path: root/packages/linux/ixp4xx-kernel/2.6.16/951-ixp4xx-leds-cpu-activity.patch

This patches the new LEDs code to add cpu activity and
inactivity triggers to the timer triggers.  The new triggers
set the LED with the trigger to different states (on,
flashing or off) according to whether or not all CPUs
are idle.

Signed-off-by: John Bowler <jbowler@acm.org>

---
 arch/arm/kernel/process.c  |   11 
 drivers/leds/Kconfig       |    9 
 drivers/leds/Makefile      |    1 
 drivers/leds/ledtrig-cpu.c |  501 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/leds.h       |    9 
 5 files changed, 531 insertions(+)

--- linux-ixp4xx.orig/arch/arm/kernel/process.c	2006-02-21 00:53:28.000000000 +0100
+++ linux-ixp4xx/arch/arm/kernel/process.c	2006-02-21 01:03:33.000000000 +0100
@@ -27,6 +27,7 @@
 #include <linux/kallsyms.h>
 #include <linux/init.h>
 #include <linux/cpu.h>
+#include <linux/leds.h>
 #include <linux/elfcore.h>
 
 #include <asm/leds.h>
@@ -80,6 +81,12 @@ void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
 /*
+ * CPU activity indicator.
+ */
+void (*leds_idle)(int is_idle);
+EXPORT_SYMBOL(leds_idle);
+
+/*
  * This is our default idle handler.  We need to disable
  * interrupts here to ensure we don't miss a wakeup call.
  */
@@ -120,8 +127,12 @@ void cpu_idle(void)
 		if (!idle)
 			idle = default_idle;
 		leds_event(led_idle_start);
+		if (leds_idle)
+			leds_idle(1);
 		while (!need_resched())
 			idle();
+		if (leds_idle)
+			leds_idle(0);
 		leds_event(led_idle_end);
 		preempt_enable_no_resched();
 		schedule();
--- linux-ixp4xx.orig/drivers/leds/Kconfig	2006-02-21 00:58:36.000000000 +0100
+++ linux-ixp4xx/drivers/leds/Kconfig	2006-02-21 01:03:33.000000000 +0100
@@ -66,5 +66,14 @@ config LEDS_TRIGGER_TIMER
 	  This allows LEDs to be controlled by a programmable timer
 	  via sysfs. If unsure, say Y.
 
+config LEDS_TRIGGER_CPU_ACTIVITY
+	tristate "LED CPU activity trigger"
+	depends LEDS_TRIGGER_TIMER
+	help
+	  This allows LEDs to be set to show cpu activity via sysfs.
+	  The LED will blink when the cpu is active and stay steady
+	  (on or off according to the trigger selected) when idle.
+	  If unsure, say Y.
+
 endmenu
 
--- linux-ixp4xx.orig/drivers/leds/Makefile	2006-02-21 00:58:36.000000000 +0100
+++ linux-ixp4xx/drivers/leds/Makefile	2006-02-21 01:03:33.000000000 +0100
@@ -13,3 +13,4 @@ obj-$(CONFIG_LEDS_TOSA)			+= leds-tosa.o
 
