dev)) > 0)
331 			ret++;
332 
333 		spin_unlock(&lp->lock);
334 
335 		if (err < 0) {
336 			pr_err("Device '%s' read returned %d, shutting it down\n",
337 			       lp->dev->name, err);
338 			dev_close(lp->dev);
339 		} else {
340 			/* FIXME reactivate_fd(lp->fd, ISS_ETH_IRQ); */
341 		}
342 	}
343 
344 	spin_unlock(&opened_lock);
345 	return ret;
346 }
347 
348 
349 static void iss_net_timer(struct timer_list *t)
350 {
351 	struct iss_net_private *lp = from_timer(lp, t, timer);
352 
353 	iss_net_poll();
354 	spin_lock(&lp->lock);
355 	mod_timer(&lp->timer, jiffies + lp->timer_val);
356 	spin_unlock(&lp->lock);
357 }
358 
359 
360 static int iss_net_open(struct net_device *dev)
361 {
362 	struct iss_net_private *lp = netdev_priv(dev);
363 	int err;
364 
365 	spin_lock_bh(&lp->lock);
366 
367 	err = lp->tp.open(lp);
368 	if (err < 0)
369 		goto out;
370 
371 	netif_start_queue(dev);
372 
373 	/* clear buffer - it can happen that the host side of the interface
374 	 * is full when we get here. In this case, new data is never queued,
375 	 * SIGIOs never arrive, and the net never works.
376 	 */
377 	while ((err = iss_net_rx(dev)) > 0)
378 		;
379 
380 	spin_unlock_bh(&lp->lock);
381 	spin_lock_bh(&opened_lock);
382 	list_add(&lp->opened_list, &opened);
383 	spin_unlock_bh(&opened_lock);
384 	spin_lock_bh(&lp->lock);
385 
386 	timer_setup(&lp->timer, iss_net_timer, 0);
387 	lp->timer_val = ISS_NET_TIMER_VALUE;
388 	mod_timer(&lp->timer, jiffies + lp->timer_val);
389 
390 out:
391 	spin_unlock_bh(&lp->lock);
392 	return err;
393 }
394 
395 static int iss_net_close(struct net_device *dev)
396 {
397 	struct iss_net_private *lp = netdev_priv(dev);
398 	netif_stop_queue(dev);
399 	spin_lock_bh(&lp->lock);
400 
401 	spin_lock(&opened_lock);
402 	list_del(&opened);
403 	spin_unlock(&opened_lock);
404 
405 	del_timer_sync(&lp->timer);
406 
407 	lp->tp.close(lp);
408 
409 	spin_unlock_bh(&lp->lock);
410 	return 0;
411 }
412 
413 static int iss_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
414 {
415 	struct iss_net_private *lp = netdev_priv(dev);
416 	int len;
417 
418 	netif_stop_queue(dev);
419 	spin_lock_bh(&lp->lock);
420 
421 	len = lp->tp.write(lp, &skb);
422 
423 	if (len == skb->len) {
424 		lp->stats.tx_packets++;
425 		lp->stats.tx_bytes += skb->len;
426 		netif_trans_update(dev);
427 		netif_start_queue(dev);
428 
429 		/* this is normally done in the interrupt when tx finishes */
430 		netif_wake_queue(dev);
431 
432 	} else if (len == 0) {
433 		netif_start_queue(dev);
434 		lp->stats.tx_dropped++;
435 
436 	} else {
437 		netif_start_queue(dev);
438 		pr_err("%s: %s failed(%d)\n", dev->name, __func__, len);
439 	}
440 
441 	spin_unlock_bh(&lp->lock);
442 
443 	dev_kfree_skb(skb);
444 	return NETDEV_TX_OK;
445 }
446 
447 
448 static struct net_device_stats *iss_net_get_stats(struct net_device *dev)
449 {
450 	struct iss_net_private *lp = netdev_priv(dev);
451 	return &lp->stats;
452 }
453 
454 static void iss_net_set_multicast_list(struct net_device *dev)
455 {
456 }
457 
458 static void iss_net_tx_timeout(struct net_device *dev)
459 {
460 }
461 
462 static int iss_net_set_mac(struct net_device *dev, void *addr)
463 {
464 	struct iss_net_private *lp = netdev_priv(dev);
465 	struct sockaddr *hwaddr = addr;
466 
467 	if (!is_valid_ether_addr(hwaddr->sa_data))
468 		return -EADDRNOTAVAIL;
469 	spin_lock_bh(&lp->lock);
470 	memcpy(dev->dev_addr, hwaddr->sa_data, ETH_ALEN);
471 	spin_unlock_bh(&lp->lock);
472 	return 0;
473 }
474 
475 static int iss_net_change_mtu(struct net_device *dev, int new_mtu)
476 {
477 	return -EINVAL;
478 }
479 
480 void iss_net_user_timer_expire(struct timer_list *unused)
481 {
482 }
483 
484 
485 static struct platform_driver iss_net_driver = {
486 	.driver = {
487 		.name  = DRIVER_NAME,
488 	},
489 };
490 
491 static int driver_registered;
492 
493 static const struct net_device_ops iss_netdev_ops = {
494 	.ndo_open		= iss_net_open,
495 	.ndo_stop		= iss_net_close,
496 	.ndo_get_stats		= iss_net_get_stats,
497 	.ndo_start_xmit		= iss_net_start_xmit,
498 	.ndo_validate_addr	= eth_validate_addr,
499 	.ndo_change_mtu		= iss_net_change_mtu,
500 	.ndo_set_mac_address	= iss_net_set_mac,
501 	.ndo_tx_timeout		= iss_net_tx_timeout,
502 	.ndo_set_rx_mode	= iss_net_set_multicast_list,
503 };
504 
505 static int iss_net_configure(int index, char *init)
506 {
507 	struct net_device *dev;
508 	struct iss_net_private *lp;
509 	int err;
510 
511 	dev = alloc_etherdev(sizeof(*lp));
512 	if (dev == NULL) {
513 		pr_err("eth_configure: failed to allocate device\n");
514 		return 1;
515 	}
516 
517 	/* Initialize private element. */
518 
519 	lp = netdev_priv(dev);
520 	*lp = (struct iss_net_private) {
521 		.device_list		= LIST_HEAD_INIT(lp->device_list),
522 		.opened_list		= LIST_HEAD_INIT(lp->opened_list),
523 		.dev			= dev,
524 		.index			= index,
525 	};
526 
527 	spin_lock_init(&lp->lock);
528 	/*
529 	 * If this name ends up conflicting with an existing registered
530 	 * netdevice, that is OK, register_netdev{,ice}() will notice this
531 	 * and fail.
