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 <linux/of.h>
  31 #include <net/rtnetlink.h>
  32
  33 #define MOD_DESC "CAN device driver interface"
  34
  35 MODULE_DESCRIPTION(MOD_DESC);
  36 MODULE_LICENSE("GPL v2");
  37 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
  38
  39 /* CAN DLC to real data length conversion helpers */
  40
  41 static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
  42                              8, 12, 16, 20, 24, 32, 48, 64};
  43
  44 /* get data length from can_dlc with sanitized can_dlc */
  45 u8 can_dlc2len(u8 can_dlc)
  46 {
  47         return dlc2len[can_dlc & 0x0F];
  48 }
  49 EXPORT_SYMBOL_GPL(can_dlc2len);
  50
  51 static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,         /* 0 - 8 */
  52                              9, 9, 9, 9,                        /* 9 - 12 */
  53                              10, 10, 10, 10,                    /* 13 - 16 */
  54                              11, 11, 11, 11,                    /* 17 - 20 */
  55                              12, 12, 12, 12,                    /* 21 - 24 */
  56                              13, 13, 13, 13, 13, 13, 13, 13,    /* 25 - 32 */
  57                              14, 14, 14, 14, 14, 14, 14, 14,    /* 33 - 40 */
  58                              14, 14, 14, 14, 14, 14, 14, 14,    /* 41 - 48 */
  59                              15, 15, 15, 15, 15, 15, 15, 15,    /* 49 - 56 */
  60                              15, 15, 15, 15, 15, 15, 15, 15};   /* 57 - 64 */
  61
  62 /* map the sanitized data length to an appropriate data length code */
  63 u8 can_len2dlc(u8 len)
  64 {
  65         if (unlikely(len > 64))
  66                 return 0xF;
  67
  68         return len2dlc[len];
  69 }
  70 EXPORT_SYMBOL_GPL(can_len2dlc);
  71
  72 #ifdef CONFIG_CAN_CALC_BITTIMING
  73 #define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
  74 #define CAN_CALC_SYNC_SEG 1
  75
  76 /*
  77  * Bit-timing calculation derived from:
  78  *
  79  * Code based on LinCAN sources and H8S2638 project
  80  * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
  81  * Copyright 2005      Stanislav Marek
  82  * email: pisa@cmp.felk.cvut.cz
  83  *
  84  * Calculates proper bit-timing parameters for a specified bit-rate
  85  * and sample-point, which can then be used to set the bit-timing
  86  * registers of the CAN controller. You can find more information
  87  * in the header file linux/can/netlink.h.
  88  */
  89 static int can_update_sample_point(const struct can_bittiming_const *btc,
  90                           unsigned int sample_point_nominal, unsigned int tseg,
  91                           unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
  92                           unsigned int *sample_point_error_ptr)
  93 {
  94         unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
  95         unsigned int sample_point, best_sample_point = 0;
  96         unsigned int tseg1, tseg2;
  97         int i;
  98
  99         for (i = 0; i <= 1; i++) {
 100                 tseg2 = tseg + CAN_CALC_SYNC_SEG - (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) / 1000 - i;
 101                 tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
 102                 tseg1 = tseg - tseg2;
 103                 if (tseg1 > btc->tseg1_max) {
 104                         tseg1 = btc->tseg1_max;
 105                         tseg2 = tseg - tseg1;
 106                 }
 107
 108                 sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) / (tseg + CAN_CALC_SYNC_SEG);
 109                 sample_point_error = abs(sample_point_nominal - sample_point);
 110
 111                 if ((sample_point <= sample_point_nominal) && (sample_point_error < best_sample_point_error)) {
 112                         best_sample_point = sample_point;
 113                         best_sample_point_error = sample_point_error;
 114                         *tseg1_ptr = tseg1;
 115                         *tseg2_ptr = tseg2;
 116                 }
 117         }
 118
 119         if (sample_point_error_ptr)
 120                 *sample_point_error_ptr = best_sample_point_error;
 121
 122         return best_sample_point;
 123 }
 124
 125 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 126                               const struct can_bittiming_const *btc)
 127 {
 128         struct can_priv *priv = netdev_priv(dev);
 129         unsigned int bitrate;                   /* current bitrate */
 130         unsigned int bitrate_error;             /* difference between current and nominal value */
 131         unsigned int best_bitrate_error = UINT_MAX;
 132         unsigned int sample_point_error;        /* difference between current and nominal value */
 133         unsigned int best_sample_point_error = UINT_MAX;
 134         unsigned int sample_point_nominal;      /* nominal sample point */
 135         unsigned int best_tseg = 0;             /* current best value for tseg */
 136         unsigned int best_brp = 0;              /* current best value for brp */
 137         unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
 138         u64 v64;
 139
 140         /* Use CiA recommended sample points */
 141         if (bt->sample_point) {
 142                 sample_point_nominal = bt->sample_point;
 143         } else {
 144                 if (bt->bitrate > 800000)
 145                         sample_point_nominal = 750;
 146                 else if (bt->bitrate > 500000)
 147                         sample_point_nominal = 800;
 148                 else
 149                         sample_point_nominal = 875;
 150         }
 151
 152         /* tseg even = round down, odd = round up */
 153         for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
 154              tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
 155                 tsegall = CAN_CALC_SYNC_SEG + tseg / 2;
 156
 157                 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
 158                 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
 159
 160                 /* choose brp step which is possible in system */
 161                 brp = (brp / btc->brp_inc) * btc->brp_inc;
 162                 if ((brp < btc->brp_min) || (brp > btc->brp_max))
