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                 err = -ENOMEM;
 558                 goto restart;
 559         }
 560         cf->can_id |= CAN_ERR_RESTARTED;
 561
 562         netif_rx(skb);
 563
 564         stats->rx_packets++;
 565         stats->rx_bytes += cf->can_dlc;
 566
 567 restart:
 568         netdev_dbg(dev, "restarted\n");
 569         priv->can_stats.restarts++;
 570
 571         /* Now restart the device */
 572         err = priv->do_set_mode(dev, CAN_MODE_START);
 573
 574         netif_carrier_on(dev);
 575         if (err)
 576                 netdev_err(dev, "Error %d during restart", err);
 577 }
 578
 579 static void can_restart_work(struct work_struct *work)
 580 {
 581         struct delayed_work *dwork = to_delayed_work(work);
 582         struct can_priv *priv = container_of(dwork, struct can_priv,
 583                                              restart_work);
 584
 585         can_restart(priv->dev);
 586 }
 587
 588 int can_restart_now(struct net_device *dev)
 589 {
 590         struct can_priv *priv = netdev_priv(dev);
 591
 592         /* A manual restart is only permitted if automatic restart is
 593          * disabled and the device is in the bus-off state
 594          */
 595         if (priv->restart_ms)
 596                 return -EINVAL;
 597         if (priv->state != CAN_STATE_BUS_OFF)
 598                 return -EBUSY;
 599
 600         cancel_delayed_work_sync(&priv->restart_work);
 601         can_restart(dev);
 602
 603         return 0;
 604 }
 605
 606 /* CAN bus-off
 607  *
 608  * This functions should be called when the device goes bus-off to
 609  * tell the netif layer that no more packets can be sent or received.
 610  * If enabled, a timer is started to trigger bus-off recovery.
 611  */
 612 void can_bus_off(struct net_device *dev)
 613 {
 614         struct can_priv *priv = netdev_priv(dev);
 615
 616         netdev_info(dev, "bus-off\n");
 617
 618         netif_carrier_off(dev);
 619
 620         if (priv->restart_ms)
 621                 schedule_delayed_work(&priv->restart_work,
 622                                       msecs_to_jiffies(priv->restart_ms));
 623 }
 624 EXPORT_SYMBOL_GPL(can_bus_off);
 625
 626 static void can_setup(struct net_device *dev)
 627 {
 628         dev->type = ARPHRD_CAN;
 629         dev->mtu = CAN_MTU;
 630         dev->hard_header_len = 0;
 631         dev->addr_len = 0;
 632         dev->tx_queue_len = 10;
 633
 634         /* New-style flags. */
 635         dev->flags = IFF_NOARP;
 636         dev->features = NETIF_F_HW_CSUM;
 637 }
 638
 639 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 640 {
 641         struct sk_buff *skb;
 642
 643         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 644                                sizeof(struct can_frame));
 645         if (unlikely(!skb))
 646                 return NULL;
 647
 648         skb->protocol = htons(ETH_P_CAN);
 649         skb->pkt_type = PACKET_BROADCAST;
 650         skb->ip_summed = CHECKSUM_UNNECESSARY;
 651
 652         skb_reset_mac_header(skb);
 653         skb_reset_network_header(skb);
 654         skb_reset_transport_header(skb);
 655
 656         can_skb_reserve(skb);
 657         can_skb_prv(skb)->ifindex = dev->ifindex;
 658         can_skb_prv(skb)->skbcnt = 0;
 659
 660         *cf = skb_put_zero(skb, sizeof(struct can_frame));
 661
 662         return skb;
 663 }
 664 EXPORT_SYMBOL_GPL(alloc_can_skb);
 665
 666 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 667                                 struct canfd_frame **cfd)
 668 {
 669         struct sk_buff *skb;
 670
 671         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 672                                sizeof(struct canfd_frame));
 673         if (unlikely(!skb))
 674                 return NULL;
 675
 676         skb->protocol = htons(ETH_P_CANFD);
 677         skb->pkt_type = PACKET_BROADCAST;
 678         skb->ip_summed = CHECKSUM_UNNECESSARY;
 679
 680         skb_reset_mac_header(skb);
 681         skb_reset_network_header(skb);
 682         skb_reset_transport_header(skb);
