drivers/net/can/dev.c

   1 /*
   2  * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
   3  * Copyright (C) 2006 Andrey Volkov, Varma Electronics
   4  * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the version 2 of the GNU General Public License
   8  * as published by the Free Software Foundation
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/kernel.h>
  21 #include <linux/slab.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/if_arp.h>
  24 #include <linux/workqueue.h>
  25 #include <linux/can.h>
  26 #include <linux/can/dev.h>
  27 #include <linux/can/skb.h>
  28 #include <linux/can/netlink.h>
  29 #include <linux/can/led.h>
  30 #include <linux/of.h>
  31 #include <net/rtnetlink.h>
  32
  33 #define MOD_DESC "CAN device driver interface"
  34
  35 MODULE_DESCRIPTION(MOD_DESC);
  36 MODULE_LICENSE("GPL v2");
  37 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
  38
  39 /* CAN DLC to real data length conversion helpers */
  40
  41 static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
  42                              8, 12, 16, 20, 24, 32, 48, 64};
  43
  44 /* get data length from can_dlc with sanitized can_dlc */
  45 u8 can_dlc2len(u8 can_dlc)
  46 {
  47         return dlc2len[can_dlc & 0x0F];
  48 }
  49 EXPORT_SYMBOL_GPL(can_dlc2len);
  50
  51 static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,         /* 0 - 8 */
  52                              9, 9, 9, 9,                        /* 9 - 12 */
  53                              10, 10, 10, 10,                    /* 13 - 16 */
  54                              11, 11, 11, 11,                    /* 17 - 20 */
  55                              12, 12, 12, 12,                    /* 21 - 24 */
  56                              13, 13, 13, 13, 13, 13, 13, 13,    /* 25 - 32 */
  57                              14, 14, 14, 14, 14, 14, 14, 14,    /* 33 - 40 */
  58                              14, 14, 14, 14, 14, 14, 14, 14,    /* 41 - 48 */
  59                              15, 15, 15, 15, 15, 15, 15, 15,    /* 49 - 56 */
  60                              15, 15, 15, 15, 15, 15, 15, 15};   /* 57 - 64 */
  61
  62 /* map the sanitized data length to an appropriate data length code */
  63 u8 can_len2dlc(u8 len)
  64 {
  65         if (unlikely(len > 64))
  66                 return 0xF;
  67
  68         return len2dlc[len];
  69 }
  70 EXPORT_SYMBOL_GPL(can_len2dlc);
  71
  72 #ifdef CONFIG_CAN_CALC_BITTIMING
  73 #define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
  74 #define CAN_CALC_SYNC_SEG 1
  75
  76 /*
  77  * Bit-timing calculation derived from:
  78  *
  79  * Code based on LinCAN sources and H8S2638 project
  80  * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
  81  * Copyright 2005      Stanislav Marek
  82  * email: pisa@cmp.felk.cvut.cz
  83  *
  84  * Calculates proper bit-timing parameters for a specified bit-rate
  85  * and sample-point, which can then be used to set the bit-timing
  86  * registers of the CAN controller. You can find more information
  87  * in the header file linux/can/netlink.h.
  88  */
  89 static int can_update_sample_point(const struct can_bittiming_const *btc,
  90                           unsigned int sample_point_nominal, unsigned int tseg,
  91                           unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
  92                           unsigned int *sample_point_error_ptr)
  93 {
  94         unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
  95         unsigned int sample_point, best_sample_point = 0;
  96         unsigned int tseg1, tseg2;
  97         int i;
  98
  99         for (i = 0; i <= 1; i++) {
 100                 tseg2 = tseg + CAN_CALC_SYNC_SEG - (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) / 1000 - i;
 101                 tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
 102                 tseg1 = tseg - tseg2;
 103                 if (tseg1 > btc->tseg1_max) {
 104                         tseg1 = btc->tseg1_max;
 105                         tseg2 = tseg - tseg1;
 106                 }
 107
 108                 sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) / (tseg + CAN_CALC_SYNC_SEG);
 109                 sample_point_error = abs(sample_point_nominal - sample_point);
 110
 111                 if ((sample_point <= sample_point_nominal) && (sample_point_error < best_sample_point_error)) {
 112                         best_sample_point = sample_point;
 113                         best_sample_point_error = sample_point_error;
 114                         *tseg1_ptr = tseg1;
 115                         *tseg2_ptr = tseg2;
 116                 }
 117         }
 118
 119         if (sample_point_error_ptr)
 120                 *sample_point_error_ptr = best_sample_point_error;
 121
 122         return best_sample_point;
 123 }
 124
 125 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 126                               const struct can_bittiming_const *btc)
 127 {
 128         struct can_priv *priv = netdev_priv(dev);
 129         unsigned int bitrate;                   /* current bitrate */
 130         unsigned int bitrate_error;             /* difference between current and nominal value */
 131         unsigned int best_bitrate_error = UINT_MAX;
 132         unsigned int sample_point_error;        /* difference between current and nominal value */
 133         unsigned int best_sample_point_error = UINT_MAX;
 134         unsigned int sample_point_nominal;      /* nominal sample point */
 135         unsigned int best_tseg = 0;             /* current best value for tseg */
 136         unsigned int best_brp = 0;              /* current best value for brp */
 137         unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
 138         u64 v64;
 139
 140         /* Use CiA recommended sample points */
 141         if (bt->sample_point) {
 142                 sample_point_nominal = bt->sample_point;
 143         } else {
 144                 if (bt->bitrate > 800000)
 145                         sample_point_nominal = 750;
 146                 else if (bt->bitrate > 500000)
 147                         sample_point_nominal = 800;
 148                 else
 149                         sample_point_nominal = 875;
 150         }
 151
 152         /* tseg even = round down, odd = round up */
 153         for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
 154              tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
 155                 tsegall = CAN_CALC_SYNC_SEG + tseg / 2;
 156
 157                 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
