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 #define CAN_CALC_SYNC_SEG 1
  74
  75 /*
  76  * Bit-timing calculation derived from:
  77  *
  78  * Code based on LinCAN sources and H8S2638 project
  79  * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
  80  * Copyright 2005      Stanislav Marek
  81  * email: pisa@cmp.felk.cvut.cz
  82  *
  83  * Calculates proper bit-timing parameters for a specified bit-rate
  84  * and sample-point, which can then be used to set the bit-timing
  85  * registers of the CAN controller. You can find more information
  86  * in the header file linux/can/netlink.h.
  87  */
  88 static int can_update_sample_point(const struct can_bittiming_const *btc,
  89                           unsigned int sample_point_nominal, unsigned int tseg,
  90                           unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
  91                           unsigned int *sample_point_error_ptr)
  92 {
  93         unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
  94         unsigned int sample_point, best_sample_point = 0;
  95         unsigned int tseg1, tseg2;
  96         int i;
  97
  98         for (i = 0; i <= 1; i++) {
  99                 tseg2 = tseg + CAN_CALC_SYNC_SEG - (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) / 1000 - i;
 100                 tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
 101                 tseg1 = tseg - tseg2;
 102                 if (tseg1 > btc->tseg1_max) {
 103                         tseg1 = btc->tseg1_max;
 104                         tseg2 = tseg - tseg1;
 105                 }
 106
 107                 sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) / (tseg + CAN_CALC_SYNC_SEG);
 108                 sample_point_error = abs(sample_point_nominal - sample_point);
 109
 110                 if ((sample_point <= sample_point_nominal) && (sample_point_error < best_sample_point_error)) {
 111                         best_sample_point = sample_point;
 112                         best_sample_point_error = sample_point_error;
 113                         *tseg1_ptr = tseg1;
 114                         *tseg2_ptr = tseg2;
 115                 }
 116         }
 117
 118         if (sample_point_error_ptr)
 119                 *sample_point_error_ptr = best_sample_point_error;
 120
 121         return best_sample_point;
 122 }
 123
 124 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 125                               const struct can_bittiming_const *btc)
 126 {
 127         struct can_priv *priv = netdev_priv(dev);
 128         unsigned int bitrate;                   /* current bitrate */
 129         unsigned int bitrate_error;             /* difference between current and nominal value */
 130         unsigned int best_bitrate_error = UINT_MAX;
 131         unsigned int sample_point_error;        /* difference between current and nominal value */
 132         unsigned int best_sample_point_error = UINT_MAX;
 133         unsigned int sample_point_nominal;      /* nominal sample point */
 134         unsigned int best_tseg = 0;             /* current best value for tseg */
 135         unsigned int best_brp = 0;              /* current best value for brp */
 136         unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
 137         u64 v64;
 138
 139         /* Use CiA recommended sample points */
 140         if (bt->sample_point) {
 141                 sample_point_nominal = bt->sample_point;
 142         } else {
 143                 if (bt->bitrate > 800000)
 144                         sample_point_nominal = 750;
 145                 else if (bt->bitrate > 500000)
 146                         sample_point_nominal = 800;
 147                 else
 148                         sample_point_nominal = 875;
 149         }
 150
 151         /* tseg even = round down, odd = round up */
 152         for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
 153              tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
 154                 tsegall = CAN_CALC_SYNC_SEG + tseg / 2;
 155
 156                 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
 157                 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
 158
 159                 /* choose brp step which is possible in system */
 160                 brp = (brp / btc->brp_inc) * btc->brp_inc;
 161                 if ((brp < btc->brp_min) || (brp > btc->brp_max))
 162                         continue;
 163
 164                 bitrate = priv->clock.freq / (brp * tsegall);
 165                 bitrate_error = abs(bt->bitrate - bitrate);
 166
 167                 /* tseg brp biterror */
 168                 if (bitrate_error > best_bitrate_error)
 169                         continue;
 170
 171                 /* reset sample point error if we have a better bitrate */
 172                 if (bitrate_error < best_bitrate_error)
 173                         best_sample_point_error = UINT_MAX;
 174
