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 #define CAN_CALC_SYNC_SEG 1
  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_sample_point(const struct can_bittiming_const *btc,
  88                           unsigned int sample_point_nominal, unsigned int tseg,
  89                           unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
  90                           unsigned int *sample_point_error_ptr)
  91 {
  92         unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
  93         unsigned int sample_point, best_sample_point = 0;
  94         unsigned int tseg1, tseg2;
  95         int i;
  96
  97         for (i = 0; i <= 1; i++) {
  98                 tseg2 = tseg + CAN_CALC_SYNC_SEG - (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) / 1000 - i;
  99                 tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
 100                 tseg1 = tseg - tseg2;
 101                 if (tseg1 > btc->tseg1_max) {
 102                         tseg1 = btc->tseg1_max;
 103                         tseg2 = tseg - tseg1;
 104                 }
 105
 106                 sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) / (tseg + CAN_CALC_SYNC_SEG);
 107                 sample_point_error = abs(sample_point_nominal - sample_point);
 108
 109                 if ((sample_point <= sample_point_nominal) && (sample_point_error < best_sample_point_error)) {
 110                         best_sample_point = sample_point;
 111                         best_sample_point_error = sample_point_error;
 112                         *tseg1_ptr = tseg1;
 113                         *tseg2_ptr = tseg2;
 114                 }
 115         }
 116
 117         if (sample_point_error_ptr)
 118                 *sample_point_error_ptr = best_sample_point_error;
 119
 120         return best_sample_point;
 121 }
 122
 123 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 124                               const struct can_bittiming_const *btc)
 125 {
 126         struct can_priv *priv = netdev_priv(dev);
 127         unsigned int bitrate;                   /* current bitrate */
 128         unsigned int bitrate_error;             /* difference between current and nominal value */
 129         unsigned int best_bitrate_error = UINT_MAX;
 130         unsigned int sample_point_error;        /* difference between current and nominal value */
 131         unsigned int best_sample_point_error = UINT_MAX;
 132         unsigned int sample_point_nominal;      /* nominal sample point */
 133         unsigned int best_tseg = 0;             /* current best value for tseg */
 134         unsigned int best_brp = 0;              /* current best value for brp */
 135         unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
 136         u64 v64;
 137
 138         /* Use CiA recommended sample points */
 139         if (bt->sample_point) {
 140                 sample_point_nominal = bt->sample_point;
 141         } else {
 142                 if (bt->bitrate > 800000)
 143                         sample_point_nominal = 750;
 144                 else if (bt->bitrate > 500000)
 145                         sample_point_nominal = 800;
 146                 else
 147                         sample_point_nominal = 875;
 148         }
 149
 150         /* tseg even = round down, odd = round up */
 151         for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
 152              tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
 153                 tsegall = CAN_CALC_SYNC_SEG + tseg / 2;
 154
 155                 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
 156                 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
 157
 158                 /* choose brp step which is possible in system */
 159                 brp = (brp / btc->brp_inc) * btc->brp_inc;
 160                 if ((brp < btc->brp_min) || (brp > btc->brp_max))
 161                         continue;
 162
 163                 bitrate = priv->clock.freq / (brp * tsegall);
 164                 bitrate_error = abs(bt->bitrate - bitrate);
 165
 166                 /* tseg brp biterror */
 167                 if (bitrate_error > best_bitrate_error)
 168                         continue;
 169
 170                 /* reset sample point error if we have a better bitrate */
 171                 if (bitrate_error < best_bitrate_error)
 172                         best_sample_point_error = UINT_MAX;
 173
 174                 can_update_sample_point(btc, sample_point_nominal, tseg / 2, &tseg1, &tseg2, &sample_point_error);
 175                 if (sample_point_error > best_sample_point_error)
 176                         continue;
 177
 178                 best_sample_point_error = sample_point_error;
