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