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 <[email protected]>
   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 <[email protected]>");
  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
  64 /* Bit-timing calculation derived from:
  65  *
  66  * Code based on LinCAN sources and H8S2638 project
  67  * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
  68  * Copyright 2005      Stanislav Marek
  69  * email: [email protected]
  70  *
  71  * Calculates proper bit-timing parameters for a specified bit-rate
  72  * and sample-point, which can then be used to set the bit-timing
  73  * registers of the CAN controller. You can find more information
  74  * in the header file linux/can/netlink.h.
  75  */
  76 static int
  77 can_update_sample_point(const struct can_bittiming_const *btc,
  78                         unsigned int sample_point_nominal, unsigned int tseg,
  79                         unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
  80                         unsigned int *sample_point_error_ptr)
  81 {
  82         unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
  83         unsigned int sample_point, best_sample_point = 0;
  84         unsigned int tseg1, tseg2;
  85         int i;
  86
  87         for (i = 0; i <= 1; i++) {
  88                 tseg2 = tseg + CAN_SYNC_SEG -
  89                         (sample_point_nominal * (tseg + CAN_SYNC_SEG)) /
  90                         1000 - i;
  91                 tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
  92                 tseg1 = tseg - tseg2;
  93                 if (tseg1 > btc->tseg1_max) {
  94                         tseg1 = btc->tseg1_max;
  95                         tseg2 = tseg - tseg1;
  96                 }
  97
  98                 sample_point = 1000 * (tseg + CAN_SYNC_SEG - tseg2) /
  99                         (tseg + CAN_SYNC_SEG);
 100                 sample_point_error = abs(sample_point_nominal - sample_point);
 101
 102                 if (sample_point <= sample_point_nominal &&
 103                     sample_point_error < best_sample_point_error) {
 104                         best_sample_point = sample_point;
 105                         best_sample_point_error = sample_point_error;
 106                         *tseg1_ptr = tseg1;
 107                         *tseg2_ptr = tseg2;
 108                 }
 109         }
 110
 111         if (sample_point_error_ptr)
 112                 *sample_point_error_ptr = best_sample_point_error;
 113
 114         return best_sample_point;
 115 }
 116
 117 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 118                               const struct can_bittiming_const *btc)
 119 {
 120         struct can_priv *priv = netdev_priv(dev);
 121         unsigned int bitrate;                   /* current bitrate */
 122         unsigned int bitrate_error;             /* difference between current and nominal value */
 123         unsigned int best_bitrate_error = UINT_MAX;
 124         unsigned int sample_point_error;        /* difference between current and nominal value */
 125         unsigned int best_sample_point_error = UINT_MAX;
 126         unsigned int sample_point_nominal;      /* nominal sample point */
 127         unsigned int best_tseg = 0;             /* current best value for tseg */
 128         unsigned int best_brp = 0;              /* current best value for brp */
 129         unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
 130         u64 v64;
 131
 132         /* Use CiA recommended sample points */
 133         if (bt->sample_point) {
 134                 sample_point_nominal = bt->sample_point;
 135         } else {
 136                 if (bt->bitrate > 800000)
 137                         sample_point_nominal = 750;
 138                 else if (bt->bitrate > 500000)
 139                         sample_point_nominal = 800;
 140                 else
 141                         sample_point_nominal = 875;
 142         }
 143
 144         /* tseg even = round down, odd = round up */
 145         for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
 146              tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
 147                 tsegall = CAN_SYNC_SEG + tseg / 2;
 148
 149                 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
 150                 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
 151
 152                 /* choose brp step which is possible in system */
 153                 brp = (brp / btc->brp_inc) * btc->brp_inc;
 154                 if (brp < btc->brp_min || brp > btc->brp_max)
 155                         continue;
 156
 157                 bitrate = priv->clock.freq / (brp * tsegall);
 158                 bitrate_error = abs(bt->bitrate - bitrate);
 159
 160                 /* tseg brp biterror */
 161                 if (bitrate_error > best_bitrate_error)
 162                         continue;
 163
 164                 /* reset sample point error if we have a better bitrate */
 165                 if (bitrate_error < best_bitrate_error)
 166                         best_sample_point_error = UINT_MAX;
 167
 168                 can_update_sample_point(btc, sample_point_nominal, tseg / 2,
 169                                         &tseg1, &tseg2, &sample_point_error);
 170                 if (sample_point_error > best_sample_point_error)
 171                         continue;
 172
 173                 best_sample_point_error = sample_point_error;
