Logo Search packages:      
Sourcecode: linux version File versions  Download package

windfarm_core.c

/*
 * Windfarm PowerMac thermal control. Core
 *
 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
 *                    <benh@kernel.crashing.org>
 *
 * Released under the term of the GNU GPL v2.
 *
 * This core code tracks the list of sensors & controls, register
 * clients, and holds the kernel thread used for control.
 *
 * TODO:
 *
 * Add some information about sensor/control type and data format to
 * sensors/controls, and have the sysfs attribute stuff be moved
 * generically here instead of hard coded in the platform specific
 * driver as it us currently
 *
 * This however requires solving some annoying lifetime issues with
 * sysfs which doesn't seem to have lifetime rules for struct attribute,
 * I may have to create full features kobjects for every sensor/control
 * instead which is a bit of an overkill imho
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/jiffies.h>
#include <linux/reboot.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/freezer.h>

#include <asm/prom.h>

#include "windfarm.h"

#define VERSION "0.2"

#undef DEBUG

#ifdef DEBUG
#define DBG(args...)    printk(args)
#else
#define DBG(args...)    do { } while(0)
#endif

static LIST_HEAD(wf_controls);
static LIST_HEAD(wf_sensors);
static DEFINE_MUTEX(wf_lock);
static BLOCKING_NOTIFIER_HEAD(wf_client_list);
static int wf_client_count;
static unsigned int wf_overtemp;
static unsigned int wf_overtemp_counter;
struct task_struct *wf_thread;

static struct platform_device wf_platform_device = {
      .name = "windfarm",
};

/*
 * Utilities & tick thread
 */

static inline void wf_notify(int event, void *param)
{
      blocking_notifier_call_chain(&wf_client_list, event, param);
}

int wf_critical_overtemp(void)
{
      static char * critical_overtemp_path = "/sbin/critical_overtemp";
      char *argv[] = { critical_overtemp_path, NULL };
      static char *envp[] = { "HOME=/",
                        "TERM=linux",
                        "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
                        NULL };

      return call_usermodehelper(critical_overtemp_path,
                           argv, envp, UMH_WAIT_EXEC);
}
EXPORT_SYMBOL_GPL(wf_critical_overtemp);

static int wf_thread_func(void *data)
{
      unsigned long next, delay;

      next = jiffies;

      DBG("wf: thread started\n");

      set_freezable();
      while (!kthread_should_stop()) {
            try_to_freeze();

            if (time_after_eq(jiffies, next)) {
                  wf_notify(WF_EVENT_TICK, NULL);
                  if (wf_overtemp) {
                        wf_overtemp_counter++;
                        /* 10 seconds overtemp, notify userland */
                        if (wf_overtemp_counter > 10)
                              wf_critical_overtemp();
                        /* 30 seconds, shutdown */
                        if (wf_overtemp_counter > 30) {
                              printk(KERN_ERR "windfarm: Overtemp "
                                     "for more than 30"
                                     " seconds, shutting down\n");
                              machine_power_off();
                        }
                  }
                  next += HZ;
            }

            delay = next - jiffies;
            if (delay <= HZ)
                  schedule_timeout_interruptible(delay);
      }

      DBG("wf: thread stopped\n");

      return 0;
}

static void wf_start_thread(void)
{
      wf_thread = kthread_run(wf_thread_func, NULL, "kwindfarm");
      if (IS_ERR(wf_thread)) {
            printk(KERN_ERR "windfarm: failed to create thread,err %ld\n",
                   PTR_ERR(wf_thread));
            wf_thread = NULL;
      }
}


static void wf_stop_thread(void)
{
      if (wf_thread)
            kthread_stop(wf_thread);
      wf_thread = NULL;
}

/*
 * Controls
 */

static void wf_control_release(struct kref *kref)
{
      struct wf_control *ct = container_of(kref, struct wf_control, ref);

      DBG("wf: Deleting control %s\n", ct->name);

      if (ct->ops && ct->ops->release)
            ct->ops->release(ct);
      else
            kfree(ct);
}

static ssize_t wf_show_control(struct device *dev,
                         struct device_attribute *attr, char *buf)
{
      struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
      s32 val = 0;
      int err;

      err = ctrl->ops->get_value(ctrl, &val);
      if (err < 0)
            return err;
      return sprintf(buf, "%d\n", val);
}

