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