linux/drivers/net/can/dev.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
   4 * Copyright (C) 2006 Andrey Volkov, Varma Electronics
   5 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
   6 */
   7
   8#include <linux/module.h>
   9#include <linux/kernel.h>
  10#include <linux/slab.h>
  11#include <linux/netdevice.h>
  12#include <linux/if_arp.h>
  13#include <linux/workqueue.h>
  14#include <linux/can.h>
  15#include <linux/can/dev.h>
  16#include <linux/can/skb.h>
  17#include <linux/can/netlink.h>
  18#include <linux/can/led.h>
  19#include <linux/of.h>
  20#include <net/rtnetlink.h>
  21
  22#define MOD_DESC "CAN device driver interface"
  23
  24MODULE_DESCRIPTION(MOD_DESC);
  25MODULE_LICENSE("GPL v2");
  26MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
  27
  28/* CAN DLC to real data length conversion helpers */
  29
  30static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
  31                             8, 12, 16, 20, 24, 32, 48, 64};
  32
  33/* get data length from can_dlc with sanitized can_dlc */
  34u8 can_dlc2len(u8 can_dlc)
  35{
  36        return dlc2len[can_dlc & 0x0F];
  37}
  38EXPORT_SYMBOL_GPL(can_dlc2len);
  39
  40static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,         /* 0 - 8 */
  41                             9, 9, 9, 9,                        /* 9 - 12 */
  42                             10, 10, 10, 10,                    /* 13 - 16 */
  43                             11, 11, 11, 11,                    /* 17 - 20 */
  44                             12, 12, 12, 12,                    /* 21 - 24 */
  45                             13, 13, 13, 13, 13, 13, 13, 13,    /* 25 - 32 */
  46                             14, 14, 14, 14, 14, 14, 14, 14,    /* 33 - 40 */
  47                             14, 14, 14, 14, 14, 14, 14, 14,    /* 41 - 48 */
  48                             15, 15, 15, 15, 15, 15, 15, 15,    /* 49 - 56 */
  49                             15, 15, 15, 15, 15, 15, 15, 15};   /* 57 - 64 */
  50
  51/* map the sanitized data length to an appropriate data length code */
  52u8 can_len2dlc(u8 len)
  53{
  54        if (unlikely(len > 64))
  55                return 0xF;
  56
  57        return len2dlc[len];
  58}
  59EXPORT_SYMBOL_GPL(can_len2dlc);
  60
  61#ifdef CONFIG_CAN_CALC_BITTIMING
  62#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
  63#define CAN_CALC_SYNC_SEG 1
  64
  65/*
  66 * Bit-timing calculation derived from:
  67 *
  68 * Code based on LinCAN sources and H8S2638 project
  69 * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
  70 * Copyright 2005      Stanislav Marek
  71 * email: pisa@cmp.felk.cvut.cz
  72 *
  73 * Calculates proper bit-timing parameters for a specified bit-rate
  74 * and sample-point, which can then be used to set the bit-timing
  75 * registers of the CAN controller. You can find more information
  76 * in the header file linux/can/netlink.h.
  77 */
  78static int can_update_sample_point(const struct can_bittiming_const *btc,
  79                          unsigned int sample_point_nominal, unsigned int tseg,
  80                          unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
  81                          unsigned int *sample_point_error_ptr)
  82{
  83        unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
  84        unsigned int sample_point, best_sample_point = 0;
  85        unsigned int tseg1, tseg2;
  86        int i;
  87
  88        for (i = 0; i <= 1; i++) {
  89                tseg2 = tseg + CAN_CALC_SYNC_SEG - (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) / 1000 - i;
  90                tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
  91                tseg1 = tseg - tseg2;
  92                if (tseg1 > btc->tseg1_max) {
  93                        tseg1 = btc->tseg1_max;
  94                        tseg2 = tseg - tseg1;
  95                }
  96
  97                sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) / (tseg + CAN_CALC_SYNC_SEG);
  98                sample_point_error = abs(sample_point_nominal - sample_point);
  99
 100                if ((sample_point <= sample_point_nominal) && (sample_point_error < best_sample_point_error)) {
 101                        best_sample_point = sample_point;
 102                        best_sample_point_error = sample_point_error;
 103                        *tseg1_ptr = tseg1;
 104                        *tseg2_ptr = tseg2;
 105                }
 106        }
 107
 108        if (sample_point_error_ptr)
 109                *sample_point_error_ptr = best_sample_point_error;
 110
 111        return best_sample_point;
 112}
 113
 114static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 115                              const struct can_bittiming_const *btc)
 116{
 117        struct can_priv *priv = netdev_priv(dev);
 118        unsigned int bitrate;                   /* current bitrate */
 119        unsigned int bitrate_error;             /* difference between current and nominal value */
 120        unsigned int best_bitrate_error = UINT_MAX;
 121        unsigned int sample_point_error;        /* difference between current and nominal value */
 122        unsigned int best_sample_point_error = UINT_MAX;
 123        unsigned int sample_point_nominal;      /* nominal sample point */
 124        unsigned int best_tseg = 0;             /* current best value for tseg */
 125        unsigned int best_brp = 0;              /* current best value for brp */
 126        unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
 127        u64 v64;
 128
 129        /* Use CiA recommended sample points */
 130        if (bt->sample_point) {
 131                sample_point_nominal = bt->sample_point;
 132        } else {
 133                if (bt->bitrate > 800000)
 134                        sample_point_nominal = 750;
 135                else if (bt->bitrate > 500000)
 136                        sample_point_nominal = 800;
 137                else
 138                        sample_point_nominal = 875;
 139        }
 140
 141        /* tseg even = round down, odd = round up */
 142        for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
 143             tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
 144                tsegall = CAN_CALC_SYNC_SEG + tseg / 2;
 145
 146                /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
