drivers/net/can/dev.c

   1 /*
   2  * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
   3  * Copyright (C) 2006 Andrey Volkov, Varma Electronics
   4  * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the version 2 of the GNU General Public License
   8  * as published by the Free Software Foundation
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/kernel.h>
  21 #include <linux/slab.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/if_arp.h>
  24 #include <linux/workqueue.h>
  25 #include <linux/can.h>
  26 #include <linux/can/dev.h>
  27 #include <linux/can/skb.h>
  28 #include <linux/can/netlink.h>
  29 #include <linux/can/led.h>
  30 #include <net/rtnetlink.h>
  31
  32 #define MOD_DESC "CAN device driver interface"
  33
  34 MODULE_DESCRIPTION(MOD_DESC);
  35 MODULE_LICENSE("GPL v2");
  36 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
  37
  38 /* CAN DLC to real data length conversion helpers */
  39
  40 static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
  41                              8, 12, 16, 20, 24, 32, 48, 64};
  42
  43 /* get data length from can_dlc with sanitized can_dlc */
  44 u8 can_dlc2len(u8 can_dlc)
  45 {
  46         return dlc2len[can_dlc & 0x0F];
  47 }
  48 EXPORT_SYMBOL_GPL(can_dlc2len);
  49
  50 static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,         /* 0 - 8 */
  51                              9, 9, 9, 9,                        /* 9 - 12 */
  52                              10, 10, 10, 10,                    /* 13 - 16 */
  53                              11, 11, 11, 11,                    /* 17 - 20 */
  54                              12, 12, 12, 12,                    /* 21 - 24 */
  55                              13, 13, 13, 13, 13, 13, 13, 13,    /* 25 - 32 */
  56                              14, 14, 14, 14, 14, 14, 14, 14,    /* 33 - 40 */
  57                              14, 14, 14, 14, 14, 14, 14, 14,    /* 41 - 48 */
  58                              15, 15, 15, 15, 15, 15, 15, 15,    /* 49 - 56 */
  59                              15, 15, 15, 15, 15, 15, 15, 15};   /* 57 - 64 */
  60
  61 /* map the sanitized data length to an appropriate data length code */
  62 u8 can_len2dlc(u8 len)
  63 {
  64         if (unlikely(len > 64))
  65                 return 0xF;
  66
  67         return len2dlc[len];
  68 }
  69 EXPORT_SYMBOL_GPL(can_len2dlc);
  70
  71 #ifdef CONFIG_CAN_CALC_BITTIMING
  72 #define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
  73 #define CAN_CALC_SYNC_SEG 1
  74
  75 /*
  76  * Bit-timing calculation derived from:
  77  *
  78  * Code based on LinCAN sources and H8S2638 project
  79  * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
  80  * Copyright 2005      Stanislav Marek
  81  * email: pisa@cmp.felk.cvut.cz
  82  *
  83  * Calculates proper bit-timing parameters for a specified bit-rate
  84  * and sample-point, which can then be used to set the bit-timing
  85  * registers of the CAN controller. You can find more information
  86  * in the header file linux/can/netlink.h.
  87  */
  88 static int can_update_sample_point(const struct can_bittiming_const *btc,
  89                           unsigned int sample_point_nominal, unsigned int tseg,
  90                           unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
  91                           unsigned int *sample_point_error_ptr)
  92 {
  93         unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
  94         unsigned int sample_point, best_sample_point = 0;
  95         unsigned int tseg1, tseg2;
  96         int i;
  97
  98         for (i = 0; i <= 1; i++) {
  99                 tseg2 = tseg + CAN_CALC_SYNC_SEG - (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) / 1000 - i;
 100                 tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
 101                 tseg1 = tseg - tseg2;
 102                 if (tseg1 > btc->tseg1_max) {
 103                         tseg1 = btc->tseg1_max;
 104                         tseg2 = tseg - tseg1;
 105                 }
 106
 107                 sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) / (tseg + CAN_CALC_SYNC_SEG);
 108                 sample_point_error = abs(sample_point_nominal - sample_point);
 109
 110                 if ((sample_point <= sample_point_nominal) && (sample_point_error < best_sample_point_error)) {
 111                         best_sample_point = sample_point;
 112                         best_sample_point_error = sample_point_error;
 113                         *tseg1_ptr = tseg1;
 114                         *tseg2_ptr = tseg2;
 115                 }
 116         }
 117
 118         if (sample_point_error_ptr)
 119                 *sample_point_error_ptr = best_sample_point_error;
 120
 121         return best_sample_point;
 122 }
 123
 124 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 125                               const struct can_bittiming_const *btc)
 126 {
 127         struct can_priv *priv = netdev_priv(dev);
 128         unsigned int bitrate;                   /* current bitrate */
 129         unsigned int bitrate_error;             /* difference between current and nominal value */
 130         unsigned int best_bitrate_error = UINT_MAX;
 131         unsigned int sample_point_error;        /* difference between current and nominal value */
 132         unsigned int best_sample_point_error = UINT_MAX;
 133         unsigned int sample_point_nominal;      /* nominal sample point */
 134         unsigned int best_tseg = 0;             /* current best value for tseg */
 135         unsigned int best_brp = 0;              /* current best value for brp */
 136         unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
 137         u64 v64;
 138
 139         /* Use CiA recommended sample points */
 140         if (bt->sample_point) {
 141                 sample_point_nominal = bt->sample_point;
 142         } else {
 143                 if (bt->bitrate > 800000)
 144                         sample_point_nominal = 750;
 145                 else if (bt->bitrate > 500000)
 146                         sample_point_nominal = 800;
 147                 else
 148                         sample_point_nominal = 875;
 149         }
 150
 151         /* tseg even = round down, odd = round up */
 152         for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
 153              tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
 154                 tsegall = CAN_CALC_SYNC_SEG + tseg / 2;
 155
 156                 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