 174                 best_bitrate_error = bitrate_error;
 175                 best_tseg = tseg / 2;
 176                 best_brp = brp;
 177
 178                 if (bitrate_error == 0 && sample_point_error == 0)
 179                         break;
 180         }
 181
 182         if (best_bitrate_error) {
 183                 /* Error in one-tenth of a percent */
 184                 v64 = (u64)best_bitrate_error * 1000;
 185                 do_div(v64, bt->bitrate);
 186                 bitrate_error = (u32)v64;
 187                 if (bitrate_error > CAN_CALC_MAX_ERROR) {
 188                         netdev_err(dev,
 189                                    "bitrate error %d.%d%% too high\n",
 190                                    bitrate_error / 10, bitrate_error % 10);
 191                         return -EDOM;
 192                 }
 193                 netdev_warn(dev, "bitrate error %d.%d%%\n",
 194                             bitrate_error / 10, bitrate_error % 10);
 195         }
 196
 197         /* real sample point */
 198         bt->sample_point = can_update_sample_point(btc, sample_point_nominal,
 199                                                    best_tseg, &tseg1, &tseg2,
 200                                                    NULL);
 201
 202         v64 = (u64)best_brp * 1000 * 1000 * 1000;
 203         do_div(v64, priv->clock.freq);
 204         bt->tq = (u32)v64;
 205         bt->prop_seg = tseg1 / 2;
 206         bt->phase_seg1 = tseg1 - bt->prop_seg;
 207         bt->phase_seg2 = tseg2;
 208
 209         /* check for sjw user settings */
 210         if (!bt->sjw || !btc->sjw_max) {
 211                 bt->sjw = 1;
 212         } else {
 213                 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
 214                 if (bt->sjw > btc->sjw_max)
 215                         bt->sjw = btc->sjw_max;
 216                 /* bt->sjw must not be higher than tseg2 */
 217                 if (tseg2 < bt->sjw)
 218                         bt->sjw = tseg2;
 219         }
 220
 221         bt->brp = best_brp;
 222
 223         /* real bitrate */
 224         bt->bitrate = priv->clock.freq /
 225                 (bt->brp * (CAN_SYNC_SEG + tseg1 + tseg2));
 226
 227         return 0;
 228 }
 229 #else /* !CONFIG_CAN_CALC_BITTIMING */
 230 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 231                               const struct can_bittiming_const *btc)
 232 {
 233         netdev_err(dev, "bit-timing calculation not available\n");
 234         return -EINVAL;
 235 }
 236 #endif /* CONFIG_CAN_CALC_BITTIMING */
 237
 238 /* Checks the validity of the specified bit-timing parameters prop_seg,
 239  * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
 240  * prescaler value brp. You can find more information in the header
 241  * file linux/can/netlink.h.
 242  */
 243 static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
 244                                const struct can_bittiming_const *btc)
 245 {
 246         struct can_priv *priv = netdev_priv(dev);
 247         int tseg1, alltseg;
 248         u64 brp64;
 249
 250         tseg1 = bt->prop_seg + bt->phase_seg1;
 251         if (!bt->sjw)
 252                 bt->sjw = 1;
 253         if (bt->sjw > btc->sjw_max ||
 254             tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
 255             bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
 256                 return -ERANGE;
 257
 258         brp64 = (u64)priv->clock.freq * (u64)bt->tq;
 259         if (btc->brp_inc > 1)
 260                 do_div(brp64, btc->brp_inc);
 261         brp64 += 500000000UL - 1;
 262         do_div(brp64, 1000000000UL); /* the practicable BRP */
 263         if (btc->brp_inc > 1)
 264                 brp64 *= btc->brp_inc;
 265         bt->brp = (u32)brp64;
 266
 267         if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
 268                 return -EINVAL;
 269
 270         alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
 271         bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
 272         bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
 273
 274         return 0;
 275 }
 276
 277 /* Checks the validity of predefined bitrate settings */
 278 static int
 279 can_validate_bitrate(struct net_device *dev, struct can_bittiming *bt,
 280                      const u32 *bitrate_const,
 281                      const unsigned int bitrate_const_cnt)
 282 {
 283         struct can_priv *priv = netdev_priv(dev);
 284         unsigned int i;
 285
 286         for (i = 0; i < bitrate_const_cnt; i++) {
 287                 if (bt->bitrate == bitrate_const[i])
 288                         break;
 289         }
 290
 291         if (i >= priv->bitrate_const_cnt)
 292                 return -EINVAL;
 293
 294         return 0;
 295 }
 296
 297 static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
 298                              const struct can_bittiming_const *btc,
 299                              const u32 *bitrate_const,
 300                              const unsigned int bitrate_const_cnt)
 301 {
 302         int err;
 303
 304         /* Depending on the given can_bittiming parameter structure the CAN
 305          * timing parameters are calculated based on the provided bitrate OR
 306          * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
 307          * provided directly which are then checked and fixed up.
