1 // SPDX-License-Identifier: GPL-2.0-only 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 7 #include <linux/kernel.h> 8 #include <linux/slab.h> 9 #include <linux/netdevice.h> 10 #include <linux/if_arp.h> 11 #include <linux/workqueue.h> 12 #include <linux/can.h> 13 #include <linux/can/can-ml.h> 14 #include <linux/can/dev.h> 15 #include <linux/can/skb.h> 16 #include <linux/gpio/consumer.h> 17 #include <linux/of.h> 18 19 static void can_update_state_error_stats(struct net_device *dev, 20 enum can_state new_state) 21 { 22 struct can_priv *priv = netdev_priv(dev); 23 24 if (new_state <= priv->state) 25 return; 26 27 switch (new_state) { 28 case CAN_STATE_ERROR_WARNING: 29 priv->can_stats.error_warning++; 30 break; 31 case CAN_STATE_ERROR_PASSIVE: 32 priv->can_stats.error_passive++; 33 break; 34 case CAN_STATE_BUS_OFF: 35 priv->can_stats.bus_off++; 36 break; 37 default: 38 break; 39 } 40 } 41 42 static int can_tx_state_to_frame(struct net_device *dev, enum can_state state) 43 { 44 switch (state) { 45 case CAN_STATE_ERROR_ACTIVE: 46 return CAN_ERR_CRTL_ACTIVE; 47 case CAN_STATE_ERROR_WARNING: 48 return CAN_ERR_CRTL_TX_WARNING; 49 case CAN_STATE_ERROR_PASSIVE: 50 return CAN_ERR_CRTL_TX_PASSIVE; 51 default: 52 return 0; 53 } 54 } 55 56 static int can_rx_state_to_frame(struct net_device *dev, enum can_state state) 57 { 58 switch (state) { 59 case CAN_STATE_ERROR_ACTIVE: 60 return CAN_ERR_CRTL_ACTIVE; 61 case CAN_STATE_ERROR_WARNING: 62 return CAN_ERR_CRTL_RX_WARNING; 63 case CAN_STATE_ERROR_PASSIVE: 64 return CAN_ERR_CRTL_RX_PASSIVE; 65 default: 66 return 0; 67 } 68 } 69 70 const char *can_get_state_str(const enum can_state state) 71 { 72 switch (state) { 73 case CAN_STATE_ERROR_ACTIVE: 74 return "Error Active"; 75 case CAN_STATE_ERROR_WARNING: 76 return "Error Warning"; 77 case CAN_STATE_ERROR_PASSIVE: 78 return "Error Passive"; 79 case CAN_STATE_BUS_OFF: 80 return "Bus Off"; 81 case CAN_STATE_STOPPED: 82 return "Stopped"; 83 case CAN_STATE_SLEEPING: 84 return "Sleeping"; 85 default: 86 return "<unknown>"; 87 } 88 89 return "<unknown>"; 90 } 91 EXPORT_SYMBOL_GPL(can_get_state_str); 92 93 void can_change_state(struct net_device *dev, struct can_frame *cf, 94 enum can_state tx_state, enum can_state rx_state) 95 { 96 struct can_priv *priv = netdev_priv(dev); 97 enum can_state new_state = max(tx_state, rx_state); 98 99 if (unlikely(new_state == priv->state)) { 100 netdev_warn(dev, "%s: oops, state did not change", __func__); 101 return; 102 } 103 104 netdev_dbg(dev, "Controller changed from %s State (%d) into %s State (%d).\n", 105 can_get_state_str(priv->state), priv->state, 106 can_get_state_str(new_state), new_state); 107 108 can_update_state_error_stats(dev, new_state); 109 priv->state = new_state; 110 111 if (!cf) 112 return; 113 114 if (unlikely(new_state == CAN_STATE_BUS_OFF)) { 115 cf->can_id |= CAN_ERR_BUSOFF; 116 return; 117 } 118 119 cf->can_id |= CAN_ERR_CRTL; 120 cf->data[1] |= tx_state >= rx_state ? 121 can_tx_state_to_frame(dev, tx_state) : 0; 122 cf->data[1] |= tx_state <= rx_state ? 