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 <[email protected]>
   5  * Copyright (c) 2016 Andrew Lunn <[email protected]>
   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) || dsa_port_is_dsa(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                 /* dp->index is used now as port_number. However
 276                  * CPU ports should have separate numbering
 277                  * independent from front panel port numbers.
 278                  */
 279                 devlink_port_attrs_set(&dp->devlink_port,
 280                                        DEVLINK_PORT_FLAVOUR_CPU,
 281                                        dp->index, false, 0);
 282                 err = dsa_port_link_register_of(dp);
 283                 if (err) {
 284                         dev_err(ds->dev, "failed to setup link for port %d.%d\n",
 285                                 ds->index, dp->index);
 286                         return err;
 287                 }
 288                 break;
 289         case DSA_PORT_TYPE_DSA:
 290                 /* dp->index is used now as port_number. However
 291                  * DSA ports should have separate numbering
 292                  * independent from front panel port numbers.
 293                  */
 294                 devlink_port_attrs_set(&dp->devlink_port,
 295                                        DEVLINK_PORT_FLAVOUR_DSA,
 296                                        dp->index, false, 0);
 297                 err = dsa_port_link_register_of(dp);
 298                 if (err) {
 299                         dev_err(ds->dev, "failed to setup link for port %d.%d\n",
 300                                 ds->index, dp->index);
 301                         return err;
 302                 }
 303                 break;
 304         case DSA_PORT_TYPE_USER:
 305                 devlink_port_attrs_set(&dp->devlink_port,
 306                                        DEVLINK_PORT_FLAVOUR_PHYSICAL,
 307                                        dp->index, false, 0);
 308                 err = dsa_slave_create(dp);
 309                 if (err)
 310                         dev_err(ds->dev, "failed to create slave for port %d.%d\n",
 311                                 ds->index, dp->index);
 312                 else
 313                         devlink_port_type_eth_set(&dp->devlink_port, dp->slave);
 314                 break;
 315         }
 316
 317         return 0;
 318 }
 319
 320 static void dsa_port_teardown(struct dsa_port *dp)
 321 {
 322         if (dp->type != DSA_PORT_TYPE_UNUSED)
 323                 devlink_port_unregister(&dp->devlink_port);
 324
 325         switch (dp->type) {
 326         case DSA_PORT_TYPE_UNUSED:
 327                 break;
 328         case DSA_PORT_TYPE_CPU:
 329         case DSA_PORT_TYPE_DSA:
 330                 dsa_port_link_unregister_of(dp);
 331                 break;
 332         case DSA_PORT_TYPE_USER:
 333                 if (dp->slave) {
 334                         dsa_slave_destroy(dp->slave);
 335                         dp->slave = NULL;
 336                 }
 337                 break;
 338         }
 339 }
 340
 341 static int dsa_switch_setup(struct dsa_switch *ds)
 342 {
 343         int err;
 344
 345         /* Initialize ds->phys_mii_mask before registering the slave MDIO bus
 346          * driver and before ops->setup() has run, since the switch drivers and
 347          * the slave MDIO bus driver rely on these values for probing PHY
 348          * devices or not
 349          */
 350         ds->phys_mii_mask |= dsa_user_ports(ds);
 351
 352         /* Add the switch to devlink before calling setup, so that setup can
 353          * add dpipe tables
 354          */
 355         ds->devlink = devlink_alloc(&dsa_devlink_ops, 0);
 356         if (!ds->devlink)
 357                 return -ENOMEM;
 358
 359         err = devlink_register(ds->devlink, ds->dev);
 360         if (err)
 361                 return err;
 362
 363         err = ds->ops->setup(ds);
 364         if (err < 0)
 365                 return err;
 366
 367         err = dsa_switch_register_notifier(ds);
 368         if (err)
 369                 return err;
 370
 371         if (!ds->slave_mii_bus && ds->ops->phy_read) {
 372                 ds->slave_mii_bus = devm_mdiobus_alloc(ds->dev);
 373                 if (!ds->slave_mii_bus)
 374                         return -ENOMEM;
 375
 376                 dsa_slave_mii_bus_init(ds);
 377
 378                 err = mdiobus_register(ds->slave_mii_bus);
 379                 if (err < 0)
 380                         return err;
 381         }
 382
 383         return 0;
 384 }
 385
 386 static void dsa_switch_teardown(struct dsa_switch *ds)
 387 {
 388         if (ds->slave_mii_bus && ds->ops->phy_read)
 389                 mdiobus_unregister(ds->slave_mii_bus);
 390
 391         dsa_switch_unregister_notifier(ds);
 392
 393         if (ds->devlink) {
 394                 devlink_unregister(ds->devlink);
 395                 devlink_free(ds->devlink);
