drivers/net/can/dev/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
  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: pisa@cmp.felk.cvut.cz
  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
 516                 /* get the real payload length for netdev statistics */
 517                 if (cf->can_id & CAN_RTR_FLAG)
 518                         *len_ptr = 0;
 519                 else
 520                         *len_ptr = cf->len;
 521
 522                 priv->echo_skb[idx] = NULL;
 523
 524                 return skb;
 525         }
 526
 527         return NULL;
 528 }
 529
 530 /* Get the skb from the stack and loop it back locally
 531  *
 532  * The function is typically called when the TX done interrupt
 533  * is handled in the device driver. The driver must protect
 534  * access to priv->echo_skb, if necessary.
 535  */
 536 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 537 {
 538         struct sk_buff *skb;
 539         u8 len;
 540
 541         skb = __can_get_echo_skb(dev, idx, &len);
 542         if (!skb)
 543                 return 0;
 544
 545         skb_get(skb);
 546         if (netif_rx(skb) == NET_RX_SUCCESS)
 547                 dev_consume_skb_any(skb);
 548         else
 549                 dev_kfree_skb_any(skb);
 550
 551         return len;
 552 }
 553 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 554
 555 /* Remove the skb from the stack and free it.
 556  *
 557  * The function is typically called when TX failed.
 558  */
 559 void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 560 {
 561         struct can_priv *priv = netdev_priv(dev);
 562
 563         BUG_ON(idx >= priv->echo_skb_max);
 564
 565         if (priv->echo_skb[idx]) {
 566                 dev_kfree_skb_any(priv->echo_skb[idx]);
 567                 priv->echo_skb[idx] = NULL;
 568         }
 569 }
 570 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 571
 572 /* CAN device restart for bus-off recovery */
 573 static void can_restart(struct net_device *dev)
 574 {
 575         struct can_priv *priv = netdev_priv(dev);
 576         struct net_device_stats *stats = &dev->stats;
 577         struct sk_buff *skb;
 578         struct can_frame *cf;
 579         int err;
 580
 581         BUG_ON(netif_carrier_ok(dev));
 582
 583         /* No synchronization needed because the device is bus-off and
 584          * no messages can come in or go out.
 585          */
 586         can_flush_echo_skb(dev);
 587
 588         /* send restart message upstream */
 589         skb = alloc_can_err_skb(dev, &cf);
 590         if (!skb)
 591                 goto restart;
 592
 593         cf->can_id |= CAN_ERR_RESTARTED;
 594
 595         stats->rx_packets++;
 596         stats->rx_bytes += cf->can_dlc;
 597
 598         netif_rx_ni(skb);
 599
 600 restart:
 601         netdev_dbg(dev, "restarted\n");
 602         priv->can_stats.restarts++;
 603
 604         /* Now restart the device */
 605         err = priv->do_set_mode(dev, CAN_MODE_START);
 606
 607         netif_carrier_on(dev);
 608         if (err)
 609                 netdev_err(dev, "Error %d during restart", err);
 610 }
 611
 612 static void can_restart_work(struct work_struct *work)
 613 {
 614         struct delayed_work *dwork = to_delayed_work(work);
 615         struct can_priv *priv = container_of(dwork, struct can_priv,
 616                                              restart_work);
 617
 618         can_restart(priv->dev);
 619 }
 620
 621 int can_restart_now(struct net_device *dev)
 622 {
 623         struct can_priv *priv = netdev_priv(dev);
 624
 625         /* A manual restart is only permitted if automatic restart is
 626          * disabled and the device is in the bus-off state
 627          */
 628         if (priv->restart_ms)
 629                 return -EINVAL;
 630         if (priv->state != CAN_STATE_BUS_OFF)
 631                 return -EBUSY;
 632
 633         cancel_delayed_work_sync(&priv->restart_work);
 634         can_restart(dev);
 635
 636         return 0;
 637 }
 638
 639 /* CAN bus-off
 640  *
 641  * This functions should be called when the device goes bus-off to
 642  * tell the netif layer that no more packets can be sent or received.