 179                 best_bitrate_error = bitrate_error;
 180                 best_tseg = tseg / 2;
 181                 best_brp = brp;
 182
 183                 if (bitrate_error == 0 && sample_point_error == 0)
 184                         break;
 185         }
 186
 187         if (best_bitrate_error) {
 188                 /* Error in one-tenth of a percent */
 189                 v64 = (u64)best_bitrate_error * 1000;
 190                 do_div(v64, bt->bitrate);
 191                 bitrate_error = (u32)v64;
 192                 if (bitrate_error > CAN_CALC_MAX_ERROR) {
 193                         netdev_err(dev,
 194                                    "bitrate error %d.%d%% too high\n",
 195                                    bitrate_error / 10, bitrate_error % 10);
 196                         return -EDOM;
 197                 }
 198                 netdev_warn(dev, "bitrate error %d.%d%%\n",
 199                             bitrate_error / 10, bitrate_error % 10);
 200         }
 201
 202         /* real sample point */
 203         bt->sample_point = can_update_sample_point(btc, sample_point_nominal, best_tseg,
 204                                           &tseg1, &tseg2, NULL);
 205
 206         v64 = (u64)best_brp * 1000 * 1000 * 1000;
 207         do_div(v64, priv->clock.freq);
 208         bt->tq = (u32)v64;
 209         bt->prop_seg = tseg1 / 2;
 210         bt->phase_seg1 = tseg1 - bt->prop_seg;
 211         bt->phase_seg2 = tseg2;
 212
 213         /* check for sjw user settings */
 214         if (!bt->sjw || !btc->sjw_max) {
 215                 bt->sjw = 1;
 216         } else {
 217                 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
 218                 if (bt->sjw > btc->sjw_max)
 219                         bt->sjw = btc->sjw_max;
 220                 /* bt->sjw must not be higher than tseg2 */
 221                 if (tseg2 < bt->sjw)
 222                         bt->sjw = tseg2;
 223         }
 224
 225         bt->brp = best_brp;
 226
 227         /* real bitrate */
 228         bt->bitrate = priv->clock.freq / (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2));
 229
 230         return 0;
 231 }
 232 #else /* !CONFIG_CAN_CALC_BITTIMING */
 233 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 234                               const struct can_bittiming_const *btc)
 235 {
 236         netdev_err(dev, "bit-timing calculation not available\n");
 237         return -EINVAL;
 238 }
 239 #endif /* CONFIG_CAN_CALC_BITTIMING */
 240
 241 /*
 242  * Checks the validity of the specified bit-timing parameters prop_seg,
 243  * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
 244  * prescaler value brp. You can find more information in the header
 245  * file linux/can/netlink.h.
 246  */
 247 static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
 248                                const struct can_bittiming_const *btc)
 249 {
 250         struct can_priv *priv = netdev_priv(dev);
 251         int tseg1, alltseg;
 252         u64 brp64;
 253
 254         tseg1 = bt->prop_seg + bt->phase_seg1;
 255         if (!bt->sjw)
 256                 bt->sjw = 1;
 257         if (bt->sjw > btc->sjw_max ||
 258             tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
 259             bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
 260                 return -ERANGE;
 261
 262         brp64 = (u64)priv->clock.freq * (u64)bt->tq;
 263         if (btc->brp_inc > 1)
 264                 do_div(brp64, btc->brp_inc);
 265         brp64 += 500000000UL - 1;
 266         do_div(brp64, 1000000000UL); /* the practicable BRP */
 267         if (btc->brp_inc > 1)
 268                 brp64 *= btc->brp_inc;
 269         bt->brp = (u32)brp64;
 270
 271         if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
 272                 return -EINVAL;
 273
 274         alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
 275         bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
 276         bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
 277
 278         return 0;
 279 }
 280
 281 static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
 282                              const struct can_bittiming_const *btc)
 283 {
 284         int err;
 285
 286         /* Check if the CAN device has bit-timing parameters */
 287         if (!btc)
 288                 return -EOPNOTSUPP;
 289
 290         /*
 291          * Depending on the given can_bittiming parameter structure the CAN
 292          * timing parameters are calculated based on the provided bitrate OR
 293          * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
 294          * provided directly which are then checked and fixed up.
