leds: trigger: Introduce a NETDEV trigger

This commit introduces a NETDEV trigger for named device
activity. Available triggers are link, rx, and tx.

Signed-off-by: Ben Whitten <ben.whitten@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

3 files changed, 504 insertions, 0 deletions

diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index 6dac48c457d1..a2559b4fdfff 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -135,4 +135,11 @@ config LEDS_TRIGGER_PANIC
           a different trigger.
           If unsure, say Y.
 
+config LEDS_TRIGGER_NETDEV
+        tristate "LED Netdev Trigger"
+        depends on NET && LEDS_TRIGGERS
+        help
+          This allows LEDs to be controlled by network device activity.
+          If unsure, say Y.
+
 endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index 4a8b6cff7761..f3cfe1950538 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON)	+= ledtrig-default-on.o
 obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT)    += ledtrig-transient.o
 obj-$(CONFIG_LEDS_TRIGGER_CAMERA)       += ledtrig-camera.o
 obj-$(CONFIG_LEDS_TRIGGER_PANIC)        += ledtrig-panic.o
+obj-$(CONFIG_LEDS_TRIGGER_NETDEV)       += ledtrig-netdev.o
diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c
new file mode 100644
index 000000000000..6df4781a6308
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-netdev.c
@@ -0,0 +1,496 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright 2017 Ben Whitten <ben.whitten@gmail.com>
+// Copyright 2007 Oliver Jowett <oliver@opencloud.com>
+//
+// LED Kernel Netdev Trigger
+//
+// Toggles the LED to reflect the link and traffic state of a named net device
+//
+// Derived from ledtrig-timer.c which is:
+//  Copyright 2005-2006 Openedhand Ltd.
+//  Author: Richard Purdie <rpurdie@openedhand.com>
+
+#include <linux/atomic.h>
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include "../leds.h"
+
+/*
+ * Configurable sysfs attributes:
+ *
+ * device_name - network device name to monitor
+ * interval - duration of LED blink, in milliseconds
+ * link -  LED's normal state reflects whether the link is up
+ *         (has carrier) or not
+ * tx -  LED blinks on transmitted data
+ * rx -  LED blinks on receive data
+ *
+ */
+
+struct led_netdev_data {
+        spinlock_t lock;
+
+        struct delayed_work work;
+        struct notifier_block notifier;
+
+        struct led_classdev *led_cdev;
+        struct net_device *net_dev;
+
+        char device_name[IFNAMSIZ];
+        atomic_t interval;
+        unsigned int last_activity;
+
+        unsigned long mode;
+#define NETDEV_LED_LINK 0
+#define NETDEV_LED_TX   1
+#define NETDEV_LED_RX   2
+#define NETDEV_LED_MODE_LINKUP  3
+};
+
+enum netdev_led_attr {
+        NETDEV_ATTR_LINK,
+        NETDEV_ATTR_TX,
+        NETDEV_ATTR_RX
+};
+
+static void set_baseline_state(struct led_netdev_data *trigger_data)
+{
+        int current_brightness;
+        struct led_classdev *led_cdev = trigger_data->led_cdev;
+
+        current_brightness = led_cdev->brightness;
+        if (current_brightness)
+                led_cdev->blink_brightness = current_brightness;
+        if (!led_cdev->blink_brightness)
+                led_cdev->blink_brightness = led_cdev->max_brightness;
+
+        if (!test_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode))
+                led_set_brightness(led_cdev, LED_OFF);
+        else {
+                if (test_bit(NETDEV_LED_LINK, &trigger_data->mode))
+                        led_set_brightness(led_cdev,
+                                           led_cdev->blink_brightness);
+                else
+                        led_set_brightness(led_cdev, LED_OFF);
+
+                /* If we are looking for RX/TX start periodically
+                 * checking stats
+                 */
+                if (test_bit(NETDEV_LED_TX, &trigger_data->mode) ||
+                    test_bit(NETDEV_LED_RX, &trigger_data->mode))
+                        schedule_delayed_work(&trigger_data->work, 0);
+        }
+}
+
+static ssize_t device_name_show(struct device *dev,
+                                struct device_attribute *attr, char *buf)
+{
+        struct led_classdev *led_cdev = dev_get_drvdata(dev);
+        struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+        ssize_t len;
+
+        spin_lock_bh(&trigger_data->lock);
