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/can.h>
  25 #include <linux/can/dev.h>
  26 #include <linux/can/skb.h>
  27 #include <linux/can/netlink.h>
  28 #include <linux/can/led.h>
  29 #include <net/rtnetlink.h>
  30
  31 #define MOD_DESC "CAN device driver interface"
  32
  33 MODULE_DESCRIPTION(MOD_DESC);
  34 MODULE_LICENSE("GPL v2");
  35 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
  36
  37 /* CAN DLC to real data length conversion helpers */
  38
  39 static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
  40                              8, 12, 16, 20, 24, 32, 48, 64};
  41
  42 /* get data length from can_dlc with sanitized can_dlc */
  43 u8 can_dlc2len(u8 can_dlc)
  44 {
  45         return dlc2len[can_dlc & 0x0F];
  46 }
  47 EXPORT_SYMBOL_GPL(can_dlc2len);
  48
  49 static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,         /* 0 - 8 */
  50                              9, 9, 9, 9,                        /* 9 - 12 */
  51                              10, 10, 10, 10,                    /* 13 - 16 */
  52                              11, 11, 11, 11,                    /* 17 - 20 */
  53                              12, 12, 12, 12,                    /* 21 - 24 */
  54                              13, 13, 13, 13, 13, 13, 13, 13,    /* 25 - 32 */
  55                              14, 14, 14, 14, 14, 14, 14, 14,    /* 33 - 40 */
  56                              14, 14, 14, 14, 14, 14, 14, 14,    /* 41 - 48 */
  57                              15, 15, 15, 15, 15, 15, 15, 15,    /* 49 - 56 */
  58                              15, 15, 15, 15, 15, 15, 15, 15};   /* 57 - 64 */
  59
  60 /* map the sanitized data length to an appropriate data length code */
  61 u8 can_len2dlc(u8 len)
  62 {
  63         if (unlikely(len > 64))
  64                 return 0xF;
  65
  66         return len2dlc[len];
  67 }
  68 EXPORT_SYMBOL_GPL(can_len2dlc);
  69
  70 #ifdef CONFIG_CAN_CALC_BITTIMING
  71 #define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
  72
  73 /*
  74  * Bit-timing calculation derived from:
  75  *
  76  * Code based on LinCAN sources and H8S2638 project
  77  * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
  78  * Copyright 2005      Stanislav Marek
  79  * email: pisa@cmp.felk.cvut.cz
  80  *
  81  * Calculates proper bit-timing parameters for a specified bit-rate
  82  * and sample-point, which can then be used to set the bit-timing
  83  * registers of the CAN controller. You can find more information
  84  * in the header file linux/can/netlink.h.
  85  */
  86 static int can_update_spt(const struct can_bittiming_const *btc,
  87                           int sampl_pt, int tseg, int *tseg1, int *tseg2)
  88 {
  89         *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
  90         if (*tseg2 < btc->tseg2_min)
  91                 *tseg2 = btc->tseg2_min;
  92         if (*tseg2 > btc->tseg2_max)
  93                 *tseg2 = btc->tseg2_max;
  94         *tseg1 = tseg - *tseg2;
  95         if (*tseg1 > btc->tseg1_max) {
  96                 *tseg1 = btc->tseg1_max;
  97                 *tseg2 = tseg - *tseg1;
  98         }
  99         return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
 100 }
 101
 102 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 103                               const struct can_bittiming_const *btc)
 104 {
 105         struct can_priv *priv = netdev_priv(dev);
 106         long best_error = 1000000000, error = 0;
 107         int best_tseg = 0, best_brp = 0, brp = 0;
 108         int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
 109         int spt_error = 1000, spt = 0, sampl_pt;
 110         long rate;
 111         u64 v64;
 112
 113         /* Use CiA recommended sample points */
 114         if (bt->sample_point) {
 115                 sampl_pt = bt->sample_point;
 116         } else {
 117                 if (bt->bitrate > 800000)
 118                         sampl_pt = 750;
 119                 else if (bt->bitrate > 500000)
 120                         sampl_pt = 800;
 121                 else
 122                         sampl_pt = 875;
 123         }
 124
 125         /* tseg even = round down, odd = round up */
 126         for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
 127              tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
 128                 tsegall = 1 + tseg / 2;
 129                 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
 130                 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
 131                 /* chose brp step which is possible in system */
 132                 brp = (brp / btc->brp_inc) * btc->brp_inc;
 133                 if ((brp < btc->brp_min) || (brp > btc->brp_max))
 134                         continue;
 135                 rate = priv->clock.freq / (brp * tsegall);
 136                 error = bt->bitrate - rate;
 137                 /* tseg brp biterror */
 138                 if (error < 0)
 139                         error = -error;
 140                 if (error > best_error)