 643  * If enabled, a timer is started to trigger bus-off recovery.
 644  */
 645 void can_bus_off(struct net_device *dev)
 646 {
 647         struct can_priv *priv = netdev_priv(dev);
 648
 649         if (priv->restart_ms)
 650                 netdev_info(dev, "bus-off, scheduling restart in %d ms\n",
 651                             priv->restart_ms);
 652         else
 653                 netdev_info(dev, "bus-off\n");
 654
 655         netif_carrier_off(dev);
 656
 657         if (priv->restart_ms)
 658                 schedule_delayed_work(&priv->restart_work,
 659                                       msecs_to_jiffies(priv->restart_ms));
 660 }
 661 EXPORT_SYMBOL_GPL(can_bus_off);
 662
 663 static void can_setup(struct net_device *dev)
 664 {
 665         dev->type = ARPHRD_CAN;
 666         dev->mtu = CAN_MTU;
 667         dev->hard_header_len = 0;
 668         dev->addr_len = 0;
 669         dev->tx_queue_len = 10;
 670
 671         /* New-style flags. */
 672         dev->flags = IFF_NOARP;
 673         dev->features = NETIF_F_HW_CSUM;
 674 }
 675
 676 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 677 {
 678         struct sk_buff *skb;
 679
 680         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 681                                sizeof(struct can_frame));
 682         if (unlikely(!skb))
 683                 return NULL;
 684
 685         skb->protocol = htons(ETH_P_CAN);
 686         skb->pkt_type = PACKET_BROADCAST;
 687         skb->ip_summed = CHECKSUM_UNNECESSARY;
 688
 689         skb_reset_mac_header(skb);
 690         skb_reset_network_header(skb);
 691         skb_reset_transport_header(skb);
 692
 693         can_skb_reserve(skb);
 694         can_skb_prv(skb)->ifindex = dev->ifindex;
 695         can_skb_prv(skb)->skbcnt = 0;
 696
 697         *cf = skb_put_zero(skb, sizeof(struct can_frame));
 698
 699         return skb;
 700 }
 701 EXPORT_SYMBOL_GPL(alloc_can_skb);
 702
 703 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 704                                 struct canfd_frame **cfd)
 705 {
 706         struct sk_buff *skb;
 707
 708         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 709                                sizeof(struct canfd_frame));
 710         if (unlikely(!skb))
 711                 return NULL;
 712
 713         skb->protocol = htons(ETH_P_CANFD);
 714         skb->pkt_type = PACKET_BROADCAST;
 715         skb->ip_summed = CHECKSUM_UNNECESSARY;
 716
 717         skb_reset_mac_header(skb);
 718         skb_reset_network_header(skb);
 719         skb_reset_transport_header(skb);
 720
 721         can_skb_reserve(skb);
 722         can_skb_prv(skb)->ifindex = dev->ifindex;
 723         can_skb_prv(skb)->skbcnt = 0;
 724
 725         *cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
 726
 727         return skb;
 728 }
 729 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 730
 731 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 732 {
 733         struct sk_buff *skb;
 734
 735         skb = alloc_can_skb(dev, cf);
 736         if (unlikely(!skb))
 737                 return NULL;
 738
 739         (*cf)->can_id = CAN_ERR_FLAG;
 740         (*cf)->can_dlc = CAN_ERR_DLC;
 741
 742         return skb;
 743 }
 744 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 745
 746 /* Allocate and setup space for the CAN network device */
 747 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
 748                                     unsigned int txqs, unsigned int rxqs)
 749 {
 750         struct can_ml_priv *can_ml;
 751         struct net_device *dev;
 752         struct can_priv *priv;
 753         int size;
 754
 755         /* We put the driver's priv, the CAN mid layer priv and the
 756          * echo skb into the netdevice's priv. The memory layout for
 757          * the netdev_priv is like this:
 758          *
 759          * +-------------------------+
 760          * | driver's priv           |
 761          * +-------------------------+
 762          * | struct can_ml_priv      |