 175                 can_update_sample_point(btc, sample_point_nominal, tseg / 2, &tseg1, &tseg2, &sample_point_error);
 176                 if (sample_point_error > best_sample_point_error)
 177                         continue;
 178
 179                 best_sample_point_error = sample_point_error;
 180                 best_bitrate_error = bitrate_error;
 181                 best_tseg = tseg / 2;
 182                 best_brp = brp;
 183
 184                 if (bitrate_error == 0 && sample_point_error == 0)
 185                         break;
 186         }
 187
 188         if (best_bitrate_error) {
 189                 /* Error in one-tenth of a percent */
 190                 v64 = (u64)best_bitrate_error * 1000;
 191                 do_div(v64, bt->bitrate);
 192                 bitrate_error = (u32)v64;
 193                 if (bitrate_error > CAN_CALC_MAX_ERROR) {
 194                         netdev_err(dev,
 195                                    "bitrate error %d.%d%% too high\n",
 196                                    bitrate_error / 10, bitrate_error % 10);
 197                         return -EDOM;
 198                 }
 199                 netdev_warn(dev, "bitrate error %d.%d%%\n",
 200                             bitrate_error / 10, bitrate_error % 10);
 201         }
 202
 203         /* real sample point */
 204         bt->sample_point = can_update_sample_point(btc, sample_point_nominal, best_tseg,
 205                                           &tseg1, &tseg2, NULL);
 206
 207         v64 = (u64)best_brp * 1000 * 1000 * 1000;
 208         do_div(v64, priv->clock.freq);
 209         bt->tq = (u32)v64;
 210         bt->prop_seg = tseg1 / 2;
 211         bt->phase_seg1 = tseg1 - bt->prop_seg;
 212         bt->phase_seg2 = tseg2;
 213
 214         /* check for sjw user settings */
 215         if (!bt->sjw || !btc->sjw_max) {
 216                 bt->sjw = 1;
 217         } else {
 218                 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
 219                 if (bt->sjw > btc->sjw_max)
 220                         bt->sjw = btc->sjw_max;
 221                 /* bt->sjw must not be higher than tseg2 */
 222                 if (tseg2 < bt->sjw)
 223                         bt->sjw = tseg2;
 224         }
 225
 226         bt->brp = best_brp;
 227
 228         /* real bitrate */
 229         bt->bitrate = priv->clock.freq / (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2));
 230
 231         return 0;
 232 }
 233 #else /* !CONFIG_CAN_CALC_BITTIMING */
 234 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
 235                               const struct can_bittiming_const *btc)
 236 {
 237         netdev_err(dev, "bit-timing calculation not available\n");
 238         return -EINVAL;
 239 }
 240 #endif /* CONFIG_CAN_CALC_BITTIMING */
 241
 242 /*
 243  * Checks the validity of the specified bit-timing parameters prop_seg,
 244  * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
 245  * prescaler value brp. You can find more information in the header
 246  * file linux/can/netlink.h.
 247  */
 248 static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
 249                                const struct can_bittiming_const *btc)
 250 {
 251         struct can_priv *priv = netdev_priv(dev);
 252         int tseg1, alltseg;
 253         u64 brp64;
 254
 255         tseg1 = bt->prop_seg + bt->phase_seg1;
 256         if (!bt->sjw)
 257                 bt->sjw = 1;
 258         if (bt->sjw > btc->sjw_max ||
 259             tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
 260             bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
 261                 return -ERANGE;
 262
 263         brp64 = (u64)priv->clock.freq * (u64)bt->tq;
 264         if (btc->brp_inc > 1)
 265                 do_div(brp64, btc->brp_inc);
 266         brp64 += 500000000UL - 1;
 267         do_div(brp64, 1000000000UL); /* the practicable BRP */
 268         if (btc->brp_inc > 1)
 269                 brp64 *= btc->brp_inc;
 270         bt->brp = (u32)brp64;
 271
 272         if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
 273                 return -EINVAL;
 274
 275         alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
 276         bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
 277         bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
 278
 279         return 0;
 280 }
 281
 282 static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
 283                              const struct can_bittiming_const *btc)
 284 {
 285         int err;
 286
 287         /* Check if the CAN device has bit-timing parameters */
 288         if (!btc)
 289                 return -EOPNOTSUPP;
 290
 291         /*
 292          * Depending on the given can_bittiming parameter structure the CAN
 293          * timing parameters are calculated based on the provided bitrate OR
 294          * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
 295          * provided directly which are then checked and fixed up.
