xref: /openbmc/linux/net/caif/caif_dev.c (revision 565d76cb)
1 /*
2  * CAIF Interface registration.
3  * Copyright (C) ST-Ericsson AB 2010
4  * Author:	Sjur Brendeland/sjur.brandeland@stericsson.com
5  * License terms: GNU General Public License (GPL) version 2
6  *
7  * Borrowed heavily from file: pn_dev.c. Thanks to
8  *  Remi Denis-Courmont <remi.denis-courmont@nokia.com>
9  *  and Sakari Ailus <sakari.ailus@nokia.com>
10  */
11 
12 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
13 
14 #include <linux/version.h>
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/if_arp.h>
18 #include <linux/net.h>
19 #include <linux/netdevice.h>
20 #include <linux/skbuff.h>
21 #include <linux/sched.h>
22 #include <linux/wait.h>
23 #include <net/netns/generic.h>
24 #include <net/net_namespace.h>
25 #include <net/pkt_sched.h>
26 #include <net/caif/caif_device.h>
27 #include <net/caif/caif_dev.h>
28 #include <net/caif/caif_layer.h>
29 #include <net/caif/cfpkt.h>
30 #include <net/caif/cfcnfg.h>
31 
32 MODULE_LICENSE("GPL");
33 #define TIMEOUT (HZ*5)
34 
35 /* Used for local tracking of the CAIF net devices */
36 struct caif_device_entry {
37 	struct cflayer layer;
38 	struct list_head list;
39 	atomic_t in_use;
40 	atomic_t state;
41 	u16 phyid;
42 	struct net_device *netdev;
43 	wait_queue_head_t event;
44 };
45 
46 struct caif_device_entry_list {
47 	struct list_head list;
48 	/* Protects simulanous deletes in list */
49 	spinlock_t lock;
50 };
51 
52 struct caif_net {
53 	struct caif_device_entry_list caifdevs;
54 };
55 
56 static int caif_net_id;
57 static struct cfcnfg *cfg;
58 
59 static struct caif_device_entry_list *caif_device_list(struct net *net)
60 {
61 	struct caif_net *caifn;
62 	BUG_ON(!net);
63 	caifn = net_generic(net, caif_net_id);
64 	BUG_ON(!caifn);
65 	return &caifn->caifdevs;
66 }
67 
68 /* Allocate new CAIF device. */
69 static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
70 {
71 	struct caif_device_entry_list *caifdevs;
72 	struct caif_device_entry *caifd;
73 	caifdevs = caif_device_list(dev_net(dev));
74 	BUG_ON(!caifdevs);
75 	caifd = kzalloc(sizeof(*caifd), GFP_ATOMIC);
76 	if (!caifd)
77 		return NULL;
78 	caifd->netdev = dev;
79 	list_add(&caifd->list, &caifdevs->list);
80 	init_waitqueue_head(&caifd->event);
81 	return caifd;
82 }
83 
84 static struct caif_device_entry *caif_get(struct net_device *dev)
85 {
86 	struct caif_device_entry_list *caifdevs =
87 	    caif_device_list(dev_net(dev));
88 	struct caif_device_entry *caifd;
89 	BUG_ON(!caifdevs);
90 	list_for_each_entry(caifd, &caifdevs->list, list) {
91 		if (caifd->netdev == dev)
92 			return caifd;
93 	}
94 	return NULL;
95 }
96 
97 static void caif_device_destroy(struct net_device *dev)
98 {
99 	struct caif_device_entry_list *caifdevs =
100 	    caif_device_list(dev_net(dev));
101 	struct caif_device_entry *caifd;
102 	ASSERT_RTNL();
103 	if (dev->type != ARPHRD_CAIF)
104 		return;
105 
106 	spin_lock_bh(&caifdevs->lock);
107 	caifd = caif_get(dev);
108 	if (caifd == NULL) {
109 		spin_unlock_bh(&caifdevs->lock);
110 		return;
111 	}
112 
113 	list_del(&caifd->list);
114 	spin_unlock_bh(&caifdevs->lock);
115 
116 	kfree(caifd);
117 }
118 
119 static int transmit(struct cflayer *layer, struct cfpkt *pkt)
120 {
121 	struct caif_device_entry *caifd =
122 	    container_of(layer, struct caif_device_entry, layer);
123 	struct sk_buff *skb, *skb2;
124 	int ret = -EINVAL;
125 	skb = cfpkt_tonative(pkt);
126 	skb->dev = caifd->netdev;
127 	/*
128 	 * Don't allow SKB to be destroyed upon error, but signal resend
129 	 * notification to clients. We can't rely on the return value as
130 	 * congestion (NET_XMIT_CN) sometimes drops the packet, sometimes don't.