 163                         continue;
 164
 165                 bitrate = priv->clock.freq / (brp * tsegall);
 166                 bitrate_error = abs(bt->bitrate - bitrate);
 167
 168                 /* tseg brp biterror */
 169                 if (bitrate_error > best_bitrate_error)
 170                         continue;
 171
 172                 /* reset sample point error if we have a better bitrate */
 173                 if (bitrate_error < best_bitrate_error)
 174                         best_sample_point_error = UINT_MAX;
 175
 176                 can_update_sample_point(btc, sample_point_nominal, tseg / 2, &tseg1, &tseg2, &sample_point_error);
 177                 if (sample_point_error > best_sample_point_error)
 178                         continue;
 179
 180                 best_sample_point_error = sample_point_error;
 181                 best_bitrate_error = bitrate_error;
 182                 best_tseg = tseg / 2;
 183                 best_brp = brp;
 184
 185                 if (bitrate_error == 0 && sample_point_error == 0)
 186                         break;
 187         }
 188
 189         if (best_bitrate_error) {
 190                 /* Error in one-tenth of a percent */
 191                 v64 = (u64)best_bitrate_error * 1000;
 192                 do_div(v64, bt->bitrate);
 193                 bitrate_error = (u32)v64;
 194                 if (bitrate_error > CAN_CALC_MAX_ERROR) {
 195                         netdev_err(dev,
 196                                    "bitrate error %d.%d%% too high\n",
 197                                    bitrate_error / 10, bitrate_error % 10);
 198                         return -EDOM;
 199                 }
 200                 netdev_warn(dev, "bitrate error %d.%d%%\n",
 201                             bitrate_error / 10, bitrate_error % 10);
 202         }
 203
 204         /* real sample point */
 205         bt->sample_point = can_update_sample_point(btc, sample_point_nominal, best_tseg,
 206                                           &tseg1, &tseg2, NULL);
 207
 208         v64 = (u64)best_brp * 1000 * 1000 * 1000;
 209         do_div(v64, priv->clock.freq);
 210         bt->tq = (u32)v64;
 211         bt->prop_seg = tseg1 / 2;
 212         bt->phase_seg1 = tseg1 - bt->prop_seg;
 213         bt->phase_seg2 = tseg2;
 214
 215         /* check for sjw user settings */
 216         if (!bt->sjw || !btc->sjw_max) {
 217                 bt->sjw = 1;
 218         } else {
 219                 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
 220                 if (bt->sjw > btc->sjw_max)
 221                         bt->sjw = btc->sjw_max;
 222                 /* bt->sjw must not be higher than tseg2 */
 223                 if (tseg2 < bt->sjw)
 224                         bt->sjw = tseg2;
 225         }
 226
 227         bt->brp = best_brp;
 228
 229         /* real bitrate */
 230         bt->bitrate = priv->clock.freq / (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2));
 231
 232         return 0;
 233 }
 234 #else /* !CONFIG_CAN_CALC_BITTIMING */
 235 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 236                               const struct can_bittiming_const *btc)
 237 {
 238         netdev_err(dev, "bit-timing calculation not available\n");
 239         return -EINVAL;
 240 }
 241 #endif /* CONFIG_CAN_CALC_BITTIMING */
 242
 243 /*
 244  * Checks the validity of the specified bit-timing parameters prop_seg,
 245  * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
 246  * prescaler value brp. You can find more information in the header
 247  * file linux/can/netlink.h.
 248  */
 249 static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
 250                                const struct can_bittiming_const *btc)
 251 {
 252         struct can_priv *priv = netdev_priv(dev);
 253         int tseg1, alltseg;
 254         u64 brp64;
 255
 256         tseg1 = bt->prop_seg + bt->phase_seg1;
 257         if (!bt->sjw)
 258                 bt->sjw = 1;
 259         if (bt->sjw > btc->sjw_max ||
 260             tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
 261             bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
 262                 return -ERANGE;
 263
 264         brp64 = (u64)priv->clock.freq * (u64)bt->tq;
 265         if (btc->brp_inc > 1)
 266                 do_div(brp64, btc->brp_inc);
 267         brp64 += 500000000UL - 1;
 268         do_div(brp64, 1000000000UL); /* the practicable BRP */
 269         if (btc->brp_inc > 1)
 270                 brp64 *= btc->brp_inc;
 271         bt->brp = (u32)brp64;
 272
 273         if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
 274                 return -EINVAL;
 275
 276         alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
 277         bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
 278         bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
 279
 280         return 0;
 281 }
 282
 283 /* Checks the validity of predefined bitrate settings */
 284 static int can_validate_bitrate(struct net_device *dev, struct can_bittiming *bt,
 285                                 const u32 *bitrate_const,
 286                                 const unsigned int bitrate_const_cnt)
 287 {
 288         struct can_priv *priv = netdev_priv(dev);
 289         unsigned int i;
 290
 291         for (i = 0; i < bitrate_const_cnt; i++) {
 292                 if (bt->bitrate == bitrate_const[i])
 293                         break;
 294         }
 295
 296         if (i >= priv->bitrate_const_cnt)
 297                 return -EINVAL;
 298
 299         return 0;
 300 }
 301
 302 static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
 303                              const struct can_bittiming_const *btc,
 304                              const u32 *bitrate_const,
 305                              const unsigned int bitrate_const_cnt)
 306 {
 307         int err;
 308
 309         /*
 310          * Depending on the given can_bittiming parameter structure the CAN
 311          * timing parameters are calculated based on the provided bitrate OR
 312          * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
 313          * provided directly which are then checked and fixed up.
