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 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
 457 {
 458         struct can_priv *priv = netdev_priv(dev);
 459
 460         if (idx >= priv->echo_skb_max) {
 461                 netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
 462                            __func__, idx, priv->echo_skb_max);
 463                 return NULL;
 464         }
 465
 466         if (priv->echo_skb[idx]) {
 467                 /* Using "struct canfd_frame::len" for the frame
 468                  * length is supported on both CAN and CANFD frames.
 469                  */
 470                 struct sk_buff *skb = priv->echo_skb[idx];
 471                 struct canfd_frame *cf = (struct canfd_frame *)skb->data;
 472
 473                 /* get the real payload length for netdev statistics */
 474                 if (cf->can_id & CAN_RTR_FLAG)
 475                         *len_ptr = 0;
 476                 else
 477                         *len_ptr = cf->len;
 478
 479                 priv->echo_skb[idx] = NULL;
 480
 481                 return skb;
 482         }
 483
 484         return NULL;
 485 }
 486
 487 /*
 488  * Get the skb from the stack and loop it back locally
 489  *
 490  * The function is typically called when the TX done interrupt
 491  * is handled in the device driver. The driver must protect
 492  * access to priv->echo_skb, if necessary.
 493  */
 494 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 495 {
 496         struct sk_buff *skb;
 497         u8 len;
 498
 499         skb = __can_get_echo_skb(dev, idx, &len);
 500         if (!skb)
 501                 return 0;
 502
 503         skb_get(skb);
 504         if (netif_rx(skb) == NET_RX_SUCCESS)
 505                 dev_consume_skb_any(skb);
 506         else
 507                 dev_kfree_skb_any(skb);
 508
 509         return len;
 510 }
 511 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 512
 513 /*
 514   * Remove the skb from the stack and free it.
 515   *
 516   * The function is typically called when TX failed.
 517   */
 518 void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 519 {
 520         struct can_priv *priv = netdev_priv(dev);
 521
 522         BUG_ON(idx >= priv->echo_skb_max);
 523
 524         if (priv->echo_skb[idx]) {
 525                 dev_kfree_skb_any(priv->echo_skb[idx]);
 526                 priv->echo_skb[idx] = NULL;
 527         }
 528 }
 529 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 530
 531 /*
 532  * CAN device restart for bus-off recovery
 533  */
 534 static void can_restart(struct net_device *dev)
 535 {
 536         struct can_priv *priv = netdev_priv(dev);
 537         struct net_device_stats *stats = &dev->stats;
 538         struct sk_buff *skb;
 539         struct can_frame *cf;
 540         int err;
 541
 542         BUG_ON(netif_carrier_ok(dev));
 543
 544         /*
 545          * No synchronization needed because the device is bus-off and
 546          * no messages can come in or go out.
 547          */
 548         can_flush_echo_skb(dev);
 549
 550         /* send restart message upstream */
 551         skb = alloc_can_err_skb(dev, &cf);
 552         if (skb == NULL) {
 553                 err = -ENOMEM;
 554                 goto restart;
 555         }
 556         cf->can_id |= CAN_ERR_RESTARTED;
 557
 558         stats->rx_packets++;
 559         stats->rx_bytes += cf->can_dlc;
 560
 561         netif_rx_ni(skb);
 562
 563 restart:
 564         netdev_dbg(dev, "restarted\n");
 565         priv->can_stats.restarts++;
 566
 567         /* Now restart the device */
 568         err = priv->do_set_mode(dev, CAN_MODE_START);
 569
 570         netif_carrier_on(dev);
 571         if (err)
 572                 netdev_err(dev, "Error %d during restart", err);
 573 }
 574
 575 static void can_restart_work(struct work_struct *work)
 576 {
 577         struct delayed_work *dwork = to_delayed_work(work);
 578         struct can_priv *priv = container_of(dwork, struct can_priv, restart_work);
 579
 580         can_restart(priv->dev);
 581 }
 582
 583 int can_restart_now(struct net_device *dev)
 584 {
 585         struct can_priv *priv = netdev_priv(dev);
 586
 587         /*
 588          * A manual restart is only permitted if automatic restart is
 589          * disabled and the device is in the bus-off state
 590          */
 591         if (priv->restart_ms)
 592                 return -EINVAL;
 593         if (priv->state != CAN_STATE_BUS_OFF)
 594                 return -EBUSY;
 595
 596         cancel_delayed_work_sync(&priv->restart_work);
 597         can_restart(dev);
 598
 599         return 0;
 600 }
 601
 602 /*
 603  * CAN bus-off
 604  *
 605  * This functions should be called when the device goes bus-off to
 606  * tell the netif layer that no more packets can be sent or received.