 763          * +-------------------------+
 764          * | array of struct sk_buff |
 765          * +-------------------------+
 766          */
 767
 768         size = ALIGN(sizeof_priv, NETDEV_ALIGN) + sizeof(struct can_ml_priv);
 769
 770         if (echo_skb_max)
 771                 size = ALIGN(size, sizeof(struct sk_buff *)) +
 772                         echo_skb_max * sizeof(struct sk_buff *);
 773
 774         dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup,
 775                                txqs, rxqs);
 776         if (!dev)
 777                 return NULL;
 778
 779         priv = netdev_priv(dev);
 780         priv->dev = dev;
 781
 782         can_ml = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN);
 783         can_set_ml_priv(dev, can_ml);
 784
 785         if (echo_skb_max) {
 786                 priv->echo_skb_max = echo_skb_max;
 787                 priv->echo_skb = (void *)priv +
 788                         (size - echo_skb_max * sizeof(struct sk_buff *));
 789         }
 790
 791         priv->state = CAN_STATE_STOPPED;
 792
 793         INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
 794
 795         return dev;
 796 }
 797 EXPORT_SYMBOL_GPL(alloc_candev_mqs);
 798
 799 /* Free space of the CAN network device */
 800 void free_candev(struct net_device *dev)
 801 {
 802         free_netdev(dev);
 803 }
 804 EXPORT_SYMBOL_GPL(free_candev);
 805
 806 /* changing MTU and control mode for CAN/CANFD devices */
 807 int can_change_mtu(struct net_device *dev, int new_mtu)
 808 {
 809         struct can_priv *priv = netdev_priv(dev);
 810
 811         /* Do not allow changing the MTU while running */
 812         if (dev->flags & IFF_UP)
 813                 return -EBUSY;
 814
 815         /* allow change of MTU according to the CANFD ability of the device */
 816         switch (new_mtu) {
 817         case CAN_MTU:
 818                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 819                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 820                         return -EINVAL;
 821
 822                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 823                 break;
 824
 825         case CANFD_MTU:
 826                 /* check for potential CANFD ability */
 827                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 828                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 829                         return -EINVAL;
 830
 831                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 832                 break;
 833
 834         default:
 835                 return -EINVAL;
 836         }
 837
 838         dev->mtu = new_mtu;
 839         return 0;
 840 }
 841 EXPORT_SYMBOL_GPL(can_change_mtu);
 842
 843 /* Common open function when the device gets opened.
 844  *
 845  * This function should be called in the open function of the device
 846  * driver.
 847  */
 848 int open_candev(struct net_device *dev)
 849 {
 850         struct can_priv *priv = netdev_priv(dev);
 851
 852         if (!priv->bittiming.bitrate) {
 853                 netdev_err(dev, "bit-timing not yet defined\n");
 854                 return -EINVAL;
 855         }
 856
 857         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 858         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 859             (!priv->data_bittiming.bitrate ||
 860              priv->data_bittiming.bitrate < priv->bittiming.bitrate)) {
 861                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 862                 return -EINVAL;
 863         }
 864
 865         /* Switch carrier on if device was stopped while in bus-off state */
 866         if (!netif_carrier_ok(dev))
 867                 netif_carrier_on(dev);
 868
 869         return 0;
 870 }
 871 EXPORT_SYMBOL_GPL(open_candev);
 872
 873 #ifdef CONFIG_OF
 874 /* Common function that can be used to understand the limitation of
 875  * a transceiver when it provides no means to determine these limitations
 876  * at runtime.
