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 
42 /* We currently only support the TUNTAP transport protocol. */
43 
44 #define TRANSPORT_TUNTAP_NAME "tuntap"
45 #define TRANSPORT_TUNTAP_MTU ETH_MAX_PACKET
46 
47 struct tuntap_info {
48 	char dev_name[IFNAMSIZ];
49 	int fd;
50 };
51 
52 /* ------------------------------------------------------------------------- */
53 
54 
55 struct iss_net_private;
56 
57 struct iss_net_ops {
58 	int (*open)(struct iss_net_private *lp);
59 	void (*close)(struct iss_net_private *lp);
60 	int (*read)(struct iss_net_private *lp, struct sk_buff **skb);
61 	int (*write)(struct iss_net_private *lp, struct sk_buff **skb);
62 	unsigned short (*protocol)(struct sk_buff *skb);
63 	int (*poll)(struct iss_net_private *lp);
64 };
65 
66 /* This structure contains out private information for the driver. */
67 
68 struct iss_net_private {
69 	spinlock_t lock;
70 	struct net_device *dev;
71 	struct platform_device pdev;
72 	struct timer_list tl;
73 	struct rtnl_link_stats64 stats;
74 
75 	struct timer_list timer;
76 	unsigned int timer_val;
77 
78 	int index;
79 	int mtu;
80 
81 	struct {
82 		union {
83 			struct tuntap_info tuntap;
84 		} info;
85 
86 		const struct iss_net_ops *net_ops;
87 	} tp;
88 
89 };
90 
91 /* ================================ HELPERS ================================ */
92 
93 
94 static char *split_if_spec(char *str, ...)
95 {
96 	char **arg, *end;
97 	va_list ap;
98 
99 	va_start(ap, str);
100 	while ((arg = va_arg(ap, char**)) != NULL) {
101 		if (*str == '\0') {
102 			va_end(ap);
103 			return NULL;
104 		}
105 		end = strchr(str, ',');
106 		if (end != str)
107 			*arg = str;
108 		if (end == NULL) {
109 			va_end(ap);
110 			return NULL;
111 		}
112 		*end++ = '\0';
113 		str = end;
114 	}
115 	va_end(ap);
116 	return str;
117 }
118 
119 /* Set Ethernet address of the specified device. */
120 
121 static void setup_etheraddr(struct net_device *dev, char *str)
122 {
123 	u8 addr[ETH_ALEN];
124 
125 	if (str == NULL)
126 		goto random;
127 
128 	if (!mac_pton(str, addr)) {
129 		pr_err("%s: failed to parse '%s' as an ethernet address\n",
130 		       dev->name, str);
131 		goto random;
132 	}
133 	if (is_multicast_ether_addr(addr)) {
134 		pr_err("%s: attempt to assign a multicast ethernet address\n",
135 		       dev->name);
136 		goto random;
137 	}
138 	if (!is_valid_ether_addr(addr)) {
139 		pr_err("%s: attempt to assign an invalid ethernet address\n",
140 		       dev->name);
141 		goto random;
142 	}
143 	if (!is_local_ether_addr(addr))
144 		pr_warn("%s: assigning a globally valid ethernet address\n",
145 			dev->name);
146 	eth_hw_addr_set(dev, addr);
147 	return;
148 
149 random:
150 	pr_info("%s: choosing a random ethernet address\n",
151 		dev->name);
152 	eth_hw_addr_random(dev);
153 }
154 
155 /* ======================= TUNTAP TRANSPORT INTERFACE ====================== */
156 
157 static int tuntap_open(struct iss_net_private *lp)
158 {
159 	struct ifreq ifr;
160 	char *dev_name = lp->tp.info.tuntap.dev_name;
161 	int err = -EINVAL;
162 	int fd;
163 
164 	fd = simc_open("/dev/net/tun", 02, 0); /* O_RDWR */
165 	if (fd < 0) {
166 		pr_err("%s: failed to open /dev/net/tun, returned %d (errno = %d)\n",
167 		       lp->dev->name, fd, errno);
168 		return fd;
169 	}
170 
171 	memset(&ifr, 0, sizeof(ifr));
172 	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
173 	strscpy(ifr.ifr_name, dev_name, sizeof(ifr.ifr_name));
174 
175 	err = simc_ioctl(fd, TUNSETIFF, &ifr);
176 	if (err < 0) {
177 		pr_err("%s: failed to set interface %s, returned %d (errno = %d)\n",
178 		       lp->dev->name, dev_name, err, errno);
179 		simc_close(fd);
180 		return err;
181 	}
182 
183 	lp->tp.info.tuntap.fd = fd;
184 	return err;
185 }
186 
187 static void tuntap_close(struct iss_net_private *lp)
188 {
189 	simc_close(lp->tp.info.tuntap.fd);
190 	lp->tp.info.tuntap.fd = -1;
191 }
192 