/* This is really only for debugging... */
static ssize_t wf_store_control(struct device *dev,
                        struct device_attribute *attr,
                        const char *buf, size_t count)
{
      struct wf_control *ctrl = container_of(attr, struct wf_control, attr);
      int val;
      int err;
      char *endp;

      val = simple_strtoul(buf, &endp, 0);
      while (endp < buf + count && (*endp == ' ' || *endp == '\n'))
            ++endp;
      if (endp - buf < count)
            return -EINVAL;
      err = ctrl->ops->set_value(ctrl, val);
      if (err < 0)
            return err;
      return count;
}

int wf_register_control(struct wf_control *new_ct)
{
      struct wf_control *ct;

      mutex_lock(&wf_lock);
      list_for_each_entry(ct, &wf_controls, link) {
            if (!strcmp(ct->name, new_ct->name)) {
                  printk(KERN_WARNING "windfarm: trying to register"
                         " duplicate control %s\n", ct->name);
                  mutex_unlock(&wf_lock);
                  return -EEXIST;
            }
      }
      kref_init(&new_ct->ref);
      list_add(&new_ct->link, &wf_controls);

      new_ct->attr.attr.name = new_ct->name;
      new_ct->attr.attr.mode = 0644;
      new_ct->attr.show = wf_show_control;
      new_ct->attr.store = wf_store_control;
      if (device_create_file(&wf_platform_device.dev, &new_ct->attr))
            printk(KERN_WARNING "windfarm: device_create_file failed"
                  " for %s\n", new_ct->name);
            /* the subsystem still does useful work without the file */

      DBG("wf: Registered control %s\n", new_ct->name);

      wf_notify(WF_EVENT_NEW_CONTROL, new_ct);
      mutex_unlock(&wf_lock);

      return 0;
}
EXPORT_SYMBOL_GPL(wf_register_control);

void wf_unregister_control(struct wf_control *ct)
{
      mutex_lock(&wf_lock);
      list_del(&ct->link);
      mutex_unlock(&wf_lock);

      DBG("wf: Unregistered control %s\n", ct->name);

      kref_put(&ct->ref, wf_control_release);
}
EXPORT_SYMBOL_GPL(wf_unregister_control);

struct wf_control * wf_find_control(const char *name)
{
      struct wf_control *ct;

      mutex_lock(&wf_lock);
      list_for_each_entry(ct, &wf_controls, link) {
            if (!strcmp(ct->name, name)) {
                  if (wf_get_control(ct))
                        ct = NULL;
                  mutex_unlock(&wf_lock);
                  return ct;
            }
      }
      mutex_unlock(&wf_lock);
      return NULL;
}
EXPORT_SYMBOL_GPL(wf_find_control);

int wf_get_control(struct wf_control *ct)
{
      if (!try_module_get(ct->ops->owner))
            return -ENODEV;
      kref_get(&ct->ref);
      return 0;
}
EXPORT_SYMBOL_GPL(wf_get_control);

void wf_put_control(struct wf_control *ct)
{
      struct module *mod = ct->ops->owner;
      kref_put(&ct->ref, wf_control_release);
      module_put(mod);
}
EXPORT_SYMBOL_GPL(wf_put_control);


/*
 * Sensors
 */


static void wf_sensor_release(struct kref *kref)
{
      struct wf_sensor *sr = container_of(kref, struct wf_sensor, ref);

      DBG("wf: Deleting sensor %s\n", sr->name);

      if (sr->ops && sr->ops->release)
            sr->ops->release(sr);
      else
            kfree(sr);
}

static ssize_t wf_show_sensor(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
      struct wf_sensor *sens = container_of(attr, struct wf_sensor, attr);
      s32 val = 0;
      int err;

      err = sens->ops->get_value(sens, &val);
      if (err < 0)
            return err;
      return sprintf(buf, "%d.%03d\n", FIX32TOPRINT(val));
}

int wf_register_sensor(struct wf_sensor *new_sr)
{
      struct wf_sensor *sr;

      mutex_lock(&wf_lock);
      list_for_each_entry(sr, &wf_sensors, link) {
            if (!strcmp(sr->name, new_sr->name)) {
                  printk(KERN_WARNING "windfarm: trying to register"
                         " duplicate sensor %s\n", sr->name);
                  mutex_unlock(&wf_lock);
                  return -EEXIST;
            }
      }
      kref_init(&new_sr->ref);
      list_add(&new_sr->link, &wf_sensors);

      new_sr->attr.attr.name = new_sr->name;
      new_sr->attr.attr.mode = 0444;
      new_sr->attr.show = wf_show_sensor;
      new_sr->attr.store = NULL;
      if (device_create_file(&wf_platform_device.dev, &new_sr->attr))
            printk(KERN_WARNING "windfarm: device_create_file failed"
                  " for %s\n", new_sr->name);
            /* the subsystem still does useful work without the file */

