drivers/net/can/dev.c

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