 147                brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
 148
 149                /* choose brp step which is possible in system */
 150                brp = (brp / btc->brp_inc) * btc->brp_inc;
 151                if ((brp < btc->brp_min) || (brp > btc->brp_max))
 152                        continue;
 153
 154                bitrate = priv->clock.freq / (brp * tsegall);
 155                bitrate_error = abs(bt->bitrate - bitrate);
 156
 157                /* tseg brp biterror */
 158                if (bitrate_error > best_bitrate_error)
 159                        continue;
 160
 161                /* reset sample point error if we have a better bitrate */
 162                if (bitrate_error < best_bitrate_error)
 163                        best_sample_point_error = UINT_MAX;
 164
 165                can_update_sample_point(btc, sample_point_nominal, tseg / 2, &tseg1, &tseg2, &sample_point_error);
 166                if (sample_point_error > best_sample_point_error)
 167                        continue;
 168
 169                best_sample_point_error = sample_point_error;
 170                best_bitrate_error = bitrate_error;
 171                best_tseg = tseg / 2;
 172                best_brp = brp;
 173
 174                if (bitrate_error == 0 && sample_point_error == 0)
 175                        break;
 176        }
 177
 178        if (best_bitrate_error) {
 179                /* Error in one-tenth of a percent */
 180                v64 = (u64)best_bitrate_error * 1000;
 181                do_div(v64, bt->bitrate);
 182                bitrate_error = (u32)v64;
 183                if (bitrate_error > CAN_CALC_MAX_ERROR) {
 184                        netdev_err(dev,
 185                                   "bitrate error %d.%d%% too high\n",
 186                                   bitrate_error / 10, bitrate_error % 10);
 187                        return -EDOM;
 188                }
 189                netdev_warn(dev, "bitrate error %d.%d%%\n",
 190                            bitrate_error / 10, bitrate_error % 10);
 191        }
 192
 193        /* real sample point */
 194        bt->sample_point = can_update_sample_point(btc, sample_point_nominal, best_tseg,
 195                                          &tseg1, &tseg2, NULL);
 196
 197        v64 = (u64)best_brp * 1000 * 1000 * 1000;
 198        do_div(v64, priv->clock.freq);
 199        bt->tq = (u32)v64;
 200        bt->prop_seg = tseg1 / 2;
 201        bt->phase_seg1 = tseg1 - bt->prop_seg;
 202        bt->phase_seg2 = tseg2;
 203
 204        /* check for sjw user settings */
 205        if (!bt->sjw || !btc->sjw_max) {
 206                bt->sjw = 1;
 207        } else {
 208                /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
 209                if (bt->sjw > btc->sjw_max)
 210                        bt->sjw = btc->sjw_max;
 211                /* bt->sjw must not be higher than tseg2 */
 212                if (tseg2 < bt->sjw)
 213                        bt->sjw = tseg2;
 214        }
 215
 216        bt->brp = best_brp;
 217
 218        /* real bitrate */
 219        bt->bitrate = priv->clock.freq / (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2));
 220
 221        return 0;
 222}
 223#else /* !CONFIG_CAN_CALC_BITTIMING */
 224static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 225                              const struct can_bittiming_const *btc)
 226{
 227        netdev_err(dev, "bit-timing calculation not available\n");
 228        return -EINVAL;
 229}
 230#endif /* CONFIG_CAN_CALC_BITTIMING */
 231
 232/*
 233 * Checks the validity of the specified bit-timing parameters prop_seg,
 234 * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
 235 * prescaler value brp. You can find more information in the header
 236 * file linux/can/netlink.h.
 237 */
 238static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
 239                               const struct can_bittiming_const *btc)
 240{
 241        struct can_priv *priv = netdev_priv(dev);
 242        int tseg1, alltseg;
 243        u64 brp64;
 244
 245        tseg1 = bt->prop_seg + bt->phase_seg1;
 246        if (!bt->sjw)
 247                bt->sjw = 1;
 248        if (bt->sjw > btc->sjw_max ||
 249            tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
 250            bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
 251                return -ERANGE;
 252
 253        brp64 = (u64)priv->clock.freq * (u64)bt->tq;
 254        if (btc->brp_inc > 1)
 255                do_div(brp64, btc->brp_inc);
 256        brp64 += 500000000UL - 1;
 257        do_div(brp64, 1000000000UL); /* the practicable BRP */
 258        if (btc->brp_inc > 1)
 259                brp64 *= btc->brp_inc;
 260        bt->brp = (u32)brp64;
 261
 262        if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
 263                return -EINVAL;
 264
 265        alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
 266        bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
 267        bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
 268
 269        return 0;
 270}
 271
 272/* Checks the validity of predefined bitrate settings */
 273static int can_validate_bitrate(struct net_device *dev, struct can_bittiming *bt,
 274                                const u32 *bitrate_const,
 275                                const unsigned int bitrate_const_cnt)
 276{
 277        struct can_priv *priv = netdev_priv(dev);
 278        unsigned int i;
 279
 280        for (i = 0; i < bitrate_const_cnt; i++) {
 281                if (bt->bitrate == bitrate_const[i])
 282                        break;
 283        }
 284
 285        if (i >= priv->bitrate_const_cnt)
 286                return -EINVAL;
 287
 288        return 0;
 289}
 290
 291static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
 292                             const struct can_bittiming_const *btc,
 293                             const u32 *bitrate_const,
 294                             const unsigned int bitrate_const_cnt)
 295{
 296        int err;
 297
 298        /*
 299         * Depending on the given can_bittiming parameter structure the CAN
 300         * timing parameters are calculated based on the provided bitrate OR
 301         * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
 302         * provided directly which are then checked and fixed up.