 396                 ds->devlink = NULL;
 397         }
 398
 399 }
 400
 401 static int dsa_tree_setup_switches(struct dsa_switch_tree *dst)
 402 {
 403         struct dsa_switch *ds;
 404         struct dsa_port *dp;
 405         int device, port;
 406         int err;
 407
 408         for (device = 0; device < DSA_MAX_SWITCHES; device++) {
 409                 ds = dst->ds[device];
 410                 if (!ds)
 411                         continue;
 412
 413                 err = dsa_switch_setup(ds);
 414                 if (err)
 415                         return err;
 416
 417                 for (port = 0; port < ds->num_ports; port++) {
 418                         dp = &ds->ports[port];
 419
 420                         err = dsa_port_setup(dp);
 421                         if (err)
 422                                 return err;
 423                 }
 424         }
 425
 426         return 0;
 427 }
 428
 429 static void dsa_tree_teardown_switches(struct dsa_switch_tree *dst)
 430 {
 431         struct dsa_switch *ds;
 432         struct dsa_port *dp;
 433         int device, port;
 434
 435         for (device = 0; device < DSA_MAX_SWITCHES; device++) {
 436                 ds = dst->ds[device];
 437                 if (!ds)
 438                         continue;
 439
 440                 for (port = 0; port < ds->num_ports; port++) {
 441                         dp = &ds->ports[port];
 442
 443                         dsa_port_teardown(dp);
 444                 }
 445
 446                 dsa_switch_teardown(ds);
 447         }
 448 }
 449
 450 static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
 451 {
 452         struct dsa_port *cpu_dp = dst->cpu_dp;
 453         struct net_device *master = cpu_dp->master;
 454
 455         /* DSA currently supports a single pair of CPU port and master device */
 456         return dsa_master_setup(master, cpu_dp);
 457 }
 458
 459 static void dsa_tree_teardown_master(struct dsa_switch_tree *dst)
 460 {
 461         struct dsa_port *cpu_dp = dst->cpu_dp;
 462         struct net_device *master = cpu_dp->master;
 463
 464         return dsa_master_teardown(master);
 465 }
 466
 467 static int dsa_tree_setup(struct dsa_switch_tree *dst)
 468 {
 469         bool complete;
 470         int err;
 471
 472         if (dst->setup) {
 473                 pr_err("DSA: tree %d already setup! Disjoint trees?\n",
 474                        dst->index);
 475                 return -EEXIST;
 476         }
 477
 478         complete = dsa_tree_setup_routing_table(dst);
 479         if (!complete)
 480                 return 0;
 481
 482         err = dsa_tree_setup_default_cpu(dst);
 483         if (err)
 484                 return err;
 485
 486         err = dsa_tree_setup_switches(dst);
 487         if (err)
 488                 return err;
 489
 490         err = dsa_tree_setup_master(dst);
 491         if (err)
 492                 return err;
 493
 494         dst->setup = true;
 495
 496         pr_info("DSA: tree %d setup\n", dst->index);
 497
 498         return 0;
 499 }
 500
 501 static void dsa_tree_teardown(struct dsa_switch_tree *dst)
 502 {
 503         if (!dst->setup)
 504                 return;
 505
 506         dsa_tree_teardown_master(dst);
 507
 508         dsa_tree_teardown_switches(dst);
 509
 510         dsa_tree_teardown_default_cpu(dst);
 511
 512         pr_info("DSA: tree %d torn down\n", dst->index);
 513
 514         dst->setup = false;
 515 }
 516
 517 static void dsa_tree_remove_switch(struct dsa_switch_tree *dst,
 518                                    unsigned int index)
 519 {
 520         dsa_tree_teardown(dst);
 521
 522         dst->ds[index] = NULL;
 523         dsa_tree_put(dst);
 524 }
 525
 526 static int dsa_tree_add_switch(struct dsa_switch_tree *dst,
 527                                struct dsa_switch *ds)
 528 {
 529         unsigned int index = ds->index;
 530         int err;
 531
 532         if (dst->ds[index])
 533                 return -EBUSY;
 534
 535         dsa_tree_get(dst);
 536         dst->ds[index] = ds;
 537
 538         err = dsa_tree_setup(dst);
 539         if (err)
 540                 dsa_tree_remove_switch(dst, index);
 541
 542         return err;
 543 }
 544
 545 static int dsa_port_parse_user(struct dsa_port *dp, const char *name)
 546 {
 547         if (!name)
 548                 name = "eth%d";
 549
 550         dp->type = DSA_PORT_TYPE_USER;
 551         dp->name = name;
 552
 553         return 0;
 554 }
 555
 556 static int dsa_port_parse_dsa(struct dsa_port *dp)
 557 {
 558         dp->type = DSA_PORT_TYPE_DSA;
 559
 560         return 0;
 561 }
 562
 563 static int dsa_port_parse_cpu(struct dsa_port *dp, struct net_device *master)
 564 {
 565         struct dsa_switch *ds = dp->ds;
 566         struct dsa_switch_tree *dst = ds->dst;
 567         const struct dsa_device_ops *tag_ops;
 568         enum dsa_tag_protocol tag_protocol;
 569
 570         tag_protocol = ds->ops->get_tag_protocol(ds, dp->index);
 571         tag_ops = dsa_resolve_tag_protocol(tag_protocol);
