drivers/leds/trigger/ledtrig-netdev.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright 2017 Ben Whitten <[email protected]>
   3 // Copyright 2007 Oliver Jowett <[email protected]>
   4 //
   5 // LED Kernel Netdev Trigger
   6 //
   7 // Toggles the LED to reflect the link and traffic state of a named net device
   8 //
   9 // Derived from ledtrig-timer.c which is:
  10 //  Copyright 2005-2006 Openedhand Ltd.
  11 //  Author: Richard Purdie <[email protected]>
  12
  13 #include <linux/atomic.h>
  14 #include <linux/ctype.h>
  15 #include <linux/device.h>
  16 #include <linux/ethtool.h>
  17 #include <linux/init.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/kernel.h>
  20 #include <linux/leds.h>
  21 #include <linux/list.h>
  22 #include <linux/module.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/mutex.h>
  25 #include <linux/rtnetlink.h>
  26 #include <linux/timer.h>
  27 #include "../leds.h"
  28
  29 #define NETDEV_LED_DEFAULT_INTERVAL     50
  30
  31 /*
  32  * Configurable sysfs attributes:
  33  *
  34  * device_name - network device name to monitor
  35  * interval - duration of LED blink, in milliseconds
  36  * link -  LED's normal state reflects whether the link is up
  37  *         (has carrier) or not
  38  * tx -  LED blinks on transmitted data
  39  * rx -  LED blinks on receive data
  40  *
  41  */
  42
  43 struct led_netdev_data {
  44         struct mutex lock;
  45
  46         struct delayed_work work;
  47         struct notifier_block notifier;
  48
  49         struct led_classdev *led_cdev;
  50         struct net_device *net_dev;
  51
  52         char device_name[IFNAMSIZ];
  53         atomic_t interval;
  54         unsigned int last_activity;
  55
  56         unsigned long mode;
  57         int link_speed;
  58         u8 duplex;
  59
  60         bool carrier_link_up;
  61         bool hw_control;
  62 };
  63
  64 static void set_baseline_state(struct led_netdev_data *trigger_data)
  65 {
  66         int current_brightness;
  67         struct led_classdev *led_cdev = trigger_data->led_cdev;
  68
  69         /* Already validated, hw control is possible with the requested mode */
  70         if (trigger_data->hw_control) {
  71                 led_cdev->hw_control_set(led_cdev, trigger_data->mode);
  72
  73                 return;
  74         }
  75
  76         current_brightness = led_cdev->brightness;
  77         if (current_brightness)
  78                 led_cdev->blink_brightness = current_brightness;
  79         if (!led_cdev->blink_brightness)
  80                 led_cdev->blink_brightness = led_cdev->max_brightness;
  81
  82         if (!trigger_data->carrier_link_up) {
  83                 led_set_brightness(led_cdev, LED_OFF);
  84         } else {
  85                 bool blink_on = false;
  86
  87                 if (test_bit(TRIGGER_NETDEV_LINK, &trigger_data->mode))
  88                         blink_on = true;
  89
  90                 if (test_bit(TRIGGER_NETDEV_LINK_10, &trigger_data->mode) &&
  91                     trigger_data->link_speed == SPEED_10)
  92                         blink_on = true;
  93
  94                 if (test_bit(TRIGGER_NETDEV_LINK_100, &trigger_data->mode) &&
  95                     trigger_data->link_speed == SPEED_100)
  96                         blink_on = true;
  97
  98                 if (test_bit(TRIGGER_NETDEV_LINK_1000, &trigger_data->mode) &&
  99                     trigger_data->link_speed == SPEED_1000)
 100                         blink_on = true;
 101
 102                 if (test_bit(TRIGGER_NETDEV_HALF_DUPLEX, &trigger_data->mode) &&
 103                     trigger_data->duplex == DUPLEX_HALF)
 104                         blink_on = true;
 105
 106                 if (test_bit(TRIGGER_NETDEV_FULL_DUPLEX, &trigger_data->mode) &&
 107                     trigger_data->duplex == DUPLEX_FULL)
 108                         blink_on = true;
 109
 110                 if (blink_on)
 111                         led_set_brightness(led_cdev,
 112                                            led_cdev->blink_brightness);
 113                 else
 114                         led_set_brightness(led_cdev, LED_OFF);
 115
 116                 /* If we are looking for RX/TX start periodically
 117                  * checking stats
 118                  */
 119                 if (test_bit(TRIGGER_NETDEV_TX, &trigger_data->mode) ||
 120                     test_bit(TRIGGER_NETDEV_RX, &trigger_data->mode))
 121                         schedule_delayed_work(&trigger_data->work, 0);
 122         }
 123 }
 124
 125 static bool supports_hw_control(struct led_classdev *led_cdev)
 126 {
 127         if (!led_cdev->hw_control_get || !led_cdev->hw_control_set ||
 128             !led_cdev->hw_control_is_supported)
 129                 return false;
 130
 131         return !strcmp(led_cdev->hw_control_trigger, led_cdev->trigger->name);
 132 }
 133
 134 /*
 135  * Validate the configured netdev is the same as the one associated with
 136  * the LED driver in hw control.