 607  * If enabled, a timer is started to trigger bus-off recovery.
 608  */
 609 void can_bus_off(struct net_device *dev)
 610 {
 611         struct can_priv *priv = netdev_priv(dev);
 612
 613         netdev_dbg(dev, "bus-off\n");
 614
 615         netif_carrier_off(dev);
 616
 617         if (priv->restart_ms)
 618                 schedule_delayed_work(&priv->restart_work,
 619                                       msecs_to_jiffies(priv->restart_ms));
 620 }
 621 EXPORT_SYMBOL_GPL(can_bus_off);
 622
 623 static void can_setup(struct net_device *dev)
 624 {
 625         dev->type = ARPHRD_CAN;
 626         dev->mtu = CAN_MTU;
 627         dev->hard_header_len = 0;
 628         dev->addr_len = 0;
 629         dev->tx_queue_len = 10;
 630
 631         /* New-style flags. */
 632         dev->flags = IFF_NOARP;
 633         dev->features = NETIF_F_HW_CSUM;
 634 }
 635
 636 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 637 {
 638         struct sk_buff *skb;
 639
 640         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 641                                sizeof(struct can_frame));
 642         if (unlikely(!skb))
 643                 return NULL;
 644
 645         skb->protocol = htons(ETH_P_CAN);
 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         *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
 658         memset(*cf, 0, sizeof(struct can_frame));
 659
 660         return skb;
 661 }
 662 EXPORT_SYMBOL_GPL(alloc_can_skb);
 663
 664 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 665                                 struct canfd_frame **cfd)
 666 {
 667         struct sk_buff *skb;
 668
 669         skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
 670                                sizeof(struct canfd_frame));
 671         if (unlikely(!skb))
 672                 return NULL;
 673
 674         skb->protocol = htons(ETH_P_CANFD);
 675         skb->pkt_type = PACKET_BROADCAST;
 676         skb->ip_summed = CHECKSUM_UNNECESSARY;
 677
 678         skb_reset_mac_header(skb);
 679         skb_reset_network_header(skb);
 680         skb_reset_transport_header(skb);
 681
 682         can_skb_reserve(skb);
 683         can_skb_prv(skb)->ifindex = dev->ifindex;
 684         can_skb_prv(skb)->skbcnt = 0;
 685
 686         *cfd = (struct canfd_frame *)skb_put(skb, sizeof(struct canfd_frame));
 687         memset(*cfd, 0, sizeof(struct canfd_frame));
 688
 689         return skb;
 690 }
 691 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 692
 693 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 694 {
 695         struct sk_buff *skb;
 696
 697         skb = alloc_can_skb(dev, cf);
 698         if (unlikely(!skb))
 699                 return NULL;
 700
 701         (*cf)->can_id = CAN_ERR_FLAG;
 702         (*cf)->can_dlc = CAN_ERR_DLC;
 703
 704         return skb;
 705 }
 706 EXPORT_SYMBOL_GPL(alloc_can_err_skb);
 707
 708 /*
 709  * Allocate and setup space for the CAN network device
 710  */
 711 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
 712 {
 713         struct net_device *dev;
 714         struct can_priv *priv;
 715         int size;
 716
 717         if (echo_skb_max)
 718                 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
 719                         echo_skb_max * sizeof(struct sk_buff *);
 720         else
 721                 size = sizeof_priv;
 722
 723         dev = alloc_netdev(size, "can%d", NET_NAME_UNKNOWN, can_setup);
 724         if (!dev)
 725                 return NULL;
 726
 727         priv = netdev_priv(dev);
 728         priv->dev = dev;
 729
 730         if (echo_skb_max) {
 731                 priv->echo_skb_max = echo_skb_max;
 732                 priv->echo_skb = (void *)priv +
 733                         ALIGN(sizeof_priv, sizeof(struct sk_buff *));
 734         }
 735
 736         priv->state = CAN_STATE_STOPPED;
 737
 738         INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
 739
 740         return dev;
 741 }
 742 EXPORT_SYMBOL_GPL(alloc_candev);
 743
 744 /*
 745  * Free space of the CAN network device
 746  */
 747 void free_candev(struct net_device *dev)
 748 {
 749         free_netdev(dev);
 750 }
 751 EXPORT_SYMBOL_GPL(free_candev);
 752
 753 /*
 754  * changing MTU and control mode for CAN/CANFD devices
 755  */
 756 int can_change_mtu(struct net_device *dev, int new_mtu)
 757 {
 758         struct can_priv *priv = netdev_priv(dev);
 759
 760         /* Do not allow changing the MTU while running */
 761         if (dev->flags & IFF_UP)
 762                 return -EBUSY;
 763
 764         /* allow change of MTU according to the CANFD ability of the device */
 765         switch (new_mtu) {
 766         case CAN_MTU:
 767                 /* 'CANFD-only' controllers can not switch to CAN_MTU */
 768                 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
 769                         return -EINVAL;
 770
 771                 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
 772                 break;
 773
 774         case CANFD_MTU:
 775                 /* check for potential CANFD ability */
 776                 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
 777                     !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
 778                         return -EINVAL;
 779
 780                 priv->ctrlmode |= CAN_CTRLMODE_FD;
 781                 break;
 782
 783         default:
 784                 return -EINVAL;
 785         }
 786
 787         dev->mtu = new_mtu;
 788         return 0;
 789 }
 790 EXPORT_SYMBOL_GPL(can_change_mtu);
 791
 792 /*
 793  * Common open function when the device gets opened.