 303         */
 304        if (!bt->tq && bt->bitrate && btc)
 305                err = can_calc_bittiming(dev, bt, btc);
 306        else if (bt->tq && !bt->bitrate && btc)
 307                err = can_fixup_bittiming(dev, bt, btc);
 308        else if (!bt->tq && bt->bitrate && bitrate_const)
 309                err = can_validate_bitrate(dev, bt, bitrate_const,
 310                                           bitrate_const_cnt);
 311        else
 312                err = -EINVAL;
 313
 314        return err;
 315}
 316
 317static void can_update_state_error_stats(struct net_device *dev,
 318                                         enum can_state new_state)
 319{
 320        struct can_priv *priv = netdev_priv(dev);
 321
 322        if (new_state <= priv->state)
 323                return;
 324
 325        switch (new_state) {
 326        case CAN_STATE_ERROR_WARNING:
 327                priv->can_stats.error_warning++;
 328                break;
 329        case CAN_STATE_ERROR_PASSIVE:
 330                priv->can_stats.error_passive++;
 331                break;
 332        case CAN_STATE_BUS_OFF:
 333                priv->can_stats.bus_off++;
 334                break;
 335        default:
 336                break;
 337        }
 338}
 339
 340static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
 341{
 342        switch (state) {
 343        case CAN_STATE_ERROR_ACTIVE:
 344                return CAN_ERR_CRTL_ACTIVE;
 345        case CAN_STATE_ERROR_WARNING:
 346                return CAN_ERR_CRTL_TX_WARNING;
 347        case CAN_STATE_ERROR_PASSIVE:
 348                return CAN_ERR_CRTL_TX_PASSIVE;
 349        default:
 350                return 0;
 351        }
 352}
 353
 354static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
 355{
 356        switch (state) {
 357        case CAN_STATE_ERROR_ACTIVE:
 358                return CAN_ERR_CRTL_ACTIVE;
 359        case CAN_STATE_ERROR_WARNING:
 360                return CAN_ERR_CRTL_RX_WARNING;
 361        case CAN_STATE_ERROR_PASSIVE:
 362                return CAN_ERR_CRTL_RX_PASSIVE;
 363        default:
 364                return 0;
 365        }
 366}
 367
 368void can_change_state(struct net_device *dev, struct can_frame *cf,
 369                      enum can_state tx_state, enum can_state rx_state)
 370{
 371        struct can_priv *priv = netdev_priv(dev);
 372        enum can_state new_state = max(tx_state, rx_state);
 373
 374        if (unlikely(new_state == priv->state)) {
 375                netdev_warn(dev, "%s: oops, state did not change", __func__);
 376                return;
 377        }
 378
 379        netdev_dbg(dev, "New error state: %d\n", new_state);
 380
 381        can_update_state_error_stats(dev, new_state);
 382        priv->state = new_state;
 383
 384        if (!cf)
 385                return;
 386
 387        if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
 388                cf->can_id |= CAN_ERR_BUSOFF;
 389                return;
 390        }
 391
 392        cf->can_id |= CAN_ERR_CRTL;
 393        cf->data[1] |= tx_state >= rx_state ?
 394                       can_tx_state_to_frame(dev, tx_state) : 0;
 395        cf->data[1] |= tx_state <= rx_state ?
 396                       can_rx_state_to_frame(dev, rx_state) : 0;
 397}
 398EXPORT_SYMBOL_GPL(can_change_state);
 399
 400/*
 401 * Local echo of CAN messages
 402 *
 403 * CAN network devices *should* support a local echo functionality
 404 * (see Documentation/networking/can.rst). To test the handling of CAN
 405 * interfaces that do not support the local echo both driver types are
 406 * implemented. In the case that the driver does not support the echo
 407 * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
 408 * to perform the echo as a fallback solution.
 409 */
 410static void can_flush_echo_skb(struct net_device *dev)
 411{
 412        struct can_priv *priv = netdev_priv(dev);
 413        struct net_device_stats *stats = &dev->stats;
 414        int i;
 415
 416        for (i = 0; i < priv->echo_skb_max; i++) {
 417                if (priv->echo_skb[i]) {
 418                        kfree_skb(priv->echo_skb[i]);
 419                        priv->echo_skb[i] = NULL;
 420                        stats->tx_dropped++;
 421                        stats->tx_aborted_errors++;
 422                }
 423        }
 424}
 425
 426/*
 427 * Put the skb on the stack to be looped backed locally lateron
 428 *
 429 * The function is typically called in the start_xmit function
 430 * of the device driver. The driver must protect access to
 431 * priv->echo_skb, if necessary.
