kernel/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 /*
 427  * Get the skb from the stack and loop it back locally
 428  *
 429  * The function is typically called when the TX done interrupt
 430  * is handled in the device driver. The driver must protect
 431  * access to priv->echo_skb, if necessary.
 432  */
 433 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 434 {
 435         struct can_priv *priv = netdev_priv(dev);
 436
 437         BUG_ON(idx >= priv->echo_skb_max);
 438
 439         if (priv->echo_skb[idx]) {
 440                 struct sk_buff *skb = priv->echo_skb[idx];
 441                 struct can_frame *cf = (struct can_frame *)skb->data;
 442                 u8 dlc = cf->can_dlc;
 443
 444                 netif_rx(priv->echo_skb[idx]);
 445                 priv->echo_skb[idx] = NULL;
 446
 447                 return dlc;
 448         }
 449
 450         return 0;
 451 }
 452 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 453
 454 /*
 455   * Remove the skb from the stack and free it.
 456   *
 457   * The function is typically called when TX failed.
 458   */
 459 void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 460 {
 461         struct can_priv *priv = netdev_priv(dev);
 462
 463         BUG_ON(idx >= priv->echo_skb_max);
 464
 465         if (priv->echo_skb[idx]) {
 466                 dev_kfree_skb_any(priv->echo_skb[idx]);
 467                 priv->echo_skb[idx] = NULL;
 468         }
 469 }
 470 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 471
 472 /*
 473  * CAN device restart for bus-off recovery
 474  */
 475 static void can_restart(struct net_device *dev)
 476 {
 477         struct can_priv *priv = netdev_priv(dev);
 478         struct net_device_stats *stats = &dev->stats;
 479         struct sk_buff *skb;
 480         struct can_frame *cf;
 481         int err;
 482
 483         BUG_ON(netif_carrier_ok(dev));
 484
 485         /*
 486          * No synchronization needed because the device is bus-off and
 487          * no messages can come in or go out.
 488          */
 489         can_flush_echo_skb(dev);
 490
 491         /* send restart message upstream */
 492         skb = alloc_can_err_skb(dev, &cf);
 493         if (skb == NULL) {
 494                 err = -ENOMEM;
 495                 goto restart;
 496         }
 497         cf->can_id |= CAN_ERR_RESTARTED;
 498
 499         netif_rx(skb);
 500
 501         stats->rx_packets++;
 502         stats->rx_bytes += cf->can_dlc;
 503
 504 restart:
 505         netdev_dbg(dev, "restarted\n");
 506         priv->can_stats.restarts++;
 507
 508         /* Now restart the device */
 509         err = priv->do_set_mode(dev, CAN_MODE_START);
 510
 511         netif_carrier_on(dev);
 512         if (err)
 513                 netdev_err(dev, "Error %d during restart", err);
 514 }
 515
 516 static void can_restart_work(struct work_struct *work)
 517 {
 518         struct delayed_work *dwork = to_delayed_work(work);
 519         struct can_priv *priv = container_of(dwork, struct can_priv, restart_work);
 520
 521         can_restart(priv->dev);
 522 }
 523
 524 int can_restart_now(struct net_device *dev)
 525 {
 526         struct can_priv *priv = netdev_priv(dev);
 527
 528         /*
 529          * A manual restart is only permitted if automatic restart is
 530          * disabled and the device is in the bus-off state
 531          */
 532         if (priv->restart_ms)
 533                 return -EINVAL;
 534         if (priv->state != CAN_STATE_BUS_OFF)
 535                 return -EBUSY;
 536
 537         cancel_delayed_work_sync(&priv->restart_work);
 538         can_restart(dev);
 539
 540         return 0;
 541 }
 542
 543 /*
 544  * CAN bus-off
 545  *
 546  * This functions should be called when the device goes bus-off to
 547  * tell the netif layer that no more packets can be sent or received.
 548  * If enabled, a timer is started to trigger bus-off recovery.