 137  */
 138 static bool validate_net_dev(struct led_classdev *led_cdev,
 139                              struct net_device *net_dev)
 140 {
 141         struct device *dev = led_cdev->hw_control_get_device(led_cdev);
 142         struct net_device *ndev;
 143
 144         if (!dev)
 145                 return false;
 146
 147         ndev = to_net_dev(dev);
 148
 149         return ndev == net_dev;
 150 }
 151
 152 static bool can_hw_control(struct led_netdev_data *trigger_data)
 153 {
 154         unsigned long default_interval = msecs_to_jiffies(NETDEV_LED_DEFAULT_INTERVAL);
 155         unsigned int interval = atomic_read(&trigger_data->interval);
 156         struct led_classdev *led_cdev = trigger_data->led_cdev;
 157         int ret;
 158
 159         if (!supports_hw_control(led_cdev))
 160                 return false;
 161
 162         /*
 163          * Interval must be set to the default
 164          * value. Any different value is rejected if in hw
 165          * control.
 166          */
 167         if (interval != default_interval)
 168                 return false;
 169
 170         /*
 171          * net_dev must be set with hw control, otherwise no
 172          * blinking can be happening and there is nothing to
 173          * offloaded. Additionally, for hw control to be
 174          * valid, the configured netdev must be the same as
 175          * netdev associated to the LED.
 176          */
 177         if (!validate_net_dev(led_cdev, trigger_data->net_dev))
 178                 return false;
 179
 180         /* Check if the requested mode is supported */
 181         ret = led_cdev->hw_control_is_supported(led_cdev, trigger_data->mode);
 182         /* Fall back to software blinking if not supported */
 183         if (ret == -EOPNOTSUPP)
 184                 return false;
 185         if (ret) {
 186                 dev_warn(led_cdev->dev,
 187                          "Current mode check failed with error %d\n", ret);
 188                 return false;
 189         }
 190
 191         return true;
 192 }
 193
 194 static void get_device_state(struct led_netdev_data *trigger_data)
 195 {
 196         struct ethtool_link_ksettings cmd;
 197
 198         trigger_data->carrier_link_up = netif_carrier_ok(trigger_data->net_dev);
 199         if (!trigger_data->carrier_link_up)
 200                 return;
 201
 202         if (!__ethtool_get_link_ksettings(trigger_data->net_dev, &cmd)) {
 203                 trigger_data->link_speed = cmd.base.speed;
 204                 trigger_data->duplex = cmd.base.duplex;
 205         }
 206 }
 207
 208 static ssize_t device_name_show(struct device *dev,
 209                                 struct device_attribute *attr, char *buf)
 210 {
 211         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 212         ssize_t len;
 213
 214         mutex_lock(&trigger_data->lock);
 215         len = sprintf(buf, "%s\n", trigger_data->device_name);
 216         mutex_unlock(&trigger_data->lock);
 217
 218         return len;
 219 }
 220
 221 static int set_device_name(struct led_netdev_data *trigger_data,
 222                            const char *name, size_t size)
 223 {
 224         if (size >= IFNAMSIZ)
 225                 return -EINVAL;
 226
 227         cancel_delayed_work_sync(&trigger_data->work);
 228
 229         /*
 230          * Take RTNL lock before trigger_data lock to prevent potential
 231          * deadlock with netdev notifier registration.