 296          */
 297         if (!bt->tq && bt->bitrate)
 298                 err = can_calc_bittiming(dev, bt, btc);
 299         else if (bt->tq && !bt->bitrate)
 300                 err = can_fixup_bittiming(dev, bt, btc);
 301         else
 302                 err = -EINVAL;
 303
 304         return err;
 305 }
 306
 307 static void can_update_state_error_stats(struct net_device *dev,
 308                                          enum can_state new_state)
 309 {
 310         struct can_priv *priv = netdev_priv(dev);
 311
 312         if (new_state <= priv->state)
 313                 return;
 314
 315         switch (new_state) {
 316         case CAN_STATE_ERROR_WARNING:
 317                 priv->can_stats.error_warning++;
 318                 break;
 319         case CAN_STATE_ERROR_PASSIVE:
 320                 priv->can_stats.error_passive++;
 321                 break;
 322         case CAN_STATE_BUS_OFF:
 323                 priv->can_stats.bus_off++;
 324                 break;
 325         default:
 326                 break;
 327         }
 328 }
 329
 330 static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
 331 {
 332         switch (state) {
 333         case CAN_STATE_ERROR_ACTIVE:
 334                 return CAN_ERR_CRTL_ACTIVE;
 335         case CAN_STATE_ERROR_WARNING:
 336                 return CAN_ERR_CRTL_TX_WARNING;
 337         case CAN_STATE_ERROR_PASSIVE:
 338                 return CAN_ERR_CRTL_TX_PASSIVE;
 339         default:
 340                 return 0;
 341         }
 342 }
 343
 344 static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
 345 {
 346         switch (state) {
 347         case CAN_STATE_ERROR_ACTIVE:
 348                 return CAN_ERR_CRTL_ACTIVE;
 349         case CAN_STATE_ERROR_WARNING:
 350                 return CAN_ERR_CRTL_RX_WARNING;
 351         case CAN_STATE_ERROR_PASSIVE:
 352                 return CAN_ERR_CRTL_RX_PASSIVE;
 353         default:
 354                 return 0;
 355         }
 356 }
 357
 358 void can_change_state(struct net_device *dev, struct can_frame *cf,
 359                       enum can_state tx_state, enum can_state rx_state)
 360 {
 361         struct can_priv *priv = netdev_priv(dev);
 362         enum can_state new_state = max(tx_state, rx_state);
 363
 364         if (unlikely(new_state == priv->state)) {
 365                 netdev_warn(dev, "%s: oops, state did not change", __func__);
 366                 return;
 367         }
 368
 369         netdev_dbg(dev, "New error state: %d\n", new_state);
 370
 371         can_update_state_error_stats(dev, new_state);
 372         priv->state = new_state;
 373
 374         if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
 375                 cf->can_id |= CAN_ERR_BUSOFF;
 376                 return;
 377         }
 378
 379         cf->can_id |= CAN_ERR_CRTL;
 380         cf->data[1] |= tx_state >= rx_state ?
 381                        can_tx_state_to_frame(dev, tx_state) : 0;
 382         cf->data[1] |= tx_state <= rx_state ?
 383                        can_rx_state_to_frame(dev, rx_state) : 0;
 384 }
 385 EXPORT_SYMBOL_GPL(can_change_state);
 386
 387 /*
 388  * Local echo of CAN messages
 389  *
 390  * CAN network devices *should* support a local echo functionality
 391  * (see Documentation/networking/can.txt). To test the handling of CAN
 392  * interfaces that do not support the local echo both driver types are
 393  * implemented. In the case that the driver does not support the echo
 394  * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
 395  * to perform the echo as a fallback solution.