 877  */
 878 void of_can_transceiver(struct net_device *dev)
 879 {
 880         struct device_node *dn;
 881         struct can_priv *priv = netdev_priv(dev);
 882         struct device_node *np = dev->dev.parent->of_node;
 883         int ret;
 884
 885         dn = of_get_child_by_name(np, "can-transceiver");
 886         if (!dn)
 887                 return;
 888
 889         ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max);
 890         of_node_put(dn);
 891         if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
 892                 netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
 893 }
 894 EXPORT_SYMBOL_GPL(of_can_transceiver);
 895 #endif
 896
 897 /* Common close function for cleanup before the device gets closed.
 898  *
 899  * This function should be called in the close function of the device
 900  * driver.
 901  */
 902 void close_candev(struct net_device *dev)
 903 {
 904         struct can_priv *priv = netdev_priv(dev);
 905
 906         cancel_delayed_work_sync(&priv->restart_work);
 907         can_flush_echo_skb(dev);
 908 }
 909 EXPORT_SYMBOL_GPL(close_candev);
 910
 911 /* CAN netlink interface */
 912 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 913         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 914         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 915         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 916         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 917         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 918         [IFLA_CAN_BITTIMING_CONST]
 919                                 = { .len = sizeof(struct can_bittiming_const) },
 920         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 921         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 922         [IFLA_CAN_DATA_BITTIMING]
 923                                 = { .len = sizeof(struct can_bittiming) },
 924         [IFLA_CAN_DATA_BITTIMING_CONST]
 925                                 = { .len = sizeof(struct can_bittiming_const) },
 926         [IFLA_CAN_TERMINATION]  = { .type = NLA_U16 },
 927 };
 928
 929 static int can_validate(struct nlattr *tb[], struct nlattr *data[],
 930                         struct netlink_ext_ack *extack)
 931 {
 932         bool is_can_fd = false;
 933
 934         /* Make sure that valid CAN FD configurations always consist of
 935          * - nominal/arbitration bittiming
 936          * - data bittiming
 937          * - control mode with CAN_CTRLMODE_FD set
 938          */
 939
 940         if (!data)
 941                 return 0;
 942
 943         if (data[IFLA_CAN_CTRLMODE]) {
 944                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 945
 946                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 947         }
 948
 949         if (is_can_fd) {
 950                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 951                         return -EOPNOTSUPP;
 952         }
 953
 954         if (data[IFLA_CAN_DATA_BITTIMING]) {
 955                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 956                         return -EOPNOTSUPP;
 957         }
 958
 959         return 0;
 960 }
 961
 962 static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 963                           struct nlattr *data[],
 964                           struct netlink_ext_ack *extack)
 965 {
 966         struct can_priv *priv = netdev_priv(dev);
 967         int err;
 968
 969         /* We need synchronization with dev->stop() */
 970         ASSERT_RTNL();
 971
 972         if (data[IFLA_CAN_BITTIMING]) {
 973                 struct can_bittiming bt;
 974
 975                 /* Do not allow changing bittiming while running */
 976                 if (dev->flags & IFF_UP)
 977                         return -EBUSY;
 978
 979                 /* Calculate bittiming parameters based on
 980                  * bittiming_const if set, otherwise pass bitrate
 981                  * directly via do_set_bitrate(). Bail out if neither
 982                  * is given.
