net/caif/caif_dev.c

   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/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 <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/cfpkt.h>
  26 #include <net/caif/cfcnfg.h>
  27
  28 MODULE_LICENSE("GPL");
  29
  30 /* Used for local tracking of the CAIF net devices */
  31 struct caif_device_entry {
  32         struct cflayer layer;
  33         struct list_head list;
  34         struct net_device *netdev;
  35         int __percpu *pcpu_refcnt;
  36 };
  37
  38 struct caif_device_entry_list {
  39         struct list_head list;
  40         /* Protects simulanous deletes in list */
  41         struct mutex lock;
  42 };
  43
  44 struct caif_net {
  45         struct cfcnfg *cfg;
  46         struct caif_device_entry_list caifdevs;
  47 };
  48
  49 static int caif_net_id;
  50
  51 struct cfcnfg *get_cfcnfg(struct net *net)
  52 {
  53         struct caif_net *caifn;
  54         BUG_ON(!net);
  55         caifn = net_generic(net, caif_net_id);
  56         BUG_ON(!caifn);
  57         return caifn->cfg;
  58 }
  59 EXPORT_SYMBOL(get_cfcnfg);
  60
  61 static struct caif_device_entry_list *caif_device_list(struct net *net)
  62 {
  63         struct caif_net *caifn;
  64         BUG_ON(!net);
  65         caifn = net_generic(net, caif_net_id);
  66         BUG_ON(!caifn);
  67         return &caifn->caifdevs;
  68 }
  69
  70 static void caifd_put(struct caif_device_entry *e)
  71 {
  72         irqsafe_cpu_dec(*e->pcpu_refcnt);
  73 }
  74
  75 static void caifd_hold(struct caif_device_entry *e)
  76 {
  77         irqsafe_cpu_inc(*e->pcpu_refcnt);
  78 }
  79
  80 static int caifd_refcnt_read(struct caif_device_entry *e)
  81 {
  82         int i, refcnt = 0;
  83         for_each_possible_cpu(i)
  84                 refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
  85         return refcnt;
  86 }
  87
  88 /* Allocate new CAIF device. */
  89 static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
  90 {
  91         struct caif_device_entry_list *caifdevs;
  92         struct caif_device_entry *caifd;
  93
  94         caifdevs = caif_device_list(dev_net(dev));
  95         BUG_ON(!caifdevs);
  96
  97         caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
  98         if (!caifd)
  99                 return NULL;
 100         caifd->pcpu_refcnt = alloc_percpu(int);
 101         if (!caifd->pcpu_refcnt) {
 102                 kfree(caifd);
 103                 return NULL;
 104         }
 105         caifd->netdev = dev;
 106         dev_hold(dev);
 107         return caifd;
 108 }
 109
 110 static struct caif_device_entry *caif_get(struct net_device *dev)
 111 {
 112         struct caif_device_entry_list *caifdevs =
 113             caif_device_list(dev_net(dev));
 114         struct caif_device_entry *caifd;
 115         BUG_ON(!caifdevs);
 116         list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
 117                 if (caifd->netdev == dev)
 118                         return caifd;
 119         }
 120         return NULL;
 121 }
 122
 123 static int transmit(struct cflayer *layer, struct cfpkt *pkt)
 124 {
 125         int err;
 126         struct caif_device_entry *caifd =
 127             container_of(layer, struct caif_device_entry, layer);
 128         struct sk_buff *skb;
 129
 130         skb = cfpkt_tonative(pkt);
 131         skb->dev = caifd->netdev;
 132
 133         err = dev_queue_xmit(skb);
 134         if (err > 0)
 135                 err = -EIO;
 136
 137         return err;
 138 }
 139
 140 /*
 141  * Stuff received packets into the CAIF stack.
 142  * On error, returns non-zero and releases the skb.