193 static int tuntap_read(struct iss_net_private *lp, struct sk_buff **skb)
194 {
195 	return simc_read(lp->tp.info.tuntap.fd,
196 			(*skb)->data, (*skb)->dev->mtu + ETH_HEADER_OTHER);
197 }
198 
199 static int tuntap_write(struct iss_net_private *lp, struct sk_buff **skb)
200 {
201 	return simc_write(lp->tp.info.tuntap.fd, (*skb)->data, (*skb)->len);
202 }
203 
204 unsigned short tuntap_protocol(struct sk_buff *skb)
205 {
206 	return eth_type_trans(skb, skb->dev);
207 }
208 
209 static int tuntap_poll(struct iss_net_private *lp)
210 {
211 	return simc_poll(lp->tp.info.tuntap.fd);
212 }
213 
214 static const struct iss_net_ops tuntap_ops = {
215 	.open		= tuntap_open,
216 	.close		= tuntap_close,
217 	.read		= tuntap_read,
218 	.write		= tuntap_write,
219 	.protocol	= tuntap_protocol,
220 	.poll		= tuntap_poll,
221 };
222 
223 /*
224  * ethX=tuntap,[mac address],device name
225  */
226 
227 static int tuntap_probe(struct iss_net_private *lp, int index, char *init)
228 {
229 	struct net_device *dev = lp->dev;
230 	char *dev_name = NULL, *mac_str = NULL, *rem = NULL;
231 
232 	/* Transport should be 'tuntap': ethX=tuntap,mac,dev_name */
233 
234 	if (strncmp(init, TRANSPORT_TUNTAP_NAME,
235 		    sizeof(TRANSPORT_TUNTAP_NAME) - 1))
236 		return 0;
237 
238 	init += sizeof(TRANSPORT_TUNTAP_NAME) - 1;
239 	if (*init == ',') {
240 		rem = split_if_spec(init + 1, &mac_str, &dev_name, NULL);
241 		if (rem != NULL) {
242 			pr_err("%s: extra garbage on specification : '%s'\n",
243 			       dev->name, rem);
244 			return 0;
245 		}
246 	} else if (*init != '\0') {
247 		pr_err("%s: invalid argument: %s. Skipping device!\n",
248 		       dev->name, init);
249 		return 0;
250 	}
251 
252 	if (!dev_name) {
253 		pr_err("%s: missing tuntap device name\n", dev->name);
254 		return 0;
255 	}
256 
257 	strscpy(lp->tp.info.tuntap.dev_name, dev_name,
258 		sizeof(lp->tp.info.tuntap.dev_name));
259 
260 	setup_etheraddr(dev, mac_str);
261 
262 	lp->mtu = TRANSPORT_TUNTAP_MTU;
263 
264 	lp->tp.info.tuntap.fd = -1;
265 	lp->tp.net_ops = &tuntap_ops;
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.net_ops->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 		spin_lock_bh(&lp->lock);
288 		lp->stats.rx_dropped++;
289 		spin_unlock_bh(&lp->lock);
290 		return 0;
291 	}
292 
293 	skb_reserve(skb, 2);
294 
295 	/* Setup skb */
296 
297 	skb->dev = dev;
298 	skb_reset_mac_header(skb);
299 	pkt_len = lp->tp.net_ops->read(lp, &skb);
300 	skb_put(skb, pkt_len);
301 
302 	if (pkt_len > 0) {
303 		skb_trim(skb, pkt_len);
304 		skb->protocol = lp->tp.net_ops->protocol(skb);
305 
306 		spin_lock_bh(&lp->lock);
307 		lp->stats.rx_bytes += skb->len;
308 		lp->stats.rx_packets++;
309 		spin_unlock_bh(&lp->lock);
310 		netif_rx(skb);
311 		return pkt_len;
312 	}
313 	kfree_skb(skb);
314 	return pkt_len;
315 }
316 
317 static int iss_net_poll(struct iss_net_private *lp)
318 {
319 	int err, ret = 0;
320 
321 	if (!netif_running(lp->dev))
322 		return 0;
323 
324 	while ((err = iss_net_rx(lp->dev)) > 0)
325 		ret++;
326 
327 	if (err < 0) {
328 		pr_err("Device '%s' read returned %d, shutting it down\n",
329 		       lp->dev->name, err);
330 		dev_close(lp->dev);
331 	} else {
332 		/* FIXME reactivate_fd(lp->fd, ISS_ETH_IRQ); */
333 	}
334 
335 	return ret;
336 }
337 
338 
339 static void iss_net_timer(struct timer_list *t)
340 {
341 	struct iss_net_private *lp = from_timer(lp, t, timer);
342 
343 	iss_net_poll(lp);
344 	mod_timer(&lp->timer, jiffies + lp->timer_val);
345 }
346 
347 
348 static int iss_net_open(struct net_device *dev)
349 {
350 	struct iss_net_private *lp = netdev_priv(dev);
351 	int err;
352 
353 	err = lp->tp.net_ops->open(lp);
354 	if (err < 0)
355 		return err;
356 
357 	netif_start_queue(dev);
358 
359 	/* clear buffer - it can happen that the host side of the interface
360 	 * is full when we get here. In this case, new data is never queued,
361 	 * SIGIOs never arrive, and the net never works.