131 	 */
132 	if (netif_queue_stopped(caifd->netdev))
133 		return -EAGAIN;
134 	skb2 = skb_get(skb);
135 
136 	ret = dev_queue_xmit(skb2);
137 
138 	if (!ret)
139 		kfree_skb(skb);
140 	else
141 		return -EAGAIN;
142 
143 	return 0;
144 }
145 
146 static int modemcmd(struct cflayer *layr, enum caif_modemcmd ctrl)
147 {
148 	struct caif_device_entry *caifd;
149 	struct caif_dev_common *caifdev;
150 	caifd = container_of(layr, struct caif_device_entry, layer);
151 	caifdev = netdev_priv(caifd->netdev);
152 	if (ctrl == _CAIF_MODEMCMD_PHYIF_USEFULL) {
153 		atomic_set(&caifd->in_use, 1);
154 		wake_up_interruptible(&caifd->event);
155 
156 	} else if (ctrl == _CAIF_MODEMCMD_PHYIF_USELESS) {
157 		atomic_set(&caifd->in_use, 0);
158 		wake_up_interruptible(&caifd->event);
159 	}
160 	return 0;
161 }
162 
163 /*
164  * Stuff received packets to associated sockets.
165  * On error, returns non-zero and releases the skb.
166  */
167 static int receive(struct sk_buff *skb, struct net_device *dev,
168 		   struct packet_type *pkttype, struct net_device *orig_dev)
169 {
170 	struct net *net;
171 	struct cfpkt *pkt;
172 	struct caif_device_entry *caifd;
173 	net = dev_net(dev);
174 	pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
175 	caifd = caif_get(dev);
176 	if (!caifd || !caifd->layer.up || !caifd->layer.up->receive)
177 		return NET_RX_DROP;
178 
179 	if (caifd->layer.up->receive(caifd->layer.up, pkt))
180 		return NET_RX_DROP;
181 
182 	return 0;
183 }
184 
185 static struct packet_type caif_packet_type __read_mostly = {
186 	.type = cpu_to_be16(ETH_P_CAIF),
187 	.func = receive,
188 };
189 
190 static void dev_flowctrl(struct net_device *dev, int on)
191 {
192 	struct caif_device_entry *caifd = caif_get(dev);
193 	if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
194 		return;
195 
196 	caifd->layer.up->ctrlcmd(caifd->layer.up,
197 				 on ?
198 				 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
199 				 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
200 				 caifd->layer.id);
201 }
202 
203 /* notify Caif of device events */
204 static int caif_device_notify(struct notifier_block *me, unsigned long what,
205 			      void *arg)
206 {
207 	struct net_device *dev = arg;
208 	struct caif_device_entry *caifd = NULL;
209 	struct caif_dev_common *caifdev;
210 	enum cfcnfg_phy_preference pref;
211 	int res = -EINVAL;
212 	enum cfcnfg_phy_type phy_type;
213 
214 	if (dev->type != ARPHRD_CAIF)
215 		return 0;
216 
217 	switch (what) {
218 	case NETDEV_REGISTER:
219 		netdev_info(dev, "register\n");
220 		caifd = caif_device_alloc(dev);
221 		if (caifd == NULL)
222 			break;
223 		caifdev = netdev_priv(dev);
224 		caifdev->flowctrl = dev_flowctrl;
225 		atomic_set(&caifd->state, what);
226 		res = 0;
227 		break;
228 
229 	case NETDEV_UP:
230 		netdev_info(dev, "up\n");
231 		caifd = caif_get(dev);
232 		if (caifd == NULL)
233 			break;
234 		caifdev = netdev_priv(dev);
235 		if (atomic_read(&caifd->state) == NETDEV_UP) {
236 			netdev_info(dev, "already up\n");
237 			break;
238 		}
239 		atomic_set(&caifd->state, what);
240 		caifd->layer.transmit = transmit;
241 		caifd->layer.modemcmd = modemcmd;
242 
243 		if (caifdev->use_frag)
244 			phy_type = CFPHYTYPE_FRAG;
245 		else
246 			phy_type = CFPHYTYPE_CAIF;
247 
248 		switch (caifdev->link_select) {
249 		case CAIF_LINK_HIGH_BANDW:
250 			pref = CFPHYPREF_HIGH_BW;
251 			break;
252 		case CAIF_LINK_LOW_LATENCY:
253 			pref = CFPHYPREF_LOW_LAT;
254 			break;
255 		default:
256 			pref = CFPHYPREF_HIGH_BW;
257 			break;
258 		}
259 		dev_hold(dev);
260 		cfcnfg_add_phy_layer(get_caif_conf(),
261 				     phy_type,
262 				     dev,
263 				     &caifd->layer,
264 				     &caifd->phyid,
265 				     pref,
266 				     caifdev->use_fcs,
267 				     caifdev->use_stx);
268 		strncpy(caifd->layer.name, dev->name,
269 			sizeof(caifd->layer.name) - 1);
270 		caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
271 		break;
272 
273 	case NETDEV_GOING_DOWN:
274 		caifd = caif_get(dev);