 432 */
 433void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 434                      unsigned int idx)
 435{
 436        struct can_priv *priv = netdev_priv(dev);
 437
 438        BUG_ON(idx >= priv->echo_skb_max);
 439
 440        /* check flag whether this packet has to be looped back */
 441        if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
 442            (skb->protocol != htons(ETH_P_CAN) &&
 443             skb->protocol != htons(ETH_P_CANFD))) {
 444                kfree_skb(skb);
 445                return;
 446        }
 447
 448        if (!priv->echo_skb[idx]) {
 449
 450                skb = can_create_echo_skb(skb);
 451                if (!skb)
 452                        return;
 453
 454                /* make settings for echo to reduce code in irq context */
 455                skb->pkt_type = PACKET_BROADCAST;
 456                skb->ip_summed = CHECKSUM_UNNECESSARY;
 457                skb->dev = dev;
 458
 459                /* save this skb for tx interrupt echo handling */
 460                priv->echo_skb[idx] = skb;
 461        } else {
 462                /* locking problem with netif_stop_queue() ?? */
 463                netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
 464                kfree_skb(skb);
 465        }
 466}
 467EXPORT_SYMBOL_GPL(can_put_echo_skb);
 468
 469struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
 470{
 471        struct can_priv *priv = netdev_priv(dev);
 472
 473        if (idx >= priv->echo_skb_max) {
 474                netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
 475                           __func__, idx, priv->echo_skb_max);
 476                return NULL;
 477        }
 478
 479        if (priv->echo_skb[idx]) {
 480                /* Using "struct canfd_frame::len" for the frame
 481                 * length is supported on both CAN and CANFD frames.
 482                 */
 483                struct sk_buff *skb = priv->echo_skb[idx];
 484                struct canfd_frame *cf = (struct canfd_frame *)skb->data;
 485                u8 len = cf->len;
 486
 487                *len_ptr = len;
 488                priv->echo_skb[idx] = NULL;
 489
 490                return skb;
 491        }
 492
 493        return NULL;
 494}
 495
 496/*
 497 * Get the skb from the stack and loop it back locally
 498 *
 499 * The function is typically called when the TX done interrupt
 500 * is handled in the device driver. The driver must protect
 501 * access to priv->echo_skb, if necessary.
 502 */
 503unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 504{
 505        struct sk_buff *skb;
 506        u8 len;
 507
 508        skb = __can_get_echo_skb(dev, idx, &len);
 509        if (!skb)
 510                return 0;
 511
 512        netif_rx(skb);
 513
 514        return len;
 515}
 516EXPORT_SYMBOL_GPL(can_get_echo_skb);
 517
 518/*
 519  * Remove the skb from the stack and free it.
 520  *
 521  * The function is typically called when TX failed.
 522  */
 523void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 524{
 525        struct can_priv *priv = netdev_priv(dev);
 526
 527        BUG_ON(idx >= priv->echo_skb_max);
 528
 529        if (priv->echo_skb[idx]) {
 530                dev_kfree_skb_any(priv->echo_skb[idx]);
 531                priv->echo_skb[idx] = NULL;
 532        }
 533}
 534EXPORT_SYMBOL_GPL(can_free_echo_skb);
 535
 536/*
 537 * CAN device restart for bus-off recovery
 538 */
 539static void can_restart(struct net_device *dev)
 540{
 541        struct can_priv *priv = netdev_priv(dev);
 542        struct net_device_stats *stats = &dev->stats;
 543        struct sk_buff *skb;
 544        struct can_frame *cf;
 545        int err;
 546
 547        BUG_ON(netif_carrier_ok(dev));
 548
 549        /*
 550         * No synchronization needed because the device is bus-off and
 551         * no messages can come in or go out.
 552         */
 553        can_flush_echo_skb(dev);
 554
 555        /* send restart message upstream */
 556        skb = alloc_can_err_skb(dev, &cf);
 557        if (skb == NULL) {
 558                err = -ENOMEM;
 559                goto restart;
 560        }
 561        cf->can_id |= CAN_ERR_RESTARTED;
 562
 563        netif_rx(skb);
 564
 565        stats->rx_packets++;
 566        stats->rx_bytes += cf->can_dlc;
 567
 568restart:
 569        netdev_dbg(dev, "restarted\n");
 570        priv->can_stats.restarts++;
 571
 572        /* Now restart the device */
 573        err = priv->do_set_mode(dev, CAN_MODE_START);
 574
 575        netif_carrier_on(dev);
 576        if (err)
 577                netdev_err(dev, "Error %d during restart", err);
 578}
 579
 580static void can_restart_work(struct work_struct *work)
 581{
 582        struct delayed_work *dwork = to_delayed_work(work);
 583        struct can_priv *priv = container_of(dwork, struct can_priv, restart_work);
 584
 585        can_restart(priv->dev);
 586}
 587
 588int can_restart_now(struct net_device *dev)
 589{
 590        struct can_priv *priv = netdev_priv(dev);
 591
 592        /*
 593         * A manual restart is only permitted if automatic restart is
 594         * disabled and the device is in the bus-off state
 595         */
 596        if (priv->restart_ms)
 597                return -EINVAL;
 598        if (priv->state != CAN_STATE_BUS_OFF)
 599                return -EBUSY;
 600
 601        cancel_delayed_work_sync(&priv->restart_work);
 602        can_restart(dev);
 603
 604        return 0;
 605}
 606
 607/*
 608 * CAN bus-off
 609 *
 610 * This functions should be called when the device goes bus-off to
 611 * tell the netif layer that no more packets can be sent or received.
 612 * If enabled, a timer is started to trigger bus-off recovery.
