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
47struct tuntap_info {
48	char dev_name[IFNAMSIZ];
49	int fd;
50};
51
52/* ------------------------------------------------------------------------- */
53
54
55struct iss_net_private;
56
57struct 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
68struct 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
94static 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
121static 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
149random:
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
157static 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
187static 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
193static 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
199static 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
204static unsigned short tuntap_protocol(struct sk_buff *skb)
205{
206	return eth_type_trans(skb, skb->dev);
207}
208
209static int tuntap_poll(struct iss_net_private *lp)
210{
211	return simc_poll(lp->tp.info.tuntap.fd);
212}
213
214static 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
227static 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
272static 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
317static 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
339static 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
348static 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
373static 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
384static 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
421static 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
431static void iss_net_set_multicast_list(struct net_device *dev)
432{
433}
434
435static void iss_net_tx_timeout(struct net_device *dev, unsigned int txqueue)
436{
437}
438
439static int iss_net_change_mtu(struct net_device *dev, int new_mtu)
440{
441	return -EINVAL;
442}
443
444static void iss_net_user_timer_expire(struct timer_list *unused)
445{
446}
447
448
449static struct platform_driver iss_net_driver = {
450	.driver = {
451		.name  = DRIVER_NAME,
452	},
453};
454
455static int driver_registered;
456
457static 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
469static 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
478static 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
552err_free_netdev:
553	free_netdev(dev);
554}
555
556/* ------------------------------------------------------------------------- */
557
558/* Filled in during early boot */
559
560struct list_head eth_cmd_line = LIST_HEAD_INIT(eth_cmd_line);
561
562struct 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
573static 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
627static 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}
641device_initcall(iss_net_init);
642