 549  */
 550 void can_bus_off(struct net_device *dev)
 551 {
 552         struct can_priv *priv = netdev_priv(dev);
 553
 554         netdev_dbg(dev, "bus-off\n");
 555
 556         netif_carrier_off(dev);
 557
 558         if (priv->restart_ms)
 559                 schedule_delayed_work(&priv->restart_work,
 560                                       msecs_to_jiffies(priv->restart_ms));
 561 }
 562 EXPORT_SYMBOL_GPL(can_bus_off);
 563
 564 static void can_setup(struct net_device *dev)
 565 {
 566         dev->type = ARPHRD_CAN;
 567         dev->mtu = CAN_MTU;
 568         dev->hard_header_len = 0;
 569         dev->addr_len = 0;
 570         dev->tx_queue_len = 10;
 571
 572         /* New-style flags. */
 573         dev->flags = IFF_NOARP;
 574         dev->features = NETIF_F_HW_CSUM;
 575 }
 576
 577 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 578 {
 579         struct sk_buff *skb;
 580
 581         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 582                                sizeof(struct can_frame));
 583         if (unlikely(!skb))
 584                 return NULL;
 585
 586         skb->protocol = htons(ETH_P_CAN);
 587         skb->pkt_type = PACKET_BROADCAST;
 588         skb->ip_summed = CHECKSUM_UNNECESSARY;
 589
 590         skb_reset_mac_header(skb);
 591         skb_reset_network_header(skb);
 592         skb_reset_transport_header(skb);
 593
 594         can_skb_reserve(skb);
 595         can_skb_prv(skb)->ifindex = dev->ifindex;
 596         can_skb_prv(skb)->skbcnt = 0;
 597
 598         *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
 599         memset(*cf, 0, sizeof(struct can_frame));
 600
 601         return skb;
 602 }
 603 EXPORT_SYMBOL_GPL(alloc_can_skb);
 604
 605 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 606                                 struct canfd_frame **cfd)
 607 {
 608         struct sk_buff *skb;
 609
 610         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 611                                sizeof(struct canfd_frame));
 612         if (unlikely(!skb))
 613                 return NULL;
 614
 615         skb->protocol = htons(ETH_P_CANFD);
 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         *cfd = (struct canfd_frame *)skb_put(skb, sizeof(struct canfd_frame));
 628         memset(*cfd, 0, sizeof(struct canfd_frame));
 629
 630         return skb;
 631 }
 632 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 633
 634 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 635 {
 636         struct sk_buff *skb;
 637
 638         skb = alloc_can_skb(dev, cf);
 639         if (unlikely(!skb))
 640                 return NULL;
 641
 642         (*cf)->can_id = CAN_ERR_FLAG;
 643         (*cf)->can_dlc = CAN_ERR_DLC;
 644
 645         return skb;
 646 }
 647 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 648
 649 /*
 650  * Allocate and setup space for the CAN network device
 651  */
 652 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
 653 {
 654         struct net_device *dev;
 655         struct can_priv *priv;
 656         int size;
 657
 658         if (echo_skb_max)
 659                 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
 660                         echo_skb_max * sizeof(struct sk_buff *);
 661         else
 662                 size = sizeof_priv;
 663
 664         dev = alloc_netdev(size, "can%d", NET_NAME_UNKNOWN, can_setup);
 665         if (!dev)
 666                 return NULL;
 667
 668         priv = netdev_priv(dev);
 669         priv->dev = dev;
 670
 671         if (echo_skb_max) {
 672                 priv->echo_skb_max = echo_skb_max;
 673                 priv->echo_skb = (void *)priv +
 674                         ALIGN(sizeof_priv, sizeof(struct sk_buff *));
 675         }
 676
 677         priv->state = CAN_STATE_STOPPED;
 678
 679         INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
 680
 681         return dev;
 682 }
 683 EXPORT_SYMBOL_GPL(alloc_candev);
 684
 685 /*
 686  * Free space of the CAN network device
 687  */
 688 void free_candev(struct net_device *dev)
 689 {
 690         free_netdev(dev);
 691 }
 692 EXPORT_SYMBOL_GPL(free_candev);
 693
 694 /*
 695  * changing MTU and control mode for CAN/CANFD devices
 696  */
 697 int can_change_mtu(struct net_device *dev, int new_mtu)
 698 {
 699         struct can_priv *priv = netdev_priv(dev);
 700
 701         /* Do not allow changing the MTU while running */
 702         if (dev->flags & IFF_UP)
 703                 return -EBUSY;
 704
 705         /* allow change of MTU according to the CANFD ability of the device */
 706         switch (new_mtu) {
 707         case CAN_MTU:
 708                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 709                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 710                         return -EINVAL;
 711
 712                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 713                 break;
 714
 715         case CANFD_MTU:
 716                 /* check for potential CANFD ability */
 717                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 718                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 719                         return -EINVAL;
 720
 721                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 722                 break;
 723
 724         default:
 725                 return -EINVAL;
 726         }
 727
 728         dev->mtu = new_mtu;
 729         return 0;
 730 }
 731 EXPORT_SYMBOL_GPL(can_change_mtu);
 732
 733 /*
 734  * Common open function when the device gets opened.
