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/module.h> 8 #include <linux/kernel.h> 9 #include <linux/slab.h> 10 #include <linux/netdevice.h> 11 #include <linux/if_arp.h> 12 #include <linux/workqueue.h> 13 #include <linux/can.h> 14 #include <linux/can/can-ml.h> 15 #include <linux/can/dev.h> 16 #include <linux/can/skb.h> 17 #include <linux/can/led.h> 18 #include <linux/of.h> 19 20 #define MOD_DESC "CAN device driver interface" 21 22 MODULE_DESCRIPTION(MOD_DESC); 23 MODULE_LICENSE("GPL v2"); 24 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>"); 25 26 static void can_update_state_error_stats(struct net_device *dev, 27 enum can_state new_state) 28 { 29 struct can_priv *priv = netdev_priv(dev); 30 31 if (new_state <= priv->state) 32 return; 33 34 switch (new_state) { 35 case CAN_STATE_ERROR_WARNING: 36 priv->can_stats.error_warning++; 37 break; 38 case CAN_STATE_ERROR_PASSIVE: 39 priv->can_stats.error_passive++; 40 break; 41 case CAN_STATE_BUS_OFF: 42 priv->can_stats.bus_off++; 43 break; 44 default: 45 break; 46 } 47 } 48 49 static int can_tx_state_to_frame(struct net_device *dev, enum can_state state) 50 { 51 switch (state) { 52 case CAN_STATE_ERROR_ACTIVE: 53 return CAN_ERR_CRTL_ACTIVE; 54 case CAN_STATE_ERROR_WARNING: 55 return CAN_ERR_CRTL_TX_WARNING; 56 case CAN_STATE_ERROR_PASSIVE: 57 return CAN_ERR_CRTL_TX_PASSIVE; 58 default: 59 return 0; 60 } 61 } 62 63 static int can_rx_state_to_frame(struct net_device *dev, enum can_state state) 64 { 65 switch (state) { 66 case CAN_STATE_ERROR_ACTIVE: 67 return CAN_ERR_CRTL_ACTIVE; 68 case CAN_STATE_ERROR_WARNING: 69 return CAN_ERR_CRTL_RX_WARNING; 70 case CAN_STATE_ERROR_PASSIVE: 71 return CAN_ERR_CRTL_RX_PASSIVE; 72 default: 73 return 0; 74 } 75 } 76 77 const char *can_get_state_str(const enum can_state state) 78 { 79 switch (state) { 80 case CAN_STATE_ERROR_ACTIVE: 81 return "Error Active"; 82 case CAN_STATE_ERROR_WARNING: 83 return "Error Warning"; 84 case CAN_STATE_ERROR_PASSIVE: 85 return "Error Passive"; 86 case CAN_STATE_BUS_OFF: 87 return "Bus Off"; 88 case CAN_STATE_STOPPED: 89 return "Stopped"; 90 case CAN_STATE_SLEEPING: 91 return "Sleeping"; 92 default: 93 return "<unknown>"; 94 } 95 96 return "<unknown>"; 97 } 98 EXPORT_SYMBOL_GPL(can_get_state_str); 99 100 void can_change_state(struct net_device *dev, struct can_frame *cf, 101 enum can_state tx_state, enum can_state rx_state) 102 { 103 struct can_priv *priv = netdev_priv(dev); 104 enum can_state new_state = max(tx_state, rx_state); 105 106 if (unlikely(new_state == priv->state)) { 107 netdev_warn(dev, "%s: oops, state did not change", __func__); 108 return; 109 } 110 111 netdev_dbg(dev, "Controller changed from %s State (%d) into %s State (%d).\n", 112 can_get_state_str(priv->state), priv->state, 113 can_get_state_str(new_state), new_state); 114 115 can_update_state_error_stats(dev, new_state); 116 priv->state = new_state; 117 118 if (!cf) 119 return; 120 121 if (unlikely(new_state == CAN_STATE_BUS_OFF)) { 122 cf->can_id |= CAN_ERR_BUSOFF; 123 return; 124 } 125 126 cf->can_id |= CAN_ERR_CRTL; 127 cf->data[1] |= tx_state >= rx_state ? 128 can_tx_state_to_frame(dev, tx_state) : 0; 129 cf->data[1] |= tx_state <= rx_state ? 130 can_rx_state_to_frame(dev, rx_state) : 0; 131 } 132 EXPORT_SYMBOL_GPL(can_change_state); 133 134 /* CAN device restart for bus-off recovery */ 135 static void can_restart(struct net_device *dev) 136 { 137 struct can_priv *priv = netdev_priv(dev); 138 struct net_device_stats *stats = &dev->stats; 139 struct sk_buff *skb; 140 struct can_frame *cf; 141 int err; 142 143 BUG_ON(netif_carrier_ok(dev)); 144 145 /* No synchronization needed because the device is bus-off and 146 * no messages can come in or go out. 147 */ 148 can_flush_echo_skb(dev); 149 150 /* send restart message upstream */ 151 skb = alloc_can_err_skb(dev, &cf); 152 if (!skb) 153 goto restart; 154 155 cf->can_id |= CAN_ERR_RESTARTED; 156 157 stats->rx_packets++; 158 stats->rx_bytes += cf->len; 159 160 netif_rx_ni(skb); 161 162 restart: 163 netdev_dbg(dev, "restarted\n"); 164 priv->can_stats.restarts++; 165 166 /* Now