 232          */
 233         rtnl_lock();
 234         mutex_lock(&trigger_data->lock);
 235
 236         if (trigger_data->net_dev) {
 237                 dev_put(trigger_data->net_dev);
 238                 trigger_data->net_dev = NULL;
 239         }
 240
 241         memcpy(trigger_data->device_name, name, size);
 242         trigger_data->device_name[size] = 0;
 243         if (size > 0 && trigger_data->device_name[size - 1] == '\n')
 244                 trigger_data->device_name[size - 1] = 0;
 245
 246         if (trigger_data->device_name[0] != 0)
 247                 trigger_data->net_dev =
 248                     dev_get_by_name(&init_net, trigger_data->device_name);
 249
 250         trigger_data->carrier_link_up = false;
 251         trigger_data->link_speed = SPEED_UNKNOWN;
 252         trigger_data->duplex = DUPLEX_UNKNOWN;
 253         if (trigger_data->net_dev)
 254                 get_device_state(trigger_data);
 255
 256         trigger_data->last_activity = 0;
 257
 258         set_baseline_state(trigger_data);
 259         mutex_unlock(&trigger_data->lock);
 260         rtnl_unlock();
 261
 262         return 0;
 263 }
 264
 265 static ssize_t device_name_store(struct device *dev,
 266                                  struct device_attribute *attr, const char *buf,
 267                                  size_t size)
 268 {
 269         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 270         int ret;
 271
 272         ret = set_device_name(trigger_data, buf, size);
 273
 274         if (ret < 0)
 275                 return ret;
 276         return size;
 277 }
 278
 279 static DEVICE_ATTR_RW(device_name);
 280
 281 static ssize_t netdev_led_attr_show(struct device *dev, char *buf,
 282                                     enum led_trigger_netdev_modes attr)
 283 {
 284         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 285         int bit;
 286
 287         switch (attr) {
 288         case TRIGGER_NETDEV_LINK:
 289         case TRIGGER_NETDEV_LINK_10:
 290         case TRIGGER_NETDEV_LINK_100:
 291         case TRIGGER_NETDEV_LINK_1000:
 292         case TRIGGER_NETDEV_HALF_DUPLEX:
 293         case TRIGGER_NETDEV_FULL_DUPLEX:
 294         case TRIGGER_NETDEV_TX:
 295         case TRIGGER_NETDEV_RX:
 296                 bit = attr;
 297                 break;
 298         default:
 299                 return -EINVAL;
 300         }
 301
 302         return sprintf(buf, "%u\n", test_bit(bit, &trigger_data->mode));
 303 }
 304
 305 static ssize_t netdev_led_attr_store(struct device *dev, const char *buf,
 306                                      size_t size, enum led_trigger_netdev_modes attr)
 307 {
 308         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 309         unsigned long state, mode = trigger_data->mode;
 310         int ret;
 311         int bit;
 312
 313         ret = kstrtoul(buf, 0, &state);
 314         if (ret)
 315                 return ret;
 316
 317         switch (attr) {
 318         case TRIGGER_NETDEV_LINK:
 319         case TRIGGER_NETDEV_LINK_10:
 320         case TRIGGER_NETDEV_LINK_100:
 321         case TRIGGER_NETDEV_LINK_1000:
 322         case TRIGGER_NETDEV_HALF_DUPLEX:
 323         case TRIGGER_NETDEV_FULL_DUPLEX:
 324         case TRIGGER_NETDEV_TX:
 325         case TRIGGER_NETDEV_RX:
 326                 bit = attr;
 327                 break;
 328         default:
 329                 return -EINVAL;
 330         }
 331
 332         if (state)
 333                 set_bit(bit, &mode);
 334         else