123 can_rx_state_to_frame(dev, rx_state) : 0; 124 } 125 EXPORT_SYMBOL_GPL(can_change_state); 126 127 /* CAN device restart for bus-off recovery */ 128 static void can_restart(struct net_device *dev) 129 { 130 struct can_priv *priv = netdev_priv(dev); 131 struct sk_buff *skb; 132 struct can_frame *cf; 133 int err; 134 135 BUG_ON(netif_carrier_ok(dev)); 136 137 /* No synchronization needed because the device is bus-off and 138 * no messages can come in or go out. 139 */ 140 can_flush_echo_skb(dev); 141 142 /* send restart message upstream */ 143 skb = alloc_can_err_skb(dev, &cf); 144 if (!skb) 145 goto restart; 146 147 cf->can_id |= CAN_ERR_RESTARTED; 148 149 netif_rx(skb); 150 151 restart: 152 netdev_dbg(dev, "restarted\n"); 153 priv->can_stats.restarts++; 154 155 /* Now restart the device */ 156 err = priv->do_set_mode(dev, CAN_MODE_START); 157 158 netif_carrier_on(dev); 159 if (err) 160 netdev_err(dev, "Error %d during restart", err); 161 } 162 163 static void can_restart_work(struct work_struct *work) 164 { 165 struct delayed_work *dwork = to_delayed_work(work); 166 struct can_priv *priv = container_of(dwork, struct can_priv, 167 restart_work); 168 169 can_restart(priv->dev); 170 } 171 172 int can_restart_now(struct net_device *dev) 173 { 174 struct can_priv *priv = netdev_priv(dev); 175 176 /* A manual restart is only permitted if automatic restart is 177 * disabled and the device is in the bus-off state 178 */ 179 if (priv->restart_ms) 180 return -EINVAL; 181 if (priv->state != CAN_STATE_BUS_OFF) 182 return -EBUSY; 183 184 cancel_delayed_work_sync(&priv->restart_work); 185 can_restart(dev); 186 187 return 0; 188 } 189 190 /* CAN bus-off 191 * 192 * This functions should be called when the device goes bus-off to 193 * tell the netif layer that no more packets can be sent or received. 194 * If enabled, a timer is started to trigger bus-off recovery. 195 */ 196 void can_bus_off(struct net_device *dev) 197 { 198 struct can_priv *priv = netdev_priv(dev); 199 200 if (priv->restart_ms) 201 netdev_info(dev, "bus-off, scheduling restart in %d ms\n", 202 priv->restart_ms); 203 else 204 netdev_info(dev, "bus-off\n"); 205 206 netif_carrier_off(dev); 207 208 if (priv->restart_ms) 209 schedule_delayed_work(&priv->restart_work, 210 msecs_to_jiffies(priv->restart_ms)); 211 } 212 EXPORT_SYMBOL_GPL(can_bus_off); 213 214 void can_setup(struct net_device *dev) 215 { 216 dev->type = ARPHRD_CAN; 217 dev->mtu = CAN_MTU; 218 dev->hard_header_len = 0; 219 dev->addr_len = 0; 220 dev->tx_queue_len = 10; 221 222 /* New-style flags. */ 223 dev->flags = IFF_NOARP; 224 dev->features = NETIF_F_HW_CSUM; 225 } 226 227 /* Allocate and setup space for the CAN network device */ 228 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max, 229 unsigned int txqs, unsigned int rxqs) 230 { 231 struct can_ml_priv *can_ml; 232 struct net_device *dev; 233 struct can_priv *priv; 234 int size; 235 236 /* We put the driver's priv, the CAN mid layer priv and the 237 * echo skb into the netdevice's priv. The memory layout for 238 * the netdev_priv is like this: 239 * 240 * +-------------------------+ 241 * | driver's priv | 242 * +-------------------------+ 243 * | struct can_ml_priv | 244 * +-------------------------+ 245 * | array of struct sk_buff | 246 * +-------------------------+ 247 */ 248 249 size = ALIGN(sizeof_priv, NETDEV_ALIGN) + sizeof(struct can_ml_priv); 250 251 if (echo_skb_max) 252 size = ALIGN(size, sizeof(struct sk_buff *)) + 253 echo_skb_max * sizeof(struct sk_buff *); 254 255 dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup, 256 txqs, rxqs); 257 if (!dev) 258 return NULL; 259 260 priv = netdev_priv(dev); 261 priv->dev = dev; 262 263 can_ml = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN); 264 can_set_ml_priv(dev, can_ml); 265 266 if (echo_skb_max) { 267 priv->echo_skb_max = echo_skb_max; 268 priv->echo_skb = (void *)priv + 269 (size - echo_skb_max * sizeof(struct sk_buff *)); 270 } 271 272 priv->state = CAN_STATE_STOPPED; 273 274 INIT_DELAYED_WORK(&priv->restart_work, can_restart_work); 275 276 return dev; 277 } 278 EXPORT_SYMBOL_GPL(alloc_candev_mqs); 279 280 /* Free space of the CAN network device */ 281 void free_candev(struct net_device *dev) 282 { 283 free_netdev(dev); 284 } 285 EXPORT_SYMBOL_GPL(free_candev); 286 287 /* changing MTU and control mode for CAN/CANFD devices */ 288 int can_change_mtu(struct net_device *dev, int new_mtu) 289 { 290 struct can_priv *priv = netdev_priv(dev); 291 u32 ctrlmode_static = can_get_static_ctrlmode(priv); 292 293 /* Do not allow changing the MTU while running */ 294 if (dev->flags & IFF_UP) 295 return -EBUSY; 296 297 /* allow change of MTU according to the CANFD ability of the device */ 298 switch (new_mtu) { 299 case CAN_MTU: 300 /* 'CANFD-only' controllers can not switch to CAN_MTU */ 301 if (ctrlmode_static & CAN_CTRLMODE_FD) 302 return -EINVAL; 303 304 priv->ctrlmode &= ~CAN_CTRLMODE_FD; 305 break; 306 307 case CANFD_MTU: 308 /* check for potential CANFD ability */ 309 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) && 310 !(ctrlmode_static & CAN_CTRLMODE_FD)) 311 return -EINVAL; 312 313 priv->ctrlmode |= CAN_CTRLMODE_FD; 314 break; 315 316 default: 317 return -EINVAL; 318 } 319 320 dev->mtu = new_mtu; 321 return 0; 322 } 323 EXPORT_SYMBOL_GPL(can_change_mtu); 324 325 /* generic implementation of netdev_ops::ndo_eth_ioctl for CAN devices 326 * supporting hardware timestamps 327 */ 328 int can_eth_ioctl_hwts(struct net_device *netdev, struct ifreq *ifr, int cmd) 329 { 330 struct hwtstamp_config hwts_cfg = { 0 }; 331 332 switch (cmd) { 333 case SIOCSHWTSTAMP: /* set */ 334 if (copy_from_user(&hwts_cfg, ifr->ifr_data, sizeof(hwts_cfg))) 335 return -EFAULT; 336 if (hwts_cfg.tx_type == HWTSTAMP_TX_ON && 337 hwts_cfg.rx_filter == HWTSTAMP_FILTER_ALL) 338 return 0; 339 return -ERANGE; 340 341 case SIOCGHWTSTAMP: /* get */ 342 hwts_cfg.tx_type = HWTSTAMP_TX_ON; 343 hwts_cfg.rx_filter = HWTSTAMP_FILTER_ALL; 344 if (copy_to_user(ifr->ifr_data, &hwts_cfg, sizeof(hwts_cfg))) 345 return -EFAULT; 346 return 0; 347 348 default: 349 return -EOPNOTSUPP; 350 } 351 } 352 EXPORT_SYMBOL(can_eth_ioctl_hwts); 353 354 /* generic implementation of ethtool_ops::get_ts_info for CAN devices 355 * supporting hardware timestamps 356 */ 357 int can_ethtool_op_get_ts_info_hwts(struct net_device *dev, 358 struct ethtool_ts_info *info) 359 { 360 info->so_timestamping = 361 SOF_TIMESTAMPING_TX_SOFTWARE | 362 SOF_TIMESTAMPING_RX_SOFTWARE | 363 SOF_TIMESTAMPING_SOFTWARE | 364 SOF_TIMESTAMPING_TX_HARDWARE | 365 SOF_TIMESTAMPING_RX_HARDWARE | 366 SOF_TIMESTAMPING_RAW_HARDWARE; 367 info->phc_index = -1; 368 info->tx_types = BIT(HWTSTAMP_TX_ON); 369 info->rx_filters = BIT(HWTSTAMP_FILTER_ALL); 370 371 return 0; 372 } 373 EXPORT_SYMBOL(can_ethtool_op_get_ts_info_hwts); 374 375 /* Common open function when the device gets opened. 