 308          */
 309         if (!bt->tq && bt->bitrate && btc)
 310                 err = can_calc_bittiming(dev, bt, btc);
 311         else if (bt->tq && !bt->bitrate && btc)
 312                 err = can_fixup_bittiming(dev, bt, btc);
 313         else if (!bt->tq && bt->bitrate && bitrate_const)
 314                 err = can_validate_bitrate(dev, bt, bitrate_const,
 315                                            bitrate_const_cnt);
 316         else
 317                 err = -EINVAL;
 318
 319         return err;
 320 }
 321
 322 static void can_update_state_error_stats(struct net_device *dev,
 323                                          enum can_state new_state)
 324 {
 325         struct can_priv *priv = netdev_priv(dev);
 326
 327         if (new_state <= priv->state)
 328                 return;
 329
 330         switch (new_state) {
 331         case CAN_STATE_ERROR_WARNING:
 332                 priv->can_stats.error_warning++;
 333                 break;
 334         case CAN_STATE_ERROR_PASSIVE:
 335                 priv->can_stats.error_passive++;
 336                 break;
 337         case CAN_STATE_BUS_OFF:
 338                 priv->can_stats.bus_off++;
 339                 break;
 340         default:
 341                 break;
 342         }
 343 }
 344
 345 static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
 346 {
 347         switch (state) {
 348         case CAN_STATE_ERROR_ACTIVE:
 349                 return CAN_ERR_CRTL_ACTIVE;
 350         case CAN_STATE_ERROR_WARNING:
 351                 return CAN_ERR_CRTL_TX_WARNING;
 352         case CAN_STATE_ERROR_PASSIVE:
 353                 return CAN_ERR_CRTL_TX_PASSIVE;
 354         default:
 355                 return 0;
 356         }
 357 }
 358
 359 static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
 360 {
 361         switch (state) {
 362         case CAN_STATE_ERROR_ACTIVE:
 363                 return CAN_ERR_CRTL_ACTIVE;
 364         case CAN_STATE_ERROR_WARNING:
 365                 return CAN_ERR_CRTL_RX_WARNING;
 366         case CAN_STATE_ERROR_PASSIVE:
 367                 return CAN_ERR_CRTL_RX_PASSIVE;
 368         default:
 369                 return 0;
 370         }
 371 }
 372
 373 static const char *can_get_state_str(const enum can_state state)
 374 {
 375         switch (state) {
 376         case CAN_STATE_ERROR_ACTIVE:
 377                 return "Error Active";
 378         case CAN_STATE_ERROR_WARNING:
 379                 return "Error Warning";
 380         case CAN_STATE_ERROR_PASSIVE:
 381                 return "Error Passive";
 382         case CAN_STATE_BUS_OFF:
 383                 return "Bus Off";
 384         case CAN_STATE_STOPPED:
 385                 return "Stopped";
 386         case CAN_STATE_SLEEPING:
 387                 return "Sleeping";
 388         default:
 389                 return "<unknown>";
 390         }
 391
 392         return "<unknown>";
 393 }
 394
 395 void can_change_state(struct net_device *dev, struct can_frame *cf,
 396                       enum can_state tx_state, enum can_state rx_state)
 397 {
 398         struct can_priv *priv = netdev_priv(dev);
 399         enum can_state new_state = max(tx_state, rx_state);
 400
 401         if (unlikely(new_state == priv->state)) {
 402                 netdev_warn(dev, "%s: oops, state did not change", __func__);
 403                 return;
 404         }
 405
 406         netdev_dbg(dev, "Controller changed from %s State (%d) into %s State (%d).\n",
 407                    can_get_state_str(priv->state), priv->state,
 408                    can_get_state_str(new_state), new_state);
 409
 410         can_update_state_error_stats(dev, new_state);
 411         priv->state = new_state;
 412
 413         if (!cf)
 414                 return;
 415
 416         if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
 417                 cf->can_id |= CAN_ERR_BUSOFF;
 418                 return;
 419         }
 420
 421         cf->can_id |= CAN_ERR_CRTL;
 422         cf->data[1] |= tx_state >= rx_state ?
 423                        can_tx_state_to_frame(dev, tx_state) : 0;
 424         cf->data[1] |= tx_state <= rx_state ?
 425                        can_rx_state_to_frame(dev, rx_state) : 0;
 426 }
 427 EXPORT_SYMBOL_GPL(can_change_state);
 428
 429 /* Local echo of CAN messages
 430  *
 431  * CAN network devices *should* support a local echo functionality
 432  * (see Documentation/networking/can.rst). To test the handling of CAN
 433  * interfaces that do not support the local echo both driver types are
 434  * implemented. In the case that the driver does not support the echo
 435  * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
 436  * to perform the echo as a fallback solution.
 437  */
 438 static void can_flush_echo_skb(struct net_device *dev)
 439 {
 440         struct can_priv *priv = netdev_priv(dev);
 441         struct net_device_stats *stats = &dev->stats;
 442         int i;
 443
 444         for (i = 0; i < priv->echo_skb_max; i++) {
 445                 if (priv->echo_skb[i]) {
 446                         kfree_skb(priv->echo_skb[i]);
 447                         priv->echo_skb[i] = NULL;
 448                         stats->tx_dropped++;
 449                         stats->tx_aborted_errors++;
 450                 }
 451         }
 452 }
 453
 454 /* Put the skb on the stack to be looped backed locally lateron
 455  *
 456  * The function is typically called in the start_xmit function
 457  * of the device driver. The driver must protect access to
 458  * priv->echo_skb, if necessary.
 459  */
 460 int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 461                      unsigned int idx)
 462 {
 463         struct can_priv *priv = netdev_priv(dev);
 464
 465         BUG_ON(idx >= priv->echo_skb_max);
 466
 467         /* check flag whether this packet has to be looped back */
 468         if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
 469             (skb->protocol != htons(ETH_P_CAN) &&
 470              skb->protocol != htons(ETH_P_CANFD))) {
 471                 kfree_skb(skb);
 472                 return 0;
 473         }
 474
 475         if (!priv->echo_skb[idx]) {
 476                 skb = can_create_echo_skb(skb);
 477                 if (!skb)
 478                         return -ENOMEM;
 479
 480                 /* make settings for echo to reduce code in irq context */
 481                 skb->pkt_type = PACKET_BROADCAST;
 482                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 483                 skb->dev = dev;
 484
 485                 /* save this skb for tx interrupt echo handling */
 486                 priv->echo_skb[idx] = skb;
 487         } else {
 488                 /* locking problem with netif_stop_queue() ?? */
 489                 netdev_err(dev, "%s: BUG! echo_skb %d is occupied!\n", __func__, idx);
 490                 kfree_skb(skb);
 491                 return -EBUSY;
 492         }
 493
 494         return 0;
 495 }
 496 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 497
 498 struct sk_buff *
 499 __can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
 500 {
 501         struct can_priv *priv = netdev_priv(dev);
 502
 503         if (idx >= priv->echo_skb_max) {
 504                 netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
 505                            __func__, idx, priv->echo_skb_max);
 506                 return NULL;
 507         }
 508
 509         if (priv->echo_skb[idx]) {
 510                 /* Using "struct canfd_frame::len" for the frame
 511                  * length is supported on both CAN and CANFD frames.