 613 */
 614void can_bus_off(struct net_device *dev)
 615{
 616        struct can_priv *priv = netdev_priv(dev);
 617
 618        netdev_info(dev, "bus-off\n");
 619
 620        netif_carrier_off(dev);
 621
 622        if (priv->restart_ms)
 623                schedule_delayed_work(&priv->restart_work,
 624                                      msecs_to_jiffies(priv->restart_ms));
 625}
 626EXPORT_SYMBOL_GPL(can_bus_off);
 627
 628static void can_setup(struct net_device *dev)
 629{
 630        dev->type = ARPHRD_CAN;
 631        dev->mtu = CAN_MTU;
 632        dev->hard_header_len = 0;
 633        dev->addr_len = 0;
 634        dev->tx_queue_len = 10;
 635
 636        /* New-style flags. */
 637        dev->flags = IFF_NOARP;
 638        dev->features = NETIF_F_HW_CSUM;
 639}
 640
 641struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 642{
 643        struct sk_buff *skb;
 644
 645        skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 646                               sizeof(struct can_frame));
 647        if (unlikely(!skb))
 648                return NULL;
 649
 650        skb->protocol = htons(ETH_P_CAN);
 651        skb->pkt_type = PACKET_BROADCAST;
 652        skb->ip_summed = CHECKSUM_UNNECESSARY;
 653
 654        skb_reset_mac_header(skb);
 655        skb_reset_network_header(skb);
 656        skb_reset_transport_header(skb);
 657
 658        can_skb_reserve(skb);
 659        can_skb_prv(skb)->ifindex = dev->ifindex;
 660        can_skb_prv(skb)->skbcnt = 0;
 661
 662        *cf = skb_put_zero(skb, sizeof(struct can_frame));
 663
 664        return skb;
 665}
 666EXPORT_SYMBOL_GPL(alloc_can_skb);
 667
 668struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 669                                struct canfd_frame **cfd)
 670{
 671        struct sk_buff *skb;
 672
 673        skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 674                               sizeof(struct canfd_frame));
 675        if (unlikely(!skb))
 676                return NULL;
 677
 678        skb->protocol = htons(ETH_P_CANFD);
 679        skb->pkt_type = PACKET_BROADCAST;
 680        skb->ip_summed = CHECKSUM_UNNECESSARY;
 681
 682        skb_reset_mac_header(skb);
 683        skb_reset_network_header(skb);
 684        skb_reset_transport_header(skb);
 685
 686        can_skb_reserve(skb);
 687        can_skb_prv(skb)->ifindex = dev->ifindex;
 688        can_skb_prv(skb)->skbcnt = 0;
 689
 690        *cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
 691
 692        return skb;
 693}
 694EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 695
 696struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 697{
 698        struct sk_buff *skb;
 699
 700        skb = alloc_can_skb(dev, cf);
 701        if (unlikely(!skb))
 702                return NULL;
 703
 704        (*cf)->can_id = CAN_ERR_FLAG;
 705        (*cf)->can_dlc = CAN_ERR_DLC;
 706
 707        return skb;
 708}
 709EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 710
 711/*
 712 * Allocate and setup space for the CAN network device
 713 */
 714struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
 715                                    unsigned int txqs, unsigned int rxqs)
 716{
 717        struct net_device *dev;
 718        struct can_priv *priv;
 719        int size;
 720
 721        if (echo_skb_max)
 722                size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
 723                        echo_skb_max * sizeof(struct sk_buff *);
 724        else
 725                size = sizeof_priv;
 726
 727        dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup,
 728                               txqs, rxqs);
 729        if (!dev)
 730                return NULL;
 731
 732        priv = netdev_priv(dev);
 733        priv->dev = dev;
 734
 735        if (echo_skb_max) {
 736                priv->echo_skb_max = echo_skb_max;
 737                priv->echo_skb = (void *)priv +
 738                        ALIGN(sizeof_priv, sizeof(struct sk_buff *));
 739        }
 740
 741        priv->state = CAN_STATE_STOPPED;
 742
 743        INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
 744
 745        return dev;
 746}
 747EXPORT_SYMBOL_GPL(alloc_candev_mqs);
 748
 749/*
 750 * Free space of the CAN network device
 751 */
 752void free_candev(struct net_device *dev)
 753{
 754        free_netdev(dev);
 755}
 756EXPORT_SYMBOL_GPL(free_candev);
 757
 758/*
 759 * changing MTU and control mode for CAN/CANFD devices
 760 */
 761int can_change_mtu(struct net_device *dev, int new_mtu)
 762{
 763        struct can_priv *priv = netdev_priv(dev);
 764
 765        /* Do not allow changing the MTU while running */
 766        if (dev->flags & IFF_UP)
 767                return -EBUSY;
 768
 769        /* allow change of MTU according to the CANFD ability of the device */
 770        switch (new_mtu) {
 771        case CAN_MTU:
 772                /* 'CANFD-only' controllers can not switch to CAN_MTU */
 773                if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 774                        return -EINVAL;
 775
 776                priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 777                break;
 778
 779        case CANFD_MTU:
 780                /* check for potential CANFD ability */
 781                if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 782                    !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 783                        return -EINVAL;
 784
 785                priv->ctrlmode |= CAN_CTRLMODE_FD;
 786                break;
 787
 788        default:
 789                return -EINVAL;
 790        }
 791
 792        dev->mtu = new_mtu;
 793        return 0;
 794}
 795EXPORT_SYMBOL_GPL(can_change_mtu);
 796
 797/*
 798 * Common open function when the device gets opened.