 683
 684         can_skb_reserve(skb);
 685         can_skb_prv(skb)->ifindex = dev->ifindex;
 686         can_skb_prv(skb)->skbcnt = 0;
 687
 688         *cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
 689
 690         return skb;
 691 }
 692 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 693
 694 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 695 {
 696         struct sk_buff *skb;
 697
 698         skb = alloc_can_skb(dev, cf);
 699         if (unlikely(!skb))
 700                 return NULL;
 701
 702         (*cf)->can_id = CAN_ERR_FLAG;
 703         (*cf)->can_dlc = CAN_ERR_DLC;
 704
 705         return skb;
 706 }
 707 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 708
 709 /* Allocate and setup space for the CAN network device */
 710 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
 711                                     unsigned int txqs, unsigned int rxqs)
 712 {
 713         struct net_device *dev;
 714         struct can_priv *priv;
 715         int size;
 716
 717         /* We put the driver's priv, the CAN mid layer priv and the
 718          * echo skb into the netdevice's priv. The memory layout for
 719          * the netdev_priv is like this:
 720          *
 721          * +-------------------------+
 722          * | driver's priv           |
 723          * +-------------------------+
 724          * | struct can_ml_priv      |
 725          * +-------------------------+
 726          * | array of struct sk_buff |
 727          * +-------------------------+
 728          */
 729
 730         size = ALIGN(sizeof_priv, NETDEV_ALIGN) + sizeof(struct can_ml_priv);
 731
 732         if (echo_skb_max)
 733                 size = ALIGN(size, sizeof(struct sk_buff *)) +
 734                         echo_skb_max * sizeof(struct sk_buff *);
 735
 736         dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup,
 737                                txqs, rxqs);
 738         if (!dev)
 739                 return NULL;
 740
 741         priv = netdev_priv(dev);
 742         priv->dev = dev;
 743
 744         dev->ml_priv = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN);
 745
 746         if (echo_skb_max) {
 747                 priv->echo_skb_max = echo_skb_max;
 748                 priv->echo_skb = (void *)priv +
 749                         (size - echo_skb_max * 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 /* Free space of the CAN network device */
 761 void free_candev(struct net_device *dev)
 762 {
 763         free_netdev(dev);
 764 }
 765 EXPORT_SYMBOL_GPL(free_candev);
 766
 767 /* changing MTU and control mode for CAN/CANFD devices */
 768 int can_change_mtu(struct net_device *dev, int new_mtu)
 769 {
 770         struct can_priv *priv = netdev_priv(dev);
 771
 772         /* Do not allow changing the MTU while running */
 773         if (dev->flags & IFF_UP)
 774                 return -EBUSY;
 775
 776         /* allow change of MTU according to the CANFD ability of the device */
 777         switch (new_mtu) {
 778         case CAN_MTU:
 779                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 780                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 781                         return -EINVAL;
 782
 783                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 784                 break;
 785
 786         case CANFD_MTU:
 787                 /* check for potential CANFD ability */
 788                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 789                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 790                         return -EINVAL;
 791
 792                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 793                 break;
 794
 795         default:
 796                 return -EINVAL;
 797         }
 798
 799         dev->mtu = new_mtu;
 800         return 0;
 801 }
 802 EXPORT_SYMBOL_GPL(can_change_mtu);
 803
 804 /* Common open function when the device gets opened.
 805  *
 806  * This function should be called in the open function of the device
 807  * driver.