+        len = sprintf(buf, "%s\n", trigger_data->device_name);
+        spin_unlock_bh(&trigger_data->lock);
+
+        return len;
+}
+
+static ssize_t device_name_store(struct device *dev,
+                                 struct device_attribute *attr, const char *buf,
+                                 size_t size)
+{
+        struct led_classdev *led_cdev = dev_get_drvdata(dev);
+        struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+
+        if (size >= IFNAMSIZ)
+                return -EINVAL;
+
+        cancel_delayed_work_sync(&trigger_data->work);
+
+        spin_lock_bh(&trigger_data->lock);
+
+        if (trigger_data->net_dev) {
+                dev_put(trigger_data->net_dev);
+                trigger_data->net_dev = NULL;
+        }
+
+        strncpy(trigger_data->device_name, buf, size);
+        if (size > 0 && trigger_data->device_name[size - 1] == '\n')
+                trigger_data->device_name[size - 1] = 0;
+
+        if (trigger_data->device_name[0] != 0)
+                trigger_data->net_dev =
+                    dev_get_by_name(&init_net, trigger_data->device_name);
+
+        clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
+        if (trigger_data->net_dev != NULL)
+                if (netif_carrier_ok(trigger_data->net_dev))
+                        set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
+
+        trigger_data->last_activity = 0;
+
+        set_baseline_state(trigger_data);
+        spin_unlock_bh(&trigger_data->lock);
+
+        return size;
+}
+
+static DEVICE_ATTR_RW(device_name);
+
+static ssize_t netdev_led_attr_show(struct device *dev, char *buf,
+        enum netdev_led_attr attr)
+{
+        struct led_classdev *led_cdev = dev_get_drvdata(dev);
+        struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+        int bit;
+
+        switch (attr) {
+        case NETDEV_ATTR_LINK:
+                bit = NETDEV_LED_LINK;
+                break;
+        case NETDEV_ATTR_TX:
+                bit = NETDEV_LED_TX;
+                break;
+        case NETDEV_ATTR_RX:
+                bit = NETDEV_LED_RX;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        return sprintf(buf, "%u\n", test_bit(bit, &trigger_data->mode));
+}
+
+static ssize_t netdev_led_attr_store(struct device *dev, const char *buf,
+        size_t size, enum netdev_led_attr attr)
+{
+        struct led_classdev *led_cdev = dev_get_drvdata(dev);
+        struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+        unsigned long state;
+        int ret;
+        int bit;
+
+        ret = kstrtoul(buf, 0, &state);
+        if (ret)
+                return ret;
+
+        switch (attr) {
+        case NETDEV_ATTR_LINK:
+                bit = NETDEV_LED_LINK;
+                break;
+        case NETDEV_ATTR_TX:
+                bit = NETDEV_LED_TX;
+                break;
+        case NETDEV_ATTR_RX:
+                bit = NETDEV_LED_RX;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        cancel_delayed_work_sync(&trigger_data->work);
+
+        if (state)
+                set_bit(bit, &trigger_data->mode);
+        else
+                clear_bit(bit, &trigger_data->mode);
+
+        set_baseline_state(trigger_data);
+
+        return size;
+}
+
+static ssize_t link_show(struct device *dev,
+        struct device_attribute *attr, char *buf)
+{
+        return netdev_led_attr_show(dev, buf, NETDEV_ATTR_LINK);
+}
+
+static ssize_t link_store(struct device *dev,
+        struct device_attribute *attr, const char *buf, size_t size)
+{
+        return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_LINK);
+}
+
+static DEVICE_ATTR_RW(link);
+
+static ssize_t tx_show(struct device *dev,
+        struct device_attribute *attr, char *buf)
+{
+        return netdev_led_attr_show(dev, buf, NETDEV_ATTR_TX);
+}
+
+static ssize_t tx_store(struct device *dev,
+        struct device_attribute *attr, const char *buf, size_t size)
+{
+        return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_TX);
+}
+
+static DEVICE_ATTR_RW(tx);
+
+static ssize_t rx_show(struct device *dev,
+        struct device_attribute *attr, char *buf)
+{
+        return netdev_led_attr_show(dev, buf, NETDEV_ATTR_RX);
+}
+
+static ssize_t rx_store(struct device *dev,
+        struct device_attribute *attr, const char *buf, size_t size)
+{
+        return netdev_led_attr_store(dev, buf, size, NETDEV_ATTR_RX);