376 * 377 * This function should be called in the open function of the device 378 * driver. 379 */ 380 int open_candev(struct net_device *dev) 381 { 382 struct can_priv *priv = netdev_priv(dev); 383 384 if (!priv->bittiming.bitrate) { 385 netdev_err(dev, "bit-timing not yet defined\n"); 386 return -EINVAL; 387 } 388 389 /* For CAN FD the data bitrate has to be >= the arbitration bitrate */ 390 if ((priv->ctrlmode & CAN_CTRLMODE_FD) && 391 (!priv->data_bittiming.bitrate || 392 priv->data_bittiming.bitrate < priv->bittiming.bitrate)) { 393 netdev_err(dev, "incorrect/missing data bit-timing\n"); 394 return -EINVAL; 395 } 396 397 /* Switch carrier on if device was stopped while in bus-off state */ 398 if (!netif_carrier_ok(dev)) 399 netif_carrier_on(dev); 400 401 return 0; 402 } 403 EXPORT_SYMBOL_GPL(open_candev); 404 405 #ifdef CONFIG_OF 406 /* Common function that can be used to understand the limitation of 407 * a transceiver when it provides no means to determine these limitations 408 * at runtime. 409 */ 410 void of_can_transceiver(struct net_device *dev) 411 { 412 struct device_node *dn; 413 struct can_priv *priv = netdev_priv(dev); 414 struct device_node *np = dev->dev.parent->of_node; 415 int ret; 416 417 dn = of_get_child_by_name(np, "can-transceiver"); 418 if (!dn) 419 return; 420 421 ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max); 422 of_node_put(dn); 423 if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max)) 424 netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n"); 425 } 426 EXPORT_SYMBOL_GPL(of_can_transceiver); 427 #endif 428 429 /* Common close function for cleanup before the device gets closed. 430 * 431 * This function should be called in the close function of the device 432 * driver. 433 */ 434 void close_candev(struct net_device *dev) 435 { 436 struct can_priv *priv = netdev_priv(dev); 437 438 cancel_delayed_work_sync(&priv->restart_work); 439 can_flush_echo_skb(dev); 440 } 441 EXPORT_SYMBOL_GPL(close_candev); 442 443 static int can_set_termination(struct net_device *ndev, u16 term) 444 { 445 struct can_priv *priv = netdev_priv(ndev); 446 int set; 447 448 if (term == priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_ENABLED]) 449 set = 1; 450 else 451 set = 0; 452 453 gpiod_set_value(priv->termination_gpio, set); 454 455 return 0; 456 } 457 458 static int can_get_termination(struct net_device *ndev) 459 { 460 struct can_priv *priv = netdev_priv(ndev); 461 struct device *dev = ndev->dev.parent; 462 struct gpio_desc *gpio; 463 u32 term; 464 int ret; 465 466 /* Disabling termination by default is the safe choice: Else if many 467 * bus participants enable it, no communication is possible at all. 468 */ 469 gpio = devm_gpiod_get_optional(dev, "termination", GPIOD_OUT_LOW); 470 if (IS_ERR(gpio)) 471 return dev_err_probe(dev, PTR_ERR(gpio), 