 572         if (IS_ERR(tag_ops)) {
 573                 dev_warn(ds->dev, "No tagger for this switch\n");
 574                 return PTR_ERR(tag_ops);
 575         }
 576
 577         dp->type = DSA_PORT_TYPE_CPU;
 578         dp->rcv = tag_ops->rcv;
 579         dp->tag_ops = tag_ops;
 580         dp->master = master;
 581         dp->dst = dst;
 582
 583         return 0;
 584 }
 585
 586 static int dsa_port_parse_of(struct dsa_port *dp, struct device_node *dn)
 587 {
 588         struct device_node *ethernet = of_parse_phandle(dn, "ethernet", 0);
 589         const char *name = of_get_property(dn, "label", NULL);
 590         bool link = of_property_read_bool(dn, "link");
 591
 592         dp->dn = dn;
 593
 594         if (ethernet) {
 595                 struct net_device *master;
 596
 597                 master = of_find_net_device_by_node(ethernet);
 598                 if (!master)
 599                         return -EPROBE_DEFER;
 600
 601                 return dsa_port_parse_cpu(dp, master);
 602         }
 603
 604         if (link)
 605                 return dsa_port_parse_dsa(dp);
 606
 607         return dsa_port_parse_user(dp, name);
 608 }
 609
 610 static int dsa_switch_parse_ports_of(struct dsa_switch *ds,
 611                                      struct device_node *dn)
 612 {
 613         struct device_node *ports, *port;
 614         struct dsa_port *dp;
 615         u32 reg;
 616         int err;
 617
 618         ports = of_get_child_by_name(dn, "ports");
 619         if (!ports) {
 620                 dev_err(ds->dev, "no ports child node found\n");
 621                 return -EINVAL;
 622         }
 623
 624         for_each_available_child_of_node(ports, port) {
 625                 err = of_property_read_u32(port, "reg", &reg);
 626                 if (err)
 627                         return err;
 628
 629                 if (reg >= ds->num_ports)
 630                         return -EINVAL;
 631
 632                 dp = &ds->ports[reg];
 633
 634                 err = dsa_port_parse_of(dp, port);
 635                 if (err)
 636                         return err;
 637         }
 638
 639         return 0;
 640 }
 641
 642 static int dsa_switch_parse_member_of(struct dsa_switch *ds,
 643                                       struct device_node *dn)
 644 {
 645         u32 m[2] = { 0, 0 };
 646         int sz;
 647
 648         /* Don't error out if this optional property isn't found */
 649         sz = of_property_read_variable_u32_array(dn, "dsa,member", m, 2, 2);
 650         if (sz < 0 && sz != -EINVAL)
 651                 return sz;
 652
 653         ds->index = m[1];
 654         if (ds->index >= DSA_MAX_SWITCHES)
 655                 return -EINVAL;
 656
 657         ds->dst = dsa_tree_touch(m[0]);
 658         if (!ds->dst)
 659                 return -ENOMEM;
 660
 661         return 0;
 662 }
 663
 664 static int dsa_switch_parse_of(struct dsa_switch *ds, struct device_node *dn)
 665 {
 666         int err;
 667
 668         err = dsa_switch_parse_member_of(ds, dn);
 669         if (err)
 670                 return err;
 671
 672         return dsa_switch_parse_ports_of(ds, dn);
 673 }
 674
 675 static int dsa_port_parse(struct dsa_port *dp, const char *name,
 676                           struct device *dev)
 677 {
 678         if (!strcmp(name, "cpu")) {
 679                 struct net_device *master;
 680
 681                 master = dsa_dev_to_net_device(dev);
 682                 if (!master)
 683                         return -EPROBE_DEFER;
 684
 685                 dev_put(master);
 686
 687                 return dsa_port_parse_cpu(dp, master);
 688         }
 689
 690         if (!strcmp(name, "dsa"))
 691                 return dsa_port_parse_dsa(dp);
 692
 693         return dsa_port_parse_user(dp, name);
 694 }
 695
 696 static int dsa_switch_parse_ports(struct dsa_switch *ds,
 697                                   struct dsa_chip_data *cd)
 698 {
 699         bool valid_name_found = false;
 700         struct dsa_port *dp;
 701         struct device *dev;
 702         const char *name;
 703         unsigned int i;
 704         int err;
 705
 706         for (i = 0; i < DSA_MAX_PORTS; i++) {
 707                 name = cd->port_names[i];
 708                 dev = cd->netdev[i];
 709                 dp = &ds->ports[i];
 710
 711                 if (!name)
 712                         continue;
 713
 714                 err = dsa_port_parse(dp, name, dev);
 715                 if (err)
 716                         return err;
 717
 718                 valid_name_found = true;
 719         }
 720
 721         if (!valid_name_found && i == DSA_MAX_PORTS)
 722                 return -EINVAL;
 723
 724         return 0;
 725 }
 726
 727 static int dsa_switch_parse(struct dsa_switch *ds, struct dsa_chip_data *cd)
 728 {
 729         ds->cd = cd;
 730
 731         /* We don't support interconnected switches nor multiple trees via
 732          * platform data, so this is the unique switch of the tree.