 512                  */
 513                 struct sk_buff *skb = priv->echo_skb[idx];
 514                 struct canfd_frame *cf = (struct canfd_frame *)skb->data;
 515                 u8 len = cf->len;
 516
 517                 *len_ptr = len;
 518                 priv->echo_skb[idx] = NULL;
 519
 520                 return skb;
 521         }
 522
 523         return NULL;
 524 }
 525
 526 /* Get the skb from the stack and loop it back locally
 527  *
 528  * The function is typically called when the TX done interrupt
 529  * is handled in the device driver. The driver must protect
 530  * access to priv->echo_skb, if necessary.
 531  */
 532 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 533 {
 534         struct sk_buff *skb;
 535         u8 len;
 536
 537         skb = __can_get_echo_skb(dev, idx, &len);
 538         if (!skb)
 539                 return 0;
 540
 541         netif_rx(skb);
 542
 543         return len;
 544 }
 545 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 546
 547 /* Remove the skb from the stack and free it.
 548  *
 549  * The function is typically called when TX failed.
 550  */
 551 void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 552 {
 553         struct can_priv *priv = netdev_priv(dev);
 554
 555         BUG_ON(idx >= priv->echo_skb_max);
 556
 557         if (priv->echo_skb[idx]) {
 558                 dev_kfree_skb_any(priv->echo_skb[idx]);
 559                 priv->echo_skb[idx] = NULL;
 560         }
 561 }
 562 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 563
 564 /* CAN device restart for bus-off recovery */
 565 static void can_restart(struct net_device *dev)
 566 {
 567         struct can_priv *priv = netdev_priv(dev);
 568         struct net_device_stats *stats = &dev->stats;
 569         struct sk_buff *skb;
 570         struct can_frame *cf;
 571         int err;
 572
 573         BUG_ON(netif_carrier_ok(dev));
 574
 575         /* No synchronization needed because the device is bus-off and
 576          * no messages can come in or go out.
 577          */
 578         can_flush_echo_skb(dev);
 579
 580         /* send restart message upstream */
 581         skb = alloc_can_err_skb(dev, &cf);
 582         if (!skb)
 583                 goto restart;
 584
 585         cf->can_id |= CAN_ERR_RESTARTED;
 586
 587         netif_rx(skb);
 588
 589         stats->rx_packets++;
 590         stats->rx_bytes += cf->can_dlc;
 591
 592 restart:
 593         netdev_dbg(dev, "restarted\n");
 594         priv->can_stats.restarts++;
 595
 596         /* Now restart the device */
 597         err = priv->do_set_mode(dev, CAN_MODE_START);
 598
 599         netif_carrier_on(dev);
 600         if (err)
 601                 netdev_err(dev, "Error %d during restart", err);
 602 }
 603
 604 static void can_restart_work(struct work_struct *work)
 605 {
 606         struct delayed_work *dwork = to_delayed_work(work);
 607         struct can_priv *priv = container_of(dwork, struct can_priv,
 608                                              restart_work);
 609
 610         can_restart(priv->dev);
 611 }
 612
 613 int can_restart_now(struct net_device *dev)
 614 {
 615         struct can_priv *priv = netdev_priv(dev);
 616
 617         /* A manual restart is only permitted if automatic restart is
 618          * disabled and the device is in the bus-off state
 619          */
 620         if (priv->restart_ms)
 621                 return -EINVAL;
 622         if (priv->state != CAN_STATE_BUS_OFF)
 623                 return -EBUSY;
 624
 625         cancel_delayed_work_sync(&priv->restart_work);
 626         can_restart(dev);
 627
 628         return 0;
 629 }
 630
 631 /* CAN bus-off
 632  *
 633  * This functions should be called when the device goes bus-off to
 634  * tell the netif layer that no more packets can be sent or received.
 635  * If enabled, a timer is started to trigger bus-off recovery.
