2 * CAIF Interface registration.
3 * Copyright (C) ST-Ericsson AB 2010
4 * Author: Sjur Brendeland
5 * License terms: GNU General Public License (GPL) version 2
7 * Borrowed heavily from file: pn_dev.c. Thanks to Remi Denis-Courmont
8 * and Sakari Ailus <sakari.ailus@nokia.com>
11 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
13 #include <linux/kernel.h>
14 #include <linux/if_arp.h>
15 #include <linux/net.h>
16 #include <linux/netdevice.h>
17 #include <linux/mutex.h>
18 #include <linux/module.h>
19 #include <linux/spinlock.h>
20 #include <net/netns/generic.h>
21 #include <net/net_namespace.h>
22 #include <net/pkt_sched.h>
23 #include <net/caif/caif_device.h>
24 #include <net/caif/caif_layer.h>
25 #include <net/caif/caif_dev.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 unsigned 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);
64 EXPORT_SYMBOL(get_cfcnfg);
66 static struct caif_device_entry_list *caif_device_list(struct net *net)
68 struct caif_net *caifn;
69 caifn = net_generic(net, caif_net_id);
70 return &caifn->caifdevs;
73 static void caifd_put(struct caif_device_entry *e)
75 this_cpu_dec(*e->pcpu_refcnt);
78 static void caifd_hold(struct caif_device_entry *e)
80 this_cpu_inc(*e->pcpu_refcnt);
83 static int caifd_refcnt_read(struct caif_device_entry *e)
86 for_each_possible_cpu(i)
87 refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
91 /* Allocate new CAIF device. */
92 static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
94 struct caif_device_entry *caifd;
96 caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
99 caifd->pcpu_refcnt = alloc_percpu(int);
100 if (!caifd->pcpu_refcnt) {
109 static struct caif_device_entry *caif_get(struct net_device *dev)
111 struct caif_device_entry_list *caifdevs =
112 caif_device_list(dev_net(dev));
113 struct caif_device_entry *caifd;
115 list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
116 if (caifd->netdev == dev)
122 static void caif_flow_cb(struct sk_buff *skb)
124 struct caif_device_entry *caifd;
125 void (*dtor)(struct sk_buff *skb) = NULL;
128 WARN_ON(skb->dev == NULL);
131 caifd = caif_get(skb->dev);
133 WARN_ON(caifd == NULL);
142 spin_lock_bh(&caifd->flow_lock);
143 send_xoff = caifd->xoff;
145 dtor = caifd->xoff_skb_dtor;
147 if (WARN_ON(caifd->xoff_skb != skb))
150 caifd->xoff_skb = NULL;
151 caifd->xoff_skb_dtor = NULL;
153 spin_unlock_bh(&caifd->flow_lock);
160 ctrlcmd(caifd->layer.up,
161 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
166 static int transmit(struct cflayer *layer, struct cfpkt *pkt)
168 int err, high = 0, qlen = 0;
169 struct caif_device_entry *caifd =
170 container_of(layer, struct caif_device_entry, layer);
172 struct netdev_queue *txq;
176 skb = cfpkt_tonative(pkt);
177 skb->dev = caifd->netdev;
178 skb_reset_network_header(skb);
179 skb->protocol = htons(ETH_P_CAIF);
181 /* Check if we need to handle xoff */
182 if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE))
185 if (unlikely(caifd->xoff))
188 if (likely(!netif_queue_stopped(caifd->netdev))) {
189 /* If we run with a TX queue, check if the queue is too long*/
190 txq = netdev_get_tx_queue(skb->dev, 0);
191 qlen = qdisc_qlen(rcu_dereference_bh(txq->qdisc));
193 if (likely(qlen == 0))
196 high = (caifd->netdev->tx_queue_len * q_high) / 100;
197 if (likely(qlen < high))
201 /* Hold lock while accessing xoff */
202 spin_lock_bh(&caifd->flow_lock);
204 spin_unlock_bh(&caifd->flow_lock);
209 * Handle flow off, we do this by temporary hi-jacking this
210 * skb's destructor function, and replace it with our own
211 * flow-on callback. The callback will set flow-on and call
212 * the original destructor.