 295          */
 296         if (!bt->tq && bt->bitrate)
 297                 err = can_calc_bittiming(dev, bt, btc);
 298         else if (bt->tq && !bt->bitrate)
 299                 err = can_fixup_bittiming(dev, bt, btc);
 300         else
 301                 err = -EINVAL;
 302
 303         return err;
 304 }
 305
 306 static void can_update_state_error_stats(struct net_device *dev,
 307                                          enum can_state new_state)
 308 {
 309         struct can_priv *priv = netdev_priv(dev);
 310
 311         if (new_state <= priv->state)
 312                 return;
 313
 314         switch (new_state) {
 315         case CAN_STATE_ERROR_WARNING:
 316                 priv->can_stats.error_warning++;
 317                 break;
 318         case CAN_STATE_ERROR_PASSIVE:
 319                 priv->can_stats.error_passive++;
 320                 break;
 321         case CAN_STATE_BUS_OFF:
 322                 priv->can_stats.bus_off++;
 323                 break;
 324         default:
 325                 break;
 326         }
 327 }
 328
 329 static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
 330 {
 331         switch (state) {
 332         case CAN_STATE_ERROR_ACTIVE:
 333                 return CAN_ERR_CRTL_ACTIVE;
 334         case CAN_STATE_ERROR_WARNING:
 335                 return CAN_ERR_CRTL_TX_WARNING;
 336         case CAN_STATE_ERROR_PASSIVE:
 337                 return CAN_ERR_CRTL_TX_PASSIVE;
 338         default:
 339                 return 0;
 340         }
 341 }
 342
 343 static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
 344 {
 345         switch (state) {
 346         case CAN_STATE_ERROR_ACTIVE:
 347                 return CAN_ERR_CRTL_ACTIVE;
 348         case CAN_STATE_ERROR_WARNING:
 349                 return CAN_ERR_CRTL_RX_WARNING;
 350         case CAN_STATE_ERROR_PASSIVE:
 351                 return CAN_ERR_CRTL_RX_PASSIVE;
 352         default:
 353                 return 0;
 354         }
 355 }
 356
 357 void can_change_state(struct net_device *dev, struct can_frame *cf,
 358                       enum can_state tx_state, enum can_state rx_state)
 359 {
 360         struct can_priv *priv = netdev_priv(dev);
 361         enum can_state new_state = max(tx_state, rx_state);
 362
 363         if (unlikely(new_state == priv->state)) {
 364                 netdev_warn(dev, "%s: oops, state did not change", __func__);
 365                 return;
 366         }
 367
 368         netdev_dbg(dev, "New error state: %d\n", new_state);
 369
 370         can_update_state_error_stats(dev, new_state);
 371         priv->state = new_state;
 372
 373         if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
 374                 cf->can_id |= CAN_ERR_BUSOFF;
 375                 return;
 376         }
 377
 378         cf->can_id |= CAN_ERR_CRTL;
 379         cf->data[1] |= tx_state >= rx_state ?
 380                        can_tx_state_to_frame(dev, tx_state) : 0;
 381         cf->data[1] |= tx_state <= rx_state ?
 382                        can_rx_state_to_frame(dev, rx_state) : 0;
 383 }
 384 EXPORT_SYMBOL_GPL(can_change_state);
 385
 386 /*
 387  * Local echo of CAN messages
 388  *
 389  * CAN network devices *should* support a local echo functionality
 390  * (see Documentation/networking/can.txt). To test the handling of CAN
 391  * interfaces that do not support the local echo both driver types are
 392  * implemented. In the case that the driver does not support the echo
 393  * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
 394  * to perform the echo as a fallback solution.
 395  */
 396 static void can_flush_echo_skb(struct net_device *dev)
 397 {
 398         struct can_priv *priv = netdev_priv(dev);
 399         struct net_device_stats *stats = &dev->stats;
 400         int i;
 401
 402         for (i = 0; i < priv->echo_skb_max; i++) {
 403                 if (priv->echo_skb[i]) {
 404                         kfree_skb(priv->echo_skb[i]);
 405                         priv->echo_skb[i] = NULL;
 406                         stats->tx_dropped++;
 407                         stats->tx_aborted_errors++;
 408                 }
 409         }
 410 }
 411
 412 /*
 413  * Put the skb on the stack to be looped backed locally lateron
 414  *
 415  * The function is typically called in the start_xmit function
 416  * of the device driver. The driver must protect access to
 417  * priv->echo_skb, if necessary.