 157                 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
 158
 159                 /* choose brp step which is possible in system */
 160                 brp = (brp / btc->brp_inc) * btc->brp_inc;
 161                 if ((brp < btc->brp_min) || (brp > btc->brp_max))
 162                         continue;
 163
 164                 bitrate = priv->clock.freq / (brp * tsegall);
 165                 bitrate_error = abs(bt->bitrate - bitrate);
 166
 167                 /* tseg brp biterror */
 168                 if (bitrate_error > best_bitrate_error)
 169                         continue;
 170
 171                 /* reset sample point error if we have a better bitrate */
 172                 if (bitrate_error < best_bitrate_error)
 173                         best_sample_point_error = UINT_MAX;
 174
 175                 can_update_sample_point(btc, sample_point_nominal, tseg / 2, &tseg1, &tseg2, &sample_point_error);
 176                 if (sample_point_error > best_sample_point_error)
 177                         continue;
 178
 179                 best_sample_point_error = sample_point_error;
 180                 best_bitrate_error = bitrate_error;
 181                 best_tseg = tseg / 2;
 182                 best_brp = brp;
 183
 184                 if (bitrate_error == 0 && sample_point_error == 0)
 185                         break;
 186         }
 187
 188         if (best_bitrate_error) {
 189                 /* Error in one-tenth of a percent */
 190                 v64 = (u64)best_bitrate_error * 1000;
 191                 do_div(v64, bt->bitrate);
 192                 bitrate_error = (u32)v64;
 193                 if (bitrate_error > CAN_CALC_MAX_ERROR) {
 194                         netdev_err(dev,
 195                                    "bitrate error %d.%d%% too high\n",
 196                                    bitrate_error / 10, bitrate_error % 10);
 197                         return -EDOM;
 198                 }
 199                 netdev_warn(dev, "bitrate error %d.%d%%\n",
 200                             bitrate_error / 10, bitrate_error % 10);
 201         }
 202
 203         /* real sample point */
 204         bt->sample_point = can_update_sample_point(btc, sample_point_nominal, best_tseg,
 205                                           &tseg1, &tseg2, NULL);
 206
 207         v64 = (u64)best_brp * 1000 * 1000 * 1000;
 208         do_div(v64, priv->clock.freq);
 209         bt->tq = (u32)v64;
 210         bt->prop_seg = tseg1 / 2;
 211         bt->phase_seg1 = tseg1 - bt->prop_seg;
 212         bt->phase_seg2 = tseg2;
 213
 214         /* check for sjw user settings */
 215         if (!bt->sjw || !btc->sjw_max) {
 216                 bt->sjw = 1;
 217         } else {
 218                 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
 219                 if (bt->sjw > btc->sjw_max)
 220                         bt->sjw = btc->sjw_max;
 221                 /* bt->sjw must not be higher than tseg2 */
 222                 if (tseg2 < bt->sjw)
 223                         bt->sjw = tseg2;
 224         }
 225
 226         bt->brp = best_brp;
 227
 228         /* real bitrate */
 229         bt->bitrate = priv->clock.freq / (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2));
 230
 231         return 0;
 232 }
 233 #else /* !CONFIG_CAN_CALC_BITTIMING */
 234 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 235                               const struct can_bittiming_const *btc)
 236 {
 237         netdev_err(dev, "bit-timing calculation not available\n");
 238         return -EINVAL;
 239 }
 240 #endif /* CONFIG_CAN_CALC_BITTIMING */
 241
 242 /*
 243  * Checks the validity of the specified bit-timing parameters prop_seg,
 244  * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
 245  * prescaler value brp. You can find more information in the header
 246  * file linux/can/netlink.h.
 247  */
 248 static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
 249                                const struct can_bittiming_const *btc)
 250 {
 251         struct can_priv *priv = netdev_priv(dev);
 252         int tseg1, alltseg;
 253         u64 brp64;
 254
 255         tseg1 = bt->prop_seg + bt->phase_seg1;
 256         if (!bt->sjw)
 257                 bt->sjw = 1;
 258         if (bt->sjw > btc->sjw_max ||
 259             tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
 260             bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
 261                 return -ERANGE;
 262
 263         brp64 = (u64)priv->clock.freq * (u64)bt->tq;
 264         if (btc->brp_inc > 1)
 265                 do_div(brp64, btc->brp_inc);
 266         brp64 += 500000000UL - 1;
 267         do_div(brp64, 1000000000UL); /* the practicable BRP */
 268         if (btc->brp_inc > 1)
 269                 brp64 *= btc->brp_inc;
 270         bt->brp = (u32)brp64;
 271
 272         if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
 273                 return -EINVAL;
 274
 275         alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
 276         bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
 277         bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
 278
 279         return 0;
 280 }
 281
 282 /* Checks the validity of predefined bitrate settings */
 283 static int can_validate_bitrate(struct net_device *dev, struct can_bittiming *bt,
 284                                 const u32 *bitrate_const,
 285                                 const unsigned int bitrate_const_cnt)
 286 {
 287         struct can_priv *priv = netdev_priv(dev);
 288         unsigned int i;
 289
 290         for (i = 0; i < bitrate_const_cnt; i++) {
 291                 if (bt->bitrate == bitrate_const[i])
 292                         break;
 293         }
 294
 295         if (i >= priv->bitrate_const_cnt)
 296                 return -EINVAL;
 297
 298         return 0;
 299 }
 300
 301 static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
 302                              const struct can_bittiming_const *btc,
 303                              const u32 *bitrate_const,
 304                              const unsigned int bitrate_const_cnt)
 305 {
 306         int err;
 307
 308         /*
 309          * Depending on the given can_bittiming parameter structure the CAN
 310          * timing parameters are calculated based on the provided bitrate OR
 311          * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
 312          * provided directly which are then checked and fixed up.