restart the device */ 167 err = priv->do_set_mode(dev, CAN_MODE_START); 168 169 netif_carrier_on(dev); 170 if (err) 171 netdev_err(dev, "Error %d during restart", err); 172 } 173 174 static void can_restart_work(struct work_struct *work) 175 { 176 struct delayed_work *dwork = to_delayed_work(work); 177 struct can_priv *priv = container_of(dwork, struct can_priv, 178 restart_work); 179 180 can_restart(priv->dev); 181 } 182 183 int can_restart_now(struct net_device *dev) 184 { 185 struct can_priv *priv = netdev_priv(dev); 186 187 /* A manual restart is only permitted if automatic restart is 188 * disabled and the device is in the bus-off state 189 */ 190 if (priv->restart_ms) 191 return -EINVAL; 192 if (priv->state != CAN_STATE_BUS_OFF) 193 return -EBUSY; 194 195 cancel_delayed_work_sync(&priv->restart_work); 196 can_restart(dev); 197 198 return 0; 199 } 200 201 /* CAN bus-off 202 * 203 * This functions should be called when the device goes bus-off to 204 * tell the netif layer that no more packets can be sent or received. 205 * If enabled, a timer is started to trigger bus-off recovery. 206 */ 207 void can_bus_off(struct net_device *dev) 208 { 209 struct can_priv *priv = netdev_priv(dev); 210 211 if (priv->restart_ms) 212 netdev_info(dev, "bus-off, scheduling restart in %d ms\n", 213 priv->restart_ms); 214 else 215 netdev_info(dev, "bus-off\n"); 216 217 netif_carrier_off(dev); 218 219 if (priv->restart_ms) 220 schedule_delayed_work(&priv->restart_work, 221 msecs_to_jiffies(priv->restart_ms)); 222 } 223 EXPORT_SYMBOL_GPL(can_bus_off); 224 225 void can_setup(struct net_device *dev) 226 { 227 dev->type = ARPHRD_CAN; 228 dev->mtu = CAN_MTU; 229 dev->hard_header_len = 0; 230 dev->addr_len = 0; 231 dev->tx_queue_len = 10; 232 233 /* New-style flags. */ 234 dev->flags = IFF_NOARP; 235 dev->features = NETIF_F_HW_CSUM; 236 } 237 238 /* Allocate and setup space for the CAN network device */ 239 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max, 240 unsigned int txqs, unsigned int rxqs) 241 { 242 struct net_device *dev; 243 struct can_priv *priv; 244 int size; 245 246 /* We put the driver's priv, the CAN mid layer priv and the 247 * echo skb into the netdevice's priv. The memory layout for 248 * the netdev_priv is like this: 249 * 250 * +-------------------------+ 251 * | driver's priv | 252 * +-------------------------+ 253 * | struct can_ml_priv | 254 * +-------------------------+ 255 * | array of struct sk_buff | 256 * +-------------------------+ 257 */ 258 259 size = ALIGN(sizeof_priv, NETDEV_ALIGN) + sizeof(struct can_ml_priv); 260 261 if (echo_skb_max) 262 size = ALIGN(size, sizeof(struct sk_buff *)) + 263 echo_skb_max * sizeof(struct sk_buff *); 264 265 dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup, 266 txqs, rxqs); 267 if (!dev) 268 return NULL; 269 270 priv = netdev_priv(dev); 271 priv->dev = dev; 272 273 dev->ml_priv = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN); 274 275 if (echo_skb_max) { 276 priv->echo_skb_max = echo_skb_max; 277 priv->echo_skb = (void *)priv + 278 (size - echo_skb_max * sizeof(struct sk_buff *)); 279 } 280 281 priv->state = CAN_STATE_STOPPED; 282 283 INIT_DELAYED_WORK(&priv->restart_work, can_restart_work); 284 285 return dev; 286 } 287 EXPORT_SYMBOL_GPL(alloc_candev_mqs); 288 289 /* Free space of the CAN network device */ 290 void free_candev(struct net_device *dev) 291 { 292 free_netdev(dev); 293 } 294 EXPORT_SYMBOL_GPL(free_candev); 295 296 /* changing MTU and control mode for CAN/CANFD devices */ 297 int can_change_mtu(struct net_device *dev, int new_mtu) 298 { 299 struct can_priv *priv = netdev_priv(dev); 300 301 /* Do not allow changing the MTU while running */ 302 if (dev->flags & IFF_UP) 303 return -EBUSY; 304 305 /* allow change of MTU according to the CANFD ability of the device */ 306 switch (new_mtu) { 307 case CAN_MTU: 308 /* 'CANFD-only' controllers can not switch to CAN_MTU */ 309 if (priv->ctrlmode_static & CAN_CTRLMODE_FD) 310 return -EINVAL; 311 312 priv->ctrlmode &= ~CAN_CTRLMODE_FD; 313 break; 314 315 case CANFD_MTU: 316 /* check for potential CANFD ability */ 317 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) && 318 !