 418  */
 419 void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 420                       unsigned int idx)
 421 {
 422         struct can_priv *priv = netdev_priv(dev);
 423
 424         BUG_ON(idx >= priv->echo_skb_max);
 425
 426         /* check flag whether this packet has to be looped back */
 427         if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
 428             (skb->protocol != htons(ETH_P_CAN) &&
 429              skb->protocol != htons(ETH_P_CANFD))) {
 430                 kfree_skb(skb);
 431                 return;
 432         }
 433
 434         if (!priv->echo_skb[idx]) {
 435
 436                 skb = can_create_echo_skb(skb);
 437                 if (!skb)
 438                         return;
 439
 440                 /* make settings for echo to reduce code in irq context */
 441                 skb->pkt_type = PACKET_BROADCAST;
 442                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 443                 skb->dev = dev;
 444
 445                 /* save this skb for tx interrupt echo handling */
 446                 priv->echo_skb[idx] = skb;
 447         } else {
 448                 /* locking problem with netif_stop_queue() ?? */
 449                 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
 450                 kfree_skb(skb);
 451         }
 452 }
 453 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 454
 455 /*
 456  * Get the skb from the stack and loop it back locally
 457  *
 458  * The function is typically called when the TX done interrupt
 459  * is handled in the device driver. The driver must protect
 460  * access to priv->echo_skb, if necessary.
 461  */
 462 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 463 {
 464         struct can_priv *priv = netdev_priv(dev);
 465
 466         BUG_ON(idx >= priv->echo_skb_max);
 467
 468         if (priv->echo_skb[idx]) {
 469                 struct sk_buff *skb = priv->echo_skb[idx];
 470                 struct can_frame *cf = (struct can_frame *)skb->data;
 471                 u8 dlc = cf->can_dlc;
 472
 473                 netif_rx(priv->echo_skb[idx]);
 474                 priv->echo_skb[idx] = NULL;
 475
 476                 return dlc;
 477         }
 478
 479         return 0;
 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(unsigned long data)
 505 {
 506         struct net_device *dev = (struct net_device *)data;
 507         struct can_priv *priv = netdev_priv(dev);
 508         struct net_device_stats *stats = &dev->stats;
 509         struct sk_buff *skb;
 510         struct can_frame *cf;
 511         int err;
 512
 513         BUG_ON(netif_carrier_ok(dev));
 514
 515         /*
 516          * No synchronization needed because the device is bus-off and
 517          * no messages can come in or go out.
 518          */
 519         can_flush_echo_skb(dev);
 520
 521         /* send restart message upstream */
 522         skb = alloc_can_err_skb(dev, &cf);
 523         if (skb == NULL) {
 524                 err = -ENOMEM;
 525                 goto restart;
 526         }
 527         cf->can_id |= CAN_ERR_RESTARTED;
 528
 529         netif_rx(skb);
 530
 531         stats->rx_packets++;
 532         stats->rx_bytes += cf->can_dlc;
 533
 534 restart:
 535         netdev_dbg(dev, "restarted\n");
 536         priv->can_stats.restarts++;
 537
 538         /* Now restart the device */
 539         err = priv->do_set_mode(dev, CAN_MODE_START);
 540
 541         netif_carrier_on(dev);
 542         if (err)
 543                 netdev_err(dev, "Error %d during restart", err);
 544 }
 545
 546 int can_restart_now(struct net_device *dev)
 547 {
 548         struct can_priv *priv = netdev_priv(dev);
 549
 550         /*
 551          * A manual restart is only permitted if automatic restart is
 552          * disabled and the device is in the bus-off state
 553          */
 554         if (priv->restart_ms)
 555                 return -EINVAL;
 556         if (priv->state != CAN_STATE_BUS_OFF)
 557                 return -EBUSY;
 558
 559         /* Runs as soon as possible in the timer context */
 560         mod_timer(&priv->restart_timer, jiffies);
 561
 562         return 0;
 563 }
 564
 565 /*
 566  * CAN bus-off
 567  *
 568  * This functions should be called when the device goes bus-off to
 569  * tell the netif layer that no more packets can be sent or received.
 570  * If enabled, a timer is started to trigger bus-off recovery.