 141                         continue;
 142                 best_error = error;
 143                 if (error == 0) {
 144                         spt = can_update_spt(btc, sampl_pt, tseg / 2,
 145                                              &tseg1, &tseg2);
 146                         error = sampl_pt - spt;
 147                         if (error < 0)
 148                                 error = -error;
 149                         if (error > spt_error)
 150                                 continue;
 151                         spt_error = error;
 152                 }
 153                 best_tseg = tseg / 2;
 154                 best_brp = brp;
 155                 if (error == 0)
 156                         break;
 157         }
 158
 159         if (best_error) {
 160                 /* Error in one-tenth of a percent */
 161                 error = (best_error * 1000) / bt->bitrate;
 162                 if (error > CAN_CALC_MAX_ERROR) {
 163                         netdev_err(dev,
 164                                    "bitrate error %ld.%ld%% too high\n",
 165                                    error / 10, error % 10);
 166                         return -EDOM;
 167                 } else {
 168                         netdev_warn(dev, "bitrate error %ld.%ld%%\n",
 169                                     error / 10, error % 10);
 170                 }
 171         }
 172
 173         /* real sample point */
 174         bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg,
 175                                           &tseg1, &tseg2);
 176
 177         v64 = (u64)best_brp * 1000000000UL;
 178         do_div(v64, priv->clock.freq);
 179         bt->tq = (u32)v64;
 180         bt->prop_seg = tseg1 / 2;
 181         bt->phase_seg1 = tseg1 - bt->prop_seg;
 182         bt->phase_seg2 = tseg2;
 183
 184         /* check for sjw user settings */
 185         if (!bt->sjw || !btc->sjw_max)
 186                 bt->sjw = 1;
 187         else {
 188                 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
 189                 if (bt->sjw > btc->sjw_max)
 190                         bt->sjw = btc->sjw_max;
 191                 /* bt->sjw must not be higher than tseg2 */
 192                 if (tseg2 < bt->sjw)
 193                         bt->sjw = tseg2;
 194         }
 195
 196         bt->brp = best_brp;
 197         /* real bit-rate */
 198         bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));
 199
 200         return 0;
 201 }
 202 #else /* !CONFIG_CAN_CALC_BITTIMING */
 203 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 204                               const struct can_bittiming_const *btc)
 205 {
 206         netdev_err(dev, "bit-timing calculation not available\n");
 207         return -EINVAL;
 208 }
 209 #endif /* CONFIG_CAN_CALC_BITTIMING */
 210
 211 /*
 212  * Checks the validity of the specified bit-timing parameters prop_seg,
 213  * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
 214  * prescaler value brp. You can find more information in the header
 215  * file linux/can/netlink.h.
 216  */
 217 static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
 218                                const struct can_bittiming_const *btc)
 219 {
 220         struct can_priv *priv = netdev_priv(dev);
 221         int tseg1, alltseg;
 222         u64 brp64;
 223
 224         tseg1 = bt->prop_seg + bt->phase_seg1;
 225         if (!bt->sjw)
 226                 bt->sjw = 1;
 227         if (bt->sjw > btc->sjw_max ||
 228             tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
 229             bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
 230                 return -ERANGE;
 231
 232         brp64 = (u64)priv->clock.freq * (u64)bt->tq;
 233         if (btc->brp_inc > 1)
 234                 do_div(brp64, btc->brp_inc);
 235         brp64 += 500000000UL - 1;
 236         do_div(brp64, 1000000000UL); /* the practicable BRP */
 237         if (btc->brp_inc > 1)
 238                 brp64 *= btc->brp_inc;
 239         bt->brp = (u32)brp64;
 240
 241         if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
 242                 return -EINVAL;
 243
 244         alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
 245         bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
 246         bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
 247
 248         return 0;
 249 }
 250
 251 static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
 252                              const struct can_bittiming_const *btc)
 253 {
 254         int err;
 255
 256         /* Check if the CAN device has bit-timing parameters */
 257         if (!btc)
 258                 return -EOPNOTSUPP;
 259
 260         /*
 261          * Depending on the given can_bittiming parameter structure the CAN
 262          * timing parameters are calculated based on the provided bitrate OR
 263          * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
 264          * provided directly which are then checked and fixed up.