 799 *
 800 * This function should be called in the open function of the device
 801 * driver.
 802 */
 803int open_candev(struct net_device *dev)
 804{
 805        struct can_priv *priv = netdev_priv(dev);
 806
 807        if (!priv->bittiming.bitrate) {
 808                netdev_err(dev, "bit-timing not yet defined\n");
 809                return -EINVAL;
 810        }
 811
 812        /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 813        if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 814            (!priv->data_bittiming.bitrate ||
 815             (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
 816                netdev_err(dev, "incorrect/missing data bit-timing\n");
 817                return -EINVAL;
 818        }
 819
 820        /* Switch carrier on if device was stopped while in bus-off state */
 821        if (!netif_carrier_ok(dev))
 822                netif_carrier_on(dev);
 823
 824        return 0;
 825}
 826EXPORT_SYMBOL_GPL(open_candev);
 827
 828#ifdef CONFIG_OF
 829/* Common function that can be used to understand the limitation of
 830 * a transceiver when it provides no means to determine these limitations
 831 * at runtime.
 832 */
 833void of_can_transceiver(struct net_device *dev)
 834{
 835        struct device_node *dn;
 836        struct can_priv *priv = netdev_priv(dev);
 837        struct device_node *np = dev->dev.parent->of_node;
 838        int ret;
 839
 840        dn = of_get_child_by_name(np, "can-transceiver");
 841        if (!dn)
 842                return;
 843
 844        ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max);
 845        if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
 846                netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
 847}
 848EXPORT_SYMBOL_GPL(of_can_transceiver);
 849#endif
 850
 851/*
 852 * Common close function for cleanup before the device gets closed.
 853 *
 854 * This function should be called in the close function of the device
 855 * driver.
 856 */
 857void close_candev(struct net_device *dev)
 858{
 859        struct can_priv *priv = netdev_priv(dev);
 860
 861        cancel_delayed_work_sync(&priv->restart_work);
 862        can_flush_echo_skb(dev);
 863}
 864EXPORT_SYMBOL_GPL(close_candev);
 865
 866/*
 867 * CAN netlink interface
 868 */
 869static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 870        [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 871        [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 872        [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 873        [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 874        [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 875        [IFLA_CAN_BITTIMING_CONST]
 876                                = { .len = sizeof(struct can_bittiming_const) },
 877        [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 878        [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 879        [IFLA_CAN_DATA_BITTIMING]
 880                                = { .len = sizeof(struct can_bittiming) },
 881        [IFLA_CAN_DATA_BITTIMING_CONST]
 882                                = { .len = sizeof(struct can_bittiming_const) },
 883};
 884
 885static int can_validate(struct nlattr *tb[], struct nlattr *data[],
 886                        struct netlink_ext_ack *extack)
 887{
 888        bool is_can_fd = false;
 889
 890        /* Make sure that valid CAN FD configurations always consist of
 891         * - nominal/arbitration bittiming
 892         * - data bittiming
 893         * - control mode with CAN_CTRLMODE_FD set
 894         */
 895
 896        if (!data)
 897                return 0;
 898
 899        if (data[IFLA_CAN_CTRLMODE]) {
 900                struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 901
 902                is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 903        }
 904
 905        if (is_can_fd) {
 906                if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 907                        return -EOPNOTSUPP;
 908        }
 909
 910        if (data[IFLA_CAN_DATA_BITTIMING]) {
 911                if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 912                        return -EOPNOTSUPP;
 913        }
 914
 915        return 0;
 916}
 917
 918static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 919                          struct nlattr *data[],
 920                          struct netlink_ext_ack *extack)
 921{
 922        struct can_priv *priv = netdev_priv(dev);
 923        int err;
 924
 925        /* We need synchronization with dev->stop() */
 926        ASSERT_RTNL();
 927
 928        if (data[IFLA_CAN_BITTIMING]) {
 929                struct can_bittiming bt;
 930
 931                /* Do not allow changing bittiming while running */
 932                if (dev->flags & IFF_UP)
 933                        return -EBUSY;
 934
 935                /* Calculate bittiming parameters based on
 936                 * bittiming_const if set, otherwise pass bitrate
 937                 * directly via do_set_bitrate(). Bail out if neither
 938                 * is given.