 396  */
 397 static void can_flush_echo_skb(struct net_device *dev)
 398 {
 399         struct can_priv *priv = netdev_priv(dev);
 400         struct net_device_stats *stats = &dev->stats;
 401         int i;
 402
 403         for (i = 0; i < priv->echo_skb_max; i++) {
 404                 if (priv->echo_skb[i]) {
 405                         kfree_skb(priv->echo_skb[i]);
 406                         priv->echo_skb[i] = NULL;
 407                         stats->tx_dropped++;
 408                         stats->tx_aborted_errors++;
 409                 }
 410         }
 411 }
 412
 413 /*
 414  * Put the skb on the stack to be looped backed locally lateron
 415  *
 416  * The function is typically called in the start_xmit function
 417  * of the device driver. The driver must protect access to
 418  * priv->echo_skb, if necessary.
 419  */
 420 void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 421                       unsigned int idx)
 422 {
 423         struct can_priv *priv = netdev_priv(dev);
 424
 425         BUG_ON(idx >= priv->echo_skb_max);
 426
 427         /* check flag whether this packet has to be looped back */
 428         if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
 429             (skb->protocol != htons(ETH_P_CAN) &&
 430              skb->protocol != htons(ETH_P_CANFD))) {
 431                 kfree_skb(skb);
 432                 return;
 433         }
 434
 435         if (!priv->echo_skb[idx]) {
 436
 437                 skb = can_create_echo_skb(skb);
 438                 if (!skb)
 439                         return;
 440
 441                 /* make settings for echo to reduce code in irq context */
 442                 skb->pkt_type = PACKET_BROADCAST;
 443                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 444                 skb->dev = dev;
 445
 446                 /* save this skb for tx interrupt echo handling */
 447                 priv->echo_skb[idx] = skb;
 448         } else {
 449                 /* locking problem with netif_stop_queue() ?? */
 450                 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
 451                 kfree_skb(skb);
 452         }
 453 }
 454 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 455
 456 /*
 457  * Get the skb from the stack and loop it back locally
 458  *
 459  * The function is typically called when the TX done interrupt
 460  * is handled in the device driver. The driver must protect
 461  * access to priv->echo_skb, if necessary.
 462  */
 463 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 464 {
 465         struct can_priv *priv = netdev_priv(dev);
 466
 467         BUG_ON(idx >= priv->echo_skb_max);
 468
 469         if (priv->echo_skb[idx]) {
 470                 struct sk_buff *skb = priv->echo_skb[idx];
 471                 struct can_frame *cf = (struct can_frame *)skb->data;
 472                 u8 dlc = cf->can_dlc;
 473
 474                 netif_rx(priv->echo_skb[idx]);
 475                 priv->echo_skb[idx] = NULL;
 476
 477                 return dlc;
 478         }
 479
 480         return 0;
 481 }
 482 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 483
 484 /*
 485   * Remove the skb from the stack and free it.
 486   *
 487   * The function is typically called when TX failed.
 488   */
 489 void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 490 {
 491         struct can_priv *priv = netdev_priv(dev);
 492
 493         BUG_ON(idx >= priv->echo_skb_max);
 494
 495         if (priv->echo_skb[idx]) {
 496                 dev_kfree_skb_any(priv->echo_skb[idx]);
 497                 priv->echo_skb[idx] = NULL;
 498         }
 499 }
 500 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 501
 502 /*
 503  * CAN device restart for bus-off recovery
 504  */
 505 static void can_restart(struct net_device *dev)
 506 {
 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 static void can_restart_work(struct work_struct *work)
 547 {
 548         struct delayed_work *dwork = to_delayed_work(work);
 549         struct can_priv *priv = container_of(dwork, struct can_priv, restart_work);
 550
 551         can_restart(priv->dev);
 552 }
 553
 554 int can_restart_now(struct net_device *dev)
 555 {
 556         struct can_priv *priv = netdev_priv(dev);
 557
 558         /*
 559          * A manual restart is only permitted if automatic restart is
 560          * disabled and the device is in the bus-off state
 561          */
 562         if (priv->restart_ms)
 563                 return -EINVAL;
 564         if (priv->state != CAN_STATE_BUS_OFF)
 565                 return -EBUSY;
 566
 567         cancel_delayed_work_sync(&priv->restart_work);
 568         can_restart(dev);
 569
 570         return 0;
 571 }
 572
 573 /*
 574  * CAN bus-off
 575  *
 576  * This functions should be called when the device goes bus-off to
 577  * tell the netif layer that no more packets can be sent or received.