 # LED Triggers
 obj-$(CONFIG_LEDS_TRIGGER_TIMER)	+= ledtrig-timer.o
+obj-$(CONFIG_LEDS_TRIGGER_CPU_ACTIVITY)	+= ledtrig-cpu.o
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-ixp4xx/drivers/leds/ledtrig-cpu.c	2006-02-21 01:08:57.000000000 +0100
@@ -0,0 +1,501 @@
+/*
+ * LEDs CPU activity trigger
+ *
+ * Author: John Bowler <jbowler@acm.org>
+ *
+ * Copyright (c) 2006 John Bowler
+ *
+ * Permission is hereby granted, free of charge, to any
+ * person obtaining a copy of this software and associated
+ * documentation files (the "Software"), to deal in the
+ * Software without restriction, including without
+ * limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the
+ * following conditions:
+ *
+ * The above copyright notice and this permission notice
+ * shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ * ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+ * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+ * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+ * SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/ctype.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/device.h>
+
+#include <linux/leds.h>
+#include "leds.h"
+
+//#include <linux/list.h>
+//#include <linux/sysdev.h>
+
+
+/*
+ * To simplify this the LED state is given for each case of
+ * CPU state - idle or active.  The LED can be:
+ *
+ * off
+ * flash - slow for idle, fast (flicker) for active
+ * on
+ *
+ * This gives two useless states - off/off and on/on
+ */
+typedef enum cpu_trigger_led_state {
+	cpu_led_off,
+	cpu_led_flash,
+	cpu_led_on,
+	cpu_led_invalid
+} cpu_trigger_led_state;
+
+static const char *const cpu_trigger_names[] = {
+	"off",
+	"flash",
+	"on",
+	"invalid"
+};
+
+/* Forward declaration - this is called back when an LED property
+ * is changed.
+ */
+static void leds_cpu_trigger_state_change(void);
+
+/*
+ * These constants define the actual mark/space of the flashing
+ * in jiffies.  msecs_to_jiffies rounds up and is compile time
+ * evaluable for constant arguments.  Writing the ?: stuff below
+ * this way ensures the compiler doesn't think it needs to
+ * compile in the math of msecs_to_jiffies.
+ *
+ * These values have been determined by experiment to work well
+ * for the ready/status LED on a LinkSys NSLU2 (light piped) and
+ * for the user LED on a Loft (Gateway Avila variant) board where
+ * the LED was directly visible.  Light Output Varies Everywhere.
+ */
+#define LEDS_CPU_ACTIVE_MARK	msecs_to_jiffies(40)
+#define LEDS_CPU_IDLE_MARK	msecs_to_jiffies(800)
+#define LEDS_CPU_ACTIVE_SPACE	msecs_to_jiffies(60)
+#define LEDS_CPU_IDLE_SPACE	msecs_to_jiffies(800)
+
+
+/*
+ * Individual LEDs ------------------------------------------------------------
+ */
+struct cpu_trigger_data {
+	cpu_trigger_led_state active; /* Behaviour when the CPU is active. */
+	cpu_trigger_led_state idle;   /* Behaviour when the CPU is idle. */
+};
+
+/*
+ * LED state change - called when the state of a single LED might
+ * have changed.  Returns true if the LED is blinking.  The argument
+ * is the blink state - the brightness of the blinking LED.
+ */
+static int leds_cpu_trigger_led_state_change(struct led_classdev *led,
+		int is_active, enum led_brightness brightness)
+{
+	int is_blinking = 0;
+
+	write_lock(&led->lock);
+	{
+		struct cpu_trigger_data *data = led->trigger_data;
+
+		/* Find the new brightness for the LED, if the LED is
+		 * set to flash then the brightness passed in is the
+		 * required value.
+		 */
+		if (likely(data != 0))
+			switch (is_active ? data->active : data->idle) {
+			case cpu_led_off:   brightness = LED_OFF;  break;
+			case cpu_led_flash: is_blinking = 1;       break;
+			case cpu_led_on:    brightness = LED_FULL; break;
+			}
+		else
+			brightness = is_active ? LED_FULL : LED_OFF;
+
+		led_set_brightness(led, brightness);
+	}
+	write_unlock(&led->lock);