 265          */
 266         if (!bt->tq && bt->bitrate)
 267                 err = can_calc_bittiming(dev, bt, btc);
 268         else if (bt->tq && !bt->bitrate)
 269                 err = can_fixup_bittiming(dev, bt, btc);
 270         else
 271                 err = -EINVAL;
 272
 273         return err;
 274 }
 275
 276 static void can_update_state_error_stats(struct net_device *dev,
 277                                          enum can_state new_state)
 278 {
 279         struct can_priv *priv = netdev_priv(dev);
 280
 281         if (new_state <= priv->state)
 282                 return;
 283
 284         switch (new_state) {
 285         case CAN_STATE_ERROR_WARNING:
 286                 priv->can_stats.error_warning++;
 287                 break;
 288         case CAN_STATE_ERROR_PASSIVE:
 289                 priv->can_stats.error_passive++;
 290                 break;
 291         case CAN_STATE_BUS_OFF:
 292         default:
 293                 break;
 294         };
 295 }
 296
 297 static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
 298 {
 299         switch (state) {
 300         case CAN_STATE_ERROR_ACTIVE:
 301                 return CAN_ERR_CRTL_ACTIVE;
 302         case CAN_STATE_ERROR_WARNING:
 303                 return CAN_ERR_CRTL_TX_WARNING;
 304         case CAN_STATE_ERROR_PASSIVE:
 305                 return CAN_ERR_CRTL_TX_PASSIVE;
 306         default:
 307                 return 0;
 308         }
 309 }
 310
 311 static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
 312 {
 313         switch (state) {
 314         case CAN_STATE_ERROR_ACTIVE:
 315                 return CAN_ERR_CRTL_ACTIVE;
 316         case CAN_STATE_ERROR_WARNING:
 317                 return CAN_ERR_CRTL_RX_WARNING;
 318         case CAN_STATE_ERROR_PASSIVE:
 319                 return CAN_ERR_CRTL_RX_PASSIVE;
 320         default:
 321                 return 0;
 322         }
 323 }
 324
 325 void can_change_state(struct net_device *dev, struct can_frame *cf,
 326                       enum can_state tx_state, enum can_state rx_state)
 327 {
 328         struct can_priv *priv = netdev_priv(dev);
 329         enum can_state new_state = max(tx_state, rx_state);
 330
 331         if (unlikely(new_state == priv->state)) {
 332                 netdev_warn(dev, "%s: oops, state did not change", __func__);
 333                 return;
 334         }
 335
 336         netdev_dbg(dev, "New error state: %d\n", new_state);
 337
 338         can_update_state_error_stats(dev, new_state);
 339         priv->state = new_state;
 340
 341         if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
 342                 cf->can_id |= CAN_ERR_BUSOFF;
 343                 return;
 344         }
 345
 346         cf->can_id |= CAN_ERR_CRTL;
 347         cf->data[1] |= tx_state >= rx_state ?
 348                        can_tx_state_to_frame(dev, tx_state) : 0;
 349         cf->data[1] |= tx_state <= rx_state ?
 350                        can_rx_state_to_frame(dev, rx_state) : 0;
 351 }
 352 EXPORT_SYMBOL_GPL(can_change_state);
 353
 354 /*
 355  * Local echo of CAN messages
 356  *
 357  * CAN network devices *should* support a local echo functionality
 358  * (see Documentation/networking/can.txt). To test the handling of CAN
 359  * interfaces that do not support the local echo both driver types are
 360  * implemented. In the case that the driver does not support the echo
 361  * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
 362  * to perform the echo as a fallback solution.