 733          */
 734         ds->index = 0;
 735         ds->dst = dsa_tree_touch(0);
 736         if (!ds->dst)
 737                 return -ENOMEM;
 738
 739         return dsa_switch_parse_ports(ds, cd);
 740 }
 741
 742 static int dsa_switch_add(struct dsa_switch *ds)
 743 {
 744         struct dsa_switch_tree *dst = ds->dst;
 745
 746         return dsa_tree_add_switch(dst, ds);
 747 }
 748
 749 static int dsa_switch_probe(struct dsa_switch *ds)
 750 {
 751         struct dsa_chip_data *pdata = ds->dev->platform_data;
 752         struct device_node *np = ds->dev->of_node;
 753         int err;
 754
 755         if (np)
 756                 err = dsa_switch_parse_of(ds, np);
 757         else if (pdata)
 758                 err = dsa_switch_parse(ds, pdata);
 759         else
 760                 err = -ENODEV;
 761
 762         if (err)
 763                 return err;
 764
 765         return dsa_switch_add(ds);
 766 }
 767
 768 struct dsa_switch *dsa_switch_alloc(struct device *dev, size_t n)
 769 {
 770         size_t size = sizeof(struct dsa_switch) + n * sizeof(struct dsa_port);
 771         struct dsa_switch *ds;
 772         int i;
 773
 774         ds = devm_kzalloc(dev, size, GFP_KERNEL);
 775         if (!ds)
 776                 return NULL;
 777
 778         /* We avoid allocating memory outside dsa_switch
 779          * if it is not needed.
 780          */
 781         if (n <= sizeof(ds->_bitmap) * 8) {
 782                 ds->bitmap = &ds->_bitmap;
 783         } else {
 784                 ds->bitmap = devm_kcalloc(dev,
 785                                           BITS_TO_LONGS(n),
 786                                           sizeof(unsigned long),
 787                                           GFP_KERNEL);
 788                 if (unlikely(!ds->bitmap))
 789                         return NULL;
 790         }
 791
 792         ds->dev = dev;
 793         ds->num_ports = n;
 794
 795         for (i = 0; i < ds->num_ports; ++i) {
 796                 ds->ports[i].index = i;
 797                 ds->ports[i].ds = ds;
 798         }
 799
 800         return ds;
 801 }
 802 EXPORT_SYMBOL_GPL(dsa_switch_alloc);
 803
 804 int dsa_register_switch(struct dsa_switch *ds)
 805 {
 806         int err;
 807
 808         mutex_lock(&dsa2_mutex);
 809         err = dsa_switch_probe(ds);
 810         dsa_tree_put(ds->dst);
 811         mutex_unlock(&dsa2_mutex);
 812
 813         return err;
 814 }
 815 EXPORT_SYMBOL_GPL(dsa_register_switch);
 816
 817 static void dsa_switch_remove(struct dsa_switch *ds)
 818 {
 819         struct dsa_switch_tree *dst = ds->dst;
 820         unsigned int index = ds->index;
 821
 822         dsa_tree_remove_switch(dst, index);
 823 }
 824
 825 void dsa_unregister_switch(struct dsa_switch *ds)
 826 {
 827         mutex_lock(&dsa2_mutex);
 828         dsa_switch_remove(ds);
 829         mutex_unlock(&dsa2_mutex);
 830 }
 831 EXPORT_SYMBOL_GPL(dsa_unregister_switch);