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
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>
12 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
14 #include <linux/kernel.h>
15 #include <linux/if_arp.h>
16 #include <linux/net.h>
17 #include <linux/netdevice.h>
18 #include <linux/mutex.h>
19 #include <linux/module.h>
20 #include <linux/spinlock.h>
21 #include <net/netns/generic.h>
22 #include <net/net_namespace.h>
23 #include <net/pkt_sched.h>
24 #include <net/caif/caif_device.h>
25 #include <net/caif/caif_layer.h>
26 #include <net/caif/cfpkt.h>
27 #include <net/caif/cfcnfg.h>
28 #include <net/caif/cfserl.h>
30 MODULE_LICENSE("GPL");
32 /* Used for local tracking of the CAIF net devices */
33 struct caif_device_entry {
35 struct list_head list;
36 struct net_device *netdev;
37 int __percpu *pcpu_refcnt;
39 struct sk_buff *xoff_skb;
40 void (*xoff_skb_dtor)(struct sk_buff *skb);
44 struct caif_device_entry_list {
45 struct list_head list;
46 /* Protects simulanous deletes in list */
52 struct caif_device_entry_list caifdevs;
55 static int caif_net_id;
56 static int q_high = 50; /* Percent */
58 struct cfcnfg *get_cfcnfg(struct net *net)
60 struct caif_net *caifn;
61 caifn = net_generic(net, caif_net_id);
66 EXPORT_SYMBOL(get_cfcnfg);
68 static struct caif_device_entry_list *caif_device_list(struct net *net)
70 struct caif_net *caifn;
71 caifn = net_generic(net, caif_net_id);
74 return &caifn->caifdevs;
77 static void caifd_put(struct caif_device_entry *e)
79 this_cpu_dec(*e->pcpu_refcnt);
82 static void caifd_hold(struct caif_device_entry *e)
84 this_cpu_inc(*e->pcpu_refcnt);
87 static int caifd_refcnt_read(struct caif_device_entry *e)
90 for_each_possible_cpu(i)
91 refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
95 /* Allocate new CAIF device. */
96 static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
98 struct caif_device_entry_list *caifdevs;
99 struct caif_device_entry *caifd;
101 caifdevs = caif_device_list(dev_net(dev));
105 caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
108 caifd->pcpu_refcnt = alloc_percpu(int);
109 if (!caifd->pcpu_refcnt) {
118 static struct caif_device_entry *caif_get(struct net_device *dev)
120 struct caif_device_entry_list *caifdevs =
121 caif_device_list(dev_net(dev));
122 struct caif_device_entry *caifd;
126 list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
127 if (caifd->netdev == dev)
133 void caif_flow_cb(struct sk_buff *skb)
135 struct caif_device_entry *caifd;
136 void (*dtor)(struct sk_buff *skb) = NULL;
139 WARN_ON(skb->dev == NULL);
142 caifd = caif_get(skb->dev);
146 spin_lock_bh(&caifd->flow_lock);
147 send_xoff = caifd->xoff;
149 if (!WARN_ON(caifd->xoff_skb_dtor == NULL)) {
150 WARN_ON(caifd->xoff_skb != skb);
151 dtor = caifd->xoff_skb_dtor;
152 caifd->xoff_skb = NULL;
153 caifd->xoff_skb_dtor = NULL;
155 spin_unlock_bh(&caifd->flow_lock);
162 ctrlcmd(caifd->layer.up,
163 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
168 static int transmit(struct cflayer *layer, struct cfpkt *pkt)
170 int err, high = 0, qlen = 0;
171 struct caif_dev_common *caifdev;
172 struct caif_device_entry *caifd =
173 container_of(layer, struct caif_device_entry, layer);
175 struct netdev_queue *txq;
179 skb = cfpkt_tonative(pkt);
180 skb->dev = caifd->netdev;
181 skb_reset_network_header(skb);
182 skb->protocol = htons(ETH_P_CAIF);
183 caifdev = netdev_priv(caifd->netdev);
185 /* Check if we need to handle xoff */
186 if (likely(caifd->netdev->tx_queue_len == 0))
189 if (unlikely(caifd->xoff))
192 if (likely(!netif_queue_stopped(caifd->netdev))) {
193 /* If we run with a TX queue, check if the queue is too long*/
194 txq = netdev_get_tx_queue(skb->dev, 0);
195 qlen = qdisc_qlen(rcu_dereference_bh(txq->qdisc));
197 if (likely(qlen == 0))
200 high = (caifd->netdev->tx_queue_len * q_high) / 100;
201 if (likely(qlen < high))
205 /* Hold lock while accessing xoff */
206 spin_lock_bh(&caifd->flow_lock);
208 spin_unlock_bh(&caifd->flow_lock);
213 * Handle flow off, we do this by temporary hi-jacking this
214 * skb's destructor function, and replace it with our own
215 * flow-on callback. The callback will set flow-on and call
216 * the original destructor.