 571  */
 572 void can_bus_off(struct net_device *dev)
 573 {
 574         struct can_priv *priv = netdev_priv(dev);
 575
 576         netdev_dbg(dev, "bus-off\n");
 577
 578         netif_carrier_off(dev);
 579
 580         if (priv->restart_ms)
 581                 mod_timer(&priv->restart_timer,
 582                           jiffies + (priv->restart_ms * HZ) / 1000);
 583 }
 584 EXPORT_SYMBOL_GPL(can_bus_off);
 585
 586 static void can_setup(struct net_device *dev)
 587 {
 588         dev->type = ARPHRD_CAN;
 589         dev->mtu = CAN_MTU;
 590         dev->hard_header_len = 0;
 591         dev->addr_len = 0;
 592         dev->tx_queue_len = 10;
 593
 594         /* New-style flags. */
 595         dev->flags = IFF_NOARP;
 596         dev->features = NETIF_F_HW_CSUM;
 597 }
 598
 599 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 600 {
 601         struct sk_buff *skb;
 602
 603         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 604                                sizeof(struct can_frame));
 605         if (unlikely(!skb))
 606                 return NULL;
 607
 608         skb->protocol = htons(ETH_P_CAN);
 609         skb->pkt_type = PACKET_BROADCAST;
 610         skb->ip_summed = CHECKSUM_UNNECESSARY;
 611
 612         skb_reset_mac_header(skb);
 613         skb_reset_network_header(skb);
 614         skb_reset_transport_header(skb);
 615
 616         can_skb_reserve(skb);
 617         can_skb_prv(skb)->ifindex = dev->ifindex;
 618         can_skb_prv(skb)->skbcnt = 0;
 619
 620         *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
 621         memset(*cf, 0, sizeof(struct can_frame));
 622
 623         return skb;
 624 }
 625 EXPORT_SYMBOL_GPL(alloc_can_skb);
 626
 627 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 628                                 struct canfd_frame **cfd)
 629 {
 630         struct sk_buff *skb;
 631
 632         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 633                                sizeof(struct canfd_frame));
 634         if (unlikely(!skb))
 635                 return NULL;
 636
 637         skb->protocol = htons(ETH_P_CANFD);
 638         skb->pkt_type = PACKET_BROADCAST;
 639         skb->ip_summed = CHECKSUM_UNNECESSARY;
 640
 641         skb_reset_mac_header(skb);
 642         skb_reset_network_header(skb);
 643         skb_reset_transport_header(skb);
 644
 645         can_skb_reserve(skb);
 646         can_skb_prv(skb)->ifindex = dev->ifindex;
 647         can_skb_prv(skb)->skbcnt = 0;
 648
 649         *cfd = (struct canfd_frame *)skb_put(skb, sizeof(struct canfd_frame));
 650         memset(*cfd, 0, sizeof(struct canfd_frame));
 651
 652         return skb;
 653 }
 654 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 655
 656 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 657 {
 658         struct sk_buff *skb;
 659
 660         skb = alloc_can_skb(dev, cf);
 661         if (unlikely(!skb))
 662                 return NULL;
 663
 664         (*cf)->can_id = CAN_ERR_FLAG;
 665         (*cf)->can_dlc = CAN_ERR_DLC;
 666
 667         return skb;
 668 }
 669 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 670
 671 /*
 672  * Allocate and setup space for the CAN network device
 673  */
 674 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
 675 {
 676         struct net_device *dev;
 677         struct can_priv *priv;
 678         int size;
 679
 680         if (echo_skb_max)
 681                 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
 682                         echo_skb_max * sizeof(struct sk_buff *);
 683         else
 684                 size = sizeof_priv;
 685
 686         dev = alloc_netdev(size, "can%d", NET_NAME_UNKNOWN, can_setup);
 687         if (!dev)
 688                 return NULL;
 689
 690         priv = netdev_priv(dev);
 691
 692         if (echo_skb_max) {
 693                 priv->echo_skb_max = echo_skb_max;
 694                 priv->echo_skb = (void *)priv +
 695                         ALIGN(sizeof_priv, sizeof(struct sk_buff *));
 696         }
 697
 698         priv->state = CAN_STATE_STOPPED;
 699
 700         init_timer(&priv->restart_timer);
 701
 702         return dev;
 703 }
 704 EXPORT_SYMBOL_GPL(alloc_candev);
 705
 706 /*
 707  * Free space of the CAN network device
 708  */
 709 void free_candev(struct net_device *dev)
 710 {
 711         free_netdev(dev);
 712 }
 713 EXPORT_SYMBOL_GPL(free_candev);
 714
 715 /*
 716  * changing MTU and control mode for CAN/CANFD devices
 717  */
 718 int can_change_mtu(struct net_device *dev, int new_mtu)
 719 {
 720         struct can_priv *priv = netdev_priv(dev);
 721
 722         /* Do not allow changing the MTU while running */
 723         if (dev->flags & IFF_UP)
 724                 return -EBUSY;
 725
 726         /* allow change of MTU according to the CANFD ability of the device */
 727         switch (new_mtu) {