275 		if (caifd == NULL)
276 			break;
277 		netdev_info(dev, "going down\n");
278 
279 		if (atomic_read(&caifd->state) == NETDEV_GOING_DOWN ||
280 			atomic_read(&caifd->state) == NETDEV_DOWN)
281 			break;
282 
283 		atomic_set(&caifd->state, what);
284 		if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
285 			return -EINVAL;
286 		caifd->layer.up->ctrlcmd(caifd->layer.up,
287 					 _CAIF_CTRLCMD_PHYIF_DOWN_IND,
288 					 caifd->layer.id);
289 		might_sleep();
290 		res = wait_event_interruptible_timeout(caifd->event,
291 					atomic_read(&caifd->in_use) == 0,
292 					TIMEOUT);
293 		break;
294 
295 	case NETDEV_DOWN:
296 		caifd = caif_get(dev);
297 		if (caifd == NULL)
298 			break;
299 		netdev_info(dev, "down\n");
300 		if (atomic_read(&caifd->in_use))
301 			netdev_warn(dev,
302 				    "Unregistering an active CAIF device\n");
303 		cfcnfg_del_phy_layer(get_caif_conf(), &caifd->layer);
304 		dev_put(dev);
305 		atomic_set(&caifd->state, what);
306 		break;
307 
308 	case NETDEV_UNREGISTER:
309 		caifd = caif_get(dev);
310 		if (caifd == NULL)
311 			break;
312 		netdev_info(dev, "unregister\n");
313 		atomic_set(&caifd->state, what);
314 		caif_device_destroy(dev);
315 		break;
316 	}
317 	return 0;
318 }
319 
320 static struct notifier_block caif_device_notifier = {
321 	.notifier_call = caif_device_notify,
322 	.priority = 0,
323 };
324 
325 
326 struct cfcnfg *get_caif_conf(void)
327 {
328 	return cfg;
329 }
330 EXPORT_SYMBOL(get_caif_conf);
331 
332 int caif_connect_client(struct caif_connect_request *conn_req,
333 			struct cflayer *client_layer, int *ifindex,
334 			int *headroom, int *tailroom)
335 {
336 	struct cfctrl_link_param param;
337 	int ret;
338 	ret = connect_req_to_link_param(get_caif_conf(), conn_req, &param);
339 	if (ret)
340 		return ret;
341 	/* Hook up the adaptation layer. */
342 	return cfcnfg_add_adaptation_layer(get_caif_conf(), &param,
343 					client_layer, ifindex,
344 					headroom, tailroom);
345 }
346 EXPORT_SYMBOL(caif_connect_client);
347 
348 int caif_disconnect_client(struct cflayer *adap_layer)
349 {
350        return cfcnfg_disconn_adapt_layer(get_caif_conf(), adap_layer);
351 }
352 EXPORT_SYMBOL(caif_disconnect_client);
353 
354 void caif_release_client(struct cflayer *adap_layer)
355 {
356        cfcnfg_release_adap_layer(adap_layer);
357 }
358 EXPORT_SYMBOL(caif_release_client);
359 
360 /* Per-namespace Caif devices handling */
361 static int caif_init_net(struct net *net)
362 {
363 	struct caif_net *caifn = net_generic(net, caif_net_id);
364 	INIT_LIST_HEAD(&caifn->caifdevs.list);
365 	spin_lock_init(&caifn->caifdevs.lock);
366 	return 0;
367 }
368 
369 static void caif_exit_net(struct net *net)
370 {
371 	struct net_device *dev;
372 	int res;
373 	rtnl_lock();
374 	for_each_netdev(net, dev) {
375 		if (dev->type != ARPHRD_CAIF)
376 			continue;
377 		res = dev_close(dev);
378 		caif_device_destroy(dev);
379 	}
380 	rtnl_unlock();
381 }
382 
383 static struct pernet_operations caif_net_ops = {
384 	.init = caif_init_net,
385 	.exit = caif_exit_net,
386 	.id   = &caif_net_id,
387 	.size = sizeof(struct caif_net),
388 };
389 
390 /* Initialize Caif devices list */
391 static int __init caif_device_init(void)
392 {
393 	int result;
394 	cfg = cfcnfg_create();
395 	if (!cfg) {
396 		pr_warn("can't create cfcnfg\n");
397 		goto err_cfcnfg_create_failed;
398 	}
399 	result = register_pernet_device(&caif_net_ops);
400 
401 	if (result) {
402 		kfree(cfg);
403 		cfg = NULL;
404 		return result;
405 	}
406 	dev_add_pack(&caif_packet_type);
407 	register_netdevice_notifier(&caif_device_notifier);
408 
409 	return result;
410 err_cfcnfg_create_failed:
411 	return -ENODEV;
412 }
413 
414 static void __exit caif_device_exit(void)
415 {
416 	dev_remove_pack(&caif_packet_type);
417 	unregister_pernet_device(&caif_net_ops);
418 	unregister_netdevice_notifier(&caif_device_notifier);
419 	cfcnfg_remove(cfg);
420 }
421 
422 module_init(caif_device_init);
423 module_exit(caif_device_exit);
424