Message-Id: <1290998056-8310-1-git-send-email-ecc@cmu.edu>
Date:	Sun, 28 Nov 2010 21:34:16 -0500
From:	Eric Cooper <ecc@....edu>
To:	linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
	Richard Purdie <rpurdie@...ys.net>,
	Randy Dunlap <rdunlap@...otime.net>
Cc:	Eric Cooper <ecc@....edu>
Subject: [PATCH v2] add netdev led trigger

Add a netdev LED trigger for all Blinkenlights lovers...
Originally taken from https://dev.openwrt.org/ticket/2776
Slightly updated for 2.6.24 by Mickey Lauer <mickey@...nmoko.org>
and for 2.6.36 by Eric Cooper <ecc@....edu>

Signed-off-by: Eric Cooper <ecc@....edu>
---
Changes in v2:
- Use individual entries for link, transmit, and receive;
  each can be "enabled" or "disabled"
- Use strict_strtoul instead of simple_strtoul
- Add descriptions to Documentation/ABI/testing/sysfs-class-led

 Documentation/ABI/testing/sysfs-class-led |   64 ++++
 drivers/leds/Kconfig                      |    7 +
 drivers/leds/Makefile                     |    1 +
 drivers/leds/ledtrig-netdev.c             |  475 +++++++++++++++++++++++++++++
 4 files changed, 547 insertions(+), 0 deletions(-)
 create mode 100644 drivers/leds/ledtrig-netdev.c

diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led
index 9e4541d..0b03863 100644
--- a/Documentation/ABI/testing/sysfs-class-led
+++ b/Documentation/ABI/testing/sysfs-class-led
@@ -26,3 +26,67 @@ Description:
 		scheduler is chosen. Trigger specific parameters can appear in
 		/sys/class/leds/<led> once a given trigger is selected.
 
+What:		/sys/class/leds/<led>/device_name
+Date:		November 2010
+KernelVersion:	2.6.37
+Contact:	Eric Cooper <ecc@....edu>
+Description:
+		Network device name to monitor when trigger is set to "netdev".
+
+What:		/sys/class/leds/<led>/interval
+Date:		November 2010
+KernelVersion:	2.6.37
+Contact:	Eric Cooper <ecc@....edu>
+Description:
+		Duration of LED blink in milliseconds when trigger is set to
+		"netdev".
+
+What:		/sys/class/leds/<led>/link
+Date:		November 2010
+KernelVersion:	2.6.37
+Contact:	Eric Cooper <ecc@....edu>
+Description:
+		When trigger is set to "netdev", this value is either "enabled"
+		or "disabled". If enabled, this LED's normal state reflects
+		whether or not the link for the corresponding network device
+		is up (has carrier).
+
+What:		/sys/class/leds/<led>/transmit
+Date:		November 2010
+KernelVersion:	2.6.37
+Contact:	Eric Cooper <ecc@....edu>
+Description:
+		When trigger is set to "netdev", this value is either "enabled"
+		or "disabled". If enabled, this LED blinks when data is
+		transmitted on the corresponding network device.
+
+What:		/sys/class/leds/<led>/receive
+Date:		November 2010
+KernelVersion:	2.6.37
+Contact:	Eric Cooper <ecc@....edu>
+Description:
+		When trigger is set to "netdev", this value is either "enabled"
+		or "disabled". If enabled, this LED blinks when data is
+		received on the corresponding network device.
+
+		Example configurations:
+
+		Simple link status LED:
+		# echo netdev >someled/trigger
+		# echo eth0 >someled/device_name
+		# echo enabled >someled/link
+
+		Ethernet-style link/activity LED:
+		# echo netdev >someled/trigger
+		# echo eth0 >someled/device_name
+		# echo enabled >someled/link
+		# echo enabled >someled/transmit
+		# echo enabled >someled/receive
+
+		Modem-style tx/rx LEDs:
+		# echo netdev >led1/trigger
+		# echo ppp0 >led1/device_name
+		# echo enabled >led1/transmit
+		# echo netdev >led2/trigger
+		# echo ppp0 >led2/device_name
+		# echo enabled >led2/receive
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 77b8fd2..8d81cd0 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -374,6 +374,13 @@ config LEDS_TRIGGER_HEARTBEAT
 	  load average.
 	  If unsure, say Y.
 