 578  * If enabled, a timer is started to trigger bus-off recovery.
 579  */
 580 void can_bus_off(struct net_device *dev)
 581 {
 582         struct can_priv *priv = netdev_priv(dev);
 583
 584         netdev_dbg(dev, "bus-off\n");
 585
 586         netif_carrier_off(dev);
 587
 588         if (priv->restart_ms)
 589                 schedule_delayed_work(&priv->restart_work,
 590                                       msecs_to_jiffies(priv->restart_ms));
 591 }
 592 EXPORT_SYMBOL_GPL(can_bus_off);
 593
 594 static void can_setup(struct net_device *dev)
 595 {
 596         dev->type = ARPHRD_CAN;
 597         dev->mtu = CAN_MTU;
 598         dev->hard_header_len = 0;
 599         dev->addr_len = 0;
 600         dev->tx_queue_len = 10;
 601
 602         /* New-style flags. */
 603         dev->flags = IFF_NOARP;
 604         dev->features = NETIF_F_HW_CSUM;
 605 }
 606
 607 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 608 {
 609         struct sk_buff *skb;
 610
 611         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 612                                sizeof(struct can_frame));
 613         if (unlikely(!skb))
 614                 return NULL;
 615
 616         skb->protocol = htons(ETH_P_CAN);
 617         skb->pkt_type = PACKET_BROADCAST;
 618         skb->ip_summed = CHECKSUM_UNNECESSARY;
 619
 620         skb_reset_mac_header(skb);
 621         skb_reset_network_header(skb);
 622         skb_reset_transport_header(skb);
 623
 624         can_skb_reserve(skb);
 625         can_skb_prv(skb)->ifindex = dev->ifindex;
 626         can_skb_prv(skb)->skbcnt = 0;
 627
 628         *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
 629         memset(*cf, 0, sizeof(struct can_frame));
 630
 631         return skb;
 632 }
 633 EXPORT_SYMBOL_GPL(alloc_can_skb);
 634
 635 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 636                                 struct canfd_frame **cfd)
 637 {
 638         struct sk_buff *skb;
 639
 640         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 641                                sizeof(struct canfd_frame));
 642         if (unlikely(!skb))
 643                 return NULL;
 644
 645         skb->protocol = htons(ETH_P_CANFD);
 646         skb->pkt_type = PACKET_BROADCAST;
 647         skb->ip_summed = CHECKSUM_UNNECESSARY;
 648
 649         skb_reset_mac_header(skb);
 650         skb_reset_network_header(skb);
 651         skb_reset_transport_header(skb);
 652
 653         can_skb_reserve(skb);
 654         can_skb_prv(skb)->ifindex = dev->ifindex;
 655         can_skb_prv(skb)->skbcnt = 0;
 656
 657         *cfd = (struct canfd_frame *)skb_put(skb, sizeof(struct canfd_frame));
 658         memset(*cfd, 0, sizeof(struct canfd_frame));
 659
 660         return skb;
 661 }
 662 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 663
 664 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 665 {
 666         struct sk_buff *skb;
 667
 668         skb = alloc_can_skb(dev, cf);
 669         if (unlikely(!skb))
 670                 return NULL;
 671
 672         (*cf)->can_id = CAN_ERR_FLAG;
 673         (*cf)->can_dlc = CAN_ERR_DLC;
 674
 675         return skb;
 676 }
 677 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 678
 679 /*
 680  * Allocate and setup space for the CAN network device
 681  */
 682 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
 683 {
 684         struct net_device *dev;
 685         struct can_priv *priv;
 686         int size;
 687
 688         if (echo_skb_max)
 689                 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
