drivers/net/can/dev.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   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
   7 #include <linux/module.h>
   8 #include <linux/kernel.h>
   9 #include <linux/slab.h>
  10 #include <linux/netdevice.h>
  11 #include <linux/if_arp.h>
  12 #include <linux/workqueue.h>
  13 #include <linux/can.h>
  14 #include <linux/can/can-ml.h>
  15 #include <linux/can/dev.h>
  16 #include <linux/can/skb.h>
  17 #include <linux/can/netlink.h>
  18 #include <linux/can/led.h>
  19 #include <linux/of.h>
  20 #include <net/rtnetlink.h>
  21
  22 #define MOD_DESC "CAN device driver interface"
  23
  24 MODULE_DESCRIPTION(MOD_DESC);
  25 MODULE_LICENSE("GPL v2");
  26 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
  27
  28 /* CAN DLC to real data length conversion helpers */
  29
  30 static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
  31                              8, 12, 16, 20, 24, 32, 48, 64};
  32
  33 /* get data length from can_dlc with sanitized can_dlc */
  34 u8 can_dlc2len(u8 can_dlc)
  35 {
  36         return dlc2len[can_dlc & 0x0F];
  37 }
  38 EXPORT_SYMBOL_GPL(can_dlc2len);
  39
  40 static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,         /* 0 - 8 */
  41                              9, 9, 9, 9,                        /* 9 - 12 */
  42                              10, 10, 10, 10,                    /* 13 - 16 */
  43                              11, 11, 11, 11,                    /* 17 - 20 */
  44                              12, 12, 12, 12,                    /* 21 - 24 */
  45                              13, 13, 13, 13, 13, 13, 13, 13,    /* 25 - 32 */
  46                              14, 14, 14, 14, 14, 14, 14, 14,    /* 33 - 40 */
  47                              14, 14, 14, 14, 14, 14, 14, 14,    /* 41 - 48 */
  48                              15, 15, 15, 15, 15, 15, 15, 15,    /* 49 - 56 */
  49                              15, 15, 15, 15, 15, 15, 15, 15};   /* 57 - 64 */
  50
  51 /* map the sanitized data length to an appropriate data length code */
  52 u8 can_len2dlc(u8 len)
  53 {
  54         if (unlikely(len > 64))
  55                 return 0xF;
  56
  57         return len2dlc[len];
  58 }
  59 EXPORT_SYMBOL_GPL(can_len2dlc);
  60
  61 #ifdef CONFIG_CAN_CALC_BITTIMING
  62 #define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
  63 #define CAN_CALC_SYNC_SEG 1
  64
  65 /* Bit-timing calculation derived from:
  66  *
  67  * Code based on LinCAN sources and H8S2638 project
  68  * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
  69  * Copyright 2005      Stanislav Marek
  70  * email: pisa@cmp.felk.cvut.cz
  71  *
  72  * Calculates proper bit-timing parameters for a specified bit-rate
  73  * and sample-point, which can then be used to set the bit-timing
  74  * registers of the CAN controller. You can find more information
  75  * in the header file linux/can/netlink.h.
  76  */
  77 static int
  78 can_update_sample_point(const struct can_bittiming_const *btc,
  79                         unsigned int sample_point_nominal, unsigned int tseg,
  80                         unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
  81                         unsigned int *sample_point_error_ptr)
  82 {
  83         unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
  84         unsigned int sample_point, best_sample_point = 0;
  85         unsigned int tseg1, tseg2;
  86         int i;
  87
  88         for (i = 0; i <= 1; i++) {
  89                 tseg2 = tseg + CAN_CALC_SYNC_SEG -
  90                         (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) /
  91                         1000 - i;
  92                 tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
  93                 tseg1 = tseg - tseg2;
  94                 if (tseg1 > btc->tseg1_max) {
  95                         tseg1 = btc->tseg1_max;
  96                         tseg2 = tseg - tseg1;
  97                 }
  98
  99                 sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) /
 100                         (tseg + CAN_CALC_SYNC_SEG);
 101                 sample_point_error = abs(sample_point_nominal - sample_point);
 102
 103                 if (sample_point <= sample_point_nominal &&
 104                     sample_point_error < best_sample_point_error) {
 105                         best_sample_point = sample_point;
 106                         best_sample_point_error = sample_point_error;
 107                         *tseg1_ptr = tseg1;
 108                         *tseg2_ptr = tseg2;
 109                 }
 110         }
 111
 112         if (sample_point_error_ptr)
 113                 *sample_point_error_ptr = best_sample_point_error;
 114
 115         return best_sample_point;
 116 }
 117
 118 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 119                               const struct can_bittiming_const *btc)
 120 {
 121         struct can_priv *priv = netdev_priv(dev);
 122         unsigned int bitrate;                   /* current bitrate */
 123         unsigned int bitrate_error;             /* difference between current and nominal value */
 124         unsigned int best_bitrate_error = UINT_MAX;
 125         unsigned int sample_point_error;        /* difference between current and nominal value */
 126         unsigned int best_sample_point_error = UINT_MAX;
 127         unsigned int sample_point_nominal;      /* nominal sample point */
 128         unsigned int best_tseg = 0;             /* current best value for tseg */
 129         unsigned int best_brp = 0;              /* current best value for brp */
 130         unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
 131         u64 v64;
 132
 133         /* Use CiA recommended sample points */
 134         if (bt->sample_point) {
 135                 sample_point_nominal = bt->sample_point;
 136         } else {
 137                 if (bt->bitrate > 800000)
 138                         sample_point_nominal = 750;
 139                 else if (bt->bitrate > 500000)
 140                         sample_point_nominal = 800;
 141                 else
 142                         sample_point_nominal = 875;
 143         }
 144
 145         /* tseg even = round down, odd = round up */
 146         for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
 147              tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
 148                 tsegall = CAN_CALC_SYNC_SEG + tseg / 2;
 149
 150                 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