 728         case CAN_MTU:
 729                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 730                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 731                         return -EINVAL;
 732
 733                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 734                 break;
 735
 736         case CANFD_MTU:
 737                 /* check for potential CANFD ability */
 738                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 739                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 740                         return -EINVAL;
 741
 742                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 743                 break;
 744
 745         default:
 746                 return -EINVAL;
 747         }
 748
 749         dev->mtu = new_mtu;
 750         return 0;
 751 }
 752 EXPORT_SYMBOL_GPL(can_change_mtu);
 753
 754 /*
 755  * Common open function when the device gets opened.
 756  *
 757  * This function should be called in the open function of the device
 758  * driver.
 759  */
 760 int open_candev(struct net_device *dev)
 761 {
 762         struct can_priv *priv = netdev_priv(dev);
 763
 764         if (!priv->bittiming.bitrate) {
 765                 netdev_err(dev, "bit-timing not yet defined\n");
 766                 return -EINVAL;
 767         }
 768
 769         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 770         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 771             (!priv->data_bittiming.bitrate ||
 772              (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
 773                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 774                 return -EINVAL;
 775         }
 776
 777         /* Switch carrier on if device was stopped while in bus-off state */
 778         if (!netif_carrier_ok(dev))
 779                 netif_carrier_on(dev);
 780
 781         setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
 782
 783         return 0;
 784 }
 785 EXPORT_SYMBOL_GPL(open_candev);
 786
 787 /*
 788  * Common close function for cleanup before the device gets closed.
 789  *
 790  * This function should be called in the close function of the device
 791  * driver.
 792  */
 793 void close_candev(struct net_device *dev)
 794 {
 795         struct can_priv *priv = netdev_priv(dev);
 796
 797         del_timer_sync(&priv->restart_timer);
 798         can_flush_echo_skb(dev);
 799 }
 800 EXPORT_SYMBOL_GPL(close_candev);
 801
 802 /*
 803  * CAN netlink interface
 804  */
 805 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 806         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 807         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 808         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 809         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 810         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 811         [IFLA_CAN_BITTIMING_CONST]
 812                                 = { .len = sizeof(struct can_bittiming_const) },
 813         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 814         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 815         [IFLA_CAN_DATA_BITTIMING]
 816                                 = { .len = sizeof(struct can_bittiming) },
 817         [IFLA_CAN_DATA_BITTIMING_CONST]
 818                                 = { .len = sizeof(struct can_bittiming_const) },
 819 };
 820
 821 static int can_validate(struct nlattr *tb[], struct nlattr *data[])
 822 {
 823         bool is_can_fd = false;
 824
 825         /* Make sure that valid CAN FD configurations always consist of
 826          * - nominal/arbitration bittiming
 827          * - data bittiming
 828          * - control mode with CAN_CTRLMODE_FD set
 829          */
 830
 831         if (!data)
 832                 return 0;
 833
 834         if (data[IFLA_CAN_CTRLMODE]) {
 835                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 836
 837                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 838         }
 839
 840         if (is_can_fd) {
 841                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 842                         return -EOPNOTSUPP;
 843         }
 844
 845         if (data[IFLA_CAN_DATA_BITTIMING]) {
 846                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 847                         return -EOPNOTSUPP;
 848         }
 849
 850         return 0;
 851 }
 852
 853 static int can_changelink(struct net_device *dev,
 854                           struct nlattr *tb[], struct nlattr *data[])
 855 {
 856         struct can_priv *priv = netdev_priv(dev);
 857         int err;
 858
 859         /* We need synchronization with dev->stop() */
 860         ASSERT_RTNL();
 861
 862         if (data[IFLA_CAN_BITTIMING]) {
 863                 struct can_bittiming bt;
 864