 808  */
 809 int open_candev(struct net_device *dev)
 810 {
 811         struct can_priv *priv = netdev_priv(dev);
 812
 813         if (!priv->bittiming.bitrate) {
 814                 netdev_err(dev, "bit-timing not yet defined\n");
 815                 return -EINVAL;
 816         }
 817
 818         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 819         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 820             (!priv->data_bittiming.bitrate ||
 821              priv->data_bittiming.bitrate < priv->bittiming.bitrate)) {
 822                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 823                 return -EINVAL;
 824         }
 825
 826         /* Switch carrier on if device was stopped while in bus-off state */
 827         if (!netif_carrier_ok(dev))
 828                 netif_carrier_on(dev);
 829
 830         return 0;
 831 }
 832 EXPORT_SYMBOL_GPL(open_candev);
 833
 834 #ifdef CONFIG_OF
 835 /* Common function that can be used to understand the limitation of
 836  * a transceiver when it provides no means to determine these limitations
 837  * at runtime.
 838  */
 839 void of_can_transceiver(struct net_device *dev)
 840 {
 841         struct device_node *dn;
 842         struct can_priv *priv = netdev_priv(dev);
 843         struct device_node *np = dev->dev.parent->of_node;
 844         int ret;
 845
 846         dn = of_get_child_by_name(np, "can-transceiver");
 847         if (!dn)
 848                 return;
 849
 850         ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max);
 851         of_node_put(dn);
 852         if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
 853                 netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
 854 }
 855 EXPORT_SYMBOL_GPL(of_can_transceiver);
 856 #endif
 857
 858 /* Common close function for cleanup before the device gets closed.
 859  *
 860  * This function should be called in the close function of the device
 861  * driver.
 862  */
 863 void close_candev(struct net_device *dev)
 864 {
 865         struct can_priv *priv = netdev_priv(dev);
 866
 867         cancel_delayed_work_sync(&priv->restart_work);
 868         can_flush_echo_skb(dev);
 869 }
 870 EXPORT_SYMBOL_GPL(close_candev);
 871
 872 /* CAN netlink interface */
 873 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 874         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 875         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 876         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 877         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 878         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 879         [IFLA_CAN_BITTIMING_CONST]
 880                                 = { .len = sizeof(struct can_bittiming_const) },
 881         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 882         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 883         [IFLA_CAN_DATA_BITTIMING]
 884                                 = { .len = sizeof(struct can_bittiming) },
 885         [IFLA_CAN_DATA_BITTIMING_CONST]
 886                                 = { .len = sizeof(struct can_bittiming_const) },
 887         [IFLA_CAN_TERMINATION]  = { .type = NLA_U16 },
 888 };
 889
 890 static int can_validate(struct nlattr *tb[], struct nlattr *data[],
 891                         struct netlink_ext_ack *extack)
 892 {
 893         bool is_can_fd = false;
 894
 895         /* Make sure that valid CAN FD configurations always consist of
 896          * - nominal/arbitration bittiming
 897          * - data bittiming
 898          * - control mode with CAN_CTRLMODE_FD set
 899          */
 900
 901         if (!data)
 902                 return 0;
 903
 904         if (data[IFLA_CAN_CTRLMODE]) {
 905                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 906
 907                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 908         }
 909
 910         if (is_can_fd) {
 911                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 912                         return -EOPNOTSUPP;
 913         }
 914
 915         if (data[IFLA_CAN_DATA_BITTIMING]) {
 916                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 917                         return -EOPNOTSUPP;
 918         }
 919
 920         return 0;
 921 }
 922
 923 static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 924                           struct nlattr *data[],
 925                           struct netlink_ext_ack *extack)
 926 {
 927         struct can_priv *priv = netdev_priv(dev);
 928         int err;
 929
 930         /* We need synchronization with dev->stop() */
 931         ASSERT_RTNL();
 932
 933         if (data[IFLA_CAN_BITTIMING]) {
 934                 struct can_bittiming bt;
 935
 936                 /* Do not allow changing bittiming while running */
 937                 if (dev->flags & IFF_UP)
 938                         return -EBUSY;
 939
 940                 /* Calculate bittiming parameters based on
 941                  * bittiming_const if set, otherwise pass bitrate
 942                  * directly via do_set_bitrate(). Bail out if neither
 943                  * is given.