 690                         echo_skb_max * sizeof(struct sk_buff *);
 691         else
 692                 size = sizeof_priv;
 693
 694         dev = alloc_netdev(size, "can%d", NET_NAME_UNKNOWN, can_setup);
 695         if (!dev)
 696                 return NULL;
 697
 698         priv = netdev_priv(dev);
 699         priv->dev = dev;
 700
 701         if (echo_skb_max) {
 702                 priv->echo_skb_max = echo_skb_max;
 703                 priv->echo_skb = (void *)priv +
 704                         ALIGN(sizeof_priv, sizeof(struct sk_buff *));
 705         }
 706
 707         priv->state = CAN_STATE_STOPPED;
 708
 709         INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
 710
 711         return dev;
 712 }
 713 EXPORT_SYMBOL_GPL(alloc_candev);
 714
 715 /*
 716  * Free space of the CAN network device
 717  */
 718 void free_candev(struct net_device *dev)
 719 {
 720         free_netdev(dev);
 721 }
 722 EXPORT_SYMBOL_GPL(free_candev);
 723
 724 /*
 725  * changing MTU and control mode for CAN/CANFD devices
 726  */
 727 int can_change_mtu(struct net_device *dev, int new_mtu)
 728 {
 729         struct can_priv *priv = netdev_priv(dev);
 730
 731         /* Do not allow changing the MTU while running */
 732         if (dev->flags & IFF_UP)
 733                 return -EBUSY;
 734
 735         /* allow change of MTU according to the CANFD ability of the device */
 736         switch (new_mtu) {
 737         case CAN_MTU:
 738                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 739                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 740                         return -EINVAL;
 741
 742                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 743                 break;
 744
 745         case CANFD_MTU:
 746                 /* check for potential CANFD ability */
 747                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 748                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 749                         return -EINVAL;
 750
 751                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 752                 break;
 753
 754         default:
 755                 return -EINVAL;
 756         }
 757
 758         dev->mtu = new_mtu;
 759         return 0;
 760 }
 761 EXPORT_SYMBOL_GPL(can_change_mtu);
 762
 763 /*
 764  * Common open function when the device gets opened.
 765  *
 766  * This function should be called in the open function of the device
 767  * driver.
 768  */
 769 int open_candev(struct net_device *dev)
 770 {
 771         struct can_priv *priv = netdev_priv(dev);
 772
 773         if (!priv->bittiming.bitrate) {
 774                 netdev_err(dev, "bit-timing not yet defined\n");
 775                 return -EINVAL;
 776         }
 777
 778         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 779         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 780             (!priv->data_bittiming.bitrate ||
 781              (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
 782                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 783                 return -EINVAL;
 784         }
 785
 786         /* Switch carrier on if device was stopped while in bus-off state */
 787         if (!netif_carrier_ok(dev))
 788                 netif_carrier_on(dev);
 789
 790         return 0;
 791 }
 792 EXPORT_SYMBOL_GPL(open_candev);
 793
 794 /*
 795  * Common close function for cleanup before the device gets closed.
 796  *
 797  * This function should be called in the close function of the device
 798  * driver.