 983                  */
 984                 if (!priv->bittiming_const && !priv->do_set_bittiming)
 985                         return -EOPNOTSUPP;
 986
 987                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 988                 err = can_get_bittiming(dev, &bt,
 989                                         priv->bittiming_const,
 990                                         priv->bitrate_const,
 991                                         priv->bitrate_const_cnt);
 992                 if (err)
 993                         return err;
 994
 995                 if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) {
 996                         netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n",
 997                                    priv->bitrate_max);
 998                         return -EINVAL;
 999                 }
1000
1001                 memcpy(&priv->bittiming, &bt, sizeof(bt));
1002
1003                 if (priv->do_set_bittiming) {
1004                         /* Finally, set the bit-timing registers */
1005                         err = priv->do_set_bittiming(dev);
1006                         if (err)
1007                                 return err;
1008                 }
1009         }
1010
1011         if (data[IFLA_CAN_CTRLMODE]) {
1012                 struct can_ctrlmode *cm;
1013                 u32 ctrlstatic;
1014                 u32 maskedflags;
1015
1016                 /* Do not allow changing controller mode while running */
1017                 if (dev->flags & IFF_UP)
1018                         return -EBUSY;
1019                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
1020                 ctrlstatic = priv->ctrlmode_static;
1021                 maskedflags = cm->flags & cm->mask;
1022
1023                 /* check whether provided bits are allowed to be passed */
1024                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
1025                         return -EOPNOTSUPP;
1026
1027                 /* do not check for static fd-non-iso if 'fd' is disabled */
1028                 if (!(maskedflags & CAN_CTRLMODE_FD))
1029                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
1030
1031                 /* make sure static options are provided by configuration */
1032                 if ((maskedflags & ctrlstatic) != ctrlstatic)
1033                         return -EOPNOTSUPP;
1034
1035                 /* clear bits to be modified and copy the flag values */
1036                 priv->ctrlmode &= ~cm->mask;
1037                 priv->ctrlmode |= maskedflags;
1038
1039                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
1040                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
1041                         dev->mtu = CANFD_MTU;
1042                 else
1043                         dev->mtu = CAN_MTU;
1044         }
1045
1046         if (data[IFLA_CAN_RESTART_MS]) {
1047                 /* Do not allow changing restart delay while running */
1048                 if (dev->flags & IFF_UP)
1049                         return -EBUSY;
1050                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
1051         }
1052
1053         if (data[IFLA_CAN_RESTART]) {
1054                 /* Do not allow a restart while not running */
1055                 if (!(dev->flags & IFF_UP))
1056                         return -EINVAL;
1057                 err = can_restart_now(dev);
1058                 if (err)
1059                         return err;
1060         }
1061
1062         if (data[IFLA_CAN_DATA_BITTIMING]) {
1063                 struct can_bittiming dbt;
1064
1065                 /* Do not allow changing bittiming while running */
1066                 if (dev->flags & IFF_UP)
1067                         return -EBUSY;
1068
1069                 /* Calculate bittiming parameters based on
1070                  * data_bittiming_const if set, otherwise pass bitrate
1071                  * directly via do_set_bitrate(). Bail out if neither
1072                  * is given.
1073                  */
1074                 if (!priv->data_bittiming_const && !priv->do_set_data_bittiming)
1075                         return -EOPNOTSUPP;
1076
1077                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
1078                        sizeof(dbt));
1079                 err = can_get_bittiming(dev, &dbt,
1080                                         priv->data_bittiming_const,
1081                                         priv->data_bitrate_const,
1082                                         priv->data_bitrate_const_cnt);
1083                 if (err)
1084                         return err;
1085
1086                 if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
1087                         netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
1088                                    priv->bitrate_max);
1089                         return -EINVAL;
1090                 }
1091
