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 can_ml_priv *can_ml; 243 struct net_device *dev; 244 struct can_priv *priv; 245 int size; 246 247 /* We put the driver's priv, the CAN mid layer priv and the 248 * echo skb into the netdevice's priv. The memory layout for 249 * the netdev_priv is like this: 250 * 251 * +-------------------------+ 252 * | driver's priv | 253 * +-------------------------+ 254 * | struct can_ml_priv | 255 * +-------------------------+ 256 * | array of struct sk_buff | 257 * +-------------------------+ 258 */ 259 260 size = ALIGN(sizeof_priv, NETDEV_ALIGN) + sizeof(struct can_ml_priv); 261 262 if (echo_skb_max) 263 size = ALIGN(size, sizeof(struct sk_buff *)) + 264 echo_skb_max * sizeof(struct sk_buff *); 265 266 dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup, 267 txqs, rxqs); 268 if (!dev) 269 return NULL; 270 271 priv = netdev_priv(dev); 272 priv->dev = dev; 273 274 can_ml = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN); 275 can_set_ml_priv(dev, can_ml); 276 277 if (echo_skb_max) { 278 priv->echo_skb_max = echo_skb_max; 279 priv->echo_skb = (void *)priv + 280 (size - echo_skb_max * sizeof(struct sk_buff *)); 281 } 282 283 priv->state = CAN_STATE_STOPPED; 284 285 INIT_DELAYED_WORK(&priv->restart_work, can_restart_work); 286 287 return dev; 288 } 289 EXPORT_SYMBOL_GPL(alloc_candev_mqs); 290 291 /* Free space of the CAN network device */ 292 void free_candev(struct net_device *dev) 293 { 294 free_netdev(dev); 295 } 296 EXPORT_SYMBOL_GPL(free_candev); 297 298 /* changing MTU and control mode for CAN/CANFD devices */ 299 int can_change_mtu(struct net_device *dev, int new_mtu) 300 { 301 struct can_priv *priv = netdev_priv(dev); 302 303 /* Do not allow changing the MTU while running */ 304 if (dev->flags & IFF_UP) 305 return -EBUSY; 306 307 /* allow change of MTU according to the CANFD ability of the device */ 308 switch (new_mtu) { 309 case CAN_MTU: 310 /* 'CANFD-only' controllers can not switch to CAN_MTU */ 311 if (priv->ctrlmode_static & CAN_CTRLMODE_FD) 312 return -EINVAL; 313 314 priv->ctrlmode &= ~CAN_CTRLMODE_FD; 315 break; 316 317 case CANFD_MTU: 318 /* check for potential CANFD ability */ 319 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) && 320 !(priv->ctrlmode_static & CAN_CTRLMODE_FD)) 321 return -EINVAL; 322 323 priv->ctrlmode |= CAN_CTRLMODE_FD; 324 break; 325 326 default: 327 return -EINVAL; 328 } 329 330 dev->mtu = new_mtu; 331 return 0; 332 } 333 EXPORT_SYMBOL_GPL(can_change_mtu); 334 335 /* Common open function when the device gets opened. 336 * 337 * This function should be called in the open function of the device 338 * driver. 339 */ 340 int open_candev(struct net_device *dev) 341 { 342 struct can_priv *priv = netdev_priv(dev); 343 344 if (!priv->bittiming.bitrate) { 345 netdev_err(dev, "bit-timing not yet defined\n"); 346 return -EINVAL; 347 } 348 349 /* For CAN FD the data bitrate has to be >= the arbitration bitrate */ 350 if ((priv->ctrlmode & CAN_CTRLMODE_FD) && 351 (!priv->data_bittiming.bitrate || 352 priv->data_bittiming.bitrate < priv->bittiming.bitrate)) { 353 netdev_err(dev, "incorrect/missing data bit-timing\n"); 354 return -EINVAL; 355 } 356 357 /* Switch carrier on if device was stopped while in bus-off state */ 358 if (!netif_carrier_ok(dev)) 359 netif_carrier_on(dev); 360 361 return 0; 362 } 363 EXPORT_SYMBOL_GPL(open_candev); 364 365 #ifdef CONFIG_OF 366 /* Common function that can be used to understand the limitation of 367 * a transceiver when it provides no means to determine these limitations 368 * at runtime. 369 */ 370 void of_can_transceiver(struct net_device *dev) 371 { 372 struct device_node *dn; 373 struct can_priv *priv = netdev_priv(dev); 374 struct device_node *np = dev->dev.parent->of_node; 375 int ret; 376 377 dn = of_get_child_by_name(np, "can-transceiver"); 378 if (!dn) 379 return; 380 381 ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max); 382 of_node_put(dn); 383 if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max)) 384 netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n"); 385 } 386 EXPORT_SYMBOL_GPL(of_can_transceiver); 387 #endif 388 389 /* Common close function for cleanup before the device gets closed. 390 * 391 * This function should be called in the close function of the device 392 * driver. 393 */ 394 void close_candev(struct net_device *dev) 395 { 396 struct can_priv *priv = netdev_priv(dev); 397 398 cancel_delayed_work_sync(&priv->restart_work); 399 can_flush_echo_skb(dev); 400 } 401 EXPORT_SYMBOL_GPL(close_candev); 402 403 /* Register the CAN network device */ 404 int register_candev(struct net_device *dev) 405 { 406 struct can_priv *priv = netdev_priv(dev); 407 408 /* Ensure termination_const, termination_const_cnt and 409 * do_set_termination consistency. All must be either set or 410 * unset. 411 */ 412 if ((!priv->termination_const != !priv->termination_const_cnt) || 413 (!priv->termination_const != !priv->do_set_termination)) 414 return -EINVAL; 415 416 if (!priv->bitrate_const != !priv->bitrate_const_cnt) 417 return -EINVAL; 418 419 if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt) 420 return -EINVAL; 421 422 dev->rtnl_link_ops = &can_link_ops; 423 netif_carrier_off(dev); 424 425 return register_netdev(dev); 426 } 427 EXPORT_SYMBOL_GPL(register_candev); 428 429 /* Unregister the CAN network device */ 430 void unregister_candev(struct net_device *dev) 431 { 432 unregister_netdev(dev); 433 } 434 EXPORT_SYMBOL_GPL(unregister_candev); 435 436 /* Test if a network device is a candev based device 437 * and return the can_priv* if so. 438 */ 439 struct can_priv *safe_candev_priv(struct net_device *dev) 440 { 441 if (dev->type != ARPHRD_CAN || dev->rtnl_link_ops != &can_link_ops) 442 return NULL; 443 444 return netdev_priv(dev); 445 } 446 EXPORT_SYMBOL_GPL(safe_candev_priv); 447 448 static __init int can_dev_init(void) 449 { 450 int err; 451 452 can_led_notifier_init(); 453 454 err = can_netlink_register(); 455 if (!err) 456 pr_info(MOD_DESC "\n"); 457 458 return err; 459 } 460 module_init(can_dev_init); 461 462 static __exit void can_dev_exit(void) 463 { 464 can_netlink_unregister(); 465 466 can_led_notifier_exit(); 467 } 468 module_exit(can_dev_exit); 469 470 MODULE_ALIAS_RTNL_LINK("can"); 471