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