+config LEDS_TRIGGER_NETDEV
+	tristate "LED Network Device Trigger"
+	depends on NET
+	help
+	  This allows LEDs to be controlled by network device activity.
+	  If unsure, say Y.
+
 config LEDS_TRIGGER_BACKLIGHT
 	tristate "LED backlight Trigger"
 	help
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index aae6989..a3bb67d 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -49,6 +49,7 @@ obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o
 obj-$(CONFIG_LEDS_TRIGGER_TIMER)	+= ledtrig-timer.o
 obj-$(CONFIG_LEDS_TRIGGER_IDE_DISK)	+= ledtrig-ide-disk.o
 obj-$(CONFIG_LEDS_TRIGGER_HEARTBEAT)	+= ledtrig-heartbeat.o
+obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+= ledtrig-netdev.o
 obj-$(CONFIG_LEDS_TRIGGER_BACKLIGHT)	+= ledtrig-backlight.o
 obj-$(CONFIG_LEDS_TRIGGER_GPIO)		+= ledtrig-gpio.o
 obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON)	+= ledtrig-default-on.o
diff --git a/drivers/leds/ledtrig-netdev.c b/drivers/leds/ledtrig-netdev.c
new file mode 100644
index 0000000..eeb5ac8
--- /dev/null
+++ b/drivers/leds/ledtrig-netdev.c
@@ -0,0 +1,475 @@
+/*
+ * LED Kernel Netdev Trigger
+ *
+ * Toggles the LED to reflect the link and traffic state of a named net device
+ *
+ * Copyright 2007 Oliver Jowett <oliver@...ncloud.com>
+ *
+ * Derived from ledtrig-timer.c which is:
+ *  Copyright 2005-2006 Openedhand Ltd.
+ *  Author: Richard Purdie <rpurdie@...nedhand.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/sysdev.h>
+#include <linux/netdevice.h>
+#include <linux/timer.h>
+#include <linux/ctype.h>
+#include <linux/leds.h>
+#include <linux/version.h>
+#include <net/net_namespace.h>
+
+#include "leds.h"
+
+/*
+ * Configurable sysfs attributes:
+ *
+ * device_name - network device name to monitor
+ *
+ * interval - duration of LED blink, in milliseconds
+ *
+ * Each of the following attributes may be "enabled" or "disabled":
+ *
+ * link - if enabled, the LED's normal state reflects
+ *	whether the link is up (has carrier)
+ * transmit - if enabled, the LED blinks on transmitted data
+ * receive - if enabled, the LED blinks on received data
+ *
+ * Some suggestions:
+ *
+ *  Simple link status LED:
+ *  $ echo netdev >someled/trigger
+ *  $ echo eth0 >someled/device_name
+ *  $ echo enabled >someled/link
+ *
+ *  Ethernet-style link/activity LED:
+ *  $ echo netdev >someled/trigger
+ *  $ echo eth0 >someled/device_name
+ *  $ echo enabled >someled/link
+ *  $ echo enabled >someled/transmit
+ *  $ echo enabled >someled/receive
+ *
+ *  Modem-style tx/rx LEDs:
+ *  $ echo netdev >led1/trigger
+ *  $ echo ppp0 >led1/device_name
+ *  $ echo enabled >led1/transmit
+ *  $ echo netdev >led2/trigger
+ *  $ echo ppp0 >led2/device_name
+ *  $ echo enabled >led2/receive
+ */
+
+#define MODE_LINK 1
+#define MODE_TX	  2
+#define MODE_RX	  4
+
+struct led_netdev_data {
+	rwlock_t lock;
+
+	struct timer_list timer;
+	struct notifier_block notifier;
+
+	struct led_classdev *led_cdev;
+	struct net_device *net_dev;
+
+	char device_name[IFNAMSIZ];
+	unsigned interval;
+	unsigned mode;
+	unsigned link_up;
+	unsigned last_activity;
+};
+
+static void set_baseline_state(struct led_netdev_data *trigger_data)
+{
+	if ((trigger_data->mode & MODE_LINK) != 0 && trigger_data->link_up)
+		led_set_brightness(trigger_data->led_cdev, LED_FULL);
+	else
+		led_set_brightness(trigger_data->led_cdev, LED_OFF);
+
+	if ((trigger_data->mode & (MODE_TX | MODE_RX)) != 0 &&
+	    trigger_data->link_up)
+		mod_timer(&trigger_data->timer,
+			  jiffies + trigger_data->interval);
+	else
+		del_timer(&trigger_data->timer);
+}
+
+static ssize_t led_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;
+
+	read_lock(&trigger_data->lock);
+	sprintf(buf, "%s\n", trigger_data->device_name);
+	read_unlock(&trigger_data->lock);
+
+	return strlen(buf) + 1;
+}
+
+static ssize_t led_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 < 0 || size >= IFNAMSIZ)
+		return -EINVAL;
+
+	write_lock(&trigger_data->lock);
+