+}
+
+static DEVICE_ATTR_RW(rx);
+
+static ssize_t interval_show(struct device *dev,
+                             struct device_attribute *attr, char *buf)
+{
+        struct led_classdev *led_cdev = dev_get_drvdata(dev);
+        struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+
+        return sprintf(buf, "%u\n",
+                       jiffies_to_msecs(atomic_read(&trigger_data->interval)));
+}
+
+static ssize_t interval_store(struct device *dev,
+                              struct device_attribute *attr, const char *buf,
+                              size_t size)
+{
+        struct led_classdev *led_cdev = dev_get_drvdata(dev);
+        struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+        unsigned long value;
+        int ret;
+
+        ret = kstrtoul(buf, 0, &value);
+        if (ret)
+                return ret;
+
+        /* impose some basic bounds on the timer interval */
+        if (value >= 5 && value <= 10000) {
+                cancel_delayed_work_sync(&trigger_data->work);
+
+                atomic_set(&trigger_data->interval, msecs_to_jiffies(value));
+                set_baseline_state(trigger_data);       /* resets timer */
+        }
+
+        return size;
+}
+
+static DEVICE_ATTR_RW(interval);
+
+static int netdev_trig_notify(struct notifier_block *nb,
+                              unsigned long evt, void *dv)
+{
+        struct net_device *dev =
+                netdev_notifier_info_to_dev((struct netdev_notifier_info *)dv);
+        struct led_netdev_data *trigger_data = container_of(nb,
+                                                            struct
+                                                            led_netdev_data,
+                                                            notifier);
+
+        if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
+            && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER
+            && evt != NETDEV_CHANGENAME)
+                return NOTIFY_DONE;
+
+        if (strcmp(dev->name, trigger_data->device_name))
+                return NOTIFY_DONE;
+
+        cancel_delayed_work_sync(&trigger_data->work);
+
+        spin_lock_bh(&trigger_data->lock);
+
+        clear_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
+        switch (evt) {
+        case NETDEV_REGISTER:
+                if (trigger_data->net_dev)
+                        dev_put(trigger_data->net_dev);
+                dev_hold(dev);
+                trigger_data->net_dev = dev;
+                break;
+        case NETDEV_CHANGENAME:
+        case NETDEV_UNREGISTER:
+                if (trigger_data->net_dev) {
+                        dev_put(trigger_data->net_dev);
+                        trigger_data->net_dev = NULL;
+                }
+                break;
+        case NETDEV_UP:
+        case NETDEV_CHANGE:
+                if (netif_carrier_ok(dev))
+                        set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);
+                break;
+        }
+
+        set_baseline_state(trigger_data);
+
+        spin_unlock_bh(&trigger_data->lock);
+
+        return NOTIFY_DONE;
+}
+
+/* here's the real work! */
+static void netdev_trig_work(struct work_struct *work)
+{
+        struct led_netdev_data *trigger_data = container_of(work,
+                                                            struct
+                                                            led_netdev_data,
+                                                            work.work);
+        struct rtnl_link_stats64 *dev_stats;
+        unsigned int new_activity;
+        struct rtnl_link_stats64 temp;
+        unsigned long interval;
+        int invert;
+
+        /* If we dont have a device, insure we are off */
+        if (!trigger_data->net_dev) {
+                led_set_brightness(trigger_data->led_cdev, LED_OFF);
+                return;
+        }
+
+        /* If we are not looking for RX/TX then return  */
+        if (!test_bit(NETDEV_LED_TX, &trigger_data->mode) &&
+            !test_bit(NETDEV_LED_RX, &trigger_data->mode))
+                return;
+
+        dev_stats = dev_get_stats(trigger_data->net_dev, &temp);
+        new_activity =
+            (test_bit(NETDEV_LED_TX, &trigger_data->mode) ?
+                dev_stats->tx_packets : 0) +
+            (test_bit(NETDEV_LED_RX, &trigger_data->mode) ?