 314          */
 315         if (!bt->tq && bt->bitrate && btc)
 316                 err = can_calc_bittiming(dev, bt, btc);
 317         else if (bt->tq && !bt->bitrate && btc)
 318                 err = can_fixup_bittiming(dev, bt, btc);
 319         else if (!bt->tq && bt->bitrate && bitrate_const)
 320                 err = can_validate_bitrate(dev, bt, bitrate_const,
 321                                            bitrate_const_cnt);
 322         else
 323                 err = -EINVAL;
 324
 325         return err;
 326 }
 327
 328 static void can_update_state_error_stats(struct net_device *dev,
 329                                          enum can_state new_state)
 330 {
 331         struct can_priv *priv = netdev_priv(dev);
 332
 333         if (new_state <= priv->state)
 334                 return;
 335
 336         switch (new_state) {
 337         case CAN_STATE_ERROR_WARNING:
 338                 priv->can_stats.error_warning++;
 339                 break;
 340         case CAN_STATE_ERROR_PASSIVE:
 341                 priv->can_stats.error_passive++;
 342                 break;
 343         case CAN_STATE_BUS_OFF:
 344                 priv->can_stats.bus_off++;
 345                 break;
 346         default:
 347                 break;
 348         }
 349 }
 350
 351 static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
 352 {
 353         switch (state) {
 354         case CAN_STATE_ERROR_ACTIVE:
 355                 return CAN_ERR_CRTL_ACTIVE;
 356         case CAN_STATE_ERROR_WARNING:
 357                 return CAN_ERR_CRTL_TX_WARNING;
 358         case CAN_STATE_ERROR_PASSIVE:
 359                 return CAN_ERR_CRTL_TX_PASSIVE;
 360         default:
 361                 return 0;
 362         }
 363 }
 364
 365 static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
 366 {
 367         switch (state) {
 368         case CAN_STATE_ERROR_ACTIVE:
 369                 return CAN_ERR_CRTL_ACTIVE;
 370         case CAN_STATE_ERROR_WARNING:
 371                 return CAN_ERR_CRTL_RX_WARNING;
 372         case CAN_STATE_ERROR_PASSIVE:
 373                 return CAN_ERR_CRTL_RX_PASSIVE;
 374         default:
 375                 return 0;
 376         }
 377 }
 378
 379 void can_change_state(struct net_device *dev, struct can_frame *cf,
 380                       enum can_state tx_state, enum can_state rx_state)
 381 {
 382         struct can_priv *priv = netdev_priv(dev);
 383         enum can_state new_state = max(tx_state, rx_state);
 384
 385         if (unlikely(new_state == priv->state)) {
 386                 netdev_warn(dev, "%s: oops, state did not change", __func__);
 387                 return;
 388         }
 389
 390         netdev_dbg(dev, "New error state: %d\n", new_state);
 391
 392         can_update_state_error_stats(dev, new_state);
 393         priv->state = new_state;
 394
 395         if (!cf)
 396                 return;
 397
 398         if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
 399                 cf->can_id |= CAN_ERR_BUSOFF;
 400                 return;
 401         }
 402
 403         cf->can_id |= CAN_ERR_CRTL;
 404         cf->data[1] |= tx_state >= rx_state ?
 405                        can_tx_state_to_frame(dev, tx_state) : 0;
 406         cf->data[1] |= tx_state <= rx_state ?
 407                        can_rx_state_to_frame(dev, rx_state) : 0;
 408 }
 409 EXPORT_SYMBOL_GPL(can_change_state);
 410
 411 /*
 412  * Local echo of CAN messages
 413  *
 414  * CAN network devices *should* support a local echo functionality
 415  * (see Documentation/networking/can.rst). To test the handling of CAN
 416  * interfaces that do not support the local echo both driver types are
 417  * implemented. In the case that the driver does not support the echo
 418  * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
 419  * to perform the echo as a fallback solution.
 420  */
 421 static void can_flush_echo_skb(struct net_device *dev)
 422 {
 423         struct can_priv *priv = netdev_priv(dev);
 424         struct net_device_stats *stats = &dev->stats;
 425         int i;
 426
 427         for (i = 0; i < priv->echo_skb_max; i++) {
 428                 if (priv->echo_skb[i]) {
 429                         kfree_skb(priv->echo_skb[i]);
 430                         priv->echo_skb[i] = NULL;
 431                         stats->tx_dropped++;
 432                         stats->tx_aborted_errors++;
 433                 }
 434         }
 435 }
 436
 437 /*
 438  * Put the skb on the stack to be looped backed locally lateron
 439  *
 440  * The function is typically called in the start_xmit function
 441  * of the device driver. The driver must protect access to
 442  * priv->echo_skb, if necessary.