1092                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
1093
1094                 if (priv->do_set_data_bittiming) {
1095                         /* Finally, set the bit-timing registers */
1096                         err = priv->do_set_data_bittiming(dev);
1097                         if (err)
1098                                 return err;
1099                 }
1100         }
1101
1102         if (data[IFLA_CAN_TERMINATION]) {
1103                 const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]);
1104                 const unsigned int num_term = priv->termination_const_cnt;
1105                 unsigned int i;
1106
1107                 if (!priv->do_set_termination)
1108                         return -EOPNOTSUPP;
1109
1110                 /* check whether given value is supported by the interface */
1111                 for (i = 0; i < num_term; i++) {
1112                         if (termval == priv->termination_const[i])
1113                                 break;
1114                 }
1115                 if (i >= num_term)
1116                         return -EINVAL;
1117
1118                 /* Finally, set the termination value */
1119                 err = priv->do_set_termination(dev, termval);
1120                 if (err)
1121                         return err;
1122
1123                 priv->termination = termval;
1124         }
1125
1126         return 0;
1127 }
1128
1129 static size_t can_get_size(const struct net_device *dev)
1130 {
1131         struct can_priv *priv = netdev_priv(dev);
1132         size_t size = 0;
1133
1134         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
1135                 size += nla_total_size(sizeof(struct can_bittiming));
1136         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
1137                 size += nla_total_size(sizeof(struct can_bittiming_const));
1138         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
1139         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
1140         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
1141         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
1142         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
1143                 size += nla_total_size(sizeof(struct can_berr_counter));
1144         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
1145                 size += nla_total_size(sizeof(struct can_bittiming));
1146         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
1147                 size += nla_total_size(sizeof(struct can_bittiming_const));
1148         if (priv->termination_const) {
1149                 size += nla_total_size(sizeof(priv->termination));              /* IFLA_CAN_TERMINATION */
1150                 size += nla_total_size(sizeof(*priv->termination_const) *       /* IFLA_CAN_TERMINATION_CONST */
1151                                        priv->termination_const_cnt);
1152         }
1153         if (priv->bitrate_const)                                /* IFLA_CAN_BITRATE_CONST */
1154                 size += nla_total_size(sizeof(*priv->bitrate_const) *
1155                                        priv->bitrate_const_cnt);
1156         if (priv->data_bitrate_const)                           /* IFLA_CAN_DATA_BITRATE_CONST */
1157                 size += nla_total_size(sizeof(*priv->data_bitrate_const) *
1158                                        priv->data_bitrate_const_cnt);
1159         size += sizeof(priv->bitrate_max);                      /* IFLA_CAN_BITRATE_MAX */
1160
1161         return size;
1162 }
1163
1164 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
1165 {
1166         struct can_priv *priv = netdev_priv(dev);
1167         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
1168         struct can_berr_counter bec = { };
1169         enum can_state state = priv->state;
1170
1171         if (priv->do_get_state)
1172                 priv->do_get_state(dev, &state);
1173
1174         if ((priv->bittiming.bitrate &&
1175              nla_put(skb, IFLA_CAN_BITTIMING,
1176                      sizeof(priv->bittiming), &priv->bittiming)) ||
1177
1178             (priv->bittiming_const &&
1179              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1180                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1181
1182             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1183             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1184             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1185             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1186
1187             (priv->do_get_berr_counter &&
1188              !priv->do_get_berr_counter(dev, &bec) &&
1189              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1190
1191             (priv->data_bittiming.bitrate &&
1192              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1193                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1194
