net/dsa/dsa2.c

   1 /*
   2  * net/dsa/dsa2.c - Hardware switch handling, binding version 2
   3  * Copyright (c) 2008-2009 Marvell Semiconductor
   4  * Copyright (c) 2013 Florian Fainelli <florian@openwrt.org>
   5  * Copyright (c) 2016 Andrew Lunn <andrew@lunn.ch>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13 #include <linux/device.h>
  14 #include <linux/err.h>
  15 #include <linux/list.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/slab.h>
  18 #include <linux/rtnetlink.h>
  19 #include <linux/of.h>
  20 #include <linux/of_net.h>
  21
  22 #include "dsa_priv.h"
  23
  24 static LIST_HEAD(dsa_tree_list);
  25 static DEFINE_MUTEX(dsa2_mutex);
  26
  27 static const struct devlink_ops dsa_devlink_ops = {
  28 };
  29
  30 static struct dsa_switch_tree *dsa_tree_find(int index)
  31 {
  32         struct dsa_switch_tree *dst;
  33
  34         list_for_each_entry(dst, &dsa_tree_list, list)
  35                 if (dst->index == index)
  36                         return dst;
  37
  38         return NULL;
  39 }
  40
  41 static struct dsa_switch_tree *dsa_tree_alloc(int index)
  42 {
  43         struct dsa_switch_tree *dst;
  44
  45         dst = kzalloc(sizeof(*dst), GFP_KERNEL);
  46         if (!dst)
  47                 return NULL;
  48
  49         dst->index = index;
  50
  51         INIT_LIST_HEAD(&dst->list);
  52         list_add_tail(&dsa_tree_list, &dst->list);
  53
  54         kref_init(&dst->refcount);
  55
  56         return dst;
  57 }
  58
  59 static void dsa_tree_free(struct dsa_switch_tree *dst)
  60 {
  61         list_del(&dst->list);
  62         kfree(dst);
  63 }
  64
  65 static struct dsa_switch_tree *dsa_tree_get(struct dsa_switch_tree *dst)
  66 {
  67         if (dst)
  68                 kref_get(&dst->refcount);
  69
  70         return dst;
  71 }
  72
  73 static struct dsa_switch_tree *dsa_tree_touch(int index)
  74 {
  75         struct dsa_switch_tree *dst;
  76
  77         dst = dsa_tree_find(index);
  78         if (dst)
  79                 return dsa_tree_get(dst);
  80         else
  81                 return dsa_tree_alloc(index);
  82 }
  83
  84 static void dsa_tree_release(struct kref *ref)
  85 {
  86         struct dsa_switch_tree *dst;
  87
  88         dst = container_of(ref, struct dsa_switch_tree, refcount);
  89
  90         dsa_tree_free(dst);
  91 }
  92
  93 static void dsa_tree_put(struct dsa_switch_tree *dst)
  94 {
  95         if (dst)
  96                 kref_put(&dst->refcount, dsa_tree_release);
  97 }
  98
  99 static bool dsa_port_is_dsa(struct dsa_port *port)
 100 {
 101         return port->type == DSA_PORT_TYPE_DSA;
 102 }
 103
 104 static bool dsa_port_is_cpu(struct dsa_port *port)
 105 {
 106         return port->type == DSA_PORT_TYPE_CPU;
 107 }
 108
 109 static bool dsa_port_is_user(struct dsa_port *dp)
 110 {
 111         return dp->type == DSA_PORT_TYPE_USER;
 112 }
 113
 114 static struct dsa_port *dsa_tree_find_port_by_node(struct dsa_switch_tree *dst,
 115                                                    struct device_node *dn)
 116 {
 117         struct dsa_switch *ds;
 118         struct dsa_port *dp;
 119         int device, port;
 120
 121         for (device = 0; device < DSA_MAX_SWITCHES; device++) {
 122                 ds = dst->ds[device];
 123                 if (!ds)
 124                         continue;
 125
 126                 for (port = 0; port < ds->num_ports; port++) {
 127                         dp = &ds->ports[port];
 128
 129                         if (dp->dn == dn)
 130                                 return dp;
 131                 }
 132         }
 133
 134         return NULL;
 135 }
 136
 137 static bool dsa_port_setup_routing_table(struct dsa_port *dp)
 138 {
 139         struct dsa_switch *ds = dp->ds;
 140         struct dsa_switch_tree *dst = ds->dst;
 141         struct device_node *dn = dp->dn;
 142         struct of_phandle_iterator it;
 143         struct dsa_port *link_dp;
 144         int err;
 145