215 pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
216 netif_queue_stopped(caifd->netdev),
219 caifd->xoff_skb = skb;
220 caifd->xoff_skb_dtor = skb->destructor;
221 skb->destructor = caif_flow_cb;
222 spin_unlock_bh(&caifd->flow_lock);
224 caifd->layer.up->ctrlcmd(caifd->layer.up,
225 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
228 rcu_read_unlock_bh();
230 err = dev_queue_xmit(skb);
238 * Stuff received packets into the CAIF stack.
239 * On error, returns non-zero and releases the skb.
241 static int receive(struct sk_buff *skb, struct net_device *dev,
242 struct packet_type *pkttype, struct net_device *orig_dev)
245 struct caif_device_entry *caifd;
248 pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
251 caifd = caif_get(dev);
253 if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
254 !netif_oper_up(caifd->netdev)) {
260 /* Hold reference to netdevice while using CAIF stack */
264 err = caifd->layer.up->receive(caifd->layer.up, pkt);
266 /* For -EILSEQ the packet is not freed so so it now */
270 /* Release reference to stack upwards */
278 static struct packet_type caif_packet_type __read_mostly = {
279 .type = cpu_to_be16(ETH_P_CAIF),
283 static void dev_flowctrl(struct net_device *dev, int on)
285 struct caif_device_entry *caifd;
289 caifd = caif_get(dev);
290 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
298 caifd->layer.up->ctrlcmd(caifd->layer.up,
300 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
301 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
306 int caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
307 struct cflayer *link_support, int head_room,
308 struct cflayer **layer,
309 int (**rcv_func)(struct sk_buff *, struct net_device *,
310 struct packet_type *,
311 struct net_device *))
313 struct caif_device_entry *caifd;
314 enum cfcnfg_phy_preference pref;
315 struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
316 struct caif_device_entry_list *caifdevs;
319 caifdevs = caif_device_list(dev_net(dev));
320 caifd = caif_device_alloc(dev);
323 *layer = &caifd->layer;
324 spin_lock_init(&caifd->flow_lock);
326 switch (caifdev->link_select) {
327 case CAIF_LINK_HIGH_BANDW:
328 pref = CFPHYPREF_HIGH_BW;
330 case CAIF_LINK_LOW_LATENCY:
331 pref = CFPHYPREF_LOW_LAT;
334 pref = CFPHYPREF_HIGH_BW;
337 mutex_lock(&caifdevs->lock);
338 list_add_rcu(&caifd->list, &caifdevs->list);
340 strncpy(caifd->layer.name, dev->name,
341 sizeof(caifd->layer.name) - 1);
342 caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
343 caifd->layer.transmit = transmit;
344 res = cfcnfg_add_phy_layer(cfg,
351 mutex_unlock(&caifdevs->lock);
356 EXPORT_SYMBOL(caif_enroll_dev);
358 /* notify Caif of device events */
359 static int caif_device_notify(struct notifier_block *me, unsigned long what,
362 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
363 struct caif_device_entry *caifd = NULL;
364 struct caif_dev_common *caifdev;
366 struct cflayer *layer, *link_support;
368 struct caif_device_entry_list *caifdevs;
371 cfg = get_cfcnfg(dev_net(dev));
372 caifdevs = caif_device_list(dev_net(dev));
374 caifd = caif_get(dev);
375 if (caifd == NULL && dev->type != ARPHRD_CAIF)
379 case NETDEV_REGISTER:
383 caifdev = netdev_priv(dev);
386 if (caifdev->use_frag) {
388 link_support = cfserl_create(dev->ifindex,
391 pr_warn("Out of memory\n");
395 res = caif_enroll_dev(dev, caifdev, link_support, head_room,
398 cfserl_release(link_support);
399 caifdev->flowctrl = dev_flowctrl;
405 caifd = caif_get(dev);
412 cfcnfg_set_phy_state(cfg, &caifd->layer, true);
420 caifd = caif_get(dev);
421 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
426 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
430 caifd->layer.up->ctrlcmd(caifd->layer.up,
431 _CAIF_CTRLCMD_PHYIF_DOWN_IND,
434 spin_lock_bh(&caifd->flow_lock);
437 * Replace our xoff-destructor with original destructor.