 799  */
 800 void close_candev(struct net_device *dev)
 801 {
 802         struct can_priv *priv = netdev_priv(dev);
 803
 804         cancel_delayed_work_sync(&priv->restart_work);
 805         can_flush_echo_skb(dev);
 806 }
 807 EXPORT_SYMBOL_GPL(close_candev);
 808
 809 /*
 810  * CAN netlink interface
 811  */
 812 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 813         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 814         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 815         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 816         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 817         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 818         [IFLA_CAN_BITTIMING_CONST]
 819                                 = { .len = sizeof(struct can_bittiming_const) },
 820         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 821         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 822         [IFLA_CAN_DATA_BITTIMING]
 823                                 = { .len = sizeof(struct can_bittiming) },
 824         [IFLA_CAN_DATA_BITTIMING_CONST]
 825                                 = { .len = sizeof(struct can_bittiming_const) },
 826 };
 827
 828 static int can_validate(struct nlattr *tb[], struct nlattr *data[])
 829 {
 830         bool is_can_fd = false;
 831
 832         /* Make sure that valid CAN FD configurations always consist of
 833          * - nominal/arbitration bittiming
 834          * - data bittiming
 835          * - control mode with CAN_CTRLMODE_FD set
 836          */
 837
 838         if (!data)
 839                 return 0;
 840
 841         if (data[IFLA_CAN_CTRLMODE]) {
 842                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 843
 844                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 845         }
 846
 847         if (is_can_fd) {
 848                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 849                         return -EOPNOTSUPP;
 850         }
 851
 852         if (data[IFLA_CAN_DATA_BITTIMING]) {
 853                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 854                         return -EOPNOTSUPP;
 855         }
 856
 857         return 0;
 858 }
 859
 860 static int can_changelink(struct net_device *dev,
 861                           struct nlattr *tb[], struct nlattr *data[])
 862 {
 863         struct can_priv *priv = netdev_priv(dev);
 864         int err;
 865
 866         /* We need synchronization with dev->stop() */
 867         ASSERT_RTNL();
 868
 869         if (data[IFLA_CAN_BITTIMING]) {
 870                 struct can_bittiming bt;
 871
 872                 /* Do not allow changing bittiming while running */
 873                 if (dev->flags & IFF_UP)
 874                         return -EBUSY;
 875                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 876                 err = can_get_bittiming(dev, &bt, priv->bittiming_const);
 877                 if (err)
 878                         return err;
 879                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 880
 881                 if (priv->do_set_bittiming) {
 882                         /* Finally, set the bit-timing registers */
 883                         err = priv->do_set_bittiming(dev);
 884                         if (err)
 885                                 return err;
 886                 }
 887         }
 888
 889         if (data[IFLA_CAN_CTRLMODE]) {
 890                 struct can_ctrlmode *cm;
 891                 u32 ctrlstatic;
 892                 u32 maskedflags;
 893
 894                 /* Do not allow changing controller mode while running */
 895                 if (dev->flags & IFF_UP)
 896                         return -EBUSY;
 897                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 898                 ctrlstatic = priv->ctrlmode_static;
 899                 maskedflags = cm->flags & cm->mask;
 900
 901                 /* check whether provided bits are allowed to be passed */
 902                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
 903                         return -EOPNOTSUPP;
 904
 905                 /* do not check for static fd-non-iso if 'fd' is disabled */
 906                 if (!(maskedflags & CAN_CTRLMODE_FD))
 907                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
 908
 909                 /* make sure static options are provided by configuration */
 910                 if ((maskedflags & ctrlstatic) != ctrlstatic)
 911                         return -EOPNOTSUPP;
 912
 913                 /* clear bits to be modified and copy the flag values */
 914                 priv->ctrlmode &= ~cm->mask;
 915                 priv->ctrlmode |= maskedflags;
 916
 917                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
 918                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
 919                         dev->mtu = CANFD_MTU;
 920                 else
 921                         dev->mtu = CAN_MTU;
 922         }
 923
 924         if (data[IFLA_CAN_RESTART_MS]) {
 925                 /* Do not allow changing restart delay while running */
 926                 if (dev->flags & IFF_UP)
 927                         return -EBUSY;
 928                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
 929         }
 930
 931         if (data[IFLA_CAN_RESTART]) {
 932                 /* Do not allow a restart while not running */
 933                 if (!(dev->flags & IFF_UP))
 934                         return -EINVAL;
 935                 err = can_restart_now(dev);
 936                 if (err)
 937                         return err;
 938         }
 939
 940         if (data[IFLA_CAN_DATA_BITTIMING]) {
 941                 struct can_bittiming dbt;
 942
 943                 /* Do not allow changing bittiming while running */