1195             (priv->data_bittiming_const &&
1196              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1197                      sizeof(*priv->data_bittiming_const),
1198                      priv->data_bittiming_const)) ||
1199
1200             (priv->termination_const &&
1201              (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||
1202               nla_put(skb, IFLA_CAN_TERMINATION_CONST,
1203                       sizeof(*priv->termination_const) *
1204                       priv->termination_const_cnt,
1205                       priv->termination_const))) ||
1206
1207             (priv->bitrate_const &&
1208              nla_put(skb, IFLA_CAN_BITRATE_CONST,
1209                      sizeof(*priv->bitrate_const) *
1210                      priv->bitrate_const_cnt,
1211                      priv->bitrate_const)) ||
1212
1213             (priv->data_bitrate_const &&
1214              nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
1215                      sizeof(*priv->data_bitrate_const) *
1216                      priv->data_bitrate_const_cnt,
1217                      priv->data_bitrate_const)) ||
1218
1219             (nla_put(skb, IFLA_CAN_BITRATE_MAX,
1220                      sizeof(priv->bitrate_max),
1221                      &priv->bitrate_max))
1222             )
1223
1224                 return -EMSGSIZE;
1225
1226         return 0;
1227 }
1228
1229 static size_t can_get_xstats_size(const struct net_device *dev)
1230 {
1231         return sizeof(struct can_device_stats);
1232 }
1233
1234 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1235 {
1236         struct can_priv *priv = netdev_priv(dev);
1237
1238         if (nla_put(skb, IFLA_INFO_XSTATS,
1239                     sizeof(priv->can_stats), &priv->can_stats))
1240                 goto nla_put_failure;
1241         return 0;
1242
1243 nla_put_failure:
1244         return -EMSGSIZE;
1245 }
1246
1247 static int can_newlink(struct net *src_net, struct net_device *dev,
1248                        struct nlattr *tb[], struct nlattr *data[],
1249                        struct netlink_ext_ack *extack)
1250 {
1251         return -EOPNOTSUPP;
1252 }
1253
1254 static void can_dellink(struct net_device *dev, struct list_head *head)
1255 {
1256 }
1257
1258 static struct rtnl_link_ops can_link_ops __read_mostly = {
1259         .kind           = "can",
1260         .netns_refund   = true,
1261         .maxtype        = IFLA_CAN_MAX,
1262         .policy         = can_policy,
1263         .setup          = can_setup,
1264         .validate       = can_validate,
1265         .newlink        = can_newlink,
1266         .changelink     = can_changelink,
1267         .dellink        = can_dellink,
1268         .get_size       = can_get_size,
1269         .fill_info      = can_fill_info,
1270         .get_xstats_size = can_get_xstats_size,
1271         .fill_xstats    = can_fill_xstats,
1272 };
1273
1274 /* Register the CAN network device */
1275 int register_candev(struct net_device *dev)
1276 {
1277         struct can_priv *priv = netdev_priv(dev);
1278
1279         /* Ensure termination_const, termination_const_cnt and
1280          * do_set_termination consistency. All must be either set or
1281          * unset.
1282          */
1283         if ((!priv->termination_const != !priv->termination_const_cnt) ||
1284             (!priv->termination_const != !priv->do_set_termination))
1285                 return -EINVAL;
1286
1287         if (!priv->bitrate_const != !priv->bitrate_const_cnt)
1288                 return -EINVAL;
1289
1290         if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
1291                 return -EINVAL;
1292
1293         dev->rtnl_link_ops = &can_link_ops;
1294         netif_carrier_off(dev);
1295
1296         return register_netdev(dev);
1297 }
1298 EXPORT_SYMBOL_GPL(register_candev);
1299
1300 /* Unregister the CAN network device */
1301 void unregister_candev(struct net_device *dev)
1302 {
1303         unregister_netdev(dev);
1304 }
1305 EXPORT_SYMBOL_GPL(unregister_candev);
1306
1307 /* Test if a network device is a candev based device
1308  * and return the can_priv* if so.
1309  */
1310 struct can_priv *safe_candev_priv(struct net_device *dev)
1311 {
1312         if (dev->type != ARPHRD_CAN || dev->rtnl_link_ops != &can_link_ops)
1313                 return NULL;
1314
1315         return netdev_priv(dev);
1316 }
1317 EXPORT_SYMBOL_GPL(safe_candev_priv);
1318
1319 static __init int can_dev_init(void)
1320 {
1321         int err;
1322
1323         can_led_notifier_init();
1324
1325         err = rtnl_link_register(&can_link_ops);
1326         if (!err)
1327                 pr_info(MOD_DESC "\n");
1328
1329         return err;
1330 }
1331 module_init(can_dev_init);
1332
1333 static __exit void can_dev_exit(void)
1334 {
1335         rtnl_link_unregister(&can_link_ops);
1336
1337         can_led_notifier_exit();
1338 }
1339 module_exit(can_dev_exit);
1340
1341 MODULE_ALIAS_RTNL_LINK("can");