532 	 */
533 	snprintf(dev->name, sizeof(dev->name), "eth%d", index);
534 
535 	/*
536 	 * Try all transport protocols.
537 	 * Note: more protocols can be added by adding '&& !X_init(lp, eth)'.
538 	 */
539 
540 	if (!tuntap_probe(lp, index, init)) {
541 		pr_err("%s: invalid arguments. Skipping device!\n",
542 		       dev->name);
543 		goto errout;
544 	}
545 
546 	pr_info("Netdevice %d (%pM)\n", index, dev->dev_addr);
547 
548 	/* sysfs register */
549 
550 	if (!driver_registered) {
551 		platform_driver_register(&iss_net_driver);
552 		driver_registered = 1;
553 	}
554 
555 	spin_lock(&devices_lock);
556 	list_add(&lp->device_list, &devices);
557 	spin_unlock(&devices_lock);
558 
559 	lp->pdev.id = index;
560 	lp->pdev.name = DRIVER_NAME;
561 	platform_device_register(&lp->pdev);
562 	SET_NETDEV_DEV(dev, &lp->pdev.dev);
563 
564 	dev->netdev_ops = &iss_netdev_ops;
565 	dev->mtu = lp->mtu;
566 	dev->watchdog_timeo = (HZ >> 1);
567 	dev->irq = -1;
568 
569 	rtnl_lock();
570 	err = register_netdevice(dev);
571 	rtnl_unlock();
572 
573 	if (err) {
574 		pr_err("%s: error registering net device!\n", dev->name);
575 		/* XXX: should we call ->remove() here? */
576 		free_netdev(dev);
577 		return 1;
578 	}
579 
580 	timer_setup(&lp->tl, iss_net_user_timer_expire, 0);
581 
582 	return 0;
583 
584 errout:
585 	/* FIXME: unregister; free, etc.. */
586 	return -EIO;
587 }
588 
589 /* ------------------------------------------------------------------------- */
590 
591 /* Filled in during early boot */
592 
593 struct list_head eth_cmd_line = LIST_HEAD_INIT(eth_cmd_line);
594 
595 struct iss_net_init {
596 	struct list_head list;
597 	char *init;		/* init string */
598 	int index;
599 };
600 
601 /*
602  * Parse the command line and look for 'ethX=...' fields, and register all
603  * those fields. They will be later initialized in iss_net_init.
604  */
605 
606 static int __init iss_net_setup(char *str)
607 {
608 	struct iss_net_private *device = NULL;
609 	struct iss_net_init *new;
610 	struct list_head *ele;
611 	char *end;
612 	int rc;
613 	unsigned n;
614 
615 	end = strchr(str, '=');
616 	if (!end) {
617 		pr_err("Expected '=' after device number\n");
618 		return 1;
619 	}
620 	*end = 0;
621 	rc = kstrtouint(str, 0, &n);
622 	*end = '=';
623 	if (rc < 0) {
624 		pr_err("Failed to parse '%s'\n", str);
625 		return 1;
626 	}
627 	str = end;
628 
629 	spin_lock(&devices_lock);
630 
631 	list_for_each(ele, &devices) {
632 		device = list_entry(ele, struct iss_net_private, device_list);
633 		if (device->index == n)
634 			break;
635 	}
636 
637 	spin_unlock(&devices_lock);
638 
639 	if (device && device->index == n) {
640 		pr_err("Device %u already configured\n", n);
641 		return 1;
642 	}
643 
644 	new = memblock_alloc(sizeof(*new), SMP_CACHE_BYTES);
645 	if (new == NULL) {
646 		pr_err("Alloc_bootmem failed\n");
647 		return 1;
648 	}
649 
650 	INIT_LIST_HEAD(&new->list);
651 	new->index = n;
652 	new->init = str + 1;
653 
654 	list_add_tail(&new->list, &eth_cmd_line);
655 	return 1;
656 }
657 
658 __setup("eth", iss_net_setup);
659 
660 /*
661  * Initialize all ISS Ethernet devices previously registered in iss_net_setup.
662  */
663 
664 static int iss_net_init(void)
665 {
666 	struct list_head *ele, *next;
667 
668 	/* Walk through all Ethernet devices specified in the command line. */
669 
670 	list_for_each_safe(ele, next, &eth_cmd_line) {
671 		struct iss_net_init *eth;
672 		eth = list_entry(ele, struct iss_net_init, list);
673 		iss_net_configure(eth->index, eth->init);
674 	}
675 
676 	return 1;
677 }
678 device_initcall(iss_net_init);
679