 151                 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
 152
 153                 /* choose brp step which is possible in system */
 154                 brp = (brp / btc->brp_inc) * btc->brp_inc;
 155                 if (brp < btc->brp_min || brp > btc->brp_max)
 156                         continue;
 157
 158                 bitrate = priv->clock.freq / (brp * tsegall);
 159                 bitrate_error = abs(bt->bitrate - bitrate);
 160
 161                 /* tseg brp biterror */
 162                 if (bitrate_error > best_bitrate_error)
 163                         continue;
 164
 165                 /* reset sample point error if we have a better bitrate */
 166                 if (bitrate_error < best_bitrate_error)
 167                         best_sample_point_error = UINT_MAX;
 168
 169                 can_update_sample_point(btc, sample_point_nominal, tseg / 2,
 170                                         &tseg1, &tseg2, &sample_point_error);
 171                 if (sample_point_error > best_sample_point_error)
 172                         continue;
 173
 174                 best_sample_point_error = sample_point_error;
 175                 best_bitrate_error = bitrate_error;
 176                 best_tseg = tseg / 2;
 177                 best_brp = brp;
 178
 179                 if (bitrate_error == 0 && sample_point_error == 0)
 180                         break;
 181         }
 182
 183         if (best_bitrate_error) {
 184                 /* Error in one-tenth of a percent */
 185                 v64 = (u64)best_bitrate_error * 1000;
 186                 do_div(v64, bt->bitrate);
 187                 bitrate_error = (u32)v64;
 188                 if (bitrate_error > CAN_CALC_MAX_ERROR) {
 189                         netdev_err(dev,
 190                                    "bitrate error %d.%d%% too high\n",
 191                                    bitrate_error / 10, bitrate_error % 10);
 192                         return -EDOM;
 193                 }
 194                 netdev_warn(dev, "bitrate error %d.%d%%\n",
 195                             bitrate_error / 10, bitrate_error % 10);
 196         }
 197
 198         /* real sample point */
 199         bt->sample_point = can_update_sample_point(btc, sample_point_nominal,
 200                                                    best_tseg, &tseg1, &tseg2,
 201                                                    NULL);
 202
 203         v64 = (u64)best_brp * 1000 * 1000 * 1000;
 204         do_div(v64, priv->clock.freq);
 205         bt->tq = (u32)v64;
 206         bt->prop_seg = tseg1 / 2;
 207         bt->phase_seg1 = tseg1 - bt->prop_seg;
 208         bt->phase_seg2 = tseg2;
 209
 210         /* check for sjw user settings */
 211         if (!bt->sjw || !btc->sjw_max) {
 212                 bt->sjw = 1;
 213         } else {
 214                 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
 215                 if (bt->sjw > btc->sjw_max)
 216                         bt->sjw = btc->sjw_max;
 217                 /* bt->sjw must not be higher than tseg2 */
 218                 if (tseg2 < bt->sjw)
 219                         bt->sjw = tseg2;
 220         }
 221
 222         bt->brp = best_brp;
 223
 224         /* real bitrate */
 225         bt->bitrate = priv->clock.freq /
 226                 (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2));
 227
 228         return 0;
 229 }
 230 #else /* !CONFIG_CAN_CALC_BITTIMING */
 231 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 232                               const struct can_bittiming_const *btc)
 233 {
 234         netdev_err(dev, "bit-timing calculation not available\n");
 235         return -EINVAL;
 236 }
 237 #endif /* CONFIG_CAN_CALC_BITTIMING */
 238
 239 /* Checks the validity of the specified bit-timing parameters prop_seg,
 240  * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
 241  * prescaler value brp. You can find more information in the header
 242  * file linux/can/netlink.h.
 243  */
 244 static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
 245                                const struct can_bittiming_const *btc)
 246 {
 247         struct can_priv *priv = netdev_priv(dev);
 248         int tseg1, alltseg;
 249         u64 brp64;
 250
 251         tseg1 = bt->prop_seg + bt->phase_seg1;
 252         if (!bt->sjw)
 253                 bt->sjw = 1;
 254         if (bt->sjw > btc->sjw_max ||
 255             tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
 256             bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
 257                 return -ERANGE;
 258
 259         brp64 = (u64)priv->clock.freq * (u64)bt->tq;
 260         if (btc->brp_inc > 1)
 261                 do_div(brp64, btc->brp_inc);
 262         brp64 += 500000000UL - 1;
 263         do_div(brp64, 1000000000UL); /* the practicable BRP */
 264         if (btc->brp_inc > 1)
 265                 brp64 *= btc->brp_inc;
 266         bt->brp = (u32)brp64;
 267
 268         if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
 269                 return -EINVAL;
 270
 271         alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
 272         bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
 273         bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
 274
 275         return 0;
 276 }
 277
 278 /* Checks the validity of predefined bitrate settings */
 279 static int
 280 can_validate_bitrate(struct net_device *dev, struct can_bittiming *bt,
 281                      const u32 *bitrate_const,
 282                      const unsigned int bitrate_const_cnt)
 283 {
 284         struct can_priv *priv = netdev_priv(dev);
 285         unsigned int i;
 286
 287         for (i = 0; i < bitrate_const_cnt; i++) {
 288                 if (bt->bitrate == bitrate_const[i])
 289                         break;
 290         }
 291
 292         if (i >= priv->bitrate_const_cnt)
 293                 return -EINVAL;
 294
 295         return 0;
 296 }
 297
 298 static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
 299                              const struct can_bittiming_const *btc,
 300                              const u32 *bitrate_const,
 301                              const unsigned int bitrate_const_cnt)
 302 {
 303         int err;
 304
 305         /* Depending on the given can_bittiming parameter structure the CAN
 306          * timing parameters are calculated based on the provided bitrate OR
 307          * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
 308          * provided directly which are then checked and fixed up.