 735  *
 736  * This function should be called in the open function of the device
 737  * driver.
 738  */
 739 int open_candev(struct net_device *dev)
 740 {
 741         struct can_priv *priv = netdev_priv(dev);
 742
 743         if (!priv->bittiming.bitrate) {
 744                 netdev_err(dev, "bit-timing not yet defined\n");
 745                 return -EINVAL;
 746         }
 747
 748         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 749         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 750             (!priv->data_bittiming.bitrate ||
 751              (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
 752                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 753                 return -EINVAL;
 754         }
 755
 756         /* Switch carrier on if device was stopped while in bus-off state */
 757         if (!netif_carrier_ok(dev))
 758                 netif_carrier_on(dev);
 759
 760         return 0;
 761 }
 762 EXPORT_SYMBOL_GPL(open_candev);
 763
 764 /*
 765  * Common close function for cleanup before the device gets closed.
 766  *
 767  * This function should be called in the close function of the device
 768  * driver.
 769  */
 770 void close_candev(struct net_device *dev)
 771 {
 772         struct can_priv *priv = netdev_priv(dev);
 773
 774         cancel_delayed_work_sync(&priv->restart_work);
 775         can_flush_echo_skb(dev);
 776 }
 777 EXPORT_SYMBOL_GPL(close_candev);
 778
 779 /*
 780  * CAN netlink interface
 781  */
 782 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 783         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 784         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 785         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 786         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 787         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 788         [IFLA_CAN_BITTIMING_CONST]
 789                                 = { .len = sizeof(struct can_bittiming_const) },
 790         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 791         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 792         [IFLA_CAN_DATA_BITTIMING]
 793                                 = { .len = sizeof(struct can_bittiming) },
 794         [IFLA_CAN_DATA_BITTIMING_CONST]
 795                                 = { .len = sizeof(struct can_bittiming_const) },
 796 };
 797
 798 static int can_validate(struct nlattr *tb[], struct nlattr *data[])
 799 {
 800         bool is_can_fd = false;
 801
 802         /* Make sure that valid CAN FD configurations always consist of
 803          * - nominal/arbitration bittiming
 804          * - data bittiming
 805          * - control mode with CAN_CTRLMODE_FD set
 806          */
 807
 808         if (!data)
 809                 return 0;
 810
 811         if (data[IFLA_CAN_CTRLMODE]) {
 812                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 813
 814                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 815         }
 816
 817         if (is_can_fd) {
 818                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 819                         return -EOPNOTSUPP;
 820         }
 821
 822         if (data[IFLA_CAN_DATA_BITTIMING]) {
 823                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 824                         return -EOPNOTSUPP;
 825         }
 826
 827         return 0;
 828 }
 829
 830 static int can_changelink(struct net_device *dev,
 831                           struct nlattr *tb[], struct nlattr *data[])
 832 {
 833         struct can_priv *priv = netdev_priv(dev);
 834         int err;
 835
 836         /* We need synchronization with dev->stop() */
 837         ASSERT_RTNL();
 838
 839         if (data[IFLA_CAN_BITTIMING]) {
 840                 struct can_bittiming bt;
 841
 842                 /* Do not allow changing bittiming while running */
 843                 if (dev->flags & IFF_UP)
 844                         return -EBUSY;
 845                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 846                 err = can_get_bittiming(dev, &bt, priv->bittiming_const);
 847                 if (err)
 848                         return err;
 849                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 850
 851                 if (priv->do_set_bittiming) {
 852                         /* Finally, set the bit-timing registers */
 853                         err = priv->do_set_bittiming(dev);
 854                         if (err)