 158                 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
 159
 160                 /* choose brp step which is possible in system */
 161                 brp = (brp / btc->brp_inc) * btc->brp_inc;
 162                 if ((brp < btc->brp_min) || (brp > btc->brp_max))
 163                         continue;
 164
 165                 bitrate = priv->clock.freq / (brp * tsegall);
 166                 bitrate_error = abs(bt->bitrate - bitrate);
 167
 168                 /* tseg brp biterror */
 169                 if (bitrate_error > best_bitrate_error)
 170                         continue;
 171
 172                 /* reset sample point error if we have a better bitrate */
 173                 if (bitrate_error < best_bitrate_error)
 174                         best_sample_point_error = UINT_MAX;
 175
 176                 can_update_sample_point(btc, sample_point_nominal, tseg / 2, &tseg1, &tseg2, &sample_point_error);
 177                 if (sample_point_error > best_sample_point_error)
 178                         continue;
 179
 180                 best_sample_point_error = sample_point_error;
 181                 best_bitrate_error = bitrate_error;
 182                 best_tseg = tseg / 2;
 183                 best_brp = brp;
 184
 185                 if (bitrate_error == 0 && sample_point_error == 0)
 186                         break;
 187         }
 188
 189         if (best_bitrate_error) {
 190                 /* Error in one-tenth of a percent */
 191                 v64 = (u64)best_bitrate_error * 1000;
 192                 do_div(v64, bt->bitrate);
 193                 bitrate_error = (u32)v64;
 194                 if (bitrate_error > CAN_CALC_MAX_ERROR) {
 195                         netdev_err(dev,
 196                                    "bitrate error %d.%d%% too high\n",
 197                                    bitrate_error / 10, bitrate_error % 10);
 198                         return -EDOM;
 199                 }
 200                 netdev_warn(dev, "bitrate error %d.%d%%\n",
 201                             bitrate_error / 10, bitrate_error % 10);
 202         }
 203
 204         /* real sample point */
 205         bt->sample_point = can_update_sample_point(btc, sample_point_nominal, best_tseg,
 206                                           &tseg1, &tseg2, NULL);
 207
 208         v64 = (u64)best_brp * 1000 * 1000 * 1000;
 209         do_div(v64, priv->clock.freq);
 210         bt->tq = (u32)v64;
 211         bt->prop_seg = tseg1 / 2;
 212         bt->phase_seg1 = tseg1 - bt->prop_seg;
 213         bt->phase_seg2 = tseg2;
 214
 215         /* check for sjw user settings */
 216         if (!bt->sjw || !btc->sjw_max) {
 217                 bt->sjw = 1;
 218         } else {
 219                 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
 220                 if (bt->sjw > btc->sjw_max)
 221                         bt->sjw = btc->sjw_max;
 222                 /* bt->sjw must not be higher than tseg2 */
 223                 if (tseg2 < bt->sjw)
 224                         bt->sjw = tseg2;
 225         }
 226
 227         bt->brp = best_brp;
 228
 229         /* real bitrate */
 230         bt->bitrate = priv->clock.freq / (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2));
 231
 232         return 0;
 233 }
 234 #else /* !CONFIG_CAN_CALC_BITTIMING */
 235 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 236                               const struct can_bittiming_const *btc)
 237 {
 238         netdev_err(dev, "bit-timing calculation not available\n");
 239         return -EINVAL;
 240 }
 241 #endif /* CONFIG_CAN_CALC_BITTIMING */
 242
 243 /*
 244  * Checks the validity of the specified bit-timing parameters prop_seg,
 245  * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
 246  * prescaler value brp. You can find more information in the header
 247  * file linux/can/netlink.h.
 248  */
 249 static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
 250                                const struct can_bittiming_const *btc)
 251 {
 252         struct can_priv *priv = netdev_priv(dev);
 253         int tseg1, alltseg;
 254         u64 brp64;
 255
 256         tseg1 = bt->prop_seg + bt->phase_seg1;
 257         if (!bt->sjw)
 258                 bt->sjw = 1;
 259         if (bt->sjw > btc->sjw_max ||
 260             tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
 261             bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
 262                 return -ERANGE;
 263
 264         brp64 = (u64)priv->clock.freq * (u64)bt->tq;
 265         if (btc->brp_inc > 1)
 266                 do_div(brp64, btc->brp_inc);
 267         brp64 += 500000000UL - 1;
 268         do_div(brp64, 1000000000UL); /* the practicable BRP */
 269         if (btc->brp_inc > 1)
 270                 brp64 *= btc->brp_inc;
 271         bt->brp = (u32)brp64;
 272
 273         if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
 274                 return -EINVAL;
 275
 276         alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
 277         bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
 278         bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
 279
 280         return 0;
 281 }
 282
 283 /* Checks the validity of predefined bitrate settings */
 284 static int can_validate_bitrate(struct net_device *dev, struct can_bittiming *bt,
 285                                 const u32 *bitrate_const,
 286                                 const unsigned int bitrate_const_cnt)
 287 {
 288         struct can_priv *priv = netdev_priv(dev);
 289         unsigned int i;
 290
 291         for (i = 0; i < bitrate_const_cnt; i++) {
 292                 if (bt->bitrate == bitrate_const[i])
 293                         break;
 294         }
 295
 296         if (i >= priv->bitrate_const_cnt)
 297                 return -EINVAL;
 298
 299         return 0;
 300 }
 301
 302 static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
 303                              const struct can_bittiming_const *btc,
 304                              const u32 *bitrate_const,
 305                              const unsigned int bitrate_const_cnt)
 306 {
 307         int err;
 308
 309         /*
 310          * Depending on the given can_bittiming parameter structure the CAN
 311          * timing parameters are calculated based on the provided bitrate OR
 312          * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
 313          * provided directly which are then checked and fixed up.