 944                  */
 945                 if (!priv->bittiming_const && !priv->do_set_bittiming)
 946                         return -EOPNOTSUPP;
 947
 948                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 949                 err = can_get_bittiming(dev, &bt,
 950                                         priv->bittiming_const,
 951                                         priv->bitrate_const,
 952                                         priv->bitrate_const_cnt);
 953                 if (err)
 954                         return err;
 955
 956                 if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) {
 957                         netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n",
 958                                    priv->bitrate_max);
 959                         return -EINVAL;
 960                 }
 961
 962                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 963
 964                 if (priv->do_set_bittiming) {
 965                         /* Finally, set the bit-timing registers */
 966                         err = priv->do_set_bittiming(dev);
 967                         if (err)
 968                                 return err;
 969                 }
 970         }
 971
 972         if (data[IFLA_CAN_CTRLMODE]) {
 973                 struct can_ctrlmode *cm;
 974                 u32 ctrlstatic;
 975                 u32 maskedflags;
 976
 977                 /* Do not allow changing controller mode while running */
 978                 if (dev->flags & IFF_UP)
 979                         return -EBUSY;
 980                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 981                 ctrlstatic = priv->ctrlmode_static;
 982                 maskedflags = cm->flags & cm->mask;
 983
 984                 /* check whether provided bits are allowed to be passed */
 985                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
 986                         return -EOPNOTSUPP;
 987
 988                 /* do not check for static fd-non-iso if 'fd' is disabled */
 989                 if (!(maskedflags & CAN_CTRLMODE_FD))
 990                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
 991
 992                 /* make sure static options are provided by configuration */
 993                 if ((maskedflags & ctrlstatic) != ctrlstatic)
 994                         return -EOPNOTSUPP;
 995
 996                 /* clear bits to be modified and copy the flag values */
 997                 priv->ctrlmode &= ~cm->mask;
 998                 priv->ctrlmode |= maskedflags;
 999
1000                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
1001                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
1002                         dev->mtu = CANFD_MTU;
1003                 else
1004                         dev->mtu = CAN_MTU;
1005         }
1006
1007         if (data[IFLA_CAN_RESTART_MS]) {
1008                 /* Do not allow changing restart delay while running */
1009                 if (dev->flags & IFF_UP)
1010                         return -EBUSY;
1011                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
1012         }
1013
1014         if (data[IFLA_CAN_RESTART]) {
1015                 /* Do not allow a restart while not running */
1016                 if (!(dev->flags & IFF_UP))
1017                         return -EINVAL;
1018                 err = can_restart_now(dev);
1019                 if (err)
1020                         return err;
1021         }
1022
1023         if (data[IFLA_CAN_DATA_BITTIMING]) {
1024                 struct can_bittiming dbt;
1025
1026                 /* Do not allow changing bittiming while running */
1027                 if (dev->flags & IFF_UP)
1028                         return -EBUSY;
1029
1030                 /* Calculate bittiming parameters based on
1031                  * data_bittiming_const if set, otherwise pass bitrate
1032                  * directly via do_set_bitrate(). Bail out if neither
1033                  * is given.