 794  *
 795  * This function should be called in the open function of the device
 796  * driver.
 797  */
 798 int open_candev(struct net_device *dev)
 799 {
 800         struct can_priv *priv = netdev_priv(dev);
 801
 802         if (!priv->bittiming.bitrate) {
 803                 netdev_err(dev, "bit-timing not yet defined\n");
 804                 return -EINVAL;
 805         }
 806
 807         /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
 808         if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
 809             (!priv->data_bittiming.bitrate ||
 810              (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
 811                 netdev_err(dev, "incorrect/missing data bit-timing\n");
 812                 return -EINVAL;
 813         }
 814
 815         /* Switch carrier on if device was stopped while in bus-off state */
 816         if (!netif_carrier_ok(dev))
 817                 netif_carrier_on(dev);
 818
 819         return 0;
 820 }
 821 EXPORT_SYMBOL_GPL(open_candev);
 822
 823 /*
 824  * Common close function for cleanup before the device gets closed.
 825  *
 826  * This function should be called in the close function of the device
 827  * driver.
 828  */
 829 void close_candev(struct net_device *dev)
 830 {
 831         struct can_priv *priv = netdev_priv(dev);
 832
 833         cancel_delayed_work_sync(&priv->restart_work);
 834         can_flush_echo_skb(dev);
 835 }
 836 EXPORT_SYMBOL_GPL(close_candev);
 837
 838 /*
 839  * CAN netlink interface
 840  */
 841 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
 842         [IFLA_CAN_STATE]        = { .type = NLA_U32 },
 843         [IFLA_CAN_CTRLMODE]     = { .len = sizeof(struct can_ctrlmode) },
 844         [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
 845         [IFLA_CAN_RESTART]      = { .type = NLA_U32 },
 846         [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
 847         [IFLA_CAN_BITTIMING_CONST]
 848                                 = { .len = sizeof(struct can_bittiming_const) },
 849         [IFLA_CAN_CLOCK]        = { .len = sizeof(struct can_clock) },
 850         [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
 851         [IFLA_CAN_DATA_BITTIMING]
 852                                 = { .len = sizeof(struct can_bittiming) },
 853         [IFLA_CAN_DATA_BITTIMING_CONST]
 854                                 = { .len = sizeof(struct can_bittiming_const) },
 855 };
 856
 857 static int can_validate(struct nlattr *tb[], struct nlattr *data[])
 858 {
 859         bool is_can_fd = false;
 860
 861         /* Make sure that valid CAN FD configurations always consist of
 862          * - nominal/arbitration bittiming
 863          * - data bittiming
 864          * - control mode with CAN_CTRLMODE_FD set
 865          */
 866
 867         if (!data)
 868                 return 0;
 869
 870         if (data[IFLA_CAN_CTRLMODE]) {
 871                 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 872
 873                 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
 874         }
 875
 876         if (is_can_fd) {
 877                 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
 878                         return -EOPNOTSUPP;
 879         }
 880
 881         if (data[IFLA_CAN_DATA_BITTIMING]) {
 882                 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
 883                         return -EOPNOTSUPP;
 884         }
 885
 886         return 0;
 887 }
 888
 889 static int can_changelink(struct net_device *dev,
 890                           struct nlattr *tb[], struct nlattr *data[])
 891 {
 892         struct can_priv *priv = netdev_priv(dev);
 893         int err;
 894
 895         /* We need synchronization with dev->stop() */
 896         ASSERT_RTNL();
 897
 898         if (data[IFLA_CAN_BITTIMING]) {
 899                 struct can_bittiming bt;
 900
 901                 /* Do not allow changing bittiming while running */
 902                 if (dev->flags & IFF_UP)
 903                         return -EBUSY;
 904                 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
 905                 err = can_get_bittiming(dev, &bt, priv->bittiming_const);
 906                 if (err)
 907                         return err;
 908                 memcpy(&priv->bittiming, &bt, sizeof(bt));
 909
 910                 if (priv->do_set_bittiming) {
 911                         /* Finally, set the bit-timing registers */
 912                         err = priv->do_set_bittiming(dev);
 913                         if (err)
 914                                 return err;
 915                 }
 916         }
 917