+	strcpy(trigger_data->device_name, buf);
+	if (size > 0 && trigger_data->device_name[size-1] == '\n')
+		trigger_data->device_name[size-1] = 0;
+
+	if (trigger_data->device_name[0] != 0) {
+		/* check for existing device to update from */
+		struct net_device *dev =
+			dev_get_by_name(&init_net, trigger_data->device_name);
+		if (dev != NULL) {
+			unsigned int flags = dev_get_flags(dev);
+			trigger_data->net_dev = dev;
+			trigger_data->link_up = (flags & IFF_LOWER_UP) != 0;
+		}
+		/* updates LEDs, may start timers */
+		set_baseline_state(trigger_data);
+	}
+
+	write_unlock(&trigger_data->lock);
+	return size;
+}
+
+static DEVICE_ATTR(device_name, 0644,
+		   led_device_name_show, led_device_name_store);
+
+static const char enabled[] = "enabled";
+static const char disabled[] = "disabled";
+
+static ssize_t led_show_mode(struct device *dev,
+			     struct device_attribute *attr, char *buf,
+			     unsigned mode_bit)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+
+	return sprintf(buf, "%s\n", (trigger_data->mode & mode_bit) ?
+		       enabled : disabled);
+}
+
+static void led_mode_set(struct led_netdev_data *data, unsigned bit)
+{
+	write_lock(&data->lock);
+	data->mode |= bit;
+	set_baseline_state(data);
+	write_unlock(&data->lock);
+}
+
+static void led_mode_clear(struct led_netdev_data *data, unsigned bit)
+{
+	write_lock(&data->lock);
+	data->mode &= ~bit;
+	set_baseline_state(data);
+	write_unlock(&data->lock);
+}
+
+static ssize_t led_store_mode(struct device *dev,
+			      struct device_attribute *attr, const char *buf,
+			      size_t size, unsigned mode_bit)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct led_netdev_data *trigger_data = led_cdev->trigger_data;
+	char *cp;
+	int len = size;
+
+	cp = memchr(buf, '\n', size);
+	if (cp)
+		len = cp - buf;
+	if (len == sizeof(enabled) - 1 && strncmp(buf, enabled, len) == 0)
+		led_mode_set(trigger_data, mode_bit);
+	else if (len == sizeof(disabled) - 1 &&
+		 strncmp(buf, disabled, len) == 0)
+		led_mode_clear(trigger_data, mode_bit);
+	else
+		return -EINVAL;
+	return size;
+}
+
+#define LED_NETDEV_ATTR(name, mode_bit)					\
+static ssize_t led_show_##name(struct device *dev,			\
+			       struct device_attribute *attr,		\
+			       char *buf)				\
+{									\
+	return led_show_mode(dev, attr, buf, mode_bit);			\
+}									\
+									\
+static ssize_t led_store_##name(struct device *dev,			\
+				struct device_attribute *attr,	\
+				const char *buf, size_t size)		\
+{									\
+	return led_store_mode(dev, attr, buf, size, mode_bit);		\
+}									\
+									\
+static DEVICE_ATTR(name, 0644, led_show_##name, led_store_##name)
+
+LED_NETDEV_ATTR(link, MODE_LINK);
+LED_NETDEV_ATTR(transmit, MODE_TX);
+LED_NETDEV_ATTR(receive, MODE_RX);
+
+static ssize_t led_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;
+
+	read_lock(&trigger_data->lock);
+	sprintf(buf, "%u\n", jiffies_to_msecs(trigger_data->interval));
+	read_unlock(&trigger_data->lock);
+
+	return strlen(buf) + 1;
+}
+
+static ssize_t led_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 = strict_strtoul(buf, 10, &value);
+	if (ret < 0)
+		return ret;
+
+	/* impose some basic bounds on the timer interval */
+	if (value >= 5 && value <= 10000) {
+		write_lock(&trigger_data->lock);
+		trigger_data->interval = msecs_to_jiffies(value);
+		set_baseline_state(trigger_data);	/* resets timer */
+		write_unlock(&trigger_data->lock);
+		return size;
+	} else {
+		return -EINVAL;
+	}
+}
+
+static DEVICE_ATTR(interval, 0644, led_interval_show, led_interval_store);
+
+static int netdev_trig_notify(struct notifier_block *nb,
+			      unsigned long evt,
+			      void *dv)
+{
+	struct net_device *dev = 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)
+		return NOTIFY_DONE;
+
+	write_lock(&trigger_data->lock);
+
+	if (strcmp(dev->name, trigger_data->device_name))
+		goto done;
+
+	if (evt == NETDEV_REGISTER) {
+		if (trigger_data->net_dev != NULL)