 443  */
 444 void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 445                       unsigned int idx)
 446 {
 447         struct can_priv *priv = netdev_priv(dev);
 448
 449         BUG_ON(idx >= priv->echo_skb_max);
 450
 451         /* check flag whether this packet has to be looped back */
 452         if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
 453             (skb->protocol != htons(ETH_P_CAN) &&
 454              skb->protocol != htons(ETH_P_CANFD))) {
 455                 kfree_skb(skb);
 456                 return;
 457         }
 458
 459         if (!priv->echo_skb[idx]) {
 460
 461                 skb = can_create_echo_skb(skb);
 462                 if (!skb)
 463                         return;
 464
 465                 /* make settings for echo to reduce code in irq context */
 466                 skb->pkt_type = PACKET_BROADCAST;
 467                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 468                 skb->dev = dev;
 469
 470                 /* save this skb for tx interrupt echo handling */
 471                 priv->echo_skb[idx] = skb;
 472         } else {
 473                 /* locking problem with netif_stop_queue() ?? */
 474                 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
 475                 kfree_skb(skb);
 476         }
 477 }
 478 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 479
 480 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
 481 {
 482         struct can_priv *priv = netdev_priv(dev);
 483
 484         BUG_ON(idx >= priv->echo_skb_max);
 485
 486         if (priv->echo_skb[idx]) {
 487                 struct sk_buff *skb = priv->echo_skb[idx];
 488                 struct can_frame *cf = (struct can_frame *)skb->data;
 489                 u8 dlc = cf->can_dlc;
 490
 491                 *len_ptr = dlc;
 492                 priv->echo_skb[idx] = NULL;
 493
 494                 return skb;
 495         }
 496
 497         return NULL;
 498 }
 499
 500 /*
 501  * Get the skb from the stack and loop it back locally
 502  *
 503  * The function is typically called when the TX done interrupt
 504  * is handled in the device driver. The driver must protect
 505  * access to priv->echo_skb, if necessary.
 506  */
 507 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 508 {
 509         struct sk_buff *skb;
 510         u8 len;
 511
 512         skb = __can_get_echo_skb(dev, idx, &len);
 513         if (!skb)
 514                 return 0;
 515
 516         netif_rx(skb);
 517
 518         return len;
 519 }
 520 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 521
 522 /*
 523   * Remove the skb from the stack and free it.
 524   *
 525   * The function is typically called when TX failed.
 526   */
 527 void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 528 {
 529         struct can_priv *priv = netdev_priv(dev);
 530
 531         BUG_ON(idx >= priv->echo_skb_max);
 532
 533         if (priv->echo_skb[idx]) {
 534                 dev_kfree_skb_any(priv->echo_skb[idx]);
 535                 priv->echo_skb[idx] = NULL;
 536         }
 537 }
 538 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 539
 540 /*
 541  * CAN device restart for bus-off recovery
 542  */
 543 static void can_restart(struct net_device *dev)
 544 {
 545         struct can_priv *priv = netdev_priv(dev);
 546         struct net_device_stats *stats = &dev->stats;
 547         struct sk_buff *skb;
 548         struct can_frame *cf;
 549         int err;
 550
 551         BUG_ON(netif_carrier_ok(dev));
 552
 553         /*
 554          * No synchronization needed because the device is bus-off and
 555          * no messages can come in or go out.
 556          */
 557         can_flush_echo_skb(dev);
 558
 559         /* send restart message upstream */
 560         skb = alloc_can_err_skb(dev, &cf);
 561         if (skb == NULL) {
 562                 err = -ENOMEM;
 563                 goto restart;
 564         }
 565         cf->can_id |= CAN_ERR_RESTARTED;
 566
 567         netif_rx(skb);
 568
 569         stats->rx_packets++;
 570         stats->rx_bytes += cf->can_dlc;
 571
 572 restart:
 573         netdev_dbg(dev, "restarted\n");
 574         priv->can_stats.restarts++;
 575
 576         /* Now restart the device */
 577         err = priv->do_set_mode(dev, CAN_MODE_START);
 578
 579         netif_carrier_on(dev);
 580         if (err)
 581                 netdev_err(dev, "Error %d during restart", err);
 582 }
 583
 584 static void can_restart_work(struct work_struct *work)
 585 {
 586         struct delayed_work *dwork = to_delayed_work(work);
 587         struct can_priv *priv = container_of(dwork, struct can_priv, restart_work);
 588
 589         can_restart(priv->dev);
 590 }
 591
 592 int can_restart_now(struct net_device *dev)
 593 {
 594         struct can_priv *priv = netdev_priv(dev);
 595
 596         /*
 597          * A manual restart is only permitted if automatic restart is
 598          * disabled and the device is in the bus-off state
 599          */
 600         if (priv->restart_ms)
 601                 return -EINVAL;
 602         if (priv->state != CAN_STATE_BUS_OFF)
 603                 return -EBUSY;
 604
 605         cancel_delayed_work_sync(&priv->restart_work);
 606         can_restart(dev);
 607
 608         return 0;
 609 }
 610
 611 /*
 612  * CAN bus-off
 613  *
 614  * This functions should be called when the device goes bus-off to
 615  * tell the netif layer that no more packets can be sent or received.
 616  * If enabled, a timer is started to trigger bus-off recovery.