 313          */
 314         if (!bt->tq && bt->bitrate && btc)
 315                 err = can_calc_bittiming(dev, bt, btc);
 316         else if (bt->tq && !bt->bitrate && btc)
 317                 err = can_fixup_bittiming(dev, bt, btc);
 318         else if (!bt->tq && bt->bitrate && bitrate_const)
 319                 err = can_validate_bitrate(dev, bt, bitrate_const,
 320                                            bitrate_const_cnt);
 321         else
 322                 err = -EINVAL;
 323
 324         return err;
 325 }
 326
 327 static void can_update_state_error_stats(struct net_device *dev,
 328                                          enum can_state new_state)
 329 {
 330         struct can_priv *priv = netdev_priv(dev);
 331
 332         if (new_state <= priv->state)
 333                 return;
 334
 335         switch (new_state) {
 336         case CAN_STATE_ERROR_WARNING:
 337                 priv->can_stats.error_warning++;
 338                 break;
 339         case CAN_STATE_ERROR_PASSIVE:
 340                 priv->can_stats.error_passive++;
 341                 break;
 342         case CAN_STATE_BUS_OFF:
 343                 priv->can_stats.bus_off++;
 344                 break;
 345         default:
 346                 break;
 347         }
 348 }
 349
 350 static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
 351 {
 352         switch (state) {
 353         case CAN_STATE_ERROR_ACTIVE:
 354                 return CAN_ERR_CRTL_ACTIVE;
 355         case CAN_STATE_ERROR_WARNING:
 356                 return CAN_ERR_CRTL_TX_WARNING;
 357         case CAN_STATE_ERROR_PASSIVE:
 358                 return CAN_ERR_CRTL_TX_PASSIVE;
 359         default:
 360                 return 0;
 361         }
 362 }
 363
 364 static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
 365 {
 366         switch (state) {
 367         case CAN_STATE_ERROR_ACTIVE:
 368                 return CAN_ERR_CRTL_ACTIVE;
 369         case CAN_STATE_ERROR_WARNING:
 370                 return CAN_ERR_CRTL_RX_WARNING;
 371         case CAN_STATE_ERROR_PASSIVE:
 372                 return CAN_ERR_CRTL_RX_PASSIVE;
 373         default:
 374                 return 0;
 375         }
 376 }
 377
 378 void can_change_state(struct net_device *dev, struct can_frame *cf,
 379                       enum can_state tx_state, enum can_state rx_state)
 380 {
 381         struct can_priv *priv = netdev_priv(dev);
 382         enum can_state new_state = max(tx_state, rx_state);
 383
 384         if (unlikely(new_state == priv->state)) {
 385                 netdev_warn(dev, "%s: oops, state did not change", __func__);
 386                 return;
 387         }
 388
 389         netdev_dbg(dev, "New error state: %d\n", new_state);
 390
 391         can_update_state_error_stats(dev, new_state);
 392         priv->state = new_state;
 393
 394         if (!cf)
 395                 return;
 396
 397         if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
 398                 cf->can_id |= CAN_ERR_BUSOFF;
 399                 return;
 400         }
 401
 402         cf->can_id |= CAN_ERR_CRTL;
 403         cf->data[1] |= tx_state >= rx_state ?
 404                        can_tx_state_to_frame(dev, tx_state) : 0;
 405         cf->data[1] |= tx_state <= rx_state ?
 406                        can_rx_state_to_frame(dev, rx_state) : 0;
 407 }
 408 EXPORT_SYMBOL_GPL(can_change_state);
 409
 410 /*
 411  * Local echo of CAN messages
 412  *
 413  * CAN network devices *should* support a local echo functionality
 414  * (see Documentation/networking/can.txt). To test the handling of CAN
 415  * interfaces that do not support the local echo both driver types are
 416  * implemented. In the case that the driver does not support the echo
 417  * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
 418  * to perform the echo as a fallback solution.
 419  */
 420 static void can_flush_echo_skb(struct net_device *dev)
 421 {
 422         struct can_priv *priv = netdev_priv(dev);
 423         struct net_device_stats *stats = &dev->stats;
 424         int i;
 425
 426         for (i = 0; i < priv->echo_skb_max; i++) {
 427                 if (priv->echo_skb[i]) {
 428                         kfree_skb(priv->echo_skb[i]);
 429                         priv->echo_skb[i] = NULL;
 430                         stats->tx_dropped++;
 431                         stats->tx_aborted_errors++;
 432                 }
 433         }
 434 }
 435
 436 /*
 437  * Put the skb on the stack to be looped backed locally lateron
 438  *
 439  * The function is typically called in the start_xmit function
 440  * of the device driver. The driver must protect access to
 441  * priv->echo_skb, if necessary.