 636  */
 637 void can_bus_off(struct net_device *dev)
 638 {
 639         struct can_priv *priv = netdev_priv(dev);
 640
 641         if (priv->restart_ms)
 642                 netdev_info(dev, "bus-off, scheduling restart in %d ms\n",
 643                             priv->restart_ms);
 644         else
 645                 netdev_info(dev, "bus-off\n");
 646
 647         netif_carrier_off(dev);
 648
 649         if (priv->restart_ms)
 650                 schedule_delayed_work(&priv->restart_work,
 651                                       msecs_to_jiffies(priv->restart_ms));
 652 }
 653 EXPORT_SYMBOL_GPL(can_bus_off);
 654
 655 static void can_setup(struct net_device *dev)
 656 {
 657         dev->type = ARPHRD_CAN;
 658         dev->mtu = CAN_MTU;
 659         dev->hard_header_len = 0;
 660         dev->addr_len = 0;
 661         dev->tx_queue_len = 10;
 662
 663         /* New-style flags. */
 664         dev->flags = IFF_NOARP;
 665         dev->features = NETIF_F_HW_CSUM;
 666 }
 667
 668 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 669 {
 670         struct sk_buff *skb;
 671
 672         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 673                                sizeof(struct can_frame));
 674         if (unlikely(!skb))
 675                 return NULL;
 676
 677         skb->protocol = htons(ETH_P_CAN);
 678         skb->pkt_type = PACKET_BROADCAST;
 679         skb->ip_summed = CHECKSUM_UNNECESSARY;
 680
 681         skb_reset_mac_header(skb);
 682         skb_reset_network_header(skb);
 683         skb_reset_transport_header(skb);
 684
 685         can_skb_reserve(skb);
 686         can_skb_prv(skb)->ifindex = dev->ifindex;
 687         can_skb_prv(skb)->skbcnt = 0;
 688
 689         *cf = skb_put_zero(skb, sizeof(struct can_frame));
 690
 691         return skb;
 692 }
 693 EXPORT_SYMBOL_GPL(alloc_can_skb);
 694
 695 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 696                                 struct canfd_frame **cfd)
 697 {
 698         struct sk_buff *skb;
 699
 700         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 701                                sizeof(struct canfd_frame));
 702         if (unlikely(!skb))
 703                 return NULL;
 704
 705         skb->protocol = htons(ETH_P_CANFD);
 706         skb->pkt_type = PACKET_BROADCAST;
 707         skb->ip_summed = CHECKSUM_UNNECESSARY;
 708
 709         skb_reset_mac_header(skb);
 710         skb_reset_network_header(skb);
 711         skb_reset_transport_header(skb);
 712
 713         can_skb_reserve(skb);
 714         can_skb_prv(skb)->ifindex = dev->ifindex;
 715         can_skb_prv(skb)->skbcnt = 0;
 716
 717         *cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
 718
 719         return skb;
 720 }
 721 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 722
 723 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 724 {
 725         struct sk_buff *skb;
 726
 727         skb = alloc_can_skb(dev, cf);
 728         if (unlikely(!skb))
 729                 return NULL;
 730
 731         (*cf)->can_id = CAN_ERR_FLAG;
 732         (*cf)->can_dlc = CAN_ERR_DLC;
 733
 734         return skb;
 735 }
 736 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 737
 738 /* Allocate and setup space for the CAN network device */
 739 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
 740                                     unsigned int txqs, unsigned int rxqs)
 741 {
 742         struct net_device *dev;
 743         struct can_priv *priv;
 744         int size;
 745
 746         /* We put the driver's priv, the CAN mid layer priv and the
 747          * echo skb into the netdevice's priv. The memory layout for
 748          * the netdev_priv is like this:
 749          *
 750          * +-------------------------+
 751          * | driver's priv           |
 752          * +-------------------------+
 753          * | struct can_ml_priv      |
 754          * +-------------------------+
 755          * | array of struct sk_buff |
 756          * +-------------------------+
 757          */
 758
 759         size = ALIGN(sizeof_priv, NETDEV_ALIGN) + sizeof(struct can_ml_priv);
 760
 761         if (echo_skb_max)
 762                 size = ALIGN(size, sizeof(struct sk_buff *)) +
 763                         echo_skb_max * sizeof(struct sk_buff *);
 764
 765         dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup,
 766                                txqs, rxqs);
 767         if (!dev)
 768                 return NULL;
 769
 770         priv = netdev_priv(dev);
 771         priv->dev = dev;
 772
 773         dev->ml_priv = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN);
 774
 775         if (echo_skb_max) {
 776                 priv->echo_skb_max = echo_skb_max;
 777                 priv->echo_skb = (void *)priv +
 778                         (size - echo_skb_max * sizeof(struct sk_buff *));
 779         }
 780
 781         priv->state = CAN_STATE_STOPPED;
 782
 783         INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
 784
 785         return dev;
 786 }
 787 EXPORT_SYMBOL_GPL(alloc_candev_mqs);
 788
 789 /* Free space of the CAN network device */
 790 void free_candev(struct net_device *dev)
 791 {
 792         free_netdev(dev);
 793 }
 794 EXPORT_SYMBOL_GPL(free_candev);
 795
 796 /* changing MTU and control mode for CAN/CANFD devices */
 797 int can_change_mtu(struct net_device *dev, int new_mtu)
 798 {
 799         struct can_priv *priv = netdev_priv(dev);
 800
 801         /* Do not allow changing the MTU while running */
 802         if (dev->flags & IFF_UP)
 803                 return -EBUSY;
 804
 805         /* allow change of MTU according to the CANFD ability of the device */
 806         switch (new_mtu) {
 807         case CAN_MTU:
 808                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 809                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 810                         return -EINVAL;
 811
 812                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 813                 break;
 814
 815         case CANFD_MTU:
 816                 /* check for potential CANFD ability */
 817                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 818                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 819                         return -EINVAL;
 820
 821                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 822                 break;
 823
 824         default:
 825                 return -EINVAL;
 826         }
 827
 828         dev->mtu = new_mtu;
 829         return 0;
 830 }
 831 EXPORT_SYMBOL_GPL(can_change_mtu);
 832
 833 /* Common open function when the device gets opened.
 834  *
 835  * This function should be called in the open function of the device
 836  * driver.