 335                 clear_bit(bit, &mode);
 336
 337         if (test_bit(TRIGGER_NETDEV_LINK, &mode) &&
 338             (test_bit(TRIGGER_NETDEV_LINK_10, &mode) ||
 339              test_bit(TRIGGER_NETDEV_LINK_100, &mode) ||
 340              test_bit(TRIGGER_NETDEV_LINK_1000, &mode)))
 341                 return -EINVAL;
 342
 343         cancel_delayed_work_sync(&trigger_data->work);
 344
 345         trigger_data->mode = mode;
 346         trigger_data->hw_control = can_hw_control(trigger_data);
 347
 348         set_baseline_state(trigger_data);
 349
 350         return size;
 351 }
 352
 353 #define DEFINE_NETDEV_TRIGGER(trigger_name, trigger) \
 354         static ssize_t trigger_name##_show(struct device *dev, \
 355                 struct device_attribute *attr, char *buf) \
 356         { \
 357                 return netdev_led_attr_show(dev, buf, trigger); \
 358         } \
 359         static ssize_t trigger_name##_store(struct device *dev, \
 360                 struct device_attribute *attr, const char *buf, size_t size) \
 361         { \
 362                 return netdev_led_attr_store(dev, buf, size, trigger); \
 363         } \
 364         static DEVICE_ATTR_RW(trigger_name)
 365
 366 DEFINE_NETDEV_TRIGGER(link, TRIGGER_NETDEV_LINK);
 367 DEFINE_NETDEV_TRIGGER(link_10, TRIGGER_NETDEV_LINK_10);
 368 DEFINE_NETDEV_TRIGGER(link_100, TRIGGER_NETDEV_LINK_100);
 369 DEFINE_NETDEV_TRIGGER(link_1000, TRIGGER_NETDEV_LINK_1000);
 370 DEFINE_NETDEV_TRIGGER(half_duplex, TRIGGER_NETDEV_HALF_DUPLEX);
 371 DEFINE_NETDEV_TRIGGER(full_duplex, TRIGGER_NETDEV_FULL_DUPLEX);
 372 DEFINE_NETDEV_TRIGGER(tx, TRIGGER_NETDEV_TX);
 373 DEFINE_NETDEV_TRIGGER(rx, TRIGGER_NETDEV_RX);
 374
 375 static ssize_t interval_show(struct device *dev,
 376                              struct device_attribute *attr, char *buf)
 377 {
 378         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 379
 380         return sprintf(buf, "%u\n",
 381                        jiffies_to_msecs(atomic_read(&trigger_data->interval)));
 382 }
 383
 384 static ssize_t interval_store(struct device *dev,
 385                               struct device_attribute *attr, const char *buf,
 386                               size_t size)
 387 {
 388         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 389         unsigned long value;
 390         int ret;
 391
 392         if (trigger_data->hw_control)
 393                 return -EINVAL;
 394
 395         ret = kstrtoul(buf, 0, &value);
 396         if (ret)
 397                 return ret;
 398
 399         /* impose some basic bounds on the timer interval */
 400         if (value >= 5 && value <= 10000) {
 401                 cancel_delayed_work_sync(&trigger_data->work);
 402
 403                 atomic_set(&trigger_data->interval, msecs_to_jiffies(value));
 404                 set_baseline_state(trigger_data);       /* resets timer */
 405         }
 406
 407         return size;
 408 }
 409
 410 static DEVICE_ATTR_RW(interval);
 411
 412 static ssize_t offloaded_show(struct device *dev,
 413                               struct device_attribute *attr, char *buf)
 414 {
 415         struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
 416
 417         return sprintf(buf, "%d\n", trigger_data->hw_control);
 418 }
 419
 420 static DEVICE_ATTR_RO(offloaded);
 421
 422 static struct attribute *netdev_trig_attrs[] = {
 423         &dev_attr_device_name.attr,
 424         &dev_attr_link.attr,
 425         &dev_attr_link_10.attr,
 426         &dev_attr_link_100.attr,