 363  */
 364 static void can_flush_echo_skb(struct net_device *dev)
 365 {
 366         struct can_priv *priv = netdev_priv(dev);
 367         struct net_device_stats *stats = &dev->stats;
 368         int i;
 369
 370         for (i = 0; i < priv->echo_skb_max; i++) {
 371                 if (priv->echo_skb[i]) {
 372                         kfree_skb(priv->echo_skb[i]);
 373                         priv->echo_skb[i] = NULL;
 374                         stats->tx_dropped++;
 375                         stats->tx_aborted_errors++;
 376                 }
 377         }
 378 }
 379
 380 /*
 381  * Put the skb on the stack to be looped backed locally lateron
 382  *
 383  * The function is typically called in the start_xmit function
 384  * of the device driver. The driver must protect access to
 385  * priv->echo_skb, if necessary.
 386  */
 387 void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 388                       unsigned int idx)
 389 {
 390         struct can_priv *priv = netdev_priv(dev);
 391
 392         BUG_ON(idx >= priv->echo_skb_max);
 393
 394         /* check flag whether this packet has to be looped back */
 395         if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
 396             (skb->protocol != htons(ETH_P_CAN) &&
 397              skb->protocol != htons(ETH_P_CANFD))) {
 398                 kfree_skb(skb);
 399                 return;
 400         }
 401
 402         if (!priv->echo_skb[idx]) {
 403
 404                 skb = can_create_echo_skb(skb);
 405                 if (!skb)
 406                         return;
 407
 408                 /* make settings for echo to reduce code in irq context */
 409                 skb->pkt_type = PACKET_BROADCAST;
 410                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 411                 skb->dev = dev;
 412
 413                 /* save this skb for tx interrupt echo handling */
 414                 priv->echo_skb[idx] = skb;
 415         } else {
 416                 /* locking problem with netif_stop_queue() ?? */
 417                 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
 418                 kfree_skb(skb);
 419         }
 420 }
 421 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 422
 423 /*
 424  * Get the skb from the stack and loop it back locally
 425  *
 426  * The function is typically called when the TX done interrupt
 427  * is handled in the device driver. The driver must protect
 428  * access to priv->echo_skb, if necessary.
 429  */
 430 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 431 {
 432         struct can_priv *priv = netdev_priv(dev);
 433
 434         BUG_ON(idx >= priv->echo_skb_max);
 435
 436         if (priv->echo_skb[idx]) {
 437                 struct sk_buff *skb = priv->echo_skb[idx];
 438                 struct can_frame *cf = (struct can_frame *)skb->data;
 439                 u8 dlc = cf->can_dlc;
 440
 441                 netif_rx(priv->echo_skb[idx]);
 442                 priv->echo_skb[idx] = NULL;
 443
 444                 return dlc;
 445         }
 446
 447         return 0;
 448 }
 449 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 450
 451 /*
 452   * Remove the skb from the stack and free it.
 453   *
 454   * The function is typically called when TX failed.
 455   */
 456 void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 457 {
 458         struct can_priv *priv = netdev_priv(dev);
 459
 460         BUG_ON(idx >= priv->echo_skb_max);
 461
 462         if (priv->echo_skb[idx]) {
 463                 dev_kfree_skb_any(priv->echo_skb[idx]);
 464                 priv->echo_skb[idx] = NULL;
 465         }
 466 }
 467 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 468
 469 /*
 470  * CAN device restart for bus-off recovery
 471  */
 472 static void can_restart(unsigned long data)
 473 {
 474         struct net_device *dev = (struct net_device *)data;
 475         struct can_priv *priv = netdev_priv(dev);
 476         struct net_device_stats *stats = &dev->stats;
 477         struct sk_buff *skb;
 478         struct can_frame *cf;
 479         int err;
 480
 481         BUG_ON(netif_carrier_ok(dev));
 482
 483         /*
 484          * No synchronization needed because the device is bus-off and
 485          * no messages can come in or go out.