 617  */
 618 void can_bus_off(struct net_device *dev)
 619 {
 620         struct can_priv *priv = netdev_priv(dev);
 621
 622         netdev_info(dev, "bus-off\n");
 623
 624         netif_carrier_off(dev);
 625
 626         if (priv->restart_ms)
 627                 schedule_delayed_work(&priv->restart_work,
 628                                       msecs_to_jiffies(priv->restart_ms));
 629 }
 630 EXPORT_SYMBOL_GPL(can_bus_off);
 631
 632 static void can_setup(struct net_device *dev)
 633 {
 634         dev->type = ARPHRD_CAN;
 635         dev->mtu = CAN_MTU;
 636         dev->hard_header_len = 0;
 637         dev->addr_len = 0;
 638         dev->tx_queue_len = 10;
 639
 640         /* New-style flags. */
 641         dev->flags = IFF_NOARP;
 642         dev->features = NETIF_F_HW_CSUM;
 643 }
 644
 645 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 646 {
 647         struct sk_buff *skb;
 648
 649         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 650                                sizeof(struct can_frame));
 651         if (unlikely(!skb))
 652                 return NULL;
 653
 654         skb->protocol = htons(ETH_P_CAN);
 655         skb->pkt_type = PACKET_BROADCAST;
 656         skb->ip_summed = CHECKSUM_UNNECESSARY;
 657
 658         skb_reset_mac_header(skb);
 659         skb_reset_network_header(skb);
 660         skb_reset_transport_header(skb);
 661
 662         can_skb_reserve(skb);
 663         can_skb_prv(skb)->ifindex = dev->ifindex;
 664         can_skb_prv(skb)->skbcnt = 0;
 665
 666         *cf = skb_put_zero(skb, sizeof(struct can_frame));
 667
 668         return skb;
 669 }
 670 EXPORT_SYMBOL_GPL(alloc_can_skb);
 671
 672 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 673                                 struct canfd_frame **cfd)
 674 {
 675         struct sk_buff *skb;
 676
 677         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 678                                sizeof(struct canfd_frame));
 679         if (unlikely(!skb))
 680                 return NULL;
 681
 682         skb->protocol = htons(ETH_P_CANFD);
 683         skb->pkt_type = PACKET_BROADCAST;
 684         skb->ip_summed = CHECKSUM_UNNECESSARY;
 685
 686         skb_reset_mac_header(skb);
 687         skb_reset_network_header(skb);
 688         skb_reset_transport_header(skb);
 689
 690         can_skb_reserve(skb);
 691         can_skb_prv(skb)->ifindex = dev->ifindex;
 692         can_skb_prv(skb)->skbcnt = 0;
 693
 694         *cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
 695
 696         return skb;
 697 }
 698 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 699
 700 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 701 {
 702         struct sk_buff *skb;
 703
 704         skb = alloc_can_skb(dev, cf);
 705         if (unlikely(!skb))
 706                 return NULL;
 707
 708         (*cf)->can_id = CAN_ERR_FLAG;
 709         (*cf)->can_dlc = CAN_ERR_DLC;
 710
 711         return skb;
 712 }
 713 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 714
 715 /*
 716  * Allocate and setup space for the CAN network device
 717  */
 718 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
 719                                     unsigned int txqs, unsigned int rxqs)
 720 {
 721         struct net_device *dev;
 722         struct can_priv *priv;
 723         int size;
 724
 725         if (echo_skb_max)
 726                 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
 727                         echo_skb_max * sizeof(struct sk_buff *);
 728         else
 729                 size = sizeof_priv;
 730
 731         dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup,
 732                                txqs, rxqs);
 733         if (!dev)
 734                 return NULL;
 735
 736         priv = netdev_priv(dev);
 737         priv->dev = dev;
 738
 739         if (echo_skb_max) {
 740                 priv->echo_skb_max = echo_skb_max;
 741                 priv->echo_skb = (void *)priv +
 742                         ALIGN(sizeof_priv, sizeof(struct sk_buff *));
 743         }
 744
 745         priv->state = CAN_STATE_STOPPED;
 746
 747         INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
 748
 749         return dev;
 750 }
 751 EXPORT_SYMBOL_GPL(alloc_candev_mqs);
 752
 753 /*
 754  * Free space of the CAN network device
 755  */
 756 void free_candev(struct net_device *dev)
 757 {
 758         free_netdev(dev);
 759 }
 760 EXPORT_SYMBOL_GPL(free_candev);
 761
 762 /*
 763  * changing MTU and control mode for CAN/CANFD devices
 764  */
 765 int can_change_mtu(struct net_device *dev, int new_mtu)
 766 {
 767         struct can_priv *priv = netdev_priv(dev);
 768
 769         /* Do not allow changing the MTU while running */
 770         if (dev->flags & IFF_UP)
 771                 return -EBUSY;
 772
 773         /* allow change of MTU according to the CANFD ability of the device */
 774         switch (new_mtu) {
 775         case CAN_MTU:
 776                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 777                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 778                         return -EINVAL;
 779
 780                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 781                 break;
 782
 783         case CANFD_MTU:
 784                 /* check for potential CANFD ability */
 785                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 786                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 787                         return -EINVAL;
 788
 789                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 790                 break;
 791
 792         default:
 793                 return -EINVAL;
 794         }
 795
 796         dev->mtu = new_mtu;
 797         return 0;
 798 }
 799 EXPORT_SYMBOL_GPL(can_change_mtu);
 800
 801 /*
 802  * Common open function when the device gets opened.
 803  *
 804  * This function should be called in the open function of the device
 805  * driver.