 146         of_for_each_phandle(&it, err, dn, "link", NULL, 0) {
 147                 link_dp = dsa_tree_find_port_by_node(dst, it.node);
 148                 if (!link_dp) {
 149                         of_node_put(it.node);
 150                         return false;
 151                 }
 152
 153                 ds->rtable[link_dp->ds->index] = dp->index;
 154         }
 155
 156         return true;
 157 }
 158
 159 static bool dsa_switch_setup_routing_table(struct dsa_switch *ds)
 160 {
 161         bool complete = true;
 162         struct dsa_port *dp;
 163         int i;
 164
 165         for (i = 0; i < DSA_MAX_SWITCHES; i++)
 166                 ds->rtable[i] = DSA_RTABLE_NONE;
 167
 168         for (i = 0; i < ds->num_ports; i++) {
 169                 dp = &ds->ports[i];
 170
 171                 if (dsa_port_is_dsa(dp)) {
 172                         complete = dsa_port_setup_routing_table(dp);
 173                         if (!complete)
 174                                 break;
 175                 }
 176         }
 177
 178         return complete;
 179 }
 180
 181 static bool dsa_tree_setup_routing_table(struct dsa_switch_tree *dst)
 182 {
 183         struct dsa_switch *ds;
 184         bool complete = true;
 185         int device;
 186
 187         for (device = 0; device < DSA_MAX_SWITCHES; device++) {
 188                 ds = dst->ds[device];
 189                 if (!ds)
 190                         continue;
 191
 192                 complete = dsa_switch_setup_routing_table(ds);
 193                 if (!complete)
 194                         break;
 195         }
 196
 197         return complete;
 198 }
 199
 200 static struct dsa_port *dsa_tree_find_first_cpu(struct dsa_switch_tree *dst)
 201 {
 202         struct dsa_switch *ds;
 203         struct dsa_port *dp;
 204         int device, port;
 205
 206         for (device = 0; device < DSA_MAX_SWITCHES; device++) {
 207                 ds = dst->ds[device];
 208                 if (!ds)
 209                         continue;
 210
 211                 for (port = 0; port < ds->num_ports; port++) {
 212                         dp = &ds->ports[port];
 213
 214                         if (dsa_port_is_cpu(dp))
 215                                 return dp;
 216                 }
 217         }
 218
 219         return NULL;
 220 }
 221
 222 static int dsa_tree_setup_default_cpu(struct dsa_switch_tree *dst)
 223 {
 224         struct dsa_switch *ds;
 225         struct dsa_port *dp;
 226         int device, port;
 227
 228         /* DSA currently only supports a single CPU port */
 229         dst->cpu_dp = dsa_tree_find_first_cpu(dst);
 230         if (!dst->cpu_dp) {
 231                 pr_warn("Tree has no master device\n");
 232                 return -EINVAL;
 233         }
 234
 235         /* Assign the default CPU port to all ports of the fabric */
 236         for (device = 0; device < DSA_MAX_SWITCHES; device++) {
 237                 ds = dst->ds[device];
 238                 if (!ds)
 239                         continue;
 240
 241                 for (port = 0; port < ds->num_ports; port++) {
 242                         dp = &ds->ports[port];
 243
 244                         if (dsa_port_is_user(dp))
 245                                 dp->cpu_dp = dst->cpu_dp;
 246                 }
 247         }
 248
 249         return 0;
 250 }
 251
 252 static void dsa_tree_teardown_default_cpu(struct dsa_switch_tree *dst)
 253 {
 254         /* DSA currently only supports a single CPU port */
 255         dst->cpu_dp = NULL;
 256 }
 257
 258 static int dsa_port_setup(struct dsa_port *dp)
 259 {
 260         struct dsa_switch *ds = dp->ds;
 261         int err = 0;
 262
 263         memset(&dp->devlink_port, 0, sizeof(dp->devlink_port));
 264
 265         if (dp->type != DSA_PORT_TYPE_UNUSED)
 266                 err = devlink_port_register(ds->devlink, &dp->devlink_port,
 267                                             dp->index);
 268         if (err)
 269                 return err;