 837  */
 838 int open_candev(struct net_device *dev)
 839 {
 840         struct can_priv *priv = netdev_priv(dev);
 841
 842         if (!priv->bittiming.bitrate) {
 843                 netdev_err(dev, "bit-timing not yet defined\n");
 844                 return -EINVAL;
 845         }
 846
 847         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 848         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 849             (!priv->data_bittiming.bitrate ||
 850              priv->data_bittiming.bitrate < priv->bittiming.bitrate)) {
 851                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 852                 return -EINVAL;
 853         }
 854
 855         /* Switch carrier on if device was stopped while in bus-off state */
 856         if (!netif_carrier_ok(dev))
 857                 netif_carrier_on(dev);
 858
 859         return 0;
 860 }
 861 EXPORT_SYMBOL_GPL(open_candev);
 862
 863 #ifdef CONFIG_OF
 864 /* Common function that can be used to understand the limitation of
 865  * a transceiver when it provides no means to determine these limitations
 866  * at runtime.
 867  */
 868 void of_can_transceiver(struct net_device *dev)
 869 {
 870         struct device_node *dn;
 871         struct can_priv *priv = netdev_priv(dev);
 872         struct device_node *np = dev->dev.parent->of_node;
 873         int ret;
 874
 875         dn = of_get_child_by_name(np, "can-transceiver");
 876         if (!dn)
 877                 return;
 878
 879         ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max);
 880         of_node_put(dn);
 881         if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
 882                 netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
 883 }
 884 EXPORT_SYMBOL_GPL(of_can_transceiver);
 885 #endif
 886
 887 /* Common close function for cleanup before the device gets closed.
 888  *
 889  * This function should be called in the close function of the device
 890  * driver.
 891  */
 892 void close_candev(struct net_device *dev)
 893 {
 894         struct can_priv *priv = netdev_priv(dev);
 895
 896         cancel_delayed_work_sync(&priv->restart_work);
 897         can_flush_echo_skb(dev);
 898 }
 899 EXPORT_SYMBOL_GPL(close_candev);
 900
 901 /* CAN netlink interface */
 902 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 903         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 904         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 905         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 906         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 907         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 908         [IFLA_CAN_BITTIMING_CONST]
 909                                 = { .len = sizeof(struct can_bittiming_const) },
 910         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 911         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 912         [IFLA_CAN_DATA_BITTIMING]
 913                                 = { .len = sizeof(struct can_bittiming) },
 914         [IFLA_CAN_DATA_BITTIMING_CONST]
 915                                 = { .len = sizeof(struct can_bittiming_const) },
 916         [IFLA_CAN_TERMINATION]  = { .type = NLA_U16 },
 917 };
 918
 919 static int can_validate(struct nlattr *tb[], struct nlattr *data[],
 920                         struct netlink_ext_ack *extack)
 921 {
 922         bool is_can_fd = false;
 923
 924         /* Make sure that valid CAN FD configurations always consist of
 925          * - nominal/arbitration bittiming
 926          * - data bittiming
 927          * - control mode with CAN_CTRLMODE_FD set
 928          */
 929
 930         if (!data)
 931                 return 0;
 932
 933         if (data[IFLA_CAN_CTRLMODE]) {
 934                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 935
 936                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 937         }
 938
 939         if (is_can_fd) {
 940                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 941                         return -EOPNOTSUPP;
 942         }
 943
 944         if (data[IFLA_CAN_DATA_BITTIMING]) {
 945                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 946                         return -EOPNOTSUPP;
 947         }
 948
 949         return 0;
 950 }
 951
 952 static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 953                           struct nlattr *data[],
 954                           struct netlink_ext_ack *extack)
 955 {
 956         struct can_priv *priv = netdev_priv(dev);
 957         int err;
 958
 959         /* We need synchronization with dev->stop() */
 960         ASSERT_RTNL();
 961
 962         if (data[IFLA_CAN_BITTIMING]) {
 963                 struct can_bittiming bt;
 964
 965                 /* Do not allow changing bittiming while running */
 966                 if (dev->flags & IFF_UP)
 967                         return -EBUSY;
 968
 969                 /* Calculate bittiming parameters based on
 970                  * bittiming_const if set, otherwise pass bitrate
 971                  * directly via do_set_bitrate(). Bail out if neither
 972                  * is given.