 314          */
 315         if (!bt->tq && bt->bitrate && btc)
 316                 err = can_calc_bittiming(dev, bt, btc);
 317         else if (bt->tq && !bt->bitrate && btc)
 318                 err = can_fixup_bittiming(dev, bt, btc);
 319         else if (!bt->tq && bt->bitrate && bitrate_const)
 320                 err = can_validate_bitrate(dev, bt, bitrate_const,
 321                                            bitrate_const_cnt);
 322         else
 323                 err = -EINVAL;
 324
 325         return err;
 326 }
 327
 328 static void can_update_state_error_stats(struct net_device *dev,
 329                                          enum can_state new_state)
 330 {
 331         struct can_priv *priv = netdev_priv(dev);
 332
 333         if (new_state <= priv->state)
 334                 return;
 335
 336         switch (new_state) {
 337         case CAN_STATE_ERROR_WARNING:
 338                 priv->can_stats.error_warning++;
 339                 break;
 340         case CAN_STATE_ERROR_PASSIVE:
 341                 priv->can_stats.error_passive++;
 342                 break;
 343         case CAN_STATE_BUS_OFF:
 344                 priv->can_stats.bus_off++;
 345                 break;
 346         default:
 347                 break;
 348         }
 349 }
 350
 351 static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
 352 {
 353         switch (state) {
 354         case CAN_STATE_ERROR_ACTIVE:
 355                 return CAN_ERR_CRTL_ACTIVE;
 356         case CAN_STATE_ERROR_WARNING:
 357                 return CAN_ERR_CRTL_TX_WARNING;
 358         case CAN_STATE_ERROR_PASSIVE:
 359                 return CAN_ERR_CRTL_TX_PASSIVE;
 360         default:
 361                 return 0;
 362         }
 363 }
 364
 365 static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
 366 {
 367         switch (state) {
 368         case CAN_STATE_ERROR_ACTIVE:
 369                 return CAN_ERR_CRTL_ACTIVE;
 370         case CAN_STATE_ERROR_WARNING:
 371                 return CAN_ERR_CRTL_RX_WARNING;
 372         case CAN_STATE_ERROR_PASSIVE:
 373                 return CAN_ERR_CRTL_RX_PASSIVE;
 374         default:
 375                 return 0;
 376         }
 377 }
 378
 379 void can_change_state(struct net_device *dev, struct can_frame *cf,
 380                       enum can_state tx_state, enum can_state rx_state)
 381 {
 382         struct can_priv *priv = netdev_priv(dev);
 383         enum can_state new_state = max(tx_state, rx_state);
 384
 385         if (unlikely(new_state == priv->state)) {
 386                 netdev_warn(dev, "%s: oops, state did not change", __func__);
 387                 return;
 388         }
 389
 390         netdev_dbg(dev, "New error state: %d\n", new_state);
 391
 392         can_update_state_error_stats(dev, new_state);
 393         priv->state = new_state;
 394
 395         if (!cf)
 396                 return;
 397
 398         if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
 399                 cf->can_id |= CAN_ERR_BUSOFF;
 400                 return;
 401         }
 402
 403         cf->can_id |= CAN_ERR_CRTL;
 404         cf->data[1] |= tx_state >= rx_state ?
 405                        can_tx_state_to_frame(dev, tx_state) : 0;
 406         cf->data[1] |= tx_state <= rx_state ?
 407                        can_rx_state_to_frame(dev, rx_state) : 0;
 408 }
 409 EXPORT_SYMBOL_GPL(can_change_state);
 410
 411 /*
 412  * Local echo of CAN messages
 413  *
 414  * CAN network devices *should* support a local echo functionality
 415  * (see Documentation/networking/can.rst). To test the handling of CAN
 416  * interfaces that do not support the local echo both driver types are
 417  * implemented. In the case that the driver does not support the echo
 418  * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
 419  * to perform the echo as a fallback solution.
 420  */
 421 static void can_flush_echo_skb(struct net_device *dev)
 422 {
 423         struct can_priv *priv = netdev_priv(dev);
 424         struct net_device_stats *stats = &dev->stats;
 425         int i;
 426
 427         for (i = 0; i < priv->echo_skb_max; i++) {
 428                 if (priv->echo_skb[i]) {
 429                         kfree_skb(priv->echo_skb[i]);
 430                         priv->echo_skb[i] = NULL;
 431                         stats->tx_dropped++;
 432                         stats->tx_aborted_errors++;
 433                 }
 434         }
 435 }
 436
 437 /*
 438  * Put the skb on the stack to be looped backed locally lateron
 439  *
 440  * The function is typically called in the start_xmit function
 441  * of the device driver. The driver must protect access to
 442  * priv->echo_skb, if necessary.