+
+	return is_blinking;
+}
+
+/*
+ * sysfs properties, the property is output at an list of the
+ * values with the current setting enclosed in []
+ */
+static ssize_t leds_cpu_trigger_show_prop(struct class_device *dev, char *buf,
+		size_t where)
+{
+	struct led_classdev     *led = dev->class_data;
+	cpu_trigger_led_state  item = cpu_led_invalid, i;
+	char                  *next;
+
+	read_lock(&led->lock);
+	{
+		if (likely(led->trigger_data != 0))
+			item = *(const cpu_trigger_led_state*)(
+					led->trigger_data + where);
+	}
+	read_unlock(&led->lock);
+
+	for (i=0, next=buf; i<cpu_led_invalid; ++i) {
+		const char *name = cpu_trigger_names[i];
+		size_t len = strlen(name);
+
+		if (i == item)
+			*next++ = '[';
+		memcpy(next, name, len);
+		next += len;
+		if (i == item)
+			*next++ = ']';
+		*next++ = ' ';
+	}
+
+	next[-1] = '\n';
+	*next++ = 0;
+
+	return next - buf;
+}
+
+static ssize_t leds_cpu_trigger_show_active(struct class_device *dev, char *buf)
+{
+	return leds_cpu_trigger_show_prop(dev, buf,
+			offsetof(struct cpu_trigger_data, active));
+}
+
+static ssize_t leds_cpu_trigger_show_idle(struct class_device *dev, char *buf)
+{
+	return leds_cpu_trigger_show_prop(dev, buf,
+			offsetof(struct cpu_trigger_data, idle));
+}
+
+/*
+ * Any matching leading substring selects a property - so "onoffonoff"
+ * sets the property to off.
+ */
+static ssize_t leds_cpu_trigger_store_prop(struct class_device *dev,
+		const char *buf, size_t size, size_t where)
+{
+	size_t rc = 0;
+	cpu_trigger_led_state value = 0/*sic*/;
+	struct led_classdev *led;
+
+	/* ignore space characters before the value. */
+	while (rc < size && isspace(buf[rc]))
+		++rc;
+	if (rc >= size)
+		return rc;
+
+	/* look for a simple match against the trigger name, case
+	 * sensitive.
+	 */
+	do {
+		const char *name = cpu_trigger_names[value];
+		size_t len = strlen(name);
+		if (len <= size && memcmp(buf+rc, name, len) == 0) {
+			rc = len;
+			break;
+		}
+		if (++value >= cpu_led_invalid)
+			return -EINVAL;
+	} while (1);
+
+	led = dev->class_data;
+	write_lock(&led->lock);
+	{
+		if (likely(led->trigger_data != 0))
+			*(cpu_trigger_led_state*)(
+					led->trigger_data + where) = value;
+
+	}
+	write_unlock(&led->lock);
+
+	return rc;
+}
+
+static ssize_t leds_cpu_trigger_store_active(struct class_device *dev,
+		const char *buf, size_t size)
+{
+	ssize_t rc = leds_cpu_trigger_store_prop(dev, buf, size,
+			offsetof(struct cpu_trigger_data, active));
+	/*
+	 * At least one CPU must be active (otherwise who is doing this?)
+	 * Call down into the global state below to cause an update
+	 * to happen now.
+	 */
+	leds_cpu_trigger_state_change();
+	return rc;
+}
+
+static ssize_t leds_cpu_trigger_store_idle(struct class_device *dev,
+		const char *buf, size_t size)
+{
+	return leds_cpu_trigger_store_prop(dev, buf, size,
+			offsetof(struct cpu_trigger_data, idle));
+}
+
+static CLASS_DEVICE_ATTR(active, 0644, leds_cpu_trigger_show_active,
+					leds_cpu_trigger_store_active);
+
+static CLASS_DEVICE_ATTR(idle, 0644, leds_cpu_trigger_show_idle,
+					leds_cpu_trigger_store_idle);
+
+/*
+ * Activate and deactivate are called on individual LEDs when the
+ * LED trigger property is changed.  The LED write lock is held.
+ */
+static void leds_cpu_trigger_activate(struct led_classdev *led)
+{
+	/*
+	 * The initial setting of the trigger is simple CPU activity
+	 * with the LED off for idle and on for active.  Consequently
+	 * there is no need to mess with the global state initially,
+	 * we know the CPU is active at this moment!
+	 */
+	struct cpu_trigger_data *data = kmalloc(sizeof *data, GFP_KERNEL);
+	if (unlikely(data == 0))
+		return;
+
+	data->active = cpu_led_on;
+	data->idle = cpu_led_off;
+	led->trigger_data = data;
+
+	class_device_create_file(led->class_dev, &class_device_attr_active);