 270
 271         switch (dp->type) {
 272         case DSA_PORT_TYPE_UNUSED:
 273                 break;
 274         case DSA_PORT_TYPE_CPU:
 275         case DSA_PORT_TYPE_DSA:
 276                 err = dsa_port_fixed_link_register_of(dp);
 277                 if (err) {
 278                         dev_err(ds->dev, "failed to register fixed link for port %d.%d\n",
 279                                 ds->index, dp->index);
 280                         return err;
 281                 }
 282
 283                 break;
 284         case DSA_PORT_TYPE_USER:
 285                 err = dsa_slave_create(dp);
 286                 if (err)
 287                         dev_err(ds->dev, "failed to create slave for port %d.%d\n",
 288                                 ds->index, dp->index);
 289                 else
 290                         devlink_port_type_eth_set(&dp->devlink_port, dp->slave);
 291                 break;
 292         }
 293
 294         return 0;
 295 }
 296
 297 static void dsa_port_teardown(struct dsa_port *dp)
 298 {
 299         if (dp->type != DSA_PORT_TYPE_UNUSED)
 300                 devlink_port_unregister(&dp->devlink_port);
 301
 302         switch (dp->type) {
 303         case DSA_PORT_TYPE_UNUSED:
 304                 break;
 305         case DSA_PORT_TYPE_CPU:
 306         case DSA_PORT_TYPE_DSA:
 307                 dsa_port_fixed_link_unregister_of(dp);
 308                 break;
 309         case DSA_PORT_TYPE_USER:
 310                 if (dp->slave) {
 311                         dsa_slave_destroy(dp->slave);
 312                         dp->slave = NULL;
 313                 }
 314                 break;
 315         }
 316 }
 317
 318 static int dsa_switch_setup(struct dsa_switch *ds)
 319 {
 320         int err;
 321
 322         /* Initialize ds->phys_mii_mask before registering the slave MDIO bus
 323          * driver and before ops->setup() has run, since the switch drivers and
 324          * the slave MDIO bus driver rely on these values for probing PHY
 325          * devices or not
 326          */
 327         ds->phys_mii_mask |= dsa_user_ports(ds);
 328
 329         /* Add the switch to devlink before calling setup, so that setup can
 330          * add dpipe tables
 331          */
 332         ds->devlink = devlink_alloc(&dsa_devlink_ops, 0);
 333         if (!ds->devlink)
 334                 return -ENOMEM;
 335
 336         err = devlink_register(ds->devlink, ds->dev);
 337         if (err)
 338                 return err;
 339
 340         err = ds->ops->setup(ds);
 341         if (err < 0)
 342                 return err;
 343
 344         err = dsa_switch_register_notifier(ds);
 345         if (err)
 346                 return err;
 347
 348         if (!ds->slave_mii_bus && ds->ops->phy_read) {
 349                 ds->slave_mii_bus = devm_mdiobus_alloc(ds->dev);
 350                 if (!ds->slave_mii_bus)
 351                         return -ENOMEM;
 352
 353                 dsa_slave_mii_bus_init(ds);
 354
 355                 err = mdiobus_register(ds->slave_mii_bus);
 356                 if (err < 0)
 357                         return err;
 358         }
 359
 360         return 0;
 361 }
 362
 363 static void dsa_switch_teardown(struct dsa_switch *ds)
 364 {
 365         if (ds->slave_mii_bus && ds->ops->phy_read)
 366                 mdiobus_unregister(ds->slave_mii_bus);
 367
 368         dsa_switch_unregister_notifier(ds);
 369
 370         if (ds->devlink) {
 371                 devlink_unregister(ds->devlink);
 372                 devlink_free(ds->devlink);
 373                 ds->devlink = NULL;
 374         }
 375
 376 }
 377
 378 static int dsa_tree_setup_switches(struct dsa_switch_tree *dst)
 379 {
 380         struct dsa_switch *ds;
 381         struct dsa_port *dp;
 382         int device, port;
 383         int err;
 384
 385         for (device = 0; device < DSA_MAX_SWITCHES; device++) {
 386                 ds = dst->ds[device];
 387                 if (!ds)