 973                  */
 974                 if (!priv->bittiming_const && !priv->do_set_bittiming)
 975                         return -EOPNOTSUPP;
 976
 977                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 978                 err = can_get_bittiming(dev, &bt,
 979                                         priv->bittiming_const,
 980                                         priv->bitrate_const,
 981                                         priv->bitrate_const_cnt);
 982                 if (err)
 983                         return err;
 984
 985                 if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) {
 986                         netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n",
 987                                    priv->bitrate_max);
 988                         return -EINVAL;
 989                 }
 990
 991                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 992
 993                 if (priv->do_set_bittiming) {
 994                         /* Finally, set the bit-timing registers */
 995                         err = priv->do_set_bittiming(dev);
 996                         if (err)
 997                                 return err;
 998                 }
 999         }
1000
1001         if (data[IFLA_CAN_CTRLMODE]) {
1002                 struct can_ctrlmode *cm;
1003                 u32 ctrlstatic;
1004                 u32 maskedflags;
1005
1006                 /* Do not allow changing controller mode while running */
1007                 if (dev->flags & IFF_UP)
1008                         return -EBUSY;
1009                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
1010                 ctrlstatic = priv->ctrlmode_static;
1011                 maskedflags = cm->flags & cm->mask;
1012
1013                 /* check whether provided bits are allowed to be passed */
1014                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
1015                         return -EOPNOTSUPP;
1016
1017                 /* do not check for static fd-non-iso if 'fd' is disabled */
1018                 if (!(maskedflags & CAN_CTRLMODE_FD))
1019                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
1020
1021                 /* make sure static options are provided by configuration */
1022                 if ((maskedflags & ctrlstatic) != ctrlstatic)
1023                         return -EOPNOTSUPP;
1024
1025                 /* clear bits to be modified and copy the flag values */
1026                 priv->ctrlmode &= ~cm->mask;
1027                 priv->ctrlmode |= maskedflags;
1028
1029                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
1030                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
1031                         dev->mtu = CANFD_MTU;
1032                 else
1033                         dev->mtu = CAN_MTU;
1034         }
1035
1036         if (data[IFLA_CAN_RESTART_MS]) {
1037                 /* Do not allow changing restart delay while running */
1038                 if (dev->flags & IFF_UP)
1039                         return -EBUSY;
1040                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
1041         }
1042
1043         if (data[IFLA_CAN_RESTART]) {
1044                 /* Do not allow a restart while not running */
1045                 if (!(dev->flags & IFF_UP))
1046                         return -EINVAL;
1047                 err = can_restart_now(dev);
1048                 if (err)
1049                         return err;
1050         }
1051
1052         if (data[IFLA_CAN_DATA_BITTIMING]) {
1053                 struct can_bittiming dbt;
1054
1055                 /* Do not allow changing bittiming while running */
1056                 if (dev->flags & IFF_UP)
1057                         return -EBUSY;
1058
1059                 /* Calculate bittiming parameters based on
1060                  * data_bittiming_const if set, otherwise pass bitrate
1061                  * directly via do_set_bitrate(). Bail out if neither
1062                  * is given.
1063                  */
1064                 if (!priv->data_bittiming_const && !priv->do_set_data_bittiming)
1065                         return -EOPNOTSUPP;
1066
1067                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
1068                        sizeof(dbt));
1069                 err = can_get_bittiming(dev, &dbt,
1070                                         priv->data_bittiming_const,
1071                                         priv->data_bitrate_const,
1072                                         priv->data_bitrate_const_cnt);
1073                 if (err)
1074                         return err;
1075
1076                 if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
1077                         netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
1078                                    priv->bitrate_max);
1079                         return -EINVAL;
1080                 }
1081
1082                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
1083
1084                 if (priv->do_set_data_bittiming) {
1085                         /* Finally, set the bit-timing registers */
1086                         err = priv->do_set_data_bittiming(dev);
1087                         if (err)
1088                                 return err;
1089                 }
1090         }
1091
1092         if (data[IFLA_CAN_TERMINATION]) {
1093                 const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]);
1094                 const unsigned int num_term = priv->termination_const_cnt;
1095                 unsigned int i;
1096
1097                 if (!priv->do_set_termination)
1098                         return -EOPNOTSUPP;
1099
1100                 /* check whether given value is supported by the interface */
1101                 for (i = 0; i < num_term; i++) {
1102                         if (termval == priv->termination_const[i])
1103                                 break;
1104                 }
1105                 if (i >= num_term)
1106                         return -EINVAL;
1107
1108                 /* Finally, set the termination value */
1109                 err = priv->do_set_termination(dev, termval);
1110                 if (err)
1111                         return err;
1112
1113                 priv->termination = termval;
1114         }
1115
1116         return 0;
1117 }
1118
1119 static size_t can_get_size(const struct net_device *dev)
1120 {
1121         struct can_priv *priv = netdev_priv(dev);
1122         size_t size = 0;
1123
1124         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
1125                 size += nla_total_size(sizeof(struct can_bittiming));
1126         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
1127                 size += nla_total_size(sizeof(struct can_bittiming_const));
1128         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
1129         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
1130         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
1131         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
1132         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
1133                 size += nla_total_size(sizeof(struct can_berr_counter));
1134         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
1135                 size += nla_total_size(sizeof(struct can_bittiming));
1136         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