+                dev_stats->rx_packets : 0);
+
+        if (trigger_data->last_activity != new_activity) {
+                led_stop_software_blink(trigger_data->led_cdev);
+
+                invert = test_bit(NETDEV_LED_LINK, &trigger_data->mode);
+                interval = jiffies_to_msecs(
+                                atomic_read(&trigger_data->interval));
+                /* base state is ON (link present) */
+                led_blink_set_oneshot(trigger_data->led_cdev,
+                                      &interval,
+                                      &interval,
+                                      invert);
+                trigger_data->last_activity = new_activity;
+        }
+
+        schedule_delayed_work(&trigger_data->work,
+                        (atomic_read(&trigger_data->interval)*2));
+}
+
+static void netdev_trig_activate(struct led_classdev *led_cdev)
+{
+        struct led_netdev_data *trigger_data;
+        int rc;
+
+        trigger_data = kzalloc(sizeof(struct led_netdev_data), GFP_KERNEL);
+        if (!trigger_data)
+                return;
+
+        spin_lock_init(&trigger_data->lock);
+
+        trigger_data->notifier.notifier_call = netdev_trig_notify;
+        trigger_data->notifier.priority = 10;
+
+        INIT_DELAYED_WORK(&trigger_data->work, netdev_trig_work);
+
+        trigger_data->led_cdev = led_cdev;
+        trigger_data->net_dev = NULL;
+        trigger_data->device_name[0] = 0;
+
+        trigger_data->mode = 0;
+        atomic_set(&trigger_data->interval, msecs_to_jiffies(50));
+        trigger_data->last_activity = 0;
+
+        led_cdev->trigger_data = trigger_data;
+
+        rc = device_create_file(led_cdev->dev, &dev_attr_device_name);
+        if (rc)
+                goto err_out;
+        rc = device_create_file(led_cdev->dev, &dev_attr_link);
+        if (rc)
+                goto err_out_device_name;
+        rc = device_create_file(led_cdev->dev, &dev_attr_rx);
+        if (rc)
+                goto err_out_link;
+        rc = device_create_file(led_cdev->dev, &dev_attr_tx);
+        if (rc)
+                goto err_out_rx;
+        rc = device_create_file(led_cdev->dev, &dev_attr_interval);
+        if (rc)
+                goto err_out_tx;
+        rc = register_netdevice_notifier(&trigger_data->notifier);
+        if (rc)
+                goto err_out_interval;
+        return;
+
+err_out_interval:
+        device_remove_file(led_cdev->dev, &dev_attr_interval);
+err_out_tx:
+        device_remove_file(led_cdev->dev, &dev_attr_tx);
+err_out_rx:
+        device_remove_file(led_cdev->dev, &dev_attr_rx);
+err_out_link:
+        device_remove_file(led_cdev->dev, &dev_attr_link);
+err_out_device_name:
+        device_remove_file(led_cdev->dev, &dev_attr_device_name);
+err_out:
+        led_cdev->trigger_data = NULL;
+        kfree(trigger_data);
+}
+
+static void netdev_trig_deactivate(struct led_classdev *led_cdev)
+{
+        struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+
+        if (trigger_data) {
+                unregister_netdevice_notifier(&trigger_data->notifier);
+
+                device_remove_file(led_cdev->dev, &dev_attr_device_name);
+                device_remove_file(led_cdev->dev, &dev_attr_link);
+                device_remove_file(led_cdev->dev, &dev_attr_rx);
+                device_remove_file(led_cdev->dev, &dev_attr_tx);
+                device_remove_file(led_cdev->dev, &dev_attr_interval);
+
+                cancel_delayed_work_sync(&trigger_data->work);
+
+                if (trigger_data->net_dev)
+                        dev_put(trigger_data->net_dev);
+
+                kfree(trigger_data);
+        }
+}
+
+static struct led_trigger netdev_led_trigger = {
+        .name = "netdev",
+        .activate = netdev_trig_activate,
+        .deactivate = netdev_trig_deactivate,
+};
+
+static int __init netdev_trig_init(void)
+{
+        return led_trigger_register(&netdev_led_trigger);
+}
+
+static void __exit netdev_trig_exit(void)
+{
+        led_trigger_unregister(&netdev_led_trigger);
+}
+
+module_init(netdev_trig_init);
+module_exit(netdev_trig_exit);
+
+MODULE_AUTHOR("Ben Whitten <ben.whitten@gmail.com>");
+MODULE_AUTHOR("Oliver Jowett <oliver@opencloud.com>");
+MODULE_DESCRIPTION("Netdev LED trigger");
+MODULE_LICENSE("GPL v2");