 865                 /* Do not allow changing bittiming while running */
 866                 if (dev->flags & IFF_UP)
 867                         return -EBUSY;
 868                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 869                 err = can_get_bittiming(dev, &bt, priv->bittiming_const);
 870                 if (err)
 871                         return err;
 872                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 873
 874                 if (priv->do_set_bittiming) {
 875                         /* Finally, set the bit-timing registers */
 876                         err = priv->do_set_bittiming(dev);
 877                         if (err)
 878                                 return err;
 879                 }
 880         }
 881
 882         if (data[IFLA_CAN_CTRLMODE]) {
 883                 struct can_ctrlmode *cm;
 884                 u32 ctrlstatic;
 885                 u32 maskedflags;
 886
 887                 /* Do not allow changing controller mode while running */
 888                 if (dev->flags & IFF_UP)
 889                         return -EBUSY;
 890                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 891                 ctrlstatic = priv->ctrlmode_static;
 892                 maskedflags = cm->flags & cm->mask;
 893
 894                 /* check whether provided bits are allowed to be passed */
 895                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
 896                         return -EOPNOTSUPP;
 897
 898                 /* do not check for static fd-non-iso if 'fd' is disabled */
 899                 if (!(maskedflags & CAN_CTRLMODE_FD))
 900                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
 901
 902                 /* make sure static options are provided by configuration */
 903                 if ((maskedflags & ctrlstatic) != ctrlstatic)
 904                         return -EOPNOTSUPP;
 905
 906                 /* clear bits to be modified and copy the flag values */
 907                 priv->ctrlmode &= ~cm->mask;
 908                 priv->ctrlmode |= maskedflags;
 909
 910                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
 911                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
 912                         dev->mtu = CANFD_MTU;
 913                 else
 914                         dev->mtu = CAN_MTU;
 915         }
 916
 917         if (data[IFLA_CAN_RESTART_MS]) {
 918                 /* Do not allow changing restart delay while running */
 919                 if (dev->flags & IFF_UP)
 920                         return -EBUSY;
 921                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
 922         }
 923
 924         if (data[IFLA_CAN_RESTART]) {
 925                 /* Do not allow a restart while not running */
 926                 if (!(dev->flags & IFF_UP))
 927                         return -EINVAL;
 928                 err = can_restart_now(dev);
 929                 if (err)
 930                         return err;
 931         }
 932
 933         if (data[IFLA_CAN_DATA_BITTIMING]) {
 934                 struct can_bittiming dbt;
 935
 936                 /* Do not allow changing bittiming while running */
 937                 if (dev->flags & IFF_UP)
 938                         return -EBUSY;
 939                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
 940                        sizeof(dbt));
 941                 err = can_get_bittiming(dev, &dbt, priv->data_bittiming_const);
 942                 if (err)
 943                         return err;
 944                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
 945
 946                 if (priv->do_set_data_bittiming) {
 947                         /* Finally, set the bit-timing registers */
 948                         err = priv->do_set_data_bittiming(dev);
 949                         if (err)
 950                                 return err;
 951                 }
 952         }
 953
 954         return 0;
 955 }
 956
 957 static size_t can_get_size(const struct net_device *dev)
 958 {
 959         struct can_priv *priv = netdev_priv(dev);
 960         size_t size = 0;
 961
 962         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
 963                 size += nla_total_size(sizeof(struct can_bittiming));
 964         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
 965                 size += nla_total_size(sizeof(struct can_bittiming_const));
 966         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
 967         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
 968         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
 969         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
 970         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
 971                 size += nla_total_size(sizeof(struct can_berr_counter));