219 pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
220 netif_queue_stopped(caifd->netdev),
223 caifd->xoff_skb = skb;
224 caifd->xoff_skb_dtor = skb->destructor;
225 skb->destructor = caif_flow_cb;
226 spin_unlock_bh(&caifd->flow_lock);
228 caifd->layer.up->ctrlcmd(caifd->layer.up,
229 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
232 rcu_read_unlock_bh();
234 err = dev_queue_xmit(skb);
242 * Stuff received packets into the CAIF stack.
243 * On error, returns non-zero and releases the skb.
245 static int receive(struct sk_buff *skb, struct net_device *dev,
246 struct packet_type *pkttype, struct net_device *orig_dev)
249 struct caif_device_entry *caifd;
252 pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
255 caifd = caif_get(dev);
257 if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
258 !netif_oper_up(caifd->netdev)) {
264 /* Hold reference to netdevice while using CAIF stack */
268 err = caifd->layer.up->receive(caifd->layer.up, pkt);
270 /* For -EILSEQ the packet is not freed so so it now */
274 /* Release reference to stack upwards */
282 static struct packet_type caif_packet_type __read_mostly = {
283 .type = cpu_to_be16(ETH_P_CAIF),
287 static void dev_flowctrl(struct net_device *dev, int on)
289 struct caif_device_entry *caifd;
293 caifd = caif_get(dev);
294 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
302 caifd->layer.up->ctrlcmd(caifd->layer.up,
304 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
305 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
310 void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
311 struct cflayer *link_support, int head_room,
312 struct cflayer **layer, int (**rcv_func)(
313 struct sk_buff *, struct net_device *,
314 struct packet_type *, struct net_device *))
316 struct caif_device_entry *caifd;
317 enum cfcnfg_phy_preference pref;
318 struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
319 struct caif_device_entry_list *caifdevs;
321 caifdevs = caif_device_list(dev_net(dev));
322 if (!cfg || !caifdevs)
324 caifd = caif_device_alloc(dev);
327 *layer = &caifd->layer;
328 spin_lock_init(&caifd->flow_lock);
330 switch (caifdev->link_select) {
331 case CAIF_LINK_HIGH_BANDW:
332 pref = CFPHYPREF_HIGH_BW;
334 case CAIF_LINK_LOW_LATENCY:
335 pref = CFPHYPREF_LOW_LAT;
338 pref = CFPHYPREF_HIGH_BW;
341 mutex_lock(&caifdevs->lock);
342 list_add_rcu(&caifd->list, &caifdevs->list);
344 strncpy(caifd->layer.name, dev->name,
345 sizeof(caifd->layer.name) - 1);
346 caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
347 caifd->layer.transmit = transmit;
348 cfcnfg_add_phy_layer(cfg,
355 mutex_unlock(&caifdevs->lock);
359 EXPORT_SYMBOL(caif_enroll_dev);
361 /* notify Caif of device events */
362 static int caif_device_notify(struct notifier_block *me, unsigned long what,
365 struct net_device *dev = arg;
366 struct caif_device_entry *caifd = NULL;
367 struct caif_dev_common *caifdev;
369 struct cflayer *layer, *link_support;
371 struct caif_device_entry_list *caifdevs;
373 cfg = get_cfcnfg(dev_net(dev));
374 caifdevs = caif_device_list(dev_net(dev));
375 if (!cfg || !caifdevs)
378 caifd = caif_get(dev);
379 if (caifd == NULL && dev->type != ARPHRD_CAIF)
383 case NETDEV_REGISTER:
387 caifdev = netdev_priv(dev);
390 if (caifdev->use_frag) {
392 link_support = cfserl_create(dev->ifindex,
395 pr_warn("Out of memory\n");
399 caif_enroll_dev(dev, caifdev, link_support, head_room,
401 caifdev->flowctrl = dev_flowctrl;
407 caifd = caif_get(dev);
414 cfcnfg_set_phy_state(cfg, &caifd->layer, true);
422 caifd = caif_get(dev);
423 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
428 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
432 caifd->layer.up->ctrlcmd(caifd->layer.up,
433 _CAIF_CTRLCMD_PHYIF_DOWN_IND,
436 spin_lock_bh(&caifd->flow_lock);
439 * Replace our xoff-destructor with original destructor.