 939                 */
 940                if (!priv->bittiming_const && !priv->do_set_bittiming)
 941                        return -EOPNOTSUPP;
 942
 943                memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 944                err = can_get_bittiming(dev, &bt,
 945                                        priv->bittiming_const,
 946                                        priv->bitrate_const,
 947                                        priv->bitrate_const_cnt);
 948                if (err)
 949                        return err;
 950
 951                if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) {
 952                        netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n",
 953                                   priv->bitrate_max);
 954                        return -EINVAL;
 955                }
 956
 957                memcpy(&priv->bittiming, &bt, sizeof(bt));
 958
 959                if (priv->do_set_bittiming) {
 960                        /* Finally, set the bit-timing registers */
 961                        err = priv->do_set_bittiming(dev);
 962                        if (err)
 963                                return err;
 964                }
 965        }
 966
 967        if (data[IFLA_CAN_CTRLMODE]) {
 968                struct can_ctrlmode *cm;
 969                u32 ctrlstatic;
 970                u32 maskedflags;
 971
 972                /* Do not allow changing controller mode while running */
 973                if (dev->flags & IFF_UP)
 974                        return -EBUSY;
 975                cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 976                ctrlstatic = priv->ctrlmode_static;
 977                maskedflags = cm->flags & cm->mask;
 978
 979                /* check whether provided bits are allowed to be passed */
 980                if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
 981                        return -EOPNOTSUPP;
 982
 983                /* do not check for static fd-non-iso if 'fd' is disabled */
 984                if (!(maskedflags & CAN_CTRLMODE_FD))
 985                        ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
 986
 987                /* make sure static options are provided by configuration */
 988                if ((maskedflags & ctrlstatic) != ctrlstatic)
 989                        return -EOPNOTSUPP;
 990
 991                /* clear bits to be modified and copy the flag values */
 992                priv->ctrlmode &= ~cm->mask;
 993                priv->ctrlmode |= maskedflags;
 994
 995                /* CAN_CTRLMODE_FD can only be set when driver supports FD */
 996                if (priv->ctrlmode & CAN_CTRLMODE_FD)
 997                        dev->mtu = CANFD_MTU;
 998                else
 999                        dev->mtu = CAN_MTU;
1000        }
1001
1002        if (data[IFLA_CAN_RESTART_MS]) {
1003                /* Do not allow changing restart delay while running */
1004                if (dev->flags & IFF_UP)
1005                        return -EBUSY;
1006                priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
1007        }
1008
1009        if (data[IFLA_CAN_RESTART]) {
1010                /* Do not allow a restart while not running */
1011                if (!(dev->flags & IFF_UP))
1012                        return -EINVAL;
1013                err = can_restart_now(dev);
1014                if (err)
1015                        return err;
1016        }
1017
1018        if (data[IFLA_CAN_DATA_BITTIMING]) {
1019                struct can_bittiming dbt;
1020
1021                /* Do not allow changing bittiming while running */
1022                if (dev->flags & IFF_UP)
1023                        return -EBUSY;
1024
1025                /* Calculate bittiming parameters based on
1026                 * data_bittiming_const if set, otherwise pass bitrate
1027                 * directly via do_set_bitrate(). Bail out if neither
1028                 * is given.
1029                 */
1030                if (!priv->data_bittiming_const && !priv->do_set_data_bittiming)
1031                        return -EOPNOTSUPP;
1032
1033                memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
1034                       sizeof(dbt));
1035                err = can_get_bittiming(dev, &dbt,
1036                                        priv->data_bittiming_const,
1037                                        priv->data_bitrate_const,
1038                                        priv->data_bitrate_const_cnt);
1039                if (err)
1040                        return err;
1041
1042                if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
1043                        netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
1044                                   priv->bitrate_max);
1045                        return -EINVAL;
1046                }
1047
1048                memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
1049
1050                if (priv->do_set_data_bittiming) {
1051                        /* Finally, set the bit-timing registers */
1052                        err = priv->do_set_data_bittiming(dev);
1053                        if (err)
1054                                return err;
1055                }
1056        }
1057
1058        if (data[IFLA_CAN_TERMINATION]) {
1059                const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]);
1060                const unsigned int num_term = priv->termination_const_cnt;
1061                unsigned int i;
1062
1063                if (!priv->do_set_termination)
1064                        return -EOPNOTSUPP;
1065
1066                /* check whether given value is supported by the interface */
1067                for (i = 0; i < num_term; i++) {
1068                        if (termval == priv->termination_const[i])
1069                                break;
1070                }
1071                if (i >= num_term)
1072                        return -EINVAL;
1073
1074                /* Finally, set the termination value */
1075                err = priv->do_set_termination(dev, termval);
1076                if (err)
1077                        return err;
1078
1079                priv->termination = termval;
1080        }
1081
1082        return 0;
1083}
1084
1085static size_t can_get_size(const struct net_device *dev)
1086{
1087        struct can_priv *priv = netdev_priv(dev);
1088        size_t size = 0;
1089
1090        if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
1091                size += nla_total_size(sizeof(struct can_bittiming));
1092        if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
1093                size += nla_total_size(sizeof(struct can_bittiming_const));
1094        size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
1095        size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
1096        size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
1097        size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
1098        if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
1099                size += nla_total_size(sizeof(struct can_berr_counter));
1100        if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
1101                size += nla_total_size(sizeof(struct can_bittiming));
1102        if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