      DBG("wf: Registered sensor %s\n", new_sr->name);

      wf_notify(WF_EVENT_NEW_SENSOR, new_sr);
      mutex_unlock(&wf_lock);

      return 0;
}
EXPORT_SYMBOL_GPL(wf_register_sensor);

void wf_unregister_sensor(struct wf_sensor *sr)
{
      mutex_lock(&wf_lock);
      list_del(&sr->link);
      mutex_unlock(&wf_lock);

      DBG("wf: Unregistered sensor %s\n", sr->name);

      wf_put_sensor(sr);
}
EXPORT_SYMBOL_GPL(wf_unregister_sensor);

struct wf_sensor * wf_find_sensor(const char *name)
{
      struct wf_sensor *sr;

      mutex_lock(&wf_lock);
      list_for_each_entry(sr, &wf_sensors, link) {
            if (!strcmp(sr->name, name)) {
                  if (wf_get_sensor(sr))
                        sr = NULL;
                  mutex_unlock(&wf_lock);
                  return sr;
            }
      }
      mutex_unlock(&wf_lock);
      return NULL;
}
EXPORT_SYMBOL_GPL(wf_find_sensor);

int wf_get_sensor(struct wf_sensor *sr)
{
      if (!try_module_get(sr->ops->owner))
            return -ENODEV;
      kref_get(&sr->ref);
      return 0;
}
EXPORT_SYMBOL_GPL(wf_get_sensor);

void wf_put_sensor(struct wf_sensor *sr)
{
      struct module *mod = sr->ops->owner;
      kref_put(&sr->ref, wf_sensor_release);
      module_put(mod);
}
EXPORT_SYMBOL_GPL(wf_put_sensor);


/*
 * Client & notification
 */

int wf_register_client(struct notifier_block *nb)
{
      int rc;
      struct wf_control *ct;
      struct wf_sensor *sr;

      mutex_lock(&wf_lock);
      rc = blocking_notifier_chain_register(&wf_client_list, nb);
      if (rc != 0)
            goto bail;
      wf_client_count++;
      list_for_each_entry(ct, &wf_controls, link)
            wf_notify(WF_EVENT_NEW_CONTROL, ct);
      list_for_each_entry(sr, &wf_sensors, link)
            wf_notify(WF_EVENT_NEW_SENSOR, sr);
      if (wf_client_count == 1)
            wf_start_thread();
 bail:
      mutex_unlock(&wf_lock);
      return rc;
}
EXPORT_SYMBOL_GPL(wf_register_client);

int wf_unregister_client(struct notifier_block *nb)
{
      mutex_lock(&wf_lock);
      blocking_notifier_chain_unregister(&wf_client_list, nb);
      wf_client_count++;
      if (wf_client_count == 0)
            wf_stop_thread();
      mutex_unlock(&wf_lock);

      return 0;
}
EXPORT_SYMBOL_GPL(wf_unregister_client);

void wf_set_overtemp(void)
{
      mutex_lock(&wf_lock);
      wf_overtemp++;
      if (wf_overtemp == 1) {
            printk(KERN_WARNING "windfarm: Overtemp condition detected !\n");
            wf_overtemp_counter = 0;
            wf_notify(WF_EVENT_OVERTEMP, NULL);
      }
      mutex_unlock(&wf_lock);
}
EXPORT_SYMBOL_GPL(wf_set_overtemp);

void wf_clear_overtemp(void)
{
      mutex_lock(&wf_lock);
      WARN_ON(wf_overtemp == 0);
      if (wf_overtemp == 0) {
            mutex_unlock(&wf_lock);
            return;
      }
      wf_overtemp--;
      if (wf_overtemp == 0) {
            printk(KERN_WARNING "windfarm: Overtemp condition cleared !\n");
            wf_notify(WF_EVENT_NORMALTEMP, NULL);
      }
      mutex_unlock(&wf_lock);
}
EXPORT_SYMBOL_GPL(wf_clear_overtemp);

int wf_is_overtemp(void)
{
      return (wf_overtemp != 0);
}
EXPORT_SYMBOL_GPL(wf_is_overtemp);

static int __init windfarm_core_init(void)
{
      DBG("wf: core loaded\n");

      /* Don't register on old machines that use therm_pm72 for now */
      if (machine_is_compatible("PowerMac7,2") ||
          machine_is_compatible("PowerMac7,3") ||
          machine_is_compatible("RackMac3,1"))
            return -ENODEV;
      platform_device_register(&wf_platform_device);
      return 0;
}

static void __exit windfarm_core_exit(void)
{
      BUG_ON(wf_client_count != 0);

      DBG("wf: core unloaded\n");

      platform_device_unregister(&wf_platform_device);
}


module_init(windfarm_core_init);
module_exit(windfarm_core_exit);

MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("Core component of PowerMac thermal control");
MODULE_LICENSE("GPL");


Generated by  Doxygen 1.6.0   Back to index