 806  */
 807 int open_candev(struct net_device *dev)
 808 {
 809         struct can_priv *priv = netdev_priv(dev);
 810
 811         if (!priv->bittiming.bitrate) {
 812                 netdev_err(dev, "bit-timing not yet defined\n");
 813                 return -EINVAL;
 814         }
 815
 816         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 817         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 818             (!priv->data_bittiming.bitrate ||
 819              (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
 820                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 821                 return -EINVAL;
 822         }
 823
 824         /* Switch carrier on if device was stopped while in bus-off state */
 825         if (!netif_carrier_ok(dev))
 826                 netif_carrier_on(dev);
 827
 828         return 0;
 829 }
 830 EXPORT_SYMBOL_GPL(open_candev);
 831
 832 #ifdef CONFIG_OF
 833 /* Common function that can be used to understand the limitation of
 834  * a transceiver when it provides no means to determine these limitations
 835  * at runtime.
 836  */
 837 void of_can_transceiver(struct net_device *dev)
 838 {
 839         struct device_node *dn;
 840         struct can_priv *priv = netdev_priv(dev);
 841         struct device_node *np = dev->dev.parent->of_node;
 842         int ret;
 843
 844         dn = of_get_child_by_name(np, "can-transceiver");
 845         if (!dn)
 846                 return;
 847
 848         ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max);
 849         if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
 850                 netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
 851 }
 852 EXPORT_SYMBOL_GPL(of_can_transceiver);
 853 #endif
 854
 855 /*
 856  * Common close function for cleanup before the device gets closed.
 857  *
 858  * This function should be called in the close function of the device
 859  * driver.
 860  */
 861 void close_candev(struct net_device *dev)
 862 {
 863         struct can_priv *priv = netdev_priv(dev);
 864
 865         cancel_delayed_work_sync(&priv->restart_work);
 866         can_flush_echo_skb(dev);
 867 }
 868 EXPORT_SYMBOL_GPL(close_candev);
 869
 870 /*
 871  * CAN netlink interface
 872  */
 873 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 874         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 875         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 876         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 877         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 878         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 879         [IFLA_CAN_BITTIMING_CONST]
 880                                 = { .len = sizeof(struct can_bittiming_const) },
 881         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 882         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 883         [IFLA_CAN_DATA_BITTIMING]
 884                                 = { .len = sizeof(struct can_bittiming) },
 885         [IFLA_CAN_DATA_BITTIMING_CONST]
 886                                 = { .len = sizeof(struct can_bittiming_const) },
 887 };
 888
 889 static int can_validate(struct nlattr *tb[], struct nlattr *data[],
 890                         struct netlink_ext_ack *extack)
 891 {
 892         bool is_can_fd = false;
 893
 894         /* Make sure that valid CAN FD configurations always consist of
 895          * - nominal/arbitration bittiming
 896          * - data bittiming
 897          * - control mode with CAN_CTRLMODE_FD set
 898          */
 899
 900         if (!data)
 901                 return 0;
 902
 903         if (data[IFLA_CAN_CTRLMODE]) {
 904                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 905
 906                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 907         }
 908
 909         if (is_can_fd) {
 910                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 911                         return -EOPNOTSUPP;
 912         }
 913
 914         if (data[IFLA_CAN_DATA_BITTIMING]) {
 915                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 916                         return -EOPNOTSUPP;
 917         }
 918
 919         return 0;
 920 }
 921
 922 static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 923                           struct nlattr *data[],
 924                           struct netlink_ext_ack *extack)
 925 {
 926         struct can_priv *priv = netdev_priv(dev);
 927         int err;
 928
 929         /* We need synchronization with dev->stop() */
 930         ASSERT_RTNL();
 931
 932         if (data[IFLA_CAN_BITTIMING]) {
 933                 struct can_bittiming bt;
 934
 935                 /* Do not allow changing bittiming while running */
 936                 if (dev->flags & IFF_UP)
 937                         return -EBUSY;
 938
 939                 /* Calculate bittiming parameters based on
 940                  * bittiming_const if set, otherwise pass bitrate
 941                  * directly via do_set_bitrate(). Bail out if neither
 942                  * is given.