 388                         continue;
 389
 390                 err = dsa_switch_setup(ds);
 391                 if (err)
 392                         return err;
 393
 394                 for (port = 0; port < ds->num_ports; port++) {
 395                         dp = &ds->ports[port];
 396
 397                         err = dsa_port_setup(dp);
 398                         if (err)
 399                                 return err;
 400                 }
 401         }
 402
 403         return 0;
 404 }
 405
 406 static void dsa_tree_teardown_switches(struct dsa_switch_tree *dst)
 407 {
 408         struct dsa_switch *ds;
 409         struct dsa_port *dp;
 410         int device, port;
 411
 412         for (device = 0; device < DSA_MAX_SWITCHES; device++) {
 413                 ds = dst->ds[device];
 414                 if (!ds)
 415                         continue;
 416
 417                 for (port = 0; port < ds->num_ports; port++) {
 418                         dp = &ds->ports[port];
 419
 420                         dsa_port_teardown(dp);
 421                 }
 422
 423                 dsa_switch_teardown(ds);
 424         }
 425 }
 426
 427 static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
 428 {
 429         struct dsa_port *cpu_dp = dst->cpu_dp;
 430         struct net_device *master = cpu_dp->master;
 431
 432         /* DSA currently supports a single pair of CPU port and master device */
 433         return dsa_master_setup(master, cpu_dp);
 434 }
 435
 436 static void dsa_tree_teardown_master(struct dsa_switch_tree *dst)
 437 {
 438         struct dsa_port *cpu_dp = dst->cpu_dp;
 439         struct net_device *master = cpu_dp->master;
 440
 441         return dsa_master_teardown(master);
 442 }
 443
 444 static int dsa_tree_setup(struct dsa_switch_tree *dst)
 445 {
 446         bool complete;
 447         int err;
 448
 449         if (dst->setup) {
 450                 pr_err("DSA: tree %d already setup! Disjoint trees?\n",
 451                        dst->index);
 452                 return -EEXIST;
 453         }
 454
 455         complete = dsa_tree_setup_routing_table(dst);
 456         if (!complete)
 457                 return 0;
 458
 459         err = dsa_tree_setup_default_cpu(dst);
 460         if (err)
 461                 return err;
 462
 463         err = dsa_tree_setup_switches(dst);
 464         if (err)
 465                 return err;
 466
 467         err = dsa_tree_setup_master(dst);
 468         if (err)
 469                 return err;
 470
 471         dst->setup = true;
 472
 473         pr_info("DSA: tree %d setup\n", dst->index);
 474
 475         return 0;
 476 }
 477
 478 static void dsa_tree_teardown(struct dsa_switch_tree *dst)
 479 {
 480         if (!dst->setup)
 481                 return;
 482
 483         dsa_tree_teardown_master(dst);
 484
 485         dsa_tree_teardown_switches(dst);
 486
 487         dsa_tree_teardown_default_cpu(dst);
 488
 489         pr_info("DSA: tree %d torn down\n", dst->index);
 490
 491         dst->setup = false;
 492 }
 493
 494 static void dsa_tree_remove_switch(struct dsa_switch_tree *dst,
 495                                    unsigned int index)
 496 {
 497         dsa_tree_teardown(dst);
 498
 499         dst->ds[index] = NULL;
 500         dsa_tree_put(dst);
 501 }
 502
 503 static int dsa_tree_add_switch(struct dsa_switch_tree *dst,
 504                                struct dsa_switch *ds)
 505 {
 506         unsigned int index = ds->index;
 507         int err;
 508
 509         if (dst->ds[index])
 510                 return -EBUSY;
 511
 512         dsa_tree_get(dst);
 513         dst->ds[index] = ds;
 514
 515         err = dsa_tree_setup(dst);
 516         if (err)
 517                 dsa_tree_remove_switch(dst, index);
 518
 519         return err;
 520 }
 521
 522 static int dsa_port_parse_user(struct dsa_port *dp, const char *name)
 523 {
 524         if (!name)
 525                 name = "eth%d";
 526
 527         dp->type = DSA_PORT_TYPE_USER;