 443  */
 444 void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 445                       unsigned int idx)
 446 {
 447         struct can_priv *priv = netdev_priv(dev);
 448
 449         BUG_ON(idx >= priv->echo_skb_max);
 450
 451         /* check flag whether this packet has to be looped back */
 452         if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
 453             (skb->protocol != htons(ETH_P_CAN) &&
 454              skb->protocol != htons(ETH_P_CANFD))) {
 455                 kfree_skb(skb);
 456                 return;
 457         }
 458
 459         if (!priv->echo_skb[idx]) {
 460
 461                 skb = can_create_echo_skb(skb);
 462                 if (!skb)
 463                         return;
 464
 465                 /* make settings for echo to reduce code in irq context */
 466                 skb->pkt_type = PACKET_BROADCAST;
 467                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 468                 skb->dev = dev;
 469
 470                 /* save this skb for tx interrupt echo handling */
 471                 priv->echo_skb[idx] = skb;
 472         } else {
 473                 /* locking problem with netif_stop_queue() ?? */
 474                 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
 475                 kfree_skb(skb);
 476         }
 477 }
 478 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 479
 480 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
 481 {
 482         struct can_priv *priv = netdev_priv(dev);
 483
 484         if (idx >= priv->echo_skb_max) {
 485                 netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
 486                            __func__, idx, priv->echo_skb_max);
 487                 return NULL;
 488         }
 489
 490         if (priv->echo_skb[idx]) {
 491                 /* Using "struct canfd_frame::len" for the frame
 492                  * length is supported on both CAN and CANFD frames.
 493                  */
 494                 struct sk_buff *skb = priv->echo_skb[idx];
 495                 struct canfd_frame *cf = (struct canfd_frame *)skb->data;
 496                 u8 len = cf->len;
 497
 498                 *len_ptr = len;
 499                 priv->echo_skb[idx] = NULL;
 500
 501                 return skb;
 502         }
 503
 504         return NULL;
 505 }
 506
 507 /*
 508  * Get the skb from the stack and loop it back locally
 509  *
 510  * The function is typically called when the TX done interrupt
 511  * is handled in the device driver. The driver must protect
 512  * access to priv->echo_skb, if necessary.
 513  */
 514 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 515 {
 516         struct sk_buff *skb;
 517         u8 len;
 518
 519         skb = __can_get_echo_skb(dev, idx, &len);
 520         if (!skb)
 521                 return 0;
 522
 523         netif_rx(skb);
 524
 525         return len;
 526 }
 527 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 528
 529 /*
 530   * Remove the skb from the stack and free it.
 531   *
 532   * The function is typically called when TX failed.
 533   */
 534 void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 535 {
 536         struct can_priv *priv = netdev_priv(dev);
 537
 538         BUG_ON(idx >= priv->echo_skb_max);
 539
 540         if (priv->echo_skb[idx]) {
 541                 dev_kfree_skb_any(priv->echo_skb[idx]);
 542                 priv->echo_skb[idx] = NULL;
 543         }
 544 }
 545 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 546
 547 /*
 548  * CAN device restart for bus-off recovery
 549  */
 550 static void can_restart(struct net_device *dev)
 551 {
 552         struct can_priv *priv = netdev_priv(dev);
 553         struct net_device_stats *stats = &dev->stats;
 554         struct sk_buff *skb;
 555         struct can_frame *cf;
 556         int err;
 557
 558         BUG_ON(netif_carrier_ok(dev));
 559
 560         /*
 561          * No synchronization needed because the device is bus-off and
 562          * no messages can come in or go out.
 563          */
 564         can_flush_echo_skb(dev);
 565
 566         /* send restart message upstream */
 567         skb = alloc_can_err_skb(dev, &cf);
 568         if (skb == NULL) {
 569                 err = -ENOMEM;
 570                 goto restart;
 571         }
 572         cf->can_id |= CAN_ERR_RESTARTED;
 573
 574         netif_rx(skb);
 575
 576         stats->rx_packets++;
 577         stats->rx_bytes += cf->can_dlc;
 578
 579 restart:
 580         netdev_dbg(dev, "restarted\n");
 581         priv->can_stats.restarts++;
 582
 583         /* Now restart the device */
 584         err = priv->do_set_mode(dev, CAN_MODE_START);
 585
 586         netif_carrier_on(dev);
 587         if (err)
 588                 netdev_err(dev, "Error %d during restart", err);
 589 }
 590
 591 static void can_restart_work(struct work_struct *work)
 592 {
 593         struct delayed_work *dwork = to_delayed_work(work);
 594         struct can_priv *priv = container_of(dwork, struct can_priv, restart_work);
 595
 596         can_restart(priv->dev);
 597 }
 598
 599 int can_restart_now(struct net_device *dev)
 600 {
 601         struct can_priv *priv = netdev_priv(dev);
 602
 603         /*
 604          * A manual restart is only permitted if automatic restart is
 605          * disabled and the device is in the bus-off state
 606          */
 607         if (priv->restart_ms)
 608                 return -EINVAL;
 609         if (priv->state != CAN_STATE_BUS_OFF)
 610                 return -EBUSY;
 611
 612         cancel_delayed_work_sync(&priv->restart_work);
 613         can_restart(dev);
 614
 615         return 0;
 616 }
 617
 618 /*
 619  * CAN bus-off
 620  *
 621  * This functions should be called when the device goes bus-off to
 622  * tell the netif layer that no more packets can be sent or received.