 486          */
 487         can_flush_echo_skb(dev);
 488
 489         /* send restart message upstream */
 490         skb = alloc_can_err_skb(dev, &cf);
 491         if (skb == NULL) {
 492                 err = -ENOMEM;
 493                 goto restart;
 494         }
 495         cf->can_id |= CAN_ERR_RESTARTED;
 496
 497         netif_rx(skb);
 498
 499         stats->rx_packets++;
 500         stats->rx_bytes += cf->can_dlc;
 501
 502 restart:
 503         netdev_dbg(dev, "restarted\n");
 504         priv->can_stats.restarts++;
 505
 506         /* Now restart the device */
 507         err = priv->do_set_mode(dev, CAN_MODE_START);
 508
 509         netif_carrier_on(dev);
 510         if (err)
 511                 netdev_err(dev, "Error %d during restart", err);
 512 }
 513
 514 int can_restart_now(struct net_device *dev)
 515 {
 516         struct can_priv *priv = netdev_priv(dev);
 517
 518         /*
 519          * A manual restart is only permitted if automatic restart is
 520          * disabled and the device is in the bus-off state
 521          */
 522         if (priv->restart_ms)
 523                 return -EINVAL;
 524         if (priv->state != CAN_STATE_BUS_OFF)
 525                 return -EBUSY;
 526
 527         /* Runs as soon as possible in the timer context */
 528         mod_timer(&priv->restart_timer, jiffies);
 529
 530         return 0;
 531 }
 532
 533 /*
 534  * CAN bus-off
 535  *
 536  * This functions should be called when the device goes bus-off to
 537  * tell the netif layer that no more packets can be sent or received.
 538  * If enabled, a timer is started to trigger bus-off recovery.
 539  */
 540 void can_bus_off(struct net_device *dev)
 541 {
 542         struct can_priv *priv = netdev_priv(dev);
 543
 544         netdev_dbg(dev, "bus-off\n");
 545
 546         netif_carrier_off(dev);
 547         priv->can_stats.bus_off++;
 548
 549         if (priv->restart_ms)
 550                 mod_timer(&priv->restart_timer,
 551                           jiffies + (priv->restart_ms * HZ) / 1000);
 552 }
 553 EXPORT_SYMBOL_GPL(can_bus_off);
 554
 555 static void can_setup(struct net_device *dev)
 556 {
 557         dev->type = ARPHRD_CAN;
 558         dev->mtu = CAN_MTU;
 559         dev->hard_header_len = 0;
 560         dev->addr_len = 0;
 561         dev->tx_queue_len = 10;
 562
 563         /* New-style flags. */
 564         dev->flags = IFF_NOARP;
 565         dev->features = NETIF_F_HW_CSUM;
 566 }
 567
 568 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 569 {
 570         struct sk_buff *skb;
 571
 572         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 573                                sizeof(struct can_frame));
 574         if (unlikely(!skb))
 575                 return NULL;
 576
 577         skb->protocol = htons(ETH_P_CAN);
 578         skb->pkt_type = PACKET_BROADCAST;
 579         skb->ip_summed = CHECKSUM_UNNECESSARY;
 580
 581         can_skb_reserve(skb);
 582         can_skb_prv(skb)->ifindex = dev->ifindex;
 583
 584         *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
 585         memset(*cf, 0, sizeof(struct can_frame));
 586
 587         return skb;
 588 }
 589 EXPORT_SYMBOL_GPL(alloc_can_skb);
 590
 591 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 592                                 struct canfd_frame **cfd)
 593 {
 594         struct sk_buff *skb;
 595
 596         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 597                                sizeof(struct canfd_frame));
 598         if (unlikely(!skb))
 599                 return NULL;
 600
 601         skb->protocol = htons(ETH_P_CANFD);
 602         skb->pkt_type = PACKET_BROADCAST;
 603         skb->ip_summed = CHECKSUM_UNNECESSARY;
 604
 605         can_skb_reserve(skb);
 606         can_skb_prv(skb)->ifindex = dev->ifindex;
 607
 608         *cfd = (struct canfd_frame *)skb_put(skb, sizeof(struct canfd_frame));
 609         memset(*cfd, 0, sizeof(struct canfd_frame));
 610
 611         return skb;
 612 }
 613 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 614