 442  */
 443 void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 444                       unsigned int idx)
 445 {
 446         struct can_priv *priv = netdev_priv(dev);
 447
 448         BUG_ON(idx >= priv->echo_skb_max);
 449
 450         /* check flag whether this packet has to be looped back */
 451         if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
 452             (skb->protocol != htons(ETH_P_CAN) &&
 453              skb->protocol != htons(ETH_P_CANFD))) {
 454                 kfree_skb(skb);
 455                 return;
 456         }
 457
 458         if (!priv->echo_skb[idx]) {
 459
 460                 skb = can_create_echo_skb(skb);
 461                 if (!skb)
 462                         return;
 463
 464                 /* make settings for echo to reduce code in irq context */
 465                 skb->pkt_type = PACKET_BROADCAST;
 466                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 467                 skb->dev = dev;
 468
 469                 /* save this skb for tx interrupt echo handling */
 470                 priv->echo_skb[idx] = skb;
 471         } else {
 472                 /* locking problem with netif_stop_queue() ?? */
 473                 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
 474                 kfree_skb(skb);
 475         }
 476 }
 477 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 478
 479 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
 480 {
 481         struct can_priv *priv = netdev_priv(dev);
 482
 483         if (idx >= priv->echo_skb_max) {
 484                 netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
 485                            __func__, idx, priv->echo_skb_max);
 486                 return NULL;
 487         }
 488
 489         if (priv->echo_skb[idx]) {
 490                 /* Using "struct canfd_frame::len" for the frame
 491                  * length is supported on both CAN and CANFD frames.
 492                  */
 493                 struct sk_buff *skb = priv->echo_skb[idx];
 494                 struct canfd_frame *cf = (struct canfd_frame *)skb->data;
 495
 496                 /* get the real payload length for netdev statistics */
 497                 if (cf->can_id & CAN_RTR_FLAG)
 498                         *len_ptr = 0;
 499                 else
 500                         *len_ptr = cf->len;
 501
 502                 priv->echo_skb[idx] = NULL;
 503
 504                 return skb;
 505         }
 506
 507         return NULL;
 508 }
 509
 510 /*
 511  * Get the skb from the stack and loop it back locally
 512  *
 513  * The function is typically called when the TX done interrupt
 514  * is handled in the device driver. The driver must protect
 515  * access to priv->echo_skb, if necessary.
 516  */
 517 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 518 {
 519         struct sk_buff *skb;
 520         u8 len;
 521
 522         skb = __can_get_echo_skb(dev, idx, &len);
 523         if (!skb)
 524                 return 0;
 525
 526         skb_get(skb);
 527         if (netif_rx(skb) == NET_RX_SUCCESS)
 528                 dev_consume_skb_any(skb);
 529         else
 530                 dev_kfree_skb_any(skb);
 531
 532         return len;
 533 }
 534 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 535
 536 /*
 537   * Remove the skb from the stack and free it.
 538   *
 539   * The function is typically called when TX failed.
 540   */
 541 void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 542 {
 543         struct can_priv *priv = netdev_priv(dev);
 544
 545         BUG_ON(idx >= priv->echo_skb_max);
 546
 547         if (priv->echo_skb[idx]) {
 548                 dev_kfree_skb_any(priv->echo_skb[idx]);
 549                 priv->echo_skb[idx] = NULL;
 550         }
 551 }
 552 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 553
 554 /*
 555  * CAN device restart for bus-off recovery
 556  */
 557 static void can_restart(struct net_device *dev)
 558 {
 559         struct can_priv *priv = netdev_priv(dev);
 560         struct net_device_stats *stats = &dev->stats;
 561         struct sk_buff *skb;
 562         struct can_frame *cf;
 563         int err;
 564
 565         BUG_ON(netif_carrier_ok(dev));
 566
 567         /*
 568          * No synchronization needed because the device is bus-off and
 569          * no messages can come in or go out.
 570          */
 571         can_flush_echo_skb(dev);
 572
 573         /* send restart message upstream */
 574         skb = alloc_can_err_skb(dev, &cf);
 575         if (skb == NULL) {
 576                 err = -ENOMEM;
 577                 goto restart;
 578         }
 579         cf->can_id |= CAN_ERR_RESTARTED;
 580
 581         stats->rx_packets++;
 582         stats->rx_bytes += cf->can_dlc;
 583
 584         netif_rx_ni(skb);
 585
 586 restart:
 587         netdev_dbg(dev, "restarted\n");
 588         priv->can_stats.restarts++;
 589
 590         /* Now restart the device */
 591         err = priv->do_set_mode(dev, CAN_MODE_START);
 592
 593         netif_carrier_on(dev);
 594         if (err)
 595                 netdev_err(dev, "Error %d during restart", err);
 596 }
 597
 598 static void can_restart_work(struct work_struct *work)
 599 {
 600         struct delayed_work *dwork = to_delayed_work(work);
 601         struct can_priv *priv = container_of(dwork, struct can_priv, restart_work);
 602
 603         can_restart(priv->dev);
 604 }
 605
 606 int can_restart_now(struct net_device *dev)
 607 {
 608         struct can_priv *priv = netdev_priv(dev);
 609
 610         /*
 611          * A manual restart is only permitted if automatic restart is
 612          * disabled and the device is in the bus-off state
 613          */
 614         if (priv->restart_ms)
 615                 return -EINVAL;
 616         if (priv->state != CAN_STATE_BUS_OFF)
 617                 return -EBUSY;
 618
 619         cancel_delayed_work_sync(&priv->restart_work);
 620         can_restart(dev);
 621
 622         return 0;
 623 }
 624
 625 /*
 626  * CAN bus-off
 627  *
 628  * This functions should be called when the device goes bus-off to
 629  * tell the netif layer that no more packets can be sent or received.
