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