 528         dp->name = name;
 529
 530         return 0;
 531 }
 532
 533 static int dsa_port_parse_dsa(struct dsa_port *dp)
 534 {
 535         dp->type = DSA_PORT_TYPE_DSA;
 536
 537         return 0;
 538 }
 539
 540 static int dsa_port_parse_cpu(struct dsa_port *dp, struct net_device *master)
 541 {
 542         struct dsa_switch *ds = dp->ds;
 543         struct dsa_switch_tree *dst = ds->dst;
 544         const struct dsa_device_ops *tag_ops;
 545         enum dsa_tag_protocol tag_protocol;
 546
 547         tag_protocol = ds->ops->get_tag_protocol(ds, dp->index);
 548         tag_ops = dsa_resolve_tag_protocol(tag_protocol);
 549         if (IS_ERR(tag_ops)) {
 550                 dev_warn(ds->dev, "No tagger for this switch\n");
 551                 return PTR_ERR(tag_ops);
 552         }
 553
 554         dp->type = DSA_PORT_TYPE_CPU;
 555         dp->rcv = tag_ops->rcv;
 556         dp->tag_ops = tag_ops;
 557         dp->master = master;
 558         dp->dst = dst;
 559
 560         return 0;
 561 }
 562
 563 static int dsa_port_parse_of(struct dsa_port *dp, struct device_node *dn)
 564 {
 565         struct device_node *ethernet = of_parse_phandle(dn, "ethernet", 0);
 566         const char *name = of_get_property(dn, "label", NULL);
 567         bool link = of_property_read_bool(dn, "link");
 568
 569         dp->dn = dn;
 570
 571         if (ethernet) {
 572                 struct net_device *master;
 573
 574                 master = of_find_net_device_by_node(ethernet);
 575                 if (!master)
 576                         return -EPROBE_DEFER;
 577
 578                 return dsa_port_parse_cpu(dp, master);
 579         }
 580
 581         if (link)
 582                 return dsa_port_parse_dsa(dp);
 583
 584         return dsa_port_parse_user(dp, name);
 585 }
 586
 587 static int dsa_switch_parse_ports_of(struct dsa_switch *ds,
 588                                      struct device_node *dn)
 589 {
 590         struct device_node *ports, *port;
 591         struct dsa_port *dp;
 592         u32 reg;
 593         int err;
 594
 595         ports = of_get_child_by_name(dn, "ports");
 596         if (!ports) {
 597                 dev_err(ds->dev, "no ports child node found\n");
 598                 return -EINVAL;
 599         }
 600
 601         for_each_available_child_of_node(ports, port) {
 602                 err = of_property_read_u32(port, "reg", &reg);
 603                 if (err)
 604                         return err;
 605
 606                 if (reg >= ds->num_ports)
 607                         return -EINVAL;
 608
 609                 dp = &ds->ports[reg];
 610
 611                 err = dsa_port_parse_of(dp, port);
 612                 if (err)
 613                         return err;
 614         }
 615
 616         return 0;
 617 }
 618
 619 static int dsa_switch_parse_member_of(struct dsa_switch *ds,
 620                                       struct device_node *dn)
 621 {
 622         u32 m[2] = { 0, 0 };
 623         int sz;
 624
 625         /* Don't error out if this optional property isn't found */
 626         sz = of_property_read_variable_u32_array(dn, "dsa,member", m, 2, 2);
 627         if (sz < 0 && sz != -EINVAL)
 628                 return sz;
 629
 630         ds->index = m[1];
 631         if (ds->index >= DSA_MAX_SWITCHES)
 632                 return -EINVAL;
 633
 634         ds->dst = dsa_tree_touch(m[0]);
 635         if (!ds->dst)
 636                 return -ENOMEM;
 637
 638         return 0;
 639 }
 640
 641 static int dsa_switch_parse_of(struct dsa_switch *ds, struct device_node *dn)
 642 {
 643         int err;
 644
 645         err = dsa_switch_parse_member_of(ds, dn);
 646         if (err)
 647                 return err;
 648
 649         return dsa_switch_parse_ports_of(ds, dn);
 650 }
 651
 652 static int dsa_port_parse(struct dsa_port *dp, const char *name,
 653                           struct device *dev)
 654 {
 655         if (!strcmp(name, "cpu")) {
 656                 struct net_device *master;