1034                  */
1035                 if (!priv->data_bittiming_const && !priv->do_set_data_bittiming)
1036                         return -EOPNOTSUPP;
1037
1038                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
1039                        sizeof(dbt));
1040                 err = can_get_bittiming(dev, &dbt,
1041                                         priv->data_bittiming_const,
1042                                         priv->data_bitrate_const,
1043                                         priv->data_bitrate_const_cnt);
1044                 if (err)
1045                         return err;
1046
1047                 if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
1048                         netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
1049                                    priv->bitrate_max);
1050                         return -EINVAL;
1051                 }
1052
1053                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
1054
1055                 if (priv->do_set_data_bittiming) {
1056                         /* Finally, set the bit-timing registers */
1057                         err = priv->do_set_data_bittiming(dev);
1058                         if (err)
1059                                 return err;
1060                 }
1061         }
1062
1063         if (data[IFLA_CAN_TERMINATION]) {
1064                 const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]);
1065                 const unsigned int num_term = priv->termination_const_cnt;
1066                 unsigned int i;
1067
1068                 if (!priv->do_set_termination)
1069                         return -EOPNOTSUPP;
1070
1071                 /* check whether given value is supported by the interface */
1072                 for (i = 0; i < num_term; i++) {
1073                         if (termval == priv->termination_const[i])
1074                                 break;
1075                 }
1076                 if (i >= num_term)
1077                         return -EINVAL;
1078
1079                 /* Finally, set the termination value */
1080                 err = priv->do_set_termination(dev, termval);
1081                 if (err)
1082                         return err;
1083
1084                 priv->termination = termval;
1085         }
1086
1087         return 0;
1088 }
1089
1090 static size_t can_get_size(const struct net_device *dev)
1091 {
1092         struct can_priv *priv = netdev_priv(dev);
1093         size_t size = 0;
1094
1095         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
1096                 size += nla_total_size(sizeof(struct can_bittiming));
1097         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
1098                 size += nla_total_size(sizeof(struct can_bittiming_const));
1099         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
1100         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
1101         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
1102         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
1103         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
1104                 size += nla_total_size(sizeof(struct can_berr_counter));
1105         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
1106                 size += nla_total_size(sizeof(struct can_bittiming));
1107         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
1108                 size += nla_total_size(sizeof(struct can_bittiming_const));
1109         if (priv->termination_const) {
1110                 size += nla_total_size(sizeof(priv->termination));              /* IFLA_CAN_TERMINATION */
1111                 size += nla_total_size(sizeof(*priv->termination_const) *       /* IFLA_CAN_TERMINATION_CONST */
1112                                        priv->termination_const_cnt);
1113         }
1114         if (priv->bitrate_const)                                /* IFLA_CAN_BITRATE_CONST */
1115                 size += nla_total_size(sizeof(*priv->bitrate_const) *
1116                                        priv->bitrate_const_cnt);
1117         if (priv->data_bitrate_const)                           /* IFLA_CAN_DATA_BITRATE_CONST */
1118                 size += nla_total_size(sizeof(*priv->data_bitrate_const) *
1119                                        priv->data_bitrate_const_cnt);
1120         size += sizeof(priv->bitrate_max);                      /* IFLA_CAN_BITRATE_MAX */
1121
1122         return size;
1123 }
1124
1125 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
1126 {
1127         struct can_priv *priv = netdev_priv(dev);
1128         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
1129         struct can_berr_counter bec;
1130         enum can_state state = priv->state;
1131
1132         if (priv->do_get_state)
1133                 priv->do_get_state(dev, &state);
1134
1135         if ((priv->bittiming.bitrate &&
1136              nla_put(skb, IFLA_CAN_BITTIMING,
1137                      sizeof(priv->bittiming), &priv->bittiming)) ||
1138
1139             (priv->bittiming_const &&
1140              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1141                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1142
1143             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1144             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1145             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1146             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1147