 143  */
 144 static int receive(struct sk_buff *skb, struct net_device *dev,
 145                    struct packet_type *pkttype, struct net_device *orig_dev)
 146 {
 147         struct cfpkt *pkt;
 148         struct caif_device_entry *caifd;
 149         int err;
 150
 151         pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
 152
 153         rcu_read_lock();
 154         caifd = caif_get(dev);
 155
 156         if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
 157                         !netif_oper_up(caifd->netdev)) {
 158                 rcu_read_unlock();
 159                 kfree_skb(skb);
 160                 return NET_RX_DROP;
 161         }
 162
 163         /* Hold reference to netdevice while using CAIF stack */
 164         caifd_hold(caifd);
 165         rcu_read_unlock();
 166
 167         err = caifd->layer.up->receive(caifd->layer.up, pkt);
 168
 169         /* For -EILSEQ the packet is not freed so so it now */
 170         if (err == -EILSEQ)
 171                 cfpkt_destroy(pkt);
 172
 173         /* Release reference to stack upwards */
 174         caifd_put(caifd);
 175         return 0;
 176 }
 177
 178 static struct packet_type caif_packet_type __read_mostly = {
 179         .type = cpu_to_be16(ETH_P_CAIF),
 180         .func = receive,
 181 };
 182
 183 static void dev_flowctrl(struct net_device *dev, int on)
 184 {
 185         struct caif_device_entry *caifd;
 186
 187         rcu_read_lock();
 188
 189         caifd = caif_get(dev);
 190         if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
 191                 rcu_read_unlock();
 192                 return;
 193         }
 194
 195         caifd_hold(caifd);
 196         rcu_read_unlock();
 197
 198         caifd->layer.up->ctrlcmd(caifd->layer.up,
 199                                  on ?
 200                                  _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
 201                                  _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
 202                                  caifd->layer.id);
 203         caifd_put(caifd);
 204 }
 205
 206 /* notify Caif of device events */
 207 static int caif_device_notify(struct notifier_block *me, unsigned long what,
 208                               void *arg)
 209 {
 210         struct net_device *dev = arg;
 211         struct caif_device_entry *caifd = NULL;
 212         struct caif_dev_common *caifdev;
 213         enum cfcnfg_phy_preference pref;
 214         enum cfcnfg_phy_type phy_type;
 215         struct cfcnfg *cfg;
 216         struct caif_device_entry_list *caifdevs;
 217
 218         if (dev->type != ARPHRD_CAIF)
 219                 return 0;
 220
 221         cfg = get_cfcnfg(dev_net(dev));
 222         if (cfg == NULL)
 223                 return 0;
 224
 225         caifdevs = caif_device_list(dev_net(dev));
 226
 227         switch (what) {
 228         case NETDEV_REGISTER:
 229                 caifd = caif_device_alloc(dev);
 230                 if (!caifd)
 231                         return 0;
 232
 233                 caifdev = netdev_priv(dev);
 234                 caifdev->flowctrl = dev_flowctrl;
 235
 236                 caifd->layer.transmit = transmit;
 237
 238                 if (caifdev->use_frag)
 239                         phy_type = CFPHYTYPE_FRAG;
 240                 else
 241                         phy_type = CFPHYTYPE_CAIF;
 242
 243                 switch (caifdev->link_select) {
 244                 case CAIF_LINK_HIGH_BANDW:
 245                         pref = CFPHYPREF_HIGH_BW;
 246                         break;
 247                 case CAIF_LINK_LOW_LATENCY:
 248                         pref = CFPHYPREF_LOW_LAT;
 249                         break;
 250                 default:
 251                         pref = CFPHYPREF_HIGH_BW;
 252                         break;
 253                 }
 254                 strncpy(caifd->layer.name, dev->name,
 255                         sizeof(caifd->layer.name) - 1);
 256                 caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
 257
 258                 mutex_lock(&caifdevs->lock);
 259                 list_add_rcu(&caifd->list, &caifdevs->list);
 260
 261                 cfcnfg_add_phy_layer(cfg,
 262                                      phy_type,
 263                                      dev,
 264                                      &caifd->layer,
 265                                      pref,
 266                                      caifdev->use_fcs,
 267                                      caifdev->use_stx);
 268                 mutex_unlock(&caifdevs->lock);
 269                 break;
 270
 271         case NETDEV_UP:
 272                 rcu_read_lock();
 273
 274                 caifd = caif_get(dev);
 275                 if (caifd == NULL) {
 276                         rcu_read_unlock();
 277                         break;
 278                 }
 279
 280                 cfcnfg_set_phy_state(cfg, &caifd->layer, true);
 281                 rcu_read_unlock();
 282
 283                 break;
 284
 285         case NETDEV_DOWN:
 286                 rcu_read_lock();
 287
 288                 caifd = caif_get(dev);
 289                 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
 290                         rcu_read_unlock();
 291                         return -EINVAL;
 292                 }
 293
 294                 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
 295                 caifd_hold(caifd);
 296                 rcu_read_unlock();
 297
 298                 caifd->layer.up->ctrlcmd(caifd->layer.up,
 299                                          _CAIF_CTRLCMD_PHYIF_DOWN_IND,
 300                                          caifd->layer.id);
 301                 caifd_put(caifd);
 302                 break;
 303
 304         case NETDEV_UNREGISTER:
 305                 mutex_lock(&caifdevs->lock);
 306
 307                 caifd = caif_get(dev);
 308                 if (caifd == NULL) {
 309                         mutex_unlock(&caifdevs->lock);
 310                         break;
 311                 }
 312                 list_del_rcu(&caifd->list);
 313
 314                 /*
 315                  * NETDEV_UNREGISTER is called repeatedly until all reference
 316                  * counts for the net-device are released. If references to
 317                  * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
 318                  * the next call to NETDEV_UNREGISTER.
