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