440 * We trust that skb->destructor *always* is called before
441 * the skb reference is invalid. The hijacked SKB destructor
442 * takes the flow_lock so manipulating the skb->destructor here
445 if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
446 caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
449 caifd->xoff_skb_dtor = NULL;
450 caifd->xoff_skb = NULL;
452 spin_unlock_bh(&caifd->flow_lock);
456 case NETDEV_UNREGISTER:
457 mutex_lock(&caifdevs->lock);
459 caifd = caif_get(dev);
461 mutex_unlock(&caifdevs->lock);
464 list_del_rcu(&caifd->list);
467 * NETDEV_UNREGISTER is called repeatedly until all reference
468 * counts for the net-device are released. If references to
469 * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
470 * the next call to NETDEV_UNREGISTER.
472 * If any packets are in flight down the CAIF Stack,
473 * cfcnfg_del_phy_layer will return nonzero.
474 * If no packets are in flight, the CAIF Stack associated
475 * with the net-device un-registering is freed.
478 if (caifd_refcnt_read(caifd) != 0 ||
479 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
481 pr_info("Wait for device inuse\n");
482 /* Enrole device if CAIF Stack is still in use */
483 list_add_rcu(&caifd->list, &caifdevs->list);
484 mutex_unlock(&caifdevs->lock);
489 dev_put(caifd->netdev);
490 free_percpu(caifd->pcpu_refcnt);
493 mutex_unlock(&caifdevs->lock);
499 static struct notifier_block caif_device_notifier = {
500 .notifier_call = caif_device_notify,
504 /* Per-namespace Caif devices handling */
505 static int caif_init_net(struct net *net)
507 struct caif_net *caifn = net_generic(net, caif_net_id);
511 INIT_LIST_HEAD(&caifn->caifdevs.list);
512 mutex_init(&caifn->caifdevs.lock);
514 caifn->cfg = cfcnfg_create();
521 static void caif_exit_net(struct net *net)
523 struct caif_device_entry *caifd, *tmp;
524 struct caif_device_entry_list *caifdevs =
525 caif_device_list(net);
526 struct cfcnfg *cfg = get_cfcnfg(net);
528 if (!cfg || !caifdevs)
532 mutex_lock(&caifdevs->lock);
534 list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
536 list_del_rcu(&caifd->list);
537 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
540 (caifd_refcnt_read(caifd) != 0 ||
541 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
543 pr_info("Wait for device inuse\n");
548 dev_put(caifd->netdev);
549 free_percpu(caifd->pcpu_refcnt);
554 mutex_unlock(&caifdevs->lock);
558 static struct pernet_operations caif_net_ops = {
559 .init = caif_init_net,
560 .exit = caif_exit_net,
562 .size = sizeof(struct caif_net),
565 /* Initialize Caif devices list */
566 static int __init caif_device_init(void)
570 result = register_pernet_device(&caif_net_ops);
575 register_netdevice_notifier(&caif_device_notifier);
576 dev_add_pack(&caif_packet_type);
581 static void __exit caif_device_exit(void)
583 unregister_pernet_device(&caif_net_ops);
584 unregister_netdevice_notifier(&caif_device_notifier);
585 dev_remove_pack(&caif_packet_type);
588 module_init(caif_device_init);
589 module_exit(caif_device_exit);