 623  * If enabled, a timer is started to trigger bus-off recovery.
 624  */
 625 void can_bus_off(struct net_device *dev)
 626 {
 627         struct can_priv *priv = netdev_priv(dev);
 628
 629         netdev_info(dev, "bus-off\n");
 630
 631         netif_carrier_off(dev);
 632
 633         if (priv->restart_ms)
 634                 schedule_delayed_work(&priv->restart_work,
 635                                       msecs_to_jiffies(priv->restart_ms));
 636 }
 637 EXPORT_SYMBOL_GPL(can_bus_off);
 638
 639 static void can_setup(struct net_device *dev)
 640 {
 641         dev->type = ARPHRD_CAN;
 642         dev->mtu = CAN_MTU;
 643         dev->hard_header_len = 0;
 644         dev->addr_len = 0;
 645         dev->tx_queue_len = 10;
 646
 647         /* New-style flags. */
 648         dev->flags = IFF_NOARP;
 649         dev->features = NETIF_F_HW_CSUM;
 650 }
 651
 652 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 653 {
 654         struct sk_buff *skb;
 655
 656         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 657                                sizeof(struct can_frame));
 658         if (unlikely(!skb))
 659                 return NULL;
 660
 661         skb->protocol = htons(ETH_P_CAN);
 662         skb->pkt_type = PACKET_BROADCAST;
 663         skb->ip_summed = CHECKSUM_UNNECESSARY;
 664
 665         skb_reset_mac_header(skb);
 666         skb_reset_network_header(skb);
 667         skb_reset_transport_header(skb);
 668
 669         can_skb_reserve(skb);
 670         can_skb_prv(skb)->ifindex = dev->ifindex;
 671         can_skb_prv(skb)->skbcnt = 0;
 672
 673         *cf = skb_put_zero(skb, sizeof(struct can_frame));
 674
 675         return skb;
 676 }
 677 EXPORT_SYMBOL_GPL(alloc_can_skb);
 678
 679 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 680                                 struct canfd_frame **cfd)
 681 {
 682         struct sk_buff *skb;
 683
 684         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 685                                sizeof(struct canfd_frame));
 686         if (unlikely(!skb))
 687                 return NULL;
 688
 689         skb->protocol = htons(ETH_P_CANFD);
 690         skb->pkt_type = PACKET_BROADCAST;
 691         skb->ip_summed = CHECKSUM_UNNECESSARY;
 692
 693         skb_reset_mac_header(skb);
 694         skb_reset_network_header(skb);
 695         skb_reset_transport_header(skb);
 696
 697         can_skb_reserve(skb);
 698         can_skb_prv(skb)->ifindex = dev->ifindex;
 699         can_skb_prv(skb)->skbcnt = 0;
 700
 701         *cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
 702
 703         return skb;
 704 }
 705 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 706
 707 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 708 {
 709         struct sk_buff *skb;
 710
 711         skb = alloc_can_skb(dev, cf);
 712         if (unlikely(!skb))
 713                 return NULL;
 714
 715         (*cf)->can_id = CAN_ERR_FLAG;
 716         (*cf)->can_dlc = CAN_ERR_DLC;
 717
 718         return skb;
 719 }
 720 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 721
 722 /*
 723  * Allocate and setup space for the CAN network device
 724  */
 725 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
 726                                     unsigned int txqs, unsigned int rxqs)
 727 {
 728         struct net_device *dev;
 729         struct can_priv *priv;
 730         int size;
 731
 732         if (echo_skb_max)
 733                 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
 734                         echo_skb_max * sizeof(struct sk_buff *);
 735         else
 736                 size = sizeof_priv;
 737
 738         dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup,
 739                                txqs, rxqs);
 740         if (!dev)
 741                 return NULL;
 742
 743         priv = netdev_priv(dev);
 744         priv->dev = dev;
 745
 746         if (echo_skb_max) {
 747                 priv->echo_skb_max = echo_skb_max;
 748                 priv->echo_skb = (void *)priv +
 749                         ALIGN(sizeof_priv, sizeof(struct sk_buff *));
 750         }
 751
 752         priv->state = CAN_STATE_STOPPED;
 753
 754         INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
 755
 756         return dev;
 757 }
 758 EXPORT_SYMBOL_GPL(alloc_candev_mqs);
 759
 760 /*
 761  * Free space of the CAN network device
 762  */
 763 void free_candev(struct net_device *dev)
 764 {
 765         free_netdev(dev);
 766 }
 767 EXPORT_SYMBOL_GPL(free_candev);
 768
 769 /*
 770  * changing MTU and control mode for CAN/CANFD devices
 771  */
 772 int can_change_mtu(struct net_device *dev, int new_mtu)
 773 {
 774         struct can_priv *priv = netdev_priv(dev);
 775
 776         /* Do not allow changing the MTU while running */
 777         if (dev->flags & IFF_UP)
 778                 return -EBUSY;
 779
 780         /* allow change of MTU according to the CANFD ability of the device */
 781         switch (new_mtu) {
 782         case CAN_MTU:
 783                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 784                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 785                         return -EINVAL;
 786
 787                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 788                 break;
 789
 790         case CANFD_MTU:
 791                 /* check for potential CANFD ability */
 792                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 793                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 794                         return -EINVAL;
 795
 796                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 797                 break;
 798
 799         default:
 800                 return -EINVAL;
 801         }
 802
 803         dev->mtu = new_mtu;
 804         return 0;
 805 }
 806 EXPORT_SYMBOL_GPL(can_change_mtu);
 807
 808 /*
 809  * Common open function when the device gets opened.