 855                                 return err;
 856                 }
 857         }
 858
 859         if (data[IFLA_CAN_CTRLMODE]) {
 860                 struct can_ctrlmode *cm;
 861                 u32 ctrlstatic;
 862                 u32 maskedflags;
 863
 864                 /* Do not allow changing controller mode while running */
 865                 if (dev->flags & IFF_UP)
 866                         return -EBUSY;
 867                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 868                 ctrlstatic = priv->ctrlmode_static;
 869                 maskedflags = cm->flags & cm->mask;
 870
 871                 /* check whether provided bits are allowed to be passed */
 872                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
 873                         return -EOPNOTSUPP;
 874
 875                 /* do not check for static fd-non-iso if 'fd' is disabled */
 876                 if (!(maskedflags & CAN_CTRLMODE_FD))
 877                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
 878
 879                 /* make sure static options are provided by configuration */
 880                 if ((maskedflags & ctrlstatic) != ctrlstatic)
 881                         return -EOPNOTSUPP;
 882
 883                 /* clear bits to be modified and copy the flag values */
 884                 priv->ctrlmode &= ~cm->mask;
 885                 priv->ctrlmode |= maskedflags;
 886
 887                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
 888                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
 889                         dev->mtu = CANFD_MTU;
 890                 else
 891                         dev->mtu = CAN_MTU;
 892         }
 893
 894         if (data[IFLA_CAN_RESTART_MS]) {
 895                 /* Do not allow changing restart delay while running */
 896                 if (dev->flags & IFF_UP)
 897                         return -EBUSY;
 898                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
 899         }
 900
 901         if (data[IFLA_CAN_RESTART]) {
 902                 /* Do not allow a restart while not running */
 903                 if (!(dev->flags & IFF_UP))
 904                         return -EINVAL;
 905                 err = can_restart_now(dev);
 906                 if (err)
 907                         return err;
 908         }
 909
 910         if (data[IFLA_CAN_DATA_BITTIMING]) {
 911                 struct can_bittiming dbt;
 912
 913                 /* Do not allow changing bittiming while running */
 914                 if (dev->flags & IFF_UP)
 915                         return -EBUSY;
 916                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
 917                        sizeof(dbt));
 918                 err = can_get_bittiming(dev, &dbt, priv->data_bittiming_const);
 919                 if (err)
 920                         return err;
 921                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
 922
 923                 if (priv->do_set_data_bittiming) {
 924                         /* Finally, set the bit-timing registers */
 925                         err = priv->do_set_data_bittiming(dev);
 926                         if (err)
 927                                 return err;
 928                 }
 929         }
 930
 931         return 0;
 932 }
 933
 934 static size_t can_get_size(const struct net_device *dev)
 935 {
 936         struct can_priv *priv = netdev_priv(dev);
 937         size_t size = 0;
 938
 939         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
 940                 size += nla_total_size(sizeof(struct can_bittiming));
 941         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
 942                 size += nla_total_size(sizeof(struct can_bittiming_const));
 943         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
 944         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
 945         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
 946         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
 947         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
 948                 size += nla_total_size(sizeof(struct can_berr_counter));
 949         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
 950                 size += nla_total_size(sizeof(struct can_bittiming));
 951         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
 952                 size += nla_total_size(sizeof(struct can_bittiming_const));
 953
 954         return size;
 955 }
 956