 944                 if (dev->flags & IFF_UP)
 945                         return -EBUSY;
 946                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
 947                        sizeof(dbt));
 948                 err = can_get_bittiming(dev, &dbt, priv->data_bittiming_const);
 949                 if (err)
 950                         return err;
 951                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
 952
 953                 if (priv->do_set_data_bittiming) {
 954                         /* Finally, set the bit-timing registers */
 955                         err = priv->do_set_data_bittiming(dev);
 956                         if (err)
 957                                 return err;
 958                 }
 959         }
 960
 961         return 0;
 962 }
 963
 964 static size_t can_get_size(const struct net_device *dev)
 965 {
 966         struct can_priv *priv = netdev_priv(dev);
 967         size_t size = 0;
 968
 969         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
 970                 size += nla_total_size(sizeof(struct can_bittiming));
 971         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
 972                 size += nla_total_size(sizeof(struct can_bittiming_const));
 973         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
 974         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
 975         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
 976         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
 977         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
 978                 size += nla_total_size(sizeof(struct can_berr_counter));
 979         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
 980                 size += nla_total_size(sizeof(struct can_bittiming));
 981         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
 982                 size += nla_total_size(sizeof(struct can_bittiming_const));
 983
 984         return size;
 985 }
 986
 987 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 988 {
 989         struct can_priv *priv = netdev_priv(dev);
 990         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
 991         struct can_berr_counter bec;
 992         enum can_state state = priv->state;
 993
 994         if (priv->do_get_state)
 995                 priv->do_get_state(dev, &state);
 996
 997         if ((priv->bittiming.bitrate &&
 998              nla_put(skb, IFLA_CAN_BITTIMING,
 999                      sizeof(priv->bittiming), &priv->bittiming)) ||
1000
1001             (priv->bittiming_const &&
1002              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1003                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1004
1005             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1006             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1007             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1008             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1009
1010             (priv->do_get_berr_counter &&
1011              !priv->do_get_berr_counter(dev, &bec) &&
1012              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1013
1014             (priv->data_bittiming.bitrate &&
1015              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1016                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1017
1018             (priv->data_bittiming_const &&
1019              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1020                      sizeof(*priv->data_bittiming_const),
1021                      priv->data_bittiming_const)))
1022                 return -EMSGSIZE;
1023
1024         return 0;
1025 }
1026
1027 static size_t can_get_xstats_size(const struct net_device *dev)
1028 {
1029         return sizeof(struct can_device_stats);
1030 }
1031
1032 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1033 {
1034         struct can_priv *priv = netdev_priv(dev);
1035
1036         if (nla_put(skb, IFLA_INFO_XSTATS,
1037                     sizeof(priv->can_stats), &priv->can_stats))
1038                 goto nla_put_failure;
1039         return 0;
1040
1041 nla_put_failure:
1042         return -EMSGSIZE;
1043 }
1044
1045 static int can_newlink(struct net *src_net, struct net_device *dev,
1046                        struct nlattr *tb[], struct nlattr *data[])
1047 {
1048         return -EOPNOTSUPP;
1049 }
1050
1051 static void can_dellink(struct net_device *dev, struct list_head *head)
1052 {
1053         return;
1054 }
1055
1056 static struct rtnl_link_ops can_link_ops __read_mostly = {
1057         .kind           = "can",
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         return register_netdev(dev);
1078 }
1079 EXPORT_SYMBOL_GPL(register_candev);
1080
1081 /*
1082  * Unregister the CAN network device
1083  */
1084 void unregister_candev(struct net_device *dev)
1085 {
1086         unregister_netdev(dev);
1087 }
1088 EXPORT_SYMBOL_GPL(unregister_candev);
1089
1090 /*
1091  * Test if a network device is a candev based device
1092  * and return the can_priv* if so.
1093  */
1094 struct can_priv *safe_candev_priv(struct net_device *dev)
1095 {
1096         if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1097                 return NULL;
1098
1099         return netdev_priv(dev);
1100 }
1101 EXPORT_SYMBOL_GPL(safe_candev_priv);
1102
1103 static __init int can_dev_init(void)
1104 {
1105         int err;
1106
1107         can_led_notifier_init();
1108
1109         err = rtnl_link_register(&can_link_ops);
1110         if (!err)
1111                 printk(KERN_INFO MOD_DESC "\n");
1112
1113         return err;
1114 }
1115 module_init(can_dev_init);
1116
1117 static __exit void can_dev_exit(void)
1118 {
1119         rtnl_link_unregister(&can_link_ops);
1120
1121         can_led_notifier_exit();
1122 }
1123 module_exit(can_dev_exit);
1124
1125 MODULE_ALIAS_RTNL_LINK("can");