 810  *
 811  * This function should be called in the open function of the device
 812  * driver.
 813  */
 814 int open_candev(struct net_device *dev)
 815 {
 816         struct can_priv *priv = netdev_priv(dev);
 817
 818         if (!priv->bittiming.bitrate) {
 819                 netdev_err(dev, "bit-timing not yet defined\n");
 820                 return -EINVAL;
 821         }
 822
 823         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 824         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 825             (!priv->data_bittiming.bitrate ||
 826              (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
 827                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 828                 return -EINVAL;
 829         }
 830
 831         /* Switch carrier on if device was stopped while in bus-off state */
 832         if (!netif_carrier_ok(dev))
 833                 netif_carrier_on(dev);
 834
 835         return 0;
 836 }
 837 EXPORT_SYMBOL_GPL(open_candev);
 838
 839 #ifdef CONFIG_OF
 840 /* Common function that can be used to understand the limitation of
 841  * a transceiver when it provides no means to determine these limitations
 842  * at runtime.
 843  */
 844 void of_can_transceiver(struct net_device *dev)
 845 {
 846         struct device_node *dn;
 847         struct can_priv *priv = netdev_priv(dev);
 848         struct device_node *np = dev->dev.parent->of_node;
 849         int ret;
 850
 851         dn = of_get_child_by_name(np, "can-transceiver");
 852         if (!dn)
 853                 return;
 854
 855         ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max);
 856         if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
 857                 netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
 858 }
 859 EXPORT_SYMBOL_GPL(of_can_transceiver);
 860 #endif
 861
 862 /*
 863  * Common close function for cleanup before the device gets closed.
 864  *
 865  * This function should be called in the close function of the device
 866  * driver.
 867  */
 868 void close_candev(struct net_device *dev)
 869 {
 870         struct can_priv *priv = netdev_priv(dev);
 871
 872         cancel_delayed_work_sync(&priv->restart_work);
 873         can_flush_echo_skb(dev);
 874 }
 875 EXPORT_SYMBOL_GPL(close_candev);
 876
 877 /*
 878  * CAN netlink interface
 879  */
 880 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 881         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 882         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 883         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 884         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 885         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 886         [IFLA_CAN_BITTIMING_CONST]
 887                                 = { .len = sizeof(struct can_bittiming_const) },
 888         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 889         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 890         [IFLA_CAN_DATA_BITTIMING]
 891                                 = { .len = sizeof(struct can_bittiming) },
 892         [IFLA_CAN_DATA_BITTIMING_CONST]
 893                                 = { .len = sizeof(struct can_bittiming_const) },
 894 };
 895
 896 static int can_validate(struct nlattr *tb[], struct nlattr *data[],
 897                         struct netlink_ext_ack *extack)
 898 {
 899         bool is_can_fd = false;
 900
 901         /* Make sure that valid CAN FD configurations always consist of
 902          * - nominal/arbitration bittiming
 903          * - data bittiming
 904          * - control mode with CAN_CTRLMODE_FD set
 905          */
 906
 907         if (!data)
 908                 return 0;
 909
 910         if (data[IFLA_CAN_CTRLMODE]) {
 911                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 912
 913                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 914         }
 915
 916         if (is_can_fd) {
 917                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 918                         return -EOPNOTSUPP;
 919         }
 920
 921         if (data[IFLA_CAN_DATA_BITTIMING]) {
 922                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 923                         return -EOPNOTSUPP;
 924         }
 925
 926         return 0;
 927 }
 928
 929 static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 930                           struct nlattr *data[],
 931                           struct netlink_ext_ack *extack)
 932 {
 933         struct can_priv *priv = netdev_priv(dev);
 934         int err;
 935
 936         /* We need synchronization with dev->stop() */
 937         ASSERT_RTNL();
 938
 939         if (data[IFLA_CAN_BITTIMING]) {
 940                 struct can_bittiming bt;
 941
 942                 /* Do not allow changing bittiming while running */
 943                 if (dev->flags & IFF_UP)
 944                         return -EBUSY;
 945
 946                 /* Calculate bittiming parameters based on
 947                  * bittiming_const if set, otherwise pass bitrate
 948                  * directly via do_set_bitrate(). Bail out if neither
 949                  * is given.