 943                  */
 944                 if (!priv->bittiming_const && !priv->do_set_bittiming)
 945                         return -EOPNOTSUPP;
 946
 947                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 948                 err = can_get_bittiming(dev, &bt,
 949                                         priv->bittiming_const,
 950                                         priv->bitrate_const,
 951                                         priv->bitrate_const_cnt);
 952                 if (err)
 953                         return err;
 954
 955                 if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) {
 956                         netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n",
 957                                    priv->bitrate_max);
 958                         return -EINVAL;
 959                 }
 960
 961                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 962
 963                 if (priv->do_set_bittiming) {
 964                         /* Finally, set the bit-timing registers */
 965                         err = priv->do_set_bittiming(dev);
 966                         if (err)
 967                                 return err;
 968                 }
 969         }
 970
 971         if (data[IFLA_CAN_CTRLMODE]) {
 972                 struct can_ctrlmode *cm;
 973                 u32 ctrlstatic;
 974                 u32 maskedflags;
 975
 976                 /* Do not allow changing controller mode while running */
 977                 if (dev->flags & IFF_UP)
 978                         return -EBUSY;
 979                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 980                 ctrlstatic = priv->ctrlmode_static;
 981                 maskedflags = cm->flags & cm->mask;
 982
 983                 /* check whether provided bits are allowed to be passed */
 984                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
 985                         return -EOPNOTSUPP;
 986
 987                 /* do not check for static fd-non-iso if 'fd' is disabled */
 988                 if (!(maskedflags & CAN_CTRLMODE_FD))
 989                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
 990
 991                 /* make sure static options are provided by configuration */
 992                 if ((maskedflags & ctrlstatic) != ctrlstatic)
 993                         return -EOPNOTSUPP;
 994
 995                 /* clear bits to be modified and copy the flag values */
 996                 priv->ctrlmode &= ~cm->mask;
 997                 priv->ctrlmode |= maskedflags;
 998
 999                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
1000                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
1001                         dev->mtu = CANFD_MTU;
1002                 else
1003                         dev->mtu = CAN_MTU;
1004         }
1005
1006         if (data[IFLA_CAN_RESTART_MS]) {
1007                 /* Do not allow changing restart delay while running */
1008                 if (dev->flags & IFF_UP)
1009                         return -EBUSY;
1010                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
1011         }
1012
1013         if (data[IFLA_CAN_RESTART]) {
1014                 /* Do not allow a restart while not running */
1015                 if (!(dev->flags & IFF_UP))
1016                         return -EINVAL;
1017                 err = can_restart_now(dev);
1018                 if (err)
1019                         return err;
1020         }
1021
1022         if (data[IFLA_CAN_DATA_BITTIMING]) {
1023                 struct can_bittiming dbt;
1024
1025                 /* Do not allow changing bittiming while running */
1026                 if (dev->flags & IFF_UP)
1027                         return -EBUSY;
1028
1029                 /* Calculate bittiming parameters based on
1030                  * data_bittiming_const if set, otherwise pass bitrate
1031                  * directly via do_set_bitrate(). Bail out if neither
1032                  * is given.
1033                  */
1034                 if (!priv->data_bittiming_const && !priv->do_set_data_bittiming)
1035                         return -EOPNOTSUPP;
1036
1037                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
1038                        sizeof(dbt));
1039                 err = can_get_bittiming(dev, &dbt,
1040                                         priv->data_bittiming_const,
1041                                         priv->data_bitrate_const,
1042                                         priv->data_bitrate_const_cnt);
1043                 if (err)
1044                         return err;
1045
1046                 if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
1047                         netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
1048                                    priv->bitrate_max);
1049                         return -EINVAL;
1050                 }
1051
1052                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
1053
1054                 if (priv->do_set_data_bittiming) {
1055                         /* Finally, set the bit-timing registers */
1056                         err = priv->do_set_data_bittiming(dev);
1057                         if (err)
1058                                 return err;
1059                 }
1060         }
1061
1062         if (data[IFLA_CAN_TERMINATION]) {
1063                 const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]);
1064                 const unsigned int num_term = priv->termination_const_cnt;
1065                 unsigned int i;
1066
1067                 if (!priv->do_set_termination)
1068                         return -EOPNOTSUPP;
1069
1070                 /* check whether given value is supported by the interface */
1071                 for (i = 0; i < num_term; i++) {
1072                         if (termval == priv->termination_const[i])
1073                                 break;
1074                 }
1075                 if (i >= num_term)
1076                         return -EINVAL;
1077
1078                 /* Finally, set the termination value */
1079                 err = priv->do_set_termination(dev, termval);
1080                 if (err)
1081                         return err;
1082
1083                 priv->termination = termval;
1084         }
1085
1086         return 0;
1087 }
1088
1089 static size_t can_get_size(const struct net_device *dev)
1090 {
1091         struct can_priv *priv = netdev_priv(dev);
1092         size_t size = 0;
1093
1094         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
1095                 size += nla_total_size(sizeof(struct can_bittiming));
1096         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
1097                 size += nla_total_size(sizeof(struct can_bittiming_const));
1098         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
1099         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
1100         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
1101         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
1102         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
1103                 size += nla_total_size(sizeof(struct can_berr_counter));
1104         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
1105                 size += nla_total_size(sizeof(struct can_bittiming));
1106         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