+			dev_put(trigger_data->net_dev);
+		dev_hold(dev);
+		trigger_data->net_dev = dev;
+		trigger_data->link_up = 0;
+		goto done;
+	}
+
+	if (evt == NETDEV_UNREGISTER && trigger_data->net_dev != NULL) {
+		dev_put(trigger_data->net_dev);
+		trigger_data->net_dev = NULL;
+		goto done;
+	}
+
+	/* UP / DOWN / CHANGE */
+
+	trigger_data->link_up = (evt != NETDEV_DOWN && netif_carrier_ok(dev));
+	set_baseline_state(trigger_data);
+
+done:
+	write_unlock(&trigger_data->lock);
+	return NOTIFY_DONE;
+}
+
+/* here's the real work! */
+static void netdev_trig_timer(unsigned long arg)
+{
+	struct led_netdev_data *trigger_data = (struct led_netdev_data *)arg;
+	struct rtnl_link_stats64 temp;
+	const struct rtnl_link_stats64 *dev_stats;
+	unsigned new_activity;
+
+	write_lock(&trigger_data->lock);
+
+	if (!trigger_data->link_up || !trigger_data->net_dev ||
+	    (trigger_data->mode & (MODE_TX | MODE_RX)) == 0) {
+		/* we don't need to do timer work, just reflect link state. */
+		int on = (trigger_data->mode & MODE_LINK) != 0 &&
+			trigger_data->link_up;
+		led_set_brightness(trigger_data->led_cdev,
+				   on ? LED_FULL : LED_OFF);
+		goto no_restart;
+	}
+
+	dev_stats = dev_get_stats(trigger_data->net_dev, &temp);
+
+	new_activity =
+		((trigger_data->mode & MODE_TX) ? dev_stats->tx_packets : 0) +
+		((trigger_data->mode & MODE_RX) ? dev_stats->rx_packets : 0);
+
+	if (trigger_data->mode & MODE_LINK) {
+		/* base state is ON (link present) */
+		/* if there's no link, we don't get this far
+		   and the LED is off */
+
+		/* OFF -> ON always */
+		/* ON -> OFF on activity */
+		if (trigger_data->led_cdev->brightness == LED_OFF)
+			led_set_brightness(trigger_data->led_cdev, LED_FULL);
+		else if (trigger_data->last_activity != new_activity)
+			led_set_brightness(trigger_data->led_cdev, LED_OFF);
+	} else {
+		/* base state is OFF */
+		/* ON -> OFF always */
+		/* OFF -> ON on activity */
+		if (trigger_data->led_cdev->brightness == LED_FULL)
+			led_set_brightness(trigger_data->led_cdev, LED_OFF);
+		else if (trigger_data->last_activity != new_activity)
+			led_set_brightness(trigger_data->led_cdev, LED_FULL);
+	}
+
+	trigger_data->last_activity = new_activity;
+	mod_timer(&trigger_data->timer, jiffies + trigger_data->interval);
+
+no_restart:
+	write_unlock(&trigger_data->lock);
+}
+
+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;
+
+	rwlock_init(&trigger_data->lock);
+
+	trigger_data->notifier.notifier_call = netdev_trig_notify;
+	trigger_data->notifier.priority = 10;
+
+	setup_timer(&trigger_data->timer, netdev_trig_timer,
+		    (unsigned long) trigger_data);
+
+	trigger_data->led_cdev = led_cdev;
+	trigger_data->net_dev = NULL;
+	trigger_data->device_name[0] = 0;
+
+	trigger_data->mode = 0;
+	trigger_data->interval = msecs_to_jiffies(50);
+	trigger_data->link_up = 0;
+	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_transmit);
+	if (rc)
+		goto err_out_link;
+	rc = device_create_file(led_cdev->dev, &dev_attr_receive);
+	if (rc)
+		goto err_out_transmit;
+	rc = device_create_file(led_cdev->dev, &dev_attr_interval);
+	if (rc)
+		goto err_out_receive;
+
+	register_netdevice_notifier(&trigger_data->notifier);
+	return;
+
+err_out_receive:
+	device_remove_file(led_cdev->dev, &dev_attr_receive);
+err_out_transmit:
+	device_remove_file(led_cdev->dev, &dev_attr_transmit);
+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_transmit);
+		device_remove_file(led_cdev->dev, &dev_attr_receive);
+		device_remove_file(led_cdev->dev, &dev_attr_interval);
+
+		write_lock(&trigger_data->lock);
+
+		if (trigger_data->net_dev) {
+			dev_put(trigger_data->net_dev);
+			trigger_data->net_dev = NULL;
+		}
+
+		write_unlock(&trigger_data->lock);
+
+		del_timer_sync(&trigger_data->timer);
+
+		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("Oliver Jowett <oliver@...ncloud.com>");
+MODULE_DESCRIPTION("Netdev LED trigger");
+MODULE_LICENSE("GPL");
-- 
1.7.2.3

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