 615 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 616 {
 617         struct sk_buff *skb;
 618
 619         skb = alloc_can_skb(dev, cf);
 620         if (unlikely(!skb))
 621                 return NULL;
 622
 623         (*cf)->can_id = CAN_ERR_FLAG;
 624         (*cf)->can_dlc = CAN_ERR_DLC;
 625
 626         return skb;
 627 }
 628 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 629
 630 /*
 631  * Allocate and setup space for the CAN network device
 632  */
 633 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
 634 {
 635         struct net_device *dev;
 636         struct can_priv *priv;
 637         int size;
 638
 639         if (echo_skb_max)
 640                 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
 641                         echo_skb_max * sizeof(struct sk_buff *);
 642         else
 643                 size = sizeof_priv;
 644
 645         dev = alloc_netdev(size, "can%d", NET_NAME_UNKNOWN, can_setup);
 646         if (!dev)
 647                 return NULL;
 648
 649         priv = netdev_priv(dev);
 650
 651         if (echo_skb_max) {
 652                 priv->echo_skb_max = echo_skb_max;
 653                 priv->echo_skb = (void *)priv +
 654                         ALIGN(sizeof_priv, sizeof(struct sk_buff *));
 655         }
 656
 657         priv->state = CAN_STATE_STOPPED;
 658
 659         init_timer(&priv->restart_timer);
 660
 661         return dev;
 662 }
 663 EXPORT_SYMBOL_GPL(alloc_candev);
 664
 665 /*
 666  * Free space of the CAN network device
 667  */
 668 void free_candev(struct net_device *dev)
 669 {
 670         free_netdev(dev);
 671 }
 672 EXPORT_SYMBOL_GPL(free_candev);
 673
 674 /*
 675  * changing MTU and control mode for CAN/CANFD devices
 676  */
 677 int can_change_mtu(struct net_device *dev, int new_mtu)
 678 {
 679         struct can_priv *priv = netdev_priv(dev);
 680
 681         /* Do not allow changing the MTU while running */
 682         if (dev->flags & IFF_UP)
 683                 return -EBUSY;
 684
 685         /* allow change of MTU according to the CANFD ability of the device */
 686         switch (new_mtu) {
 687         case CAN_MTU:
 688                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 689                 break;
 690
 691         case CANFD_MTU:
 692                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD))
 693                         return -EINVAL;
 694
 695                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 696                 break;
 697
 698         default:
 699                 return -EINVAL;
 700         }
 701
 702         dev->mtu = new_mtu;
 703         return 0;
 704 }
 705 EXPORT_SYMBOL_GPL(can_change_mtu);
 706
 707 /*
 708  * Common open function when the device gets opened.
 709  *
 710  * This function should be called in the open function of the device
 711  * driver.
 712  */
 713 int open_candev(struct net_device *dev)
 714 {
 715         struct can_priv *priv = netdev_priv(dev);
 716
 717         if (!priv->bittiming.bitrate) {
 718                 netdev_err(dev, "bit-timing not yet defined\n");
 719                 return -EINVAL;
 720         }
 721
 722         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 723         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 724             (!priv->data_bittiming.bitrate ||
 725              (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
 726                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 727                 return -EINVAL;
 728         }
 729
 730         /* Switch carrier on if device was stopped while in bus-off state */
 731         if (!netif_carrier_ok(dev))
 732                 netif_carrier_on(dev);
 733
 734         setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
 735
 736         return 0;
 737 }
 738 EXPORT_SYMBOL_GPL(open_candev);
 739
 740 /*
 741  * Common close function for cleanup before the device gets closed.
 742  *
 743  * This function should be called in the close function of the device
 744  * driver.
