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