 630  * If enabled, a timer is started to trigger bus-off recovery.
 631  */
 632 void can_bus_off(struct net_device *dev)
 633 {
 634         struct can_priv *priv = netdev_priv(dev);
 635
 636         netdev_info(dev, "bus-off\n");
 637
 638         netif_carrier_off(dev);
 639
 640         if (priv->restart_ms)
 641                 schedule_delayed_work(&priv->restart_work,
 642                                       msecs_to_jiffies(priv->restart_ms));
 643 }
 644 EXPORT_SYMBOL_GPL(can_bus_off);
 645
 646 static void can_setup(struct net_device *dev)
 647 {
 648         dev->type = ARPHRD_CAN;
 649         dev->mtu = CAN_MTU;
 650         dev->hard_header_len = 0;
 651         dev->addr_len = 0;
 652         dev->tx_queue_len = 10;
 653
 654         /* New-style flags. */
 655         dev->flags = IFF_NOARP;
 656         dev->features = NETIF_F_HW_CSUM;
 657 }
 658
 659 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 660 {
 661         struct sk_buff *skb;
 662
 663         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 664                                sizeof(struct can_frame));
 665         if (unlikely(!skb))
 666                 return NULL;
 667
 668         skb->protocol = htons(ETH_P_CAN);
 669         skb->pkt_type = PACKET_BROADCAST;
 670         skb->ip_summed = CHECKSUM_UNNECESSARY;
 671
 672         skb_reset_mac_header(skb);
 673         skb_reset_network_header(skb);
 674         skb_reset_transport_header(skb);
 675
 676         can_skb_reserve(skb);
 677         can_skb_prv(skb)->ifindex = dev->ifindex;
 678         can_skb_prv(skb)->skbcnt = 0;
 679
 680         *cf = skb_put(skb, sizeof(struct can_frame));
 681         memset(*cf, 0, sizeof(struct can_frame));
 682
 683         return skb;
 684 }
 685 EXPORT_SYMBOL_GPL(alloc_can_skb);
 686
 687 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 688                                 struct canfd_frame **cfd)
 689 {
 690         struct sk_buff *skb;
 691
 692         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 693                                sizeof(struct canfd_frame));
 694         if (unlikely(!skb))
 695                 return NULL;
 696
 697         skb->protocol = htons(ETH_P_CANFD);
 698         skb->pkt_type = PACKET_BROADCAST;
 699         skb->ip_summed = CHECKSUM_UNNECESSARY;
 700
 701         skb_reset_mac_header(skb);
 702         skb_reset_network_header(skb);
 703         skb_reset_transport_header(skb);
 704
 705         can_skb_reserve(skb);
 706         can_skb_prv(skb)->ifindex = dev->ifindex;
 707         can_skb_prv(skb)->skbcnt = 0;
 708
 709         *cfd = skb_put(skb, sizeof(struct canfd_frame));
 710         memset(*cfd, 0, sizeof(struct canfd_frame));
 711
 712         return skb;
 713 }
 714 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 715
 716 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 717 {
 718         struct sk_buff *skb;
 719
 720         skb = alloc_can_skb(dev, cf);
 721         if (unlikely(!skb))
 722                 return NULL;
 723
 724         (*cf)->can_id = CAN_ERR_FLAG;
 725         (*cf)->can_dlc = CAN_ERR_DLC;
 726
 727         return skb;
 728 }
 729 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 730
 731 /*
 732  * Allocate and setup space for the CAN network device
 733  */
 734 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
 735 {
 736         struct net_device *dev;
 737         struct can_priv *priv;
 738         int size;
 739
 740         if (echo_skb_max)
 741                 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
 742                         echo_skb_max * sizeof(struct sk_buff *);
 743         else
 744                 size = sizeof_priv;
 745
 746         dev = alloc_netdev(size, "can%d", NET_NAME_UNKNOWN, can_setup);
 747         if (!dev)
 748                 return NULL;
 749
 750         priv = netdev_priv(dev);
 751         priv->dev = dev;
 752
 753         if (echo_skb_max) {
 754                 priv->echo_skb_max = echo_skb_max;
 755                 priv->echo_skb = (void *)priv +
 756                         ALIGN(sizeof_priv, sizeof(struct sk_buff *));
 757         }
 758
 759         priv->state = CAN_STATE_STOPPED;
 760
 761         INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
 762
 763         return dev;
 764 }
 765 EXPORT_SYMBOL_GPL(alloc_candev);
 766
 767 /*
 768  * Free space of the CAN network device
 769  */
 770 void free_candev(struct net_device *dev)
 771 {
 772         free_netdev(dev);
 773 }
 774 EXPORT_SYMBOL_GPL(free_candev);
 775
 776 /*
 777  * changing MTU and control mode for CAN/CANFD devices
 778  */
 779 int can_change_mtu(struct net_device *dev, int new_mtu)
 780 {
 781         struct can_priv *priv = netdev_priv(dev);
 782
 783         /* Do not allow changing the MTU while running */
 784         if (dev->flags & IFF_UP)
 785                 return -EBUSY;
 786
 787         /* allow change of MTU according to the CANFD ability of the device */
 788         switch (new_mtu) {
 789         case CAN_MTU:
 790                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 791                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 792                         return -EINVAL;
 793
 794                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 795                 break;
 796
 797         case CANFD_MTU:
 798                 /* check for potential CANFD ability */
 799                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 800                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 801                         return -EINVAL;
 802
 803                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 804                 break;
 805
 806         default:
 807                 return -EINVAL;
 808         }
 809
 810         dev->mtu = new_mtu;
 811         return 0;
 812 }
 813 EXPORT_SYMBOL_GPL(can_change_mtu);
 814
 815 /*
 816  * Common open function when the device gets opened.