 918         if (data[IFLA_CAN_CTRLMODE]) {
 919                 struct can_ctrlmode *cm;
 920                 u32 ctrlstatic;
 921                 u32 maskedflags;
 922
 923                 /* Do not allow changing controller mode while running */
 924                 if (dev->flags & IFF_UP)
 925                         return -EBUSY;
 926                 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
 927                 ctrlstatic = priv->ctrlmode_static;
 928                 maskedflags = cm->flags & cm->mask;
 929
 930                 /* check whether provided bits are allowed to be passed */
 931                 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
 932                         return -EOPNOTSUPP;
 933
 934                 /* do not check for static fd-non-iso if 'fd' is disabled */
 935                 if (!(maskedflags & CAN_CTRLMODE_FD))
 936                         ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
 937
 938                 /* make sure static options are provided by configuration */
 939                 if ((maskedflags & ctrlstatic) != ctrlstatic)
 940                         return -EOPNOTSUPP;
 941
 942                 /* clear bits to be modified and copy the flag values */
 943                 priv->ctrlmode &= ~cm->mask;
 944                 priv->ctrlmode |= maskedflags;
 945
 946                 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
 947                 if (priv->ctrlmode & CAN_CTRLMODE_FD)
 948                         dev->mtu = CANFD_MTU;
 949                 else
 950                         dev->mtu = CAN_MTU;
 951         }
 952
 953         if (data[IFLA_CAN_RESTART_MS]) {
 954                 /* Do not allow changing restart delay while running */
 955                 if (dev->flags & IFF_UP)
 956                         return -EBUSY;
 957                 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
 958         }
 959
 960         if (data[IFLA_CAN_RESTART]) {
 961                 /* Do not allow a restart while not running */
 962                 if (!(dev->flags & IFF_UP))
 963                         return -EINVAL;
 964                 err = can_restart_now(dev);
 965                 if (err)
 966                         return err;
 967         }
 968
 969         if (data[IFLA_CAN_DATA_BITTIMING]) {
 970                 struct can_bittiming dbt;
 971
 972                 /* Do not allow changing bittiming while running */
 973                 if (dev->flags & IFF_UP)
 974                         return -EBUSY;
 975                 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
 976                        sizeof(dbt));
 977                 err = can_get_bittiming(dev, &dbt, priv->data_bittiming_const);
 978                 if (err)
 979                         return err;
 980                 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
 981
 982                 if (priv->do_set_data_bittiming) {
 983                         /* Finally, set the bit-timing registers */
 984                         err = priv->do_set_data_bittiming(dev);
 985                         if (err)
 986                                 return err;
 987                 }
 988         }
 989
 990         return 0;
 991 }
 992
 993 static size_t can_get_size(const struct net_device *dev)
 994 {
 995         struct can_priv *priv = netdev_priv(dev);
 996         size_t size = 0;
 997
 998         if (priv->bittiming.bitrate)                            /* IFLA_CAN_BITTIMING */
 999                 size += nla_total_size(sizeof(struct can_bittiming));
1000         if (priv->bittiming_const)                              /* IFLA_CAN_BITTIMING_CONST */
1001                 size += nla_total_size(sizeof(struct can_bittiming_const));
1002         size += nla_total_size(sizeof(struct can_clock));       /* IFLA_CAN_CLOCK */
1003         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_STATE */
1004         size += nla_total_size(sizeof(struct can_ctrlmode));    /* IFLA_CAN_CTRLMODE */
1005         size += nla_total_size(sizeof(u32));                    /* IFLA_CAN_RESTART_MS */
1006         if (priv->do_get_berr_counter)                          /* IFLA_CAN_BERR_COUNTER */
1007                 size += nla_total_size(sizeof(struct can_berr_counter));
1008         if (priv->data_bittiming.bitrate)                       /* IFLA_CAN_DATA_BITTIMING */
1009                 size += nla_total_size(sizeof(struct can_bittiming));
1010         if (priv->data_bittiming_const)                         /* IFLA_CAN_DATA_BITTIMING_CONST */
1011                 size += nla_total_size(sizeof(struct can_bittiming_const));
1012
1013         return size;