362 	 */
363 	while ((err = iss_net_rx(dev)) > 0)
364 		;
365 
366 	timer_setup(&lp->timer, iss_net_timer, 0);
367 	lp->timer_val = ISS_NET_TIMER_VALUE;
368 	mod_timer(&lp->timer, jiffies + lp->timer_val);
369 
370 	return err;
371 }
372 
373 static int iss_net_close(struct net_device *dev)
374 {
375 	struct iss_net_private *lp = netdev_priv(dev);
376 
377 	netif_stop_queue(dev);
378 	del_timer_sync(&lp->timer);
379 	lp->tp.net_ops->close(lp);
380 
381 	return 0;
382 }
383 
384 static int iss_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
385 {
386 	struct iss_net_private *lp = netdev_priv(dev);
387 	int len;
388 
389 	netif_stop_queue(dev);
390 
391 	len = lp->tp.net_ops->write(lp, &skb);
392 
393 	if (len == skb->len) {
394 		spin_lock_bh(&lp->lock);
395 		lp->stats.tx_packets++;
396 		lp->stats.tx_bytes += skb->len;
397 		spin_unlock_bh(&lp->lock);
398 		netif_trans_update(dev);
399 		netif_start_queue(dev);
400 
401 		/* this is normally done in the interrupt when tx finishes */
402 		netif_wake_queue(dev);
403 
404 	} else if (len == 0) {
405 		netif_start_queue(dev);
406 		spin_lock_bh(&lp->lock);
407 		lp->stats.tx_dropped++;
408 		spin_unlock_bh(&lp->lock);
409 
410 	} else {
411 		netif_start_queue(dev);
412 		pr_err("%s: %s failed(%d)\n", dev->name, __func__, len);
413 	}
414 
415 
416 	dev_kfree_skb(skb);
417 	return NETDEV_TX_OK;
418 }
419 
420 
421 static void iss_net_get_stats64(struct net_device *dev,
422 				struct rtnl_link_stats64 *stats)
423 {
424 	struct iss_net_private *lp = netdev_priv(dev);
425 
426 	spin_lock_bh(&lp->lock);
427 	*stats = lp->stats;
428 	spin_unlock_bh(&lp->lock);
429 }
430 
431 static void iss_net_set_multicast_list(struct net_device *dev)
432 {
433 }
434 
435 static void iss_net_tx_timeout(struct net_device *dev, unsigned int txqueue)
436 {
437 }
438 
439 static int iss_net_change_mtu(struct net_device *dev, int new_mtu)
440 {
441 	return -EINVAL;
442 }
443 
444 void iss_net_user_timer_expire(struct timer_list *unused)
445 {
446 }
447 
448 
449 static struct platform_driver iss_net_driver = {
450 	.driver = {
451 		.name  = DRIVER_NAME,
452 	},
453 };
454 
455 static int driver_registered;
456 
457 static const struct net_device_ops iss_netdev_ops = {
458 	.ndo_open		= iss_net_open,
459 	.ndo_stop		= iss_net_close,
460 	.ndo_get_stats64	= iss_net_get_stats64,
461 	.ndo_start_xmit		= iss_net_start_xmit,
462 	.ndo_validate_addr	= eth_validate_addr,
463 	.ndo_change_mtu		= iss_net_change_mtu,
464 	.ndo_set_mac_address	= eth_mac_addr,
465 	.ndo_tx_timeout		= iss_net_tx_timeout,
466 	.ndo_set_rx_mode	= iss_net_set_multicast_list,
467 };
468 
469 static void iss_net_pdev_release(struct device *dev)
470 {
471 	struct platform_device *pdev = to_platform_device(dev);
472 	struct iss_net_private *lp =
473 		container_of(pdev, struct iss_net_private, pdev);
474 
475 	free_netdev(lp->dev);
476 }
477 
478 static void iss_net_configure(int index, char *init)
479 {
480 	struct net_device *dev;
481 	struct iss_net_private *lp;
482 
483 	dev = alloc_etherdev(sizeof(*lp));
484 	if (dev == NULL) {
485 		pr_err("eth_configure: failed to allocate device\n");
486 		return;
487 	}
488 
489 	/* Initialize private element. */
490 
491 	lp = netdev_priv(dev);
492 	*lp = (struct iss_net_private) {
493 		.dev			= dev,
494 		.index			= index,
495 	};
496 
497 	spin_lock_init(&lp->lock);
498 	/*
499 	 * If this name ends up conflicting with an existing registered
500 	 * netdevice, that is OK, register_netdev{,ice}() will notice this
501 	 * and fail.