 817  *
 818  * This function should be called in the open function of the device
 819  * driver.
 820  */
 821 int open_candev(struct net_device *dev)
 822 {
 823         struct can_priv *priv = netdev_priv(dev);
 824
 825         if (!priv->bittiming.bitrate) {
 826                 netdev_err(dev, "bit-timing not yet defined\n");
 827                 return -EINVAL;
 828         }
 829
 830         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 831         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 832             (!priv->data_bittiming.bitrate ||
 833              (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
 834                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 835                 return -EINVAL;
 836         }
 837
 838         /* Switch carrier on if device was stopped while in bus-off state */
 839         if (!netif_carrier_ok(dev))
 840                 netif_carrier_on(dev);
 841
 842         return 0;
 843 }
 844 EXPORT_SYMBOL_GPL(open_candev);
 845
 846 /*
 847  * Common close function for cleanup before the device gets closed.
 848  *
 849  * This function should be called in the close function of the device
 850  * driver.
 851  */
 852 void close_candev(struct net_device *dev)
 853 {
 854         struct can_priv *priv = netdev_priv(dev);
 855
 856         cancel_delayed_work_sync(&priv->restart_work);
 857         can_flush_echo_skb(dev);
 858 }
 859 EXPORT_SYMBOL_GPL(close_candev);
 860
 861 /*
 862  * CAN netlink interface
 863  */
 864 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 865         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 866         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 867         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 868         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 869         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 870         [IFLA_CAN_BITTIMING_CONST]
 871                                 = { .len = sizeof(struct can_bittiming_const) },
 872         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 873         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 874         [IFLA_CAN_DATA_BITTIMING]
 875                                 = { .len = sizeof(struct can_bittiming) },
 876         [IFLA_CAN_DATA_BITTIMING_CONST]
 877                                 = { .len = sizeof(struct can_bittiming_const) },
 878         [IFLA_CAN_TERMINATION]  = { .type = NLA_U16 },
 879 };
 880
 881 static int can_validate(struct nlattr *tb[], struct nlattr *data[],
 882                         struct netlink_ext_ack *extack)
 883 {
 884         bool is_can_fd = false;
 885
 886         /* Make sure that valid CAN FD configurations always consist of
 887          * - nominal/arbitration bittiming
 888          * - data bittiming
 889          * - control mode with CAN_CTRLMODE_FD set
 890          */
 891
 892         if (!data)
 893                 return 0;
 894
 895         if (data[IFLA_CAN_CTRLMODE]) {
 896                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 897
 898                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 899         }
 900
 901         if (is_can_fd) {
 902                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 903                         return -EOPNOTSUPP;
 904         }
 905
 906         if (data[IFLA_CAN_DATA_BITTIMING]) {
 907                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 908                         return -EOPNOTSUPP;
 909         }
 910
 911         return 0;
 912 }
 913
 914 static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 915                           struct nlattr *data[],
 916                           struct netlink_ext_ack *extack)
 917 {
 918         struct can_priv *priv = netdev_priv(dev);
 919         int err;
 920
 921         /* We need synchronization with dev->stop() */
 922         ASSERT_RTNL();
 923
 924         if (data[IFLA_CAN_BITTIMING]) {
 925                 struct can_bittiming bt;
 926
 927                 /* Do not allow changing bittiming while running */
 928                 if (dev->flags & IFF_UP)
 929                         return -EBUSY;
 930
 931                 /* Calculate bittiming parameters based on
 932                  * bittiming_const if set, otherwise pass bitrate
 933                  * directly via do_set_bitrate(). Bail out if neither
 934                  * is given.