1137                 size += nla_total_size(sizeof(struct can_bittiming_const));
1138         if (priv->termination_const) {
1139                 size += nla_total_size(sizeof(priv->termination));              /* IFLA_CAN_TERMINATION */
1140                 size += nla_total_size(sizeof(*priv->termination_const) *       /* IFLA_CAN_TERMINATION_CONST */
1141                                        priv->termination_const_cnt);
1142         }
1143         if (priv->bitrate_const)                                /* IFLA_CAN_BITRATE_CONST */
1144                 size += nla_total_size(sizeof(*priv->bitrate_const) *
1145                                        priv->bitrate_const_cnt);
1146         if (priv->data_bitrate_const)                           /* IFLA_CAN_DATA_BITRATE_CONST */
1147                 size += nla_total_size(sizeof(*priv->data_bitrate_const) *
1148                                        priv->data_bitrate_const_cnt);
1149         size += sizeof(priv->bitrate_max);                      /* IFLA_CAN_BITRATE_MAX */
1150
1151         return size;
1152 }
1153
1154 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
1155 {
1156         struct can_priv *priv = netdev_priv(dev);
1157         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
1158         struct can_berr_counter bec;
1159         enum can_state state = priv->state;
1160
1161         if (priv->do_get_state)
1162                 priv->do_get_state(dev, &state);
1163
1164         if ((priv->bittiming.bitrate &&
1165              nla_put(skb, IFLA_CAN_BITTIMING,
1166                      sizeof(priv->bittiming), &priv->bittiming)) ||
1167
1168             (priv->bittiming_const &&
1169              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1170                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1171
1172             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1173             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1174             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1175             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1176
1177             (priv->do_get_berr_counter &&
1178              !priv->do_get_berr_counter(dev, &bec) &&
1179              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1180
1181             (priv->data_bittiming.bitrate &&
1182              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1183                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1184
1185             (priv->data_bittiming_const &&
1186              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1187                      sizeof(*priv->data_bittiming_const),
1188                      priv->data_bittiming_const)) ||
1189
1190             (priv->termination_const &&
1191              (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||
1192               nla_put(skb, IFLA_CAN_TERMINATION_CONST,
1193                       sizeof(*priv->termination_const) *
1194                       priv->termination_const_cnt,
1195                       priv->termination_const))) ||
1196
1197             (priv->bitrate_const &&
1198              nla_put(skb, IFLA_CAN_BITRATE_CONST,
1199                      sizeof(*priv->bitrate_const) *
1200                      priv->bitrate_const_cnt,
1201                      priv->bitrate_const)) ||
1202
1203             (priv->data_bitrate_const &&
1204              nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
1205                      sizeof(*priv->data_bitrate_const) *
1206                      priv->data_bitrate_const_cnt,
1207                      priv->data_bitrate_const)) ||
1208
1209             (nla_put(skb, IFLA_CAN_BITRATE_MAX,
1210                      sizeof(priv->bitrate_max),
1211                      &priv->bitrate_max))
1212             )
1213
1214                 return -EMSGSIZE;
1215
1216         return 0;
1217 }
1218
1219 static size_t can_get_xstats_size(const struct net_device *dev)
1220 {
1221         return sizeof(struct can_device_stats);
1222 }
1223
1224 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1225 {
1226         struct can_priv *priv = netdev_priv(dev);
1227
1228         if (nla_put(skb, IFLA_INFO_XSTATS,
1229                     sizeof(priv->can_stats), &priv->can_stats))
1230                 goto nla_put_failure;
1231         return 0;
1232
1233 nla_put_failure:
1234         return -EMSGSIZE;
1235 }
1236
1237 static int can_newlink(struct net *src_net, struct net_device *dev,
1238                        struct nlattr *tb[], struct nlattr *data[],
1239                        struct netlink_ext_ack *extack)
1240 {
1241         return -EOPNOTSUPP;
1242 }
1243
1244 static void can_dellink(struct net_device *dev, struct list_head *head)
1245 {
1246 }
1247
1248 static struct rtnl_link_ops can_link_ops __read_mostly = {
1249         .kind           = "can",
1250         .maxtype        = IFLA_CAN_MAX,
1251         .policy         = can_policy,
1252         .setup          = can_setup,
1253         .validate       = can_validate,
1254         .newlink        = can_newlink,
1255         .changelink     = can_changelink,
1256         .dellink        = can_dellink,
1257         .get_size       = can_get_size,
1258         .fill_info      = can_fill_info,
1259         .get_xstats_size = can_get_xstats_size,
1260         .fill_xstats    = can_fill_xstats,
1261 };
1262
1263 /* Register the CAN network device */
1264 int register_candev(struct net_device *dev)
1265 {
1266         struct can_priv *priv = netdev_priv(dev);
1267
1268         /* Ensure termination_const, termination_const_cnt and
1269          * do_set_termination consistency. All must be either set or
1270          * unset.
1271          */
1272         if ((!priv->termination_const != !priv->termination_const_cnt) ||
1273             (!priv->termination_const != !priv->do_set_termination))
1274                 return -EINVAL;
1275
1276         if (!priv->bitrate_const != !priv->bitrate_const_cnt)
1277                 return -EINVAL;
1278
1279         if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
1280                 return -EINVAL;
1281
1282         dev->rtnl_link_ops = &can_link_ops;
1283         netif_carrier_off(dev);
1284
1285         return register_netdev(dev);
1286 }
1287 EXPORT_SYMBOL_GPL(register_candev);
1288
1289 /* Unregister the CAN network device */
1290 void unregister_candev(struct net_device *dev)
1291 {
1292         unregister_netdev(dev);
1293 }
1294 EXPORT_SYMBOL_GPL(unregister_candev);
1295
1296 /* Test if a network device is a candev based device
1297  * and return the can_priv* if so.
1298  */
1299 struct can_priv *safe_candev_priv(struct net_device *dev)
1300 {
1301         if (dev->type != ARPHRD_CAN || dev->rtnl_link_ops != &can_link_ops)
1302                 return NULL;
1303
1304         return netdev_priv(dev);
1305 }
1306 EXPORT_SYMBOL_GPL(safe_candev_priv);
1307
1308 static __init int can_dev_init(void)
1309 {
1310         int err;
1311
1312         can_led_notifier_init();
1313
1314         err = rtnl_link_register(&can_link_ops);
1315         if (!err)
1316                 pr_info(MOD_DESC "\n");
1317
1318         return err;
1319 }
1320 module_init(can_dev_init);
1321
1322 static __exit void can_dev_exit(void)
1323 {
1324         rtnl_link_unregister(&can_link_ops);
1325
1326         can_led_notifier_exit();
1327 }
1328 module_exit(can_dev_exit);
1329
1330 MODULE_ALIAS_RTNL_LINK("can");