 427         &dev_attr_link_1000.attr,
 428         &dev_attr_full_duplex.attr,
 429         &dev_attr_half_duplex.attr,
 430         &dev_attr_rx.attr,
 431         &dev_attr_tx.attr,
 432         &dev_attr_interval.attr,
 433         &dev_attr_offloaded.attr,
 434         NULL
 435 };
 436 ATTRIBUTE_GROUPS(netdev_trig);
 437
 438 static int netdev_trig_notify(struct notifier_block *nb,
 439                               unsigned long evt, void *dv)
 440 {
 441         struct net_device *dev =
 442                 netdev_notifier_info_to_dev((struct netdev_notifier_info *)dv);
 443         struct led_netdev_data *trigger_data =
 444                 container_of(nb, struct led_netdev_data, notifier);
 445
 446         if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
 447             && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER
 448             && evt != NETDEV_CHANGENAME)
 449                 return NOTIFY_DONE;
 450
 451         if (!(dev == trigger_data->net_dev ||
 452               (evt == NETDEV_CHANGENAME && !strcmp(dev->name, trigger_data->device_name)) ||
 453               (evt == NETDEV_REGISTER && !strcmp(dev->name, trigger_data->device_name))))
 454                 return NOTIFY_DONE;
 455
 456         cancel_delayed_work_sync(&trigger_data->work);
 457
 458         mutex_lock(&trigger_data->lock);
 459
 460         trigger_data->carrier_link_up = false;
 461         trigger_data->link_speed = SPEED_UNKNOWN;
 462         trigger_data->duplex = DUPLEX_UNKNOWN;
 463         switch (evt) {
 464         case NETDEV_CHANGENAME:
 465                 get_device_state(trigger_data);
 466                 fallthrough;
 467         case NETDEV_REGISTER:
 468                 dev_put(trigger_data->net_dev);
 469                 dev_hold(dev);
 470                 trigger_data->net_dev = dev;
 471                 break;
 472         case NETDEV_UNREGISTER:
 473                 dev_put(trigger_data->net_dev);
 474                 trigger_data->net_dev = NULL;
 475                 break;
 476         case NETDEV_UP:
 477         case NETDEV_CHANGE:
 478                 get_device_state(trigger_data);
 479                 break;
 480         }
 481
 482         set_baseline_state(trigger_data);
 483
 484         mutex_unlock(&trigger_data->lock);
 485
 486         return NOTIFY_DONE;
 487 }
 488
 489 /* here's the real work! */
 490 static void netdev_trig_work(struct work_struct *work)
 491 {
 492         struct led_netdev_data *trigger_data =
 493                 container_of(work, struct led_netdev_data, work.work);
 494         struct rtnl_link_stats64 *dev_stats;
 495         unsigned int new_activity;
 496         struct rtnl_link_stats64 temp;
 497         unsigned long interval;
 498         int invert;
 499
 500         /* If we dont have a device, insure we are off */
 501         if (!trigger_data->net_dev) {
 502                 led_set_brightness(trigger_data->led_cdev, LED_OFF);
 503                 return;
 504         }
 505
 506         /* If we are not looking for RX/TX then return  */
 507         if (!test_bit(TRIGGER_NETDEV_TX, &trigger_data->mode) &&
 508             !test_bit(TRIGGER_NETDEV_RX, &trigger_data->mode))
 509                 return;
 510
 511         dev_stats = dev_get_stats(trigger_data->net_dev, &temp);
 512         new_activity =
 513             (test_bit(TRIGGER_NETDEV_TX, &trigger_data->mode) ?
 514                 dev_stats->tx_packets : 0) +
 515             (test_bit(TRIGGER_NETDEV_RX, &trigger_data->mode) ?