+	class_device_create_file(led->class_dev, &class_device_attr_idle);
+
+	led_set_brightness(led, LED_FULL);
+}
+
+static void leds_cpu_trigger_deactivate(struct led_classdev *led)
+{
+	struct cpu_trigger_data *data = led->trigger_data;
+	if (likely(data != 0)) {
+		led_set_brightness(led, LED_OFF);
+
+		class_device_remove_file(led->class_dev, &class_device_attr_idle);
+		class_device_remove_file(led->class_dev, &class_device_attr_active);
+
+		led->trigger_data = 0;
+		kfree(data);
+	}
+}
+
+
+/*
+ * Global state  --------------------------------------------------------------
+ *
+ * This is global because the CPU state is global and we only need one timer to
+ * do this stuff.
+ */
+typedef struct leds_cpu_trigger_data {
+	struct led_trigger trigger; /* the lock in here protects everything */
+	struct timer_list  timer;
+	unsigned long      last_active_time; /* record of last jiffies */
+	unsigned long      last_idle_time;   /* record of last jiffies */
+	int                count_active;     /* number of active CPUs */
+} leds_cpu_trigger_data;
+
+/*
+ * Mark state - uses the current time (jiffies) to work out
+ * whether this is a mark or space.
+ */
+static int leds_cpu_trigger_mark(struct leds_cpu_trigger_data *data,
+		unsigned long now) {
+	if (data->count_active > 0) {
+		unsigned long elapsed = now - data->last_active_time;
+		elapsed %= LEDS_CPU_ACTIVE_SPACE + LEDS_CPU_ACTIVE_MARK;
+		data->last_active_time = now - elapsed;
+		return elapsed > LEDS_CPU_ACTIVE_SPACE;
+	} else {
+		unsigned long elapsed = now - data->last_idle_time;
+		elapsed %= LEDS_CPU_IDLE_SPACE + LEDS_CPU_IDLE_MARK;
+		data->last_idle_time = now - elapsed;
+		return elapsed > LEDS_CPU_IDLE_SPACE;
+	}
+}
+
+
+/*
+ * State change - given information about the nature of the
+ * (possible) state change call up to each LED to adjust its
+ * state.  Returns true if any LED is blinking.  The lock
+ * must be held (a read lock is adequate).
+ */
+static int leds_cpu_trigger_scan_leds(struct leds_cpu_trigger_data *data,
+		unsigned long now)
+{
+	int blinking = 0;
+	const int active = data->count_active > 0;
+	const enum led_brightness brightness =
+		leds_cpu_trigger_mark(data, now) ? LED_FULL : LED_OFF;
+	struct list_head *entry;
+
+	list_for_each(entry, &data->trigger.led_cdevs) {
+		struct led_classdev *led =
+			list_entry(entry, struct led_classdev, trig_list);
+
+		blinking |= leds_cpu_trigger_led_state_change(led,
+				active, brightness);
+	}
+
+	return blinking;
+}
+
+/*
+ * Set the timer correctly according to the current state, the lock
+ * must be held for write.
+ */
+static void leds_cpu_trigger_set_timer(struct leds_cpu_trigger_data *state,
+		unsigned long now)
+{
+	unsigned long next;
+	if (state->count_active > 0) {
+		next = state->last_active_time;
+		if (now - next > LEDS_CPU_ACTIVE_SPACE)
+			next += LEDS_CPU_ACTIVE_MARK;
+		next += LEDS_CPU_ACTIVE_SPACE;
+	} else {
+		next = state->last_idle_time;
+		if (now - next > LEDS_CPU_IDLE_SPACE)
+			next += LEDS_CPU_IDLE_MARK;
+		next += LEDS_CPU_IDLE_SPACE;
+	}
+	mod_timer(&state->timer, next);
+}
+
+/*
+ * The timer callback if the LED is currently flashing, the callback
+ * calls the state change function and, if that returns true, meaning
+ * that at least one LED is still blinking, the timer is restarted
+ * with the correct timeout.
+ */
+static void leds_cpu_trigger_timer_callback(unsigned long data)
+{
+	struct leds_cpu_trigger_data *state =
+				(struct leds_cpu_trigger_data *)data;
+
+	write_lock(&state->trigger.leddev_list_lock);
+	{
+		unsigned long now = jiffies;
+
+		/* If at least one LED is set to flash; set the timer
+		 * again (this won't reset the timer set within the
+		 * idle loop).
+		 */
+		if (leds_cpu_trigger_scan_leds(state, now))
+			leds_cpu_trigger_set_timer(state, now);
+	}
+	write_unlock(&state->trigger.leddev_list_lock);
+}
+
+
+/*