 935                  */
 936                 if (!priv->bittiming_const && !priv->do_set_bittiming)
 937                         return -EOPNOTSUPP;
 938
 939                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 940                 err = can_get_bittiming(dev, &bt,
 941                                         priv->bittiming_const,
 942                                         priv->bitrate_const,
 943                                         priv->bitrate_const_cnt);
 944                 if (err)
 945                         return err;
 946                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 947
 948                 if (priv->do_set_bittiming) {
 949                         /* Finally, set the bit-timing registers */
 950                         err = priv->do_set_bittiming(dev);
 951                         if (err)
 952                                 return err;
 953                 }
 954         }
 955
 956         if (data[IFLA_CAN_CTRLMODE]) {
 957                 struct can_ctrlmode *cm;
 958                 u32 ctrlstatic;
 959                 u32 maskedflags;
 960
 961                 /* Do not allow changing controller mode while running */
 962                 if (dev->flags & IFF_UP)
 963                         return -EBUSY;
 964                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 965                 ctrlstatic = priv->ctrlmode_static;
 966                 maskedflags = cm->flags & cm->mask;
 967
 968                 /* check whether provided bits are allowed to be passed */
 969                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
 970                         return -EOPNOTSUPP;
 971
 972                 /* do not check for static fd-non-iso if 'fd' is disabled */
 973                 if (!(maskedflags & CAN_CTRLMODE_FD))
 974                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
 975
 976                 /* make sure static options are provided by configuration */
 977                 if ((maskedflags & ctrlstatic) != ctrlstatic)
 978                         return -EOPNOTSUPP;
 979
 980                 /* clear bits to be modified and copy the flag values */
 981                 priv->ctrlmode &= ~cm->mask;
 982                 priv->ctrlmode |= maskedflags;
 983
 984                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
 985                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
 986                         dev->mtu = CANFD_MTU;
 987                 else
 988                         dev->mtu = CAN_MTU;
 989         }
 990
 991         if (data[IFLA_CAN_RESTART_MS]) {
 992                 /* Do not allow changing restart delay while running */
 993                 if (dev->flags & IFF_UP)
 994                         return -EBUSY;
 995                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
 996         }
 997
 998         if (data[IFLA_CAN_RESTART]) {
 999                 /* Do not allow a restart while not running */
1000                 if (!(dev->flags & IFF_UP))
1001                         return -EINVAL;
1002                 err = can_restart_now(dev);
1003                 if (err)
1004                         return err;
1005         }
1006
1007         if (data[IFLA_CAN_DATA_BITTIMING]) {
1008                 struct can_bittiming dbt;
1009
1010                 /* Do not allow changing bittiming while running */
1011                 if (dev->flags & IFF_UP)
1012                         return -EBUSY;
1013
1014                 /* Calculate bittiming parameters based on
1015                  * data_bittiming_const if set, otherwise pass bitrate
1016                  * directly via do_set_bitrate(). Bail out if neither
1017                  * is given.
1018                  */
1019                 if (!priv->data_bittiming_const && !priv->do_set_data_bittiming)
1020                         return -EOPNOTSUPP;
1021
1022                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
1023                        sizeof(dbt));
1024                 err = can_get_bittiming(dev, &dbt,
1025                                         priv->data_bittiming_const,
1026                                         priv->data_bitrate_const,
1027                                         priv->data_bitrate_const_cnt);
1028                 if (err)
1029                         return err;
1030                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
1031
1032                 if (priv->do_set_data_bittiming) {
1033                         /* Finally, set the bit-timing registers */
1034                         err = priv->do_set_data_bittiming(dev);
1035                         if (err)
1036                                 return err;
1037                 }
1038         }
1039
1040         if (data[IFLA_CAN_TERMINATION]) {
1041                 const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]);
1042                 const unsigned int num_term = priv->termination_const_cnt;
1043                 unsigned int i;
1044
1045                 if (!priv->do_set_termination)
1046                         return -EOPNOTSUPP;
1047
1048                 /* check whether given value is supported by the interface */
1049                 for (i = 0; i < num_term; i++) {
1050                         if (termval == priv->termination_const[i])
1051                                 break;
1052                 }
1053                 if (i >= num_term)
1054                         return -EINVAL;
1055
1056                 /* Finally, set the termination value */
1057                 err = priv->do_set_termination(dev, termval);
1058                 if (err)
1059                         return err;
1060
1061                 priv->termination = termval;
1062         }
1063
1064         return 0;
1065 }
1066
1067 static size_t can_get_size(const struct net_device *dev)
1068 {
1069         struct can_priv *priv = netdev_priv(dev);
1070         size_t size = 0;
1071
1072         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
1073                 size += nla_total_size(sizeof(struct can_bittiming));
1074         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
1075                 size += nla_total_size(sizeof(struct can_bittiming_const));
1076         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
1077         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
1078         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
1079         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
1080         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
1081                 size += nla_total_size(sizeof(struct can_berr_counter));
1082         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
1083                 size += nla_total_size(sizeof(struct can_bittiming));
1084         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
1085                 size += nla_total_size(sizeof(struct can_bittiming_const));
1086         if (priv->termination_const) {
1087                 size += nla_total_size(sizeof(priv->termination));              /* IFLA_CAN_TERMINATION */