472 "Cannot get termination-gpios\n"); 473 474 if (!gpio) 475 return 0; 476 477 ret = device_property_read_u32(dev, "termination-ohms", &term); 478 if (ret) { 479 netdev_err(ndev, "Cannot get termination-ohms: %pe\n", 480 ERR_PTR(ret)); 481 return ret; 482 } 483 484 if (term > U16_MAX) { 485 netdev_err(ndev, "Invalid termination-ohms value (%u > %u)\n", 486 term, U16_MAX); 487 return -EINVAL; 488 } 489 490 priv->termination_const_cnt = ARRAY_SIZE(priv->termination_gpio_ohms); 491 priv->termination_const = priv->termination_gpio_ohms; 492 priv->termination_gpio = gpio; 493 priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_DISABLED] = 494 CAN_TERMINATION_DISABLED; 495 priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_ENABLED] = term; 496 priv->do_set_termination = can_set_termination; 497 498 return 0; 499 } 500 501 static bool 502 can_bittiming_const_valid(const struct can_bittiming_const *btc) 503 { 504 if (!btc) 505 return true; 506 507 if (!btc->sjw_max) 508 return false; 509 510 return true; 511 } 512 513 /* Register the CAN network device */ 514 int register_candev(struct net_device *dev) 515 { 516 struct can_priv *priv = netdev_priv(dev); 517 int err; 518 519 /* Ensure termination_const, termination_const_cnt and 520 * do_set_termination consistency. All must be either set or 521 * unset. 522 */ 523 if ((!priv->termination_const != !priv->termination_const_cnt) || 524 (!priv->termination_const != !priv->do_set_termination)) 525 return -EINVAL; 526 527 if (!priv->bitrate_const != !priv->bitrate_const_cnt) 528 return -EINVAL; 529 530 if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt) 531 return -EINVAL; 532 533 /* We only support either fixed bit rates or bit timing const. */ 534 if ((priv->bitrate_const || priv->data_bitrate_const) && 535 (priv->bittiming_const || priv->data_bittiming_const)) 536 return -EINVAL; 537 538 if (!can_bittiming_const_valid(priv->bittiming_const) || 539 !can_bittiming_const_valid(priv->data_bittiming_const)) 540 return -EINVAL; 541 542 if (!priv->termination_const) { 543 err = can_get_termination(dev); 544 if (err) 545 return err; 546 } 547 548 dev->rtnl_link_ops = &can_link_ops; 549 netif_carrier_off(dev); 550 551 return register_netdev(dev); 552 } 553 EXPORT_SYMBOL_GPL(register_candev); 554 555 /* Unregister the CAN network device */ 556 void unregister_candev(struct net_device *dev) 557 { 558 unregister_netdev(dev); 559 } 560 EXPORT_SYMBOL_GPL(unregister_candev); 561 562 /* Test if a network device is a candev based device 563 * and return the can_priv* if so. 564 */ 565 struct can_priv *safe_candev_priv(struct net_device *dev) 566 { 567 if (dev->type != ARPHRD_CAN || dev->rtnl_link_ops != &can_link_ops) 568 return NULL; 569 570 return netdev_priv(dev); 571 } 572 EXPORT_SYMBOL_GPL(safe_candev_priv); 573 574 static __init int can_dev_init(void) 575 { 576 int err; 577 578 err = can_netlink_register(); 579 if (!err) 580 pr_info("CAN device driver interface\n"); 581 582 return err; 583 } 584 module_init(can_dev_init); 585 586 static __exit void can_dev_exit(void) 587 { 588 can_netlink_unregister(); 589 } 590 module_exit(can_dev_exit); 591 592 MODULE_ALIAS_RTNL_LINK("can"); 593