+ * There is one global control structure, one timer and one set
+ * of state for active CPUs shared across all the LEDs.  Individual
+ * LEDs say how this state to be handled.  It is currently *not*
+ * possible to show per-cpu activity on individual LEDs, the code
+ * maintains a count of active CPUs and the state is only 'idle'
+ * if all CPUs are idle.
+ */
+static struct leds_cpu_trigger_data leds_cpu_trigger = {
+	.trigger = {
+		.name       = "cpu",
+		.activate   = leds_cpu_trigger_activate,
+		.deactivate = leds_cpu_trigger_deactivate,
+	} ,
+	.timer   = TIMER_INITIALIZER(leds_cpu_trigger_timer_callback, 0,
+			(unsigned long)&leds_cpu_trigger),
+	.last_active_time = 0,
+	.last_idle_time   = 0,
+	.count_active     = 0,
+};
+
+/*
+ * State change - callback from an individual LED on a property change which
+ * might require a redisplay.
+ */
+static void leds_cpu_trigger_state_change() {
+	write_lock(&leds_cpu_trigger.trigger.leddev_list_lock);
+	{
+		unsigned long now = jiffies;
+
+		if (leds_cpu_trigger_scan_leds(&leds_cpu_trigger, now) &&
+			!timer_pending(&leds_cpu_trigger.timer))
+			leds_cpu_trigger_set_timer(&leds_cpu_trigger, now);
+	}
+	write_unlock(&leds_cpu_trigger.trigger.leddev_list_lock);
+}
+
+/*
+ * Called from every CPU at the start and end of the idle loop.
+ * The active count is initially 0, even though CPUs are running,
+ * so the code below must check for the resultant underflow.
+ *
+ * If the idle behaviour is 'flash' then when the timer times out
+ * it will take the CPU out of idle, set the active state (which
+ * may also be flash), drop back into idle and reset the timer to
+ * the idle timeout...
+ */
+static void leds_cpu_trigger_idle(int is_idle)
+{
+	write_lock(&leds_cpu_trigger.trigger.leddev_list_lock);
+	if ((is_idle && leds_cpu_trigger.count_active > 0 &&
+				--leds_cpu_trigger.count_active == 0) ||
+	    (!is_idle && leds_cpu_trigger.count_active < num_online_cpus() &&
+	     			++leds_cpu_trigger.count_active == 1)) {
+		unsigned long now = jiffies;
+
+		/* State change - the system just became idle or active,
+		 * call the del_timer first in an attempt to minimise
+		 * getting a timer interrupt which will take us unnecessarily
+		 * out of idle (this doesn't matter).
+		 */
+		del_timer(&leds_cpu_trigger.timer);
+		if (leds_cpu_trigger_scan_leds(&leds_cpu_trigger, now))
+			leds_cpu_trigger_set_timer(&leds_cpu_trigger, now);
+	}
+	write_unlock(&leds_cpu_trigger.trigger.leddev_list_lock);
+}
+
+/*
+ * Module init and exit - register the trigger, then store
+ * the idle callback in the arch-specific global.  For this
+ * module to link (into the kernel) or load (into a running
+ * kernel) the architecture must define the leds_idle global.
+ */
+static int __init leds_cpu_trigger_init(void)
+{
+	int rc = led_trigger_register(&leds_cpu_trigger.trigger);
+	leds_idle = leds_cpu_trigger_idle;
+	return rc;
+}
+module_init(leds_cpu_trigger_init);
+
+static void __exit leds_cpu_trigger_exit(void)
+{
+	leds_idle = 0;
+	del_timer_sync(&leds_cpu_trigger.timer);
+	led_trigger_unregister(&leds_cpu_trigger.trigger);
+}
+module_exit(leds_cpu_trigger_exit);
+
+MODULE_AUTHOR("John Bowler <jbowler@acm.org>");
+MODULE_DESCRIPTION("CPU activity LED trigger");
+MODULE_LICENSE("MIT");
--- linux-ixp4xx.orig/include/linux/leds.h	2006-02-21 00:54:33.000000000 +0100
+++ linux-ixp4xx/include/linux/leds.h	2006-02-21 01:03:33.000000000 +0100
@@ -102,4 +102,13 @@ void led_trigger_event(struct led_trigge
 #define led_trigger_event(x, y) do {} while(0)
 
 #endif
+
+/*
+ * CPU activity indication.
+ */
+/* Idle callback - call with is_idle==1 at the start of the idle loop
+ * and with is_idle==0 at the end.  This symbol must be defined by
+ * the arch core to be able to use LEDS_TRIGGER_CPU_ACTIVITY
+ */
+extern void (*leds_idle)(int is_idle);
 #endif		/* __LINUX_LEDS_H_INCLUDED */