 309          */
 310         if (!bt->tq && bt->bitrate && btc)
 311                 err = can_calc_bittiming(dev, bt, btc);
 312         else if (bt->tq && !bt->bitrate && btc)
 313                 err = can_fixup_bittiming(dev, bt, btc);
 314         else if (!bt->tq && bt->bitrate && bitrate_const)
 315                 err = can_validate_bitrate(dev, bt, bitrate_const,
 316                                            bitrate_const_cnt);
 317         else
 318                 err = -EINVAL;
 319
 320         return err;
 321 }
 322
 323 static void can_update_state_error_stats(struct net_device *dev,
 324                                          enum can_state new_state)
 325 {
 326         struct can_priv *priv = netdev_priv(dev);
 327
 328         if (new_state <= priv->state)
 329                 return;
 330
 331         switch (new_state) {
 332         case CAN_STATE_ERROR_WARNING:
 333                 priv->can_stats.error_warning++;
 334                 break;
 335         case CAN_STATE_ERROR_PASSIVE:
 336                 priv->can_stats.error_passive++;
 337                 break;
 338         case CAN_STATE_BUS_OFF:
 339                 priv->can_stats.bus_off++;
 340                 break;
 341         default:
 342                 break;
 343         }
 344 }
 345
 346 static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
 347 {
 348         switch (state) {
 349         case CAN_STATE_ERROR_ACTIVE:
 350                 return CAN_ERR_CRTL_ACTIVE;
 351         case CAN_STATE_ERROR_WARNING:
 352                 return CAN_ERR_CRTL_TX_WARNING;
 353         case CAN_STATE_ERROR_PASSIVE:
 354                 return CAN_ERR_CRTL_TX_PASSIVE;
 355         default:
 356                 return 0;
 357         }
 358 }
 359
 360 static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
 361 {
 362         switch (state) {
 363         case CAN_STATE_ERROR_ACTIVE:
 364                 return CAN_ERR_CRTL_ACTIVE;
 365         case CAN_STATE_ERROR_WARNING:
 366                 return CAN_ERR_CRTL_RX_WARNING;
 367         case CAN_STATE_ERROR_PASSIVE:
 368                 return CAN_ERR_CRTL_RX_PASSIVE;
 369         default:
 370                 return 0;
 371         }
 372 }
 373
 374 void can_change_state(struct net_device *dev, struct can_frame *cf,
 375                       enum can_state tx_state, enum can_state rx_state)
 376 {
 377         struct can_priv *priv = netdev_priv(dev);
 378         enum can_state new_state = max(tx_state, rx_state);
 379
 380         if (unlikely(new_state == priv->state)) {
 381                 netdev_warn(dev, "%s: oops, state did not change", __func__);
 382                 return;
 383         }
 384
 385         netdev_dbg(dev, "New error state: %d\n", new_state);
 386
 387         can_update_state_error_stats(dev, new_state);
 388         priv->state = new_state;
 389
 390         if (!cf)
 391                 return;
 392
 393         if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
 394                 cf->can_id |= CAN_ERR_BUSOFF;
 395                 return;
 396         }
 397
 398         cf->can_id |= CAN_ERR_CRTL;
 399         cf->data[1] |= tx_state >= rx_state ?
 400                        can_tx_state_to_frame(dev, tx_state) : 0;
 401         cf->data[1] |= tx_state <= rx_state ?
 402                        can_rx_state_to_frame(dev, rx_state) : 0;
 403 }
 404 EXPORT_SYMBOL_GPL(can_change_state);
 405
 406 /* Local echo of CAN messages
 407  *
 408  * CAN network devices *should* support a local echo functionality
 409  * (see Documentation/networking/can.rst). To test the handling of CAN
 410  * interfaces that do not support the local echo both driver types are
 411  * implemented. In the case that the driver does not support the echo
 412  * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
 413  * to perform the echo as a fallback solution.
 414  */
 415 static void can_flush_echo_skb(struct net_device *dev)
 416 {
 417         struct can_priv *priv = netdev_priv(dev);
 418         struct net_device_stats *stats = &dev->stats;
 419         int i;
 420
 421         for (i = 0; i < priv->echo_skb_max; i++) {
 422                 if (priv->echo_skb[i]) {
 423                         kfree_skb(priv->echo_skb[i]);
 424                         priv->echo_skb[i] = NULL;
 425                         stats->tx_dropped++;
 426                         stats->tx_aborted_errors++;
 427                 }
 428         }
 429 }
 430
 431 /* Put the skb on the stack to be looped backed locally lateron
 432  *
 433  * The function is typically called in the start_xmit function
 434  * of the device driver. The driver must protect access to
 435  * priv->echo_skb, if necessary.