1148             (priv->do_get_berr_counter &&
1149              !priv->do_get_berr_counter(dev, &bec) &&
1150              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1151
1152             (priv->data_bittiming.bitrate &&
1153              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1154                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1155
1156             (priv->data_bittiming_const &&
1157              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1158                      sizeof(*priv->data_bittiming_const),
1159                      priv->data_bittiming_const)) ||
1160
1161             (priv->termination_const &&
1162              (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||
1163               nla_put(skb, IFLA_CAN_TERMINATION_CONST,
1164                       sizeof(*priv->termination_const) *
1165                       priv->termination_const_cnt,
1166                       priv->termination_const))) ||
1167
1168             (priv->bitrate_const &&
1169              nla_put(skb, IFLA_CAN_BITRATE_CONST,
1170                      sizeof(*priv->bitrate_const) *
1171                      priv->bitrate_const_cnt,
1172                      priv->bitrate_const)) ||
1173
1174             (priv->data_bitrate_const &&
1175              nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
1176                      sizeof(*priv->data_bitrate_const) *
1177                      priv->data_bitrate_const_cnt,
1178                      priv->data_bitrate_const)) ||
1179
1180             (nla_put(skb, IFLA_CAN_BITRATE_MAX,
1181                      sizeof(priv->bitrate_max),
1182                      &priv->bitrate_max))
1183             )
1184
1185                 return -EMSGSIZE;
1186
1187         return 0;
1188 }
1189
1190 static size_t can_get_xstats_size(const struct net_device *dev)
1191 {
1192         return sizeof(struct can_device_stats);
1193 }
1194
1195 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1196 {
1197         struct can_priv *priv = netdev_priv(dev);
1198
1199         if (nla_put(skb, IFLA_INFO_XSTATS,
1200                     sizeof(priv->can_stats), &priv->can_stats))
1201                 goto nla_put_failure;
1202         return 0;
1203
1204 nla_put_failure:
1205         return -EMSGSIZE;
1206 }
1207
1208 static int can_newlink(struct net *src_net, struct net_device *dev,
1209                        struct nlattr *tb[], struct nlattr *data[],
1210                        struct netlink_ext_ack *extack)
1211 {
1212         return -EOPNOTSUPP;
1213 }
1214
1215 static void can_dellink(struct net_device *dev, struct list_head *head)
1216 {
1217 }
1218
1219 static struct rtnl_link_ops can_link_ops __read_mostly = {
1220         .kind           = "can",
1221         .maxtype        = IFLA_CAN_MAX,
1222         .policy         = can_policy,
1223         .setup          = can_setup,
1224         .validate       = can_validate,
1225         .newlink        = can_newlink,
1226         .changelink     = can_changelink,
1227         .dellink        = can_dellink,
1228         .get_size       = can_get_size,
1229         .fill_info      = can_fill_info,
1230         .get_xstats_size = can_get_xstats_size,
1231         .fill_xstats    = can_fill_xstats,
1232 };
1233
1234 /* Register the CAN network device */
1235 int register_candev(struct net_device *dev)
1236 {
1237         struct can_priv *priv = netdev_priv(dev);
1238
1239         /* Ensure termination_const, termination_const_cnt and
1240          * do_set_termination consistency. All must be either set or
1241          * unset.
1242          */
1243         if ((!priv->termination_const != !priv->termination_const_cnt) ||
1244             (!priv->termination_const != !priv->do_set_termination))
1245                 return -EINVAL;
1246
1247         if (!priv->bitrate_const != !priv->bitrate_const_cnt)
1248                 return -EINVAL;
1249
1250         if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
1251                 return -EINVAL;
1252
1253         dev->rtnl_link_ops = &can_link_ops;
1254         netif_carrier_off(dev);
1255
1256         return register_netdev(dev);
1257 }
1258 EXPORT_SYMBOL_GPL(register_candev);
1259
1260 /* Unregister the CAN network device */
1261 void unregister_candev(struct net_device *dev)
1262 {
1263         unregister_netdev(dev);
1264 }
1265 EXPORT_SYMBOL_GPL(unregister_candev);
1266
1267 /* Test if a network device is a candev based device
1268  * and return the can_priv* if so.
1269  */
1270 struct can_priv *safe_candev_priv(struct net_device *dev)
1271 {
1272         if (dev->type != ARPHRD_CAN || dev->rtnl_link_ops != &can_link_ops)
1273                 return NULL;
1274
1275         return netdev_priv(dev);
1276 }
1277 EXPORT_SYMBOL_GPL(safe_candev_priv);
1278
1279 static __init int can_dev_init(void)
1280 {
1281         int err;
1282
1283         can_led_notifier_init();
1284
1285         err = rtnl_link_register(&can_link_ops);
1286         if (!err)
1287                 pr_info(MOD_DESC "\n");
1288
1289         return err;
1290 }
1291 module_init(can_dev_init);
1292
1293 static __exit void can_dev_exit(void)
1294 {
1295         rtnl_link_unregister(&can_link_ops);
1296
1297         can_led_notifier_exit();
1298 }
1299 module_exit(can_dev_exit);
1300
1301 MODULE_ALIAS_RTNL_LINK("can");