1107                 size += nla_total_size(sizeof(struct can_bittiming_const));
1108         if (priv->termination_const) {
1109                 size += nla_total_size(sizeof(priv->termination));              /* IFLA_CAN_TERMINATION */
1110                 size += nla_total_size(sizeof(*priv->termination_const) *       /* IFLA_CAN_TERMINATION_CONST */
1111                                        priv->termination_const_cnt);
1112         }
1113         if (priv->bitrate_const)                                /* IFLA_CAN_BITRATE_CONST */
1114                 size += nla_total_size(sizeof(*priv->bitrate_const) *
1115                                        priv->bitrate_const_cnt);
1116         if (priv->data_bitrate_const)                           /* IFLA_CAN_DATA_BITRATE_CONST */
1117                 size += nla_total_size(sizeof(*priv->data_bitrate_const) *
1118                                        priv->data_bitrate_const_cnt);
1119         size += sizeof(priv->bitrate_max);                      /* IFLA_CAN_BITRATE_MAX */
1120
1121         return size;
1122 }
1123
1124 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
1125 {
1126         struct can_priv *priv = netdev_priv(dev);
1127         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
1128         struct can_berr_counter bec;
1129         enum can_state state = priv->state;
1130
1131         if (priv->do_get_state)
1132                 priv->do_get_state(dev, &state);
1133
1134         if ((priv->bittiming.bitrate &&
1135              nla_put(skb, IFLA_CAN_BITTIMING,
1136                      sizeof(priv->bittiming), &priv->bittiming)) ||
1137
1138             (priv->bittiming_const &&
1139              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1140                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1141
1142             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1143             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1144             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1145             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1146
1147             (priv->do_get_berr_counter &&
1148              !priv->do_get_berr_counter(dev, &bec) &&
1149              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1150
1151             (priv->data_bittiming.bitrate &&
1152              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1153                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1154
1155             (priv->data_bittiming_const &&
1156              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1157                      sizeof(*priv->data_bittiming_const),
1158                      priv->data_bittiming_const)) ||
1159
1160             (priv->termination_const &&
1161              (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||
1162               nla_put(skb, IFLA_CAN_TERMINATION_CONST,
1163                       sizeof(*priv->termination_const) *
1164                       priv->termination_const_cnt,
1165                       priv->termination_const))) ||
1166
1167             (priv->bitrate_const &&
1168              nla_put(skb, IFLA_CAN_BITRATE_CONST,
1169                      sizeof(*priv->bitrate_const) *
1170                      priv->bitrate_const_cnt,
1171                      priv->bitrate_const)) ||
1172
1173             (priv->data_bitrate_const &&
1174              nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
1175                      sizeof(*priv->data_bitrate_const) *
1176                      priv->data_bitrate_const_cnt,
1177                      priv->data_bitrate_const)) ||
1178
1179             (nla_put(skb, IFLA_CAN_BITRATE_MAX,
1180                      sizeof(priv->bitrate_max),
1181                      &priv->bitrate_max))
1182             )
1183
1184                 return -EMSGSIZE;
1185
1186         return 0;
1187 }
1188
1189 static size_t can_get_xstats_size(const struct net_device *dev)
1190 {
1191         return sizeof(struct can_device_stats);
1192 }
1193
1194 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1195 {
1196         struct can_priv *priv = netdev_priv(dev);
1197
1198         if (nla_put(skb, IFLA_INFO_XSTATS,
1199                     sizeof(priv->can_stats), &priv->can_stats))
1200                 goto nla_put_failure;
1201         return 0;
1202
1203 nla_put_failure:
1204         return -EMSGSIZE;
1205 }
1206
1207 static int can_newlink(struct net *src_net, struct net_device *dev,
1208                        struct nlattr *tb[], struct nlattr *data[],
1209                        struct netlink_ext_ack *extack)
1210 {
1211         return -EOPNOTSUPP;
1212 }
1213
1214 static void can_dellink(struct net_device *dev, struct list_head *head)
1215 {
1216         return;
1217 }
1218
1219 static struct rtnl_link_ops can_link_ops __read_mostly = {
1220         .kind           = "can",
1221         .maxtype        = IFLA_CAN_MAX,
1222         .policy         = can_policy,
1223         .setup          = can_setup,
1224         .validate       = can_validate,
1225         .newlink        = can_newlink,
1226         .changelink     = can_changelink,
1227         .dellink        = can_dellink,
1228         .get_size       = can_get_size,
1229         .fill_info      = can_fill_info,
1230         .get_xstats_size = can_get_xstats_size,
1231         .fill_xstats    = can_fill_xstats,
1232 };
1233
1234 /*
1235  * Register the CAN network device
1236  */
1237 int register_candev(struct net_device *dev)
1238 {
1239         struct can_priv *priv = netdev_priv(dev);
1240
1241         /* Ensure termination_const, termination_const_cnt and
1242          * do_set_termination consistency. All must be either set or
1243          * unset.
1244          */
1245         if ((!priv->termination_const != !priv->termination_const_cnt) ||
1246             (!priv->termination_const != !priv->do_set_termination))
1247                 return -EINVAL;
1248
1249         if (!priv->bitrate_const != !priv->bitrate_const_cnt)
1250                 return -EINVAL;
1251
1252         if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
1253                 return -EINVAL;
1254
1255         dev->rtnl_link_ops = &can_link_ops;
1256         return register_netdev(dev);
1257 }
1258 EXPORT_SYMBOL_GPL(register_candev);
1259
1260 /*
1261  * Unregister the CAN network device
1262  */
1263 void unregister_candev(struct net_device *dev)
1264 {
1265         unregister_netdev(dev);
1266 }
1267 EXPORT_SYMBOL_GPL(unregister_candev);
1268
1269 /*
1270  * Test if a network device is a candev based device
1271  * and return the can_priv* if so.
1272  */
1273 struct can_priv *safe_candev_priv(struct net_device *dev)
1274 {
1275         if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1276                 return NULL;
1277
1278         return netdev_priv(dev);
1279 }
1280 EXPORT_SYMBOL_GPL(safe_candev_priv);
1281
1282 static __init int can_dev_init(void)
1283 {
1284         int err;
1285
1286         can_led_notifier_init();
1287
1288         err = rtnl_link_register(&can_link_ops);
1289         if (!err)
1290                 printk(KERN_INFO MOD_DESC "\n");
1291
1292         return err;
1293 }
1294 module_init(can_dev_init);
1295
1296 static __exit void can_dev_exit(void)
1297 {
1298         rtnl_link_unregister(&can_link_ops);
1299
1300         can_led_notifier_exit();
1301 }
1302 module_exit(can_dev_exit);
1303
1304 MODULE_ALIAS_RTNL_LINK("can");