 436  */
 437 void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 438                       unsigned int idx)
 439 {
 440         struct can_priv *priv = netdev_priv(dev);
 441
 442         BUG_ON(idx >= priv->echo_skb_max);
 443
 444         /* check flag whether this packet has to be looped back */
 445         if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
 446             (skb->protocol != htons(ETH_P_CAN) &&
 447              skb->protocol != htons(ETH_P_CANFD))) {
 448                 kfree_skb(skb);
 449                 return;
 450         }
 451
 452         if (!priv->echo_skb[idx]) {
 453                 skb = can_create_echo_skb(skb);
 454                 if (!skb)
 455                         return;
 456
 457                 /* make settings for echo to reduce code in irq context */
 458                 skb->pkt_type = PACKET_BROADCAST;
 459                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 460                 skb->dev = dev;
 461
 462                 /* save this skb for tx interrupt echo handling */
 463                 priv->echo_skb[idx] = skb;
 464         } else {
 465                 /* locking problem with netif_stop_queue() ?? */
 466                 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
 467                 kfree_skb(skb);
 468         }
 469 }
 470 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 471
 472 struct sk_buff *
 473 __can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
 474 {
 475         struct can_priv *priv = netdev_priv(dev);
 476
 477         if (idx >= priv->echo_skb_max) {
 478                 netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
 479                            __func__, idx, priv->echo_skb_max);
 480                 return NULL;
 481         }
 482
 483         if (priv->echo_skb[idx]) {
 484                 /* Using "struct canfd_frame::len" for the frame
 485                  * length is supported on both CAN and CANFD frames.
 486                  */
 487                 struct sk_buff *skb = priv->echo_skb[idx];
 488                 struct canfd_frame *cf = (struct canfd_frame *)skb->data;
 489                 u8 len = cf->len;
 490
 491                 *len_ptr = len;
 492                 priv->echo_skb[idx] = NULL;
 493
 494                 return skb;
 495         }
 496
 497         return NULL;
 498 }
 499
 500 /* Get the skb from the stack and loop it back locally
 501  *
 502  * The function is typically called when the TX done interrupt
 503  * is handled in the device driver. The driver must protect
 504  * access to priv->echo_skb, if necessary.
 505  */
 506 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 507 {
 508         struct sk_buff *skb;
 509         u8 len;
 510
 511         skb = __can_get_echo_skb(dev, idx, &len);
 512         if (!skb)
 513                 return 0;
 514
 515         netif_rx(skb);
 516
 517         return len;
 518 }
 519 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 520
 521 /* Remove the skb from the stack and free it.
 522  *
 523  * The function is typically called when TX failed.
 524  */
 525 void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 526 {
 527         struct can_priv *priv = netdev_priv(dev);
 528
 529         BUG_ON(idx >= priv->echo_skb_max);
 530
 531         if (priv->echo_skb[idx]) {
 532                 dev_kfree_skb_any(priv->echo_skb[idx]);
 533                 priv->echo_skb[idx] = NULL;
 534         }
 535 }
 536 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 537
 538 /* CAN device restart for bus-off recovery */
 539 static void can_restart(struct net_device *dev)
 540 {
 541         struct can_priv *priv = netdev_priv(dev);
 542         struct net_device_stats *stats = &dev->stats;
 543         struct sk_buff *skb;
 544         struct can_frame *cf;
 545         int err;
 546
 547         BUG_ON(netif_carrier_ok(dev));
 548
 549         /* No synchronization needed because the device is bus-off and
 550          * no messages can come in or go out.
 551          */
 552         can_flush_echo_skb(dev);
 553
 554         /* send restart message upstream */
 555         skb = alloc_can_err_skb(dev, &cf);
 556         if (!skb)
 557                 goto restart;
 558
 559         cf->can_id |= CAN_ERR_RESTARTED;
 560
 561         netif_rx(skb);
 562
 563         stats->rx_packets++;
 564         stats->rx_bytes += cf->can_dlc;
 565
 566 restart:
 567         netdev_dbg(dev, "restarted\n");
 568         priv->can_stats.restarts++;
 569
 570         /* Now restart the device */
 571         err = priv->do_set_mode(dev, CAN_MODE_START);
 572
 573         netif_carrier_on(dev);
 574         if (err)
 575                 netdev_err(dev, "Error %d during restart", err);
 576 }
 577
 578 static void can_restart_work(struct work_struct *work)
 579 {
 580         struct delayed_work *dwork = to_delayed_work(work);
 581         struct can_priv *priv = container_of(dwork, struct can_priv,
 582                                              restart_work);
 583
 584         can_restart(priv->dev);
 585 }
 586
 587 int can_restart_now(struct net_device *dev)
 588 {
 589         struct can_priv *priv = netdev_priv(dev);
 590
 591         /* A manual restart is only permitted if automatic restart is
 592          * disabled and the device is in the bus-off state
 593          */
 594         if (priv->restart_ms)
 595                 return -EINVAL;
 596         if (priv->state != CAN_STATE_BUS_OFF)
 597                 return -EBUSY;
 598
 599         cancel_delayed_work_sync(&priv->restart_work);
 600         can_restart(dev);
 601
 602         return 0;
 603 }
 604
 605 /* CAN bus-off
 606  *
 607  * This functions should be called when the device goes bus-off to
 608  * tell the netif layer that no more packets can be sent or received.
 609  * If enabled, a timer is started to trigger bus-off recovery.