1103                size += nla_total_size(sizeof(struct can_bittiming_const));
1104        if (priv->termination_const) {
1105                size += nla_total_size(sizeof(priv->termination));              /* IFLA_CAN_TERMINATION */
1106                size += nla_total_size(sizeof(*priv->termination_const) *       /* IFLA_CAN_TERMINATION_CONST */
1107                                       priv->termination_const_cnt);
1108        }
1109        if (priv->bitrate_const)                                /* IFLA_CAN_BITRATE_CONST */
1110                size += nla_total_size(sizeof(*priv->bitrate_const) *
1111                                       priv->bitrate_const_cnt);
1112        if (priv->data_bitrate_const)                           /* IFLA_CAN_DATA_BITRATE_CONST */
1113                size += nla_total_size(sizeof(*priv->data_bitrate_const) *
1114                                       priv->data_bitrate_const_cnt);
1115        size += sizeof(priv->bitrate_max);                      /* IFLA_CAN_BITRATE_MAX */
1116
1117        return size;
1118}
1119
1120static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
1121{
1122        struct can_priv *priv = netdev_priv(dev);
1123        struct can_ctrlmode cm = {.flags = priv->ctrlmode};
1124        struct can_berr_counter bec;
1125        enum can_state state = priv->state;
1126
1127        if (priv->do_get_state)
1128                priv->do_get_state(dev, &state);
1129
1130        if ((priv->bittiming.bitrate &&
1131             nla_put(skb, IFLA_CAN_BITTIMING,
1132                     sizeof(priv->bittiming), &priv->bittiming)) ||
1133
1134            (priv->bittiming_const &&
1135             nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1136                     sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1137
1138            nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1139            nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1140            nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1141            nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1142
1143            (priv->do_get_berr_counter &&
1144             !priv->do_get_berr_counter(dev, &bec) &&
1145             nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1146
1147            (priv->data_bittiming.bitrate &&
1148             nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1149                     sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1150
1151            (priv->data_bittiming_const &&
1152             nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1153                     sizeof(*priv->data_bittiming_const),
1154                     priv->data_bittiming_const)) ||
1155
1156            (priv->termination_const &&
1157             (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||
1158              nla_put(skb, IFLA_CAN_TERMINATION_CONST,
1159                      sizeof(*priv->termination_const) *
1160                      priv->termination_const_cnt,
1161                      priv->termination_const))) ||
1162
1163            (priv->bitrate_const &&
1164             nla_put(skb, IFLA_CAN_BITRATE_CONST,
1165                     sizeof(*priv->bitrate_const) *
1166                     priv->bitrate_const_cnt,
1167                     priv->bitrate_const)) ||
1168
1169            (priv->data_bitrate_const &&
1170             nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
1171                     sizeof(*priv->data_bitrate_const) *
1172                     priv->data_bitrate_const_cnt,
1173                     priv->data_bitrate_const)) ||
1174
1175            (nla_put(skb, IFLA_CAN_BITRATE_MAX,
1176                     sizeof(priv->bitrate_max),
1177                     &priv->bitrate_max))
1178            )
1179
1180                return -EMSGSIZE;
1181
1182        return 0;
1183}
1184
1185static size_t can_get_xstats_size(const struct net_device *dev)
1186{
1187        return sizeof(struct can_device_stats);
1188}
1189
1190static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1191{
1192        struct can_priv *priv = netdev_priv(dev);
1193
1194        if (nla_put(skb, IFLA_INFO_XSTATS,
1195                    sizeof(priv->can_stats), &priv->can_stats))
1196                goto nla_put_failure;
1197        return 0;
1198
1199nla_put_failure:
1200        return -EMSGSIZE;
1201}
1202
1203static int can_newlink(struct net *src_net, struct net_device *dev,
1204                       struct nlattr *tb[], struct nlattr *data[],
1205                       struct netlink_ext_ack *extack)
1206{
1207        return -EOPNOTSUPP;
1208}
1209
1210static void can_dellink(struct net_device *dev, struct list_head *head)
1211{
1212        return;
1213}
1214
1215static struct rtnl_link_ops can_link_ops __read_mostly = {
1216        .kind           = "can",
1217        .maxtype        = IFLA_CAN_MAX,
1218        .policy         = can_policy,
1219        .setup          = can_setup,
1220        .validate       = can_validate,
1221        .newlink        = can_newlink,
1222        .changelink     = can_changelink,
1223        .dellink        = can_dellink,
1224        .get_size       = can_get_size,
1225        .fill_info      = can_fill_info,
1226        .get_xstats_size = can_get_xstats_size,
1227        .fill_xstats    = can_fill_xstats,
1228};
1229
1230/*
1231 * Register the CAN network device
1232 */
1233int register_candev(struct net_device *dev)
1234{
1235        struct can_priv *priv = netdev_priv(dev);
1236
1237        /* Ensure termination_const, termination_const_cnt and
1238         * do_set_termination consistency. All must be either set or
1239         * unset.
1240         */
1241        if ((!priv->termination_const != !priv->termination_const_cnt) ||
1242            (!priv->termination_const != !priv->do_set_termination))
1243                return -EINVAL;
1244
1245        if (!priv->bitrate_const != !priv->bitrate_const_cnt)
1246                return -EINVAL;
1247
1248        if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
1249                return -EINVAL;
1250
1251        dev->rtnl_link_ops = &can_link_ops;
1252        return register_netdev(dev);
1253}
1254EXPORT_SYMBOL_GPL(register_candev);
1255
1256/*
1257 * Unregister the CAN network device
1258 */
1259void unregister_candev(struct net_device *dev)
1260{
1261        unregister_netdev(dev);
1262}
1263EXPORT_SYMBOL_GPL(unregister_candev);
1264
1265/*
1266 * Test if a network device is a candev based device
1267 * and return the can_priv* if so.
1268 */
1269struct can_priv *safe_candev_priv(struct net_device *dev)
1270{
1271        if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1272                return NULL;
1273
1274        return netdev_priv(dev);
1275}
1276EXPORT_SYMBOL_GPL(safe_candev_priv);
1277
1278static __init int can_dev_init(void)
1279{
1280        int err;
1281
1282        can_led_notifier_init();
1283
1284        err = rtnl_link_register(&can_link_ops);
1285        if (!err)
1286                printk(KERN_INFO MOD_DESC "\n");
1287
1288        return err;
1289}
1290module_init(can_dev_init);
1291
1292static __exit void can_dev_exit(void)
1293{
1294        rtnl_link_unregister(&can_link_ops);
1295
1296        can_led_notifier_exit();
1297}
1298module_exit(can_dev_exit);
1299
1300MODULE_ALIAS_RTNL_LINK("can");
1301