 972         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
 973                 size += nla_total_size(sizeof(struct can_bittiming));
 974         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
 975                 size += nla_total_size(sizeof(struct can_bittiming_const));
 976
 977         return size;
 978 }
 979
 980 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 981 {
 982         struct can_priv *priv = netdev_priv(dev);
 983         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
 984         struct can_berr_counter bec;
 985         enum can_state state = priv->state;
 986
 987         if (priv->do_get_state)
 988                 priv->do_get_state(dev, &state);
 989
 990         if ((priv->bittiming.bitrate &&
 991              nla_put(skb, IFLA_CAN_BITTIMING,
 992                      sizeof(priv->bittiming), &priv->bittiming)) ||
 993
 994             (priv->bittiming_const &&
 995              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
 996                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
 997
 998             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
 999             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1000             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1001             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1002
1003             (priv->do_get_berr_counter &&
1004              !priv->do_get_berr_counter(dev, &bec) &&
1005              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1006
1007             (priv->data_bittiming.bitrate &&
1008              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1009                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1010
1011             (priv->data_bittiming_const &&
1012              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1013                      sizeof(*priv->data_bittiming_const),
1014                      priv->data_bittiming_const)))
1015                 return -EMSGSIZE;
1016
1017         return 0;
1018 }
1019
1020 static size_t can_get_xstats_size(const struct net_device *dev)
1021 {
1022         return sizeof(struct can_device_stats);
1023 }
1024
1025 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1026 {
1027         struct can_priv *priv = netdev_priv(dev);
1028
1029         if (nla_put(skb, IFLA_INFO_XSTATS,
1030                     sizeof(priv->can_stats), &priv->can_stats))
1031                 goto nla_put_failure;
1032         return 0;
1033
1034 nla_put_failure:
1035         return -EMSGSIZE;
1036 }
1037
1038 static int can_newlink(struct net *src_net, struct net_device *dev,
1039                        struct nlattr *tb[], struct nlattr *data[])
1040 {
1041         return -EOPNOTSUPP;
1042 }
1043
1044 static void can_dellink(struct net_device *dev, struct list_head *head)
1045 {
1046         return;
1047 }
1048
1049 static struct rtnl_link_ops can_link_ops __read_mostly = {
1050         .kind           = "can",
1051         .maxtype        = IFLA_CAN_MAX,
1052         .policy         = can_policy,
1053         .setup          = can_setup,
1054         .validate       = can_validate,
1055         .newlink        = can_newlink,
1056         .changelink     = can_changelink,
1057         .dellink        = can_dellink,
1058         .get_size       = can_get_size,
1059         .fill_info      = can_fill_info,
1060         .get_xstats_size = can_get_xstats_size,
1061         .fill_xstats    = can_fill_xstats,
1062 };
1063
1064 /*
1065  * Register the CAN network device
1066  */
1067 int register_candev(struct net_device *dev)
1068 {
1069         dev->rtnl_link_ops = &can_link_ops;
1070         return register_netdev(dev);
1071 }
1072 EXPORT_SYMBOL_GPL(register_candev);
1073
1074 /*
1075  * Unregister the CAN network device
1076  */
1077 void unregister_candev(struct net_device *dev)
1078 {
1079         unregister_netdev(dev);
1080 }
1081 EXPORT_SYMBOL_GPL(unregister_candev);
1082
1083 /*
1084  * Test if a network device is a candev based device
1085  * and return the can_priv* if so.
1086  */
1087 struct can_priv *safe_candev_priv(struct net_device *dev)
1088 {
1089         if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1090                 return NULL;
1091
1092         return netdev_priv(dev);
1093 }
1094 EXPORT_SYMBOL_GPL(safe_candev_priv);
1095
1096 static __init int can_dev_init(void)
1097 {
1098         int err;
1099
1100         can_led_notifier_init();
1101
1102         err = rtnl_link_register(&can_link_ops);
1103         if (!err)
1104                 printk(KERN_INFO MOD_DESC "\n");
1105
1106         return err;
1107 }
1108 module_init(can_dev_init);
1109
1110 static __exit void can_dev_exit(void)
1111 {
1112         rtnl_link_unregister(&can_link_ops);
1113
1114         can_led_notifier_exit();
1115 }
1116 module_exit(can_dev_exit);
1117
1118 MODULE_ALIAS_RTNL_LINK("can");