 610  */
 611 void can_bus_off(struct net_device *dev)
 612 {
 613         struct can_priv *priv = netdev_priv(dev);
 614
 615         netdev_info(dev, "bus-off\n");
 616
 617         netif_carrier_off(dev);
 618
 619         if (priv->restart_ms)
 620                 schedule_delayed_work(&priv->restart_work,
 621                                       msecs_to_jiffies(priv->restart_ms));
 622 }
 623 EXPORT_SYMBOL_GPL(can_bus_off);
 624
 625 static void can_setup(struct net_device *dev)
 626 {
 627         dev->type = ARPHRD_CAN;
 628         dev->mtu = CAN_MTU;
 629         dev->hard_header_len = 0;
 630         dev->addr_len = 0;
 631         dev->tx_queue_len = 10;
 632
 633         /* New-style flags. */
 634         dev->flags = IFF_NOARP;
 635         dev->features = NETIF_F_HW_CSUM;
 636 }
 637
 638 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 639 {
 640         struct sk_buff *skb;
 641
 642         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 643                                sizeof(struct can_frame));
 644         if (unlikely(!skb))
 645                 return NULL;
 646
 647         skb->protocol = htons(ETH_P_CAN);
 648         skb->pkt_type = PACKET_BROADCAST;
 649         skb->ip_summed = CHECKSUM_UNNECESSARY;
 650
 651         skb_reset_mac_header(skb);
 652         skb_reset_network_header(skb);
 653         skb_reset_transport_header(skb);
 654
 655         can_skb_reserve(skb);
 656         can_skb_prv(skb)->ifindex = dev->ifindex;
 657         can_skb_prv(skb)->skbcnt = 0;
 658
 659         *cf = skb_put_zero(skb, sizeof(struct can_frame));
 660
 661         return skb;
 662 }
 663 EXPORT_SYMBOL_GPL(alloc_can_skb);
 664
 665 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 666                                 struct canfd_frame **cfd)
 667 {
 668         struct sk_buff *skb;
 669
 670         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 671                                sizeof(struct canfd_frame));
 672         if (unlikely(!skb))
 673                 return NULL;
 674
 675         skb->protocol = htons(ETH_P_CANFD);
 676         skb->pkt_type = PACKET_BROADCAST;
 677         skb->ip_summed = CHECKSUM_UNNECESSARY;
 678
 679         skb_reset_mac_header(skb);
 680         skb_reset_network_header(skb);
 681         skb_reset_transport_header(skb);
 682
 683         can_skb_reserve(skb);
 684         can_skb_prv(skb)->ifindex = dev->ifindex;
 685         can_skb_prv(skb)->skbcnt = 0;
 686
 687         *cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
 688
 689         return skb;
 690 }
 691 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 692
 693 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 694 {
 695         struct sk_buff *skb;
 696
 697         skb = alloc_can_skb(dev, cf);
 698         if (unlikely(!skb))
 699                 return NULL;
 700
 701         (*cf)->can_id = CAN_ERR_FLAG;
 702         (*cf)->can_dlc = CAN_ERR_DLC;
 703
 704         return skb;
 705 }
 706 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 707
 708 /* Allocate and setup space for the CAN network device */
 709 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
 710                                     unsigned int txqs, unsigned int rxqs)
 711 {
 712         struct net_device *dev;
 713         struct can_priv *priv;
 714         int size;
 715
 716         /* We put the driver's priv, the CAN mid layer priv and the
 717          * echo skb into the netdevice's priv. The memory layout for
 718          * the netdev_priv is like this:
 719          *
 720          * +-------------------------+
 721          * | driver's priv           |
 722          * +-------------------------+
 723          * | struct can_ml_priv      |
 724          * +-------------------------+
 725          * | array of struct sk_buff |
 726          * +-------------------------+
 727          */
 728
 729         size = ALIGN(sizeof_priv, NETDEV_ALIGN) + sizeof(struct can_ml_priv);
 730
 731         if (echo_skb_max)
 732                 size = ALIGN(size, sizeof(struct sk_buff *)) +
 733                         echo_skb_max * sizeof(struct sk_buff *);
 734
 735         dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup,
 736                                txqs, rxqs);
 737         if (!dev)
 738                 return NULL;
 739
 740         priv = netdev_priv(dev);
 741         priv->dev = dev;
 742
 743         dev->ml_priv = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN);
 744
 745         if (echo_skb_max) {
 746                 priv->echo_skb_max = echo_skb_max;
 747                 priv->echo_skb = (void *)priv +
 748                         (size - echo_skb_max * sizeof(struct sk_buff *));
 749         }
 750
 751         priv->state = CAN_STATE_STOPPED;
 752
 753         INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
 754
 755         return dev;
 756 }
 757 EXPORT_SYMBOL_GPL(alloc_candev_mqs);
 758
 759 /* Free space of the CAN network device */
 760 void free_candev(struct net_device *dev)
 761 {
 762         free_netdev(dev);
 763 }
 764 EXPORT_SYMBOL_GPL(free_candev);
 765
 766 /* changing MTU and control mode for CAN/CANFD devices */
 767 int can_change_mtu(struct net_device *dev, int new_mtu)
 768 {
 769         struct can_priv *priv = netdev_priv(dev);
 770
 771         /* Do not allow changing the MTU while running */
 772         if (dev->flags & IFF_UP)
 773                 return -EBUSY;
 774
 775         /* allow change of MTU according to the CANFD ability of the device */
 776         switch (new_mtu) {
 777         case CAN_MTU:
 778                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 779                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 780                         return -EINVAL;
 781
 782                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 783                 break;
 784
 785         case CANFD_MTU:
 786                 /* check for potential CANFD ability */
 787                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 788                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 789                         return -EINVAL;
 790
 791                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 792                 break;
 793
 794         default:
 795                 return -EINVAL;
 796         }
 797
 798         dev->mtu = new_mtu;
 799         return 0;
 800 }
 801 EXPORT_SYMBOL_GPL(can_change_mtu);
 802
 803 /* Common open function when the device gets opened.