1014 }
1015
1016 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
1017 {
1018         struct can_priv *priv = netdev_priv(dev);
1019         struct can_ctrlmode cm = {.flags = priv->ctrlmode};
1020         struct can_berr_counter bec = { };
1021         enum can_state state = priv->state;
1022
1023         if (priv->do_get_state)
1024                 priv->do_get_state(dev, &state);
1025
1026         if ((priv->bittiming.bitrate &&
1027              nla_put(skb, IFLA_CAN_BITTIMING,
1028                      sizeof(priv->bittiming), &priv->bittiming)) ||
1029
1030             (priv->bittiming_const &&
1031              nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1032                      sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1033
1034             nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1035             nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1036             nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1037             nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1038
1039             (priv->do_get_berr_counter &&
1040              !priv->do_get_berr_counter(dev, &bec) &&
1041              nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1042
1043             (priv->data_bittiming.bitrate &&
1044              nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1045                      sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1046
1047             (priv->data_bittiming_const &&
1048              nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1049                      sizeof(*priv->data_bittiming_const),
1050                      priv->data_bittiming_const)))
1051                 return -EMSGSIZE;
1052
1053         return 0;
1054 }
1055
1056 static size_t can_get_xstats_size(const struct net_device *dev)
1057 {
1058         return sizeof(struct can_device_stats);
1059 }
1060
1061 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1062 {
1063         struct can_priv *priv = netdev_priv(dev);
1064
1065         if (nla_put(skb, IFLA_INFO_XSTATS,
1066                     sizeof(priv->can_stats), &priv->can_stats))
1067                 goto nla_put_failure;
1068         return 0;
1069
1070 nla_put_failure:
1071         return -EMSGSIZE;
1072 }
1073
1074 static int can_newlink(struct net *src_net, struct net_device *dev,
1075                        struct nlattr *tb[], struct nlattr *data[])
1076 {
1077         return -EOPNOTSUPP;
1078 }
1079
1080 static void can_dellink(struct net_device *dev, struct list_head *head)
1081 {
1082         return;
1083 }
1084
1085 static struct rtnl_link_ops can_link_ops __read_mostly = {
1086         .kind           = "can",
1087         .netns_refund   = true,
1088         .maxtype        = IFLA_CAN_MAX,
1089         .policy         = can_policy,
1090         .setup          = can_setup,
1091         .validate       = can_validate,
1092         .newlink        = can_newlink,
1093         .changelink     = can_changelink,
1094         .dellink        = can_dellink,
1095         .get_size       = can_get_size,
1096         .fill_info      = can_fill_info,
1097         .get_xstats_size = can_get_xstats_size,
1098         .fill_xstats    = can_fill_xstats,
1099 };
1100
1101 /*
1102  * Register the CAN network device
1103  */
1104 int register_candev(struct net_device *dev)
1105 {
1106         dev->rtnl_link_ops = &can_link_ops;
1107         netif_carrier_off(dev);
1108
1109         return register_netdev(dev);
1110 }
1111 EXPORT_SYMBOL_GPL(register_candev);
1112
1113 /*
1114  * Unregister the CAN network device
1115  */
1116 void unregister_candev(struct net_device *dev)
1117 {
1118         unregister_netdev(dev);
1119 }
1120 EXPORT_SYMBOL_GPL(unregister_candev);
1121
1122 /*
1123  * Test if a network device is a candev based device
1124  * and return the can_priv* if so.
1125  */
1126 struct can_priv *safe_candev_priv(struct net_device *dev)
1127 {
1128         if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1129                 return NULL;
1130
1131         return netdev_priv(dev);
1132 }
1133 EXPORT_SYMBOL_GPL(safe_candev_priv);
1134
1135 static __init int can_dev_init(void)
1136 {
1137         int err;
1138
1139         can_led_notifier_init();
1140
1141         err = rtnl_link_register(&can_link_ops);
1142         if (!err)
1143                 printk(KERN_INFO MOD_DESC "\n");
1144
1145         return err;
1146 }
1147 module_init(can_dev_init);
1148
1149 static __exit void can_dev_exit(void)
1150 {
1151         rtnl_link_unregister(&can_link_ops);
1152
1153         can_led_notifier_exit();
1154 }
1155 module_exit(can_dev_exit);
1156
1157 MODULE_ALIAS_RTNL_LINK("can");