502 	 */
503 	snprintf(dev->name, sizeof(dev->name), "eth%d", index);
504 
505 	/*
506 	 * Try all transport protocols.
507 	 * Note: more protocols can be added by adding '&& !X_init(lp, eth)'.
508 	 */
509 
510 	if (!tuntap_probe(lp, index, init)) {
511 		pr_err("%s: invalid arguments. Skipping device!\n",
512 		       dev->name);
513 		goto err_free_netdev;
514 	}
515 
516 	pr_info("Netdevice %d (%pM)\n", index, dev->dev_addr);
517 
518 	/* sysfs register */
519 
520 	if (!driver_registered) {
521 		if (platform_driver_register(&iss_net_driver))
522 			goto err_free_netdev;
523 		driver_registered = 1;
524 	}
525 
526 	lp->pdev.id = index;
527 	lp->pdev.name = DRIVER_NAME;
528 	lp->pdev.dev.release = iss_net_pdev_release;
529 	if (platform_device_register(&lp->pdev))
530 		goto err_free_netdev;
531 	SET_NETDEV_DEV(dev, &lp->pdev.dev);
532 
533 	dev->netdev_ops = &iss_netdev_ops;
534 	dev->mtu = lp->mtu;
535 	dev->watchdog_timeo = (HZ >> 1);
536 	dev->irq = -1;
537 
538 	rtnl_lock();
539 	if (register_netdevice(dev)) {
540 		rtnl_unlock();
541 		pr_err("%s: error registering net device!\n", dev->name);
542 		platform_device_unregister(&lp->pdev);
543 		/* dev is freed by the iss_net_pdev_release callback */
544 		return;
545 	}
546 	rtnl_unlock();
547 
548 	timer_setup(&lp->tl, iss_net_user_timer_expire, 0);
549 
550 	return;
551 
552 err_free_netdev:
553 	free_netdev(dev);
554 }
555 
556 /* ------------------------------------------------------------------------- */
557 
558 /* Filled in during early boot */
559 
560 struct list_head eth_cmd_line = LIST_HEAD_INIT(eth_cmd_line);
561 
562 struct iss_net_init {
563 	struct list_head list;
564 	char *init;		/* init string */
565 	int index;
566 };
567 
568 /*
569  * Parse the command line and look for 'ethX=...' fields, and register all
570  * those fields. They will be later initialized in iss_net_init.
571  */
572 
573 static int __init iss_net_setup(char *str)
574 {
575 	struct iss_net_init *device = NULL;
576 	struct iss_net_init *new;
577 	struct list_head *ele;
578 	char *end;
579 	int rc;
580 	unsigned n;
581 
582 	end = strchr(str, '=');
583 	if (!end) {
584 		pr_err("Expected '=' after device number\n");
585 		return 1;
586 	}
587 	*end = 0;
588 	rc = kstrtouint(str, 0, &n);
589 	*end = '=';
590 	if (rc < 0) {
591 		pr_err("Failed to parse '%s'\n", str);
592 		return 1;
593 	}
594 	str = end;
595 
596 	list_for_each(ele, &eth_cmd_line) {
597 		device = list_entry(ele, struct iss_net_init, list);
598 		if (device->index == n)
599 			break;
600 	}
601 
602 	if (device && device->index == n) {
603 		pr_err("Device %u already configured\n", n);
604 		return 1;
605 	}
606 
607 	new = memblock_alloc(sizeof(*new), SMP_CACHE_BYTES);
608 	if (new == NULL) {
609 		pr_err("Alloc_bootmem failed\n");
610 		return 1;
611 	}
612 
613 	INIT_LIST_HEAD(&new->list);
614 	new->index = n;
615 	new->init = str + 1;
616 
617 	list_add_tail(&new->list, &eth_cmd_line);
618 	return 1;
619 }
620 
621 __setup("eth", iss_net_setup);
622 
623 /*
624  * Initialize all ISS Ethernet devices previously registered in iss_net_setup.
625  */
626 
627 static int iss_net_init(void)
628 {
629 	struct list_head *ele, *next;
630 
631 	/* Walk through all Ethernet devices specified in the command line. */
632 
633 	list_for_each_safe(ele, next, &eth_cmd_line) {
634 		struct iss_net_init *eth;
635 		eth = list_entry(ele, struct iss_net_init, list);
636 		iss_net_configure(eth->index, eth->init);
637 	}
638 
639 	return 1;
640 }
641 device_initcall(iss_net_init);
642