 804  *
 805  * This function should be called in the open function of the device
 806  * driver.
 807  */
 808 int open_candev(struct net_device *dev)
 809 {
 810         struct can_priv *priv = netdev_priv(dev);
 811
 812         if (!priv->bittiming.bitrate) {
 813                 netdev_err(dev, "bit-timing not yet defined\n");
 814                 return -EINVAL;
 815         }
 816
 817         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 818         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 819             (!priv->data_bittiming.bitrate ||
 820              priv->data_bittiming.bitrate < priv->bittiming.bitrate)) {
 821                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 822                 return -EINVAL;
 823         }
 824
 825         /* Switch carrier on if device was stopped while in bus-off state */
 826         if (!netif_carrier_ok(dev))
 827                 netif_carrier_on(dev);
 828
 829         return 0;
 830 }
 831 EXPORT_SYMBOL_GPL(open_candev);
 832
 833 #ifdef CONFIG_OF
 834 /* Common function that can be used to understand the limitation of
 835  * a transceiver when it provides no means to determine these limitations
 836  * at runtime.
 837  */
 838 void of_can_transceiver(struct net_device *dev)
 839 {
 840         struct device_node *dn;
 841         struct can_priv *priv = netdev_priv(dev);
 842         struct device_node *np = dev->dev.parent->of_node;
 843         int ret;
 844
 845         dn = of_get_child_by_name(np, "can-transceiver");
 846         if (!dn)
 847                 return;
 848
 849         ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max);
 850         of_node_put(dn);
 851         if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
 852                 netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
 853 }
 854 EXPORT_SYMBOL_GPL(of_can_transceiver);
 855 #endif
 856
 857 /* Common close function for cleanup before the device gets closed.
 858  *
 859  * This function should be called in the close function of the device
 860  * driver.
 861  */
 862 void close_candev(struct net_device *dev)
 863 {
 864         struct can_priv *priv = netdev_priv(dev);
 865
 866         cancel_delayed_work_sync(&priv->restart_work);
 867         can_flush_echo_skb(dev);
 868 }
 869 EXPORT_SYMBOL_GPL(close_candev);
 870
 871 /* CAN netlink interface */
 872 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 873         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 874         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 875         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 876         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 877         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 878         [IFLA_CAN_BITTIMING_CONST]
 879                                 = { .len = sizeof(struct can_bittiming_const) },
 880         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 881         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 882         [IFLA_CAN_DATA_BITTIMING]
 883                                 = { .len = sizeof(struct can_bittiming) },
 884         [IFLA_CAN_DATA_BITTIMING_CONST]
 885                                 = { .len = sizeof(struct can_bittiming_const) },
 886         [IFLA_CAN_TERMINATION]  = { .type = NLA_U16 },
 887 };
 888
 889 static int can_validate(struct nlattr *tb[], struct nlattr *data[],
 890                         struct netlink_ext_ack *extack)
 891 {
 892         bool is_can_fd = false;
 893
 894         /* Make sure that valid CAN FD configurations always consist of
 895          * - nominal/arbitration bittiming
 896          * - data bittiming
 897          * - control mode with CAN_CTRLMODE_FD set
 898          */
 899
 900         if (!data)
 901                 return 0;
 902
 903         if (data[IFLA_CAN_CTRLMODE]) {
 904                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 905
 906                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 907         }
 908
 909         if (is_can_fd) {
 910                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 911                         return -EOPNOTSUPP;
 912         }
 913
 914         if (data[IFLA_CAN_DATA_BITTIMING]) {
 915                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 916                         return -EOPNOTSUPP;
 917         }
 918
 919         return 0;
 920 }
 921
 922 static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 923                           struct nlattr *data[],
 924                           struct netlink_ext_ack *extack)
 925 {
 926         struct can_priv *priv = netdev_priv(dev);
 927         int err;
 928
 929         /* We need synchronization with dev->stop() */
 930         ASSERT_RTNL();
 931
 932         if (data[IFLA_CAN_BITTIMING]) {
 933                 struct can_bittiming bt;
 934
 935                 /* Do not allow changing bittiming while running */
 936                 if (dev->flags & IFF_UP)
 937                         return -EBUSY;
 938
 939                 /* Calculate bittiming parameters based on
 940                  * bittiming_const if set, otherwise pass bitrate
 941                  * directly via do_set_bitrate(). Bail out if neither
 942                  * is given.