 745  */
 746 void close_candev(struct net_device *dev)
 747 {
 748         struct can_priv *priv = netdev_priv(dev);
 749
 750         del_timer_sync(&priv->restart_timer);
 751         can_flush_echo_skb(dev);
 752 }
 753 EXPORT_SYMBOL_GPL(close_candev);
 754
 755 /*
 756  * CAN netlink interface
 757  */
 758 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 759         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 760         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 761         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 762         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 763         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 764         [IFLA_CAN_BITTIMING_CONST]
 765                                 = { .len = sizeof(struct can_bittiming_const) },
 766         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 767         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 768         [IFLA_CAN_DATA_BITTIMING]
 769                                 = { .len = sizeof(struct can_bittiming) },
 770         [IFLA_CAN_DATA_BITTIMING_CONST]
 771                                 = { .len = sizeof(struct can_bittiming_const) },
 772 };
 773
 774 static int can_changelink(struct net_device *dev,
 775                           struct nlattr *tb[], struct nlattr *data[])
 776 {
 777         struct can_priv *priv = netdev_priv(dev);
 778         int err;
 779
 780         /* We need synchronization with dev->stop() */
 781         ASSERT_RTNL();
 782
 783         if (data[IFLA_CAN_BITTIMING]) {
 784                 struct can_bittiming bt;
 785
 786                 /* Do not allow changing bittiming while running */
 787                 if (dev->flags & IFF_UP)
 788                         return -EBUSY;
 789                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 790                 err = can_get_bittiming(dev, &bt, priv->bittiming_const);
 791                 if (err)
 792                         return err;
 793                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 794
 795                 if (priv->do_set_bittiming) {
 796                         /* Finally, set the bit-timing registers */
 797                         err = priv->do_set_bittiming(dev);
 798                         if (err)
 799                                 return err;
 800                 }
 801         }
 802
 803         if (data[IFLA_CAN_CTRLMODE]) {
 804                 struct can_ctrlmode *cm;
 805
 806                 /* Do not allow changing controller mode while running */
 807                 if (dev->flags & IFF_UP)
 808                         return -EBUSY;
 809                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 810                 if (cm->flags & ~priv->ctrlmode_supported)
 811                         return -EOPNOTSUPP;
 812                 priv->ctrlmode &= ~cm->mask;
 813                 priv->ctrlmode |= cm->flags;
 814
 815                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
 816                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
 817                         dev->mtu = CANFD_MTU;
 818                 else
 819                         dev->mtu = CAN_MTU;
 820         }
 821
 822         if (data[IFLA_CAN_RESTART_MS]) {
 823                 /* Do not allow changing restart delay while running */
 824                 if (dev->flags & IFF_UP)
 825                         return -EBUSY;
 826                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
 827         }
 828
 829         if (data[IFLA_CAN_RESTART]) {
 830                 /* Do not allow a restart while not running */
 831                 if (!(dev->flags & IFF_UP))
 832                         return -EINVAL;
 833                 err = can_restart_now(dev);
 834                 if (err)
 835                         return err;
 836         }
 837
 838         if (data[IFLA_CAN_DATA_BITTIMING]) {
 839                 struct can_bittiming dbt;
 840
 841                 /* Do not allow changing bittiming while running */
 842                 if (dev->flags & IFF_UP)
 843                         return -EBUSY;
 844                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
 845                        sizeof(dbt));
 846                 err = can_get_bittiming(dev, &dbt, priv->data_bittiming_const);
 847                 if (err)
 848                         return err;
 849                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
 850
 851                 if (priv->do_set_data_bittiming) {
 852                         /* Finally, set the bit-timing registers */
 853                         err = priv->do_set_data_bittiming(dev);
 854                         if (err)
 855                                 return err;
 856                 }
 857         }
 858
 859         return 0;
 860 }
 861
 862 static size_t can_get_size(const struct net_device *dev)
 863 {
 864         struct can_priv *priv = netdev_priv(dev);
 865         size_t size = 0;
 866
 867         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
 868                 size += nla_total_size(sizeof(struct can_bittiming));
 869         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