 319                  *
 320                  * If any packets are in flight down the CAIF Stack,
 321                  * cfcnfg_del_phy_layer will return nonzero.
 322                  * If no packets are in flight, the CAIF Stack associated
 323                  * with the net-device un-registering is freed.
 324                  */
 325
 326                 if (caifd_refcnt_read(caifd) != 0 ||
 327                         cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
 328
 329                         pr_info("Wait for device inuse\n");
 330                         /* Enrole device if CAIF Stack is still in use */
 331                         list_add_rcu(&caifd->list, &caifdevs->list);
 332                         mutex_unlock(&caifdevs->lock);
 333                         break;
 334                 }
 335
 336                 synchronize_rcu();
 337                 dev_put(caifd->netdev);
 338                 free_percpu(caifd->pcpu_refcnt);
 339                 kfree(caifd);
 340
 341                 mutex_unlock(&caifdevs->lock);
 342                 break;
 343         }
 344         return 0;
 345 }
 346
 347 static struct notifier_block caif_device_notifier = {
 348         .notifier_call = caif_device_notify,
 349         .priority = 0,
 350 };
 351
 352 /* Per-namespace Caif devices handling */
 353 static int caif_init_net(struct net *net)
 354 {
 355         struct caif_net *caifn = net_generic(net, caif_net_id);
 356         BUG_ON(!caifn);
 357         INIT_LIST_HEAD(&caifn->caifdevs.list);
 358         mutex_init(&caifn->caifdevs.lock);
 359
 360         caifn->cfg = cfcnfg_create();
 361         if (!caifn->cfg) {
 362                 pr_warn("can't create cfcnfg\n");
 363                 return -ENOMEM;
 364         }
 365
 366         return 0;
 367 }
 368
 369 static void caif_exit_net(struct net *net)
 370 {
 371         struct caif_device_entry *caifd, *tmp;
 372         struct caif_device_entry_list *caifdevs =
 373             caif_device_list(net);
 374         struct cfcnfg *cfg;
 375
 376         rtnl_lock();
 377         mutex_lock(&caifdevs->lock);
 378
 379         cfg = get_cfcnfg(net);
 380         if (cfg == NULL) {
 381                 mutex_unlock(&caifdevs->lock);
 382                 return;
 383         }
 384
 385         list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
 386                 int i = 0;
 387                 list_del_rcu(&caifd->list);
 388                 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
 389
 390                 while (i < 10 &&
 391                         (caifd_refcnt_read(caifd) != 0 ||
 392                         cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
 393
 394                         pr_info("Wait for device inuse\n");
 395                         msleep(250);
 396                         i++;
 397                 }
 398                 synchronize_rcu();
 399                 dev_put(caifd->netdev);
 400                 free_percpu(caifd->pcpu_refcnt);
 401                 kfree(caifd);
 402         }
 403         cfcnfg_remove(cfg);
 404
 405         mutex_unlock(&caifdevs->lock);
 406         rtnl_unlock();
 407 }
 408
 409 static struct pernet_operations caif_net_ops = {
 410         .init = caif_init_net,
 411         .exit = caif_exit_net,
 412         .id   = &caif_net_id,
 413         .size = sizeof(struct caif_net),
 414 };
 415
 416 /* Initialize Caif devices list */
 417 static int __init caif_device_init(void)
 418 {
 419         int result;
 420
 421         result = register_pernet_device(&caif_net_ops);
 422
 423         if (result)
 424                 return result;
 425
 426         register_netdevice_notifier(&caif_device_notifier);
 427         dev_add_pack(&caif_packet_type);
 428
 429         return result;
 430 }
 431
 432 static void __exit caif_device_exit(void)
 433 {
 434         unregister_pernet_device(&caif_net_ops);
 435         unregister_netdevice_notifier(&caif_device_notifier);
 436         dev_remove_pack(&caif_packet_type);
 437 }
 438
 439 module_init(caif_device_init);
 440 module_exit(caif_device_exit);