(priv->ctrlmode_static & CAN_CTRLMODE_FD)) 319 return -EINVAL; 320 321 priv->ctrlmode |= CAN_CTRLMODE_FD; 322 break; 323 324 default: 325 return -EINVAL; 326 } 327 328 dev->mtu = new_mtu; 329 return 0; 330 } 331 EXPORT_SYMBOL_GPL(can_change_mtu); 332 333 /* Common open function when the device gets opened. 334 * 335 * This function should be called in the open function of the device 336 * driver. 337 */ 338 int open_candev(struct net_device *dev) 339 { 340 struct can_priv *priv = netdev_priv(dev); 341 342 if (!priv->bittiming.bitrate) { 343 netdev_err(dev, "bit-timing not yet defined\n"); 344 return -EINVAL; 345 } 346 347 /* For CAN FD the data bitrate has to be >= the arbitration bitrate */ 348 if ((priv->ctrlmode & CAN_CTRLMODE_FD) && 349 (!priv->data_bittiming.bitrate || 350 priv->data_bittiming.bitrate < priv->bittiming.bitrate)) { 351 netdev_err(dev, "incorrect/missing data bit-timing\n"); 352 return -EINVAL; 353 } 354 355 /* Switch carrier on if device was stopped while in bus-off state */ 356 if (!netif_carrier_ok(dev)) 357 netif_carrier_on(dev); 358 359 return 0; 360 } 361 EXPORT_SYMBOL_GPL(open_candev); 362 363 #ifdef CONFIG_OF 364 /* Common function that can be used to understand the limitation of 365 * a transceiver when it provides no means to determine these limitations 366 * at runtime. 367 */ 368 void of_can_transceiver(struct net_device *dev) 369 { 370 struct device_node *dn; 371 struct can_priv *priv = netdev_priv(dev); 372 struct device_node *np = dev->dev.parent->of_node; 373 int ret; 374 375 dn = of_get_child_by_name(np, "can-transceiver"); 376 if (!dn) 377 return; 378 379 ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max); 380 of_node_put(dn); 381 if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max)) 382 netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n"); 383 } 384 EXPORT_SYMBOL_GPL(of_can_transceiver); 385 #endif 386 387 /* Common close function for cleanup before the device gets closed. 388 * 389 * This function should be called in the close function of the device 390 * driver. 391 */ 392 void close_candev(struct net_device *dev) 393 { 394 struct can_priv *priv = netdev_priv(dev); 395 396 cancel_delayed_work_sync(&priv->restart_work); 397 can_flush_echo_skb(dev); 398 } 399 EXPORT_SYMBOL_GPL(close_candev); 400 401 /* Register the CAN network device */ 402 int register_candev(struct net_device *dev) 403 { 404 struct can_priv *priv = netdev_priv(dev); 405 406 /* Ensure termination_const, termination_const_cnt and 407 * do_set_termination consistency. All must be either set or 408 * unset. 409 */ 410 if ((!priv->termination_const != !priv->termination_const_cnt) || 411 (!priv->termination_const != !priv->do_set_termination)) 412 return -EINVAL; 413 414 if (!priv->bitrate_const != !priv->bitrate_const_cnt) 415 return -EINVAL; 416 417 if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt) 418 return -EINVAL; 419 420 dev->rtnl_link_ops = &can_link_ops; 421 netif_carrier_off(dev); 422 423 return register_netdev(dev); 424 } 425 EXPORT_SYMBOL_GPL(register_candev); 426 427 /* Unregister the CAN network device */ 428 void unregister_candev(struct net_device *dev) 429 { 430 unregister_netdev(dev); 431 } 432 EXPORT_SYMBOL_GPL(unregister_candev); 433 434 /* Test if a network device is a candev based device 435 * and return the can_priv* if so. 436 */ 437 struct can_priv *safe_candev_priv(struct net_device *dev) 438 { 439 if (dev->type != ARPHRD_CAN || dev->rtnl_link_ops != &can_link_ops) 440 return NULL; 441 442 return netdev_priv(dev); 443 } 444 EXPORT_SYMBOL_GPL(safe_candev_priv); 445 446 static __init int can_dev_init(void) 447 { 448 int err; 449 450 can_led_notifier_init(); 451 452 err = can_netlink_register(); 453 if (!err) 454 pr_info(MOD_DESC "\n"); 455 456 return err; 457 } 458 module_init(can_dev_init); 459 460 static __exit void can_dev_exit(void) 461 { 462 can_netlink_unregister(); 463 464 can_led_notifier_exit(); 465 } 466 module_exit(can_dev_exit); 467 468 MODULE_ALIAS_RTNL_LINK("can"); 469