1088                 size += nla_total_size(sizeof(*priv->termination_const) *       /* IFLA_CAN_TERMINATION_CONST */
1089                                        priv->termination_const_cnt);
1090         }
1091         if (priv->bitrate_const)                                /* IFLA_CAN_BITRATE_CONST */
1092                 size += nla_total_size(sizeof(*priv->bitrate_const) *
1093                                        priv->bitrate_const_cnt);
1094         if (priv->data_bitrate_const)                           /* IFLA_CAN_DATA_BITRATE_CONST */
1095                 size += nla_total_size(sizeof(*priv->data_bitrate_const) *
1096                                        priv->data_bitrate_const_cnt);
1097
1098         return size;
1099 }
1100
1101 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
1102 {
1103         struct can_priv *priv = netdev_priv(dev);
1104         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
1105         struct can_berr_counter bec = { };
1106         enum can_state state = priv->state;
1107
1108         if (priv->do_get_state)
1109                 priv->do_get_state(dev, &state);
1110
1111         if ((priv->bittiming.bitrate &&
1112              nla_put(skb, IFLA_CAN_BITTIMING,
1113                      sizeof(priv->bittiming), &priv->bittiming)) ||
1114
1115             (priv->bittiming_const &&
1116              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1117                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1118
1119             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1120             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1121             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1122             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1123
1124             (priv->do_get_berr_counter &&
1125              !priv->do_get_berr_counter(dev, &bec) &&
1126              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1127
1128             (priv->data_bittiming.bitrate &&
1129              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1130                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1131
1132             (priv->data_bittiming_const &&
1133              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1134                      sizeof(*priv->data_bittiming_const),
1135                      priv->data_bittiming_const)) ||
1136
1137             (priv->termination_const &&
1138              (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||
1139               nla_put(skb, IFLA_CAN_TERMINATION_CONST,
1140                       sizeof(*priv->termination_const) *
1141                       priv->termination_const_cnt,
1142                       priv->termination_const))) ||
1143
1144             (priv->bitrate_const &&
1145              nla_put(skb, IFLA_CAN_BITRATE_CONST,
1146                      sizeof(*priv->bitrate_const) *
1147                      priv->bitrate_const_cnt,
1148                      priv->bitrate_const)) ||
1149
1150             (priv->data_bitrate_const &&
1151              nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
1152                      sizeof(*priv->data_bitrate_const) *
1153                      priv->data_bitrate_const_cnt,
1154                      priv->data_bitrate_const))
1155             )
1156
1157                 return -EMSGSIZE;
1158
1159         return 0;
1160 }
1161
1162 static size_t can_get_xstats_size(const struct net_device *dev)
1163 {
1164         return sizeof(struct can_device_stats);
1165 }
1166
1167 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1168 {
1169         struct can_priv *priv = netdev_priv(dev);
1170
1171         if (nla_put(skb, IFLA_INFO_XSTATS,
1172                     sizeof(priv->can_stats), &priv->can_stats))
1173                 goto nla_put_failure;
1174         return 0;
1175
1176 nla_put_failure:
1177         return -EMSGSIZE;
1178 }
1179
1180 static int can_newlink(struct net *src_net, struct net_device *dev,
1181                        struct nlattr *tb[], struct nlattr *data[],
1182                        struct netlink_ext_ack *extack)
1183 {
1184         return -EOPNOTSUPP;
1185 }
1186
1187 static void can_dellink(struct net_device *dev, struct list_head *head)
1188 {
1189         return;
1190 }
1191
1192 static struct rtnl_link_ops can_link_ops __read_mostly = {
1193         .kind           = "can",
1194         .netns_refund   = true,
1195         .maxtype        = IFLA_CAN_MAX,
1196         .policy         = can_policy,
1197         .setup          = can_setup,
1198         .validate       = can_validate,
1199         .newlink        = can_newlink,
1200         .changelink     = can_changelink,
1201         .dellink        = can_dellink,
1202         .get_size       = can_get_size,
1203         .fill_info      = can_fill_info,
1204         .get_xstats_size = can_get_xstats_size,
1205         .fill_xstats    = can_fill_xstats,
1206 };
1207
1208 /*
1209  * Register the CAN network device
1210  */
1211 int register_candev(struct net_device *dev)
1212 {
1213         struct can_priv *priv = netdev_priv(dev);
1214
1215         /* Ensure termination_const, termination_const_cnt and
1216          * do_set_termination consistency. All must be either set or
1217          * unset.
1218          */
1219         if ((!priv->termination_const != !priv->termination_const_cnt) ||
1220             (!priv->termination_const != !priv->do_set_termination))
1221                 return -EINVAL;
1222
1223         if (!priv->bitrate_const != !priv->bitrate_const_cnt)
1224                 return -EINVAL;
1225
1226         if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
1227                 return -EINVAL;
1228
1229         dev->rtnl_link_ops = &can_link_ops;
1230         netif_carrier_off(dev);
1231
1232         return register_netdev(dev);
1233 }
1234 EXPORT_SYMBOL_GPL(register_candev);
1235
1236 /*
1237  * Unregister the CAN network device
1238  */
1239 void unregister_candev(struct net_device *dev)
1240 {
1241         unregister_netdev(dev);
1242 }
1243 EXPORT_SYMBOL_GPL(unregister_candev);
1244
1245 /*
1246  * Test if a network device is a candev based device
1247  * and return the can_priv* if so.
1248  */
1249 struct can_priv *safe_candev_priv(struct net_device *dev)
1250 {
1251         if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1252                 return NULL;
1253
1254         return netdev_priv(dev);
1255 }
1256 EXPORT_SYMBOL_GPL(safe_candev_priv);
1257
1258 static __init int can_dev_init(void)
1259 {
1260         int err;
1261
1262         can_led_notifier_init();
1263
1264         err = rtnl_link_register(&can_link_ops);
1265         if (!err)
1266                 printk(KERN_INFO MOD_DESC "\n");
1267
1268         return err;
1269 }
1270 module_init(can_dev_init);
1271
1272 static __exit void can_dev_exit(void)
1273 {
1274         rtnl_link_unregister(&can_link_ops);
1275
1276         can_led_notifier_exit();
1277 }
1278 module_exit(can_dev_exit);
1279
1280 MODULE_ALIAS_RTNL_LINK("can");