 950                  */
 951                 if (!priv->bittiming_const && !priv->do_set_bittiming)
 952                         return -EOPNOTSUPP;
 953
 954                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 955                 err = can_get_bittiming(dev, &bt,
 956                                         priv->bittiming_const,
 957                                         priv->bitrate_const,
 958                                         priv->bitrate_const_cnt);
 959                 if (err)
 960                         return err;
 961
 962                 if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) {
 963                         netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n",
 964                                    priv->bitrate_max);
 965                         return -EINVAL;
 966                 }
 967
 968                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 969
 970                 if (priv->do_set_bittiming) {
 971                         /* Finally, set the bit-timing registers */
 972                         err = priv->do_set_bittiming(dev);
 973                         if (err)
 974                                 return err;
 975                 }
 976         }
 977
 978         if (data[IFLA_CAN_CTRLMODE]) {
 979                 struct can_ctrlmode *cm;
 980                 u32 ctrlstatic;
 981                 u32 maskedflags;
 982
 983                 /* Do not allow changing controller mode while running */
 984                 if (dev->flags & IFF_UP)
 985                         return -EBUSY;
 986                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 987                 ctrlstatic = priv->ctrlmode_static;
 988                 maskedflags = cm->flags & cm->mask;
 989
 990                 /* check whether provided bits are allowed to be passed */
 991                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
 992                         return -EOPNOTSUPP;
 993
 994                 /* do not check for static fd-non-iso if 'fd' is disabled */
 995                 if (!(maskedflags & CAN_CTRLMODE_FD))
 996                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
 997
 998                 /* make sure static options are provided by configuration */
 999                 if ((maskedflags & ctrlstatic) != ctrlstatic)
1000                         return -EOPNOTSUPP;
1001
1002                 /* clear bits to be modified and copy the flag values */
1003                 priv->ctrlmode &= ~cm->mask;
1004                 priv->ctrlmode |= maskedflags;
1005
1006                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
1007                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
1008                         dev->mtu = CANFD_MTU;
1009                 else
1010                         dev->mtu = CAN_MTU;
1011         }
1012
1013         if (data[IFLA_CAN_RESTART_MS]) {
1014                 /* Do not allow changing restart delay while running */
1015                 if (dev->flags & IFF_UP)
1016                         return -EBUSY;
1017                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
1018         }
1019
1020         if (data[IFLA_CAN_RESTART]) {
1021                 /* Do not allow a restart while not running */
1022                 if (!(dev->flags & IFF_UP))
1023                         return -EINVAL;
1024                 err = can_restart_now(dev);
1025                 if (err)
1026                         return err;
1027         }
1028
1029         if (data[IFLA_CAN_DATA_BITTIMING]) {
1030                 struct can_bittiming dbt;
1031
1032                 /* Do not allow changing bittiming while running */
1033                 if (dev->flags & IFF_UP)
1034                         return -EBUSY;
1035
1036                 /* Calculate bittiming parameters based on
1037                  * data_bittiming_const if set, otherwise pass bitrate
1038                  * directly via do_set_bitrate(). Bail out if neither
1039                  * is given.
1040                  */
1041                 if (!priv->data_bittiming_const && !priv->do_set_data_bittiming)
1042                         return -EOPNOTSUPP;
1043
1044                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
1045                        sizeof(dbt));
1046                 err = can_get_bittiming(dev, &dbt,
1047                                         priv->data_bittiming_const,
1048                                         priv->data_bitrate_const,
1049                                         priv->data_bitrate_const_cnt);
1050                 if (err)
1051                         return err;
1052
1053                 if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
1054                         netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
1055                                    priv->bitrate_max);
1056                         return -EINVAL;
1057                 }
1058
1059                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
1060
1061                 if (priv->do_set_data_bittiming) {
1062                         /* Finally, set the bit-timing registers */
1063                         err = priv->do_set_data_bittiming(dev);
1064                         if (err)
1065                                 return err;
1066                 }
1067         }
1068
1069         if (data[IFLA_CAN_TERMINATION]) {
1070                 const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]);
1071                 const unsigned int num_term = priv->termination_const_cnt;
1072                 unsigned int i;
1073
1074                 if (!priv->do_set_termination)
1075                         return -EOPNOTSUPP;
1076
1077                 /* check whether given value is supported by the interface */
1078                 for (i = 0; i < num_term; i++) {
1079                         if (termval == priv->termination_const[i])
1080                                 break;
1081                 }
1082                 if (i >= num_term)
1083                         return -EINVAL;
1084
1085                 /* Finally, set the termination value */
1086                 err = priv->do_set_termination(dev, termval);
1087                 if (err)
1088                         return err;
1089
1090                 priv->termination = termval;
1091         }
1092
1093         return 0;
1094 }
1095
1096 static size_t can_get_size(const struct net_device *dev)
1097 {
1098         struct can_priv *priv = netdev_priv(dev);
1099         size_t size = 0;
1100
1101         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
1102                 size += nla_total_size(sizeof(struct can_bittiming));
1103         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
1104                 size += nla_total_size(sizeof(struct can_bittiming_const));
1105         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
1106         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
1107         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
1108         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
1109         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
1110                 size += nla_total_size(sizeof(struct can_berr_counter));
1111         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
1112                 size += nla_total_size(sizeof(struct can_bittiming));
1113         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