 516                 dev_stats->rx_packets : 0);
 517
 518         if (trigger_data->last_activity != new_activity) {
 519                 led_stop_software_blink(trigger_data->led_cdev);
 520
 521                 invert = test_bit(TRIGGER_NETDEV_LINK, &trigger_data->mode) ||
 522                          test_bit(TRIGGER_NETDEV_LINK_10, &trigger_data->mode) ||
 523                          test_bit(TRIGGER_NETDEV_LINK_100, &trigger_data->mode) ||
 524                          test_bit(TRIGGER_NETDEV_LINK_1000, &trigger_data->mode) ||
 525                          test_bit(TRIGGER_NETDEV_HALF_DUPLEX, &trigger_data->mode) ||
 526                          test_bit(TRIGGER_NETDEV_FULL_DUPLEX, &trigger_data->mode);
 527                 interval = jiffies_to_msecs(
 528                                 atomic_read(&trigger_data->interval));
 529                 /* base state is ON (link present) */
 530                 led_blink_set_oneshot(trigger_data->led_cdev,
 531                                       &interval,
 532                                       &interval,
 533                                       invert);
 534                 trigger_data->last_activity = new_activity;
 535         }
 536
 537         schedule_delayed_work(&trigger_data->work,
 538                         (atomic_read(&trigger_data->interval)*2));
 539 }
 540
 541 static int netdev_trig_activate(struct led_classdev *led_cdev)
 542 {
 543         struct led_netdev_data *trigger_data;
 544         unsigned long mode = 0;
 545         struct device *dev;
 546         int rc;
 547
 548         trigger_data = kzalloc(sizeof(struct led_netdev_data), GFP_KERNEL);
 549         if (!trigger_data)
 550                 return -ENOMEM;
 551
 552         mutex_init(&trigger_data->lock);
 553
 554         trigger_data->notifier.notifier_call = netdev_trig_notify;
 555         trigger_data->notifier.priority = 10;
 556
 557         INIT_DELAYED_WORK(&trigger_data->work, netdev_trig_work);
 558
 559         trigger_data->led_cdev = led_cdev;
 560         trigger_data->net_dev = NULL;
 561         trigger_data->device_name[0] = 0;
 562
 563         trigger_data->mode = 0;
 564         atomic_set(&trigger_data->interval, msecs_to_jiffies(NETDEV_LED_DEFAULT_INTERVAL));
 565         trigger_data->last_activity = 0;
 566
 567         /* Check if hw control is active by default on the LED.
 568          * Init already enabled mode in hw control.
 569          */
 570         if (supports_hw_control(led_cdev)) {
 571                 dev = led_cdev->hw_control_get_device(led_cdev);
 572                 if (dev) {
 573                         const char *name = dev_name(dev);
 574
 575                         set_device_name(trigger_data, name, strlen(name));
 576                         trigger_data->hw_control = true;
 577
 578                         rc = led_cdev->hw_control_get(led_cdev, &mode);
 579                         if (!rc)
 580                                 trigger_data->mode = mode;
 581                 }
 582         }
 583
 584         led_set_trigger_data(led_cdev, trigger_data);
 585
 586         rc = register_netdevice_notifier(&trigger_data->notifier);
 587         if (rc)
 588                 kfree(trigger_data);
 589
 590         return rc;
 591 }
 592
 593 static void netdev_trig_deactivate(struct led_classdev *led_cdev)
 594 {
 595         struct led_netdev_data *trigger_data = led_get_trigger_data(led_cdev);
 596
 597         unregister_netdevice_notifier(&trigger_data->notifier);
 598
 599         cancel_delayed_work_sync(&trigger_data->work);
 600
 601         led_set_brightness(led_cdev, LED_OFF);
 602
 603         dev_put(trigger_data->net_dev);
 604
 605         kfree(trigger_data);
 606 }
 607
 608 static struct led_trigger netdev_led_trigger = {
 609         .name = "netdev",
 610         .activate = netdev_trig_activate,
 611         .deactivate = netdev_trig_deactivate,
 612         .groups = netdev_trig_groups,
 613 };
 614
 615 module_led_trigger(netdev_led_trigger);
 616
 617 MODULE_AUTHOR("Ben Whitten <[email protected]>");
 618 MODULE_AUTHOR("Oliver Jowett <[email protected]>");
 619 MODULE_DESCRIPTION("Netdev LED trigger");
 620 MODULE_LICENSE("GPL v2");