 870                 size += nla_total_size(sizeof(struct can_bittiming_const));
 871         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
 872         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
 873         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
 874         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
 875         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
 876                 size += nla_total_size(sizeof(struct can_berr_counter));
 877         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
 878                 size += nla_total_size(sizeof(struct can_bittiming));
 879         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
 880                 size += nla_total_size(sizeof(struct can_bittiming_const));
 881
 882         return size;
 883 }
 884
 885 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 886 {
 887         struct can_priv *priv = netdev_priv(dev);
 888         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
 889         struct can_berr_counter bec;
 890         enum can_state state = priv->state;
 891
 892         if (priv->do_get_state)
 893                 priv->do_get_state(dev, &state);
 894
 895         if ((priv->bittiming.bitrate &&
 896              nla_put(skb, IFLA_CAN_BITTIMING,
 897                      sizeof(priv->bittiming), &priv->bittiming)) ||
 898
 899             (priv->bittiming_const &&
 900              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
 901                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
 902
 903             nla_put(skb, IFLA_CAN_CLOCK, sizeof(cm), &priv->clock) ||
 904             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
 905             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
 906             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
 907
 908             (priv->do_get_berr_counter &&
 909              !priv->do_get_berr_counter(dev, &bec) &&
 910              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
 911
 912             (priv->data_bittiming.bitrate &&
 913              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
 914                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
 915
 916             (priv->data_bittiming_const &&
 917              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
 918                      sizeof(*priv->data_bittiming_const),
 919                      priv->data_bittiming_const)))
 920                 return -EMSGSIZE;
 921
 922         return 0;
 923 }
 924
 925 static size_t can_get_xstats_size(const struct net_device *dev)
 926 {
 927         return sizeof(struct can_device_stats);
 928 }
 929
 930 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
 931 {
 932         struct can_priv *priv = netdev_priv(dev);
 933
 934         if (nla_put(skb, IFLA_INFO_XSTATS,
 935                     sizeof(priv->can_stats), &priv->can_stats))
 936                 goto nla_put_failure;
 937         return 0;
 938
 939 nla_put_failure:
 940         return -EMSGSIZE;
 941 }
 942
 943 static int can_newlink(struct net *src_net, struct net_device *dev,
 944                        struct nlattr *tb[], struct nlattr *data[])
 945 {
 946         return -EOPNOTSUPP;
 947 }
 948
 949 static struct rtnl_link_ops can_link_ops __read_mostly = {
 950         .kind           = "can",
 951         .maxtype        = IFLA_CAN_MAX,
 952         .policy         = can_policy,
 953         .setup          = can_setup,
 954         .newlink        = can_newlink,
 955         .changelink     = can_changelink,
 956         .get_size       = can_get_size,
 957         .fill_info      = can_fill_info,
 958         .get_xstats_size = can_get_xstats_size,
 959         .fill_xstats    = can_fill_xstats,
 960 };
 961
 962 /*
 963  * Register the CAN network device
 964  */
 965 int register_candev(struct net_device *dev)
 966 {
 967         dev->rtnl_link_ops = &can_link_ops;
 968         return register_netdev(dev);
 969 }
 970 EXPORT_SYMBOL_GPL(register_candev);
 971
 972 /*
 973  * Unregister the CAN network device
 974  */
 975 void unregister_candev(struct net_device *dev)
 976 {
 977         unregister_netdev(dev);
 978 }
 979 EXPORT_SYMBOL_GPL(unregister_candev);
 980
 981 /*
 982  * Test if a network device is a candev based device
 983  * and return the can_priv* if so.
 984  */
 985 struct can_priv *safe_candev_priv(struct net_device *dev)
 986 {
 987         if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
 988                 return NULL;
 989
 990         return netdev_priv(dev);
 991 }
 992 EXPORT_SYMBOL_GPL(safe_candev_priv);
 993
 994 static __init int can_dev_init(void)
 995 {
 996         int err;
 997
 998         can_led_notifier_init();
 999
1000         err = rtnl_link_register(&can_link_ops);
1001         if (!err)
1002                 printk(KERN_INFO MOD_DESC "\n");
1003
1004         return err;
1005 }
1006 module_init(can_dev_init);
1007
1008 static __exit void can_dev_exit(void)
1009 {
1010         rtnl_link_unregister(&can_link_ops);
1011
1012         can_led_notifier_exit();
1013 }
1014 module_exit(can_dev_exit);
1015
1016 MODULE_ALIAS_RTNL_LINK("can");