 943                  */
 944                 if (!priv->bittiming_const && !priv->do_set_bittiming)
 945                         return -EOPNOTSUPP;
 946
 947                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 948                 err = can_get_bittiming(dev, &bt,
 949                                         priv->bittiming_const,
 950                                         priv->bitrate_const,
 951                                         priv->bitrate_const_cnt);
 952                 if (err)
 953                         return err;
 954
 955                 if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) {
 956                         netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n",
 957                                    priv->bitrate_max);
 958                         return -EINVAL;
 959                 }
 960
 961                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 962
 963                 if (priv->do_set_bittiming) {
 964                         /* Finally, set the bit-timing registers */
 965                         err = priv->do_set_bittiming(dev);
 966                         if (err)
 967                                 return err;
 968                 }
 969         }
 970
 971         if (data[IFLA_CAN_CTRLMODE]) {
 972                 struct can_ctrlmode *cm;
 973                 u32 ctrlstatic;
 974                 u32 maskedflags;
 975
 976                 /* Do not allow changing controller mode while running */
 977                 if (dev->flags & IFF_UP)
 978                         return -EBUSY;
 979                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 980                 ctrlstatic = priv->ctrlmode_static;
 981                 maskedflags = cm->flags & cm->mask;
 982
 983                 /* check whether provided bits are allowed to be passed */
 984                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
 985                         return -EOPNOTSUPP;
 986
 987                 /* do not check for static fd-non-iso if 'fd' is disabled */
 988                 if (!(maskedflags & CAN_CTRLMODE_FD))
 989                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
 990
 991                 /* make sure static options are provided by configuration */
 992                 if ((maskedflags & ctrlstatic) != ctrlstatic)
 993                         return -EOPNOTSUPP;
 994
 995                 /* clear bits to be modified and copy the flag values */
 996                 priv->ctrlmode &= ~cm->mask;
 997                 priv->ctrlmode |= maskedflags;
 998
 999                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
1000                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
1001                         dev->mtu = CANFD_MTU;
1002                 else
1003                         dev->mtu = CAN_MTU;
1004         }
1005
1006         if (data[IFLA_CAN_RESTART_MS]) {
1007                 /* Do not allow changing restart delay while running */
1008                 if (dev->flags & IFF_UP)
1009                         return -EBUSY;
1010                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
1011         }
1012
1013         if (data[IFLA_CAN_RESTART]) {
1014                 /* Do not allow a restart while not running */
1015                 if (!(dev->flags & IFF_UP))
1016                         return -EINVAL;
1017                 err = can_restart_now(dev);
1018                 if (err)
1019                         return err;
1020         }
1021
1022         if (data[IFLA_CAN_DATA_BITTIMING]) {
1023                 struct can_bittiming dbt;
1024
1025                 /* Do not allow changing bittiming while running */
1026                 if (dev->flags & IFF_UP)
1027                         return -EBUSY;
1028
1029                 /* Calculate bittiming parameters based on
1030                  * data_bittiming_const if set, otherwise pass bitrate
1031                  * directly via do_set_bitrate(). Bail out if neither
1032                  * is given.
1033                  */
1034                 if (!priv->data_bittiming_const && !priv->do_set_data_bittiming)
1035                         return -EOPNOTSUPP;
1036
1037                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
1038                        sizeof(dbt));
1039                 err = can_get_bittiming(dev, &dbt,
1040                                         priv->data_bittiming_const,
1041                                         priv->data_bitrate_const,
1042                                         priv->data_bitrate_const_cnt);
1043                 if (err)
1044                         return err;
1045
1046                 if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
1047                         netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
1048                                    priv->bitrate_max);
1049                         return -EINVAL;
1050                 }
1051
1052                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
1053
1054                 if (priv->do_set_data_bittiming) {
1055                         /* Finally, set the bit-timing registers */
1056                         err = priv->do_set_data_bittiming(dev);
1057                         if (err)
1058                                 return err;
1059                 }
1060         }
1061
1062         if (data[IFLA_CAN_TERMINATION]) {
1063                 const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]);
1064                 const unsigned int num_term = priv->termination_const_cnt;
1065                 unsigned int i;
1066
1067                 if (!priv->do_set_termination)
1068                         return -EOPNOTSUPP;
1069
1070                 /* check whether given value is supported by the interface */
1071                 for (i = 0; i < num_term; i++) {
1072                         if (termval == priv->termination_const[i])
1073                                 break;
1074                 }
1075                 if (i >= num_term)
1076                         return -EINVAL;
1077
1078                 /* Finally, set the termination value */
1079                 err = priv->do_set_termination(dev, termval);
1080                 if (err)
1081                         return err;
1082
1083                 priv->termination = termval;
1084         }
1085
1086         return 0;
1087 }
1088
1089 static size_t can_get_size(const struct net_device *dev)
1090 {
1091         struct can_priv *priv = netdev_priv(dev);
1092         size_t size = 0;
1093
1094         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
1095                 size += nla_total_size(sizeof(struct can_bittiming));
1096         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
1097                 size += nla_total_size(sizeof(struct can_bittiming_const));
1098         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
1099         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
1100         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
1101         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
1102         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
1103                 size += nla_total_size(sizeof(struct can_berr_counter));
1104         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
1105                 size += nla_total_size(sizeof(struct can_bittiming));
1106         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