 957 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 958 {
 959         struct can_priv *priv = netdev_priv(dev);
 960         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
 961         struct can_berr_counter bec;
 962         enum can_state state = priv->state;
 963
 964         if (priv->do_get_state)
 965                 priv->do_get_state(dev, &state);
 966
 967         if ((priv->bittiming.bitrate &&
 968              nla_put(skb, IFLA_CAN_BITTIMING,
 969                      sizeof(priv->bittiming), &priv->bittiming)) ||
 970
 971             (priv->bittiming_const &&
 972              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
 973                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
 974
 975             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
 976             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
 977             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
 978             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
 979
 980             (priv->do_get_berr_counter &&
 981              !priv->do_get_berr_counter(dev, &bec) &&
 982              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
 983
 984             (priv->data_bittiming.bitrate &&
 985              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
 986                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
 987
 988             (priv->data_bittiming_const &&
 989              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
 990                      sizeof(*priv->data_bittiming_const),
 991                      priv->data_bittiming_const)))
 992                 return -EMSGSIZE;
 993
 994         return 0;
 995 }
 996
 997 static size_t can_get_xstats_size(const struct net_device *dev)
 998 {
 999         return sizeof(struct can_device_stats);
1000 }
1001
1002 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1003 {
1004         struct can_priv *priv = netdev_priv(dev);
1005
1006         if (nla_put(skb, IFLA_INFO_XSTATS,
1007                     sizeof(priv->can_stats), &priv->can_stats))
1008                 goto nla_put_failure;
1009         return 0;
1010
1011 nla_put_failure:
1012         return -EMSGSIZE;
1013 }
1014
1015 static int can_newlink(struct net *src_net, struct net_device *dev,
1016                        struct nlattr *tb[], struct nlattr *data[])
1017 {
1018         return -EOPNOTSUPP;
1019 }
1020
1021 static void can_dellink(struct net_device *dev, struct list_head *head)
1022 {
1023         return;
1024 }
1025
1026 static struct rtnl_link_ops can_link_ops __read_mostly = {
1027         .kind           = "can",
1028         .maxtype        = IFLA_CAN_MAX,
1029         .policy         = can_policy,
1030         .setup          = can_setup,
1031         .validate       = can_validate,
1032         .newlink        = can_newlink,
1033         .changelink     = can_changelink,
1034         .dellink        = can_dellink,
1035         .get_size       = can_get_size,
1036         .fill_info      = can_fill_info,
1037         .get_xstats_size = can_get_xstats_size,
1038         .fill_xstats    = can_fill_xstats,
1039 };
1040
1041 /*
1042  * Register the CAN network device
1043  */
1044 int register_candev(struct net_device *dev)
1045 {
1046         dev->rtnl_link_ops = &can_link_ops;
1047         return register_netdev(dev);
1048 }
1049 EXPORT_SYMBOL_GPL(register_candev);
1050
1051 /*
1052  * Unregister the CAN network device
1053  */
1054 void unregister_candev(struct net_device *dev)
1055 {
1056         unregister_netdev(dev);
1057 }
1058 EXPORT_SYMBOL_GPL(unregister_candev);
1059
1060 /*
1061  * Test if a network device is a candev based device
1062  * and return the can_priv* if so.
1063  */
1064 struct can_priv *safe_candev_priv(struct net_device *dev)
1065 {
1066         if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1067                 return NULL;
1068
1069         return netdev_priv(dev);
1070 }
1071 EXPORT_SYMBOL_GPL(safe_candev_priv);
1072
1073 static __init int can_dev_init(void)
1074 {
1075         int err;
1076
1077         can_led_notifier_init();
1078
1079         err = rtnl_link_register(&can_link_ops);
1080         if (!err)
1081                 printk(KERN_INFO MOD_DESC "\n");
1082
1083         return err;
1084 }
1085 module_init(can_dev_init);
1086
1087 static __exit void can_dev_exit(void)
1088 {
1089         rtnl_link_unregister(&can_link_ops);
1090
1091         can_led_notifier_exit();
1092 }
1093 module_exit(can_dev_exit);
1094
1095 MODULE_ALIAS_RTNL_LINK("can");