 657
 658                 master = dsa_dev_to_net_device(dev);
 659                 if (!master)
 660                         return -EPROBE_DEFER;
 661
 662                 dev_put(master);
 663
 664                 return dsa_port_parse_cpu(dp, master);
 665         }
 666
 667         if (!strcmp(name, "dsa"))
 668                 return dsa_port_parse_dsa(dp);
 669
 670         return dsa_port_parse_user(dp, name);
 671 }
 672
 673 static int dsa_switch_parse_ports(struct dsa_switch *ds,
 674                                   struct dsa_chip_data *cd)
 675 {
 676         bool valid_name_found = false;
 677         struct dsa_port *dp;
 678         struct device *dev;
 679         const char *name;
 680         unsigned int i;
 681         int err;
 682
 683         for (i = 0; i < DSA_MAX_PORTS; i++) {
 684                 name = cd->port_names[i];
 685                 dev = cd->netdev[i];
 686                 dp = &ds->ports[i];
 687
 688                 if (!name)
 689                         continue;
 690
 691                 err = dsa_port_parse(dp, name, dev);
 692                 if (err)
 693                         return err;
 694
 695                 valid_name_found = true;
 696         }
 697
 698         if (!valid_name_found && i == DSA_MAX_PORTS)
 699                 return -EINVAL;
 700
 701         return 0;
 702 }
 703
 704 static int dsa_switch_parse(struct dsa_switch *ds, struct dsa_chip_data *cd)
 705 {
 706         ds->cd = cd;
 707
 708         /* We don't support interconnected switches nor multiple trees via
 709          * platform data, so this is the unique switch of the tree.
 710          */
 711         ds->index = 0;
 712         ds->dst = dsa_tree_touch(0);
 713         if (!ds->dst)
 714                 return -ENOMEM;
 715
 716         return dsa_switch_parse_ports(ds, cd);
 717 }
 718
 719 static int dsa_switch_add(struct dsa_switch *ds)
 720 {
 721         struct dsa_switch_tree *dst = ds->dst;
 722
 723         return dsa_tree_add_switch(dst, ds);
 724 }
 725
 726 static int dsa_switch_probe(struct dsa_switch *ds)
 727 {
 728         struct dsa_chip_data *pdata = ds->dev->platform_data;
 729         struct device_node *np = ds->dev->of_node;
 730         int err;
 731
 732         if (np)
 733                 err = dsa_switch_parse_of(ds, np);
 734         else if (pdata)
 735                 err = dsa_switch_parse(ds, pdata);
 736         else
 737                 err = -ENODEV;
 738
 739         if (err)
 740                 return err;
 741
 742         return dsa_switch_add(ds);
 743 }
 744
 745 struct dsa_switch *dsa_switch_alloc(struct device *dev, size_t n)
 746 {
 747         size_t size = sizeof(struct dsa_switch) + n * sizeof(struct dsa_port);
 748         struct dsa_switch *ds;
 749         int i;
 750
 751         ds = devm_kzalloc(dev, size, GFP_KERNEL);
 752         if (!ds)
 753                 return NULL;
 754
 755         ds->dev = dev;
 756         ds->num_ports = n;
 757
 758         for (i = 0; i < ds->num_ports; ++i) {
 759                 ds->ports[i].index = i;
 760                 ds->ports[i].ds = ds;
 761         }
 762
 763         return ds;
 764 }
 765 EXPORT_SYMBOL_GPL(dsa_switch_alloc);
 766
 767 int dsa_register_switch(struct dsa_switch *ds)
 768 {
 769         int err;
 770
 771         mutex_lock(&dsa2_mutex);
 772         err = dsa_switch_probe(ds);
 773         dsa_tree_put(ds->dst);
 774         mutex_unlock(&dsa2_mutex);
 775
 776         return err;
 777 }
 778 EXPORT_SYMBOL_GPL(dsa_register_switch);
 779
 780 static void dsa_switch_remove(struct dsa_switch *ds)
 781 {
 782         struct dsa_switch_tree *dst = ds->dst;
 783         unsigned int index = ds->index;
 784
 785         dsa_tree_remove_switch(dst, index);
 786 }
 787
 788 void dsa_unregister_switch(struct dsa_switch *ds)
 789 {
 790         mutex_lock(&dsa2_mutex);
 791         dsa_switch_remove(ds);
 792         mutex_unlock(&dsa2_mutex);
 793 }
 794 EXPORT_SYMBOL_GPL(dsa_unregister_switch);