1107                 size += nla_total_size(sizeof(struct can_bittiming_const));
1108         if (priv->termination_const) {
1109                 size += nla_total_size(sizeof(priv->termination));              /* IFLA_CAN_TERMINATION */
1110                 size += nla_total_size(sizeof(*priv->termination_const) *       /* IFLA_CAN_TERMINATION_CONST */
1111                                        priv->termination_const_cnt);
1112         }
1113         if (priv->bitrate_const)                                /* IFLA_CAN_BITRATE_CONST */
1114                 size += nla_total_size(sizeof(*priv->bitrate_const) *
1115                                        priv->bitrate_const_cnt);
1116         if (priv->data_bitrate_const)                           /* IFLA_CAN_DATA_BITRATE_CONST */
1117                 size += nla_total_size(sizeof(*priv->data_bitrate_const) *
1118                                        priv->data_bitrate_const_cnt);
1119         size += sizeof(priv->bitrate_max);                      /* IFLA_CAN_BITRATE_MAX */
1120
1121         return size;
1122 }
1123
1124 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
1125 {
1126         struct can_priv *priv = netdev_priv(dev);
1127         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
1128         struct can_berr_counter bec;
1129         enum can_state state = priv->state;
1130
1131         if (priv->do_get_state)
1132                 priv->do_get_state(dev, &state);
1133
1134         if ((priv->bittiming.bitrate &&
1135              nla_put(skb, IFLA_CAN_BITTIMING,
1136                      sizeof(priv->bittiming), &priv->bittiming)) ||
1137
1138             (priv->bittiming_const &&
1139              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1140                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1141
1142             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1143             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1144             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1145             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1146
1147             (priv->do_get_berr_counter &&
1148              !priv->do_get_berr_counter(dev, &bec) &&
1149              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1150
1151             (priv->data_bittiming.bitrate &&
1152              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1153                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1154
1155             (priv->data_bittiming_const &&
1156              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1157                      sizeof(*priv->data_bittiming_const),
1158                      priv->data_bittiming_const)) ||
1159
1160             (priv->termination_const &&
1161              (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||
1162               nla_put(skb, IFLA_CAN_TERMINATION_CONST,
1163                       sizeof(*priv->termination_const) *
1164                       priv->termination_const_cnt,
1165                       priv->termination_const))) ||
1166
1167             (priv->bitrate_const &&
1168              nla_put(skb, IFLA_CAN_BITRATE_CONST,
1169                      sizeof(*priv->bitrate_const) *
1170                      priv->bitrate_const_cnt,
1171                      priv->bitrate_const)) ||
1172
1173             (priv->data_bitrate_const &&
1174              nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
1175                      sizeof(*priv->data_bitrate_const) *
1176                      priv->data_bitrate_const_cnt,
1177                      priv->data_bitrate_const)) ||
1178
1179             (nla_put(skb, IFLA_CAN_BITRATE_MAX,
1180                      sizeof(priv->bitrate_max),
1181                      &priv->bitrate_max))
1182             )
1183
1184                 return -EMSGSIZE;
1185
1186         return 0;
1187 }
1188
1189 static size_t can_get_xstats_size(const struct net_device *dev)
1190 {
1191         return sizeof(struct can_device_stats);
1192 }
1193
1194 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1195 {
1196         struct can_priv *priv = netdev_priv(dev);
1197
1198         if (nla_put(skb, IFLA_INFO_XSTATS,
1199                     sizeof(priv->can_stats), &priv->can_stats))
1200                 goto nla_put_failure;
1201         return 0;
1202
1203 nla_put_failure:
1204         return -EMSGSIZE;
1205 }
1206
1207 static int can_newlink(struct net *src_net, struct net_device *dev,
1208                        struct nlattr *tb[], struct nlattr *data[],
1209                        struct netlink_ext_ack *extack)
1210 {
1211         return -EOPNOTSUPP;
1212 }
1213
1214 static void can_dellink(struct net_device *dev, struct list_head *head)
1215 {
1216 }
1217
1218 static struct rtnl_link_ops can_link_ops __read_mostly = {
1219         .kind           = "can",
1220         .maxtype        = IFLA_CAN_MAX,
1221         .policy         = can_policy,
1222         .setup          = can_setup,
1223         .validate       = can_validate,
1224         .newlink        = can_newlink,
1225         .changelink     = can_changelink,
1226         .dellink        = can_dellink,
1227         .get_size       = can_get_size,
1228         .fill_info      = can_fill_info,
1229         .get_xstats_size = can_get_xstats_size,
1230         .fill_xstats    = can_fill_xstats,
1231 };
1232
1233 /* Register the CAN network device */
1234 int register_candev(struct net_device *dev)
1235 {
1236         struct can_priv *priv = netdev_priv(dev);
1237
1238         /* Ensure termination_const, termination_const_cnt and
1239          * do_set_termination consistency. All must be either set or
1240          * unset.
1241          */
1242         if ((!priv->termination_const != !priv->termination_const_cnt) ||
1243             (!priv->termination_const != !priv->do_set_termination))
1244                 return -EINVAL;
1245
1246         if (!priv->bitrate_const != !priv->bitrate_const_cnt)
1247                 return -EINVAL;
1248
1249         if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
1250                 return -EINVAL;
1251
1252         dev->rtnl_link_ops = &can_link_ops;
1253         netif_carrier_off(dev);
1254
1255         return register_netdev(dev);
1256 }
1257 EXPORT_SYMBOL_GPL(register_candev);
1258
1259 /* Unregister the CAN network device */
1260 void unregister_candev(struct net_device *dev)
1261 {
1262         unregister_netdev(dev);
1263 }
1264 EXPORT_SYMBOL_GPL(unregister_candev);
1265
1266 /* Test if a network device is a candev based device
1267  * and return the can_priv* if so.
1268  */
1269 struct can_priv *safe_candev_priv(struct net_device *dev)
1270 {
1271         if (dev->type != ARPHRD_CAN || dev->rtnl_link_ops != &can_link_ops)
1272                 return NULL;
1273
1274         return netdev_priv(dev);
1275 }
1276 EXPORT_SYMBOL_GPL(safe_candev_priv);
1277
1278 static __init int can_dev_init(void)
1279 {
1280         int err;
1281
1282         can_led_notifier_init();
1283
1284         err = rtnl_link_register(&can_link_ops);
1285         if (!err)
1286                 pr_info(MOD_DESC "\n");
1287
1288         return err;
1289 }
1290 module_init(can_dev_init);
1291
1292 static __exit void can_dev_exit(void)
1293 {
1294         rtnl_link_unregister(&can_link_ops);
1295
1296         can_led_notifier_exit();
1297 }
1298 module_exit(can_dev_exit);
1299
1300 MODULE_ALIAS_RTNL_LINK("can");