438 * We trust that skb->destructor *always* is called before
439 * the skb reference is invalid. The hijacked SKB destructor
440 * takes the flow_lock so manipulating the skb->destructor here
443 if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
444 caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
447 caifd->xoff_skb_dtor = NULL;
448 caifd->xoff_skb = NULL;
450 spin_unlock_bh(&caifd->flow_lock);
454 case NETDEV_UNREGISTER:
455 mutex_lock(&caifdevs->lock);
457 caifd = caif_get(dev);
459 mutex_unlock(&caifdevs->lock);
462 list_del_rcu(&caifd->list);
465 * NETDEV_UNREGISTER is called repeatedly until all reference
466 * counts for the net-device are released. If references to
467 * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
468 * the next call to NETDEV_UNREGISTER.
470 * If any packets are in flight down the CAIF Stack,
471 * cfcnfg_del_phy_layer will return nonzero.
472 * If no packets are in flight, the CAIF Stack associated
473 * with the net-device un-registering is freed.
476 if (caifd_refcnt_read(caifd) != 0 ||
477 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
479 pr_info("Wait for device inuse\n");
480 /* Enrole device if CAIF Stack is still in use */
481 list_add_rcu(&caifd->list, &caifdevs->list);
482 mutex_unlock(&caifdevs->lock);
487 dev_put(caifd->netdev);
488 free_percpu(caifd->pcpu_refcnt);
491 mutex_unlock(&caifdevs->lock);
497 static struct notifier_block caif_device_notifier = {
498 .notifier_call = caif_device_notify,
502 /* Per-namespace Caif devices handling */
503 static int caif_init_net(struct net *net)
505 struct caif_net *caifn = net_generic(net, caif_net_id);
506 INIT_LIST_HEAD(&caifn->caifdevs.list);
507 mutex_init(&caifn->caifdevs.lock);
509 caifn->cfg = cfcnfg_create();
516 static void caif_exit_net(struct net *net)
518 struct caif_device_entry *caifd, *tmp;
519 struct caif_device_entry_list *caifdevs =
520 caif_device_list(net);
521 struct cfcnfg *cfg = get_cfcnfg(net);
524 mutex_lock(&caifdevs->lock);
526 list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
528 list_del_rcu(&caifd->list);
529 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
532 (caifd_refcnt_read(caifd) != 0 ||
533 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
535 pr_info("Wait for device inuse\n");
540 dev_put(caifd->netdev);
541 free_percpu(caifd->pcpu_refcnt);
546 mutex_unlock(&caifdevs->lock);
550 static struct pernet_operations caif_net_ops = {
551 .init = caif_init_net,
552 .exit = caif_exit_net,
554 .size = sizeof(struct caif_net),
557 /* Initialize Caif devices list */
558 static int __init caif_device_init(void)
562 result = register_pernet_subsys(&caif_net_ops);
567 register_netdevice_notifier(&caif_device_notifier);
568 dev_add_pack(&caif_packet_type);
573 static void __exit caif_device_exit(void)
575 unregister_netdevice_notifier(&caif_device_notifier);
576 dev_remove_pack(&caif_packet_type);
577 unregister_pernet_subsys(&caif_net_ops);
580 module_init(caif_device_init);
581 module_exit(caif_device_exit);