1114                 size += nla_total_size(sizeof(struct can_bittiming_const));
1115         if (priv->termination_const) {
1116                 size += nla_total_size(sizeof(priv->termination));              /* IFLA_CAN_TERMINATION */
1117                 size += nla_total_size(sizeof(*priv->termination_const) *       /* IFLA_CAN_TERMINATION_CONST */
1118                                        priv->termination_const_cnt);
1119         }
1120         if (priv->bitrate_const)                                /* IFLA_CAN_BITRATE_CONST */
1121                 size += nla_total_size(sizeof(*priv->bitrate_const) *
1122                                        priv->bitrate_const_cnt);
1123         if (priv->data_bitrate_const)                           /* IFLA_CAN_DATA_BITRATE_CONST */
1124                 size += nla_total_size(sizeof(*priv->data_bitrate_const) *
1125                                        priv->data_bitrate_const_cnt);
1126         size += sizeof(priv->bitrate_max);                      /* IFLA_CAN_BITRATE_MAX */
1127
1128         return size;
1129 }
1130
1131 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
1132 {
1133         struct can_priv *priv = netdev_priv(dev);
1134         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
1135         struct can_berr_counter bec;
1136         enum can_state state = priv->state;
1137
1138         if (priv->do_get_state)
1139                 priv->do_get_state(dev, &state);
1140
1141         if ((priv->bittiming.bitrate &&
1142              nla_put(skb, IFLA_CAN_BITTIMING,
1143                      sizeof(priv->bittiming), &priv->bittiming)) ||
1144
1145             (priv->bittiming_const &&
1146              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1147                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1148
1149             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1150             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1151             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1152             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1153
1154             (priv->do_get_berr_counter &&
1155              !priv->do_get_berr_counter(dev, &bec) &&
1156              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1157
1158             (priv->data_bittiming.bitrate &&
1159              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1160                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1161
1162             (priv->data_bittiming_const &&
1163              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1164                      sizeof(*priv->data_bittiming_const),
1165                      priv->data_bittiming_const)) ||
1166
1167             (priv->termination_const &&
1168              (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||
1169               nla_put(skb, IFLA_CAN_TERMINATION_CONST,
1170                       sizeof(*priv->termination_const) *
1171                       priv->termination_const_cnt,
1172                       priv->termination_const))) ||
1173
1174             (priv->bitrate_const &&
1175              nla_put(skb, IFLA_CAN_BITRATE_CONST,
1176                      sizeof(*priv->bitrate_const) *
1177                      priv->bitrate_const_cnt,
1178                      priv->bitrate_const)) ||
1179
1180             (priv->data_bitrate_const &&
1181              nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
1182                      sizeof(*priv->data_bitrate_const) *
1183                      priv->data_bitrate_const_cnt,
1184                      priv->data_bitrate_const)) ||
1185
1186             (nla_put(skb, IFLA_CAN_BITRATE_MAX,
1187                      sizeof(priv->bitrate_max),
1188                      &priv->bitrate_max))
1189             )
1190
1191                 return -EMSGSIZE;
1192
1193         return 0;
1194 }
1195
1196 static size_t can_get_xstats_size(const struct net_device *dev)
1197 {
1198         return sizeof(struct can_device_stats);
1199 }
1200
1201 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1202 {
1203         struct can_priv *priv = netdev_priv(dev);
1204
1205         if (nla_put(skb, IFLA_INFO_XSTATS,
1206                     sizeof(priv->can_stats), &priv->can_stats))
1207                 goto nla_put_failure;
1208         return 0;
1209
1210 nla_put_failure:
1211         return -EMSGSIZE;
1212 }
1213
1214 static int can_newlink(struct net *src_net, struct net_device *dev,
1215                        struct nlattr *tb[], struct nlattr *data[],
1216                        struct netlink_ext_ack *extack)
1217 {
1218         return -EOPNOTSUPP;
1219 }
1220
1221 static void can_dellink(struct net_device *dev, struct list_head *head)
1222 {
1223         return;
1224 }
1225
1226 static struct rtnl_link_ops can_link_ops __read_mostly = {
1227         .kind           = "can",
1228         .maxtype        = IFLA_CAN_MAX,
1229         .policy         = can_policy,
1230         .setup          = can_setup,
1231         .validate       = can_validate,
1232         .newlink        = can_newlink,
1233         .changelink     = can_changelink,
1234         .dellink        = can_dellink,
1235         .get_size       = can_get_size,
1236         .fill_info      = can_fill_info,
1237         .get_xstats_size = can_get_xstats_size,
1238         .fill_xstats    = can_fill_xstats,
1239 };
1240
1241 /*
1242  * Register the CAN network device
1243  */
1244 int register_candev(struct net_device *dev)
1245 {
1246         struct can_priv *priv = netdev_priv(dev);
1247
1248         /* Ensure termination_const, termination_const_cnt and
1249          * do_set_termination consistency. All must be either set or
1250          * unset.
1251          */
1252         if ((!priv->termination_const != !priv->termination_const_cnt) ||
1253             (!priv->termination_const != !priv->do_set_termination))
1254                 return -EINVAL;
1255
1256         if (!priv->bitrate_const != !priv->bitrate_const_cnt)
1257                 return -EINVAL;
1258
1259         if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
1260                 return -EINVAL;
1261
1262         dev->rtnl_link_ops = &can_link_ops;
1263         return register_netdev(dev);
1264 }
1265 EXPORT_SYMBOL_GPL(register_candev);
1266
1267 /*
1268  * Unregister the CAN network device
1269  */
1270 void unregister_candev(struct net_device *dev)
1271 {
1272         unregister_netdev(dev);
1273 }
1274 EXPORT_SYMBOL_GPL(unregister_candev);
1275
1276 /*
1277  * Test if a network device is a candev based device
1278  * and return the can_priv* if so.
1279  */
1280 struct can_priv *safe_candev_priv(struct net_device *dev)
1281 {
1282         if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1283                 return NULL;
1284
1285         return netdev_priv(dev);
1286 }
1287 EXPORT_SYMBOL_GPL(safe_candev_priv);
1288
1289 static __init int can_dev_init(void)
1290 {
1291         int err;
1292
1293         can_led_notifier_init();
1294
1295         err = rtnl_link_register(&can_link_ops);
1296         if (!err)
1297                 printk(KERN_INFO MOD_DESC "\n");
1298
1299         return err;
1300 }
1301 module_init(can_dev_init);
1302
1303 static __exit void can_dev_exit(void)
1304 {
1305         rtnl_link_unregister(&can_link_ops);
1306
1307         can_led_notifier_exit();
1308 }
1309 module_exit(can_dev_exit);
1310
1311 MODULE_ALIAS_RTNL_LINK("can");